c/EPA
         United States
         Environmental Protection
         Agency
             EPA 600 8-87 004
             January 1987
         Research and Development
Methods for Spawning,
Culturing and Conducting
Toxicity-Tests with Early
Life Stages of Four
Atherinid Fishes:

The Inland Silverside,
Menidiaberyllina, Atlantic
silverside, M. menidia,
Tidewater Silverside,
M. peninsulae and
California grunion,
Leuresthes tenuis

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Methods for Spawning,
Toxicity-Tests  with Ea
Atherinid  Fishes: The
beryllina, Atlantic silvers
silverside, M. peninsulae
                                    EPA/600/8-87/004
                                        January 1987
      (pulturing and Conducting
        ly Life  Stages of  Four
      inland silverside, Menidia
        de, M. menidia, tidewater
        and California grunion,
Leurestftes tenuis
    Douglas P. Middaugh, Michael J. Hemmer and
                Larry R. Goodman
         Environmental Research Laboratory
             Gulf Breeze, Florida 32561
         Office of Research and Development
        U.S. Environmental Protection Agency
               Washington, DC 20460

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                    DISCLAIMER

   This document has been subjected to the Agency's peer and
administrative review, and has been approved for publication as an
EPA document.

The mention of trade names in this document does not imply
endorsement by the U.S. Environmental Protection Agency.
                              11

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                        FOREWORD

Timely assessment of the environmental risks of pesticides and toxic
substances to fish requires that test species be  readily available.
Methods for the acquisition, spawning, culture and testing of the
early life stages of marine and estuarine fishes should be formulated
and presented in a format that will enable the experienced aquatic
biologist to conduct tests  with minimal difficulty.  Moreover, a
compilation of methods should provide for utilization of fishes from
all coastal regions of the United States.

This manual presents methods for field and/or laboratory spawning
of four species of atherinid fishes including:

   • Inland silverside, Menidia beryllina

      Estuarine populations - Cape Cod, Massachusetts to Texas.
      Freshwater populations - States adjacent to Mississippi River
      Basin; and Texas, Oklahoma, California.

   • Atlantic silverside, Menidia menidia

      Estuarine populations - Maine to N.E. Florida.
   • Tidewater silverside, Menidia peninsulae

      Estuarine populations - N.E. Florida to Texas.

   • California grunion, Leuresth.es tenuis

      Coastal populations - San Diego to Los Angeles, California.

Procedures are also presented for culturing and conducting acute
and early-life stage toxicity tests with each of the species. All of the
methods have been used extensively by investigators at the Gulf
Breeze Environmental Research Laboratory. Guidelines provided in
this manual are based  upon a compilation of studies that have been
published in the peer-reviewed literature.
                              111

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                       ABSTRACT

Procedures are presented for spawning, culturing and conducting
acute and chronic toxicity  tests with four atherinid fishes: the
inland silverside, Menidia  beryllina, Atlantic silverside, M.
menidia, tidewater silverside, M. peninsulas, and California
grunion, Leuresthes tennis. Guidelines also are provided for growing
of food organisms (Chlorella sp., Brachionus plicatilis, and Artemia
sp.) that are required for successful  culture and testing of the
atherinid fishes.
                                IV

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               ACKNOWLEDGEMENTS

The authors wish to thank D.A.  Bengtson,  Department of Food
Sciences and Technology, Nutrition and Dietetics, University of
Rhode Island; W.S. Hall, Aquatic Ecology Section, Applied Physics
Laboratory, Johns Hopkins University; and D.J. Klemm, Newtown
Fish Toxicology Laboratory, J.R. Clark, Gulf Breeze Environmental
Research Laboratory, and W.A. Rabert, Environmental Review
Divison, Office of Toxic Substances, U.S. Environmental Protection
Agency for providing a critical review of an early draft of this
document. Steven Foss  drafted the figures and Val Caston typed
several early drafts of this document.

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                        CONTENTS

Foreword 	  iii

Abstract	  iv

Acknowledgements  	  v

   I. Introduction 	  1

   II. Biology of the Atherinids - distribution,
      ecology, reproduction, identification, collection,
      handling, spawning, larval culture	  2
      A.  Inland silverside, M. beryllina  	  2
      B.  Atlantic silverside, M. menidia  	  12
      C.  Tidewater silverside, M. peninsulae  	  18
      D.  California grunion, L. tennis 	  23

  III. Acute toxicity tests, M. beryllina, M. menidia,
      M. peninsulae, and L. tenuis 	  29
      A.  Static tests (96 hours) 	  29
      B.  Flow-through tests (96 hours)  	  30

  IV. Early life-stage toxicity tests, M. beryllina, M. menidia,
      M. peninsulae 	  31
      A.  Seawater  	  31
      B.  Exposure system  	  31

   V. Early life-stage toxicity tests, L. tenuis  	  33
      A.  Seawater  	  33
      B.  Exposure system  	  33

  VI. Batch culture of the alga, Chlorella sp. and
      mixohaline rotifer, Brachionus plicatilis 	  35
      A.  Apparatus used 	  35
      B.  Media preparation and Chlorella sp. culture  	  35
      C.  Culture of B. plicatilis 	  38

 VII. Hatching of brine shrimp, Artemia sp	  40
      A.  Strains used 	  40
      B.  Apparatus required 	  40
                                  VI

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      C. Hatching procedure  	   40
      D. Enumeration ofArtemia nauplii  	   41
      E. Nutritional quality ofArtemia sp	   41

III. References 	   42

  IX.  Appendices  	   49
      A. Selected biogeographical data for occurrence
         of the inland silverside, M. beryllina   	   49
      B. Recommended environmental variables and feeding
         regimes for laboratory spawning of three
         atherinid fishes 	   50
      C. Recommended environmental variables and feeding
         regimes for laboratory incubation and larval rearing
         of four atherinid fishes 	   51
      D. Selected biogeographical data for occurrence
         of the Atlantic silverside, M. menidia  	   52
      E. Selected biogeographical data for occurrence
         of the tidewater silverside, M. peninsulae  	   53
      F. Selected biogeographical data for occurrence
         of the California grunion, L. tenuis  	   54
      G. Recommended test parameters and feeding regimes
         for conducting static or flow-through 96 hr acute
         toxicity tests with  14 day-old atherinid fishes  	   55
      H. Enrichment media for seawater used to grow
         Chlorella sp	   56
                              vn

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                   I. INTRODUCTION

This methods manual provides guidelines for conducting toxicity
tests with four atherinid fishes: the inland silverside, Menidia
beryllina;  Atlantic silverside, Menidia  menidia; tidewater
silverside, Menidia peninsulae; and California grunion, Leuresthes
tenuis.

We have conducted research to  determine optimal conditions for
collecting, handling and transport of the three species of silversides
and for field stripping, fertilization and shipment of embryos of the
California grunion. Methods have been  developed for laboratory
spawning of silversides and for incubation of embryos and culture of
larvae of all four atherinids. Toxicity test methods also  were
developed. The methods described include acute static and  flow-
through procedures as well as early life-stage (ELS) test methods for
each species.

An important aspect of fish  culture  is the availability of adequate
food resources. This manual provides information required for
growth of the mixohaline rotifer, Brachionus plicatilis, and Artemia
sp. nauplii. These two food items are essential for successful culture
and testing of the larval atherinid fishes.

The manual has been formatted to provide a complete synopsis of
culture and testing procedures  for individual  species.  To avoid
redundancy and save space, sections describing procedures for M.
menidia and  M. peninsulae  at times refer the reader to methods
previously described for M. beryllina.

Other procedures for fish transport, culture of embryos and larvae,
and exposure to toxicants may work equally well. Our recommended
methods have been used repeatedly with success at the Gulf Breeze
Environmental Research Laboratory.

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              II. Biology of the Atherinids

A. The inland silverside, Menidia berylllna, and the Mississippi
   silverside, Menidia audens, are now considered conspecific
   (Johnson, 1975; Chernoff et al., 1981).

   1. Geographical distribution — M.  berylima is  a ubiquitous
      resident of estuaries, coastal rivers and numerous lakes from
      Massachusetts to Texas and is also found in the Mississippi
      River Basin (Sisk and Stephens, 1964; Gomez  and Lindsay,
      1972; Clay, 1975; Johnson, 1975; Chernoff et al.,  1981).
      Moreover, it occurs in Clear Lake, California  where  it was
      introduced in 1967 (Cook and Moore,  1970) and  has since
      moved to the Sacramento-San Joaquin River System (Moyle
      et al., 1974), and the Lexington Reservoir (Fisher, 1973). The
      general biogeographic distribution of M. berylllna is shown in
      Figure 1 and a compilation of selected biogeographical data
      are provided in Appendix A. These  data, along with the
      literature citation for each entry, provide a detailed listing of
      potential collection locations for each of the species described
      in this manual.

   2. Ecology and reproduction — M. beryllina is euryhaline, living
      in freshwater lakes, rivers and reservoirs, and  in coastal
      areas at salinities from 0 to 35 %o (Robbins, 1969; Hubbs et al.,
      1971; Echelle and Mosier, 1982).  Although estuarine forms
      seem to  prefer salinities of 19 %« or less (Johnson, 1975;
      Middaugh et al., 1986); in the Laguna Madre, Texas, M.
      beryllina has been found at a salinity of 75 %o and reported as
      abundant at 45  %o (Simmons,  1957). The  duration of
      reproductive activity varies according to geographic location
      and, apparently, water temperature. Sexually mature M.
      beryllina are  found in June  and July  at Woods  Hole,
      Massachusetts  (Rubinoff and Shaw, 1960). Although the
      spawning period is also brief in Rhode Island, lasting for only
      several weeks (Bengtson, 1984) it has been noted  that if M.
      beryllina from these latitudes are  maintained in  the
      laboratory, they will continue to spawn throughout much of
      the year (pers. comm., Bengtson,  Dept. of Food Science  and
      Nutrition, Univ. of Rhode Island, Kingston, 02881). In the
      Chesapeake Bay, spawning occurs from early  April to  late
      September (Hildebrand and Schroeder, 1928),  at  Beaufort,
      North Carolina from March to September (Hildebrand, 1922)
      and in Tampa Bay, Florida, throughout the year with the

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  exception of January and August (Springer and Woodburn,
  1960). In coastal Texas, Gunter  (1950) reported gravid
  females in February  and March at respective  water
  temperatures of 20 and 25°C.  In Lake Texoma, Oklahoma,
  reproduction generally occurs from late March through mid-
  July at water temperatures of approximately  15 to 30°C
  (Mense, 1967; Hubbs et al., 1971; Hubbs, 1982). Populations
  in Lexington Reservoir, California, spawn  from early May
  until mid-September (Fisher, 1973). Clear Lake populations
  spawn from about late March through early July (Cook and
  Moore, 1970).

3. Identification - The inland silverside, Menidia beryllina, and
  the  Mississippi silverside,  Menidia audens, are now
  considered conspecific (Johnson, 1975; Chernoff et al., 1981).
  The largest inland silverside, Menidia beryllina, examined by
  Robbins (1969) was a female 90.7 mm standard length (SL).
  Females attain a larger size than  males. Scales are large,
  usually well imbricated, and with well developed circulii and
  radii. Usually there are not more  than 37-50  scales in the
  lateral series (Robbins, 1969; Chernoff et al., 1981). The first
  dorsal fin has 2-7, usually 4 or 5 spines, with the origin well
  in advance of the anal fin origin and lying over a point above
  the anterior edge of the anus. The second dorsal fin has one
  spine and 7-11, usually 9 or 10, rays. The  anal fin has one
  spine and 13-20, usually 15-17, rays (Robbins, 1969). The gas
  bladder in M. beryllina is  long and translucent (Echelle and
  Mosier, 1982), and extends to a position approximately above
  the fourth anal fin ray (Robbins, 1969). It is bluntly rounded
  posteriorly and is a good characteristic for use in the field to
  quickly identify  M. beryllina and separate this species from
  Menidia menidia and M. peninsulae which have a truncated
  opaque gas bladder.  Another diagnostic characteristic  for
  separating M. beryllina and M. peninsulae is measurement of
  the horizontal  distance between the  origins of the first
  spinous dorsal fin and anal fin (Chernoff et al., 1981). This
  measurement is  s7% of SL in M. beryllina and zl% of SL in
  M. peninsulae. Moreover,  mature and  hydrated M. beryllina
  eggs, 0.9 to 1.1 mm diameter, possess 1  or 2 long-thick
  filaments (length usually is equal to 15 to 30 egg diameters)
  and 1 to 15 short-thin filaments. In contrast, fully hydrated
  Menidia menidia and M.  peninsulae eggs possess 15 to 50
  short-thin filaments and no long-thick filaments. M. beryllina
  also may be taken  in freshwater areas where the brook
  silverside, Labidesthes sicculus, is present. M.  beryllina is
  more robust than L. sicculus. Viewed from above, the
  premaxillary of L. sicculus is pointed, forming a cone shape
  while that of M. beryllina is crescent shaped, not forming a

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  pointed beak. L. sicculus scales are also smaller than those of
  M. beryllina (Blair et al.f 1968).

4. Collection, handling, spawning and transport.

  a. Where — Sexually mature fish generally will be available
    in lakes, rivers and estuarine habitats from March or April
    through August at water temperatures of 15 to '30°C
    (Hubbs, 1982;  Hubbs, 1976; Rubinoff and  Shaw, 1960;
    Hildebrand and Schroeder, 1928; Springer and Woodburn,
    1960;  Gunter,  1945). Certain locales such as the  Upper
    Laguna Madre, Texas have  populations that spawn
    throughout the year (Simmons, 1957) while at northern
    latitudes, such as in Rhode Island estuaries, the breeding
    season may be  as short as two or three weeks in late June
    and early July (Bengtson, 1982). M. beryllina frequents
    shallow waters along shorelines where sandy to partially
    vegetated substrates occur. Beaches, bordering open but
    protected waters, are preferable for collecting. In Lake
    Texoma, M. beryllina is found in areas with a sandy bottom
    (Mense, 1967;  Hubbs, 1982). They are found in a similar
    habitat in Clear Lake, California (Cook and Moore, 1970).
    Elston  and Bachen (1976) made collections in  the
    Lexington Reservoir, California in  a shallow sandy area
    with sparse growth of rooted aquatic plants and a border of
    tule beds, Scirpus spp.

  b. When — The optimal time to collect M. beryllina is during
    early  to mid-morning between  0800 and 1200  hrs. This
    time is  recommended because of the  diel reproductive
    pattern noted for M. beryllina in Lake Texoma where most
    mature fish were ripe between 0800 and 1200 hrs (Hubbs,
    1976). Similar reproductive timing was noted in Lexington
    Reservoir, California where spawning occurred during
    mid-morning over a vegetated gentle slope at water depths
    of 2.5 to 60 cm (Fisher, 1973). This same reproductive
    timing was noted  by Robbins (1969) in Lake Kustis,
    Florida. Moreover, Middaugh et al., (1986) were able to
    determine the sex of individual M. beryllina collected
    during mid-morning from Blackwater Bay, Florida in mid-
    April. Extrusion of ripe eggs  and sperm was possible,
    suggesting that estuarine populations also may be ready- to
    spawn during early to mid-morning.

  c. How - A 1  x 10-m bag seine with knotless 5-mm mesh is
    ideal for collecting. Since M. beryllina typically resides in
    shallow  water  (<1.5 m deep), they are easily captured by
    seining  close to shore.  It is important to avoid total
    beaching of the bag seine  when collecting M. beryllina.
    These fish will  quickly die if removed from water and ripe
    females often abort their eggs if stranded. Ideally, the bag

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  portion of the seine containing captured adults should
  remain in water 5 to 15 cm deep (Middaugh et al., 1986).

d. Spawning in the field.

  1. Refer to Figure 2 for a diagrammatic explanation of the
     procedure outlined below.

  2. Immediately after seining (while still on the beach) --
     Three to five ripe females should be dipped into a bucket
     of water from  the collection site to remove sand  and
     detritus.

  3. Eggs — Females with hydrated eggs are stripped into a
     20 cm diameter glass culture dish  containing ambient
     temperature water (Middaugh and  Lempesis,  1976) or
     directly onto a nylon screen (0.60 to 1.0 mm mesh) which
     is then gently lowered into the culture dish of ambient
     temperature water with the eggs on  the upper surface of
     the screen (Barkman and Beck, 1976). If excessive
     pressure on the abdomen is required to strip eggs, the
     female should be discarded. Mature eggs are clear with
     an amber-green hue.

  4. Milt - Several males should then  be  stripped into a
     seperate culture  dish containing  ambient temperature
     water.  Eggs are then fertilized by pouring water from
     the dish containing sperm into the dish containing eggs.
     Upon contact with water, adhesive threads on mature
     eggs uncoil, making enumeration and separation
     difficult. If eggs  are stripped directly into the culture
     dish, one end of a nylon string may be dipped into the
     dish and gently rolled so the embryos adhere (Middaugh
     and Lempesis, 1976).  The Barkman and Beck (1976)
     technique  for attaching the eggs  to nylon screening
     minimizes the natural  clumping tendency due to
     entanglement of the filaments on Menidia eggs and is
     recommended.

  5. Strings of embryos or embryos on screens - These are
     transported to the laboratory by placing in an insulated
     glass or stainless steel container half-filled with water
     from the collection site.

  6. In the laboratory - Embryos should be suspended in a 10
     to 20 1 all-glass container. The temperature and salinity
     of the  water at the collection site should be used as
     guidelines for holding conditions in the laboratory. If
     convenient, water from the collection site should be used
     for holding embryos in  the lab. Since M.  beryllina
     embryos are  euryhaline and eurythermal, slight
     changes in salinity and incubation temperatures (to a
     new constant salinity and temperature) are acceptable,

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              FIELD SEINING
                                          HAND STRIP EGGS
                                                              HAND STRIP SPERM
                                                           INTO A GLASS CULTURE
                                                           DISH- THEN ADO TO E06S
                                             06-1 Omm
                                            NYLON SCREEN
                               ADULTS DIPPED
                               TO REMOVE SAND
                               AND DETRITUS
           HOLD EMBRYOS IN IO8
           AQUARIUM FOR 6- 10
           DAYS, 22-25'C
                                            WIDE-MOUTH
                                            VACUUM BOTTLE
                                                              WAIT 10-15 MINS
                                                              RNSE 3 TIMES
                                     TRANSFER SCREEN
                                     WITH EMBRYOS
                                                    ~X PARTIALLY FILLED
                                                       WITH WATER
 SCREEN WITH
s ATTACHEl
 EMBRYOS
                                           GLASS LINED
                                                OR
                                          STAINLESS STEEL
       TRANSFER LARVAE TO
       ALL GLASS  AQUARIUM
       WHEN 4-6 DAYS OLD
         USE  SYPHON TUBE
         GLASS  TUBE OR BEAKERS
         DO NOT USE DIPNETS
                                  ACUTE  TOXICITY
                                      TESTS
SCREENED
 DRAIN
  DAYS 1-5 FEED 10,000 ROTIFERS/J! 2X DAILY
  DAYS 6- 14 FEED 5,000 ARTEMIA NAUPLII/* 2X DAILY
Figure 2.      Diagrammatic explanation of procedure for collection,
                fertilization, transport,  culture  and  testing  of
                embryonic and larval stages ofMenidia.

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     provided the constant laboratory regime is not likely to
     result  in  salinity or  thermal stress.  The optimal
     temperature for survival of embryos and growth  of
     young larvae is 25°C (Hubbs et al., 1971; Middaugh et
     al., 1986). A salinity of 15 %0 produced the best survival
     and growth of larval M. beryllina from parental stock
     taken from a brackish water (1-5 %o) habitat (Middaugh
     etal.,1986).

e. Transport of adults to the laboratory.

  1. Handling — Adults should be removed from the bag end
     of the seine by hand and placed immediately in a bucket
     containing 12 to 15 1 of ambient temperature water from
     the collection site. Not more than 25 adults should be
     placed  in a bucket at any one time and these should be
     quickly and gently transferred to the transport tank.

  2. Transport  tank — A container of 100 to  350 1 volume
     with smooth sides (fiberglass, rigid  styrofoam or
     stainless steel) should be used to transport adults to the
     laboratory. A loading capacity of 5.Og I-1 (2adultsof ~2.5
     g each) should  not be exceeded.  The transport tanks
     should  be partially filled with water before addition of
     adult fish. Vigorous aeration from  2 to  3  airstones
     should be provided continuously using a  battery-
     operated portable aerator.

  3. Before  transport - Care should be taken  to prevent the
     introduction of sand, mud,  clay or any other abrasive
     materials to the transport tank while loading of ambient
     water or fish.

  4. At the  laboratory  - Adult fish should  be dipnetted with
     fine  mesh nets  and  transferred  quickly  from the
     transport tank to buckets containing 12 to 15 1 of water,
     then carried to the  laboratory spawning  system and
     divided among the brood tanks as described in the next
     section.

f. Laboratory spawning.

  1. Spawning system  - Inland silversides, M. beryllina may
     be spawned in  the laboratory on a year-round basis.
     Procedures described by Middaugh et al.,  (1986) provide
     for maintenance of a brood  stock of 50 individuals, sex
     ratio 1:1 (i.e.,  25 males +  25 females) in  each of 2
     circular fiberglass tanks, diameter 1.3  m, water depth 38
     cm. A  filter reservoir system is employed to  maintain
     water quality  and a March TE5C MD  pump (March
     Manufacturing Co., Glenview, Illinois) circulates water
     from the filter-reservoir system to each spawning tank
     (Figure 3). A once-through system without the filter-

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FigureS.    Laboratory spawning system utilized  with Menidia
             beryllina, M. peninsulae and M. menidia, A. 1.3 m
             diameter holding tanks;  B. seawater  circulation
             pump; C. filter-reservoir tank; D. seawater discharge
             lines from circulating pump; E. shunt-return line to
             filter-reservoir;  F. drain-return line from  holding
             tanks routed into reservoir tray; G. reservoir filter-
             tray.  The tray  contains several strata of filter
             material including (from top) aquarium filter fiber (2-
             3 cm deep), activated charcoal (1-2 cm deep), coarse
             stone gravel (2-3 cm deep) and crushed oyster shell (1-
             2 cm deep).

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  reservoir can also be used if the incoming water is of
  sufficiently good quality. Flow  rates are adjusted to
  provide a surface current velocity of 4 to 8 cm sec-1 in
  each holding tank. Water flows out of the bottom of each
  tank through an inverted standpipe. A  perforated air
  tube positioned at the outer bottom edge of each inverted
  standpipe maintains dissolved oxygen at >  5.0 mg I-1
  and produces a gentle upwelling current.

2. Feeding schedule -- Fish in each holding tank are fed 8.0
  g of Tetramin (Standard Mix-large flake) food  each
  morning, 0800 to 0900, 4.0 g at  1000 to 1100, 4.0 g at
  1400 to 1500 and a final 8.0 g feeding at 1500 to  1700
  hrs. Daily feedings may be supplemented between  1100
  and 1200 hrs with -150,000 Artemia nauplii. At  least
  once each week, excess food is siphoned from the bottom
  of each tank, and aquarium filter fiber  and activated
  charcoal in  the filter-reservoir  system  changed.
  Approximately  20% of the water in each  system is
  removed weekly and replaced with temperature and
  salinity adjusted water.

3. Water quality — The spawning system should have
  water quality similar to that at  the  collection site. M.
  beryllina adults from freshwater habitats such as Lake
  Texoma, Oklahoma; Clear Lake, California; or Lake
  Eustis,  Florida should be maintained in water with a
  hardness, pH,  alkalinity, and total organic carbon,
  similar to the water from which they were collected. In
  contrast, fish collected from estuarine locales should be
  maintained at salinities similar to those measured at
  the collection location.

4. Water temperature and salinity - These  environmental
  variables should resemble values -encountered at the
  collection location.  It appears that reproduction in M.
  beryllina occurs over a temperature range of ~ 15 to 30°C,
  with 25°C considered optimal for embryo development
  and survival. Thus adult brood stock should be held at
  25°C  after  an  appropriate  acclimation  period if
  collections are made early in the reproductive season
  (i.e., when water temperatures may be low). M. beryllina
  taken from Blackwater Bay, Florida, temperature 23.7
  to 26.3°C, salinity 3 to 5 %o are routinely held at  25°C
  and 5 %o while in brood tanks (Middaugh et al., 1986).

5. Photoperiod and light intensity —  A photoperiod of
  13L:11D is recommended for Menidia brood stock with a
  light intensity of 300 lux provided by two  banks of 16 cm
  long 40 watt "cool white" fluorescent tubes mounted 1.5
  m above holding tanks. Timer controlled  lights are
                     10

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     turned on at 0600 and off at 1900 hrs. Pairs of spawning
     tanks must be isolated from outside ambient light and
     general  disturbances by light-tight curtains. These
     curtains remain partially open to facilitate easy feeding
     of adult  fish  during daytime, but are tightly closed at
     night. A small exhaust fan is mounted on the  plywood
     ceiling of our enclosure to prevent  a buildup of excess
     heat (from the  water circulation pump) and humidity
     from the holding tanks.

  6. Combinations of spawning signals - We recommend
     running the  circulation pump continuously.
     Introduction  of a 13L:11D photoperiod (lights  on  0600
     and  off 1900 hrs)  is used to  mimic the  natural
     photoperiod during spring-early summer when
     reproductive activity is  evident throughout the
     geographical range of M. beryllina. M. beryllina tend to
     spawn throughout the day and night. However, in our
     studies most  egg release appears to occur between 0800-
     1200 hrs each day for populations  collected from
     freshwater lakes and reservoirs, and 1800-2300 hrs for
     estuarine populations. The laboratory spawning time for
     freshwater populations is similar to times of spawning
     in nature  (Hubbs,  1976; Robbins,  1969). Daily egg
     production from a tank  containing  25 females and 25
     males (from an estuarine locale), during 13 days when
     eggs were enumerated, ranged from 659 to 4,649
     (x = 2,316)(Middaugh et al., 1985). Egg production was
     similar for a  population of fish taken from  Lake Chicot,
     Arkansas (Middaugh and Hemmer, unpublished).

  7. Spawning substrates — Polyester aquarium filter-fiber
     substrates, size —15 cm long x 10 cm wide x 10 cm thick
     are  suspended just below the water's surface and  in
     contact with the side of each holding tank. A synopsis of
     recommended environmental variables for spawning M.
     beryllina and other silversides in the laboratory  is
     provided in Appendix B.

g. Culture of laboratory spawned Menidia beryllina.

  1. Fertilized eggs - They should be  removed from the
     surface of the spawning substrate,  generally between
     1300 and 1400 hrs daily. No effort  should be  made  to
     tease individual eggs  from the substrate,  rather,
     concentrations of eggs and accompanying substrate are
     removed from the main body of the spawning substrate
     with forceps. It should be noted, however, that
     minimization of the amount of spawning substrate
     removed with the embryos is desirable.
                       11

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        2. Embryos -- Developing embryos that are attached to
          polyester substrates are suspended in a 10 to 20 1 glass
          aquarium containing 8 to 18 1 of water adjusted to the
          temperature (25°C) and salinity (freshwater to ~20 %o) at
          which adult brood fish were held and eggs spawned and
          fertilized in the laboratory.

        3. Water temperature and salinity -- Utilization of a single
          temperature and salinity regime for spawning adults,
          embryo incubation, and larval culture and testing
          eliminates questions of acclimation and is often helpful
          because the same source of water can be used in the
          various production and testing systems.

        4. Transfer -- Newly hatched larval M. beryllina should be
          maintained and fed in the 10 to 20 1 glass culture
          container for 4 to  6 days after hatching, with water
          temperature and salinity  appropriately adjusted. A
          density of 5 to 10 larvae I-1 of water is desirable, thus a
          maximum of 180 larvae should be placed in a  tank
          containing 18 1 of water. A 1.5  cm inside diameter (I.D.)
          glass tube, approximately 45  cm in length, equipped
          with a rubber squeeze bulb is used to make transfers of 4
          to 6 day old Menidia. Alternatively a small siphon tube,
          3 cm I.D. x 1.5 m in length may be used to siphon fish
          from the hatching aquarium to the grow out tank. We
          prefer to transfer larvae to 200 ml  beakers for
          enumeration and then pour the contents into a 20 to 40 1
          tank. Under no circumstances should a dipnet be used to
          transfer larval M. beryllina,. Mass  mortalities will occur
          if a dipnet is used.

        5. Feeding — The mixohaline rotifer, Brachionus plicatilis,
          must be provided on the day that M. beryllina hatch. Two
          feedings, one between 0800 and 0900 hrs and a second at
          1400 to 1500 hrs are required. At each feeding, rotifers
          are added at a rate of 10,000 I-1 of water in the holding
          aquarium. Thus an 18 1 volume would require the
          addition of 180,000 rotifers, twice daily. This regime is
          continued through the fifth day after larval M. beryllina
          hatch. On days six through  fourteen,  5,000 newly
          hatched (<8 hr old) Artemia nauplii I-1 are added each
          morning and afternoon.  A synopsis of recommended
          environmental variables  for laboratory incubation of
          embryos and larval culture is provided in Appendix C.

B. Atlantic silverside, Menidia menidia.

    1. Geographical distribution -- M. menidia ranges as far north
      as the Magdalen Islands, Province  of Quebec, Canada (Cox,
      1921). The southern range is limited to the Atlantic coast of
                              12

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  northern Florida (Gosline, 1948; Robbins, 1969).  Johnson
  (1975) collected a few M. menidia as far south as New Smyrna
  Beach, Florida where it seems to  intergrade with the
  tidewater silverside, M. peninsulae, which is generally found
  from Daytona Beach, southward (Chernoff et al., 1981). M.
  menidia  has been taken from Scarborough Harbor and off
  Todd Point in southern Maine (Robbins, 1969). It is a resident
  of Essex Bay, Massachusetts (Conover and Kynard,  1981),
  southern Rhode Island estuaries (Bengtson et al., 1986), and
  is common at Woods Hole, Massachusetts (Kendall, 1902). It
  is also found in southern Connecticut  estuaries opening into
  Long  Island Sound (Cadigan and Fell, 1985). Moreover, M.
  menidia occurs in the lower regions of Chesapeake  Bay
  tributaries (Bayliff 1950; Robbins, 1969). Massman  (1954)
  collected adults approximately  54 km upstream from
  brackish water in the James, Rappahannock and Pamunkey
  Rivers, Virginia. An offshore migration of M. menidia north
  of Cape Hatteras occurs in fall and winter  as the estuarine
  and nearshore water temperatures  drop to about  6  to 8°C
  (Conover and Murawski, 1982). South of Cape Hatteras, M.
  menidia was extremely abundant and  the only fish occurring
  in shallow water throughout the winter (Hildebrand, 1922).
  In South Carolina, M. menidia is a year-round resident of
  intertidal creeks (Cain and Dean, 1976; Shenker and Dean,
  1979) and  is found in the surf zone of barrier  beaches
  throughout the winter (Anderson et al., 1977). The general
  distribution of M. menidia is shown in Figure 4 and a list of
  selected biogeographical data, that should aid in selection of
  collection sites, is provided in Appendix D.

2. Ecology and reproduction -- M.  menidia is euryhaline  and
  eurythermal, living in the upper reaches of rivers  in the
  Chesapeake Bay (Massman,  1954) and migrating offshore
  some  50  km during the colder months at northern  latitudes
  (Conover and Murawski, 1982). De  Sylva  et al.,  (1962)
  collected M. menidia at salinities ranging from 2 to 35 %o in
  the Delaware Bay and found the greatest abundance at water
  temperatures from 12 to 30°C. Bayliff (1950) observed  that
  adults were less  numerous in shallow waters of the
  Chesapeake Bay during fall as water  temperatures declined
  to less than 12°C; at 6°C or lower, few  M. menidia were to be
  found in the shallows. Hildebrand and  Schroeder (1928) were
  able to collect specimens  at a depth of approximately 50 m
  during  the winter in Chesapeake Bay.  A  decline in
  abundance  was noted  at  temperatures below 10°C  in the
  North Edisto River  estuary of South  Carolina (Middaugh,
  unpublished). Moreover, Dahlberg (1972) reported that M.
  menidia occurred in a Georgia estuary  at water temperatures
  from 7 to 31.5°C but observed that adults became scarce when
  water temperatures dropped below  12°C. M,  menidia is an
                         13

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                               Atlantic silverside,  Men id I a  menidio
Figure 4.    Biogeographica!  distribution of the Atlantic silverside, Menidia menidia.

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  opportunistic omnivore,  feeding  on mysids, copepods,
  molluscan larvae,  annelid worms, amphipods, young
  gastropods, crab larvae, diatoms and other fishes  including
  its own young (Kendall, 1902; Bayliff, 1950; De Sylva et al.,
  1962;  Mulkana, 1966). Sexually mature adults spawn from
  March through August depending upon the latitude. Ripe fish
  have been found in June at Prince  Edward Island, Canada
  (Leim and Scott, 1966), and in June and July at Woods Hole,
  Massachusetts  (Kuntz  and Radcliffe, 1918;  Rubinoff and
  Shaw,  1960;  Kendall,   1902).  In  Salem  Harbor,
  Massachusetts,  Conover and Kynard (1984) noted that  M.
  menidia had a spawning periodicity that coincided with new
  and full moons. Intensity and frequency of spawning was
  correlated with the height of daytime high tides.  Breeding
  occurred from late-April through June at water temperatues
  of 9 to 21°C.  Daytime spawners deposited eggs on mats of
  intertidal, filamentous algae. At the Pataguanset River
  estuary in eastern Connecticut, Cadigan and  Fell  (1985)
  reported reproductive activity in M.  menidia from early-May
  until late-July and observed that water temperature was an
  important factor influencing reproductive activity. An
  apparently critical lower temperature for reproduction, 16°C,
  was reached in mid-late May. Interestingly, Middaugh (1981)
  reported that 16°C was required for spawning to occur in M.
  menidia from the North Edisto River estuary  in  South
  Carolina.  Spawning generally began in early to mid-March
  when the critical minimum water temperature was reached
  and ended in June or July  as estuarine water temperatures
  exceeded  30°C. In South Carolina estuaries, M. menidia
  primarily spawns during a  3 to 4 day period on daytime high
  tides following new and full moons  (Middaugh, 1981;
  Middaugh et al., 1981). Eggs are deposited on a variety of
  upper intertidal substrates including, Spartina  alterniflora,
  detrital mats and in abandoned crab burrows along erosional
  scarps (Middaugh et al., 1981).

3. Identification -- The Atlantic silverside, Menidia menidia is
  the largest species in the genus.  The largest  specimen
  examined by Robbins (1969) was a 117 mm SL female. Males
  are generally smaller than females. Scales are small to
  moderate in  size, well inbricated, and usually with well
  developed circulii. Branchial lateral line scales are usually
  41-47, post pectoral lateral  line scales usually  42-46;
  predorsal scales 18-22. The first dorsal fin has 3-7, usually 4
  or 5 spines; origin is over  the posterior  edge  of the anus or
  anal fin origin. The second dorsal fin has one spine and 7-11,
  most frequently 8 or 9, rays. The anal fin is long with one
  spine and  19-29,  usually 21 to 26, rays. The  air bladder
  scarcely reaches a point above the anal fin origin  and is
  opaque and abruptly truncate in shape posteriorly. The snout
                          15

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  is moderately blunt or sub-conic to angular and is usually
  greater than eye length. Jaws are equal. The distal tip of
  mandible does not project beyond tip of premaxillary, and the
  premaxillary is rounded anteriorly (Robbins, 1969). Mature
  and hydrated M. menidia eggs are 1.0 to 1.2 mm  in diameter
  and bear a cluster of 15 to 50 thin filaments and no thick
  filaments.

4. Collection, handling, spawning and transport.

  a. Where -  North of Cape Cod sexually mature fish will
     generally be  available in estuaries during  late April
     through June  or July, at water temperatures of 2 to 21°C
     (Kendall, 1902; Kuntz and Radcliff, 1918; Rubinoff and
     Shaw, 1960;  Bengtson,  1985). At  Salem  Harbor,
     Massachusetts sexually mature adults were taken from
     late April through June at water temperatures of 9 to 21°C
     (Conover and Kynard, 1981). From Cape Cod southward to
     Florida, it appears  that water  temperatures  >16°C are
     required for spawning in spring (Cadigan and Fell, 1985)
     and that reproduction ceases as water temperatures
     approach 30°C (Middaugh, 1981).

  b. When — Menidia menidia should be collected just prior to
     natural spawning runs. These runs at all latitudes  appear
     to occur 25 during daytime and  are timed at, or just after,
     high tides (Middaugh, 1981; Conover and Kynard, 1984).
     Generally, the 1 to 4 day period after new or full moons is
     best for collecting. High tides will occur between —0800 and
     1200 hrs on these days.

  c. How ~ Refer to section II. A. 4. c. for Menidia beryllina.

  d. Spawning in the field.
     1. Immediately after seining -- Refer to sections II. A. 4. d.
     1-6. for Af. beryllina.

  e. Transport of adults to the laboratory.
     1. Adults ~ Refer to section II. A. 4. e. 1-4. for M. beryllina.

  f.  Laboratory spawning.

     1. Spawning  system —  Atlantic  silversides, Menidia
       menidia, may be  spawned in the laboratory during the
       natural reproductive season. Procedures  described by
       Middaugh and Takita (1983) should be utilized. The
       system described by Middaugh and Hemmer (1984) and
       Middaugh et al., (1986) for spawning M. peninsulae and
       M.  beryllina (Fig. 3) is also suitable for  laboratory
       spawning of Menidia menidia (Middaugh and Hemmer,
       unpublished).
                          16

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   2. Feeding schedule - Refer to section II. A. 4. f. 2. for M.
     beryllina; and Appendix B.

   3. Water quality -  The pH,  total organic carbon, and
     ammonia in the spawning system should be maintained
     at levels similar to the collection location.

   4. Water temperature and  salinity — M. menldia from
     northern latitudes, north of Cape Cod, should be held at
     18 to 24°C (Conover and Kynard, 1981) while those from
     south of Cape Cod should be held at 20 to 25°C (Cadigan
     and Fell, 1985; Middaugh, 1981). Reproductively active
     M. menidia occur in freshwater (Massman, 1954) and in
     nearly full  strength seawater (Anderson et al., 1977;
     Middaugh 1981). The salinity in spawning tanks should
     be similar to that at the collection site, provided there is
     evidence that M. menidia  is reproductively active where
     collected.  Middaugh  and Takita  (1983)  utilized
     temperatures ranging from  16 to 25°C and a salinity of
     30 ±  2 %o  in laboratory spawning studies  with  M.
     menidia. In contrast,  Conover and Kynard  (1984)
     reported laboratory spawning at 13 to 24°C  during May
     through July for adults collected from Essex Bay,
     Massachusetts.

   5. Photoperiod and light intensity -- Refer to section II. A.
     4. f. 5. for M. beryllina.

   6. Combinations of spawning signals  — "Tidal" signals,
     interruptions of the current velocity, are accomplished
     by using an  electrical timer  to turn off the  water
     circulation pump for 1 hr at the specified times of 1200 to
     1300 and 2400 to  0100  hrs. M. menidia is  sensitive to
     interruptions in current velocity that mimic conditions
     during slack high tides in nature. They will spawn in
     the  labortory during daytime  1200 to 1300  hrs in
     response to  the interruption in current velocity, but not
     at night, between  2400 and  0100 hrs when  the
     circulation  pump is  also turned off (Middaugh and
     Takita, 1983;  Middaugh, 1981).  A  synopsis  of
     recommended environmental variables for spawning M.
     menidia in the laboratory is provided in Appendix B.

   7. Spawning substrates -- Refer to section II. A.  4. f. 7.

g.  Culture of young Menidia menidia.

   1. Fertilized eggs and embryos - Refer to section II. A. 4. g.
     1-2. for M. beryllina.

   2. Water temperature and salinity -- Utilization of a single
     temperature and salinity regime for spawning adult M.
     menidia; and for embryo incubation, larval culture and
                       17

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          testing is advisable. This procedure minimizes questions
          of acclimation and is often helpful  because the same
          source of water can be used in the  various production
          and testing systems.  For northern  latitudes we
          recommend a culture temperature of 22°C and salinities
          of 25 to 30 %o, unless environmental variables  vary
          widely from these parameters at the locale where fish
          are collected. For southern latitudes  (south of Cape Cod)
          we recommend a temperature of 25°C and salinities of 25
          to 30 %o,  again with the caveat for environmental
          variables.

        3. Transfer — Refer to section II. A. 4. g. 4. for M. beryllina.

        4. Feeding -- Refer to section II. A. 4. g. 5. for M. beryllina.
          However,  Middaugh and Lempesis (1976) were able to
          obtain acceptable (70%) survival of M. menldia larvae by
          feeding them on the day-of-hatch and daily thereafter
          with very young (<8 hr  old) Artemia nauplii. Similar
          results were reported by Barkman and Beck (1976) and
          Conover and Kynard (1981). The reader is cautioned: It
          is absolutely essential to begin feeding M. menidia
          larvae with  young Artemia nauplii on the day that
          Menidia hatch. A one day delay in adding Artemia
          nauplii will  result in markedly reduced  survival of
          larval M.  menidia (Middaugh and Lempesis, 1976). If
          the use of Artemia nauplii alone (without initial feeding
          of Brachionus sp.) is unsuccessful then procedures
          outlined in section II. A. 4.  g. 5. should be utilized. A
          synopsis of recommended environmental variables for
          laboratory incubation of embryos and larval culture is
          provided in Appendix C.

C. Tidewater silverside, Menidia peninsulae,  recently recognized
   as a distinct species (Johnson, 1975; Chernoff et al., 1981) was
   once considered conspecific  with Menidia beryllina (Gosline,
   1948; Robbins, 1969). These two atherinids are often found in
   close proximity in estuaries along  the  southeastern  coast of
   Florida and throughout the Gulf of Mexico (Echelle and Mosier,
   1982; Lucas, 1982). The general distribution of M. peninsulae is
   shown in Figure 5 and a list of selected biogeographical data are
   provided in Appendix E. This list should aid in the identification
   of appropriate collection sites.

   1. Geographical distribution - M. peninsulae has a  disjunct
      distribution extending from Daytona Beach, Florida to Horn
      Island, Mississippi and Galveston Bay, Texas to Tamiahua,
      northern Veracruz, Mexico (Johnson 1975; Chernoff et al.,
      1981).

   2. Ecology and reproduction - Menidia peninsulae along the
      northern part of its range intergrades with M.  menidia. At
                              18

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                                       Tidewater silverside,  Menidia  peninsulae
<£>
         FigureS.    Biogeographical distribution  of the  tidewater silverside, Menidia peninsulae.

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  Fort George Inlet, Duvall Co., Florida, collections yielded 99%
  Af. menidia. However, at Flagler Beach, Flagler Co., Florida,
  the ratio  was 63% M. menidia, 20%  hybrids and 19% M.
  peninsulae. In contrast, a more  southerly  location,
  Melbourne, Brevard Co., yielded no M.  menidia or hybrids
  and 100% Af. peninsulae  (Johnson,  1975). Moreover, Af.
  peninsulae and Af. beryllina are often found in close proximity
  in estuaries along the southeastern coast of Florida and in the
  Gulf of Mexico (Echelle and Mosier, 1982; Lucas,  1982).
  Despite sympatric occurrence and collection of Af. beryllina
  and Af. peninsulae in the same seine haul at four localities;
  two in Florida and two in Texas, Johnson (1975) observed that
  the species were discrete in these areas. Collections yielded a
  very low frequency of hybridization. Although M. peninsulae
  has been  collected at salinities of less than 5  %o  to greater
  than 35 %<>; Johnson (1975), Echelle and Mosier (1982) and
  Middaugh et al., (1986) observed that M. peninsulae typically
  resided at salinities of  15 %o or greater while Af. beryllina
  generally occurred at salinities of 19 %o or less. In the Crystal
  River, Florida  locale,  Lucas (1982) observed  that M.
  peninsulae was present throughout much of the  year, but
  disappeared during December and January, temperature 6.0
  to 17.0°C, salinity 22 to 24 %0 and in  July, water temperature
  30.7°C, salinity 28 %o. In contrast M. peninsulae from the
  Pensacola, Florida locale were present in most months but
  disappeared from the shoreline in December  and January
  when water temperatures were below 12°C  (Middaugh and
  Hemmer, 1986a). Lucas (1982) described three feeding stages
  for M. peninsulae from Crystal River, Florida. In early spring,
  young-of-the-year fed on tychoplankton and detritus. During
  late spring through  winter, calanoid copepods and  cypris
  larvae were selectively eaten.  Reproductively active M.
  peninsulae fed primarily on amphipods and larval silversides
  during February and March.  A reproductive peak  was
  observed  only in the spring, no such peak was apparent
  during fall. Middaugh and Hemmer  (1986a)  observed
  spawning during March at low tide on a red alga, Ceramium
  byssoideum, which was growing in the cracks and crevices of
  a rocky substrate just below the  low  tide line. The annual
  reproductive cycle of Menidia peninsulae from Santa Rosa
  Island, Florida extends from February through July or
  August with the greatest spawning activity during March
  through June at water temperatures of 16.7 to 30.8°C.

3.  Identification — While differences in  M. peninsulae and M.
   beryllina are diagnostically clear, these differences are
   difficult  to express in terms of individuals (Johnson,  1975).
   One of the best diagnostic characters for M. peninsulae is the
   horizontal distance between the origins of the first spinous
   dorsal and anal fins. In Af. peninsulae, this distance is >7%
                          20

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   of SL while in M. beryllina the distance is  <7% of SL
   (Chernoff et al., 1981; Middaugh et al., 1986). Chernoff et al.
   (1981)  reported measurements  of this distance  in M.
   peninsulae primary type material of 9.3% and 10.7% SL; in
   M. beryllina 5.7% and in M. audens (now considered M.
   beryllina) 4.4% SL. The least destructive way to identify live
   M. peninsulae and M. beryllina is by the relative posterior
   extension of the gas bladder. In M. peninsulae the opaque
   gas bladder is truncated and extends to the first to third soft
   anal  ray (Johnson, 1975;  Echelle and Mosier,  1982). In
   contrast, the translucent  gas bladder of  M. beryllina is
   bluntly rounded and  extends to a position approximately
   above the fourth or fifth soft anal fin ray. The fully hydrated
   eggs  of M. peninsulae are  0.9 to 1.1 mm in  diameter  and
   possess 15 to 50 short-thin filaments and no long-thick
   filaments.

4.  Collection, handling, spawning and transport.

  a. Where — Sexually mature fish will generally be available
     from  early March through late June  or early July
     (Middaugh  et al.,  1986). M. peninsulae frequents shallow
     waters along shorelines where sandy to partially  vegetated
     substrates occur and prefers locales where salinities are
     S15 %o (Johnson, 1975).

  b. When -- On several occassions, M. peninsulae  has been
     observed spawning on morning (0730 to 1130 hrs) slack low
     tides.

  c.  How — Refer to section II. A. 4. c. for M. beryllina.

  d. Spawning in the field.

     1. Immediatedly after seining -- Refer to section II. A. 4. d.
       1-6. for M. beryllina.

  e.  Transport of adults to the laboratory.
     1. Adults - Refer to section II. A. 4. e. 1-4. for M. beryllina.

  f.  Laboratory spawning.

     1. Spawning system -- Tidewater silversides,  Menidia
       peninsulae, may  be  spawned  in the laboratory
       throughout the  year. The system described in Figure 3
       and section II. A. 4. f. 1.  should be utilized.

     2. Feeding schedule  - Refer to section II. A. 4. f. 2. for M.
       beryllina.

     3. Water quality - Refer to section II. A. 4. f.  3. for M.
       beryllina.
                          21

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  4. Water temperature and salinity — These  variables
    should be similar to that from the  collection site. M.
    peninsulae from the the Santa Rosa Island locale,
    collected at 22°C and 23 %o were successfully maintained
    and spawned in the laboratory at 24°C (22.1  to 25.4°C)
    and 26 %o (23 to 28 %o) Middaugh et al., (1986).

  5. Photoperiod and light intensity - Refer to section II. A.
    4. f. 5. for M. beryllina.

  6. Combinations of spawning signals  - "Tidal" signals,
    interruption of the 8 cm sec-1 current velocity in holding
    tanks should occur at 1200 to 1300 and 2400 to 0100 hrs.
    These interruptions in current velocity are accomplished
    by  using an electrical timer to turn off the circulation
    pump for 1 hr at the specified times of 1200 to 1300 and
    2400  to 0100 hrs.  Menidia peninsulae apparently is
    sensitive to interruptions in current  velocity that mimic
    conditions during slack low  tides in nature (Middaugh et
    al., 1986).  They will spawn in the  laboratory during
    nightime  (2400 to 0100  hrs) in  response to the
    interruption in current velocity, but  not during daytime
    from  1200 to 1300 hrs when the circulation pump is also
    turned off (Middaugh and Hemmer,  1984;  Middaugh et
    al., 1986).

  7. Spawning substrates - Refer to section II. A. 4. f. 7. for
    M. beryllina. A synopsis of recommended environmental
    variables for spawning M. peninsulae in the  laboratory
    is provided in Appendix B.

g. Culture of young Menidia peninsulae.

  1. Fertilized eggs - Refer to  section II. A. 4. g. 1. for M.
    beryllina.

  2. Embryos -- McMullen and Middaugh (1985) learned that
    M. peninsulae embryos from Santa Rosa Island, Florida,
    incubated at 20°C,  showed poor hatchability and post-
    hatch survival and growth.  They concluded that optimal
    conditions for embryo incubation and subsequent larval
    growth and survival are 25°C and 30  %o.

  3. Water temperature and salinity - Utilization of a single
    temperature and salinity regime for spawning adult M.
    peninsulae', and for embryo incubation, larval culture
    and testing is advisable.  This procedure minimizes
    questions of acclimation and is often helpful because the
    same source of water can be used in  the various
    production and testing systems. For M. peninsulae we
    recommend a culture temperature of 25°C and salinity of
    30 %o. This recommendation is based upon the work of
    McMullen and Middaugh (1985)  who found this
                        22

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          combination to  be optimal for  larval survival  and
          growth, and upon the successful spawning  of M.
          peninsulae at a similar temperature and  salinity
          (Middaugh and Hemmer, 1984; Middaugh et al., 1986).

        4. Transfer -- Refer to section II. A. 4. g. 4. for M. beryllina.

        5. Feeding — Refer to section II. A. 4. g. 5. A synopsis of
          recommended environmental variables  for laboratory
          incubation of embryos and larval culture is provided in
          Appendix C.

D. California grunion, Leuresthes tenuis.

   1. Geographical distribution - L. tenuis ranges  from Monterey
      Bay, California to Bahia Magdalena on the outer coast of Baja
      California Sur (Moffatt and Thomson, 1975). The general
      distribution of L. tenuis is shown in Figure  6 and  a  list of
      selected biogeographical data are provided in Appendix F.
      This  list identifies locations where L. tenuis has been
      collected.

   2. Ecology and reproduction — L. tenuis is perhaps  the best
      known of the four atherinid fishes described  in this manual
      because of its unique  reproductive behavior. Adult L.  tenuis
      reside in near-shore waters of southern California  where
      annual water temperatures range from  12 to 28°C  (Moffatt
      ;>nd Thomson,  1975). They  are surface-dwelling  fishes
      (Reynolds et al., 1977) that attain a maximum length  of 150
      to 180 mm (Walker, 1952). Spawning generally occurs from
      late February  through August. L. tenuis spawns in a sand
      substrate at the approximate time of new and full moons
      (Middaugh et al., 1983). Spawning runs  take place  at night
      and are timed just after the highest high tides during each
      semilunar period, subsequent high tides and wave  action
      result in depositon of sand over  the incubating embryos
      (Moffatt  and  Thomson,  1978;  Middaugh et al., 1983).
      Approximately 2 weeks after deposition, developed  embryos
      are washed out of the  sand by the next series of high tides of
      the same or greater height (Shepard and  LaFond, 1940). The
      buried embryos are protected from thermal stress and remain
      relatively moist even though they usually are not inundated
      for a week or more during  incubation (Walker,  1949;
      Middaugh etal., 1983).

   3. Identification - The California grunion, Leuresthes tenuis,
      grows to 143 mm SL or larger (Moffatt and Thomson, 1975;
      Clark, 1925). It is greenish above and silver on the sides with
      a dark lateral stripe.  Scales along the mid lateral band  are
      highly and irregularly crenulate. Lateral scale range  is 69-
      80, x = 75 (Moffatt and Thomson, 1975) with 7-9 scales
      between the  first and second  dorsal fins (Miller and Lea,
                             23

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                       California grunion,  Leuresthes tenuis
Figure 6.    Biogeographical  distribution  of the California grunion, Leuresthes tenuis.

-------
  1972). The premaxillary extends over the mandible. The first
  dorsal fin has 5-7 spines, second dorsal fin 1 spine and 9-10
  rays, and anal fin 1 spine plus 21-24 rays.

4. Collection handling, spawning and transport of embryos.

  a. Where - California grunion eggs are collected along
     beaches of southern California during natural spawning
     runs which occur from February through August, with a
     peak in spawning activity during April and May (Walker,
     1949).

  b. When - Runs occur at night and are timed just after the
     highest high tides during each semilunar cycle. Generally,
     the 1 to 4 day period just after new and full moons is best
     for collecting. Runs usually occur as the  high tide is
     receding (Walker, 1952).

  c. How - California grunion are collected by hand as they are
     stranded on the beach during natural runs. Use of nets is
     forbidden by the California Department of Conservation. A
     scientific collection permit  is required and is available
     from the Department of Conservation, Sacramento, CA.

  d. Spawning in the field.

     1. Refer to Figure 7 for a diagrammatic explanation of the
       following procedure.

     2. Eggs  - Twenty  to 25 females, captured just prior to
       natural spawning, should be stripped into a  20 cm
       diameter glass culture dish containing clean seawater
       (depth 1 to 2 cm) from the spawning locale.

     3. Milt - Five to 8 males are then stripped into a separate
       dish containing clean seawater. Water containing sperm
       is  then poured into the dish containing eggs and mixed
       by gently stirring. After 10 minutes, the fertilization
       water is carefully decanted from the culture dish which
       is  then  refilled with clean seawater. This  refill-rinse
       procedure should be repeated at least 2 additional times.

     4. Fertilized embryos —  Grunion embryos are carefully
       pipetted, using a 1.5 cm I.D. x 45 cm glass tube equipped
       with a rubber squeeze bulb, into all-glass or stainless
       steel vacuum bottles. Several thousand embryos may be
       transported  in  a  vacuum  bottle  containing
       approximately 500 ml of seawater from the collection
       site. Water temperatures along the California coast will
       usually range from 16 to 20°C during the height of the
       reproductive season and salinities are generally ^32 %<>
       (Middaugh et al., 1983). Note:  It is absolutely essential
                          25

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           9
     COLLECTION
     DURING
SPAWNING  RUN
         CLEAN
         WATER7"-
              ADULTS DIPPED
                   TO
              REMOVE SAND
              INTO 20cm dram.
              GLASS CULTURE DISH
                                                    HAND STRP SPERM
INTO A GLASS CULTURE
DISH- THEN ADD TO EGGS
                    CLEAN -
                     WATER
    EMBRYOS ARE
    BURIED IN CLEAN
    BEACH SAND
                                      ^^
                                      • ••*• " •]
                                  WATT 10-15 MM THEN
                                    RINSE THREE TMES
   TRANSPORT
    TO LAB

- CLUTCHES OF
 150-3OO EGGS
                                      WOE MOUTHED
                                     VACUUM BOTTLE
                                                    TRANSFER EMBRYOS
                                 GLASS
                                LINED OR
                                STAINLESS STEEL
AFTER 12-14 DAYS AT 25'C
EMBRYOS ARE REMOVED
FROM SAND  TRANSFER  TO
CULTURE DISH OF
SEAWATER
            LARVAE POURED
            INTO 80S GLASS
            AQUARIUM
                                  PARTIALLY FILLED
                                  WITH WATER
ACUTE TOXICITY
     TESTS
 WATER IS AGITATED
 BY  STIRRING
            DAYS I-14 FEED
            5000 ARTEMIA
            NAUPLII  /;
            TWCE DAILY
Figure?.     Diagrammatic  explanation  of  procedure for
              collecting, fertilizing, incubating and testing  of
              California grunion, Leuresthes tenuis, embryos.
                              26

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     that sand not be pipetted into the vacuum bottles with
     fertilized embryos.

  5. Sealed vacuum  bottles -- Embryos from the collection
     site should be transported to the laboratory in vacuum
     bottles. Borthwick et al. (1985)  and Goodman et al.
     (1985a) were able to successfully ship fertilized eggs
     from southern California to Florida in vacuum bottles.
     The transport time ranged from 24 to 36 hrs.

e. Embryo incubation in the laboratory.

  1. Upon arrival at the laboratory -- Embryos are pipetted
     into clean, dry  beach sand  (2.0 cm  deep) in a 20 cm
     diameter glass culture dish. Small depressions (1.0 cm
     deep) are formed at 3  or 4 equally spaced  locations
     within the  sand and 150 to 300 embryos  are  then
     pipetted into each of these shallow depressions.

  2. Embryos — Dry sand is used to cover the embryos so that
     they are buried 0.5 to 1.0 cm deep. Thirty ml of sea water
     (from the vacuum bottle) is then poured into the sand at
     each location where embryos  were buried. The culture
     dish is then covered to prevent evaporation and placed in
     an incubator at 25°C. This  incubation temperature is
     based upon field measurements taken at locations where
     grunion embryos incubate naturally, 19  to 32°C, x —
     25°C (Middaugh et al.,  1983). Moreover,  Hubbs (1965)
     reported that hatching only occurred between 14.8 and
     26.8°C. Similarly, Ehrlich and Karris (1971)  observed
     that grunion embryos hatched when maintained at 14.0
     to 28.5°C. Optimal hatching,  close to 100%, occurred
     between 16 and 27°C. Hubbs (1965) pointed out that
     embryos incubated at temperatures of 19°C  or above
     would be able to hatch on the next series of highest tides
     in nature (approximately 10 to 14 days after they were
     fertilized).

  3. After 12 to 14 days — Embryos are  carefully removed
     from the sand substrate with a stainless steel spatula or
     spoon.

  4. To initiate hatching -- Approximately 500 to  1000
     embryos and surrounding sand are placed in a 20 cm
     glass culture dish containing = 1.5 1 of 25°C, 28 to 35 %o
     salinity seawater. A spatula or a glass rod moved around
     the inner edge of the culture dish will create a circular
     current. This agitation of embryos and suspension of
     sand grains induces hatching.

  5. Hatched larvae - Should be  transferred to  160 1 (or
     larger) glass aquaria by pouring them from the 20 cm
     diameter hatching dish, or by using a  1.5 cm I.D. x 45 cm
                        27

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  glass pipette equipped with a rubber squeeze bulb. Care
  should be used to minimize the amount of sand and
  nonviable embryos transferred to the grow-out aquaria.

6. Density - The number of larval grunion in the grow-out
  aquaria should not exceed 10 I-1. A water temperature of
  25°C and salinities of 28 to 35 %o should be maintained
  (Borth wick etal., 1985).

  a. In a flow-through (dynamic)  system - The holding
     aquarium  (160  1) should  receive  20 1  hr-1 of
     temperature and salinity adjusted seawater.

  b. In a  recirculating (static) system  — The  holding
     aquarium (160 1) should be equipped with a Dyna-Flo
     Model 425  Aquarium Filter (or equivalent). This
     filtration  system  should be charged with spun
     polyester  aquarium  filter-fiber  and  activated
     charcoal. It is essential to cover the siphon intake
     with  300-400 mm  mesh plankton netting so that
     grunion  larvae are not  impinged on the syphons or
     pulled into the filtration unit. Units should be turned
     off between 0700-1600 hrs (during  the twice daily
     feedings). Filter media  should be changed  at least
     twice weekly and the syphon screens checked  and
     cleaned daily if necessary.

7. Feeding -  On the day of  hatching and  until  used in
  toxicity test,  grunion should be fed 5,000 Artemia
  nauplii  1-1, twice daily (i.e.,  0800 to 0900 and 1500 to
  1600 hrs).  For a 160 1 holding aquarium,  800,000
  Artemia nauplii should be added at each feeding.
                     28

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     III. Acute toxicity tests, M. beryllina, M. menidia,
                  M. peninsulae and L. tenuis

A.  Static tests (96 hours).

    1. Conducted - In 4 1 wide mouth glass jars containing 3 1 of
      filtered (5 um) seawater maintained at 25 ± 1°C and 0 to 35 %o
      salinity (depending upon the species used). It is convenient to
      utilize a  salinity  similar to that in  the  grow-out aquaria.
      Refer to Appendix G for recommended test conditions.

    2. Age of fish -- Fourteen day-old atherinids are recommended
      for testing. Because hatching of larvae is synchronous, all
      individuals should be of identical age.

    3. Transfer of larvae — Under no circumstances should larvae be
      dip-netted.  Mass  mortalities will occur. Transfer from the
      grow-out aquaria is accomplished by siphoning atherinids
      (use a 3.0 cm I.D. x 1.5 m long plastic tube) into a 12 to 15 1
      glass  or plastic container. Individuals are then pipetted (1.5
      cm x 45 cm glass pipette equipped with a rubber squeeze bulb)
      or dipped into a 200 ml  beaker. It is easy to enumerate 5
      larvae in each beaker. Volume is then reduced to 10 ml in the
      beakers and the contents are poured into test jars. A  squeeze
      bottle of  uncontaminated test media should be available  to
      wash larvae from beakers if they are stranded.
    4. General guidelines — Procedures provided by ASTM (1980)
      should serve as a guide in conducting acute toxicity tests with
      the atherinids, however, it is essential to feed all species with
      Artemia nauplii during 96 hr tests. Live Artemia (20  to  30
      nauplii per fish) are provided 2 to 3 times daily during
      exposure. This amount  of food should  provide minimal
      nutrition without confounding results  due to  dissolved
      oxygen or loading problems (Borthwick et al., 1985).

    5. The toxicant - If the chemical being tested results in rapid
      mortality of Artemia nauplii, it may be necessary to remove
      the dead  nauplii from the bottom of test containers  prior  to
      each  subsequent  feeding with live Artemia.  It  is also
      important not to over-feed if fish will  not eat  available
      Artemia.

    6. Test containers - No aeration should be required. Dissolved
      oxygen concentrations should  be  >60% of saturation.  A
                              29

-------
      photoperiod of 14L:10D with a light intensity of 11,000 lux is
      recommended.

   7. Temperatures and salinities utilized —  These variables
      should be similar to conditions in adult spawning and larval
      rearing tanks. The values summarized in Appendix G are
      recommended.

B. Flow-through tests (96 hours).

   1. Conducted in 601 glass aquaria supplied with =<20 to 60 1 hr1
      of 20 um filtered seawater.

      a. Toxicant metering system - Should be selected on the basis
        of the amount of toxicant to be metered, the flow rate of
        dilution water and the series of toxicant concentrations
        under consideration (ASTM, 1980; Clark et al., 1985).

      b. Toxicant carrier concentrations -- These concentrations
        should be constant for all exposures within a test.  A
        seawater control and carrier control should be maintained
        along with the 4 to 7 exposure concentrations of toxicant.

      c. To facilitate observations and enumerate mortalities —
        Fish may be confined to 4 1 wide-mouth glass jars with two
        screened (100 -140 mm mesh nylon screen) openings, 3 cm
        diameter, 1 cm above the base.

        1. Each 60 1 aquaria may contain 2 to 4 of the 4  1 wide
        mouth glass jars with 10 fish jar -l.

        2. A self-starting syphon (6  cm I.D. ) in the 60 1 aquarium
        provides a  10-15 cm draw-down of water approximately
        once every 15 min., thus ensuring adequate  water
        exchange between  the 4 1 holding jars  and larger 60 1
        aquaria.

        3. Other operational parameters are identical to those
        provided for static tests. Refer to section III. A. 2-7.
                             30

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IV. Early Life-stage toxicity tests, silversides, Menidia
           beryllina, M. menidia, and M. peninsulas.

A.  Seawater — Dilution water for this 28 day test should be passed
    through a sand filter and 20 um polypropylene filter. Water
    temperature should be continuously maintained at 25 ± 1°C for
    all three species.  Salinity should  be maintained at
    approximately 4 to 6 %o for M. beryllina (or at the collection site-
    laboratory spawning salinity if higher or lower) and 18 to 30 %o
    for M. menidia and M. peninsulae (Goodman et al., 1985b).

B.  Exposure system - A glass proportional diluter similar to that
    described by Schimmel et al., (1974) is used in each test. The
    diluter  delivers 1 1 of water to each control and  treatment at
    each  cycle (approximately every 15 min). Glass splitter  boxes
    equipped with two 2 mm I.D. glass capillary tubes slowly deliver
    the seawater from the diluter to each of the two exposure
    aquaria for each  treatment. A 4 mm  I.D. self-starting siphon
    varies the water depth in each glass aquarium (21 cm long by 22
    cm wide by 10 cm high) between approximately 4 and 7 cm. The
    draw-down time is 1.5 to 3.0 min and helps to ensure adequate
    exchange of toxicant between the exposure cups and aquarium.
    Exposure aquaria are partially immersed in a freshwater bath
    that maintains the respective tests at 25 ± 1°C. The photoperiod
    during all  testing  is  14L:10D  and  light  intensity is
    approximately 1400 lux.
    1. Embryos —The embryos of each species have numerous
      chorionic fibrils that must be gently teased apart and their
      fibrils clipped before selecting individuals to be used in the
      toxicity test. Embryos are examined microscopically; groups
      of  four or five  viable and synchronous individuals are then
      randomly placed in each incubation cup until the cup
      contains 16 embryos. Two incubation cups are then placed in
      each of the two duplicate aquaria for each of the seven
      treatments.

    2. Incubation cups ~ These containers should be constructed of
      glass petri dish bottoms (9 cm I.D.) with 10-cm-high cylinders
      of  363  pm nylon mesh attached to the inside walls with
      silicone adhesive. These cups are used in tests with all three
      species. At test initiation, embryos should be approximately
      32 to 36 hrs post-fertilization. If held at 25°C, these embryos
                             31

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  should be in stages  18 to 20 of development (Lagler et al.,
  1977).

3. Observations - Daily observations are made for deaths and
  signs of poisoning. Dead animals are removed and recorded
  when observed. Larvae are usually first observed on day 4 in
  tests with M. menidia and M. peninsulae and on day 5 in the
  M. beryllina test. Silverside larvae are fragile and susceptible
  to injury or stranding on the mesh  of incubation cups.
  Therefore, during intervals after  hatching  begins,  the
  incubation cups should not be removed from the exposure
  aquaria. Larvae are counted in place. Intervals are two days
  for M. menidia, five days for M. peninsulae, and ten days for
  M. beryllina. Before incubation cups  containing hatched fish
  are removed from the aquaria, the  water level should be
  lowered slowly to below the top of the  petri dish using a 4 mm
  (I.D.) glass siphon.

4. Feeding — Rotifers, Brachionus plicatilis', and  Artemia sp.
  nauplii (<8 hours old) are used as food for Menidia spp. Each
  M.  menidia incubation cup  is provided a  1:1 mixture of
  rotifers (2,500) and Artemia (2,500) twice daily (0800 to 0900
  and  1400 to 1500 hrs) for the first eight days after hatching
  begins, and thereafter, only Artemia (5,000) twice daily until
  test termination. Menidia peninsulae  and M. beryllina are fed
  rotifers three times (0800 to 0900, 1200 to 1300 and 1400 to
  1500 hrs) daily for the  first 8 days after hatching begins at a
  rate of 5,000 feeding-1 followed by a  three-day transition
  period in which both rotifers (2,500) and Artemia (2,500)  are
  provided in 3 feedings day1 and then  Artemia (5,000) 3 times
  day1 until test termination. In each test, equal portions of
  food are dispensed to all cups containing hatched fish except
  those with few survivors, which should received
  approximately one half as much if considerable food remains
  from previous feedings (Goodman  et al., 1985b). Fish are  not
  fed on the last day of the test.

5. Test completion — At termination  of the 28-day experiments,
  fish  are killed by immersion in ice water, drained  on paper
  towels, weighed individually, and may be combined within
  exposure concentrations and frozen for subsequent  chemical
  residue analysis.

6. Statistical  treatment — Analysis  of variance and Duncan's
  multiple range test may be used to analyze survival  and
  weight data. Individual fish weights are used in weight
  analyses. Percentages should  be arcsine  transformed; a
  minimum  significance level of a — 0.05 is  used for  all
  statistical purposes.
                          32

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        V. Early life-stage toxicity tests, L. tenuis

A. Seawater — Dilution water for this 35-day test should be passed
   through a sand filter and 20 um polypropylene filter. Water
   temperature should be continuously recorded and maintained at
   25 ± 1°C. Salinity should be maintained at 25 to 30 %o (Goodman
   etal.,1985a)

B. Exposure system — A glass proportional diluter similar to that
   described by  Schimmel et al., (1974) delivers 1.0 1 of water to
   each treatment at each cycle (approximately every  15 min).
   Glass splitter boxes equipped with two 2 mm I.D. glass capillary
   drains delivered the seawater from the diluter to the two glass
   exposure  aquaria per treatment. Exposure aquaria (I.D.  = 21
   cm long x 22 cm wide x  10 cm high) should be partially
   immersed in a freshwater  bath that will maintain test water
   temperature at 25 ± 1°C. During embryo exposure, the aquaria
   are equipped with a 5-mm I.D. self starting siphon  that
   fluctuates the water depth between 2 and 7 cm. The only carrier-
   solvent used successfully in California grunion ELS tests is
   triethylene glycol at a concentration of 0.4 pi I-1.  Attempted ELS
   tests at higher triethylene glycol concentrations failed because
   embryonic development in treatments receiving the carrier-
   solvent was  slower than in the  seawater-control treatment
   (Goodman et al., 1985a).
   1. Embryos — During the test, embryos should be immersed in
      seawater and kept in darkness prior to testing.  The test
      should be started within 48 hrs after embryos are fertilized.
      Embryos should be in developmental stages 22 to 24 (Lagler
      et al., 1977)  or younger. The  embryos are  examined
      microscopically and groups of four  viable specimens placed
      randomly in each of 28 or more incubation cups. This process
      is repeated until all cups contain 16  embryos. Treatment and
      duplicate numbers are assigned by  using a random number
      table. Two incubation cups are then  placed in each of the two
      duplicate aquaria per treatment except that at least two
      additional  cups should be placed  in the carrier-control
      treatment for hatching trials.

   2. Incubation cups -  Embryos are  maintained in  containers
      constructed by replacing the bottom of a 250-ml glass beaker
      with 450-mm nylon mesh secured with silicone adhesive. Two
      7.5 cm long glass tubes (8-mm I.D.)  attached horizontally on
                             33

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  opposite edges support the cup above the aquarium bottom.
  Embryos are incubated in darkness  until hatching is
  stimulated.  During this pre-hatch interval, a flashlight is
  used when taking water samples or checking viability of
  embryos. During the later stages of embryonic development
  care must be taken to prevent jostling the embryos because
  this could stimulate hatching.

3. On exposure day 9 -- (embryos -12 days old) Embryos from one
  of the extra cups in the carrier-control treatment should be
  gently rinsed into a larval incubation cup, constructed by
  attaching 9-cm-high cylinders of 450  pm nylon mesh to the
  inside walls of 100 x 15 mm glass Petri dish bottoms with
  silicone adhesive. The  embryos are placed on a laboratory
  shaker and then alternately shaken (approximately 68 cycles
  min-1) and  kept stationary for 2-min intervals  until  no
  additional fish hatch in two consecutive 2-min periods; two or
  three intervals of shaking are required. If a large percentage
  ( = 75%) of the embryos hatch readily, then hatch those in all
  treatments, but discard those from the extra carrier-control
  cup. If  a good hatch is not obtained from the first cup
  attempted, wait another day and try the second extra carrier-
  control cup. After removing cups with larvae from the shaker,
  dead embryos are removed, and after replacing the siphons in
  the aquaria with 2 mm I.D. siphons that vary the water depth
  from 5  to 7 cm, the incubation cups are placed in their
  respective aquaria. The photoperiod is changed from OL:24D
  to!2L:12D.

4. Fish - In this test are fed <24-hr-old Artemia nauplii twice
  daily, except for the last 24  hrs of the experiment when no
  food is provided. Equal volumes of a suspension of nauplii are
  dispensed to each incubation cup. The suspension should be
  sampled frequently and the number of Artemia in a volume
  equal to that dispensed per cup at each feeding should
  average 5,000 (Goodman et  al., 1985a).  Dead animals are
  removed and recorded daily, and qualitative observations of
  signs of poisoning are noted.

5. At termination of the experiment — Fish  are killed by
  immersion  in ice water, then drained on paper towels,
  individually weighed,  and  may be frozen for subsequent
  analysis. Survival and  growth data may be analyzed by one
  way analysis of variance. Percentage survival data should be
  arcsine  transformed before analyses. Treatment  means may
  be compared  by using Duncan's multiple-range test. A
  significance level of a=  0.05 is used for all analyses.
                          34

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     VI. Batch culture of the alga, Chlorella sp. and
         mixohaline rotifer, Brachionus plicatilis.
   A.  Apparatus used.
   1. Six to eight, 13 to 201 pyrex glass carboys and stoppers to fit.
   2. Four to six, 41 pyrex glass flasks with cotton plugs.
   3. High wattage thermostatically controlled immersion heater,
      Thelco-Thermajust Model 15094 1000W-110V or equivalent.
   4. Laboratory timer, up to 120 mins elapsed time and able to
      accomodate immersion heater of 1000W-110V capacity.
   5. Source of clean compressed air.
   6. Analytical balance-top loader.
   7. Microscope and hemacytometer.
   8. Automatic pipettor - 0.01 to 1.0 ml capacity, preferably with
      disposable tips.
   9. Plankton netting ~60 um mesh to collect rotifers.
   10. Tygon or equivalent tubing 3 and 10 mm I.D.
   11. Glass tubing 3 and 10 mm O.D.
B. Media preparation and Chlorella sp. culture.
   1. Refer to Figure 8  for a diagrammatic explanation of the
      following procedure.
   2. Clean carboys — Wash thoroughly with hot soapy water, rinse
      with  tapwater, then triple rinse with deionized or distilled
      water.
   3. Fill carboy -- Filtered (20 um) natural seawater, salinity 25 to
      30 %o should be used. If an artificial seawater mix is used, the
      reconstituted media should be  handled  according  to
      manufacturer's instructions and allowed to age for at least 7
      days prior to pasteurization. The carboy is filled to the top lip.
   4. Immersion  heater -- Should be placed in carboy  with
      thermostat set at 70 to 80°C. Heater power supply is always
      routed through an automatic timer as a safety precaution.
                             35

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 o
AERATION
n IMMERSION
 HEATER
  HEAT WATER TO 70-80°C
  FOR I HOUR
                                12-14 HOURS
                        STOPPER TO
     INSTALL  STOPPER    FIT CARBOY
                                               ADO
                                           TRACE METALS
                                           PHOSPHATE + NITRATE
                                           VITAMIN MIX
                                           FERRIC CHLORIDE
                                    VENT
       PROVIDE MODERATE
         AERATION
                           AFTER 5 TO 7 DAYS
                           CHLORELLA  CELL DENSITY
                           2 TO 3X107/1	THEN
                                            ADD BRACHIONUS
                                                           AFTER 5 T07 DAYS
                                                           BRACHIONUS DENSITY
                                                           	,000/1
  PROVIDE CONSTANT
  ILLUMINATION, II.OOOLUX
  AND MODERATE AERATION
                       PROVIDE  GENTLE
                         AERATION
                              FEED  TO
                              LARVAL MENIDIA
 Figure 8.     Diagrammatic explanation of procedure for culturing
                the mixohaline rotifer, Brachionus plicatilis.
                                  36

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5.   Seawater --  Should be heated to a thermostatically  set
    temperature  of ~70 to 80°C. This temperature should be
    maintained for 1 hr. A glass tube (3 mm O.D.) inserted into
    the carboy (before heating begins) and attached to an  air
    line provides moderate aeration/circulation of the water
    during the pasteurization process. This aeration/circulation
    is essential to ensure even heating of media and to prevent a
    thermocline from forming in the carboy.

6. After maintaining ~70 to 80°C  for 1 hr  -- Turn off the
  immersion heater, let it cool down for 5 mins, then remove it.
  The automatic timer system can be set to the proper elapsed
  time to accomplish heat-up, pasteurization and cool-down on
  an automatic  basis after heating dynamics of the carboy-
  immersion heater system are determined on the first few
  carboys of seawater. Note: If a large autoclave is available it
  may be used to sterilize culture media thus avoiding the
  procedures outlined above in B. 4-6.

7. Gentle aeration ~ Should be maintained for 12 to 14 hrs until
  the seawater has cooled to ambient temperature. The carboy
  should then be moved to a convenient location where high
  intensity lighting (> 11,000 lux) is continuously provided.

8. The aeration tube-siphon tube-vent system - This is wrapped
  in clean aluminum foil and maintained in a drying oven at ~50
  to 60°C, it is then  removed from the oven and installed in the
  carboy of pasteurized seawater.

9. Appropriate  enrichment  media  — To grow Chlorella,
  nutrients are then added to the carboy and allowed to mix for
  5 mins. Enrichment media will differ according to the type of
  seawater used, natural or  artificial, and the locale where
  collected. One media enrichment formulation is  summarized
  in Appendix H. This formulation may need to be modified for
  optimal growth of Chlorella sp. under local  conditions.
  Additional formulations  are available  in Walsh and
  Alexander (1980), Theilacker and McMaster (1971) and the
  American  Public Health Association, Standard Methods
  (1985).

10.  Moderate aeration —  Should be provided to mix nutrients
    and to keep Chlorella sp. cells in suspension.

11.  Carboy - It  should then be inoculated with 4 to 5 x 105
    Chlorella sp. cells.

12.  Chlorella sp. cells - They should be allowed to grow for 5 to 7
    days depending  upon the initial density  of starter cells
    added to the 13 to 201 carboy.

  a. 5 ml samples of Chlorella sp. should be removed and cell
     density determined  using  the hemacytometer  until the
                          37

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        culture becomes a bright green and contains 2 to 3 x 107
        cells I-1. We generally take replicate 5 ml samples from the
        carboy and make 4 to 8 counts per sample to determine cell
        density.

C. Culture of B. plicatllis.

   1. Starter cultures -- Brachionus plicatllis cultures  are
      maintained in static 4 1 glass flasks containing 2 to 3  1 of
      Chlorella sp. with an initial cells density of 2-3 x 107 cells I-1.

   2. Cultures -- Should be renewed at 7 to 10  day intervals by
      innoculation  of new pasteurized (sterilized) and nutrient
      enriched culture media with Chlorella sp. When Chlorella sp.
      cell densities grow  to 2 to 3  x 107 cells 1-1, Brachionus is
      added.

      a. To determine Brachionus densities — The 4 1 glass flask is
        shaken to ensure an even distribution of Brachionus. The
        density of Brachionus may be determined by pouring 1 1 of
        the media from the flask through ~60 mm plankton netting.
        This sample is then washed into a 100 ml beaker (using a
        squeeze  bottle containing pasteurized seawater) and
        pasteurized water is then added to the beaker to bring the
        volume  to 20,  50  or 100 ml, depending  upon  the
        concentration of Brachionus present.

      b. Five, 10 pi subsamples are  then removed from the 100 ml
        beaker. Each sample is placed in a deep well depression
        slide or in  the center of a clear glass crystallization dish.
        One drop of a 10% neutral buffered formalin solution is
        then added to each 10 ul sample of Brachionus.

      c. Counts of Brachionus - Should be conducted at 15 to 30x
        magnification using a dissecting microscope, and the mean
        number of Brachionus determined for the five samples.

      d. Back calculate - The number of Brachionus 100 ml-1 (or to
        50 or 20 ml of concentrate) is calculated from the original 1
        1 sample.

        1. For example in five samples the x number of Brachionus
           = 80 per 10 pi x 100 = 8000 ml-l

           8000 ml-l x 100 ml = 800,000 H
           8000 ml-l x 50 ml = 400,000 H
           8000 ml-l x 20 ml = 160,000 1-1

      e. Use 10,000 to 20,000 Brachionus I-1 to innoculate each 13
        to 20 1 carboy of Chlorella sp. when the alga cell density has
        reached 2 to 3 x 107 cells H.

   3. Brachionus densities -- The densities should reach 150,000 to
      300,000 H by the 5th to 7th day after a carboy is innoculated.
                              38

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  The procedure explained in VI. C. 2. a. through e. is used to
  quantify Brachionus in carboys.

  a. When densities are > 200,000  I-1 we recommend that the
     entire volume of the carboy be used over a 4 to 5 day period.

     1. Daily use of 2 to 3 1 of Brachionus is recommended.

     2. Daily counts of Brachionus I-1 are required to maintain a
       record so that feeding rates can be adjusted (by dilution
       or concentration of 1  1 samples). Recall that a feeding
       rate of 10,000 Brachionus I-1 volume of holding aquaria
       for Menidia sp. is recommended.

Caution:

4. Brachionus is not capable of synthesizing essential fatty acids
  (EFA's) for marine fish in the quantities required by  those
  fish (Lubzens et al., 1985). The rotifers must therefore be fed
  on algae that contain high levels of EFA's for marine fish
  (e.g., Skeletonema, Tetraselmis, Chaetoceros, Isochrysis, or
  marine Chlorella, but not Dunaliella or Phaeodactylum).
                           39

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       VII. Hatching of brine shrimp, Anemia sp.

A. Chemical analyses-The strain of Artemia used should be
   analyzed for chemical  residues  including heavy metals and
   pesticides.

B. Apparatus required.

   1. Four to six, 2 1 separatory funnels.

   2. Several 500 ml beakers.

C. Hatching procedure.

   1. Fill -- A 2 1 separatory funnel with approximately 1,800 ml of
      20 urn filtered seawater or reconstituted artificial seawater
      that has been aged for at least 7 days. The salinity should be
      adjusted to 25 to 30 %o.

   2. Add —  Artemia cysts, 15  to  20 ml (dry  measure) to the
      separatory funnel.

   3. After adding Artemia cysts — Clean air is vigorously bubbled
      through a 1-ml pipette which is lowered through the neck of
      the funnel until the tip rests on the bottom. Aeration keeps
      the cysts and newly hatched Artemia nauplii in suspension.
      Cysts should hatch in 24 to 36 hrs when the temperature is
      27°C.

   4. After 24 hrs - The pipette supplying air is removed.  Allow
      Artemia nauplii to settle to the bottom of the separatory
      funnel.  A light source placed near  the bottom of the
      separatory funnel will enhance the settling process. Empty
      cysts will rise to the surface.

   5. After approximately five mins, using the stopcock, collect the
      nauplii into a 500 ml beaker  with a 100 mm mesh screen
      bottom. Discard the hatching water and rinse the nauplii into
      a 500 ml beaker.

   6. After another five mins,  again collect the nauplii  and rinse
      into the beaker.

   7. The nauplii are further  concentrated by  pouring the
      suspension into  a small cylinder which has one end  closed
      with 100 mm plankton netting.
                             40

-------
   8. The concentrate  is resuspended in  50 ml of appropriate
      culture water, mixed well, and dispensed with a pipette.

   9. Discard the remaining contents of the hatching vessel, wash
      the vessel with hot soapy water, and rinse thoroughly.

   10. Prepare fresh seawater for each new batch culture  of
       Artemia nauplii.

   11. To have a fresh supply of Artemia  nauplii daily, several
       hatching vessels must be set up and harvested on alternate
       days.

D. Enumeration of Artemia nauplii.

   1. Suspensions of nauplii should be well mixed.

      a. draw off five 1.0 ml aliquots of the suspension.

      b. the Artemia nauplii in each 1.0 aliquot may then be slowly
        pipetted onto white filter paper so that the 1.0 ml volume is
        dispersed over a wide area of the paper.

      c. Artemia nauplii are then enumerated by placing the filter
        paper  on a dissecting microscope.  The mean number  of
        nauplii in five samples is then used in back calculations to
        determine the volume of original suspension to be fed  to
        Menidia sp. or Leuresthes tenuis. Recall that a feeding rate
        of 5,000 Artemia nauplii I-1 volume of holding aquaria is
        recommended.

   E. Nutritional quality of Artemia.

   1. To the extent that the atherinid species discussed here are
      marine, they require a marine diet. Marine and freshwater
      fish have different nutritional requirements, especially with
      regard to essential fatty acids. Watanabe et al., (1978) pointed
      out that Artemia can be divided in two categories, those that
      are adequate for marine organisms and those that are not,
      based on  their  fatty acid composition. Different geographical
      strains of Artemia  vary in their nutritional quality for
      Menidia (Beck et al., 1980; Beck  and Bengtson, 1982) and a
      single geographical strain  can also vary over time (Leger  et
      al., in press).
                              41

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                  VIII. REFERENCES

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Bengtson, D.A. 1984. Resource partitioning by Menidia menidia and
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Cook, S.F. and R.L.  Moore. 1970.  Mississippi silverside, Menidia
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                              44

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Goodman, L.R., D.J. Hansen, D.P. Middaugh, G.M. Cripe and J.C.
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Leger, P., D.A. Bengtson, K.L. Simpson and P. Sorgeloos. In press.
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                              46

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Atherinidae) with notes on  survival and growth  of larvae  at
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                              47

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44:1115-1121.
                              48

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Appendix A
Selected biogeographical data for occurrence of the
            inland silverside, Menidia beryllina
State
Locale
                                   Habitat
Rhode Island
Rhode Island
Massachusetts
Massachusetts
Connecticut
Connecticut
Delaware
Virginia
Virginia
Virginia

North Carolina
North Carolina
North Carolina
North Carolina
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Alabama
Mississippi
Mississippi
Louisiana
Louisiana
Louisiana
Louisiana

Louisiana
Louisiana
Arkansas
Tennessee
Kentucky
Illinois
Texas
Texas
Texas
Texas
Texas
Texas
Texas
Oklahoma
Oklahoma
Oklahoma
Oklahoma
California
California
California
Pattaquamscutt R.
Point Judith Pond
Massachusetts Bay
Quincy Bay
Mystic R. (lower)
Mill R.
Delaware R. (lower)
Potomoc R. (lower)
James R.
Rappahannock R.
(45 mi upstream)
Pasquotank R.
Edenton Bay
Perquiman's R.
Neuse R.
Palatka
L. Eustis
L. Weir
St. Johns R.
South Lake
L. Monroe
L. Jessup
Escambia Bay
Blackwater Bay
Perdido Bay
Gulf Shores
Escatawpa R.
Moon Lake
L. Pontchartrain
L. Angola
Wax Lake
Mississippi Delta

Chandeleur Islands
L. St. John
L. Chicot
Reelfoot Lake
Hamby Pond
Mississippi R.
L. Marble Falls
L. Buchanan
L. Inks
L. Brownwood
L. Texoma
Colorado R.
Laguna Madre
L. Texoma
Keystone Reservoir
Arkansas R.
Boomer Lake
Clear Lake
Sacramento River
Lexington Reservoir
Estuarine
Estuarine
Estuarine
Estuarine
Estuarine
Estuarine
Estuarine
Estuarine
Estuarine
Riverine

Estuarine
Estuarine
Estuarine
Estuarine
Lake
Lake
Lake
Riverine
Lake
Lake
Lake
Estuarine
Estuarine
Estuarine
Estuarine
Riverine
Lake
Estuarine
Lake
Lake
Riverine/
Estuarine
Estuarine
Lake
Lake
Lake
Pond
Riverine
Lake
Lake
Lake
Lake
Lake
Riverine
Estuarine
Lake
Lake
Riverine
Lake
Lake
Riverine
Lake
Citation

Bengtson, 1984
Bengtson, 1984
Kendall, 1902
Robbing, 1969
Pearcy and Richards, 1962
Johnson, 1975
DeSylvaetal.,1962
Kendall, 1902
Raney,1950
Massman, 1954

Smith, 1893
Smith, 1893
Johnson, 1975
Tagatz and Dudley, 1961
Johnson, 1975
Chernoffetal., 1981
Chernoffetal.,1981
Chernoffetal., 1981
Kendall, 1902
Kendall, 1902
Kendall, 1902
Chernoffetal.,1981
Middaughetal., 1986
Chernoffetal.,1981
Johnson, 1975
Chernoffetal.,1981
Chernoffetal.,1981
Chernoffetal.,1981
Chernoffetal.,1981
Chernoffetal.,1981
Chernoffetal.,1981

Chernoffetal.,1981
Johnson, 1975
Chernoffetal.,1981
Johnson, 1975
Sisk.1973
Smith, 1979
Tilton and White, 1964
Tilton and White, 1964
Tilton and White, 1964
Tilton and White, 1964
Mense, 1967
Tilton and White, 1964
Simmons, 1957
Hubbs, 1982
Gomez and Lindsay, 1972
Gomez and Lindsay, 1972
Sisk and Stephens, 1964
Cook and Moore, 1970
Moyleetal., 1974
Moyleetal., 1974
                                 49

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                         Appendix B
     Recommended environmental variables and
  feeding regimes for laboratory spawning of three
                      atherinid fishes
Environmental
  Variable

Adult holding/spawning

Photoperiod          13L:11D
Intensity (lux)
    175-300
Tidal signals/
interrupted
current velocity
Salinity (%«)
Water Temp. (°C)
none required
0-5
25
Food required

Tetramin Flakes
Artemia sp.
nauplii (optional)
ca. 150,000 I1
8 gat0800-0900 hr
4gat 1000-1100 hr
4 g at 1300-1400 hr
8 g at 1500-1700 hr


 1 liter all 130 hr
                  Atherinid species
                    M. menidia
    13L:11D

    175-300


  1200-1300 hrs
  2400-0100 hrs

     25-30

   22 (N. lat.)
   25(S.lat.)
8gat0800-0900 hr
4gat 1000-1100 hr
4 g at 1300-1400 hr
8 g at 1500-1700 hr


 1 liter all 130 hr
  M. peninsulae



    13L:11D

    175-300


  1200-1300 hrs
  2400-0100 hrs

     25-30

      25
8 gat 0800-0900 hr
4gatlOOO-1100hr
4g at 1300-1400 hr
8gatl500-1700hr


 1 liter all 130 hr
                              50

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                         Appendix C
     Recommended environmental variables and
   feeding regimes for laboratory incubation and
         larval rearing of four atherinid fishes
Environmental
  Variable
                Atherinid species
             M. menidia   M. pemnsulae    L. tenuis
Embryo-larval rearing

Photoperiod      14L:10D

Intensity (lux)     11,000

Salinity (%.)        0-15

Water Temp. (°C)    25
Larval density I'1
(grow-out tanks)

Food required

Brachionus sp.

amount 1 '
vol. of
grow-out tanks
    5-10
  days 1-5

 10,000 twice
   a day
  14L:10D

   11,000

   25-30

 22 (N. lat.)
 25(S.lat.)

   5-10
  days 1-5

 10,000 twice
   a day
 14L:10D

  11,000

  25-30

    25


   5-10
 days 1-5

10,000 twice
  a day
  14L:10D

  11,000

  2530

    25


   5-10
not required

not required
Artemia sp.


amount H
vol. of
grow-out tanks
day 6 through
end of holding

 5,000 twice
   a day
day 6 through  day 6 through day 1 through
end of holding  end of holding end of holding
 5,000 twice
   a day
5,000 twice
  a day
5,000 twice
   a day
                               51

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                            Appendix D
Selected biogepgraphical data for occurrence of the
            Atlantic silverside, Menidia menidia
State

Maine
Maine
Maine
Maine
Rhode Island
Rhode Island
Rhode Island
Massachusetts

Massachusetts
Massachusetts
Massachusetts
Massachusetts
Massachusetts
Massachusetts
Massachusetts
Massachusetts
Massachusetts
Connecticut
Connecticut
New York
Delaware
Virginia
Virginia
Virginia
Virginia
Maryland
Maryland
Maryland
Maryland
North Carolina
North Carolina
North Carolina
South Carolina
South Carolina
South Carolina
South Carolina
South Carolina
South Carolina
Georgia
Georgia
Georgia
Georgia
Georgia
Florida
Florida
Florida
Florida
Florida
Locale

S. Portland
Scarborough Harbor
Todd Point
Casco Bay
Point Judith Pond
Pettaquamscutt R.
Bissell Cove
Massachusetts Bay

Vineyard Sound
Buzzard Bay
Nantucket Sound
Eel Pond
Great Harbor
Hadley Harbor
Katama Bay
Woods Hole
Salem Harbor
Noank
Pataguanset R.
Fire Island Inlet
Delaware R. (lower)
James R.
Rappahannock R.
Pamunkey R.
Oyster
Solomons Island
Drew Point
Green Holly Creek
Molly's Island
Moorehead City
River's  Island
Neuse River (lower)
Cape Romain
Magnolia Beach
Cape Island
North Edisto R.
Edisto R. (lower)
Battery Island
Sea Island
Ogeechee R.
Sapelo Island
St. Simons Island
Jekyl Island
Ft. George Inlet
Malangos R.
Flagler Beach
New Smyrna Beach
Mosquito  Lagoon
Habitat     Citation

Estuarine    Johnson, 1975
Estuarine    Robbins, 1969
Estuarine    Robbins, 1969
Estuarine    Kendall, 1902
Estuarine    Bengtson, 1984
Estuarine    Bengtson, 1982
Estuarine    Bengtson, 1982
Estuarine    Bigelow and Schroeder,
            1953
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Kendall, 1902
Estuarine    Conover and Kynard, 1984
Estuarine    Johnson, 1975
Estuarine    Cadigan and Fell, 1985
Estuarine    Briggs, 1975
Estuarine    DeSylva et al., 1962
Estuarine    Massman, 1954
Estuarine    Massman, 1954
Estuarine    Massman, 1954
Estuarine    Johnson, 1975
Estuarine    Bayliff, 1950
Estuarine    Bayliff, 1950
Estuarine    Bayliff, 1950
Estuarine    Bayliff, 1950
Estuarine    Kendall, 1902
Estuarine    Hildebrand, 1922
Estuarine    Tagatz and Dudley, 1961
Estuarine    Fowler, 1945
Estuarine    Fowler, 1945
Estuarine    Fowler, 1945
Estuarine    Middaugh, 1981
Estuarine    Fowler, 1945
Estuarine    Johnson, 1975
Estuarine    Fowler, 1945
Estuarine    Fowler, 1945
Estuarine    Fowler, 1945
Estuarine    Robbins, 1969
Estuarine    Robbins, 1969
Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Gosline, 1948
                                   52

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                          Appendix E
Selected biogeographical data for occurrence of the
         tidewater silverside, Menidia peninsulae
State

Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida

Florida
Mississippi
Mississippi
Texas
Texas
Texas
Texas
Locale

Melbourne
Ft. Meyers
Shell Point
Southport
Pass-A-Grille
Mosquito Lagoon
Crystal R.
Cedar Key
Santa Rosa Island

Escambia Bay
Pascagoula
Horn Island
Galveston Bay
Aransas Pass
Leffy Ann
Capano Bay
Habitat      Citation

Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Johnson, 1975
Estuarine    Chernoffet al., 1981
Estuarine    Chernoffet al., 1981
Estuarine    Chernoffet al., 1981
Estuarine    ChernofTet al., 1981
Estuarine    Middaugh and Hemmer,
            1984
Estuarine    Johnson, 1975
Estuarine    Chernoff etal., 1981
Estuarine    Chernoff etal., 1981
Estuarine    Johnson, 1975
Estuarine    Chernoff etal., 1981
Estuarine    Chernoffet al., 1981
Estuarine    Johnson, 1975
                                 53

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                        Appendix F
Selected biogeographical data for occurrence of the
          California grunion, Leuresthes tennis
State

California

California
California
California
California
California
California
California
California
California
California
California
California
California
California
California
California
California
California
Locale
Morrow Bay to
Cayucos
Ismo Beach
Santa Barbara
Malibu
Santa Monica
Venice
Hermosa Beach
Cabrillo Beach
Long Beach
Belmont
Huntington Beach
Newport Beach
Corona del Mar
Doheny Beach
Del Mar
Black's Beach
La Jolla
Mission Beach
Coronado Strand
Habitat
Beach

Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Beach
Citation
Walker, 1952

Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
Walker, 1952
                               54

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                     Appendix G
Recommended test parameters and feeding regimes
  for conducting static or flow-through 96 hr acute
    toxicity tests with 14 day-old atherinid fishes
Environmental
Variable M. beryllina
Photoperiod
Intensity (lux)
Salinity (%,)
Water Temp. (°C)
UL:10D
11,000
0-15
25
Atherinid species
M. menidia M. pemnsulae
14L:10D
11,000
25-30
22 (N. lat.)
25 (S. lat.)
14L:10D
11,000
25-30
25
L. tenuis
14L:10D
11,000
25-30
25
Feeding Requirements
Artemiasp
nauplii
20-30 fish -i
2 to 3 times
  daily
20-30 fish -i
2 to 3 times
  daily
20-30 fish i
2 to 3 times
  daily
20-30 fish i
2 to 3 times
  daily
                          55

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                         Appendix H

    Enrichment media for seawater used to grow
                         Chlorella sp.


Nutrient Mixes                                            Amount

TRACE METALS"

MnCl2-4H2O                                               361 mg
ZnCl2                                                      42 mg
CuSO4-5H2O                                                8 mg
Na2MoO4-2H2O                                              5 mg
CoCl2-6H2O                                                 8 mg
Glass distilled or deionized water                               1.0 liter

IRON>>

FeCl-6H2O                                                 480 mg
Glass distilled or deionized water                                100 ml

NITRATES AND PHOSPHATES "

NaNO3                                                    75 mg
NaH2PO4                                                   6 mg
Glass distilled or deionized water                               1.0 liter

Vitamin mix d

Thiamine hydrochloride                                       0.4 g
Biotin                                                     1.0 mg
B12                                                      1.0 mg
Glass distilled or deionized water                               1.0 liter

a add 1.0 mil' of seawater media
b add 0.1 ml 1 -1 of seawater media
c add 1.0 ml 1 ' of seawater media
d add 1.0 ml I ' of seawater media
                                56

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