United States
Environmental Protection
Agency
Office of Water
(4504F)
EPA842-F-98-003N
November 1998
<>EPA
Demonstrating Practical Tools for Watershed
Management Through the National Estuary Program
1 Characteristics:
The Coastal Bend Bays & Estuaries Program
(formerly the Corpus Christi Bay National
Estuary Program) encompasses three of
Texas' seven major estuaries and a wide
variety of highly productive habitats, includ-
ing oyster reefs, seagrass meadows, open bay
bottoms, coastal marshes, wind tidal flats,
barrier islands, and freshwater marshes.
Shrimp (Penaeus sp.)-are considered the most
important commercial seafood product in
Texas, accounting for over 90 percent by
dollar value and approximately 80 percent by
weight of all seafood landed each year.
Commercial shrimp represented 60 - 90
percent (by weight) of total seafood harvest
in the Coastal Bend from 1988 to 1993.
The Aransas Pass-Rockport Harbor is ranked
among the nation's top ten most valuable
fishing ports.
Bycatch is defined as the catch of organisms
in shrimp trawls other than the targeted
shrimp species.
Legend
)E-_—;~-- .:-_. fl San Antonio - Nueces Coastal Basin
| | Nueces River Basin
| | Nueces - Rio Grande Coastal Basin
m i stuaries and other coastal and marine waters are
i~i national resources that are increasingly threatened
M J by pollution, habitat loss, coastal development, and
resource conflicts. Congress established the National Estuary
Program (NEP) in 1987 to provide a greater focus for coastal
protection and to demonstrate practical, innovative ap-
proaches for protecting estuaries and their living resources.
As part of this demonstration role, the NEP offers funding for
member estuaries to design and implement Action Plan
Demonstration Projects that demonstrate innovative ap-
proaches to address priority problem areas, show improve-
ments that can be achieved on a small scale, and help deter-
mine the time and resources needed to apply similar ap-
proaches basinwide.
The NEP is managed by the U.S. Environmental Protection
Agency (EPA). It currently includes 28 estuaries: Albemarle-
Pamlico Sounds, NC; Barataria-Terrebonne Estuarine Com-
plex, LA; Barnegat Bay, NJ; Buzzards Bay, MA; Casco Bay,
. ME; Charlotte Harbor, PL; Columbia River, OR and WA;
Corpus Christi Bay, TX; Delaware Estuary, DE, NJ, and PA;
Delaware Inland Bays; DE; Galveston Bay, TX; Indian River
Lagoon, FL; Long Island Sound, CT and NY; Maryland
Coastal Bays, MD; Massachusetts Bays; MA; Mobile Bay, AL;
Morro Bay, CA; Narragansett Bay, RI; New Hampshire
Estuaries, NH; New York-New Jersey Harbor, NY andNJ;
Peconic Bay, NY; Puget Sound, WA; San Francisco Bay-Delta
Estuary, CA; San Juan Bay, PR; Santa Monica Bay, CA;
Sarasota Bay, FL; Tampa Bay, FL; and Tillamook Bay, OR.
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Worldwide fisheries stocks are being depleted and many
fisheries operations presently use harvesting equipment that
does not discriminate betweeen species. Shrimp trawl bycatch
(species caught incidental of the species meant for harvest) in
Coastal Bend bay waters is between 1.5 to 7 tunes the weight
of shrimp harvested. A recent study suggests that populations
of important commercial and recreational species are in decline
within the Coastal Bend bays, including Atlantic croaker,
southern flounder, gulf menhaden and adult blue crab. Pres-
ently there are no regulations for any gulf state mandated use
of bycatch reduction devices (BRDs) in state territorial waters.
However, concerns regarding finfish mortality associated with
shrimp trawling prompted a 1990 amendment to the Magnuson
Fishery Conservation and Management Act that mandated the
development of a Bycatch Reduction Research Program.
9EO53I1SE!
The purpose of the Bycatch Reduction Device Demonstration
Project was to evaluate, for the first time in Texas coastal bays,
the effectiveness of three BRDs. The project was designed to
compare trawls with and without BRDs to determine bycatch
reduction and shrimp retention rates.
The Coastal Bend Bays & Estuaries Program (CBBEP) lies
along the south central Texas Gulf coast in a semi-arid to
subtropical climate. The Program's project area includes three
of the seven major estuaries along the Texas coast. Among the
major riverine systems that flow into the estuaries are the
Mission, Aransas and Nueces Rivers. The composition and
distribution of the habitats and biota of the Coastal Bend are
greatly influenced by climate and their geographic setting.
Relatively healthy estuarine waters support a productive
ecosystem and diverse economy. Bay related activities
generate a total annual output in the region of $4.1 billion,
provide 53,068 jobs (about 1/3
of the employment in the area),
and generate a personal income
of $1.3 billion. Bay and gulf
commercial fisheries directly
benefit from a productive bay
system, and together generate
$45 million annually in total
output in the region.
The number of licensed shrimp
boats in the Coastal Bend has
decreased steadily since 1985,
however, statewide effort, or
number of days fished, has
increased 400 percent since
1961. The average shrimp
caught per unit of effort has
decreased in size by 40 percent
between 1972 and 1993. During the same period, an increase
in bay shrimp landings has occurred. In general, shrimpers are
fishing for longer periods to catch smaller shrimp of less
value.
A multi-partnership approach was taken in developing a
project to evaluate the effectiveness of three BRDs. The
partners included the Texas Seafood Producers Association,
Texas Parks and Wildlife Department, and Texas Sea Grant
College. Collectively, the group designed the project to allow
for comparisons between trawls with and without BRDs to
determine bycatch reduction and shrimp retention rates. All
partners were involved in gear selection, placement and
sampling methodology design.
At the request of the shrimping industry, the CBBEP Manage-
ment Committee approved funding for a demonstration
project to evaluate the effectiveness of three BRDs, 1) large
mesh extended funnel (LMEF), 2) a two-inch space bar turtle
exclusion device (TED); and 3) a fish eye, which is a trawl
with an escape hole for fish to exit. Paired-trawl sampling in
Coastal Bend bay waters facilitated comparisons between
BRDs and conventional trawls to determine bycatch reduction
and shrimp retention rates. Sampling commenced in spring
1997 and concluded after the fall bay shrimp season the same
year.
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Twenty comparative trawl tows were conducted with each
BRD during the 1997 spring and fall commercial bay-shrimp
seasons. Two trawls, one with a BRD and one without were
towed simultaneously. For each trawl, samples were separated
into shrimp and bycatch then weighed separately aboard the
vessel. A 25-pound subsample was collected from each tow,
separated into species groups, weighed, and counted.
The LMEF had the highest total bycatch reduction rates by
weight and second highest by number, with no significant
overall shrimp loss in spring. In addition, the LMEF reduced
the most abundant bycatch species, spot (Leiostomus
xanthurus), during spring and fall and the blue crab
(Callinectes sapidus) in the spring. Both Atlantic croaker and
sand seatrout were also greatly reduced in the fall with the
LMEF.
to reduce bycatch while limiting shrimp loss. Overall, the
LMEF significantly reduced bycatch more effectively by
weight and number than the other two BRDs during both
spring and fall.
Door
The two-inch space bar TED was first in total bycatch reduc-
tion by number during spring, but had significant shrimp loss
by weight resulting in greater shrimp loss than total bycatch
reduction. The two-inch space bar TED also had the greatest
reduction rates for sand seatrout (Cynoscion arenarius) in the
spring.
Results of the fish eye BRD varied among groups but showed
greatest reduction rates for Atlantic croaker and southern
flounder (Paralichthys lethostigmd) in the spring.
Success Stories
Results from the project varied between seasons and among
BRDs, but there are indications that BRDs have the potential
More importantly, this project
thawed relations between
historical adversaries in the
shrimp resource management
arena, namely shrimpers and
shrimp regulators. Hailed by
both sides as a step in the right
direction, the project-fostered
partnerships are the founda-
tion for continued pursuit of
common goals in an atmo-
sphere of mutual trust.
The CBBEP will continue to
promote this type of activity to
increase the lines of communi-
cation and to further enhance
our knowledge of bycatch-
related issues.
There are many factors involved in determining which BRDs
function more effectively than others. Some factors include
trawl mesh size and type, length of trawl bag, BRD type, size,
and placement along trawl, tow speed and duration, shrimp
size, bycatch composition, wrack type, variations in bottom
substrate, and water depth. Therefore, the need to continue
refining the sampling gear and methodology to evaluate
additional alternatives for bycatch reduction are necessary in
order to maintain this highly productive commercial fishery.
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Printed on Recycled Paper
IB|i|ii|||i||||!|i||||||||||||||i|||ii||||i|!||n|i||i||p
Report Title National Estuary Program
Biological Nutrient Removal Project Long Island Sound, CT/NY
Buttermilk Bay Coliform Control Project Buzzards Bay, MA
Georgetown Stormwater Management Project Delaware Inland Bays, DE
Texas Coastal Preserves Project Galveston Bays, TX
Shell Creek Stormwater Diversion Project Puget Sound, WA
City Island Habitat Restoration Project Sarasota Bay, FL
Buzzards Bay "Sep Track" Initiative Buzzards Bay, MA
New Options for Dredging in Barataria-Terrebonne Barataria-Terrebonne Basin, LA
Coquina Bay Walk at Leffis Key Sarasota Bay, FL
"Pilot Project Goes Airborne" Narragansett Bay, RI
The National Estuary Program: A Ten- Year Perspective General NEP Discussion
Rock Barbs in Oregon's Tillamook Bay Watershed Tillamook Bay, Oregon
The Weeks Bay Shoreline & Habitat Restoration Project Mobile Bay, AL
For copies of any of these publications contact:
National Clearinghouse for Environmental Publications
Telephone: (513) 489-8190
Facsimile: (513) 489-8695
iijiaiiii|i»iiiBiiiiiii!iiiii
Date
1995
1995
1995
1995
1995
1995
1997
1997
1997
1997
1998
1998
1998
Publication #
EPA842-F-95-001A
EPA842-F-95-001B
EPA842-F-95-001C
EPA842-F-95-001D
EPA842-F-95-001E
EPA842-F-95-001F
EPA842-F-97-002G
EPA842-F-97-002H
EPA842-F-97-002I
EPA842-F-97-002J «
EPA842-F-98-003K
EPA842-F-98-003L
EPA842-F-98-003M
v>EPA
United States
Environmental Protection Agency
(4504F)
Washington, DC 20460
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