Commentary on Questions Regarding Fish Passage, Stream
Habitat Improvements and Fish Population Growth

Richard St. Pierre (USFWS) - 07/24/01

1.	Do FMP's take into consideration the impacts of the removal of fish blockages? Is the lack
of habitat a limiting factor to expand current populations of anadromous fish? What are the
limiting factors?

Most dams in the Chesapeake Bay watershed which are being removed or fitted with fishways were
built many decades ago. In most instances anadromous fish populations (e.g., shads and river herring)
are substantially below stock levels recorded in Bay tributaries in the 1960s when these dams were
barriers to migration. Thus, if lack of "suitable" habitat is a limiting factor for population growth, for
the most part those limitations are below dams. Except in a very large scale effort such as that on
the Susquehanna, reopening new (historic) waters to anadromous fish migrations is merely diverting
stock which could otherwise spawn below blockages. Factors which presently limit population
growth in the Chesapeake Bay include those same factors which have upset Bay productivity since
the mid-1970s, including excessive nutrients and siltation, toxic substances, loss of SAV, changes in
availability of preferred foods, etc., coupled with possible overfishing at sea and alteration in oceanic
current and temperature regimes in the NW Atlantic which affect migrations.

2.	What effect does or would dam removal have on stock sizes? Has the "build it and they will
come" philosophy been validated for fish passage? How do these issues relate to establishing
population targets for tributaries for specific species of fish?

Removing dams and providing properly designed and maintained fish passage does result in
immediate use by some anadromous and most resident fishes. Degree of utilization relates more to
having target fish in the vicinity rather than their particular urge to extend their spawning range into
new waters. Some anadromous fishes in the vicinity of fishways may not use the passage due to
improper attraction velocities, turbulence, debris and other physical factors. Effect on stock size,
except in a large scale restoration effort such as that on the Susquehanna, was answered in #1 above.
Population targets could be set for specific tributaries based on available new habitats - but realizing
those gains could take decades.

3.	Do we know what the benefits/impacts have been of removing fish blockages? What is the
fate of those fish and offspring that make it above dams? Can they successfully come back
downstream? Have we taken all the necessary steps to increase the likelihood of survival of
fish coming back down?

Many of the benefits of dam removal or fish passage are esthetic and unquantifiable. Things such as
re-creating a free-flowing stream and/or providing a new fish viewing opportunity have intrinsic value
to the environmentally conscious public. Extension of anadromous fish populations into new waters
may also have real economic benefits in terms of new angling opportunities, and ultimately overall
enhancement to spawning stock size which may lead to reopening of commercial fisheries.
In almost every case involving non-hydro projects, adult and juvenile anadromous fish can move
freely downstream past blockages using surface spills. At large and small hydroelectric dams, the fate
of downstream migrants depends on frequency of spilling, head difference, river flow characteristics,
turbine size, operating schedule (peaking vs. run-of-river) and design (number of blades and blade

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spacing, runner speed). A small hydro project may be much more lethal than a large one. Measured
downstream survival of juvenile shad at Susquehanna River dams, with operational adjustments, is
estimated at 90-98%. Spent adult shad were passed through turbines at Safe Harbor with about 85%
survival. Unless spillbays are properly designed (e.g., proper ogee curve with an adequate plunge
pool), spilling may be more lethal than turbine passage at high dams. Downstream passage of target
species and life stages must be evaluated independently at each project.

4.	Are we pursuing other habitat improvements above new fishways and dam removals? Has
a habitat assessment been conducted in all of these areas? Is stocking being advocated to help
restore stocks more quickly?

Except in the instance of a few dam removals (PA) where we have willing NGO partners (e.g. local
watershed associations), very few instances of widespread upstream habitat improvement efforts can
be documented. River herring habitat assessments have been completed for most tributaries to the
Rappahannock River (VCU study sponsored by EPA) and for several lower Susquehanna River
tributaries (PSU study sponsored by EPA). USGS-Wellsboro is currently investigating pre- and post-
dam removal assessments in several Susquehanna River tributaries (chemical, physical and biological)
in the hopes of developing working models for other streams of similar character. A substantial
Growing Greener initiative is underway in Conodoguinet Creek near the Good Hope dam
(Conodoguinet Creek, Cumberland County, PA) which is scheduled for removal this fall.

Stocking of shad larvae appears to be very effective in bringing fish back to target streams. This has
been used in recent years in the Susquehanna (including several tributaries), the Choptank, Nanticoke,
Patapsco, Patuxent, Potomac, Pamunkey, Mattaponi, and James rivers. As many as 35 million
American shad and 20 million hickory shad larvae and fingerlings have been produced, marked and
stocked each year in Bay waters by PA, MD, VA, USFWS, and tribal entities on the York system.
Stocking of pre-spawned adult shad in the Susquehanna (up to 50,000 per year) resulted in substantial
natural reproduction in the mid-1990s. Stocking of adult river herring in the Susquehanna and its
tributaries above dams and in the James River above Richmond, has shown few positive results to
date. Shad stocking is limited by availability of eggs and it is unlikely that production numbers can
be expanded using current sources and techniques. Stocking of millions of larval river herring could
be a useful tool to supplement stocks destined to pass dams, but techniques and funding for such
activity are not yet readily available.

5.	How do we determine the value of existing and potential habitat for anadromous fish and
how is that information used to select restoration sites? Should we continue to open more
miles or should we maintain, monitor and enhance existing projects? What is the next step?

Studies conducted by VCU (Rappahannock) and PSU (lower Susquehanna), and the ongoing work
by USGS-Wellsboro provide some guidance as to what constitutes high priority versus low priority
restoration sites. Similar work in needed in other Virginia and Maryland tributaries. Tools include
use of existing habitat suitability curves, instream measurements and characterization, fish and food
collections, comparison of known valuable habitats with those under study, experimental stocking
of herring with appropriate monitoring for reproduction and survival, etc.

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Most large stream segments in the Chesapeake Bay watershed will be reopened to anadromous fishes
by 2003. Dam removals (e.g., PA) are relatively inexpensive at an average cost of about $40K, but
fish passage construction, even at relatively low dams, can be very expensive ($100-$250K) and the
amount of quality habitats reopened is not expected to be great. CB2000 requires that the Fish
Passage taskgroup develop new dam removal and fish passage targets by 2002 and the taskgroup will
address this issue at their next meeting. However, it is obvious that EPA funding for fish passage,
coordination and monitoring is decreasing and future accomplishments will be commensurate with
available funds. We may get more "bang for the buck" by using federal FP funding on more or better
monitoring of fish passage utilization and reproduction above dams - which ultimately could be
related to population growth and measures to reach tributary-specific population targets.

Considerable monitoring of anadromous fish presently occurs at select fishways and in open waters
of the Bay and major tributaries. Numerous agencies, gears and locations are involved and some of
these data bases are 25 (Susquehanna) to 50 years old (upper Bay, Potomac). Attached is a draft
outline of most current Alosa monitoring activities and data sources in the Bay. Members of the FP
taskgroup will assemble details of these actions including specific locations, gears, duration, etc.

6.	Is there a relationship between setting aquatic health guidelines and fish passage projects
and tributary specific population targets?

Most elements of this question were already discussed above. The simple answer is - Yes, there is
a relationship among these three activities. With diminished funding future fish passage projects
should target only healthy habitats, and successful recolonization of these habitats (as measured by
intensive monitoring) will be expected to aid in achieving tributary population targets.

7.	What is the relationship between stream restoration goals and fish passage goals.

Fish passage - and especially dam removals - allow anadromous fish to extend their spawning range
into waters previously unavailable to them. Successful utilization of these waters depends on having
(1) effective passages which requiring monitoring, and (2) high quality habitat. Future fish passage
goals must be much more than just accumulating miles. Serious linkage between identifying highest
quality habitats and use of best passage techniques is required. Resident fishes also benefit from
passage/removals by allowing free instream movements and reconnection of isolated subpopulations.
Some of these species (e.g., walleye, smallmouth bass, suckers, carp, gizzard shad, etc.) will make
extensive journeys if provided that opportunity.

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