2007 Status Review of Atlantic sturgeon - National Marine Fisheries ...

The following sections review the impact of dams, dredging, and water quality on Atlantic
sturgeon and their habitat generally. River specific information is presented, as available and
applicable, following the more general discussion.
3.1.1. Dams and Tidal Turbines
Dams for hydropower generation and flood control can have profound effects on anadromous
species by impeding access to spawning and foraging habitat, modifying free-flowing rivers to
reservoirs, physically damaging fish on up- and down-stream migrations, and altering
downstream flows and water temperatures. Patrick (unpublished data-a) estimated that
nationwide, over 50,000 miles of river/lake habitat were blocked by terminal dams (those lowest
in the watershed), which includes the area between the terminal dam and the next upstream
impediment, along the Atlantic, Pacific, and Gulf coasts. Similarly, about 62% of historical
habitat once available to American shad is now impeded by dams (W. Patrick, NMFS,
unpublished data-b). A nonrandom subsample (largest impediments) of these terminal dams
indicated that the majority (65%) do not offer fish passage (Patrick unpublished data). Atlantic
sturgeon do not regularly use fish passage devices; only four Atlantic sturgeon have been
documented to have passed via a fish lift, as these passage facilities are not designed to
accommodate adult-sized sturgeon. Three of the Atlantic sturgeon were found in Lake Molutrie,
SC that evidently passed the St. Stephens fish lift. The only other observed Atlantic sturgeon
using a fish passage device was recently observed in September of 2006 using the Holyoke Dam
fish lift, which is located on the Connecticut River, Massachusetts. However, shortnose sturgeon
have been observed frequently (4.7 sturgeon per year between 1975 and 2002) to have passed the
Holyoke Dam via its fish lift (Kynard 1996, Gephard and McMeney 2004).
Physical damage and mortality can also occur from anadromous fish migrating through the
turbines of traditional hydropower dams on their downstream migration. Though Atlantic
sturgeon have not been observed to use fish passage devices, tidal power plants are a potential
threat to Atlantic sturgeon migrating up- and down-stream (Dadswell and Rulifson 1994,
Dadswell 2006). Tidal power plants use marine turbines, similar to windmill technology, to
generate power using the force of both incoming and out-going tides. These marine turbines can
strike migrating fish such as adult Atlantic sturgeon, thus causing physical damage or mortality;
injuries or mortality can also occur via shear, pressure flux, and cavitation effects on fish during
turbine passage (reviewed in Dadswell and Rulifson 1984). Currently, there are two tidal power
projects in operation along the range of Atlantic sturgeon, with many more projects being
proposed. The Annapolis River tidal power plant (Nova Scotia), built in 1982, was constructed
as a demonstration site for marine STRAFLO turbines and consisted of a rock-filled dam
housing the turbine and sluice gates (M. Dadswell, Arcadia University, Pers. Comm. 2006). The
negative impacts of the Annapolis tidal turbine on Atlantic sturgeon (150 – 200 cm TL) appear to
be great, as the probability of lethal strike from the turbine ranges between 40 –80% (M.
Dadswell, Arcadia University, Pers. Comm. 2006) and at least three severed, gravid females
have been observed below the power plant (Dadswell and Rulifson 1994) (Figure 21). Within
the United States, one marine turbine project has been proposed on the East River, New York
(Angelo 2005, CBS News 2006). Beginning in November of 2006, an 18-month pilot project
using two slow speed tidal turbines were placed in the East River to determine their impacts on
marine life. Following the 18-month project four more tidal turbines are to be installed to further
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