EPA's Vessel General Permit and Small Vessel General

Keswick dams). Other threats include potentially lethal temperature limits, harvest, entrainment
by water projects and toxins and invasive species (Adams et al. 2007, Erickson and Webb 2007,
Lackey 2009). Since this species is composed of a single spawning population within the
Sacramento River, stochastic variation in environmental conditions and significant fluctuations
in demographic rates increases the risk of extinction for this species.
Studies from other sturgeon species indicate that sturgeon readily bioaccumulate contaminants.
White sturgeon from the Kootenai River have been found to contain aluminum, arsenic,
cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium, zinc,
DDE, DDT, PCBs and other organochlorines (Kruse and Scarnecchia 2001). Mercury has also
been identified from white sturgeon of the lower Columbia River (Webb et al. 2006). Numerous
organochlorines, including DDT, DDD, DDE, chlordane and dieldrin have also been identified in
these fish (Foster et al. 2001). Observed concentrations are likely sufficient to influence
reproductive physiology.
Shortnose Sturgeon
Shortnose sturgeon occur along the Atlantic Coast of North America, from the St. John River in
Canada, south to the St. Johns River in Florida. NMFS’ recovery plan (1998b) recognized 19
wild populations based on their strong fidelity to their natal streams and several captive
populations (from a Savannah River broodstock) that are maintained for educational and research
purposes (NMFS 1998b).
Shortnose sturgeon are generally anadromous, but may migrate between fresh and salt water for
reasons other than spawning. They can also maintain freshwater resident populations. In general,
shortnose sturgeon are benthic fish that occupy the deep channel sections of large rivers or
estuarine waters of their natal rivers and will migrate considerable distances. Dadswell (1979 in
Dadswell et al. 1984)(1979 in Dadswell et al. 1984)(1979 in Dadswell et al. 1984) (1984a)
observed shortnose sturgeon traveling up 160 km between tagging and recapture in the St. John
estuary and it is not uncommon for adults to migrate 200 km or more to reach spawning areas
(Kynard 1997). After spawning in the spring, adults tend to migrate rapidly downstream to
feeding areas in the estuary or to tidally influenced fresh water (see Dadswell et al. 1984a).
Young-of-the year shortnose sturgeon move downstream after hatching, remaining in fresh water
for about 1 year (Kynard 1997). Initially, young shortnose sturgeon will reside short distances
from spawning areas and as they grow will tend to move further downstream (see Dadswell et al.
1984a). By age 3 or older juvenile sturgeon will spend a large portion of their year at the salt-
and fresh water interface of coastal rivers (NMFS 1998c).
Habitat use in fresh water during summer and winter months overlaps between adult and age-1
shortnose sturgeon (O'Herron II et al. 1993, Kynard et al. 2000, Moser et al. 2000c). Kynard et
al., (2000) found that both age classes preferred deep-water curves with sand and cobble to
higher velocity runs, particularly during winter months and shifted to channel habitat as water
temperatures rose in summer months. In the Connecticut River and the Merrimack, Kynard et al.,
(2000) found shortnose generally used water about 3 meters deep, ranging from less than a meter
to about 15 meters deep.
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