some areas, a small fall spawning migration consist- spring and also a substantial portion of the fish har-
ing of ripe Atlantic sturgeon adults has also been vested in the autumn fishery. In addition, it is be-
reported (Smith et al. 1984). Although actual lieved that the Hudson River provides a substantial
spawning locations are not well known they are be- number of the juveniles that aggregate in the Dela-
lieved to include flowing water over hard substrates ware Bay. In 1990, studies suggested that there may
(rocks, rubble, shale, and sand). be genetic structuring among Atlantic sturgeon in
Information on the early life history for both sub- various Atlantic coast drainages (Bowen & Avise
species is scarce and based primarily on culture 1990). This hypothesis was supported when Atlan-
studies. For Atlantic sturgeon, the highly adhesive tic sturgeon from the Saint Lawrence and Saint
eggs require incubation times of 94 h (20°C) to John rivers, Canada, the Hudson River, and rivers
about 140 h (18° C) (Smith et al. 1980). The yolksac is in Georgia were identified as genetically distinct
absorbed in about 10 days, and the small fish begin a populations (Waldman et al. 1996a, b).
demersal existence. Hatching time for artificially Much information exists on the biology of Gulf
reared Gulf sturgeon eggs ranges from 54 h at 22.7– sturgeon in the Apalachicola and Suwannee rivers
23.3°C to 85 hat 18.4°C (Parauka et al. 1991). Little of Florida (Huff (1975, footnote 7), Wooley & Cra-
is known of the behavior and habitat requirements teau 1985, Odenkirk 1989, Foster 1993, Mason &
of these small fish and it is assumed that they slowly Clugston 1993, Clugston et al. 1995). Gulf sturgeon
move downriver from the spawning sites. Once At- usually begin to migrate into coastal rivers from the
lantic sturgeon subadults attain a size of≥ 30 cm, Gulf of Mexico during mid to late February as the
they are regularly captured in tidally influenced rivers warm to 16–19° C. Migration continues
lower river and estuarine areas (Dovel & Berggren through May and peaks during late March or early
1983, Lazzari et al. 1986, Collins et al. 1996). Some April in the Suwannee River, when the river tem-
movement of juveniles between river systems oc- perature reaches about 20° C (Foster 1993, Clugston
curs (Dovel & Berggren 1983). Most juvenile Atlan- et al. 1995). Fish of all sizes (1.0–75.0 kg) move up-
tic sturgeon remain in slightly brackish water near river and settle in various reaches of the river from
the river mouth/estuarine zone for a number of river km 24 to km 215. Downstream movement usu-
months or years (Kieffer & Kynard 1993) and then ally begins in mid-November as the water cools to
move into coastal and continental shelf waters 20° C. All sturgeon in the Suwannee River, except
where they grow and mature. young of the year, return to the Gulf of Mexico by
Information on the characteristics of Atlantic early December. Small sturgeon (0.2–2.5 kg) re-
sturgeon populations is being developed. Based on main in and near the river mouth during winter and
tagging studies, Atlantic sturgeon are known to un- spring. Larger fish move to unidentified areas in the
dertake extensive coastal migrations (Holland & Gulf of Mexico.
Yelverton^8 , Murawski & Pacheco^1 , Hoff^2 , Rulifson Gulf sturgeon over one year of age do not eat
& Huish 1982, Smith et al.^6 , Dovel & Berggren during the summer and fall despite an abundant
1983). However, tagging studies provide little infor- supply of benthic organisms in the Suwannee River
mation on the source of recruits to various stocks (Mason & Clugston 1993). In spring, stomachs of
and such information is basic to effective manage- subadults and adults that migrate from the Gulf of
ment. Recently, using mitochondrial DNA analysis, Mexico into the Suwannee River and small stur-
Waldman et al. (1996a) found that the Hudson Riv- geon that remain near the river mouth are full of
er contributes most of the Atlantic sturgeon cap- benthic invertebrates. Based on capture, mark and
tured in the New Jersey intercept fishery in the recapture studies, juvenile and adult Gulf sturgeon
decrease in weight during the summer while in
freshwater (Wooley & Crateau 1985, Clugston et al.
1995). Net growth of Gulf sturgeon results from a
Series of weight gains while they are in the Gulf of
Mexico during winter and spring, and weight losses
(^8) Holland, B. F., Jr. & G. E Yelverton. 1973. Distribution and bi-
ological studies of anadromous fishes offshore North Carolina.
N.C. Dep. Nat. Econ. Res. Spec. Sci. Rep. 24. Morehead City. 132
pp.