was in flood, 8.1 m and 5.5 m deep, respectively,
where eggs were collected. Temperature at both lo-
cations was 18.3° C. Additional eggs were collected
during late March and April 1994 at river km 201 to
221 when water temperatures ranged from 18.8 to
20.1°C.
Studies are underway to genetically characterize
the Gulf sturgeon. Results to date show definitive
inter-regional differentiation of mtDNA genotypes
indicating that fish from rivers in the eastern, cen-
tral and western Gulf are genetically distinct (Isaac
Wirgin personal communication). Further, it is sug-
gested that the homing fidelity of Gulf sturgeon
may be quite high and that mtDNA differentiation
among fish from geographically proximal rivers
may be possible.Reasons for declineExploitationEarly utilization of Atlantic sturgeon can be traced
to 2190 B.C. in New England (Ritchie 1969), how-
ever, major fisheries for Atlantic sturgeon began
during the last quarter of the 19th century. Thesesturgeon moved into coastal rivers to spawn. Al-
though most historical sturgeon landings data are
probably inaccurate and do not include fishing ef-
fort, they do reflect major trends in harvest. Some
Atlantic sturgeon landings may have included the
smaller (maximum size 1.4 m TL) shortnose stur-
geon,A.brevirostrumup until 1973 when this spe-
cies was listed as endangered. However, most land-
ings are probably based on the much larger Atlantic
sturgeon.U.S.landings, recorded initially in 1880 by
theUSFish Commission, peaked about 1890 when
approximately 3350 mt were landed (Figure I). Be-
cause the fish were so vigorously pursued. all major
fisheries collapsed within about 10 years with land-
ings in 1901 less than 10% (295 mt) of the former
peak. Today, fisheries are still depressed and more
closely regulated. During 1990–1992, mean total
U.S. landings were 82.4 mt or 2% of that reported in
1890.
The major U.S. historical fisheries for the Atlan-Figure1.Reported landings of Atlantic and Gulf sturgeon. Data
lor Canada prior to 1940 show only landings from the Saint John
River. New Brunswick (a. M. Dadswell personal communica-
tion); after 1940. the figure shows combined landings for the
Saint John and St. Lamrence (Quebec) rivers (a + b, G. Trencia
based on NMFS data and may include shortnose sturgeon prior
to 1972. Gulf of Mexico landings arc based on J. M. Barkuloo^10.
personal communication). U.S.-Atlantic Coast landings are
fisheries focused on the spring migrations when the
during summer and fall when they are in coastal riv-
ers. High water termperature was suggested as the
main cause of feeding inactivity in the Suwannee
River (Mason & Clugston 1993). Although this riv-
er remained cooler than near-shore Gulf of Mexico
waters during summer, river temperatures were still
believed to exceed optimum temperature for feed-
ing and growth. Foster (1993), located juvenile and
adult Gulf sturgeon in 29°Cwater in the Suwannee
River using radio transmitters.
Gulf sturgeon spawn inthe upper reaches of the
Suwannee River (Clugston et al. 1995). The small-
est sturgeon (76 g and 85 g) ever reported from this
river were captured at river km 215 and 237 during
the winter of 1991. Verification of spawning in this
area was accomplished with the collection of stur-
geon eggs on artificial substrates near river km 215
in April 1993 (Marchant & Shutters 1996). The river