51813_Sturgeon biodioversity an.PDF

with landings substantially reduced from those re-
ported before the turn of the century (Figure 1).
From about 1951–1982, U.S. landings generally ex-
ceeded those reported from Canada. However,
there has been a consistent trend of increased catch-
es from Canada with 1990–1992 landings (mean 130
mt) near peak levels.
There are two major Canadian fisheries: one cen-
tered in the St. Lawrence River between St. Joa-
chim and Cacouna, Quebec (Guy Trencia personal
communication); and, another in the Saint John
River, New Brunswick (Michael Dadswell personal
communication). Both are directed fisheries. The
increase in Canadian landings during the past 12
years is primarily from the St. Lawrence River fish-
ery, which supports about 35 fishermen. Fish taken
from the St. Lawrence River are rarely mature. In
recent years, only 1–2 fisherman fish for, Atlantic
sturgeon in the Saint John River fishery with annual
landings on the order of 5–10 mt.
The Gulf sturgeon fishery also experienced a ma-
jor decline since about the turn of the century (Fig-
ure 1) based on commercial landing statistics com-
piled by Barkuloo^10. Directed fisheries occurred
only along the Florida (FL) and Alabama (AL)
coasts. There are periods of increased harvest but,
as with the Atlantic sturgeon, no effort information
is available to calculate catch per unit effort.
Over-harvesting is believed to be the single major
cause of the precipitous declines in abundance of
Atlantic sturgeon (Ryder 1890, Vladykov & Gree-
ley 1963, Hoff^2 , Taub^5 ). Vulnerability to overfishing
is clear as mature fish were relatively easily cap-
tured during spring spawning migrations and juve-
niles were harvested from estuarine nursery hab-
itats.

such dams include those at the head of the Andros-

coggin River (1807) and Kennebec River (1837) in

Maine, the dam at Lawrence (1847) on the Merri-

mack River in New Hampshire, and the Enfield

Rapids Dam on the Connecticut River (Hoover^11 ,

Galligan 1960, Murawski & Pacheco^1 ). In South

Carolina, Atlantic sturgeon have been excluded

from historic spawning sites since about 1870 when

mill dams and water supply dams were constructed

on the Peedee, Wateree, Congaree and Savannah

rivers (Leland 1968). Similarly, dams have limited

Gulf sturgeon access to migration routes and histor-

ic spawning areas throughout the Gulf of Mexico

(Murawski & Pacheco^1 , Wooley & Crateau 1985,

USFWS & Gulf States Marine Fisheries Commis-

sion^12 ). A dam constructed in 1962 across North Bay

of the St. Andrew Bay system in FL prevents pas-

sage of all anadromous species as does the Ross

Barnett dam on the Pearl River. The Jim Woodruff

Lock and Dam constructed in 1957 on the Apalach-

icola River also appears to provide complete re-

striction as no tagged sturgeon have been taken up-

river of this structure and no evidence exists which

indicates that the Gulf sturgeon can pass through

the lock system (USFWS & Gulf States Marine

Fisheries Commission^12 ).

Pollution and industrialization

Much of the Atlantic sturgeon’s historic riverine

habitat has been degraded by water pollution and

extensive dredging (Taub^5 ). Along the middle At-

lantic coast and the Gulf of Mexico, water degrada-

tion from industrial and domestic discharges im-

pacted spawning and nursery habitats (Hoover^11 ,

Galligan 1960, Leland 1968, Murawski & Pacheco^1 ,

Barkuloo^10 ). The 1970 National Estuary Study in-

dicated that dredging and filling activities were par-

ticularly destructive to fish habitat and reported

that 73% of the U.S. estuaries have been moderate-

Damming of spawning rivers

Construction of dams in some northeastern and

southeastern rivers excluded Atlantic sturgeon

from historical spawning sites. In the northeast, 11

Hoover, E. E. 1938. Biological survey of the Merrimack wa-

tershed. Fish Game Comm., Concord. 238 pp.

(^12) U.S. Fish and Wildlife Service & Gulf States Marine Fisheries
Commission. Gulf Sturgeon Recovery/Management Plan. At-
lanta, Georgia. 170 pp.
(^10) Barkuloo, J. M. 1988. Report on the conservation status of the
Gulf of Mexico sturgeon, Acipenser oxyrhynchus desotoi. U.S.
Fish and Wildlife Service, Panama City. 33 pp.