The Atlantic sturgeon, Acipenser oxyrhynchus,
and the shortnose sturgeon, Acipenser brevirostrum, are demersal,
anadromous species distributed along the Atlantic coast of North
42.1). Both species occcur between Florida and New Brunswick,
but the distribution of the Atlantic sturgeon extends further
north to Labrador. Both species migrate from the marine environment
to freshwater to spawn during late winter-early summer, with these
migrations occurring later in the year at higher latitudes. In
water where the species co-occur, the shortnose sturgeon tends
to begin its migration earlier than the Atlantic sturgeon. Spawning
generally occurs in the lower sections of rivers, below the fall
line. Eggs are deposited on hard surfaces on the bottom where
they adhere for 4 to 6 days until hatching. Juvenile sturgeon
remain in freshwater for their first summer before migrating to
estuaries in winter. Juveniles remain in the freshwater-estuary
system for 3 to 5 years before migrating to the near-shore marine
environment as adults. Migration into the marine environment has
only recently been documented for the shortnose sturgeon.
Tagging studies indicate that Atlantic sturgeon migrate extensively
in the marine environment; fish tagged in the Hudson and Delaware
Rivers have been recaptured as far north as coastal Maine and south
to North Carolina.Sturgeons from southern systems have more restricted
marine migrations, remaining closer to their natal rivers.
Sturgeons are considered to be
among the most primitive bony fishes, with origins dating back 120
million years. Sturgeons are characterized by 5 rows of bony plates
or scutes along the back rather than scales and have prominent barbells
under their snout used as sensory organs. Juveniles and adults of
both species are benthic (or bottom) feeders, consuming a variety
of crustaceans, bivalves, worms, plants and occasionally small fish.
Shortnose are smaller than Atlantic sturgeon and may attain maximum
sizes of approximately 100 cm (40 in.) and 23 kg (50 lbs) whereas
Atlantic sturgeon reach maximum sizes of 430 cm (170 in) and 363
kg (800 lbs). Both species are long lived potentially reaching ages
in excess of 60 years for females and about 30 for males. Maturity
occurs in female shortnose sturgeon between the age of 7 and 15,
with maturity at younger ages at the southern end of the distributional
range. Atlantic sturgeon exhibit a similar latitudinal pattern in
female age at maturity with southern fish maturing between age 7
to 19 compared to sturgeon in the St. Lawrence River, Canada reaching
maturity in 27 to 29 years. Both species are highly fecund, with
total egg production increasing proportional to body size with individual
fish spawning once every 3 to 5 years.
Management of both species is
conducted under the auspices of the Atlantic States Marine Fisheries
Commission (ASMFC). An Interstate Fishery Management Plan (FMP)
was implemented in 1990 which implemented strict state regulations
on sturgeon fisheries. The Plan was amended in 1998 in response
to a marked decline in sturgeon population abundance. Fishing is
now prohibited in all participating states' waters, and a moratorium
has been in effect in the EEZ since 1999 under provisions of the
Atlantic Coastal Fisheries Cooperative Management Act (ACFCMA).
The goal of the FMP is to restore sturgeon spawning biomass to provide
for a sustainable fishery. Management now requires at least 20 protected
year classes of females to be present in any river stock of sturgeon
before considering allowing a fishery on that stock. The FMP also
emphasizes research programs to evaluate stock status of Atlantic
The National Marine Fisheries
Service and U.S. Fish and Wildlife Service received a petition to
list Atlantic sturgeon as endangered, which was reviewed in 1998.
The endangered status was denied but the species remained as a ‘species
of concern’. The status of Atlantic sturgeon is currently
being re-evaluated. During the 20th century, shortnose sturgeon
declined throughout its historic range and in 1967 it was listed
as endangered and has since remained in this status.
Atlantic and shortnose sturgeon
fisheries began with native American Indians prior to the arrival
of European settlers into North America. Colonists records indicate
exports of sturgeons to Europe as early as 1628. A substantial Atlantic
sturgeon fishery existed into the late 1800s, with landings as high
as 3500 mt. However, overfishing, habitat degradation and reduced
demand contributed to population decline so that only incidental
landings occurred during 1900 to 1950. Landings increased during
the 1950s to 1980s, particularly in the Carolinas and ranged between
45 mt and 115 mt per year (Figure 42.2[Fig 42.2
Data]). Increased landings in the early 1990s were due to increased
catches in ocean fisheries off New York and New Jersey (Table
42.1). As part of the FMP implemented by the Atlantic States
Marine Fisheries Commission, a moratorium was established in 1998
which prohibited the harvest of wild Atlantic sturgeon. Shortnose
sturgeon were rarely the target of commercial fisheries and were
taken primarily as incidental bycatch in other fisheries. Possession
of shortnose sturgeon is prohibited due to its endangered species
Vessel Survey Indices
Atlantic sturgeon are taken only
incidentally in the NMFS bottom trawl surveys. No shortnose have
been taken in the survey. The information from these surveys is
therefore inadequate to determine any population trends. State surveys
that capture both juvenile and adult Atlantic sturgeon.are conducted
in rivers, estuaries and coastal waters throughout the range and
are used to determine stock status. In addition, tag release/recovery
programs are underway in the Delaware River and the Chesapeake Bay
and tributaries. Shortnose sturgeon are also sampled by state agencies
between Maine and Florida.
Each river system in which Atlantic and shortnose
sturgeon occur is considered to contain a unique stock despite
the mixing of individuals in coastal waters. A review of Atlantic
sturgeon stock status in 1998 by the National Marine Fisheries
Service and the U.S. Fish and Wildlife Service concluded that
although the abundance of sturgeon had declined significantly,
adequate spawning stock still remained for the persistence of
the population and for juvenile production. Habitat improvements
and fisheries conservation were recommended to improve the likelihood
of full population recovery.
Shortnose sturgeon were listed in 1967 as an
endangered species but in some systems abundance may be increasing
to levels that would allow reconsideration of their endangered
status. The shortnose population in the Saint John River, New
Brunswick Canada is among the largest in North America, and the
Hudson and Delaware Rivers also support significant numbers of
Biological Reference Points
The Atlantic sturgeon recovery plan requires
is that at least 20 protected year classes of female fish must
be present in a river system stock before a fishery can be allowed.
Upon recovery, the target fishing mortality of Atlantic sturgeon
in the Hudson River will be 0.03, the rate that maintains eggs
per recruit (EPR) at 50% of the EPR as F=0.0.
The long term objective of the shortnose sturgeon
recovery plan is to restore populations to levels that will maintain
genetic diversity and avoid extinction. The short term goal is
to rebuild populations throughout the range and remove the species
from the Endangered Species list.
Stock abundance of Atlantic and shortnose
sturgeons steadily declined throughout the 20th century as a result
of overfishing and habitat destruction. Fisheries for Atlantic sturgeon
existed until 1997 when a moratorium was declared from Maine to
Florida. Shortnose sturgeon was declared an endangered in 1967 under
authority of the Endangered Species Act of 1966. Research into the
biology, habitat requirements and stock status of both of sturgeons
continues, with the goal of restoring both species to sustainable
levels of abundance.
ASMFC. 1998. Atlantic sturgeon stock assessment:
peer review report. March, 1998. Washington, D. C.
ASMFC. 1990. Fishery Management Plan for Atlantic Sturgeon. Fisheries
Management Report 17. Washington, D.C.
Dadswell, M.J., B.D. Taubert, T.S. Squiers. D. Marchette, and J.
Buckley. 1984. Synopsis of biological data on shortnose sturgeon,
Acipenser brevirostrum LeSueur 1818. NOAA Tech. Rep. NMFS-14,
FAO Fisheries synopsis No. 140, 45 p.
Gilbert, C.R. 1989. Species profiles: life histories and environmental
requirements of coastal fishes and invertebrates (Mid-Atlantic Bight)
Atlantic and shortnose sturgeons. U.S. Fish. Wildl. Serv., Biol.
Rept. 82(11.122); U.S. Army Corps of Engineers TR EL-82-4.
NMFS. 1998. Final Recovery Plan for the shortnose sturgeon Acipenser
brevirostrum; Prepared by the Shortnose Sturgeon Recovery Team.
December 1998. Washington, D.C.