Atlantic Sturgeon (acipenser oxyrinchus)
Life as a Sturgeon
The Atlantic sturgeon is an anadromous fish, meaning it
spends most of its life in brackish or salt water and migrates into freshwater
to spawn. They may live to 60 years of age. Atlantic sturgeon mature very
slowly. Sexually mature males are at least 11 to 12 years old and weigh
up to 100 pounds, while mature females are 18 to 20 years old and weigh
more than 100 pounds.
Males migrate into freshwater during March and April,
one month before females. They do not school together but meander singly.
Females begin spawning as soon as they reach spawning grounds. Females
lay 1 million to 2-1/2 million eggs in flowing water up to 60 feet deep.
Both males and females may remain in the river until late fall before
migrating back to the Atlantic. After hatching, the young tend to remain
in their natal areas up to five years before beginning their journey to
the ocean. Immature Atlantic sturgeon may also wander in and out of the
Atlantic coastline.
Sturgeon use their snouts and barbels to root around in
bottom sediments, vacuuming up organisms with their soft mouths. Their
diet consists of worms, snails, shellfish, crustaceans, and small fish,
as well as large amounts of mud and debris.
Other than sharks and people, sturgeon have few predators.Currently,
there is no legal fishery for Atlantic sturgeon along the Atlantic coast.
However many Atlantic sturgeon are still taken as incidental by catch
in other fisheries.Though these fish cannot be kept, many do not always
survive after release.Biological characteristics of the Atlantic sturgeon,
such as slow growth, advanced age at maturity, and long periods between
spawning, make it particularly vulnerable to human-induced impacts and
changes to its habitat.
Cause For Concern
Harvesting Atlantic sturgeon was an important industry
from colonial times to the turn of the century. During the 17th century,
sturgeon meat, eggs and oil were exported to Europe. The most valuable
part of the fish was its eggs, or roe. Prepared as caviar, this delicacy
was in high demand in Europe. The delicate meat, comparable to pork or
swordfish, was smoked and eaten. Even sturgeon air bladders were valuable.
They were used to make isinglass (a clear gelatin), jellies, clarifying
agents for beverages, plasters, waterproofing agents, adhesives and lubricants.
By 1850 sturgeon meat and roe became popular in this country as well.
By the late 1800s, landings as high as 7 million pounds were reported
for all the states, collectively.
Traditionally, Atlantic sturgeon fishermen worked the
Hudson River in New York, the Susquehanna River in Pennsylvania, the Delaware
River in Delaware, the Potomac and St. MaryÕs rivers in Maryland, and
the York and James rivers in Virginia. They used large drifting gill nets,
some 1,500 feet long and 21 feet deep with a mesh of 13 inches.
By the 1920s, the average annual harvest was reduced by more than 90
percent with total landings reported at only 22,000 pounds. In the Chesapeake
Bay, sturgeon catch peaked in 1890s at a record level of more than 700,000
pounds. More recently in the Chesapeake Bay, sturgeon were being caught
at levels probably less than 2,200 pounds.
Then in June 1998, the Atlantic Marine Fisheries Commission closed the
entire coast to Atlantic sturgeon fishing for the next four decdes. Stock
assessments indicated that only remnant populations of Atlantic sturgeon
remain along much of the East Coast.
Restoring Atlantic Sturgeon
Restoration of Atlantic sturgeon is under way. Because so little is known
about the migration patterns of Atlantic sturgeon, the U.S. Fish and Wildlife
Service, in partnerships with several states, has initiated a program
to tag wild sturgeon along the Atlantic Coast and the Gulf of Mexico.
People who catch a tagged fish, report tag numbers to the U.S. Fish and
Wildlife Service. In this way, individuals help provide information to
biologists who are tracking distribution, mortality, age, growth and coastal
migration patterns of the fish.
Other restoration efforts include producing hatchery-reared fish, for
further study and for release into the wild. In 1996, three thousand hatchery-raised
Atlantic sturgeon were released into the Nanticoke River.
The Future of the Fish
It will take more than a moratorium to bring Atlantic sturgeon back to
the Chesapeake Bay. Habitat quality is crucial to the survival of the
species. For instance, increased development and deforestation has reduced
the amount of forest litter (decaying organic matter found on the forest
floor) entering streams and rivers. Forest litter is necessary for egg
attachment and survival.
Water quality is also critical to the survival of adults and juveniles.
Excessive amounts of nutrients in waterways can create sudden blooms of
phytoplankton. After the phytoplankton die, decomposition uses up large
amounts of oxygen. This can lead to dangerously low dissolved oxygen levels
along the bottom where eggs and larvae grow and sturgeon feed.
Like all anadromous fish, Atlantic sturgeon must have access to their
spawning grounds. By removing blockages or altering the design of dams
to accommodate fish passage, sturgeon can reach the upstream areas critical
to their reproduction.
With citizens working in cooperation with local, state and federal agencies
to lower fishing mortality, reduce pollution, provide fish passage and
possibly enhance stock through hatchery production, the Atlantic sturgeon
may once again become a vital and familiar part of the Chesapeake Bay
heritage.
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