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Sturgeon fossil records date back more than 150 million years, making them among the oldest vertebrates. There are 26 species of sturgeon, with eight being found in North America. Two species of sturgeon are native to the Chesapeake Bay, the shortnose and Atlantic sturgeon.
Historically, Atlantic sturgeon were of significant commercial importance on the East Coast being harvested primarily for their highly prized roe or caviar. In the late 1880's harvest peaked at about 7 million pounds, of which approximately 10% was harvested from the Chesapeake Bay. Commercial catch declined rapidly after the turn of the century, primarily due to overfishing, with annual harvests from 1905 to the 1990's amounting to less than 5% of the record catch. Populations were unable to rebound despite reduced fishing pressure because of a loss of spawning grounds and reduced water quality.
A moratorium on all US commercial harvest was established for Atlantic sturgeon in 1997. Currently, the population of Atlantic sturgeon in the Chesapeake Bay appears to be extremely low with no young of year fish being caught during surveys between 1950 and 2003. However, in the Spring of 2004, young of year sturgeon were observed in the James River providing an indication that though rare and given the right environmental conditions, spawning ang hatching is possible. The unique life fishery of sturgeon, requiring 10-15 years to reach sexual maturity and only spawning every 2-3 years, contributed to its population decline and presenting challenges to its recovery.
As a key initial step in developing an Atlantic sturgeon restoration program, Maryland Department of Natural Resources Fisheries Service and its partners, GenOn at the Chalk Point Power Plant, Delaware Department of Natural Resources and Environmental Control, U.S. Fish and Wildlife Service, and UMCES Finfish Aquaculture Program at Horn Point Laboratory are in the process of establishing the necessary broodstock population as recommended by the Atlantic States Marine Fisheries Commission (ASMFC, 1996).
Among the ASMFC sturgeon restoration protocols are recommendations to ensure maximum genetic diversity and include a minimum broodfish population of 100 animals of six year classes and preferably utilizing animals from the same or adjacent river system. Currently over 200 Atlantic sturgeon of 1992 or younger year class are being maintained by the partners, but all of this stock is from the Hudson River and the sex and maturity of these fish are unknown.
To establish the desired broodstock population in Maryland several objectives mush be achieved, including, 1) identifying the genetic diversity of existing stock through genetic profiling of all animals, and 2) conducting studies to identify methods to train wild fish collected from the Bay to consume commercial feed.
Feed training of wild-caught Atlantic sturgeon
Captured wild fish do not readily train onto commercial diets (and in some cases, natural food) often resulting in excessive weight loss, reduction in fish condition factor and mortality. Preliminary efforts to force feed sturgeon resulted in mixed results, yet some had success force feeding captured Atlantic sturgeon by inserting gelatin encapsulated natural foods into the alimentary tract.
For feeding trials conducted at HPL, sturgeon were captured from the Delaware River and Chesapeake Bay over the Summer of 2003 and 2004. In our study, two methods of feeding are evaluated: passive introduction of natural foods and forced feeding of a natural-food A "slurry" of shrimp, shad roe, squid, and bloodworms. After several weeks, commercially available pellet feed is added to the mixture and ultimately commercial diets.