Sturgeon Restoration


Atlantic sturgeon are a long-lived, estuarine dependent, anadromous fish. Atlantic sturgeon were an important species targeted by early settlers in the Chesapeake Bay (Hildebrand and Schroeder 1928). Landings were reported to be 300,000-400,000 kg (136,000-181,000 lbs.) annually in the 1890's. High exploitation rates, degraded water quality, and the building of stream blockages reduced the population. By 1928, Atlantic sturgeon were rarely caught north of the Potomac River (Merritt 1992). Maryland closed the fishery for sturgeon in 1996. There have been no young of year Atlantic sturgeon caught in Maryland's juvenile finfish survey for the past 45 years (Speir and O'Connell 1996). As recently as two decades ago, Atlantic sturgeon were encountered so infrequently that they were considered to be biologically extirpated, or below minimum viable population size in the Chesapeake Bay (Secor et al. 1997). In recent years, a Chesapeake Bay spawning population was documented in Virginia's James River. Atlantic sturgeon observations are now routinely documented throughout the Chesapeake Bay, although many of these fish are migratory juveniles that originate from other river systems and forage throughout the mid-Atlantic. In April 2012, Atlantic sturgeon were designated as "endangered" by the National Marine Fisheries Service (NMFS) under the federal Endangered Species Act (ESA). NMFS assessment found that Atlantic sturgeon are in danger of extinction within a specific geographic range. NMFS determined that there are five Distinct Population Segments (DPS) of Atlantic sturgeon in U.S. waters: 1) Gulf of Maine (threatened), 2) New York Bight (endangered), 3) Chesapeake Bay (endangered), 4) Carolina (endangered) and 5) South Atlantic (endangered). Since the Chesapeake Bay DPS is now listed as a federally endangered species, catch or possession is strictly prohibited.

Maryland Department of Natural Resources Fisheries Service (DNR) Hatcheries Division, in partnership with the University of Maryland and the U.S. Fish & Wildlife Service (USFWS) conducted an experimental release of Atlantic sturgeon in 1996. Approximately 3,000 hatchery-produced juveniles were released into the Nanticoke River, a Chesapeake Bay tributary on Maryland's Eastern Shore. A subsequent reward program recorded 462 first-time captures of these fish (14% recapture rate) between release and 2001. Multiple recaptures were frequent, indicating excellent survival after capture in commercial fishing gears. During this time, 555 wild sturgeon were also captured in the Chesapeake Bay. These fish were primarily of immature, sub-adult migratory size (16-95"in length). No wild, young of year or adult sturgeon were reported. Since a limited release of hatchery fish produced such a large number of hatchery recaptures and no wild young of year or adults were encountered, it appears unlikely that any natural reproduction occurred in Maryland during the reward program timeframe.

The experimental release indicated the potential to restore Atlantic sturgeon in Maryland through a hatchery-based stocking program. DNR began a cooperative partnership with the University of Maryland, NRG Energy, and USFWS to support Atlantic sturgeon restoration in Maryland. Each partner contributes unique resources to the project.

DNR has been rearing a captive population of sturgeon since 1996. NRG Energy cultures the captive stock at their Chalk Point Aquaculture Facility in Aquasco, MD. Our long-term goal is to develop these fish into reproductively mature brood stock that can be used to produce larval and juvenile sturgeon for conservation efforts. Currently we have approximately 100 sturgeon in the captive population. The largest fish are beginning to reach sexual maturity. The Atlantic States Marine Fisheries Commission (ASMFC) Breeding and Stocking Protocol (ASMFC SR #22) contains guidelines for jurisdictions attempting restoration. These protocols recommend spawning strategies, including identification of genetically appropriate brood stock origin, minimum brood stock population size, and genetic diversity of the captive population. These guidelines will increase the chance for successful reintroduction efforts.

DNR collected wild juvenile Atlantic sturgeon caught in the Chesapeake Bay and its tributaries through the Maryland Sturgeon Reward Program. Fish that were appropriate for inclusion into the captive brood population were transported to the University of Maryland's Aquaculture and Restoration Ecology Laboratory (AREL) in Cambridge, MD. At AREL, captive brood fish were trained to consume prepared commercial diets in the hatchery. The Maryland Sturgeon Reward Program ceased operations in March 2012 due to the federal ESA listing, which prohibits sturgeon capture and transport by commercial fishermen.

NRG Energy and DNR developed another cooperative project at NRG Energy's Potomac River Generating Station. A pilot trial for Atlantic sturgeon culture began in the summer of 2006. Positive results from the pilot effort led to an expanded culture trial in 2007. As part of the renewed partnership in 2008, NRG Energy provided funding for five years to support Atlantic sturgeon restoration activities. The Potomac River Generating Station sturgeon culture facility produced larval and juvenile sturgeon. The primary goal was to investigate streamside culture for imprinting purposes. Atlantic sturgeon are believed to imprint to their natal rivers, allowing them to return to spawn upon maturity. It is critical that any fish stocked as larvae or juveniles will imprint to the target tributary, so that they may successfully return to spawn. The facility also served as an education and outreach resource for sturgeon conservation specifically, and Chesapeake Bay ecology in general. In 2012, NRG Energy closed the Potomac River Generating Station and the sturgeon were transferred to DNR's Manning Hatchery in Brandywine, MD. This valuable cooperative project enabled restoration biologists to develop tools and techniques that are critically important to successful hatchery-based restoration.

In 2013, cooperating researchers including DNR, Virginia Department of Game & Inland Fisheries (VDGIF), Virginia Institute of Marine Science (VIMS), Virginia Commonwealth University (VCU), and University of Maryland Center for Environmental Science (UMCES), received a NMFS grant to support an acoustic tagging and telemetry project. The project will deploy and monitor a receiver array throughout the entire Chesapeake Bay. The standardized equipment is used by marine species researchers coast-wide and will detect any tagged species that interact with deployed receivers. Receivers will be deployed and monitored monthly. The data will provide information on sturgeon movements throughout the Chesapeake Bay and will support research efforts in other systems along the Atlantic seaboard.

DNR and our partners continue to work with ASMFC and NMFS to move forward with Atlantic sturgeon conservation efforts under the current ESA listing status. DNR will obtain a NMFS research permit to conduct spawning and physiology research. Target objectives are to maintain the existing captive brood stock, conduct research, and attempt to increase the captive population size and genetic diversity. The program goal is to develop all the tools and resources needed to supplement wild populations with hatchery-produced larvae and juveniles. Stocked fish could potentially serve management needs such as habitat suitability assessment and stock enhancement.

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