Sturgeon Research and Conservation in the United States
PIs: Dan Erickson, fisheries consultant, and Dr. Phaedra Doukakis, Institute for Ocean Conservation Science
Sturgeons have inhabited the earth for more than 200 million years, but in the last century have suffered a devastating population decline. Highly valued for their prized caviar eggs, sturgeons have been decimated by overfishing, water pollution, and the construction of dams that block their spawning routes. This animal continues to struggle to reach sustainable population levels despite bans on fishing for most sturgeon species in the United States.
The Institute for Ocean Conservation Science has been a leader in research initiatives to learn more about sturgeons’ migratory behavior within the United States and inform the best possible recovery and conservation plans for two native species: Atlantic sturgeon, which inhabit east coast waters, and green sturgeon, which live in west coast waters. An understanding of the species’ population distribution and movement are essential to effectively minimize threats to the species’ survival.
All species of sturgeon spawn in freshwater rivers, and many then return to the ocean or sea to live the majority of their lives. Our scientists have spent days at a time on rivers where sturgeon spawn, searching for and capturing the fish, affixing electronic tags to each animal to track its elusive movement patterns, and then releasing the sturgeon back into the river. These “pop-up archival tags” gather data as the fish moves, and communicate it to satellites and data receivers, providing an invaluable, detailed map of wild sturgeon’s migration routes and habitat use. They record information as precise as the exact date a sturgeon left a river or entered a bay, the fish’s swimming depth, and the fish’s preferred water temperatures.
The Institute team has successfully tagged more than 50 east coast sturgeon in recent years, working in the two rivers that support the nation’s largest Atlantic sturgeon spawning populations -- the Hudson River in New York, and the Altamaha River in Georgia. Fisheries consultant Dan Erickson and collaborators from the New York State Department of Environmental Conservation, the U.S. Fish and Wildlife Service, the University of Georgia, and the Wildlife Conservation Society (WCS) have together been able to shed more light on the fishes’ movements within and between the river and ocean, and pinpoint the threats they face along the way in each environment. Our collaboration on these initiatives with scientists from Maine to Florida has greatly expanded our geographic monitoring capacity and allowed us to gain an increased understanding of these species’ range of movement. This information has been collectively used to understand the habitat needs of these prehistoric animals and ultimately inform conservation plans that will better protect them.
The Institute has also worked diligently to learn more about green sturgeon on the west coast, and to foster their recovery. Erickson and Dr. Phaedra Doukakis of the Institute for Ocean Conservation Science have collaborated with the Oregon Department of Fish and Wildlife, the National Oceanic and Atmospheric Administration, and WCS to launch the first effort aimed at describing the movements of green sturgeon, the threats they face, and the number of spawning adults that remain. Our scientists since 2000 have studied green sturgeon in Oregon’s Rogue River, one of only three rivers in the world where green sturgeon spawn. By tagging and tracking these fish, our team has been able to identify the migratory patterns of green sturgeon and the threats they encounter along their routes of travel. These invaluable insights have and will be used to reduce the species’ fishing mortality, develop large-scale monitoring plans, and educate the public about the importance of sturgeon conservation. The data obtained from this research will be also be used to strengthen federal rules guiding the conservation and restoration of green sturgeon, which are listed as a Threatened under the U.S. Endangered Species Act.
Tagging a sturgeon is an adventurous and labor-intensive undertaking. Each massive fish must be captured in a net, one at a time. Once hauled on board, the sturgeon is placed into a large sling, where it is kept stationary while scientists surgically implant a tag and then suture the fish’s incision. Getting each sturgeon onto a boat often requires the muscle of several people working together: consider that several Atlantic sturgeon caught to date have exceeded 250 pounds and 8 feet in length. (The largest Atlantic sturgeons on record exceeded 800 pounds and 14 feet in length).
Not only does studying sturgeon take strength and skill, but it also takes patience. Sturgeon are not easy to come by. Although Atlantic sturgeon still inhabit more than 30 rivers along the east coast of North America, overfishing and habitat destruction have led to a severe decline in their abundance. Approximately 38 rivers supported spawning populations in the late 1800s and early 1900s. Now, sturgeon spawn in only 20 North American rivers.