From the New York State Department of Environmental Conservation
Each year, DEC biologists monitor both the juvenile and spawning adult populations of Atlantic sturgeon, one of the Hudson River’s most iconic fish species. These long-term monitoring programs were developed to track the Hudson River Atlantic sturgeon population following the commercial fishery closure in 1996 due to a declining population.
Since the mid-2000s, DEC’s Hudson and Delaware Marine Fisheries Unit has been monitoring the abundance of juvenile Atlantic sturgeon at their overwintering area in Haverstraw Bay. From late February to the end of April, young Atlantic sturgeon are collected using nets at their overwintering area in Haverstraw Bay. The sturgeon are weighed, measured for length, and examined for previous tags. Untagged fish are tagged under the dorsal fin with a Passive Integrated Transponder or PIT tag. This tag is like a microchip put in pets and is about the size of a grain of rice.
Likewise, each June fisheries biologists use much larger nets (even bigger than the mesh of soccer nets) to monitor the size and sex composition of the adult spawning stock near Hyde Park. Adult sturgeon are processed in a similar fashion as the juveniles. However, the sex of the fish can be determined through the expression of milt or eggs, as individuals are mature and are in spawning condition. The adults also are scanned for a PIT tag. These PIT tags help managers and researchers learn more about sturgeon movement and behavior while in the Hudson. The tags also can be scanned and detected by other scientists in other rivers along the East Coast. Atlantic sturgeon migrate as far south as Georgia and as far north as Canada’s Bay of Fundy, so the tags give scientists clues about where sturgeon migrate from place to place. Lastly, the tags can help learn about reproduction, survival, and population recovery.
Young Atlantic sturgeon spend up to five to seven years in the freshwater Hudson before moving into the ocean to migrate along the east coast. They are also a late maturing species and females may not spawn for the first time until the age of 15. Therefore, protected sturgeon spawned after the 1996 moratorium would only begin to return and spawn in the Hudson River in the early 2010s.
Through DEC’s long-term monitoring of both juvenile and adult sturgeon, DEC biologists are now seeing sturgeon originally PIT tagged as small toddlers returning to spawn as massive adults. Thus far, seven adult sturgeon have been recaptured on the spawning grounds after being at large for as long as 14 years. In 2023, three adults (two originally tagged in 2009 and one in 2011) were recaptured having grown between approximately a meter to 1.5 meters in length! Biologists hope to see an increasing trend in the number of adults that were originally tagged as juveniles returning to spawn in the Hudson River. This would signify the 1996 moratorium and other protection measures are benefiting the species and adult sturgeon are returning to produce more offspring that will overwinter in Haverstraw Bay and ultimately return again as adults.
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