Shortnose Sturgeon Monitoring Program
As part of the cooperative sturgeon tagging program, 65 shortnose sturgeon, listed as endangered under the Endangered Species Act of 1973, have been reported in the Chesapeake Bay. In addition, 11 shortnose sturgeon have recently been captured in the Potomac River, a tributary to the Chesapeake Bay. Researchers are interested in finding out if there is a viable shortnose sturgeon population in the river.
Sturgeon in the Chesapeake Bay suffered intense fishing pressure in the late 1800's. Shortnose sturgeon were rarely distinguished from Atlantic sturgeon which makes determining the historic distribution and population size difficult. Maryland Fishery Resources Office (MFRO) continues to work on a project started in partnership with U.S. Geological Survey to determine if there is a spawning population of shortnose sturgeon in the Potomac River. In addition, researchers hope to learn more about the distribution and habitat preferences of this rare fish.
To collect information about the fish, gill nets are set at locations on the Potomac River where habitat appears to be suitable for shortnose sturgeon. Captured fish are tagged and radio-tracked to determine seasonal migration patterns and habitat preferences. If the radio-tagged sturgeon migrate upstream to spawn, nets are set below the spawning grounds to collect eggs and larvae.
In 2006, a radio tagged fish migrated upstream to the base of Little Falls at Chain Bridge. Although no eggs or larvae were recovered, biologists suspect that the fish moved upstream to spawn. In the second year of tracking two tagged fish, neither fish migrated upstream during spawning season. Sampling was conducted to collect eggs, larvae, and adult fish in the vicinity near Chain Bridge on the Potomac River but no additional life stages were recovered. The tagged sturgeon have also been tracked downstream to determine summer feeding areas as well as over-wintering habitat.
Biologists from the MFRO continue to track the tagged shortnose sturgeon and set gill nets in the Potomac River but it is still unknown whether the tagged sturgeon are members of a viable reproducing population, the last vestiges of a remnant population, or have recolonized the river by way of the Chesapeake & Delaware Canal. Continued research is needed to determine the status of shortnose sturgeon in the Potomac River.