DNR Release 2013 Young-of-the-Year Striped Bass Survey
10/18/2013 | Posted by kkingTags: Striped Bass
Spawning success increases over last year but remains below average
The Maryland Department of Natural Resources today announced that the 2013 Striped Bass juvenile index - a measure of Striped Bass spawning success in Chesapeake Bay - is 5.8, a substantial increase over last year's results of 0.9, but below the 60-year average of 11.7. The survey is conducted to track the reproductive success of Maryland's State Fish, which is known to be highly variable from year to year.
"Several years of average reproduction mixed with large and small year-classes are typical for Striped Bass," said DNR Fisheries Director Tom O'Connell. "For example, as recently as 2011, we saw the fourth-highest spawning success in the survey's history."
Striped Bass spawn in the spring when individual females produce millions of eggs. The survival of eggs and larvae is largely influenced by environmental factors such as water temperature, salinity and flow rates.
Through the Atlantic State Marine Fisheries Commission, Maryland works with state and federal partners to protect and manage the Striped Bass population. Each year, the Commission assesses Striped Bass spawning success by evaluating juvenile index survey results conducted along the Atlantic coast. Three continuous years of poor recruitment, as defined by the Commission, would trigger a review of management actions. Maryland's 2013 Striped Bass juvenile index did not fall below the poor recruitment line. Three consecutive years of poor recruitment has not been experienced in Maryland since the mid-1980s due to the success of coastal management efforts.
The Commission also conducts a comprehensive assessment of the entire stock every 1-2 years to determine whether changes in management strategies are needed to ensure a healthy population and fishery. The most recent stock assessment will be reviewed by the Commission later this month.
During this year's survey of juveniles, biologists counted more than 34,000 fish of 51 different species, including 759 juvenile Striped Bass, at 22 major sites in the four major spawning systems - the Choptank, Potomac, and Nanticoke rivers, and the Upper Bay. DNR biologists visited each site monthly from July through September, collecting fish samples with two sweeps of a 100-foot beach seine. Juvenile indices are calculated as the average catch of young-of-year fish per sample.
The agency uses these data to assess spawning success of other important species. American Shad reproduction was very successful - approximately four times the long-term average - particularly in the Potomac River and White Perch experienced near-average reproduction. DNR has monitored the reproductive success of Striped Bass and other species in Maryland's portion of the Chesapeake Bay annually since 1954.
The Virginia Institute of Marine Science (VIMS) conducts a similar survey in Virginia's portion of the Bay, which can be viewed here.
Graph Showing Annual Striped Bass Juvenile Results Dating Back to 1956 (click to enlarge):