Results signal benefits for future fisheries
Preliminary results from an ongoing long-term survey conducted by researchers at the Virginia Institute of Marine Science (VIMS) suggest an average class of young-of-the-year striped bass was produced in Virginia tributaries of Chesapeake Bay in 2014. The 2014 year class represents the group of fish hatched this spring that will grow to fishable sizes in 3 to 4 years.
The program, formally known as the Juvenile Striped Bass Seine Survey, recorded slightly more than 11 fish per seine haul, which is statistically equivalent to the historic average of about 9 fish per seine haul. This year represents the second consecutive year of average annual recruitment for striped bass in Virginia waters of Chesapeake Bay. Like many other fishes, striped bass exhibit considerable variation in recruitment from year to year.
Striped bass spawning biomass, a measure of adult fish that return to spawn each spring, is traditionally dominated by a few strong year classes. For instance, striped bass recovery in the mid 1990s was partially attributed to a few strong year classes produced in the late 1980s. Striped bass populations, and the fisheries they support, are stabilized by strong year classes that can mitigate the effect of less-productive years. The return of the juvenile abundance index to average levels in 2013 and 2014 suggests that adult striped bass abundance may appear less variable once these cohorts join the population. Although the 2014 year class of striped bass is considered average in terms of abundance, it represents a significant increase following the below-average recruitment observed in 2012.
Striped bass play an important role as a top predator in the Chesapeake Bay ecosystem and provide value to numerous commercial and recreational anglers. The economic and ecological value of striped bass lends significant interest to the year-to-year status of their population. By estimating the relative number of young-of-year striped bass, the Juvenile Striped Bass Seine Survey provides an important measure of annual and long-term trends in the Bay's striped bass population.
The VIMS Juvenile Striped Bass Seine Survey currently samples 18 stations in the Rappahannock, York, and James River watersheds. Biologists sample each site five times from early July through mid-September of each year. At each site, they deploy a 100-foot seine net from the shore and count and measure every netted fish before returning them to the water. These young striped bass generally measure between 1.5-4 inches (40 and 100 mm). Survey scientists in Virginia measured 2,293 juvenile striped bass at these stations in 2014. VIMS has been conducting the survey annually since 1967 for the Virginia Marine Resources Commission.
The Bay's striped bass population has rebounded from historic lows in the late 1970s and early 1980s, following fishing bans enacted in Delaware, Maryland, and Virginia in the mid- to late-1980s. Since then, the Bay's striped bass population has increased to the point that striped bass are now considered recovered. Monitoring of juvenile striped bass recruitment will continue next year to provide managers with crucial information to sustainably manage this sentinel Bay species.
For more information about the Virginia Juvenile Striped Bass survey visit the survey's webpage at http://www.vims.edu/research/departments/fisheries/programs/juvenile_striped_bass/index.php
Information about a similar survey conducted by the Maryland Department of Natural Resources for striped bass populations in the Maryland portion of Chesapeake Bay can be found at http://news.maryland.gov/dnr/2014/10/15/striped-bass-survey-reveals-healthy-2014-reproduction-2/