Surveys of juvenile striped bass in the Chesapeake Bay watershed found lower numbers of fish in 2023. Conducted by biologists in Maryland and Virginia, the surveys included counts of juvenile striped bass and other species in waters of the Chesapeake Bay.
In Maryland, the 2023 young-of-year index is 1.0, well below the long-term average of 11.1, according to Maryland Department of Natural Resources (DNR).
“The warm, dry conditions in winter and spring during the past several years have not been conducive to the successful reproduction of fish that migrate to fresh water for spawning,” said DNR’s Fisheries and Boating Director Lynn Fegley. “In response, we’re working with the Atlantic States Fisheries Commission to support management actions we can take now to protect striped bass and improve spawning success. The Department is also considering additional state-specific actions to increase protections within Maryland.”
Efforts to rebuild the Atlantic Coast population have been underway for several years and are ongoing. Low levels of spawning stock in recent years have spurred action by the Atlantic States Marine Fisheries Commission, which manages the overall population of striped bass along the Atlantic coast, including the Chesapeake Bay.
In May, the Commission put in place an emergency measure that bars anglers from harvesting fish larger than 31 inches. In early 2024, the Commission will vote on additional regulation changes aimed at reducing striped bass deaths caused by coastwide fishing activity, including the Chesapeake Bay.
In previous years, Maryland has taken several management actions aimed at rebuilding the spawning stock; including a recreational one-fish daily catch limit, a two-week summer closure, changes in slot size, and moving season start and end dates. In addition to fishing pressure, biologists suspect that changing environmental conditions may be hindering striped bass populations in the Chesapeake Bay watershed.
Striped bass spawning activity is temperature-driven and historically adult fish migrated to the Chesapeake Bay to spawn in April and May, which aligned with the seasonal arrival of zooplankton and other microscopic food sources that larval striped bass eat. However, recent winters have produced less-than-average snowfalls in the region and therefore less snowmelt to cool the rivers and streams where striped bass spawn.
Research has also shown Spring zooplankton production in the Bay is being altered by warmer winters. Fishery scientists are continuing to investigate whether higher temperatures earlier in the year are affecting the survivability of juvenile striped bass.
Despite the challenges striped bass face, historic spawning data have shown the ability of the overall striped bass population to increase quickly under the right environmental conditions. The species can have several years of poor recruitment followed by a productive spawning year that can bolster the overall population long-term.
Previously, favorable environmental conditions for striped bass such as heavy winter snowfalls or higher spring rainfalls have helped produce stronger juvenile year classes. Nutrient pollution reduction efforts throughout the Bay watershed have also reduced the instances of hypoxia affecting striped bass and other fish.
Biologists captured more than 47,000 fish of 63 different species while conducting this year’s survey. Other anadromous species with similar spawning behavior also experienced below-average reproduction this year, including white perch, yellow perch, shad, and herring.
Encouraging results were documented regarding two species lower on the food chain. Menhaden abundance was the highest measured in over 30 years. Bay anchovy abundance was the highest measured since 1974.
During the annual Maryland survey, fishery managers examine 22 sites located in four major striped bass spawning areas: the Choptank, Nanticoke, and Potomac rivers, and the Upper Chesapeake Bay. Biologists visit each site three times per summer, collecting fish with two sweeps of a 100-foot beach seine net. The index represents the average number of recently hatched striped bass captured in each sample.
Preliminary results from an ongoing long-term survey conducted by researchers at the Virginia Institute of Marine Science suggest a poor year class of young-of-year striped bass was produced in Virginia tributaries of the Chesapeake Bay in 2023. The 2023 year class represents the group of fish hatched this spring that will grow to fishable sizes in three to four years.
The VIMS Juvenile Striped Bass Seine Survey recorded a mean value of 4.26 fish per seine haul in the Virginia portion of the Chesapeake Bay; this value is called a recruitment index by scientists. The 2023 value is significantly lower than the historic average of 7.77 fish per seine haul and is a notable decrease in annual recruitment compared with recent years in which catches of striped bass were rated average or above average.
Poor recruitment during 2023 is consistent with patterns observed by the long-term monitoring program. Since the lifting of the striped bass fishing moratorium in 1990, single years of low recruitment have occurred approximately every ten years in Virginia waters, the last occurring in 2012. However, striped bass recruitment can vary considerably from year to year. Poor recruitment in 2012 was followed by 10 years of average to above-average recruitment.
Striped bass spawning biomass, the adult stock which returns to spawn each spring, is traditionally dominated by a few strong year classes. If three continuous years of poor recruitment are documented, management actions will be triggered to identify and address issues of striped bass spawning success.
The VIMS survey samples 18 index sites in the Rappahannock, York, and James River watersheds. Biologists sample each site 5 times from mid-June to early September, deploying a 100-foot seine net from the shore. Each fish captured in the net is counted, measured, and returned to the river. These young striped bass usually measure between 1.5 and 4 inches. Survey scientists in Virginia measured 1,025 juvenile striped bass at these stations in 2023. VIMS has been conducting the survey annually since 1967 for the Virginia Marine Resources Commission.
The striped bass population in Chesapeake Bay has rebounded from historic lows in the late 1970s and early 1980s after fishing bans were enacted in Delaware, Maryland, and Virginia in the mid- to late-1980s. Since then, the population increased to the point that striped bass in the Bay and elsewhere were considered recovered.
In 2019, scientists determined that the striped bass population was overfished and that mortality due to fishing was higher than what the population can withstand in the long term. The Atlantic striped bass stock remains overfished but are no longer experiencing overfishing based on the 2022 Atlantic Striped Bass stock assessment update.
In the Chesapeake Bay region, striped bass are also known as rockfish. The species is important to both recreational and commercial fishermen.
sources: Maryland Department of Natural Resources, Virginia Institute of Marine Science