Striped bass—also known as rockfish or stripers—have been one of the most sought-after commercial and recreational fish in the Chesapeake Bay since colonial times. After bouncing back from a severe decline in the 1970s and 1980s, the striped bass population is now at its highest level in decades. However, scientists are uncertain about the health of the species because of a high prevalence of disease and possible lack of prey.
Why are striped bass important?
Striped bass are a key predator in the Chesapeake Bay food web. They also support one of the Bay's most popular commercial and recreational fisheries.
Striped bass are one of the top predators in the Chesapeake Bay food web. As a result, they must have enough prey—primarily menhaden and bay anchovies—available to them to keep their population healthy and the food web in balance. Strong fluctuations in the number of striped bass in the Bay could cause cascading changes throughout the rest of the food web.
Striped bass is the most important commercial and recreational fish species in the Chesapeake Bay. Its size, fighting ability and delicious taste makes rockfish one of the top sport fish in the Bay and on local restaurant menus.
Striped bass is so acclaimed in the Chesapeake Bay region that the Maryland General Assembly designated it the Maryland state fish in 1965, writing:
“Whereas, The people of Maryland as long time and appreciative residents of the productive Chesapeake Bay area know of it first hand the recreational and gastronomic delights of this wonderful land, and
Whereas, Not the least among the good reasons for living in Maryland is the abundant and unexcelled delicacy of the Chesapeake Bay striped bass or rockfish, and
Whereas, In the judgment of the members of the General Assembly of Maryland, it is a simple act of justice and of equity that this fine old Maryland fish should be honored by being designated as the official fish of the State of Maryland...”
Why did striped bass numbers decline in the 1970s and 1980s?
The striped bass fishery experienced record-high catches in the early 1970s; in 1973, the commercial fishery landed 14.7 million pounds. But following that year, reported commercial and recreational catches declined steeply. By 1983, the striped harvest had fallen to just 1.7 million pounds.
The reasons for the sharp decline in striped bass harvest during the 1970s and 1980s were complex. Scientists primarily attributed it to overfishing, which may have made striped bass more susceptible to pollution and other stresses, including:
- Water temperature fluctuations in spawning grounds.
- Low dissolved oxygen in deeper Bay waters, which eliminated much of the fish's summer habitat.
- Acidity and chemical contaminants in certain spawning areas.
- Poor water quality from runoff from the land and sewage treatment practices.
In response to this downturn, Congress passed the Atlantic Striped Bass Conservation Act in 1984. Maryland and Delaware imposed fishing moratoria on striped bass from 1985 through 1989, and Virginia imposed a one-year moratorium in 1989.
The Chesapeake fishery reopened in 1990, after three-year average recruitment levels exceeded an established threshold value. Since that time, the striped bass population in the Bay has dramatically increased, likely because of responsible, adaptive management coast-wide and suitable environmental conditions. In 1995, the population had increased to the point where striped bass was considered restored, and catches have remained stable since.
What issues currently threaten striped bass?
Scientists are concerned about the high prevalence of a disease called mycobacteriosis among Bay striped bass. Since the late 1990s, researchers have documented an increased occurrence of external lesions associated with mycobacteriosis on striped bass. This persistent episode of lesions has led to questions about:
- The effects of the disease on the striped bass population.
- Environmental conditions surrounding the increased prevalence of disease.
- The diminished nutritional state of the fish for recreational anglers and commercial fishermen.
- The ecology of disease.
In 2015, Maryland striped bass disease monitoring data was used to investigate the potential connection between mycobateriosis and environmental conditions such as water quality. Findings of the study suggest that the proportion of fish that test positive for the disease is correlated with water quality, and that the prevalence of mycobateriosis seems to increase as nitrogen, phosphorus and sediment pollution increases.
Most theories about the current health of Bay striped bass are associated with the fish's increased abundance since moratoria were lifted in 1990. In particular, researchers are concerned about whether there is enough prey to adequately support the large striped bass population. Prey availability is an important factor in striped bass abundance and growth. Some believe that conservative management of striped bass, in combination with harvest of principle prey species, such as Atlantic menhaden, may be leading to a lack of food and slower growth rates in striped bass.
How are striped bass managed?
The recent history of striped bass in the Bay—full population restoration after steep declines in the 1970s and 1980s—represents a management success story. However, the current status of Bay striped bass—high abundance but uncertain health—illustrates the need for fisheries managers to take an ecosystem-based approach for their future existence. Continuing research and restoration efforts remain critically important to the future of the species, as the Bay is the primary spawning and nursery area for 70 to 90 percent of the Atlantic striped bass stock.
A coast-wide fishery management plan (FMP), from Maine to North Carolina, is in effect for striped bass under the Atlantic States Marine Fisheries Commission (ASMFC). The primary objective of the Bay Program's 1989 striped bass FMP is to follow ASMFC annual guidelines and requirements, including:
- Controlling fishing mortality.
- Developing regulations to allocate and control safe harvest levels.
- Determining stock assessment and research needs.
- Examining the effects of environmental conditions, such as habitats and water quality, on striped bass stocks.
Combined commercial landings of striped bass from Maryland and Virginia, as well as reported coast-wide recreational catches, have remained stable since the mid-1990s.
Bay managers are currently developing an ecosystem-based FMP for striped bass. Rather than the current single-species approach, ecosystem-based FMPs take into account a fish species' whole ecosystem, such as interactions with other species and pollution and other stressors.
One benefit of creating an ecosystem-based striped bass FMP is to better understand—and then manage for—predator-prey interactions. Striped bass are recognized as one of the top predators in the Bay, impacting forage species like Atlantic menhaden, an ecologically and commercially important species. Ecosystem-based FMPs will make sure that these two interdependent species have compatible management objectives.
For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.
To protect striped bass, make sure to follow proper fishing regulations. You can also help keep striped bass and other aquatic animals healthy by preventing pollution from entering local waterways: install a green roof, rain garden or rain barrel to capture and absorb rainfall; use porous surfaces like gravel or pavers in place of asphalt or concrete; or redirect home downspouts onto grass or gravel rather than paved driveways or sidewalks.