Striped Bass

The Chesapeake is a magnet for striped bass, Morone saxatilis — or rockfish as we locals call them. Some 70 to 90 percent of the entire Atlantic stock that ranges from Canada to Florida are spawned in the Bay.

Like salmon, striped bass spend much of their lives in the ocean, but they journey back to their home rivers to spawn. This makes stripers anadromous, as opposed to species that spawn in seawater, like bluefish, which are catadromous.

Striped bass play a big role in the Chesapeake Bay’s food web. Throughout the year adult striped bass eat a host of fish species, including menhaden, Bay anchovy, Atlantic croaker, and white perch, as well as crabs and other organisms. Juveniles feed on larval fish and insects, and small crustaceans.

The Fishery

Tasty and spirited, striped bass appeal to commercial and recreational fishermen alike. After bountiful catches in the 1970s, a string of low harvests and a declining stock led authorities to ban fishing in a number of Maryland rivers during the spring spawning run. Recognizing the severity of the situation, in 1984 Congress passed the Atlantic Striped Bass Conservation Act. Maryland and Delaware responded by imposing a fishing moratorium lasting from 1985 until 1990 — for five years no one in those states could catch or even possess striped bass.

Over the course of the moratorium scientists and managers gathered valuable information on the species and how best to conserve it in the future. It was determined that overfishing had decreased the stock and left the striped bass population more susceptible to stressors such as poor water quality and loss of habitat. When fishing resumed, managers set conservative harvest limits based on an annual juvenile index to ensure that the stock would rebound. By 1995, the Atlantic States Marine Fisheries Commission declared the stock restored.

Disease

Rebounding from a threatened species to an abundant one, the striped bass is often championed as a fisheries management success story. Yet despite the stock’s abundance, the Chesapeake’s striped bass still faces difficulties, including changes in the Bay’s food web and the threat of disease. Since 1997, a bacterial infection called mycobacteriosis has plagued many striped bass in the Bay. The disease, which causes lesions and internal growths, had previously occurred more frequently in cultured stocks. As more of the wild stock become infected, scientists grapple with numerous questions for which there are few clear-cut answers. How is the disease transmitted? Why does the bacterium cause disease in some fish, but not in others? And perhaps most importantly, why are striped bass as a population susceptible to disease? While some scientists suggest that poor water quality and decreases in prey may stress the Bay’s striped bass, making them more vulnerable to disease, research continues to probe these and other potential causes.

Maryland Sea Grant Research

For over two decades, Maryland Sea Grant has supported striped bass research, particularly as it applies to aquaculture. As a fledgling industry, striped bass aquaculture has faced several challenges, including difficulty in spawning fish year round and in breeding for particular traits such as faster growth and disease resistance. Sea Grant has funded numerous research projects addressing these issues and more, including: protection against disease, induced spawning, larval nutrition in hatcheries, and improved growth rates. Additionally, Sea Grant has funded research on striped bass and low dissolved oxygen and food web (trophic) interactions, water quality and fish production, and algae blooms and fish recruitment. This research has led to insights into the biology of both cultured and wild stocks of this valuable species.