Striped bass are often seen as the greatest success story of the Chesapeake Bay. Populations of this iconic sport fish plummeted in the 1970s and early 1980s, but then rebounded between 1985 to 1990 thanks to tightened catch restrictions in a dozen states, including a moratorium on catching them in Maryland, Virginia, and other states.
A New Decline
Today, we face a new decline, albeit one that has not taken "stripers" anywhere near as low as last time. According to the latest science developed by the Atlantic States Marine Fisheries Commission—a regional fisheries management board—the Atlantic striped bass stock (which includes populations from the Bay and Delaware and Hudson Rivers) has been declining since 2004 when it was at an all-time peak. Concurrently, recreational catches have dropped steadily, especially at the edges of the range of the species in New England and North Carolina—shrinking of a fish's range is a sure sign of decline in the population. To protect this important species and reverse the decline, starting in 2015 the commission reduced the allowable catch of striped bass by up to 25 percent. Find out more about the current state of the menhaden fishery.
Water Pollution and Poor Diet
Water pollution and poor diet may be partly to blame for the recent decline in striped bass. "Significant concerns remain about their favorite food, menhaden, which have been experiencing lower recruitment in the Bay for over 20 years," said CBF Senior Scientist Chris Moore.
So where is the striped bass' food—these smaller fish, the menhaden—going? Many are being caught by an industrial fishing fleet out of Virginia, which processes them to make fish feed, fish oil pills, and other products. Virginia is the only state on the coast that still allows this industrial fishing.
Without enough nutrients from menhaden, and stressed by poor water quality, some scientists believe the immune systems of striped bass are becoming suppressed. The theory is that weakened disease-fighting systems make stripers more likely to become ill with a chronic wasting disease called mycobacteriosis, which infects as much as 70 percent of the Bay's striped bass.
The disease is caused by bacteria that are found nearly everywhere in the water and sediment, said Dr. Wolfgang Vogelbein of the Virginia Institute of Marine Science. "We feel that these environmental bacteria…are opportunists, and that disease outbreaks are stress-related," said Dr. Vogelbein, who discovered mycobacteriosis in striped bass in 1997. His lab is now studying the possible link between mycobacteriosis, stress in fish, and low-oxygen "dead zones," often caused by pollution.