Striped Bass (Rockfish)
Photo by Blair M. Seltz/CBF Staff
Preventing Another Striped Bass Collapse
Striped bass are often seen as the greatest success story of the Chesapeake Bay. Populations of this iconic sport fish plummeted in the early 1980s, but then rebounded because of tightened catch restrictions in a dozen states from 1985 to 1990, including a moratorium on catching them in Maryland.
A Possible New Decline
Today, "stripers" are still relatively numerous—but there are warning signs of a possible new decline. According to the Atlantic States Marine Fisheries Commission—a regional fisheries management board—recreational fishermen have experienced a two-thirds drop in striped bass catches since 2006.
To protect this important species, the commission recently voted to consider a reduction in the allowable catch of striped bass by up to 40 percent in 2012.
CBF Senior Fisheries Scientist Bill Goldsborough, who serves on the commission, said that such limits would be a wise move. He said the Atlantic states need to move beyond the "wait-for-a-crisis" style of fisheries management that allowed the rockfish crash in the early 1980s and instead adopt a preventative style.
Water Pollution and Poor Diet
Goldsborough explained that water pollution and poor diet may be partly to blame for the recent decline in striped bass. "Their favorite food, menhaden, is at an all-time low, and that appears to be causing problems that we see in the Chesapeake's resident striped bass," Goldsborough said. "They’re skinny, they're diseased, and they're dying at a faster rate, in part because they are not getting enough good nutritious food to eat."
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 livestock and fish feed, fish oil pills, and other products. Virginia and North Carolina are the only two states in the East that still allow 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.
Preventing Another Crash
Tom O'Connell, Fisheries Director for the Maryland Department of Natural Resources, noted that the Atlantic states are also considering limits on catching menhaden as a way to prevent another striper population crash.
"The last thing we want to do is get back into a situation where we are faced with a moratorium. Nobody wants to do that," O'Connell said. "Some modest adjustments today would help avoid future significant actions."
In other words, an ounce of prevention is worth a ton of sustainable fishing.