ANNAPOLIS – The decades-old effort to restore the population of rockfish, one of the Chesapeake Bay’s most popular sport fish, is apparently finding success. State officials say the rate of successful spawning of rockfish, also called striped bass, is significantly above its 52-year average.
Eric Durell, a biologist with Maryland’s Department of Natural Resources, said the increase is not a fluke. “It’s what we’d hope to see,” he said.
It’s certainly an improvement over what they used to see. A complex index used to measure of the abundance of juvenile rockfish stood at 17.8 in 2005, well above the 52-year average of 12.0. The spawning index was at 5 or below for most of the 1980s.
A fishing moratorium in effect from 1985 to 1990, and then very conservative fisheries management afterwards, helped the species rebound, Durell said. Even now, striped bass fishing is subject to strict limits, related to the size of the fish and when and where they are caught.
Increased spawning will have benefits beyond Maryland’s borders, Durell said. “The Chesapeake Bay is a huge production site for the whole coast,” he said.
Rich Novotny, executive director of the Maryland Saltwater Fishermen’s Association, said the rockfish index shows what happens when you have good fisheries management.
Novotny, who has been fishing for striped bass for about 50 years, noted that only about 20 percent of the stock is being taken out each year now, in contrast to the 70 percent fishermen were removing before the moratorium. At the current rate, he said, “the stock is still rebuilding.”
William J. Goldsborough, a senior scientist at Chesapeake Bay Foundation, said the increased rockfish spawning is welcome news. “Since the moratorium in the 1980s, this population has come back like gangbusters,” he said.
Goldsborough said the credit does not just go to Maryland, however. Changes up and down the Atlantic coast helped turn things around. In some ways, the rebound is a good model for bringing back other species, he said, but it also offers cautionary lessons for other efforts since they “let the population virtually collapse in the ’80s.”
“Moratoriums are the blunt instrument of fisheries management,” Goldsborough said.
But now we know the spawning potential is there, he said, it’s time to turn our attention to other factors limiting the rockfish’s success, such as lack of its preferred food (menhaden), stress from the bay’s “dead zone” and disease.
Durell also noted that spawning was just part of the picture. “Large spawning population won’t guarantee a lot of fish,” he said. “You also need good weather in the spring,” among other factors.
In this year’s survey, DNR biologists collected 2,348 striped bass less than one year old. The Choptank River’s index was the highest since 2001. Striped bass reproduction in the upper bay and Potomac River was slightly above average. Reproduction in the Nanticoke River fell well below average.
Goldsborough and Durell both said these variations were normal, since local water quality and climate conditions fluctuate widely in the bay.
Other key species also turned up interesting results in the DNR survey. American shad reproduction was very high for the sixth consecutive year, particularly in the Potomac River. White perch reproduced at average levels throughout MarylandÕs portion of the Chesapeake Bay. Juvenile spot were very abundant as far north as the Susquehanna Flats. DNR biologists found a modest increase in juvenile Atlantic menhaden, but spawning success is still well below 1970s levels. DNR scientists have monitored the spawning success of striped bass and other species in the Chesapeake Bay since 1954. There are survey sites in the four major spawning systems: the Choptank, Potomac, and Nanticoke rivers, and the upper bay. Biologists visit each site monthly from July through September, collecting samples with two sweeps of a 100-foot net called a beach seine.