Certain stocks of the Atlantic striped bass in North Carolina have continued to dwindle because of fishing pressure, pollution, and loss of habitat. In addition, roadblocks such as dams have made it difficult for the bass to make their way up river to traditional spawning grounds.
The Wilmington District and stakeholders have found a creative solution to help sustain the Atlantic striped bass population and other fish species. The bass is an anadromous fish which means it’s born in fresh water, makes its way down river and lives most of its life in salt water. It eventually returns to traditional fresh water spawning grounds. At Lock and Dam 1 on the Cape Fear River the fish will soon be able to swim over the dam. Contractors continue to place large beds of rock at the base of the dam to mimic natural rapids so that the bass can swim upstream.
“They’re a very important fish which is why we’re looking at increasing fish passage at the locks and dams,” said Wilmington District biologist Frank Yelverton. “The striped bass are at the top of the food chain. It’s crucial that the striped bass reaches its tradition spawning grounds.”
Yelverton explained that the rapids at Lock and Damn #1 is the first step in alleviating the need for locking the fish past the Wilmington District’s three locks and dams on the Cape Fear River. He said that If only 50 percent of the fish can make it through Lock 1 by currently locking the fish, then 50 percent of that group will make the next locking gate. If 50 percent of those remaining fish make it through the next lock then only 10 to 15 percent of the entire population going upstream can make it to the traditional spawning grounds.
“There are more than 30 of these rock-rapid structures in the U.S.,” Yelverton said. “They have all shown that fish can pass, even lake sturgeon. The first step in the process is to fill in the scour hole which strengthens the stability of the dam. The second portion is adding more rock to provide a flat surface for the striped bass, shad and sturgeon to go over. That will start in June and take a couple of years to complete. It will average about a four percent slope, and it will mimic natural rapids so that the fish can swim upstream and not even know that a dam is right there. When they come to the rapids they’ll just swim right over the dam. By locking them through you’d have to wait for the fish to congregate.”
Along the lower Roanoke River in northeast North Carolina, the Wilmington District and stakeholders have developed another way to help sustain the Atlantic striped bass population during spawning. Water at John H. Kerr Dam and Reservoir is strategically stored, then released during the April through mid-April through June spawning period.
“We store that extra water in the spring, and then release it in coordination with the fish agencies as far as the best timing and magnitude of releases to coincide with spawning,” said Wilmington District Chief of Water Management Tony Young. “Over the last 10 or more years we’ve seen a very positive rebound in the population of the striped bass. The fisheries biologists sample the striped bass population every year and they are satisfied with the populations that they’ve been recording.”
Young says this extra storage and coordination with agencies helps to avoid impacts to other project purposes such as hydropower and recreation, while providing beneficial downstream flows for the bass population. Constant dialogue with the fisheries ensures that.
“We do a weekly energy declaration and coordinate with the fisheries to see exactly how much energy to declare. This translates into how much water gets released. So we work very closely with them during the spawning season. All the reports that we’ve seen indicate that these managed releases for the fish have really helped improve the population of striped bass in the Roanoke River.”