BOSTON (AP) – Environmentalists seeking to protect one of New England’s most popular sport fish have asked regulators to close waters off Cape Cod to fishing trawlers if they accidentally catch too many striped bass.

The environmental group Oceana petitioned Tuesday for an emergency rule that would shut down an area directly east of Cape Cod known as the Great South Channel between Sept. 1 and Nov. 1 after 289,000 pounds of bycatch is recorded. Bycatch is fish unintentionally caught, then thrown away.

The striper stock is healthy after rebounding in recent decades from a crash, but Oceana’s Gilbert Brogan said bycatch could undermine the gains.

Oceana’s proposed limit is based on a federal striper bycatch estimate for the 2002 fishing year, released in June. The report said 84 percent of the bycatch occurred between September and October, when the fish are migrating through the channel.

The problem is largely isolated in a time and area, so the limit could stop damage until a long-term solution is found, Brogan said. Fishermen won’t like it, he acknowledged.

“If this limit is enforced, maybe they’ll change their behavior,” he said. “All we’re asking is that they do better.”

Robert Lane of the New Bedford-based Trawlers Survival Fund said the striper limit would have no affect on fishermen because there’s little striper bycatch. “Once in a while, you see a handful,” he said.

“(Oceana is) not doing anything for anybody or any fish,” Lane added. “It’s just to keep the money coming into their coffers.”

Striped bass rebounded after bottoming out in the early 1980s after federal waters were closed to striper fishing and states adopted stricter limits. Sport fishermen grew passionate about protecting the stripers, which are both feisty and tasty.

In 2002, the most recent year for which figures are available, about 24.5 million pounds were landed along the Atlantic Coast, about 75 percent by recreational fishermen.

Striper bycatch isn’t tracked federally or by states. In March, Oceana estimated that between 1.4 and 2.4 million pounds of striped bass bycatch was caught annually. The federal estimate is far lower than Oceana’s, but Brogan said even the lower amount could hurt.

Oceana’s petition was sent to the National Marine Fisheries Service and the New England Fishery Management Council, a regional advisory body. Aside from the limit, Oceana requested more observers on fishing boats to better record bycatch.

Teri Frady, a spokeswoman for the National Marine Fisheries Service, said the agency received the petition and would consider it.

“We would be interested in all sources of discard, not just related to trawlers,” she said.