WASHINGTON (AP) _ They're not your usual constituent group, but sea turtles are among those living in this country - or off its shores - who will be affected by House consideration of the $11 billion supplemental appropriations bill.

Wedged into the measure, which lawmakers began considering today, is language that would block the government from requiring the nation's shrimp fishermen to install metal devices in their nets to help free ensnared sea turtles.

The provision received a boost today when one of its leading opponents, Rep. Gerry Studds, D-Mass., said he would not try to strip it from the overall legislation.

The sea turtle provision is pitting shrimpers against environmentalists. The shrimpers say the new equipment would reduce their catch and cost hundreds of dollars to install, while the environmentalists argue that 11,000 of the creatures die each year in shrimp nets.

The focus of the measure is a contraption the government has dubbed turtle excluder devices, or TEDs. Shrimpers, who say the equipment makes it harder for their boats to catch their prey, have renamed the acronym the trawler excluder device.

All five species of American sea turtles, some of which weigh more than half a ton, are protected under the Endangered Species Act. Their numbers dropped in recent decades as their nesting beaches were developed and their eggs were hunted, often in a belief that they are aphrodisiacs.

Most seriously diminished have been the Kemp's ridley turtle, with only an estimated 570 mature females surviving.

''I think sometimes the shrimpers lose sight of that fact, that this legislation was passed to protect the diversity of life on this planet,'' says Marydele Donnelly, director of the Sea Turtle Rescue Fund, a part of the Center for Environmental Education in Washington. ''They're being short- sighted.''

But Wilma Anderson of Aransas Pass, Texas, owner of three shrimp boats and a director of Concerned Shrimpers of America, counters, ''We can't live with those regulations. When you're starting to take a man's sole livelihood away from him, they better understand why that man is coming back fighting.''

The National Marine Fisheries Service has proposed regulations that, beginning July 15, gradually would require the use of TEDs. By 1989, most shrimpers from North Carolina to Texas using nets at least 30 feet wide would have to use them.

Rep. Bob Livingston, R-La., a candidate for governor, has responded to protests registered by shrimp fishermen in his state, where the industry earned $206 million last year and provided one-third of the nation's shrimp catch.

The House Appropriations Committee member inserted language in the supplemental bill that would delay the government regulation for a year, and would call for a study of the effectiveness and cost of TEDs.

''Louisiana is the most depressed state in the nation right now, with the trouble in the oil patch,'' Livingston said. ''For them to say this is the year we want to impose the devices on shrimpers, who have no other gainful employment, is not convincing to me.

''We're not trying to hurt the turtles,'' he said. ''The turtles have survived through the milleniums, and I think they can survive another year while we perform tests'' on the impact of TEDs.

But Ms. Donnelly said the study Livingston has proposed is ''another delaying tactic. The fact is shrimp trawlers kill turtles.''

Shrimp boats drag as many as four nets just above the ocean bottom. The conical-shaped nets typically are about 40 feet wide and 15 feet high at their mouths.

TEDs, installed in the nets, are metal frames with diagonal slats that force entrapped turtles out a trap door. They also allow larger fish to escape while the shrimp remain trapped.

Livingston and the country's shrimpers - who earned $663 million last year, more than any other segment of the nation's fishing industry - argue that the devices allow 20 percent to 40 percent of the shrimp to escape as well. And they say the added weight of the TEDs forces the nets along the ocean bottom, where they become caught on debris.

Supporters, however, say the newest TED models are light at only 37 pounds, do not cause nets to hit bottom and do not diminish the shrimp catch.

''A guy who knows how to rig his net and pull it properly, he isn't going to lose any shrimp, either with a TED or not,'' says Charles Karnella, acting chief of the fishery service's Protected Species Management Division.

The government estimates that 48,000 sea turtles are caught in shrimpers' nets each year. Those that die drown because the creatures breathe air.

Ms. Anderson, the shrimper, said turtle deaths also are caused by pollution, dredging and offshore oil drilling. Shrimpers would be willing to pay to help replenish the turtle population if others would pay as well, she said.