Washington — When researchers stumbled across the Amistad gambusia in the late 1960s, the small fish's days were already numbered. Its only natural habitat was inundated by a dam-building project soon after the discovery, and the few survivors slowly died out.
Earlier this month the US Fish and Wildlife Service made it official: the Amistad gambusia is extinct - the latest addition to a list of creatures that have vanished forever from the United States. If not for the timing, the fish's fate might have been different. The Endangered Species Act of 1973, now up for renewal in Congress, probably could have saved the Amistad gambusia's single Texas spring if it had been on the books at the time.
Since its passage, the law has forced the rerouting of highways, the scuttling of water projects, and even restrictions on urban sprawl - all in the name of wildlife preservation.
But why worry about a little fish? After all, it's not as though anything ground to a halt when the species was lost.
``The act isn't designed for one little critter; it establishes the importance of the `web of life,''' says Ron Lambertson, head of the Fish and Wildlife Service's endangered species program. ``When you look at the whole web, you realize that no single species is unimportant.''
Scientists emphasize the need for biological diversity. Plants and animals, no matter how obscure, provide genetic resources essential to agricultural and medical technology, they say, and these can have major economic value.
The Endangered Species Act spells out actions the government has to take to protect and restore dwindling species, including the development of recovery plans. The program has scored some big successes, including the resurgence of the brown pelican and bald eagle. Other major efforts are aimed at saving the California condor, black-footed ferret, and red wolf.
But the bulk of the 480 threatened or endangered species indigenous to the US have been lucky just to hold their own. At least 10 listed species have gone extinct since 1973, including the Wyoming toad, the dusky seaside sparrow, and the Palos Verdes blue butterfly. The Fish and Wildlife Service must formally delist a species and has so far done this only for six. Many more are thought to have been extinct when put on the list; others disappeared before they could be listed.
The extinction rate is much higher in other parts of the world than in the US. It is estimated that, worldwide, 1,000 plants and animals become extinct every year.
``If you measure the success of the act in terms of the number of species that have been completely recovered, then it's very small,'' says Michael Bean, chairman of the Environmental Defense Fund's wildlife program. More important, he says, has been the law's ability to slow the overall trend toward extinction.
John Fitzgerald of the Defenders of Wildlife says, ``We would have lost a lot more of these species if it wasn't for the act.'' But despite its relative success, the Endangered Species Act has grown increasingly controversial. The law technically expired in 1985, and early efforts to reauthorize it were held up by a group of Western senators over the issue of hunting endangered species. The Reagan administration complains that Congress tampers with the act too much. In reauthorizing the law in 1982, for instance, the lawmakers extended protection to threatened or endangered plants found on federal lands.
The Reagan administration has routinely asked for less money than Congress has approved for the program, but even that is far less than is needed to actually implement the whole range of initiatives. Fish and Wildlife has developed almost 250 recovery plans, but only has the funds to implement a small percentage of them.
Meanwhile, there is a backlog of some 4,000 species that are active candidates for listing as threatened or endangered. Almost a quarter of these are ``category 1'' candidates - meaning that the government has all the information it needs to make a decision but simply hasn't grappled with all the paper work.
Even at the current, relatively brisk rate of 50 listings a year, it will take the Fish and Wildlife Service more than 70 years just to sift through the candidates.
A version of the act approved by the House two weeks ago would authorize spending $56 million on the program next year, with the budget growing to $66 million by 1992. That's a sizable increase over the $39 million spent this year.
The House bill, similar to a package approved by the Senate Environment and Public Works Committee earlier this fall, includes several provisions lobbied for by environmentalists. It increases penalties for violators of the act, extends protection for plants, and directs the secretary of the interior to monitor the status of candidate species.
Environmentalists hope that the firm support for the bill in the House will send a signal to the Senate. But they worry that efforts to attach special amendments to the act could scuttle the process once again.
During the recent House deliberations, some congressmen showed their dissatisfaction with the act by offering amendments. One sought to delay the use of special shrimp nets that protect turtles from drowning. Such attempts to weaken the act underscore the difficulty faced by the endangered-species program.
Actions taken to protect a single species are often portrayed by critics as extreme. Who could forget the snail darter? That three-inch fish forced the Tennessee Valley Authority to stop work on the Tellico Dam.
Even many environmentalists admit that some balancing of priorities will ultimately be necessary. In Palm Springs, Calif., for instance, local authorities have developed a program that reconciles future growth with a rare species of lizard. Under the plan, land developers will set aside three separate preserves as they expand out into the animal's habitat.
Meanwhile, the Endangered Species Act has guaranteed the kind of close scrutiny that is likely to make it more difficult for things to happen the way they did for the Amistad gambusia. ``The act has given us the means to rescue most of the species on the list now,'' Mr. Bean of the Environmental Defense Fund says. ``The main constraint is still resources.''
Endangered species score card
Number of species in the United States or its territories on the threatened or endangered list: 990 (480 native to the US).
Extinct, removed from the list: 6.
Found to be more plentiful than originally thought or removed from the list for other reasons: 4.
Fully recovered: 3, all birds native to the Palau Islands in the western Pacific.
Covered by recovery plans: 247.
Candidates for the list: 962. The government has enough information on hand to list these species, it's just a matter of sorting through the paper work.*
Possible candidates: 2,951. There is enough information on these to suggest that listing may be appropriate, but conclusive data on biological vulnerability are not yet available.*
No longer being considered: 1,633. These species were nominated in the past, but never made it past the candidate stage. They have either gone extinct, failed to meet the definition under the act for a separate species, or been found to be more plentiful than originally thought.*
(* Figures as of 1985, the last year for which complete information on candidates is available.)