THE program to recover endangered fish in the upper Colorado River Basin - the Colorado squawfish, the humpback chub, the bonytail chub, and the razorback sucker - will take at least 15 years.That may seem like a long time, but it's a blink of an eye compared with how long they've been around. The youngsters in this group - the humpback and the bonytail - evolved about 10,000 years ago. The other two go back more than three million years. As with most species facing extinction before their time is naturally up, the problems are linked to man: dams, reservoirs, and other water development projects, plus the introduction of non-native sport fish that prey on native eggs and fry. The recovery program, which became official three years ago, is designed to help the fish recover to the point where they are "self-sustaining" while allowing water development to continue. It includes input from state and federal resource agencies, water users' groups, the National Audubon Society, and the Environmental Defense Fund. It's expected to cost $60 million, with about $10 million of that coming from special water-development fees. Among the recovery program elements: improving and creating habitat, building fish passageways around dams and other diversions, raising hatchery fish from "brood stocks," learning how to artifically imprint hatchery fish to natural spawning areas, controlling where sport fish are stocked, and evaluating the genetic differences between fish populations from different river systems and between wild and hatchery fish. Locating existing fish is a tough job. The upper Colorado River Basin includes 10 major rivers and more than 1,000 miles of white water in steep canyons. But last August, biologists found 13 razorback suckers in a pool, the largest concentration found in the mainstem upper Colorado in 20 years. They were taken to a New Mexico hatchery to establish a brood stock.