Aug. 12 (Bloomberg) -- Humpback whales are no longer threatened with extinction, while the risk has increased for some dolphins and porpoises, the International Union for Conservation of Nature said.

The latest Red List of endangered species will classify the humpback, protected from hunting since the 1960s, as ``least concern,'' the conservation group said today in an e-mailed statement. The whale's previous rating was ``vulnerable,'' one of three categories reserved for species that face extinction in the wild. Commercial hunting of all whales was banned in 1986, the group said.

``This is good news: humpbacks have been recovering through most of their range,'' Randall Reeves, the Hudson, Quebec-based chairman of the union's specialist group on whales and dolphins, said yesterday in a telephone interview. ``Protecting animals works as a simple but very effective strategy.''

Even as larger whale species recover, coastal and river- living dolphins face threats from fishermen and ships, according to the conservation union. The Yangtze River dolphin, or baiji, was listed as ``possibly extinct'' last year, and the vaquita, a porpoise that lives in Mexico's Gulf of California, may follow, the group said.

``River dolphins are one of the most threatened cetacean categories, mainly because they are locked in competition with humans for dwindling freshwater resources,'' Jean-Christophe Vie, deputy head of the union's species program, said in the statement.

Mexican Porpoise

The vaquita is listed as ``critically endangered,'' the highest degree of threat. The population is about 150, and 15 percent are killed annually by fishing nets, the union said.

Entanglement with fishing gear, and strikes by ships are the biggest threats to large whales, Reeves said. Coastal porpoises, dolphins and smaller whales are threatened by a type of fishing gear known as gillnets, making them harder to conserve, he said.

``Even if one protects them from deliberate harm, there are a number of things that people are engaged in that just aren't compatible with the safety of these animals,'' Reeves said. ``It's one thing to be able to manage deliberate hunting or killing, but when it's accidental and happens in the process of humans going about their normal business of commerce and feeding themselves, then it becomes a really tough thing to solve.''

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net.

Last Updated: August 11, 2008 20:00 EDT