UT researchers: Transplanted fish can thrive, offer hope for restoration

Think, for a moment, about a guy in a bar who doesn’t speak a word of the language or know any of the local customs but tries to pick up women anyway. He probably won’t have much success. Evolutionary research suggests the picture is similar when any animal from one area — say, a fish in a stream — ends up among a group of its species in a different area, such as a school of lake fish.

But new University of Texas research into fish suggests this metaphor might not be the case. An animal that finds itself in a new group might actually be more like the guy at the bar with a suave Brit- ish accent — more likely than the locals, perhaps, to thrive socially and pass along genes to the next generation.

“Such immigrants are usually rare (in nature), and we have found that sometimes their rarity provides a competitive edge,” said Daniel Bolnick, a UT researcher who studied a species of Canadian freshwater fish. “We found newcomers in the population pass on their genes more often than residents, and they contribute more to the next generation.”

The research, published last week in the academic journal Nature, doesn’t turn established thinking on its ear. The study did, after all, only look at one species of fish. But it does suggest that in some situations, such as the restoration of endangered species, bringing animals from one population into another could be a more successful strategy than is generally believed.

Bolnick and his co-author, former UT graduate student William Stutz, studied the threespined stickleback, a species that lives in Vancouver, British Columbia. They observed two populations, one of which lives in a lake, another in a nearby stream.

The most obvious difference: The stream fish are far larger. But the lake fish, being adapted to that environment, should fare better there than their cousins from the