Sticklebacks and Climate Change: Will "Darwin's Fishes" be Winners? 08/25/2010 | Marilyn Sigman, Alaska SeaGrant/MAP Tags: Climate Change, Climate Change Impacts on Alaska Marine Ecosystems, Resiliency to Climate Change, Sticklebacks

A recent study provided additional evidence that sticklebacks have one of the fastest evolutionary responses in wild populations, which could make them particularly resilient to changes in water temperature. University of British Columbia researcher Rowan Barrett and colleagues in Switzerland and Sweden reported on the results of experiments demonstrated that, in little as three years, freshwater sticklebacks developed tolerance for water temperatures 2.5 degrees Celsius lower than their ancestors.

Stickleback fish are believe to have originated in the ocean and to have begun populating freshwater lakes and streams following the last ice age. Over the past 10,000 years, marine and freshwater sticklebacks have evolved different physical and behavioral traits. They are considered ideal models for Darwin's natural selection theory. Sticklebacks have even been dubbed "Darwin's Fishes," a "star" and"superstar" of evolutionary research, and, according to Nature magazine, one of "15 Evolutionary Gems." The entire genome has been sequenced from a type specimen from Bear Paw Lake, Alaska, a lake currently under threat of invasion by northern pike.

They were first studied extensively for their mating behaviors and made famous by Tinbergen. More recently, they have been the focus of studies of their abilities to adapt quickly to fresh water after being isolated from salt water. Studies have done on the three-spine stickleback throughout its northern range including artificial ponds on the U.B.C. campus in Vancouver, in Lake Washington in Seattle, and in Alaskan fresh water lakes that were a result of relatively abrupt geologic changes like uplift following the 1964 Earthquake in Southcentral Alaska and lake formation following glacial retreat.(more about Alaska studies). The body of the fish shifts from one with heavy armor plates to unarmored and shorter and fewer spines. Their skin color becomes lighter, probably for camouflage. These shift happen quickly from the standpoint of evolutionary time.The change in body armor appears to be under the control of a single gene.

"Our study is the first to experimentally show that certain species in the wild could adapt to climate change very rapidly - in this case, colder water temperatures. However, this rapid adaptation is not achieved without a cost," says Barrett. "Only rare individuals that possess the ability to tolerate rapid changes in temperature survive, and the number of survivors may not be large enough to sustain the population. It is crucial that knowledge of evolutionary processes is incorporated into conservation and management policy."

For a lighter look at climate change and the abilities of species like walrus to adapt, see the video recently produced by the Monterey Bay Aquarium.

Sources:
Tiny fish evolved to tolerate colder temperatures in 3 years: UBC study. Brian Lin UBC 8/4/10 press release to AAAS EurekaAlerts.
Darwin's fishes: the threespine stickleback of the Pacific Northwest. Sandi Doughton, Seattle Times, 2/15/09
Stickleback genomes shining bright light on evolution . ScienceDaily, 3/8/10