Rising Ocean Temperatures Are Stressing Fish Out

morwong photo
Photo: Joi / cc

Fish have a lot to worry about these days, what with oil spills, Texas-sized islands of floating plastic debris, and overfishing -- but, according to the latest research, rising ocean temperatures are causing them quite a bit of stress as well. Biologists studying a particularly long-living fish in the Tasman Sea have discovered that, as waters continue to warm as a result of climate change, their usual growth cycles are pushed to the limit -- and the fish aren't the only ones who need to worry about it.Environmental data from the Tasman Sea dates back to the early 1940s, and since then researchers have measured an increase of 2 degrees Celsius for surface temperatures -- said to be among the most dramatic increases out of any place in the world. As oceans get warmer, say biologists, cold-blooded fish can generally cope with the change by increasing in size, but that only goes so far.

Morwong, a species of fish native to the region, were the focus of a recent study to determine the effect of rising temperatures. The fish can live to be around 100 years old, and typically do not migrate far beyond their breeding grounds -- making them the ideal fish for the research off the coast of Tasmania.

"By examining growth across a range that species inhabit, we found evidence of both slowing growth and increased physiological stress as higher temperatures impose a higher metabolic cost on fish at the warm edge of the range," co-author of the study, marine ecologist Ron Thresher, told Reuters.

The results of this study could have broad implications on the future success of commercial fishermen, particularly as the emission of greenhouse gases continue to lead to higher ocean surface temperatures throughout the globe. "A lot of commercial fish don't move very much," says Thresher.

The news comes on the heels of reports regarding the perilous state of the ocean's fish stocks, from environmental issues and overfishing. If current trends continue, the availability of a once-reliable source of food will be jeopardized, spelling disaster for a host of communities that rely on the fishing industry.

More on Rising Ocean Temperatures
Past Decade the Hottest on Record
Indian Ocean Shows Signs of Global Warming

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