Rising Sea Temperatures Are Affecting Global Fish Catches: A Study

Ocean warming is having a global impact on what’s for dinner, according to a new study published in the journal Nature.

Previous studies have indicated that some species are shifting location in response to temperature increases, in particular noting the number of fish moving away from the equator in search for cooler waters.

However, the latest report effectively demonstrates that species from warmer waters have also been replacing those traditionally caught in many fisheries worldwide since the 1970s.

In all, the researchers’ results show that, after accounting for the effects of fishing and large-scale oceanographic variability, the global mean temperature change (MTC) increased at a rate of 0.19 degrees Celsius every decade between 1970 and 2006.

Furthermore, non-tropical MTC increased at a rate of 0.23 degrees Celsius every ten years.

These changes, according to the researchers, measured in 52 large marine ecosystems throughout the world’s coastal and shelf areas, “are significantly and positively related to regional changes in sea surface temperatures.”

According to William Cheung, the study’s lead researcher and a professor at the University of British Columbia, these shifts could have several negative effects, especially in the tropics where water temperatures could exceed the preferences of many tropical species, which in turn would result in a large reduction in the number of fish found in the region.

Other impacts, the researchers warn, could include the loss of traditional fisheries, a decrease in profits and jobs and conflicts over new fisheries built to accommodate the distribution shifts. Finally, food security may become an increasing problem, particularly in developing countries, should current trends continue.

“This study shows that ocean warming has already affected global fisheries in the past four decades,” the researchers write in the study, “highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions."