Warmer climate could result in undersized fish

Climate changes affecting the oceans could stunt the growth of fish, according to researchers at the University of British Columbia. With computer modeling, fisheries scientists studied more than 600 species of fish from oceans around the world. One of the results shows that the maximum body weight could drop by 14 to 20 per cent from the years 2000 to 2050.

"Marine fish are generally known to respond to climate change through changing distribution and seasonality. But the unexpectedly big effect that climate change could have on body size suggests that we may be missing a big piece of the puzzle of understanding climate change effects in the ocean,” says lead author William Cheung, an assistant professor at the UBC Fisheries Centre.

The study is the first global-scale application of a 30-year old theory by Daniel Pauly who says that fish growth is limited by oxygen supply. Pauly is a principal investigator with UBC's Sea Around Us Project and co-author of the study.

"It's a constant challenge for fish to get enough oxygen from water to grow, and the situation gets worse as fish get bigger,"explains Pauly. "A warmer and less-oxygenated ocean, as predicted under climate change, would make it more difficult for bigger fish to get enough oxygen, which means they will stop growing sooner.”

This study emphasizes something that we already know: to cut down greenhouse gas emissions and to monitor and adapt to changes. Otherwise we put ourselves in danger by dusrupting fisheries, food security and the way ocean ecosystems work. The study is published in the journal Nature Climate Change.