Adding to the concern over industrial commercial overfishing, researchers from the University of British Columbia have stated that changes in ocean and climate systems could lead to smaller fish. Their research, which was published in the journal Nature Climate Change, is the first-ever global projection of the potential reduction in the maximum size of fish in a warmer and less-oxygenated ocean.
Using computer modeling to study more than 600 species of fish from oceans around the world, the researchers found that the maximum body weight of fish could potentially decline by 14-20% between years 2000 and 2050, with the tropics being one of the most impacted regions.
“We were surprised to see such a large decrease in fish size,” said the study’s lead author William Cheung, an assistant professor at the UBC Fisheries Centre. “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.”
The idea that fish growth could be affected by limited oxygen supply was first theorized 30 years ago by Daniel Pauly, principal investigator with UBC’s Sea Around Us Project and the study’s co-author.
“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.”
Via BBC News