<http://timesofindia.indiatimes.com/home/environment/global-warming/Fi...
ting-smaller-as-oceans-become-warmer-Study/articleshow/16624821.cms> Fish
getting smaller as oceans become warmer: Study

A new study has warned that changes in ocean and climate systems could lead
to smaller fish.

The study led by fisheries scientists at the University of British Columbia
provides the first-ever global projection of the potential reduction in the
maximum size of fish in a warmer and less-oxygenated ocean.

The researchers used computer modeling to study more than 600 species of
fish from oceans around the world and found that the maximum body weight
they can reach could decline by 14-20 per cent 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,"
he noted.

This is the first global-scale application of the idea that fish growth is
limited by oxygen supply, which was pioneered more than 30 years ago by
Daniel Pauly (AFS member, '02), 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," explained 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," he said.

This study highlights the need to curb greenhouse gas emissions and develop
strategies to monitor and adapt to changes that we are already seeing, or we
risk disruption of fisheries, food security and the way ocean ecosystems
work.

The study has been published in the journal Nature Climate Change.

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