SitNews - Stories in the News - Ketchikan, Alaska

Warmer waters from climate change will leave fish shrinking, gasping for air

 

September 10, 2017
Sunday AM


(SitNews) - Fish are expected to shrink in size by 20 to 30 per cent if ocean temperatures continue to climb due to climate change. And a new study by researchers at the University of British Columbia provides a deeper explanation of why fish are expected to decline in size.

jpg Warmer waters from climate change will leave fish shrinking, gasping for air

Design by Lindsay Lafreniere
Courtesy the University of British Columbia

“Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said William Cheung, co-author of the study, associate professor at the Institute for the Ocean and Fisheries and director of science for the Nippon Foundation-UBC Nereus Program. “There is a point where the gills cannot supply enough oxygen for a larger body, so the fish just stops growing larger.”

Daniel Pauly, the study’s lead author and principal investigator of the Sea Around Us at the Institute for the Ocean and Fisheries, explains that as fish grow into adulthood their demand for oxygen increases because their body mass becomes larger. However, the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body. He calls this set of principles that explains why fish are expected to shrink “gill-oxygen limitation theory.”

For example, as a fish like cod increases its weight by 100 per cent, its gills only grow by 80 per cent or less. When understood in the context of climate change, this biological rule reinforces the prediction that fish will shrink and will be even smaller than thought in previous studies.

Warmer waters increase fish’s need for oxygen but climate change will result in less oxygen in the oceans. This means that gills have less oxygen to supply to a body that already grows faster than them. The researchers say this forces fish to stop growing at a smaller size to be able to fulfill their needs with the little oxygen available to them.

Some species may be more affected by this combination of factors. Tuna, which are fast moving and require more energy and oxygen, may shrink even more when temperatures increase.

Smaller fish will have an impact on fisheries production as well as the interaction between organisms in the ecosystems.

Pauly and Cheung’s study “Sound physiological knowledge and principles in modeling shrinking fishes under climate change” was published in Global Change Biology.

 

Editing by Mary Kauffman, SitNews

 

Source of News:

University of British Columbia
www.ubc.ca

 

 

Representations of fact and opinions in comments posted are solely those of the individual posters and do not represent the opinions of Sitnews.

 



Submit A Letter to SitNews

Contact the Editor

SitNews ©2017
Stories In The News
Ketchikan, Alaska

 Articles & photographs that appear in SitNews may be protected by copyright and may not be reprinted without written permission from and payment of any required fees to the proper sources.

E-mail your news & photos to editor@sitnews.us

Photographers choosing to submit photographs for publication to SitNews are in doing so granting their permission for publication and for archiving. SitNews does not sell photographs. All requests for purchasing a photograph will be emailed to the photographer.