Some halibut may successfully adapt to warmer seas, others may not

Juvenile Greenland halibut. ( Photo by Dongwha Sohn/CEOAS)
Juvenile Greenland halibut. ( Photo by Dongwha Sohn/CEOAS Oregon State)

While their average size is decreasing and 500-pounders are rare today, new research suggests Pacific halibut may adapt favorably to increased ocean temperatures.

Greenland halibut may not be so lucky.

Dr. Cathleen Vestfals, Oregon State University, presented her Ph.D. research at the UAF School of Fisheries and Ocean Sciences Juneau Fisheries Seminar recently.

Vestfals researched the life cycles of two different halibut species that reside in the Eastern Bering Sea: Pacific halibut and Greenland halibut. Both are large flatfish, have big mouths lined with sharp teeth and inhabit some of the same areas.

Pacific halibut get much larger than Greenland halibut do: 8 feet long compared to 4 feet. Pacific halibut are mottled green on top and white on their bottom-facing side. Greenland halibut are blackish purple on top, iridescent yellow-green on their underside.

And they may respond differently to climate change.

Juvenile Pacific halibut (Photo by Morgan Busby/NOAA)
Juvenile Pacific halibut (Photo by Morgan Busby/NOAA)

For her research, Vestfals compared the success of the two flatfish species in past warm and cold years.

Pacific halibut live from California, north through the Bering Sea and across the Pacific to Japan. Due to the extent of their southern range, Pacific halibut may continue to breed and disperse successfully if the ocean becomes a few degrees warmer.

“We would expect that they would do really well under warming conditions. Their habitat is likely going to expand under warming scenarios,” Vestfals said.

Greenland halibut, on the other hand, occupy only circumpolar waters. If the ocean warms by a few degrees, their cold water habitat may contract northward.  According to Vestfals, fisheries scientists already “have noticed a northward shift in species and changes in species assemblages in response to warming.”

So global warming could mean fewer Greenland halibut.

According to Vestfals, Pacific halibut “have a better chance than Greenland halibut would to make it.”

To follow flatfish, visit the Flatfish Fan Club Facebook page Vestfals made.

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