Researchers are looking for ways that crab and fish in Alaska may be able to adapt to more acidic ocean water.
With carbon dioxide levels rising on the planet, ocean water absorbs some of that CO2 and water becomes more acidic. That change is already impacting a variety of sea creatures.
Members of the Alaska Ocean Acidification Network gave an update to Alaska’s Board of Fisheries and a public presentation on the topic in Anchorage in October. The network is a group of researchers, managers and stakeholders interested in the looming problem.
“It’s not that there hasn’t been variability in the amount of carbon dioxide. It’s not that this hasn’t happened before,” said Robert Foy, director of NOAA Fisheries Alaska Fisheries Science Center. “It’s the speed at which it is happening during our lifetime and whether or not the animals and plants in the ocean are able to adapt fast enough given the speed at which it’s occurring.”
Foy outlined recent research from a variety of sources on the impacts of the ocean change on crab and fish. Researchers are testing different sea creatures in the acidic water expected over the next 30-50 years. Scientists have seen impacts on shell building, growth, reproduction and survival on some types of shellfish. He said acidic water has shown an impact on survival of king and Tanner crab, but not all of them.
“So what we found with Tanner crab is that it appears those Tanner that did survive in year two survived in year three as well, they acclimated. So it could be their genetic response, the response of those particular individuals allowed them to survive in this environment. So what it means is there’s going to be winners and losers in the long run. And what it also means is that we have an opportunity that if we appropriately manage these species then we may be able to sustain them through these stressors that we’re expecting to see.”
Foy told the Board of Fish that initial results show that the state may see a 50 percent decrease in catch and profits in Tanner crab within the next 20 years. Other studies show a changing ocean will have an impact on behavior, growth and predator avoidance for some salmon species.
Toby Schwoerer with the University of Alaska’s Institute of Social and Economic Research explained that the hope was to manage fisheries for a tipping point, when conditions change dramatically in the Gulf of Alaska. Schwoerer pointed to a change in ocean temperatures in the gulf in the late 1970s.
“You know it’s a mixed bag,” Schwoerer said. “Some species are going to increase, some species are going to slowly decrease, some species are going to rapidly collapse. And I think it’s important to keep those especially harvestable or commercial species, if those are the ones who are going to collapse rapidly, those are the ones we going to keep an eye on.”
Other past research has highlighted that fishing communities in Southwest and Southeast Alaska are at the highest risk from a changing ocean. Here in Southeast that includes Sitka, Wrangell, Petersburg and Prince of Wales Island, places with economies that rely heavily on commercial and subsistence fisheries. The changing ocean chemistry is occurring at the same time that unusually warm sea water temperatures are also playing a part in fish distribution and survival.