Study findings show a possible bright spot for a commercially important population hammered by a warmth-triggered crash
Bering Sea snow crab, with two specimens seen in this undated photo, support an iconic Alaska seafood harvest, but a crash in population since 2018 triggered the first ever closure of the fishery in 2022. That closure was extended for the 2023-24 season. A newly published study shows that snow crab have some resilience to ocean acidification, with eggs and embryos that fare better in acidified conditions than do those of other Alaska crab species. (Photo provided by National Oceanic and Atmospheric Administration)
The beleaguered snow crab of the Bering Sea may have one strength that could help their population endure rapidly changing marine conditions: an apparent resilience to ocean acidification.
Research by National Oceanic and Atmospheric Administration scientists in Kodiak has found that juvenile snow crabs are not harmed when reared in more acidic waters. That is a contrast with other types of crab found in Alaska waters and even with bairdi crab, commonly referred to as tanner crab, which are closely related to snow crab.
The results come from an experiment that held females for two years and observed development of embryos and larvae from eggs hatched in each of the years.
“The embryos did just fine. They hatched out just fine both years. We didn’t see any indications of negative effects on embryo development,” said Chris Long, the study’s leader and a scientist at NOAA’s Alaska Fisheries Science Center laboratory in Kodiak.
The study found some minor effects on larvae in the first year but not in the second year, he said.
The experiment’s structure duplicated the structure for an earlier tanner crab project, Long said. That project found that negative effects from acidification in tanner crab emerged in the second year, and they were profound, with 70 percent of the eggs failing to hatch, he said.
The new findings also parallel those from other research that found that snow crab shells are more resilient to acidified waters than are tanner crab shells. In that experiment, Long said, snow crab shells remained intact after two years’ exposure to acidified waters while tanner crab shells deteriorated.
Resilience to ocean acidification could be important for snow crab and other Bering Sea species. The Bering Sea is, by its nature, conducive to acidification because of its cold waters, high carbon content, wide seasonal swings and a particular combination of ocean mixing characteristics. Previous research has found that the world’s most acidic ocean waters are found in the northern Bering Sea during the winter, when sunlight is scarce and carbon-absorbing plankton cannot bloom. And Bering Sea acidification is expected to increase into the future as the oceans continue to absorb the carbon being pumped into the atmosphere.
The findings about snow crab embryos and larvae provide a bit of good news in an otherwise bleak picture for the species in Alaska that has supported a lucrative fishery in the past.
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Alaska Beacon, Yereth Rosen, 11 November 2023. Full article.
