With rising Carbon dioxide levels many Scientist are worried about the unpredictable future of Alaska’s King crab fishery.The loss of King crab could have major impact on Human consumption/ and how much King crab is harvested in commercial fishing which effects our economy ( money and jobs).
One major concern about high CO2 levels is when Carbonic acid releases a H+ ion it joins with a carbonate ion leaving calcium alone with no way to form Calcium carbonate. Corrosive waters have a much lower concentration of calcium carbonate making it hard for organisms such as crabs that need the calcium carbonate for exoskeleton growth.
A study done by Robert Froy and colleagues experimented with Red king crab that was harvested in 2009 from Bristol Bay, Alaska. In this study Brooding females were placed in two environments (controlled: pH 8.0; acidified environment: pH 7.7) to get a better understanding of the effect of ocean acidification on embryo development and larvae release. They placed larvae in both the control and test environment to determine whether ocean acidification would have effects on larvae survival and they also looked at effects over different life stages. In this study the CO2 was used to acidify waters in several tanks: the figure below shows the setup system that was used to supply acidified and control seawater to experimental tank. Crabs in this study were selected randomly and placed in either the control tank or acidic tank.
The study showed that a slight change to the pH in water can have effects on embryogenesis, larvae development / survival, and molting of the adult females. For future studies the researcher wants to look at pH and temperature how this could potentially lower Red king crab tolerance.
So what does this mean for future crab populations?
In the 1970’s and 1980’s crab population crashed near Kodiak Island. For years a shellfish hatchery has been experimenting with learning how to raise baby king crab from scratch, in order to release these crabs in areas where their species have been exhausted. Scientists believe this might be a way to remedy the future loss of king crab if the threats of ocean acidification persist.
Long WC, Swiney KM, Harris C, Page HN, Foy RJ (2013) Effects of Ocean Acidification on Juvenile Red King Crab (Paralithodes camtschaticus) and Tanner Crab (Chionoecetes bairdi) Growth, Condition, Calcification, and Survival. PLoS ONE 8(4): e60959. doi:10.1371/journal.pone.0060959
Article Citation: W. Christopher Long, Katherine M. Swiney, and Robert J. Foy . Effects of ocean acidification on the embryos and larvae of red king crab, Paralithodes camtschaticus. Marine Pollution Bulletin, Volume 69, Issues 1—2, 15 April 2013, Pages 38—47.
Video link: Lucrative crab industry in danger