In our last post, you heard
us mention that one of the reasons we do OA surveys is to find out when and
where OA events happen, and how they might impact biology. The link between the
chemistry and the ecosystem is a big reason why we deploy the Bongo nets. On
this project, one of the organisms we are most interested in during this
mission are larval crabs.
 |
| Some of the larval crabs we have collected during this mission. Photo by Jennifer Questel (UAF). |
When I asked Jennifer
Questel, one of our ecologists on board how old these crabs were, she told me just
a couple of weeks! These larval stages are the most vulnerable for red king
crab, the face of the Bristol Bay crab fishery (and one of the types of crab
they pull in during Deadliest Catch). Scientists
at NOAA’s Alaska Fisheries Science Center here in Kodiak, Alaska have shown
that larval king crab have less than half the survival rate of normal crabs
when exposed to ocean acidification levels expected during the next century.
This means that fewer crabs would surviving to adulthood, which could shrink
the overall adult population.
Lower crab populations
likely mean lower crab harvests, and this could be a big challenge for Alaska given
that so much of the state’s fishing revenue comes from crabbing. Annually, the
crab fishery pulls in around $200 million USD.
Jennifer and Caitlin have
been setting aside larval crabs they find in the bongo nets for Dr. Robert Foy
of the Alaska Fisheries Science Center, and the informally named ‘Crab Lab.’
These specimens will be carefully examined for any potential physiological
impacts of ocean acidification. We’ll also take a look at the spatial
distribution of these baby crabs to see if there are any corresponding patterns
in ocean chemistry and the presence of these organisms.
It’s important to remember
that we still have a long way to go towards understanding the complete impacts
of ocean acidification on crab fisheries around Alaska, but there is a lot of
current research being done. Dr. Foy’s team is working on laboratory studies
that show how acidification impacts king and tanner crabs. This data is then
built into models that predict just how much acidification it will take to
impact future crab populations. OARC is also working to understand how
acidification will play into the overall Alaskan economy.
Want to know more? Check out
these links:
--Jess
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