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These spider crabs, Macroregonia macrochira, were collected from a depth of 2,900 m on Pratt Seamount.

After I remove the crabs from our traps, I take them into the lab so that we can take our samples.

Crabs have an open circulatory system, which means that their blood passes through cavities, called sinuses. The sinuses are low pressure compared to the vessels in our own closed circulatory systems.

After we take a 3-ml blood sample, we look for any Craprellid amphipods, which are commensal organisms, that live inside the crab's mouthparts.

After looking for the amphipods, we take several measurements, including carapace (shell) length and width.

We also take a gill sample for genetic analysis to see how closely related these crabs are to other species, such as tanner and snow crabs.


Related Links

Gulf of Alaska 2004

Gulf of Alaska 2004: August 20 Log

NOAA Ocean Explorer Gallery