These spider crabs, Macroregonia macrochira,
were collected from a depth of 2,900 meters on Pratt Seamount.
After I remove the crabs from our traps,
I take them to the lab so we can take our samples.
Crabs have an open circulatory system, which means that their blood
passed through cavities, called sinuses.
They are low pressure compared to the vessels in our own closed
circulatory system.
After we take a three milliliter blood sample, we look for any Craprellid
amphipods, which are commensal organisms, that live inside the crab's mouthparts.
After looking for amphipods, we take several measurements,
including carapace (shell) length and width.
We also open up the carapace
and take a gill sample that will be used for genetic analysis
to see how closely related these crabs are to other species,
such as the tanner and snow crabs.