Have a Crabby Day!

Tuesday, May 15, second entry –  The Biological Oceanography students at Florida Tech go crabbing!

We used “crab rings” and hurled them off the boathouse dock at the Oregon Institute of Marine Biology. The rings are tied off with a long rope and have bait, in our case raw chicken, hooked to the center.

Lauren hauls in Dungeness and Red Rock crabs
The crabs say, “chicken is GOOD!”

When the rings are hauled in, the crabs feeding on chicken can’t jump out against the push of water rushing past.  The dock was is near the mouth of the bay, so outer coast crabs may come into the inlet on an incoming tide.  Biological Oceanography students took turns baiting hooks and hurling the rings into the deepest water we could reach.  When examining a haul, we needed to first check their gender (females go free according to state law),

It happens that the legal size for crab carapace width is about the same as US paper currency length, so…

and then males are checked for legal size (a quarter inch shy of the length of a dollar bill in carapace width).  While we were down at the boathouse dock, the Florida Tech Biological Oceanography students saw a baby harbor seal, which appeared to be still of a nursing age. Kai was ready to jump in with it, but it never resurfaced after the initial sighting.

Liza and Hannah prepare the new CTD for deployment off the boathouse dock.
Hannah lowers the CTD into the water to record the salinity and temperature profiles.

We also initiated the maiden deployment of our new compactd “CastAway” CTD to determine the temperature and salinity profiles of the water column near the mouth of Coos Bay.  This can reveal what sort of water the crabs prefer, and also elucidate the nature of this coastal Oregon estuary.

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