Mystery invertebrate in a red crab

Observation by Kendra Lee:

Unsure what type of bug was found in Alaska red crab, located in the lung/gills. An Alaska King crab, they aren't as big in Nome as the southeast Alaska King crab. The crab was brought in by a catcher seller in Nome.

Comment by Gay Sheffield of UAF Sea Grant:

This is an amphipod (Ampelisca sp.). They are often found clinging in bunches to your crab bait if you are hand crabbing through the ice using a line and a weight with fish bait. These amphipods are also what the auklets, ringed seals, and gray whales, etc. like to feast on at times. Happily, they are common in the region, provide food for many marine organisms, and help quickly recycle dead flesh back into the marine ecosystem.

Comment by Asia Beder of ADF&G:

That would be a sand flea. Not sure exact species but they are common. Usually found in muddy bottoms and seem to be attracted to bait and shellfish/fish trapped in fishing gear. They will eat crab and fish, so fishermen often have to limit the soak time of their gear in areas where sand fleas are in abundance.

LEO Says:

Talitridae is a family of amphipods. Terrestrial species are often referred to as landhoppers and beach dwellers are called sandhoppers or sand fleas. The name sand flea is misleading, though, because these talitrid amphipods are not siphonapterans (true fleas), do not bite people, and are not limited to sandy beaches. In the side bar please refer to the link on Talitridae for further information.