Tuna Crabs Hit San Diego

For the past several weeks, the crustaceans often referred to as tuna crabs (Pleuroncodes planipes) have been washing ashore onto San Diego beaches and observed in the waters just offshore.

Normally pelagic and found to the south of us, typically their appearance hereabouts is considered associated with El Nino conditions. As far as I can tell, the last major "invasion" was in 2002, which was considered a moderate El Nino year.

I paid a trip to the San Diego River mouth, and then Mariner's Basin in the southern portion of Mission Bay, and the tuna crabs were spread pretty continuously along the edge of the shore in both places - not in massive numbers, but certainly widely present. I have heard that they have showed up in Coronado, Pacific beach, and likely in other places also.

Surprisingly, the gulls and other water birds did not seem to be partaking of them very much (I only saw one gull take off with one).

Most of the specimens I saw were alive, but unhappy, to say the least, about being pushed ashore onto the sand. They were very photogenic though!

One of the first I saw at the San Diego River mouth. Since this spot is close to Dog Beach, the dogs were a big part of the landscape and for some reason liked coming over and barking at top volume, and close range, while I knelt down to photograph the little red guys.

Some were assembled in little groups in the shallows right along the river edge.

This one was in a little tidal pool, very shallow, so easy to get a photo of "in its element".

A stranded one, sitting on kelp on the sand.

Another angle of the kelp-sitter.

Those in the shallow water formed some interesting, orderly patterns. Trying to maintain personal space?

This little one really looks endearing. Sad that they will all certainly be dead soon.