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.

Avian Feeding Frenzy with Anchovies on the Menu

Just south of the southern end of Imperial Beach, the feasting continued today. I arrived around 1:30 pm or so, and watched the masses of terns, gulls, pelicans and shearwaters circling and diving, with many floating on the water.

By about 2:30 most of this mass had dispersed.

One anchovy washed ashore - surprising that so few seemed to make it to the sand, considering the chaos just off the beach.

The mass of birds at a slight distance.

This was about the peak of activity that I observed. Coronado Islands in the background.

At this point many of the birds were just a couple dozen feet out from the sand, with some right at the shore's edge. There were a few fish in the shallows in this spot.

The cause of all the fuss (or more accurately, this one's buddies offshore!).

There were small feathers all over the wet sand.

Looking towards the north, the line of terns and other birds went on well into the distance. 

Sea Star Wasting Syndrome in Oregon (and Elsewhere)

We made a trip to Oregon in mid-June, and visited several beaches and tide pool areas from northern California up to Otter Rock, Oregon (which is just north of Newport).

Last September, we visited Otter Rock and spent about an hour wandering around at the fantastic tide pools just below the inn. The Ochre Sea Stars (Pisaster ochraceus) were in good numbers and seemed healthy and happy (as a sea star can seem).

Ochre Sea Stars at water's edge, September 2013, Otter Rock, Oregon

Otter Rock, September 2013

Otter Rock, September 2013

This June, we saw no truly healthy looking Ochre Sea Stars, although we did see a fair number of individuals of this species. They all looked withdrawn at the least, or "half-melted" in more dramatic cases.

Otter Rock, June 2014

Otter Rock, June 2014

A biologist at the Hatfield Marine Science Center confirmed that the disease has been detected in the area very recently.

In contrast, the rest of the tide pool ecosystem seemed healthy to our fairly untrained eyes.

Purple Sea Urchins were very abundant and filled the bottoms of some tide pools. Otter Rock, June 2014

Leopard Nudibranch, Diaulula sandiegensis, Otter Rock, June 2014

Ochre Sea Stars are often used as an example of a keystone species in ecology lessons, as they eat mussels, thus reducing the coverage of the rocks by these bivalves, and allowing a greater diversity of species to live in a given area. Without Ochre Sea Stars, mussels tend to become so abundant that they take up vast areas of prime intertidal "real estate", forcing other species out of the area.

We saw what appeared to be new crops of baby mussels at Otter Rock - likely a trend to follow the demise of the sea stars.

Small California Mussels, with Gary's feet for scale.

Happily, at Humbug Mountain State Park, further south on the Oregon coast, we saw very healthy (and hungry) Ochre Sea Stars. I had never seen so much mussel-eating before!

A hefty California Mussel just visible underneath this healthy Ochre Sea Star. Humbug Mountain SP, Oregon. June 2014.

Another sea star looking suspiciously like it's dining on mussel. Humbug Mountain SP, Oregon. June 2014.

Now the sea star wasting syndrome has hit our San Diego coastal area, so it may experience dramatic changes in the months and years to come, also:

http://www.utsandiego.com/news/2014/Jun/20/environment-sea-star-wasting-syndrome-san-diego/

When I first moved to San Diego County with my family in 1977, and for years after, I never found sea stars of any kind at the tide pools in La Jolla and elsewhere locally, and only in the '90s and 2000s did I see good numbers of sea stars here in the San Diego region. Perhaps the trend will be a reversal to what I saw in the seventies, at least for a while.