I wonder how three similar and closely related surfperch can live together on homogenous sandy beaches. How do they subdivide theoutershores? One solution might be partitioning their food. To study this, I’m learning to identify what they eat; surf perch and their competitors.

IMGP4128_cropped

This is one of the first surfperch food items I ever examined. I think it’s a worm. In December 2011 I wrote a little about this specimen in Prey on the Outer Shores. This specimen remains unidentified, so if somebody can tell me what it is, I would appreciate it.

Smooth Bay Shrimp
Smooth Bay Shrimp
Pacific Mole Crab, Ventral View
Pacific Mole Crab, Ventral View

Much of the surfperch prey is crustacean and I’ve found lots of smooth bay shrimp, Lissocrangon stylirostris and Pacific mole crabs, Emerita analoga, in the stomachs of surfperch.

Idotea
Idotea

Idotea, an isodpod, is a common food item. I should be able to identify this one by the shape of the telson, but so far I’m stumped. I’m hoping somebody will help me out.

Crustacean Eggs?
Crustacean Eggs?

I think these are crustacean eggs, an impressive gob. The Idotea provides scale.

Goose Barnacles
Goose Barnacles

Goose barnacles, Pollicipes polymerus.

Staghorn Sculpin
Staghorn Sculpin
Sand Sole
Sand Sole

Staghorn sculpin, Leptocottus armatus (left), and sand sole, Psettichthys melanostictus (right), both arrive on the beaches in summer, just before surfperch give birth to their babies. Are they predators on baby surf perch or competitors for crustaceans?

Speaking of competitors, here’s one you don’t see every day. An theoutershores reader sent me the following link: http://www.flickr.com/photos/cambriabird/8354888665/in/photostream

This footage was taken on an outgoing tide, mid-morning on January 6, 2013. I’ve never seen anything like this, but apparently some others have, particularly near where this occurred in San Luis Obispo County, California. It looks to me like these birds are dabbling for crustaceans in the surf. What do you think?

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