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Dive Dry with Dr. Bill

#371: The Rubberlip Seaperch

A group of fish species found in our waters is the surfperch family, Embiotocidae. This family is mostly found along the Pacific coast of North America although a few species live in the waters off Japan. Some members found in Catalina Island's Casino Point Dive Park are the kelp surfperch, walleye surfperch, pile surfperch and black perch. Today I will describe the largest of the surfperch, the rubberlip seaperch (Rhacochilus toxotes). It is also commonly known as the rubberlip surfperch, bigmouth, porgee, sprat, liverlip and buttermouth. I would assume based on this, it suffers from a severe identity crisis, but these are the names we humans give to them. The rubberlips refer to themselves as Harry, Mary, Bill and Jill.

Rubberlips are distinguished from other surfperch by their large size. They are the biggest members of the family, reaching 18 1/2 inches in length. Their large, fat, white to pink lips are also a distinctive feature. In keeping with the playoff season, their bodies are sometimes referred to as "football shaped." I'm not sure my great uncle George Halas, former owner of the Chicago Bears and co-founder of the NFL, would see eye-to-eye with his great nephew on this! Body color is variable, ranging from dark to pale silvery gray to silvery olive or brassy.

This surfperch is found from Russian Gulch State Beach in northern California to Thurloe Head in central Baja California, Mexico. They frequent areas with structure such as kelp beds, rocky reefs, pier pilings and offshore oil rigs. Occasionally they may be found in shallow backwater areas, but they generally avoid surf-exposed beaches. Although these surfperch have been seen down to depths of over 150 feet, they are most commonly found in 10 to 100 feet. Rubberlips are considered demersal, or bottom dwelling, and they are frequently found just above the substrate. They may also be seen in midwater, usually just below the canopy of the kelp forest.

While researching this species, I was surprised to find that it was first scientifically described in 1854 by the great biologist Louis Agassiz. Agassiz became a professor at my alma mater, Harvard, in 1848 so his work on this Pacific coast species occurred during his tenure there, and he published a monograph on the unusual surfperch species he examined from California. Agassiz is known for his work to seek funding for the University's Museum of Comparative Zoology, completed in 1860. I did much of my early marine biological research in that building as an undergraduate. Agassiz also urged the formation of a National Academy of Sciences and became a founding member in 1863. Despite his great accomplishments, Agassiz was a lifelong opponent of Darwin and his theory of evolution.

Adult rubberlip feed on bottom dwelling invertebrates like crabs, shrimp, amphipods and octopus; while the juveniles prefer worms, tiny snails, mussels and small crustaceans. They generally feed on them by cruising above the algal turf on the bottom. Because several other surfperch species utilize similar feeding patterns, they are referred to as a feeding guild. This is similar in concept to guilds formed by workers who practice a common trade such as plumbing or carpentry.

Some surfperch including rubberlips utilize a strategy known as "winnowing" to extract food from the bottom. They will ingest a mouthful of the material, then separate out the useful food components and spit out the non-living material and inedibles such as algae. Of course this makes them rather sloppy eaters, and eschewing vegetable components in the diet makes them carnivores. Heck, even I'll eat vegetables on occasion... as long as they aren't asparagus, lima beans or peas.

The surfperch are one of the few fish families that birth their young live. During courtship, the males may turn dark in color and perform a "dance" to attract the attention of the ladies. They swim slowly over the bottom with their heads pointing down. I have no idea why this might attract the girls, and don't intend to try it myself some night at the Chi Chi Club. However, it seems to work for them as a single male may tend several females. A three pound female nearly 17" in length was found to have 21 young inside averaging a little over 3 1/2 inches in length. That sure puts "octomom" to shame! An adult fish this size may be "only" nine years old.

Of course the rubberlip and other surfperch are not top level carnivores like me and great white sharks. They are fed upon by harbor seals and Brandt's cormorants. As the largest of the family, they are taken in relatively modest numbers by recreational anglers using bait such as mussels, clams, sand worms and cut shrimp. In the Monterey area they are the most significant species in the commercial surfperch fishery. At least this is one fish family that can legitimately be marketed as "perch" unlike the grunts and sea chubs covered previously!

© 2009 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Rubberlip showing large lips, and feeding as a rock wrasse waits for the scraps;
darker male courting a female, and a pregnant female.

This document maintained by Dr. Bill Bushing.
Material and images © 2010 Star Thrower Educational Multimedia