Dive Dry with Dr. Bill

#373: Walleye the Bug-Eyed Surfperch

Back in my youth I had a fantastic job. My parents belonged to a sports club (Valley Lo) built around a series of flooded quarries in the Chicago suburbs. We could sail, swim, fish and even dive in the quarries... or play golf on the par three course. I was in charge of the water activities and had a wonderful all-female lifeguard staff, some of whom were even interested in me. No, that wasn't why it was such a great job... after all, I was a clueless teenager and had no idea they fancied me. Now I'm just a clueless adult. The great part of the job was sitting outside my shack fly fishing for the elusive freshwater walleye. I never caught one, and only realized much later that the reason was the lakes had never been stocked with them. Once again, clueless!

Here in the waters off Catalina Island, I regularly "catch" walleye... but only on film. I'm talking about the walleye surfperch (Hyperprosopon argenteum), one of the many species of surfperch in southern California waters. This silver colored fish often has bluish or greenish tints and may even display a few dusky bars on its side. The tail and anal fins are edged in black. Their scientific name refers to the upward slanting mouth and their silver color. Although they may reach a maximum size of 12 inches at about six years of age, they are usually in the five to nine inch range. A very distinctive feature is the large eyes which give them their common name.

This species is known from as far north as Vancouver Island, British Columbia, to central Baja California although they are only occasional north of central California. Walleye surfperch frequent shallow depths to 60 feet, but are most common above 30 feet. Dr. Milton Love writes that they have been recorded as deep as 600 feet. Their preferred habitats include sandy areas often close to the surf line, but they may also be seen over rocky reefs and in kelp forests.

Walleye surfperch are generally a schooling species, often found in dense collections of several thousand during the day. In our waters I rarely see them in such large numbers. According to Dr. Love, they move out onto the reefs at night to feed at depths above 10 feet. He states they are one of the few species of surfperch on our coast that are active at night and may be one of the most abundant midwater fishes after sunset. Here in the Casino Point Dive Park, I've never seen one at night, but that may in part be due to their lower numbers in island waters compared to the mainland.

This species feeds on small crustaceans which may include krill, amphipods and isopods. They may even supplement their diet with small fish. Predators on them include harbor seals, least terns and both Brandt's and double-crested cormorants. These carnivores receive competition from humans since the walleye is one of the mainstays of recreational anglers fishing off piers. Native Americans also ate them frequently based on bone fragments in their kitchen middens. A small commercial fishery also exists.

Unlike humans, the males of this species mature earlier than the females, but both usually reach sexual maturity in their first year at about 4 1/2 inches in length. Mating is reported to occur in November. Like many in the surfperch family, the males dance to attract their mates. Each species may have its unique repertoire of dance steps. Male humans are lucky if they can master one. I have observed walleye males tending one to several females, almost herding them around as they dance.

Because these are live bearing fish, fertilization occurs inside the female. The male introduces his milt aided by the thickened anterior portion of their anal fin. The embryos develop thanks to nutrients in the egg yolk as well as coming from the mother's body. The gestation period is 5-6 months and the young are born from April to June. Litters may number from five to as many as 19, each about 1 1/2 inches long. They often exhibit narrow vertical bars on their sides. Females are reported to grow faster and live longer than the males... I guess they have at least one thing in common with our own species!

Like other surfperch, their reproductive strategy poses a problem. Since the kids are born as miniature versions of the adults, they tend to hang around the family reefs. Kind of like the apple doesn't fall far from the tree. Surfperch lack the drifting egg or larval stage that might permit the young to seek adventure in far off places. If they don't disperse as young or swim far as adults, this makes it quite difficult to establish new populations elsewhere. This is one reason why some surfperch species are missing from our offshore islands. However, my early research on drifting kelp rafts indicated that some may "hitchhike" from the mainland by hiding from predators under the kelp paddies.

© 2010 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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Walleye surfperch in small groups (top) and males putting on their dancing shoes... er, fins... for the ladies (bottom).

This document maintained by Dr. Bill Bushing.
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