Dive Dry with Dr. Bill

#148: An "African Safari" Here at Home?

I've never been that intrigued at the thought of traveling to Africa to go on a safari. Lions, elephants, tigers, zebras and the like just aren't my cup of tea. I'm much more interested in sea "lions," "lion" fish, "elephant" seals, "tiger" sharks, and the subject of this week's column, our own "zebra" perch. However, I'd love to go to Africa to dive... the Red Sea, the South African kelp forests, Mozambique, Tanzania, Mauritius and Madagascar all hold intrigue for me. Until some nice foundation sends me a ticket, I'll just have to settle for the green, green seagrass (and brown kelp!) of home.

Imagine my complete surprise when I looked through fish expert Dr. Milton Love's book Probably More Than You Want to Know About the Fishes of the Pacific Coast and could not even find a reference to the zebra perch, a fish observed with reasonable frequency in the waters of Catalina's dive park! In fact it is reported from Monterey south into the Sea of Cortez (where they are known as chopa bonita). Did I catch you on this one Milton? I then discovered that even Paul Humann did not include it in his Coastal Fish Identification book. I had to turn to my field guides from Mexico and the Sea of Cortez to find information on this species. They are considered a subtropical, rather than temperate, species.

Although referred to as a zebra "perch," this species is actually a member of the sea chub family which includes the opaleye and halfmoon (sometimes called the Catalina perch). There is a true perch called the zebra perch but it is a freshwater species. One of their distinguishing features are the vertical stripes (usually 10) from which they get their common name. These stripes or bars are less distinct in juveniles than in the adults. Another characteristic is the absence of scales on the head region (although this requires the close inspection only a diver, or a fisher, can give).

Like other sea chubs, the zebra perch is largely a vegetarian, and appears to feed on algae and kelp. How appropriate for a resident of California where vegetarianism is popular! I have read that these are a good tasting fish (unlike their relatives, the opaleye). However, I must admit that I have not tried them myself. How could I eat my fine finny friends? Let's see... baked, broiled, barbecued, poached, pan fried, etc., etc. One report on the Internet stated that one fisher in Santa Monica caught zebra perch using moss as bait! Others use frozen peas or corn, consistent with their vegetarian nature. Fishers report experiencing occasional runs of this species in shallow mainland waters.

Individuals may reach a foot and a half in length, although those from the Sea of Cortez are reportedly smaller in size (perhaps because there is less algal food there). Zebra perch average about 3-4 pounds as adults. They are generally a shallow water species (less than 30 feet) and often are found near the bottom. However, when in schools I often see them up in the kelp canopy. Zebra perch are said to be a schooling species. However, I often see them individually or in small groups in the dive park. During summer they often form larger schools, which I assumed were related to reproduction. Not much is known about their mating behavior, which appears to be as much a mystery as my own!

I did note a scientific report in the Bulletin of the Southern California Academy of Sciences which stated that zebra perch have increased in the southern California Bight (Pt. Conception south) in recent decades. This would be consistent with two facts. First, as stated previously, zebra perch are subtropical, preferring warmer waters (divers might call them WWW's... "warm water wussies"). Second, water temperatures in the Bight showed a long-term increase following an El Nino event in the late 1970's. The consistently warmest waters off Catalina are those from Long Point to the East End, which includes Avalon and the Casino Point Dive Park. We would expect any increase in zebra perch to be prevalent in this area. Quite frankly, my Old Timer's doesn't allow me to remember how frequently I saw them here before 1977. Actually, it often prevents me from remembering why I walked into the other room on the rare occasions I leave my computer (other than to dive)!

These fish are a good example of how the distribution of living things can be affected by even local conditions. The study of such distributions is known as biogeography, and has been a research interest of mine since my Harvard "daze." Catalina's 54-mile coastline offers a wide range of environmental conditions such as different temperature, wave exposure and water clarity. Warmer water species like the zebra perch may be more abundant at this end of Catalina's leeward side. Colder water forms may be more abundant in other areas. For example I never see painted greenlings in the dive park, yet do find them at colder Bird Rock. Another colder water species, the lingcod, is "never" encountered in the Dive Park but can be seen at Farnsworth Bank on the windward side (and other locations). Good divers, and good fishers, will know what environmental conditions their desired species frequent and go there to find them.

© 2005 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. Buy my "Munching and Mating in the Macrocystis" DVD so you can take Dr. Bill home with you... we'll both be glad you did!

Zebra perch with contrasting vertical stripes; individual with less obvious stripes;
schools of zebra perch often seen in summer months.

This document maintained by Dr. Bill Bushing.
Material and images © 2005 Star Thrower Educational Multimedia