Dive Dry with Dr. Bill

#275: Sargo

A while back I wrote about the California salema, a local member of the grunt family which is perhaps more common in tropical waters. There is another local grunt in our waters (and I'm not referring to the ones at Camp Pendleton). It is the sargo. This is another schooling species, although they are often found in smaller groups than its relative the salema.

Sargo have a very obvious dark bar running from the upper surface below the dorsal fin to the start of its belly. Although the rubberlip seaperch and pile surfperch also have black bars, their body shape is different and they don't have a dark edge to their operculum. The body color is generally silver, although it may show hints of copper or gold. The young have two dark stripes along the side of their bodies. These disappear and the dark vertical bar takes their place at about six months of age.

These fish are found from central California, where they are rare, through southern California where they are common and south into southern Baja and the northern portions of the Sea of Cortez. Their northernmost location is Santa Cruz, California. The population in the northern Sea of Cortez is isolated from the rest of the species, creating what is known as a disjunct distribution. The major populations are separated by areas where they are not located, thus restricting gene flow. They are also found in the inland Salton Sea, having been introduced there in 1951. Sargo have been successful there because they can tolerate waters with somewhat higher salinity than ocean water, which is about 35 percent. However, if the salinity exceeds approximately 4.2 percent, it drastically affects their metabolism and feeding patterns.

Sargo prefer habitats with rocky outcroppings or kelp forests, and depths of 10 to 50 feet although they have been found down to 200 feet. They should not be confused with the sargo class of US submarines that were built in the late 1930's. These subs were the first sent into action after the bombing of Pearl Harbor, and had a distinguished record during World War II. After the War they were used primarily for training. The sargo fish carries no torpedos, so they are easily distinguished from the subs. Nor should they be confused with Sargo Subs in Oregon which serves delicious sub sandwiches according to restaurant reviewers.

Although schooling fish often eat abundant plankton to support their higher densities, the sargo appears to be more of a bottom feeder. It takes crustaceans including isopods, amphipods and shrimp in addition to kelp scallops. In turn, they are eaten by least terns. Sargo are considered a sport fish in southern California, and are occasionally marketed commercially. Fishers in the Sea of Cortez don't find them as appealing a catch, perhaps because of their smaller size there.

Sargo are larger than many other grunts including the salema. The largest reported was almost 20 inches. One measuring half that size is about four years old and a 17" inch fish is about 15 years old. Those in southern California may reach 5-6 pounds. The population in the northern Sea of Cortez is generally of smaller size, rarely exceeding 12 inches in length.

They are believed to mature in their "terrible two's" at about 7 inches in length. The eggs are released into the water column and drift with the currents near the surface. The young move inshore into shallow waters in late summer and early fall. There they often school with young salema and black croaker which have a similar appearance in their early stages. And, of course, Dr. Bill is right there swimming alongside them, enjoying the warm water.

© 2008 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 "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass," "Common Fish and Invertebrates of the Sea of Cortez" or the new "Sharks and Rays of Southern California" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Schools of sargo (top) and close-ups of individuals (bottom) showing the dark bar and lateral line.

This document maintained by Dr. Bill Bushing.
Material and images © 2008 Star Thrower Educational Multimedia