Dive Dry with Dr. Bill

#393: Copper Clappers... and Rockfish

In my youth I first considered becoming a chemist before I returned to my first love, marine biology. Dad and I built a chemistry lab bench and Mom let me put it in the basement next to the freezer (from which I could sneak ice box cookies when my experiments "dragged on"). One of the metals I had in my lab was copper, known to the Romans as Cyprium since it was mined primarily from Cyprus, and of course I had a number of copper salts such as copper sulfate. I also had a collection of pennies, made mostly from the metal copper (except during World War II when steel was used... and after 1982 when zinc became the primary component). By the time I was in college, I worked with coppers on volunteer stake-outs of park district property with the Cook County (IL) Sheriff's Dept. And who can forget Johnny Carson's copper clapper caper... except perhaps the young 'uns who don't even know who Johnny Carson is? Speaking of which, I was shocked to find that a group of media people in "Lost" Angeles did not feel Jacques Yves Cousteau was worthy of a radio "piece" on the 100th anniversary of his birth last month.

Other than Cousteau's 100th, what does that have to do with marine life? Not much! I admit it's quite a stretch, but this week I am going to talk about coppers of a different "color," the copper rockfish (Sebastes caurinus) which I observed and filmed in the cold waters off Santa Cruz Island on a recent dive as a guest of the Roddenberry Dive Team. Now rockfish are generally a cold water group, found mostly at deeper depths in our warmer Catalina waters. I usually have to dive below 100 and as deep as 200 ft to see species other than the kelp or grass rockfish and the related treefish in our waters. Fortunately up in the cold northern Channel Islands, these other species may be present as shallow as 30-60 feet.

The copper rockfish ranges throughout much of the West Coast of North America. It is reported from as far north as Kenai, Alaska, on down to central Baja California in the region of the San Benito Islands. However, they are only considered common from British Columbia to southern California. That puts them at the southern-most point of their geographic range here, and explains why they have submerged to deeper depths in our warmer waters. These rockfish are benthic or bottom-dwelling, and prefer rocky reefs in depths ranging from the shallows up north to 600 feet in the south.

Dr. Milton Love reports that the copper rockfish is also known as the chucklehead, whitebelly rockfish and Never Die (because they live so long out of water). This species comes in such a wide range of colors that it has caused some confusion for anglers as well as scientists (including yours truly!). Interior designers may choose from copper, yellow, white, pink, orange, orange-red, brown, yellow-brown, greenish brown or even black. Henry Ford would have a fit with this fish since he only offered the Model T in "any color you wanted as long as it was black." Sorry, the coppers don't come in baby blue or mauve, at least not to my knowledge (or anyone else's). Individuals found in the northern part of their range tend to be copper or orange while those in the southern end are often yellow-brown to olive. I found both color variants on my dives off Santa Cruz Island that weekend. Based in part on the color differences, scientists used to assign the southern individuals to a separate species, Sebastes vexillaris. They are now known to be one and the same.

"Coppers" have other distinguishing features to assist in identification since color is unreliable. There are two yellowish stripes running backwards from the eyes, although looking at that region from a different perspective you might see a darker band bordered by these two lighter bands running from behind the eye down towards the pectoral fin. In most individuals the rear two-thirds of the lateral line along the side lies within a white stripe. The belly tends to be white, as the name whitebelly rockfish suggests, and the fins are a "lighter shade of pale" (with apologies to Procol Harum).

When hungry, these carnivores select from entree items including crabs, shrimp, octopus and other fish. Given that menu, I would certainly be happy as a guest at their dinner table. The juveniles require something a bit more bite sized like plankton. No thanks. Humans are included among their predators. In fact, these rockfish are a reasonably important target of recreational anglers from the Santa Barbara Channel "way up north" to southeastern Alaska. They constitute part of the commercial rockfish catch and are often sold to Asian live fish markets.

Copper rockfish are generally solitary, and tend to remain in one area but do not appear to be territorial. They will occasionally form small groups. About half are sexually mature at 4-6 years and 13-14" in length with the "late bloomers" catching up by eight years and 16 inches. I'll bet they get teased a lot in school. Spawning is highly variable from late winter to early summer depending on the geographic location and water temperature. Newly recruited young tend to hug the bottom and may also be found associated with drifting kelp. Coppers are said to reach a maximum length of 22 1/2 inches, and live at least 28 years. Apparently they must feel, like we did in the 60s, that "you can't trust anyone over 30." Trust me on that!

© 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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Side views of the northern coppery color variant of the copper rockfish; ambushing a potential "munchie,"
and the yellow-brown southern color variant also seen in the same waters off Santa Cruz Island.

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