Dive Dry with Dr. Bill

#175: Return of the "Big Head"

Hard to believe, but this is my 175th "Dive Dry with Dr. Bill" newspaper column. However the "big head" in the column's title has nothing to do with me (well, at least most of the time). I've often thought of compiling the "Best of Dr. Bill" into a book to sell here in Avalon and in dive shops on the mainland. Only two drawbacks. The first is money to fund its publication. The second is that the book could rival the length of my 709 page Ph.D. dissertation, which requires it's own shelf at the UCSB library. Few visitors would want to carry that home with them unless they were professional weight lifters! On to the "big head" referred to in the column's title.

Water temperatures last winter were unusually warm. I don't remember bottom temperature reaching lower than 56 degrees, which is unusual. Another unusual thing was the absence of some colder water critters like the subject of this week's column, the cabezon. Although not overly common, I always encounter these fish in the dive park during the winter months. Last year I didn't see my first one until June... at a time when bottom temperatures took a sudden drop. So far this winter I haven't seen one either.

Cabezon are large fish varying in color from black to brown to red to green. Dr. Milton Love states that 92% of adult males are reddish and 97% of adult females are green. Since the one I observed last June was green, I'm going to guess (with a high level of confidence) that it was a female. Cabezon have skin projections or flaps above their eyes and another above their mouth. The name cabezon means "big head" and is a very appropriate common name for them. They are hard to confuse with other fish species although they do bear a resemblance to the scorpionfish.

These fish are known from Sitka, Alaska, south to central Baja. They are most abundant from Washington to southern California. Cabezon prefer solid substrate whether it be a rocky reef, or manmade structures like wrecks and oil platforms. Most are benthic, found on the bottom from shallow depths to nearly 400 feet although those below 100 feet are rare (and I don't mean when cooked). It has been reported that they tend to migrate to deeper water as they increase in size. They do not move around a lot, preferring to remain near a home reef. High gas prices aren't a factor in their lack of mobility.

Cabezon may reach lengths of 2 1/2 feet with the females living longer, growing faster and reaching larger sizes than the males. However, they take longer to become sexually mature (3-5 years vs. 2-3 years for the males). Two year olds are about a foot long, but it may take another seven years for them to double in size. The record length for a cabezon is 39" and more than 25 pounds. Maximum life span is believed to be 17 years.

Mating reaches a peak in southern California during the colder months (October to April) but may happen at any time during the year. Females produce 50,000 to nearly 100,000 eggs each season, and may spawn twice during that period. Nests measuring up to a foot and a half in diameter and 4" deep are created, occasionally as high as the intertidal zone. They often use the same nest every year. Some report the nests are on on exposed surfaces while others state they are in crevices and under rocks. Like the adults, the eggs may vary in color from red to green to yellow (all the colors of a stop light which, of course, we don't have here on the island). The eggs are known to be poisonous which offers them some protection from predators (unless they have cast iron stomachs).

The eggs are guarded by the male until they hatch. The larvae drift in the plankton, but rarely more than 50 miles from shore. They continue growing until they are about 2" long. At this point they leave the plankton and settle in tide pools along the shore. Here they feed on small crustaceans including shrimp and crabs. The adults prefer crabs but will also eat other fish, lobster, octopus, squid and even abalone. According to Dr. Love, the cabezon is able to knock abalone off rocks, swallow them whole and later spit out the shell! I'm assuming these abalone are not of legal size! Cabezon are "sit and wait" predators, resting on rocky surfaces with a fair degree of camouflage, then lunge towards their prey when it comes near. In turn, the juveniles are eaten by rockfish and lingcod, and adults by sea otters and marine birds.

Cabezon are frequently caught by fishers fishing from shore or piers, but also from boats. Their flesh is blue in color, possibly due to copper compounds in their food. The color disappears when the fish is cooked. There is a limited commercial fishery for this species. They were also eaten by Native American tribes along our coast.

I wrote a column about this species a few years ago. I usually try not to repeat a subject, but the absence of cabezon last year (and so far this year) has wider implications. Why was it absent, or at least not observed by me, during the winter months? Do the unusually warm winter water temperatures last year signify anything important? Are they staying down in deeper and colder waters. Why did the species reappear (along with colder water) last June. Enquiring minds want to know!

© 2006 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. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe" or "Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Cabezon dropping from its perch as I approach, female (green) cabezon; the cabezon's namesake
"big head" seen from above, the head showing eye and cirri above it.

This document maintained by Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia