Dive Dry with Dr. Bill

#297: Gentle Giants... Let Them Be

During summer I usually have a backlog of columns already written since it is the busiest time of the year for diving. I wouldn't want to deprive my readers of another chance to learn, and laugh, because I was just too busy underwater. However, I'm going to write a new column for this week, focusing on something that concerns me. I usually don't worry about too much... except the environment, my finances and my love life (or lack thereof) so bear with me.

I spent all of July focused on editing my new octopus and squid DVD, and only did eight dives the whole month. With that task accomplished, I donned my wetsuit and boarded SCUBA Luv's King Neptune for a weekend of diving... and did 10 dives over the three days. Captains Mike and Mayor Bob took turns at the helm, with divemasters Mike and Devin doing their usual great job of taking care of the divers. What really thrilled me was that I got to do four dives this weekend with one of my all-time favorites. No, not the lovely lady of my dreams... I dove with up to 13 of our incredible giant or black sea bass, known as Mero or Lubina Gigante in Mexico.

New readers of this column may not be aware of the thrill I get spending time with these well-mannered monsters. When I first started diving Catalina back in the late 1960's and 1970's they were in sharp decline due to commercial and sport fishing for the species. Heck, spearing these critters is even easier than hitting a garibaldi... after all, they are almost the size of a VW bug. It would be like hitting the broadside of a barn... which even I can do despite my lousy eyesight. Fortunately, beginning in 1982, the State of California instituted a series of restrictions on fishing activities that were affecting these "bass" (actually members of the wreck fish family Polyprionidae rather than the temperate bass or groupers as many think). Today I see them on a regular basis.

This is one of the relatively few conservation success stories in our waters. Hopefully future measures taken under the Marine Life Protection Act (MLPA) will prove equally successful for many other species in southern California. It is interesting to note that a much earlier scientist with an affinity for Catalina, Dr. Charles Frederick Holder of Tuna Club and Rose Bowl Parade fame, urged conservation measures for these fish back in 1910 when they, rather than marlin, were the target of many recreational fishers who used stout hand lines to catch them.

I first sighted a giant or black sea bass in the Casino Point Dive Park nearly 10 years ago. Some of my earliest filming of the courtship behavior of this species occurred there and in Lover's Cove where there was a group of them that gathered each summer. The mating group in Lover's Cove eventually moved on a few years later, apparently to the south of Avalon. Since SCUBA divers aren't usually allowed there, I'm not sure what caused them to seek "greener pastures" for their "private moments." Fortunately there is no fishing activity there, so that can't be a cause. Perhaps snorkelers discovered them. Possibly it was the frequent tour boat traffic. Until I can speak the language of Stereolepis gigas (their scientific name), I may never know.

Another courting group was centered near Italian Gardens. Many dive boats from the island and the mainland have visited this site over the last 10 years or so. This year it appears that the courting group there has dwindled in size, perhaps due to such intense interaction with divers. I say courting group because no one to our knowledge has ever observed, much less filmed, their actual mating behavior. Years ago dive buddy Vicki Durst and I were observing them out near Ring Rock while the male rubbed the female's vent with his body, apparently a prelude to mating. However, before taking it a step further, the fish swam off to a more discrete location. That was during daylight, and the assumption has been that these huge fish mate at dusk, during the night or possibly at dawn.

My dives with these fish were at a "new" site up the coast. Perhaps this is where some of the bass from Italian Gardens went, so I'll have to compare video footage from past years and see if I can recognize any distinguishing marks. After all, they don't carry personal ID cards since they don't drive or go to the Chi Chi Club. It is believed that the giant sea bass educate their young regarding the location of historic courting and mating locations. They are thought to show fidelity to such sites unless they are disturbed. Young bass take about 12 years to reach sexual maturity, at a bantam weight of only 50-60 pounds. Of course even then the big boys keep these small fry away from the ladies by chasing them off. I'm a big boy, but somehow have never managed that feat with the ladies of our species. Since it takes time for the young to mature, they may get confused when the elders of the group decide to move to a new courting site. It may even be possible to disrupt their reproductive activities through too much interference.

Why are the gentle giants relocating to engage in mating? Three years ago I wrote in this column of my concerns about diver interactions with the fish at Italian Gardens. Too many divers approach them quickly and make them flee. They often wave their hands about (as new divers will) which can scare them. Worse, many want to touch the fish. Even the light from an underwater camera strobe can frighten them away, as I've recorded when other divers take still images while I am filming the bass. I was concerned back then that these interactions might cause the fish to move elsewhere, which they appear to have done. We divers have to be careful and exercise good judgment when diving with these wonderful fish. The very best method is to sit still and let the fish approach you since they are often quite curious about us as well. If one must get very close, do so slowly and from a position even with, or below them and from the side. I have been able to approach them within inches this way and have had encounters as long as 50+ minutes with individual giant sea bass.

I've also noticed more fishing activity at the new site than I remember in previous years when the bass were not there. This may be due to my poor memory, or just a coincidence. Fishing activity can certainly affect the bass' behavior, although in almost all cases it is unintentional on the part of the fisher. I see a number of giant sea bass with fish hooks in their mouths and trailing monofilament, as well as damage to their gill covers which could be caused by strong fishing leaders. Now, almost all fishers are targeting other species, usually much smaller ones, since the take of giant sea bass was forbidden in 1983. I have heard of some mainland anglers recently who have taken them illegally. In 2005 the State instituted a $1,000 fine and up to six months in jail for possessing one. Most anglers are fishing with much lighter tackle for kelp bass, sheephead and the like, but even a "small" hook in the mouth or a ripped gill cover could be rather distracting to a fish intent on mating. I would love to see some of the historic courting sites protected from fishing during the months when the bass are present.

To be objective (as all scientists should be), there is another, natural explanation that might explain the relocation of these bass. It is possible they move to new sites every so often so that natural predators like great white sharks don't find them as easily. Last year I filmed a giant sea bass off Long Point with a large crescent shaped scar on its side that must have been from a great white attack. My fangs are nowhere near that big. I've heard that two fishers, including our own Mike Hiniker, have observed or filmed great whites feeding on these "super sized" meals off our coast. I really should write a grant to study these giant fishies (the bass, not the sharks). It is also possible the groups shift location in response to an increasing density of giant sea bass.

So I'm expressing my concerns about our gentle giants once again. However, there were two other very exciting observations on my dives last weekend. At Little Gibraltar (also known as the Bill Kroll Hi Spot for our former sheriff's deputy who loved to free dive there), I found two flatworms who were very cooperative, letting me get several minutes of footage of them. I don't usually get a chance to film these invertebrates so I was pleased. The other sighting occurred at Garibaldi Reef. I was doing my safety stop at the edge of the kelp forest, and filming schools of baitfish there. As I prepared to return to the King Neptune, I saw two white sea bass swim off towards the shallows. That night when I edited my footage from that dive, I discovered I caught one of them swimming through the school of bait... the first time I've recorded this species on video, and only the third white sea bass I've ever seen underwater. The black, and white, sea bass and the flatworms really made for a great weekend!

© 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!

Giant sea bass swimming and hovering midwater, sneaking in close to get a good look at... me,
and Dr. Bill filming a large sea bass (image courtesy of Tim Baskin) .

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