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Dive Dry with Dr. Bill

#513: Perch Porn

Back in the days when I taught biology at the former Catalina Island School, one of the favorite upper level courses was my "Animal Behavior" class. Students would read extensively on various topics on that subject, then roam the hills or dive the waters to study the behavior of critters they chose to write their term paper on. Occasionally I'd even use their own animal behavior to illustrate my lectures! Of course it will come as little surprise that one of the favorite sections was on reproductive behavior. After all, if critters don't reproduce... the species goes extinct. And we don't want that to happen. Well, except maybe mosquitoes (and we did read a paper on their sex life).

Now they say with humans that a man's fancy turns (from munching?) to love in the spring. There are a lot of critters take take their cues from the warmer temperatures and longer day lengths to do just that. I've already written extensively this year on the love life of the garibaldi and the giant sea bass. With water temperatures cooling down now, these fish abandon love making for that other "M" word... munching.

However, there are species that seem to prefer the cooler times of the year to mate. Maybe it is the increased need to snuggle and stay warm! Recently I've been observing a lot of amorous activity in the dive park. No, bikini season is pretty much over (sigh). I'm talking about fish. The giant kelpfish are mating and just like the garibaldi, the male is saddled with child care duties and tends the nest. Since the kelpfish use thick stands of seaweed to mate in, they do it with some discretion and it is much more difficult to film.

However, the perch family apparently has no shame. They court (and spark) right out in the open. Well, some of them exhibit some modesty by attracting and seducing their mates within the kelp forest, providing a modicum of cover for their love making. I try to hover nearly motionless between the fronds to film them, feeling like a real voyeur. Two of our local species that have been my subjects recently are the kelp surfperch (Brachyistius frenatus) and the black perch (Embiotoca jacksoni). Often I will see them both in the same space, ignoring one another as they pursue the female of their own species.

The much smaller kelp surfperch courts rather frenetically. The male swims alongside the female twitching his body and swimming spasmodically alongside her. Sometimes the female tolerates this erratic erotic dance, but other times she does a 180 and swims off in the opposite direction. I would imagine that the male's small body is awash with the equivalent of testosterone and he just can't control himself. Or maybe he hears the "music" of one of those bands the kids listen to today. When I taught at the Toyon School, many of my male students behaved similarly!

The male black perch must have a cooler head. His approach to the female is usually slow and steady... few abrupt movements. He reminds me of some of those cool cats with the smooth moves that often got the ladies. The music in his ears must be more like the Big Band era in the Casino Ballroom. He slowly swims over to a potential mate and tilts his body so he is literally swimming on his head. I almost wonder if they watched Cal Worthington commercials... hey honey, "I'll stand on my head to make you a better deal." He slowly swims alongside her, drifting in and out of the kelp fronds. Occasionally I see a male courting two ladies at once. Reminds me of when I courted identical twins... OK, so it was 25 years apart.

The third perch species currently indulging in such behavior is the rubberlip seaperch (Rhacochilus toxotes). Like the black perch, he is a "smooth operator" (thank you, Sade). He also does a slow dance with his head held down. I've seen males of this species tending a number of ladies so I guess they believe in polygamy. I also see males slowly swimming alongside one or more females near the bottom. We refer to this as tending a mate. This species engages in these behaviors right out in the open. I guess PDAs are allowed in their world.

Now despite spending hours many observing these three species courting over the years, I don't remember ever seeing actual spawning. I had the same problem filming giant sea bass with the Japanese film crew... lots of courtship but no spawning. Now you may remember that garibaldi have absolutely no shame. Capturing them "in the act" is easy... at least at the right time of the year. Come to think of it, although I see plenty of courting behavior among humans in our local establishments at night, actual spawning in public is almost unheard of... well, except during Buccaneer Days. I guess humans and most fish aren't that different after all!

© 2012 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). 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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Black perch, standing on his head to make her a better deal; kelp surfperch and erratic courtship dance.

This document maintained by Dr. Bill Bushing.
Material and images © 2012 Star Thrower Educational Multimedia