Sex and the Sea

The advantage of being a bio freak is that you occasionally come across something weird and strange to do with life. But not necessarily anything to do with human life. The sex (as both noun and verb) in the sea is far more bizarre and colorful than our own.

Consider the Laboides dimidiatus of the Great Barrier Reef. The 10-cm, pugnacious male defends his harem 7-9 females from other males. One of the females usually dominates the others and the male is particularly aggressive towards her, since she threatens to assume his dominance and as it happens, his gender. Within hours of his death, she takes over and presides over the harem. Within a month the female actually becomes a fully functional male. This will go on and on in a never-ending feminine quest to reach the top of the dominance hierarchy.

For the giant grouper, which reaches 3 meters and 300kg, gender is determined by age and size. The young and dainty are females. As they grow, b/w the ages of 3-5 they become males. So the oldest are all males. (Although the females never reach the stature of males, at least they don’t have to worry about growing old.)

The quickest sex change takes place in the belted sand bass in the Gulf of Mexico. One twists into a “S” shape and spreads his fins in view of a neighbor. Our twisted courtier is male and the interested observer is probably a female. He ejects sperm, she eggs and another pair of reef fish has mated. It is not over yet. This is just the beginning. Now the male plays the shy female and the one time lady becomes a male. Now she ejects sperms and he ejects eggs.

The Amazon molly consists solely of females. During mating, the unisexual females use subdominant males of a related bisexual species. These borrowed lovers only activate the egg development and none of their genes are actually incorporated. The offspring of this half-hearted mating turn out to be females, all very much alike.

Then there are males who are just gigolos. The male angler fish searches for a female to support him. If he fails, he dies. (No counseling exists, I guess). If he finds a mate, he makes sure he doesn’t lose her by biting deeply into her head or belly- hanging on for dear life. And he degenerates into a complete parasite, even sharing the female’s circulatory system to stay alive. In the north Atlantic, 1.2 meters long females have been found with 8cm husbands

Guys, take heart. Not all marine males are pathetic lovers. Take octopuses. The male 1^st caresses his partner and she runs through a series of colors and blushes like a school girl. When she is ready, he places a packet of sperm inside her body cavity. In spite of not being a pathetic male lover as opposed to the rest of the sea, they remain mated only for a day.

Mass spawning is found in the orgies. Every other week at the full and new moon, from March to august, 1000s of these fishes ride waves to the beach. Arching her back, the female wiggles into the damp sand till only her head is exposed. Then she lays anywhere from 1000 to 3000 eggs and several males gyrate wildly around her, fertilizing them. All must be accomplished in 30 secs before they ride the next wave back to sea.

Fidelity is rare but not extinct. Tiny shrimps off the coast of Japan live their lives together. As they reach maturity, they squeeze into “Venus’s-flower-basket” sponge to feed and then too large to get out again, they remain trapped forever. Appropriately these sponges are a wedding present in Japan, symbolizing ever lasting union.

These mechanisms ensure that with each generation, the probability that at least a few of the progeny will survive increases, no matter what the environmental conditions. Thus sex is nature’s response to uncertain and changing future. For that- whether we swim in the sea or walk on land- we can all be grateful.