As humans we think of men and women as entities with a fixed genders. Other species do not see things the same way. Fish do things a little differently from what we might think of as normal. Most of us along the Gulf and Atlantic coasts have eaten grouper for dinner or in a sandwich at some point in our lives. But, did you know that most groupers change their gender as they mature. They are called protogynous hermaphrodites.Most or all of the groupers and seabasses are born female but as they mature they change into males. Some species adopt a herd like breeding practice with a dominate male doing all or most of the breeding with several sub-dominate immature males in the wings. The domain male is the most aggressive and under fishing pressure will be quickly caught. This tends to breakup the spawning aggregation if it is late in the season but if it happens earlier on one of the sub-dominate males will quickly mature and take over as the dominate male.If you keep on fishing these aggregations sooner or later you will run out of males. The absence of enough males results in the females changing into males. If the fishing keeps up they will change into males at an early and early age resulting in fewer eggs for spawning. The younger females produce fewer eggs.The reason for the evolution of protogynous hermaphrodites is to enhance the chance for successful spawning opportunities. In the Caribbean the Harlequin Bass is a simultaneous hermaphrodite. This means that they can change sex at will throughout their life. Cannot find a date – make a change.Some of the anglerfish have an odder way of doing things. Anglerfish sit on the bottom waving a small fin that looks like a worm to attract its prey. As with most fish the female is larger than the male. In this case much larger. These large females do not have any problems finding a male. When the female anglerfish starts to mature the smaller male physically attaches to the females body. He becomes a part of her – though he retains his own identity. When the female is ready to breed she signals the male and he complies. Talk about a kept man.There are a very few species of fish that are monogamous and mate for life. The clown fish is one such species. The mated pair will make their nest among the stinging nettles of anemones. They are immune from the stings due to thick mucus covering their bodies. Their young are afforded protection by the anemones from predators and the adult clownfish, which are very aggressive, will drive off fish that try to prey on the anemones. When one or the other of the mated pair dies the other never takes another mate – true love in the fish world.
Think Global – Act Local!