Thursday, September 28, 2006

Sex Changing Tendencies

The black sea bass (Centropristis striada) is best known for their ability alter its sex. According to this issue of Copeia from 1981, the sea bass species undergoes gonadal changes to produce secondary males. These sex changes occur throughout the year. As described here, there is a drop in the number of individuals undergoing sex change during the spawning season. This is most likely linked to the sea bass's energy cycle. It would make sense if they need to conserve energy to reproduce. Sex is definitely an energy drainer. On the other hand, there is a peak in the number of individuals in transitional phases. As a result of theses peaks and troughs in their sex change cycle there has been little success in the aqua culturing this over fished population of sea bass in New England according to David Berlinsky of the University of New Hampshire.

According to the same Science Daily article, much of the aquaculture capital goes into buying black sea bass thoroughbreds. Due to the sex change phenomenon, most of that capital is wasted as new females must be bought to compensate for the offset male to female ratio.

Funded by the New Hampshire Seagrant, assistant UNH zoology professor Berlinsky along with GreatBay agriculture discovered that temperature triggers the sex change in black sea bass. The partnership was successful in also discovering that female sea bass were more likely to undergo the sex transformation when there was a lack of males in the artificial environment. The opposite scenario would occur when the tanks are crowded; the females would turn into males.

Currently, further hormonal research is being done to see if estrogen and 11-ketotestosterone levels can control these sex altering happenings in the black sea bass aquaculture community. If successful, the black sea bass will become a worthwhile investment for aqua culturist as well as a more affordable meal for consumers.

Posted by T2 (4)


At 2:35 PM, Anonymous Anonymous said...

I read another article similar to this. It was study of fish that lived in the coral reefs. The scientists observed the same things you mentioned. If there were two males together, the smaller male would go through the sex change. This was to ensure that there was a mate if there wasn't a big selection. These fish went through the sex change because they wouldn't leave their territory. I didn't know that there were other fish who did the same thing. Very interesting.

Posted by Karisma (4)

At 4:18 PM, Blogger PWH said...

This was by far the most interesting post to me out of all the others; not only interesting but fascinating as well. It's crazy to think that humans pay money to undergo sex changes where as these black sea bass have the capability to do it on their own. Just a random fact that you didnt mention was that the sea bass actually begin life as females and then change into males between 2-5 years of age. Still, I am interested in learning about any further developments or discoveries in the research of this species of fish.

commented by CMT

At 8:59 PM, Blogger PWH said...

This post has given some valuable information and was of most significance to me. I just have recently become interested in fishing and identifying species of fish over the summer. I never knew that this species of bass undergo this sex change phenomenon. It makes sense though to ensure their survival as a species in the wild. I remember from a show on Animal Planet, that this also happens in other fish such as the clown fish where the status of a fish is determined by its size. The largest clown fish is the breeding female and the second largest is the breeding male. If the female was taken away, the breeding male would take her place as the breeding female. This behavior must be both connected to the basic evolution of some fishes and the changes that occur in the environment. Just curious, are fish the only vertebrate to do this or are there other animals capable of doing this in the wild?

Posted by Chamel413 (4)


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