Grouper, Garupa, Kerapu

After so much addiction to seaweeds, I got something new to be crazy about. Now, it is the turn of Grouper fishes to attract my attention. Why so much fuse about these group of fishes? First, they always make a good dishes. Second, they always patch a good price especially when it arrive alive at the markets or seafood outlets. Third, due to high demand, it give pressure to this kind of fishes in the natural habitats. Some species already considered in endangered level which trigger some concern among naturalist.

For decades, some grouper species always considered delicacy by some group of people. Mouse grouper for example, not only exotic by look but superb by taste. I sincerely understand why some NGOs give suggestion to ban the export of that species due to overfishing effort done. However, as in many cases, I strongly believe that the effort to propagate the species is more vital to reduce the potential of resource depleting and reduce the pressure on wild caught overfishing than the move to ban the export.

I had chances to visit some commercial as well as small scale fish hatcheries that producing grouper fry in Malaysia, Indonesia, Thailand, Taiwan, Singapore and China. From my observations, those hatchery operators seriously giving impacts to reduce wild caught grouper by producing millions and millions of grouper juveniles each year. However, since demand always faster than production, it does not able to totally eliminate the pressure. So, more serious effort needed to ensure equalibrium met. For me, more scientific research required to solve the need of the market and enough supply of this fishes so that these delicacies will be on the table for those who are crazy for their tender meats.

There are many species of groupers that are popular and in high demand in oriental market. Giant Grouper (GG), Tiger Grouper (TG), Mouse Grouper, Leopard Grouper, Green Greasy Grouper are among the commonly known groupers that being produced or exported from South East Asian Countries. In recent years, the hybrid of GG and TG becoming popular in the market, loved by the consumers and prefered by the culturist too.

Most of the groupers are proterogynous hermaphrodite. First, they were born as functional female but later will change to fuctional male. This phenomenon make the situation a little bit tricky to get consistent supply of certain sex of the broodstock for aquaculture purposes. However, the hormone inducement have help the hatchery operators to solve the problem, partly.

Okay, so why did I so obsessed by these creatures? First, I always wonder what stimulate the sex changes of the fish in the wild. Surely, there are no hormone treatment given deep inside the ocean. So, what was the stimulating factor(s) for sex inversion? I have no idea about what exactly the factor(s) involved to create such an important impact to the survival of the species,

Second, I always want to know what trigger the spawning activity among the grouper fishes? Was it salinity changes? Temperature? Certain food consumed? Lunar movement? Light intensity? I was so obsessed by the potentials of manipulating such factors to create induce spawning behaviour of the species naturally rather than hormone inducement methhods.