In the Group(er)

By Anonymous -

It’s a common misconception that groupers refer to a single species of fish. But in fact, they are a large group of species found in the family Serranidae. However, Serranidae also includes sea basses, so don’t confuse them! Many groupers fall within two genera, Epinephelus and Mycteroperca. Groupers are commonly found in warm waters such as the Caribbean Sea and Gulf of Mexico. Interestingly, groupers have a unique life cycle. When male populations are low and the need for sperm in the ecosystems is high, the females will often change sexes to satisfy the reproductive needs of the population. This is termed as being a protogynous hermaphrodite.
Sickelfish Grouper- Dermatolepis inermis
arkive.com
Groupers are a common dish in many countries, and therefore are an important economic resource for fishermen. But sometimes groupers are toxic to humans due to their symbiotic relationships with dinoflagellates. In other words, Groupers have a relationship with a microscopic organism where both organisms benefit. The dinoflagellates are able to synthesize food for the fish but then also get to take in some of the nutrients of the food. So each organism helps the other in order to get what they need. A byproduct of this relationship is that the dinoflagellates secrete a toxin that accumulates in the fish skin. If the toxin increases to high enough levels, the fish becomes poisonous to humans causing Ciguatera, which can be fatal.
Eightbar Grouper- Epinephelus octofasciatus
arkive.com
A prevailing theme in ecology is the idea of “cost benefit.” This means that organisms often have to decide whether foraging for nutrients, and therefore growing, is a better or worse decision than hiding and avoiding predators, and not foraging for nutrients. Scientists have found that small groupers tend to ‘hang out’ in well protected, high algae growth areas where it is harder for predators to see them. Once they are big enough, they move to places that are more out in the open because they are now able to fend of predators easier. Therefore, where their habitat resides is indicative of their behavior and ability to protect itself.
                            Nassau Grouper (bottom fish)- Epinephelus stratus
                                                     mikegil.com

One unique species of grouper is the humpback or panther grouper (Cromileptes altivelis). They are found from the southern islands of Japan to Australia. The humpback grouper dwells in lagoons, well developed coral reefs, and tide pools. Juveniles of this species often nurse in seagrass beds or lagoons formed by fringing (shallow) coral reefs. They can grow up to 70 cm in length and live up to 14 years. Humpback groupers feed upon small fishes and crustaceans. As stated earlier, the species is a protogynous hermaphrodite. According to the IUCN Red List, the species of grouper is listed as vulnerable. They are threatened from commercial industry (aquarium trade and human consumption), habitat construction, and from their general low population abundance in the wild.


121863-004-CDB655A8.jpg
Panther Grouper- Cromileptes altivelis
http://www.britannica.com/animal/grouper
Another unique species is the goliath grouper (Epinephelus itajara). As the name alludes to, it is the biggest species of the groupers. However, it is not a gentle giant! They can reach up to 8 feet in length, and use their size to intimidate other fish. Also, they are able to vibrate their swim bladder to make a growl-like sound. Imagine running into that fish! just like other types of groupers, they are susceptible to overfishing. in fact, in just the last 10 years, about 80% of the population has been reduced.


Epinephelus-itajara-01.JPG
Goliath Grouper- Epinephelus itajara
http://www.flmnh.ufl.edu/fish/discover/species-profiles/epinephelus-itajara
Groupers, like most fish populations, are facing endangerment and extinction. They are a popular food source for cultures all around the world. Already, 20 different grouper species are facing extinction because of their demand. The U.S. government now has a limit to how many groupers a fisherman is allowed to keep, among other conservation efforts.
Limited Kept Groupers
sanibelcaptivaoffshore.com












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