From 1997-2005, our researchers collaborated with Florida State University's Institute for Fishery Resource Ecology (Dr. Chris Koenig and Dr. Felicia Coleman) to monitor the status and recovery of Goliath grouper. This Goliath grouper research program investigated juvenile and adult Jewish abundance, distribution and migration patterns; their age and growth; and their habitat utilization.
With the help of Don Maria we have tagged over 1,000 adult Jewish and have observed aggregations of Goliath grouper in both the Gulf of Mexico and more recently, the South Atlantic. Posters created by the Center of Marine Conservation help disseminate information about our project and its requirements, highlighting our tagging study and the morphology of Goliath grouper.
Given that these groupers were afforded protected status, researchers worked to utilize and develop novel non-lethal techniques to procure and analyze biological samples for life history information. Researchers have also determined that soft dorsal rays hold promise for aging older fish (Marie et al., 2008).
These casualties, resulting from red tide, gave our biologists a unique opportunity to collect a multitude of biological samples, without having to sacrifice healthy animals. From these decomposing carcasses, biologists were able to record length for use in an age/length relationship, and were able to extract monoliths and remove dorsal spines and rays for comparison of hard parts in age and growth analysis.
Tissue samples were also removed and sent to the Florida Marine Research Institute, so they could evaluate the level of red tide toxin. The sampling trip gave these biologists an opportunity to educate the curious beach goers about red tide and Goliath grouper (a few of which had been misidentified as baby manatees).
Attempts to evaluate the data needed to assess the status of these depleted stocks and develop rebuilding plans present unique challenges. In 2010, the Florida Fish and Wildlife Conservation Commission and NOAA Fisheries convened a benchmark Goliath grouper assessment for the continental U.S. population.
When you think of the largest fish in the ocean, images of sharks, marlins and even tuna probably come to mind first. Another one you’d be wise to start considering is the Atlantic Goliath grouper, a huge saltwater fish that leisurely swims in reefs and mangroves between North Carolina and Brazil, and also those along the West African coast.
Goliath groupers, which mostly feed on crustaceans and smaller fish, have been known to weigh in at over 700 pounds. Atlantic Goliath Grouper, by Albert KOK via Creative CommonsDuring a recent visit to the Georgia Aquarium, a guide was sharing interesting facts about the “Tropical Diver” exhibit.
This species is deemed critically endangered by the IUCN because of its reproductive issues (slow growth, late sexual maturity) and overfishing. Groups like Florida State University’s Coleman & Keening Laboratory are promoting mangrove protection and trying to shift the public’s perception of the Goliath grouper as being nothing more than a big, lazy nuisance.
Gulf grouper are large fish that live in shallow, coastal areas during their first 2 years of their life, before moving on to rocky reefs and kelp beds. Gulf grouper used to be very common in the eastern Pacific Ocean, but they became scarce because commercial and recreational fisherman could easily catch them.
Their abundance has severely declined since the mid-20th century primarily because of direct harvest by commercial and artisanal fisheries. Outside a known population in Bahia Magdalena, there is no published evidence of gulf grouper along the Pacific coast of the Baja California peninsula.
Adult gulf grouper are mainly found around rocky reefs, underwater mountains, and kelp beds. Gulf grouper are also likely protogynous hermaphroditic, which means that they mature as females and later transition into males.
Adult gulf grouper gather in large groups to reproduce once per year. They gather at reefs and underwater mountains and form spawning aggregations from April to June.
Activities that may degrade their habitat include the release of contaminants, such as urban runoff, wastewater, or oil and gas spills. Pollution can also reduce the amount of oxygen in the water or deliver chemicals that are toxic to these fish.
Physical barriers, such as shoreline and offshore development can also threaten gulf grouper by limiting their access to important breeding or feeding areas. Overfishing Direct harvest of gulf grouper, especially at spawning aggregation sites, is the biggest threat to the species.
This means that there are fewer male groupers left in the oceans, which makes reproduction more difficult. It lives in shallow tropical waters at small depths that range from 16 to 164 feet (5 – 50 meters) among coral and artificial reefs.
The Atlantic Goliath grouper can grow until it reaches approximately 8.2 ft (2.5 m) long and it weighs about 790 lb (360 kg). Although the Atlantic Goliath grouper seems to be scary for its large size and even wide mouth, it is not extremely dangerous but it is courageous.
Being fearless and delicious at the same time is not good for this fish as these two factors are the main reasons behind making it highly sought after by fishermen and thus harvesting it in large numbers. Treating this fish in such a cruel way was the main reason behind making it endangered and this is why it was necessary to protect it and entirely ban harvesting it.
The Atlantic Goliath grouper is fearless which means that it is not scared easily and this is why it attacks different creatures in the sea even divers and the 11 feet lemon sharks. The Atlantic Goliath grouper eats most of what it can attack and this includes barracudas, octopus, fish, young sea turtles, crustaceans and even sharks.
The aggregation of large numbers of the fish in a small area during the spawning season attracted commercial and sports fishermen to the species. United States banned the fishing for Goliath groupers in its waters in 1990.
With fishing no longer affecting its numbers, scientists searched for other potential threats to the Goliath grouper. Mosquito control measures and water drainage projects in the Everglades have both impacted heavily on the Florida mangrove swamps.
The loss of the waterways making up part of its nursery will not aid in the recovery of Goliath grouper numbers. A rapid increase in dinoflagellates of the species Karina breves is responsible for the marked color change of the sea.
As well as changing the color of seawater, Karina breves produces a neurotoxin, called breve toxin, which is deadly to many fish. Scientists from National Oceanic and Atmosphere Administration (NOAA) examine these fish to ascertain which species are threatened by red tide events.
Without our help in maintaining its environment the Atlantic Goliath grouper may join the dodo in extinction Which is why there are closed seasons for certain fish, ensuring a time when they can be left alone to breed in peace and to perpetuate their species.
They are mostly found in the Northern Bahamas but only the Nassau grouper is on the IUCN Red List as an Endangered Species in need of protection. Sad to say, mankind is the main cause of the population fragility that has led to the official listing, and the imposition of a strict closed season for 3 months between December 1st and February 28th.
Scientific studies have shown that commercial overfishing has reduced a thriving population to fewer than 10,000 mature fish. An adult can grow to more than a meter long, and weigh 25 kg They tend to be solitary daytime feeders, eating small fish & crustaceans Their large mouths are used to ‘inhale’ or suck in prey The coloring of an individual can vary from red to brown These fish have little black spots around the eyes (I’ve no idea why).
The Nassau grouper (Epimetheus stratus) inhabits the waters of the Bahamas and the Caribbean, and averages about 20 pounds in weight. “The uplifting of the Nassau grouper to Critically Endangered status is a renewed call to action following the implementation of 10 years of regulations through size limits, closed seasons and closed areas in Belize which has yet to provide adequate protection for this beleaguered species,” said Dr. Alexander Too, Senior Conservation Scientist for the Wildlife Conservation Society’s Belize Program.
Heavy fishing conducted during the grouper ’s enormous spawning aggregations, which occur over underwater promontories just after the full moons in December through March, is especially harmful to this species, by removing the biggest and best adults from the population. The new assessment on the Nassau grouper and its new Critically Endangered listing was recently published and supported by studies and data generated by WCS scientists working in the coastal waters of Belize.
Thirteen of Belize’s Nassau grouper aggregation sites are fully protected, and fishing for the species is closed for four months. “Our most recent findings on the Nassau grouper and its decline in key aggregation sites, along with the new designation as a Critically Endangered species, indicate that this fish is in need of a national conservation plan in Belize and in other countries where these groupers exist,” said Nicole Ail Gomez, Director of WCS’s Belize Program.