Grouper Ecology

Daniel Brown
• Saturday, 14 November, 2020
• 14 min read

Common Name grouper Kingdom Animalia Phylum Chordata Class Osteichthyes Order Performed Family Serranidae Genus Species Epimetheus SPP. Diet Other fishes, squids, and crustaceans Incubation Oviparous (egg laying) Sexual Maturity No data Life Span Relatively long-lived; some groupers have lived at SeaWorld, San Diego for more than 30 years Range Varies by species Habitat Varies by species Population GLOBAL No data Status IUCN: Several species listed as Vulnerable or Threatened CITES: Not listed Uses: Not listed Some fish in this family can grow to incredible sizes, such as the Jewish (Epimetheus Tamara) of the tropical Atlantic Ocean and the Queensland grouper (E. lanceolatus) of Australia.

epinephelus lanceolatus giant grouper brindle bass gill ecology
(Source: www.dreamstime.com)


Some groupers are so huge that when they open their mouths to feed, they create a suction that is powerful enough to inhale small prey. In addition to their possible great size, another defense that some groupers have is the ability to change the color of their skin.

The Caribbean Coney (Cephalopods vulva) demonstrates a more advanced color shift. If disturbed, the Caribbean Coney will try to hide in a coral crevice, which normally has a white, sandy bottom.

To blend in with this environment, this fish alters its color so that its lower body fades to white and its spots contract to tiny pinpoints. Other groupers have developed color patterns composed of stripes, spots, or blotches that help them to blend in with the bottom of coral reef areas.

All young yellow mouth groupers (Mycteroperca interstitial is) are born females, but as they grow larger they change into males. Only small percentages survive long enough to become a male, thus ensuring the greater majority are egg-laying females.

Even more surprising, some in the genus Serra nus are rare examples of fishes that can be male and female at the same time. In the United States, Jewish and Nassau groupers (E. stratus) are protected from all harvesting.

grouper ecology
(Source: marinelab.fsu.edu)

Bag limits and size restrictions have been placed on other grouper species in the United States as well. These large fish are associated with hard structure such as reefs (both natural and artificial), rocks, and ledges.

It was easy for commercial and recreational fisherman to catch Nassau grouper and it soon became scarce. Because their range exceeds national borders, the best approach to their conservation is regional closed seasons.

Sampling of fish landed in the U.S. Virgin Islands and Puerto Rico during the 1970s and 1980s indicates that Nassau grouper were commonly caught, mostly from spawning aggregation sites. Currently, Nassau grouper are occasionally reported during underwater reef surveys at low density.

Coloration varies, but adult fish are generally light beige, with five dark brown vertical bars, a large black saddle blotch on top of the base of the tail, and a row of black spots below and behind each eye. They can be distinguished from other groupers by the vertical bars and dark saddle coloring along the dorsal part of the area preceding the tail.

Color pattern can change within minutes from almost white too bicolored to uniformly dark brown, according to the behavioral state of the fish. They take advantage of lower light levels at dawn and dusk, combined with the higher number of prey during changeover between diurnal and nocturnal fishes.

grouper goliath ecology
(Source: marinelab.fsu.edu)

Nassau grouper are found in tropical and subtropical waters of the western North Atlantic. This includes Bermuda, Florida, Bahamas, the Yucatán Peninsula, and throughout the Caribbean to southern Brazil.

There has been one verified report of Nassau grouper in the Gulf of Mexico at Flower Gardens Bank. The Nassau grouper is considered a reef fish, but it transitions as it grows through a series of shifts in both habitat and diet.

As juveniles, they are found in nearshore shallow waters in macro algal and seagrass habitats. The main influences on where they live are not known, though water clarity, habitat, and bent hos (the community of organisms in the seabed) seem to be important.

Nassau grouper tend to spend a lot of time in one spot, often on a high-relief coral reefs or rocks in clear water. Larger fish tend to occupy deeper reef areas with greater vertical relief.

Nassau grouper pass through a juvenile bisexual phase, then mature directly as males or females. While adult Nassau groupers can change sex after hormone injection, natural sex-change has not been confirmed.

groupers grouper reef overfishing oceans
(Source: www.livingoceansfoundation.org)

After 1 to 2 months of floating with the ocean currents, the larvae settle in nearshore shallow waters in macro algal and seagrass habitats. Adults are relatively solitary, living in areas that (patchily) overlap other groupers’ home ranges.

In some countries with protective regulations, there are too few enforcement officers to cover a large geographic area with many landing locations. Meanwhile, fish caught during closed season are held and later marketed as legal capture.

The scientific evidence points to this being a bad idea, based on our own research over the last 20 plus years of studying this species and on our review of the literature and reports of colleagues and other scientists throughout the world. The science-free perceptions and very vocal pronouncements of various groups about the biology, behavior, and population status of this species, while loud and strong, should not trump the best available scientific evidence in making management decisions.

Our objective in this brief document is to juxtapose the scientific evidence following from this body of research with the most pervasive opinions voiced in the southeastern United States. The Science: There are two lines of evidence against this view provided by dietary and trophic studies of Goliath Grouper and video graphic surveys of the distribution and abundance of reef fish on reefs off southwest Florida, the center of Goliath Grouper abundance.

Stomach contents represent prey eaten just prior to capture, or a short-term view of diet (Figures 3 and 7). However, for an understanding of diet over the long term, and Goliath Grouper's position in the food web (i.e., trophic level) we used stable isotope analysis (Koenig and Coleman 2009).

grouper coral preview
(Source: www.dreamstime.com)

Results showed a relatively low position in the food web, similar to that of South Florida pinkish (Lagoon rhomboids ; Chaser et al. 2005). The Science: Our stomach content data, sampled from Goliath grouper in areas of high lobster abundance, provide strong evidence against this view.

In this report, Randall indicated that a high percentage of the Goliath grouper diet consisted of spiny lobsters. At that time (1959 – 1961) and in that place (St. John, VI), lobsters were abundant (Randall, personal communication), so the observation of Goliath grouper feeding on them is not surprising.

The Opinion: Goliath grouper, because of their large size, require huge amounts of food to survive and eat indiscriminately, reducing biodiversity on reefs. Their method of predation is to sit and wait for prey, and then use a suction method, common to all groupers and many other reef fish, to draw prey into their mouths. To estimate the food consumption rate of Goliath grouper, we developed a energetics model.

Indeed, this is a world-wide phenomenon that is related to the combined effects of overfishing, coastal development, pollution, and climate change, not to the presence of Goliath grouper. Altered ecological balance will not be regained by reducing the abundance of Goliath grouper, a native species that is recovering from intense overfishing, but by allowing other overfished species to recover while attempting to reduce a variety of human-induced impacts.

Scientists call this phenomenon “shifting baselines” because the perception of “normal” changes with each successive generation. The Science: Our observations suggest that the frequency of Goliath Grouper bites is vanishing small (Figure 7).

grouper ecology
(Source: marinelab.fsu.edu)

We have interacted directly with over 5000 adult Goliath grouper in the water, and have tagged over 2100 large individuals with spear guns. During all these interactions, we have experienced only a single harmless nip on the hand by one individual that we cornered under a ledge in an attempt to make it produce sounds (booms) that we could record.

The Opinion: There must be a periodic kill of hundreds of adult Goliath grouper to obtain data on size, age, and reproductive condition necessary for stock assessment. We have received considerable support from recreational and commercial fishermen interested in participating in non-consumptive research projects that involve use of non-destructive sampling of Goliath grouper.

While the Goliath grouper population is in recovery, the current status is unknown, as is the potential impact of removals of hundreds of adult fish. Certainly the opportunity to educate fishermen in general marine ecology and Goliath grouper biology and conservation practices should far outweigh the completely unnecessary destruction of individuals.

Discussion Goliath grouper is a native species that evolved on reefs on both sides of the Atlantic over millions of years. Part of the problem is the absence of checks and balances on lionfish population expansion through control by predators or other factors.

All the scientists who have studied the behavior and ecology of Goliath Grouper acknowledge their optimism over the ongoing recovery of this species in Florida. For example, the Giant Sea Bass (Stereotypes gigs) population of the Eastern Pacific has not recovered despite nearly 30 years of limited protection.

grouper ecology habitat research
(Source: robertdodgeellis.com)

Optimism is also dampened by the fact that the south Florida ecosystem has been altered to such a high degree over the last 100 years (Ogden et al. 2005), that suitable mangrove nursery in all probability presents a bottleneck to the production of this species (Koenig et al. 2007). Also, losses due to release mortality and illegal harvest result in continued overfishing (Porch et al. 2006).

Because of these issues and the inherent vulnerability of Goliath grouper to fishing pressure, caution should be the hallmark of any management decision. The fact that a number of very vocal people consider Goliath grouper a nuisance species speaks worlds about the poor job we have done collectively as scientists and managers to educate the public about marine systems.

The fact that managers would seriously consider destructive sampling of a species known to be critically endangered elsewhere in their range suggests adherence to political rather than ecological or conservation principles. The benefits of recovery may well extend into commercial enterprises such as ecotourism as more businesses provide opportunities to view these magnificent fish in their natural habitat.

The Goliath grouper (Epimetheus Tamara)is a large, dominant, and increasingly pervasive marine predator inhabiting natural and artificial reef systems throughout Florida. Through a highly coordinated and collaborative effort with a variety of academic and industry partners (Mote Marine Lab, EPS Corporation, NSW) we are conducting controlled experimental studies to quantify Goliath grouper sound production and kinematics in order to understand behavioral responses of fish to non-native objects in their environment.

Scientific classification Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Performed Family: Serranidae Subfamily: Epinephrine Genus: Epimetheus Species: Binomial name Epimetheus summary Synonyms Percy summary Formal, 1775 Serra nus leucostigma Valentines, 1828 Se bastes Milagros Peters, 1864 Epimetheus summary has a standard length which is 2.7 to 3.1 times its depth.

grouper nassau park mangrove everywhere there reef cays habitats migrate shallow pelican creeks individuals deeper patch mature then
(Source: appliedecology.cals.ncsu.edu)

It has a flat or slightly concave region between the eyes. The properly is has slightly enlarged serrations at its corner and the gill cover has a highly convex upper margin.

The membranes between the dorsal fin spines are notched. The overall color is dark olive-brown to dark brownish gray with large pale blotches, the majority being greater than the eyes, and abundant small white spots which lie over this pattern.

This species attains a maximum standard length of 52 centimeters (20 in) Epimetheus summary is a reef-associated species that occurs in shallow protected coral reefs and in shallow lagoons and seaward reef slopes (1 to 30 m) or brackish-water environments.

No published information on the biology of this species has been found. Epimetheus summary is caught by small, local fisheries and has been recorded in fish markets in Egypt and Sudan.

Groupers of the world (family Serranidae, subfamily Epinephrine). An annotated and illustrated catalog of the grouper, rock cod, hind, coral grouper and lyre tail species known to date (PDF).

juvenile grouper barramundi indonesia ecosystem
(Source: www.dreamstime.com)

Media related to Epimetheus summary at Wikimedia Commons Its range includes the Gulf of Mexico and Florida Keys in the United States, the Bahamas, most of the Caribbean, and most of the Brazilian coast.

Scientists from our Southeast Fisheries Science Center are working to understand the changes that have occurred in coral reef ecosystems following the loss of top predators, such as groupers. 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.

grouper preview
(Source: www.dreamstime.com)

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. This project would not have been possible without ongoing collaboration with researchers from Florida State University, Everglades National Park, and the recreational fishing and SCUBA diving communities.

Scientific classification Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Performed Family: Serranidae Subfamily: Epinephrine Genus: Epimetheus Species: Binomial name Epimetheus lanceolatus Synonyms Holocentrus lanceolatus Bloch, 1790 Promiscuous lanceolatus (Bloch, 1790) Serra nus lanceolatus (Bloch, 1790) Serra nus geographic us Valentines, 1828 Serra nus abdominal is Peters, 1855 Barracks gigs Gunther, 1869 Rigorous Goliath DE Vi's, 1882 Serra nus phaeostigmaeus Fowler, 1907 Stereolepoides Thompson Fowler, 1923 The giant grouper has a robust body which has a standard length equivalent to 2.4 to 3.4 times its depth.

The dorsal profile of the head and the intraorbital area are convex, The properly has a rounded corner and a finely serrated margin. The gill cover has a convex upper margin.

goliath groupers grouper florida endangered critically protect mag killing roy ray mission
(Source: www.xray-mag.com)

The adults are greyish-brown in color overlain with a mottled pattern and with darker fins. The giant grouper can grow to huge size with the maximum recorded standard length being 270 centimeters (110 in), although they are more common around 180 centimeters (71 in).

And a maximum published weight of 400 kilograms (880 lb). The giant grouper is a species of shallow water and can be found at depths of 1 to 100 meters (3.3 to 328.1 ft).

Large specimens have been caught from shore and in harbors. They are found in caves and in wrecks while the secretive juveniles occur in reefs and are infrequently observed.

The adults are mainly solitary and hold territories on the outer reef and in lagoons. They have also been caught in turbid water over silt or mud sea beds by prawn fishermen.

The giant grouper is an opportunistic ambush predator which feeds on a variety of fishes, as well as small sharks, juvenile sea turtles, crustaceans and mollusks which are all swallowed whole. Fish which inhabit coral reefs and rocky areas favor spiny lobsters as prey and 177 centimeters (70 in) specimen taken of Maui in Hawaii had a stomach contents of two spiny lobsters and a number of crabs.

grouper lapu fish csudh chemistry edu reef ecology coral culture agri channel business mycteroperca bonaci yellowmouth found
(Source: www.studyblue.com)

Fish living in estuaries environments in South Africa were found to be feeding almost exclusively on the crab Scylla errata. They are, however, curious and frequently approach divers closely.

They are not generally considered dangerous to humans but divers are advised to treat large specimens with caution and not to hand feed them. They are aggregate broadcast spawners, usually with several females per male.

Studies in captive populations suggest that the dominant male and female begin the spawning event as nearly the only spawners for the first day or two, but other members of the aggregation fertilize more eggs as the event progresses, with even the most recently turned males fathering offspring. Giant groupers are diabetic protogynous hermaphrodites, meaning that although some males develop from reproductively functional females other males start to produce sperm without ever having gone through a phase as a reproductive female.

The giant grouper is a highly valued food fish and is taken by both commercial and recreational fisheries. As well as the consumption of its flesh its skin, gall bladder and stomach are used in Traditional Chinese Medicine.

It is valued in Hong Kong as a live fish for the live reef food fish trade, especially smaller specimens. This species is cultured in agriculture and this practice is widespread but there is a restricted supply of juveniles, although hatcheries in Taiwan have produced captive bred juveniles, exporting some for to be grown on in other parts of South-East Asia.

(Source: ucme.wordpress.com)

Many of the fish produced in aquaculture are hybrids between this species and E. fuscoguttatus. IUCN Red List of Threatened Species.

“A study into parental assignment of the communal spawning protogynous hermaphrodite, giant grouper (Epimetheus lanceolatus)”. ^ Peter Palma; Akihito Nakamura; Garden XYZ Libunaoa; et al. (2019).

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1 myfwc.com - https://myfwc.com/fishing/saltwater/recreational/goliath/
2 www.boatus.com - https://www.boatus.com/expert-advice/expert-advice-archive/2020/april/fishing-for-goliath-groupers
3 goliathfishing.com - http://goliathfishing.com/
4 www.fisheyesportfishing.com - https://www.fisheyesportfishing.com/goliath-grouper-fishing/
5 my724outdoors.com - https://my724outdoors.com/blog/2020/02/14/big-goliath-grouper-fishing/
6 ultimatefishingsite.net - http://ultimatefishingsite.net/grouper-fishing/types-of-grouper/