Epinephelus itajara

Goliath grouper

Photo credit: Leonardo Bueno

IUCN Red List Assessment VULNERABLE (2018)

Range Description: This species is distributed in the Atlantic Ocean in the west from northeastern Florida, south along the U.S., throughout the Gulf of Mexico and Caribbean Sea, and along South America to Santa Catarina, Brazil. In the eastern Atlantic, it occurs along West Africa from Senegal to Cabinda, Angola (for map and countries see IUCN Red List Assessment). Occurs down to about 50 m.

Species Summary: The goliath grouper is widely distributed and inhabits hard reef structure and mangrove areas. Adults are often associated with offshore rocky reefs, occasional coral reefs, wrecks, artificial reefs and oil platforms. While mangroves are the primary juvenile habitat, small fish are also observed on adjacent inshore structured habitats, such as seagrass, tide pools, shallow rocky areas, jetties and docks, returning to ‘home’ sites in nearby mangroves at low tide.

Young Goliath grouper in mangrove, Florida. Photo Credit: Don DeMaria

This species primarily consumes fishes, crabs and crustaceans, generally lower trophic level species. Maximum total length is 250 cm. Species longevity, as determined by otoliths, is at least 37 years and age of first maturity is about 6 years. It is the largest grouper in the western Atlantic, reaching over 2 m in length and nearly 450 kg in weight. Both juveniles and adults have limited home ranges, within which they exhibit some degree of territoriality, displaying to intruders with an open mouth, quivering body and a booming sound generated by muscular contractions of the swim bladder.

Goliath grouper Aggregation, Florida: Photo Credit: Walt Stearns

Adults changing colour in aggregation, Florida. Photo credit: Walt Stearns

The species reproduces in small (fewer than about 150 adults) aggregations at the same locations, including wrecks, each year, generally from August to mid-October (with some temporal variation) in relatively shallow (10-50 m) waters. Adults can migrate up to 500 km to spawning sites as determined from tagging studies.

Tagging large Goliath grouper, Florida. Credit Chris Koenig

Males and females have similar coloration except during the spawning season when males can take on a courting pattern and there are subtle colour changes. Unlike many other groupers, this species appears to be gonochoristic, although its sexual pattern has yet to be studied in detail. During the spawning aggregations, which can be dramatic and are attractive to divers who are willing to pay to visit them, males and females interact and are often readily filmed and photographed.

https://www.youtube.com/watch?v=UgjuNpPAJoA : 1.34 minutes

https://www.youtube.com/watch?v=N4RdsXmfHes : 1.07 minutes

 

Fisheries: The species is substantially reduced from former levels throughout its range, according to available information. This situation is largely attributable to overfishing and loss of nursery habitat. Many fishers have commented that large aggregations and large individuals have disappeared from many sites, leaving only remnants of historical sizes and only local knowledge of what was once present, with photographic and newspaper records providing an important historic perspective. In Florida, overfishing by commercial and recreational fishermen occurred rapidly because the characteristics of these fish–their longevity, aggregating behaviour and sedentary nature, combined with technological advances in positioning gear over the last 30 years–made them particularly vulnerable to fishing pressure. Likewise in South Brazil, historically present aggregations, once with least 60 individuals have dwindled to only a dozen fish, according to local knowledge. In both Belize and Brazil juvenile populations are heavily fished and are undergoing declines, with their important mangrove habitat also declining.

 

Management/Conservation: A fishing moratorium has been in place in U.S. waters for the past 27 years, and the population has been mostly increasing as a result, although it is not yet fully recovered. In Brazil, a fishing ban has been in place since 2002; however, due to lack of enforcement in most areas there is no sign of recovery, while removal and/or degradation of mangroves across its range is a major threat to juvenile survival. In the U.S. other threats include reduced genetic diversity, health stresses caused by high mercury concentrations and localised recruitment failures caused by extreme red tide and cold water events in juvenile habitat. Nonetheless, there are signs of growth in both juvenile and adult populations, following protection, with one aggregation off the southeast Florida coast that existed in the 1960s and disappeared in the 1980s, reappearing in 2005 with about 65 individuals. In spite of a 7-year moratorium on fishing the species in Brazil, there are no clear signs of recovery. The problem is intensified by the pressure exerted on juveniles, known as “meretes”, which fishers do not recognize as having the same protected status as adults.

Photo Credit: Leonardo Bueno

Due to increases in the species, there is pressure in the U.S. from some commercial and recreational fishers to reopen the fishery for the goliath grouper. However, uncertainty regarding population status suggests proceeding in a precautionary manner. On the other hand, there is also an interesting, and much broader, discussion regarding the human relationship with this and similar megafauna, especially threatened species that were once heavily exploited. Interesting discussions on this issue are available in the papers cited by Mazzoldi et al., 2019; Koenig et al., 2019 and Shideler et al., 2016. Also, recent campaigns to raise awareness about the endangered condition and protected status of the species are becoming more prevalent (e.g. www.merosdobrasil.org) and are hoped to have a positive effect.

Key Recent Publications on biology, trade, fisheries and management: for earlier publications, please refer to IUCN Red List Assessment and book on spawning aggregations https://www.springer.com/gp/book/9789400719798

Adams, D.H. and Sonne, C. 2013. Mercury and histopathology of the vulnerable goliath grouper, Epinephelus itajara, in U.S. waters: A multi-tissue approach. Environmental Research 126: 254-263

Artero, C., Murie, D.J., Koenig, C.C., Berzins, R., Bouchon, C. and Lampert, L. 2015b. Age, growth, and mortality of the Atlantic goliath grouper Epinephelus itajara in French Guiana. Endangered Species Research 28(3): 275-287.

Bertoncini, A.A., Aguilar-Perera, A., Barreiros, J., Craig, M.T., Ferreira, B. and Koenig, C. 2018. Epinephelus itajara. The IUCN Red List of Threatened Species 2018: e.T195409A46957794. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T195409A46957794.en

Bueno, L.S., Bertoncini, A.A., Koenig, C.C., Coleman, F.C., Freitas, M.O., Leite, J.R., De Souza, T.F. and Hostim‐Silva, M. 2016. Evidence for spawning aggregations of the endangered Atlantic goliath grouper Epinephelus itajara in southern Brazil. Journal of Fish Biology 89(1): 876-889.

Koenig, C.C. and Coleman, F.C. 2016. Regional age structure, reproductive biology and trophic patterns of adult Goliath Grouper in Florida. NOAA MARFIN Project NA11NMF4330123.

Koenig, C.C., Bueno, L.S., Coleman, F.C., Cusick, J.A., Ellis, R.D., Kingon, K., Locascio, J.V., Malinowski, C., Murie, D.J. and Stallings, C.D. 2016. Diel, lunar, and seasonal spawning patterns of the Atlantic goliath grouper, Epinephelus itajara, off Florida, United States. Bulletin of Marine Science 93(2): 391-406.

Koenig, C. C., Coleman, F. C. and Malinowski, C. R. 2019. Atlantic Goliath Grouper of Florida: To Fish or Not to Fish. Fisheries 13 pp.

file:///C:/Users/Yvonne%20Sadovy/Downloads/GG%20paper%20in%20FISHERIES%20(1).pdf

Mazzoldi C, Bearzi G, Brito C, Carvalho I, Desiderà E, Endrizzi L, et al. 2019. From sea monsters to charismatic megafauna: Changes in perception and use of large marine animals. PLoS ONE 14(12): e0226810. https://doi.org/10.1371/ journal.pone.0226810

Shideler, G., and Pierce, B. 2016. Recreational diver willingness to pay for goliath grouper encounters during the months of their spawning aggregation off eastern Florida, USA. Ocean and Coastal Management 129, 36-43.

Zapelini, C., Giglio, V.J., Carvalho, R.C., Bender, M.G. and Gerhardinger, L.C. 2017. Assessing Fishing Experts’ Knowledge to Improve Conservation Strategies for an Endangered Grouper in the Southwestern Atlantic. Journal of Ethnobiology 37(3): 478-493.