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The Red Grouper, Epinephelus morio. Illustration by Diana Rome Peebles 1998. Courtesy of Florida Fish and Wildlife Conservation Commission, Division of Marine Fisheries.

Species Name: Epinephelus morio Valenciennes, 1828
Common Name: Red Grouper
Synonymy: Serranus morio Valenciennes in Cuvier and Valenciennes, 1828
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Chordata Osteichthyes Perciformes Serranidae Epinephelus

    Other Taxonomic Groupings

    Superclass: Osteichthyes
    Subclass: Neopterygii
    Infraclass: Teleostei
    Superorder: Acanthopterygii

    Species Description

    The red grouper, Epinephelus morio, is a moderately sized, robust grouper that grows to approximately 125 cm (4.1 feet) and may weigh 23 kg (50.7 pounds) or more. Most, however, do not achieve this size. Body depth is less than head length. Eyes are large, and the nostrils are unequal in size, with the posterior pair slightly larger than the anterior pair. The preopercule has somewhat enlarged serrae present on the angle. The opercule has a straight upper edge and 3 flat spines, with the center spine being the most elongate. There are 15-16 gill rakers on the lower limb of gill arch. Scales are small and ctenoid, numbering 60-68 along the lateral line. The dorsal fin has 11 spines, the second of which is the longest. The soft dorsal has 16-17 soft rays. The interspinous membrane is not notched. The anal fin has 3 spines and 8-10 soft rays. The pelvic fins are shorter than the pectoral fins. The bases of soft dorsal and anal fins have scales and thicker skin. The caudal peducle lacks a saddle. The caudal fin is truncate. Body color is highly variable, but typical color is dark red to reddish brown, fading to pink or lighter red on the sides and ventral surface. Whitish spots and blotches are scattered over the body surface, with small black dots around the eyes. The dorsal, anal, and caudal fins all have dark outer margins. When resting, the color pattern may become banded, as occurs in the Nassau grouper, E. striatus (Bohlke and Chaplin 1964; Fischer 1978).

    Potentially Misidentified Species

    The red grouper is distinguished from other members of its genus by the second dorsal spine, which is the longest; and by the interspinous membrane, which is not notched as it is in other Epinephelus species. Further, the pelvic fins in the red grouper are shorter than the pectorals and are inserted posterior to the pectoral fin base. The opposite condition is true for the Warsaw grouper, E. nigritus; the yellowedge grouper, E. flavolimbatus; and the misty grouper, E. mystacinus; all of which have longer pelvic fins than pectoral fins, and have the pelvic fins inserted anterior to the pectoral fin base.

    Red groupers are distinguished from members of the Mycteroperca by having a shorter body, 11 dorsal spines, 9 soft rays on the anal fin, and by thicker skin at the bases of the dorsal and anal fins (Fischer 1978).

  2. HABITAT AND DISTRIBUTION

    Regional Occurrence

    Ephinephelus morio ranges from New England south through Bermuda, Florida, the Gulf of Mexico, the Bahamas and the Caribbean, to southeastern Brazil (Bohlke and Chaplin 1968, Fischer 1978). Occurrences of this species north of the Carolinas are thought to be due to larval transport in the Gulf Stream rather than from immigration of adults (Thompson and Munro 1978).

    Primarily a continental species, E. morio has the widest distribution of all western Atlantic groupers (Roe 1976). Its center of abundance extends from the Florida shelf into the eastern Gulf of Mexico (Moe 1969). It becomes more rare in the West Indies (Randall 1968).

    IRL Distribution

    While juveniles are common inhabitants of seagrasses and shallow reef areas in south Florida, they occur less often inside the IRL. Fish less than 6 years old can be found in nearshore reefs. Adults occur in offshore hardbottom habitats, where they are harvested commercially and recreationally.

  3. LIFE HISTORY AND POPULATION BIOLOGY

    Age, Size, Lifespan

    Red grouper grow to 125 cm (4.1 feet) total length (TL) and may weigh 23 kg (50.7 pounds), though most are harvested at 70 - 72 cm (27.5 - 28.3 inches) TL (Jory and Iversen 1989). Males and females grow at approximately similar rates, though males tend to reach larger adult size (Jory and Iversen 1989). They may live 30 years or more (Moe 1969; Beaumariage and Bullock 1976).

    Moe reported that red grouper grow at a rate of 5.8 - 10.3 mm (0.22 - 0.40 inches) per month.

    Abundance

    Epinephelus morio is more abundant in the eastern Gulf of Mexico and in south Florida than it is in east central Florida.

    Reproduction

    Red grouper, like most serranid fishes, are protogynous hermaphrodites, beginning life as females, with some later transforming into males. Females mature at approximately 35 - 50 cm Standard length (SL), at about 4-6 years of age (Heemstra and Randall 1993), but reach their greatest reproductive potential when they are 8-12 years of age.

    Females transform to males between ages 7-14, at a rate of approximately 15% per year. Transition to male can occur when females reach 27 cm (10.6 inches) SL, but most commonly occurs after females grow to 50 cm (19.7 inches) SL (Jory and Iversen 1989). Males comprise approximately 10% of all year classes until approximately age 9 when males reach 50 cm (19.7 inches) SL. Sex ratios are not equal until approximately age 15, when most red groupers have reached 63 cm (24.8 inches) SL (Moe 1969; Beaumariage and Bullock 1976; Jory and Iversen 1989).

    In the eastern Gulf of Mexico, spawning occurs from January through June, peaking in March and May in waters 19 - 21°C, and 20-90 m deep (Roe 1969; Johnson et al. 1998). Females with oocytes in varying stages of development are collected throughout the spawning season, suggesting that red grouper are likely to be batch spawners.

    Female fecundity ranges from 312,000 - 5.7 million eggs per female, depending on size (Moe 1969).

    Embryology

    Ephinephelus morio eggs are pelagic, measuring less than 1mm in diameter and having a single oil globule. Larval red grouper leave the plankton after approximately 1 month and metamorphose to benthic juveniles when they reach approximately 20-25 mm SL (Beaumariage and Bullock 1976).

  4. PHYSICAL TOLERANCES

    Temperature

    Roe (1976) reported red grouper to a depth of 189 m, where bottom temperatures ranged from 15 - 30°C.

    Other Physical Tolerances

    Stout (1980) reported that red grouper in the southeastern United States had an average of 0.0008 ppm DDT, and undetectable levels of PCB's compared to other fishes.

  5. COMMUNITY ECOLOGY

    Trophic Mode

    All groupers are unspecialized and opportunistic in their feeding habits. Red grouper are among the top predators in reef community food webs and may control some aspects of community balance in reef systems (May et al. 1979). The diet is varied but commonly includes lutjanid and sparid fishes, as well as many types of invertebrates including xanthid and portunid crabs, spiny lobster, snapping shrimp, stomatopods, octopus, and squid and penaeid shrimp, especially the pink shrimp (Penaeus duorarum) (Longley and Hildebrand 1941; Moe 1969; Costello and Allen 1970).

    Red grouper are highly susceptible to the effects of red tide organisms, and were extirpated from reefs 12-15 m off Sarasota, Florida in 1991 as the result of red tide poisoning (Heemstra and Randall 1993).

    Competitors

    Groupers likely compete interspecifically due to overlapping food habits, space and habitat requirements (Thompson and Munro 1978). Groupers are also likely to compete for prey with other large species such as jacks, snappers, barracuda, and sharks.

    Predators

    Predators of smaller groupers include other groupers and moray eels Larger groupers are likely preyed upon by sharks, among them the sandbar shark, Carcharhinus plumbeus; and the great hammerhead, Sphryna mokarran (Compagno 1984).

    Parasites

    Groupers suffer from a number of parasites including digenetic trematodes, cestodes, and nematodes (Manter 1947; Overstreet 1968; Fajer et al. 1979). Trematodes parasites include Helicometra, Lepidapedon, and Stephanostomum species. Other parasites that infect red grouper include the cestode Callotetrarhynchus sp., and nematodes such as Anasakis sp. (Manter 1947).

    Habitats

    Epinephelus morio is a reef-associated, non migratory species that occurs in low numbers and can be found in depths of 5 - 300m (Jory and Iversen 1989; Heemstra and Randall 1993). Young juveniles are commonly encountered in seagrass beds less than 15m deep (Smith 1971) in south Florida. Older juveniles occupy shallower water in hard bottom and reef habitats approximately 36 m deep. Immature fishes 1 - 6 years old and measuring less than 50 cm SL utilize nearshore reefs (Beaumariage and Bullock 1976). Adults occur primarily over rocky and muddy bottoms (Fischer 1978), on limestone ledges, wrecks, and caves, but are relatively uncommon on coral reefs. Moe (1969) reported that red grouper in the eastern Gulf of Mexico typically rest on the benthos, concealed in rocks, crevasses, or caverns, and are found from 3 - 122 m deep.

    Moe (1969) summarized movements of red groupers as they age: Early years are lived in shallow estuarine or nearshore waters 3-18m deep. After reaching 400-450 mm SL at 4-6 years of age, they leave nearshore reefs and move to waters deeper than 36 m. This migration apparently coincides with onset of sexual maturity.

  6. ADDITIONAL INFORMATION

    Fisheries Importance

    Commercial Fishery: The red grouper is both commercially and recreationally important throughout its range, and is one of the most abundant grouper species in southern Florida. Boats must be used by recreational anglers seeking red grouper, as they are rarely caught from beaches and docks (Jory and Iversen 1989).

    Approximately 99% of the Florida harvest of red grouper is taken in the eastern Gulf of Mexico on Florida's west coast. Between 1987 - 2001, the commercial harvest of red grouper in Florida totaled 95.3 million pounds, and was valued at $164.8 million. Of this, just 628,465 pounds of red grouper, valued at $1.2 million was harvested on Florida's east coast during this time period. Within the 5 county area encompassing the IRL (Volusia, Brevard, Indian River, St. Lucie and Martin Counties) 257,339 pounds of red grouper, 41% of the east coast total, was commercially harvested This catch was valued at approximately $465,435, and ranks the red grouper forty-eighth in commercial value, and sixtieth in pounds harvested.

    Figure 1 below shows the dollar value of the red grouper fishery to IRL counties by year. The commercial red grouper fishery ranged in value from a high of $60,458 in 1995 to a low of $3,622 in 1990. Volusia county accounted for 59% of the catch, followed by Brevard (18%), St. Lucie (10%), Martin (8%) and Indian River (5%) Counties.


    Figure 1. Annual dollar value of the commercial catch of red grouper to the 5-county area of the Indian River Lagoon.


    Figure 2. Total red grouper dollar value and percentage by county for the years 1987 - 2001.


    VOLUSIA BREVARD INDIAN RIVER ST. LUCIE MARTIN TOTAL
    Year Value Value Value Value Value Value IRL
    1987 $203 $1,940 $363 $2,402 $8,800 $13,708
    1988 $706 $11,585 $574 $14,006 $11,019 $37,890
    1989 $347 $2,436 $103 $4,216 $1,740 $8,842
    1990 $511 $806 $529 $1,313 $463 $3,622
    1991 $542 $1,030 $1,166 $7,395 $12,232 $22,365
    1992 $761 $4,039 $751 $5,134 $27,029 $37,714
    1993 $953 $2,183 $1,337 $3,606 $26,163 $34,242
    1994 $757 $3,330 $1,719 $3,068 $30,600 $39,474
    1995 $3,037 $3,958 $2,947 $6,000 $44,516 $60,458
    1996 $2,495 $2,721 $1,907 $2,832 $18,244 $28,199
    1997 $2,485 $3,754 $2,441 $9,792 $17,327 $35,799
    1998 $6,369 $2,917 $4,692 $6,429 $31,802 $52,209
    1999 $11,866 $737 $3,534 $8,315 $12,671 $37,123
    2000 $5,156 $2,187 $1,843 $4,725 $21,762 $35,673
    2001 $1,376 $1,838 $1,138 $5,012 $8,753 $18,117
    Cumulative Totals: $37,564 $45,461 $25,044 $84,245 $273,121 $465,435
    Table 1. Total dollar value of IRL red grouper, Epinephelus morio, between 1987 - 2001.


    VOLUSIA BREVARD INDIAN RIVER ST. LUCIE MARTIN
    Year % Total % Total % Total % Total % Total
    1987 1.48% 14.15% 2.65% 17.52% 64.20%
    1988 1.86% 30.58% 1.51% 36.96% 29.08%
    1989 3.92% 27.55% 1.16% 47.68% 19.68%
    1990 14.11% 22.25% 14.61% 36.25% 12.78%
    1991 2.42% 4.61% 5.21% 33.07% 54.69%
    1992 2.02% 10.71% 1.99% 13.61% 71.67%
    1993 2.78% 6.38% 3.90% 10.53% 76.41%
    1994 1.92% 8.44% 4.35% 7.77% 77.52%
    1995 5.02% 6.55% 4.87% 9.92% 73.63%
    1996 8.85% 9.65% 6.76% 10.04% 64.70%
    1997 6.94% 10.49% 6.82% 27.35% 48.40%
    1998 12.20% 5.59% 8.99% 12.31% 60.91%
    1999 31.96% 1.99% 9.52% 22.40% 34.13%
    2000 14.45% 6.13% 5.17% 13.25% 61.00%
    2001 7.60% 10.15% 6.28% 27.66% 48.31%
    Table 2. By-county annual and cumulative percentages of the red grouper harvest for the years 1987-2001.


      Volusia Brevard Indian River St. Lucie Martin
    Dollars $273,121 $84,245 $25,044 $45,461 $37,564
    % 58.7% 18.1% 5.4% 9.8% 8.1%
    Table 3. By-county cumulative dollar value and percentage of total for the red grouper harvest from 1987 - 2001.

    Recreational Fishery

    Within the 5-county area of the Indian River Lagoon, recreational anglers captured 96,813 red grouper (Table 4). Figure 3 below shows the annual recreational landings of red grouper between 1997 - 2004. The bulk of the recreational catch (65.3%) is taken in waters 3 - 200 miles offshore. Approximately 27.8% of the recreational catch is harvested from the shoreline to 3 miles offshore. Anglers fishing inland waters other than the Indian River Lagoon accounted for 4.0% of the harvest, while those fishing within the confines of the IRL accounted for only 2.9% of the total.



    Figure 3. Survey data for the common snook recreational fishery showing the number of fishes harvested in East Florida waters from 1997 - 2004.


    Figure 4. Summary of the common snook recreational harvest and percentage of total by area from 1997 - 2004.


    To 3 Miles To 200 Miles Other Inland IRL TOTAL
    1997 2,296 10,439 1,156   13,891
    1998 1,898 15,960 540   18,398
    1999 3,517 5,082 772 266 9,637
    2000 3,773 6,822   888 11,482
    2001 4,341 5,398     9,739
    2002 3,710 7,968 292 625 12,595
    2003 1,674 6,791 1,065 1,052 10,582
    2004 5,684 4,805     10,489
    Total: 26,893 63,265 3,825 2,831 96,813
    Table 4. Summary data for the red grouper, Epinephalus morio, recreational fishery in Eastern Florida waters from 1997 - 2004. Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.


    To 3 Miles To 200 Miles Other E. FL Inland IRL
    % Total % Total % Total % Total
    1997 16.5% 75.1% 8.3% 0.0%
    1998 10.3% 86.7% 2.9% 0.0%
    1999 36.5% 52.7% 8.0% 2.8%
    2000 32.9% 59.4% 0.0% 7.7%
    2001 44.6% 55.4% 0.0% 0.0%
    2002 29.5% 63.3% 2.3% 5.0%
    2003 15.8% 64.2% 10.1% 9.9%
    2004 54.2% 45.8% 0.0% 0.0%
    Table 5. By-county annual and cumulative percentages of the red grouper harvest for the years 1997 - 2001. Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.


    To 3 Miles To 200 Miles Other Inland IRL
    No. Fish 26,893 63,265 3,825 2,831
    % 27.78% 65.35% 3.95% 2.92%
    Table 6. Summary of the red grouper recreational harvest and percentage of total fish captured in each area from 1997 - 2004. Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.
  7. REFERENCES

    Beaumariage, D.S., and L.H. Bullock. 1976. Biological research on snappers and groupers as related to fishery management requirements. Pages 86-94 in H.R. Bullis and A.C. Jones, eds. Proceedings: colloquium on snapper-grouper fishery resources of the western central Atlantic Ocean. Fla. Sea Grant Rep. 17.

    Bohlke, J.E., and C.C.G. Chaplin. 1968. Fishes of the Bahamas and adjacent waters. Livingston Publishing Company, Wynnewood, Pennsylvania. 771 p.

    Brulé, T. and L.G. Rodriguez Canche, 1993 Food habits of juvenile red groupers,Epinephelus morio (Valenciennes, 1828), from Campeche Bank, Yucatan, Mexico. Bull. Mar. Sci. 52(2):772-779.

    Brule, T., D, Ordaz Avila, M. Sanchez Crespo, and C. Deniel. 1994. Seasonal and diel changes in diet composition of juvenile red grouper (Epinephelus morio) from Campeche Bank. Bull. Mar. Sci. 55:255-262.

    Brule, T., C. Deniel, M.T. Colas and C.M. Sanchez, 1999 Red grouper in the southern Gulf of Mexico. Trans. Amer. Fish. Soc. 128(3):385-402.

    Brulé, T., C. Déniel, T. Colás-Merrufo and M. Sánchez-Crespo, 1999 Red grouper reproduction in southern Gulf of Mexico. Trans. Am. Fish. Soc. 128(3):385-402.

    Compagno, L.V.J. 1984. FAO species catalogue. Vol. 4: Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2:Carcharhiniformes. FAO Fish. Synop. (125) Vol. 4, Pt.2: 251-655.

    Costello, T.J., and D.M. Allen. 1970. Synopsis of biological data on the pink shrimp, Penaeus duorarum duorarum Burkenroad, 1939. FAO Fish. Rep.57-4:1499-1537.

    Fischer, W., ed. 1978. FAO species identification sheets for fishery purposes.Western central Atlantic (fishing area 31). Vol. IV. Rome, FAO.

    Heemstra, P.C. and J.E. Randall, 1993. FAO species catalogue. Vol. 16. Groupers of the world (family Serranidae, subfamily Epinephelinae). An annotated and illustrated catalogue of the grouper, rockcod, hind, coral grouper and lyretail species known to date.. FAO Fish. Synop. 125(16):382 p.

    International Game Fish Association, 1991 World record game fishes. International Game Fish Association, Florida, USA.

    Johnson, A.K., P. Thomas, and R.R. Wilson. 1998. Seasonal cycles of gonadal development and plasma sex steroid levels in Epinephelus morio, a protogynous grouper in the eastern Gulf of Mexico. Journal of Fish Biology 52:502-518.

    Johnson, A.G. and L.A. Collins, 1994 Age-size structure of red grouper, (Epinephelus morio), from the eastern Gulf of Mexico. N.E. Gulf Sci. 13(2):101-106.

    Johnson, G.D., and P. Keener. 1984. Aid to identification of grouper larvae. Bull. Mar. Sci. 34(1):106-134.

    Jory, D.E., and E.S. Iversen. 1989. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (south Florida) -black, red, and Nassau groupers. U.S. Fish Wildl. Serv. Biol. Rep. 82(11.110). U.S. Army Corps of Engineers, TR EL-82-4. 21 pp.

    Longley, W.H., and S.F. Hildebrand. 1941. Systematic catalogue of the fishes of Tortugas, Florida, with observations on colour, habits and local distributions. Carnegie Inst. Wash. Pap. Tortugas Lab. 34. 331 pp.

    Overstreet, R.M. 1968. Digenetic trematodes of marine teleost fishes from Biscayne Bay, Florida. Unpubl. Ph.D. Dissertation. University of Miami, CoralGables, Fla. 188 pp.

    Manooch, C.S., 1987 Age and growth of snappers and groupers. p. 329-373. In J.J. Polovina and S. Ralston (eds.) Tropical snappers and groupers: biology and fisheries management. Ocean Resour. Mar. Policy Ser. Westview Press, Inc., Boulder and London.

    Manter, H.W. 1947. The digenetic trematodes of marine fishes of Tortugas, Florida. Am. Midl. Nat. 38(2): 257-416.

    Manter, H.W. 1947. The digenetic trematodes of marine fishes of Tortugas, Florida. Am. Midl. Nat. 38(2): 257-416.

    May, R.M., J.R. Beddington, C.W. Clark, S.J. Holt, and R.M. Laws. 1979. Management of multispecies fisheries. Science 205:267-277.

    Moe, M.A., Jr. 1969. Biology of the red grouper (Epinephelus morio Valenciennes) from the eastern Gulf of Mexico. Prof. Pap. Ser. Mar. Lab. Fla. No. 10. 95 pp.

    Randall, J.E. 1967. Food habits of reef fishes of the West Indies. Stud. Trop. Oceanogr. Univ. Miami 5:665-847.

    Randall, J.E. 1968. Caribbean reef fishes. TFH Publications, Jersey City, New Jersey. 18 pp.

    Rivas, L.R. 1964. Western Atlantic serranid fishes (groupers) of the genus Epinephelus. Q. J. Fla. Acad. Sci. 27(1):17-30.

    Roe, R.B. 1976. Distributions of snappers and groupers in the Gulf of Mexico as determined from exploratory fishing data. Pages 129-164 in: H. R. Bullis and A.C. Jones, eds. Proceedings: colloquium snapper-grouper fishery resources of the western central Atlantic Ocean. Fla. Sea Grant Rep. 17.

    Smith, C.L. 1961. Synopsis of biological data on groupers (Epinephelus and alliedgenera) of the western North Atlantic. FAO Fish. Biol. Synop. No. 23. 61 pp.

    Stiles, T.C. and M.L. Burton, 2000 Age, growth and mortality of red grouper, Epinephelus morio, from the southeastern United States. p. 123-137. In: Proceedings of the 43rd Gulf and Caribbean Fisheries Institute.

    Stout, V.F. 1980. Organo-chlorine residues in fishes from the northeast Atlantic  Ocean and Gulf of Mexico. U.S. Natl. Mar. Fish. Serv. Fish. Bull. 78:51-58.

    Thompson, R., and J.L. Munro. 1978. Aspects of the biology and ecology of Caribbean reef fishes: Serranidae (hinds and groupers). J. Fish Biol. 12:115-146.

    Thompson, R. and J.L. Munro, 1983 The biology, ecology and bionomics of the hinds and groupers, Serranidae. p. 59-81. In: J.L. Munro (ed.) Caribbean coral reef fishery resources. ICLARM Stud. Rev. 7.

Report by: K. Hill, Smithsonian Marine Station
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Page last updated: July 15, 2005

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