click for previous page Groupers of the World 1 1. INTRODUCTION he serranid Subfamily Epinephelinae com- estuaries or on rocky reefs. Groupers are generally Tprises about 159 species of marine fishes in 15 associated with hard (rocky) bottoms, although ju- genera (Fig. 1), commonly known as groupers, veniles are found in seagrass beds, and adults of a rockcods, hinds, and seabasses. These species are few species prefer sandy or silty areas. Some spe- of considerable economic value, especially in the cies occur in depths of 100 to 200 m (occasionally coastal fisheries of tropical and subtropical areas. It to 500 m); however, the majority inhabit depths less has been estimated that 90% of the world’s harvest than 100 m, and juveniles are often found in tide- of marine food is derived from artisanal fisheries, pools. and groupers are a major component of the arti- sanal fisheries resource. Although groupers are As the major predators of the coral-reef ecosys- usually the most expensive fishes in local markets, tem, most groupers feed on a variety of fishes, separate catch statistics are not reported for most larger crustaceans, and cephalopods . A few grou- species, and landings are often summarized as pers (e.g., Paranthias spp., Epinephelus undulosus) “serranids” or “groupers.” This lack of species-spe- have long, numerous gill rakers and are thus cific catch data is due, in part, to the difficulty of adapted for plankton feeding. Adults of many spe- identifying many of the species. For example, two cies (e.g., Plectropomus spp., Variola louti) are of the most important commercial species, primarily piscivorous, and they are usually seen “Epinephelus guaza” (of the Mediterranean and At- cruising the reef or shallows in search of their prey. lantic Ocean) and E. tauvina (of the Indo-Pacific Most groupers are ambush predators, hiding region) are often misidentified. The importance of amongst the coral and rocks until an unwary fish or crustacean goes by, then catching their prey with a correct species identification should be obvious to every biologist and is certainly appreciated by intel- quick rush and snap of their jaws. The large head ligent farmers and taxonomists. It is essential for the and mouth of the typical grouper enables it to suck proper management of a fishery resource to cor- in a large volume of water (and the prey) in less than rectly identify the species concerned. a second. The numerous inwardly-depressible sharp teeth are well adapted for seizing the prey and The purposes of this grouper catalogue are (1) to preventing its escape from the mouth. Some grou- provide a means of identifying the various species, pers have been observed following moray eels (and (2) to present a synopsis of the literature on the occasionally other fish) as they forage over the reef, biology and fisheries of these species, and (3) to in order to catch the small fishes and crustaceans present a new generic-level classification of the that are frightened from their hiding places by the groupers. eels. The Indo-Pacific groupers (110 species) were Except for occasional spawning aggregations, revised by Randall and Heemstra (1991), and that most species are solitary fishes: and tagging stud- work is incorporated in the present catalogue. ies have shown that groupers are generally resident Heemstra (1991) completed a taxonomic revision of on a particular reef for long periods of time (often the 14 species of groupers that occur in the eastern years). This site specificity and the relatively slow Atlantic Ocean and Mediterranean Sea. The results growth rate of groupers make them particularly vul- of this revision are also included in the present nerable to over-fishing. In addition, some groupers catalogue. The reader is advised to consult these use localized spawning sites to which they migrate two revisions for taxonomic details. from distances of several kilometres; and these sites are often exploited by local fishermen who Our treatment of the American groupers was catch large numbers of fishes during the brief greatly facilitated by the excellent revision by C.L. spawning period of 1 or 2 weeks. This removal of a Smith (1971). With a few exceptions, we recognize considerable number of reproductively active fish the same species as Smith did. Where we differ with from the population may be detrimental to sustained Smith, we have given additional data and a detailed yields of the fishery. Although an individual male explication of our taxonomic conclusions. The first may spawn several times during the breeding pe- author (P.C.H.) did the research on American grou- riod, there is no evidence to suggest that females pers and accepts full responsibility for any errors spawn more than once a year. Some species (e.g., concerning these species. Epinephelus akaara) spawn in pairs, others (e.g., E. striatus) spawn in large aggregations. 1.1 Habitat and Biology Judging from the few species that have been studied, groupers are protogynous hermaphrodites. Groupers are bottom-associated fishes found in The gonad lies ventral and slightly posterior to the the tropical and subtropical waters of all oceans. swim bladder. The ovary is in the form of a bilobed Most species occur on coral reefs, but some live in sac that unites posteriorly to form a common ovi- 2 FAO Species Catalogue Vol. 16 Subfamilies not treated in this work Fig. 1 Classification of the Family Serranidae Groupers of the World 3 duct. In a mature female, numerous oocytes are chorion, colourless unsegmented yolk and a single arrayed in lamellae surrounding a central lumen, colourless oil globule 0.13 to 0.22 mm in diameter. with spermatogenic tissue in small dormant crypts Newly hatched larvae of E. septemfasciatus (Fig. 2) on the periphery of the lamellae. After spawning as are 1.85 mm TL, and first feeding begins on the third a female for one or more years, the grouper day after hatching (2.6 mm TL). Grouper larvae are changes sex and thereafter functions as a male. At characterized by their “kite-shaped” body’(greatest sexual transition, the oocytes degenerate, the sper- body depth at origin of dorsal fin), second dorsal-fin matogonia proliferate, and the ovary is transformed spine and pelvic-fin spines greatly elongated, with into a functional testis. Evidence of the ovarian 3 or 4 serrate longitudinal ridges, well-developed origin of the testes are the remnants of oocytes and head spination (with prominent spines on the pre- the ovarian lumen, which can be seen in cross-sec- opercle and supraocular ridge), and dense tions of the testes. This protogynous mode of pigmentation on the dorsolateral surface of the body reproduction is complicated in certain species by cavity. In laboratory reared specimens, the pelagic the ‘occurrence of some large females that do not larvae of E. akaara transformed to the benthic juve- change sex and some small males that are mature at nile stage at 25 mm TL, 25 or 26 days after hatching the same size as the smallest females. An exogenous (Mito et al., 1967). But in E. septemfasciatus, the (behavioural) inducement of sexual transformation, transformation occurred at 31 mm TL, and the pe- as opposed to an endogeneous (size) threshold, is lagic larval period lasted 60 days (Kitajima et al., indicated by 1) the sexual transition occurring over 1991). In view of the shallow water bottom-associ- a broad range of size (age), and 2) the presence of ated habitat of adults and juveniles, the relatively females older than the age at which transition is long-lived pelagic larvae of groupers may provide completed for the population. the mechanism by which many species have at- tained their wide geographic distributions. The available information on the larval develop- ment of some 29 species of groupers was summarized by Kendall (1984) and Leis (1987). The fertilized eggs are pelagic, spherical, transpar- ent, 0.70 to 1.20 mm in diameter, with a smooth newly hatched larva, 1.85 mm total length 33-day old, 8.1 mm total length postlarva, 3-day old, 2.60 mm total length 60-day old, 30.8 mm total length 25-day old, 4.8 mm total length 75- day old, 49.3 mm total length Fig. 2 Larval Development stages of Epinephelus septemfasciatus (after Kitajima et al., 1991) 4 FAO Species Catalogue Vol. 16 1.2 Fisheries fisheries statistics from the Atlantic Ocean than from the Indian and Pacific oceans combined. The larg- Groupers are of considerable importance in the est commercial catch of groupers is reported from commercial, sport, and artisanal fisheries of tropical the Caribbean area (Table 2, FAO Fishing Area 31). and subtropical seas. A few species are used in aquaculture. Epinephelus coioides, E. malabaricus, From 1981 to 1990 there has been a trend of E. akaara, E. striatus, E. septemfasciatus, Cromilep- increasing landings of groupers (Table 3). This is tes altivelis, and Mycteroperca microlepis have been generally true for all species or categories reported, spawned in captivity. Several species are com- except for Epinephelus morio from the Gulf of Mex- monly used in cage-culture operations. ico which appears to be in decline. The protogynous mode of reproduction in grou- pers presents problems for fishery management. Male groupers (which are produced by sexual trans- 1.3 Classification of the Family Serranidae formation of old females) are usually larger, older The composition and phylogenetic relationships and less numerous than females; and the commer- of the Family Serranidae were discussed by cial, sport and subsistence fisheries are often Johnson (1983, 1988): Kendall (1984), and Leis biased (by means of hook size and fishing tech- (1986). Johnson (1983) proposed that the Serrani- niques) towards the capture of large adults.