A SUMMARY OF BIOLOGICAL AND FISHERY DATA ON RED HIND (ZEEMEUM GUTTATUS) AND CONEY (MBUDMIIS STOCKS IN THE U.S. VIRGIN ISLANDS by Stephania K. Bolden March 1994 National Oceanic and Atmospheric Administration National Marine Fisheries service Southeast Fisheries Science Center 75 Virginia Beach Drive Miami, Florida 33149 Contribution: MIA-93/94-32 INTRODUCTION Red hind (ERinephelus guttatus) and coney (formerly Epinepbelus but re-classified as CephaloRholis fulva, (Heemstra and Randall, 1993)) were chosen for this investigation because of their representation of the grouper complex in the U.S. Caribbean fishery and their recent decline in length at capture. These species are the serranids most often landed in both Puerto Rico and the U.S. Virgin Islands (USVI) and represented 81% of the total serranid catch samples in 1990 (Appeldoorn et al. , 1992). Red hind is believed to have replaced the Nassau grouper (F^ striatus) in the fishery, and has become the dominant grouper in recent U.S. Caribbean landings (Beets and Friedlander, 1992). Because coney is ecologically and biologically similar to red hind, and because both red hind and coney are caught by the same gear in the same area, this assessment also investigates the status of coney. This report only addresses the USVI fisheries. A comparable assessment of the Puerto Rico red hind fishery can be found in Sadovy (1993) and Sadovy and Figuerola (1992). Notably, coney assessments from Puerto Rico are lacking. Traditionally, the tropical shelf of the USVI has supported a small-scale fishery. The reef fish communities of the Caribbean provide the only immediate source of fresh reef-fish for the island and the increasing population of the USVI adds demand to the already stressed Caribbean fisheries. In recent years more people, along with newer boats equipped with more efficient gear, have greatly increased the density of fishers on the limited fishing 2 grounds (Goodwin, 1988). Small platforms surrounding islands with large population densities can be easily overexploited. This status report was prompted by an observed decline in size- of harvested fishes from the U.S. Caribbean (Olsen and LaPlace, 1978; Clavijo et al., 1986; Beets at al.,1990; Appeldoorn et al., 1992; Beets and Friedlander, 1992; Sadovy and Figuerola, 1992). This inquiry was prepared to meet Shallow-Water Reeffish Fishery Management Plan (SWRFFMP) requirements . of continued monitoring by the National Marine Fisheries service (N"S) . OBJI=IVES This report is a review of red hind and coney literature and investigates the status of fisheries data for the USVI. This report, coupled with the recent work of Sadovy (1992, 1993), represents a summary of the literature on the status of the grouper complex representatives in the U.S. Caribbean. This report complements the red hind and coney resource assessment prepared by the NMFS, Southeast Fisheries Science Center (SEFSC) in 1994. STOCK GROUPS Grouper stocks are particularly vulnerable to exploitation because of their life history characteristics (Colin et al., 1987; Bannerot at al., 1987; Manooch, 1987; Ralston, 1987; Bohnsack, 1989). The long-lived, slow growing protogynous nature of groupers coupled with intensive short-term fishing of spawning aggregations, renders groupers especially vulnerable to overexploitation. 3 Because they exhibit protogyny (sequential hermaphroditism in which an individual transforms from female to male), groupers can be particularly effected by fishing which may ultimately reduce mean individual size. This reduction in mean size decreases the number of males in the stock since males are generally larger than females. If male genetic material is limiting and if sex change is controlled by size (or age) , then a heavily fished stock may not be able to compensate for the differential removal of the larger males. If, on the other hand, sex change is behaviorally induced, then a decline in males may be compensated for by increased numbers of females changing sex. However, this could result in a decline in mean female size leading to a reduction in stock egg production. The unit stock for this report was determined by species: red hind and coney. Although the two major islands of the USVI (St. Thomas and St. Croix) could potentially support distinct red hind and coney stocks, not all available data are island discrete. These two islands lie on separate geological platforms and are separated by approximately 65 km (40 miles). Known tagging studies have not been conducted to examine mixing of grouper stocks between St. Thomas and St. Croix, nor are any morphological or physiological characteristics known which indicate discrete stocks. Both major islands reportedly have spawning aggregation sites for E. g=atus; on their insular platforms (Beets and Friedlander, 1992). However, there has been no formal investigation of synchronous spawning or abundance of either the red hind or coney during peak spawning periods at St. Thomas and St. Croix. 4 Migration to spawning aggregation sites is well known for F, g =atus (Colin et al., 1987; Sadovy et al., 1992). Considerable distances may be traveled by F. auttatus to spawning sites - one reportedly travelled 18 ka (11.2 miles) (Sadovy et al., 1992). BIOLOGY Generally speaking, groupers (Serranidae) are unspecialized carnivores (Thompson and Munro, 1974), that are slow growing. and live relatively long lives (Sadovy and Figuerola, 1992). They attain a large size at sexual maturity, and are generally protogynous hermaphrodites. Because they aggregate to spawn (Colin et al., 1987) they are, at times, relatively easy to catch and thereby susceptible to a wide range of sizes (mesh and hook) and types of fishing gear. Red hind and coney are groupers possessing the aforementioned life history characteristics which collectively make the groupers extremely susceptible to overfishing. The geographical distribution of the red hind and coney overlap. Both are found in the tropical western Atlantic from North Carolina to Venezuela (Heemstra and Randall, 1993). However, the distribution of coney is more extensive than red hind and is also found in Bermuda and along the South American coast to southern Brazil, including Atol das Rocas (Heemstra and Randall, 1993). Larval life for groupers is from 3 - 8 weeks. Little is known of critical juvenile habitat for the majority of grouper species, nor of their principal settlement periods. Settlement may be 5 assumed to occur from 3 - 8 weeks after spawning (Colin et al., 1987). The presence of red hind males as young as the youngest mature female indicates some males may be diandric (Sadovy et al., 1993), however the event is likely to be rare (Sadovy et al., 1994). Female red hind are determinate spawners (all oocytes for the spawning period are present at the beginning of the season) and may spawn more than once during the spawning season (Sadovy et al., 1993). Adult red hind and coney are often associated with rocky and coral reefs areas in relatively shallow waters and are basically sedentary unless foraging. Juvenile red hind have been observed in shallow rocky, rubble and sandy areas. Juvenile coney (3 - 4 cm TL) have been observed camouflaged in filamentous algal growth on shallow (10 m) artificial cement module reefs (pers. obs.). Both red hind and coney are protogynous hermaphrodites (Smith, 1959; Nagelkerken, 1979; Shapiro, 1987). Both species spawn over a limited period, perhaps reliant to the first full moon of the calendar year (Table 1). Al though mature, ripe ovaries of red hind in Puerto Rico have been found over a three-month period, spawning acti vi ty is limited to about 2 weeks each year (Sadovy et al., 1993). Red hind is a pair spawner in single male/multi-female clusters which forms short-term spawning aggregations (Burnett- Herkes, 1975; Colin et al., 1987; Sadovy et al., 1992; Shapiro et al., 1993; Sadovy et al., 1994). The reproductive activity of coney is not as well documented with only a single pair spawning reported (Colin et. al., 1987; Colin and Clavijo, 1988). A 6 summation of basic lif e history parameters for both species are presented in Table 2. Table 1. Spatial and temporal summary of spawning observations for red hind (ERineRhelus guttatus) and coney (CephaloRholis fulva). 2MES TM LOCIM 3VMGUM L q9ta Jan-Feb** Puerto Rico Colin at al., 19V auttatus Feb-Jun* Jamica Kanro at al., 1973 Jan Puerto Rico Erdsan, 1956 Jan Janice Thospson and Kunro, 1974 L. tun Dec Puerto Rico Erdnan, 1956 fulva Jan Puerto Rico Colin and Clavijo, 1988 fulva Jan Babasas Colin, 1982 fulva Jan-Kar Jaimica Thoapson and Mairo, 1978 C. fulva may-Aug Bersuda Siith, 1971 *presence of ripe fish, not actual spawning **noted lunar phase as fall toon Length-f requency distributions of male and female red hind and coney show that the males are of larger average size than the females, although there is a broad overlap in the length distribution of the sexes (Thompson and Munro, 1974). In both species the percentage of males increases steadily with total length: most red hind greater than 40 cm TL are males (Heemstra and Randall, 1993). The red hind Puerto Rico stock have been determined as having a 13:1 (F:M) ratio with 93% of captured red hind being female (Puerto Rico Dept. of Natural Resources, unpubl. data), and more recently a 3.25:1 (F:M) ratio (Sadovy et al., 1994). This variation in female:male ratios suggests an influx of males, and/or egress of females and is a common serranid event. The coney stock of Puerto Rico was found to be mostly female (78%) with a 3:6:1 (F:M) ratio (Puerto Rico Dept. of Natural Resources, 7 unpubl. data). Red hind in st. Thomas are long-lived and attain their maximum size slowly, after fast growth during the first year (Sadovy et al., 1992). Ages were validated by marginal increment on otoliths and determined to be deposited annually (in spring/summer) on adult and juvenile red hind taken by trap and hook-and-line in the u.s.