Guinea Chick Lobster

Spiny lobsters (Palinuridae) are nocturnal animals that strongly depend on daytime shelter (“dens”) for survival. These lobsters, however, do not construct their own dens and must use available structured refuges, such as solution holes, coral heads, large sponges, and crevices among rocks and coral reefs. Consequently, den sharing by conspecifics is common. The Spotted Spiny Lobster is a reef-obligate throughout its entire benthic life (i.e., across the entire size range of 10 to 90 mm carapace length) and is more common at depths of <15 meters (Sharp et al. 1997; Acosta and Robertson 2003). Individuals are sedentary and have a limited home range (Lozano- Álvarez et al. 2002). They also have slender antennae, a shy defensive behavior, and do not show group defense, either within dens or in the open (Lozano-Álvarez and Briones-Fourzán 2001; Briones-Fourzán et al. 2006). Their main defensive strategy, whether sheltering singly or in groups, depends on retracting as deeply as possible into the den. Exposed Spotted Spiny Lobsters, upon perception of risk, quickly retreat into the nearest available den or escape by tail flipping. The tendency of Spotted Spiny Lobsters to aggregate appears to decrease with increasing size, as does the tendency to share dens, suggesting that this species relies more on hiding, alone, to avoid predation, than does the Caribbean Spiny Lobster.(Briones-Fourzan and Lozano-Alvarez 2008)

Lozano-Alvarez et al. (2002) studied homing and orientation in the Spotted Spiny Lobster through experimental displacements of individual lobsters.They concluded that the familiar home range of the Spotted Spiny Lobster appears to lie within a radius of 100 meters along the reef tract. A tethering experiment showed that lobsters moved toward the reef when released on bare sand 500 meters away from the reef. Wave surge may have oriented the lobsters towards the reef. These results indicate that, despite their sedentary, non-migratory nature, adult male and female Spotted Spiny Lobster do show some homing and orientation abilities.

Briones-Fourzan et al. (2006) found that the Caribbean Spiny Lobster uses a wider variety of shelters than does the Spotted Spiny Lobster because the former may take refuge in any crevice as long as it protects its abdomen, whereas the latter prefers deep shelters ithat permit a full retreat. In addition, Caribbean Spiny Lobsters tend to remain on the floor, close to the entrance of the
shelter with their antennae emergent, thus remaining more visible than the Spotted Shiny Lobster, which tends to occupy the far recesses of the den away from the entrance, often clinging to the ceiling or walls.

Unlike the true, or clawed, lobsters, spiny lobsters have long, thick, spiny antennae and lack large pinching claws. The Spotted Spiny Lobster (Panulirus guttatus) occurs from Bermuda to Suriname, with populations in southeastern Florida, in the Bahamas, and throughout the Caribbean Sea. Unlike the Caribbean Spiny Lobster (Panulirus argus), which has a largely overlapping distribution, P. guttatus is of limited commercial interest throughout most of its range. On some islands, however, it contributes significantly to satisfying the demand for luxury seafood. The main fisheries for this species are around Bermuda and Martinique, although limited fisheries probably exist elsewhere. (Sharp et al. 1997 and references therein; Briones-Fourzan and Contreras-Ortiz 1999; Wynne and Cote 2007)

Panulirus guttatus is an obligate reef-dweller, rarely leaving the confines of the reef, and found especially on the fore reef. Several early studies of P. guttatus in Florida investigated the sex ratio, size distribution, and reproductive seasonality of a population living at man-made jetties near Miami Beach. Based on data from their study in the Florida Keys, Sharp et al. (1997) concluded that an individual P. guttatus spends its entire benthic life on a small portion of the fore reef, perhaps even on a single spur. Panulirus guttatus adults forage on the reef at night. They spend the day in dens that extend deep into the reef. There is some indication that males may guard den entrances to protect harems of females from other males. This behaviour has been observed in P. argus both in the laboratory and in the field. The sheltering requirements of P. guttatus appear to be much more specific than those of P. argus. This restriction of acceptable shelter characteristics for P. guttatus may be the primary factor controlling the abundance of this obligate reef-dweller. (Sharp et al. 1997 and references therein; Briones-Fourzan and Contreras-Ortiz 1999)

Robertson and Butler (2003) dove at night on patch reefs in the Florida Keys (U.S.A.) to collect lobsters when they were most accessible and used mark-recapture methods to estimate their growth and size at maturity. Molt increment (i.e., growth between molts) for lobsters greater than 50 mm carapace length (CL) was estimated to be 1.5 mm for females and 1.6 mm for males, while molt interval was 50.6 weeks for females and 50.0 weeks for males. Growth rate was calculated to be 0.02-0.37 mm CL/week, depending on size and sex. On average, males grew faster than females, but the rate of growth decreased with increasing size for both sexes. Female size at maturity was estimated at 32 mm CL, based on both the minimum size of egg-bearing females and the size at which 50% of the females produced eggs. Estimated size at maturity for males was 36 to 37 mm CL, using the onset of allometric growth of the second walking leg as an indicator of male maturity. The Spotted Spiny Lobster is a small species, and its size at maturity is small compared to other species of spiny lobster, although its growth rate is comparable to other species. These unusual life history characteristics may reflect selection for traits advantageous to life in small, architecturally complex habitat patches. The postlarvae recruit directly to small holes on the underside of coral heads and appear to remain resident on the reef for their entire life. The dependency and local residency of this species on a single, often patchy habitat type lies in stark contrast to most other well-studied species of spiny lobster, which are typically nomadic and exhibit ontogenetic (developmental) shifts in habitat during their life cycle. (Robertson and Butler 2003 and references therein)

The antennular plate has 2 widely separated large spines. The exopod of the third maxilliped is reduced and bears no flagellum. There is no pubescent area on the abdominal somites behind the transverse groove. The anterior margin of the pleura of abdominal somite 2 two lacks distinct teeth. The transverse grooves of the abdominal somites have straight margins, not crenulated. Transverse grooves of abdominal somites 2 to 4 join the groove along the anterior margin of the corresponding pleuron. The body, especially the abdomen, has dark purple with numerous very conspicuous rounded whitish spots. The legs are spotted on the carpus, merus, and ischium, without streaks there; the propodus is longitudinally striped. (Holthuis 1991)

The Spotted Spiny Lobster (Panulirus guttatus) is found in the Western Atlantic: Bermuda, Bahamas, South Florida, Belize, Panama, Caribbean Arc from Cuba to Trinidad, Curaçao, Bonaire, Los Roques, Suriname (Holthuis 1991).

The Spotted Spiny Lobster (Panulirus guttatus) and the Caribbean Spiny lobster (P. argus) co-occur throughout the Caribbean Sea, the Bahamas, and Bermuda (Holthuis, 1991). Both species exhibit gregarious social behaviour, wherein two or more individuals co-den. But whereas the Caribbean Spiny lobster has several changes in habitat during its ontogeny and is a highly migratory species, the Spotted Spiny Lobster is a sedentary, typically non-migratory species that dwells in the coral reef habitat throughout its entire benthic life. Moreover, the Spotted Spiny Lobster is highly reclusive, only leaving its shelter for short periods during darkness. (Lozano-Alvarez et al. 2002 and references therein)

Adult Spotted and Caribbean Spiny Lobsters have similar diets in terms of gross taxonomic groups, but the species composition in each group could be different because the two lobster species feed in different habitats. The Caribbean Spiny Lobster forages on seagrass beds, rubble, and gravel areas, but rarely in the coral reef itself. In contrast, the Spotted Spiny Lobster is rarely seen foraging outside the coral reef structure. it is possible that the pueruli larvae of the two species do not choose the same settlement substrata (shallow substrata with marine vegetation versus settling directly onto the coral reef habitat). Some pueruli matching those described for the Spotted Spiny Lobster have been observed in small holes in coral reefs of Florida. (Briones-Fourzán and McWilliam 1997 and references therein)

The Spotted Spiny Lobster (Panulirus guttatus) is a shallow water species, inhabiting rocky areas, mainly in crevices (Holthuis 1991).

Juvenile and adults Spotted Spiny Lobsters are restricted to coral reef habitat, mostly in the top 5 to 10 meters (Briones-Fourzán and McWilliam 1997; Sharp et al. 1997).

The size at maturity for both male and female Spotted Spiny Lobsters is small relative to other tropical species of spiny lobster. However, the age at maturity for this species is similar to other tropical spiny lobsters, suggesting the small size of this species may be the result of adaptive trade-offs. Because this lobster spends both its juvenile and adult life on coral reefs, its small size increases its ability to shelter in the many crevices on the reef. In addition, the fact that this species does not migrate may also influence the size at which it matures. (Robertson and Butler 2003 and references therein)

Acosta and Robertson (2003) studied the Spotted Spiny Lobster (Panulirus guttatus) on Glover's Reef Atoll, Belize. Commercial fisheries for Spotted Spiny Lobsters are currently being considered for development, but Acosta and Robertson present data suggesting that such fisheries might be relatively unproductive and could lead to rapid localized extinctions. The related Caribbean Spiny Lobster (P. argus), the main commercial spiny lobster in the Americas, uses a variety of coral reef habitats, but Spotted Spiny Lobsters are habitat specialists restricted to shallow reef habitat. The conservation needs of both species are similar in that both require large protected areas. However, Caribbean Spiny Lobster requires large areas with heterogeneous habitats including coral reefs and seagrass beds, whereas the Spotted Spiny Lobster requires large areas of coral reef habitat. Fisheries for Spotted Spiny Lobster are currently conducted with limited regulations in Bermuda and Martinique and efforts are underway to create new fisheries for this species in other countries. No fishery regulations currently exist for this species in most Caribbean countries.

Wynne and Cote (2007) found that Spotted Spiny Lobster populations in Anguilla (British West Indies) are affected by both habitat quality and fishing intensity. Foraging lobsters were generally associated with reef areas of high structural complexity with limited cover of macro-algae, sediment, and sand. Reefs with these habitat characteristics supported denser populations of lobsters than other reefs. Fishing pressure affected only mean individual lobster size (not lobster population density), with large lobsters present only at sites fished at low intensity (habitat quality did not show a significant effect on mean individual size, as it did on population density). The authors suggest that the fact that Spotted Spiny Lobster densities on heavily exploited, high-quality reefs still far exceeded those on poor-quality reefs that were lightly exploited means that any effort at managing this species must incorporate knowledge of habitat quality. Pockets of high-quality habitats in Anguilla currently appear to yield most of the catches of Spotted Spiny Lobsters, but it is not clear whether this fishery will be sustainable in the long term because both tourism and the demand for lobster products are growing rapidly. The lack of an observable effect of fishing on lobster population densities may be because the sites most intensively targeted are high-quality habitats. Fishing has probably reduced lobster densities on high-quality reefs to a greater extent than on low-quality reefs, but the high productivity of good-quality sites is still sustaining more intense fishing. The importance of habitat quality in sustaining Spotted Spiny Lobster populations in the face of intense exploitation suggests that management efforts should be aimed at enhancing reef health. This may be achieved through the establishment of no-take areas on good-quality reefs. However, such actions could generate conflicts with stakeholders because these reefs are currently those most heavily exploited. (Wynne and Cote 2007 and references therein)

Sharp et al. (1987) estimated the density of Panulirus guttatus on the Looe Key fore reef (Florida) to be between 118 and 363 lobsters per hectare. This density range represents only the adult population; juveniles were rarely observed during the study, and the few that were observed were not tagged. Thus, the overall abundance of the population is undoubtedly higher. These density estimates are the first for P. guttatus derived directly from observations by divers, rather than from trapping (a previous estimate from trapping on a reef in Bermuda was much lower, around 29 lobsters per hectare). (Sharp et al. 1987 and references therein)

Egg-bearing females of the Spotted Spiny Lobster (Panulirus guttatus) occur year-round (Acosta and Roberstson 2003). Females with eggs in all developmental stages (bright orange to dark brown) are found in the coral reef barrier but not outside the refuge provided by the reef. It is possible that eggs hatch in this inshore habitat. In contrast, egg-bearing females of the Caribbean Spiny Lobster (Panulirus argus) tend to move to deeper areas to hatch their eggs. (Briones-Fourzán and McWilliam 1997 and references therein)

The smallest egg-bearing female observed by Sharp et al. (1987) had a 38 mm carapace length (CL), and some as small as 32 mm CL have been found at patch reefs in Florida (Sharp et al. 1997 and references therein). Based on data from Sharp et al., P. guttatus males become functionally mature at a larger size (~48 mm CL) than do females. This characteristic is common among palinurids; males apparently must be at least as large as their potential mates for copulation to be successful. Panulirus guttatus spawns year-round throughout most of its range, and repetitive spawning without moulting is common. Egg-bearing females were observed by Sharp et al. at Looe Key (Florida) throughout the year, with the peak in activity occurring from March through June. More than 80% of the mature (38 mm or greater CL) females spawned during these months, and many of those lobsters had both ripe ovaries and either eggs or remnants of eggs, suggesting repetitive spawning. Similarly, in an older study, egg-bearing P. guttatus females were observed on a man-made jetty at Miami year-round, except for a one month interval during September and October, and the peak reproductive period was again from March through June. Repetitive spawning without moulting, evidenced by lobsters with both ripe ovaries and external eggs or egg remnants, was also noted there. Egg-bearing P. guttatus females were observed in Martinique in all months except September during a study conducted between January and October. In contrast, reproduction of P. guttatus in Bermuda has been reported to be distinctly seasonal, with no egg-bearing lobsters during winter or spring. This truncated reproductive season may reflect environmental influences, primarily cooler temperatures and a shorter photoperiod. Similar variations in the reproductive season have been reported for P. argus, which reportedly spawns year-round in Jamaica, but is more seasonal in more northern portions of its range, including Florida. Reproductive activity among smaller mature females (45 mm or greater CL) at Looe Key was confined largely to the peak reproductive period (March to June), and no reproductive activity among smaller females was evident from November through February. These smaller females apparently produce only a single brood per season. (Sharp et al. 1987 and references therein)

Briones-Fourzan and Contreras-Ortiz (1999) studied Panulirus guttatus in northern Quintana Roo, on the Caribbean coast of Mexico. In a sample of 159 egg-bearing females, brood size ranged from 27,560 eggs for a 44.6-mm CL female, to 188,440 eggs for a 72.0-mm CL female.

The maximum total body length of the Spotted Spiny Lobster is about 20 cm, commonly to 15 cm (Holthuis 1991).

In addition to threats from habitat loss and (if a major fishery develops for this species) overfishing (Acosta and Robertson 2003), a potential threat exists from increasing demand for ornamental decapod crustaceans, including Panulirus species, for the aquarium trade (Calado et al. 2003).

Evans and Evans (1995) reported that data on catch per unit effort for the Panulirus guttutus spiny lobster fishery on the Bermuda Platform appeared to indicate an overall decline between 1975 and 1987, although there were substantial fluctuations during that period.

Acosta and Robertson (2003) found that the density and biomass of spotted lobsters P. guttatus in shallow reef habitats at Glover’s Reef, Belize, were stable but low over time, compared to those of Caribbean Spiny Lobster.

The species is taken throughout its range, but mainly incidentally; there is no special fishery for it in most areas. It is taken by hand or speared and occasionally caught in traps, mostly those set for other species. It is marketed fresh and used primarily for local consumption. (Holthuis 1991)

Panulirus guttatus, the spotted spiny lobster or Guinea chick lobster, is a species of spiny lobster that lives on shallow rocky reefs in the tropical West Atlantic and Caribbean Sea.