BBSR
Marine Invertebrates of Bermuda

Caribbean Spiny Lobster (Panulirus argus)

by Caitlin Houlihan
and
James B. Wood (Ed)


Abstract  Taxonomy  Habitat  Ecology  Recent Research  Commercial Importance  Bermuda Laws  Personal Interest  References  Links 


Caribbean Spiny Lobster Panulirus argus

Abstract


Panulirus argus, or the Caribbean Spiny Lobster, is a genus of spiny lobster found in Bermuda. Its common name is attributed to the many spines that cover both the body and antennae of the marine invertebrate (Colin 1978). This species is nocturnal in its habits and hides in protective habitats such as coral reef crevices and seagrass beds during the day (Marx and Herrnkind 1986). Unlike other lobster P. argus does not possess large claws used in catching prey. Rather, chemoreceptive setae and a complex nervous system are utilized in finding food (Crawford and De Smidt 1922). The Caribbean Spiny Lobster has a complex life cycle that is composed of four phases from pelagic larvae to benthic adult. Adult P. argus form aggregations that migrate across the Bermuda shelf in order to mate and start the life cycle over again (Marx and Herrnkind 1986). Large aggregations of lobster are subject to both commercial and sport fishing, which has greatly reduced the overall population of P. argus. Therefore, many laws have been formed in Bermuda to protect this species from overfishing (Evans and Evans 1995).

Taxonomy


Phylum: Arthropoda
  Subphylum: Mandibulata
    Class: Crustacea
      Subclass: Malacostraca
        Order: Decapoda
          Family: Palinuridae


Habitat


Panulirus argus commonly inhabits tropical and subtropical waters of the Atlantic Ocean from North Carolina to Brazil, including the Caribbean Sea, Bermuda, and the Gulf of Mexico (Marx and Herrnkind 1986). In its ranging habitat, P. argus is generally found in shallow waters ranging from low tide to about 90 meters (Sterrer 1986). Since the spiny lobster is nocturnal in its foraging habits, it remains hidden during the day in protective reef recesses (Crawford and De Smidt 1922). Coral reef crevices, ledges, overhangs and other discontinuities in hard substrates serve as daytime dens (Florida Fish and Wildlife Conservation Commission 2006). Although the adult lobsters live on the reef, early benthic larvae and juveniles are found in macroalgae beds along rocky shorelines and may be interspersed among large expanses of seagrass. Seagrass beds typically serve as nurseries for the developing lobster (Marx and Herrnkind 1986).

Ecology


Panulirus argus obtains its common name, Caribbean Spiny Lobster, from the numerous spines that cover its carapace and antennae (Colin 1978). The carapace (the hard shell covering the cephalothorax), the abdomen and telson (tail) are the three sections that make up the spiny body of P. argus. Unlike many other forms of lobster, the spiny lobster lacks large claws. Rather, the legs all end in sharp dactyls which bear tufts of setae. The calcareous exoskeleton of the lobster varies in coloration from light gray and tan to red and deep browns depending on maturity (Crawford and De Smidt 1922

The life history of the spiny lobster consists of four phases: planktonic phyllosome larvae, swimming postlarval pueruli, benthic juvenile, and adult. Each has a distinctive behavior and habitat that is characteristic of that stage in the life cycle (Marx and Herrnkind 1986). The cycle begins with mating of two adults that are both physiologically and functionally mature (Evans et al. 1995). In Bermuda, mature spiny lobsters mate mid-April to mid-May, and in June egg-bearing females move to the edge of the reef platform to spawn (Sterrer 1992). The mating individuals require high shelter, suitable water conditions, and adequate larval transport. Once a suitable substrate is found, a brief courtship occurs and copulation takes place. Copulation consists of the male lobster adhering a gray spermatophoric mass to the sternum of the female while holding her against his sternum. The female then expels eggs through her gonopore and fertilizes them by scratching at the spermatophore (Marx and Hernnkind 1986).

The phyllosome larva hatch as transparent spider-looking plankton. These flattened larva molt 11 times while floating in the water column for a year or more. The phyllosoma then settle and becoming swimming pueruli (Sterrer 1992). Puerli molt and become benthic juveniles when they encounter suitable inshore substrate, such as mangrove roots or seagrass beds. Early benthic lobsters are solitary but soon become aggregative and migrate offshore where they develop into adults. Molting continues to occur in adults when growth is necessary (Marx and Herrnkind 1986).

Molting within crustaceans is necessary for growth and occurs throughout the lifecycle. Generally, molting and the frequency of molts decline in P. argus with age. Molting cycles vary between sexes and are dependent upon size of the lobster and surrounding water temperature. The molting process consists of four stages. Intermolt, or Anecdysis, is the period between molts where the lobster grows to the limits of the exoskeleteon. In the Premolt, or Proecdysis, stage of molting the lobster prepares to shed the old exoskeleton and produces the first layers of the new exoskeleton. Ecdysis is the actual molting step where the animal is vulnerable. Finally, Metecdysis consists of expanding new tissue and hardening the new exoskeleton (Crawford and De Smidt 1922, Marx and Herrnkind 1986).

Carribbean Spiny Lobsters are night scavengers. The diet of adult lobster often consists of slow-moving and sedentary animals including bivalves, chiton, gastropods, small mollusks, small crustaceans and echinoderms. However, they have also been known to eat carrion and bits of fish from the ocean floor. The powerful mandible aides in crushing any mollusk shells or other protective armor of prey (Eggleston et al. 2003, Crawford and De Smidt 1922, Marx and Herrnkind 1986). P. argus larva have different diets than the adult lobsters. Larvae tend to eat other planktonic marine organisms such as chaetognaths, euphasiids, fish larvae, medusae, and ctenophore. A complex nervous system enables adult spiny lobsters to identify and discriminate between natural food odors. Chemoreceptive setae line the antennules (small antennae that extend forward from under the eyes), second antennae, legs, and mouthparts and assist in locating food (Derby et al. 2001).

The spiny lobster, at all life stages, is the prey of numerous marine organisms. The greatest losses occur during larval development, when substantial numbers are eaten by pelagic fish. Grouper, mutton fish, jew fish and loggerhead turtles are all known to eat adult spiny lobster (Crawford and De Smidt 1922, Marx and Herrnkind 1986).

One of the most interesting aspects of the spiny lobster behavior is their tendency to aggregate and migrate into deeper waters. This exodus usually happens after the first fall storm and is thought to occur in order to move away from the cold conditions in shallow water (Sterrer 1992). Other possible causes for migration include molting and mating (Crawford and De Smidt 1922). Bermudan spiny lobsters migrate across the island shelf oriented downstream in single file, so as to reduce drag (Evans and Lockwood 1996).

Recent Research


Recent research on Panulirus argus mostly consists of monitoring fishing, including Bermuda fisheries, in order to keep the spiny lobster population under control. There is growing concern about the damaging effects of fishing on reef habitats. Supervising the P. argus population also includes studies upon the social behavior and migratory patterns of the Caribbean Spiny Lobster. Knowledge of the migratory pattern of an exploited marine species is required for effective management (Evans and Lockwood 1996).

Commercial Importance


Panulirus argus is both a sport and commercial species, but its importance to the commercial fishing business is much more evident. The Caribbean Spiny Lobster supports important commercial fisheries throughout most of its range from Bermuda to Brazil (Eggleston et al. 2003). Landings of P. argus in Bermuda have varied during past years, from a record year in the 1999/2000 season of 36,515 lobsters to a low of 17,393 lobsters in the 2001/02 season (Trott et al. 2002). Besides being caught for food for human consumption, the spiny lobster can be used as bait for many fishes and other marine animals (Crawford and De Smidt 1922). Therefore, P. argus assists in bringing in other marine stock for commercial fisheries.

Bermuda Laws


The Western Central Atlantic Fishery Commission, in Sepetmber of 2000, held a workshop and found that Panulirus argus is being over-exploited throughout much of its range. There is an urgent need to control, and in many cases reduce, the fishing effort in lobster fisheries. Bermuda has already started to make efforts towards protecting this species. The principal stock conservation measures have included protection of P. argus juveniles in inshore spiny lobster nursery areas, a minimum size limit of 92 millimeter carapace length, a 5-month closed season covering the breeding season, and the protection of egg carrying females (Evans and Evans 1995).

A permanent limited entry fishery for Panulirus argus was created in Bermuda in 1996. This fishery only allows a maximum number of 20 lobster license holders with a set amount of traps that varies each year depending on Spiny Lobster numbers (FAO 2000). In order to reduce the amount of lobster fishing to an even greater extent the establishment of a refugium in the inshore lagoons, sounds, and harbors of Bermuda was implemented where trapping of P. argus is prohibited. This natural refugee is one of the most important conservation measures created in Bermuda to protect the P. argus species and is valuable to spiny lobster survival, growth and propogation (Evans and Evans 1995).

Personal Interest


On one of my first night snorkels in Bermuda at Whalebone Bay, I discovered a solitary Spiny Lobster foraging on the seafloor. It was very interesting to observe the spine covered body of the Caribbean lobster and to see that it had no large front claws like the Maine lobster that I am accustomed to. I was also fortunate enough to see the organism swim using its pleon, or tail, when it was startled. It moved very rapidly away from me because it assumed I was a predator. I was excited to find a few more Panulirus argus that same night. Since it was one of the first marine organisms I identified by myself in Bermuda, I figured P. argus would be an interesting marine invertebrate to study in more detail for my web project.

References

Colin, P.L. 1978. Caribbean Reef Invertebrates and Plants. New Jersey: T.F.H Publications, Inc. Ltd.

Crawford, D.R. and W.J.J De Smidt. 1922. The spiny lobster, Panulirus argus, of southern Florida: its natural history and utilization. Bull Bur. Fish. (U.S.). 38: 281-310.

Derby, C.D., P Steullet, A.J. Horner and H.S. Cate. 2001. The sensory basis of feeding behaviour in the Caribbean spiny lobster, Panulirus argus. Mar. Freshwater Res. 52: 1339-1350.

Evans, C.R. and A.J. Evans. 1995. Fisheries ecology of spiny lobsters Panulirus argus (Latreille) and Panulirus guttatus (Latreille) on the Bermuda Platform: estimates of sustainable yields and observations on trends in abundance. Fish. Res. 24: 113-128.

Evans, C.R., A.P.M. Lockwood, A.J. Evans and E. Free. 1995. Field studies of the reproductive biology of the spiny lobster Panulirus argus (Latreille) and P. guttatus (Latrielle) at Bermuda. Journal of Shellfish Research. 14(2): 371-381.

Evans, C.R. and A.P.M. Lockwood. 1996. Long-term migratory behavior of undersized spiny lobsters Panulirus argus (Latreille) on the Bermuda island shelf. Gulf of Mexico Science. 14(1): 35-39.

Eggleston, D.B, E.G Johnson, G.T. Kellison, and D.A. Nadeau. 2003. Intense removal and non-saturating functional responses by recreational divers on spiny lobster Panulirus argus. Mar. Ecol. Prog. Ser. 257: 197-207.

FAO. 2000. Report of the workshop on management of the Caribbean spiny lobster (Panulirus argus) fisheries in the area of the Western Central Atlantic Fishery Commision. Merida, Mexico: University Marist of Merida. FAO Fisheries Report No. 623.

Marx, J.M and W.F. Herrnkind. 1986. Species profiles: life histories and environmental requirements for coastal fish and invertebrates (South Florida), spiny lobster. Biol. Rep. 82(11.61).

Sterrer, W. 1992. Bermuda’s Marine Life. Flatts, Bermuda: Bermuda Zoological Society.

Sterrer, W., Ed. 1986. Marine Fauna and Flora of Bermuda: A Systematic Guide to the Identification of Marine Organisms. New York: John Wiley & Sons.

Trott, T, B.E. Luckhurst and P. Medley. 2002. Report of the second workshop on management of the Caribbean spiny lobster fisheries in the WECAFC: spiny lobster fishery of Bermuda. Havana, Cuba. FAO Fisheries Report No. 715.

Links

MarineBio.Org
Wikipedia
Fish and Wildlife Research Institute
Smithsonian Marine Station at Fort Pierce