BIOLOGY OF THE SPINY LOBSTER- 



By F. G. Walton Smith, Marine Laboratory, University of Miami 



The spiny lobster, or crawfish, of the Gulf of 

 Mexico and the Caribbean belongs to a family of 

 shellfish which is related to the true lobsters and 

 which is to be found in the warmer seas throughout 

 the world. Some members of this family are com- 

 mercially valuable and support fisheries in South 

 Africa, Australia, California, Hawaii, Japan, and 

 the Caribbean region, including Florida and the 

 Bahamas where they are variously known as rock 

 lobster or spiny lobster, sea crayfish, langouste, 

 and langosta. They are referred to as spiny lob- 

 sters because of their similarity to the true or 

 northern lobsters from which they are distin- 

 guished by the presence of numerous spines on 

 their bodies and legs and by the absence of large 

 claws. Whereas in the true lobsters the edible 

 meat is mainly taken from the claws, the chief 

 edible portion of the spiny lobster is the tail 

 muscle. Although related, spiny lobsters must 

 not be confused with the smaller fresh-water 

 shellfish utilized commercially in a number of 

 countries under the name of crayfish. For this 

 reason, the term spiny lobster is to be preferred. 



Color varies with age and the type of bottom 

 upon which the animals live. Brighter, greenish, 

 or sandy colored animals are usually found on 

 sandy bottom or in shallow water. Darker 

 animals with a greater proportion of blue and 

 brown are found in darker bottom or in deeper 

 water. 



The Gulf of Mexico species, Panulirus argus 

 (Latreille), is found on the western Atlantic 

 shores from Rio de Janeiro, Brazil, throughout 

 the West Indies to Florida, and rarely as far north 

 as North Carolina. Although occasionally present 

 in other parts of the Gulf of Mexico, they are only 

 abundant in the Florida Keys. 



Small numbers of related species are occasionally 

 taken in the commercial catches but usually pass 

 unnoticed. Panulirus laevicauda Latreille and 

 Panulirus guttatus Latreille are most frequently 



' Contribution No. 110 from the Marine Laboratory, University of Miami 



encountered in this manner in Florida and the 

 West Indies. Others not yet taken in the Florida 

 catch but which are likely to occur rarely are 

 Palinurellus gundlachi gundlachi (Von Martens), 

 Palinustus truncatus (H. Milne Edwards), and 

 Justitia longimana longimana (H. Milne Edwards). 

 Species of the genus Scyllarides, belonging to a 

 related family, are taken occasionally in the 

 Gulf of Mexico. 



Sexual Characters. — Sexes may readily be dis- 

 inguished by the following characters. The 

 tips of the fifth pair of walking legs in the male 

 terminate in a single, simple claw similar to those 

 of the other legs. In the female, the fifth leg 

 terminates in a pair of projections which act as 

 pincers used for preening the eggs where they are 

 attached to the under surface of the tail. The 

 male also differs in the presence of swollen sexual 

 openings at the base of the last pair of walking 

 legs. The female openings are much smaller and 

 are at the base of the third pair of legs. A further 

 distinction lies in the swimming legs. In the males 

 these end in a single, leaflike joint, whereas, in 

 the female, they are branched. In the first two 

 pairs these branches are leaflike, while in the 

 following legs the inner branch is a rod-like joint 

 to which the eggs become attached. 



Habitat. — The spiny lobster is most active at 

 night when it moves about in search of food. 

 During the daytime, it is usually hidden under 

 rocks, sea grasses, sea fans, large sponges, or other 

 marine growth, with only the whips projecting. 

 There is also a tendency to avoid very strong cur- 

 rents and muddy bottom. Grassy bars with 

 rocky heads and an abundant supply of small 

 shell creatures and worms, especially if protected 

 from excessive wave action, are likely places to 

 find new lobster grounds. While they are usually 

 caught in less than 30 feet of water, it is definitely 

 known that spiny lobsters exist in much greater 

 depths where there is rocky bottom. Movement 

 is usually carried out by walking forward on the 



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