464 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



legs, but occasionally, by quickly bending the 

 tail, the animal will move backward rapidly to 

 avoid danger. 



Food and Enemies. — The spiny lobster has a 

 wide range of food and is frequently a scavenger. 

 Examination of the stomach shows small mol- 

 lusks, such as young conchs and pelecypods, 

 worms, and occasionally, small Crustacea. Sea- 

 weed is frequently found in the stomachs but may 

 not necessarily be of food value. Spiny lobsters 

 will also eat the fresh and dried meat of fish. 

 Food is usually detected by the lobster at some 

 distance by means of a chemical sense in the 

 whips. 



In the early stages of development, the spiny 

 lobsters are small, transparent creatures which 

 drift in the water. In these stages they are eaten 

 by a great variety of fish and plankters. After 

 they change into the adult form, but while thej^ 

 are quite small, they crawl among the rocks or 

 grass and are frequently eaten in large numbers 

 by groupers, snappers, and other bottom fish. 

 The older lobsters, even up to a large size, are 

 food for sharks, groupers, and jewfish. 



Breeding Habits and Life History. — At some time 

 between February and July, mating occurs at 

 which time the male extrudes a viscous fluid from 

 the swollen openings at the base of the last pair 

 of walking legs. This fluid becomes attached to 

 the under surface of the female between the last 

 three pairs of legs and rapidly hardens on the 

 outside to form a dirty-white or gray-black sub- 

 stance known as the sperm sac. 



A short time after the mating act, the females 

 lay their eggs, or berry, which become attached 

 to the paddles under the tail. The eggs are a 

 bright orange-red in color and about Vz^ inch in 

 diameter. They are fertihzed by spermatozoa 

 which the female releases from the still soft inside 

 of the sperm sac by scratching with the tips of 

 her legs. The number of eggs varies with the size 

 of the lobster. In the case of a 9-inch animal, 

 the nimiber is about 500,000 forming a berry-like 



mass. 



Most of the females migrate into deeper water 

 while the eggs are incubating and hatch them 

 during the summer months within 3 weeks after 

 laying. The majority of egg-bearing females are 

 found in April. Some females may mate later 

 than others and, as a result, a small number may 

 still be found with eggs as late as Noveinber. 



The old or spent sperm sac is also found in occa- 

 sional individuals during every month of the year. 

 Most females, however, have completed breeding 

 by the beginning of July. After releasing the 

 eggs, the females begin to return to shallower 

 water. 



A small number of females under 7 inches in 

 length, measured from the tip of the telson to a 

 point between the "horns," are found carrying 

 eggs. These have a cape length of under 2 inches 

 and a weight of under Vi pound. The majority, 

 however, do not appear to breed until they reach 

 a body length of 8 inches, corresponding to a cape 

 length of 2% inches and a weight of % pound 

 (Smith 1951). 



The egg of Panulirus argus hatches directly into 

 a phjdlosoma larva (Lewis 1951). This is a flat 

 leaflike planktonic form with long legs and prom- 

 inent stalked eyes. Eleven stages of development 

 are recognizable during the planktonic existence 

 which appears to last over a period of as much 

 as 6 months. The larvae grow from about 2 mm. 

 in length to about twice this size. During this 

 period they are carried considerable distances by 

 currents and are sometimes found in plankton 

 hauls taken in the open ocean. 



No information is available regarding the be- 

 havior of larvae of Panulirus argus. It is re- 

 ported, however, by Von Bonde and Marchand 

 (1935) that the early planktonic stages of the 

 South African species react to light so as to ap- 

 pear at the surface during nighttime and to retire 

 to deeper water during daylight hours. In the 

 Australian species the final stages before meta- 

 morphosis are found at the surface. 



Migrations. — As a result of tagging experiments 

 in the Bahamas and in Florida, it is known that 

 the spiny lobster is able to migrate over consid- 

 erable distances. Individuals have been recap- 

 tured as much as 100 miles from the point of 

 release after a lapse of a little more than 100 days. 



At all times of the year, lobsters may undergo 

 mass movements alongshore, apparently in rela- 

 tion to the food supply. They also tend to move 

 inshore immediately after stormy periods. At 

 times, offshore movements seem to be associated 

 with prolonged calm or warm weather, but mass 

 movemeats have also been observed with no 

 accompanying change in physical conditions. 

 These may also be related to a scarcity of food. 



