GULF OF MEXICO 



465 



Although these are msufficient experimental 

 data to draw any definite conclusions, the observa- 

 tions of fishermen upheld general observations 

 regarding seasonal movements associated with 

 breeding habits. (Dawson and Idyll, 1951.) 



During the months of February to April, the 

 lobsters tend to collect in certain inshore areas 

 while mating. Duruag April to June, the females 

 move into deeper water where the eggs are laid 

 and return again during July and August. Spiny 

 lobsters also tend to move offshore during the 

 cold months of December and January. There is 

 reason to believe, however, that spiny lobsters are 

 present at all times of the year in deeper water 

 wherever there is protection in the form of rocky 

 heads or marine growth. 



Molting. — At intervals, the spiny lobster casts 

 its shell and grows a new one. Molting is evident 

 in some lobsters at all times of the year. Observa- 

 tions made in the Bahamas show that the majority 

 of males and young females are foimd molting 

 during the months of April to June and again 

 during October to December. The mature females 

 molt during early spring before the start of the 

 breedmg cycle, and sometimes during August 

 after they have shed their eggs. Only the smaller, 

 immature females molt diu-ing June. Molting 

 probably takes place following periods of abundant 

 food supply and is partially dependent upon 

 temperature. 



Prior to molting, the spiny lobster seeks the 

 shelter of rocks and ceases to feed actively. For 

 this reason, the number of molting individuals in 

 the ordinary type of trap does not truly indicate 

 the percentage undergoing molt. After a period 

 varying from a few hours to a few days, the old 

 shell cracks along definite lines and becomes dis- 



lodged first from the cape region and then from 

 the tail. The new shell is in place beneath the old 

 one before molting, but it does not harden com- 

 pletely for at least a week. 



Immediately after losing the old shell, the 

 lobster has been found to absorb considerable 

 quantities of water. This accounts for the rapid 

 increase in size prior to hardening of the new 

 shell. From the time when cracks first begin to 

 appear in the old shell until the new shell no 

 longer feels soft when compressed in the hand, 

 molting takes a little more than 2 weeks. 



Growth Rate. — Studies of growth rate have been 

 based upon the direct measurement of captive 

 individuals, length frequency analyses of the 

 catch, and by a comparison of molting frequency 

 with growth between molts. Although none of 

 these methods have given conclusive results, they 

 indicate that growth of the spiny lobster when 

 about 1 pound in weight is somewhat greater 

 than 1 inch per year. 



LITERATURE CITED 



Dawson, Charles E., Jr., and Idyll, Clarence P. 

 1951. Investigations on the Florida spiny lobster, 

 Panulirus argus Latreille. Florida State Board of 

 Conservation Tech. Ser. No. 2, Univ. of Miami. 

 Lewis, John B. 



1951. The phyllosoma larvae of the spiny lobster. Bull. 

 Mar. Sci. Gulf and Caribbean 1 (2) : 89-103. 

 Smith, F. G. Walton. 



1951. Caribbean spiny lobster investigations. Proc. 

 Gulf and Caribbean Fish. Inst., 1950. Univ. of 

 Miami. 

 Von Bonde, Cecil, and Marchand, J. M. 



1935. The natural history and utilization of the Cape 

 crawfish, Kreef, or spiny lobster. Fishery Bull. No. 1, 

 Dept. Commerce and Industries, Fish and Mar. 

 Biol. Survey Div., Union of South Africa. 



