each juvenile was transferred to a separate aquarium 

 containing 1.5 1 of seawater. 



Crabs in the group held at 15°C were maintained in 

 clear plastic boxes measuring 27X15X5 cm. Each 

 box consisted of 18 chambers (each 4.5 X 5 X 5 cm). 

 Crabs were maintained in individual chambers for 

 the duration of the study. 



In all cases, survival and molting were checked dai- 

 ly, and the red crabs were transferred weekly to clean 

 culture vessels with clean seawater. Carapace width 

 was measured with calipers after each molt. 

 Measurements were taken at the widest dimensions 

 of the carapace. 



Results and Discussion 



Our data show a linear relationship between car- 

 apace width and time over at least the first five post- 

 larval molts (Fig. 1). This differs from results of some 



other studies of growth in crustaceans in which 

 increase in carapace width was a logarithmic function 

 of time (for review see Hewett 1974). However, 

 Tagatz (1968) and Simpson (1961) have reported 

 linear increases in carapace width in captive 

 crustaceans. 



We recognize that the growth rates determined in 

 the present investigation may be biased by labo- 

 ratory conditions (diet, substrate, and pressure dif- 

 fered from natural conditions) and, further, that the 

 small sample size at 6°, 9°, and 12°C requires cau- 

 tious interpretation of results. Nevertheless, we have 

 shown that growth occurs very slowly at 6°C, a tem- 

 perature characteristic of depths >500 m (Haefner 

 1978). Between 9° and 15°C, however, growth is 

 five to six times more rapid than at 6°C. The relative 

 independence of growth from temperature in the 9°- 

 15°C range suggests that this is an optimal range for 

 juvenile existence. These conclusions suggest that if 



Fic.URE 1. — Least-squares regression lines de- 

 scribing rate of increase in carapace width of 

 juvenile red crabs, Geryon quinquedens. CW = 

 carapace width; D = days postmetamorphosis. 

 Numbers in parentheses adjacent to data points 

 indicate number of crabs measured in calculat- 

 ing carapace width. 



100 200 300 



MEAN DAY OF MOLTING 



400 



904 



