BIGFORD: EFFECT OF DIETS ON SPIDER CRAB LARVAE 



100 ~ 



starved (S) 



50 



\. 



\A 



Euplotes vannus , Dunaliella viridis 8* Eurytemora of finis ( E ED) 



D. viridis (D) 



ArtemJQ salina , Brochionus plicatilis , D. viridis , and 



Eurytenriora affinis (ABDE) 



~ ° ~ B plicotilis a D. viridis / A. soling , B. plicatilis , and 

 D viridis ( BD/ABD) 



\ VvA "■^■■- 1 



» ^'A "v/o °-v 1 -A- 8 plicatilis a D. viridis (BD) 



« \ V"-.; ol 



\ \\\ ~ ° ~ A solino , B plicatilis a D viridis (ABD) 



\ • 'S 



\ *• )J ~  ~ A_. sol ing (A|) 

 • \ \ \ V- V- A - A. solino (Ao) 



\\ ^ \ 'Tv 



\ 



 — ■— BCia— a 



8 



10 



AGE (days) 



Figure 2. Percent survival at each day for Libinia emarginata larvae reared on nine laboratory diets. Refer to Table 1 for 



concentrations and sizes of food organisms in each diet. 



Table 2. — Survival data and percentages to each stage of 

 Libinia emarginata on the diets permitting larval development 

 past stage I. A^i, Nn, andNn^ represent number of larvae surviv- 

 ing to each stage; Af^ equals initial number. 



on the carapace were absent in nearly all larvae 

 reared on diet D. 



Survival on diet EED (ciliate, copepod, and al- 

 gae) was only slightly higher than the starved 

 controls (Figure 2). No molts were observed. Mor- 

 tality was 100% by day 8. 



A diet of Brachionus and Dunaliella (BD) al- 

 lowed development into stage II. With this diet 

 36% (29/80) of the stage I zoeae molted into stage 

 II, but all died by day 11. 



Food organisms offered during stage I in diet 

 BD/ABD were identical to diet BD. Artemia nau- 

 plii were added for all ensuing stages. Survival 

 was 45% to stage II and 4% to both the megalopae 

 and juvenile stages. 



Diet ABD, identical to diet BD/ABD after stage 

 I, allowed 73% survival to stage II, 50% to the 

 megalopae, and 13% to the first crab stage. 



Higher survival to stage II was achieved by diet 

 ABDE, which included copepod subadults. On this 

 diet, 80% of the zoeae molted successfully into 

 stage II; 47% molted into megalopae. No larvae 

 metamorphosed into the crab stage although sev- 

 eral died during ecdysis. 



Two diets of newly hatched Artemia nauplii 

 were tested. Diet Ai, with 3 nauplii/ml, yielded 

 74% survival to stage II, 43% to megalopae, and 

 10% to the first stage crab. A second diet, Ag (6 

 nauplii/ml), yielded higher survivals to stage II 

 and megalopae, 83% and 75%, respectively, than 

 any other diet. Survival to the juvenile stage was 



61 



