FISHERY BULLETIN: VOL. 79, NO. 3 



3 



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 O 



z 



UJ 



2 

 < 



MALE 



MAMJJASONDJ FM 



4 - 



< 

 > 



y 3 



z 



UJ 



O 

 O 



2 - 



S 

 < 

 O 1 



FEMALE 



Figure l. — Annual cycle of gametogenesis in Placopecten 

 magellanicus based on assessment of histological sections for 

 each sample date, March 1979-March 1980. Modal values of each 

 sample indicated by • for females and o for males. Bars = 

 ranges. Median values indicated by ® in cases where median 

 values differ from modal values. 



of the females {N = 11) from the 14 September 

 sample, resulting in a marked drop in modal rank. 

 Variability within the population was greatest at 

 this time since ripe, partially spawned, and spent 

 individuals were all present in the population. 

 By 5 November, virtually all deep-sea scallops 

 sampled were spawned out. In January, modal 

 values again rose. Gonial cells were distinguish- 

 able in the follicles and characteristic gonadal 

 coloration became evident, although a few indi- 

 viduals showed signs of still being only partially 

 spawned out. 



Body Component Indices 



Seasonal changes in mean body component 

 indices are plotted in Figure 2. GMI, DGI, 

 QAI, and CAT all varied significantly with time 

 (P<0.01; analysis of covariance: body component 

 index by sample date with scallop height as a 

 cofactor). Similar analyses using raw tissue wet 

 weights also point out significant changes be- 

 tween sampling dates (P <0.01). Since differences 

 between the sexes were not significant for any of 



^ .075 

 % .055 



X .035 



UJ 



O 



Z 015 



MAMJJASONDJ FM 



DIGESTIVE GLAND 



.280 



< .240 



> 



X 



UJ 



O .200 



.160 



MAMJ J AS OND J FM 



QUICK ADDUCTOR MUSCLE 



< .050 



> 



.030 



X 



S 010 



z 



MAMJ J ASON DJ FM 



CATCH ADDUCTOR MUSCLE 



MAMJ J AS ONDJ FM 



Figure 2. — Seasonal fluctuations in soft-body component 

 indices for Placopecten magellanicus, March 1979-March 1980. 

 Bars represent 95% confidence intervals; • = female; o = male; 

 horizontal lines underscore samples which are not significantly 

 different at the 95'7f confidence level (male and female data 

 combined for each sample, least significant difference multiple 

 range test). 



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