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Fishery Bulletin 9 1 [2). 1993 



each year, and although 1989 July values were slightly 

 lower than the other months, the July 1988 values 

 were not. The observed changes in relative gonad 

 weight can thus be considered unbiased by individual 

 size. 



Nidamental gland and hectocotylus lengths Nida- 

 mental gland length was perhaps the most useful mea- 

 surement in female squids for obtaining an index of 

 maturity. The relationship of nidamental gland length 

 to mantle length and age of female specimens of 

 L. chinensis ( Fig. 5 ) closely resembled the ovary weight/ 

 age and mantle length relationships for this species 

 (Fig. 1B,D). For example, two separate relationships 

 were apparent when nidamental gland length was 

 plotted against age, whereas both seasons' data points 

 produced one curvilinear relationship for nidamental 

 gland length vs. mantle length. As with the ovary data, 

 these data suggest that nidamental gland length was 

 more closely related to mantle length than to age. 



Similarly for males, hectocotylus length vs. mantle 

 length and age (Fig. 6) exhibited the same pattern ob- 

 served in the testis weight/age and mantle length rela- 

 tionships (Fig. 1A,C). For example, in winter there was 

 a shift along the age axis, producing a separate correla- 

 tion for the summer hectocotylus length/age data. How- 

 ever, there was some indication that at large sizes, faster- 

 growing (summer) males had a shorter hectocotylus than 

 slower-growing (winter) males. This relationship was 

 similar to the testis weight/mantle length relationships 

 for /. pygmaeus ( Fig. 70, D) seen below. 



Idiosepius pygmaeus 



Gonad growth with age In contrast to L. chinensis, 

 within-season variability in maturity and age-specific 



trends for /. pygmaeus could be determined with a 

 greater degree of accuracy. This was possible because 

 of the greater number of replicate sub-amples taken 

 during each seasonal period (see Methods). 



The seasonal pattern of gonad growth was different 

 for /. pygmaeus than for L. chinensis. The seasonal 

 influence on gonad growth and maturation may have 

 been somewhat less for individuals of/, pygmaeus (ana- 

 lyzed for spring and autumn) compared with individu- 

 als of L. chinensis (analyzed for summer and winter). 

 However, individuals captured in autumn would have 

 grown over the warmer period at the end of summer, 

 while individuals from the spring sample would have 

 grown and matured through the colder period, at the 

 end of winter. 



Due to the considerable scatter in age/length rela- 

 tionships for this species (Jackson & Choat 1992), there 

 was also considerable scatter in the gonad weight/age 

 relationship (Fig.7A,B). While gonad weight/age rela- 

 tionships for L. chinensis resulted in different scatter 

 plots separated on the age continuum (x axis), the 

 pattern was modified differently for /. pygmaeus for 



