540 



Fishery Bulletin 94(3). 1996 



pealei. Color, however, is not a reliable means of sepa- 

 rating the species. Well-defined lines of chromato- 

 phores ("flame stripes") occur on the ventral surface 

 of the mantle in large males of L.plei; however, speci- 

 mens of L. pealei also may have a similar, though 

 less defined, color pattern. The mantle is long, slen- 

 der, and cylindrical in both L. pealei and L. plei, but 

 the posterior end of the mantle is more acutely 

 pointed in L. plei. Juvenile and subadult L. pealei 

 are more robust than L. plei of similar mantle length: 

 the head and eyes of the former species are moder- 

 ately large and the arms and tentacles are thick, 

 muscular, and long. The more robust character of L. 

 pealei is particularly evident when compared with 

 L. plei of the same mantle length. The fins are rhom- 

 boidal in shape in both species. 



Fin length as a percentage of mantle length is vari- 

 able in individuals of both species, but it is generally 

 greater in L. pealei than in L. plei in specimens of 

 similar mantle length (Table 3). Mean fin length in 

 relation to mantle length of L. pealei was 50% in the 

 size class 90.0 to 99.9 mm, and the mean ratio in- 

 creased as mantle length increased. However, fin 

 length to mantle length ratio of individual L. pealei 

 could be 50% in specimens as small as 70.0 mm ML; 

 the ratio of FL to ML was not consistently 50% or 

 greater until the individual mantle length reached 



110.0 mm. For L. plei, the ratio of fin length to mantle 

 length was less than 50% for individual squid smaller 

 than the 120.0 to 129.9 mm ML size class. Mean fin 

 length to mantle length did not exceed 50% until size 

 class 140.0 to 149.9 mm ML. 



Morphometric analyses 



Individual measurements were taken of 304 juve- 

 nile and subadult squids (L. pealei, ra=151; L. plei, 

 n = 153). All specimens were immature according to 

 the maturity classification scheme of Macy (1982). 

 The relationships between fin length and mantle 

 length, fin width and mantle length, and rachis width 

 and mantle length were best represented by the lin- 

 ear model. The relationships between weight, head 

 width, funnel cartilage length, nuchal cartilage 

 length, gladius width, arm length, and tentacle 

 length, with mantle length as the independent vari- 

 able, were best represented by the multiplicative 

 model. All indices were best represented by the lin- 

 ear model. 



Sexual dimorphism 



Loligo pealei Sex could be determined for only 36% 

 of the specimens identified as L. pealei (n=62). Males 



