322 



Fishery Bulletin 102(2) 



/ 



*.. 



• • T* . I* •• • * 



0.3 0.4 



0.5 



— i 1 1 1 — 



0.6 0.7 0.8 0.9 



1.C 



Mantle condition index (mg/mm 2 ) 



3000 1- 

 2000- 

 1000- 







-1000 



-2000 



• • • V * • • . . 



L * J " ^ — ^ * * a wm ^ M • •  







0.0006 r 



>. 0.0004 - 



0.0002 



~1 r 



2 



1 1 1 r 



6 8 



Gonad weight (g) 



10 



- 1 1 1 



12 14 



0.0b 



-2000 



-1000 



1000 



2000 



3000 



Residuals 



Figure 13 



Residual plots of number of oocytes and ova from the equation 

 E YD = 378.28e (2 33C + 2447 °-° 24CGl (Eq. 18) where standing stock of oocytes and 

 ova (E YD ) are predicted from mantle condition index ( C) and gonad weight (G ). 

 Bottom panel shows probability density of residuals. 



normal part of ovarian maturation in L. oplaescens, as it 

 is the case for L. v. reynaudii (Melo and Sauer, 1998). Our 

 evidence for this is that the standing stock of oocytes in 

 immature female L. opalescens declines sharply as their 

 ovaries mature (D increases, Fig. 7B). Clearly a narrow 

 window of opportunity exists for an unbiased estimate 

 of the potential fecundity of L. oplaescens. If the count 

 is made too early in the ovarian maturation process, the 

 count will either be low because extensive primary oogo- 

 nia production may be still be occurring (64-mm female, 

 Fig. 7A) or too high because additional oocytes will be 

 absorbed before the female reaches maturity. If the count 



is made too late, it will be impossible to find a female that 

 has not ovulated. Our selection criteria "presence of yolked 

 oocytes" (which roughly begins at a oocyte size of about 

 1.1 mm) filtered out the very high counts of oocytes associ- 

 ated with immature ovaries. 



From the practical standpoint, dealing with atretic 

 losses that may continue into the spawning period is much 

 less important for L. opalescens than for L. v. reynaudii 

 (Melo and Sauer, 1998; Sauer et al., 1999) or L. pealeii 

 (Maxwell and Hanlon, 2000). In these squid, where the 

 spawning period may last weeks or months, atresia may 

 seriously bias potential fecundity estimates. In the pres- 



