500 



Fishery Bulletin 98(3) 



in swordfish (Taylor and Murphy, 1992; Arocha and Lee, 

 1995; our study). Gonad weights scaled for body length 

 (because body lengths, not weights, are typically collected 

 for swordfish at sea) deserve further evaluation as predic- 

 tors of spawning readiness, particularly because our find- 

 ings for swordfish in the central North Pacific are so similar 

 to those of Hinton et al. (1997) for Atlantic swordfish. 



Other maturity estimates Prior reported estimates of body 

 size at sexual maturity for female swordfish in the Pacific 

 in general do not agree with ours, but dissimilarities likely 

 reflect the different measures used to gauge sexual maturity 

 used by various researchers. For example, Yabe et al. ( 1959) 

 concluded, from length distributions and gonad weights, 

 that "most I female] swordfish" in the western Pacific mature 

 sexually between 150 and 170 cm EFL. Kume and Joseph 

 (1969) observed that female swordfish "in spawning condi- 

 tion" (defined as having a greater than defined threshold 

 value of gonad index) were not "regularly encountered" until 

 about 170 cm EFL. Sosa-Nishizaki's ( 1990, p. 64) estimate 

 of sexual maturity at about 160 cm EFL for "most individu- 

 als" was also inferred from a length-based GI. In contrast to 



females, ours is the first estimate of any kind for body size 

 at sexual maturity of male swordfish in the Pacific Ocean. 

 Our results overall underscore the importance of sex-spe- 

 cific, histologically validated estimates of median body size 

 at sexual maturity as data for stock assessments. 



Our estimates of L-,, for swordfish caught by the Hawaii- 

 based longline fishery appear comparable (for males) to 

 slightly smaller (females) than estimates for swordfish 

 caught in several regions of the Atlantic. For swordfish 

 from the Straits of Florida, Taylor and Murphy (1992) 

 observed L,-,|'s of 112 and 182 cm lower jaw-to-fork length 

 (LJFL) for males and females, respectively, equivalent to 

 96 and 161 cm EFL. Arocha and Lee (1996) estimated 

 Ljg's of 129 (males) and 179 cm LJFL (females), equiva- 

 lent to 112 and 158 cm EFL, respectively, for swordfish 

 caught throughout the western Atlantic. We caution that 

 these LgQ estimates for swordfish in the Atlantic may not 

 he totally comparable to ours because studies might differ 

 in whether estimates apply to fish caught throughout the 

 entire year or during spawning periods only. 



Female swordfish in the MediteiTanean presently mature 

 at an L^^ of about 142 cm LJF'L (de la Serna et al., 1996), 



