84 
Fishery Bulletin 95 ( 1 ), 1997 
by estimating the distribution of spawning using both 
a classification scheme that considers these individu- 
als as reproductively active, and the classification 
developed herein, with subsequent testing by com- 
parison of these distributions to other measures of 
spawning activity, such as distributions of larval fish 
or of male:female ratios. 
Given the interval estimate for OV, and taking a 
conservative approach with respect to including in- 
dividuals that are not reproductively active in esti- 
mates of the spatial and temporal distributions of 
spawning, we recommend that researchers requir- 
ing an estimate of the reproductive status of female 
swordfish adopt a method that classifies reproduc- 
tively active female swordfish as those for which GI 
= ln(GW)/ln(EFL) > 1.375, the upper limit of the in- 
terval. When additional information becomes avail- 
able, further analyses should be undertaken. 
The need to develop species-specific classification 
methodologies has been clearly documented (de 
Vlaming et al., 1982). However, methods for species 
with similar characteristics and reproductive habits 
may be similar (Cayre and Laloe, 1986). Merrett 
(1970) found that for sailfish ( Istiophorus platy- 
pterus)', striped ( Tetrapturus audax), blue (T. 
nigricans), and black ( T. indica) marlin; and spearfish 
(T. angustirostris), changes in ovaries through 
oogenic cycles were similar in all species, as was the 
shape of the gonads (with the exception of the shape 
of the spearfish gonad, which was Y-shaped rather 
than bilaterally symmetrical). These changes are 
similar to those observed in swordfish (cf. Taylor and 
Murphy, 1992). Thus, while we concur with de Vlaming 
et al. (1982) and strongly recommend that classifica- 
tion methods be developed and validated for each spe- 
cies of billfish, we would speculate that results for these 
species would be comparable to those shown herein. 
Acknowledgments 
We thank Kurt M. Schaefer and George M. Watters 
for their helpful discussions of various aspects of this 
manuscript during its development. We also thank 
William H. Bayliff and Richard B. Deriso for review- 
ing this manuscript and for their useful suggestions 
for its improvement. Helpful remarks were also re- 
ceived from three anonymous reviewers. 
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