Table I. — Percent frequency of specimens in which the 

 left gonad was larger in weight than the right; left gonad 

 expressed as average percentage of combined gonad 

 weight and length. 



the right in both sexes. The left ovary of sailfish also 

 averaged larger but the left testis averaged smaller in 

 weight. Females exhibited the greatest gonadal 

 asymmetry and the difference in size between right 

 and left ovaries was often obvious without meas- 

 urement. Williams (1963) observed similar differ- 

 ences in Indian Ocean striped marlin with the left 

 gonad always larger in both length and displacement 

 volume. 



Several noteworthy gonadal abnormalities were 

 also seen. In ten striped marlin, five sailfish, and one 

 blue marlin, one ovary was lacking; in two striped 



marlin and one sailfish one testis was lacking. This 

 phenomenon can result from the fusion of the two 

 gonad primordia during development, or simply 

 from the failure of one gonad to develop (Hoar and 

 Randall, 1969). In one striped marlin the ovary had 

 proliferated into many different sized lobes filling 

 much of the coelomic cavity (Fig. 6). It was filled 

 with large eggs which were visibly misshapen. 

 Another striped marlin was noted to have a testis 

 which had divided into separate anterior and pos- 

 terior lobes. Four ovaries were tumorous, brown- 

 red in color, consisting of dense, odiferous tissue. 

 Penellid copepods were found encysted in the 

 gonads of three striped marlin and one sailfish. 



Measures of Sexual Maturity 



The general problem of finding an accurate and 

 efficient means of measuring sexual maturity in 

 fishes has resulted in the development of many tech- 

 niques. Testes have not been found to be suitable 

 because of problems encountered in measuring ac- 

 curately their sex products (June, 1953). In addition, 

 Merrett (1970) has shown by histological examina- 

 tion that unlike the case in most teleosts, there is 

 differential maturation of spermatozoa in the testicu- 

 lar lobules of billfishes. There is thus only a small 



Figure 6. — Illustration of an abnormal striped marlin ovary with different sized lobes 



throughout the coelomic cavity. 



92 



