656 



Fishery Bulletin 89(4), 1991 



Figure 1 



The study area with sampling grid for the 

 school shark Galeorhinus galeus, during 

 9-30 August 1983 (depths < 100 m) and 

 17 July-17 September 1986 (depths of 

 100-500 m) off Brazil. Surface area of 

 circles indicates catch rates in kg/hour 

 bottom trawling, and crosses indicate 

 zero catches. 



weight was measured, as recom- 

 mended by Mellinger (1966), for study 

 of certain aspects of reproduction. The 

 gonad weight included that of the 

 epigonal organ cut in front of the 

 rectal gland. Epigonal organ weights 

 were also measured in 43 specimens. 

 In males, the length of the clasper was 

 measured from the posterior origin of 

 the pelvic fin. For females, the follow- 

 ing data were recorded: diameter and 

 color of the largest ovarian follicle, 

 width of the nidamentary gland, pres- 

 ence or absence of embryos and uter- 

 ine eggs, weight of the full gravid 

 uterus, and greatest width of the non- 

 gravid uterus. Embryos were mea- 

 sured, sexed, and weighed with and 

 without the yolksac. Fecundity was 

 determined by counting maturing 

 ovarian follicles ("ovarian fecundity") 

 and uterine eggs and embryos ("uter- 

 ine fecundity"). Hepatosomatic and 

 gonadosomatic indices were calcu- 

 lated, using the weight of the organs 

 as a percent of the eviscerated body 

 weight. The latter indices were ob- 

 tained using the linear regression 

 equation of eviscerated weight as a 

 function of total length. Separate 

 equations were used for sexually im- 

 mature sharks of both sexes, adult 

 males, and adult females (Table 1). 



Histological smears of the reproduc- 

 tive organs were obtained from 7 

 males and 17 females, ranging from 

 124 to 148cm TL. Testes smears were 

 made from cross-section surfaces on 

 glass slides. The nidamentary gland was opened length- 

 wise and smears were made of the surface of its lumen 

 on glass slides. Smears were also made of the contents 

 of the epididymis and the seminal vesicle. Smears were 



fixed in a solution of equal proportions of ethanol and 

 ethyl ether and stained with haematoxylin-eosin. 



The present study follows Compagno (1988) with 

 respect to nomenclature. 



