FISHERY BULLETIN: VOL. 82, NO. 2 



the appearance of corresponding female products. 

 In Ostrea lurida, for example, spermatogonia are 

 proliferated first throughout the follicles, but be- 

 fore the sperm mature oogonia have developed into 

 numerous oocytes in the same follicles and the 

 gonad has a definite intersexual character (Coe 

 1932). More than 90 c /c of the young oysters exhibit 

 the bisexual condition and no strictly male or 

 female specimens occur. Old oysters in the female 

 phase retain sperm balls and spermatogonia, and 

 those in the male phase retain large and small 

 oogonia. The two anomalous ocean quahogs found 

 by Mann (1982) were examples of bilateral her- 

 maphroditism, i.e., the germinal cells for each sex 

 were in separate follicles. None of the inves- 

 tigators of the reproductive cycle in ocean quahogs 

 suggested finding ambisexual conditions 

 (Loosanoff 1953; von Oertzen 1972; Jones 1981; 

 Mann 1982 ). Thus, the characteristic germinal cell 

 development for protandry is lacking in ocean 

 quahogs. 



Sex reversal in some molluscs has been linked to 

 castration from parasites invading the gonads, but 

 evidence of causality was considered inconclusive 

 by Noble and Noble (1961) and Malek and Cheng 

 ( 1974 ). Except for the occurrence of the commensal 

 nemertean, Malacobdella grossa, in ocean 

 quahogs (Gibson 1967; Jones 1979), parasites in 

 the species have not been reported (Ropes and 

 Lang 1975 ) 4 . The causality of hermaphroditism in 

 ocean quahogs, then, remains uncertain and evi- 

 dence is unavailable that sex may be environmen- 

 tally determined. 



The hypothesis that female ocean quahogs 

 may live longer than males has some support from 

 determinations of the sex of specimens recovered 

 from the marking site in August 1980. Based on 

 predicted ages of ocean quahogs at the marking 

 site reported by Murawski et al. ( 1982 ), the largest 

 and oldest notched ocean quahogs were predomi- 

 nantly female. Since this may be atypical for the 

 extensive population of ocean quahogs inhabiting 

 the Middle Atlantic Bight, samples from other lo- 

 cations are being examined to determine possible 

 spatial variations. 



ACKNOWLEDGMENTS 



We gratefully acknowledge the technical assis- 



4 Ropes, J. W, and H. S. Lang. 1975. An annotated bibliog- 

 raphy of the ocean quahog, Arctica islandica (Lin- 

 naeus). Xeroxed manuscr., 67 p. Northeast Fisheries Center 

 Woods Hole Laboratory, National Marine Fisheries Service, 

 NOAA, Woods Hole, MA 02543. 



tance of Dorothy W. Howard and Cecelia S. Smith 

 of the Northeast Fisheries Center Oxford Labora- 

 tory, National Marine Fisheries Service, NOAA, 

 Oxford, Md., for histological preparations of 

 gonadal tissues; and Taina Honkalehto, Frances 

 Lefcort, and Miranda Olshansky, student trainees 

 from Smith College, Northampton, Mass., for as- 

 sistance in preparing acetate peels of the shells of 

 ocean quahogs. 



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