The reproductive biology of Nautilus pompilius in the Philippines

Records of Nautilus pompilius trapped in the Tañon Strait, Negros Oriental, Philippines were kept for a 1 year period from August 1971 through August 1972, and ovaries of mature females collected from August 1971 through March 1972. Females averaged only 8% of the catch during the year of study, but were more abundant in catches from January through May. The male:female ratio was not markedly altered at any depth in the trapping range (61 to 300 m). During the 8 month period, there was no trend apparent in the changes in average size of the ovaries collected; however, oocytes within varied markedly in their maximum weight. Encapsulated spermatophores are stored above the buccal cone on the male, and are attached unencapsulated below the ventral cirri of the female. N. pompilius pairs kept at 80 m remained healthy but laid no eggs from September 1971 through May 1972.