| A preliminary field study was carried out in Panama Bay, Panama. This study showed an inverse correlation between mean oocyte diameter of Argopecten circularis (Sowerby, 1835) and seawater temperature, but no correlation between oocyte diameter and phytoplankton density.;The laboratory study showed that A. circularis increased significantly in total weight by 30 days in high phytoplankton densities. Gonadal dry weight increased significantly after 40 days at high food ration, but gonadal index (dry weight of gonad/dry weight of whole animal x 100) declined.;The gonadal index of 8- and 16-month old scallops declined through the first 40 days of the experiment. Also, carbohydrate content declined scientifically in the digestive gland and adductor muscle. This suggests energy was used either on somatic tissue and/or reproduction. Some carbohydrates could have been used for reproduction, but were not transferred directly to the gonad before day 40.;Adductor muscle dry weight and protein content of 8- and 16-month old scallops increased by the first 40 days of the experiment, then declined around day 55. Simultaneously, around day 55, both groups of scallops increased noticeably in gonadal dry weight and protein content. This suggests the adductor muscle stores protein during the first 40 days, then protein catabolism in the adductor muscle contributes to the reproductive activity of the gonad.;These laboratory studies suggest that gametogenesis in A. circularis is developed primarily during the wet season at low phytoplankton densities, and somatic growth (especially of the adductor muscle) is enhanced during either dry or wet seasons at high phytoplankton densities. The laboratory study in Delaware suggests that one-year-old scallops will spawn in the field in March. |
