진해만에 서식하는 피조개 (Anadara broughtonii )의 월별 생식소 발달 및 에너지 저장 물질 변화

초록

The blood clam (Anadara broughtonii) has experienced a dramatic decline in production in Korea, decreasing from approximately 58,000 tons in the mid-1980s to 1,714 tons by 2009, representing a 97% reduction. To understand the reproductive ecology and physiological status of A. broughtonii and provide baseline data for industry revitalization, we investigated the seasonal changes in gonadal development, condition index (CI), and glycogen content of A. broughtonii collected from Jinhae Bay, southern coast of Korea, from February to December 2019. Monthly clams (n = 30 per month) were analyzed using histological examination to determine the stages of gonadal development and energy reserve dynamics. Environmental parameters, including water temperature, salinity, and chlorophyll a, were monitored simultaneously. Our results revealed distinct seasonal patterns: gonadal development progressed from an indifferent stage in winter (February-March) through early development (April), late development (May), and ripe (June) to active spawning (June-September) and spent stages (September-October), with a return to the indifferent stage by December. Females showed approximately one month earlier developmental progression compared to males. The condition index reached its maximum value of 38.4 ± 1.5 in June and declined to a minimum of 18.6 ± 1.1 by September, reflecting energy expenditure during spawning. Glycogen content in somatic tissue showed a similar pattern, peaking at 19.5 ± 1.2 mg/g DTW in April and declining to a minimum of 3.3 ± 0.4 mg/g DTW in September. The synchronized changes in gonadal development stages, condition index, and glycogen content indicate that A. broughtonii adopt a concentrated summer spawning strategy with energy allocation primarily directed toward reproduction. Notably, the spawning timing coincided with the peak of chlorophyll a, suggesting that the reproductive strategy is synchronized with food availability to maximize offspring survival. These findings provide essential baseline data for understanding the reproductive characteristics of A. broughtonii in Korean waters and offer insight into the physiological basis of the species' population dynamics. The data will support the development of effective management strategies for A. broughtonii aquaculture and contribute to industry recovery efforts.

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