Abstract

This study aimed to elucidate gonadal development and the reproductive cycle of Heminerita japonica inhabiting the intertidal zone of Geomundo, Jeollanam-do, Korea. From April 2013 to March 2014, the condition index (CI), gonadosomatic index (GSI), and gonadal development were examined histologically, and monthly variations in water temperature and salinity were recorded. Water temperature ranged from 10.7 to 24.6 °C, with the highest value in August 2013 and the lowest in March 2014. Salinity ranged from 31.1 to 34.4 psu, with the lowest value in August 2013 and the highest in February 2014. Monthly CI patterns were similar between females and males, peaking in November (female: 43.87 ± 4.07; male: 44.49 ± 3.53) and reaching minima in June (female: 23.77 ± 6.07; male: 23.18 ± 6.08), indicating regular seasonal periodicity. Based on histological observations, the reproductive cycle was classified into five stages: early development (October-February), late development (November-April), ripe (February-May; females February-May and males March-May), partially spawning (May-July), and degenerative/resting (June-October; females July-October and males June-October). These findings provide baseline information for the conservation and ecological study of H. japonica.