Annual Reproductive Cycle and Spawning Behavior of Chameleon Goby, Tridentiger Trigonocephalus in Korea

Abstract

Introduction: Gobiid fish are appropriate species for investigating the effects of endocrine disrupting chemicals with their small size, easy to handle, and strong tolerance [1]. Chameleon goby, Tridentiger trigonocephalus is distributed in mud flat, brackish waters of western and southern Korea, China and Japan [2]. At present, there is very little knowledge about its reproductive characteristics. In this study, we investigated the annual reproductive cycle and spawning behavior of chameleon goby. Methods: In the field investigation, fishes were sampled monthly from the seagrass bed of Dongdae Bay (southern coastal waters of Korea) between April 2009 and March 2010. Gonadosomatic index (GSI) was recorded and gonads were removed and fixed in Bouin’s solution and processed for light microscopy. For observation of spawning process from indoor tank, sexually mature fish were held under an artificial light and temperature regime. Fertilized eggs and guarding male were transferred to incubation tanks until hatching. Results: GSI of females increased from April and peaked in May (16.31±2.16), then decreased from June and were the lowest value in August (0.34±0.0). GSI of males increased from April and peaked in July (1.17±0.35), then decreased dramatically in August (Fig. 1). In histological observation, the annual reproductive cycle can be divided into four successive stages in females: the growing (November-March), maturing (April-May), ripe and spawning (June-July), and recovery (AugustOctober) stages. Males passed through growing (November-March), maturing (April-June), ripe and