수온 변화가 Acartia steueri의 부화 속도와 생산력에 미치는 영향

Abstract

Copepods are important food resources for larval fish. Changes of sea water temperature driven by season and climate change may affect on the survival of copepods. Temperature affects on the rate of egg production and embryonic development of copepods, further population variations. Population variations of Acartiidae was investigated based on weekly collected samples from the Dadaepo beach, Busan Korea from August in 2015 to April in 2016. Live copepods were also reared in the laboratory at five temperature regimes (10, 14, 18, 22 and 26℃) to test temperature effects on egg production rate and embryonic development rates of A. steueri. Egg production rates were significantly correlated with temperature. Average egg production of A. steueri ranged from 8.8 to 35.0 eggs female-1 d-1. The mean of egg production increased with temperature from 10 to 22℃ but then decreased with further increase at 26℃. The embryonic development time of A. steueri was longest at 10℃ and shortest at 22℃. Optimal temperature for hatching success rates of A. steueri was between 18℃ and 22℃. Total five Acartiid species appeared in the study area: Acartia omorii, A. steueri, A. pacifica, A. erythraea, A. sinjiensis. A. steueri and A. omorii dominated in colder season from January to April in 2016 while A. pacifica, A. erythraea and A. sinjiensis dominated during warmer month from August in 2015 and then decreased to December in 2016. This study indicates that embryonic development rate can estimate temperature-dependent generation time and their population variation, which may affect the larval survival of fishery target species.