오륙도 인근 해역의 요각류 Paracalanus parvus의 월별 개체군 변동

Abstract

The population changes of the copepod Paracalanus parvus were investigated based on monthly collected samples. Zooplankton was collected using a cornical type net of 45 cm diameter with 330 µm mesh by vertical tows at four stations near Oryuk islets off Busan, South Korea from May 2013 to March 2014. Sex and developmental stages (CⅢ, CⅣ, CⅤ male, CⅤ female, adult male and female) of P. parvus were identified. Prosome length (PL) of P. parvus was measured. Abundance of P. parvus was the highest in February and the lowest in September. The abundance of adult female was highest, followed by female copepoditeⅤ throughout the experimental period. Mean PL decreased from May to August and then increased during colder months. The PL of P. parvus was negatively correlated with surface water temperature. The proportion of male copepodite Ⅴ stage was highest in June, and that of adult male was the highest in February. The proportion of male copepodite Ⅴ was positively correlated with surface water temperature. Monthly PL variations of P. parvus implied that size of P. parvus was negatively correlated with water temperatures. Monthly sex ratios of copepodite Ⅴ stage implied that propotion of male copepodite Ⅴ was positively correlated with water temperatures.