ABSTRACT

This study correlated the abundance of five jellyfish species in the south-west coast of India, South-eastern Arabian Sea, Crambionella orsini, Lychnorhiza malayensis, Chrysaora caliparea, Netrostoma coerulescens and Cyanea nozakii, with hydrographic parameters. Partial least square (PLS) analysis suggested strong correlations between jellyfish abundance and phosphate, silicate and chlorophyll-a content in water and showed a significant positive relationship with the first PLS component, while pH and sea surface temperature showed a significant negative correlation with the first PLS component, indicating that the abundance of four species, C. caliparea, C. nozakii, L. malayensis and N. coerulescens, increases with phosphate, silicate and chlorophyll-a content and decreases with pH and sea surface temperature. In contrast, the abundance of C. orsini increased with an increase in sea surface salinity and decreased with an increase in dissolved oxygen; except for this species, the abundance of jellyfish in the South-eastern Arabian Sea was positively affected by phosphate content of the water. The continuous decline in abundance of jellyfish from 2016 to 2019 in the south-west coast of India could be due to the influence of regional environmental changes or due to the specific ecological strategies of the jellyfish species in the upwelling zone subjected to high fishing pressure.

摘要

该研究将印度西南海岸、阿拉伯海东南部、Crambionella orsini、Lychnorhiza malayensis、Chrysaora caliparea、Netrostoma coerulescens和Cyanea nozakii的五种水母的丰度与水文参数相关联。偏最小二乘 (PLS) 分析表明水母丰度与水中磷酸盐、硅酸盐和叶绿素a含量之间存在很强的相关性，并与第一 PLS 成分呈显着正相关，而 pH 值和海面温度与第一成分呈显着负相关。 PLS 分量，表明C. caliparea、C. nozakii四个物种的丰度, L. malayensis和N. coerulescens , 随着磷酸盐、硅酸盐和叶绿素a含量的增加而增加，并随着 pH 值和海面温度而降低。相反，C. orsini的丰度随着海面盐度的增加而增加，随着溶解氧的增加而减少；除了这个物种，阿拉伯海东南部的水母丰度受到水中磷酸盐含量的积极影响。2016-2019年印度西南海岸水母丰度持续下降，可能是受区域环境变化的影响，也可能是由于上升流区水母物种的特定生态策略受到较高的捕捞压力。