Seasonal Population Structure of the Copepod Temora turbinata (Dana, 1849) in the Kuroshio Current Edge, Southeastern East China Sea

Abstract

The abundance of adult males, females, and copepodites, and sex ratio of a Temora turbinata population and seawater hydrology were studied from 2018 to 2019 in waters off northeast Taiwan, northwest Pacific Ocean. The hydrological parameters showed significant differences between sampling months caused by interactions of Kuroshio, East China Sea water, and the China Coastal Current. The highest average abundance was recorded from the June 2018 cruise with 2903.92 ± 3499.47 (inds. m−3), followed by a cruise in June 2019 with an average abundance of 1990.64 ± 1401.55 (inds. m−3). The sex ratio ranged between 0.25 and 2.33; the records were significantly higher in samples of June 2018 than during other sampling cruises (one-way ANOVA). The spatiotemporal distribution of T. turbinata showed a clear pattern of seasonal changes among sampling stations and distribution zones. Abundance of females and copepodites correlated significantly positive (r = 0.755, p < 0.001), whereas sex ratio (r = 0.247, p = 0.119) did not correlate significantly. The present study revealed that the abundance of T. turbinate was highest in June and was positively correlated with seawater temperature; furthermore, this is the first time the in situ sex ratio of T. turbinata in western Pacific waters has been reported.

Copepods as Indicators of Different Water Masses during the Northeast Monsoon Prevailing Period in the Northeast Taiwan

“…Due to the short life span characteristics, the abundance of copepodites commonly accounts for 21–47% of the total zooplankton abundance and 59.77% to 90.82% of the total copepod abundance in field campaigns [ 78 , 79 , 80 ]. In the present study area, Wang et al reported that the copepodites of the dominant species T. turbinata accounted for 27.29% to 60.30% of the total Temora abundance throughout the year [ 56 ]. In the present study, calanoid copepodites represented the most dominant group, which accounted for 28.06% of the total average copepod abundance with an OR of 100%.…”

“…Stations around Keelung Island were controlled by northeast monsoon-derived water masses characterized by the following indicator species: T. turbinata , C. elliptica , and C. pauper . The meso-epipelagic T. turbinata , which was the dominant species in the research area, is considered an indicator species of warm water masses and is widely distributed in tropical, subtropical, and temperate areas [ 35 , 50 , 56 , 82 ]. Tseng et al [ 82 ] demonstrated that C. elliptica significantly and negatively correlated with seawater temperature.…”

“…Previous studies indicated that seasonal successions of dominant copepod species range from 25.0% to 61.9% in northeast Taiwan, with, among others, the following dominant species Cosmocalanus darwinii , Canthocalanus pauper , Clausocalanus furcatus , Paracalanus aculeatus and Temora trubinata [ 8 , 12 , 52 , 53 , 55 ]. The dominant species, T. turbinata, shows a significant negative correlation with surface water temperature and seasonal variation in the research area [ 51 , 56 ].…”

“…Previous studies indicate that the planktonic copepods in the waters of northeastern Taiwan are affected by the interactions between East China Sea waters and Kuroshio waters [ 8 , 12 , 51 , 52 , 53 , 55 , 56 ]. The hydrological characteristics of the waters in this region change quite rapidly.…”

Research on the seasonal variation of zooplankton community in Daya Bay, South China Sea

“…Temora turbinata is regarded as the predominant species in mesozooplankton communities in various environments around the world. It is able to adapt to various habitats, such as eutrophic lagoons, polluted and eutrophicated waters, outfall areas, and nuclear power plant discharge areas (Hsu et al, 2008;Tseng et al, 2011;Wang et al, 2021). In particular, T. turbinate and Karenia brevis can co-occur in the Gulf of Mexico.…”