## 1 Introduction  
Zooplankton provides important trophic links in aquatic and marine trophic webs by transferring energy and materials from microbes to higher trophic levels [1]. Zooplankters are the main natural food source of larval and juvenile fishes worldwide [2]. Zooplankters are valuable indicators of ecological conditions due to their intermediate position, linking primary production with consumers at higher levels of the trophic cascade, and being sensitive to environmental characteristics [1, 3, 4]. Zooplankters are sensitive to changing physical and chemical properties of waters. These abiotic parameters affect the spatial distribution and abundance of zooplankton [5, 6, 7]. As such, environmental changes could also affect the geographic distribution of certain species [3, 8]. At the same time, some opportunistic species could adapt to particular environmental changes [9]. The copepod assemblage is the most dominant group of the zooplankton community and is considered as a key group in the marine pelagic environment [10]. The copep genus _Temora_ belongs to the family Temoridae with broadcast-spawning representatives. It is planktonic and important as it provides one of the major groups of prey for commercially shoaling fishes [11]. To date, a total of six species belong to the genus _Temora_ worldwide. According to historical records, four species of _Temora_ have been reported in waters around Taiwan [12; 13; 14; 15; 16; 17; 18; 19; 20; 21]. Among those, _Temora turbinata_ ([PERSON], 1849) and _Temora discaudata_ ([PERSON], 1889) were recorded in the waters of northern Taiwan [22]. _Temora turbinata_ has been recorded as the predominant species in mesozooplankton communities in various environments around the world, such as in Korea [23], in Taiwan [21], in Brazilian coastal waters [24], and in coastal and shelf waters [11], as well as tropical and subtropical areas in general [25; 26; 27; 28; 20]. This species is widely adapted to a variety of environments, such as polluted and eutrophicated waters, eutrophic lagoons, outfall areas, and nuclear power plant discharge areas [17; 20; 27; 29; 30; 31]. _T. turbinata_ could especially cooccur with the bloom-forming _Karenia brevis_ in the Gulf of Mexico, a toxic dinoflagellate [32]. The feeding behavior of _T. turbinata_ is opportunistic and omnivorous and depends on the food item composition in ambient waters. Previous reports found it primarily herbivous and rarely carnivorous [33]. In addition, _T. turbinata_ as a suspension feeder prefers microscopic and non- or slow-moving plankter, such as _Thalassisira_ spp. [34], and moving prey ciliates [35]. In dioecious species, the theoretical sex ratio is balanced (1:1, female:male), whereas biased sex ratios are quite common in nature [36; 37; 38]. The sex ratio represents an internal factor that affects population dynamics and growth [39; 40]. In marine copepods, sex determination and sex ratios are governed by diverse hydrological factors, such as pH, chemical composition, temperature, depth, and hydrostatic pressure, which commonly leads to an alteration of sex ratios and reproductive timing [41; 42; 43]. For example, the sex ratio of _Acartia tonsa_ increased from 0.3 \(\pm\) 0.1 to 1.3 \(\pm\) 0.1 with a decrease of salinity from 35 to 13 PSU in the laboratory [44]. Besides such abiotic factors, previous reports revealed that biotic factors, such as metabolism, reproductive age, and life span, also play important roles that affect the sex ratios of copepods [45; 46; 47]. The scarcity of data referring to in situ sex ratios is also due to the effect of differential vertical migration of sexes, and the difficulty of identifying sexes in immature copepites. Sex ratio is, therefore, probably the most understudied population trait in copep ecology [43]. A few studies reported developmental time, growth, length-weight relationship, chemical content, egg production rate, biomass, and temporal variation in the population production rate of _T. turbinata_ from different ocean areas [30; 48; 49; 50; 51; 52; 53; 54].