Copepod egg production in surface waters (0-100 m) of the Aegean Sea in September 1997

Vertical tows of the WP-2 net (mouth diameter 57 cm, mesh size 200 µm) were carried out from 0 to 100 m. Towing speed was 0.3 m/s. Sample volume was estimated by the net mouth area and the towing distance. Egg production rates of dominant calanoid copepods were determined by incubation of fertilized females (eggs/female/day) collected in the 0-100 m layer. For estimating copepod production lengths of copepods and eggs were converted to body carbon (Hopcroft et al., 1998; doi:10.1007/s002270050281) and production was estimated from biomass and weight-specific egg production rates by assuming that the rates are representative for juvenile specific growth rates (Berggreen et al., 1988; doi:10.1007/bf02112126).

采用口径57 cm、网目尺寸200 µm的WP-2网开展0至100米水深的垂直拖网采样，拖曳速度为0.3 m/s。采样体积通过网口面积与拖曳距离计算得到。对采集自0~100米水层的优势哲水蚤目桡足类（calanoid copepods）的受精雌体进行孵化实验，测定其产卵率（单位：卵/雌体/日）。为估算桡足类生产量，先将桡足类个体及卵的体长转换为体碳含量（Hopcroft等，1998；doi:10.1007/s002270050281）；随后基于生物量与单位体重产卵率开展生产量估算，假设该产卵率可代表幼体的比生长速率（Berggreen等，1988；doi:10.1007/bf02112126）。