Reproductive cycles of dominant calanoid copepods in the North Sea
نویسندگان
چکیده
The seasonal cycles of reproduction of the dominant copepods Acartia clausi, Temora longicornis, Centropages hamatus, C. typicus and Pseudocalanus spp. were studied at Helgoland Roads, southern North Sea. Egg production rate, clutch size, number of spawning females and prosome length were compared with temperature and phytoplankton concentration. Female A. clausi, T. longicornis and Pseudocalanus spp. were present all year round. T. longicornis and Pseudocalanus spp. bred continuously throughout the year, although egg production rates and the proportion of spawning females were low in winter. A. clausi did not spawn between the end of September and the end of January. Female C. hamatus were absent from the water column from November to May, and C. typicus from February to August. As the latter 3 species spawn year round in warmer regions, low temperature inhibition of reproduction is suggested for Helgoland, where winter temperatures are below 0°C. Maximum egg production was observed in all species, except the late-arriving C. typicus, in April/May, when females were largest. Significant correlations were only obtained between clutch size or egg production rate and prosome length, which in turn was correlated with temperature. It is therefore concluded that for Helgoland waters temperature controlled egg production by its effect on prosome length, and that food conditions were not limiting.
منابع مشابه
Temperature cycles affect colonization potential of calanoid copepods.
Marine calanoid copepods colonize new habitats, and some become invasive. Their fitness, measured by intrinsic growth rate and net reproductive rate, is partially driven by biochemical processes. Thus, it is a function of ambient temperature. Biochemical processes may not be approximated well by yearly mean temperature alone when temperature cycles yearly, largely. Higher order moments may also...
متن کاملLatest Diversity Trend and Seasonal Abundance of Population of Zooplankton (Holoplankton) Communities in the South Caspian Sea, Iran
Seasonal variations of zooplankton communities were studied in the southern Caspian Sea for 4 successive seasons and 8 transects with 5 stations from 5 to 100 m depths which sampled during 2009. The zooplankton population constituted of 73.33% copepods, 24.21% rotifers, 2.23% cladocerans and 0.23% protozoans. Copepods were dominant at all stations with a density between 1456±531 ind. m-3 (Trans...
متن کاملComparison of molecular species identification for North Sea calanoid copepods (Crustacea) using proteome fingerprints and DNA sequences.
Calanoid copepods play an important role in the pelagic ecosystem making them subject to various taxonomic and ecological studies, as well as indicators for detecting changes in the marine habitat. For all these investigations, valid identification, mainly of sibling and cryptic species as well as early life history stages, represents a central issue. In this study, we compare species identific...
متن کاملShort communication:First report of cyclopoid copepods (oithonidae) from north-eastern Arabian Sea, Karachi, Pakistan
متن کامل
Intraspecific Differences in Lipid Content of Calanoid Copepods across Fine-Scale Depth Ranges within the Photic Layer
Copepods are among the most abundant and diverse groups of mesozooplankton in the world's oceans. Each species has a certain depth range within which different individuals (of the same life stage and sex) are found. Lipids are accumulated in many calanoid copepods for energy storage and reproduction. Lipid content in some species increases with depth, however studies so far focused mostly on te...
متن کامل