Development time and growth rate of the marine calanoid copepod Temora longicornis as related to food conditions in the Oosterschelde estuary (southern North Sea)
Bakker, C.; Van Rijswijk, P. (1987). Development time and growth rate of the marine calanoid copepod Temora longicornis as related to food conditions in the Oosterschelde estuary (southern North Sea). Neth. J. Sea Res. 21(2): 125-141. http://dx.doi.org/10.1016/0077-7579(87)90028-7
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
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| Auteurs | | Top |
- Bakker, C.
- Van Rijswijk, P., meer
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| Abstract |
The development time of the larval stages of the marine calanoid copepod Temora longicornis was estimated by applying the multi-cohort model of BOSSICART (1980) on observed densities of 3 successive cohorts in the open Oosterschelde estuary (SW Netherlands) during 1983 and 1984. The shortest development time of nauplii + copepodids of 16 to 25 days occurred in spring; the maximum development time of both series of stages was 27 to 43 days and was found in summer. This longer time of development could be ascribed to a smaller food supply during this period. The development time of the larval stages was significantly correlated with smaller phytoplankton cells (spherical equivalent diameter <=50 µm). Lowest daily exponential k-values (0.04) were calculated for summer periods (17 to 20°C) and highest values (k=0.23) were found during spring (~10°C). From 1986 onwards, the tidal regime in the estuary has been modified by an artificial storm-surge barrier, implying a decrease in current velocity and leading to shifts in phytoplankton composition and densities in the eastern part. It is hypothesized that normal conditions for growth of nauplii and smaller copepodids of Temora in this section will continue in the future, but that those for growth and development of adults may become less favourable. |
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