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Population structure and reproduction ofCalanus helgolandicus (Copepoda, Calanoida) along the iberian and Moroccan slope
Helgoländer Meeresuntersuchungen volume 50, pages 457–475 (1996)
Abstract
During three cruises, carried out in March 1991, October 1991, and January 1992 off the Iberian Peninsula and Morocco, the abundant calanoid copepodCalanus helgolandicus (Claus) was collected from a depth of 1000 m to the surface. Differences in depth preference were correlated with the life stage and geographically differing vertical salinity structures. In autumn and winter, only stage V copepodids (CV) and adults were found, in spring also younger copepodid stages. Within the range of the Mediterranean outflow water (MOW), a sharp decline of abundances of all stages was evident during all cruises. In autumn 1991, the bulk of the population was recorded south of the MOW, in winter 1992 north of it. During winter, numbers had declined by 70%, supporting the idea that winter individuals represent the same generation as was encountered in autumn, and that they had been transported northwards. CV stages preferred the depth layer 400–800 m, in autumn and winter. Adults were found in autumn at the same depth south of the MOW, while they preferred the 0–400 m layers north of it. In winter, the abundance of adults increased, males preferred the 400–600 m depth layer, while females stayed at 200–400 m. In spring 1991, stages younger than CV were found in high densities, all stages concentrating in the upper 200 m. During the crosslope survey in spring off Portugal, an absolute abundance maximum of females was found. In contrast, offshore densities were very low. On the basis of these findings, the hypothesis of a Mediterranean centre of distribution and dispersal into the Atlantic is questioned. It is suggested that a separate, reproductively active population ofC. helgolandicus exists off NW. Africa.
Literature Cited
Brenning, U., 1981. Beiträge zur Calanoidenfauna (Crustacea, Copepoda) vor Nordwest- und Südwestafrika. I. Die Vertreter der Familie Calanidae. — Wiss. Z. Wilhelm-Pieck-Univ. Rostock30 (4–5), 1–12.
Conover, R. J., 1988. Comparative life histories in the generaCalanus andNeocalanus in high latitudes of the northern hemisphere. — Hydrobiologia167–168, 127–142.
Deevey, G. B. & Brooks, A. L., 1977. Copepods of the Sargasso Sea off Bermuda: Species composition, and vertical and seasonal distribution between the surface and 2000 m. — Bull. mar. Sci.27, 256–291.
Fleminger, A. & Hülsemann, K., 1977. Geographical range and taxonomic divergence in North AtlanticCalanus (C. helgolandicus, C. finmarchicus andC. glacialis). — Mar. Biol.40, 233–248.
Green, E. P., Harris, R. P. & Duncan, A., 1993. The seasonal abundance of the copepodite stages ofCalanus helgolandicus andPseudocalanus elongatus off Plymouth. — J. mar. biol. Ass. U. K.73, 109–122.
Greze, V. N., Kovalev, A. V., Baldina, E. P., Bileva, O. K. & Shmeleva, A. A., 1985. Zooplankton transfer through the Gibraltar Strait and peculiarities of its taxonomic composition and distribution in adjacent areas. — Investigación pesq.49, 3–13.
Hempel, G. & Weikert, H., 1972. The neuston of the subtropical and boreal north-eastern Atlantic Ocean. A review. — Mar. Biol.13, 70–88.
Kouwenberg, J., 1993. Sex ratio of calanoid copepods in relation to population composition in the northwestern Mediterranean. — Crustaceana64, 281–299.
Peterson, W. T., Miller, C. B. & Hutchinson, A., 1979. Zonation and maintenance of copepod populations in the Oregon upwelling zone. — Deep-Sea Res. (A)26, 467–494.
Roe, H. S. J., 1972. The vertical distributions and diurnal migrations of calanoid copepods collected on the Sond cruise, 1965. II. Systematic account: Families Calanidae up to and including the Aetideidae. — J. mar. biol. Ass. U. K.52, 315–343.
Verheye, H. M., Hutching, L., Huggett, J. A. & Painting, S. J., 1992. Mesozooplankton dynamics in the Benguela ecosystem, with emphasis on the herbivorous copepods. — S. Afr. J. mar. Sci.12, 561–584.
Weikert, H. & John, H.-Ch., 1981. Experiences with a multiple opening-closing plankton net. —J. Plankt. Res.3, 167–176.
Williams, R., 1985. Vertical distribution ofCalanus finmarchicus andC. helgolandicus in relation to the development of the seasonal thermocline in the Celtic Sea. — Mar. Biol.86, 145–149.
Williams, R. & Conway, D. V. P., 1988. Vertical distribution and seasonal numerical abundance of the Calanidae in oceanic waters to the south-west of the British Isles. — Hydrobiologia167–168, 259–266.
Wroblewski, J. S., 1982. Interaction of currents and vertical migration in maintainingCalanus marshallae in the Oregon upwelling zone — a simulation. — Deep-Sea Res. (A)29, 665–686.
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Stöhr, S., Schulz, K. & John, H.C. Population structure and reproduction ofCalanus helgolandicus (Copepoda, Calanoida) along the iberian and Moroccan slope. Helgolander Meeresunters 50, 457–475 (1996). https://doi.org/10.1007/BF02367161
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DOI: https://doi.org/10.1007/BF02367161