Short-term variability during an anchor station study in the southern Benguela upwelling system: fecundity estimates of the dominant copepod, Calanoides carinatus
Armstrong, D.A.; Verheye, H.M.; Kemp, A.D. (1991). Short-term variability during an anchor station study in the southern Benguela upwelling system: fecundity estimates of the dominant copepod, Calanoides carinatus. Prog. Oceanogr. 28(1-2): 167-188. http://dx.doi.org/10.1016/0079-6611(91)90025-H
In: Progress in Oceanography. Pergamon: Oxford,New York,. ISSN 0079-6611; e-ISSN 1873-4472, more
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| Authors | | Top |
- Armstrong, D.A.
- Verheye, H.M.
- Kemp, A.D.
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| Abstract |
Fecundity studies by indirect (Egg Ratio) and direct (bottle incubation) methods showed that egg production by Calanoides carinatus, downstream of a major upwelling centre, was closely coupled to hydrologically-mediated fluctuations in food availability. Fecundity estimates derived using the Egg Ratio method were lower than those from the incubation method, which we attribute to advection of egg-laden surface layers during upwelling. Improvements in understanding the fecundity-food relationship were achieved by considering phytoplankton size (cells >10µm), species composition and state of bloom development. Egg production was high (41.6 eggs female-1d-1) during a prolonged quiescent period while a monospecific bloom of Coscinodiscus gigas persisted, but it declined rapidly (5.4 eggs female-1d-1) on the bloom's senescence and its replacement by a surface microflagellate-dominated community. Resumption of egg production occurred with the advection of recently upwelled water supporting a healthy small diatom population. We suggest that the rapid response displayed by female C. carinatus to a pulsed and unpredictable food supply, combined with the capacity to store large lipid reserves, allows this species to successfully exploit upwelling regions. |
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