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JOACHIM MAES KARIN E. LIMBURG ANTON VAN DE PUTTE FRANS OLLEVIER 《Fisheries Oceanography》2005,14(1):17-31
Herring (Clupea harengus) enter and remain within North Sea estuaries during well‐defined periods of their early life history. The costs and benefits of the migrations between offshore spawning grounds and upper, low‐salinity zones of estuarine nurseries are identified using a dynamic state‐variable model, in which the fitness of an individual is maximized by selecting the most profitable habitat. Spatio‐temporal gradients in temperature, turbidity, food availability and predation risk simulate the environment. We modeled predation as a function of temperature, the optical properties of the ambient water, the time allocation of feeding and the abundance of whiting (Merlangius merlangus). Growth and metabolic costs were assessed using a bioenergetic model. Model runs using real input data for the Scheldt estuary (Belgium, The Netherlands) and the southern North Sea show that estuarine residence results in fitter individuals through a considerable increase in survival probability of age‐0 fish. Young herring pay for their migration into safer estuarine water by foregoing growth opportunities at sea. We suggest that temperature and, in particular, the time lag between estuarine and seawater temperatures, acts as a basic cue for herring to navigate in the heterogeneous space between the offshore spawning grounds at sea and the oligohaline nursery zone in estuaries. 相似文献
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Abstract. Sixty-eight strains of Vibrio anguillarum , five of V. ordalii and the type strains of V. alginolyticus, V. carchariae, V. damsela and V. parahaemolyticus were compared using the API 20E gallery. Within the V. anguillarum strains, distinct groups could be separated mainly on the basis of their reaction on indole production and the fermentation of amygdalin and arabinose. Vibrio ordalii , the former V. anguillarum biotype 2, could easily be separated from V. anguillarum and from the other fish pathogenic Vibrio spp. 相似文献
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Abstract. Twenty-five Aeromonas hydrophila strains, isolated from freshwater fish and from freshwater samples were identified, using API 20NE and CH50. They were screened for the one plasmid (20 kb), and a third group (four strains) contained two or three plasmids. A 20 kb plasmid was common to all plasmid-positive strains. Although their plasmid profile differs, all groups are very similar with regard to their biochemical and physiological characterization. However, the differences observed using clustering can be explained by characteristics, some of which have been reported as virulence associated. No relationship between these factors and the presence of plasmids is found. The possibility of differentiating A. hydrophila strains on the basis of biochemical characteristics using a cluster analysis is considered. 相似文献
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