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Simulated carrying capacities of fish in Norwegian fjords
Author(s) -
VANES ANNE GRO VEA SAL,
AKSNES DAG,
FOSSÅ JAN HELGE,
GISKE JARL
Publication year - 1995
Publication title -
fisheries oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 80
eISSN - 1365-2419
pISSN - 1054-6006
DOI - 10.1111/j.1365-2419.1995.tb00058.x
Subject(s) - zooplankton , oceanography , trophic level , pelagic zone , fjord , environmental science , fishery , habitat , biomass (ecology) , calanus finmarchicus , geography , ecology , geology , biology , copepod , crustacean
The influence of oceanographic and meteorological conditions and topography on the carrying capacity of organisms in coastal areas of western Norway is investigated by field studies and dynamic modelling. Published data on Calanus finmarchicus , the dominant species in the zooplankton biomass of west Norwegian coastal waters, demonstrate a strong gradient, with high densities at the outer coastal areas and lower densities at the innermost localities. This gradient spans several orders of magnitude. A similar tendency is found in the data from pelagic trawling and from beach seine catches, and simulation modelling indicates that fish production depends on zooplankton availability. According to the model, the carrying capacity level of fish production is high in the outer areas and decreases with distance from the outer coast according to the decrease in advected biomass of zooplankton. The simulations indicate that while growth prospects for individuals at lower trophic levels vary with the distance from the coast, potential for growth seems largely unaffected by the distance from the coast for the sublittoral piscivores (e.g. cod). This indicates that, for immigration of a new sublittoral piscivore to a habitat, it does not matter whether the habitat is situated close to the outer coast or far from it. A consequence for stock enhancement may be that a small‐scale release of sublittoral piscivores will be equally productive in most coastal areas, while the outcome of a large‐scale release will be strongly dependent on distances from the coast. The outcome may be high, but variable, in the outer areas and low, but probably more constant in the innermost areas, provided that releases of juvenile, sublittoral, piscivorous fish do not result in a fish stock density in excess of the carrying capacity level.