Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 437769
Title Effects of resources and mortality on the growth and reproduction of Nile perch in Lake Victoria
Author(s) Downing, A.S.; Nes, E.H. van; Wolfshaar, K.E. van de; Scheffer, M.; Mooij, W.M.
Source Freshwater Biology 58 (2013)4. - ISSN 0046-5070 - p. 828 - 840.
DOI https://doi.org/10.1111/fwb.12089
Department(s) Aquatic Ecology and Water Quality Management
Vis
Wageningen Marine Research
WIMEK
Publication type Refereed Article in a scientific journal
Publication year 2013
Keyword(s) lates-niloticus l - size-structured populations - life-history traits - haplochromine cichlids - east-africa - mwanza gulf - nyanza-gulf - competition - predation - dynamics
Abstract 1. A collapse of Nile perch stocks of Lake Victoria could affect up to 30 million people. Furthermore, changes in Nile perch population size-structure and stocks make the threat of collapse imminent. However, whether eutrophication or fishing will be the bane of Nile perch is still debated. 2. Here, we attempt to unravel how changes in food resources, a side effect of eutrophication, and fishing mortality determine fish population growth and size structures. We parameterised a physiologically structured model to Nile perch, analysed the influence of ontogenetic diet shifts and relative resource abundances on existence boundaries of Nile perch and described the populations on either side of these boundaries. 3. Our results showed that ignoring ontogenetic diet shifts can lead to over-estimating the maximum sustainable mortality of a fish population. Size distributions can be indicators of processes driving population dynamics. However, the vulnerability of stocks to fishing mortality is dependent on its environment and is not always reflected in size distributions. 4. We suggest that the ecosystem, instead of populations, should be used to monitor long-term effects of human impact.
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