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TEMPORAL DENSITY DEPENDENCE AND POPULATION REGULATION IN A MARINE FISH
Author(s) -
Webster Michael S.
Publication year - 2003
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2003)084[0623:tddapr]2.0.co;2
Subject(s) - density dependence , predation , population density , ecology , population , biology , coral reef fish , coral reef , marine ecosystem , abundance (ecology) , ecosystem , reef , population dynamics of fisheries , fish <actinopterygii> , fishery , demography , sociology
Population regulation requires between‐generation temporal density dependence, which has proved difficult to document unequivocally in nature, especially in marine fishes. Field experiments and observations in the Bahamas demonstrated that such population regulation occurs in the coral‐reef fish Gramma loreto . I performed manipulative field experiments that identified mortality as the primary source of demographic density dependence among local populations. The causative mechanism involved a response in the behavior of predators, which both aggregated and spent more time hunting where prey fish densities were high. Spatially density‐dependent mortality (i.e., density dependence among populations) led to between‐generation temporal density dependence (i.e., density dependence within populations over time) indicative of population regulation. Over three years—roughly two generations—local populations followed regular annual cycles of abundance that stemmed from seasonal patterns of recruitment. Despite considerable natural and experimentally induced variability in the recruitment of new individuals, adult density remained nearly constant. Because multispecies interactions such as predation can be necessary to regulate marine populations, effective management and conservation requires an ecosystem approach that preserves these interactions. Corresponding Editor: J. E. Havel