HARVEST REFUGIA IN MARINE INVERTEBRATE FISHERIES - MODELS AND APPLICATIONS TO THE RED-SEA URCHIN, STRONGYLOCENTROTUS-FRANCISCANUS

TitleHARVEST REFUGIA IN MARINE INVERTEBRATE FISHERIES - MODELS AND APPLICATIONS TO THE RED-SEA URCHIN, STRONGYLOCENTROTUS-FRANCISCANUS
Publication TypeJournal Article
Quinn JF, Wing SR, Botsford LW
Type of Articlearticle
Year of Publication1993
Volume33
Abstract

Benthic marine invertebrates with planktonic larvae may exhibit Allee effects in reproduction or recruitment. Hydrodynamic considerations and experimental evidence suggest that species broadcasting gametes suffer greatly reduced fertilization efficiencies as densities decline. There is also evidence for some species, including the red sea urchin, that post-dispersal recruitment success declines at low densities of adults, if adults provide shelter from predators or other sources of mortality. Species displaying strong Allee effects may be susceptible to catastrophic population collapses with slight increases in mortality due to harvesting or natural causes. A simple two patch logistic model suggests that the establishment of a harvest refuge is necessary to prevent collapses and maintain sustainable catches at high levels of harvesting effort. A more detailed, age structured model based on the biology of the red sea urchin, Strongylocentrotus franciscanus produces similar results. Effects of harvesting strategies are sensitive to Allee effects caused by both fertilization efficiency and the disruption of adult spine canopies. Theoretical requirements for the size and spacing of marine reserves depends upon the dispersal abilities of the target species. Multiple reserves, spaced more closely than the average larval dispersal distance, appear to be an effective and conservative strategy for maintaining healthy populations and sustainable levels of harvest.

JournalAMERICAN ZOOLOGIST
Pages537--550
KeywordsDEPENDENT SIZE REGULATION
Citation KeyQUINN1993