Habitat use and movement patterns of three sympatric fishes with different life history strategies: Implications for design of marine reserves.

摘要

Few coastal fisheries harvest only a single species. However, relatively little work has been focused on analyzing the design or utility of no-take marine reserves from a multi-species perspective. Sparisoma cretense, Pagrus pagrus and Pseudocaranx dentex are currently important target species for fisheries that co-occur in coastal areas of the Azores, mid-north Atlantic. I set out to document the biology and habitat usage of these three sympatric fish with different life histories, and combine it with habitat characteristics to evaluate the implications for an optimal design of marine reserves for managing these species individually and combined. I used three types of study: (1) reproductive biology, (2) underwater visual census or experimental fishing; (3) active tracking, passive acoustic monitoring and standard tag-recapture. The studies concentrated in the Faial Channel, which has been designated to become protected. Results showed large variability among and within these species in spatial behavior. Parrotfish have two distinct types of social organization, but both types are highly resident, use small home ranges on inshore reefs, and show reduced dispersal. A network of marine reserves of small size but including prime spawning areas could be effective in protecting its populations, although benefits to adjacent fisheries through spillover of adult fish would probably be limited to areas near reserve boundaries. Red porgy use home ranges which are one order of magnitude larger, and variable residency. It will require larger areas for permanent protection of red porgy, but ontogenic and density-dependent dispersal could promote considerable spillover of adults to benefit local fisheries. In contrast, trevally are highly vagile and can use large home ranges, especially in the summer spawning season, when individuals frequently visit multiple sites. Protecting such sites might help ensure successful sustained reproduction by the population and be the only feasible option. A network of several permanent medium-size reserve units plus seasonal protection of trevally habitat would result in a sub-optimal solution for any one species, but could achieve the goal of sustainable fisheries for all three species combined, have a good chance of acceptance by stakeholders, and make enforcement feasible.