Marine reserves are an effective tool for conservation and fisheries management in tropical marine ecosystems. They provide benefits to surrounding areas through the export of eggs, larvae, juveniles and adults to other reserves and fished areas. To increase conservation and fisheries benefits, connectivity (i.e. demographic linking of local populations through the dispersal of individuals as larvae, juveniles or adults) is a key ecological factor to consider when designing marine reserves. Consideration of the spatial scale of movement of coral reef fish species at each stage in their life cycle is also critically important in designing the size, spacing and location of networks of marine reserves.
This study evaluates movement patterns of 34 families (210 species) of coral reef fishes. Results showed that movement patterns (home ranges, ontogenetic shifts and spawning migrations) vary among and within species, and are influenced by a variety of factors such as size, sex, behavior, density, habitat characteristics, season, tide and time of day. The following recommendations on the size, spacing and location of marine reserves are made:
- Marine reserves should be more than twice the size of the home range of focal species (in all directions). Marine reserves of various sizes will be required depending on which species need protection, how far they move, and if other effective protection is in place outside reserves.
- Reserve spacing should be <15 km, with smaller reserves spaced more closely.
- Marine reserves should include habitats that are critical to the life history of focal species (e.g. home ranges, nursery grounds, migration corridors and spawning aggregations), and be located to accommodate movement patterns among these.
In addition to connectivity, other ecological considerations are required to ensure that the design of marine reserves maximize their benefits for conservation and fisheries management: (a) representing 20–40% of each habitat in marine reserves to ensure that a large proportion of the meta-population is protected overall; (b) protecting at least three widely separated examples of each habitat in marine reserves to minimize the risk that they might all be adversely impacted by a single disturbance; (c) ensuring marine reserves are in place for the long term; (d) protecting special and unique areas in marine reserves (e.g. resilient sites, turtle nesting areas, FSAs); (e) minimizing and avoiding threats in marine reserves; and (f) creating large multiple-use MPAs that include, but are not limited to, marine reserves.
Recommendations in this paper can be used by practitioners to design marine reserve networks to maximize benefits for focal species. In addition, recommendations for marine reserve network design regarding connectivity of reef fish populations must be considered alongside other ecological design criteria, and applied within different, context-dependent, socioeconomic and governance constraints.
Author: Green, A. L., A.P. Maypa, G.R. Almany, K.L. Rhodes, R. Weeks, R.A. Abesamis, M.G. Gleason, P.J. Mumby, and A.T. White
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Biological Reviews 90: 1215–1247. doi: 10.1111/brv.12155