SOURCES, SINKS, AND THE DESIGN OF MARINE RESERVE NETWORKS

Recently, enthusiasm has been growing for ''source and sink'' theory i n understanding how dispersal influences replenishment of marine popul ations. Sources are areas that contribute disproportionately large qua ntities of recruits to future generations; sinks receive recruits but contribute little. This simple idea has been taken up by those seeking to optimize the location of no-take marine reserves. Reserves in sour ce areas are argued to be better than those in sinks in terms of value for fisheries enhancement and conservation. However, attempting to id entify sources and sinks is extremely difficult and may run contrary t o management objectives by delaying reserve establishment. In any case , it is highly likely that different species have different source and sink areas and that the locations of such areas will change through t ime. The surest way to achieve fishery and conservation goals will be to establish dense networks of reserves that incorporate a wide variet y of habitats and locations. We create source areas when we create no- take reserves.