Diversity and composition of benthic marine communities under contrasting management and temperature regimes

The sustainable management of small-scale fisheries is key for the well-being of coastal communities. Environmental conditions are known to influence the ecology of the coastal zone, yet their interactions with fisheries management regimes remains poorly understood. We examined spatial changes in the structure of benthic communities under distinct management regimes (TURF or Territorial Use Rights for Fisheries, and OA or open access areas) located in areas with different temperature patterns (warm and cold). Using underwater visual censuses, we assessed benthic community patterns across four locations in northern-central Chile and examined how species diversity and composition varied between management and environmental regimes. Our results showed that communities differed significantly between management and temperature regimes. In general, sessile community richness was 65% higher under cold regimes compared to warm regimes. For mobile invertebrates, richness and diversity were 42% and 41% greater in TURF areas than in OA areas, while both attributes were 4% and 5% higher under cold than warm temperature regimes. In the case of fish communities, species composition varied as a function of the interaction between management and temperature regimes. In cold sites, benthic communities within TURF areas were characterized by the kelp Lessonia trabeculata , the whelk Concholepas concholepas , and keyhole limpets ( Fissurella spp.), whereas OA areas were dominated by kelp, the sea urchin Arbacia nigra , and the starfish Meyenaster gelatinosus . Benthic communities of TURF areas in warm sites were associated with anemones, sea urchins and kelps, whereas OA areas were dominated mainly by anemones and sea urchins. Overall, our results support the notion that the structure of benthic communities can be influenced by an interaction between management regime and environmental conditions. The two temperature regimes stem from the differential exposure to coastal upwelling between sites, which suggests that other environmental processes, such as productivity or wave exposure, are implicated. Overall, the marked ecological differences between TURF and OA areas under contrasting temperature patterns suggest that environmental conditions should be incorporated into the design of novel fishery policies to promote the sustainable management of small-scale coastal fisheries.