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Management of summer-spawning herring off Iceland 总被引:1,自引:0,他引:1
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Coral mortality may result in macroalgal proliferation or a phase shift into an alga-dominated state. Subtidal, high-latitude western Indian Ocean coral communities at Sodwana Bay on the KwaZulu-Natal coast, South Africa, have experienced some mortality because of warm-water anomalies, storms and other causes, but the response of the macroalgae is unknown. We investigated the abundance and diversity of benthic algae on different hard natural substrata (dead digitate, brain and plate corals and beach rock) on Two-Mile Reef, Sodwana Bay. We also compared algal communities colonising ceramic, marble and pretreated ceramic tiles placed on the reef for six months. We identified 95 algae (14 Chlorophyta, 11 Phaeophyceae, 69 Rhodophyta and one cyanobacterium). Assemblages on natural and artificial substrata were dominated by the brown alga Lobophora variegata (Lamouroux) Womersley ex Oliveira and non-geniculate corallines (Rhodophyta, Corallinaceae). Cluster and ordination analyses revealed that the algae showed no affinity for particular substrata, whether natural or artificial. Algal cover was occasionally higher on rougher tiles and crustose corallines were significantly more abundant on marble than ceramic tiles. Two-Mile Reef had 23.1% dead and 48.4% live scleractinian coral cover, where dead corals were colonised indiscriminately by many small algal species, but there was no evidence of algal proliferation. The results provide a baseline for monitoring this high-latitude reef system. 相似文献
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Throughout Southeast Asia, blast fishing creates persistent rubble fields with low coral cover and depauperate fish communities. We stabilized a 20-year-old rubble field in a Marine Protected Area in the Philippines, using plastic mesh and rock piles in replicated 17.5m(2) plots, thereby increasing topographic complexity, fish habitat, and recruitment substrate surface area. Multivariate analysis revealed fish community shifts within the rehabilitated area from that characteristic of rubble fields to one similar to the adjacent healthy reef within three years, as measured by changes in fish abundance and body size. Coral recruitment and percent cover increased over time, with 63.5% recruit survivorship within plots, compared with 6% on rubble. Our low-cost approach created a stable substrate favoring natural recovery processes. Both rehabilitation and the elimination of poaching were integral to success, emphasizing the synergism between the two and the need to incorporate both when considering mitigation. 相似文献