995 resultados para rocky reef


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Age-based analyses were used to demonstrate consistent differences in growth between populations of Acanthochromis polyacanthus (Pomacentridae) collected at three distance strata across the continental shelf (inner, mid-, and outer shelf) of the central Great Barrier Reef (three reefs per distance stratum). Fish had significantly greater maximum lengths with increasing distance from shore, but fish from all distances reached approximately the same maximum age, indicating that growth is more rapid for fish found on outer-shelf reefs. Only one fish collected from inner-shelf reefs reached >100 mm SL, whereas 38−67% of fish collected from the outer shelf were >100 mm SL. The largest age class of adult-size fish collected from inner and mid-shelf locations comprised 3−4 year-olds, but shifted to 2-year-olds on outer-shelf reefs. Mortality schedules (Z and S) were similar irrespective of shelf position (inner shelf: 0.51 and 60.0%; mid-shelf: 0.48 and 61.8%; outer shelf: 0.43 and 65.1%, respectively). Age validation of captive fish indicated that growth increments are deposited annually, between the end of winter and early spring. The observed cross-shelf patterns in adult sizes and growth were unlikely to be a result of genetic differences between sample populations because all fish collected showed the same color pattern. It is likely that cross-shelf variation in quality and quantity of food, as well as in turbidity, are factors that contribute to the observed patterns of growth. Similar patterns of cross-shelf mortality indicate that predation rates varied little across the shelf. Our study cautions against pooling demographic parameters on broad spatial scales without consideration of the potential for cross-shelf variabil

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A compilation of 48 estimates of Caribbean and Pacific coral reef fish catches, ranging from 0.1 to 23.7 t km super(-2) year super(-1), obtained from coral reef areas ranging from 0.1 to nearly 4-10 super(5) km super(2), are used to show that observed catches, and hence potential yield estimates, depend strongly on the reference area. The implications for coral reef fisheries assessments are discussed.

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Growth parameters and mortality rates were estimated from length-frequency data sampled in 1982, using the FiSAT software, for three coral reef fish species, the surgeon fish (Ctenochaetus striatus), the damselfish (Stegastes nigricans) and the squirrel fish (Sargocentron microstoma) in Tiahura Reef, Moorea Island, French Polynesia.

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Although the live reef food fish trade has become an increasingly "hot" topic in the environmental press in recent months, many of the sources reporting on this practice have tended to focus on issues related to the rampant use of sodium cyanide in the trade, rather than the more pressing matter of the looming potential for overexploitation engendered by this practice. Presented in this article is a brief overview of the live reef food fish trade as it is practiced in eastern Indonesia covering the methods used and economics, geographic extent and numerous deleterious effects of the fishery.

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The article serves as anecdotal directory to the major fisheries, techniques and problems faced by the fishers in the coral reef area of Spermonde Archipelago, Southwest Sulawesi, Indonesia.

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Length-weight relationships were computed for 42 species of coral reef fishes from 14 families from the Alacran Reef (Yucatan, Mexico). A total of 1 892 individuals was used for this purpose. The fish species were caught by different fishing techniques such as fishhooks, harpoons, gill and trawl nets. The sampling period was from March 1998 to January 2000.

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Coral reefs are widespread along the east African coast and Seychelle islands. Their roles in island building and coastal protection are often underestimated, they are also important fishery habitats and major tourist attractions. The east African marine fishery production, estimated at 1.4-4.9 tonnes per km super(2), is principally a result of artisanal fishing. Siltation, trampling, and destructive fishing methods are the main cause of coral reef degradation along the east African coast and associated islands. Legislation has been implemented to protect coral reefs by establishing marine parks and reserves. However, poaching and anchor damage are widespread on these protected reefs. Legislative provision to increase the benefit to fishing communities may reduce poaching. The establishment of exclusive nature reserves may be one way to ensure preservation of some coral reefs in the region.

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This paper provides an overview of the live reef fish market in Hong Kong, which accounted for about 15,000 t/yr (US$345 million) of live fish imports in the mid-1990s. The live fish trade has spawned a number of management concerns, including overfishing of highly-valued species, use of destructive fishing techniques and human health risks. Recent actions by the Hong Kong government in response to these concerns are reported and possible region-wide initiatives are briefly discussed in this paper.

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ReefBase a global database of coral reefs systems and their resources was initiated at International Center for Living Aquatic Resources Management (ICLARM), Philippines in November 1993. The CEC has provided funding for the first two years and the database was developed in collaboration with the World Conservation Monitoring Centre in Cambridge, UK, as well as other national, regional, and international institutions. The ReefBase project activities and what ICLARM will do to accomplish the project objectives are briefly discussed.

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The region's scientists work together to formed the SEACORM Net (Southeast Asia Coral Reef Monitoring Network) for better integration of information and resources. The group intends to establish a strong working relationship between member countries, share information and lessons learnt, inform and update each other on research and monitoring activities in each country, and provide a mechanism for cross-country assistance and collaboration.

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The Global Coral Reef Monitoring Network (GCRMN) is an operational unit of the International Coral Reef Initiative (ICRI), established in 1995 and maintained by the Australian Institute of Marine Science (AIMS). The main responsibilities are to provide data and information on the global status of coral reefs, assess how people use and interact with reefs, assist coral reef management, and raise awareness among all stakeholders of the status of reefs and the need for urgent action. It is represented by 17 regional nodes, with overall coordination by a global coordinator based at AIMS.

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Two relatively inexpensive light traps to capture pre-settling reef fish and invertebrates are described. A trap made from a plastic bucket (with plastic bottles, a small plastic waste bin and two sheets of plywood) that costs US$15 appears to be just as effective as a large aluminium and plexiglass trap that costs US$275.