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121.
Southern California's marine areas are heavily contaminated with dichloro-diphenyl-trichloroethane (DDT) and polychlorinated-biphenyls (PCBs), and fish consumption advisories (FCAs) have been issued throughout the region. Between 2002 and 2003, the Montrose Angler Survey, a large-scale survey of subsistence anglers, was developed and implemented on site in Orange and Los Angeles counties. This survey was intended to assist natural resource trustees in the development of restoration programs that will address injuries to natural resources and restore lost economic services for anglers, but the data were never fully analyzed. The trustees have shown a clear preference for ecological restoration programs that may take years to improve fishing services. In contrast, this analysis, which includes a random-parameter fishing site choice model, demonstrates that simple, inexpensive programs such as better signage to warn of FCAs and transportation to clean sites have the potential to yield substantial benefits quickly. This paper also focuses on how different ethnic minority groups are affected by FCAs, and determines how best to communicate risk information and change fishing behavior through outreach programs. 相似文献
122.
Large intensity and diversity of human activities result in an increase in complexity in the utilization of space. This paper describes the fisheries and a method to map fishing efforts and catches of different fleets by combining vessel monitoring system (VMS) data and logbook data. The method makes it possible to explore the spatial and temporal variability of fishing and the potential impacts of proposed management measures on the fisheries. The method is proposed to be used in the development of management plans for marine protected areas such as Natura 2000 sites, designated to protect vulnerable habitats and species. 相似文献
123.
The sea cucumber Holothuria scabra is a widely distributed and economically important species that has been harvested in Kenya for decades. No previous studies have been carried out on the reproduction of this species in Kenya. Standard gonad index methods were used to analyze reproductive patterns of individuals collected monthly in 1998–1999, 2000–2001 and 2006–2007. Morphological characteristics, gonad tubule lengths and fecundity were also measured. Mean monthly gonad indices were significantly correlated between males and females indicating synchronous gonad development between the sexes. Gonad indices showed a biannual pattern that was consistent in all three years with a minor spawning event occurring between August and September and a major spawning event between November and December. The pattern of gonad growth showed significant variability between years and between months. Temporal changes in gonad growth correlated significantly with gonad tubule length and absolute fecundity. Monthly gonad indices also correlated significantly with monthly measurements of air temperature and light suggesting a possible role for both factors in timing gametogenesis and spawning. There was a shift in sex ratio from unity in the 1998–1999 and 2000–2001 samples to significantly more males in the 2006–2007 samples, as well as a significant reduction in mean sizes (body wall weight) and reproductive output (gonad index) which suggests that the reproductive success of this species is potentially negatively affected by fishing. 相似文献
124.
《Marine Policy》2016
The aim of this study was to empirically assess institutional aspects shaping fishers’ behavior leading to unsustainable resource use, by using the example of destructive drag-net fishing in Zanzibar, Tanzania. A broad institutional approach was used to specifically assess institutional factors influencing the fishers’ reasons for the current use of destructive drag-nets as well as their willingness- and economic capacity to change to less destructive gears. Different regulative, normative, cultural-cognitive and economic factors (tradition, group-belonging, social acceptance, common practice, identity of drag-net users and weak economic capacity) were identified as critical elements influencing the current use of destructive gears, as well as obstructing changes to other gears. Hence, the importance of addressing all of these factors, matching to the different contexts, rather than focusing on fast-moving regulative measures, is emphasized to increase chances of management success. More promising approaches would be resource allocations to more sustainable fishing gears, well-managed gear exchange programs, as well as alterations of slow-moving normative and cultural factors, e.g. awareness raising on the advantages of more sustainable fishing gears, their traditional and cultural values, information on the actual income they generate, as well as education and an exchange of traditional knowledge on how to use them. 相似文献
125.
Limiting accessibility to a fishing area can reduce fishing effort effectively and may therefore promote local recovery of depleted stocks. In January 2002, beach driving was banned in South Africa, thereby reducing angler access to large areas of the coastline, particularly in less-developed areas. In November 2001 a project had been established in the St Lucia Marine Reserve, on the east coast of South Africa, to compare surf-zone fish populations inside a no-take sanctuary zone with those in an adjacent exploited area. Subsequent to the ban, the aim of the project was adapted such that surf-zone fish populations were monitored for potential recovery in what had been the exploited area, located to the north of Cape Vidal, which anglers could no longer access easily, because of the prohibition on beach driving. Standardised research fishing was conducted at two sites in the previously exploited area and two sites in the no-take sanctuary. Conventional stock-status indicators showed evidence of recovery in the four most common species caught in the previously exploited area, in terms of both abundance and biomass. Generalised additive mixed models were used to account for the influence of targeting specific species; however, subtle differences in habitat between the sampling sites, improved angling skill over time, variability in recruitment, and differential species-specific responses complicated interpretation of results. The implications of the findings are discussed in terms of the future monitoring and management of marine protected areas both within the St Lucia Marine Reserve and farther afield. 相似文献
126.
ML Camara B Mérigot F Leprieur JA Tomasini I Diallo M Diallo 《African Journal of Marine Science》2016,38(2):189-206
In a context of growing fishing pressures and recommendations for an ecosystem approach to fisheries, there is a need to monitor changes in fish communities over time. In this study, we analysed data from scientific trawl surveys carried out on the continental shelf off Guinea between 1985 and 2012. We performed factorial analyses and calculated biodiversity indices to characterise the changes in the structure and composition of fish communities that occurred over the 28-year period in this area, particularly given intensive fishing activities. We show that, over the study period, fish communities on the Guinean shelf were structured primarily according to spatial factors, with temporal changes being less pronounced than expected. However, a temporal analysis of biodiversity indices and species dominance showed that the intensification of fishing had significant effects on the general ecological features of the fish assemblages under study. There was a decrease in fish density and in mean trophic level. In addition, there were changes in species dominance, whereby large, slow-growing species with high commercial value were gradually replaced by smaller, fast-growing species of lesser commercial interest. These results from field observations are in line with some conclusions from previous modelling studies in the same geographical area, and provide further support for the hypothesis of a progressive ‘ecosystem effect of fishing’ occurring in Guinean waters. 相似文献
127.
North Sea cod recovery? 总被引:3,自引:3,他引:3
128.
Frid C. L. J; Harwood K. G.; Hall S. J.; Hall J. A. 《ICES Journal of Marine Science》2000,57(5):1303-1309
129.
130.