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91.
The need for new instruments and systems for environment monitoring encouraged the development of a network of coastal platforms combining a high versatility with ease of use and affordability. Almost every instrument can be fitted on the platforms, thanks to the large amount of available power provided by both solar panels and wind generators. All the platforms host a pumping system that pumps water from five depths into a measurement chamber where a multiparametric probe is fitted and from where other devices (e.g. samplers or analysers) can draw samples. In situ temperature measurements are provided at the same pumping depths. A colorimetric nutrient analyser and a meteorological station complete the basic equipment. On one of the platforms, a remotely controlled water sampler and an ADCP are also fitted. The data-acquisition and transmission system enables the platform to be controlled remotely using a special macro-commands set. Several examples of use are presented. 相似文献
92.
We analysed fisheries trends in the northern region of the Gulf of California, within the Biosphere Reserve of the Upper Gulf of California and Colorado Delta River and the Vaquita Refuge Area, and suggest measures to protect the vaquita, Phocoena sinus. We compiled and analysed catch reports of artisanal fishermen in the three fishing communities of the Upper Gulf of California (San Felipe in the State of Baja California, and Golfo de Santa Clara and Puerto Peñasco in the State of Sonora) from 1995 to 2007. This information was categorised with respect to geographic information systems, and all fishing sites within two marine protected areas in the region were identified. In addition, from a survey based on direct interviews with artisanal fishermen in each of the three ports, we identified that 23% of fishermen will continue fishing despite on-going fishing buy-out programmes in the region. We suggest several specific courses of action to decrease the fishing impact on this critically endangered cetacean. However, given the critical situation of this critically endangered species, it is very uncertain whether enforcing a no-take zone within the biosphere reserve and the Vaquita Refuge Area, or even a wider fishing moratorium, will be enough to save this endangered species from extinction. 相似文献
93.
Although it is recognized that marine wild-capture fisheries are an important source of food for much of the world, the cost of sustainable capture fisheries to species diversity is uncertain, and it is often questioned whether industrial fisheries can be managed sustainably. We evaluated the trade-off among sustainable food production, profitability, and conservation objectives in the groundfish bottom-trawl fishery off the U.S. West Coast, where depletion (i.e., reduction in abundance) of six rockfish species (Sebastes) is of particular concern. Trade-offs are inherent in this multispecies fishery because there is limited capacity to target species individually. From population models and catch of 34 stocks of bottom fish, we calculated the relation between harvest rate, long-term yield (i.e., total weight of fish caught), profit, and depletion of each species. In our models, annual ecosystem-wide yield from all 34 stocks was maximized with an overall 5.4% harvest rate, but profit was maximized at a 2.8% harvest rate. When we reduced harvest rates to the level (2.2% harvest rate) at which no stocks collapsed (<10% of unfished levels), biomass harvested was 76% of the maximum sustainable yield and profit 89% of maximum. A harvest rate under which no stocks fell below the biomass that produced maximum sustainable yield (1% harvest rate), resulted in 45% of potential yield and 67% of potential profit. Major reductions in catch in the late 1990s led to increase in the biomass of the most depleted stocks, but this rebuilding resulted in the loss of >30% of total sustainable yield, whereas yield lost from stock depletion was 3% of total sustainable yield. There are clear conservation benefits to lower harvest rates, but avoiding overfishing of all stocks in a multispecies fishery carries a substantial cost in terms of lost yield and profit. 相似文献
94.
Sensitivity analysis of the two dimensional application of the Generic Ecological Model (GEM) to algal bloom prediction in the North Sea 总被引:2,自引:0,他引:2
Harmful algae can cause damage to co-existing organisms, tourism and farmers. Accurate predictions of algal future composition and abundance as well as when and where algal blooms may occur could help early warning and mitigating. The Generic Ecological Model is an instrument that can be applied to any water system (fresh, transitional or coastal) to calculate the primary production, chlorophyll-a concentration and phytoplankton species composition. It consists of physical, chemical and ecological model components which are coupled together to build one generic and flexible modelling tool. In this paper the model has been analyzed to assess sensitivity of the simulated chlorophyll-a concentration to a subset of ecologically significant input factors. Only a small number of approaches could be considered as suitable for several reasons including the model complexity, engagement of numerous interacting parameters and relatively long time of a single simulation. Thus, sensitivity analysis has been carried out with the use of the Morris method and later enriched by the computation of the correlation ratios of the selected parameters on the model response at more than a few locations in the modelled area. The obtained results are in agreement with expert knowledge of the ecological processes in the North Sea and correspond well with local characteristics. 相似文献
95.
Modeling estuarine-shelf exchanges in a deltaic estuary: Implications for coastal carbon budgets and hypoxia 总被引:1,自引:0,他引:1
The export of wetland-derived materials to the coastal ocean (i.e., the “Outwelling” hypothesis) has received considerable attention over the past several decades. While a number of studies have shown that estuaries export appreciable amounts of nutrients and carbon, few studies have attempted to estimate the importance of estuarine sources for the coastal carbon budgets in river-dominated coastal ecosystems. A novel tidal prism model was developed to examine estuarine-shelf exchanges in the Barataria estuary, a deltaic estuary located in the north-central Gulf of Mexico. This estuary has been the site of a massive wetland loss, and it has been hypothesized that carbon export from the eroding coastal wetlands supports the development of a large hypoxic zone in the coastal Gulf of Mexico. The model results show that the Barataria estuary receives nitrogen through the tidal passes and releases carbon to the coastal ocean. The mean calculated tidal water discharge of 6930 m3 s−1 is equivalent to about 43% of the lower Mississippi River discharge. The annual total organic carbon (TOC) export is 109 million kg, or 57 gC m2 yr−1 when prorated to the total water area of the estuary. This carbon export is equivalent to a loss of 0.5 m of wetland soil horizon over an area of 8.4 km2, and accounts for about 34% of the observed annual wetland loss in the estuary between 1978 and 2000. Compared to the lower Mississippi River, the Barataria estuary appears to be a very small source of TOC for the northern Gulf of Mexico (2.7% of riverine TOC), and is unlikely to have a significant influence on the development of the Gulf's hypoxia. 相似文献
96.
97.
Accounting for the mismanagement of tropical nearshore fisheries 总被引:2,自引:0,他引:2
The underlying reason for the mismanagement of tropical nearshore fisheries is the implementation of policies and programs
based on Western models and approaches, coupled with an inability and/or unwillingness to consider non-Western alternatives
of empirically proven value. Such attitudes are embedded in donor and development agency behavior, and are demonstrated by
the temperate bias in conventional approaches to fisheries education and management, with a corresponding lack of understanding
of tropical milieux, and in the persistence of various prejudices. Adaptive Management, The Ecosystem Approach, Local Knowledge,
and Protected Areas are discussed from the perspectives of Western models and pre-existing Pacific Island systems as alternative
models. Given the parlous condition of the global environment and resources, the best non-Western pre-existing models and
Western approaches must be blended to provide sustainable solutions.
相似文献
Francis R. HickeyEmail: |
98.
Assessing the impact of fisheries co-management interventions in developing countries: a meta-analysis 总被引:2,自引:0,他引:2
Co-management is now established as a mainstream approach to small-scale fisheries management across the developing world. A comprehensive review of 204 potential cases reveals a lack of impact assessments of fisheries co-management. This study reports on a meta-analysis of the impact of fisheries co-management in developing countries in 90 sites across 29 case-studies. The top five most frequently measured process indicators are participation, influence, rule compliance, control over resources, and conflict. The top five most frequently measured outcome indicators are access to resources, resource well-being, fishery yield, household well-being, and household income. To deal with the diversity of the 52 indicators measured and the different ways these data are collected and analysed, we apply a coding system to capture change over time. The results of the meta-analysis suggest that, overall fisheries co-management delivers benefits to end-users through improvements in key process and outcome indicators. However, the dataset as a whole is constituted primarily of data from the Philippines. When we exclude this body of work, few generalisations can be made about the impact of fisheries co-management. The lack of comparative data suitable for impact assessment and the difficulties in comparing data and generalising across countries and regions reiterates calls in other fields for more systematic approaches to understanding and evaluating governance frameworks. 相似文献
99.
Jongseong Ryu Thomas M. Leschine Jungho Nam Won Keun Chang Karen Dyson 《Journal of environmental management》2011
This report proposes a method for assessing resilience-building components in coastal social–ecological systems. Using the proposed model, the preferences of experts in Masan Bay (South Korea) and Puget Sound (USA) are compared. A total of 30 management objectives were determined and used to build a hierarchic tree designed using the principles of the Analytic Hierarchy Process (AHP). Surveys were performed with 35 Puget Sound experts using face-to-face interviews and with 28 Masan Bay experts by mail. The results demonstrate that the legal objective, which enables legislation, was the highest preferred component in both regions. The knowledge translation variable was also given a high preference score in both regions. An analysis of variance (ANOVA) showed that the Puget Sound experts significantly favored attention to education, habitat restoration and species protection objectives in comparison to the Masan Bay experts. The Masan Bay experts placed greater emphasis on legislation and the type of institutional design than did the Puget Sound experts. Using cluster analysis, four distinct groups of respondents were independently identified in Puget Sound and three groups were identified in Masan Bay. One unique subgroup in the Puget Sound experts group, which was characterized by its high preferences for habitat restoration and species protection, was not observed in Masan Bay. Demographic variables (length of career and role in coastal issue) failed to account for the differences in groupings and preferences in either region, except for the variable ‘favoring information source’ in the Puget Sound group. This finding implies that the demographic information was not related to differences in group opinions in both regions. The analysis framework presented here was effective in identifying expert preferences regarding the overall structure and emphasis in coastal management programs. Thus, this framework can be applied towards coastal policy development. 相似文献
100.
Community-level resource management efforts are cornerstones in ensuring sustainable use of natural resources. Yet, understanding how community characteristics influence management practices remains contested. With a sample size of ≥725 communities, we assessed the effects of key community (i.e., socioeconomic) characteristics (human population size and density, market integration, and modernization) on the probability of occurrence of fisheries management practices, including gear, species, and spatial restrictions. The study was based in Solomon Islands, a Pacific Island country with a population that is highly dependent on coastal fisheries. People primarily dwell in small communities adjacent to the coastline dispersed across 6 island provinces and numerous smaller islands. We used nationally collected data in binomial logistic regression models to examine the likelihood of management occurrence, given socioeconomic context of communities. In contrast to prevailing views, we identified a positive and statistically significant association between both human population size and market integration and all 3 management practices. Human population density, however, had a statistically significant negative association and modernization a varied and limited association with occurrence of all management practices. Our method offers a way to remotely predict the occurrence of resource management practices based on key socioeconomic characteristics. It could be used to improve understanding of why some communities conduct natural resource management activities when statistical patterns suggest they are not likely to and thus improve understanding of how some communities of people beat the odds despite limited market access and high population density. 相似文献