The Role of Ecolabeling in Fisheries Management and Conservation

Abstract:  The Marine Stewardship Council (MSC) regulates the ecolabeling of products from fisheries with the aim of promoting sustainable fishery practices. To date 11 fisheries have attained full certification and a further 7 are under review. Together these fisheries offer 220 ecolabeled marine products to consumers. Despite great potential to encourage sustainable fisheries, and thereby bring conservation benefits to marine systems, a range of issues may limit the wider uptake of MSC ecolabeled products. These include a general lack of consumer concern for marine fishes and sustainable fisheries, an absence of guaranteed continued financial benefits to participating fishers, and difficulties of quality assurance that are related to complexities of monitoring compliance of marine fisheries. In addition, it is apparent that property rights over the fishery seem to be an essential prerequisite for engagement in MSC, and this is one major impediment to wider uptake of the scheme in current marine fisheries, which tend to be open access. Some modifications to the current scheme may be needed if wider participation of marine fishers is to be achieved. These may include a tiered approach to certification, certification of fishers rather than fisheries, governmental facilitation to assist the latter, and greater engagement with retailers and buyers rather than individual consumers. None of these changes will occur without constructive engagement of government, retailers, and the fishing industry.     

Comanagement Practices Enhance Fisheries in Marine Protected Areas

Abstract:  Fishing activities worldwide have dramatically affected marine fish stocks and ecosystems. Marine protected areas (MPAs) with no-take zones may enhance fisheries, but empirical evidence of this is scant. We conducted a 4-year survey of fish catches around and within an MPA that was previously fully closed to fishing and then partially reopened under regulated comanaged fishing. In collaboration with the fishers and the MPA authority, we set the fishing effort and selected the gear to limit fishing impact on key fish predators, juvenile fish stage, and benthic communities and habitats. Within an adaptive comanagement framework, fishers agreed to reduce fishing effort if symptoms of overfishing were detected. We analyzed the temporal trends of catch per unit of effort (CPUE) of the whole species assemblages and CPUE of the four most valuable and frequent species observed inside the opened buffer zone and outside the MPA investigated. After the comanaged opening, CPUE first declined and then stabilized at levels more than twice that of catches obtained outside the MPA. Our results suggest that working closely with fishers can result in greater fisheries catches. Partial protection of coastal areas together with adaptive comanagement involving fishers, scientists, and managers can effectively achieve conservation and fishery management goals and benefit fishing communities and alleviate overfishing.     

Vaquita Bycatch in Mexico's Artisanal Gillnet Fisheries: Driving a Small Population to Extinction

Abstract: The world's most endangered marine cetacean, the vaquita (   Phocoena sinus ), continues to be caught in small-mesh gillnet fisheries throughout much of its range. We monitored fishing effort and incidental vaquita mortality in the upper Gulf of California, Mexico, from January 1993 to January 1995 to study the magnitude and causes of the incidental take. Of those factors studied, including net mesh size, soaktime, and geographic area, none contributed significantly to the incidental mortality rate of the vaquita, implying that the principal cause of mortality is fishing with gillnets per se . The total estimated incidental mortality caused by the fleet of El Golfo de Santa Clara was 39 vaquitas per year (95% CI = 14, 93), over 17% of the most recent estimate of population size. El Golfo de Santa Clara is one of three main ports that support gillnet fisheries throughout the range of the vaquita. Preliminary results indicate that fishing effort for San Felipe, Baja California, is comparable to that of El Golfo de Santa Clara, suggesting that this estimate of incidental mortality of vaquitas represents a minimum. We strongly recommend a complete and permanent ban on gillnets in the area. Alternative or supplemental mitigation strategies include (1) a maximum annual allowable mortality limit of vaquitas; (2) mandatory observer coverage of all boats fishing within the Upper Gulf of California and Colorado River Delta Biosphere Reserve; (3) extension of the Upper Gulf of California and Colorado River Delta Biosphere Reserve to encompass all known vaquita habitat; (4) rigorous enforcement of new and existing regulations; and (5) development of alternative sources of income for gillnet fishers.     

Bycatch of Marine Mammals in U.S. and Global Fisheries

Abstract:  Fisheries bycatch poses a significant threat to many populations of marine mammals, but there are few published estimates of the magnitude of these catches. We estimated marine mammal bycatch in U.S. fisheries from 1990 to 1999 with data taken from the stock assessment reports required by the U.S. Marine Mammal Protection Act. The mean annual bycatch of marine mammals during this period was 6215 ± 448 (SE). Bycatch of cetaceans and pinnipeds occurred in similar numbers. Most cetacean (84%) and pinniped (98%) bycatch occurred in gill-net fisheries. Marine mammal bycatch declined significantly over the decade, primarily because of a reduction in the bycatch of cetaceans. Total marine mammal bycatch was significantly lower after the implementation of take reduction measures in the latter half of the decade. We derived a crude first estimate of marine mammal bycatch in the world's fisheries by expanding U.S. bycatch with data on fleet composition from the Food and Agriculture Organization. The global bycatch of marine mammals is in the hundreds of thousands. Bycatch is likely to have significant demographic effects on many populations of marine mammals. Better data are urgently needed to fully understand the impact of these interactions.     

Catastrophic Decline in Mollusc Diversity in Eastern Tasmania and Its Concurrence with Shellfish Fisheries

Abstract:  We used historical patterns of deposition of mollusc shells to infer changes to inshore benthic assemblages in the southeastern Tasmanian region over the past 120 years. We identified and counted shells in slices embedded within 1m long ²¹⁰Pb-dated sediment cores were collected at 13 sites in water depths of 8–16 m. Declines in mollusc species richness and shell production occurred during the past century at all sites studied, with a mean decline per 5-cm sediment slice from 21 species in 1890 to 7 species in 1990 and in shell abundance from 150 to 30 individuals over the same period. The time course of decline notably corresponded with the history of the scallop dredge fishery, presumably either because scallop dredging caused general declines in populations of mollusc species or because other factors caused a catastrophic regional decline in molluscs that included scallops. As a consequence, the fishery was forced to close. Of major concern is that losses had not previously been recognized but extended throughout the 100-km coastal span of the study. Given that fishing and other anthropogenic impacts, as well as a lack of observational data, are virtually ubiquitous for the coastal zone, major recent losses in mollusc biodiversity may be globally widespread but have gone unnoticed.     

Centennial Decline in the Trophic Level of an Endangered Seabird after Fisheries Decline

Abstract:  Coastal marine ecosystems worldwide have undergone such profound transformations from overfishing that trophic interactions observed today might be artifacts of these changes. We determined whether the trophic level of an endangered seabird, the Marbled Murrelet ( Brachyramphus marmoratus ), has declined over the past 100 years after the collapse of Pacific sardine ( Sardinops sadax ) fisheries in the late 1940s and the recent declines of similar fisheries in central California. We compared stable-isotope signatures of δ¹⁵N and δ¹³C in feathers of museum specimens collected before fisheries decline with values in murrelet feathers collected recently. Values of δ¹⁵N in prebreeding diets declined significantly, 1.4‰ or 38% of a trophic level, over the past century during cool ocean conditions and by 0.5‰ during warm conditions, whereas postbreeding values of δ¹⁵N were nearly constant. The δ¹³C values in prebreeding diets declined by 0.8‰, suggesting an increased importance of krill in modern compared with historic prebreeding diets, but postbreeding diets did not change. Stable-isotope mixing models indicated that the proportion of energetically superior, high-trophic-level prey declined strongly whereas energetically poor, low-trophic-level and midtrophic-level prey increased in the prebreeding diet in cool years when murrelet reproduction was likely to be high. Decreased prey resources have caused murrelets to fish further down on the food web, appear partly responsible for poor murrelet reproduction, and may have contributed to its listing under the U.S. Endangered Species Act.     

Effects of Fisheries Closures and Gear Restrictions on Fishing Income in a Kenyan Coral Reef

Abstract: The adoption of fisheries closures and gear restrictions in the conservation of coral reefs may be limited by poor understanding of the economic profitability of competing economic uses of marine resources. Over the past 12 years, I evaluated the effects of gear regulation and fisheries closures on per person and per area incomes from fishing in coral reefs of Kenya. In two of my study areas, the use of small‐meshed beach seines was stopped after 6 years; one of these areas was next to a fishery closure. In my third study area, fishing was unregulated. Fishing yields on per capita daily wet weight basis were 20% higher after seine‐net fishing was stopped. The per person daily fishing income adjacent to the closed areas was 14 and 22% higher than the fishing income at areas with only gear restrictions before and after the seine‐net restriction, respectively. Incomes differed because larger fish were captured next to the closed area and the price per weight (kilograms) increased as fish size increased and because catches adjacent to the closure contained fish species of higher market value. Per capita incomes were 41 and 135% higher for those who fished in gear‐restricted areas and near‐closed areas, respectively, compared with those who fished areas with no restrictions. On a per unit area basis (square kilometers), differences in fishing income among the three areas were not large because fishing effort increased as the number of restrictions decreased. Changes in catch were, however, larger and often in the opposite direction expected from changes in effort alone. For example, effort declined 21% but nominal profits per square kilometer (not accounting for inflation) increased 29% near the area with gear restrictions. Gear restrictions also reduced the cost of fishing and increased the proportion of self‐employed fishers.     

Effects of River Impoundment on Ecosystem Services of Large Tropical Rivers: Embodied Energy and Market Value of Artisanal Fisheries

Abstract:  Applying the ecosystem services concept to conservation initiatives or in managing ecosystem services requires understanding how environmental impacts affect the ecology of key species or functional groups providing the services. We examined effects of river impoundments, one of the leading threats to freshwater biodiversity, on an important ecosystem service provided by large tropical rivers (i.e., artisanal fisheries). The societal and economic importance of this ecosystem service in developing countries may provide leverage to advance conservation agendas where future impoundments are being considered. We assessed impoundment effects on the energetic costs of fisheries production (embodied energy) and commercial market value of the artisanal fishery of the Paraná River, Brazil, before and after formation of Itaipu Reservoir. High-value migratory species that dominated the fishery before the impoundment was built constituted a minor component of the contemporary fishery that is based heavily on reservoir-adapted introduced species. Cascading effects of river impoundment resulted in a mismatch between embodied energy and market value: energetic costs of fisheries production increased, whereas market value decreased. This was partially attributable to changes in species functional composition but also strongly linked to species identities that affected market value as a result of consumer preferences even when species were functionally similar. Similar trends are expected in other large tropical rivers following impoundment. In addition to identifying consequences of a common anthropogenic impact on an important ecosystem service, our assessment provides insight into the sustainability of fisheries production in tropical rivers and priorities for regional biodiversity conservation .     

论湖南农村剩余劳动力转移的对策

湖南省在深入学习贯彻“十六大”精神时，落实“十六大”任务、目标及其要求的行动中，结合省内的实际情况，提出了在加快工业化进程的同时，着力解决“三农”问题，特别是农村劳动力转移问题．本文就湖南农村剩余劳动问题谈谈粗浅看法．     

Fisheries co-management and poverty alleviation in the context of the sustainable livelihoods approach: A case study in the fishing communities of Aby lagoon in Cote d'Ivoire

The study used a combination of fairly standard and often overlapping participatory tools and techniques as well as SWOT analysis in the context of the sustainable livelihoods approach (SLA), which is emerging as a potentially useful way of looking at policies and institutions to address poverty. The adoption of fisheries co-management in Aby Lagoon in Cote d'Ivoire has contributed to improving the sense of ownership, empowerment and access of fishers and other stakeholders to resources. The fishers and other stakeholders attest that the arrangement has also contributed in enhancing the sustainable livelihoods and coping mechanisms against the incidence of poverty in the communities. Fishers would like legal empowerment to enforce fisheries regulations devised by themselves and also assistance to improve their work in collection of information and adaptive research upon which to base their plans. The co-management arrangement in Aby Lagoon is still evolving. However, the study testifies to the existence of many competent actors and to a great wealth and depth of relevant experience and lessons which other actors involved in poverty reduction strategies in small-scale fishing communities can draw on.     

不同磷水平对不同种源尾叶桉的生长和养分吸收的影响

选定4个尾叶桉种源在不同的施P水平下盆栽，研究它们之间在生长和P、N吸收上的遗传差异．结果显示：施P肥对尾叶桉4个种源的生长高度、生物量积累、P及N吸收有着明显的作用，种源之间在上述指标上也有着明显的差异．在低P和高P施肥条件下，这种差异不明显，最大差异出现在土壤P的临界供给范围内（每kg土壤施15－20mg的P）．施P肥还会改变苗木地上部分和地下部分的干重之比、地上部分和地下部分的P、N吸收量之比．     

天津市水资源供求平衡战略

天津市国土规划提出了2030年经济社会发展目标,水资源的极度匮乏已成为制约天津经济增长的主要瓶颈。在传统开源节流措施的基础上,针对天津市水资源供需矛盾和分配不合理两大问题,提出了水资源供求平衡的市场化战略和需求整合战略,并对可行的政府行为进行了探讨。     

The secondary impact of nonpoint-pollution controls: A linear-programming-input/output analysis

A joint linear-programming-interindustry model is used to estimate the impact on small regional economies of nonpoint-pollution controls on agriculture. Results from the linear-programming submodel of the farm-production sector of a region are entered as final-demand changes in the “rows-only” interindustry model of the regional economy. Emphasis is placed on describing the models, the linkages between them, and on evaluating the usefulness and limitations of the modeling approach. A brief review of empirical results is also given.     

茶叶中高氯酸盐的离子色谱串联质谱分析

本研究建立了茶叶中高氯酸盐的离子色谱串联质谱分析方法.对样品前处理方法进行了优化,结果表明用20 mL高纯水振荡提取15 min,重复3次,第3次高氯酸盐浸出量仅为总浸出量的2.3％-3.0％,因此可认为茶叶经3次浸提后高氯酸盐浸出接近完全.样品萃取液选用AS20色谱柱进行分离和电喷雾串联质谱(ESI-MS/MS)检测...