Ecological limitations and appropriation of ecosystem support by shrimp farming in Colombia

Shrimp farming in mangrove areas has grown dramatically in Asia and Latin America over the past decade. As a result, demand for resources required for farming, such as feed, seed, and clean water, has increased substantially. This study focuses on semiintensive shrimp culture as practiced on the Caribbean coast of Colombia. We estimated the spatial ecosystem support that is required to produce the food inputs, nursery areas, and clean water to the shrimp farms, as well as to process wastes. We also made an estimate of the natural and human-made resources necessary to run a typical semiintensive shrimp farm. The results show that a semiintensive shrimp farm needs a spatial ecosystem support—the ecological footprint—that is 35–190 times larger than the surface area of the farm. A typical such shrimp farm appropriates about 295 J of ecological work for each joule of edible shrimp protein produced. The corresponding figure for industrial energy is 40:1. More than 80% of the ecological primary production required to feed the shrimps is derived from external ecosystems. In 1990 an area of 874–2300 km² of mangrove was required to supply shrimp postlarvae to the farms in Colombia, corresponding to a total area equivalent to about 20–50% of the country’s total mangrove area. The results were compared with similar estimates for other food production systems, particularly aquacultural ones. The comparison indicates that shrimp farming ranks as one of the most resource-intensive food production systems, characterizing it as an ecologically unsustainable throughput system. Based on the results, we discuss local, national, and regional appropriation of ecological support by the semiintensive shrimp farms. Suggestions are made for how shrimp farming could be transformed into a food production system that is less environmentally degrading and less dependent on external support areas.     

捞砂泵捞砂作业安全对策

本文针对清除油井井下积砂施工过程中循环水冲砂工艺存在的不足,提出了负压高效机械式捞砂工艺技术,并概述了该机械捞砂工艺的结构装置、工作原理,同时结合在苏丹黑格里油田现场应用过程中出现的问题,提出了捞砂泵捞砂作业的安全施工对策和措施.该研究对油田安全捞砂施工具有重要的指导意义.     

Striking a Balance between Biodiversity Conservation and Socioeconomic Viability in the Design of Marine Protected Areas

Abstract: The establishment of marine protected areas is often viewed as a conflict between conservation and fishing. We considered consumptive and nonconsumptive interests of multiple stakeholders (i.e., fishers, scuba divers, conservationists, managers, scientists) in the systematic design of a network of marine protected areas along California's central coast in the context of the Marine Life Protection Act Initiative. With advice from managers, administrators, and scientists, a representative group of stakeholders defined biodiversity conservation and socioeconomic goals that accommodated social needs and conserved marine ecosystems, consistent with legal requirements. To satisfy biodiversity goals, we targeted 11 marine habitats across 5 depth zones, areas of high species diversity, and areas containing species of special status. We minimized adverse socioeconomic impacts by minimizing negative effects on fishers. We included fine‐scale fishing data from the recreational and commercial fishing sectors across 24 fisheries. Protected areas designed with consideration of commercial and recreational fisheries reduced potential impact to the fisheries approximately 21% more than protected areas designed without consideration of fishing effort and resulted in a small increase in the total area protected (approximately 3.4%). We incorporated confidential fishing data without revealing the identity of specific fisheries or individual fishing grounds. We sited a portion of the protected areas near land parks, marine laboratories, and scientific monitoring sites to address nonconsumptive socioeconomic goals. Our results show that a stakeholder‐driven design process can use systematic conservation‐planning methods to successfully produce options for network design that satisfy multiple conservation and socioeconomic objectives. Marine protected areas that incorporate multiple stakeholder interests without compromising biodiversity conservation goals are more likely to protect marine ecosystems.     

Organotins in North Sea brown shrimp (Crangon crangon L.) after implementation of the TBT ban

The organotin (OT) compounds tributyltin (TBT) and triphenyltin (TPhT) are potent biocides that have been used ubiquitously in antifouling paints and pesticides since the mid-1970s. These biocides are extremely toxic to marine life, particularly marine gastropod populations. The European Union therefore took measures to reduce the use of TBT-based antifouling paints on ships and ultimately banned these paints in 2003. Despite sufficient data on OT concentrations in marine gastropods, data are scarce for other species such as the North Sea brown shrimp (Crangon crangon), a dominant crustacean species in North Sea inshore benthic communities. The present study provides the first spatial overview of OT concentrations in North Sea brown shrimp. We have compared these data with historical concentrations in shrimp as well as with sediment concentrations. We have also addressed the effect on the shrimp stock and any human health risks associated with the OT concentrations found. TBT and TPhT in shrimp tail muscle ranged from 4 to 124 and from 1 to 24 μg kg⁻¹ DW, respectively. High levels are accumulated in estuarine areas and are clearly related with sediment concentrations (biota-sediment accumulation factor ∼10). Levels have decreased approximately 10-fold since the ban took effect, coinciding with a recovery of the shrimp stock after 30 years of gradual regression. Furthermore, the OT levels found in brown shrimp no longer present a human health risk.     

我国渔港经济区发展现状、问题及对策探讨

发展渔港经济区对调整渔业产业结构,促进渔业增效和渔民增收,激活渔区经济,加快海洋经济步伐,全面建设小康社会具有重要的意义。对我国渔港经济区的发展现状、特点进行了梳理,在分析目前存在问题的基础上,提出了建设渔港经济区的相关建议,以期对相关决策部门制定战略提供有益参考。     

Reducing commercial fishing deck hazards with engineering solutions for winch design

INTRODUCTION: The majority (67%) of hospitalized injuries among Alaska commercial fishermen are associated with deck machinery. This paper describes the "Prevention Through Design" process to mitigate one serious machinery entanglement hazard posed by a capstan deck winch. METHODS: After observing that the capstan winch provides no entanglement protection and the hydraulic controls are usually out of reach of the entangled person, NIOSH personnel met with fishermen and winch manufacturers to discuss various design solutions to mitigate these hazards. RESULTS: An emergency-stop ("e-stop") system was developed that incorporated a momentary contact button that when pushed, switches a safety-relay that de-energizes the solenoid of an electro-hydraulic valve stopping the rotating winch. The vessel owners that had the e-stop installed enthusiastically recommend it to other fishermen. NIOSH entered into a Proprietary Technology Licensing Agreement with a company to develop the system for commercial use. CONCLUSIONS: This is an example of a practical engineering control that effectively protects workers from a hazardous piece of equipment by preventing injuries due to entanglement. This solution could reduce these types of debilitating injuries and fatalities in this industry.     

基于广义可加模型和案例推理的东南太平洋智利竹筴鱼中心渔场预报

根据2001～2008年我国渔船在东南太平洋海域的智利竹筴鱼生产统计数据以及同期卫星遥感数据反演的海表温度、叶绿素浓度、海表温度梯度等数据,利用广义可加模型定量分析了智利外海竹筴鱼资源分布同环境因子的关系。根据GAM模型的研究结果,确定海表温度作为竹筴鱼中心渔场预报指标。利用案例推理方法,通过三级相似检索对智利竹筴鱼中心渔场进行预报。试验性预报实例的结果与渔船实际作业情况比较表明,预报精度达到68%,能一定程度上反映竹筴鱼资源的分布。     

Major shifts in Amazon wildlife populations from recent intensification of floods and drought

In the western Amazon Basin, recent intensification of river‐level cycles has increased flooding during the wet seasons and decreased precipitation during the dry season. Greater than normal floods occurred in 2009 and in all years from 2011 to 2015 during high‐water seasons, and a drought occurred during the 2010 low‐water season. During these years, we surveyed populations of terrestrial, arboreal, and aquatic wildlife in a seasonally flooded Amazonian forest in the Loreto region of Peru (99,780 km²) to study the effects of intensification of natural climatic fluctuations on wildlife populations and in turn effects on resource use by local people. Shifts in fish and terrestrial mammal populations occurred during consecutive years of high floods and the drought of 2010. As floods intensified, terrestrial mammal populations decreased by 95%. Fish, waterfowl, and otter (Pteronura brasiliensis) abundances increased during years of intensive floods, whereas river dolphin and caiman populations had stable abundances. Arboreal species, including, macaws, game birds, primates, felids, and other arboreal mammals had stable populations and were not affected directly by high floods. The drought of 2010 had the opposite effect: fish, waterfowl, and dolphin populations decreased, and populations of terrestrial and arboreal species remained stable. Ungulates and large rodents are important sources of food and income for local people, and large declines in these animals has shifted resource use of people living in the flooded forests away from hunting to a greater reliance on fish.     

Use of Fully Biodegradable Panels to Reduce Derelict Pot Threats to Marine Fauna

Fishing pots (i.e., traps) are designed to catch fish or crustaceans and are used globally. Lost pots are a concern for a variety of fisheries, and there are reports that 10 – 70% of deployed pots are lost annually. Derelict fishing pots can be a source of mortality for target and bycatch species for several years. Because continual removal of derelict gear can be impractical over large spatial extents, modifications are needed to disarm gear once it is lost. We tested a fully biodegradable panel with a cull or escape ring designed for placement on the sides of a crab pot that completely degrades into environmentally neutral constituents after approximately 1 year. This panel is relatively inexpensive, easy to install, and can be used in multiple fisheries. We used the blue crab (Callinectes sapidus) fishery as a test case because it is a large pot fishery and blue crab pots are similar to traps used in other pot fisheries. We had commercial fishers deploy pots with panels alongside standard pots in Chesapeake Bay (U.S.A.) to assess potential effects of our experimental pots on blue crab catch. We compared the number, biomass, and size of crabs captured between standard and experimental pots and evaluated differences in catch over a crabbing season (March–November) at five locations. There was no evidence that biodegradable panels adversely affected catch. In all locations and time periods, legal catches were comparable in abundance, biomass, and size between experimental and standard pots. Properly designed biodegradable panels appear to be a viable solution to mitigate adverse effects of derelict pots. Uso de Paneles Completamente Biodegradables para Reducir las Amenazas de Vasijas Abandonadas para la Fauna Marina     

Understanding Anglers’ Preferences for Fishing Tournament Characteristics and Policies

Saltwater fishing tournaments in the United States are generally not regulated nor are there different fishing regulations for tournament and nontournament anglers. Although much is known about those who participate in fishing tournaments in terms of their fishing motivations, attitudes, and characteristics, much less is known at the angler population level regarding their preferences for tournament opportunities. Using a stated preference choice model with hypothetical scenarios to simulate participation choices and understand preferences, study objectives were to identify angler preferences for various types of tournament fishing “products.” Four tournament policy characteristics were investigated: promotion of catch and release, bait restrictions, whether a percentage of the tournament entrance fee should go to support fishery management activities, and whether a tournament should be a nonprofit or profit-making venture. Three expectation attributes were inserted: tournament size, trip cost per day, and whether a tournament is family friendly. We sent seven different versions of the mail questionnaire to 1,633 anglers. Of 795 returns, 648 were used for estimating conditional logit models. Analysis indicated that a scenario with no management interventions was not most preferred. Anglers most preferred a conservation-oriented option that introduced additional management measures. Overall, scenarios with management interventions were more favored than the status quo situation (with no management interventions). Although respondents showed reluctance to adopt other management-related options, results generally indicated they were increasingly concerned with sustainability of fish stocks and potential conflicts between tournament and nontournament users and preferred tournament products that reflect these concerns.