Ecosystem-based fisheries management requires a change to the selective fishing philosophy
01 Jan 2010-
TL;DR: In this article, the authors argue that a balanced exploitation approach might alleviate many of the ecological effects of fishing by avoiding intensive removal of particular components of the ecosystem, while still supporting sustainable fisheries.
Abstract: Globally, many fish species are overexploited, and many stocks have collapsed. This crisis, along with increasing concerns over flow-on effects on ecosystems, has caused a reevaluation of traditional fisheries management practices, and a new ecosystem-based fisheries management (EBFM) paradigm has emerged. As part of this approach, selective fishing is widely encouraged in the belief that nonselective fishing has many adverse impacts. In particular, incidental bycatch is seen as wasteful and a negative feature of fishing, and methods to reduce bycatch are implemented in many fisheries. However, recent advances in fishery science and ecology suggest that a selective approach may also result in undesirable impacts both to fisheries and marine ecosystems. Selective fishing applies one or more of the "6-S" selections: species, stock, size, sex, season, and space. However, selective fishing alters biodiversity, which in turn changes ecosystem functioning and may affect fisheries production, hindering rather than helping achieve the goals of EBFM. We argue here that a "balanced exploitation" approach might alleviate many of the ecological effects of fishing by avoiding intensive removal of particular components of the ecosystem, while still supporting sustainable fisheries. This concept may require reducing exploitation rates on certain target species or groups to protect vulnerable components of the ecosystem. Benefits to society could be maintained or even increased because a greater proportion of the entire suite of harvested species is used.
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21 Aug 2014
TL;DR: Balanced harvesting, where species or individuals are exploited in accordance with their productivity, has been proposed as a way to minimize the effects of fishing on marine fish communities and ecosystems.
Abstract: Balanced harvesting, where species or individuals are exploited in accordance with their productivity, has been proposed as a way to minimize the effects of fishing on marine fish communities and ecosystems. This calls for a thorough examination of the consequences balanced harvesting has on fish community structure and yield. We use a size- and trait-based model that resolves individual interactions through competition and predation to compare balanced harvesting with traditional selective harvesting, which protects juvenile fish from fishing. Four different exploitation patterns, generated by combining selective or unselective harvesting with balanced or unbalanced fishing, are compared. We find that unselective balanced fishing, where individuals are exploited in proportion to their productivity, produces a slightly larger total maximum sustainable yield than the other exploitation patterns and, for a given yield, the least change in the relative biomass composition of the fish community. Because fishing reduces competition, predation and cannibalism within the community, the total maximum sustainable yield is achieved at high exploitation rates. The yield from unselective balanced fishing is dominated by small individuals, whereas selective fishing produces a much higher proportion of large individuals in the yield. Although unselective balanced fishing is predicted to produce the highest total maximum sustainable yield and the lowest impact on trophic structure, it is effectively a fishery predominantly targeting small forage fish.
119 citations
Dissertation•
01 Jan 2015
TL;DR: In this paper, the authors present a list of fish species nomenclature and a collection of figures, tables, pictures, and pictures for each species, as well as an Acronyms, Abbreviations and Units.
Abstract: ...................................................................................................................................... 3 Acknowledgements...................................................................................................................... 5 List of Figures ............................................................................................................................... 8 List of Tables .............................................................................................................................. 11 List of Pictures ........................................................................................................................... 12 List of Acronyms, Abbreviations and Units .................................................................................. 13 List of Fish Species Nomenclature ............................................................................................... 15 Chapter 1: Introduction .............................................................................................................. 16 1.
9 citations
TL;DR: Wang et al. as discussed by the authors conducted a literature review to examine the magnitude and scale of unselective fisheries in China and proposed management recommendations tailored to China's needs and social contexts, including accounting for the trade-off between socioeconomic and ecological goals, contemplating impacts of un-selective fishing when implementing TAC programs, and strengthening fisheries monitoring to inform management at multiple scales.
Abstract: Understanding and managing fishery selectivity to target species and desirable size are instrumental to fisheries management. China, as the world's largest producer of marine capture fisheries, has been widely perceived to possess unselective domestic fisheries. To date, this perception remains largely anecdotal and conjectural, hindering the development of evidence-based and effective management solutions. Here, we conducted a literature review to examine the magnitude and scale of unselective fisheries in China. By collating and analysing 140 fishery-level and 807 species-level records from 66 peer-reviewed publications from 2010 to 2021, we found that primary target species were absent in 59% of fisheries, while unidentifiable low-value and juvenile mixed catch were universal. Key commercial taxa were subject to nationwide multi-gear and multispecies fisheries, each involving an average of 3.33 types of gear and accounting for less than 25% of catch individually. The ‘permissible gears’ defined by the national gear regulatory catalogue were selective over target species and caught negligible by-products, though they were used less frequently, representing only 24% of catch records. While unselective fishing can provide seafood supplies for China's large population and potentially facilitate balanced harvest, management actions are needed to control the fishing pressure on primary target species and by-product species. Amid the ongoing fisheries management reform in China, we proposed management recommendations tailored to China's needs and social contexts, including accounting for the trade-off between socio-economic and ecological goals, contemplating impacts of unselective fishing when implementing TAC programmes, and strengthening fisheries monitoring to inform management at multiple scales.
7 citations
TL;DR: In this paper, the authors evaluated the profitability, productivity and selectivity of traps used for the capture of freshwater prawn using different spacings between the laths of the traps.
Abstract: The objective of this study was to evaluate the profitability, productivity and selectivity of traps used for the capture of freshwater prawn using different spacings between the laths. This study was developed in the estuary of the Amazon River near Santana island, Amapa, Brazil. Collections were conducted using traps called “matapi”, which are cylindrical shrimp traps made with wooden slats or laths, with funnel-shaped entrances at both sides, and the spacings between the laths ranged between 1 to 10 mm in 1 mm increments. Each trap was covered with a net called a “sobrematapi”, or trap cover. The length of carapace in centimeters and the weight in grams were measured for all specimens. The shrimp were categorized into small, medium, and large size classes. Selectivity curves were used to determine selectivity for the different lath spacings. Traps with lath spacing below 7mm should be considered as being predatory because they allow for the capture of small individuals, with more than 50% of these being captured using spacings from 1 to 5mm. Despite the fact that spacings between 8 and 10mm captured lower quantities of shrimp, this enabled the capture of larger specimens with a similar total biomass yield, and this spacing is considered to be the most ecologically and economically viable. In order to minimize the capture of young shrimp without drastically affecting economic yield, it is suggested that shrimp trap lath spacings be above 6mm.
7 citations
References
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TL;DR: A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.
Abstract: Continuing population and consumption growth will mean that the global demand for food will increase for at least another 40 years. Growing competition for land, water, and energy, in addition to the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement to reduce the impact of the food system on the environment. The effects of climate change are a further threat. But the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.
9,125 citations
Dalhousie University1, University of Wyoming2, Plymouth Marine Laboratory3, Stockholm University4, Royal Swedish Academy of Sciences5, University of California, Santa Barbara6, Smithsonian Tropical Research Institute7, Scripps Institution of Oceanography8, Stanford University9, University of California, Davis10, University of British Columbia11
TL;DR: The authors analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales, concluding that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations.
Abstract: Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.
3,672 citations
TL;DR: Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions.
Abstract: Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.
2,795 citations
University of Miami1, Wildlife Conservation Society2, Marine Sciences Research Center3, Scripps Institution of Oceanography4, University of Washington5, University of Maryland Center for Environmental Science6, National Marine Fisheries Service7, University of California, Santa Cruz8, Royal School of Mines9, National Research Council10, Commonwealth Scientific and Industrial Research Organisation11
TL;DR: Pikitch et al. as discussed by the authors describe the potential benefits of implementation of ecosystem-based fishery management that, in their view, far outweigh the difficulties of making the transition from a management system based on maximizing individual species.
Abstract: Ecosystem-based fishery management (EBFM) is a new direction for fishery management, essentially reversing the order of management priorities so that management starts with the ecosystem rather than a target species. EBFM aims to sustain healthy marine ecosystems and the fisheries they support.
Pikitch
et al .
describe the potential benefits of implementation of EBFM that, in their view, far outweigh the difficulties of making the transition from a management system based on maximizing individual species.
2,011 citations
Dalhousie University1, University of Washington2, University of California, San Diego3, University of Rhode Island4, University of California, Santa Barbara5, National Oceanic and Atmospheric Administration6, Commonwealth Scientific and Industrial Research Organisation7, University of East Anglia8, Centre for Environment, Fisheries and Aquaculture Science9, Wellington Management Company10, Wildlife Conservation Society11, Stanford University12, University of New Hampshire13, University of British Columbia14
TL;DR: Current trends in world fisheries are analyzed from a fisheries and conservation perspective, finding that 63% of assessed fish stocks worldwide still require rebuilding, and even lower exploitation rates are needed to reverse the collapse of vulnerable species.
Abstract: After a long history of overexploitation, increasing efforts to restore marine ecosystems and rebuild fisheries are under way. Here, we analyze current trends from a fisheries and conservation perspective. In 5 of 10 well-studied ecosystems, the average exploitation rate has recently declined and is now at or below the rate predicted to achieve maximum sustainable yield for seven systems. Yet 63% of assessed fish stocks worldwide still require rebuilding, and even lower exploitation rates are needed to reverse the collapse of vulnerable species. Combined fisheries and conservation objectives can be achieved by merging diverse management actions, including catch restrictions, gear modification, and closed areas, depending on local context. Impacts of international fleets and the lack of alternatives to fishing complicate prospects for rebuilding fisheries in many poorer regions, highlighting the need for a global perspective on rebuilding marine resources.
2,009 citations