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1.
《Marine Policy》2017
A coupled population dynamics and economic model is applied to the purse seine anchovy-fishery in the Gulf of Cádiz. The model simulates the population dynamics, landings and profits on a probabilistic frame. These simulations are used to assess the biological and economic consequences of an individual quota management framework enveloped by a fixed Total Allowable Catch (TAC), the present strategy used to manage this stock in the Spanish fishery. Our results accurately indicate that this strategy magnifies the biological and economic vulnerabilities associated with the exploitation of the stock, thus jeopardizing the sustainability of this fishery. Alternative strategies, such as an adaptive TAC, are explored. The results indicate that even a basic implementation of an adaptive TAC seems more favorable than the present strategy in the necessary equilibrium between profits and sustainability. This paper provides tools and an assessment that may also be useful for other small pelagic fisheries. 相似文献
2.
《Journal of Sea Research》2007,57(2-3):114-125
Many flatfish species are caught in mixed demersal trawl fisheries and managed by Total Allowable Catch (TAC). Despite decades of fisheries management, several major stocks are severely depleted. Using the Common Fisheries Policy (CFP) as an example, the failure of mixed-fisheries management is analysed by focussing on: the management system; the role of science; the role of managers and politicians; the response of fisheries to management. Failure of the CFP management could be ascribed to: incorrect management advice owing to bias in stock assessments; the tendency of politicians to set the TAC well above the recommended level; and non-compliance of the fisheries with the management regulations. We conclude that TAC management, although apparently successful in some single-species fisheries, inevitably leads to unsustainable exploitation of stocks caught in mixed demersal fisheries as it promotes discarding of over-quota catch and misreporting of catches, thereby corrupting the basis of the scientific advice and increasing the risk of stock collapse. This failure in mixed demersal fisheries has resulted in the loss of credibility of both scientists and managers, and has undermined the support of fishermen for management regulations. An approach is developed to convert the TAC system into a system that controls the total allowable effort (TAE). The approach takes account of the differences in catch efficiency between fleets as well as seasonal changes in the distribution of the target species and can also be applied in the recovery plans for rebuilding specific components of the demersal fish community, such as plaice, cod and hake. 相似文献
3.
《Marine Policy》2014
Fisheries statistics provided by the Hellenic Statistical Authority (HELSTAT) have been often criticized for unusual estimates in landings and fishing effort data and for limitations in the sampling methodology, although there is no study on the identification of these biased and misreporting estimates. In the present study the landings per species and fishing subarea, as well as the fishing effort data per fishing gear reported by HELSTAT were analysed over the period 1982–2010. The results showed abrupt changes of both the recorded species and species landings per subarea, spurious correlations of landings among different species groups and misreporting estimates in the number of fishing vessels per fishing gear. These might be likely attributed to: (a) differences of the HELSTAT administrative infrastructures at local scale, (b) changes in the sampling protocol followed by HELSTAT, (c) reporting faults made by HELSTAT, (d) fisheries restrictive measures at local basis, (e) other factors that increased the bias and the uncertainties of HELSTAT fisheries data and related to socio-economic (i.e. fuel price) and operational (i.e. spatial structure of the fisheries fleet) aspects and/or (f) to environmental changes that might possibly affected fisheries dynamics. The present study aims to the improvement of the effectiveness of the national fisheries statistics as pinpointed by Common Fisheries Policy in order to avoid imprecise and/or biased estimations about the state of the fisheries. 相似文献
4.
《Marine Policy》2017
In this paper the discard ban policy within the Portuguese fisheries sector is discussed and the opportunities and impact in the fisheries economy that arise from sales of unwanted fish under the new landing obligation are evaluated. The decadal mean price of fish (€/kg, adjusted for inflation) rose from the 1940s until the 1970s, dropping thereafter. The yearly averaged economic income estimated for discards sales between 1969 and 2009 ranged from 419345€ to 2164379€. Discard ban sales could contribute from 10% to 53% of the total landed value and 9–34% of the total catches (landings + discards). Under a discard ban policy, the fishing sector with the largest economic contribution for total discards sales would be multispecies (54%), followed by trawl (26%) and seine (20%). On average, fishing sales contributed with 0.63% to gross domestic production (GDP) between 1938 and 2009. Discard sales can increase 1.07–1.46 times more than the fish landing contribution to GDP. After 1983 the average landings/imports economic ratio was 0.28:1, which means that fish imports surpassed landings economic value 3.57 fold. The discard ban policy can create economic opportunities in the national context thus helping to revitalize some specific fisheries sectors. 相似文献
5.
《Marine Policy》2016
This study offers a brief overview of the historical development of fisheries in Madeira since 1938. Changes in food web structure in the waters around Madeira archipelago were evaluated using the mean trophic level of landings (TLm) coupled with the Fishing-in-Balance (FiB) index for the period 1979–2014. These indices were also calculated for the taxonomically aggregated data since 1938 in order to provide a rough assessment of the trophic changes and fisheries expansion in the region. The trophic level of landings has been increasing since 1938, but increased more steeply in the transition from the 1980s to the 1990s, remaining relatively stable at a high level since then. Likewise, the FiB index also increased steeply during the same time period, indicating an expansion of the fishery. Due to its oceanic and oligotrophic environment, fisheries in Madeira have become increasingly dependent on a very small number of high trophic level, migratory species, a situation which is ecologically unsustainable. A more balanced exploitation pattern, focused on a better utilization of locally available small pelagic fish, would increase sustainability of fisheries in the region, but is at present conditioned by economic constraints. 相似文献
6.
Madagascar, the world's fourth largest island, is one of the world's poorest developing countries, and its people depend heavily on marine resources for subsistence and income. Exports of these resources and foreign fishing access agreements are also important, at least from a large-scale economic perspective. In recent years, concerns have been voiced amongst local fishers and industry groups regarding the growth of the country's fishing effort. Despite these concerns, existing knowledge of the scale, composition and trends of Malagasy fisheries remains poor, and there is negligible information regarding unreported catches and illegal fishing in Madagascar's waters. Small-scale fisheries, which are often substantial in developing countries such as Madagascar, are often unreported or underestimated. Unfortunately, fisheries legislations, management plans and foreign fishing access agreements are often influenced by these incomplete data, leading to serious over-estimations of resource availability. This also appears to be the situation in Madagascar, where the reconstruction of total catches by all Malagasy fisheries sectors conducted here showed that total catches between 1950 and 2008 were twice the volume reported by national fisheries agencies. Most importantly, much of the subsistence sector is missing from official statistics, and signs of decline have already been observed in several stocks, suggesting that current levels of catches are likely to be exceeding sustainable yields. This has profound implications for the economic and ecological sustainability of fisheries, as well as food security in a country where people rely heavily on the ocean for their daily protein needs and livelihoods. 相似文献
7.
In Belgium, centralized reporting on landings of sea fisheries at the species level started in 1929. This paper summarizes the process and the results of integrating time-series, based on fragmented and disperse data sources for the period 1929–1999. The resulting database contains data by species (41), by port of landing in Belgium (4) and in ‘foreign ports,’ and by fishing area of origin (31). After quality control, total reported landings over the period 1929–2008 amounted to 3,320,518 tonnes, of which 90% was landed in the Belgian ports. After a maximum of 75,370 tonnes in 1947, annual landings declined steadily to only 26% of this peak by 2008. Currently, landings are below those achieved in 1929. The most important species in terms of landings (1929–1999) were cod (17% of all landings) and herring (16%). In terms of economic value, sole (31%) and cod (15%) were the most valuable. Close to 73% of all landings originated from 5 of the 31 fishing areas. Twenty percent of all landings (1929–1999) originated from the ‘coastal waters’, while these waters contributed nearly 60% of all landed pelagic species and 55% of all landed ‘molluscs and crustaceans’. Compared to the currently available ICES data, this local database offers advantages in temporal coverage (data from 1929 onwards), temporal scale (monthly values), and at the taxonomic level. It also provides more detailed information at the spatial scale of the southern and central North Sea, and it is the only source of historical information on landings originating from the coastal waters. Given the importance of the shallow and productive ‘Flemish banks’ as a local source of food in historical and recent times, this data is valuable for further research on the productivity of the coastal ecosystem and the local impact of fisheries. The database broadens the historical view on fisheries, underlines the decline in landings since reporting started, and serves as a basis for further (fisheries) research and policy-making in Belgium. 相似文献
8.
Niels Daan 《Journal of Sea Research》1997,37(3-4)
The Common Fisheries Policy of the European Union adopted in 1983 is primarily focused on a science-based TAC management system with fixed national quota shares. The quality of the assessments of plaice and sole, the consistency of the scientific advice, the congruency of the management decisions, and the enforcement of the regulations are reviewed over a 15-year period. The conclusion is that there have been problems at each level, with the ultimate effect that the policy has not been able to restrict fishing mortality and that the level of overexploitation has only increased. It is argued that the present TAC system has created more problems than it has resolved. Attention is drawn to the autonomic economic developments within the fishery and to the potential for managing the fishery more effectively from the cost side rather than the profit side. 相似文献
9.
Colombia has coasts on both the Atlantic and Pacific Oceans, but its marine fisheries are limited by the relatively small size of commercially important stocks. However, diverse fishery resources have traditionally been exploited by coastal communities, and industrial fisheries have grown in recent years with the intensification of tuna fishing in both oceans. The management of Colombia's fisheries has been hampered by frequent administrative changes, which has notably led to the disappearance of a part of the official landings data. We estimated total fisheries removals (reported plus discards and unreported catches) in the Colombian Atlantic and Pacific Oceans for the period 1950–2006. We used secondary sources of information to estimate missing data, and we estimated subsistence fishing and the unreported by-catches of the shrimp and tuna fisheries. We used available information on seafood prices to estimate the relative economic impact (gross revenues) of the small-scale and industrial sectors for the period 2000–2006. Our results suggest that for the period 1950–2006, the Colombian marine fisheries catches may have been almost twice the landings reported by FAO on behalf of the country (2.8 times higher in the Atlantic; 1.3 times higher in the Pacific). Although the total gross revenues of industrial fisheries were higher than those of the small-scale sector, the latter commanded higher gross revenues in the Atlantic in 2006. 相似文献
10.
Although failures and successes in fisheries management are related to decision making processes, these are rarely analyzed in detail and even less often following quantitative or semi-quantitative approaches. Herein, we study the decision making process for Chile's most important fisheries using a binary decision model. This model evaluates the probability that an annual total allowable catch (TAC) will or will not be modified by the National Fisheries Council (NFC) based on biological, economic, and social factors. We also analyze some aspects of individual voting, particularly whether the members vote against or abstain from voting on the proposed TAC and if they prioritize resource conservation objectives. Our results indicate that the risk of over exploitation for many important stocks in Chile is aggravated by failures at the decision making level: the scientifically recommended TACs for those fisheries that generate higher levels of employment and have greater economic value are normally increased. This analysis shows that the NFC has clearly prioritized short-term economic and social objectives over resource conservation goals. We discuss the need to adjust the composition and functioning of the NFC in order to ensure long-term sustainability of the fisheries. 相似文献
11.
12.
The paper reviews and summarises the literature on regulatory enforcement in fisheries. The focus is on the theoretical literature. First, some of the main contributions from the general economic literature of law enforcement are presented, along with extensions that are considered relevant to the study of fisheries law enforcement. Second, a review of the economic literature of law enforcement applied to the study of fisheries is provided. Finally, the paper presents gaps in the fisheries economics literature on regulatory enforcement and offers some possibilities for future work. 相似文献
13.
《Marine Policy》2014
Octopus vulgaris is the most important target species in Portuguese fisheries in terms of economic value, when all official and non-declared landings are considered. Around 10% of the landings in national waters come from the trawl fleet, which is both the least selective and the best documented métier in the fishery, allowing the simultaneous assessment of distribution and population structure. This study represents a first attempt to integrate different sources of information obtained at commercial trip-level, with the objective of providing a perspective of octopus population structure and relative distribution, together with information on the exploitation pattern in 2003. High-quality resolution of sequential geo-referenced data were obtained from the Portuguese Vessel Monitoring System for the fishing trips targeting octopus. Intensive fishing activity was observed inshore of two regions, one to the north of Peniche (from Cape Carvoeiro to Portuguese border) and the other between Cape St. Vicente (Sagres) and Cape St. Maria (Faro) in the South coast. Fishing trips undertaken between 39.5 and 42°N were used to provide information on volume and size distribution of landings. These show that smaller individuals (=<12 cm ML) are mainly concentrated between 40.5 and 41.5°N, whereas larger individuals (>12 cm ML) concentrate south of 41.5 and north of 40.5°N. 相似文献
14.
This paper presents an estimation of the economic effects of the Prestige oil spill in Galicia, focusing on the Death Coast fisheries and using fish landings as a market technique. Examining the evolution of landings in the Death Coast before and after the accident, the analysis reveals two opposing trends, with landings of some species increasing and those of other species diminishing. 相似文献
15.
In Puget Sound, WA (USA), rockfish (Sebastes spp.) have significantly declined in abundance, with multiple petitions to list individual species under the Endangered Species Act. In order to better understand the ecological legacy of rockfish fishing to the Puget Sound ecosystem, the local history of rockfish exploitation was reviewed, focusing on the socioeconomic forces and management decisions which influenced the trajectory of landings. Rockfish have always been harvested for human consumption in the region, but over time exploitation patterns have changed from an opportunistic subsistence activity by indigenous peoples, to a year-round target of commercial and recreational interests. Annual commercial and recreational harvests together peaked (almost 400 mt) in the early 1980s as anglers’ attitudes changed, gear technology improved, rockfish became more familiar to the market, human population increased, and agency programs promoted fisheries to sustain employment. Rockfishes were generally not managed intensely or with conservation goals in mind until the late 1980s, in part due to scientific shortcomings and a lack of resources. By the time management actions were deemed necessary, the greatest harvest had already occurred. However, the low intrinsic productivity of most rockfish species suggests that the legacy of fishing will remain for years to come. As managers strive to restore the integrity and resilience of Puget Sound, they must realize the significance of historical fishery removals to the ecosystem and use the proper social and economic incentives to drive individual behavior toward these ecosystem goals. 相似文献
16.
《Marine Policy》2013
Bycatch presents a challenge to optimizing yield in commercial fisheries, where bycatch can total more than 1 million mt per year in the United States. Yet the economic impacts of bycatch have rarely been evaluated in the scientific literature. These economic impacts largely occur from the loss of landings through (1) early closure of fisheries when catch limits of bycatch species are reached; and (2) discards of marketable catch due to regulatory requirements in the fishery. This paper illustrates the economic impacts of early closures due to bycatch in U.S. fisheries by describing past case studies, as well as evaluating the economic impacts of discarding fish in U.S. commercial fisheries. Premature closures in the fisheries reviewed resulted in potential losses ranging from $34.4 million to $453.0 million annually. Nationally, bycatch estimates in the form of regulatory discards are annually reducing the potential yield of fisheries by $427.0 million in ex-vessel revenues, and as much as $4.2 billion in seafood-related sales, $1.5 billion in income, and 64,000 jobs. Our review also shows that some of the most promising work to reduce bycatch over the last decade has been the development of gears or gear modifications, termed “conservation engineering.” 相似文献
17.
18.
《Marine Policy》2014
A multi-objective programming model has been applied to investigate conflicting goals of the Norwegian cod fisheries. The goals included in this article are economic rent and employment. Fisheries managers are confronted with the problem of how best to allocate the total allowable catch (TAC) of cod among eight vessel groups. Compromise solutions taking into account both objectives by giving them equal weights in the multi-objective programming model are calculated and discussed. This article is an extension of an earlier article in which the trade-off analysis was performed using data only for North Norway and one particular year. The present analysis includes the entire Norwegian cod fisheries and is carried out using time series data for 2003–2007, examining the annual variations of key economic and technological parameters of the cod fisheries. Based on the results from compromise programming, the article discusses management and policy implications of reallocation of the TAC by vessel groups. 相似文献
19.
《Ocean & Coastal Management》2003,46(6-7):507-526
In this article, we analyze a change in the role of federal institutions in charge of managing Mexican fisheries during the mid-1990s. During 30 years, the fishery policy in Mexico began by promoting an accelerated fishing effort. This worked through 1981, when the country recorded its highest landings (1.6 million metric tons), but landings have not increased subsequently whereas the number of fishermen has continued to increase. In 1995, the federal administration acknowledged the problems: biological over-exploitation; over-capitalization; monopoly in commercialization; failures in loan payments; failures in controlling effort; obsolete vessels and equipment; and social conflicts for the resources. In an attempt to resolve some of these problems, the administration implemented structural changes in management, science and enforcement institutions. This arrangement established goals and introduced instruments in fisheries management: it determined the biological status of most of the fisheries; applied the precautionary approach for those fully exploited or over-exploited fisheries; gave scientific advice an important role in decision making; and involved the users in decision making. This article evaluates these changes in management policy by document review, participation and interviewing management and scientists who participated in this process. We analyze, in particular, the use of science-based categorization of fisheries status, and the introduction of public participation. The interview data demonstrate that sustainable Mexican fisheries require an evolution to a more public participatory policy, in order to strengthen local institutions and fishermen over federal institutions, which should lead to a re-definition of regulation of fisheries resources. 相似文献
20.
《Marine Policy》2013
Most worldwide fish stocks are overexploited, and so exploited beyond the Maximum Sustainable Yield (MSY) and the Maximum Economic Yield (MEY). Not exploiting fisheries resources at MSY or MEY leads to the loss of production and rents from the fisheries. A large part of the EU fisheries are managed based on single species stock assessments; however, in reality, most species are caught together with other species and by different fleets. In multi-species and multi-fleet fisheries, single species assessments, and consequently MSY and MEY reference points, are often not valid, and so the catch recommendations. In this paper it is investigated the MSY and MEY estimation in multi-species and multi-fleet fisheries in comparison to single species assessments. Analyses are applied to the Bay of Biscay demersal fishery using the IAM bio-economic model. The impact of exploiting at MSY and MEY on the optimal effort allocation between fleets with different exploitation patterns and economic structures is analyzed. When accounting for the multi-species nature of the fishery, MSY landings are 0.4% to 2.7% lower than the single species simulations estimates. When accounting for the multi-fleet nature of the fishery, MSY landings are 27.2% to 30.2% higher than the single-fleet estimates. When considering the multi-fleet characteristics, MEY landings are 6.6% higher and profits are 66.5% higher than in the single-fleet simulation. Optimal effort at MEY is lower than at MSY, but when accounting for multi-fleet the optimal effort decreases for some fleets while increases for gillnetters. The results also provide an estimation of the profits at MEY (or costs of not being at MEY). Profits can be then up to 10.7 times larger than the current profits (256 million Euros compared to the current 24 million Euros). 相似文献