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2.
Arq. Ciênc. Vet. Zool. UNIPAR (Online) ; 25(1): e2503, jan-jun. 2022. tab
Artículo en Portugués | VETINDEX, LILACS | ID: biblio-1372987

RESUMEN

A demanda da população mundial por produtos aquáticos esta se incrementando, enquanto que a produção da pesca extrativa reduzindo, alcançando em muitos casos, seu máximo potencial produtivo. Como consequência, não será possível em curto prazo, sustentar o fornecimento de produtos aquáticos, direcionado a uma população que constantemente cresce e demanda pescados. O setor produtivo segue a tendência atual de outros sistemas de produção animal, os quais vêm buscando o aumento da produtividade, de maneira sustentável, do ponto de vista econômico e ambiental, requerendo, principalmente, o aporte da nutrição para contribuir com essa tendência. Os estudos com os aditivos adicionados a dieta dos animais de cativeiro é uma estratégia que tem demonstrado alto potencial para sua inclusão na aquicultura, havendo a possibilidade de um aumento nos índices produtivos e/ou melhora na qualidade do produto para o consumidor. A ractopamina é um aditivo classificado como um agonista beta-adrenérgico e seu mecanismo de ação esta associado com efeitos sobre o metabolismo dos peixes que diminuem o acúmulo de gorduras, por meio da inibição da lipogêneses e estimulo da lipólise, e por mecanismos que favorecem a síntese de proteínas muscular. Os estudos realizados até o momento comprovam que existem alterações metabólicas nos peixes, embora, não se tem encontrado, em todos os estudos, diferenças significativas nos índices zootécnicos, para assim, estabelecer seu uso na indústria. A realização de mais pesquisas é necessária para o melhor entendimento da ractopamina na alimentação dos peixes, sobretudo, no entendimento dos receptores e mecanismos de ação dos peixes.(AU)


The demand of the global population for aquatic products is increasing while the production of extractive fisheries is reducing, and, in many cases, even reaching its maximum productive potential. As a consequence, it will not be possible in the short term to sustain the supply of aquatic products aimed at a population in constant growth and in demand for fish. The productive sector follows the current trend of other animal production systems, which have been seeking to sustainably increase productivity from an economic and environmental point of view, mainly requiring the contribution of nutrition to this trend. Studies with additives to the diet of captive animals is a strategy that has shown high potential for inclusion in aquaculture, with the possibility of an increase in production rates and/or improvement in the quality of the product for the consumer. Ractopamine is an additive classified as a beta-adrenergic agonist and its mechanism of action is associated with effects on fish metabolism that reduce the accumulation of fats through the inhibition of lipogenesis and stimulation of lipolysis, and by mechanisms that favor the synthesis of muscle protein. The studies carried out so far prove that there are metabolic changes in fish, although no significant differences have been found in zootechnical indexes in order to establish its use in the industry. Further research is required for a better understanding of ractopamine in fish nutrition, especially in understanding the receptors and mechanisms of action in fish.(AU)


La demanda de la población mundial por productos acuáticos va en aumento, mientras que la producción de la pesca extractiva se reduce, alcanzando, en muchos casos, su máximo potencial productivo. Como consecuencia, no será posible en corto plazo sostener el suministro de productos acuáticos, dirigidos a una población que crece constantemente y demanda pescado. El sector productivo sigue la tendencia actual de otros sistemas de producción animal, que han venido buscando incrementar la productividad, de manera sostenible, desde el punto de vista económico y ambiental, requiriendo, principalmente, del aporte de la nutrición para contribuir a esa tendencia. Los estudios con aditivos agregados a la dieta de animales en cautiverio es una estrategia que ha mostrado un alto potencial para su inclusión en la acuicultura, con posibilidad de incremento en los índices de producción y/o mejora en la calidad del producto para el consumidor. La ractopamina es un aditivo clasificado como agonista beta-adrenérgico y su mecanismo de acción está asociado con efectos sobre el metabolismo de los peces que reducen la acumulación de grasas, a través de la inhibición de la lipogénesis y estimulación del lipólisis, y por mecanismos que favorecen la síntesis de proteínas musculares. Los estudios realizados hasta el momento prueban que existen cambios metabólicos en los peces, aunque en todos los estudios no se han encontrado diferencias significativas en los índices zootécnicos, con el fin de establecer su uso en la industria. Se necesita más investigación para comprender mejor la ractopamina en la nutrición de los peces, especialmente para comprender los receptores y los mecanismos de acción en los peces.(AU)


Asunto(s)
Animales , Agonistas Adrenérgicos beta/efectos adversos , Peces/metabolismo , Aditivos Alimentarios/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Explotaciones Pesqueras/economía
3.
Sci Rep ; 12(1): 2833, 2022 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-35181741

RESUMEN

Fisheries bycatch threatens the viability of some seabird populations and reduces fishing efficiency. Albatross bycatch in a US North Pacific tuna longline fishery has increased over the past decade and now exceeds 1000 annual captures. Seabirds interacting with this fishery reach hooks at depths up to 1 m. A branchline weight's mass and distance from the hook affect seabird catch rates. We conducted experimental fishing to compare the commercial viability of a weighted hook relative to conventional gear with weights attached 0.75 m from the hook. We used a Bayesian random effects meta-analytic regression modelling approach to estimate pooled expected species-specific log relative risk of capture on conventional versus experimental gear. There was a significant 53% (95% HDI: - 75 to - 25%) decrease in retained species' catch rates on experimental hooks, indicating an unacceptable economic cost, and no significant effect for discarded species. Using a Bayesian general linear mixed regression modelling approach, experimental hooks sank to 85 cm ca. 1.4 times (95% HDI: 1.37-1.48) faster than control hooks. Given their potential to reduce seabird catch rates, eliminate safety risks from bite-offs and facilitate robust compliance monitoring, it is a priority to find a weighted hook design with acceptable catch rates.


Asunto(s)
Aves , Conservación de los Recursos Naturales , Ecosistema , Caza/economía , Animales , Explotaciones Pesqueras/economía , Humanos , Atún
4.
Proc Natl Acad Sci U S A ; 119(2)2022 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-34992137

RESUMEN

Fisheries managers have increasingly adopted rights-based management (i.e., "catch shares" or "individual transferable quotas" [ITQs]) to address economic and biological management challenges under prior governance regimes. Despite their ability to resolve some of the symptoms of the tragedy of the commons and improve economic efficiency, catch shares remain controversial for their potentially disruptive social effects. One criticism is that the benefits of rights-based reforms are unequally distributed across vessels and between fishery participants (e.g., crew and hired captains) and that stakeholders that do not receive an allocation of harvest rights may see their remuneration decrease. Yet, empirically assessing these claims is difficult in almost all ITQs due to poor availability of longitudinal cost, earnings, and employment data. This paper evaluates these claims using vessel-level data to characterize impacts of a long-established ITQ program for Alaskan crab fisheries on the level and distribution of payments to claimant groups. We find that the share of vessel proceeds accruing to captains, crew, and vessel owners declined under the catch-share regime to make room for new payments to quota owners. Average daily payments to captains, crew, and vessel owners declined, albeit slightly, yet retained their pre-ITQ premia relative to compensation in other sectors. However, inequality in payments to workers and vessel owners declined after ITQs, as did the interseasonal volatility in compensation to workers, a measure of financial risk. Finally, we find that consolidation-induced increases in leasing costs have had little effect on workers' remuneration, but have reduced returns to vessel ownership.


Asunto(s)
Explotaciones Pesqueras/economía , Factores Socioeconómicos , Animales , Braquiuros , Peces , Humanos
5.
Sci Rep ; 12(1): 1052, 2022 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-35058546

RESUMEN

The COVID-19 pandemic provides a major opportunity to study fishing effort dynamics and to assess the response of the industry to standard and remedial actions. Knowing a fishing fleet's capacity to compensate for effort reduction (i.e., its resilience) allows differentiating governmental regulations by fleet, i.e., imposing stronger restrictions on the more resilient and weaker restrictions on the less resilient. In the present research, the response of the main fishing fleets of the Adriatic Sea to fishing hour reduction from 2015 to 2020 was measured. Fleet activity per gear type was inferred from monthly Automatic Identification System data. Pattern recognition techniques were applied to study the fishing effort trends and barycentres by gear. The beneficial effects of the lockdowns on Adriatic endangered, threatened and protected (ETP) species were also estimated. Finally, fleet effort series were examined through a stock assessment model to demonstrate that every Adriatic fishing fleet generally behaves like a stock subject to significant stress, which was particularly highlighted by the pandemic. Our findings lend support to the notion that the Adriatic fleets can be compared to predators with medium-high resilience and a generally strong impact on ETP species.


Asunto(s)
COVID-19 , Explotaciones Pesqueras/economía , Modelos Económicos , Pandemias/economía , Cuarentena/economía , SARS-CoV-2 , COVID-19/economía , COVID-19/epidemiología , COVID-19/prevención & control , Humanos
6.
PLoS One ; 16(12): e0261580, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34936680

RESUMEN

The continuous rise of the world's population has made food security a major point of the global agenda, with fisheries providing a key source of nutrition, especially in developing countries. Ensuring their health is key to maintain the availability of the resource, but its effect over accessibility is yet unclear. In this paper, we discuss the relevance of stock health for ensuring the price accessibility of the resource. A Least Square Dummy Variable panel model is proposed for bluefin tuna prices, with a biological explanatory component, and dummy variables reflecting changes in fishing trends. Both have proven to be significant to explain annual price variations, with improvements in stock health achieving price reductions.


Asunto(s)
Alimentos Marinos/economía , Animales , Comercio , Explotaciones Pesqueras/economía , Seguridad Alimentaria/economía , Humanos , Atún/fisiología
7.
PLoS One ; 16(12): e0261615, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34936682

RESUMEN

One of the most pressing challenges facing food systems in Africa is ensuring availability of a healthy and sustainable diet to 2.4 billion people by 2050. The continent has struggled with development challenges, particularly chronic food insecurity and pervasive poverty. In Africa's food systems, fish and other aquatic foods play a multifaceted role in generating income, and providing a critical source of essential micronutrients. To date, there are no estimates of investment and potential returns for domestic fish production in Africa. To contribute to policy debates about the future of fish in Africa, we applied the International Model for Policy Analysis of Agriculture Commodities and Trade (IMPACT) to explore two Pan-African scenarios for fish sector growth: a business-as-usual (BAU) scenario and a high-growth scenario for capture fisheries and aquaculture with accompanying strong gross domestic product growth (HIGH). Post-model analysis was used to estimate employment and aquaculture investment requirements for the sector in Africa. Africa's fish sector is estimated to support 20.7 million jobs in 2030, and 21.6 million by 2050 under the BAU. Approximately 2.6 people will be employed indirectly along fisheries and aquaculture value chains for every person directly employed in the fish production stage. Under the HIGH scenario, total employment in Africa's fish food system will reach 58.0 million jobs, representing 2.4% of total projected population in Africa by 2050. Aquaculture production value is estimated to achieve US$ 3.3 billion and US$ 20.4 billion per year under the BAU and HIGH scenarios by 2050, respectively. Farm-gate investment costs for the three key inputs (fish feeds, farm labor, and fish seed) to achieve the aquaculture volumes projected by 2050 are estimated at US$ 1.8 billion per year under the BAU and US$ 11.6 billion per year under the HIGH scenario. Sustained investments are critical to sustain capture fisheries and support aquaculture growth for food system transformation towards healthier diets.


Asunto(s)
Explotaciones Pesqueras/economía , África , Comercio/economía , Comercio/legislación & jurisprudencia , Empleo , Explotaciones Pesqueras/legislación & jurisprudencia , Humanos , Inversiones en Salud , Modelos Económicos
8.
Microbiol Spectr ; 9(2): e0100021, 2021 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-34523975

RESUMEN

Grass carp reovirus (GCRV), the most virulent aquareovirus, causes epidemic hemorrhagic disease and tremendous economic loss in freshwater aquaculture industry. VP56, a putative fibrin inlaying the outer surface of GCRV-II and GCRV-III, is involved in cell attachment. In the present study, we found that VP56 localizes at the early endosome, lysosome, and endoplasmic reticulum, recruits the cytoplasmic viral RNA sensor retinoic acid-inducible gene I (RIG-I) and binds to it. The interaction between VP56 and RIG-I was detected by endogenous coimmunoprecipitation (co-IP), glutathione S-transferase (GST) pulldown, and subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS) and was then confirmed by traditional co-IPs and a novel far-red mNeptune-based bimolecular fluorescence complementation system. VP56 binds to the helicase domain of RIG-I. VP56 enhances K48-linked ubiquitination of RIG-I to degrade it by the proteasomal pathway. Thus, VP56 impedes the initial immune function of RIG-I by dual mechanisms (blockade and degradation) and attenuates signaling from RIG-I recognizing viral RNA, subsequently weakening downstream signaling transduction and interferon (IFN) responses. Accordingly, host antiviral effectors are reduced, and cytopathic effects are increased. These findings were corroborated by RNA sequencing (RNA-seq) and VP56 knockdown. Finally, we found that VP56 and the major outer capsid protein VP4 bind together in the cytosol to enhance the degradation of RIG-I and more efficiently facilitate viral replication. Collectively, the results indicated that VP56 allies VP4, recruits, blocks, and degrades RIG-I, thereby attenuating IFNs and antiviral effectors to facilitate viral evasion more effectively. This study reveals a virus attacking target and an escaping strategy from host antiviral immunity for GCRV and will help understand mechanisms of infection of reoviruses. IMPORTANCE Grass carp reovirus (GCRV) fibrin VP56 and major outer capsid protein VP4 inlay and locate on the outer surface of GCRV-II and GCRV-III, which causes tremendous loss in grass carp and black carp industries. Fibrin is involved in cell attachment and plays an important role in reovirus infection. The present study identified the interaction proteins of VP56 and found that VP56 and VP4 bind to the different domains of the viral RNA sensor retinoic acid-inducible gene I (RIG-I) in grass carp to block RIG-I sensing of viral RNA and induce RIG-I degradation by the proteasomal pathway to attenuate signaling transduction, thereby suppressing interferons (IFNs) and antiviral effectors, facilitating viral replication. VP56 and VP4 bind together in the cytosol to more efficiently facilitate viral evasion. This study reveals a virus attacking a target and an escaping strategy from host antiviral immunity for GCRV and will be helpful in understanding the mechanisms of infection of reoviruses.


Asunto(s)
Proteínas de la Cápside/metabolismo , Carpas/virología , Proteína 58 DEAD Box/metabolismo , Interferones/inmunología , Reoviridae/inmunología , Animales , Proteínas de la Cápside/genética , Línea Celular , Enfermedades de los Peces/virología , Explotaciones Pesqueras/economía , Interferencia de ARN , ARN Interferente Pequeño/genética , ARN Viral/genética , RNA-Seq , Reoviridae/metabolismo , Infecciones por Reoviridae/veterinaria , Infecciones por Reoviridae/virología , Espectrometría de Masas en Tándem , Ubiquitinación
9.
PLoS One ; 16(9): e0257027, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34492086

RESUMEN

Fishing trip cost is an important element in evaluating economic performance of fisheries, assessing economic effects from fisheries management alternatives, and serving as input for ecosystem and bioeconomic modeling. However, many fisheries have limited trip-level data due to low observer coverage. This article introduces a generalized linear model (GLM) utilizing machine learning (ML) techniques to develop a modeling approach to estimate the functional forms and predict the fishing trip costs of unsampled trips. GLM with Lasso regularization and ML cross-validation of model are done simultaneously for predictor selection and evaluation of the predictive power of a model. This modeling approach is applied to estimate the trip-level fishing costs using the empirical sampled trip costs and the associated trip-level fishing operational data and vessel characteristics in the Hawaii and American Samoa longline fisheries. Using this approach to build models is particularly important when there is no strong theoretical guideline on predictor selection. Also, the modeling approach addresses the issue of skewed trip cost data and provides predictive power measurement, compared with the previous modeling efforts in trip cost estimation for the Hawaii longline fishery. As a result, fishing trip costs for all trips in the fishery can be estimated. Lastly, this study applies the estimated trip cost model to conduct an empirical analysis to evaluate the impacts on trip costs due to spatial regulations in the Hawaii longline fishery. The results show that closing the Western and Central Pacific Ocean (WCPO) could induce an average 14% increase in fishing trip costs, while the trip cost impacts of the Eastern Pacific Ocean (EPO) closures could be lower.


Asunto(s)
Conservación de los Recursos Naturales/economía , Costos y Análisis de Costo/economía , Ecosistema , Explotaciones Pesqueras/economía , Hawaii , Humanos , Modelos Lineales , Aprendizaje Automático , Océano Pacífico
10.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-34544851

RESUMEN

Across publicly owned natural resources, the practice of recovering financial compensation, commonly known as resource rent, from extractive industries influences wealth distribution and general welfare of society. Catch shares are the primary approach adopted to diminish the economically wasteful race to fish by allocating shares of fish quotas-public assets-to selected fishing firms. It is perceived that resource rent is concentrated within catch share fisheries, but there has been no systematic comparison of rent-charging practices with other extractive industries. Here, we estimate the global prevalence of catch share fisheries and compare rent recovery mechanisms (RRM) in the fishing industry with other extractive industries. We show that while catch share fisheries harvest 17.4 million tons (19% of global fisheries landings), with a value of 17.7 billion USD (17% of global fisheries landed value), rent charges occurred in only 5 of 18 countries with shares of fish quotas primarily allocated free of charge. When compared with other extractive industries, fishing is the only industry that consistently lacks RRM. While recovering resource rent for harvesting well-governed fishery resources represents a source of revenue to coastal states, which could be sustained indefinitely, overcharging the industry might impact fish supply. Different RRM occurred in extractive industries, though generally, rent-based charges can help avoid affecting deployment of capital and labor to harvest fish since they depend on the profitability of the operations. Our study could be a starting point for coastal states to consider adapting policies to the enhanced economic condition of the fishing industry under catch shares.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Explotaciones Pesqueras/estadística & datos numéricos , Peces/fisiología , Modelos Biológicos , Dinámica Poblacional , Animales , Explotaciones Pesqueras/economía , Internacionalidad
11.
PLoS One ; 16(8): e0255333, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34437562

RESUMEN

BACKGROUND: The field of behavioural economics holds several opportunities for integrated fisheries management and conservation and can help researchers and managers alike understand fisher behaviour and decision-making. As the study of the cognitive biases that influence decision-making processes, behavioural economics differentiates itself from the classical field of economics in that it does not assume strictly rational behaviour of its agents, but rather looks for all mechanisms that influence behaviour. This field offers potential applications for fisheries management, for example in relation to behavioural change, but such applications require evidence of these mechanisms applied in a fisheries context. Thus, we have developed a systematic literature review protocol focusing on the primary question: "Which behavioural economics mechanisms influence fisher behaviour?" The aim is to provide a comprehensive overview of these different mechanisms and how they have been applied in the study of fisher behaviour. METHODS AND EXPECTED OUTPUTS: The review protocol was developed in close collaboration with the International Council for the Exploration of the Sea (ICES) Working Group on Maritime Systems (WGMARS). WGMARS members were therefore considered the key stakeholders for this study, and were consulted to develop a suitable systematic review question and methodology. Three academic databases will be searched using a customized Boolean keyword search string. Research articles deemed eligible for inclusion in the systematic review are those that studied the influence of behavioural-economics mechanisms on the behaviour of marine fishers in any location, and at any scale. Insights from this literature will be collated in order to provide an overview of the relevant behavioural-economics mechanisms and actions, how effective these mechanisms are and at what scale, geographic region and in which fisheries sector they have been applied. Any fisheries management implications identified by the studies under review will also be outlined. Finally, it will be recorded whether or not ethical considerations were made in the reviewed literature, so that in the discussion it will be possible to reflect on the ethics of conducting behavioural-economics research and policy actions in a fisheries context.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Explotaciones Pesqueras/economía , Toma de Decisiones , Economía del Comportamiento , Actividades Humanas , Humanos , Revisiones Sistemáticas como Asunto
12.
Nutrients ; 13(7)2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-34371918

RESUMEN

Effective actions for the fishery and aquaculture sectors to contribute toward improving nutrition rely on an understanding of the factors influencing fish intake, particularly amongst vulnerable populations. This scoping review synthesises evidence from 33 studies in the African Great Lakes Region to examine the influence of food environments on fish acquisition and consumption. We identified only two studies that explicitly applied a food environment framework and none that linked policy conditions with the contribution of fish to diets. Economic access to fish was represented in the largest number of included studies (21 studies), followed by preferences, acceptability and desirability of fish (17 studies) and availability and physical access (14 studies). Positive perceptions of taste and low cost, relative to other animal-source foods, were drivers of fish purchases in many settings; however, limited physical and economic access were frequently identified as preventing optimal intake. In lakeside communities, fish were increasingly directed toward external markets which reduced the availability and affordability of fish for local households. Few studies considered intra-household variations in fish access according to age, gender or physiological status, which represents an important knowledge gap. There is also scope for future research on seasonal influences on fish access and the design and rigorous evaluation of programmes and policies that address one or more constraints of availability, cost, convenience and preferences.


Asunto(s)
Conducta Alimentaria , Explotaciones Pesqueras , Peces , Abastecimiento de Alimentos , Alimentos Marinos , África del Sur del Sahara , Animales , Explotaciones Pesqueras/economía , Cadena Alimentaria , Abastecimiento de Alimentos/economía , Humanos , Lagos , Valor Nutritivo , Ingesta Diaria Recomendada , Alimentos Marinos/economía , Factores Socioeconómicos
13.
PLoS One ; 16(4): e0249173, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33882056

RESUMEN

This study develops a definition of what mangrove-fisheries can encompass, incorporating a broad range of their possible characteristics. A detailed case study was conducted to develop a typology of mangrove-fishing in the Perancak Estuary, Bali, Indonesia, using interview surveys to investigate the fishing activities associated with mangroves. This case study demonstrated the complexity that a mangrove-fishery can entail, where fishing is connected to the mangrove forest by fishers of multiple sectors, functions, locations and temporal scales. Through a comparison with other mangrove-fishing communities in Bali, it also highlighted that mangrove-fisheries are variable even when in close proximity. With particular reference to this case study, a framework was developed as a flexible tool for identifying the multiple dimensions of a mangrove-fishery in a local context. Following this framework should encourage researchers and managers to look outside of the groups of fishers traditionally expected to benefit from mangrove fishing. This will enable the development of a broader definition of mangrove-fisheries in a site specific way. Identifying the full scope of fishers that contribute to or benefit from a mangrove-fishery is the first step towards building management measures that reflect the interests of groups of fishers that may otherwise remain under-represented. This is in line with international efforts for sustainability, especially in promoting small-scale fishers' access to sustainable resources under the UN Sustainable Development Goals.


Asunto(s)
Biodiversidad , Explotaciones Pesqueras/estadística & datos numéricos , Humedales , Estuarios , Explotaciones Pesqueras/economía , Humanos , Indonesia , Recursos Humanos/estadística & datos numéricos
14.
PLoS One ; 16(1): e0245255, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33471815

RESUMEN

Fish populations subject to heavy exploitation are expected to evolve over time smaller average body sizes. We introduce Stackelberg evolutionary game theory to show how fisheries management should be adjusted to mitigate the potential negative effects of such evolutionary changes. We present the game of a fisheries manager versus a fish population, where the former adjusts the harvesting rate and the net size to maximize profit, while the latter responds by evolving the size at maturation to maximize the fitness. We analyze three strategies: i) ecologically enlightened (leading to a Nash equilibrium in game-theoretic terms); ii) evolutionarily enlightened (leading to a Stackelberg equilibrium) and iii) domestication (leading to team optimum) and the corresponding outcomes for both the fisheries manager and the fish. Domestication results in the largest size for the fish and the highest profit for the manager. With the Nash approach the manager tends to adopt a high harvesting rate and a small net size that eventually leads to smaller fish. With the Stackelberg approach the manager selects a bigger net size and scales back the harvesting rate, which lead to a bigger fish size and a higher profit. Overall, our results encourage managers to take the fish evolutionary dynamics into account. Moreover, we advocate for the use of Stackelberg evolutionary game theory as a tool for providing insights into the eco-evolutionary consequences of exploiting evolving resources.


Asunto(s)
Explotaciones Pesqueras , Modelos Teóricos , Animales , Tamaño Corporal , Explotaciones Pesqueras/economía , Peces/fisiología , Teoría del Juego
15.
Proc Natl Acad Sci U S A ; 118(2)2021 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-33397723

RESUMEN

Climate shocks can reorganize the social-ecological linkages in food-producing communities, leading to a sudden loss of key products in food systems. The extent and persistence of this reorganization are difficult to observe and summarize, but are critical aspects of predicting and rapidly assessing community vulnerability to extreme events. We apply network analysis to evaluate the impact of a climate shock-an unprecedented marine heatwave-on patterns of resource use in California fishing communities, which were severely affected through closures of the Dungeness crab fishery. The climate shock significantly modified flows of users between fishery resources during the closures. These modifications were predicted by pre-shock patterns of resource use and were associated with three strategies used by fishing community member vessels to respond to the closures: temporary exit from the food system, spillover of effort from the Dungeness crab fishery into other fisheries, and spatial shifts in where crab were landed. Regional differences in resource use patterns and vessel-level responses highlighted the Dungeness crab fishery as a seasonal "gilded trap" for northern California fishing communities. We also detected disparities in climate shock response based on vessel size, with larger vessels more likely to display spatial mobility. Our study demonstrates the importance of highly connected and decentralized networks of resource use in reducing the vulnerability of human communities to climate shocks.


Asunto(s)
Cambio Climático/economía , Conservación de los Recursos Naturales/métodos , Explotaciones Pesqueras/tendencias , Animales , Braquiuros , Clima , Cambio Climático/estadística & datos numéricos , Conservación de los Recursos Naturales/tendencias , Ecosistema , Explotaciones Pesqueras/economía , Humanos , Alimentos Marinos , Mariscos , Estados Unidos
16.
Neotrop. ichthyol ; 19(3): e210097, 2021. tab, graf, mapas
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-1340237

RESUMEN

Despite Amazonia possessing the highest freshwater biodiversity on Earth, urban landing data show how huge fishing pressure is placed on only a dozen species. However, truly characterising the fishery and understanding the drivers of species selectivity is challenging, given the neglect of artisanal fishing activity, who may catch most of the Amazon's fish. We register the catch of 824 fishing trips by interviewing artisanal fishers in their rural riverside communities. We use these data to characterise the artisanal fishery of the Rio Purus, the main fish source sub-system for the Amazon's largest city (Manaus), and investigate the factors determining catch composition. Fishers caught 80 fish species, yet just four species made up over half of the harvested biomass. Urban markets appear to drive greater selectivity, with a significantly lower species diversity in commercial compared to subsistence catches. Fish catch composition varied significantly both seasonally and with geographical remoteness from Manaus. The spatial turnover in catch composition appears to be driven by urban access, with more commercially important species dominating where Manaus-based fish-buyers frequent. Our data may partially explain observed overfishing in some commercially important species, particularly as most Amazonians now live in urban areas.(AU)


Apesar da Amazônia possuir a maior biodiversidade de água doce do mundo, dados de desembarques urbanos mostram como a grande pressão da pesca é focada em apenas uma dúzia de espécies. Entretanto, caracterizar a pesca e entender as causas da seletividade das espécies é desafiador pela pesca artesanal, que pode capturar a maioria dos peixes da Amazônia, ser negligenciada. Registramos as capturas de 824 pescarias entrevistando pescadores artesanais em suas comunidades ribeirinhas. Usamos esses dados para caracterizar a pesca artesanal do rio Purus, o principal subsistema de origem do pescado para a maior cidade da Amazônia (Manaus), e investigamos os fatores que determinam a composição das capturas. Os pescadores capturaram 80 espécies de peixes, e apenas quatro representaram mais da metade da biomassa. Os mercados urbanos parecem direcionar maior seletividade, com diversidade de espécies significativamente menor nas capturas comerciais que nas de subsistência. A composição do pescado variou significativamente tanto sazonalmente quanto com o afastamento geográfico de Manaus. A substituição espacial na composição das capturas parece ser direcionada pelo acesso urbano, com espécies comercialmente importantes dominando onde os compradores de peixes de Manaus frequentam. Nossos dados podem explicar parcialmente a sobrepesca observada de algumas espécies comercialmente importantes, particularmente porque a maioria da população da Amazônia vive atualmente em áreas urbanas.(AU)


Asunto(s)
Animales , Urbanización , Biodiversidad , Explotaciones Pesqueras/economía , Zonificación de Llanuras de Inundación
18.
PLoS One ; 15(12): e0243886, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33332383

RESUMEN

Commercial fisheries globally experienced numerous and significant perturbations during the early months of the COVID-19 pandemic, affecting the livelihoods of millions of fishers worldwide. In the Northeast United States, fishers grappled with low prices and disruptions to export and domestic markets, leaving many tied to the dock, while others found ways to adapt to the changing circumstances brought about by the pandemic. This paper investigates the short-term impacts of the early months of the COVID-19 pandemic (March-June 2020) on commercial fishers in the Northeast U.S. to understand the effects of the pandemic on participation in the fishery and fishers' economic outcomes, using data collected from an online survey of 258 Northeast U.S. commercial fishers. This research also assesses characteristics of those fishers who continued fishing and their adaptive strategies to the changing circumstances. Analysis of survey responses found the majority of fishers continued fishing during the early months of the pandemic, while a significant number had stopped fishing. Nearly all reported a loss of income, largely driven by disruptions of export markets, the loss of restaurant sales, and a resulting decline in seafood prices. Landings data demonstrate that while fishing pressure in 2020 was reduced for some species, it remained on track with previous years for others. Fishers reported engaging in a number of adaptation strategies, including direct sales of seafood, switching species, and supplementing their income with government payments or other sources of income. Many fishers who had stopped fishing indicated plans to return, suggesting refraining from fishing as a short-term adaptation strategy, rather than a plan to permanently stop fishing. Despite economic losses, fishers in the Northeast U.S. demonstrated resilience in the face of the pandemic by continuing to fish and implementing other adaptation strategies rather than switching to other livelihoods.


Asunto(s)
COVID-19/economía , Conservación de los Recursos Naturales/economía , Explotaciones Pesqueras/economía , Renta , Pandemias/economía , SARS-CoV-2 , COVID-19/epidemiología , Humanos , New England
19.
Proc Natl Acad Sci U S A ; 117(47): 29419-29421, 2020 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-33139565

RESUMEN

The COVID-19 pandemic has led to environmental recovery in some ecosystems from a global "anthropause," yet such evidence for natural resources with extraction or production value (e.g., fisheries) is limited. This brief report provides a data-driven global snapshot of expert-perceived impacts of COVID-19 on inland fisheries. We distributed an online survey assessing perceptions of inland fishery pressures in June and July 2020 to basin-level inland fishery experts (i.e., identified by the Food and Agriculture Organization of the United Nations across the global North and South); 437 respondents from 79 countries addressed 93 unique hydrological basins, accounting for 82.1% of global inland fish catch. Based on the responses analyzed against extrinsic fish catch and human development index data, pandemic impacts on inland fisheries 1) add gradation to the largely positive environmental narrative of the global pandemic and 2) identify that basins of higher provisioning value are perceived to experience greater fishery pressures but may have limited compensatory capacity to mitigate COVID-19 impacts along with negative pressures already present.


Asunto(s)
COVID-19/economía , Explotaciones Pesqueras/economía , Pandemias/economía , COVID-19/epidemiología , Explotaciones Pesqueras/estadística & datos numéricos , Inseguridad Alimentaria , Humanos
20.
Nature ; 588(7836): 48-56, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33177707

RESUMEN

The threat of criminal activity in the fisheries sector has concerned the international community for a number of years. In more recent times, the presence of organized crime in fisheries has come to the fore. In 2008, the United Nations General Assembly asked all states to contribute to increasing our understanding the connection between illegal fishing and transnational organized crime at sea. Policy-makers, researchers and members of civil society are increasing their knowledge of the dynamics and destructiveness of the blue shadow economy and the role of organized crime within this economy. Anecdotal, scientific and example-based evidence of the various manifestations of organized crime in fisheries, its widespread adverse impacts on economies, societies and the environment globally and its potential security consequences is now publicly available. Here we present the current state of knowledge on organized crime in the fisheries sector. We show how the many facets of organized crime in this sector, including fraud, drug trafficking and forced labour, hinder progress towards the development of a sustainable ocean economy. With reference to worldwide promising practices, we highlight practical opportunities for action to address the problem. We emphasize the need for a shared understanding of the challenge and for the implementation of intelligence-led, skills-based cooperative law enforcement action at a global level and a community-based approach for targeting organized crime in the supply chain of organized criminal networks at a local level, facilitated by legislative frameworks and increased transparency.


Asunto(s)
Crimen/economía , Política Ambiental/economía , Política Ambiental/legislación & jurisprudencia , Explotaciones Pesqueras/economía , Océanos y Mares , Desarrollo Sostenible/economía , Desarrollo Sostenible/legislación & jurisprudencia , Animales , Tráfico de Drogas/economía , Fraude/economía , Trata de Personas/economía , Humanos , Internacionalidad , Impuestos/economía
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