Global Fish Stocks Research Articles

PSIX-6 Algal oil as an alternative source of docosahexaenoic acid in feline diets

Abstract The global demand for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation by humans and their necessity in companion animal foods has raised questions related to environmental sustainability and nutrient content of fish oil. The combination of reported diminishing EPA and DHA content in fish oil and the forecasting of a significant decline in global fish stocks over the next decade make it critical to consider alternative sources of omega-3 fatty acids to reduce dependence on fish harvests. Cultured algal oil has been identified as a promising and viable alternative to fish-based oils. As such, the purpose of this study was to determine the inclusion level of algal oil in cat foods necessary to deliver the same serum concentrations of DHA provided from fish oil. Cats (n = 26) were first fed a control food formulated to avoid ingredients that contain long chain omega-3 fatty acids [ɑ-linolenic (ALA), EPA, and DHA] for 5 wk, to establish a baseline serum concentrations of these fatty acids. Cats were then randomized into two groups, and fed test foods containing either fish oil or algal oil in sequential increasing levels of DHA (0.2%, 0.4%, and 0.6%) for 5-wk periods each. Blood was analyzed for serum DHA and EPA concentrations after each of these feeding periods. A regression analysis was used to calculate a bioequivalence factor between fish oil and algal oil inclusion levels. There was no difference (P > 0.05) in intake or body weight between cats consuming diets containing algal oil or fish oil. Analysis of serum fatty acid concentrations showed that increasing fish and algal oil had no effect (P > 0.05) on serum linolenic acid, ALA, or arachidonic acid; however, increasing fish and algal oil did have an effect on DHA such that serum DHA was increased at similar rates as fish oil (P = 0.050) and algal oil (P = 0.026) levels were increased in the diet. Although increasing levels of fish and algal oil both increased serum EPA concentrations (P < 0.001), fish oil increased serum EPA to a greater extent than algal oil when fed at all levels. Overall, these data indicate that inclusion of algal oil is a good alternative dietary source of DHA, but less of EPA, and that algal oil will need to be added to the diet in higher concentrations to achieve similar serum EPA concentrations as fish oil.

Dams trigger exponential population declines of migratory fish.

The impact of dams on global migratory fish stocks is a major challenge and remains seriously underestimated. China has initiated a dozen fish rescue programs for the dams on the Yangtze River, focusing on five flagship species-Chinese sturgeon, Chinese paddlefish, Yangtze sturgeon, Chinese sucker, and Coreius guichenoti. Despite 40 years of effort, these five fishes are on the verge of extinction. Here, we propose an analytical tool that includes a framework of fish migration taxonomy and six life cycle models, the concepts of invalid stock and the dam impact coefficient, and a simplified population model. We then clarify the migration patterns and life cycles of these fishes and show that the Yangtze dams have severely disrupted the life cycle integrity of these species, causing seven types of invalid stocks and their exponential population declines. Last, we discuss six scientific misjudgments underpinning the fish rescue programs and recommend reforms to China's fish rescue strategy.

Sustainable reference points for multispecies coral reef fisheries

Sustainably managing fisheries requires regular and reliable evaluation of stock status. However, most multispecies reef fisheries around the globe tend to lack research and monitoring capacity, preventing the estimation of sustainable reference points against which stocks can be assessed. Here, combining fish biomass data for >2000 coral reefs, we estimate site-specific sustainable reference points for coral reef fisheries and use these and available catch estimates to assess the status of global coral reef fish stocks. We reveal that >50% of sites and jurisdictions with available information have stocks of conservation concern, having failed at least one fisheries sustainability benchmark. We quantify the trade-offs between biodiversity, fish length, and ecosystem functions relative to key benchmarks and highlight the ecological benefits of increasing sustainability. Our approach yields multispecies sustainable reference points for coral reef fisheries using environmental conditions, a promising means for enhancing the sustainability of the world’s coral reef fisheries.

The state of world fishery resources Expanding efforts to determine the status of global fish stocks

The state of world fishery resources Expanding efforts to determine the status of global fish stocks

A New wto Protocol on Fisheries Subsidies: Potential Implications for the South China Sea Disputes

Abstract For close to two decades, wto member countries have discussed the possibility of disciplining the practice of subsidizing fishing activities. Concrete progress has been made as there is now a consensus on eliminating certain forms of fisheries subsidies that contribute towards overcapacity, overfishing and illegal unreported and unregulated fishing. In June 2022, at the end of 12th Ministerial Conference in Geneva, Switzerland, the Agreement on Fisheries Subsidies (afs) was finally adopted. Against this backdrop, this paper will attempt to investigate the role that the afs might play in arresting the collapse of global fish stocks. Part i provides a brief background on the state of global fisheries and the role of subsidies in their depletion. Part ii discusses the key features of and contentious issues in the afs. Finally, Part iii considers the potential implications of the afs on disputed waters such as the South China Sea.

The state of world fishery resources Expanding efforts to determine the status of global fish stocks

The state of world fishery resources Expanding efforts to determine the status of global fish stocks

Recent Development of Advanced Biotechnology in the Oleaginous Fungi for Arachidonic Acid Production.

Arachidonic acid is an essential ω-6 polyunsaturated fatty acid, which plays a significant role in cardiovascular health and neurological development, leading to its wide use in the food and pharmaceutical industries. Traditionally, ARA is obtained from deep-sea fish oil. However, this source is limited by season and is depleting the already threatened global fish stocks. With the rapid development of synthetic biology in recent years, oleaginous fungi have gradually attracted increasing attention as promising microbial sources for large-scale ARA production. Numerous advanced technologies including metabolic engineering, dynamic regulation of fermentation conditions, and multiomics analysis were successfully adapted to increase ARA synthesis. This review summarizes recent advances in the bioengineering of oleaginous fungi for ARA production. Finally, perspectives for future engineering approaches are proposed to further improve the titer yield and productivity of ARA.

Which attributes of fishing opportunities are linked to sustainable fishing?

AbstractTo prevent the overfishing of marine fish populations, governments often limit fishing access through the allocation of fishing opportunities. While some studies have linked particular systems of fishing opportunities to sustainable outcomes (particularly individual transferable quota), it remains unclear whether it is the use of exclusive access (individual allocation), the use of a market (tradability), the duration of this access or the quota limits themselves that drive the sustainable outcomes. To determine which attributes of fishing opportunities are associated with sustainable fishing, we developed a novel method to systematically classify how fishing opportunities are allocated for 443 global fish stocks from 1990 to 2018 to produce the longest and most comprehensive dataset and longitudinal study of its kind. Our results revealed that quota limits and individual allocation are linked to a reduced probability of overfishing, with the most robust result for quota limits. No attributes were robustly linked to a reduced probability of overfished biomass. Whereas some previous studies have found that systems with market‐based features or strong property rights (i.e. a long duration) were linked to sustainable fishing, these benefits were found to be small or not significant once proper controls for other system attributes were introduced. These results highlight the importance of considering all attributes of institutional design in the governance of common pool resources.

Piracy as a result of IUU fishing: Challenging the causal link

ABSTRACT With declining global fish stocks, there is a growing literature on the negative impact of illegal, unreported and unregulated (IUU) fishing. While undoubtedly damaging, there is increasing analysis on the wider impact of IUU fishing, without sufficient evidence to support causal claims. This is particularly evident in the links between IUU fishing and piracy. IUU fishing was blamed for the surge of piracy in the Gulf of Aden in in the late 1990s/ early 2000s and is more recently presented as a driver for piracy in the Gulf of Guinea. In reviewing available evidence, this article finds that while there is a correlation between IUU fishing and piracy in the Gulf of Guinea, in that they both occur in the same areas, current evidence does not support a causal link between the two.

Improving estimates of the state of global fisheries depends on better data

AbstractImplementation of the United Nations Sustainable Development Goals requires assessments of the global state of fish populations. While we have reliable estimates of stock status for fish populations accounting for approximately half of recent global catch, our knowledge of the state of the majority of the world's “unassessed” fish stocks remains highly uncertain. Numerous publications have produced estimates of the global status of these unassessed fisheries, but limited quantity and quality of data along with methodological differences have produced counterintuitive and conflicting results. Here, we show that despite numerous efforts, our understanding of the status of global fish stocks remains incomplete, even when new sources of broadly available data are added. Estimates of fish populations based primarily on catch histories on average performed 25% better than a random guess. But, on average, these methods assigned fisheries to the wrong FAO status category 57% of the time. Within these broad summaries, the performance of models trained on our tested data sources varied widely across regions. Substantial improvements to estimates of the state of the world's exploited fish populations depend more on expanded collection of new information and efficient use of existing data than development of new modelling methods.

The great stagnation and environmental sustainability: A multidimensional perspective

AbstractSince the 2008/09 Great Financial Crisis, we have witnessed a prolonged period of persistent global economic slowdown termed the “Great Stagnation”. This study examines how this “new normal” is associated with critical environmental dynamics (i.e., biodiversity, water, forest, agriculture, emissions) in areas and groups with different socio‐environmental characteristics (i.e., income groups, continents, forest cover, biome, environmental performance index). Mixed results are shown. For instance, we find a deterioration in terrestrial and marine biodiversity, especially in middle‐ and high‐income countries in Africa and Europe. This includes a reduction in the global fish stock, driven by countries in Africa. In contrast, the Great Stagnation is associated with reductions in PM2.5 (lower‐ and upper mid‐income countries), CH4 emissions (upper mid‐income countries and Europe), forest loss (upper mid‐income countries and Asia), and increases in species habitat index (across most groupings). Our evidence indicates that periods of economic slowdown, such as the great stagnation, on their own cannot ensure a transition to a sustainable socio‐environmental system and may be associated with significant negative environmental effects. Managing our transition to sustainability will require concerted policy efforts across multiple environmental domains, not only on carbon emissions, and during periods of both strong and weak economic growth rates.

Scientific Methods to Understand Fish Population Dynamics and Support Sustainable Fisheries Management

Fisheries play a significant role in the livelihoods of the world population, while the dependence on fisheries is acute in developing countries. Fisheries are consequently a critical element for meeting the sustainable development (SDG) and FAO goals to reduce poverty, hunger and improve health and well-being. However, 90% of global marine fish stocks are fully or over-exploited. The amount of biologically unsustainable stocks increased from 10% in 1975 to 33% in 2015. Freshwater ecosystems are the most endangered ecosystems and freshwater fish stocks are worldwide in a state of crisis. The continuous fish stock decline indicates that the world is still far from achieving SDG 14 (Life Below Water), FAO’s Blue Growth Initiative goal and SDG 15 (Life on Land, including freshwater systems). Failure to effectively manage world fish stocks can have disastrous effects on biodiversity and the livelihoods and socio-economic conditions of millions of people. Therefore, management strategies that successfully conserve the stocks and provide optimal sustainable yields are urgently needed. However, successful management is only possible when the necessary data are obtained and decision-makers are well informed. The main problem for the management of fisheries, particularly in developing countries, is the lack of information on the past and current status of the fish stocks. Sound data collection and validation methods are, therefore, important. Stock assessment models, which support sustainable fisheries, require life history traits as input parameters. In order to provide accurate estimates of these life history traits, standardized methods for otolith preparation and validation of the rate of growth zone deposition are essential. This review aims to assist researchers and fisheries managers, working on marine and freshwater fish species, in understanding concepts and processes related to stock assessment and population dynamics. Although most examples and case studies originate from developing countries in the African continent, the review remains of great value to many other countries.

Is community-based management of small-scale fisheries in Sierra Leone the answer to their problems?

With increasing decline in global fish stocks and the possibility of extinction of many small-scale fisheries (SSF) partly because of over-fishing by large-scale industrial fishers (both licensed and unlicensed) and partly because of harmful fishing gear used by small-scale fishers themselves, researchers are focusing on alternatives to the prevailing top-down systems of fisheries management. One such alternative that is receiving attention is the community-based approach to the governance of SSF, which maintains that small-scale or artisanal fishers have a special attachment to their geographical area which makes them better managers of their fish resources. This study investigates the viability of this approach in Sierra Leone’s Tombo and Goderich fishing communities. Fieldwork was carried out during 2017 and 2019 when a total of 51 key informant (KI) and 14 telephone interviews (TI) were conducted, and 200 survey questionnaires (SQ) were distributed in the two communities. The main finding is that although several community fisheries organisations (CFO) try to manage coastal stocks, they have no power to curb industrial over-fishing, and their power to stop artisanal fishers using harmful gear is compromised by government interference and by conflicts between CFOs. The study concludes that both top-down (governmental) and bottom-up (communitarian) approaches to SSF management have flaws, and each side needs to acknowledge its flaws, and work together with the other side to eliminate them.

Menfish Classification Based on Inception_V3 Convolutional Neural Network

Due to the impact of global environmental pollution deterioration, as well as uncontrolled fishing activities. The global fish stocks are becoming more and more serious, so it is necessary to pay attention to this issue. In this paper, the characteristics of traditional fish identification methods are vast, subjective factors are strong, and the current accuracy is not good in today’s deep learning. A migration learning based on Inception_v3 network with excellent feature extraction ability is proposed. Fish recognition model This model has better recognition ability than traditional models and some simple convolutional neural networks, and further improves the accuracy of Inception_v3 for fish recognition.

Malaysian Efforts in Combating IUU Fishing: A Legal and Policy Review

Illegal, unreported and unregulated (IUU) fishing may occur on the high seas or within a national jurisdiction. Several factors were identified as contributing to the occurrence of IUU fishing activities, among which is poor governance marked by limited and overlapping enforcement by related authorities. With very limited regional enforcement bodies and the absence of a regional multilateral agreement, IUU fishing is difficult to overcome. It means that issues relating to overfishing and other fishing conflicts like foreign vessels intrusions and use of illegal fishing methods will continue to be a problem. This paper identifies the Malaysia’s legal framework governing IUU fishing, as well as relevant international and regional laws and policies. The paper also discusses the devastating effects of IUU fishing to the global fish stocks and national economy. Although the existing framework is considered comprehensive, it recommends further stringent and fair law enforcement to combat IUU fishing in Malaysia’s waters.

The security implications of fisheries

Abstract Although frequently ignored in discussion of ocean security, fisheries have had central security implications throughout history. This article re-centres fisheries issues as both a cause and effect of security conflicts, and examines the implications of this re-framing for addressing this intersection. Underlying the security concerns that arise related to fisheries is depletion of global fish stocks. When stocks are overfished or not well managed, fishing vessels move to other areas, where they are more likely to come into conflict with each other and to threaten vulnerable stocks that some populations rely on, and states will claim or defend more ocean territory. These issues are explored here with four sets of security crises that can be best understood by examining the underlying or contributing aspect of fishery depletion: conflicts over sovereignty of small maritime islands, the rise of Somali maritime piracy, the ‘fish wars’ between otherwise friendly states in the middle and latter parts of the twentieth century, and the human insecurity represented by slavery-like conditions aboard some fishing vessels. Understanding the security implications of fisheries grants new reason and new approaches—ideally multi-jurisdictional, transnational and focused on capacity-building—to better protect fisheries and prevent security threats.

ПРИРОДНО-АНТРОПОГЕННЫЕ РЕЖИМЫ В ПРОСТЫХ МОДЕЛЯХ ГЛОБАЛЬНОГО МОРСКОГО РЫБОЛОВСТВА

The study applies the system dynamics method in upgrading the World Bank’s global marine fisheries models in the interest of achieving the UN goals of sustainable development. The key variables are a global marine fish stock, its natural growth, as well as the fisheries’ effort and catch. The equations for the reproduction of the fish stock in the regimes of maximum sustainable yield, overfishing or undercatch are derived. Determined are collapse time frames in result of typical overfishing varieties. A new positive feedback loop has been proposed in regulating global marine fish stock to ensure maximum sustainable yield asymptotically.

How commercial fishing effort is managed

AbstractWild capture fisheries produce 90 million tonnes of food each year and have the potential to provide sustainable livelihoods for nearly 40 million people around the world (http://www.fao.org/3/a-i5555e.pdf). After decades of overfishing since industrialization, many global fish stocks have recovered, a change brought about through effective management. We provide a synthetic overview of three approaches that managers use to sustain stocks: regulating catch and fishing mortality, regulating effort and regulating spatial access. Within each of these approaches, we describe common restrictions, how they alter incentives to change fishing behaviour, and the resultant ecological, economic and community‐level outcomes. For each approach, we present prominent case‐studies that illustrate behaviour and the corresponding performance. These case‐studies show that sustaining target stocks requires a hard limit on fishing mortality under most conditions, but that additional measures are required to generate economic benefits. Different systems for allocation allow stakeholder communities to strike a locally acceptable balance between profitability and employment.

Establishing company level fishing revenue and profit losses from fisheries: A bottom-up approach.

A third of global fish stocks are overexploited and many are economically underperforming, resulting in potential unrealized net economic benefits of USD 51 to 83 billion annually. However, this aggregate view, while useful for global policy discussion, may obscure the view for those actors who engage at a regional level. Therefore, we develop a method to associate large companies with their fishing operations and evaluate the biological sustainability of these operations. We link current fish biomass levels and landings to the revenue streams of the companies under study to compute potentially unrealized fisheries revenues and profits at the level of individual firms. We illustrate our method using two case studies: anchoveta (Engraulis ringens; Engraulidae) in Peru and menhaden in the USA (Brevoortia patronus and B. tyrannus; Clupeidae). We demonstrate that both these fisheries could potentially increase their revenues compared to the current levels of exploitation. We estimate the net but unrealized fishery benefits for the companies under question. This information could be useful to investors and business owners who might want to be aware of the actual fisheries performance options of the companies they invest in.

Depths of uncertainty for deep-sea policy and legislation

In comparison to terrestrial and coastal ecosystems, much remains unknown about the deep sea’s ecosystems and their economic value. This is of concern on at least three fronts. First, the deep sea forms the majority of the ocean’s marine systems and contributes substantially to global fish stocks (Danovaro et al., 2017; Drazen and Sutton, 2017). Second, it is essential for the functioning of global biogeochemical cycles, and underpins the sustenance of terrestrial ecosystems and human life (Armstrong et al., 2012). Third, the deep sea faces increased pressure from human activity in the form of deep-sea mining (DSM) (The World Bank, 2016). Based upon lessons drawn from a recent systematic review and meta-analysis published in Marine Policy (Folkersen et al., 2018), this letter discusses four main directions for future research into economic valuation, policymaking and legislation pertaining to the deep sea. First, the valuation perspective adopted for policy and decision-making on deep-sea resources needs to be defined clearly. Second, strategic environmental assessments (SEAs) and environmental impact assessments (EIAs) of DSM activities need to examine the potential global environmental damage from DSM, rather than examine impacts restricted to the geographical site in which mining takes place. Third, the interdependence between anthropogenic behaviour and economic value generated by the deep sea requires further investigation. Fourth, in addition to the valuation of specific ecosystem goods and services, the ecosystem functioning of the deep sea should also be valued. Improving our understanding of the value that the deep sea provides to human societies can facilitate sustainable resource-use, effective environmental management, and prevent severe and irreversible damage to the deep sea’s ecosystems.