Challenges of Fishery Biology and Fish Population Dynamics in Fisheries Management

1. Introduction

More than 30,000 species of bony fishes, sharks and rays have been identified worldwide [1], inhabiting freshwater, marine, and estuarine environments. Together with crustaceans and mollusks, some of them constitute key fishery resources, with global production reaching a record of 185.4 million tons in 2024 [2]. Despite their importance, knowledge of their biology and population dynamics remains limited.

In developed countries, between 10% and 50% of fish stocks are subject to assessment, while in developing countries, this proportion is typically between 5% and 20% [3]. Large pelagic marine stocks targeted by industrial fisheries have been relatively well monitored and managed for decades [4]. In contrast, small-scale fisheries—particularly those targeting low-value species—have received limited attention and fewer resources for data collection and research [3,5,6], despite contributing at least 40% of global fishery catches (37.3 million tons) and 44% of their economic value (USD 77.2 billion) [7] and providing a source of livelihood and food globally [6].

As a result, most global fish stocks are considered data-limited [3], making their assessment particularly challenging. This difficulty is compounded by the multispecies nature of many small-scale fisheries and their complex socio-ecological dynamics.

It is a paradox that 90% of fishers are from small-scale fisheries in the Global South, while 90% of fisheries’ scientists are focusing their research on commercial stock in the Global North. The lack of quantitative data, as well as the high degree of underreporting, is a particularly acute problem when making meaningful suggestions for research and management [6].

Fishery resources are a source of nutritional security, as well as employment—with 62 million fishermen alone in primary production [2,8]—and provide economic support for the fishing industry and a large number of fishing communities, especially those in coastal areas and inland waters, with an estimated total population of 600 million [8]. However, these fishery resources continue to be exploited based on incomplete knowledge.. The lack of information on biology and population dynamics for these fisheries jeopardizes sustainability as management decisions are made without sufficient scientific support.

The importance of fisheries and aquaculture as sources of food security is undeniable. Basurto et al. [7] estimated that small-scale fisheries provide 2.3 billion people with, on average, 20% of their dietary intake of six key micronutrients essential for human health. Barreto et al. [9] acknowledge the contribution of bycatches in trawl fishing not only as an economic supplement to the main activities but also as a means of supporting food security in coastal communities. Only recently has the idea of fish providing a means of food security and nutrition gained attention as a valid and potentially more effective and inclusive starting point for managing fisheries compared to solely considering economic performance [6], with hunger and malnutrition affecting more than 40% of the global population [2].

Historically, fishery assessments have emphasized the biological and ecological aspects, but a holistic approach recognizing the sector’s intricate dynamics, from harvest to the end-user, is essential to overcome challenges like overfishing, economic losses [10] and food security in the face of the projected increase in the global population to 8.5 billion people by 2030 [8] and 9.7 billion people by 2050 [2].

Therefore, fisheries worldwide, and small-scale fisheries in particular, whose management and conservation are based on knowledge of fishes’ biology and population dynamics, face major challenges, several of which are highlighted in the following section.

1.1. Timely Assessment of Fish Stocks to Support Their Sustainable Use

The large amount of fishing resources around the world, and the limited human and financial resources available to assess them, have led to delays in the availability of scientific information to address problems faced by fisheries in a timely manner and to control the fish population, restore degraded fisheries and prevent overexploitation.

In stock evaluations, approaches focusing on maximizing production and revenues from fish populations are widely used in single-species fisheries, but in small-scale multispecies fisheries this is inapplicable because of costs, technical conflicts and data limitations [6]. The proportion of marine fish stocks exploited within biologically sustainable levels decreased to 62.3% in 2021 [2], which means a great commitment is needed to improve this.

The sustainable management of fish stocks is severely challenged by the insufficient catch, survey, and other biological data available for most worldwide fish stocks, making it difficult to estimate current abundance and productivity using traditional stock assessment methods [3]. The governance of fish stocks is the bedrock of aquatic food systems, both now and in the future. While small fish stocks are at least ten times more abundant and productive than large fish, and generally less exploited, better research and monitoring of them is needed. They comprise approximately half of all global landings and this proportion is increasing in the small-scale fisheries sector [6].

To address all of these challenges, it is essential to know the status of exploited fish stocks through demographic parameters such as growth, reproduction, recruitment, natural and fishing mortality, available biomass, spawning biomass, and bioeconomic yield. It is also important to understand the life cycles of exploited resources, their distribution and abundance, fishing efforts, and long-term catch trends, as well as with fluctuating environmental factors and climate variability. All of this can be achieved through the application of classical methods of studying fisheries’ biology, population dynamics, and population ecology, and an analysis of the time series of catches and environmental parameters. Recently, given the limited availability of sufficient data on some fishery resources and the urgent need to establish fisheries’ management strategies, the need to address poor data modeling has become increasingly relevant.

Three bibliometrics analyses of research trends whose results appear to be replicated to a greater or lesser extent in other countries indicate the following.

In Brazil, while significant advancements have been made in understanding the growth, reproduction, distribution and life cycles of commercially important species, there remains a notable knowledge gap regarding species of no commercial value. Addressing these gaps is crucial for a comprehensive ecosystem-based management approach, ensuring sustainable fisheries and informed stock assessments [11].

In Africa, a decline in research on marine fishing has been found. Key themes are not prioritized in current governance pathways. Limited marine sociological research has been conducted and there is limited funding to transdisciplinary research. Therefore, it is necessary to focus on understanding socio-ecological complexities [12].

Fisheries’ value chain research has seen consistent growth since 2002, with a notable increase between 2019 and 2020. The USA is a key contributor to this research, with collaborations involving Norway, the UK, and Australia. Most of this research focuses on industry challenges and governance frameworks, addressing the pandemic’s impacts on fisheries and strategies for enhancing resilience in the sector. The second theme centers on exploring how economic dynamics and policy frameworks interact to enable effective governance and sustainable market operations in fisheries. Socioeconomic aspects, by-product utilization, and the valorization of fish waste remain underdeveloped. Research focusing on small-scale fisheries, livelihoods and food security occupy a critical role in marine socioeconomics [10].

The empirical knowledge held by fishermen and local communities is invaluable and extremely useful for accelerating our understanding of the dynamics of fishery resources; therefore, this should be considered in the evaluations. Furthermore, involving the fishermen and the fishing community in the collection and analysis of data and in developing proposals that support the management of their fishery resources could increase their commitment to complying with regulations on fisheries. The fishing sector can be strengthened through the establishment of participatory governance structures.

Whatever mechanism is used to generate information on fishery resources, it is essential to make it available to decision-makers in a timely manner. Keep in mind that managers must make decisions even in the absence of data and/or adequate scientific advice [3]; therefore, it is better to have some information than none.

1.2. Understanding the Dynamic Response of Fishery Resources to Regulations

The conventional regulatory framework for various fisheries around the world is based on the establishment of fishing areas, catch quotas, restrictions on the type, operation, and characteristics of the fishing gear used, minimum allowable catch sizes, mesh sizes for nets, limits on fishing efforts and the number of traps used, closed seasons, fishing refuges, etc. The theoretical aim of these regulatory measures is to maximize production and economic returns by catching only a fraction of the fish population, so that the uncaught portion of the population, which remains in its habitat—whether freshwater, estuarine, or marine—is able to replenish the population removed by fishing, thereby ensuring sustainability.

This theory, developed in industrial single-species marine fisheries, is largely inapplicable in small-scale fisheries, primarily because of their multispecies nature and because of the high costs, technical conflicts and data limitations this represents. The theoretical foundation for conventional single-species legislation in a multispecies framework is increasingly being challenged [13,14]. From an ecosystem perspective, the fishing pressure on most small species is only a fraction of the pressure on large fish species. There is an urgent need to examine and evaluate fishing patterns from an ecosystem perspective and revise the legislation where necessary [6].

In many artisanal fisheries, fishing pressure has shifted from large to small fish, as evidenced by catch composition and changes in fishing patterns [6]. However, these shifts are occurring without a scientific assessment of the pressures, ecosystem effects, or governance, and conflict with existing regulations on fishing gear and nets in many regions. These fisheries operate outside the scope of current fisheries legislation, which focuses primarily on protecting juveniles of larger species. Consequently, many fishing techniques are considered illegal, which can lead to conflicts between fishers and managers [5,6,15,16,17].

The greatest threats for inland fisheries are not from fishing, but from anthropogenic habitat destruction and land use changes. Most inland fisheries are dependent on small waterbodies, floodplains, lakes, swamps, and associated agriculture systems (rice fields), which have seasonal boom-and-bust cycles depending on rainfall and floods [18]. Water abstractions, river regulations, dam construction and land runoff (pollution and eutrophication) are much more detrimental to these fisheries than fishing. This is another example of why conventional concepts of management and regulations, inherited from the context of large-scale marine fisheries, are inappropriate and why reconsiderations should include a much more holistic perspective based on rivers and lake basins [6].

The FAO recognizes that data collection systems should be established for fisheries, including bioecological, social, cultural, and economic information relevant to decision-making that ensures the sustainability of ecosystems, including the assessment of stocks in a transparent manner [19]. A management strategy based on benchmarks and reference points, such as the Maximum Sustainable Yield (MSY), is meaningless in the absence of data on the fleet structure, fish abundance, fishing mortality, and regulations [3]. Maximizing economic value while maintaining the ecosystem structure would require a reduction in fishing efforts, with a high social cost for fishing communities with limited alternative sources of livelihood [20]. However, most of these approaches require specific ecological, social and economic reference points for each context and fishery, which makes them costly.

Much further research is required on the effects of various management strategies on fishery resources. In several fisheries, particularly small-scale ones, the impact of reducing the biomass of target and bycatch species on the ecosystem and the resulting disruption to food webs is unknown. Information gaps also exist regarding biodiversity loss and its effect on ecosystem structure and function, as well as the specific impact of various anthropogenic activities on fishery resources. This information is crucial for complementing conventional fisheries regulation with an ecosystem-based approach.

The implementation of management practices and policies to improve accessibility and consumption patterns, especially in small-scale fisheries, is essential to ensure food security for the billions of people living in coastal communities [21].

1.3. Understanding the Dynamic Response of Fishery Resources to the Effects of Climate Variability and Climate Change

Climate variability has profound effects on the distribution and abundance of fish population through (a) ocean temperature and currents that influence their movement and migration, (b) precipitation that carries terrestrial sediments and organic matter and alters salinity, and (c) winds that generate tides and upwellings, oxygenate the water, and generally determine the productivity of marine ecosystems. Changes in ocean temperature and chemistry affect the physiology, growth, and reproduction of fish and invertebrates [22,23]. Various climate variation phenomena are recognized, such as El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), also known as the Interdecadal Pacific Oscillation (IPO), the Indian Ocean Dipole (IOD), the Southern Annular Mode (SAM), the North Atlantic Oscillation (NAO), the North Pacific Gyre Oscillation (NPGO), the Atlantic Multidecadal Oscillation (AMO), and the Arctic Oscillation (AO), whose effects on oceanic fish populations could help predict the impact of climate change [24].

There is evidence that fish populations have altered their geographic distribution in response to rising ocean temperatures caused by climate change, leading to a decline in fish biomass and economic losses for the fishing industry and consumers of seafood, affecting fishing opportunities, and these effects are expected to increase [25,26]. It has also been observed that rising levels of carbon dioxide (CO₂) in the atmosphere have caused changes in the physiology of organisms, life-history traits, and the population dynamics of natural marine resources in general [27]. Xu et al. [28] conducted research on the trends, challenges and gaps, identifying geographical disparities, knowledge inequality issues with data quality and management, and inadequate capacity to adapt to climate change at the global level.

Tai et al. [27] indicate that accurate projections of the impacts of ocean acidification and global change on marine fisheries require interdisciplinary integration to determine how multiple environmental drivers interact at various levels of biological organization, and they recommend evaluating fisheries’ capacity to adapt to and mitigate the impacts of global change alongside biological models to better inform management decisions and conservation efforts.

The effects of climate change on both coastal and oceanic fisheries have been assessed; however, in both cases, there are gaps in the information and challenges remain. For example, Heck et al. [29], who analyzed variations in the risk faced by fishing-dependent coastal nations due to ocean acidification, as well as changes in sea surface temperature, sea-level rise, and storms, found multiple interregional differences. They therefore indicate that it is essential to have specific information on how each fishery resource is responding to the various effects of climate change. Future research should be conducted with this perspective in mind. This poses a major challenge given the inequality in the economic and human resources available for research between developed and developing countries, and between industrial and small-scale fisheries.

Recently, Koerner et al. [26] acknowledged the lack of consistent and relevant global-scale data for assessing the risks of climate change to fisheries. In an attempt to assess these in large-scale marine fisheries, they combined projections of fish stock distribution changes and marine biomass with vulnerability indicators for fisheries, and found that tuna and marlin fisheries face the highest risk of management failure due to their high stock changes and greater governance vulnerability, followed by small pelagic and demersal fisheries. They also analyzed global fisheries with high management performance (MSC-certified), suggesting that the risk may be higher among fisheries without MSC certification. This poses a major challenge, as most fisheries worldwide lack basic biological and fisheries data, as well as the ecological, socioeconomic, and legal information required to qualify for certification.

Therefore, progress must be made to generate specific information for each fishery resource in every country—with international collaboration on shared resources— to respond in a timely manner to the impact of climate change.

1.4. Understanding the Adaptation and Resilience Mechanisms of Fishery Resources in the Face of Ongoing Disturbances Caused by Anthropogenic Activities

The continuous growth of the human population and the activities it undertakes for its well-being and survival pose a serious threat to fishing, especially in coastal areas, where large human communities have settled. To meet their needs for housing, food, and recreation, these communities engage in land-use changes, leading to deforestation, loss of mangrove cover, loss of biodiversity, overfishing, air, water, and soil pollution from organic and inorganic waste, the discharge of wastewater into the sea, plastic waste, oil spills, sediment accumulation and impacts due to the construction of breakwaters and jetties, eutrophication, etc. All these cause alterations in the habitat of fishery resources and pose a threat to biodiversity.

In the various freshwater and marine environments that fish populations inhabit—whether reservoirs, rivers, estuaries, coastal lagoons, reefs, the ocean, etc.,—fish have developed different mechanisms to adapt to changes—whether natural or human-induced—and ensure their survival, thereby demonstrating resilience. These include behavioral, physiological and morphological adaptations, and even evolutionary changes, depending on the duration, diversity, frequency, and intensity of the pressure to which they are subjected. Some species demonstrate an extraordinary capacity to withstand and recover, depending on the stressor; however, when rapid and drastic changes occur—such as direct habitat destruction and climate change—the resilience of many species is overwhelmed, and their ability to recover will depend solely on the reduction in human pressure.

To be able to identify appropriate measures for the conservation and sustainable use of aquatic resources, it is essential to understand the impact of environmental and human factors on fish stocks and yields, and how they might change [30]. In this regard, there are many information gaps that must be addressed, since each fishery resource responds differently to the threats it faces, depending on the type, intensity, and duration of the impact. Therefore, it is essential to understand the physiological, morphological, and behavioral responses of every single fish and invertebrate species to each threat in their environment. Specific knowledge of fishery biology and the population dynamics for each species plays a crucial role in this endeavor, and this goal will be achieved as new knowledge is generated.

Since 2013, Cheung et al. [22] have been warning that ocean warming has affected global fisheries over the past four decades, encouraging the development of adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions. Heck et al. [29] also warned that some regions might experience an increase in conflicts over fishery resources due to the uneven effects of climate change on fisheries, highlighting the need for strategies that enhance these countries’ ability to cope with any type of impact, in addition to specific risk-reduction strategies. Yin et al. [31] state that both swift actions in carbon emission mitigation and climate-adaptive fisheries management reforms are imperative to reduce losses for fisheries and ensure ecological and socio-economic resilience.

1.5. Understanding the Dynamic Response of Fishery Resources to Supply–Demand Relationships in a Fluctuating Market: Traceability and Innovation

Fish and fishery products remain some of the most traded food commodities in the world. In 2018, 67 million tons, or 38% of total fisheries’ and aquaculture production, were traded internationally [32]. In 2022, more than 230 countries and territories participated in this trade, generating a record 195 billion USD [8], meaning that about 78% of fish and fishery products are subject to competition from international trade [32]. Women make visible contributions to food and livelihood security in all regions of the world, catching roughly 2.9 million (±835,000) tons of marine fish and invertebrates per year. The landed value of the catch by women is estimated at USD 5.6 billion (±1.5 billion), with an economic impact of USD 14.8 billion per year (±4 billion) [33].

On the other hand, the blue transformation roadmap 2022–2030 recognizes the need to support the 2030 Agenda through a transformation to more efficient, inclusive, resilient and sustainable aquatic food systems to improve production, nutrition, the environment and quality of life, leaving no one behind [8].

When designing fisheries resource management policies, economic and social variables must be incorporated to describe the prevailing market structure, assess the level of economic efficiency, and examine the social aspects of production [34]. Socioeconomic issues, including market demand and food security, have broad relevance and play an important role in various areas of research [10]. The lack of socioeconomic data is hindering effective resource management and the identification of appropriate market-based solutions to improve fishermen’s livelihoods [35].

Given these circumstances, fisheries scientists are required to generate scientific information that helps to understand not only the dynamics of fish populations but also the dynamics of human populations and the processes involved in the seafood value chain, to help ensure that fisheries remain sustainable. Contributing to this effort presents significant challenges. To ensure a sufficient supply of fish for the market and consumer demand, you should know the diversity, abundance, availability, accessibility, variability, stability, and quality of the fishery resources, as well as the affordability for consumers, in addition to identifying the strengths and weaknesses of the value chain’s interactions with producers, processors, traders, middlemen, retailers, wholesalers, consumers and other actors. Value chains for capture and culture fisheries differ from fish to fish and from country to country, and frequently within regions [32], which highlights the need for further research to fill in the gaps.

Issues such as the use of fishery by-products have not been sufficiently studied and require further development [10]. Identifying the natural resources and services available to a community is necessary to fully harness its commercial potential and to facilitate economic diversification [36]. Technological designs and innovations—particularly rural innovations aimed at low-income communities—need to be developed and implemented to help improve the economic returns of the fishery industry, offer an alternative income to rural communities and strengthen socio-economic systems. Investment in technology, professional development, and the promotion of the best management practices have a direct impact on product quality and increase product value [9]; therefore, these actions should be promoted.

Traceability—the ability to track the history of a fishery product from catch and processing through to its distribution and the location of the end-consumer—plays a key role in market access, as both food safety and legal origin underpin international trade. This issue has become increasingly important recently given the rapid growth in international trade among developing countries compared to developed countries [32]. The increase in the media coverage of environmental, social, and legal issues related to fish has led to significant concern among shareholders, with potential repercussions for brand value, presenting challenges regarding companies’ corporate social responsibility initiatives [32].

Furthermore, growing interest in the blue economy is accelerating industrial fishing in many parts of the world. This intensification is affecting the livelihoods of small-scale fishers, as it depletes local fish stocks and undermines market systems and positions in the value chain [37]. Industrialized, capital-intensive fishing has disrupted the economic and social organization of local fishing communities, affecting incomes, causing conflicts, social exclusion, and disconnection, and jeopardizing women’s social identity. In Ghana, the coastal fishing sector has limited capacity to adapt to these cumulative impacts and disruptions [37]. Identifying value-added opportunities for fishery resources and creating new value chains are emerging priorities for supporting the economic development of the most vulnerable coastal communities, which depend on the blue bio-trade, and must focus on sustainability in the ocean [36]. As innovation and globalization accelerate marine transformation, research into coastal fishing livelihoods is becoming crucial to understanding their social, economic, and ecological effects [37].

2. Synopsis for Special Issue

Faced with this challenge, the first edition of this Special Issue offers compelling examples of how the accuracy of resource assessment and management for fisheries can be improved through the generation of new knowledge and detailed information on biological, environmental, biophysical, and behavioral aspects—in some cases, focusing on resources with a recognized degree of threat on the IUCN Red List—as well as the implementation of classical models of fisheries biology and population dynamics and regional ocean circulation models to predict the effect of climate change, and the development of new and sophisticated methodological approaches to fishery resources developed for diverse environments, such as river [38,39,40], coastal [41,42], estuarine [43,44], and marine [45,46,47] ecosystems.

Thus, research developed using poor data modeling and/or novel methodological approaches is presented, such as the multi-gear mean standardization method and Bayesian state-space surplus production model [45], as well as length-based approaches [41], which improved the accuracy of assessments of the stock of hairtail Trichiurus lepturus in Korean waters [45] and tiger tooth croaker Otolithes ruber in Makran, Pakistan [41], respectively, and can establish the status of fisheries as well as providing recommendations to mitigate overfishing and for the sustainable use of resources. A review of stock assessment models, with an emphasis on the Gordon–Schaefer surplus production model, allowed for an analysis of the strengths and limitations of existing models and highlighted the usefulness of this model for assessing fish stocks in developing countries such as Malawi. Recommendations are also presented for integrating reference points, bifurcation analyses, depletion calculations, and sustainable annual production [42] into the assessment of fishery resources.

Regarding endangered species, such as the elasmobranchs caught in shrimp trawling in the Gulf of Mexico [46] and the European Anguilla anguilla [44], ontogenetic and bathymetric segregation patterns are presented to formulate bycatch reduction strategies [46]. Through the application of Chemical Integration Approaches, eel traceability is used to differentiate geographical origin, providing a tool for the prevention of illegal fishing [44], which could significantly improve species-specific conservation efforts.

Studies with a more ecological focus present a modification to the ESHIPPO model (ecological specialization and habitat alteration, invasive species, pollution, human population growth, and overexploitation) by incorporating the genetic structure of brown trout, highlighting the consequences of fishery management that continues to rely heavily on restocking programs and the urgent need for the differentiated management of each brown trout population in the Central Balkans, Serbia [40]. A mark–recapture study recognized the importance of considering the sedentary and mobile displacement strategy for the Salmo trutta complex residing in Mediterranean streams, based on environmental factors and intrinsic characteristics such as sex and body size, in conservation plans to preserve the functional and genetic connectivity of the population [39]. Another study on the production of Salmo trutta complex, also in Mediterranean streams, determined that variability in water discharge and habitat complexity modulate interannual productivity [38].

An analysis involving recent data and data from eight years ago on the biology and population dynamics of the Tasmanian perch Percalates colonorum in Australia established that this is a reproductively active and stable population. However, the identification of its restricted distribution, variable recruitment, slow growth, and small population size suggests a need for greater conservation efforts [43].

Finally, a biophysical assessment evaluated the effect of climate change on the spawning grounds of chub mackerel Scomber japonicus, generating a spawning ground index based on a Regional Ocean Circulation Model for the Northwestern Pacific, which warns that, by 2050, spawning grounds will shift northward due to ocean surface warming, causing breeding grounds to shift westward from the Sea of Japan/East Sea to the Korea Strait and Yellow Sea, with a consequent impact on recruitment and the spatial–temporal distribution of fisheries [47].

3. Future Research

Notably, the specific contributions of the research presented in this Special Issue help to fill gaps in the knowledge, providing support for the management of fishery resources, as well as guidance for future studies that wish to replicate the methodological approaches outlined here.

Clearly, there are still many issues that need to be addressed to improve the knowledge of fisheries’ biology and the population dynamics of fishery resources. A major effort must be made to increase biophysical studies that show the influence of environmental factors on resource dynamics and studies on adaptation and resilience to the imminent climate change that is affecting the sustainable use of the world’s natural resources, including marine and freshwater fisheries, which are a vital source of food and livelihood.

The integrated approach used by Leitão and Cánovas [48], which evaluates the impact of climate change from the species to the economic levels and incorporates sensitivity (ecological traits) to weight habitat suitability, provides a significant asset to assessments of climate change’s impact on fisheries. According to these authors, maintaining sustainable fishing management strategies is the best way to mitigate the effects of climate change; however, the absence of sustained partnerships, imbalances in research collaboration, restricted data accessibility and reliability, the limited representation of perspectives from the Global South and an inadequate understanding of fisheries’ carbon emissions constitute the key research gaps identified by Xu et al. [28] that need to be addressed.

Additionally, the need for international cooperation, regular management reviews, and effective monitoring are identified by Koerner et al. [26] as indispensable to adequate preparation for the impacts of climate change on marine resources. The development of models for the impacts of multiple drivers on marine resources is relatively new [27]. Thus, the development of multi-stressor models requires collaboration between physiologists, biologists, oceanographers, and modelers, and a clear understanding of fisheries’ biology and the population dynamics of fishery resources.

Understanding the physiological, morphological, and behavioral responses of fish to the environmental and anthropogenic threats to which they are exposed is essential to their conservation and management. An impact evaluation of the biomass remotion of target species and the resulting disruption to food webs is essential to understand biodiversity losses and their effect on ecosystem structure and function. Assessments of population genetics, diversity, and genetic structure are also essential when taking measures to ensure the sustainability of exploited resources.

In addition, an economic and social assessment of the value chain from production to the final consumer, including the processing and marketing of fishery products, would provide a better understanding of the dynamics and complexity involved in fishing activities and how fish stocks respond to these fluctuations, as well as identifying appropriate market-based solutions to ensure fishermen’s livelihoods. The private sector and industries can provide financial support and innovations to improve the overall efficiency and effectiveness of fishing [49]. Training to improve business skills in fishermen, especially those involved in small-scale fishing, would improve the marketing and profitability of fish products, and thereby increase economic income. Improving the integration of fisheries into food systems requires the active participation of all stakeholders to ensure that historically marginalized groups are heard and empowered [49].

Innovation, as an essential component in strengthening socio-economic systems by integrating the sustainable use of hydrobiological resources, along with the development of science and technology for the benefit of coastal communities [36], is also an issue that needs to be addressed. Additionally, research that promotes rural innovation in fisheries’ resources as a mechanism to help strengthen small-scale fishing communities should be developed. Information gaps also exist regarding quality and safety, value-added, and economic diversification, as well as the traceability of fishery products.

Community-based data-collection programs in which fishers are trained to collect and analyze their own fishery and socio-economic data enhance social cohesion and incentivize fishers’ involvement in co-management, in addition to improving their empirical knowledge. For data-poor fisheries, these approaches may constitute the only viable option for systematic data collection [7]. Therefore, their implementation could be of great help in advancing the generation of new knowledge.

Hunger and malnutrition occur unevenly according to continent and country, as well as within them, and current agri-food systems are highly vulnerable to disruptions and alterations resulting from climate variability and extreme weather events, which exacerbate growing inequalities [2]. Given these facts, the generation of specific scientific knowledge for each fishery resource, focusing on the topics highlighted here as priorities, will help fill information gaps, enabling the management of unequal fishery resources by country to have the strongest possible scientific basis so that fisheries can continue to fulfill their role in providing food security, employment, and economic support through industrial and small-scale fishing.

4. Conclusions

This book provides scientific knowledge that not only fills information gaps but also contributes to the conservation and management of at least 10 fishery resources exploited in rivers, coastal areas, marine areas, and estuaries in Korea, Pakistan, Malawi, the Gulf of Mexico, Europe, Serbia, Mediterranean currents, Australia, and the Northwest Pacific, based on classical and cutting-edge methodological approaches.

There are still many fishery resources that require evaluation from different perspectives to address the challenges facing fisheries at the local, national, regional, and global levels, given the lack of a scientific assessment of the pressures, ecosystems effects, economic efficiency or governance. Therefore, progress must be made to generate specific information for each fishery resource in every country.

Biological, ecological, social, cultural, economic and legal information is indispensable to decision-making that ensures sustainable fisheries and ecosystems.

As scientific knowledge of fisheries’ biology, the population dynamics of fishery resources, and the dynamics of fishing communities advances, more information will be available for efficient management to address climate change and address problems related to overfishing, deficient socio-ecological and socio-economic systems and challenges to food security. Future research should be conducted with this perspective in mind.