Inland recreational fisheries contribute nutritional benefits and economic value but are vulnerable to climate change.

Inland recreational fishing is primarily considered a leisure-driven activity in freshwaters, yet its harvest can contribute to food systems. Here we estimate that the harvest from inland recreational fishing equates to just over one-tenth of all reported inland fisheries catch globally. The estimated total consumptive use value of inland recreational fish destined for human consumption may reach US$9.95 billion annually. We identify Austria, Canada, Germany and Slovakia as countries above the third quantile for nutrition, economic value and climate vulnerability. These results have important implications for populations dependent on inland recreational fishing for food. Our findings can inform climate adaptation planning for inland recreational fisheries, particularly those not currently managed as food fisheries.

Global dataset of species-specific inland recreational fisheries harvest for consumption.

Inland recreational fisheries, found in lakes, rivers, and other landlocked waters, are important to livelihoods, nutrition, leisure, and other societal ecosystem services worldwide. Although recreationally-caught fish are frequently harvested and consumed by fishers, their contribution to food and nutrition has not been adequately quantified due to lack of data, poor monitoring, and under-reporting, especially in developing countries. Beyond limited global harvest estimates, few have explored species-specific harvest patterns, although this variability has implications for fisheries management and food security. Given the continued growth of the recreational fishery sector, understanding inland recreational fish harvest and consumption rates represents a critical knowledge gap. Based on a comprehensive literature search and expert knowledge review, we quantified multiple aspects of global inland recreational fisheries for 81 countries spanning ~192 species. For each country, we assembled recreational fishing participation rate and estimated species-specific harvest and consumption rate. This dataset provides a foundation for future assessments, including understanding nutritional and economic contributions of inland recreational fisheries.

A global dataset of inland fisheries expert knowledge.

Inland fisheries and their freshwater habitats face intensifying effects from multiple natural and anthropogenic pressures. Fish harvest and biodiversity data remain largely disparate and severely deficient in many areas, which makes assessing and managing inland fisheries difficult. Expert knowledge is increasingly used to improve and inform biological or vulnerability assessments, especially in data-poor areas. Integrating expert knowledge on the distribution, intensity, and relative influence of human activities can guide natural resource management strategies and institutional resource allocation and prioritization. This paper introduces a dataset summarizing the expert-perceived state of inland fisheries at the basin (fishery) level. An electronic survey distributed to professional networks (June-September 2020) captured expert perceptions (n = 536) of threats, successes, and adaptive capacity to fisheries across 93 hydrological basins, 79 countries, and all major freshwater habitat types. This dataset can be used to address research questions with conservation relevance, including: demographic influences on perceptions of threat, adaptive capacities for climate change, external factors driving multi-stressor interactions, and geospatial threat assessments.

Effects of climate and land-use changes on fish catches across lakes at a global scale.

Globally, our knowledge on lake fisheries is still limited despite their importance to food security and livelihoods. Here we show that fish catches can respond either positively or negatively to climate and land-use changes, by analyzing time-series data (1970-2014) for 31 lakes across five continents. We find that effects of a climate or land-use driver (e.g., air temperature) on lake environment could be relatively consistent in directions, but consequential changes in a lake-environmental factor (e.g., water temperature) could result in either increases or decreases in fish catch in a given lake. A subsequent correlation analysis indicates that reductions in fish catch was less likely to occur in response to potential climate and land-use changes if a lake is located in a region with greater access to clean water. This finding suggests that adequate investments for water-quality protection and water-use efficiency can provide additional benefits to lake fisheries and food security.

To manage inland fisheries is to manage at the social-ecological watershed scale.

Approaches to managing inland fisheries vary between systems and regions but are often based on large-scale marine fisheries principles and thus limited and outdated. Rarely do they adopt holistic approaches that consider the complex interplay among humans, fish, and the environment. We argue that there is an urgent need for a shift in inland fisheries management towards holistic and transdisciplinary approaches that embrace the principles of social-ecological systems at the watershed scale. The interconnectedness of inland fisheries with their associated watershed (biotic, abiotic, and humans) make them extremely complex and challenging to manage and protect. For this reason, the watershed is a logical management unit. To assist management at this scale, we propose a framework that integrates disparate concepts and management paradigms to facilitate inland fisheries management and sustainability. We contend that inland fisheries need to be managed as social-ecological watershed system (SEWS). The framework supports watershed-scale and transboundary governance to manage inland fisheries, and transdisciplinary projects and teams to ensure relevant and applicable monitoring and research. We discuss concepts of social-ecological feedback and interactions of multiple stressors and factors within/between the social-ecological systems. Moreover, we emphasize that management, monitoring, and research on inland fisheries at the watershed scale are needed to ensure long-term sustainable and resilient fisheries.

On the sustainability of inland fisheries: Finding a future for the forgotten.

At present, inland fisheries are not often a national or regional governance priority and as a result, inland capture fisheries are undervalued and largely overlooked. As such they are threatened in both developing and developed countries. Indeed, due to lack of reliable data, inland fisheries have never been part of any high profile global fisheries assessment and are notably absent from the Sustainable Development Goals. The general public and policy makers are largely ignorant of the plight of freshwater ecosystems and the fish they support, as well as the ecosystem services generated by inland fisheries. This ignorance is particularly salient given that the current emphasis on the food-water-energy nexus often fails to include the important role that inland fish and fisheries play in food security and supporting livelihoods in low-income food deficit countries. Developing countries in Africa and Asia produce about 11 million tonnes of inland fish annually, 90 % of the global total. The role of inland fisheries goes beyond just kilocalories; fish provide important micronutrients and essentially fatty acids. In some regions, inland recreational fisheries are important, generating much wealth and supporting livelihoods. The following three key recommendations are necessary for action if inland fisheries are to become a part of the food-water-energy discussion: invest in improved valuation and assessment methods, build better methods to effectively govern inland fisheries (requires capacity building and incentives), and develop approaches to managing waters across sectors and scales. Moreover, if inland fisheries are recognized as important to food security, livelihoods, and human well-being, they can be more easily incorporated in regional, national, and global policies and agreements on water issues. Through these approaches, inland fisheries can be better evaluated and be more fully recognized in broader water resource and aquatic ecosystem planning and decision-making frameworks, enhancing their value and sustainability for the future.

Failure to engage the public in issues related to inland fishes and fisheries: strategies for building public and political will to promote meaningful conservation.

Generating awareness of environmental conservation issues among the public is essential if there is an expectation of them to alter their behaviour, facilitate informed decisions and engage governments or regulatory authorities to take action. There are, however, exceedingly few public engagement success stories related to inland fishes and fisheries policy and resource allocation decisions. Inland aquatic resources and their associated fisheries provide employment, recreation, culture and, in developing regions, a considerable proportion of human nutrition and food security. Freshwater fishes are incredibly diverse but are among the most endangered organisms globally. Many threats to inland fisheries are driven largely by externalities to inland fisheries. The purpose of this paper is to draw attention to the role and plight of inland fishes and fisheries, and the need to generate the public and political will necessary to promote meaningful conservation. With this paper, the extent to which the scientific and environmental management communities have failed to engage the public in issues related to inland fishes and fisheries is characterized. Next, the barriers or factors that serve as the basis for the problem with public engagement are identified. The paper concludes by identifying strategies, including those focused on environmental education initiatives, for building the public and political will necessary to promote meaningful conservation of inland fishes and fisheries in developed and developing countries. Scientists, environmental managers, non-governmental organizations, politicians, regulatory authorities and the media all have important roles to play in overcoming challenges to inland fisheries. Failure to engage the public in freshwater conservation and management issues will impede efforts to stem the loss of freshwater habitats, fisheries and aquatic biodiversity. Thankfully, there are opportunities to learn from success stories related to other environmental issues and initiatives that have been successful in marine fish conservation.

Ecosystem approach to inland fisheries: research needs and implementation strategies.

Inland fisheries are a vital component in the livelihoods and food security of people throughout the world, as well as contributing huge recreational and economic benefits. These valuable assets are jeopardized by lack of research-based understanding of the impacts of fisheries on inland ecosystems, and similarly the impact of human activities associated with inland waters on fisheries and aquatic biodiversity. To explore this topic, an international workshop was organized in order to examine strategies to incorporate fisheries into ecosystem approaches for management of inland waters. To achieve this goal, a new research agenda is needed that focuses on: quantifying the ecosystem services provided by fresh waters; quantifying the economic, social and nutritional benefits of inland fisheries; improving assessments designed to evaluate fisheries exploitation potential; and examining feedbacks between fisheries, ecosystem productivity and aquatic biodiversity. Accomplishing these objectives will require merging natural and social science approaches to address coupled social-ecological system dynamics.

On the (mis)use of cross-price effects to gauge the effectiveness of smokeless tobacco in smoking cessation. A comment on Bask and Melkersson.

In a recent edition of this journal Mikael Bask and Maria Melkersson suggested that moist snuff, snus to the Swedes, is not an effective tool in cigarette smoking cessation. The sole basis for this conclusion is their empirical findings concerning the cross-price elasticity of demand between cigarettes and snus. Specifically, they find that, "The cross-price elasticities are negative, which indicates that snus contributes to increased smoking. Thus, even if snus taking is less harmful than cigarette smoking, it is not advisable to encourage its use in smoking cessation programs." We find this conclusion to be unwarranted. It is based on a model estimated with inappropriate data; it is based on a misspecified model with questionable theoretical underpinnings; and no evidence is presented as to the statistical significance of the cross-price effects. Furthermore, even if we ignore these technical criticisms, their conclusions are unfounded because they are based on an inappropriate conceptual experiment. We first address some technical problems with the Bask and Melkersson analysis, and then we address the fundamental flaw in their reasoning.

Calcium diglutamate improves taste characteristics of lower-salt soup.

OBJECTIVE: : To ascertain (1) whether the taste characteristics of a conventionally-salted (150 mM NaCl) soup can be reproduced in soups of substantially lower NaCl level with the help of added glutamate, and (2) whether calcium diglutamate (CDG) is equivalent to monosodium glutamate (MSG) in its effect on the taste of soup. DESIGN: : Cross-sectional, with multiple measurements on each subject. SETTING: : Healthy university students. SUBJECTS: : A total of 107 volunteers, recruited by on-campus advertising. METHODS: : Subjects tasted 32 soups, with all possible combinations of four NaCl concentrations (0-150 mM), four glutamate levels (0-43 mM), and two glutamate types (MSG, CDG). MAIN OUTCOME MEASURES: : Ratings of each soup on six scales (liking, flavour-intensity, familiarity, naturalness of taste, richness of taste, saltiness). RESULTS: : A 50 or 85 mM NaCl soup with added CDG or MSG is rated as high as, or higher than, a 150 mM NaCl soup free of added glutamate on five of the six scales (the exception being saltiness). CDG and MSG have equivalent effects. CONCLUSIONS: : Addition of glutamate allows substantial reductions in Na content of soup, without significant deterioration of taste. CDG and MSG have equivalent effects, but use of CDG permits a greater reduction in Na intake.

Enantioselective biotransformations using rhodococci.

The use of enzymes and whole cells in enantioselective biotransformation reactions is briefly reviewed. A Rhodococcus strain is shown to possess nitrile hydratase and amidase activity. The organism can be used for the enantioselective biotransformation of racemic alpha-amino amides to (S) alpha-amino acids with an enantiomeric excess (ee) of > 98%. Enantioselectivity is effectively time independent allowing easy quantitative conversion of racemic mixtures into enantiomerically pure alpha-amino amides and alpha-amino acids. The reaction is effective for a wide range of alpha-substituents. The pH-dependence of the reaction indicates that the alpha-amino amide is bound to the amidase enzyme in its neutral unprotonated form.

A population-based study of the relationship between salt intake, bone resorption and bone mass.

OBJECTIVE: To explore the relationship between urinary sodium (the best measure of salt intake), urinary calcium, urinary deoxypyridinoline (DPYR) and bone mass. DESIGN: Cross-sectional study. SETTING: Population based sample of healthy Hobart residents. SUBJECTS: One hundred and fifty-four (M = 34, F = 120) subjects invited to take part from a systematic sample of the electoral roll and a single newspaper advertisement. RESULTS: In both sexes, urinary sodium correlated moderately with urinary DPYR (r = 0.32, P < 0.0001) and urinary calcium (r = 0.37, P < 0.0001). In multivariate analysis, the combination of urinary sodium, total body bone area, age and sex explained 22% of the variation in log-transformed DPYR (P < 0.00001). In univariate analysis, both urinary sodium and urinary DPYR were strongly associated with bone mineral content and bone mineral density at all sites but this association disappeared after adjustment for confounders particularly body weight. CONCLUSIONS: This study has shown that salt intake is associated with markers of bone resorption in a population-based sample of males and females and appears likely to be a risk factor for osteoporosis despite the lack of a demonstrable association between bone mass and a single measure of urinary sodium excretion. Further studies are needed to define the effect of salt intake on bone mass and fractures more clearly. These studies will need to be either longitudinal or interventional in design with repeated measures of urinary sodium so that habitual sodium intake can be accurately assessed and regression dilution bias can be minimised.