USGS ScienceSearch

Geology topics

Abigail J. Lynch

Publications and source records attributed to Abigail J. Lynch.

At least 55 records · Page 3Linked to original sources

Stocking fish in inland waters: Opportunities and risks for sustainable food systems

Stocking is one of the foremost tools in the inland fisheries management toolbox, but it comes with both opportunities and risks. Stocking is often used as compensation for depleted wild populations, particularly where recruitment processes have been disrupted, but it can introduce disease, disrupt community structures, reduce genetic integrity, and cause conflicts between fishery stakeholders. Despite its widespread use, examples of effective stocking for food fisheries in inland waters are sparse in the peer-reviewed literature. Nevertheless, it is well established that stocking is frequently used to maintain fish yield, so there is a need to conduct the practice in a robust manner that minimises the potential risks. This paper serves as the front matter for a special section of Fisheries Management and Ecology focused on fresh waters feeding the world, which resulted from two panel sessions, one focused on aquaculture and one focused on stocking, hosted by the international InFish research network ( https://infish.org/ ). The paper highlights current practices of fish stock enhancement in inland waters for food, examines potential synergies and interactions of stock enhancement programmes with aquaculture, and provides an outline framework for responsible management of fish stock enhancement.

Fisheries Management and Ecology

Future-proofing the Emergency Recovery Plan for freshwater biodiversity

Freshwater biodiversity loss is accelerating globally, but humanity can change this trajectory through actions that enable recovery. To be successful, these actions require coordination and planning at a global scale. The Emergency Recovery Plan for global freshwater biodiversity aims to reduce the risk for freshwater biodiversity loss through six priority actions: (1) accelerate implementation of environmental flows; (2) improve water quality to sustain aquatic life; (3) protect and restore critical habitats; (4) manage exploitation of freshwater species and riverine aggregates; (5) prevent and control nonnative species invasions in freshwater habitats; and (6) safeguard and restore freshwater connectivity. These actions can be implemented using future-proofing approaches that anticipate future risks (e.g., emerging pollutants, new invaders, and synergistic effects) and minimize likely stressors to make conservation of freshwater biodiversity more resilient to climate change and other global environmental challenges. While uncertainty with respect to past observations is not a new concern for freshwater biodiversity, future-proofing has the distinction of accounting for the uncertainty of future conditions that have no historical baseline. The level of uncertainty with respect to future conditions is unprecedented. Future-proofing of the Emergency Recovery Plan for freshwater biodiversity will require anticipating future changes and developing and implementing actions to address those future changes. Here, we showcase future-proofing approaches likely to be successful using local case studies and examples. Ensuring that response options within the Emergency Recovery Plan are future-proofed will provide decision makers with science-informed choices, even in the face of uncertain and potentially new future conditions. We are at an inflection point for global freshwater biodiversity loss; learning from defeats and successes can support improved actions toward a sustainable future.

Environmental Reviews

Estimating lentic recreational fisheries catch and effort across the United States

Recreational fisheries represent a socially, ecologically, and economically significant component of global fisheries. The U.S. Inland Creel and Angler Survey Catalog (CreelCat) database includes inland recreational fisheries survey data across the United States to facilitate large-scale analyses. However, because survey methods differ, a statistical method capable of integrating these surveys is necessary to assess patterns and relationships across regions. Here, we developed a hierarchical generalized linear mixed modeling approach to estimate the relationship between daily recreational fisheries catch and effort based on waterbody, socio-economic, and ecological covariates. We applied this approach to CreelCat data on lentic waterbodies and found that recreational fisheries catch and effort were non-linearly related (i.e., catch per unit of effort declined as effort increased), where effort varied regionally and by waterbody area, median county age, and distance to nearest primary road. This modeling approach could be used to inform data-poor regions or waterbodies, make comparisons across spatial scales, and, with the inclusion of socio-economic and ecological factors, inform management techniques in an era of shifting demographics and landscapes.

Fisheries Management and Ecology

A brave new world: Managing for biodiversity conservation under ecosystem transformation

Traditional conservation practices have primarily relied on maintaining biodiversity by preserving species and habitats in place. Many regions are experiencing unprecedented environmental conditions, shifts in species distribution and habitats, and high turnover in species composition, resulting in ecological transformation. Natural resource managers have lacked tools for identifying and selecting strategies to manage ecosystem transformation. A recently formalized decision support framework provides a way for managers to resist, accept, or direct (RAD) the trajectory of change. We begin by identifying how historical conservation practices are built into the RAD framework. Next, we describe how RAD can be used to implement climate change adaptation actions, using examples from the Mojave Desert to provide ecological context. Third, we discuss how the RAD framework can assist with the creation of conservation portfolios, facilitating the maintenance of overall biodiversity across a landscape. Preserving species assemblages in their current state, or restoring them to historical conditions, will not always be possible, and RAD allows for explicit deliberation about when and where to prioritize scarce resources. We conclude with a set of guidelines for conservation practitioners or managers moving forward. Although operating under an increasingly uncertain future is daunting, managers can utilize RAD to conserve biodiversity and effectively handle ecosystem transformation.

Land

Global responses to the COVID-19 pandemic by recreational anglers: Considerations for developing more resilient and sustainable fisheries

The global COVID-19 pandemic resulted in many jurisdictions implementing orders restricting the movements of people to inhibit virus transmission, with recreational angling often either not permitted or access to fisheries and/or related infrastructure being prevented. Following the lifting of restrictions, initial angler surveys and licence sales suggested increased participation and effort, and altered angler demographics, but with evidence remaining limited. Here, we overcome this evidence gap by identifying temporal changes in angling interest, licence sales, and angling effort in world regions by comparing data in the ‘pre-pandemic’ (up to and including 2019); ‘acute pandemic’ (2020) and ‘COVID-acclimated’ (2021) periods. We then identified how changes can inform the development of more resilient and sustainable recreational fisheries. Interest in angling (measured here as angling-related internet search term volumes) increased substantially in all regions during 2020. Patterns in licence sales revealed marked increases in some countries during 2020 but not in others. Where licence sales increased, this was rarely sustained in 2021; where there were declines, these related to fewer tourist anglers due to movement restrictions. Data from most countries indicated a younger demographic of people who participated in angling in 2020, including in urban areas, but this was not sustained in 2021. These short-lived changes in recreational angling indicate efforts to retain younger anglers could increase overall participation levels, where efforts can target education in appropriate angling practices and create more urban angling opportunities. These efforts would then provide recreational fisheries with greater resilience to cope with future global crises, including facilitating the ability of people to access angling opportunities during periods of high societal stress.

Reviews in Fish Biology and Fisheries

Climate change and the global redistribution of biodiversity: Substantial variation in empirical support for expected range shifts

Background Among the most widely predicted climate change-related impacts to biodiversity are geographic range shifts, whereby species shift their spatial distribution to track their climate niches. A series of commonly articulated hypotheses have emerged in the scientific literature suggesting species are expected to shift their distributions to higher latitudes, greater elevations, and deeper depths in response to rising temperatures associated with climate change. Yet, many species are not demonstrating range shifts consistent with these expectations. Here, we evaluate the impact of anthropogenic climate change (specifically, changes in temperature and precipitation) on species’ ranges, and assess whether expected range shifts are supported by the body of empirical evidence. Methods We conducted a Systematic Review, searching online databases and search engines in English. Studies were screened in a two-stage process (title/abstract review, followed by full-text review) to evaluate whether they met a list of eligibility criteria. Data coding, extraction, and study validity assessment was completed by a team of trained reviewers and each entry was validated by at least one secondary reviewer. We used logistic regression models to assess whether the direction of shift supported common range-shift expectations (i.e., shifts to higher latitudes and elevations, and deeper depths). We also estimated the magnitude of shifts for the subset of available range-shift data expressed in distance per time (i.e., km/decade). We accounted for methodological attributes at the study level as potential sources of variation. This allowed us to answer two questions: (1) are most species shifting in the direction we expect (i.e., each observation is assessed as support/fail to support our expectation); and (2) what is the average speed of range shifts? Review findings We found that less than half of all range-shift observations (46.60%) documented shifts towards higher latitudes, higher elevations, and greater marine depths, demonstrating significant variation in the empirical evidence for general range shift expectations. For the subset of studies looking at range shift rates, we found that species demonstrated significant average shifts towards higher latitudes (average = 11.8 km/dec) and higher elevations (average = 9 m/dec), although we failed to find significant evidence for shifts to greater marine depths. We found that methodological factors in individual range-shift studies had a significant impact on the reported direction and magnitude of shifts. Finally, we identified important variation across dimensions of range shifts (e.g., greater support for latitude and elevation shifts than depth), parameters (e.g., leading edge shifts faster than trailing edge for latitude), and taxonomic groups (e.g., faster latitudinal shifts for insects than plants). Conclusions Despite growing evidence that species are shifting their ranges in response to climate change, substantial variation exists in the extent to which definitively empirical observations confirm these expectations. Even though on average, rates of shift show significant movement to higher elevations and latitudes for many taxa, most species are not shifting in expected directions. Variation across dimensions and parameters of range shifts, as well as differences across taxonomic groups and variation driven by methodological factors, should be considered when assessing overall confidence in range-shift hypotheses. In order for managers to effectively plan for species redistribution, we need to better account for and predict which species will shift and by how much. The dataset produced for this analysis can be used for future research to explore additional hypotheses to better understand species range shifts.

Journal of Environmental Evidence

Towards vibrant fish populations and sustainable fisheries that benefit all: Learning from the last 30 years to inform the next 30 years

A common goal among fisheries science professionals, stakeholders, and rights holders is to ensure the persistence and resilience of vibrant fish populations and sustainable, equitable fisheries in diverse aquatic ecosystems, from small headwater streams to offshore pelagic waters. Achieving this goal requires a complex intersection of science and management, and a recognition of the interconnections among people, place, and fish that govern these tightly coupled socioecological and sociotechnical systems. The World Fisheries Congress (WFC) convenes every four years and provides a unique global forum to debate and discuss threats, issues, and opportunities facing fish populations and fisheries. The 2021 WFC meeting, hosted remotely in Adelaide, Australia, marked the 30th year since the first meeting was held in Athens, Greece, and provided an opportunity to reflect on progress made in the past 30 years and provide guidance for the future. We assembled a diverse team of individuals involved with the Adelaide WFC and reflected on the major challenges that faced fish and fisheries over the past 30 years, discussed progress toward overcoming those challenges, and then used themes that emerged during the Congress to identify issues and opportunities to improve sustainability in the world's fisheries for the next 30 years. Key future needs and opportunities identified include: rethinking fisheries management systems and modelling approaches, modernizing and integrating assessment and information systems, being responsive and flexible in addressing persistent and emerging threats to fish and fisheries, mainstreaming the human dimension of fisheries, rethinking governance, policy and compliance, and achieving equity and inclusion in fisheries. We also identified a number of cross-cutting themes including better understanding the role of fish as nutrition in a hungry world, adapting to climate change, embracing transdisciplinarity, respecting Indigenous knowledge systems, thinking ahead with foresight science, and working together across scales. By reflecting on the past and thinking about the future, we aim to provide guidance for achieving our mutual goal of sustaining vibrant fish populations and sustainable fisheries that benefit all. We hope that this prospective thinking can serve as a guide to (i) assess progress towards achieving this lofty goal and (ii) refine our path with input from new and emerging voices and approaches in fisheries science, management, and stewardship.

Reviews in Fish Biology and Fisheries

The RACE for freshwater biodiversity: Essential actions to create the social context for meaningful conservation

Freshwater habitats are experiencing two to three times the rate of biodiversity loss of terrestrial and marine habitats. As status quo actions within the conservation community are not reversing the downward trajectory for freshwater biodiversity, we propose four actions to shift the narrative such that freshwater biodiversity is no longer invisible and overlooked, but rather explicitly recognized, valued, and protected: (1) Reshape our relationship with freshwater habitats and biodiversity, (2) Appreciate indigenous knowledge systems relating to freshwater habitats, (3) Connect science more directly to action, and (4) Elevate freshwater habitats as a unique “domain” that requires explicit recognition in conservation planning (RACE). We highlight roles that both freshwater scientists and the wider conservation community can play in implementing the four actions such that the “RACE” can be won.

Conservation Science and Practice

People need freshwater biodiversity

Freshwater biodiversity, from fish to frogs and microbes to macrophytes, provides a vast array of services to people. Mounting concerns focus on the accelerating pace of biodiversity loss and declining ecological function within freshwater ecosystems that continue to threaten these natural benefits. Here, we catalog nine fundamental ecosystem services that the biotic components of indigenous freshwater biodiversity provide to people, organized into three categories: material (food; health and genetic resources; material goods), non-material (culture; education and science; recreation), and regulating (catchment integrity; climate regulation; water purification and nutrient cycling). If freshwater biodiversity is protected, conserved, and restored in an integrated manner, as well as more broadly appreciated by humanity, it will continue to contribute to human well-being and our sustainable future via this wide range of services and associated nature-based solutions to our sustainable future.

WIREs Water

Density effects on native and non-native trout survival in streams

Environmental stressors associated with a changing climate and non-native fish, individually, represent significant threats to native fish conservation. These threats can exacerbate risks to native fishes when conditions interact at the trailing edge of a population's distribution. We collected capture–mark–recapture data for Rio Grande cutthroat trout (RGCT, Oncorhynchus clarkii virginalis ) at the trailing edge of all cutthroat trout distributions from eight northern New Mexico populations. We used a factorial sampling design from streams characterised as “cool” or “warm” and whether RGCT were sympatric with non-native brown trout ( Salmo trutta ). We tested competing hypotheses that warm temperatures, reduced flows, high densities and sympatry with brown trout would negatively impact RGCT apparent survival rates. We found the strongest evidence for a non-native trout interaction with total trout density affecting RGCT apparent survival rates. Our results are consistent with patterns observed in northern cutthroat trout populations where non-native salmonids negatively impacted apparent survival rates. We also found that a negative density effect was observed on allopatric RGCT and sympatric brown trout apparent survival, but a positive density effect was observed for sympatric RGCT. These results suggest higher density populations of RGCT may be more resilient to displacement by non-native trout than low-density populations.

Ecology of Freshwater Fish

Preventing and controlling nonnative species invasions to bend the curve of global freshwater biodiversity loss

The Emergency Recovery Plan for freshwater biodiversity recognizes that addressing nonnative species is one of six principal actions needed to bend the curve in freshwater biodiversity loss. This is because introduction rates of nonnative species continue to accelerate globally and where these species develop invasive populations, they can have severe impacts on freshwater biodiversity. The most effective management measure to protect freshwater biodiversity is to prevent introductions of nonnative species. Should a nonnative species be introduced, however, then its early detection and the implementation of rapid reaction measures can avoid it establishing and dispersing. If these measures are unsuccessful and the species becomes invasive, then control and containment measures can minimize its further spread and impact. Minimizing further spread and impact includes control methods to reduce invader abundance and containment methods such as screening of invaded sites and strict biosecurity to avoid the invader dispersing to neighbouring basins. These management actions have benefitted from developments in invasion risk assessment that can prioritize species according to their invasion risk and, for species already invasive, ensure that management actions are commensurate with assessed risk. The successful management of freshwater nonnative species still requires the overcoming of some implementation challenges, including nonnative species often being a symptom of degraded habitats rather than the main driver of ecological change, and eradication methods often being nonspecies specific. Given the multiple anthropogenic stressors in freshwaters, nonnative species management must work with other restoration strategies if it is to deliver the Emergency Recovery Plan for freshwater biodiversity.

Environmental Reviews

People need freshwater biodiversity: Nine reasons freshwater biodiversity is important for humans

Freshwater biodiversity, from fish to frogs and microbes to macrophytes, provides a vast array of services to people. These services are under a growing threat as human-related pressure threatens freshwater biodiversity on multiple fronts. Here, Abigail Lynch and colleagues discuss nine fundamental ecosystem services that freshwater biodiversity provide to people. Given the importance of freshwater biodiversity to our very existence, they make a plea for a redoubled effort to better conserve this precious resource.

Global Water Forum

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.

Scientific Data

Overturning stereotypes: The fuzzy boundary between recreational and subsistence inland fisheries

Inland recreational fisheries provide numerous socio- economic benefits to fishers, families and communities. Recreationally harvested fish are also frequently consumed and may provide affordable and sustainable but undervalued contributions to human nutrition. Quantifying the degree to which recreationally harvested fish contribute to food security and subsistence is impeded by lack of data on harvest and consumption and by the difficulty in differentiating among recreational and subsistence fisheries. Recreational harvest records tend to be limited to wealthy, food- secure countries and well- monitored fisheries with clear regulations or permitting systems. These records often neglect components of recreational harvest among food- insecure fishers who are potentially more likely to have consumption as a motivation. Here, we highlight the ‘fuzzy boundary’ that can exist between inland recreational and subsistence fisheries and argue that unreported consumption is likely to be a hidden contributor to food security in some populations. We draw on local case studies from around the world to highlight specific instances where recreationally harvested fish species contribute food and subsistence benefits to participating communities. We use these examples to highlight the diversity of ways that inland recreational fisheries contribute to human nutrition, knowledge gaps in understanding recreational fishing for food, and consequences of not accounting for them as food fisheries in policy and management. The aim of this paper is to draw the attention of resource managers and policy makers, create greater social awareness of the importance of recreational fisheries and bring to light this hidden contribution of inland fisheries to nutrition and subsistence.

Northern Territory, Virginia

Reducing uncertainty in climate change responses of inland fishes: A decision-path approach

Climate change will continue to be an important consideration for conservation practitioners. However, uncertainty in identifying appropriate management strategies, particularly for understudied species and regions, constrains the implementation of science-based solutions and adaptation strategies. Here, we share a decision-path approach to reduce uncertainty in climate change responses of inland fishes to inform conservation and adaptation planning. With the Fish and Climate Change database (FiCli), a comprehensive, online, public database of peer-reviewed literature on documented and projected climate impacts to inland fishes, users can identify relevant studies and associated management recommendations via geographic regions, response types (i.e., fish assemblage dynamics, demographic, distributional, evolutionary, phenological), fish taxa, and traits (e.g., thermal guilds, feeding type, parental care, habitat type) and use a suite of summary tools to make more informed decisions. For both data-rich and data-poor scenarios, we demonstrate that this approach can reduce uncertainty in understanding climate change responses. Using thermal sensitivity as an example, we also establish the utility of FiCli database to address other user-defined, management-relevant questions via supplementary analyses. This decision-path approach can be applied to rapid assessments, management decisions, and policy development and may serve as a model for other conservation decision-making processes.

Conservation Science and Practice

A future for the inland fish and fisheries hidden within the sustainable development goals

The United Nations Sustainable Development Goals (SDGs) are a unifying call for change - guiding global actions at multiple levels of governance for a better planet and better lives. Consequently, achieving the “future we want” may be hindered by overlooking valuable natural resources and services that are not explicitly included in the SDGs. Not recognizing the direct, intrinsic value of some natural resources may threaten the sustainability of the services they provide and their contributions to the SDGs. Here, we use inland aquatic ecosystems, and the fish and fisheries therein, as an example to explore opportunities for recognition and inclusion of other natural resources that are missing from the SDGs. Key resources absent from the SDGs are less likely to be incorporated in global, national, and regional objectives, dialogues, and policies. We outline multiple potential pathways for better inclusion and capitalization of contributions from these overlooked natural resources during the operationalization of the SDGs and other global instruments.

Frontiers in Environmental Science

Ecological and social strategies for managing fisheries using the Resist-Accept-Direct (RAD) framework

Fisheries management is a complex task made even more challenging by rapid and unprecedented socioecological transformations associated with climate change. The Resist-Accept-Direct (RAD) framework can be a useful tool to support fisheries management in facing the high uncertainty and variability associated with aquatic ecosystem transformations. Here, RAD strategies are presented to address ecological goals for aquatic ecosystems and social goals for fisheries. These strategies are mapped on a controllability matrix which explores the ability to guide a system's behaviour towards a desired state based on ecological responsiveness and societal receptivity to change. Understanding and improving the controllability of aquatic systems and fisheries can help managers to maintain the broadest suite of available RAD management strategies.

Fisheries Management and Ecology

A Resist-Accept-Direct decision-support tool for walleye Sander vitreus (Mitchill) management in Wisconsin

Large-scale modelling and prediction provide insight into general influences of climate change on inland recreational fisheries; however, small-scale dynamics and local expertise will be key in developing explicit goals for managing recreational fisheries as the climate changes. The resist-accept-direct (RAD) framework encompasses the entire decision space managers consider when addressing climate influences in their local system, but to decide whether to resist, accept or direct, managers need tools to understand how specific waterbodies will be influenced by climate change. Here, a decision-support tool was developed and applied to the walleye recreational fishery in Wisconsin, USA as an example of how to link the RAD framework to real-world management of a large recreational fishery. The tool and broadscale results described here, indicating a widespread shift away from resist strategies by mid-century, can be used by managers to inform decisions about whether to resist, accept, or direct for specific walleye populations.

Wisconsin