Small pelagic fish (SPF) forage near the base of the food web in marine and inland waters. Changes in prey availability can have marked consequences on the productivity of populations of predators. Understanding environmental drivers of the dynamics of SPF populations, therefore, requires knowledge of the abiotic and biotic processes regulating SPF prey fields as well as robust estimates of diet and prey requirements. Moreover, top-down (predation) effects of SPF and their competitors may be just as important as bottom-up (abiotic) impacts in controlling the availability of prey. Future changes in predator–prey interactions depend on a complex array of individual factors affecting physiological rates and the strengths of associations between species. Although aspects of the trophodynamics of SPF have been studied for decades, gaps in knowledge still exist on important aspects of SPF diets, including prey quality requirements for the growth and survival of early life stages, ontogenetic diet shifts, and feedback between the changes in prey field dynamics and reproduction.

This session welcomes presentations on all aspects of trophodynamic processes involving SPF in marine and inland waters, particularly:

1. The impact(s) of environmental drivers on the phenology, abundance and composition of key prey taxa, novel diet studies, and/or processes impacting rates of feeding, competition, and predation;
2. Comparative studies focusing on trophic overlaps between SPF and other planktivorous species; especially, studies investigating climate-driven and/or density-dependent processes or the impacts of environmental drivers;
3. Studies exploring novel techniques in the quantitative and qualitative analyses of SPF trophic ecology in marine and/or inland waters such as numerical modelling or molecular or biochemical techniques (e.g., from genetic, eDNA, fatty acid, or stable isotopic analyses).

Intrinsic (individual-level physiology and population-level density-dependence) and extrinsic (environment, both abiotic and biotic) factors interact to shape time-varying changes in the small pelagic fish (SPF) abundance and/or distribution that can differ across life stages. This mechanistic understanding of how and why different life stages vary in space and time is a classical avenue of research that is now benefitting from the perspectives offered by new technologies, spanning from molecular techniques, new modelling approaches, and laboratory experiments exploring interacting pressures. This session encourages presentations that advance process understanding of SPF life cycle closure, with emphasis on spatial ecology and life history strategies. Studies that focus particularly on processes affecting early life stages, from eggs to juveniles (growth, connectivity, density-dependence, recruitment), as well as research on adult stages (e.g., maturation, fecundity, migration), are welcome.

This session invites contributions from marine and inland systems that particularly focus on:

1. Spatially-explicit research with relevance for management, including individual-based modelling, trait analysis as linked to spatial dynamics, etc.;
2. Studies on species/population acclimation (plastic response) or genetic adaptation based either on molecular, rearing or modelling experiments;
3. Studies that compare traits (growth, reproduction and survival) and mechanisms (extrinsic, intrinsic) explaining life cycle closure and habitat utilisation/connectivity at different scales in space and time, in particular across regions or under different climate regimes.

The responses of fish stocks to changing environmental conditions can have impacts at various time scales with consequences for a broad range of population characteristics. Although we strive to predict shifts in phenology and spatial distribution, such changes can also complicate efforts to understand the relationships between fish populations and environmental forcing, challenging our ability to predict future changes. Further hindering our efforts is the fact that the strengths of relationships among environmental drivers and population traits often change over time. These non-stationarities, both at the level of fish stocks and in a broader ecosystem context, are exemplified by tipping points between ecological regimes and/or rapid shifts in species dominance. These changes could be due to extrinsic factors linked to climate variability and atmospheric forcing, and/or intrinsic factors such as changes in animal behaviour or adaptation to new conditions. The consistency of shifts across ecosystems and regions is a harbinger of global-level threats to the resiliency of populations and ecosystems. This session aims to explore resilience in the context of non-stationarity (e.g., tipping points, shifts in inter-specific relationships, phenological mismatches between trophic levels, non-linear reactions to environmental forcing), both at the level of stocks and in a broader ecosystem context. In this context, defining and evaluating resilience becomes an important consideration, both for stocks and for fisheries.

This session encourages presentations that intend to understand the spatio-temporal variability in small pelagic fish (SPF) using one or several of the following approaches:

1. Re-analyses or short-term forecasts of phenological shifts in key aspects of life cycles such as spawning or migration;
2. Novel strategies to evaluate shifts in phenology, including assessment of the oceanographic, biogeochemical, or ecological drivers;
3. The relationship between SPF and ecosystem-level tipping points;
4. Perspectives on ways to define, evaluate, monitor, and promote stock and fishery resilience in the context of stock movement and boom-and-bust dynamics and in the context of the resilience of ecological functions.

Various strategies have been applied to resolve the impacts of climate and oceanographic conditions on populations of small pelagic fish (SPF). Sediment records, acoustic surveys, ichthyoplankton collections, fisheries landings, modelling experiments, and other fisheries-dependent and independent data provide some insight regarding the responses of fish populations to changes in the environment. However, each of these methods has caveats regarding the time and spatial scales that it can accurately address. Hypotheses developed through examination of historical landings records can be substantially different from those developed through investigation of sedimentary records. Similarly, because patterns of large-scale climate variability can have ecosystem impacts that differ in intensity among and within regions, examination of oceanographic data collected at local scales can provide perspectives divergent from those offered by consideration of basin-scale conditions. Reconciling the different (and sometimes contrasting) perspectives offered by various methods remains a challenge. Our understanding of population responses to climate conditions may benefit from multi-disciplinary approaches that appreciate this scale dependency and the potential for non-stationarity among relationships through time. Linking knowledge of species’ ecologies (e.g., recruitment, growth, feeding, distribution, migration, and spawning) with descriptions of changing environments by using both conceptual and numerical models can further help to resolve species’ sensitivities to climate variability and change.

This session welcomes presentations that:

1. Use information from multi-disciplinary approaches to better resolve the responses of SPF species to climate variability during paleo, observational, and future time periods;
2. Highlight divergent perspectives and propose hypotheses that might reconcile differing views;
3. Recognize that relationships among SPF populations and environmental conditions may be non-stationary across periods or when viewed at different spatio-temporal scales;
4. Discuss of how insight offered by paleo and observational records can be applied to better project SPF population responses to future anthropogenic climate change.

Directed surveys are a crucial part of monitoring and scientific assessment of small pelagic fish (SPF). Acoustic, egg, and larval survey programs have been conducted on a wide range of SPF species in many regions of the world since the 1970s. Early fisheries surveys often focused on a single target species with limited information collected on the physical environment and other pelagic ecosystem components. Vast technological advances and increased recognition of the need for robust advice to inform fisheries management on environmental drivers, including climate change, have resulted in improvements in survey methodologies. Modern surveys are increasingly becoming holistic enterprises that deliver a comprehensive set of in situ observations on different biological, physical, and chemical components of the pelagic ecosystem. Together with sophisticated modelling approaches and remotely sensed data, surveys are providing important new insights on the structure and function of pelagic ecosystems. The design and outputs of surveys vary according to their purpose and depend on the platforms, equipment, and expertise available. These differences hamper robust comparisons of SPF dynamics among ecosystems. Moreover, information from fisheries may be an important supplement to information gained from traditional surveys. It is becoming increasingly important that information and products from all parts of the survey process are shared with all stakeholders (from other researchers, the industry, to the broader community). This transparency ensures that survey methodologies are developed within a quality assurance framework that meets both accreditation criteria and community expectations regarding access to knowledge derived from publicly-funded research.

This session invites presentations on all aspects of surveys targeting pelagic fish species in marine and inland waters, including:

1. New technologies, approaches (e.g., survey design, data processing, autonomous vehicles) and products;
2. Biomass estimation – improving accuracy and precision, alternative indicators of stock status, use in stock assessments;
3. Climate change-induced challenges to survey design and products;
4. Incorporation of industry data to supplement traditional survey data;
5. Ecosystem-based approaches, integrated monitoring, modelling, survey products for ecosystem assessment.

Ecosystem-based fisheries management plans for small pelagic fish (SPF) must often reconcile the role of these species in marine and inland food webs as well as their economic and social value as a harvested resource. Natural, environmentally driven fluctuations in SPF pose an additional challenge to the sustainable use and management of SPF production. In this session, we welcome presentations regarding management approaches that help ensure sustained ecosystem services from marine and inland SPF stocks, including both harvest and forage provision for predators. In addition, ecosystem modelling and management strategy evaluations that allow testing new approaches, such as spatial management, improved monitoring and recruitment forecasts, or alternative harvest strategies, are encouraged. One goal of the session is to identify success stories from particular regions, with careful consideration about how that success can be replicated.

The session hopes to attract studies addressing:

1. Approaches that can integrate long-term climate change and short-term environmental variability into management and whether/how these approaches differ;
2. Trade-offs between assuring ecosystem needs of predators versus yields of SPF, and performance indicators and reference points representing these trade-offs;
3. Quantifying the dynamic role of SPF within the ecosystem, and inter-annual changes in dominant populations drivers (e.g., fishing versus climate drivers);
4. The utility of ecosystem models to evaluate multiple drivers of fish stocks and/or test management strategies and the best practice of using ecosystem models (e.g., quantifying ranges of uncertainty, measuring model skill, and including information into assessment and management);
5. Assessing and managing fluctuating stocks of SPF in data-limited situations;
6. Integrating indicators and ecosystem data, coming either from direct monitoring from the fishing industry or from surveys, into SPF management and related ecosystem modelling.

Small pelagic fish (SPF) represent an essential source of highly nutritious food, particularly for the poorer and more vulnerable segments of society, and support livelihoods, including for women involved in post-harvest activities in developing countries. Moreover, SPF form the most commercially important fisheries resources globally. There is a constant and dynamic evolution of SPF fisheries to adapt to and respond to external drivers such as climate change and market demand, but a number of gaps in quantitative and qualitative knowledge exist on SPF fisheries at all levels: ecological, social, and economic. Science-based advice for management, therefore, requires not only information on the drivers of the natural dynamics of SPF (e.g., productivity regimes), but also on societal needs and requirements (e.g., economic and/or cultural). Considering the increasing momentum on sustainability (Sustainable Development Goals, FAO Declaration on Fisheries Sustainability), this session takes stock of progress made in the use and management of SPF, including demonstrating how new technologies and tools fill knowledge gaps in the context of global change. The session also invites presentations on how information has been gathered from dependent human communities and used to advance various social-ecological analyses. The session is expected to have a strong focus on marine and inland small-scale fisheries, SDG 14.b (access for small-scale artisanal fishers to marine resources and markets), and to contribute to the generation of knowledge that will inform the International Year of Artisanal Fisheries and Aquaculture (IYAFA) that will be celebrated in 2022.

This session welcomes presentations on SPF in marine and inland waters that:

1. Quantify and characterize the reliance of coastal communities on SPF for nutrition, food security, and employment;
2. Advance management and governance arrangements (e.g., management plans, implementation of Ecosystem Approach to Fisheries, regional approaches) impacting access to SPF resources;
3. Examine access to markets including recent trends in processing, marketing and use of SPF (e.g. inter-regional and international fish markets, reduction for feed, changes in value chains);
4. Report on climate vulnerability/risk assessments, adaptation measures, and strategies focused on SPF throughout the value chain as well as economic tipping points.