Fish and Fisheries最新文献

Spatio-temporal species distribution models can support fisheries assessments and management in marine and freshwater environments. However, the high costs of structured surveys often limit the spatio-temporal coverage of the data available for modelling. To address this issue, we present a spatio-temporal modelling approach integrating structured survey data with unstructured presence-only data, which have greater spatio-temporal coverage than structured data, but are often disregarded in fisheries research. Data integration is achieved by generating pseudo-absences for the presence-only data and estimating spatially varying catchability for all data sources relative to the structured dataset. We consider a freshwater application, building longfin eel (Anguilla dieffenbachii, Anguillidae) spatio-temporal distribution models for the Taranaki region, New Zealand, and a marine application, building spatial density models for the vulnerable marine ecosystem indicator taxon Demospongiae in the South Pacific Ocean. We also conduct a simulation experiment to investigate the impacts of using pseudo-absences that do not reflect true absence patterns in our modelling framework. By integrating unstructured presence-only data, our approach improves the spatio-temporal coverage of the data available for modelling. Our applications provide results consistent with previous modelling studies but also offer new insights into the distribution and density patterns of longfin eel and Demospongiae. The simulation experiment found greater error and poorer uncertainty characterisation in models that mis-specified true absence patterns. We recommend assessing spatial structure in presence-only data and generating spatially structured pseudo-absences that match this structure. Our approach has many potential applications, such as providing enhanced information to assist fisheries in assessments and management.

Indigenous Peoples have developed knowledge systems that foster respectful and reciprocal relations between humans and other-than-human beings, supporting resilient ecosystems and societies. Despite the impacts of colonisation, Indigenous Knowledge Systems (IKS) endure in many parts of the world, and there is growing recognition that IKS can strongly improve fisheries management. During the last 5 years, Fisheries and Oceans Canada (DFO), the federal institution responsible for managing Canada's fisheries, released policies and strategies intended to make fisheries management more inclusive of IKS. To measure progress in their implementation, we applied 13 semiquantitative indicators and qualitative analyses of IKS inclusivity to a sample of 78 public documents produced or co-produced by DFO to advise management decisions. Of these documents, ≈87% reported cases that did not meaningfully include Indigenous Peoples and their IKS, 9.0% reported cases in which Indigenous Peoples were included in some aspects of research but their IKS was not, ≈3% reported cases in which IKS contributed to objectives and elements of research design but the process privileged Western science over IKS, and only one document met a high standard for the pairing of IKS and Western science. The indicators that we developed in a Canadian context can be used, with locally appropriate revisions, to gauge the extent to which state governments in other countries are inclusive of IKS in fisheries management, thereby identifying shortcomings in law, policy, and practice and informing mitigation measures. Strengthening the inclusivity of IKS would enable more holistic approaches to fisheries management and benefit global conservation.

Artificial structures deployed in marine environments as reefs are often presumed to increase fish production. However, our literature review found a lack of evidence, with only 12 studies empirically quantifying secondary production at artificial reefs, and only three studies using a control site. We propose the forthcoming large-scale construction of offshore wind (OSW) energy structures presents a natural experiment to examine the ecological function of artificial reefs, including their effects on fish production. To provide causal inferences of OSW effects, studies must obtain appropriate ‘before’ data, per before-after-control-impact and related designs. This requirement dictates that society must begin planning and collecting data now, prior to OSW deployment. We also highlight that responses beyond fish biomass measures, including life stage specific survival, site fidelity and trophic dynamics, must occur at appropriate spatial and temporal scales to maximise causal inference. By leveraging a timely opportunity and natural experiment with OSW development, the long-running ‘attraction–production debate’ about artificial reef ecological function may be addressed.

The European eel (Anguilla anguilla L.) has a catadromous life cycle, with a single panmictic population that colonises continental Europe and northern Africa yet migrates 5000 to 9000 km to spawn in the Atlantic Ocean. It is unknown how this continental migration is organised so individual eels arrive in time for spawning with conspecifics. This meta-analysis combined tracking data from 18 water bodies in freshwater and transitional systems distributed along the southwest-northeast axis of Europe, resulting in a dataset of 2306 eels, making it the most comprehensive in terms of geographical coverage and number of eels tagged. The eels were tracked using acoustic telemetry and the Nedap Trail System and allowed us to study the eel's migration phenology at a continental scale. The findings reveal that the day when eels arrive at sea varies significantly with latitude, with northern eels arriving earlier. Migration speed differs between tidal and non-tidal habitats, suggesting that tidal currents facilitate faster movement. However, despite these patterns, we observed substantial variability in arrival at sea time and migration speed within water bodies, suggesting that the eel's migration phenology is considerably plastic. The presence of water regulating structures such as weirs, pumping stations and hydropower plants can impact migration timing and speed, potentially delaying eels, but is likely dependent on local hydrological conditions which can be water body specific.

The growing use of data-poor fisheries models provides unprecedented access to compelling stock metrics and management scenarios for coral-reef fisheries. Yet, it remains unclear how well the assumptions surrounding data-poor models derived from extensive cold-water fisheries fit the life histories and ecology of tropical coral-reef fishes. The present study compared the outcomes from length-based spawning potential ratio (LBSPR) models versus observed trends from a novel meta-analysis of nine fisheries-independent (FI) and fisheries-dependent (FD) data streams across Micronesia. Thirty target species that comprised over 70% of landings were examined across temporal and spatial fishing pressure gradients associated with FI and FD streams. Cluster analyses using normalised effect sizes from over 140 statistical tests grouped the stocks based on the magnitudes of decline in (proportional) biomass and size-structure. Interestingly, many species with the greatest declines had modelled SPR and fishing mortality outcomes that did not trigger management based on established thresholds. These inconsistencies were attributed to several factors: variable compensatory density dependence across species, rapid growth over short time periods for small-bodied species leading to hyper-sensitive switch points in SPR metrics, and unusually long lifespans that did not always correlate with body sizes or growth rates. The complexity of life histories appeared to limit the use of snapshot data-poor models for depicting relative stock status across species; however, data-poor outcomes through time for each species better aligned with FI and FD trends. We generalise management guidance for a common and dominant group of tropical Pacific species.

This review examines the progression of fish bioacoustics and ecoacoustics, with a focus on the growing application of Passive Acoustic Monitoring (PAM) as a non-invasive tool for assessing fish biodiversity. As environmental conservation goals intensify globally, particularly with initiatives such as Biodiversity Net Gain, the need for effective methods to monitor aquatic biodiversity has become increasingly critical. PAM provides a scalable approach for tracking fish species, community structures and population dynamics across diverse habitats, addressing many limitations of traditional monitoring techniques. By cataloguing species-specific acoustic signatures, PAM enables long-term monitoring of fish biodiversity, which is crucial for conservation in remote and dynamic aquatic environments. Despite ongoing challenges – such as distinguishing species with overlapping acoustic niches, managing large datasets and ensuring the precise classification of sound types – recent advancements in artificial intelligence offer promising solutions. These technologies help balance the trade-off between analytical efficiency and the ecological and biological significance necessary for effective management and conservation. This review presents an overview of the thematic structure and temporal evolution of the field of fish bioacoustics and ecoacoustics and discusses future directions for the field to support sustainable ecosystem management and biodiversity conservation.

Mixed-species fish shoals are common, and form for a variety of reasons. We suggest that short term mixed-species shoals, that persist for minutes or hours, might form because lone individuals (or small groups) of one species might benefit from joining larger groups of heterospecifics to reduce predation risk. We carried out a literature survey, which revealed that mixed-species groups seldom contain equal numbers of species; rather one or two dominate, with others present as small minorities. Furthermore, we found that the proportion of minority species decreases as absolute shoal size increases. We suggest that although minority members of mixed-species groups might suffer costs associated with being odd, they might often still do better by grouping than if they remained alone. We term this ‘any port in a storm’. This explanation makes several predictions and assumptions, and we suggest approaches for testing these. For example, minority members should attempt to form single-species groups when the opportunity arises, and mixed species-groups should coincide with periods of heightened predation risk. Mixed-species groups may be influenced by the distribution of shelter, and further work is needed to disentangle the relative importance of aggregation versus social attraction in the formation of mixed-species-shoals. This account of mixed-species groups does not exclude other ecological functions, such as forager-guild formation, but may explain cases of short-term associations of minority species with numerically dominant species in fish shoals. Our predictions are readily testable, and we hope they spur further research in this area.

Targeted management interventions can influence marine resource user behaviour, yet some remain ineffective. Behavioural economics may offer valuable insights on this topic by identifying which interventions can effectively change human behaviour and how they can be applied. This systematic review (N = 140) synthesises evidence from behavioural economics studies conducted in a fisheries context. The results include a table of behavioural mechanisms and examples of evidence for behavioural interventions changing environmental, economic, and social outcomes. There is a growing body of evidence that interventions that activate mechanisms such as social norms or risk aversion can impact environmental outcomes. However, there is a general lack of explicit reporting of the link between behavioural mechanisms, interventions, and outcomes, revealing weak conceptualisation in the field. This hinders the ability of scientists, practitioners, and policymakers to derive actionable insights from the research. Furthermore, the ethics of intervening in human behaviour as well as thorough analysis of unintended consequences need significant attention. To resolve these issues and guide the field forward, this systematic review offers recommendations for both science and policy as well as a conceptual framework that can improve the design of future studies that aim to understand human behaviour in a fisheries setting.