Wiley: Fish and Fisheries: Table of Contents

Addressing Bias in Non‐Probability Fisheries Surveys Using Multilevel Regression and Poststratification Approaches

Fri, 19 Jun 2026 10:52:07 -0700

ABSTRACT

Quantifying harvest of fish stocks is challenging as census data are often unavailable, so surveys are required. Traditional probability-based surveys use random sampling to obtain representative data that can be scaled to estimate total impact. However, these surveys are costly, so cheaper, non-probability, citizen science surveys of self-selected participants are becoming commonplace. Respondents in these surveys may not be representative and inclusion probabilities are unknown, making weighting difficult. This resembles exit polls, which successfully predict election outcomes using Multi-level Regression and Post-stratification (MRP), but this has not been tested in fisheries. This study applied MRP to quantify UK recreational sea angling (RSA) participation and catches using data from the UK Sea Angling Diary Project. This represents a ‘worst-case’ scenario, as there is no sampling frame and no mandatory reporting. Five Bayesian multi-level models were fitted to two survey datasets: one quantifying participation and days fished, and another location, numbers, and weight of fish caught. Predictions were post-stratified using UK census data. Estimates from the traditional reweighting and MRP were compared, and a simulation approach was used to assess the accuracy and precision of the two methods. MRP reduced self-selection bias and improved estimates in under-represented groups, producing a 40% and 61% improvement for participation and catch, respectively. Average annual UK RSA participation was estimated to be 688,000 anglers, with 6.1 million days fished. Annual catch estimates were 32.4 million fish, weighing 14,876 t. This study demonstrates the value of MRP for reducing bias when analysing and scaling non-probabilistically collected survey data.

Management Participants Perceive That Structural Barriers, Not Information Needs, Most Impede Adaptation in U.S. Fisheries Management

Fri, 19 Jun 2026 10:50:37 -0700

ABSTRACT

Fisheries are facing increasingly frequent and severe climate change-related stressors such as marine heatwaves, harmful algal blooms, and species distribution shifts. Many fisheries management bodies have been working to increase the capacity of their regulatory systems to adapt to these new conditions, but progress has been slow and piecemeal. To identify the most important barriers to this adaptation, in spring 2024 we surveyed 321 fisheries management professionals and fisheries scientists involved in the U.S. regional fisheries management system. This survey revealed broad agreement among respondents about the most and least important barriers to adaptation, regardless of respondents' regional affiliation or role in the management system. In particular, two key barriers emerged as being salient to almost all survey respondents. These barriers were stakeholders focusing on protecting their current interests and/or the status quo (82% agreement) and a tension between the structural rigidity of the U.S. fisheries management system and the flexibility needed to adapt (71.5%). In contrast, conceptual and informational barriers, such as not seeing a need to adapt (4% agreement) and not recognizing the usefulness of adaptive capacity concepts (14% agreement), were the least salient across regions and roles in management. These results suggest that successful climate adaptation will depend on tackling difficult structural challenges, such as developing more flexible regulatory systems and creating mechanisms to address concerns and resistance by stakeholders who expect to incur losses in the process of adaptation.

Issue Information

Tue, 09 Jun 2026 07:40:12 -0700

Fish and Fisheries, Volume 27, Issue 4, July 2026.

An Emergent Seafood Nationalism Takes Hold in the United States

Owen Temby — Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

This paper introduces the concept of ‘seafood nationalism’ to describe how, since 2024–2025, the United States increasingly uses tariffs, trade remedies, food safety enforcement and origin-based rules to favour American seafood over foreign products. Federal actions include Executive Order 14276, Restoring American Seafood Competitiveness, which directs agencies to address unfair trade practices, unsafe imports and to develop a coordinated seafood trade strategy. Additional measures include a tariff package imposing a 10% duty on nearly all seafood imports and 30% on seafood from China, as well as new anti-dumping and countervailing duty orders on warm-water shrimp. This paper presents Gulf shrimp as a clear example of ‘shrimp survival nationalism’, which reflects nationalism from a position of weakness in a global commodity chain. Similar combinations of tariffs, labelling and safety rules are evident in the cases of catfish, crawfish, Alaska seafood and tuna. Drawing on research in gastronationalism and resource nationalism, this paper argues that these policies reframe seafood as a national asset to be protected rather than as a generic traded commodity. For fisheries science, this means that prices, trade rules and food safety standards can no longer be considered external market conditions. Including seafood nationalism in modelling and governance analysis reveals how politically driven changes in tariffs, import bans, labelling laws and safety enforcement alter incentives, redistribute benefits and harms, and complicate cooperation across fisheries and countries.

Advancing Ecological Understanding and Sustainable Management of Small Pelagic Fish

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Small pelagic fish (SPF) are critical to the trophodynamic structure and function of marine systems and support some of the most valuable and socially important fisheries worldwide. Their “boom and bust” population dynamics, shifts in distribution, and importance as forage resources for other fish stocks place unique challenges to assessing and managing SPF. In response to these challenges, an international working group was formed in 2019 to foster collaboration aimed at closing key knowledge gaps in the ecology and sustainable management of SPF. Here, that group reviews progress made over the last ~10 years and identifies priorities for the next stage of coordinated international collaboration. Key research needs include: (i) enhancing monitoring programs to capture shifts in SPF distribution and incorporating new technologies, from molecular tools and digital imaging to biophysical and ecological modelling, (ii) improving data sharing to better understand life-history bottlenecks and cross-regional population dynamics, (iii) advancing process-based studies on oceanic and trophodynamic interactions to clarify the ecological roles of SPF as both predators and prey, and (iv) conducting bioeconomic and risk analyses to assess the vulnerability of fishing-dependent human communities to environmental and fish population fluctuations. A key pathway forward involves integrating mechanistic ecological knowledge, ecosystem and bioeconomic modelling, and social-ecological frameworks into real-time, adaptive, and equitable management approaches. This integration will be essential for developing resilient, ecosystem-based fisheries management capable of anticipating tipping points, accommodating non-stationary population dynamics, and ensuring sustainability under future climate and socio-economic uncertainties.

Deep Dark Futures: Foresighting Human Impacts on Mesopelagic Ecosystem Services

Tue, 09 Jun 2026 07:40:12 -0700

This study uses foresighting to explore four plausible future scenarios of human activity affecting mesopelagic ecosystem services; provisioning, regulating, supporting and cultural. Using participatory scenario development, qualitative network modelling and indicator design, we assess systemic risks and early warning signals linked to harvest, climate mitigation, geopolitical manoeuvring and mineral extraction.

ABSTRACT

Most of the global mesopelagic zone lies beyond the jurisdiction of any single government or entity, making equitable access and sustainable management for ecosystem services (ES) difficult. Here, a foresighting approach was used to examine the plausible consequences of four speculative scenarios of human activity on the mesopelagic zone and its associated ES. Large-scale Harvest represented the provisioning ES, with concerns over unsustainable removal of mesopelagic biota. Climate Mitigation, a regulating ES, involved harvesting and then dumping mesopelagic biota to maximise carbon drawdown. In Geopolitical Manoeuvring, the scenario focused on cultural ES; mesopelagic fisheries were used as a geopolitical instrument to assert claims over ocean spaces. Finally, Mineral Extraction, a supporting ES, considered the impact of deep-sea mining on mesopelagic ecosystems. Drivers and indicators for each scenario were identified, and qualitative network models were created to assess impact on the different system components using press perturbations. Model outputs highlighted the central role that mesopelagic biota play in supporting and regulating other ecosystem components and the likely negative impacts of reduced biomass on higher order predators and ocean carbon storage. Interestingly, biological indicators performed poorly as early warning signals of change across all scenarios; instead, the most effective indicators were related to science and technology, economics and governance. International agreements for sustainable use of the mesopelagic zone are needed to avoid loss of ES underpinning all scenarios. While this foresighting focused on the mesopelagic zone, the approach of developing scenarios, models and indicators has broader applicability to studies of other systems.

Species Specificity in Fish Sounds: Evidence, Limits and Methodological Implications

Eric Parmentier, Marine Banse — Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Acoustic communication is now recognised as a widespread and functionally important component of fish behaviour. However, its evolutionary interpretation remains fragmented, as different types of acoustic signals are not interpreted with the same level of confidence. In particular, sounds recorded under disturbance or from hand-held individuals are widely used in comparative studies but remain debated in evolutionary contexts. Here, we re-examine these limitations by reviewing empirical, mechanistic and behavioural evidence across a wide range of teleost taxa. We show that interspecific acoustic differences are not restricted to reproductive contexts and that sounds obtained under disturbance can reflect intrinsic species-level properties of neural control, musculature and sound-producing structures. At the same time, we highlight that acoustic species specificity has not been demonstrated as a general rule across fishes, nor does sound alone constitute a universal prezygotic barrier. By integrating behavioural context, sound-production mechanisms and recording methodologies, this review provides a framework to interpret acoustic variation in an evolutionary context and clarifies the scope, limits and evolutionary relevance of different acoustic datasets.

Assessing Risk for Bycatch and Byproduct Species Using a Modified Sustainability Assessment for Fishing Effects (SAFE) Approach

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Central to ecosystem-based fisheries management is ensuring the sustainability of bycatch and byproduct species. However, the sustainability of these species is difficult to assess as the lack of information limits the use of traditional stock assessment methods. We demonstrate, using a complex multi-species fisheries exemplar, the efficient assessment of large numbers of diverse species, using a modified Sustainability Assessment for Fishing Effects (SAFE) approach. Applying this technique to 256 teleost and elasmobranch species caught in Australia's Northern Territory Demersal and Timor Reef Fisheries, we first applied an initial screening assessment to identify at-risk species followed by a secondary SAFE assessment for a more detailed evaluation. To enhance the precision of the secondary assessment, we incorporated species distribution modelling and refined fishing footprint estimates through spatial analysis of trawl paths, from vessel monitoring system data. Additionally, we integrated Monte Carlo simulations into the SAFE process to quantify uncertainties in fishing footprint and capture efficiency parameters. The conservative criteria applied in the initial screening process assessed 208 species as low-risk, with the remaining 48 species evaluated through our modified secondary SAFE approach. These 48 species were also subsequently classified as low-risk. Our approach adds steps to the SAFE process but enables us to efficiently assess large numbers of diverse species and thereby allows resources to be allocated to those species most at-risk. This adaptable approach is readily modifiable for application in other fisheries, including those with no or limited effort and catch data.

Environment‐Recruitment Relationships May Be Shadows of Other Life‐History Processes

Matthew D. Robertson, Paul M. Regular — Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Despite over a century of fisheries research focused on identifying environment-recruitment relationships, robust and long-standing relationships remain elusive, and the prevalence of ephemeral relationships has raised doubts about their utility for explaining recruitment. However, what if these relationships are shadows of other life-history processes? To explore this question, we simulated populations where the environment affects natural mortality, a life-history process often assumed to be constant, to determine whether spurious environment-recruitment relationships arise. Specifically, we produced a series of simulations in which the environment affects only one life-history process, while estimation models were misspecified with respect to which process was environmentally driven. Our simulations show that misspecified models consistently produce false detections of environmental effects on recruitment when the environment affects only natural mortality. These results indicate that previously identified environment-recruitment relationships that later broke down may have been artifacts of environmental effects acting on other life-history processes that were assumed to be constant. Focusing exclusively on recruitment may therefore obscure the true pathways through which environmental variability influences population dynamics. Ultimately, sound scientific advice in the face of marine ecosystem complexity requires hypothesis driven model comparisons and transparent model assumptions.

Implications of Maternal Toxicant Effects on Size‐Dependent Fisheries' Management: A Meta‐Analysis

Brandon M. Sosa, Christopher R. Malinowski, Tomas O. Höök — Tue, 09 Jun 2026 07:40:12 -0700

Larger, older fish transfer higher mercury and PCB concentrations to their eggs, significantly reducing offspring hatching success, survival and growth rates in contaminated aquatic ecosystems. These findings suggest that the reproductive benefits of big old fat fecund female fish may be compromised by maternal toxicant transfer in polluted waters. *Note: trends for toxicant impacts on growth rate were inconsistent for PCBs across analytic approaches. Publication bias was detected for larval success analyses (hatching, survival and growth) and was adjusted for using the trim-and-fill approach.

ABSTRACT

Bioaccumulation of environmental toxicants in aquatic ecosystems presents a significant ecological challenge including potential implications for fish reproduction and population dynamics. Through this meta-analysis, we investigated how elevated mercury (Hg) and polychlorinated biphenyls (PCBs)—two prevalent and problematic contaminants—in large, and presumably old fish, affect toxicant concentrations in their eggs and subsequent offspring success. We synthesized published data to analyse: (1) the association between maternal size and egg toxicant loads, (2) the relationship between maternal muscle toxicant concentrations and egg toxicant loads and (3) the impact of egg toxicant loads on offspring hatching success, mortality and growth. Our results revealed that maternal size was strongly, positively associated with egg toxicant concentrations, with Hg showing an effect size nearly double that of PCBs. Similarly, toxicant concentrations in maternal muscle tissues were strongly, positively associated with egg concentrations for both contaminants. Additionally, elevated egg toxicant loads were associated with decreased hatching success and increased offspring mortality, whereas impacts on growth rates varied by toxicant, highlighting negative impacts on early life stages. These findings have important implications for fisheries management, particularly regarding the protection of ‘big old fat fecund female fish’ (BOFFFFs). Although BOFFFFs typically produce numerous eggs, our study shows these benefits may be offset by increased toxicant transfer to offspring in contaminated systems. Management strategies should consider the reproductive benefits of BOFFFFs and the potential disadvantages of maternal toxicant transfer when establishing conservation priorities, especially in historically or currently contaminated systems or populations more susceptible to bioaccumulation.

Using Stock Vulnerability to Evaluate Fishery‐Independent Survey Coverage and Inform Sampling Priorities

Derek G. Bolser, Lewis A. K. Barnett, Jason Cope — Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

The consequences of mis-managing vulnerable stocks (i.e., those with low productivity and high susceptibility to depletion) are high and potentially permanent. To support sustainable fisheries management, stock assessments can be improved by increasing the quantity and quality of fishery-independent survey (i.e., survey) data. Social and economic value typically determine sampling priorities, but high value stocks are not necessarily at the highest risk for depletion. So, we modified the Productivity-Susceptibility Analysis, a data-limited fishery assessment tool, to identify which stocks are most vulnerable to unpredicted stock depletion (due to overfishing, environmental stressors, or mis-management from unknown or mis-specified stock status). We examined the vulnerability of 426 fish stocks or species within stock complexes that NOAA Fisheries assessed from 2005 to 2024 (excluding highly migratory and salmon stocks). We then examined patterns of vulnerability by taxonomy, area and survey method. The most vulnerable stocks were demersal teleosts (e.g., Psychrolutids, Macrourids, Scorpaenids). On average, the Caribbean Sea, West Coast and Pacific Islands contained the most highly vulnerable un-sampled stocks. Visual surveys in Alaska sampled the most vulnerable stocks on average, followed by bottom trawl surveys in Alaska. Across all areas, bottom trawl surveys provided stock assessment information for nearly twice as many stocks as any other survey method on average. Data limitations can lead to large buffers around catch limits and whether highly vulnerable stocks are subject to directed fisheries or are constraining ‘choke’ stocks in others, considering stock vulnerability alongside social and economic value may lead to better fishery management outcomes.

Offspring Size Resolves a Population Growth Paradox in Rays and Skates

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

The maximum intrinsic population growth rate, r _max, is a key determinant of sustainable fishing limits and is increasingly used in risk assessments. We previously showed how the r _max of rays and skates (subclass Batoidea) scales with adult body size, temperature (and hence depth) such that smaller-bodied species and those in warmer, shallower waters have greater r _max and, therefore, will be less sensitive to overexploitation. Paradoxically however, warm shallow-water tropical rays have lower r _max than cold deepwater temperate skates, contra to the expectation from metabolic scaling theory. To resolve this paradox, we examine how r _max is related to adult and offspring size (while accounting for temperature and depth) across 85 ray and skate species. Offspring size mediates relationships between r _max, adult body size, temperature and depth. Despite inhabiting warmer, shallower waters, tropical rays generally have larger offspring and lower r _max compared to temperate skates. Our result explains why tropical rays are less resilient to overfishing despite expectations from metabolic theory that tropical species should have faster life histories and therefore higher r _max and greater resilience than temperate species. Although the drivers of large offspring size in tropical rays remain uncertain, we use basic models of temperature- and size-dependent predation to hypothesise that this is due to greater predation risk in shallow tropical waters selecting for increased maternal investment in offspring size via evolution in viviparity and matrotrophy. Our work highlights the complex relationships among life histories and the environment and may help explain global biogeographic patterns of intrinsic sensitivity to exploitation.

Causal Models as a Scientific Framework for Next‐Generation Ecosystem and Climate‐Linked Stock Assessments

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Rapid changes in marine ecosystems highlight the need to account for time-varying productivity in stock assessments used to support fisheries management. Common approaches incorporate annual variation or regressing processes such as recruitment, natural mortality, or growth on environmental variables. While the latter represents a step toward biological realism, it often fails to account for interactions among variables and may yield biased inferences when key drivers are correlated or unmeasured. We introduce a novel framework, Structural Causal Enhanced Stock Assessment Modelling (SCEAM), which integrates a Dynamic Structural Equation Model (DSEM) into a state-space stock assessment method. SCEAM encompasses and extends the full range of existing time-varying approaches within a single framework, enabling direct comparison among them. We applied SCEAM to walleye pollock (Gadus chalcogrammus) in the Gulf of Alaska to improve recruitment forecasting, comparing three causal models of increasing complexity to recruitment modelled as random deviations around a mean, a first order autoregressive process, or regressed on a single variable. We found that a causal model with intermediate complexity best balanced fit, parsimony, and predictive skill. This configuration reduced unexplained variance of recruitment by 69% and improved one-year-ahead forecasts. Key variables included juvenile body condition and juvenile and larval catch rates. Our study represents the first application of a structural causal model embedded within a fisheries population model. SCEAM offers a unified, hypothesis-driven approach for integrating multiple non-independent variables. We therefore propose that SCEAM serve as a general scientific and statistical framework for conducting next-generation ecosystem- and climate-linked fisheries stock assessments.

A Framework to Investigate the Effects of Observation Error on Neural Network Predictions of Fish Age

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Technological innovations for predicting fish age represent a paradigm shift from conventional age estimation methods used in fisheries science. Recently developed secondary methods rely on models trained on conventional age estimates, derived from subjective interpretation of growth patterns and a biological property of the fish to predict age. Hence, quantifying the error that propagates from these models and the conventional age estimates on which they are trained is critical to fully account for uncertainty in predicted ages used in fisheries stock assessments. We review the development of three secondary age prediction methods: image analysis, epigenetics and Fourier transform near-infrared spectroscopy (FT-NIRS); the use of artificial intelligence (AI) within each method; and present an approach to examine the effects of ageing error on AI age prediction models. As a case study, we conducted an empirical study, coupled with simulation, to quantify the effects of ageing error on the performance of a multimodal convolutional neural network (MMCNN) model used to predict eastern Bering Sea walleye pollock (Gadus chalcogrammus) ages from otoliths analysed using FT-NIRS. Results indicated repeatability of predicted ages was high between instrument operators, while adding ageing error resulted in a slight decrease in model performance from R ² = 0.92 and CV = 7.6% to R ² = 0.87 and CV = 10.2% on test datasets. Our results also suggest the MMCNN model is robust to noise in calibration age data and model performance may be better than performance metrics indicate when the model is evaluated against data with increased error.

Challenges and Opportunities for Strengthening Bottom‐Tow Fisheries Sustainability

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Bottom-tow gear fisheries (trawls and dredges) produce ~24 million mt of harvest annually, representing a globally important animal-sourced food system. While many are currently sustainably managed, growing concern over the potential for ecosystem impacts from bottom-tow gears has increased pressure to improve these fisheries. We assembled an international working group of > 30 contributors, including fishing industry participants, managers, non-governmental ocean conservation organization representatives, and scientists to synthesize obstacles to bottom-tow fisheries sustainability and to develop expert-based recommendations to operationalize sustainability advancements moving forward. We identified 30 key gaps impeding bottom-towed fisheries sustainability spanning 6 core challenge areas including: seafloor disturbance, bycatch and discards, management design and implementation, fishing operations, cross-sector conflicts, and public perception and communication. We generated 28 priority recommendations to address bottom-tow fisheries sustainability obstacles with themes including: addressing data gaps, advancing mechanistic understanding and modelling tools, strengthening management processes, and improving knowledge sharing and communication. Cross-disciplinary and diverse system experience among fisheries and marine ecosystem stakeholders will be critical for operationalizing bottom-tow fisheries sustainability advancements. As the global human population approaches 10 bn in the next 30 years, ensuring sustainable wild capture fisheries is an imperative for feeding the world. Outputs from this synthesis serve as a resource for fishing and marine ecosystem stakeholders to identify key challenge areas and associated entry points for solutions-oriented efforts to improve the sustainability of bottom-tow fisheries.

Leveraging the Highly Data‐Rich Northeast Arctic Cod (Gadus morhua, Gadidae) to Identify Key Biophysical Factors Behind Recruitment Success

Tue, 09 Jun 2026 07:40:12 -0700

The recent markedly reduced recruitment success (recruitment per spawner stock biomass) of Northeast Arctic cod (Gadus morhua, Gadidae) is seemingly largely attributed to the joint negative effect of increased temperature and cannibalism but also predation on the postlarvae by Northeast Atlantic mackerel (Scomber scombrus, Scombridae). The near-future predictions under plausible scenarios reveal changes in recruitment by −21% to +16%, indicating a cautiously moderate outlook. These findings underscore the importance of maintaining precautionary management strategies for this largest cod stock.

ABSTRACT

Forecasting the number of individuals entering a fishery is critical for sustainable harvest and thereby management actions, but it remains challenging due to the considerable inter-annual variability and the complex nature of causal factors. This long-standing ‘recruitment problem’ has become even more urgent under ongoing climate change and the associated regime shifts overturning traditional predictive models. Leveraging the highly data-rich Northeast Arctic cod (Gadus morhua, Gadidae), this study proceeds beyond traditional data and method limitations. Such an initiative appears most timely because its recruitment (R), measured as number of 3-year-olds, is currently low and raising socio-economic concerns. We hypothesize a causal map and then apply Dynamic Structural Equation Model with sensitivity analyses to explore complex response patterns. The higher temperature exhibited a dual role: positive for spawning stock biomass (SSB) but negative for abundance of 1-year-olds (Age1) and R. Predation on postlarvae by northward-migrating Northeast Atlantic mackerel (Scomber scombrus, Scombridae), but not by herring (Clupea harengus, Clupeidae), appeared to influence Age1 negatively. As expected, fishing reduced SSB, whereas prey availability, represented by mesozooplankton biomass and stomach fullness, exerted a positive effect on Age1 and R. These suite of links remained robust, but shorter time series (< 30 years) may blur underlying patterns. Essentially, the low recruitment success (R/SSB) seen since 2010 (from the 2007 year class onwards) seems related to an overall poor situation for the 1-year-olds. Predictions give a less optimistic outlook and underline the high importance of maintaining today's advanced precautionary management strategies for this world's largest cod stock.

Reproductive Biology and Early Life History Inform Steepness and the Productivity of Rockfishes (Sebastes spp., Scorpaenidae) in the California Current

Sabrina G. Beyer, John C. Field, Marc Mangel — Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Steepness, a parameter derived from the stock-recruit relationship, is widely used in fishery stock assessments to scale the productivity of a population. Steepness is a highly influential parameter, but it is often unknown a priori and is typically difficult to estimate. Attempts to statistically estimate steepness, either within stock assessments or through meta-analyses, can lead to implausible results. We move beyond steepness as a statistical concept to emphasize that steepness is determined by life history traits and the early life survival of offspring of a population. We return to the original derivation of the Beverton-Holt stock-recruit relationship, and model recruitment to the population as a function of total egg production, rather than using spawning biomass as a proxy. We then demonstrate how to calculate steepness based on biology through a case study of rockfishes (Sebastes spp., Scorpaenidae) in the California Current, where steepness has been notoriously difficult to estimate. We leverage a wealth of reproductive ecology and early life history information (empirical data and associated life history parameters) to compute steepness values for four species of rockfishes, in order to illustrate how steepness varies by species based on differences in their life histories. We also show the sensitivity of steepness to the different life history traits. We conclude that steepness of a stock-recruit relationship is a real biological parameter and can be meaningfully informed with life history parameters including early life survival.

Worldwide Invasions of Centrarchidae: The Dark Side of the Sunfish Family

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Freshwater fish invasions are major drivers of global ecological change, disrupting native biodiversity and ecosystem functions. However, many invasive fish hold significant socioeconomic value, resulting in conflict over their management. Centrarchidae, which are globally distributed and are important for sportfishing and aquaculture, are now potentially becoming a global threat. Yet, no comprehensive appraisal exists across taxa and regions integrating taxonomy, pathways, impacts and risk analysis for Centrarchidae. To address these gaps, we compiled published literature and leveraged publicly available databases to critically evaluate the current global status of non-native Centrarchidae, finding 30 species established outside their native ranges with 17 being outside of North America. Largemouth bass (Micropterus nigricans) and pumpkinseed (Lepomis gibbosus) are the most widely introduced centrarchids. Reported impacts of Centrarchidae introduction are mostly ecological, with predation, competition, hybridisation, and disease transmission as major mechanisms. Conversely, socio-economic and cultural effects are underreported. Currently, only ten species have undergone rapid risk screening, with 90% flagged as high risk. However, risk analyses remain sparse, confounded by taxonomic uncertainties (including hybridisation) and context dependence of impacts. With the changing climate and other anthropogenic disturbances in freshwaters, habitat suitability is expanding for centrarchids. Although concerning, Centrarchidae form a highly human-mediated invasion complex with predictable pathways and tractable leverage points, so limiting propagule pressure and standardizing assessments can curb their future spread while informing balanced and evidence-based fisheries policy that reconciles socioeconomic benefits with environmental costs.

The Forgotten Pink Salmon in the Laurentian Great Lakes: An Unexpected Invasion With Insights for Three Oceans

Tue, 09 Jun 2026 07:40:12 -0700

ABSTRACT

Introductions of species outside their native range, such as pink salmon (Oncorhynchus gorbuscha) in the Laurentian Great Lakes, can serve as unplanned experiments that provide new insights into ecological adaptation. We synthesize available information on the understudied Great Lakes pink salmon invasion and highlight how this case can inform research and management related to expansions and invasions of this species in the Pacific, Arctic and North Atlantic Oceans. Accidentally introduced to Lake Superior in 1956, pink salmon quickly spread to all five Great Lakes, displaying unexpected behaviours and life history plasticity. This invasion history demonstrates a remarkable ability of pink salmon to establish from a small founder population, colonize large areas, produce explosive year classes to rapidly increase in abundance, and complete a full life cycle entirely in freshwater. One of the most striking changes is a shift from their rigid 2-year Pacific life cycle to a variable maturation age ranging from 1 to 4 years, likely influenced by prey availability as well as temperature and other environmental factors. We discuss implications for expansions elsewhere and outline five research themes necessary for understanding pink salmon dynamics in the Great Lakes with broader relevance for managing the species everywhere: (1) What drives rapid changes in abundance? (2) How do temperature extremes influence their ecology? (3) What causes departures from the 2-year life cycle? (4) How important is it for the phenology of life history events to match new habitats? (5) What guides pelagic movements and straying in new habitats?

Emerging Fisheries and Public Opinion: Insights From a Survey Experiment on Mesopelagic Fishing

Anna Lou Abatayo, Maartje Oostdijk, Andries Richter — Mon, 08 Jun 2026 11:05:52 -0700

ABSTRACT

Public acceptability of fisheries policy remains a key challenge for successful governance, constraining the set of feasible management options. To many, public opinion seems mysterious—rarely aligned with scientific evidence, yet not random, as it is shaped by frames, narratives and social factors. Here, we examine public acceptance of governing a new fishery through a survey experiment conducted in 10 countries. As a case, we consider the mesopelagic zone, a largely untapped resource with high biomass and economic potential. However, mesopelagic fishing also entails ecological and social risks, including impacts on food webs, carbon sequestration and global equity. Acceptance varied substantially across countries. Support was lower in wealthier countries, such as Germany and the Netherlands, where respondents also favoured stricter regulation, and higher in Indonesia, Nigeria, the Philippines, and, to a lesser extent, Spain, where support for regulation was weaker. Different frames have different effects across countries. For example, emphasizing risks to food webs reduced acceptance in Argentina and Nigeria, while highlighting disproportionate burdens on the Global South further lowered support only in Nigeria. At the individual level, confidence in government and large companies increased support for mesopelagic fishing, whereas other demographic factors played smaller roles. These findings emphasize the role of equity concerns and localized public opinion in shaping policy for fisheries and highlight the context-dependent power of narrative framing.

Advancing Automated Fish Size Estimation From Images: Applications, Challenges and a Case Study for Images Without a Specified Reference Object

Tue, 02 Jun 2026 22:41:42 -0700

ABSTRACT

Automatic and accurate estimation of fish sizes from images is essential for many monitoring, fisheries management, stock assessment and conservation efforts. However, current methods often rely on physical reference objects or stereo-camera systems that are not always available. This paper explores the advancements, applications and challenges of automated fish body-size estimation from images, using artificial intelligence (AI) and machine learning (ML) methods. We first introduce key concepts in AI and ML for a non-specialised audience and review existing literature on models used for fish size estimation. We identify key barriers such as a lack of high quality and publicly available datasets, image variability, scattered efforts and the challenges of model generalisation across diverse species. Then we present a novel framework for size estimation from monocular (non-stereo) images without a specified reference object, using a dataset from an angling app. Our approach utilises an efficient, pretrained deep learning-based feature extraction tool integrated with an automated regression pipeline. Our findings demonstrate a promising pathway for size estimation in images without a reference object, with most estimated fish lengths within 10% of their true length. Future research and collaborative efforts should focus on diversifying and sharing training data and integrating metadata. To this end, we created a user-friendly online application, where the community can test the model performance and contribute photos. Finally, it is essential to rigorously test and refine the robustness of current models in real-world fisheries applications and to adopt standardised, comparable metrics for evaluating fish size estimation models across studies.