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The need to transition from traditional single-species fisheries management approaches towards ecosystem-based fisheries management (EBFM), or an ecosystem approach to fisheries, is widely recognised. EBFM is particularly important when considering management actions for economically valuable fisheries for small pelagic forage fish, given their key ecological role. Management strategy evaluation (MSE) is an effective approach to advance the quantitative implementation of EBFM by enabling stakeholders to explore trade-offs among competing ecosystem-related objectives. This paper puts forward six different approaches to advance EBFM with MSE explicity, by taking advantage of data and research already available and by guiding future research. These approaches can be grouped into those which (i) involve the operating model and/or link directly to the operating model while potentially providing additional performance metrics to evaluate ecosystem objectives, (ii) can be incorporated into the performance metrics, and (iii) involve the harvest control rule of the management procedure. This review demonstrates that immediate steps can be taken to implement EBFM targeted at quantitative tactical management, even without a complex, data-rich ecosystem operating model. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Motivated by the leadership, scholarship, and activism of Indigenous Peoples, there are growing calls to transform and decolonize Canadian institutions that govern fisheries research in Canada. As a predominantly non-Indigenous group that works at the intersection of fisheries and justice, we encounter questions daily about how to act as allies in these efforts and take up this urgent call in our own work. Our goal with this perspective is to synthesize and share some of what we have learned about encountering and combatting colonialism in the hope that it may offer something to other non-Indigenous and settler fisheries researchers who are grappling with colonization in their own work. This synthesis is based on both Indigenous scholarship and our own experiential learning. We look to actions fisheries researchers may take to advance Indigenous sovereignty in fisheries research. We offer this to our fellow non-Indigenous researchers who likely also struggle with similar questions, and hope that in doing so, we can help move towards decolonial fisheries futures. [ABSTRACT FROM AUTHOR]

Small pelagic fishes occupy an important trophic role in every global aquatic ecosystem, and many species are heavily exploited by fisheries, including some of the largest and most valuable capture fisheries in the world. In November 2022, a symposium on small pelagic fish titled "Small Pelagic Fish: New Frontiers in Science and Sustainable Management" was cohosted by PICES, ICES, and FAO in Lisbon, Portugal. This special issue contains a collection of research manuscripts that explore approaches currently being used and developed to assess and manage small pelagic fishes. In particular, this issue covers topics on novel approaches to surveying small pelagic fishes, incorporating environmental covariates into management, management strategy evaluation, and aspects of the economics of small pelagic fisheries. The conclusions highlight the importance of new approaches that seek to enhance small pelagic fish surveys and ecosystem monitoring, incorporate that ecosystem information into management strategy evaluation, and predict the potential impacts of ecosystem changes on outcomes for economies and communities that rely on sustainable populations of small pelagic fishes. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plastic contamination extends across all Great Lakes ecosystems, including in wildlife, with the potential for risk based on laboratory experiments and risk assessment. Due to widespread contamination, and based on evidence suggesting measurable risk, it is time for policy-makers to develop and implement monitoring programs to guide management. Here, we discuss the need for a monitoring strategy with clear guidelines. We synthesize the research that has been published across the Great Lakes, reporting on contamination, regions that have been the focus of study, and the methods used across matrices. Based on our findings, we suggest how research may inform guidelines and next steps—especially if microplastics are to be considered as a toxic chemical sub-indicator under the Great Lakes Water Quality Agreement. Future monitoring, using standard and (or) harmonized protocols for sampling and analysis, should build baselines across the basin and begin tracking how contamination changes to assess the health of the Great Lakes, to inform source reduction, and to measure the effectiveness of policies aimed at reducing emissions of plastics to freshwater. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ciscoes (Coregonus spp.) were historically abundant and ecologically important in Laurentian Great Lakes ecosystems. Despite well-documented declines in their abundance and taxonomic diversity, declines in morphological diversity remain understudied. This knowledge gap is especially pertinent for lakes Michigan and Huron, which have each lost six of eight historical species. Improved understanding of historical and contemporary morphological diversity of Great Lakes ciscoes can inform ongoing restoration efforts and further elucidate the factors that contributed to declines. Our goal was to characterize shifts in morphological diversity of ciscoes in lakes Michigan and Huron over a century (1917–2019). We analyzed size-corrected morphometric and meristic measurements from three periods: Early (1917–1923), Middle (1950–1972), and Contemporary (2015–2019). We then identified morphologically distinct clusters while remaining agnostic to species identifications. We found that morphological diversity and the number of distinct clusters declined over time. We then leveraged species identifications to highlight key species losses and examine morphological shifts among extant species. Our findings provide insights into the historical and contemporary morphological diversity of ciscoes and will inform restoration efforts. [ABSTRACT FROM AUTHOR]

The bridle shiner (Notropis bifrenatus) is a small cyprinid native to the eastern United States and Canada. Bridle shiner populations have declined across their range, and the species now receives concern status or legal protection in 13 states and two provinces. Bridle shiners were historically found in southern and western Maine in densely vegetated, shallow habitats along the shorelines of streams and ponds. We surveyed areas of Maine that supported historical bridle shiner populations using environmental DNA (eDNA) and traditional seine netting methods, and then used eDNA sampling to survey areas with unknown bridle shiner presence. We rediscovered bridle shiner populations at 11 of 32 historically occupied waterbodies and documented bridle shiners in four additional waterbodies. We determined that both eDNA and seine net surveys are viable options for monitoring bridle shiners in Maine and identified ways to streamline the eDNA methods used in this study to reduce the time and cost of future surveys. [ABSTRACT FROM AUTHOR]

Accurately predicting species' distributions is critical for the management and conservation of fish and wildlife populations. Joint species distribution models (JSDMs) account for dependencies between species often ignored by traditional species distribution models. We evaluated how a JSDM approach could improve predictive strength for stream fish communities within large watersheds (the Chesapeake Bay Watershed, USA), using a cross-validation study of JSDMs fit to data from over 50 species. Our results suggest that conditional predictions from JSDMs have the potential to make large improvements in predictive accuracy for many species, particularly for more generalist species where single species models may not perform well. For some species there was no added explanatory effect from conditional information, most of which already exhibited strong marginal predictive ability. For several rare species there were significant improvements in occurrence predictions, while the results for two invasive species considered did not show the same improvements. Overall, the optimal number of species to condition upon, as well as the effects of conditioning upon an increasing number of species, varied widely among species. [ABSTRACT FROM AUTHOR]

Conservation planning requires understanding population sizes and trajectories. As with many imperiled species, green sturgeon (Acipenser medirostris) census data are limited, making it difficult to contextualize current threats and promote quantitative conservation goals. We combined spawning census, growth, and demographic data for the southern population of green sturgeon to build a population size and trajectory estimate. We generated a distribution of population size estimates and trajectories reflecting uncertainty from multiple sources. We then propagate these estimates through a demographic model to assess the potential impact of fishing bycatch. Our model suggests the population is below the recovery goal of 3000 adults. The most probable current total population estimate (including juveniles) is approximately 10 000 fish (5300–18 400 95% high density interval (HDI)), with 2400 adults (2197–2624 95% HDI). Simulated fishing bycatch pressure on the adults and subadults reduced abundance by a median value of 0.4% per year, which could be an impediment to recovery. Fisheries bycatch is one of many threats this population faces; this integrated framework may be used to assess how other threats may affect this population. [ABSTRACT FROM AUTHOR]

Biomass estimates of fish resources by the daily egg production method (DEPM) are sensitive to the high variability of the daily egg production (P0) and egg mortality (Z) in space. This work presents a Bayesian approach to estimate these parameters. A prior distribution of Z based on literature serves to overcome the biologically implausible Z estimates that can result from frequentist approaches. In addition to the classical estimation of a single P0 over the spawning area, the Bayesian framework allows also the modelling of egg densities in space, by including either spatial random effects, smoothing functions, or kriging like models, providing insights into the spatial variability of P0. The Bayesian approach was applied to the Bay of Biscay anchovy DEPM surveys. Results showed that this Bayesian approximation solved the implausible Z problem resulting in tighter credible intervals of both P0 and Z. Overall, spatial models outperformed the non-spatial model in terms of goodness of fit and resulted in slightly different total production estimates across models for each year, with a moderate decrease on uncertainty estimates. [ABSTRACT FROM AUTHOR]

Fishers often target multiple species. More diverse harvest portfolios may reduce income risk, increasing resilience to climate-driven changes in target species' spatial distributions and availability. Moreover, different effects can be observed across vessels in response to the same shocks and stressors, as fishers are heterogeneous. Evaluation of climate risk across different vessel groups within a particular fishery requires consideration of heterogeneous climate impacts on the availability of multiple target species and how such changes may impact substitution behavior. Here we analyze how historical climate-driven changes in forage species distribution and the closure of the Pacific sardine fishery affected landings per vessel of three coastal pelagic species (CPS): Pacific sardine (Sardinops sagax), market squid (Doryteuthis opalescens), and northern anchovy (Engraulis mordax) targeted by the U.S. West Coast CPS fleet from 2000 to 2020. Using cluster analysis, we grouped vessels into different fleet segments and estimated heterogeneous responses by fleet segment and port area. Our results show that considering heterogeneity is essential in the development of equitable and effective adaptation policies designed to mitigate the impact of changes on species availability in these fisheries. [ABSTRACT FROM AUTHOR]

Sprat are commercially valuable and are an important component of the North-East Atlantic ecosystem as major predators of zooplankton, competitors with herring, and prey for piscivorous fish, marine mammals, and seabirds. Despite this, insufficient information exists for Celtic Seas sprat, one of five North-East Atlantic stocks, to estimate stock status. To ensure the sustainable exploitation of sprat, the health of the Celtic Seas ecosystem, and the wider fisheries sector, we conduct a management strategy evaluation to stress test the current single-species advice framework. The aim is to evaluate whether ecosystem objectives can be achieved under single-species maximum sustainable yield and precautionary advice frameworks. An operating model was conditioned on life history theory and strategic information from ecosystem models. We showed that in-year advice using an empirical rule could achieve management objectives and help balance the trade-offs between fishing activities and ecosystem health. The approach allows ecosystem understanding to be incorporated within existing precautionary and maximum sustainable yield frameworks to provide a robust management framework that can meet multiple objectives despite uncertainty. [ABSTRACT FROM AUTHOR]

Krill (Euphausia superba), a small pelagic crustacean. is the largest food resource serving many predators in the Antarctic ecosystem. Given the recent slow expansion of the krill fishery, interest is increasing on how best to harvest krill without unduly impacting its natural predators. The Mori–Butterworth Antarctic ecosystem model attempted to explain the dynamics of the "major" predators through predator–prey interactions alone. That model considered blue, fin, humpback, and minke whales, and crabeater and Antarctic fur seals. Here, this model is expanded to include "minor" krill-predators, such as mackerel icefish. It focuses on a smaller scale, roughly corresponding to International Whaling Commission Management Area II. Results suggest a meaningful difference (historical abundance trajectories differing by more than 5% on average over time) when including "minor" predators. Hence, at an area-specific level, "minor" predators should be considered for further models of at least certain sectors of the Antarctic, as they may meaningfully influence the dynamics of krill and its "major" predators. This in turn could impact management decisions for the krill fishery, as regards optimal krill harvesting. [ABSTRACT FROM AUTHOR]

Temperature modifies the reproductive success of fish, yet, in many species, we lack the information on its role in the early development. In this study, the effect of temperature on the relation between maternal traits (length, age, somatic condition, and muscle lipid and ovarian thyroid hormone concentrations), egg quality (fertilization success, development rate, mortality, and hatching success), and offspring traits (size-at-hatch, yolk sac size, and proportion of malformations) were studied in Baltic herring (Clupea harengus membras) in the northern Baltic Sea. The experiments were conducted at an ambient temperature of 7 °C and at an elevated temperature of 14 °C using 5 to 10 females and 3 replicates per female. The results indicate that elevated temperature may result in a faster developmental rate, a lower early-stage mortality and hatching success, smaller size-at-hatch, a larger yolk sac size, and a higher amount of larval malformations when compared to an ambient temperature. The egg and offspring traits were also associated with the maternal traits, indicating especially that thyroid hormones play a mediating role in the physiological processes. [ABSTRACT FROM AUTHOR]

Survival through the larval phase is predicated on the probabilities of successful feeding, which dictates growth rates, and the probabilities of encountering predators. Here I perform a synthesis of feeding, growth, and mortality rates estimated during several studies from coastal Newfoundland, Canada, to provide a description of the probability distribution that can serve as a foundation of the expected distribution of vital rates. The standardized observations clearly follow that of skewed distributions, appropriately fit to a probability gamma distribution, with feeding demonstrating a stronger degree of skewness than either mortality or growth, possibly because each vital rate integrates prey–predator interactions over different time scales. Commonality in the underlying form of the distribution of vital rates in larval fish, along with clear functional relationships between gamma parameters, represents a probabilistic basis of expectations against which observations from prior or new studies can be contrasted. An example of the use of such expectations demonstrates that they can provide useful contextual information about the contrast among observations and our ability to identify their relationship with environmental drivers. [ABSTRACT FROM AUTHOR]

This document is a response to concerns raised about a previous publication on assessing and managing the ecological risk of microplastic pollution in the Great Lakes. The authors address the concerns raised, including errors in data rescaling and alignment, and the use of a species sensitivity distribution designed for marine systems in a freshwater system. They acknowledge the errors and provide corrections, and discuss the need for future research to develop more applicable risk assessment frameworks for the Great Lakes. The text also discusses the approach to separating species by "freshwater" and "marine" in risk assessment and suggests that other factors may be more meaningful. The authors address concerns about the lack of uncertainty estimates in the study and acknowledge that quantifying uncertainties would have strengthened the research. They conclude by emphasizing the importance of exploring different management approaches to address plastic pollution in the Great Lakes region, considering the complex jurisdictional landscape and the need for collaboration. The authors express gratitude to the microplastic research community for their contributions and engagement in improving risk assessment in the Great Lakes ecosystem. [Extracted from the article]

Organisms naturalized outside their native range can reveal new life history patterns in new environments. Here, we compare life history patterns of American shad, Alosa sapidissima, from five rivers along the U.S. Pacific coast (introduced range) with contemporary data from the Atlantic coast source populations. The Pacific coast fish grew slower, matured at a younger age, and were less often iteroparous than conspecifics from the Hudson River and Susquehanna River sources. Differences among the Pacific coast populations indicated that some combination of phenotypic plasticity and genetic adaptation has occurred since the transplants in the 1870s. Microchemical analysis of otoliths from returning adults demonstrated an immature, extended freshwater life history form, locally known as "mini-shad". These fish remain in the river for at least 1 year or enter salt water briefly and then return to fresh water for several months prior to subsequent seaward migration and return as adults. This and other forms of variation (extent of estuary use and size at sea water entry) expand the understanding of Alosine migration and life history diversity. [ABSTRACT FROM AUTHOR]

Walleye (Sander vitreus) are a sexually dimorphic freshwater piscivore that have long been studied using bioenergetics modeling, yet robust estimates of metabolic rates for use in those models have been lacking. Therefore, we quantified the effects of body mass, water temperature, and sex, on standard metabolic rate (SMR). We estimated SMR across temperatures ranging 0.5–24 °C using intermittent-flow respirometry for male (n = 54) and female (n = 53) walleye raised in hatchery conditions. We found a significant interaction between sex and temperature, whereby males had lower SMR below 16 °C, but increased such that SMR was ∼16% higher than females at 22 °C. The mass-scaling coefficient, b, was similar for both sexes at a value around 1. These estimates are the first to be generated using respirometry for adult walleye and differ slightly from those being used by previous bioenergetics models, which may have underestimated the energetic costs of SMR, and did not include sex-specific estimates for metabolism. [ABSTRACT FROM AUTHOR]

Current estimates of the threatened southern distinct population segment of the North American green sturgeon (Acipenser medirostris) combine a plot-sampling density estimator with Dual frequency IDentification SONar (DIDSON) and adaptive resolution imaging sonar (ARIS) sonar data. From 2020 to 2022, we annually collected images of all known green sturgeon aggregations and compared the established method to an N-mixture model using side-scan sonar images. We compared 18 different N-mixture model combinations and chose an overdispersed Poisson model that produced estimated abundances of 742, 1286, and 1208 for 2020–2022, respectively. These numbers are ∼2 times greater than the previous method and, if sustained, would fulfill a key criterion for green sturgeon recovery. N-mixture models are known to be sensitive to violations of assumptions, such as the highly dispersed data from our study that caused serious issues, and we recommend practitioners make judicious use of overdispersion and goodness-of-fit tests and be able to identify parameter confounding between detectability and abundance estimates. For our green sturgeon, we recommend simpler population estimates and to focus future energy on reducing variability in the data collection process. [ABSTRACT FROM AUTHOR]

Fish production integrates changes in biomass from growth, reproduction, and mortality, and is a useful indicator for fisheries management. However, calculation of fish production has been limited by the intensive requirements for data on abundance, biomass, age structure, and vital rates, and so it is uncommon to find estimates of fish production for wetlands. We developed an approach to directly estimate production that is suitable for data-limited systems: a continuous time model of production describing individual growth over short time intervals with continuous time models of abundance and biomass over longer timescales. We applied this model for 18 Great Lakes coastal wetlands (GLCWs) on Lake Ontario, including Big Island Wetland (BIW). In BIW, most species were dominated in abundance and biomass by younger cohorts and, as a result, these young, fast-growing individuals contributed disproportionately to fish production. In total, BIW produced 336.1 kg·ha·year of fish and the other 17 neighbouring ranged between 447.7 and 1119.9 kg·ha·year. These are some of the first estimates of fish production for GLCWs, highlighting their value for managing Great Lakes fisheries. [ABSTRACT FROM AUTHOR]

Changing ratios of stable carbon (δ13C) and nitrogen (δ15N) isotopes in consumer tissues reflect foraging patterns over time and can be used to inform studies on historically vulnerable populations. Northern fur seals (NFS; Callorhinus ursinus) at San Miguel Island (SMI), California, have been severely impacted by climate events such as El Niño and remain susceptible to future environmental disturbances, necessitating the need to further understand their foraging ecology. We analyzed sequential δ13C and δ15N values along single NFS whiskers sampled from five pups and five unrelated post-parturient females at SMI and reconstructed temporally aligned stable isotope profiles for each whisker. Pup profiles consistently showed increases in postnatal δ13C and δ15N values that likely stem from pup consumption of maternal milk and changes in maternal foraging locations after parturition. Adult female profiles indicated predominantly heterogeneous foraging strategies and minimal foraging outside the Southern California Bight. These findings provide initial characterizations of longitudinal, stable isotope-derived foraging data for NFS from SMI and offer insight into the inference of otariid foraging ecology with sequential δ13C and δ15N values. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)