Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 12, Page iii-iv, December 2020.

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Intra-annual reproductive investments may not be predictive of male reproductive success because of the effects of intra- and intersexual interactions on sperm depletion. For long-lived iteroparous fish species such as lake sturgeon (Acipenser fulvescens), reproductive effort may affect lifetime reproductive success. Radio frequency

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Alternative reproductive tactics are widespread in fishes. In Pacific salmon, males either become a competitive hooknose, or a sneaker jack, which is undesirable in aquaculture when overabundant. Juveniles often experience accelerated growth prior to becoming jacks, potentially caused by increased competitiveness. We tested the behaviour

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. The southern king crab (Lithodes santolla) supports one of the most important fisheries in southern South America. Lecithotrophic larvae hatch over an extended period, in which brooding females can be fished, but must be discarded due to regulations. Larval mortality by female fishing was evaluated. Samples of newly hatched zoeae I

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Information on biological status is essential for designing, implementing, and evaluating management strategies and recovery plans for threatened or exploited species. However, the data required to quantify status are often limited, and it is important to understand how assessments of status may be biased by assumptions in data analysis

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Management of Atlantic cod (Gadus morhua) off southern Newfoundland (Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps) entails allocated quotas and restrictions on fishing during late winter and springtime to protect presumed spawning aggregations. We present data collected from research trawls and handlines (1995–2014)

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Fraser River Pacific salmon have declined in recent decades, possibly from parasitism by sea lice (Caligus clemensi and Lepeophtheirus salmonis). We describe the abundance of both louse species infesting co-migrating juvenile pink (Oncorhynchus gorbuscha), chum (Oncorhynchus keta), and sockeye (Oncorhynchus nerka) salmon over 5 years

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Although telemetry is commonly used to study fishes, researchers rarely design experiments that facilitate in situ quantification of tagging-related impacts to survival. We experimentally applied high (mean burden = 9.6%) and low (2.6%) acoustic tag burdens and gill clip biopsies to migrating juvenile sockeye salmon (Oncorhynchus nerka)

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Most previous systems for quantifying ventilatory flow in fish involve prior anesthesia and difficult surgery to sew or glue membranes to the animal, which are undoubtedly stressful. By modification of the original “van Dam box” design and incorporation of an electromagnetic blood flow probe, we have developed a less invasive system

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. The number of effective breeders (Nb) has been touted as a means to monitor freshwater fishes, but the realized application of Nb has been limited. Using genetic monitoring data for two Arctic grayling (Thymallus arcticus) populations of conservation concern, we describe temporal trends in genetic variation and Nb, determine how sampling

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Fish recruitment is complex and difficult to predict. Data-driven approaches show promise for predicting recruitment and understanding its drivers. We used a random forest model to infer relationships between year-class strength and 17 variables describing potential recruitment drivers across 30+ years of walleye (Sander vitreus) data

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. We develop a mechanistically motivated von Bertalanffy growth model to estimate growth rate and its predictors from spatial–temporal data and compare this model’s performance with a suite of commonly used mixed-effects growth models. We test these models with simulated data and then apply them to test whether concerns that high density

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Migrating adult Pacific salmon (Oncorhynchus spp.) are sensitive to warm water (>18 °C), with a range of consequences from decreased spawning success to early mortality. We examined the proportion of Yukon River Chinook salmon (O. tshawytscha) exhibiting evidence of heat stress to assess the potential that high temperatures contribute

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Climate change is altering hydrologic regimes, with implications for lake water levels. While lakes within lake districts experience the same climate, lakes may exhibit differential climate vulnerability regarding water level response to drought. We took advantage of a recent drought (∼2005–2010) and estimated changes in lake area

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Age composition is defined as the proportion of a fish population belonging to each age class and is an informative input to stock assessment models. Variations in somatic growth rates may lead to larger errors in age composition estimates. To reduce this source of error, we compared the performance of four methods for estimating age

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. The River Continuum Concept (RCC) is a milestone in stream ecology because of its comprehensive evaluation of the structure and function of lotic ecosystems. Linking stream physical and geomorphological attributes with patterns in biodiversity, functional traits, and metabolism dynamics, this theory describes downstream gradients in

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Numerous laboratory and field studies have found that female Pacific salmon have higher mortality than males during their once-in-a-lifetime upriver spawning migration. However, the proximate cause(s) of this increased mortality are poorly understood. This study exposed sockeye salmon (Oncorhynchus nerka) to a mild capture and tagging

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Many animals undertaking long-distance migrations use Earth’s magnetic field as a “map” to assess their position for orientation. This phenomenon been particularly well-studied in salmonids using “magnetic displacement” experiments, in which animals are presented with magnetic field conditions that are characteristic of other geographic

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Introduced Pacific salmon (Oncorhynchus spp.) deliver novel, pulsed resource subsidies to Great Lakes streams. We explored interactions between native brook trout (Salvelinus fontinalis) and non-native brown trout (Salmo trutta) in the context of this resource pulse. Diets surveyed before and during salmon spawning showed that, regardless

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. Behaviour that is adaptive in captivity may be maladaptive in the wild and compromise postrelease survival of hatchery fish. The understanding of behavioural variation displayed immediately after release could help to improve hatchery protocols and development of behavioural tests for assessing the fitness of fish reared for releases

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. In streams where water availability is limited, conservative flow ranges are often adopted by water managers to ensure that streamflow is available to meet the ecological requirements of aquatic organisms. However, a variety of natural and anthropogenic disturbances can influence stream channel morphology and in-stream wood characteristics

Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print. During stock assessment, fishery-dependent observations are often used to develop indices of abundance or biomass from catch per unit of effort (CPUE) and contribute catch at size or age information. However, fisher behavior, rather than scientific sampling protocols, determines the spatial and temporal locations of fishery-dependent

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1612-1624, October 2020. The Arctic nearshore surrounding Point Barrow, Alaska, is a dynamic system with complex oceanographic and meteorological processes that drive community composition to change rapidly in space and time. Nearshore fish and zooplankton communities were sampled in the summers of 2013–2015. Spatial, temporal

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Two primary goals in fisheries research are to (i) understand how habitat and environmental conditions influence the distribution of fishes across the landscape and (ii) make predictions about how fish communities will respond to environmental and anthropogenic change. In inland, freshwater ecosystems, quantitative approaches traditionally

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Analysis of growth increments in the hard parts of animals (e.g., fish otoliths) can be used to assess how organisms respond to variability in environmental conditions. In this study, mixed-effects models were applied to otolith data simulated for two hypothetical fish populations with assumed biological parameters and known growth

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. The ability of passive integrated transponder (PIT) tag data to improve demographic parameter estimates has led to the rapid advancement of PIT tag systems. However, ghost tags create uncertainty about detected tag status (i.e., live fish or ghost tag) when using mobile interrogation systems. We developed a method to differentiate

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Owing to declines in salmonid populations, in-stream restoration structures have been used for over 80 years to increase abundance of fish. However, the relative effectiveness of these structures remains unclear for some species or regions, partly due to contrasting conclusions from two previous meta-analyses. To update and reconcile

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1292-1301, August 2020. While conservation and fisheries management are often concerned with changes in population abundance and distribution, shifts in population age–size structure are commonly observed in response to human and environmental stressors. Chinook salmon (Oncorhynchus tshawytscha) have experienced widespread

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1275-1280, August 2020. We present a visual and tabular representation of fisheries stock assessment model outputs to rapidly examine and effectively communicate sensitivity analysis results from numerous alternative model comparisons. This approach uses multiple output metrics to identify which alternative stock assessment

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1741-1748, October 2020. There is an increasing concern about the potential for size-selective harvest to impair population persistence. Yet little is known about the relative contribution of the evolutionary (shifts in life history) and demographic effects (decreased population density and size truncation) of harvesting

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1733-1740, October 2020. Direct age determination of crustaceans has remained a long-standing challenge because all calcified structures are shed with each molt. Cuticle bands in the ossicles of the gastric mill have shown promise as age indicators. We validated the one-to-one relationship between known age and number of

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1721-1732, October 2020. With advances in molecular genetics, it is becoming increasingly feasible to conduct genetic stock identification (GSI) to inform management actions that occur within a fishing season. While applications of in-season GSI are becoming widespread, such programs seldom integrate data from previous years

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1711-1720, October 2020. The size selectivity of four codends were compared in the Gulf of St. Lawrence, Canada, redfish fishery (Sebastes mentella), including the regulated diamond mesh codend with a mesh opening of 90 mm (T0) and three experimental codends of different mesh openings (90, 100, 110 mm) in which the netting

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1700-1710, October 2020. Stock assessments for a majority of the world’s fisheries often do not explicitly consider the effects of environmental conditions on target species, which can raise model uncertainty and potentially reduce forecasting quality. Model-based abundance indices were developed using a delta generalized

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1688-1699, October 2020. Fisheries management usually does not explicitly account for spatial variation in life history traits within populations. However, for some stocks this spatial variation may be substantial. We develop a spatiotemporal generalized linear model and fit the model to a long time series of maturation data

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1666-1677, October 2020. Although white sharks (Carcharodon carcharias) have been considered rare in Atlantic Canada waters, recent sighting records indicate a potentially increasing presence. We combine historical to present sighting data with satellite telemetry tracks of large juvenile and adult white sharks tagged in

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1678-1687, October 2020. Depth gradients in lakes are often key drivers of population divergence and speciation in fishes. New Zealand has many deep lakes but no known profundal specialist fishes or cases of intralacustrine speciation. We sampled a native benthic fish, the common bully (Gobiomorphus cotidianus), from 5 to

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1659-1665, October 2020. Understanding how different drivers shape relationships between abundance and body mass (size spectra) is important for understanding trophic and competitive interactions in food webs and for predicting the effects of human pressures. Here, we sample seabed communities from small polychaetes (<0.001

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1638-1658, October 2020. An age-structured, spatial survey-based assessment model (SSURBA) is developed and applied to the Grand Banks stock (NAFO Divisions 3LNO) of American plaice (Hippoglossoides platessoides) in Newfoundland and Labrador. The state-space model is fit to annual spatial (i.e., three divisions) stock size-at-age

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1625-1637, October 2020. As the global human population grows, it remains a top priority for communities, managers, policymakers, and stakeholders to maintain healthy, sustainable, and productive fisheries under continued global change. Here we used a dataset consisting of fish and lake characteristics for 536 lakes across

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 10, Page 1601-1611, October 2020. Multiple restoration actions have been implemented in response to declining salmon populations. Among these is the addition of salmon carcasses or artificial nutrients to mimic marine-derived nutrients historically provided by large spawning runs of salmon. A key assumption in this approach is that

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Conservation and management measures for large mobile sharks are more effective when information on migratory patterns and environmental cues are known. In the absence of long-term monitoring data or tracking programs, available information is based on occasional catch or sighting records from a variety of sources, usually constrained

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Human activities have the potential to accelerate population-level decline by contributing to climate warming and decreasing the capacity of species to survive warming temperatures. Here we build a predictive model to test interactions between river warming and catch and release mortality in recreational fisheries for Atlantic salmon

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Direct DNA sequencing is powering a revolution in the application of genetics to resource management, with parentage-based tagging (PBT) increasingly applied to salmon fisheries and hatchery brood stock management and assessment. Genetic stock identification (GSI) and PBT were applied to assessment of 2018 coho salmon (Oncorhynchus

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Scientists across many fields are faced with the challenge of synthesizing and communicating information from large and complex data sets. The field of stock assessment is no exception as the volume and variety of the data has grown alongside the computational methods used to integrate them. While this growth in data and model complexity

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Fish face many anthropogenic stressors. Authorities in marine, estuarine, and freshwater realms often share interdependent fisheries management goals, but address singular stressors independently. Here, we present a case study suggesting that coordinating stressor relief across management realms may synergize conservation efforts

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Recovery of imperiled fishes can be achieved through suppression of invasives, but outcomes may vary with environmental conditions. We studied the response of imperiled desert fishes to an invasive brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) suppression program in a Colorado River tributary, with natural flow and

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Construction of artificial channels to divert water is common in a variety of natural resource development projects; however, the length of time required for these stream channels to become productive fish habitat remains an understudied aspect. The creation of a bedrock channel (∼150 m) to drain a third-order boreal lake and its

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Migration rates, delay, timing, and success of acoustic-tagged Atlantic salmon (Salmo salar) presmolts (n = 120) and smolts (n = 57) are reported as they moved through the large Mactaquac Generating Station (MGS) reservoir and subsequently the lower Saint John River (SJR). The potential relationship between fish movements and the

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1421-1432, August 2020. Monitoring distributional shifts in Arctic and subarctic fish species as environmental conditions change can be difficult due to sparse or infrequent surveys. Pacific halibut (Hippoglossus stenolepis) are found as far north as the Bering Strait, and future changes in sea temperatures and prey distribution

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1409-1420, August 2020. The British Columbia longline fishery for Pacific halibut (Hippoglossus stenolepis) has experienced important recent management changes, including the introduction of comprehensive electronic catch monitoring on all vessels; an integrated transferable quota system; a reduction in Pacific halibut quotas;

Canadian Journal of Fisheries and Aquatic Sciences, e-First Articles. Understanding factors mediating hybridization between native and invasive species is crucial for conservation. We assessed the spatial distribution of hybridization between invasive rainbow trout (Oncorhynchus mykiss) and native Yellowstone cutthroat trout (Oncorhynchus clarkii bouveri) in the Lamar River of Yellowstone National

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1393-1408, August 2020. Tributary junctions are regarded as ecologically important due to unique habitat present; however, there is limited understanding of the drivers of habitat attributes at these locations. Using six sites across two mainstem rivers, we tested whether tributary size relative to main stem governs the strength

Eutrophication increases hypoxia in lakes and reservoirs, causing deleterious effects on biological communities. Quantitative models would help managers develop effective strategies to address hypoxia issues, but most existing models are limited in their applicability to lakes with temporally resolved dissolved oxygen data. We describe a hierarchical Bayesian model that predicts dissolved oxygen in

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1379-1392, August 2020. Invasive grass carp (Ctenopharyngodon idella) are known to spawn in the Sandusky River, Ohio, USA, within the Great Lakes Basin, and are threatening to expand throughout the Great Lakes. Successful spawning is thought to require that eggs remain in suspension until hatching, which depends on river hydrodynamics

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1366-1378, August 2020. Walleye (Sander vitreus) is a popular sportfish threatened by overexploitation, habitat destruction, and loss of genetic integrity due to non-native walleye stocking. Previous studies have identified a genetically distinct lineage of walleye in the Mobile River Basin, but further work is needed to assess

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1359-1365, August 2020. Niche divergence resulting from coevolution is commonly believed to favour coexistence among competing species; however, recent investigations have demonstrated that an unexpected niche convergence can occur when native and non-native species coexist. Yet, our understanding of the ontogenetic characteristics

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1348-1358, August 2020. Food-web investigations inform management strategies by exposing potential interactions between native and nonnative species and anticipating likely outcomes associated with species removal efforts. We leveraged a natural gradient of compositional turnover from native-only to nonnative-only fish assemblages

Canadian Journal of Fisheries and Aquatic Sciences, Volume 77, Issue 8, Page 1332-1347, August 2020. Northern shrimp (Pandalus borealis) represents one of the most important fisheries in the Northwest Atlantic Ocean, but few studies have considered connectivity among different management units (i.e., stocks). Using a biophysical model, we investigated potential larval dispersal among North Atlantic