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There are many syntheses on the role of animal behavior in understanding and mitigating conservation threats for wildlife. That body of work has inspired the development of a new discipline called conservation behavior. Yet, the majority of those synthetic papers focus on non-fish taxa such as birds and mammals. Many fish populations are subject to intensive exploitation and management and for decades researchers have used concepts and knowledge from animal behavior to support management and conservation actions. Dr. David L. G. Noakes is an influential ethologist who did much foundational work related to illustrating how behavior was relevant to the management and conservation of wild fish. We pay tribute to the late Dr. Noakes by summarizing the relevance of animal behavior to fisheries management and conservation. To do so, we first consider what behavior has revealed about how fish respond to key threats such as habitat alteration and loss, invasive species, climate change, pollution, and exploitation. We then consider how behavior has informed the application of common management interventions such as protected areas and spatial planning, stock enhancement, and restoration of habitat and connectivity. Our synthesis focuses on the totality of the field but includes reflections on the specific contributions of Dr. Noakes. Themes emerging from his approach include the value of fundamental research, management-scale experiments, and bridging behavior, physiology, and ecology. Animal behavior plays a key role in understanding and mitigating threats to wild fish populations and will become more important with the increasing pressures facing aquatic ecosystems. Fortunately, the toolbox for studying behavior is expanding, with technological and analytical advances revolutionizing our understanding of wild fish and generating new knowledge for fisheries managers and conservation practitioners.

The sea lamprey (Petromyzon marinus) is invasive in the Laurentian Great Lakes. Trapping in large rivers could suppress sea lamprey recruitment by removing migrating adults prior to spawning. Currently, the proportion of sea lamprey trapped (efficiency) is too low for control purposes, possibly because trapping is biased toward certain behavioural types. We tested if individual differences in time to enter a novel environment (risk-taking) and proportion of time moving (activity) under standardized laboratory conditions were correlated with time to encounter and enter a trap in the field. 638 sea lamprey were tagged, assessed for risk-taking and activity in sequential trials, and released in the river to be trapped. In the laboratory, individuals differed consistently in risk-taking and activity behaviours, and more active individuals entered a simulated trap sooner than less active individuals. In the field, however, the times to first trap encounter, and capture in a trap, were not correlated with risk-taking or activity. Our study provides a novel demonstration of how patterns from small-scale behavioural studies may not extend to management-scale applications.

Effective management of freshwater fish habitat is essential to supporting healthy aquatic ecosystems and sustainable fisheries. In Canada, recent changes to the Fisheries Act enhanced the protection of fish habitat, but application of those provisions relies on sound scientific evidence. We employed collaborative research prioritization methods to identify scientific research questions that, if addressed, would significantly advance the management of freshwater fish habitat in Canada. This list was generated by a diverse group of freshwater fish experts, including substantial contributions from practitioners who administer provisions of the Fisheries Act. The research questions generated in this study identify priority topics for future research, while highlighting issues that could be addressed with different funding models. As a result, this study should support evidence-based management of Canada’s aquatic resources by identifying scientific knowledge gaps faced by practitioners, and suggesting mechanisms to address them. Given the important contribution of Canadian freshwater systems to global ecosystem values, and the similar scientific challenges facing fish habitat managers in other jurisdictions, this study is likely to have broad applicability.

Abundance estimates can be crucial for managing species of economic concern. The accuracy of these estimates can depend on the methods used to track animals and to estimate abundance from tracking data. We tested experimentally if disparate estimates of trapping efficiency calculated for sea lamprey (Petromyzon marinus) in the St. Marys River near Sault Ste. Marie, Canada could be explained by effects related to the invasiveness and handling involved in tagging or the tag size used in the marking procedures. Trapping is used to gauge adult abundance, trapping efficiency, and success of a binational sea lamprey control program in the Laurentian Great Lakes, North America. Our experiment compared nightly catches of sea lamprey marked with external fin clips, surgically-implanted passive integrated transponder tags (PIT-only), and surgically-implanted PIT and acoustic tags (PIT+acoustic). We found no evidence that the probability of being trapped was affected by the added invasiveness and handling of internal tagging. Nightly recaptures of PIT-only tagged sea lamprey, relative to fin-clipped sea lamprey, were not different from expectations based on the numbers of individuals released from each treatment group. Conversely, there was evidence of effects related to tag size. Nightly recaptures of PIT+acoustic tagged sea lamprey, relative to PIT-only tagged sea lamprey, were lower than expected based on numbers of individuals released from each treatment group. Effects related to tag size partially explain the disparate estimates in trapping efficiency observed for sea lamprey.

Barrier removal is a recognized solution for reversing river fragmentation, but restoring connectivity can have consequences for both desirable and undesirable species, resulting in a connectivity conundrum. Selectively passing desirable taxa while restricting the dispersal of undesirable taxa (selective connectivity) would solve many aspects of the connectivity conundrum. Selective connectivity is a technical challenge of sorting an assortment of things. Multiattribute sorting systems exist in other fields, although none have yet been devised for freely moving organisms within a river. We describe an approach to selective fish passage that integrates ecology and biology with engineering designs modeled after material recycling processes that mirror the stages of fish passage: approach, entry, passage, and fate. A key feature of this concept is the integration of multiple sorting processes each targeting a specific attribute. Leveraging concepts from other sectors to improve river ecosystem function may yield fast, reliable solutions to the connectivity conundrum.

David Lloyd George Noakes (1942–2020) is best known for his insatiable curiosity, his quick wit and dry sense of humor, his scientific contributions to the field of animal behaviour, and his ability to form and maintain long-lasting connections. His research interests were vast but remained grounded in early life history, behaviour, social behaviour, the evolution of behaviour, behavioural genetics, and evolutionary ecology. David had a remarkable ability to establish and maintain strong connections within the international academic community. David was also internationally recognized for his numerous contributions as a scientific editor, promoting accessibility to the international community that he served. We memorialize David’s legacy in this tribute article, ensuring that his accomplishments and the momentous impact he had on the scientific community are not soon forgotten.

Currently, application of lampricides and installation of low-head barriers are the only proven means of sea lamprey (Petromyzon marinus) control in the Great Lakes. While sea lamprey canno...

In most lamprey genera, “paired” species exist in which the larvae are morphologically indistinguishable but adult feeding type differs. The lack of diagnostic genetic differences in many pairs has led to suggestions that they constitute a single gene pool with environmentally influenced feeding types. To investigate whether stream characteristics are correlated with feeding type in the parasitic silver lamprey Ichthyomyzon unicuspis and non-parasitic northern brook lamprey I. fossor, eight variables (pH, alkalinity, conductivity, discharge, total dissolved solids, and density of larval sea lamprey Petromyzon marinus, Ichthyomyzon spp., and total larval density) were compared among eight streams with only silver lamprey, 10 with only northern brook lamprey, and 13 with both species, using classification tree analysis. The most parsimonious model had a 24% misclassification rate, with silver lamprey tending to inhabit streams with higher sea lamprey larval density and northern brook lamprey tending to inhabit streams with higher Ichthyomyzon larval density. We then conducted a pilot study investigating phenotypic plasticity in a lab-based common garden experiment and an in situ transplant experiment. These studies encountered myriad difficulties and were unable to demonstrate plasticity, but did identify challenges associated with culturing Ichthyomyzon larvae. Development of effective rearing procedures for Ichthyomyzon lampreys is essential for any future similar studies.

Social anxieties about the war and about what it was doing to the country permeated America. What would happen when the war was over? The plays at the end of the war ask what kind of country the United States will be after the war is won, what form postwar democracy will take, and what the county's relationship with the rest of the world what will be. Taken together, the plays produced near and just after the end of the war spend little time celebrating the Allies' victory. Rather, they look at the challenges that returning servicemen will face in trying to reestablish family relationships and trying to heal from psychological wounds. They look at the difficulties families will face when their serviceman doesn't return home. They look at how those on the home front have had to remake their lives in ways that the returning serviceman will have trouble recognizing. They look at how old prejudices will create new social divisions as black and Jewish servicemen return home. They look at how selfish special interests, political naivete, and sheer love of power may undermine the democratic cause for which the nation had fought the war. While much of the country's popular culture was ringing victory bells, along Broadway, many playwrights were sounding alarms.

This chapter looks at the operations of popular culture during the war, the rise of socially conscious theater in the 1930s, which established the aesthetic and ideological contexts in which theater about the war was produced, the economics and audiences for Broadway theater, and the cultural place of theater in American life in the 1930s and 1940s. The theater of the 1930s was unusually politically conscious, primarily due to the Great Depression, which engendered heightened awareness of class divisions and the distribution of wealth. This social consciousness led to the rise of theater groups like the Theater Guild, the Group Theater, and the Federal Theater Project, which often expressed anti-Nazi or antifascist views.

The American theater was not ignorant of the developments brought on by World War II, and actively addressed and debated timely, controversial topics for the duration of the war, including neutrality and isolationism, racism and genocide, and heroism and battle fatigue. Productions such as Watch on the Rhine (1941), The Moon is Down (1942), Tomorrow the World (1943), and A Bell for Adano (1944) encouraged public discussion of the war's impact on daily life and raised critical questions about the conflict well before other forms of popular media. American drama of the 1940s is frequently overlooked, but the plays performed during this eventful decade provide a picture of the rich and complex experience of living in the United States during the war years. McLaughlin and Parry's work fills a significant gap in the history of theater and popular culture, showing that American society was more divided and less idealistic than the received histories of the WWII home front and the entertainment industry recognize.

Wartime America underwent rapid transformation; men, women, and children saw their social roles redefined; and economic and racial divisions grew deeper and sharper edged. Theater was the perfect medium to represent home-front tensions and anxieties as they were manifested on the local level: the congenital civilian thrust into the military life as in Strip for Action and This Is the Army; the family pressured by rapid and dynamic social transformations as in Three's a Family, A New Life, and Men to the Sea; couples pressured by the carpe-diem spirit of the wartime romance as in On the Town and Those Endearing Young Charms; adolescents, often tempted into juvenile delinquency with the freedom of looser rules and mores as in Janie and Pick-Up Girl; men and women balancing patriotism and selfishness, as in The Voice of the Turtle and the shocking Tomorrow the World.

A major factor that affected most Americans' experience of the war is that it was always elsewhere. One role of U.S. popular culture during the war was to bring home aspects of the war, including the heroism, the suffering, the occupation, and resistance that were occurring in Britain, Europe, Africa, the Soviet Union, Asia, and the Pacific. The most successful overseas plays, such as The Wookey, The Moon Is Down, The Eve of St. Mark, and Flare Path, emphasize the element of democracy, manifested in the right to criticize authority and the right to make one's own decisions, to contrast the Allies' way of fighting the war with the fascist enemy's. They also emphasize that the individual's decision to sacrifice, fight, and die is most genuine and thus most valuable when it is motivated by some kind of personal connection.

Associations between behaviors and the development of different life history tactics have been documented in several species of salmon, trout, and charr. While it is well known that such behaviors are heritable the genes and molecular pathways connected to these behaviors remain unknown. We used an RNA-seq approach to identify genes and molecular pathways differentially regulated in brain tissue between “shy” and “bold” brook trout (Salvelinus fontinalis). A small number of genes were differentially expressed between the behavioral types at several months after hatching and two years of age. Pathway analysis revealed that EIF2 signaling differed consistently between shy and bold individuals suggesting large-scale differences in protein synthesis between behavioral types in the brain. Additionally, the RNA-seq data were used to find polymorphisms within the brook trout genome and a GWAS approach was used to test for statistical associations between genetic variants and behavior type. One allele located in a transcription factor (TSHZ3) contained a protein-coding non-synonymous SNP suggesting that functional variation within TSHZ3 is connected to the development of different behaviors. These results suggest that the molecular basis of behavioral development is complex and due to the differential expression of many genes involved in a wide-range of different molecular pathways.

Delineating patterns of extant genetic diversity is crucial for understanding the evolutionary history of populations and how they can be conserved. Brook trout (Salvelinus fontinalis; n = 173) were sampled from 11 locations in Nipigon Bay, Lake Superior to evaluate genetic differentiation between migratory (coaster) and non-migratory (resident) individuals. Stable isotope data were used to classify the trophic ecology of individuals, rather than relying on size or capture location and timing to classify ecotypes. Genome-wide association analysis of 4676 single nucleotide polymorphism (SNP) markers was conducted to test if phenotypic and behavioral differences within and among populations of brook trout were linked to allelic variation in the genome. Population genetic structure was also evaluated to determine the source of migratory coasters based on multilocus genotypes from a subset of 906 SNP markers. Significant population genetic structure was revealed among the sampled tributaries, and the population genetic structure suggests that a single, larger stream in the study area, Cypress River, was the primary source of migratory brook trout in Nipigon Bay. There was little evidence of genetic differentiation between sympatric migrant and stream-resident brook trout; across the genome only 11 SNP loci ( Data statement Raw RADseq is deposited in the NCBI Genbank Sequence Read Archive (PRJNA486545). Biological metadata and processed genotypes are found in the Electronic Supplementary Material (ESM).

We evaluated statistical methods for estimating abundances of adult sea lamprey (Petromyzon marinus) migrating in Great Lakes tributaries. The sea lamprey is the target of a basin-wide, bi-national control program. Abundance estimates from mark-recapture data are used to evaluate program success and the efficiency of sea lamprey trapping. Recent tracking studies suggested the mark-recapture estimates of abundance could be biased. We compared four estimators of abundance using stratified (weekly) mark-recapture data for 19 years of trapping in the St. Marys River. Abundances from the pooled Petersen estimator were similar to abundances from the stratified Schaefer and stratified Petersen estimators, but substantially lower than abundances from a stratified Bayesian P-spline estimator. In simulations of virtual populations, pooled Petersen and Bayesian P-spline estimates were similar across a range of conditions where catchability differed between marked and unmarked lamprey and changed over the trapping season, with one exception. Abundances from the Bayesian P-spline estimator were strongly positively biased when catchability of marked lamprey increased over the season, while catchability of unmarked lamprey did not. Estimates from both estimators were negatively biased when lamprey displayed consistent individual differences in catchability and positively biased when a proportion of marked lamprey fell back. Discrepancies between mark-recapture and tracking studies cannot be reconciled by the choice of abundance estimator, but could be an outcome of bias due to individual differences in catchability. Sea lamprey managers could also switch from the stratified Schaefer to the pooled Petersen estimator to simplify field operations without losing accuracy and precision.

Disruption of movement patterns due to alterations in habitat connectivity is a pervasive effect of humans on animal populations. In many terrestrial and aquatic systems, there is increasing tension between the need to simultaneously allow passage of some species while blocking the passage of other species. We explore the ecological basis for selective fragmentation of riverine systems where the need to restrict movements of invasive species conflicts with the need to allow passage of species of commercial, recreational, or conservation concern. We develop a trait-based framework for selective fish passage based on understanding the types of movements displayed by fishes and the role of ecological filters in determining the spatial distributions of fishes. We then synthesize information on trait-based mechanisms involved with these filters to create a multidimensional niche space based on attributes such as physical capabilities, body morphology, sensory capabilities, behavior, and movement phenology. Following this, we review how these mechanisms have been applied to achieve selective fish passage across anthropogenic barriers. To date, trap-and-sort or capture-translocation efforts provide the best options for movement filters that are completely species selective, but these methods are hampered by the continual, high cost of manual sorting. Other less effective methods of selective passage risk collateral damage in the form of lower or higher than desired levels of passage. Fruitful areas for future work include using combinations of ecological and behavioral traits to passively segregate species; using taxon-specific chemical or auditory cues to direct unwanted species away from passageways and into physical or ecological traps while attracting desirable species to passageways; and developing automated sorting mechanisms based on fish recognition systems. The trait-based approach proposed for fish could serve as a template for selective fragmentation in other ecological systems.

Amphibious fishes moving over land between aquatic habitats likely encounter abrupt changes in a number of environmental conditions, including salinity. This study characterized the 1) spatial heterogeneity in salinity in the mangrove forest habitat of the self-fertilizing, amphibious mangrove rivulus (Kryptolebias marmoratus), 2) metabolic cost and behavioral response to acute exposure to novel salinity, and 3) repeatability of individual responses to acute changes in salinity. In mangrove habitats on Long Caye, Belize, salinity varied widely over short distances from 20.9–41.7‰ over a 90 cm distance. In the lab, fish were exposed to an acute change in salinity of Δ10, 20, or 30‰. Oxygen consumption significantly decreased in response to a 10‰ decrease in salinity and increased when salinity was elevated by 30‰. Activity levels significantly increased with an increase in salinity (Δ20 and 30‰). Individuals showed repeatable differences in both oxygen consumption rates and activity levels. Together, our d...

We tested if consistent individual differences (CIDs) in the behaviour of sea lamprey (Petromyzon marinus) from the Laurentian Great Lakes could influence their vulnerability to trapping. The sea lamprey is invasive in the Upper Laurentian Great Lakes and the target of a binational control program. Trapping could be used for control if trapping efficiency is unbiased and effective. Our test involved comparing the behaviour of sea lamprey collected in the field from a trap (n = 42) at a barrier and electrofished (n = 9) downstream of the barrier. We quantified each individual's latency to exit an enclosure (a measure of exploration), proportion of time spent moving (a measure of general activity), and change in activity in response to a putative predator cue (a measure of boldness). CIDs were detected for each behaviour measured (intraclass correlations: 0.3–0.5). CIDs in behaviour also differed between trapped individuals and those collected downstream using electrofishing, irrespective of size, sex, and maturity status. Trapped individuals decreased their activity in response to a putative predator cue, while individuals collected using electrofishing increased their activity in response to the cue. Trapped individuals also tended to spend a greater proportion of time moving than individuals sampled downstream of the trap. However, the two samples of lamprey did not differ significantly in time taken to exit an enclosure. The behavioural differences between sea lamprey sampled from a trap and those sampled downstream of the trap suggest that CIDs in behaviour can influence an individual's vulnerability to trapping.

Harvest can change phenotypic traits of populations through immediate demographic consequences, evolutionary responses to harvest selection, or developmental responses by individuals. This study investigated the plastic phenotypic effects of harvest on size and age at maturity in a commercially exploited freshwater fish. We tested an individual growth and life history plasticity model using lagged correlations incorporating how harvesting fish ages 2 and older influenced the abundance of juvenile fish, resource availability, individual growth rates, and carry-over responses in age and size at maturity. Our test used cohort data for Lake Erie yellow perch (Perca flavescens). Age and size at maturity fluctuated widely and rapidly across 23 cohorts between 1991 and 2013, suggesting phenotypic plasticity contributed strongly to maturation dynamics. The changes in maturity could not be explained by responses to harvest, as expected under the plasticity model. In Lake Erie, age and size at maturity in yellow perch appear to be responding to other drivers, such as harvest-induced dynamics of other fish stocks or ecosystem changes that are independent of harvest.

Rapid evolution of pest, pathogen, and wildlife populations can have undesirable effects, for example, when insects evolve resistance to pesticides or fishes evolve smaller body size in response to harvest. A destructive invasive species in the Laurentian Great Lakes, the sea lamprey (Petromyzon marinus) has been controlled with the pesticide 3-trifluoromethyl-4-nitrophenol (TFM) since the 1950s. We evaluated the likelihood of sea lamprey evolving resistance to TFM by (i) reviewing sea lamprey life history and control; (ii) identifying physiological and behavioural resistance strategies; (iii) estimating the strength of selection from TFM; (iv) assessing the timeline for evolution; and (v) analyzing historical toxicity data for evidence of resistance. The number of sea lamprey generations exposed to TFM was within the range observed for fish populations where rapid evolution has occurred. Mortality from TFM was estimated as 82%–90%, suggesting significant selective pressure. However, 57 years of toxicity data revealed no increase in lethal concentrations of TFM. Vigilance and the development of alternative controls are required to prevent this aquatic invasive species from evolving strategies to evade control.

Crucial to the management of invasive species is understanding space use and the environmental features affecting space use. Improved understanding of space use by invasive sea lamprey (Petromyzon marinus) could help researchers discern why trap success in large rivers is lower than needed for effective control. We tested whether manipulating discharge nightly could increase trap success at a hydroelectric generating station on the St. Marys River. We quantified numbers of acoustically tagged sea lampreys migrating up to, and their space use at, the hydroelectric generating station. In 2011 and 2012, 78% and 68%, respectively, of tagged sea lampreys reached the generating station. Sea lampreys were active along the face, but more likely to occur at the bottom and away from the traps near the surface, especially when discharge was high. Our findings suggest that a low probability of encountering traps was due to spatial (vertical) mismatch between space use by sea lamprey and trap locations and that increasing discharge did not alter space use in ways that increased trap encounter. Understanding space use by invasive species can help managers assess the efficacy of trapping and ways of improving trapping success.

The effects of drain maintenance on fish habitat and benthic macroinvertebrate assemblages (fish prey) were investigated for eight agricultural drains in southwestern Ontario, Canada. Our investigation employed a replicated Before-After-Control-Impact (BACI) design where each maintained section of a drain was paired with an unmaintained section downstream and an unmaintained section on a nearby reference drain of similar size and position in the watershed. Seven variables characterizing physical habitat features important to fishes and three variables characterizing the taxonomic abundance, densities, and relative densities of benthic macroinvertebrates were measured before drain maintenance and 10-12 times over 2 years following maintenance. Pulse responses were detected for three habitat variables quantifying vegetative cover: percent vegetation on the bank, percent in-stream vegetation, and percent cover. All three variables returned to pre-maintenance levels within two years of maintenance. No consistent changes were observed in the remaining habitat features or in the richness and densities of benthic invertebrate assemblages following drain maintenance. Our findings suggest that key features of fish habitat, structural properties and food availability, are resistant to drain maintenance.

A better understanding of how human activities affect biodiversity can be important for effective resource management. We tested how excavation (maintenance) of agricultural drains (ditches) altered fish assemblages. Uncertainty regarding the effects of drain maintenance on fish assemblages has been a source of tension between landowners, drain superintendents, and fishery managers. Fish assemblages in eight southwestern Ontario drains were sampled repeatedly from before to 2 years after drain maintenance using a replicated before–after, control–impact (BACI) design. Relative to reference sites, we found no evidence for short- or long-term decreases in the number of species and total abundance of fishes following drain maintenance, nor any consistent change in assemblage composition, despite clear changes in physical habitat. The fish assemblages in drains were resilient to drain maintenance and did not show changes expected to concern fishery managers. Our findings provide fishery managers with the information needed to manage drain maintenance more effectively under the Fish Protection Program of the Fisheries Act and to develop drain maintenance practices that balance the needs of agriculture with the protection of fish biodiversity.

We identified aspects of the trapping process that afforded opportunities for improving trap efficiency of invasive sea lamprey (Petromyzon marinus) in a Great Lake's tributary. Capturing a sea lamprey requires it to encounter the trap, enter, and be retained until removed. Probabilities of these events depend on the interplay between sea lamprey behavior, environmental conditions, and trap design. We first tested how strongly seasonal patterns in daily trap catches (a measure of trapping success) were related to nightly rates of trap encounter, entry, and retention (outcomes of sea lamprey behavior). We then tested the degree to which variation in rates of trap encounter, entry, and retention were related to environmental features that control agents can manipulate (attractant pheromone addition, discharge) and features agents cannot manipulate (water temperature, season), but could be used as indicators for when to increase trapping effort. Daily trap catch was most strongly associated with rate of encounter. Relative and absolute measures of predictive strength for environmental factors that managers could potentially manipulate were low, suggesting that opportunities to improve trapping success by manipulating factors that affect rates of encounter, entry, and retention are limited. According to results at this trap, more sea lamprey would be captured by increasing trapping effort early in the season when sea lamprey encounter rates with traps are high. The approach used in this study could be applied to trapping of other invasive or valued species.

The majority of large North American rivers are fragmented by dams that interrupt migrations of wide-ranging fishes like sturgeons. Reconnecting habitat is viewed as an important means of protecting sturgeon species in U.S. rivers because these species have lost between 5% and 60% of their historical ranges. Unfortunately, facilities designed to pass other fishes have rarely worked well for sturgeons. The most successful passage facilities were sized appropriately for sturgeons and accommodated bottom-oriented species. For upstream passage, facilities with large entrances, full-depth guidance systems, large lifts, or wide fishways without obstructions or tight turns worked well. However, facilitating upstream migration is only half the battle. Broader recovery for linked sturgeon populations requires safe “round-trip” passage involving multiple dams. The most successful downstream passage facilities included nature-like fishways, large canal bypasses, and bottom-draw sluice gates. We outline an adaptive a...

Invasive sea lampreys (Petromyzon marinus) in the Laurentian Great Lakes are the target of binational control. Trapping of adults could be used for control if trap success was higher. At a hydro-generating station on the St. Marys River, we tested whether the probability of trap entry is low (0.2–0.3) because (i) lampreys spend insufficient time near traps to find and enter the trap, (ii) high discharge at trap sites makes attractant flow from traps difficult to detect or trap openings difficult to reach, and (iii) conspecifics impede trap entry. Discharge at the site was manipulated nightly, and the behaviour of lampreys at trap openings was video-recorded. Odds of a lamprey reaching a trap opening and entering the trap were 3.4 and 1.6 times higher, respectively, with every second spent at a trap. The probability of reaching a trap was not lower on nights when discharge was high or when conspecifics were present at the trap opening. Improved trap entry will require manipulation of stimuli other than discharge that affect the time spent at traps.

Better knowledge of upstream migratory patterns of spawning Sea Lampreys Petromyzon marinus, an invasive species in the Great Lakes, is needed to improve trapping for population control and assessment. Although trapping of adult Sea Lampreys provides the basis for estimates of lake-wide abundance that are used to evaluate the Sea Lamprey control program, traps have only been operated at dams due to insufficient knowledge of Sea Lamprey behavior in unobstructed channels. Acoustic telemetry and radiotelemetry were used to obtain movement tracks for 23 Sea Lampreys in 2008 and 18 Sea Lampreys in 2009 at two locations in the Mississagi River, Ontario. Cabled hydrophone arrays provided two-dimensional geographic positions from acoustic transmitters at 3-s intervals; depth-encoded radio tag detections provided depths. Upstream movements occurred at dusk or during the night (2015–0318 hours). Sea Lampreys were closely associated with the river bottom and showed some preference to move near banks in shall...

There is mounting evidence that populations of brook trout ( Salvelinus fontinalis ) inhabiting bays and tributaries along the north shore of Lake Superior exhibit partial migration. In this system some fish originate in tributaries and move into the lake for much of the year, grow large and migrate back into tributaries to spawn, whilst other smaller fish reside in tributaries and grow slowly. This study determined whether the stream dwelling brook trout reach sexual maturity in the stream habitats, a criterion needed to distinguish partial migration from other forms of migration that could maintain divergent forms and life histories of brook trout. Maturational development was determined for fish collected in July and August. Sampling these populations during fall spawning was not permitted due to conservation concerns. Male and females sampled from tributaries displayed δ 13 C signatures and growth histories characteristic of stream residency. Assessment of maturational development suggested that 33% of females would have been expected to spawn in the fall of that year. Our findings demonstrate that a portion of fish residing in tributaries reach sexual maturity without adopting summer residency in the lake providing evidence for partial migration over other forms of migration. Improved understanding of the variation in migratory behaviour in these brook trout populations will contribute to their conservation and management in the face of lake-wide declines of the migrant fish.

Little is known about the movements of most stream fishes, so fisheries managers often rely on natural history data from the literature to make management decisions. Observations of over 15 000 individuals from 37 species across 3 years were used to evaluate four aspects of the reliability of literature data for predicting the movement behaviour of stream fishes: (i) water temperature when fish enter streams; (ii) reasons for moving into the streams; (iii) stream residence times of migrants; and (iv) relative use of lake and stream habitats. Comparisons of our data for arrival times in the streams, water temperature at arrival, and time spent in the streams were highly correlated with literature data, whereas relative use of the lake was not. Further, our detailed data revealed two novel findings: (1) in many species juveniles were also moving into streams, even in those species where adults were clearly spawning in the streams; and (2) adult-sized individuals were moving into streams for nonreproductive purposes. Our results suggest that fishery managers can confidently use natural history information to gain general insights into the movement ecology of fishes, but should also recognize that this information remains incomplete in important ways.

Recently emerged brook charr (Salvelinus fontinalis) foraging in still-water pools along the sides of streams tend to be either sedentary, feeding from the lower portion of the water column (a sit-and-wait tactic), or very active, feeding from the upper portion of the water column (an active search tactic). We tested whether the individual differences in foraging behavior were associated with baseline concentrations and responses of cortisol, a steroid hormone linked to personality differences in a variety of animals including fishes. We quantified the proportion of time spent on moving by focal charr in the field and then capturing them. Captured individuals were either (i) sacrificed immediately to quantify baseline cortisol concentrations, (ii) held in an unfamiliar field environment for 15 min and then sacrificed to quantify cortisol concentrations in response to handling and holding in a novel field environment, or (iii) held in an unfamiliar field environment with a white Plexiglas base (stressor) for 15 min to quantify cortisol concentrations in response to a novel object. Eleven statistical models relating cortisol concentrations to the proportion of time individuals spent on moving while searching for prey were compared using multi-model inferencing. Cortisol concentrations were higher for charr that spent a lower proportion of time on moving in the field than for charr that spent a higher proportion of time on moving. For a given proportion of time spent on moving, mean cortisol concentrations between baseline and experimental treatments, our measure of cortisol response, did not differ markedly. Our findings suggest that the foraging tactics displayed by wild brook charr in the field could reflect differences in how individuals perceive their environment.

Scientific advances are needed to contend with invasive species. Trapping is often used for control or assessment, and understanding the invasive species’ behaviour is important for trapping success. A framework linking behaviour to trapping success and management responses was used to test hypotheses for the low trapping success of invasive sea lamprey (Petromyzon marinus) in the St. Marys River connecting Lakes Superior and Huron. Behaviour of sea lamprey approaching and at traps was quantified using external and internal tags and video. Multistate Markov models identified phenotypic and environmental factors influencing trapping success. Low trapping success for invasive sea lamprey in the St. Marys River is due to individuals not encountering traps, not entering upon encounter, not remaining at the trap, and not returning upon departure. All trapped lamprey were retained. Encounter with, and entrance into, traps varied with sea lamprey class, release date, and time of day, but not body length or river discharge. The conceptual and analytical methods applied here could be used to understand and improve trapping success for other invasive animals.