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Growing interest in apps to collect recreational-fisheries data requires that relationships between self-reported data and other fisheries data are evaluated, and that potential biases are assessed. This study compared results from a mobile-phone application and website for anglers (MyCatch) to results from three types of fisheries surveys--1 provincial-level mail survey, 2 creel, and 17 gillnet surveys. Results suggest that an app and website can (i) recruit users that have a broad spatial distribution that is similar to conventional surveys, (ii) generate data that capture regional fishing patterns (2218 trips on 289 lakes and 90 streams or rivers), and (iii) provide catch rate estimates that are similar to those from other fisheries-dependent surveys. Some potential biases in app users (e.g., urban bias) and in the relative composition of species caught provincially were identified. The app was not a suitable tool for estimating fish abundance and relative community composition. Our study demonstrates how apps can or cannot provide a complementary data-collection tool for recreational-fisheries monitoring, but further research is needed to determine the applicability of our findings to other fisheries contexts. Etant donne l'interet croissant pour les applications de cueillette de donnees sur les peches sportives, il est necessaire d'evaluer les relations entre les donnees autodeclarees et d'autres donnees sur les peches, ainsi que les biais potentiels. L'etude compare les resultats d'une application pour telephone mobile et d'un site web pour pecheurs sportifs (MyCatch) aux resultats de trois types d'enquetes sur les peches--une enquete provinciale par la poste, deux enquetes par interrogation de pecheurs et 17 releves au filet maillant. Les resultats donnent a penser qu'une appli et un site web peut (i) recruter des utilisateurs presentant une repartition spatiale aussi vaste que celle d'enquetes traditionnelles, (ii) produire des donnees qui capturent les motifs regionaux de peche (2 218 excursions sur 289 lacs et 90 cours d'eau ou rivieres) et (iii) fournir des estimations des taux de prises qui sont semblables a celles obtenues d'autres enquetes dependantes de la peche. Certains biais potentiels chez les utilisateurs de l'appli (p. ex. biais urbain) et dans la composition relative des especes capturees a l'echelle provinciale sont releves. L'appli ne s'avere pas etre un bon outil pour estimer l'abondance de poissons et la composition relative de la communaute. L'etude demontre comment des applis peuvent ou non constituer des outils de collecte de donnees complementaires pour la surveillance des peches sportives, mais d'autres travaux de recherche sont necessaires pour etablir l'applicabilite de nos resultats a d'autres contextes de peche. [Traduit par la Redaction], Introduction Recreational fishers are one of the dominant users of inland fisheries resources in industrialized nations (Arlinghaus et al. 2015, 2019), important users of marine resources (Coleman et al. 2004; [...]

Complexity of addressing cumulative effects that vary in space and time, especially for species occupying large ranges, makes conservation and recovery of populations difficult. In Alberta, declines of all three native stream trout species led to them being listed as species at risk. We developed a novel, semi‐quantitative cumulative effects modelling process to quantify threats using stressor‐response curves with a single common response scale, wherein inputs were determined for each population, and outputs were used to create population‐specific recovery action hypotheses to inform management. Using a case study of bull trout recovery in Rocky Creek, Alberta, we tested these hypotheses using a before–after control‐impacted design. Recovery actions positively affected bull trout, and the modelling approach provided insight into threats (sedimentation and angling effort) that most likely limited the population. [ABSTRACT FROM AUTHOR]

Using a bioeconomic model, we systematically investigated how hooking mortality and regulatory noncompliance influenced management outcomes across a range of freshwater fish species exploited by diverse angler populations. The model integrated an empirically based submodel describing the behaviour of three angler types with an age-structured fish population submodel calibrated to five life-history types (LHTs). Increased hooking mortality generally undermined regulation effectiveness, decreased socially optimal input (license numbers) and output regulations (minimum-size limits), and eroded the social welfare anglers derived from the fishery. However, the results strongly varied with LHT and angler type. Noncompliance had an isolated effect, primarily affecting fish species with low compensatory reserves when hooking mortality was low. However, in the absence of regulatory constraints on effort, noncompliance facilitated recruitment overfishing and increased the minimum-size limit required to avoid it. Despite added mortality from hooking and noncompliance, the strong dependence of angler utility on catch rates usually meant socially optimal management safeguarded biological sustainability. Yet, ignoring hooking mortality and noncompliance when predicting optimal regulations often led to population collapse. To conclude, models designed to derive recommendations for recreational fisheries management must consider both hooking mortality and noncompliance. Otherwise, dissatisfied anglers or biologically overfished stocks are possible. En utilisant un modele bioeconomique, nous avons systematiquement examine l'incidence de la mortalite par hamecon et de la non-conformite aux reglements sur les resultats de gestion pour un vaste eventail d'especes de poissons d'eau douce exploitees par differentes populations de pecheurs sportifs. Le modele integre un sous-modele a fondement empirique qui decrit le comportement de trois types de pecheurs et un sous--modele de population de poissons structuree par age calibre en selon cinq types de cycle biologique (TCB). En general, l'augmentation de la mortalite par hamecon reduit l'efficacite de la reglementation, les reglements sur les entrees (nombre de permis) et sorties (limites de taille minimum) socialement optimales et le bien-etre social que confere la peche aux pecheurs. Les resultats varient toutefois fortement selon le TCB et le type de pecheur sportif. La non-conformite a un effet isole, principalement sur les especes de poissons presentant de faibles reserves compensatoires quand la mortalite par hamecon est faible. En l'absence de contrainte reglementaire concernant l'effort, la non-conformite favorise toutefois la surpeche du potentiel reproducteur et fait augmenter la limite de taille minimum necessaire pour eviter cette surpeche. Malgre une mortalite supplementaire par hamecon et du fait de la non-conformite, la forte dependance de l'utilite pour les pecheurs sur les taux de prises signifie generalement qu'une gestion socialement optimale preserve la durabilite biologique. En outre, le fait de ne pas tenir compte de la mortalite par hamecon et de la non- conformite dans les previsions concernant la reglementation optimale mene souvent a l'effondrement de populations. En conclusion, des modeles concus pour elaborer des recommandations pour la gestion des peches sportives doivent prendre en consideration tant la mortalite par hamecon que la non-conformite, a defaut de quoi des pecheurs non satisfaits et la surpeche biologique des stocks sont possibles. [Traduit par la Redaction], Introduction Recreational fisheries constitute the dominant user of inland fish stocks and are also becoming important in many coastal fisheries across the developed world (FAO 2012). Recreational fishing pressure has [...]

: In many areas of the world, recreational fisheries are not managed sustainably. This might be related to the omission or oversimplification of angler behaviour and angler heterogeneity in fisheries-management models. We present an integrated bioeconomic modelling approach to examine how differing assumptions about angler behaviour, angler preferences, and composition of the angler population altered predictions about optimal recreational-fisheries management, where optimal regulations were determined by maximizing aggregated angler utility. We report four main results derived for a prototypical northern pike (Esox lucius) fishery. First, accounting for dynamic angler behaviour changed predictions about optimal angling regulations. Second, optimal input and output regulations varied substantially among different angler types. Third, the composition of the angler population in terms of angler types was important for determining optimal regulations. Fourth, the welfare measure used to quantify aggregated utility altered the predicted optimal regulations, highlighting the importance of choosing welfare measures that closely reflect management objectives. A further key finding was that socially optimal angling regulations resulted in biological sustainability of the fish population. Managers can use the novel integrated modelling framework introduced here to account, quantitatively and transparently, for the diversity and complexity of angler behaviour when determining regulations that maximize social welfare and ensure biological sustainability. Resume: Dans plusieurs regions du monde, les peches sportives ne sont pas gerees de maniere durable. Cela peut etre du a l'omission ou a la sursimplification du comportement et de l'heterogeneite des pecheurs dans les modeles de gestion de la peche. Nous presentons une methodologie de modelisation bioeconomique integree pour examiner comment diverses presuppositions concernant le comportement des pecheurs, les preferences des pecheurs et la composition de la population de pecheurs alterent les predictions concernant la gestion optimale des peches sportives, lorsque les reglementations optimales sont determinees en maximisant l'utilite globale pour les pecheurs. Nous presentons quatre resultats principaux issus d'une peche prototypique au grand brochet (Esox lucius). Premierement, tenir compte du comportement dynamique des pe-cheurs modifie les predictions sur les reglementations optimales de la peche. Deuxiemement, les regulations optimales des apports et des sorties varient considerablement en fonction des divers types de pecheurs. Troisiemement, la composition de la population de pecheurs en ce qui a trait au types de pecheurs est importante pour determiner les reglementations optimales. Quatriemement, la mesure de bien public utilisee pour determiner l'utilite globale change les reglementations optimales predites, ce qui souligne l'importance de choisir des mesures de bien public qui refletent bien les objectifs de gestion. Une autre decouverte importante est que des reglementations de peche optimales du point de vue social resultent en des populations de poissons durables du point vue biologique. Les gestionnaires peuvent utiliser le cadre inedit de modelisation integre que nous presentons ici pour tenir compte de facon quantitative et transparente de la diversite et de la complexite des comportements des pecheurs lorsqu'ils mettent en place des reglementations qui maximisent le bien public et assurent la durabilite biologique. [Traduit par la Redaction], Introduction Recreational anglers are the dominant users of most freshwater and some coastal fish stocks in industrialized countries (Arlinghaus and Cooke 2009). Accordingly, managers are faced with the challenge of [...]

Abstract: An exploited bull trout, Salvelinus confluentus, population experienced a 28-fold increase in adult density during a 10-year period from a minimum of 60 individuals. This demonstrates the extent to [...]

Ref.: Can. J. Fish. Aquat. Sci. 67: 1507-1531 (2010). In Table 1 in the printed and online versions of the article, there are typesetting errors in eqs. 2a, 2c, and [...]

Managing fisheries using length-based harvest regulations is common, but such policies often create trade-offs among conservation (e.g. maintaining natural age-structure or spawning stock biomass) and fishery objectives (e.g. maximizing yield or harvest numbers). By focusing harvest on the larger (older) fish, minimum-length limits are thought to maximize biomass yield, but at the potential cost of severe age and size truncation at high fishing mortality. Harvest-slot-length limits (harvest slots) restrict harvest to intermediate lengths (ages), which may contribute to maintaining high harvest numbers and a more natural age-structure. However, an evaluation of minimum-length limits vs. harvest slots for jointly meeting fisheries and conservation objectives across a range of fish life-history strategies is currently lacking. We present a general age- and size-structured population model calibrated to several recreationally important fish species. Harvest slots and minimum-length limits were both effective at compromising between yield, numbers harvested and catch of trophy fish while conserving reproductive biomass. However, harvest slots consistently produced greater numbers of fish harvested and greater catches of trophy fish while conserving reproductive biomass and a more natural population age-structure. Additionally, harvest slots resulted in less waste in the presence of hooking mortality. Our results held across a range of exploitation rates, life-history strategies and fisheries objectives. Overall, we found harvest slots to represent a valuable option to meet both conservation and recreational fisheries objectives. Given the ubiquitous benefits of harvest slots across all life histories modelled, rethinking the widespread use of minimum-length limits is warranted. [ABSTRACT FROM AUTHOR]

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries ( EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries-induced evolution ( FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life-history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment ( Evo IA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. Evo IA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries. [ABSTRACT FROM AUTHOR]

To predict recreational-fishing impacts on freshwater fish species, it is important to understand the interplay between fish populations, anglers and management actions. We use an integrated bioeconomic model to study the importance of fish life-history type ( LHT) for determining (i) vulnerability to over-exploitation by diverse angler types (generic, consumptive and trophy anglers), who respond dynamically to fishing-quality changes; (ii) regulations [i.e., minimum-size limits ( MSLs) and licence densities] that maximize the social welfare of angler populations; and (iii) biological and social conditions resulting under such socially optimal regulations. We examine five prototypical freshwater species: European perch ( Perca fluviatilis), brown trout ( Salmo trutta), pikeperch ( Sander lucioperca), pike ( Esox lucius) and bull trout ( Salvelinus confluentus). We find that LHT is important for determining the vulnerability of fish populations to overfishing, with pike, pikeperch, and bull trout being more vulnerable than perch and brown trout. Angler type influences the magnitude of fishing impacts, because of differences in fishing practices and angler-type-specific effects of LHT on angling effort. Our results indicate that angler types are systematically attracted to particular LHTs. Socially optimal minimum-size limits generally increase with LHT vulnerability, whereas optimal licence densities are similar across LHTs. Yet, both regulations vary among angler types. Despite this variation, we find that biological sustainability occurs under socially optimal regulations, with one exception. Our results highlight the importance of jointly considering fish diversity, angler diversity and regulations when predicting sustainable management strategies for recreational fisheries. Failure to do so could result in socially suboptimal management and/or fishery collapse. [ABSTRACT FROM AUTHOR]