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Successful integrated management of the invasive predatory sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes of North America is owed largely to the long history of beneficial use of two lampricides: 3-trifluoromethyl-4nitrophenol (TFM) and 2',5-dichloro-4'-nitrosalicylanilide (niclosamide). Ensuring continued successful sea lamprey control necessitates consideration of possible next-generation lampricides to supplement or replace current lampricides. This review identifies fifteen hallmarks of success for current lampricides to be used as design criteria in a search for nextgeneration lampricides. A three-stage research approach is outlined. Targeted research using omics, computer modelling, and high-throughput technology to define molecular mechanisms and high probability molecular targets for sea lamprey selective toxic action is crucial to prioritizing chemical candidates. Targeted delivery or identifying synergists to existing or new lampricides can provide increased efficiency and reduced environmental impact. Ultimate development of next-generation lampricides will rely on traditional toxicity testing methodologies to ensure safety and regulatory compliance. Le succes de la gestion integree dans les Grands Lacs laurentiens de l'Amerique du Nord de la lamproie (Petromyzon marinus), un predateur envahissant, est en bonne partie du a l'utilisation efficace et soutenue de deux lampricides, le 3-trifluoromethyl-4-nitrophenol (TFM) et le 2',5-dichloro-4'-nitrosalicylanilide (niclosamide). Le maintien de l'efficacite de la lutte contre la lamproie requiert l'examen d'eventuels lampricides de nouvelle generation comme complements ou en remplacement des lampricides actuels. La presente synthese cerne 15 aspects cles expliquant l'efficacite des lampricides actuels a utiliser comme criteres de conception dans la quete de lampricides de nouvelle generation. Une approche de recherche a trois volets est decrite. Des travaux cibles faisant appel aux sciences omiques, a la modelisation par ordinateur et a des techniques de haute capacite pour definir les mecanismes moleculaires et des cibles moleculaires presentant une forte probabilite d'action toxique selective sur les lamproies sont d'importance cle pour la priorisation de substances chimiques candidates. La livraison ciblee et l'identification d'activateurs pour les lampricides actuels et de nouveaux lampricides peuvent rehausser l'efficacite et reduire l'impact environnemental. A terme, la mise au point de lampricides de nouvelle generation devra avoir recours a des methodes traditionnelles d'essai de toxicite afin d'en assurer l'innocuite et la conformite a la reglementation. [Traduit par la Redaction], 1. Introduction Aquatic nuisance species are a continuing threat to ecosystems and the economic stability of regions centered around those ecosystems (https://www.anstaskforce.gov). One of the most significant invasive species control [...]

In the Laurentian Great Lakes, the issue of barrier removal is complicated by the presence of non‐native species below barriers. A fish tracking study was conducted to guide efforts for barrier remediation decisions for the restoration of fish populations with a focus on Walleye (Scander vitreus) and Lake Sturgeon (Acipenser fulvescens) in the Black Sturgeon River, a river system fragmented by a dam which blocks access of fishes to the majority of a large, otherwise barrier‐free watershed. Data from 3 years of spawning migrations (2018–2020) indicated that the Walleye population in Black Bay likely consists of both river (65%) and lake spawners (27%), with the remaining individuals spawning in the bay or river in different years. Walleye and Lake Sturgeon showed consistent differences in the extent to which individuals migrated upstream in the river during the spawning season, despite expectations that both species would spawn at the base of the dam when prevented from further migration. The dam was presumably a barrier to migration for Lake Sturgeon, as nearly all Lake Sturgeon that entered the river migrated to the base of the dam. In contrast, few Walleye entering the river during the spawning season migrated to the dam annually. These findings suggest that Walleye and Lake Sturgeon may not benefit equally, at least in the short term, from barrier remediation or dam removal. [ABSTRACT FROM AUTHOR]

Probabilistic maturation reaction norms (PMRNs) are commonly used to infer evolution of maturation age and size in wild fish stocks, but how well estimates from phenotypic data actually reflect underlying genotypes is debated. We used an eco-genetic model of a commercially harvested freshwater fish to simulate populations undergoing various levels of fisheries-induced evolution and density-dependent feedback and evaluated effects on the estimation of PMRNs. We estimated PMRNs from phenotypic data sampled from simulated populations (age, length, and maturation status of individuals), as is done for wild stocks, and compared estimates with the known maturation genotypes of individuals in the simulated population. PMRN estimates were robust to changes in the strength of density-dependent growth and high levels of fisheries-induced evolution. However, our ability to detect slower rates of evolution was limited, especially when individuals matured within a narrow range of ages. Furthermore, low numbers of immature or mature individuals within a given age class limited our ability to robustly estimate midpoints for more than one or two ages, despite our large sample sizes (n = 200 randomly sampled individuals of each age per year), highlighting a challenge with this approach. Nonetheless, this study suggests that the widely applied method of estimating PMRNs from readily available phenotypic data to detect underlying evolution of maturation schedule is robust to some key factors that vary in wild populations. Si l'utilisation de normes de reaction probabilistes pour la maturation (NRPM) pour inferer l'evolution de l'age et de la taille a la maturation dans les stocks de poissons sauvages est repandue, un debat persiste concernant la mesure dans laquelle les estimations basees sur des donnees phenotypiques refletent les genotypes sous-jacents. Nous utilisons un modele ecogenetique d'un poisson d'eau douce faisant l'objet d'une exploitation commerciale pour simuler des populations presentant differents degres d'evolution induite par la peche et de retroaction dependante de la densite et en evaluons les effets sur l'estimation de NRPM. Nous estimons des NRPM a partir de donnees phenotypiques obtenues de populations simulees (age, longueur et etat de maturation d'individus), a l'instar de ce qui se fait pour les stocks sauvages, et comparons ces estimations aux genotypes de maturation connus d'individus dans la population simulee. Les estimations de NRPM sont robustes en presence de changements de la force de la croissance dependante de la densite et de degres eleves d'evolution induite par la peche. Notre capacite de deceler des vitesses d'evolution plus faibles est toutefois limitee, particulierement si les individus atteignent la maturite dans une fourchette d'ages restreinte. En outre, de faibles nombres d'individus immatures ou matures dans une classe d'age donnee limitent notre capacite d'estimer les valeurs medianes de maniere robuste pour plus d'un ou deux ages, malgre nos grands echantillons (n = 200 individus echantillonnes aleatoirement de chaque age par annee), faisant ressortir un des defis de cette approche. Quoi qu'il en soit, l'etude porte a croire que la methode repandue qui consiste a estimer les NRPM a partir de donnees phenotypiques facilement accessibles pour determiner l'evolution sous-jacente de la chronologie de la maturation est robuste en presence de variations de certains facteurs cles dans les populations sauvages. [Traduit par la Redaction], Introduction The timing of maturation plays an important role in determining the productivity and resilience of fish stocks. Changes in maturation traits, generally towards earlier maturation at smaller sizes, have [...]

Evolutionary effects of fishing can have unwanted consequences diminishing a fishery's value and sustainability. Reserves, or no-take areas, have been proposed as a management tool for reducing fisheries-induced selection, but their effectiveness for migratory species has remained unexplored. Here we develop an eco-genetic model to predict the effects of marine reserves on fisheries-induced evolution under migration. To represent a stock that undergoes an annual migration between feeding and spawning grounds, we draw model parameters from Atlantic cod (Gadus morhua) in the northern part of its range. Our analysis leads to the following conclusions: (i) a reserve in a stock's feeding grounds, protecting immature and mature fish alike, reduces fisheries-induced evolution, even though protected and unprotected population components mix on the spawning grounds; (ii) in contrast, a reserve in a stock's spawning grounds, protecting only mature fish, has little mitigating effects on fisheries-induced evolution and can sometimes even exacerbate its magnitude; (iii) evolutionary changes that are already underway may be difficult to reverse with a reserve; (iv) directly after a reserve is created or enlarged, most reserve scenarios result in yield losses; and (v) timescale is very important: short-term yield losses immediately after a reserve's creation can give way to long-term gains.

Evolutionary effects of fishing can have unwanted consequences diminishing a fishery's value and sustainability. Reserves, or no-take areas, have been proposed as a management tool for reducing fisheries-induced selection, but their effectiveness for migratory species has remained unexplored. Here we develop an eco-genetic model to predict the effects of marine reserves on fisheries-induced evolution under migration. To represent a stock that undergoes an annual migration between feeding and spawning grounds, we draw model parameters from Atlantic cod (Gadus morhua) in the northern part of its range. Our analysis leads to the following conclusions: (i) a reserve in a stock's feeding grounds, protecting immature and mature fish alike, reduces fisheries-induced evolution, even though protected and unprotected population components mix on the spawning grounds; (ii) in contrast, a reserve in a stock's spawning grounds, protecting only mature fish, has little mitigating effects on fisheries-induced evolution and can sometimes even exacerbate its magnitude; (iii) evolutionary changes that are already underway may be difficult to reverse with a reserve; (iv) directly after a reserve is created or enlarged, most reserve scenarios result in yield losses; and (v) timescale is very important: short-term yield losses immediately after a reserve's creation can give way to long-term gains.

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. L'exploitation peut modifier des caracteres phenotypiques de populations par le biais de consequences demographiques immediates, de reactions d'adaptation a la selection par la peche ou de reactions developpementales individuelles. L'etude examine les effets phenotypiques plastiques de l'exploitation sur la taille et l'age a la maturite chez un poisson d'eau douce faisant l'objet d'une exploitation commerciale. Nous avons mis a l'essai un modele individuel de plasticite de la croissance et du cycle biologique qui utilise des correlations decalees incorporant l'influence de la peche de poissons de 2 ans et plus sur l'abondance de poissons juveniles, la disponibilite des ressources, les taux de croissance individuelle et les reactions de l'age et de la taille a la maturite en decoulant. Pour ce faire, nous avons utilise des donnees de cohorte pour la perchaude du lac Erie (Perca flavescens). De 1991 a 2013, l'age et la taille a la maturite ont presente des fluctuations importantes et rapides qui indiqueraient une forte contribution de la plasticite phenotypique a la dynamique de la maturation. Les changements associes a la maturite ne peuvent etre expliques par des reactions a l'exploitation, comme le predit le modele de plasticite. Dans le lac Erie, l'age et la taille a la maturite chez les perchaudes semblent reagir a d'autres facteurs, comme la dynamique induite par la peche d'autres stocks de poissons ou des changements ecosystemiques independants de l'exploitation. [Traduit par la Redaction], Introduction The prominent trends in phenotypic traits observed in exploited populations suggest the effects of harvest can extend beyond demographic changes in population size, age structure, and sex ratio (Jorgensen [...]

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. Resume : L'evolution rapide de populations d'organismes nuisibles, de pathogenes et d'animaux sauvages peut avoir des effets indesirables comme, par exemple, des insectes qui developpent une resistance aux pesticides ou une diminution de la taille du corps des poissons en reponse a la peche. Le pesticide 3-trifluoromethyl-4-nitrophenol (TFM) est utilise depuis les annees 1950 pour lutter contre la lamproie (Petromyzon marinus), une espece envahissante destructrice dans les Grands Lacs laurentiens. Nous avons evalue la probabilite que les lamproies developpent une resistance au TFM par (i) l'examen du cycle biologique des lamproies et des methodes de lutte contre cette espece, (ii) la determination des strategies de resistance physiologiques et comportementales (iii) l'estimation de la force de la selection decoulant du TFM, (iv) revaluation de la duree necessaire pour qu'il y ait evolution et (v) l'analyse de donnees historiques sur la toxicite pour voir s'il existe des indices de resistance. Le nombre de generations de lamproies exposees au TFM est dans la fourchette observee pour les populations de poissons ayant subi une evolution rapide. La mortalite causee par le TFM est estimee a 82-90 %, ce qui indiquerait une pression de selection significative. Cependant, 57 annees de donnees sur la toxicite ne revelent aucune augmentation des concentrations letales de TFM. La vigilance et la mise au point d'autres mesures de lutte sont necessaries pour empecher cette espece aquatique envahissante de developper des strategies lui permettant de contrer les efforts de lutte. [Traduit par la Redaction], Introduction The capability of pathogens and pests to evolve resistance to control measures is a global concern with implications for human health, natural resource management, and agriculture (Palumbi 2001). Resistance [...]

Introduction Drastic recent and ongoing changes to fish populations and food webs in the Great Lakes have been well-described (Riley et al. 2008; Barbiero et al. 2009; Nalepa et al. [...]