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Objective: Efficiently managing sea lice on salmon farms through active surveillance, crucial for lice abundance estimation, is challenging due to the need for effective sampling schemes. To address this, we developed an application that considers infestation levels, farm structure, and management protocols, enhancing the precision of sampling strategies for sea louse abundance estimation. Methods: Simulation‐based methods are valuable for estimating suitable sample sizes in complex studies where standard formulae are inadequate. We introduce FishSampling, an open Web‐based application tailored to determine precise sample sizes for specific scenarios and objectives. Result: The model incorporates factors such as sea lice abundance, farm pen numbers, potential clustering effects among these pens, and the desired confidence level. Simulation outcomes within this application provide practical advice on how to decide on the number of fish and pens to sample, under varying levels of assumed clustering. Conclusion: This approach can be used across the salmon aquaculture sector to improve sampling strategies for sea lice abundance estimation and balance surveillance costs against health objectives. Impact statementThe open‐source application FishSampling enhances sea lice monitoring on salmon farms with a novel simulation‐based approach for sample size determination. It offers precise estimates of sea lice abundance, crucial for regulatory purposes, and aids in the efficient allocation of sampling resources. [ABSTRACT FROM AUTHOR]

Warming waters are changing marine pathogen dispersal patterns and infectivity worldwide. Coupled biological--physical modelling has been used in many systems to determine the connectivity of metapopulations via infectious disease particles. Here we model the connectivity of sea lice larvae (Lepeophtheirus salmonis) among salmon farms in the Broughton Archipelago, British Columbia, Canada, using a coupled biological-physical model. The physical model simulated pathogen dispersal, while the biological component influenced the survival and developmental rates of the sea lice. Model results predicted high temporal variability in connectivity strength among farms, an emergent effect from the interacting parts of the simulation (dispersion versus survival and development). Drivers of temporal variability were disentangled using generalized additive modeling, which revealed the variability was most strongly impacted by the spring freshet, which can act as a natural aid for sea lice control in the Broughton Archipelago. Our results suggest that farm management strategies can benefit by accounting for short-term spikes in regional pathogen connectivity among farms. Additionally, future scenarios of a warming climate with reduced snowpack can make sea lice control more challenging. Le rechauffement des eaux modifie les motifs de dispersion et l'infectiosite des pathogenes marins a l'echelle planetaire. La modelisation couplee biologique-physique a ete utilisee dans de nombreux systemes pour determiner la connectivite de metapopulations par le biais de particules de maladie infectieuse. Nous modelisons la connectivite des larves de pou du poisson (Lepeophtheirus salmonis) entre des fermes salmonicoles de l'archipel Broughton (Colombie-Britannique, Canada), en utilisant un modele couple biologique-physique. Le modele physique simule la dispersion du pathogene, alors que la composante biologique influence les taux de survie et de developpement des poux du poisson. Les resultats du modele predisent une forte variabilite temporelle de la force de la connectivite entre les fermes, un effet emergent decoulant des aspects interdependants de la simulation (dispersion et survie et developpement). Les facteurs de variabilite temporelle sont demeles en utilisant un modele additif generalise, qui revele que la crue printaniere exerce la plus forte influence sur la variabilite et peut servir de mecanisme naturel pour lutter contre les poux du poisson dans l'archipel Broughton. Nos resultats donnent a penser que la prise en compte de pointes de courte duree de la connectivite regionale de pathogenes entre les fermes peut ameliorer les strategies de gestion des fermes. Les scenarios de rechauffement climatique futur et de reduction associee du manteau neigeux pourraient en outre rendre la lutte contre les poux du poisson plus difficile. [Traduit par la Redaction], Introduction Transmission of water-borne pathogens (parasites, viruses, bacteria) in marine environments depends on factors influencing the movement and viability of the pathogen. Passive dispersal depends on local hydrodynamics, as dictated [...]

Sea lice are common ectoparasites of farmed and wild salmonids and can cause substantial morbidity and mortality in their hosts. While sea lice infections are common in estuarine areas with variable salinity, the effects of salinity on population dynamics are poorly understood. We used existing literature to parameterize salinity-dependent logistic mortality curves for different life stages of sea lice. We then used population matrix models to characterize the effects of temperature and salinity on sea louse population growth. Our models showed that low salinity decreases survival, while low temperature retards sea louse development. In contrast with the linear effects of temperature on sea louse development, salinity has a nonlinear effect on sea louse survival; values below 20 psu cause mortality, while values above 20 psu have little effect on survival. Simulations showed that sea louse population growth can be greatest in zones that are intermediate between estuarine and oceanic. In these cases population growth is not limited by the low salinities found in more estuarine sites or the low temperatures found in more oceanic sites. Les poux du poisson sont des ectoparasites repandus chez les salmonides sauvages et d'elevage qui peuvent entrainer une morbidite et une mortalite importantes chez leurs hotes. Si les infections aux poux du poisson sont courantes dans les zones estuariennes de salinite variable, les effets de la salinite sur la dynamique des populations demeurent meconnus. Nous avons utilise la documentation existante pour parametrer les courbes logistiques de mortalite dependante de la salinite pour differentes etapes du cycle de vie du pou du poisson. Nous avons ensuite utilise des modeles matriciels de population pour caracteriser les effets de la temperature et de la salinite sur la croissance des populations de poux du poisson. Nos modeles montrent qu'une faible salinite reduit la survie, alors qu'une faible temperature ralentit le developpement du pou du poisson. Contrairement aux effets lineaires de la temperature sur le developpement du pou du poisson, la salinite a un effet non lineaire sur la survie des poux du poisson, des valeurs inferieures a 20 psu entrainent une mortalite, alors que des valeurs superieures a 20 psu ont peu d'effet sur leur survie. Des simulations montrent que la croissance des populations de poux du poisson peut etre maximum dans les zones intermediates entre l'estuaire et l'ocean, ou la croissance des populations n'est pas limitee par les faibles taux de salinite observes dans des sites plus estuariens ou par les faibles temperatures observees dans des sites plus oceaniques. [Traduit par la Redaction], Introduction Marine diseases can have dramatic impacts on populations, with consequences for community structure, ecosystem function, and, when commercial species are involved, economics (Burge et al. 2014; Lafferty et al. [...]

Provides an overview of recent developments relating to the application of thesauri in information organization and retrieval on the World Wide Web. Discusses recent thesaurus projects; types of thesauri on the Web; thesauri integrated within databases and information retrieval systems; multiple thesaurus systems; standards for electronic thesauri; and future concerns. (Author/LRW)

A method of dating the marine growth circuli on Atlantic salmon (Salmo salar L.) scales is presented. Data were available for 54 salmon, intercepted as smolts at the completion of their downstream migration in the River North Esk, Scotland. Smolts were tagged, released, and recaptured as return adults after either one (1SW) or two (2SW) winters at sea. Dating of circuli was achieved by fitting a simple quadratic model to the circuli pertaining to fixed points on the scale. For 1SW fish, the latter were the dates of river emigration and completion of marine migration, and the midpoint circulus (equal to the winter solstice) of the winter annulus. For 2SW salmon, these were the date of emigration and the two winter annulus midpoints. A key assumption is that winter annulus formation arises from constraints of light availability on foraging, and hence, reduced growth rate. Comparative analyses indicate the method to be robust and effectively transferable to salmon of known capture date--but of unknown smolt emigration date--by assuming a fixed date of emigration; in such cases, circuli could still be allocated with confidence to a calendar month. Une methode de datation des stries de croissance en mer sur les ecailles de saumon atlantique (Salmo salar L.) est decrite. Des donnees etaient disponibles pour 54 saumons interceptes au stade de saumoneau a la fin de leur avalaison dans la riviere North Esk, en Ecosse. Les saumoneaux ont ete marques, relaches, puis repris en tant qu'adultes a leur retour apres un (1SW) ou deux (2SW) hivers en mer. La datation des stries a ete effectuee en calant un modele quadratique simple sur les stries reliees a des points fixes sur l'ecaille. Pour les poissons 1SW, ces points etaient les dates de l'emigration de la riviere et de la fin de la migration marine, ainsi que la strie mediane (egal au solstice d'hiver) de l'anneau hivernal. Pour les saumons 2SW, il s'agissait de la date d'emigration de la riviere et des stries medianes des deux anneaux hivernaux. La methode repose notamment sur l'hypothese voulant que la formation des anneaux hivernaux soit causee par des restrictions a l'alimentation associees a la lumiere disponible et, donc, a une reduction du taux de croissance. L'analyse comparative indique que la methode est robuste et peut etre appliquee avec succes a des saumons dont la date de capture est connue (mais dont la date d'emigration en tant que saumoneaux est inconnue) en postulant une date d'emigration fixe; dans ces cas, les stries peuvent quand meme etre affectees avec confiance a un mois precis. [Traduit par la Redaction], Introduction Teleost fish scales can provide a nonlethal and detailed source of archival information on the growth experience and life history of individuals, and of ecological responses of populations over [...]