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Carbon dioxide (C[O.sub.2]) in water has been explored for use as an invasive species deterrent system. To date, studies have not determined C[O.sub.2] avoidance by fish in flowing water, and this is a necessary step before an operational deterrent system can be implemented. The objective of the study was to define how flowing water influences the response of bighead carp (Hypophthalmichthys nobilis) to continuous plugs of C[O.sub.2]. A choice experiment by which C[O.sub.2] was injected into channels of an annular flowing water flume was completed. In trials when C[O.sub.2] was injected into the inner vein, fish spent less time in the vein when compared with control conditions. An increased amount of lateral movements and reduced performance were also observed when fish were exposed to elevated C[O.sub.2]. The study demonstrates that bighead carp in flowing water enriched with C[O.sub.2] move away, a finding consistent with static water experiments. Le dioxyde de carbone (C[O.sub.2]) dans l'eau a ete etudie en vue de son utilisation comme systeme de dissuasion d'especes envahissantes. A ce jour, les etudes n'ont pas etabli s'il y a evitement du C[O.sub.2] par les poissons dans l'eau mouvante, bien qu'il s'agisse d'une etape prealable necessaire a la mise en reuvre de tout systeme de dissuasion. L'objectif de la presente etude etait d'etablir comment l'eau mouvante influence la reaction de carpes a grosse tete (Hypophthalmichthys nobilis) a des bouffees continues de C[O.sub.2]. Une experience de choix dans laquelle du C[O.sub.2] est injecte dans les chenaux d'un canal annulaire d'eau mouvante a ete realisee. Dans les essais, quand du C[O.sub.2] etait injecte dans la veine interieure, les poissons y passaient moins de temps que dans les conditions de reference. Plus de deplacements lateraux et une performance plus faible etaient aussi observes quand les poissons etaient exposes a des concentrations elevees de C[O.sub.2]. L'etude demontre que les carpes a grosse tete dans de l'eau mouvante enrichie en C[O.sub.2] s'en eloignent, une constatation qui concorde avec les resultats d'experiences en eau stationnaire. [Traduit par la Redaction], Introduction Aquatic invasive species (AIS) are prevalent across the planet, and management tools are often used to control their spread (Vander Zanden and Olden 2008). Specifically, for freshwater fish, unfettered [...]

Lakes respond heterogeneously to climate, with implications for fisheries management. We analyzed walleye (Sander vitreus) recruitment to age-0 in 359 lakes in Wisconsin, USA, to (i) quantify the relationship between annual water temperature degree days (DD) and walleye recruitment success and (ii) identify the influence of lake characteristics--area, conductivity, largemouth bass (Micropterus salmoides) catch rates, and mean DD--on this relationship. The relationship between walleye recruitment and annual DD varied among lakes and was not distinguishable from zero overall (posterior mean = -0.11, 90% CI = -0.34,0.15). DD effects on recruitment were negative in 198 lakes (55%) and positive in 161(45%). The effect of annual DD was most negative in lakes with high largemouth bass densities, and, on average, the probability of recruitment was highest in large lakes with low largemouth bass densities. Conductivity and mean DD influenced neither recruitment nor the effect of annual DD. Walleye recruitment was most resilient to warming in lakes with few largemouth bass, suggesting that the effects of climate change depend on lake-specific food-web and habitat contexts. Les lacs ne reagissent pas au climat de maniere uniforme, ce qui a des consequences sur la gestion des peches. Nous avons analyse le recrutement de dores jaunes (Sander vitreus) de moins de 1 an dans 359 lacs du Wisconsin (Etats-Unis) pour (i) quantifier la relation entre les degres-jours (DJ) annuels de temperature de l'eau et le succes du recrutement de dores jaunes et (ii) cerner l'influence des caracteristiques du lac--superficie, conductivite, taux de prise d'achigans a grande bouche (Micropterus salmoides) et DJ moyens--sur cette relation. La relation entre le recrutement de dores jaunes et les DJ annuels varie selon le lac et, en general, s'assimile a zero (moyenne posterieure = -0,11, IC 90 % = -0,34, 0,15). Les effets des DJ sur le recrutement etaient negatifs dans 198 lacs (55 %) et positifs dans 161 lacs (45 %). L'effet des DJ annuels etait le plus negatif dans les lacs a forte densite d'achigans a grande bouche et, en moyenne, la probabilite de recrutement etait la plus elevee dans les lacs a faible densite d'achigans a grande bouche. La conductivite et les DJ moyens n'exerqaient pas d'influence sur le recrutement ni sur l'effet des DJ annuels. Le recrutement de dores jaunes presentait la plus forte resilience au rechauffement dans les lacs avec peu d'achigans a grande bouche, ce qui semble indiquer que les effets des changements climatiques dependent des contextes trophiques et d'habitats propres au lac. [Traduit par la Redaction], Introduction Understanding how lakes respond to natural and anthropogenic environmental change is critical to the ecological and economic management of lacustrine resources. (Woodward et al. 2010; Carpenter et al. 2011). [...]

Abstract--Examination of otolith morphometric variation has been shown to provide improved descriptions of stock structure for several marine fish species. We examined spatial variation in otolith shape of southern flounder [...]