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Catch‐and‐release (C&R) angling is often used to maintain high catch rates but fish vulnerability to capture may decrease following hooking, thereby decreasing angler catch per unit effort (CPUE) (hyperdepletion). To determine if fish post‐capture response affected recapture probability and population‐level CPUE, individual capture histories of Largemouth Bass in two lakes were compared before and after doubling angling effort in a Before‐After Control‐Impact (BACI) analysis. Previous capture and day‐of‐season both affected recapture probability. Counteracting effects of previous capture and reduced late‐season catch rates caused no hyperdepletion of angler CPUE. Our results highlight the complexity of fish behavioral responses to angling and suggest that hyperdepletion of angling catch rates may not be an issue in C&R fisheries. [ABSTRACT FROM AUTHOR]

The relationship between angler catch rates and fish abundance can contribute to or hinder sustainable exploitation of fisheries depending on whether catch rates are proportional to fish abundance or are hyperstable. We performed a whole-ecosystem experiment in which fish abundance was manipulated and paired with weekly angler catch rate estimates from controlled experimental fishing. Catch rates were hyperstable ([beta] = 0.47) in response to changes in fish abundance. By excluding effort sorting (i.e., catch rates remaining high because less skilled anglers leave the fishery as abundance declines), our experiment isolated the influence of fish aggregation as a driver of hyperstability. Spatial analysis of catch locations did not identify clustering around specific points, suggesting that loose aggregation to preferred habitat at the scale of the entire littoral zone was enough to maintain stable catch rates. In our study, general, non-spawning, habitat preferences created loose aggregations for anglers to target, which was sufficient to generate hyperstability. Habitat preferences are common to nearly all fishes and widely known to anglers, suggesting that many harvest-oriented recreational fisheries can be expected to exhibit hyperstability. La relation entre les taux de prise de pecheurs a la ligne et l'abondance de poissons peut contribuer a l'exploitation durable de ressources halieutiques ou lui faire entrave, selon que les taux de prise sont proportionnels a l'abondance de poissons ou hyperstables. Nous avons mene une experience a l'echelle ecosystemique dans laquelle l'abondance de poissons a ete manipulee et jumelee a des estimations des taux de prise hebdomadaires des pecheurs pour des peches experimentales controlees. Les taux de prise etaient hyperstables ([beta] = 0,47) en reponse a des changements de l'abondance de poissons. En excluant le tri de l'effort (c.-a-d. des taux de prise demeurant eleves parce que les pecheurs moins competents delaissent la peche quand l'abondance baisse), l'experience a isole l'influence du regroupement de poissons comme facteur d'hyperstabilite. L'analyse spatiale de l'emplacement des prises n'a pas releve de concentrations autour de lieux precis, ce qui indiquerait qu'un regroupement lache autour des habitats de predilection a l'echelle de toute la zone littorale suffit pour maintenir des taux de prise stables. Dans l'etude, les preferences generales en matiere d'habitat, autres que pour le frai, creaient des regroupements laches pouvant etre cibles par les pecheurs, ce qui suffisait pour produire une hyperstabilite. Presque tous les poissons montrent des preferences en matiere d'habitat, que les pecheurs generalement, ce qui donne a penser que de nombreuses peches recreatives axees sur la capture devraient presenter une hyperstabilite. [Traduit par la Redaction], Introduction The relationship between catch per unit effort (CPUE) and fish abundance plays a critical role in sustainable exploitation of fisheries. Ideally, CPUE is proportional to abundance, signaling fishers to [...]

A focus on the phenotypic characteristics of microorganisms-their traits-offers a path for interpreting the growing amount of microbiome data. We review key aspects of microbial traits, as well as approaches used to assay their phylogenetic distribution. Recent studies reveal that microbial traits are differentially conserved across the tree of life and appear to be conserved in a hierarchical fashion, possibly linked to their biochemical complexity. These results suggest a predictive framework whereby the genetic (or taxonomic) resolution of microbiome variation among samples provides information about the traits under selection. The organizational parallels seen among human and free-living microbiomes seem to support this idea. Developments in this framework may offer predictions not only for how microbial composition responds to changing environmental conditions, but also for how these changes may alter the health or functioning in human, engineered, and environmental systems.

Microbial communities typically contain many rare taxa that make up the majority of the observed membership, yet the contribution of this microbial "rare biosphere" to community dynamics is unclear. Using 16S rRNA amplicon sequencing of 3,237 samples from 42 time series of microbial communities from nine different ecosystems (air; marine; lake; stream; adult human skin, tongue, and gut; infant gut; and brewery wastewater treatment), we introduce a new method to detect typically rare microbial taxa that occasionally become very abundant (conditionally rare taxa [CRT]) and then quantify their contributions to temporal shifts in community structure. We discovered that CRT made up 1.5 to 28% of the community membership, represented a broad diversity of bacterial and archaeal lineages, and explained large amounts of temporal community dissimilarity (i.e., up to 97% of Bray-Curtis dissimilarity). Most of the CRT were detected at multiple time points, though we also identified "one-hit wonder" CRT that were observed at only one time point. Using a case study from a temperate lake, we gained additional insights into the ecology of CRT by comparing routine community time series to large disturbance events. Our results reveal that many rare taxa contribute a greater amount to microbial community dynamics than is apparent from their low proportional abundances. This observation was true across a wide range of ecosystems, indicating that these rare taxa are essential for understanding community changes over time. Importance: Microbial communities and their processes are the foundations of ecosystems. The ecological roles of rare microorganisms are largely unknown, but it is thought that they contribute to community stability by acting as a reservoir that can rapidly respond to environmental changes. We investigated the occurrence of typically rare taxa that very occasionally become more prominent in their communities ("conditionally rare"). We quantified conditionally rare taxa in time series from a wide variety of ecosystems and discovered that not only were conditionally rare taxa present in all of the examples, but they also contributed disproportionately to temporal changes in diversity when they were most abundant. This result indicates an important and general role for rare microbial taxa within their communities.

Littoral structure is often assumed to provide refuge to young of year (YOY) freshwater fish species, but empirical in situ tests of this relationship are lacking. We estimated mortality rates of YOY largemouth bass (Micropterus salmoides) over the open-water season in 13 lakes in northern Wisconsin and Michigan using repeated snorkel surveys. Our goal was to test the hypothesis that mortality rate is negatively related to the abundance of littoral coarse woody habitat, which ranged from 3 to 1500 pieces of wood per kilometre of shoreline in these lakes. Instantaneous mortality rates were well-constrained and ranged from 0.04 to 0.19 among the 13 lakes. Mortality was not related to coarse woody habitat abundance. Our results suggest that the relationship between coarse woody habitat and YOY mortality might not be as strong or universal as is often assumed. Il est souvent tenu pour acquis que la structure littorale fournit des refuges aux jeunes de l'annee d'especes de poissons d'eau douce, mais des tests empiriques in situ pour verifier cette relation sont insuffisants. Nous avons estime les taux de mortalite d'achigans a grande bouche (Micropterus salmoides) jeunes de l'annee durant la periode d'eau libre dans 13 lacs du nord du Wisconsin et du Michigan, en utilisant des releves de plongee en apnee repetes. L'objectif etait de verifier l'hypothese selon laquelle le taux de mortalite est negativement relie a l'abondance d'habitats littoraux a materiaux ligneux grossiers, qui contiennent de 3 a 1500 morceaux de bois au km de rive dans ces lacs. La fourchette de taux de mortalite instantanes a ete bien delimitee, allant de 0,04 a 0,19 dans ces 13 lacs. La mortalite n'etait pas reliee a l'abondance d'habitats a materiaux ligneux grossiers. Nos resultats donnent a penser que la relation entre les habitats a materiaux ligneux grossiers et la mortalite des jeunes de l'annee peut ne pas etre aussi forte ou universelle que ce qui est souvent tenu pour acquis. [Traduit par la Redaction], Introduction Young of year (YOY) mortality is an important determinant of population dynamics, and minimizing YOY mortality can increase productivity and resilience of fish populations. Literature reviews of experiments focused [...]

Negative relationships between dissolved organic carbon (DOC) concentration and fish productivity have been reported from correlative studies across lakes, but to date there have not been experimental tests of these relationships. We increased the DOC concentration in a lake by 3.4 mg x [L.sup.-1], using a before-after control-impact design, to quantify the effects on the productivity and population structure of largemouth bass (Micropterus salmoides). Greater DOC reduced the volume of the epilimnion, the preferred habitat of largemouth bass, resulting in increased bass density. The likelihood that adult bass had empty diets decreased despite this increase in bass density; diet composition also changed. There was no apparent change in bass growth or condition. Overall, there was no net change in largemouth bass productivity. However, changes in young of year and juvenile recruitment and feeding success suggest the possibility that future effects could occur. Our results are the first to examine the effects of an increase in DOC on fish productivity through a 5-year temporal lens, which demonstrates that the relationship between DOC and fish productivity is multidimensional and complex. Des etudes correlatives sur des lacs multiples ont fait etat de relations negatives entre la concentration de carbone organique dissous (COD) et la productivite de poissons, mais aucun test experimental permettant de valider ces relations n'a ete propose a ce jour. Nous avons accru la concentration de COD dans un lac de 3,4 mg x [L.sup.-1] et employe un schema avant-apres temoin-intervention pour quantifier les effets sur la productivite et la structure de la population d'achigans a grande bouche (Micropterus salmoides). Une plus grande concentration de COD s'est traduite par une reduction du volume de l'epilimnion, l'habitat privilegie des achigans a grande bouche, entrainant une augmentation de la densite d'achigans. La probabilite que des achigans adultes aient des regimes alimentaires vides a diminue malgre la densite accrue d'achigans; la composition des regimes alimentaires a egalement change. La croissance et l'embonpoint des achigans ne presentent pas de changement apparent. Globalement, il n'y a pas eu de changement net de la productivite des achigans a grande bouche. Cependant, des modifications du recrutement de jeunes de l'annee et de juveniles et du succes d'alimentation indiqueraient que des effets futurs sont possibles. Nos resultats sont les premiers a examiner les effets d'une augmentation du COD sur la productivite de poissons dans une optique quinquennale, qui demontre que la relation entre le COD et la productivite de poissons est complexe et multidimensionnelle. [Traduit par la Redaction], Introduction Dissolved organic carbon (DOC) concentrations vary widely across lake-rich landscapes, and many lakes in the Northern Hemisphere are increasing in DOC (Hanson et al. 2007; Monteith et al. 2007). [...]

Two primer sets for automated ribosomal intergenic spacer analysis (ARISA) are used for assessing the bacterial community composition (BCC) in Lake Mendota, Wisconsin. The analysis has shown that ARISA is a powerful tool for evaluating the changes in BCC through space and time, regardless of the specific primer set used.