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Laboratory-based studies of locomotory performance in many taxa have noted that individuals form stable hierarchies of organismal performance. Though laboratory studies of teleost fishes have consistently demonstrated individual repeatability of swimming performance, this phenomenon has rarely been studied in the field and never across multiple years. Using a whole-lake acoustic telemetry array with submetre accuracy, we assessed the individual repeatability of two metrics of swimming performance (daily distance traveled and mean daily swimming speed) within four seasons during a year (fall, winter, spring, and summer), among these seasons, and between winters of 2 years. Largemouth bass (Micropterus salmoides (Lacepède, 1802)) formed stable performance hierarchies within seasons except spring and no sex-specific differences in rankings were noted. Individual swimming performance was not repeatable among seasons during 1 year or across multiple winters. Seasonal changes in environmental and intrinsic biological conditions appear to result in a reshuffling of performance hierarchies, perhaps reflecting individual differences in organismal physiology. [ABSTRACT FROM AUTHOR]

In this study, field biotelemetry and laboratory physiology approaches were coupled to allow understanding of the behavioral and physiological responses of fish to winter hypoxia. The biotelemetry study compared dissolved oxygen levels measured throughout the winter period with continually tracked locations of nine adult largemouth bass obtained from a whole-lake submerged telemetry array. Fish habitat usage was compared with habitat availability to assess whether fish were selecting for specific dissolved oxygen concentrations. The laboratory study examined behavioral and physiological responses to progressive hypoxia in juvenile largemouth bass acclimated to winter temperatures. Results from the dissolved oxygen measurements made during the biotelemetry study showed high variance in under-ice dissolved oxygen levels. Avoidance of water with dissolved oxygen <2.0 mg/L by telemetered fish was demonstrated, but significant use of water with intermediate dissolved oxygen levels was also found. Results from the lab experiments showed marked changes in behavior (i.e., yawning and vertical movement) at <2.0 mg/L of dissolved oxygen but no change in tissue lactate, an indicator of anaerobic metabolism. Combined results of the biotelemetry and laboratory studies demonstrate that a dissolved oxygen content of 2.0 mg/L may be a critical threshold that induces behavioral responses by largemouth bass during the winter. In addition, the use by fish of areas with intermediate levels of dissolved oxygen suggests that there are multiple environmental factors influencing winter behavior. [ABSTRACT FROM AUTHOR]

The behaviour of free-swimming, telemetered, adult largemouth bass, Micropterus salmoides (L.), was monitored using a whole lake, three-dimensional acoustic telemetry array to test the hypothesis that fish activity and depth distribution are influenced by lunar phase. The percent of lunar face shining and whether the moon was waxing or waning were significant determinants of swimming activity and depth distribution during most of the lunar cycles evaluated, although these patterns were not consistent across the year. In spring and summer, daily depth distribution followed a pattern in which the fish inhabited greater depths on the 26–50% and 51–75% waxing moon. Fish daily movement distances were five times greater during spring and summer than in winter, but no repeatable patterns were noted in relation to lunar periodicity. This research suggests that solunar tables frequently consulted by recreational anglers may have little predictive value for identifying peak fishing time. [ABSTRACT FROM AUTHOR]

Because fish are poikilothermic, water temperature is regarded as a primary factor influencing their activity and behaviour. Rarely have field studies been conducted with the spatiotemporal resolution to enable rigorous quantitative assessments of that relationship. Furthermore, there have been few studies that have considered the influence of sex on the seasonal behaviour of fish. Twenty largemouth bass (Micropterus salmoides (Lacepède, 1802)) were implanted with coded acoustic telemetry transmitters and remotely tracked in near real time in a small lake in Ontario, Canada, via a whole-lake hydrophone array between 1 November 2004 and 30 September 2005. Fish inhabited the deepest waters and were least active during the winter months under ice. During the warmest months, fish were most active and inhabited the littoral zone. Sex-specific differences were noted year-round. Reproductive males were less active and inhabited shallower depths during the spawning and post-reproductive periods. Reproductive males inhabited the deepest depths during winter and fall, with nonreproductive males at the shallowest depths. Throughout the year, the behaviour of nonreproductive males and females was similar. While differences in behaviour of bass are primarily driven by water temperature, sex and reproductive status play important roles year-round, especially during and after the reproductive period. Parce que les poissons sont des poïkilothermes, la température de l’eau est considérée comme un des facteurs principaux qui influencent leur activité et leur comportement. De rares études ont été menées à une échelle spatio-temporelle assez fine pour permettre des évaluations quantitatives rigoureuses de cette relation. De plus, peu d’études ont pris en considération l’influence du sexe sur le comportement saisonnier des poissons. Nous avons muni 20 achigans à grande bouche (Micropterus salmoides (Lacepède, 1802)) d’émetteurs acoustiques codés de télémétrie et nous les avons suivis en temps quasi réel dans un petit lac de l’Ontario, Canada, à l’aide d’un réseau d’hydrophones répartis sur l’ensemble du lac entre le 1er novembre 2004 et le 30 septembre 2005. Les poissons se retrouvent dans les eaux les plus profondes et sont le moins actifs durant les mois d’hiver sous la glace. Durant les mois les plus chauds, les poissons sont le plus actifs et ils habitent la zone littorale. Il existe des différences spécifiques au sexe pendant toute l’année. Les mâles reproducteurs sont moins actifs et se retrouvent dans les eaux les moins profondes durant la fraye et la période qui suit la reproduction. Les mâles reproducteurs sont dans les profondeurs les plus grandes durant l’hiver et l’automne, alors que les mâles non reproducteurs se trouvent dans les sites moins profonds. Durant toute l’année, les comportements des mâles non reproducteurs et des femelles sont semblables. Bien que les différences de comportement des achigans s’expliquent principalement par la température de l’eau, le sexe et le statut reproducteur jouent un rôle important pendant toute l’année, mais particulièrement durant et après la période de reproduction. [ABSTRACT FROM AUTHOR]

A whole-lake acoustic telemetry observatory situated in eastern Ontario was used to continuously monitor the three-dimensional position of 20 largemouth bass ( Micropterus salmoides) over a 120-h period during the winter and a separate 120-h period during the early spring. These data were used to evaluate the frequency and stability of associations among fish to provide an understanding of seasonal aggregations and the sociobiology of largemouth bass. The temporal and spatial proximity of each fish relative to the other 19 individuals was assessed and, based on our definition of spatial/temporal proximity (i.e., two fish having an average hourly position <2 m apart), associations were shown to vary among fish, as well as diurnally, daily and seasonally. Associations during the winter were found to be more stable and involved fewer fish than associations during the spring. Of those fish that formed pair aggregations during the winter and spring study periods, male–female pairs occurred more often than male–male and female–female pairs. Our analysis also demonstrated that associations occurred primarily during daylight hours, suggesting that fish may use visual cues to form these aggregations. [ABSTRACT FROM AUTHOR]