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Book Patterns Predictors and Consequences of Space Use in Individually Tagged Young of the year Atlantic Salmon Salmo Salar

Download or read book Patterns Predictors and Consequences of Space Use in Individually Tagged Young of the year Atlantic Salmon Salmo Salar written by Stefán Óli Steingrímsson and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Movement, at various spatial and temporal scales, plays a major role in shaping the ecology of animals at the individual and the population level. In this study, I applied recently developed tagging methods (visible implant fluorescent elastomers) to examine the space use of Atlantic salmon (Salmo salar) during their first growing season. First, I monitored 320 YOY salmon to test alternative views on the patterns (restricted vs. not-restricted), causes (competition vs. habitat use) and consequences (mobile fish of lower vs. equal fitness) of movement in stream fish. Most fish (mean = 63.8%) stayed in the study sites (10-120m) throughout their respective study season (28-74 days), and 61.8% of the re-sighted fish moved less than 1 m up- or downstream. Fish originally found in slow water moved farther than fish from fast water, and fish found at high population density were more likely to disappear than fish from low density. Mobile fish grew as fast, or faster, than more sedentary fish, suggesting that movement can be advantageous. Second, I mapped the daily territories of tagged YOY salmon to test if the typical single-central-place view of territoriality among YOY salmonids holds when fish are followed for longer periods, at low population densities. In contrast to earlier studies, YOY salmon visited several foraging stations (median = 12.5; range = 3-26) within their territories, and showed limited fidelity to any particular station. When mapped around several stations, rather than assuming one station as is customary, territories of YOY salmon were larger than previous reported (mean = 0.932 m 2), were less circular in shape, and were elongated along the stream length rather than the stream width. Although the study fish used large multiple-central-place territories, aggressive acts directed toward other YOY Atlantic salmon were usually found on the outskirts of these areas, suggesting these were fairly efficiently defended against conspecifics. A literature review suggested that YOY salmonids defend small territories from one central-place foraging station at high population density, but use several stations and large territories at low density. Third, as current velocity, prey abundance and prey mobility increase, stream-fish are predicted to become less mobile, use smaller home ranges, and become more aggressive as they switch from "cruising" to "sit-and-wait" foraging. I tested if these predictions held for YOY Atlantic salmon that specialize as sit-and-wait foragers, but vary in the number of foraging stations visited and the distance traveled within a territory (15.7-95.0 m/40min). As predicted, territory size decreased with increasing current velocity and prey availability. YOY salmon, however, were most mobile and attacked intruders more often at intermediate, optimal, current velocities. These findings, and the fact that fish in slow water do not feed more on benthic prey than fish in fast water, suggest that mobility in YOY Atlantic salmon reflects the patrolling of territories, rather than just the direct exploitation of other food resources than drifting prey.

Book Dissertation Abstracts International

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Allometry of Territory Size and Metabolic Rate as Predictors of Self thinning in Young of the year Atlantic Salmon Salmo Salar

Download or read book The Allometry of Territory Size and Metabolic Rate as Predictors of Self thinning in Young of the year Atlantic Salmon Salmo Salar written by Stefán Óli Steingrímsson and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-thinning is a progressive decline in population density caused by competitively induced losses in a cohort of growing individuals and is frequently depicted as: $\log\sb?$ (density) = $\rm c -\beta\log\sb?$ (body mass). In mobile animals, two self-thinning mechanisms have been proposed. The territory-size hypothesis predicts that maximum population density for a given body size is set by the allometry of territory size. The energetic equivalence hypothesis suggests that if there is a constant amount of energy flowing through a population, the self-thinning slope is set by the allometry of metabolic rate. I tested the predictions of both hypotheses by monitoring body size, food availability, habitat features and population density for young-of-the-year Atlantic salmon (Salmo salar) in Catamaran Brook, New Brunswick, throughout their first growing season. In general, the results were consistent with the predictions of the territory-size hypothesis since the observed densities were high enough to expect competition for space while they did not exceed the maximum densities predicted. Moreover, the observed self-thinning slope of $-$1.16 was consistent with the slope predicted by the allometry of territory size established specifically for the population under study. The overall slope, however, was steeper than predicted by the allometry of metabolic rate, most likely because of a gradual decline in food abundance over the study period. The results suggest that territoriality may play a role as a mechanism of self-thinning in populations of indeterminate growers competing for food and space.

Book Individual Variability in Activity Patterns of Juvenile Atlantic Salmon Salmo Salar

Download or read book Individual Variability in Activity Patterns of Juvenile Atlantic Salmon Salmo Salar written by Cindy Breau and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: To describe the activity patterns of juvenile Atlantic salmon, I monitored the behaviour of 35 age-0+ (emerged from gravel in the spring) and eight age-1+ (emerged from gravel in the spring of the previous year) fish over an eight-week-summer field season. Active fish were visible on their home range whereas inactive fish were assumed to be sheltering. My data were consistent with the prediction of the Asset Protection Principle that larger individuals will take fewer chances in order to reduce risk of predation. Indeed, 1+ fish (larger and older) were more active at night than during the day, whereas 0+ fish were almost exclusively active during the day. In contrast to my expectations, however, daytime activity did not peak at the optimal water temperature of 17°C found in laboratory studies of other populations. Rather, the activity of 1+ fish peaked at 20.7°C, whereas the activity of 0+ fish continued to increase until 23°C and then leveled off between 23-27°C. Once individuals were active, season and light intensity were the variables that most influenced their foraging rate. There was considerable individual variability within an age-class in how fish responded to environmental variables. The causes of this individual variability and the consequences for growth deserve further study.

Book Spatial Habitat Use of Young of the year Atlantic Salmon Salmo Salar in Response to Changing Stream Discharge and Population Density

Download or read book Spatial Habitat Use of Young of the year Atlantic Salmon Salmo Salar in Response to Changing Stream Discharge and Population Density written by Christian Franz Holm and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seasonal growth patterns of wild juvenile fish

Download or read book Seasonal growth patterns of wild juvenile fish written by P J (Phil) Bacon and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Behavioural and Ecological Implications of Predation Risk in Juvenile Atlantic Salmon Salmo Salar

Download or read book Behavioural and Ecological Implications of Predation Risk in Juvenile Atlantic Salmon Salmo Salar written by Jae-Woo Kim and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the wealth of laboratory studies, the effects of local predation risk on the behaviour and ecology of a prey species under natural conditions have rarely been examined. In Chapter 1, I tested the hypothesis that juvenile Atlantic salmon (Salmo salar) use both chemical and visual information to assess predation risk under natural conditions. Both young-of-the-year (YOY) and parr salmon exhibited antipredator responses when exposed to a chemical alarm cue and exposure to alarm cues influenced their response to a visual threat. While YOY and parr differed in the type and intensity of antipredator responses, both chemical and visual cues are used in an additive manner. In Chapter 2, I tested the prediction that YOY use chemical alarm cues to assess the predation risk of alternative habitats and decide where to settle over a two-week period following emergence. In seven similar reaches of Catamaran Brook, New Brunswick, I established three contiguous sections where I manipulated the perceived predation risk by releasing alarm cues versus a stream water control. The density of YOY decreased in risky sections and increased in control and untreated buffer sections, whereas the density of parr was not affected. Clearly, YOY salmon can assess and select habitats based on the perceived level of predation risk. If one assumes that predation risk is a cost, optimality models predict that territory size will decrease with increasing predation risk. In Chapter 3, I examined whether both acute and chronic predation risk influences the territorial behaviour of YOY. When exposed to a single dose of chemical alarm cue, YOY salmon decreased the number of switches between foraging stations, but did not change their territory size or foraging rate. When exposed to chemical alarm cue over a two week period, YOY salmon reduced the size of their territories, but did not change their foraging rate or number of switches. Clearly, YOY adjusted their territorial behaviour in response to both acute and chronic increases in perceived predation risk, but in different ways. Together, my results suggest that predation risk influences not only short-term (immediate) anti-predator behaviour, but is also an important component of habitat selection and shapes territorial behaviour over longer periods.

Book In Atlantic Salmon Space Use of Potential Breeders Stabilises Population Dynamics and Shapes Sexual Selection

Download or read book In Atlantic Salmon Space Use of Potential Breeders Stabilises Population Dynamics and Shapes Sexual Selection written by Colin Bouchard and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat fragmentation and reduction in the availability of suitable habitats are significant threats to ecosystems in particularly for freshwater ones. For instance, accessibility, availability, and quality of breeding sites of Atlantic salmon, \textit{Salmo salar}, can be restricting in some rivers due to human activities and dams. Such threats may affect distribution of potential breeders because after their up-river migration, salmon females distribute within available breeding sites. Spatial distribution of females determines the spatial distribution of breeder males. Dominant males try to monopolise several females, whereas subordinate males adopt a sneaky behaviour. Access to females by males depends on the spatial distribution of females and on males' displacements within a river. The spatial distribution of females generates the spatial distribution of juveniles, aggregating them at some breeding sites. The latter aggregation of juveniles may raise the density-dependent mortality with potential consequences on population dynamics. The thesis aims to assess how space use of potential breeders, namely mature individuals able to spawn or fertilise eggs, influence population dynamics and sexual selection.I combined different approaches and different temporal and spatial scales to potential effects of space use of potential breeders. Time series of stock (deposited eggs) and of recruitment (juveniles) for the salmon population of the Nivelle River were combined with measures of spatial aggregation of nests. The effects of displacements and spatial distribution of potential breeders on their participation in reproduction were tested through inferring the sexual network of the population.I found that spatial aggregation of nests improved the recruitment variability but did not affect the average recruitment. The spatial aggregation of nests resulting from female aggregation was also linked to the number of effective breeders through a U-shaped curve. Such relationships suggested mate monopolization dependent on the spatial aggregation of females. The negative effect of the spatial isolation of females on their number of mates also suggest such mate monopolization. Then, the inferred sexual network enabled me to highlight a local social structure within the population. The latter structure and social competitors impacted the reproductive success of anadromous males. The participation of mature parr was one of the factors diminishing the sexual competition faced by anadromous males. Finally, mature parr were more mobile and moved more upstream than immature parr. Spatial behaviours of mature parr were linked to their participation in reproduction, individuals exhibiting wider home ranges had a higher probability to encounter females.Altogether my results show that space use of potential breeders affect both population dynamics and sexual selection. Then, spatial aggregation of females and of their nests can be beneficial for population dynamics as shown by combining different temporal and spatial scales. Females seemed to aggregate within the best breeding sites with a better environmental stability. The spatial distribution of females affected the ability of males to monopolise several females and participation of sneaky males. The availability of suitable good breeding habitats seemed restricting in the Nivelle, potentially due to the presence of impassable upstream dams. The lack of suitable breeding sites seemed impacting the mating system of the population and the sexual selection operating in. Some management actions to improve the quality of breeding sites and their availability could be planned.

Book Dispersal and Density dependent Growth of Early Juvenile Atlantic Salmon Salmo Salar

Download or read book Dispersal and Density dependent Growth of Early Juvenile Atlantic Salmon Salmo Salar written by Eric Brunsdon and published by . This book was released on 2015 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dispersal from nesting sites and habitat selection are essential for the fitness of young individuals and shapes the distribution, growth and persistence of populations. These processes are important to consider when releasing captive bred young individuals into the wild to restore extirpated or depleted populations. However, few studies have evaluated how manipulating densities during release affects the dispersal and growth of individuals with respect to crucial life history traits. I manipulated the density of young-of-the-year (YOY) Atlantic salmon to evaluate the effect of two stocking techniques on the life history characteristics of surviving fish. Salmon were either point-stocked (all fish released in a small area at the upstream end of a reach) or spread-stocked (fish were released evenly over the entire reach) in 14 reaches of the Boquet River, New York. I used snorkeling and electrofishing surveys to characterize the density, dispersal, growth and survival of salmon stocked via each technique. Density decreased and growth rate increased with distance downstream in point-stocking reaches, whereas density and growth were relatively constant within spread-stocking reaches. Overall, density, growth and survival did not differ between the two stocking techniques due to the greater-than-expected degree of dispersal observed in point-stocking reaches. YOY dispersed up to 1600m, with 41% moving over 200m downstream. Growth rate of individual fish was density-dependent, following the negative power curve observed in previous studies. My results provide insights into how the growth and survival of released individuals are altered via stocking techniques, ultimately shaping their distribution and persistence.

Book Within and among individual variation in metabolic rate in juvenile Atlantic salmon Salmo salar

Download or read book Within and among individual variation in metabolic rate in juvenile Atlantic salmon Salmo salar written by Karen J. Millidine and published by . This book was released on 2008 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animals may adopt a range of energy strategies to persist and perhaps prosper under various prevailing environmental conditions. For example, they may achieve similar growth by investing heavily in maintaining a high capacity food capture and processing system or by using a lower capacity system that is cheap to run but which is less effective at accruing further resources. The way that individuals within species allocate energy resources is an intriguing issue that has implications for understanding competition, population structuring and the response of populations to environmental change. Energy budgets account quantitatively for the pathways by which food energy results in variation in somatic resources and constitute an important basis for evaluating links between behaviour and aspects of performance. Atlantic salmon have been an important model for exploring relationships between growth performance, metabolic strategies and individual behaviour. Juvenile salmonid fish have been a particularly useful subject for exploring individual variation in metabolism because it has been possible to relate standard metabolic rate (SMR) to behavioural traits and lifestyle within a species. SMR correlates with dominance status, which is reflected in the ability of fish to access high value food patches and may promote faster growth under some conditions. This thesis focuses on the within- and among-individual variation in SMR and looks at how a fishÂ's external environment and social interactions can influence its SMR, and whether this variation in SMR can affect other aspects of metabolism such as feeding. Experiments were carried out to determine: (A) whether the presence of a shelter reduces SMR; this may provide an additional reason for the extent to which these fish will compete aggressively for shelters when these are limiting (Chapter 2); (B) the extent of intraspecific variation in SDA (i.e. differences in the measured parameters that are used to define SDA), and to test whether the SDA for a given meal varies as a function of individual traits such as SMR. If SMR is directly related to scope for growth, then the speed and size of the SDA response should also correlate with SMR (Chapter 3); (C) whether ventilation rate is sufficiently accurately related to metabolic rate (MR) at a range of temperatures and activities so as to allow energy expenditure to be predicted outside a respirometer (Chapter 4); and (D) how visual isolation and the presence of a conspecific can affect SMR, using the method developed in the previous chapter (Chapter 5). Access to shelter was shown to have a significant impact on SMR, producing on average a 30% increase in metabolic costs in the absence of shelter. Therefore, the presence of appropriate shelter not only reduces the risk of predation but also provides a metabolic benefit to fish that is likely to have implications for growth performance and activity budgets. Variation in SMR was shown to affect the profile of energy consumption during digestion of a meal. The peak in post-prandial oxygen consumption, the duration of elevated metabolism and the overall magnitude of SDA all increased with the size of meal consumed. However, for a given meal size, fish with a higher SMR also had a higher peak and greater magnitude of SDA, yet experienced a shorter duration over which metabolism was elevated following the meal. Intraspecific variation in SMR is thus linked to variation in digestive strategies, although the costs and benefits of a given SMR are likely to vary with resource availability and predictability. Ventilation frequency was shown to be a good correlate of MR, since MR was found to correlate strongly with VR in all fish tested, at all temperatures and the relationship was independent of causal factor. The relationship was linear, and both the slope and corresponding intercept of the regression equation were strongly dependent on the fishÂ's body weight and the test temperature. Visual measurements of VR may therefore provide a highly accurate, cheap and non-invasive method of measuring the energy consumption of fish engaged in natural behaviours. Comparing SMR of individual fish when alone with response to presence and absence of physical shelters showed that all fish exhibited a reduction in SMR when provided with an appropriate shelter. However, when grouped, there were both positive and negative group effects on SMR depending on the relative size of fish. The consequences are that, although the group effect on SMR may be small on average, at the population level it is large, of variable sign and profoundly important in terms of the overall energy budget at the individual level. This thesis therefore shows that metabolic rates can vary extensively within as well as between individuals, depending on the context, and this variation will have profound effects on overall energy budgets.

Book Centrarchid Fishes

Download or read book Centrarchid Fishes written by Steven Cooke and published by John Wiley & Sons. This book was released on 2009-09-08 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Centrarchid fishes, also known as freshwater sunfishes, include such prominent species as the Largemouth Bass, Smallmouth Bass and Bluegill. They are endemic to Eastern North America where they form part of a multi-million dollar sports fishing industry, but they have also been widely introduced around the globe by recreational anglers, in aquaculture programs and by government fisheries agencies. Centrarchid Fishes provides comprehensive coverage of all major aspects of this ecologically and commercially important group of fishes. Coverage includes diversity, ecomorphology, phylogeny and genetics, hybridization, reproduction, early life history and recruitment, feeding and growth, ecology, migrations, bioenergetics, physiology, diseases, aquaculture, fisheries management and conservation. Chapters have been written by well-known and respected scientists and the whole has been drawn together by Professors Cooke and Philipp, themselves extremely well respected in the area of fisheries management and conservation. Centrarchid Fishes is an essential purchase for all fish biologists, ecologists, fisheries managers and fish farm personnel who work with centrarchid species across the globe.

Book Atlantic Salmon Ecology

Download or read book Atlantic Salmon Ecology written by Øystein Aas and published by John Wiley & Sons. This book was released on 2010-10-18 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Atlantic salmon is one of the most prized and exploited species worldwide, being at the centre of a massive sports fishing industry and increasingly as the major farmed species in many countries worldwide. Atlantic Salmon Ecology is a landmark publication, both scientifically important and visually attractive. Comprehensively covering all major aspects of the relationship of the Atlantic salmon with its environment, chapters include details of migration and dispersal, reproduction, habitat requirements, feeding, growth rates, competition, predation, parasitsm, population dynamics, effects of landscape use, hydro power development, climate change, and exploitation. The book closes with a summary and look at possible future research directions. Backed by the Norwegian Research Council and with editors and contributors widely known and respected, Atlantic Salmon Ecology is an essential purchase for all those working with this species, including fisheries scientists and managers, fish biologists, ecologists, physiologists, environmental biologists and aquatic scientists, fish and wildlife department personnel and regulatory bodies. Libraries in all universities and research establishments where these subjects are studied and taught should have copies of this important publication. Comprehensive and up-to-date coverage of Atlantic Salmon Atlantic Salmon is one of the world's most commercially important species Backed by the Norwegian Research Council Experienced editor and internationally respected contributors

Book Selective Breeding in Aquaculture an Introduction

Download or read book Selective Breeding in Aquaculture an Introduction written by Trygve Gjedrem and published by Springer Science & Business Media. This book was released on 2010-03-17 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The foundation of quantitative genetics theory was developed during the last century and facilitated many successful breeding programs for cultivated plants and t- restrial livestock. The results have been almost universally impressive, and today nearly all agricultural production utilises genetically improved seed and animals. The aquaculture industry can learn a great deal from these experiences, because the basic theory behind selective breeding is the same for all species. The ?rst published selection experiments in aquaculture started in 1920 s to improve disease resistance in ?sh, but it was not before the 1970 s that the ?rst family based breeding program was initiated for Atlantic salmon in Norway by AKVAFORSK. Unfortunately, the subsequent implementation of selective breeding on a wider scale in aquaculture has been slow, and despite the dramatic gains that have been demonstrated in a number of species, less than 10% of world aquaculture production is currently based on improved stocks. For the long-term sustainability of aquaculture production, there is an urgent need to develop and implement e- cient breeding programs for all species under commercial production. The ability for aquaculture to successfully meet the demands of an ever increasing human p- ulation, will rely on genetically improved stocks that utilise feed, water and land resources in an ef?cient way. Technological advances like genome sequences of aquaculture species, and advanced molecular methods means that there are new and exciting prospects for building on these well-established methods into the future.