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  • Ahlgren, Johan, et al. (författare)
  • Individual boldness is linked to protective shell shape in aquatic snails
  • 2015
  • Ingår i: Biology Letters. - London : Royal society. - 1744-9561 .- 1744-957X. ; 11:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The existence of consistent individual differences in behaviour ('animal personality') has been well documented in recent years. However, how such individual variation in behaviour is maintained over evolutionary time is an ongoing conundrum. A well-studied axis of animal personality is individual variation along a bold-shy continuum, where individuals differ consistently in their propensity to take risks. A predation-risk cost to boldness is often assumed, but also that the reproductive benefits associated with boldness lead to equivalent fitness outcomes between bold and shy individuals over a lifetime. However, an alternative or complementary explanation may be that bold individuals phenotypically compensate for their risky lifestyle to reduce predation costs, for instance by investing in more pronounced morphological defences. Here, we investigate the 'phenotypic compensation' hypothesis, i.e. that bold individuals exhibit more pronounced anti-predator defences than shy individuals, by relating shell shape in the aquatic snail Radix balthica to an index of individual boldness. Our analyses find a strong relationship between risk-taking propensity and shell shape in this species, with bolder individuals exhibiting a more defended shell shape than shy individuals. We suggest that this supports the 'phenotypic compensation' hypothesis and sheds light on a previously poorly studied mechanism to promote the maintenance of personality variation among animals.
  • Björnerås, Caroline, et al. (författare)
  • Inland blue holes of The Bahamas - chemistry and biology in a unique aquatic environment
  • 2020
  • Ingår i: Fundamental and Applied Limnology. - : Schweizerbart science publishers. - 1863-9135. ; 194:2, s. 95-106
  • Tidskriftsartikel (refereegranskat)abstract
    • While lake systems in temperate regions have been extensively studied, tropical and subtropical systems have received less attention. Here, we describe the water chemistry and biota of ten inland blue holes on Andros Island, The Bahamas, representative of the morphological, abiotic, and biotic variation among Androsian inland blue holes. The majority of the studied blue holes were vertically stratified with oxic freshwater overlying anoxic saline groundwater of marine origin. Water chemistry (e.g. total phosphorus and nitrogen) in shallow waters was similar among blue holes, while turbidity and water color varied. Presence of hydrogen sulfide and reduced iron in and below the halocline indicate reducing conditions in all stratified blue holes. The biota above the halocline was also similar among blue holes with a few taxa dominating the phytoplankton community, and the zooplankton community consisting of copepods and rotifers. The Bahamas mosquitofish (Gambusia hubbsi) was present in all investigated blue holes, often accompanied by other small planktivorous fish, while the piscivorous bigmouth sleeper (Gobiomorus donnitor) was only present in some of the blue holes. Our field study reinforces that inland blue holes are highly interesting for biogeochemical research, and provide naturally replicated systems for evolutionary studies.
  • Blake, Chelsea A., et al. (författare)
  • Conspecific boldness and predator species determine predation-risk consequences of prey personality
  • 2018
  • Ingår i: Behavioral Ecology and Sociobiology. - : Springer-Verlag New York. - 0340-5443 .- 1432-0762. ; 72:8, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: Individual variation in the behavior of prey can influence predation risk in complex ways. We ran individual roach (Rutilus rutilus), a common freshwater fish, through a standard refuge emergence protocol to characterize their boldness, a key animal personality trait. We then paired a bold and a shy roach and exposed the pair to one of two predator species that have contrasting hunting modes to ascertain how personality traits shaped their survival during predator encounters. When a paired bold and shy prey fish interacted with a perch predator (active foraging mode), bold and shy prey were consumed in almost equal numbers. However, pike predators (ambush foraging mode) selectively consumed more shy prey, and prey body size and boldness score both contributed significantly to which prey fish was eaten. Our findings support the idea that multiple predators with different foraging modes, and hence differential selection on prey personality, could contribute to maintaining variation in personality in prey populations. Furthermore, for social species, including shoaling fish, the ultimate consequences of an individual’s personality may depend upon the personality of its nearby conspecifics. Significance statement: Animals of the same species often look similar, but individuals show differences in their behavior that can have important consequences, for instance when these individuals interact with predators. The common roach is a freshwater fish that shows inter-individual variation in its propensity to take risks, a key personality trait often termed boldness. Variation in boldness may affect the outcome when roach interact with predators, i.e., if they get eaten or survive. However, we found the impact of roachs’ personality type depends on what species of predatory fish they face. When we put a shy and a bold roach together with predatory perch, the roachs’ personality did not significantly affect which individual was eaten. But when the predator was a pike, the predators selectively ate more shy roach, and the likelihood an individual would be eaten depended on their body size.
  • Brodersen, Jakob, et al. (författare)
  • Interplay between temperature, fish partial migration and trophic dynamics
  • 2011
  • Ingår i: Oikos. - : Wiley-Blackwell. - 1600-0706 .- 0030-1299. ; 120:12, s. 1838-1846
  • Tidskriftsartikel (refereegranskat)abstract
    • Whereas many studies have addressed the mechanisms driving partial migration, few have focused on the consequences of partial migration on trophic dynamics, and integrated studies combining the two approaches are virtually nonexistent. Here we show that temperature affects seasonal partial migration of cyprinid fish from lakes to predation refuges in streams during winter and that this migration in combination with temperature affects the characteristics and phenology of lower trophic levels in the lake ecosystem. Specifically, our six-year study showed that the proportion of fish migrating was positively related to lake temperature during the pre-migration growth period, i.e. during summer. Migration from the lake occurred later when autumn water temperatures were high, and timing of return migration to the lake occurred earlier at higher spring water temperatures. Moreover, the winter mean size of zooplankton in the lake increased with the proportion of fish being away from the lake, likely as a consequence of decreased predation pressure. Peak biomass of phytoplankton in spring occurred earlier at higher spring water temperatures and with less fish being away from the lake. Accordingly, peak zooplankton biomass occurred earlier at higher spring water temperature, but relatively later if less fish were away from the lake. Hence, the time between phyto- and zooplankton peaks depended only on the amount of fish being away from the lake, and not on temperature. The intensity of fish migration thereby had a major effect on plankton spring dynamics. These results significantly contribute to our understanding of the interplay between partial migration and trophic dynamics, and suggest that ongoing climate change may significantly affect such dynamics.
  • Brönmark, Christer, et al. (författare)
  • There and back again: migration in freshwater fishes
  • 2014
  • Ingår i: Canadian Journal of Zoology. - Ottawa : National Research Council Canada. - 1480-3283 .- 0008-4301. ; 92:6, s. 467-479
  • Forskningsöversikt (refereegranskat)abstract
    • Animal migration is an amazing phenomenon that has fascinated humans for long. Many freshwater fishes also show remarkable migrations, whereof the spectacular mass migrations of salmonids from the spawning streams are the most well known and well studied. However, recent studies have shown that migration occurs in a range of freshwater fish taxa from many different habitats. In this review we focus on the causes and consequences of migration in freshwater fishes. We start with an introduction of concepts and categories of migration, and then address the evolutionary causes that drive individuals to make these migratory journeys. The basis for the decision of an individual fish to migrate or stay resident is an evaluation of the costs and benefits of different strategies to maximize its lifetime reproductive effort. We provide examples by discussing our own work on the causes behind seasonal migration in a cyprinid fish, roach (Rutilus rutilus (L., 1758)), within this framework. We then highlight different adaptations that allow fish to migrate over sometimes vast journeys across space, including capacity for orientation, osmoregulation, and efficient energy expenditure. Following this we consider the consequences of migration in freshwater fish from ecological, evolutionary, and conservation perspectives, and finally, we detail some of the recent developments in the methodologies used to collect data on fish migration and how these could be used in future research.
  • Chapman, Ben, et al. (författare)
  • Partial migration in fishes: causes and consequences.
  • 2012
  • Ingår i: Journal of Fish Biology. - : Wiley-Blackwell. - 0022-1112 .- 1095-8649. ; 81:2, s. 456-478
  • Tidskriftsartikel (refereegranskat)abstract
    • Partial migration, where only some individuals from a population migrate, has been widely reported in a diverse range of animals. In this paper, what is known about the causes and consequences of partial migration in fishes is reviewed. Firstly, the ultimate and proximate drivers of partial migration are reflected upon: what ecological factors can shape the evolution of migratory dimorphism? How is partial migration maintained over evolutionary timescales? What proximate mechanisms determine whether an individual is migratory or remains resident? Following this, the consequences of partial migration are considered, in an ecological and evolutionary context, and also in an applied sense. Here it is argued that understanding the concept of partial migration is crucial for fisheries and ecosystem managers, and can provide information for conservation strategies. The review concludes with a reflection on the future opportunities in this field, and the avenues of research that are likely to be fruitful to shed light on the enduring puzzle of partial migration in fishes.
  • Chapman, Ben, et al. (författare)
  • Partial migration in fishes: definitions, methodologies and taxonomic distribution.
  • 2012
  • Ingår i: Journal of Fish Biology. - : Wiley-Blackwell. - 0022-1112 .- 1095-8649. ; 81:2, s. 479-499
  • Tidskriftsartikel (refereegranskat)abstract
    • Partial migration, where populations are composed of both migratory and resident individuals, is extremely widespread across the animal kingdom. Researchers studying fish movements have long recognized that many fishes are partial migrants, however, no detailed taxonomic review has ever been published. In addition, previous work and synthesis has been hampered by a varied lexicon associated with this phenomenon in fishes. In this review, definitions and important concepts in partial migration research are discussed, and a classification system of the different forms of partial migration in fishes introduced. Next, a detailed taxonomic overview of partial migration in this group is considered. Finally, methodological approaches that ichthyologists can use to study this fascinating phenomenon are reviewed. Partial migration is more widespread amongst fishes than previously thought, and given the array of techniques available to fish biologists to study migratory variation the future of the field looks promising.
  • Chapman, Ben, et al. (författare)
  • Shape up or ship out: migratory behaviour predicts morphology across spatial scale in a freshwater fish.
  • 2015
  • Ingår i: Journal of Animal Ecology. - : Federation of European Neuroscience Societies and Blackwell Publishing Ltd. - 1365-2656 .- 0021-8790. ; 84:5, s. 1187-1193
  • Tidskriftsartikel (refereegranskat)abstract
    • 1.Migration is a widespread phenomenon, with powerful ecological and evolutionary consequences. Morphological adaptations to reduce the energetic costs associated with migratory transport are commonly documented for migratory species. However few studies have investigated whether variation in body morphology can be explained by variation in migratory strategy within a species. 2.We address this question in roach Rutilus rutilus, a partially migratory freshwater fish that migrates from lakes into streams during winter. We both compare body shape between populations that differ in migratory opportunity (open versus closed lakes), and between individuals from a single population that vary in migratory propensity (migrants and residents from a partially migratory population). Following hydrodynamic theory, we posit that migrants should have a more shallow body depth, to reduce the costs associated with migrating into streams with higher flow conditions than the lakes the residents occupy all year round. 3.We find evidence both across and within-populations to support our prediction, with individuals from open lakes and migrants from the partially migratory population having a more slender, shallow-bodied morphology than fish from closed lakes and all-year residents. 4.Our data suggest that a shallow body morphology is beneficial to migratory individuals and our study is one of the first to link migratory strategy and intraspecific variation in body shape. This article is protected by copyright. All rights reserved.
  • Greenberg, L A, et al. (författare)
  • Effects of kinship on growth and movements of brown trout in field enclosures
  • 2002
  • Ingår i: Ecology of Freshwater Fish. - : Wiley-Blackwell. - 0906-6691 .- 1600-0633. ; 11:4, s. 251-259
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of kinship on growth and use of space by individually PIT-tagged 1+ brown trout was studied for 11 weeks in eight stream enclosures. Each enclosure consisted of two sections, separated by a region containing PIT-detecting antennae, which enabled us to measure use of sections by all individuals. Two types of sibling groups were tested, a single sibling group, F1, consisting of four individuals that were reared together in hatchery tank 'a' (F1a) plus four additional siblings of the same family but raised in hatchery tank 'b' (F1b), and a mixed sibling group, consisting of four F1a individuals plus four siblings from a second family, F2. Based on kin theory and earlier laboratory studies, we expected that growth of the F1a individuals in the single sibling group to be greater than that of F1a individuals in the mixed family sibling group, but instead we found just the opposite. The variance of growth did not differ between treatments. Nor was there a difference in time F1a individuals spent together when they were in mixed versus single sibling groups. We did find that F1a individuals changed habitat more frequently than F2 individuals in the mixed sibling group but less frequently than F1b in the single sibling groups. Thus, our predictions based on kin theory for growth and behavior of brown trout were not supported by our data, and we suggest that the role of kin recognition for the ecology of salmonids deserves further attention.
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