Environmental influences of life history strategies in partial anadromous brown trout (Salmo trutta, Salmonidae)

• Published in: Fish and Fisheries
• Main Authors: Nevoux, Marie, Finstad, Bengt, Davidsen, Jan Grimsrud, Finlay, Ross, Josset, Quentin, Poole, Russell, Hojesjo, Johan, Aarestrup, Kim, Persson, Lo, Tolyanen, Oula, Jonsson, Bror
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Norwegian Institute for Nature Research (NINA), Department of Natural History, University Museum, Marine Institute, Direction de la Recherche, de l’Expertise et des données, Agence Française pour la Biodiversité (AFB), Department of Biological and Environmental Sciences, National Institute of Aquatic Resources, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences = Sveriges lantbruksuniversitet (SLU), The Water Protection Association of the River Vantaa and Helsinki Region, Department of Landscape Ecology
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: freshwater resident; habitat; migration; partial anadromy; Salmonidae; sex ratio; charr salvelinus-alpinus; wild atlantic salmon; lice; lepeophtheirus-salmonis; alternative mating tactics; sexual size; dimorphism; fresh-water resident; nonanadromous oncorhynchus-mykiss; sea-trout; climate-change; arctic charr; [SDV]Life Sciences [q-bio]; Arctic; Arctic charr; Atlantic salmon; Climate change; Global warming; Salvelinus alpinus
• Online Access: https://hal.science/hal-02501450; https://doi.org/10.1111/faf.12396

This paper reviews the life history of brown trout and factors influencing decisions to migrate. Decisions that maximize fitness appear dependent on size at age. In partly anadromous populations, individuals that attain maturity at the parr stage typically become freshwater resident. For individual fish, the life history is not genetically fixed and can be modified by the previous growth history and energetic state in early life. This phenotypic plasticity may be influenced by epigenetic modifications of the genome. Thus, factors influencing survival and growth determine life-history decisions. These are intra- and interspecific competition, feeding and shelter opportunities in freshwater and salt water, temperature in alternative habitats and flow conditions in running water. Male trout exhibit alternative mating strategies and can spawn as a subordinate sneaker or a dominant competitor. Females do not exhibit alternative mating behaviour. The relationship between growth, size and reproductive success differs between sexes in that females exhibit a higher tendency to migrate than males. Southern populations are sensitive to global warming. In addition, fisheries, aquaculture with increased spreading of salmon lice, introduction of new species, weirs and river regulation, poor water quality and coastal developments all threaten trout populations. The paper summarizes life-history data from six populations across Europe and ends by presenting new research questions and directions for future research.