Differences in brain morphology of brown trout across stream, lake, and hatchery environments. Issue 3 (8th March 2022)

• Record Type: Journal Article
• Authors: Závorka, Libor; Koene, J. Peter; Armstrong, Tiffany A.; Fehlinger, Lena; Adams, Colin E.
• Is Part Of: Ecology and evolution. Volume 12:Issue 3(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-08
• Subjects: animal cognition -- hatchery environment -- intraspecific variably -- Omega‐3 long‐chain fatty acids -- trophic interactions; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.8684
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: It has been suggested that a trade‐off between cognitive capacity and developmental costs may drive brain size and morphology across fish species, but this pattern is less well explored at the intraspecific level. Physical habitat complexity has been proposed as a key selection pressure on cognitive capacity that shapes brain morphology of fishes. In this study, we compared brain morphology of brown trout, Salmo trutta, from stream, lake, and hatchery environments, which generally differ in physical complexity ranging from low habitat complexity in the hatchery to high habitat complexity in streams and intermediate complexity in lakes. We found that brain size, and the size of optic tectum and telencephalon differed across the three habitats, both being largest in lake fish with a tendency to be smaller in the stream compared to hatchery fish. Therefore, our findings do not support the hypothesis that in brown trout the volume of brain and its regions important for navigation and decision‐making increases in physically complex habitats. We suggest that the observed differences in brain size might be associated with diet quality and habitat‐specific behavioral adaptations rather than physical habitat complexity. Abstract : The trade‐off between the information‐processing capacity and the developmental costs is suggested to drive brain morphology across fish species. We compared brain morphology of brown trout from three habitats differing in their physical complexity and quality of available diet. The overall brain size and size of telencephalon differed across the habitats, and the differences appeared to associate with diet quality and habitat‐specific behavioral adaptations rather than physical habitat complexity.