A brain and a head for a different habitat: size variation in four morphs of Arctic charr (Salvelinus alpinus (L.)) in a deep oligotrophic lake ...

• Main Authors: Peris, Ana, Devineau, Olivier, Præbel, Kim, Kahilainen, Kimmo K., Østbye, Kjartan
• Format: Dataset
• Language: English
• Published: Dryad 2020
• Subjects: Arctic; Norway; Arctic charr; Salvelinus alpinus
• Online Access: https://dx.doi.org/10.5061/dryad.15dv41nvt; https://datadryad.org/stash/dataset/doi:10.5061/dryad.15dv41nvt

Adaptive radiation is the diversification of species to different ecological niches and has repeatedly occurred in different salmonid fish of postglacial lakes. In Lake Tinnsjøen, one of the largest and deepest lakes in Norway, the salmonid fish, Arctic charr (Salvelinus alpinus (L.)), has likely radiated within 9700 years after deglaciation into ecologically and genetically segregated Piscivore, Planktivore, Dwarf and Abyssal morphs in the pelagial, littoral, shallow-moderate profundal and deep-profundal habitats. We compared trait variation in the head shape, the eye and olfactory organs, as well as the volumes of five brain regions of these four Arctic charr morphs. We hypothesised that specific habitat characteristics have promoted divergent body, head and brain sizes related to utilized depth differing in environmental constraints (e.g. light, oxygen, pressure, temperature and food quality). The most important ecomorphological variables differentiating morphs were body length, habitat, optic tectum and ... : We sampled fish using gillnets, traps and baited anchored longlines in August-October 2013 (Østbye et al., 2020). We sampled in four habitats; (i) the pelagial (setting gillnets positioned more than 50 m from shore and 20-30 m depth in midwater using a 12-panel multimesh Nordic series with mesh sizes in this order of 43, 19.5, 10.0, 55.0, 12.5, 24, 15.5, 35.0, 29.0, 6.3, 5.0 and 10.0 mm and Jensen floating series with mesh size of 13.5, 16.5, 19.5, 22.5, 26.0, 29.0, 35.0, 39.0, 45.0 and 52.0 mm), (ii) the littoral (gillnets within 20 m from the shore using Nordic and Jensen littoral net series), (iii) the shallow-moderate profundal (Jensen littoral net series, traps and hook-line between 20-150 m depth), and (iv) the deep profundal (setting traps > 150 m depth and > 100 m from the shoreline using longlines of 220m long and 3 to 4 mm line with 180 hooks; see more detailed information in Østbye et al., (2020)). In the field, we assigned each individual to one of the four morphs (called field-assigned ...