Heritable morphological differentiation in salmonids from two distinct stream types

Abstract

We tested for phenotype‐to‐habitat associations in brown trout Salmo trutta populations from two ecologically different habitat types; i.e., groundwater and surface‐water‐fed streams. Additionally, we raised captive offspring from two such populations under standardised conditions to test whether potential phenotypic differentiation would be passed on to offspring. We found analogous differentiation by habitat in multiple wild populations. Some of these morphological differences were at least partially inherited by offspring. We suggest that this could have implications for both scientists and fisheries authorities studying or managing trout populations.

Is shape in the eye of the beholder? Assessing landmarking error in geometric morphometric analyses on live fish

“…The landmark positions chosen were those commonly used in studies on salmonids ( e.g. , Boulding et al, 2008 ; Muir, Vecsei & Krueger, 2012 ; Simonsen et al, 2017 ; Goerig et al, 2019 ; Dermond, Sperlich & Brodersen, 2019 ). In addition, the first ten fish for each river, after using the randomly order specimens function in tpsUtil, were consecutively landmarked a further two times ( i.e., three times in total) by each operator to evaluate the intra-operator consistency in digitisation.…”

Is shape in the eye of the beholder? Assessing landmarking error in geometric morphometric analyses on live fish

“…1). Landmark positions were chosen according to the ones commonly used in studies on salmonids (e.g., Boulding et al, 2008; Muir, Vecsei & Krueger, 2012; Simonsen et al, 2017; Goerig et al, 2019; Dermond, Sperlich & Brodersen, 2019). In addition, 20 fish from both rivers were randomly selected from the dataset and consecutively landmarked a further two times (i.e.…”

“…The three points along the curve were then converted to fixed landmarks using the Append tps Curve to landmarks function. The landmark positions chosen were those commonly used in studies on salmonids (e.g., Boulding et al, 2008; Muir, Vecsei & Krueger, 2012; Simonsen et al, 2017; Goerig et al, 2019; Dermond, Sperlich & Brodersen, 2019). In addition, the first ten fish for each river, after using the randomly order specimens function in tpsUtil, were consecutively landmarked a further two times (i.e.…”

Conspecific migration and environmental setting determine parasite infracommunities of non-migratory individual fish

“…Thus, their parasite community should reflect the locally acquired species. Fish were euthanized using a high concentration of MS222 (Tricaine Methane-Sulphonate) (Popovic et al ., 2012 ; Dermond et al ., 2019 b ). Then, all fish were weighed and measured before freezing at −20°C until parasitological examination.…”

“…Abiotic processes like the unidirectional water flow in streams can structure free-living and parasite populations and communities by favouring a downstream dispersion of small organisms, thus increasing their concentration downstream (Blasco-Costa et al ., 2013 ; Paterson et al ., 2018 ; Tonkin et al ., 2018 ). Furthermore, the environmental conditions of streams may affect both phenotype and foraging ecology of the resident hosts (Dermond et al ., 2018 , 2019 a , 2019 b ). Hence, environmental conditions that affect the hosts directly or indirectly will have a cascading effect on the prevalence and abundance of parasites, and on the diversity of parasites infecting them (MacKenzie et al ., 1995 ; Marcogliese and Cone, 1997 ).…”