DOI: 10.5061/dryad.280gb5mq4
title: Morphological evolution reduces downstream displacement in juvenile landlocked salmon

description: Severe flooding often leads to downstream displacement of aquatic animals.
 Despite this, many salmonid populations persist in habitats located
 upstream of tall barriers, such as artificial check dams and/or natural
 waterfalls, that completely block fishes from returning to the upstream
 areas after flooding. The evolution of such populations may be affected by
 spatial sorting due to differential rates of downstream displacement. This
 study examined whether a morphological trait (increased body depth) that
 allows individuals to better maintain their position during flooding has
 evolved in juvenile amago salmon Oncorhynchus masou ishikawae inhabiting
 above-barrier habitats in two rivers. In both rivers, juveniles collected
 at the stations with multiple downstream barriers had deeper bodies than
 those collected at other stations. Similar differences were found in
 juveniles reared in a common-garden experiment. Field experiments with
 natural flooding also indicated that deep bodies help juveniles resist
 downstream displacement. These results consistently suggest that juveniles
 in some above-barrier habitats have evolved deep bodies to resist
 downstream displacement due to flooding. Our study is the first to show
 the evolutionary outcomes of passive spatial sorting during severe climate
 events.
description: Data for Morphological evolution reduces downstream displacement
 in juvenile landlocked salmon Yamada and Wada, Evolution 2021.
 These files contain all data for the field survey, field
 experiment, and common environment experiment. <br>Data for the
 field survey and common garden experiment are divided into two data files
 (i.e., Koza River data and Hirai River data).
 Explanation for the variables:  Release day
 (File for the field experiment):<br>  Release group for the field
 experiment ("8-Jun" and "20-Jun"corresponds to the
 first and second release group, respectively).
  Retention status (File for the field experiment):<br> 
 Juveniles were assigned a retention status of 1 if they were recaptured
 above the first check dam, and a retention status of 0 if they were
 recaptured further downstream.   Ascent status (File
 for the field experiment):<br>  Juveniles were assigned an ascent
 status of 1 if they were recaptured upstream of the uppermost step, and an
 ascent status of 0 if they were recaptured further downstream.
  Cage ID (Files for the common garden experiment):<br>  ID
 of the cage in which the juveniles were raised.
  Habitat group (Files for the field survey and common garden
 experiment):<br>  Attributes of each study station regarding
 barriers.                                           
  Station (Files for the field survey and common garden
 experiment):<br>  Name of each study station.
  PC1 (Files for the field survey, field experiment, and common
 garden experiment):<br>  PC1 obtained by principal component
 analysis of the log transformed body depth measurements for all data
 (i.e., the field survey, field experiment, and common garden
 experiment).<br> <br> PC1 residual (Files for the field
 survey, field experiment, and common garden experiment):<br> 
 Residuals calculated from the predicted values of linear regression models
 and the −PC1 values.<br>  <br> Caudal peduncle depth-1 (Files
 for the field survey, field experiment, and common garden
 experiment):<br>  Measurement values of the caudal peduncle depth at
 the posterior end of the adipose fin.  Caudal peduncle
 depth-2 (Files for the field survey, field experiment, and common garden
 experiment):<br>  Measurement values of the caudal peduncle depth
 from the posterior end of the anal fin to the anterior end of the adipose
 fin.  Body depth-1 (Files for the field survey, field
 experiment, and common garden experiment):<br>  Measurement values
 of the body depth from the lateral line to the anterior end of the dorsal
 fin.  Body depth-2 (Files for the field survey, field
 experiment, and common garden experiment):<br>  Measurement values
 of the body depth at the anterior end of the anal
 fin.<br> <br> Fork length (Files for the field survey, field
 experiment, and common garden experiment):<br>  Measurement values
 of the fork length.