Response of a marine population of three‐spine sticklebacks (Gasterosteus aculeatus) to salinity stress

Abstract

Three‐spine sticklebacks are euryhaline fish that can live in marine and limnic environments. Populations of this species have evolved the ability to invade freshwater and become landlocked many times independently in Europe, Asia, and North America. They represent an excellent model for studying adaptive constraints leading to parallel evolution. We are interested in how salinity tolerance as a physiological trait evolved during such parallel evolution in plasma‐hyper vs. plasma‐hyposmotic environments. Thus, we are characterizing the osmotolerance of different stickleback populations starting with an ancestral marine population established at Bodega Harbor, CA. Osmotolerance in these fish was assessed by exposing them to gradual salinity change (3 ppt/ day) and monitoring physiological parameters including ventilation rate and behavioral parameters (feeding, swimming behavior). We also collected osmoregulatory tissues from animals gradually acclimated to different salinities ranging from FW to 70 ppt and performed molecular phenotyping of these tissues using proteomics. The resulting data provide a comprehensive physiological baseline for comparing salinity stress responses of this marine population to that of land‐locked limnic populations.