The Dolly Varden, a species of char common in southeast Alaska, adjust their migrations to keep feasting on salmon eggs even as the timing of salmon spawning varies, according to a recent study.
The Dolly Varden’s secret appears to be that instead of taking its migration cues from environmental variables such as water temperature or streamflow, the species cues directly off the presence of salmon the Dolly Varden depend on for food, the study found.
Dolly Varden get most of their energy over the course of each year by gorging themselves on salmon eggs. The Dolly Varden must follow salmon migrations closely to take full advantage of this annual salmon egg bonanza.
Previous research by the University of Alaska and NOAA Fisheries’ Alaska Fisheries Science Center in southeast Alaska’s Auke Creek has shown that pink and coho salmon now migrate to their spawning grounds 10 to 17 days earlier while sockeye salmon migrate eight days earlier.
Despite a shifting climate, seagoing Dolly Varden in Auke Creek have accurately adjusted their annual migrations from the ocean back to freshwater to coincide with salmon spawning, according to the new research that includes coauthors from the University of Wyoming and NOAA Fisheries’ Northwest Fisheries Science Center.
source: NOAA Northwest Fisheries Science Center