With partial support from the Moore Foundation, researchers at the University of Washington and University of Oregon have discovered that Dolly Varden trout remain in freshwater streams rather than returning to marine waters after they reach a certain size--relying in part on a symbiotic relationship with their sockeye salmon cousins.

The study, published in the journal Ecology, "shows that Dolly Varden, once they reach about 12 inches in length, can retire permanently from going to sea. They rely on digestive organs that can massively expand and contract and a unique relationship with sockeye salmon."

Read the Ecology study, "Beyond dichotomous life histories in partially migrating populations: cessation of anadromy in a long-lived fish," here.

Read the UW Today story, "Alaskan trout choose early retirement over risky ocean-going career," here.