The first brown trout were stocked in Tierra del Fuego by John Goodall in 1935. Shipped from Puerto Montt in Chile, 60,000 "Salmo Trutta" eggs survived the arduous journey, to be planted on the Candelaria and McLennan Rivers, both tributaries of the Rio Grande. These fish eventually found their way to the sea, possibly attracted by the rich nourishment of the estuary. These sea-run brown trout now complete the yearly migratory cycle of salmonids, spawning during the summer months in freshwater.

Salmo Trutta remain in the river for a period of time which ranges between 1 and 4 years until their first migration to the sea, where they will feed and grow for about 6 months before their first return to freshwater, weighing approximately 6 lbs.  A trout which has completed four cycles of returning to freshwater can weigh over 20 lbs.  The frequency with which they return to freshwater is also an indicator that the fish face very few threats whilst also providing a very real example of the benefits of Catch and Release.