SEA RUN BROWN: Argentina - Tierra del Fuego

The Rio Grande  in Tierra del Fuego, Argentina flows west from the Andes to the Atlantic through 70 km of steppe.   In 1935, John Goodall stocked 60,000 Chilean salmo trutta eggs in 2 tributaries of the Rio Grande.  Attracted by the nutrient rich waters of the estuary, these fish found their way to the sea and began a yearly migration like Pacific and Atlantic Salmons.

Young Brown Trout will spend an average of 2 years in the river before their first migration to the sea where they’ll spend 6 months before returning to the river with an average weight of 6 lbs.

Brown Trout that have spawned 4 times can weigh over 20 lbs and some fish have been known to complete the cycle 6 times.  Studies show that the Sea Run Browns in Tierra del Fuego’s Rio Grande are about 17% heavier than other sea trout of the same length.  They experience very little predation and thus have a higher frequency of return than other andronomous salmonids.  The fly fishing lodges and ranches along the Rio Grande have all vowed to a strict Catch and Release policy which is also a major factor in the high frequency of return.

In 2008, the population of Sea Run Browns in the Rio Grande was estimated to be about 75,500 adult fish.  Average daily catches are 3-6 fish per rod. Proficient anglers and veterans of the Rio Grande tend to do slightly better.  The key to success is to adapt your fly fishing technique.  Sea Run Browns are rather moody fish and will strike when the fly is presented well, at the right time and in the right spot.  Water levels change from week to week on the Rio Grande and your guide will instruct you on what depth the fly should be and how to present it.  However, the presentation that worked in the morning may not work in the evening requiring the angler to change his tactics.  If a fly that is moving evenly and slowly still does not produce a strike, considering modifying the depth, area of the pool or fly pattern.

Fly placement is also a factor as Sea Runs tend to lie near the cut banks during the middle of the day, requiring the angler to reach the far bank with his fly.  Like other andronomous salmonids, Sea Run Browns generally move up river at night meaning they may congregate at the head of the pool in the evening and at the tail of the pool in the morning.  On overcast days the fish could be found in the middle of the pools.

Peak season for fly fishing in Tierra del Fuego is mid February to Mid March, however, great fishing can be had all season. Seriously.  The early season of December until mid January is when the freshest, brightest, and most energetic fish of the season are caught.  The lower section of the river, such as near Villa Maria Lodge and Estancia Maria Behety is a good place to be this time of the year. Anglers at these lodges have had 30 fish days in December.  With the water levels being higher, double handed rods are even more useful in the early season.

April is the other shoulder season that can be equally exciting and productive as mid season.  At this time, all the fish that are going to return are now in the river.  These tend to be more spectacular looking with their orange and red fall colors, but more importantly, they tend to be bigger.  The water levels are at their lowest and the greatest numbers of fish are now more concentrated.  The strong Tierra del Fuego winds are also significantly diminished.  As an additional bonus, we sometimes offer reduced rates for some March and April weeks.