Every aspect of the Río Santa Cruz is big – the river, the current, the tides, the wind, the surrounding landscape, the amount of wildlife, and perhaps most importantly for fly fishermen – the fish. Harboring the only known run of Atlantic steelhead in the world, the massive Río Santa Cruz is a nascent fishery only recently beginning to draw international attention within the steelheading community. Not until the early 90’s were the first attempts made to catch these fish on fly tackle, and in a river of such size and isolation, much of its water has yet to see a fly. But in as many ways as its mystique attracts fishermen and captivates their imaginations, it also deters them. But the allure of an exotic run of extremely well-proportioned and hard fighting steelhead, set in an equally exotic location, has nonetheless compelled determined fishermen to brave the elements. Fortunately, they unlocked many of the river’s secrets and have proven that catching Santa Cruz steelhead is anything but impossible.

Fishing Program

 At Los Plateados Lodge the fishing hours are scheduled according to the best angling opportunity. There are four different zones with 30 named pools.  Using trucks and powered boats to access the river guests will rotate among the different zones to fish the most productive pools and runs.  A typical day at Los Plateados starts early and ends late.  Anglers head to the river following an early breakfast, fish until mid-day, take in a riverside lunch, and fish into the evening hours before returning to the lodge for a late dinner. All of the guides speak good English and are talented instructors, casters and anglers. Guides will rotate among paired anglers, giving guests the opportunity to fish with multiple guides throughout their stay.  Depending on the particular pool or water conditions anglers will find themselves swinging flies in a traditional manner or more likely imparting motion to the fly by stripping in line.

The Origins of the Santa Cruz Steelhead

The exact origin of Santa Cruz steelhead remains unclear, but genetic testing has strongly linked them to a strain of rainbow trout taken from California’s McCloud River and widely distributed throughout the region shortly after the turn of the 20th century. What has developed since is nothing short of amazing. As well as claiming the only Atlantic run of steelhead in the world, the Santa Cruz also boasts the only known population of introduced rainbow trout to have developed a self-sustaining anadromous population. Whether this anadromy manifested itself as an environmental response to the infertile glacial waters of the Santa Cruz, or was simply inherited from the parental stock remains unclear, but either way, the results have been impressive. By the late 60’s, rumors began to surface telling of fishermen catching large, incredibly hard-fighting chrome specimens while fishing for Robalo (a sucker-like fish) in the estuary.  It wasn’t until 1982, however, when the first veritable steelhead was captured and confirmed. Biologists are only recently beginning to rigorously study the complexities of this unique fish. Amazingly, they have discovered that Santa Cruz steelhead exhibit markedly different behavioral patterns compared to their North American cousins – spawning many more times and living much longer.

Like most steelhead, juveniles spend an average of two years in the river before making their first out-migration to sea. Surprisingly, this is where the similarities end. Most Santa Cruz fish never stray far from the estuary and make their first run upriver after only 6 months in the salt. Many of these juvenile steelhead do not spawn during their first run, but will spawn the following year and repeat this cycle every year, spending roughly six months feeding at sea and six months fasting in the river. Thus, unlike most North American steelhead that attain large sizes by spending extended periods of time in the ocean and seldom spawn more than once, Santa Cruz steelhead instead grow to impressive dimensions by repeated spawning events. Incredibly, biologists have documented fish spawning up to seven times and reaching 11 years of age. There is some evidence that older fish stray farther from their natal river (although not necessarily for longer periods of time), and a few have even been captured as by-catch in fishing nets as far north as Mar del Plata, some 1000 miles north of Santa Cruz. Either way, the fact that only six months of feeding in the ocean is sufficient to grow such remarkable specimens is indeed a powerful testament to the incredible fertility of the surrounding marine environment.

Fish begin to run up the river in February (the end of summer), with the peak of the migration occurring in late March or early April. The average specimen weighs between 4 and 15 pounds (notwithstanding juvenile “half-pounders”), although a few 20lb behemoths do exist. Exactly how many fish return to the river in a given year, however, remains a mystery. The Santa Cruz’s opaque glacial waters preclude spawning-bed surveys, so there isn’t enough information to even make an educated guess or determine where most of the spawning occurs. Still, radio-tracking technology has enabled biologists to make another interesting discovery. Although the exact spawning areas remain unknown, spawning is believed to take place exclusively within the main river, unlike North American steelhead who generally utilize tributaries as well.

But with so many unique characteristics and an ambiguous ancestry, some may ask, “are these really steelhead?” Well, if we label any rainbow trout that exhibits anadromous behavior a steelhead, then the answer is a resounding yes. However, biologists have also shown that significant intermixing occurs between resident and anadromous populations, where resident mothers can have anadromous offspring, and vice versa. Since both populations are genetically identical, environmental factors may play a larger role in determining anadromy than in North American stocks, where resident and anadromous populations are determined by parental heritage and more clearly delineated. Therefore, the answer to the question of whether or not these fish are indeed “true steelhead” is unclear. Why two markedly different life histories are observed within the same population on the Santa Cruz is indeed a mystery, a mystery perhaps best explained by vagaries of natural adaptation. Whatever the case may be, this one of a kind fish certainly fights like a steelhead – especially the aerobatic females – and any fish that decides to turn into the powerful current can empty a reel in an instant.

Quite fittingly, this unique run of fish inhabits an equally unique river. The second largest in Argentine Patagonia (after Río Negro), the glacial-fed Santa Cruz begins high in the ice-capped Andes as the outflow of the largest exclusively Argentine lake, Lago Argentino. At over 370,600 acres in area, it ranks as South America’s third largest lake and is fed by the expansive Southern Patagonian Ice Field, the third largest freshwater reserve on the planet. From its source at the eastern end of the lake, the Santa Cruz courses 380km eastward through one of Patagonia’s most wild and remote regions before emptying into the South Atlantic near the small town of Piedra Buena. Its unforgiving and untamed glacial waters surge relentlessly through an equally unforgiving and untamed landscape where desiccated, gray brush scrub extends endlessly in all directions. Wildlife such as guanacos, foxes, rheas and even pumas are abundant, and in some sections, it’s not entirely uncommon to go days without seeing another person. Further lending to the land’s haunted quality are ancient Tehuelche arrow heads which litter the banks in many places.