Lake Thingvallavatn’s brown trout are pure eating machines with ravenous appetites. They are among the most beautiful, well fed, and powerful trout in the world, and the key to understanding their impressive physique and growth rate is to examine the lake’s biomass and geothermic conditions.
“On one hand, we’ve just experienced the best brown trout fishing of our lives. On the other hand, there’s this unlikely sense that we’ve only just scratched the surface, that Lake Thingvallavatn is capable of so much more.”
First, Lake Thingvallavatn’s brown trout are mainly piscivorous. There are four different subspecies of arctic char in the lake, all of which are available in massive quantities, and together with the estimated 85 million sticklebacks that flutter and swarm along the lake’s shores, the brown trout have access to abundant, high-protein food sources.
Second, there are several places in the lake where fish are able to hypereffectively digest whatever prey items they just engulfed. Following a feeding spree in open water, a trout can simply head into one of the many geothermic areas, where tributaries and hot springs converge and create optimal water temperatures. Here, a trout’s metabolism skyrockets, and fish can digest their food up to 10 times faster than the average brown, so not much time passes before fish are rested, digested, and back on the prowl. Additionally, since the process continues throughout the year, the fish exhibit unprecedented growth rates.
Some last keys to understanding why Lake Thingvallavatn’s brown trout grow so big is they can live to be up to 15 years old, and that their spawning habits are somewhat special. While brown trout elsewhere in the world spawn every year, it’s not uncommon for Thignvallavatn brown trout to get so preoccupied with feeding that they simply “forget” to spawn. In fact, it’s somewhat normal for Thingvallavatn brown trout to procreate every other year, though spawning lapses of up to three or four years aren’t unusual either. That said, the spawning runs and hiatuses are relatively short, which means spawning doesn’t exact too great a toll on the fish, and the spawning-related break from the feeding fest in the lake is short-lived.
The fishing in the lake is incredibly diverse. On calm days, for instance, you can experience some exciting sight-fishing opportunities with nymphs and dry flies. In some tributary mouths, you can fish like you’re in a river, using cross-current presentation techniques, line mends, and strike indicators. And though the wind might be howling—which it does annoyingly often in Iceland—you can blind-fish with streamers. Systematically searching the shoreline for schools of fish with small, rapidly retrieved stickleback and arctic char imitations is a rather arduous type of fishing, but it can produce some real monsters.
Access to the lake can be a little tricky because most of the shoreline is privately owned and there’s a significant lack of public roads. There is public access in the northern end by way of Thingvellir National Park, and fishing licenses for that portion can be bought via the national fishing license provider Veidikortid (www.veidikotid.is).
The lake’s best fishing is without a doubt on two beats managed by ION Fishing (www.ionfishing.is). Þorsteinsvík and Ölfusvatnsárós are the breakneck names of these two beats, and here you can experience what is probably the best brown trout fishing in the world. Because of stable water temperatures and the beat’s proximity to deep water, the fishing is superb from the April 20 season opener until the season closes on September 15. In total, four rods are available per day on a fly fishing–only, catch-and-release basis, and they are sold for 300 euros (approximately US $325) per rod.
Hoarse winds seem to be forever sweeping the barren and twisted lava landscapes of Iceland. But as we round up the fishing on the ION beats, the winds picked up immensely—the equivalent of a raging storm. For the last two days, massive, foaming waves pound the gritty lava shores and we struggle just to land a fly on the water. The fish are out there—we can see them boiling on the crashing waves—but they’re too far out.
We’re close to giving up, but as fate has it, we’re lucky enough to get one final window of opportunity. On our last day, the winds unexpectedly die down and shift direction. The small, secluded bay that we’ve been fishing at beat number one calms down to the point that we can actually cast, and a giant school of brown trout ranging from 2 to 8 kilograms is suddenly within reach. A magical hour later, we have hooked and landed more fish than we can count, and while the real monsters we’ve seen boiling in the waves earlier in the day elude us, we have caught more than a handful of fish that would make most brown trout fishermen anywhere in the world morbidly jealous.
As we pack up and leave, I’m swamped by ambiguous feelings. On one hand, we’ve just experienced the best brown trout fishing of our lives. On the other hand, there’s this unlikely sense that we’ve only just scratched the surface, that Lake Thingvallavatn is capable of so much more. One week after I return home, my gut feeling is confirmed. An Icelandic friend of mine relays a report of experiencing the ION beats at their best, on a calm and temperate evening no less. Having landed numerous 3- to 8-kilogram fish topped by three incredibly well built monster brown trout measuring 90, 95, and 101 centimeters (35 to 40 inches), he probably had the best brown trout fishing any angler can encounter.
I’m still a little shaken by my time at Lake Thingvallavatn, and as I write this, I revisit a lot of the questions that spun through my head when I boarded my plane in Reykjavik, left Iceland behind, and flew home. After fishing Iceland’s Jurassic lake, I wonder where I can go to get my next brown trout fix. But as I conclude my writings, I’m more and more certain of the answer to that question: I can go back to Thingvallavatn!
Rasmus Ovesen is a Danish freelance fly fishing journalist and photographer residing in Oslo, Norway. A fly fisherman since the age of eight, he has traveled extensively across the globe in search for trout, char, and salmon over the last 25 years