During the back half of our season at Alaska West, we’re lucky to witness a pretty amazing run of dolly varden, a species of char native to Western Alaska. Arguably one of the prettiest fish in our river, they’re also available in laugh-inducing numbers, making them an awesome fish to target on a fly rod.
Because of that, we get a lot of requests for more posts on our beloved dollies. So, we reached out to Jordan Sly, our operations manager here at Alaska West, for all the details on the life history of dolly varden. Aside from spending a lot of time on the Kanektok, he also has a Master’s degree in fisheries ecology, so if you want to know more about dolly varden, you’re going to want to keep reading.
All About Dolly Varden
It’s late July, and that means Dolly Varden Salvelinus malma are starting to stack up on what we like to call “Dolly Flats.” Dolly Varden are a species of salmonid native on the west coast of the United States and Canada, as well as in parts of Asia and Russia. They are a true char, and are closely related to Bull, Brook, and Lake Trout, in addtion to Artic Char. The easiest way to tell a true char from a true salmon or trout is that a char will have lighter spots on a darker body.
Dolly Varden are super aggressive to take almost anything put in front of them, but they love flesh flies and beads above all else. One really fun way to fish for them is what we like to call “wake and eggs,” it is not the most productive method of fishing for them, you will not see the huge numbers you can get with a flesh fly or a bead, but it is visual, on top-water, and very exciting to do. The preferred method is done with a small switch or spey rod, floating lines, and a small skater/egg pattern. Dolly Varden will follow the skating fly, and often grab the egg mid swing, creating a really fun fishing experience. We will go more in depth into the fishing side of things in the coming weeks, but let us first talk about our beautiful Dolly Varden we have here on the Kanektok River.
Dolly Varden can have a very complex and interesting life-cycle, they can be anadromous (sea-run), adfluvial (lake-run), fluvial (migration within a river system), or lacustrine (lake only). The majority of our Dolly Varden here on the Kanektok River are partically anadromous, meaning they will go out to sea for a couple months and return a little bigger and very silver in color. As they hold in the river system they will start to put their “makeup” on and they will soon “clown up.” Meaning they are in their spawning colors, which is very colorful and amazing to look at. Dolly Varden are iteroparous spawners, meaning they will spawn multiple times, so after the process is done they will slowly migrate back down stream to repeat the cycle again. Dolly Varden are considered partically anadromous because they never spend much time in the salt like true salmon do, they will go off shore, but never very far, and pop in and out of different river systems along the coast, mainly staying in estuaries.
When smaller, Dolly Varden are known as a opportunistic feeder, meaning they will eat whatever they can whenever they can, but when they get larger in size they become dominatly piscivorous, meaning they eat mainly fish and fish parts. A lot of the reasons for this change in diet have to do with the increased nutritional intake a fish receives when digesting other fish relative to insects.
Spent energy of a salmonid can be simplified into three catagories. The first one is energy burned to find resources and evade predators, second is actual growth, and the last is the growth of reproduction organs. So basically salmonids will burn the first calories to find food, and not get eaten. Once they have accomplished this the next calories burned will go into growing bigger, after this reproduction organs will grow. So the less energy spent looking for food, the larger a fish can grow and the more eggs/sperm it can produce for future generations. This is important to understand when considering Dolly Varden feeding habits.
Every organism, not just salmonids, need nutrient intake to thrive. The ratio of the different nutrients (Carbon to Nitrogen mainly) will determine how much a organism can absorb, and how much will be dispelled as waste. Salmonids are no different, and the best source of nutrients for one is another salmonid because everything is already the same ratio.
Another large factor that influences Dolly Varden feeding habits is the growth period here on the Kanektok River. The Kanektok River is a cold place during the late fall, winter and early spring, not much is happening in regards to new life other than little fish hatching out of the gravel. The food source in the river goes down drastically when compared to the summer months that are packed full of flesh from spawned out salmon and the millions of eggs being dropped all over the river system. Dolly Varden have only a couple months in the summer to eat a large quantity of food, that will help sustain them until next year, and allow them to migrate out to the estuary again.
By combining these factors, one can understand why Dolly Varden eat the way they do. They are known to be extreamly aggressive, and will devour almost anything put in front of them, especially if it is a piece of flesh or an egg imitation. Dolly Varden do this because they want to use as little energy as possible to get the most nutrients they can, in a small amount of time. Being dominantly piscivorous, Dolly Varden are getting the most nutrients they can for each piece of food they eat, and they are not using much energy to do it because they do not have to chase it down.