It can be fairly difficult to distinguish Dolly Varden vs Arctic Char during certain seasons, so don’t feel bad if you cannot tell them apart. In fact, many fishing guides and biologists have a hard time distinguishing the two by their phenotype, or physical appearance most of the year. Both species belong to the char family and are not true trout. They are similar in that both species become brightly colored in the fall prior to spawning, especially the males. But to this, autumn is when they are easiest to tell apart.
These two separate species of char vary in physical characteristics. For example, their respective coloration and tail shape.
In some Alaskan watersheds there are even anadromous forms of dolly varden, whereas Alaskan arctic char do not go to sea.
While in freshwater, both species have similar diets. They both rely heavily on salmon for nutrition and both follow similar spawning habits. From the fly anglers perspective, we typically fly fish for dolly varden and arctic char with similar tactics!
How to tell Dolly Varden vs Arctic Char
There are three easy ways to help determine if the fish in your net is a dolly or arctic char!
The easiest place to start looking is at the fish tail. If it’s a noticeably forked tail, it’s likely an arctic char. Dollies tails’ are comparatively more squared-off.
The next feature to look at is the size, quantity, and color of spots on the fish. Fewer and larger spots (15-20 below lateral line) are typical of arctic char. Arctic char also have a creamier spot coloration.
Dollies have more spots below their lateral lines. These spots are smaller and often red in color.
Dollies and arctic charr are easier to tell apart in spawning colors. As a rule of thumb, dollies’ backs are emerald-blue, with bellies turning vibrant reds or pinks.
The spawning colors of arctic char tend to be more of a yellow-gold or orange coloration and the males’ kypes are smaller by comparison.
Dolly Varden vs Arctic Char; Life History’s
As both dolly varden and arctic char are part of the char family (like lake trout, bull trout and brook trout) they both have similar life histories. Both species spawn in the fall. Their eggs hatch in early winter, often under the ice.
From this point on, their life histories begin to differentiate, even within a species as you will learn below!
Dolly Varden Life History
Dolly Varden can have much more diversity in their life history than their cousin the arctic char. Genetically speaking, Alaska has two separate subspecies of dollies.
A “southern dolly” lives south of the Alaska Peninsula down throughout the southeast reaches of the state. This subspecies tend to be smaller in size and genetically have 82 chromosomes.
A “northern dolly” lives north of the Alaska Peninsula up through the arctic. This subspecies can grow huge! The state record Dolly Varden is 27 lbs and is from the northern species. Genetically, these fish have 78 chromosomes.
Regardless of their subspecies, dollies’ life histories become even more complex. Some Dolly Varden are anadromous, or sea-run, and some are not. Sea-run dollies spend portions of their life in the ocean and come back to freshwater to spawn. Unlike salmon, they can do this multiple times. Freshwater ‘resident’ dollies stay in their rivers and typically don’t grow as big.
Arctic Char Life History
According to the Alaska Department of Fish and Game’s genetic research, arctic char are NOT anadromous anywhere in Alaska. However, there are anadromous forms of arctic char in Kamchatka, such as the Super Kundza. In regards to Alaskan arctic char, much of their life histories remains somewhat mysterious.
Arctic char spawn in lakes, many of which are nutrient poor. This often leads to ‘dwarfed’ specimens because growth is so slow in these cold lakes. However, some lake systems are shared with salmon, this provides more nutrient opportunities and can see arctic char grow upwards of 18 lbs! Some of these fish have been recorded to live up to 20 years old, and the largest fish are suspected to be in the Bristol Bay region.
Confused yet? Well, to make distinguishing dollies from arctic char even more difficult let us quickly look at the infamous Tree River in Canada’s arctic. The Tree River produces the largest “arctic char” in the world, or so they thought. With some genetic analysis it has been determined that some of these massive fish are in fact dolly varden and even stranger, some of them are a naturally occurring hybridization of arctic charr and dolly varden.