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Dolly Varden (Salvelinus malma)

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Species overview

Physical description

Illustration of a brown Dolly Varden with orange and red spots. Refer to physical description.
Dolly Varden (Salvelinus malma)

Dolly Varden is a species of char with a slightly rounded body, and large head and eyes. It has well-developed teeth on both jaws. Breeding males of some anadromous populations have a well-developed kype, or hook-like structure, on the bottom jaw.

Dolly Varden’s colouration varies with habitat, size, and region. Anadromous adults are typically dark blue on the back and head with silver sides. Non-anadromous adults have an olive-green to brown back with light-coloured sides, except when breeding, when their sides turn red. In some areas, they are always red. The back and sides are spotted with yellow, orange, or red. Breeding males become more dramatically coloured, while females remain mostly the same.

Dolly Varden’s length depends on the latitude and life history of the population. Northern populations grow slower and stay smaller than southern populations. Anadromous populations are usually larger and grow faster than non-anadromous populations.

Distribution

Dolly Varden is found in both freshwater and saltwater in western North America and eastern Asia. In Canada, it occurs in:

There are 2 forms, or subspecies, of Dolly Varden:

  1. northern (Salvelinus malma malma)
  2. southern (Salvelinus malma lordi)

Each form has anadromous and non-anadromous populations. There are 6 known stocks in Canada of the northern form Dolly Varden.

Adult Dolly Varden are found in cold lakes, rivers, and the sea. Anadromous adults at sea are usually near shore around the mouths of rivers or in tidal waters. Anadromous adults spend roughly 60 to 160 days at sea.

Life cycle

Dolly Varden spawns in the fall between September and early November. Anadromous fish migrate from the sea to rivers in summer and fall. Non-anadromous fish make a similar migration from lakes to rivers. Spawning usually occurs when water temperature is around 8°C and in waters with some current.

A nest, called a redd, is dug by female Dolly Varden to lay eggs. After eggs are laid, females cover the nest and adults move downstream to recuperate. Eggs hatch in the spring about 4.5 months after they were laid. Newly hatched Dolly Varden are called alevins. They remain on the bottom around the nest until their energy reserves are used up and they require food. Young Dolly Varden spend 3 to 4 years in streams before migrating to either the sea or to lakes.

Dolly Varden reach maturity at 2 to 6 years old. Males often mature earlier than females. Non-anadromous populations mature younger than anadromous populations. On average, Dolly Varden lives to 10 to 12 years, but some individuals have lived to 20 years old.

Fishery history

Dolly Varden is an important species for recreational, commercial, and particularly subsistence fisheries. It is most commonly caught in gillnets or seines for subsistence purposes.

Dolly Varden was caught commercially for a short time in the 1960s, but this was stopped due to over-fishing and conservation concerns. The recreational fishery for Dolly Varden increased after 1950. There is currently a limited recreational fishery within Ivvavik National Park and Herschel Island Qikiqtaruk Territorial Park.

There is a subsistence fishery for anadromous Rat River Dolly Varden that occurs for about 40 days per year. Population abundance declined from 2000 to 2002 and harvest restrictions were put in place in 2006 by the communities of Aklavik and Fort McPherson. Other subsistence fisheries still exist today in the Inuvialuit Settlement Region and Gwich’in Settlement Area.

Ecosystem context

Dolly Varden has a diverse diet including:

Dolly Varden was once viewed as a large threat to salmon because they predate on young and eggs. Adult Dolly Varden compete with salmon for food and spawning grounds where they cohabit. In Alaska, fishers were paid in the 1930s to catch and destroy Dolly Varden by the thousands.

Dolly Varden is threatened by:

Northern form Dolly Varden depends on areas with discharging groundwater springs for:

This makes it susceptible to habitat fragmentation and disruption. Northern form Dolly Varden was listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as a Species of Special Concern in 2010. Additionally, it was listed under the Species at Risk Act (SARA) in 2017.

The predictability of the Dolly Varden life cycle (i.e., migration times and locations) increases its susceptibility to over-harvesting. Changes in environmental factors, like decreased temperature, can cause early spawning, which reduces feeding time and fishing impacts and exposes eggs to unknown water level fluctuations.

Anadromous Rat River Dolly Varden have seen an increase in growth rate recently due to the early break up of sea ice. This may allow for an earlier bloom of zooplankton, giving the fish early access to abundant, high-quality food.

Science advice and research

Science advice and research for Dolly Varden

Integrated Fisheries Management Plan

Integrated Fisheries Management Plan for Dolly Varden

Sources

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