Lake whitefish

What it is

This fish belongs to the salmon family and shares traits like an adipose fin with its relatives. It has a small head relative to its body length, earning it the nickname humpback. The snout overhangs the lower jaw, allowing it to feed near the bottom. Its scales range from silver to white, with olive or brown tones on the back. Ventral fins are white, and the tail features a dark rear edge. Two small flaps sit inside each nostril. Adults typically weigh around four pounds, though some reach five pounds or more.

Where it lives

Its distribution covers Alaska and western Canada east to the Atlantic drainage of Maine and New Brunswick. Populations extend north to Labrador. The species inhabits numerous inland lakes and occasionally enters brackish environments. It thrives in cool waters across this broad northern range. The Great Lakes hold significant populations, particularly in the upper lakes. This wide geographic spread allows it to occupy diverse aquatic habitats within North America.

How it lives

Larvae feed on plankton until they reach three to four inches in length. Adults then switch to bottom-dwelling prey such as snails, insect larvae, and clams. In late summer, some groups rise to feast on emerging mayflies and midges. Natural enemies include burbot, lake trout, and northern pike. Young fish are indistinguishable from cisco by appearance alone, requiring genetic tests for identification. Predators hunt them in both deep and shallow zones depending on the season.

Breeding and life cycle

Spawning occurs between September and January during nighttime hours. Mature fish move into shallow areas to lay eggs on rubble and gravel shoals. Water depth at these sites ranges from two to four metres. No parental care follows egg deposition. The young hatch the following spring. In northwestern regions, large migrations enter deltas like the Athabasca in late summer. Tagged individuals have recorded movements of over 200 miles upstream.

Fish and people

It is a prime commercial species in the Great Lakes, prized for its delicate flavour. Annual harvests once averaged eleven million pounds, though recent figures have declined. Fillets are sold smoked, refrigerated, or vacuum-packed in grocery stores. Sport anglers target them in summer using jigs for surface-feeding fish. Winter ice fishing is popular in places like northern Wisconsin. Guides often use jigging spoons tipped with wax worms for successful catches.

Status and threats

Invasive sea lampreys have threatened populations since the 1930s, particularly in Lake Michigan. These parasites likely entered through canal systems like the Erie and Welland Canals. Quagga mussels also pose a risk by filtering out zooplankton, which juvenile fish need for food. Despite these pressures, the species remains a staple of inland fisheries. Conservation efforts focus on managing these invasive threats to maintain healthy stock levels.

Relatives and look-alikes

It closely resembles the northern cisco, another member of the whitefish subfamily. Both share similar early life stages and physical traits like the adipose fin. However, the cisco has a lower jaw that extends beyond its snout. Genetic analysis is often required to distinguish young individuals of these two species. Dwarf and normal ecotypes exist within lake whitefish populations, adapted to different lake zones.

Questions people ask about Lake whitefish

Good reading and sources

• Lake whitefish on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data