Salvelinus namaycush

Lake Trout

FWS Focus

Overview

Characteristics
Overview

Lake trout are the largest of the freshwater char. They have been reported to live up to 70 years in some Canadian lakes. They are native to northern North America, from Alaska to Nova Scotia and throughout the Great Lakes.

The Great Lakes lake trout recreational fishery is worth more than $7 billion annually and supports more than 75,000 jobs. Anglers come from all over the globe for quality fishing experiences, including angling for one of the largest apex predators in the Great Lakes - lake trout.

Scientific Name

Salvelinus namaycush
Common Name
lake trout
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Most lake trout inhabit deep lakes greater than 50 feet, but you can find them at depths well over 200 feet too! They also are found in deep freshwater rivers, which are tributaries to large lakes like the Great Lakes. 

River or Stream
River or Stream
Lake
River or Stream
Lake
River or Stream
Lake
Characteristic category

Behavior

Characteristics
Behavior

Lake trout feed on a variety of organisms from plankton to small invertebrate animals to ?sh. Young lake trout generally eat plankton, insects and small invertebrates, while adults prefer to eat fish. Some lake trout populations feed on plankton throughout their lives and attain smaller sizes than their piscivorous (fish-eating) counterparts. Most lake trout, however, are top predators, feeding on fish in the Great Lakes. As a top predator, they are very important to maintaining a healthy balance in the food web of the lake.

Characteristic category

Physical Characteristics

Characteristics
Color & Pattern

There are several variations of Lake Trout that are found in North American lakes.  In general though Lake Trout are have spots covering their body that can range in color from white to yellow tint. Nearly all Lake Trout have a darker color on their top half. Often a dark green, brown or greyish color.  They have a much lighter colored belly.  This offers the Lake Trout excellent camouflage in their environment.  The darker color when seen from above makes the trout blend in with the dark depths of the lake while the lighter belly allows the trout to blend in with the sun and lighter color of the water above them. This adaptation allows the Lake Trout to stay hidden from all directions as it hunts for smaller fish and avoids larger ones.  Depending on where the Lake Trout is from you may see some of the color variations such as a more yellow looking fish or one with a red hue in their fins.   

Size & Shape

Lake trout often reach 3 feet in length with the longest lake trout on record at 50 inches.

Weight

Lake trout often weigh up to 40 pounds. The maximum weight ever recorded is 102 pounds from the state of Alaska.  

Physical Characteristics

Lake Trout are a non schooling fish that spend the majority of their time in the deeper waters of the lakes where they search for food.  Lake Trout have been found living quite comfortably at depths of several hundred meters.   

Characteristic category

Life Cycle

Characteristics
Reproduction

Lake trout normally spawn during the fall months, from October through November. They spawn over boulder beds where water currents keep the rocks clear of silt. Lake trout do not dig nests, but the early arriving males clear away algae and other debris by fanning the rocks with their fins and scraping them with their bodies. Spawning takes place over the rocks. Several males and females may form a spawning group, and spawn many times over several days or weeks. The fertilized eggs sink to the bottom into the protective crevices of the rocks where water currents keep the eggs oxygenated and silt free.

A single female may lay 2,000 to 20,000 eggs depending on her size. The fertilized eggs develop and hatch into free swimming alevins in February and March. The alevins live in the rock crevices for another few weeks while they complete fin development. The young lake trout then disperse across a variety of lake habitats, where they search for zooplankton and try to avoid predation by other fish species.

Lifecycle

In the fall Lake Trout gather on rocky reefs where they were born to spawn.  These fish do not build a nest for their eggs, instead Lake Trout are broadcast spawners.  This means that the eggs are released and fertilized externally and then left to fend for themselves.  On these reefs the eggs fall into the cracks in-between the rocks where they will hopefully be protected from predators and the currents of the lake.  Over the course of the winter the eggs incubate and develop. The rate at which the young fish grow is very dependent on the water temperature. The difference between a few degrees can speed up or slow down the development by several weeks!  When they first hatch the fry aren't fully developed.  Their mouths are still attached to the yolk sac from the egg.  For several weeks they absorb this yolk sac for nutrients while they finish developing. At this stage they are known as sac fry.  Once the yolk sac has been absorbed the small fry will begin to search for food.  It has been observed that the small fry will make a nightly migration from the depths of the lake to the surface waters where it will hunt for phytoplankton, small invertebrates and small fish under the moonlight. The Lake Trout will continue to grow throughout its life and will reach sexual maturity at around 7 years of age where it then can repeat this cycle.

Lifespan

Lake Trout often live well into their 20s.  With some of the oldest Lake Trout living beyond their 60s

Characteristic category

Food

Characteristics
Food

Lake trout feed on a variety of organisms from plankton and small invertebrate animals, to ?sh. Young lake trout generally eat plankton, insects and small invertebrates, while adults prefer to eat fish. Some lake trout populations feed on plankton throughout their lives and attain smaller sizes than their piscivorous, or fish-eating, counterparts. Most lake trout, however, are top predators, feeding on fish in the Great Lakes. As a top predator, they are very important to maintaining a healthy balance in the food web of the lake.

Geography

Characteristics
Range

Lake trout are native to northern North America, from Alaska to Nova Scotia and throughout the Great Lakes. They were introduced in some states west of the Rocky Mountains, where they are not native. 

Import/Export

Lake Trout harvesting used to be almost completely unregulated until the second half of the 20th century. During this period their population was decimated in the Great Lakes. After years of regulation and restoration programs organized by the American, Canadian, state and provincial governments the Lake Trout numbers have been increasing. Each state and province has its own regulations for how many Lake Trout can be taken from its lakes. 

 

 

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