Geographic Range
Lake whitefish are found throughout northern North America. They are found in cold
waters from the Great Lakes north through almost all of Canada and into Alaska.
Habitat
Lake whitefish are found mainly in large, cold, freshwater lakes and their drainage
basins. They may occasionally enter brackish water. They make small, seasonal migrations
between different water depths. They are found in deeper water in summer and winter,
returning to shallower water in spring and then again in fall or early winter to spawn
over rocky shoals and reefs along lakeshores. They can be found at water depths from
5 to 128 meters or deeper, although ranges of 15 to 37 meters are more typical.
- Habitat Regions
- temperate
- freshwater
- Aquatic Biomes
- lakes and ponds
- rivers and streams
Physical Description
Lake whitefish average 457 mm in length, although there is large variation in size
in local populations. They are covered in scales that range from pea green or almost
brown dorsally to silvery white ventrally. The sides have a bluish hue and the fins
are nearly transparent. There are two dorsal fins, including an adipose fin which
is sometimes larger in males. Dorsal and anal fin rays are usually 11 (range 10-12),
pectoral fin rays are from 14 to 17. The nose is blunt, with a small, subterminal
mouth. Lake whitefish are long and laterally compressed, as are most
salmonids
. Males and females have breeding tubercles on the head and body. The maximum recorded
weight was 19 kg (Lake Superior, 1918), although lake whitefish are considered very
large at 9 kg. Average weight is more like 1.8 kg. The maximum recorded length was
100 cm, all individuals longer than 467 mm are considered mature adults.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- sexes shaped differently
Development
Lake whitefish spawn over shallow water shoals. Spawning occurs in fall and early
winter and the eggs are broadcast over the shoals, where they settle to the bottom.
Eggs hatch in March or early April, taking about 133 days to hatch in waters averaging
1.7 degrees Celsius. Time to hatching increases with decreasing water temperature.
In laboratory settings, optimum water temperature for incubation is 3.2 to 8.1 degrees
Celsius. Hatching took only 41.7 days in water at 10 degrees Celsius, and 182 days
at 0.5 degrees Celsius. Larvae average 13.25 mm in length at hatching and grow about
25 mm per month in their first season. There is little known about lake whitefish
development between the larval and adult stages.
Reproduction
Lake whitefish spawn in large groups over shallow water shoals in fall and early winter.
Spawning occurs at night. Females repeatedly rise to the water's surface while releasing
eggs. They are accompanied by either one or two males who simultaneously release their
milt onto the eggs. Spawning is accompanied by a lot of jumping and surface activity.
- Mating System
- polygynandrous (promiscuous)
Lake whitefish spawn in the fall or early winter and eggs hatch in the early spring.
Females release thousands of eggs when they spawn, the number of eggs depends on body
size. One female that weighed 907 g had 25,000 eggs and another female that weighed
5.9 kg had 130,000 eggs. Males mature at a minimum length of 368 mm, females at 419
mm.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
Lake whitefish males and females do not care for their young after the eggs have been fertilized.
- Parental Investment
- no parental involvement
-
pre-fertilization
- provisioning
-
protecting
- female
Lifespan/Longevity
Most mortality of lake whitefish occurs at the egg and larval stages. Only about 13%
of eggs survive to become larvae and larvae are heavily preyed on by larger fish.
The maximum recorded age of a lake whitefish was 50 years old, although maximum ages
of 25 years are more typical.
Behavior
Lake whitefish are fairly sedentary in the Great Lakes, although they make seasonal
movements between deep and shallow water. They typically make 4 short, seasonal migrations:
from deep to shallow water in the spring, back to deep water in summer as water temperatures
rise, to spawning areas in shallow water in the fall and early winter, and back to
deep water in the winter. Lake whitefish are social and are always found in schools.
Home Range
Total distances traveled during migrations have been recorded at 8 to 242 km, but
the vast majority of fish do not travel more than 40 km. Schools of lake whitefish
seem to remain fairly local in their movements.
Communication and Perception
Like most fish, lake whitefish have a lateral line system that allows them to detect water movement. They also have good vision and sense of smell. In mating, tactile cues may be important as males and females coordinate to release eggs and sperm.
- Communication Channels
- tactile
- Perception Channels
- visual
- tactile
- vibrations
- chemical
Food Habits
Lake whitefish have small mouths and eat mainly small prey, including aquatic insects
(
Diptera
larvae,
Trichoptera
larvae,
Chironomidae
larvae,
Hexagenia
nymphs,
Corixidae
), amphipods (mainly
Pontoporeia
and
Mysis
), mollusks (
Sphaerium
and
Amnicola
especially), and fish eggs and fry. They have been recorded eating small
alewives
and
sculpin
. They forage mainly on or near the lake bottom.
- Primary Diet
-
carnivore
- insectivore
- eats non-insect arthropods
- molluscivore
- Animal Foods
- fish
- eggs
- insects
- mollusks
- aquatic crustaceans
Predation
Lake whitefish eggs are eaten by a host of other fish, including
yellow perch
,
ciscoes
, and other whitefish. Juvenile lake whitefish are also eaten by a host of larger,
predatory fish, including
lake trout
,
northern pike
,
burbot
, and
walleye
. Adult lake whitefish are largely preyed on by humans.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
Lake whitefish are both important prey, as eggs and young, for many other fish species,
and important predators of aquatic insects, mollusks, and crustaceans. Lake whitefish
are parasitized by introduced
sea lampreys
.
Economic Importance for Humans: Positive
Lake whitefish have long formed the basis for important subsistence and commercial
fisheries. They are not commonly sought as gamefish, although more anglers are beginning
to seek them out. They are difficult to catch with hooks because of the deep water
they sometimes inhabit and small mouths. Lake whitefish flesh is considered delicate
and delicious and the roe is valued for caviar.
- Positive Impacts
- food
Economic Importance for Humans: Negative
There are no adverse effects of lake whitefish on humans.
Conservation Status
Overfishing and environmental degradation caused a near collapse of lake whitefish
fisheries in the Great Lakes during the early part of the 20th century. Water quality
improvement and fishery management has improved populations since then, although local
populations remain threatened and the health of lake whitefish stocks has not fully
recovered under continuing commercial fishing pressure.
Other Comments
Some researchers consider lake whitefish conspecific with Baltic whitefish (
Coregonus lavaretus
).
Additional Links
Contributors
Tanya Dewey (author), Animal Diversity Web.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- freshwater
-
mainly lives in water that is not salty.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- external fertilization
-
fertilization takes place outside the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- natatorial
-
specialized for swimming
- diurnal
-
- active during the day, 2. lasting for one day.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- social
-
associates with others of its species; forms social groups.
- tactile
-
uses touch to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- chemical
-
uses smells or other chemicals to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- food
-
A substance that provides both nutrients and energy to a living thing.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- molluscivore
-
eats mollusks, members of Phylum Mollusca
References
Becker, G. 1983. Fishes of Wisconsin . Madison, Wisconsin: The University of Wisconsin Press.
Luna, S. 2008. "Coregonus clupeaformis" (On-line). fishbase.org. Accessed December 11, 2008 at http://www.fishbase.org/Summary/SpeciesSummary.php?id=234 .
Michigan Department of Natural Resources, 2008. "Lake Whitefish, Coregonus clupeaformis" (On-line). Michigan Department of Natural Resources, Fish Identification. Accessed December 11, 2008 at ttp://www.michigan.gov/dnr/0,1607,7-153-10364_18958-45680--,00.html .