Animal Diversity Web

Ge­o­graphic Range

Acipenser ful­vescens oc­curs in the fresh­wa­ters of North Amer­ica from the Hud­son Bay through the Mis­sis­sippi River drainages to Al­abama. It is found along the Great Lakes - St. Lawrence River drainage and in large lakes in New York and Ver­mont, in­clud­ing Cayuga Lake and Lake Cham­plain.

• Biogeographic Regions
• nearctic
  • native

Habi­tat

The lake stur­geon is a fish of tem­per­ate wa­ters and is found only in the North­ern Hemi­sphere in North Amer­ica. Their habi­tat is usu­ally on the bot­tom of a riverbed or lake. Acipenser ful­vescens pre­fer a river or lake bot­tom that has clear sand or gravel. (Her­ald 1971)

• Aquatic Biomes
• lakes and ponds
• rivers and streams

Phys­i­cal De­scrip­tion

This fish has a skele­ton partly of bone and partly of car­ti­lage. Their slen­der bod­ies are cov­ered with rows of bony plates. Be­neath the pro­ject­ing snout there is a small, tooth­less mouth with thick, suck­ing lips. There are four bar­bels (whiskers) in front of the mouth that are used to di­rect food to­wards the mouth. Like the body, the head is well pro­tected with plates. A sin­gle dor­sal fin rises from the back, and the body ex­tends into the long upper part of the tail fin. (World Book En­cy­clo­pe­dia 1998)

The phys­i­cal char­ac­ter­is­tics of Acipenser ful­vescens vary greatly with age and size. In the young, the body shields are rough and or­na­mented with hooked spines. As they be­come adults, the shields grow smoother. Many of them even­tu­ally dis­ap­pear with age. The snout also grows less pointed with age, and the spots of the younger fishes' color pat­tern dis­ap­pear. It is com­mon for the lake stur­geon to reach a length of about 1.8 me­ters and have a mass, on av­er­age, of 90 kilo­grams. (En­cy­clo­pe­dia Amer­i­cana 1996)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Average mass

  90 kg

  198.24 lb

• Average mass

  70000 g

  2466.96 oz

  AnAge

Re­pro­duc­tion

In early sum­mer, lake stur­geons mi­grate to­ward the shores of fresh­wa­ter lakes for spawn­ing pur­poses. They seek out peb­bly habi­tats with no mud to breed. (Evans 1994) Spawn­ing usu­ally takes place at a depth of 5.4 to 6.0 me­ters. The fe­males lay a vast num­ber of eggs, any­where from 2 to 3 mil­lion in one sea­son, de­pend­ing on their size and age. After spawn­ing, the eggs are left to de­velop on their own. The par­ents will then re­turn to the lake or river where they spend most of their time. (Rodgers 1990)

The eggs, or roe, are small and sticky. They are en­cased in a jelly-like sub­stance and use the stick­i­ness to ad­here to water plants and stones, or clump to­gether in masses. This al­lows them to re­main sta­tion­ary and stay in one lo­ca­tion de­spite the cur­rent. The eggs are one-fourth of a cen­time­ter in di­am­e­ter and black­ish in color. They will nor­mally hatch in three to seven days. The lar­vae are 1.25 cen­time­ters long and by the first sum­mer may grow to a length of 20 cen­time­ters. The young grow rapidly until ma­tu­rity, after which growth con­tin­ues slowly for sev­eral years. (Rodgers 1990)

Al­though the Russ­ian stur­geon (Acipenser huso) may reach a length of 30 cen­time­ters in one year, the lake stur­geon re­quires twenty years to at­tain a length of a lit­tle over a meter. Acipenser ful­vescens be­come sex­u­ally ma­ture when they are around the age of twenty and at a length of a lit­tle over a meter. (Her­ald 1971)

• Average number of offspring

  350000

  AnAge

• Average time to hatching

  6 days

  AnAge

• Average age at sexual or reproductive maturity (female)
  Sex: female

  9490 days

  AnAge

• Average age at sexual or reproductive maturity (male)
  Sex: male

  2920 days

  AnAge

Lifes­pan/Longevity

• Average lifespan
  Status: wild

  82.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: wild

  152.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Lake stur­geon are slow mov­ing fish, spend­ing most of their time grub­bing on the bot­tom for food. They mi­grate up rivers dur­ing spawn­ing sea­son. (Rodgers 1990)

• Key Behaviors
• natatorial
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• tactile
• chemical

Food Habits

The name stur­geon in sev­eral Eu­ro­pean lan­guages means "the stir­rer", from the way the fish rum­mages among the mud for food. It finds its food largely by touch, using its sen­si­tive bar­bels. As the lake stur­geon cruises over the bot­tom, the sen­si­tiv­ity of the fleshy whiskers trail­ing in the sand makes up, to some ex­tent, for the fish's poor eye sight. As soon as the whiskers pass over food, the pro­trusi­ble mouth drops down with an el­e­va­tor-like mo­tion and rapidly sucks in its meal. (Her­ald 1971) Acipenser ful­vescens are one of the few fishes to have taste buds on the out­side of their mouth. In other fish, they are nor­mally found on the tongue or in­side the mouth. The taste buds of the lake stur­geon pro­trude from the tooth­less mouth and are used to help in the se­lec­tion of food.

These fish are slow feed­ers and can sur­vive sev­eral weeks with­out eat­ing. More­over, the food it eats is small com­pared to its own size. The lake stur­geon, in its nor­mal habi­tat, must de­vote a great deal of time to feed­ing. Acipenser ful­vescens eat in­sect lar­vae, worms, cray­fish, snails, and other small fishes. (Rodgers 1990)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The lake stur­geon is best known as a food fish. Their un­fer­til­ized eggs, car­ried in­side the fe­male, are con­sid­ered a del­i­cacy. These eggs are the lux­ury food known as caviar. The meat of this fish is also eaten. Lake stur­geon have been fished for their flesh and their oil as well as for their caviar. Steam­boats in North Amer­ica once used their oil as fuel. They have also sup­plied isin­glass. Isin­glass is a form of gelatin and is ob­tained from the stur­geon's swim­blad­der and ver­te­brae. It was tra­di­tion­ally used to clar­ify wines and as a gelling agent in jams and jel­lies. Today, it is used for spe­cial ce­ments and wa­ter-proof­ing ma­te­ri­als, but its main use is in clean­ing white wines. (Evans 1994)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

The lake stur­geon does not ap­pear to pre­sent any neg­a­tive at­trib­utes con­cern­ing the en­vi­ron­ment or hu­mans.

Con­ser­va­tion Sta­tus

Lake stur­geon pop­u­la­tions have de­clined in the last cen­tury. This is due partly to over­fish­ing, pol­lu­tion of rivers, and to some ex­tent be­cause river damming has de­stroyed spawn­ing runs. (Rodgers 1990)

Lake stur­geon used to be one of the most im­por­tant fish in the Great Lakes. Heavy fish­ing and pol­lu­tion from newly de­vel­oped land around the lakes has caused it to be­come very rare. (Evans 1994) Lake stur­geons are listed as threat­ened by the state of Michi­gan.

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  Appendix II

• State of Michigan List

  Threatened

Other Com­ments

Some species of stur­geon are the largest and most long-lived fresh­wa­ter fishes. In 1953, a lake stur­geon was caught that was es­ti­mated to be 154 years old. The largest is the Russ­ian stur­geon (Huso huso), or bel­uga. It can reach a length of 8.5 me­ters and has been known to weigh over 1500 kilo­grams. ()

To view video of lake stur­geons, visit this site: http://​www.​greatlakesfishes.​com/​. (Ravenswood Media, Inc., 2005)

Con­trib­u­tors

Tanya Dewey (au­thor), An­i­mal Di­ver­sity Web.

Di­anna Stur­geon (au­thor), Mil­ford High School, George Camp­bell (ed­i­tor), Mil­ford High School.

Ref­er­ences

Her­ald, Earl S., 1971. Liv­ing Fishes of the World. Gar­den City: Dou­ble­day and Com­pany Inc..

Ravenswood Media, Inc., 2005. "Great Lakes Fishes" (On-line). Ac­cessed July 05, 2005 at http://​www.​greatlakesfishes.​com/​.