ECOS Guide to the Ecology of the Northern Rockies

Name: Thymallus arcticus - Arctic Grayling

Family: Salmonidae (Trout and Salmon)

Order: Salmoniformes (Salmon/Trout/Pike)

Class: Osteichthyes (Bony Fishes)

Abundance: Uncommon

Origin: Native

Active Season: Year Round

Size:

average: 10in
largest: 20in

Colors: White-gray, pink (dorsal fin), red-orange (dorsal fin), blue-purple (dorsal fin), black (spots on front of body)

General Description: Like all members of the trout family, arctic grayling have an adipose fin and a pelvic axillary process. The young have dark vertical markings along their bodies called parr marks. Arctic grayling in particular have a large mouth and large scales. They have a large, colorful dorsal fin that looks like a sail and dark spots on the front part of their body.

Similar Species: Arctic grayling are similar to species of trout, salmon, and whitefish in body shape, however the arctic grayling is the only fish species to have a large sail-like dorsal fin.

Life History: In Montana, there are genetically different lake and stream populations of arctic grayling. Both types of graylings become sexually mature at about three years of age, and move up tributary streams in the spring to spawn over gravel beds. In Montana, arctic grayling typically only live 5 years.

Distribution: Arctic grayling are currently found throughout the arctic region from eastern Russia to the western shore of Hudson Bay. They once were found as far south as Michigan, Wyoming, and Montana, although today, the only population of native arctic grayling in the lower 48 states is found in Montana. In 1805, Lewis and Clark reported that arctic grayling were common throughout the upper Missouri drainage in Montana. Today, the native fluvial arctic grayling is restricted to a few small areas of the Big Hole River in Montana. Arctic grayling have been introduced to many mountain lakes for the purposes of sport fishing.

Habitat Description: Arctic grayling are found primarily in clear, cold lakes connected to streams for spawning. As well, a few populations live completely in streams.

Feeding Habits: Arctic grayling forage primarily on aquatic invertebrates such as mayflies, caddisflies, and stoneflies.

Enemies & Diseases: Young arctic grayling are heavily preyed on by introduced trout species such as rainbow trout and brown trout. Adults are eaten by animals that commonly prey on fish, such as ospreys, otters, minks, and herons.

Did You Know: The range of the arctic grayling in the lower 48 states has been severely reduced. It was once found in Michigan, Wyoming, and Montana, but the populations in Michigan and Wyoming have gone extinct. In Montana, the arctic grayling is currenly found in 4% of it’s former range, and most native populations exist in a small area of the Big Hole River near Wisdom, Montana. The severe declines in the lower 48 states are likely caused by a number of factors. First, the arctic grayling is very easy to catch, and populations have likely been overfished by anglers. Secondly, many habitats have been either dammed or diverted. These changes have caused increased silt deposits in lakes, or acted as barriers to moving grayling. Lastly, arctic grayling are easily outcompeted by introduced rainbow and brown trout, which eat young grayling.

The arctic grayling is now considered a species of special concern in the state, and populations are closely monitored. Several arctic grayling populations have been introduced in mountain lakes for purposes of sportfishing.

Glossary:

Adipose fin: a small fleshy fin along the midline of the back behind the dorsal fin.
Axillary process: the very small fin attatched to the pelvic fin.
Dorsal fin: a fin along the midline of the back, usually midway between the head and tail fin.
Pelvic fin: the fin on the underside of the fish nearest the head.
Spawn: the act of mating between two fish with the purpose of producing offspring.

Keywords: whitefish, salmonid, Prosopium, williamsoni

References:

Alaska Department of Fish and Game. Wildlife Notebook. Arctic Grayling. http://www.adfg.state.ak.us/pubs/notebook/fish/grayling.php

Holton, G. D. and H. E. Johnson. 2003. A Field Guide to Montana Fishes, Third Edition. Montana Fish, Wildlife & Parks, Helena, MT.

Montana Fish, Wildlife, and Parks Animal Field Guide. Arctic Grayling. http://fwp.mt.gov/fieldguide/detail_AFCHA07011.aspx

Contributor:

Allison Greene


Home Plant Guide Insect Guide Bird Guide Mammal Guide Geology Guide Fish Guide Fish by Name Fish by Family Fish by Order Glossary of Fish Terms Amphibian Guide Reptile Guide Habitats Descriptions Maps Contributors ECOS Home		Physical Characteristics - General Description - Similar Species - Life History - Distribution - Habitat - Feeding Habits - Did You Know - Glossary - References Name: Thymallus arcticus - Arctic Grayling Family: Salmonidae (Trout and Salmon) Order: Salmoniformes (Salmon/Trout/Pike) Class: Osteichthyes (Bony Fishes) Abundance: Uncommon Origin: Native Active Season: Year Round Size: average: 10in largest: 20in Colors: White-gray, pink (dorsal fin), red-orange (dorsal fin), blue-purple (dorsal fin), black (spots on front of body) General Description: Like all members of the trout family, arctic grayling have an adipose fin and a pelvic axillary process. The young have dark vertical markings along their bodies called parr marks. Arctic grayling in particular have a large mouth and large scales. They have a large, colorful dorsal fin that looks like a sail and dark spots on the front part of their body. Similar Species: Arctic grayling are similar to species of trout, salmon, and whitefish in body shape, however the arctic grayling is the only fish species to have a large sail-like dorsal fin. Life History: In Montana, there are genetically different lake and stream populations of arctic grayling. Both types of graylings become sexually mature at about three years of age, and move up tributary streams in the spring to spawn over gravel beds. In Montana, arctic grayling typically only live 5 years. Distribution: Arctic grayling are currently found throughout the arctic region from eastern Russia to the western shore of Hudson Bay. They once were found as far south as Michigan, Wyoming, and Montana, although today, the only population of native arctic grayling in the lower 48 states is found in Montana. In 1805, Lewis and Clark reported that arctic grayling were common throughout the upper Missouri drainage in Montana. Today, the native fluvial arctic grayling is restricted to a few small areas of the Big Hole River in Montana. Arctic grayling have been introduced to many mountain lakes for the purposes of sport fishing. Habitat Description: Arctic grayling are found primarily in clear, cold lakes connected to streams for spawning. As well, a few populations live completely in streams. Feeding Habits: Arctic grayling forage primarily on aquatic invertebrates such as mayflies, caddisflies, and stoneflies. Enemies & Diseases: Young arctic grayling are heavily preyed on by introduced trout species such as rainbow trout and brown trout. Adults are eaten by animals that commonly prey on fish, such as ospreys, otters, minks, and herons. Did You Know: The range of the arctic grayling in the lower 48 states has been severely reduced. It was once found in Michigan, Wyoming, and Montana, but the populations in Michigan and Wyoming have gone extinct. In Montana, the arctic grayling is currenly found in 4% of it’s former range, and most native populations exist in a small area of the Big Hole River near Wisdom, Montana. The severe declines in the lower 48 states are likely caused by a number of factors. First, the arctic grayling is very easy to catch, and populations have likely been overfished by anglers. Secondly, many habitats have been either dammed or diverted. These changes have caused increased silt deposits in lakes, or acted as barriers to moving grayling. Lastly, arctic grayling are easily outcompeted by introduced rainbow and brown trout, which eat young grayling. The arctic grayling is now considered a species of special concern in the state, and populations are closely monitored. Several arctic grayling populations have been introduced in mountain lakes for purposes of sportfishing. Glossary: Adipose fin: a small fleshy fin along the midline of the back behind the dorsal fin. Axillary process: the very small fin attatched to the pelvic fin. Dorsal fin: a fin along the midline of the back, usually midway between the head and tail fin. Pelvic fin: the fin on the underside of the fish nearest the head. Spawn: the act of mating between two fish with the purpose of producing offspring. Keywords: whitefish, salmonid, Prosopium, williamsoni References: Alaska Department of Fish and Game. Wildlife Notebook. Arctic Grayling. http://www.adfg.state.ak.us/pubs/notebook/fish/grayling.php Holton, G. D. and H. E. Johnson. 2003. A Field Guide to Montana Fishes, Third Edition. Montana Fish, Wildlife & Parks, Helena, MT. Montana Fish, Wildlife, and Parks Animal Field Guide. Arctic Grayling. http://fwp.mt.gov/fieldguide/detail_AFCHA07011.aspx Contributor: Allison Greene