Blue chub
Encyclopedia
The blue chub Gila coerulea is a cyprinid
fish
found in the Klamath River
and Lost River
drainages of far northern California
and southern Oregon
.
Relatively slender among chubs, it has larger eyes than most and a terminal mouth that extends back nearly as far as the forward edge of the eye. Color is a nondescript dusky shade on the back and silvery on the sides; the name comes from the males at breeding time, whose snout becomes noticeably blue, along with orange tinges on the sides and the fins. There are 9 rays in the dorsal fin, 8-9 in the anal fin, and 14-17 in each pectoral. Length ranges up to 41 cm.
Blue chubs have a varied diet, including both aquatic and terrestrial insect
s, crustacean
s, and filamentous algae. They occur in a variety of habitat
s in their range; abundant in lakes, they are also found in streams and rivers. In Upper Klamath Lake
, they generally prefer rocky margins and open water to marshy shores, while along Boles Creek, they are most abundant in shallow weedy reservoirs.
Spawning extends from May through August, typically over shallow gravelled areas, of depths of 0.5 meters or less. Each female is attended by two or more males, who agitate the water and thrust against her while she lays eggs
in masses that adhere to shore
line rocks. (C. R. Hazel observed some males pushing females entirely out of the water in their excitement.)
Although not officially listed as a threatened species, and common within their range
, Moyle says that there is cause for concern; the range is geographically limited, and the population dropped in the 1980s and 1990s, due to a combination of drought
, pollution (agricultural runoff), and pressure from introduced fathead minnow
s.
Cyprinid
The family Cyprinidae, from the Ancient Greek kyprînos , consists of the carps, the true minnows, and their relatives . Commonly called the carp family or the minnow family, its members are also known as cyprinids...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
found in the Klamath River
Klamath River
The Klamath River is an American river that flows southwest through Oregon and northern California, cutting through the Cascade Range to empty into the Pacific Ocean. The river drains an extensive watershed of almost that stretches from the high desert country of the Great Basin to the temperate...
and Lost River
Lost River (California)
Lost River begins and ends in a closed basin in northern California and southwestern Oregon in the United States. The river, long, flows in an arc from Clear Lake Reservoir in Modoc County, California, through Klamath County, Oregon to Tule Lake in Siskiyou County...
drainages of far northern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and southern Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
.
Relatively slender among chubs, it has larger eyes than most and a terminal mouth that extends back nearly as far as the forward edge of the eye. Color is a nondescript dusky shade on the back and silvery on the sides; the name comes from the males at breeding time, whose snout becomes noticeably blue, along with orange tinges on the sides and the fins. There are 9 rays in the dorsal fin, 8-9 in the anal fin, and 14-17 in each pectoral. Length ranges up to 41 cm.
Blue chubs have a varied diet, including both aquatic and terrestrial insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, and filamentous algae. They occur in a variety of habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s in their range; abundant in lakes, they are also found in streams and rivers. In Upper Klamath Lake
Upper Klamath Lake
Upper Klamath Lake is a large, shallow freshwater lake east of the Cascade Range in south central Oregon in the United States. The largest freshwater body in Oregon, it is approximately 20 mi long and 8 mi wide and extends northwest from the city of Klamath Falls...
, they generally prefer rocky margins and open water to marshy shores, while along Boles Creek, they are most abundant in shallow weedy reservoirs.
Spawning extends from May through August, typically over shallow gravelled areas, of depths of 0.5 meters or less. Each female is attended by two or more males, who agitate the water and thrust against her while she lays eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
in masses that adhere to shore
Shore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...
line rocks. (C. R. Hazel observed some males pushing females entirely out of the water in their excitement.)
Although not officially listed as a threatened species, and common within their range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
, Moyle says that there is cause for concern; the range is geographically limited, and the population dropped in the 1980s and 1990s, due to a combination of drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
, pollution (agricultural runoff), and pressure from introduced fathead minnow
Fathead minnow
The fathead minnow , is a species of temperate freshwater fish belonging to the Pimephales genus of the cyprinid family. The natural geographic range extends throughout much of North America, from central Canada south along the Rockies to Texas, and east to Virginia and the Northeastern United...
s.