News of the Week

June 20, 2014

A Service of the Oklahoma Department of Wildlife Conservation

BIOLOGISTS SAMPLE SOUTH CANADIAN RIVER FOR THREATENED FISH

Wildlife Diversity biologists with the Oklahoma Department of Wildlife Conservation recently teamed with the U.S. Fish and Wildlife Service to collect samples of the federally threatened Arkansas River shiner (Notropis girardi). Biologists were able to sample seven of the 10 established sites along a 300-mile stretch of the South Canadian River from Cheyenne to Calvin over two days. Recent rains across the state created unsafe conditions along the lower portion of the river, suspending sampling efforts at several sites.

The Arkansas River Shiner is found in the main channels of large, sandy-bottomed rivers and streams. 
The Arkansas River shiner is a slim silver minnow with a small head and rounded snout. A v-shaped mark is usually present at the base of the tail. Maximum length for this shiner is 2 inches. First described in a 1926 survey of the Cimarron River, this fish species has since disappeared from over 80 percent of its historic range.

Matt Fullerton, endangered species biologist for the Wildlife Department, said the species is now almost entirely restricted to the Canadian River in Oklahoma, Texas and New Mexico. The Arkansas River shiner typically spawns in May, June and July, but can spawn into August if adequate flow exists. Spawning appears to coincide with rains providing increased river flow; however, spawning occurs throughout the summer with adequate flow. Eggs drift with the current and develop as they move downstream. U.S. Fish and Wildlife Biologist Daniel Fenner said, "Eggs and larvae need approximately 130 miles of free-flowing river to complete their development process." Throughout the Arkansas River shiner's 18-month life span, individuals move upstream where they eventually spawn to complete the species' life cycle. Habitat destruction and modifications to river flow such as dam construction and water withdraws (ground and surface water) are the principle reasons for the shiner's decline. When eggs reach an impoundment, they will sink to the bottom of the water column, and fry development will cease. Without adequate flow upstream of these dams, the shiner may not be able to move upstream far enough to successfully reproduce.

Wildlife Diversity biologists use a seine to sample the fish community of the South Canadian River. 

To survey Arkansas River shiners and other fish species, biologists used a 4-by-15-foot mesh net, or seine. The lower portions of seines are weighted with a lead line so that fish can't escape underneath the net as it is pushed through the water. When the team reaches the end of the sampling area, one biologist pivots at the water's edge while the other swings toward the bank. The seine is then lifted out of the water, and biologists identify their catch. Fifteen sampling areas were completed at each of the seven sample sites, for a total of 105 seine hauls.

Curtis Tackett, wildlife diversity biologist for the Wildlife Department, mentioned sampling for Arkansas River shiners was successful at sites with more desirable habitat. Tackett also commented, "In the absence of Arkansas River shiners, other species such as red shiners and sand shiners were abundant."  Additional sampling for the Arkansas River shiner will occur in October.