Age, growth, and reproduction of leatherside chub ( Gila copei )

The leatherside chub (Gila copei) is a small cyprinid native to eastern and southern areas of the Bonneville Basin of Utah, Idaho, and Wyoming, to Wood River, Idaho, and to regions of the Snake River, Idaho and Wyoming, above Shoshone Falls (Baxter and Simon 1970, Simpson and Wallace 1982, Sigler and Sigler 1987). Gila copei is currently listed as a candidate for federal protection under the Endangered Species Act. Conservation efforts for G. copei would benefit from accurate life history data, yet the life history of G. copei is not well known. This species was thought to live less than five years (Sigler and Sigler 1987). Based on bright coloration of males and abdominal distension in females, Sigler and Miller (1963) concluded G. copei spawns between June and August. Using similar coloration criteria on males from Sulphur Creek, WY, Baxter and Simon (1970) suggested breeding occurred in late summer; Simon (1951) found females distended with eggs in early August. Other than these few observations, no data on age, growth, or reproduction are available. We present data on age, growth, and reproduction of leatherside chub from central Utah; these data were generated as a first step to understanding and protecting this potentially threatened, endemic fish species.