| Scientific Name | Gila nigra |
| Category | F |
| Taxon | Fish |
| Climate Change Vulnerability Score | Extremely Vulnerable |
The Headwater Chub (Gila nigra) is a small (males: 50 cm [20 in], females: 10-18 cm [4-7 in]) fish that occurs in the Gila River basin in Arizona and New Mexico. It prefers pools and runs near cover objects or deep water in the headwaters of rivers and creeks. It is highly omnivorous, feeding primarily on invertebrates and algae and occasionally eating detritus, vegetation, and fish. Recent taxonomic work suggests that the Headwater Chub in New Mexico may be the same species as two other limited-distribution fishes of the lower Colorado River drainage, the Gila Chub (Gila intermedia) and Roundtail Chub (Gila robusta). The Headwater Chub will experience a high degree of climate exposure and has a low adaptive capacity. Overall, it has a Climate Change Vulnerability Index ranking of Extremely Vulnerable under both Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 Scenarios. The Headwater Chub’s climate change vulnerability is impacted by factors related to distribution and abiotic niche, which influence its ability to shift in space and respond to climate change impacts. It is also impacted by barriers, land-use changes and other anthropogenic and biologic factors that could increase the effects of climate change.



