The last confirmed specimens of "C. n. calidae" were collected on February 2, 1970, and the subspecies was probably extinct by the next year. Further surveys in 1972 and 1977 returned no examples of the fish. In 1978, United States Fish and Wildlife Service announced that it was considering delisting the fish, with Assistant Secretary of the Interior Robert L. Herbst calling the loss "totally avoidable" and saying, "The human projects which so disrupted its habitat, if carefully planned, could have ensured its survival." In 1981, after an exhaustive search of over 40 locations, the Fish and Wildlife Service officially declared the fish extinct. It was the first animal removed from the provisions of the 1973 Endangered Species Act as a result of its extinction.