Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
Comments: Information is not available from Asia, and occurrences are not tracked in North America. Therefore, the number of occurrences can only be estimated based on collection maps and natural heritage programs state and provincial ranks. Lee et al. (1980) and the Texas Natural History Collection Index to North American Freshwater Fishes (1998) mapped approximately 110 collection sites. Heritage program ranks of apparently secure and secure in California, British Columbia, Alaska, and Washington suggest a large number of occurrences (probably more than 100).