Population surveys of the Devils Hole pupfish began in 1972. Population counts since then have been conducted using the same methods, with scuba diving researchers counting fish starting at depths of while researchers above the water count the individuals on the shallow shelf. From 1970 through 1996, the average population was 324. Population highs were recorded in 1980, 1990, and 1995 at counts of 541–548 individuals. Since 2005, the population at Devils Hole has been below 200 individuals, although the population fluctuates depending on the season. Low algae growth and other winter conditions cause spring populations to be 35–65% of the autumn population. The reasons for the decline of the population are unclear. A 2014 study ascertained that the Devils Hole pupfish had a 26–33% chance of becoming extinct in the next twenty years