Thursday, June 30, 2011

Interesting Animals: Devil's Hole Pupfish

Devil's hole pupfish (Cyprinodon diabolis)
These little fish are found in only one small, water-filled cave in Death Valley: Devil's Hole. They forage exclusively on a small rock ledge in the pool, and their population is only 36 individuals. Since the pool is found in such an arid region, there is great concern that the pool could dry up, either naturally, or due to nearby agriculture depleting the water that feeds the pool. These little fish were even involved in a 1976 supreme court case (Cappaert vs. U.S.) that ruled to prevent removal of too much water from Devil's Hole. The IUCN Red List currently has them listed as Vulnerable, though they are in need of being assessed again. 

Devil's Hole
The pupfish are under constant watch (see the camera on the ledge at right), and there is an attempt to create a stable captive population in the event that something happens to Devil's Hole. Some would say "Why save these little fish? It wouldn't make any difference if they weren't there anymore." However, in many ways the conservation of these pupfish is a small-scale exercise in trying to increase the numbers of an endangered species. Indeed, in 1988 these fish were listed as Endangered by the IUCN Red List and their numbers did manage to rebound and stayed fairly steady for many years. Since then, though, they have dropped again and the US still classifies them as Endangered.

There is concern as to how many times the population can shrink and then rebound. Each time this occurs, genes are lost through the bottleneck effect, and can lead to a spiral downward to extinction if the loss of genes no longer allows for the fish to be able to stand environmental changes.

Images used are either copyright-free or under a Creative Commons license at Wikimedia Commons.

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