The pupfish numbers are on the rise!

Cave diving in the Death Valley National Park is not an everyday recreational activity. Twice a year, a team of approved cave divers descend into a protected habitat surrounded by a seven foot chain link fence topped with razor wire. The Devils Hole Dive Team provides a critical piece of data on the survival of an endangered species –a census of the Devils Hole pupfish (Cyprinodon diabolis) population.

Right: Devils Hole Dive Team Row: Steve Cane, Tom Jaskulski, Robert Perotti, Robert Novak, Jonathan Howard, Peter Garcia. Front Row: Zane Marshall and Stan Hilliard. (Death Valley National Park)

The most recent dive occurred on Saturday, October 4, 2008. The day was crisp and clear, with no recorded seismic activity. Global seismic shifts tend to affect water levels at Devils Hole, causing waves on the surface that disturb the algae on the small spawning shelf the pupfish inhabit.

24 hours earlier, the divers gathered at the Death Valley National Park Service office in Pahrump, Nevada for a thorough disinfection of equipment. Disinfection protocols are extremely rigorous – the introduction of a non-native species into Devils Hole could be devastating for this small environment. Thanks to the support of the Dive Rite Ambassador program, hard-to-disinfect equipment items - like Rec Wings and regulators - have been dedicated solely for use in the Devils Hole system.

National Geographic videographers recording the dives of the Devils Hole Dive Team. (Death Valley National Park)

The divers winced on Saturday morning when they slipped on their wetsuits, which had been placed in a deep freeze overnight as a disinfection precaution. Lead Research Diver, Dr. Stan Hillyard of the University of Nevada, Las Vegas, noted at the end of the pre-dive briefing - “careful kicks near that west wall.” The west wall of Devils Hole is covered by an algal mat – the slightest disturbance spreads algal debris, changing this delicate habitat.

A lead team and secondary team, both comprised of one research diver and a safety diver – descend for approximately one hour at a time. After the initial descent, Stan Hilliard inspected crevices and rock surfaces for pupfish in a set pattern that covers four general areas. The secondary team follows the lead team, counting all of the same areas. This protocol is repeated two more times, and on the third dive the researchers also collect information about length of the fish in 5mm increments.

While the divers are performing the underwater count, a topside surface count occurs on the small spawning shelf. Members of the Devils Hole Pupfish Recovery team kneel on a narrow platform and count.

Right: A school of pup fish (Cyprinodon diabolis) (Death Valley National Park)

There was a hushed excitement after the first count. The numbers were promising to be better than the previous year. The official pupfish count this year is 126, a 37% increase over the Fall 2007 count, the highest number recorded since 2004. The pupfish had been in a gradual decline, but recent efforts by a multi-agency and university team of biologists to supplement natural food supplies and monitor Devils Hole appear may be contributing to the pupfish numbers.

Videographers from National Geographic followed the dive team, and one of the dives included a National Geographic diver and a dive team safety diver. Look for the underwater footage in the Spring/Summer lineup of National Geographic specials.