A Hot Time in Devils Hole
Does diving in bathtub water conditions sound alluring? Warm water has always attracted divers, however this team shows us how challenging "warm" water can really be. by Stan Hillyard and Zane Marshal
Zoom+ Climbing down to the water in Devil's Hole
In July 2009 the Devils Hole Dive Team was called upon by the National Park Service to conduct a series of dives to answer important questions about the monitoring methods and status of the Devils Hole pupfish, which occurs in the most restricted habitat for any fish in the world. The team made three dives per day over a four day period to determine if the estimates of the population size varied from day to day, from morning to afternoon and between counters.
Diving in Devils Hole in July presents major challenges due to the extreme environmental conditions on the surface, and the remoteness and primitive nature of the site. During the July research effort, dehydration and hyperthermia were major concerns because daytime maximal temperatures ranged from 111 F to 116 F in the shade and winds, which accelerate dehydration, often exceeded 15 mph. These conditions feel similar to standing in front of a blast heater and obviously must be dealt with to ensure the health and safety of the team. Given that there are no permanent shade or wind-blocks on site, team vehicles were positioned to provide some refuge from the wind and a tarp was tied to the vehicles to provide shade for the divers during surface intervals. However, the vehicles and tarp provided only temporary refuge as team members had to get out of the shade to configure gear and access Devils Hole by climbing down a steep ladder and rocky slope (see photo). Remember the temperature here is over 110 F, and by the second dive everything is hot to the touch!
Zane, Tom, Stan and Peter in the "cool" 93 degree water - ready for a dive" class="thickbox">Zoom+ face="Times New Roman">Zane, Tom, Stan and Peter in the "cool" 93 degree water - ready for a dive
Zane, Tom, Stan and Peter in the "cool" 93 degree water - ready for a dive" />
The dives extended down to over 100 feet and averaged an hour in length. Even though the team ascended slowly while counting fish, 5 minute decompression stops were made at 15 feet and a ten minute oxygen wash was used during the surface interval to minimize residual nitrogen accumulation. The 93 F water that normally feels warm was pleasantly cool after climbing down from above. The second photo shows Ambassadors Zane Marshall, Tom Jaskulski, Stan Hillyard and Peter Garcia ready to go. The third photo shows Stan, Zane, Tom and Peter during an oxygen wash, in the shade at over 110 F.
Based on military calculations for desert warfare, we figured that team members lost about one half liter of fluid per hour on the surface in addition to one liter per dive breathing on SCUBA. A typical day began at 7 AM and we finished at about 3 PM, 8 hours or about 5 or 6 liters of fluid loss. Needless to say we had to drink this much fluid during the day. Tom Jaskulski, the DSO for the team, was constantly telling us to keep hydrated, and the National Park Service provided all the necessary fluids. In a later article Tom will describe in more detail the safety concerns of our diving activities at Devils Hole.
Stan, Tom, Zane and Peter during a ten minute oxygen wash.
The result was the discovery that the fish avoid the shallower habitat during mid-day, where water temperatures may approach 96 F. This new information will help managers understand how pupfish utilize their limited habitat and how such things as Global Climate Change may affect the future of the species.
The Devils Hole Dive Team is committed to providing valuable information to help preserve this very rare fish species, and our Dive Rite gear helps us to safely accomplish our mission, even in extreme conditions.