On Saturday, May 10, 2003 (while Dan Austin, Brian Borton, and Matt Goska
worked on the entrance), four of us did another bioinventory from Thunder
Falls to the Round Room. We also took note of the number and
characteristics of 16 different riffles upstream, for animal census
studies later. Some of these are now marked with white-and-red
polka-dotted tape, labeled "BIO (#)". At the Round Room we checked on
some bait that had been left in the cave a couple weeks prior.
Members of our party included Bill Gee, Andy Isbell, Rita Worden, and
myself. We made our way through Matt & Brian's jungle of wooden forms
and started counting fish at Thunder Falls by 1000 hours.
Thunder River had been about 12 inches deeper recently, but had dropped
to about 5 inches above normal by the time we were there. The current
was noticeable and the water's clarity was worse than we'd seen it in
April. Foam was present in some of the backwaters and eddies. Despite
these difficulties, we feel our total cavefish count of 38 does represent
a real (and at least temporary) decline in cavefish numbers upstream.
Weak swimmers, many fish had probably been swept downstream in the days
before our census.
Isopods were also much less frequent, usually found on the protected
underside of rocks in swift water rather than milling about on the upper
surface. No cavesnails were found. We took several opportunities to
check rocks in pools, to be sure we weren't ignoring animals in deeper,
less oxygenated conditions, but no invertebrate life was observed outside
riffle habitats.
At the Round Room, on April 12, we had seen several interesting "bugs" at
an old campsite. This was where Terry Sherman recently left a couple
bait stations out for us in hopes that it would draw more troglobites.
This month we returned to the site to find the troglobites much scarcer,
and the bait covered with Ptomophagus beetles instead (about 30!).
Ptomophagus beetles are pigmented and not especially cave-adapted. I had
always associated them with shorter caves and was surprised to find so
many so far back in Carroll.
On the way out, someone noticed a Northern long-eared bat that had
recently died, near the bottom of the shaft. We all agreed that the
trail markers had looked really good, overall. Climbing the ladder,
everyone was on the surface by 1700 hours or so.
Many thanks to those who came to help.
In the future I'll be doing random samples for "bugs" at riffles along
upstream Thunder River. More terrestrial invertebrate traps will likely
be placed at two or more locations. I'm also acquiring a macro scope, a
collector's permit, and a good thermometer soon. Before July, I'd like
to come up with some way to measure turbidity in the stream (without
buying a high-dollar instrument), and to price a depth gauge that might
be placed at the Thunder Falls pool.
Respectfully,
Lawrence Ireland