Trip report - Biology project, Carroll Cave

10 March 2007

Time in: 11:45am
Time out: 6:45pm

Participants:
Bill Gee - Trip leader
Craig Hines
Shawn Williams
Andy Isbell

This trip was planned to go out past the breakdown pile in upper Thunder River and do a fish count to the terminal waterfall. Our plans were busted when Doug Feakes got sick and could not make it. With only three people we could not safely do a trip that far out in the cave. Fortunately we were able to change our plans. We didn't get the trip we wanted, but we did get some biology work done.

Rick Hines had a trip going the same day for the landowner's attorney and a land appraiser. We "borrowed" Craig Hines from that trip. Due to Craig's schedule we were not able do a long trip. Instead, we helped Rick with his landowner trip. After the visitors were safely out of the cave, the four of us set out for a fish count in the near section of upper Thunder River.

We left the ladder at 3:15pm and started counting fish at the stilling well. This is just below the ladder. The section of the river from there down to Thunder Falls had been pretty well silted over by the traffic, so we would not have been able to do anything useful. We proceeded with a fish count up to the Round Room, then returned. We were climbing the ladder at 6:20 and out of the cave by 6:45.

On this fish count we introduced a new set of data to collect. I had a short 6 inch ruler and Andy brought some calipers. With a couple of aquarium nets we caught a number of fish and measured how long they were. After some random sampling at the start, we decided to measure every 4th fish.

The measurement proved to be a bit more difficult than we thought. Blind cave fish move surprisingly fast when they sense a net coming, and they wiggle a lot when in the net. Eventually Andy, Shawn and Craig worked out a method of holding the fish from under the net using a flat hand while another person did the measurement. This gave us measurements about as close as can be had on live specimens.

Most of the measurements were done with the calipers. Andy tried a digital caliper first and it worked well until it got wet. He then switched to a simple plastic caliper for the rest of the trip. We measured two fish with the plastic ruler. It did not seem to make much difference which tool was used. The measurements were pretty much the same both ways.

Stilling Well - 3:15

We counted 15 fish from the stilling well to UR1. We caught and measured 5 fish. The lengths were 28mm, 39mm, 40mm, 48mm and 26mm.

UR1 - 3:53

We counted 33 fish from UR1 to UL2. We caught and measured 8 fish. The lengths were 42mm, 55mm, 42mm, 42mm, 45mm, 41mm, 58mm and 51mm.

UL2 - 4:40

We counted 13 fish from UL2 to Flat Rock Falls. We caught and measured 3 fish. The lengths were 46mm, 45mm and 49mm.

Flat Rock Falls - 5:00

We counted 6 fish from Flat Rock Falls to the Round Room bio marker. We caught and measured one fish at 51mm. While at Flat Rock Falls we did a quick isopod count. We counted 48 isopods and 1 planaria. We only spent about 5 minutes doing this count, so it cannot be considered thorough.

Bio marker at the Round Room - 5:20.

Total of 67 fish counted. We caught and measured 17 fish. Shortest was 26mm and the longest was 58mm. Average was 44mm.