7611 - Laserfiche WebLink

Home Browse Search

- leclaution's assigned stndy area ranged from river d le 16.2 of the San Juan River to reference mile -2.0 within Lake Powell (see snap). All habitats within these limits were sampled with the appropr- isle Gear during at least one of the three sampling periods. Procedures Fisheries Data Collections Data collection procedures described in the San-Juan River Rare and Endangered Fish Work Statement were followed as closely as possi- ble. Since much of the area sampled was reservoir or a sizture of river/reservoir habitat, however, sos~e fish collection setbods were modified to ensure sampling effectiveness. All electrofishing sampling was accomplished using a motorized 17 foot Jon Boat equi pd with a Coffelt Hodel Variable Voltage Pulsator (VVY 15). The positive electrode array varied from four to sin Janglers per boom depending on existing water conductivity. Pulsed direct current was used exclusively. Since personnel were base-carped downstream of the riverine section of the study area, all electrofishing efforts required initial upstream negotiation of the river. Sand bars from sediment deposition, swift water velocity during higher river flow and low water depth during lower flow significantly inhibited both upstream travel and downstream sampling. These factors dictated the extent of the area electrofished and duration of sam- pling. The data reflect these limitations in basically two ways: where sampling began and ended and the area within the river that could be sampled. 4