PRRIP 2008-2009 Interior Least Tern and Piping Plover Monitoring and Research Report

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temperature, turbidity, depth, flow, benthic substrate (sand, clay /silt/organic, or gravel), and habitat class (main channel, secondary channel, braided/dendritic channel). We then placed a 50 -m float line 2 in from the sample point (perpendicular to the current) to guide the direction and distance of the sampling path. We began trawls at the sampling point and 2 people space 3 in apart towed it downstream parallel to the float line at a speed that was slightly faster than the river current. If the trawl -net became inverted while collecting a sample, we discarded the sample, recorded the attempt, moved to the other side of the float line, and collected our sample. Once completed, the trawl mouth was held out of the water and we processed the sample at a nearby sandbar or shoreline not currently used by interior least terns or piping plovers. All captured fish were identified to species, measured, and released as quickly as possible. We used fish identification guides and taxonomic keys to identify fish to species. When large samples of fish were caught, we placed fish in a bucket of river water prior to handling to reduce the chance of mortality. Once we finished sampling at the foraging location, we used a two - column random number table to modify the Northing and Easting of GPS point collected at observed foraging site and generated random locations. We used a GPS unit to navigate to randomly generate locations and sampled the area as described for foraging locations. When randomly generated locations were not within the same habitat class as the foraging location, were unsafe to sample (e.g., excessive flows or depths > 1.5 m), or when sampling path overlapped a previously sampled path from that day, we recorded the unsuitable random location and selected the next randomly generated location from the table. Sandpit Sampling: We used a canoe to navigate to observed- foraging locations when on sandpit ponds. In order to maintain our position on windy days, we deployed an anchor as far up -wind as possible and scoped the anchor line out until we reached the foraging location. Similar to river sampling, we collected a GPS location and data on water temperature, turbidity, depth, and benthic substrate. We deployed a minnow trap by driving the stake ends into the substrate ensuring the lead pointed toward the center of the pond when depths were <0.75 in or floated at the surface for locations with depths >0.75 m. When minnow traps were floated, we ensured they were secured with an anchor; line length was slightly longer than the depth of water to prevent trap from moving if the wind changed direction. We record time the trap was deployed and left traps in place for 24 hours. After 24 hours, we retrieve the traps, recorded the collection time, and processed samples as with river samples. PRRIP 2008 -2009 Tern /Plover Report Page 31 of 42