Fish diversity and discharge rates in Bornean rainforest streams

Abstract

TFE Field course 2020 group project. Recorded the fish communities and discharge rates along 100m transects on 7 rainforest streams in and around the SAFE project site in Sabah, Borneo. - Stream discharge: this was estimated using gulp-injection dilution gauging using table salt as the tracer. An Omega CDH-SD conductivity logger was used to record stream conductivity at 1 second intervals. The conductivity meter was set up at 0m on the stream's transect, it was left to stabilise and then 50m upstream 200g of salt was injected. Conductivity was monitored for a peak followed by a return to original levels. - Electrofishing: For each stream fishes were caught and released using three-pass electrofishing (model EFGI 650 electrofisher). The fishing occurred along a 100m transect with fish net blockades set up at each end to prevent immigration and emigration of fish during the sampling period. Electrofishing occurred in 3 phases, the same transect line was repeated with different voltages. Voltage varied per stream based on its conductivity and the recommended guidelines provided by SAFE. Fishes caught were identified to species level following the fish identification guide provided by SAFE and length of fishes was measured using a ruler. The data collected was used to estimate fish biodiversity and stream discharge rates in R.

TFE Field course 2020 group project. Recorded the fish communities and discharge rates along 100m transects on 7 rainforest streams in and around the SAFE project site in Sabah, Borneo. - Stream discharge: this was estimated using gulp-injection dilution gauging using table salt as the tracer. An Omega CDH-SD conductivity logger was used to record stream conductivity at 1 second intervals. The conductivity meter was set up at 0m on the stream's transect, it was left to stabilise and then 50m upstream 200g of salt was injected. Conductivity was monitored for a peak followed by a return to original levels. - Electrofishing: For each stream fishes were caught and released using three-pass electrofishing (model EFGI 650 electrofisher). The fishing occurred along a 100m transect with fish net blockades set up at each end to prevent immigration and emigration of fish during the sampling period. Electrofishing occurred in 3 phases, the same transect line was repeated with different voltages. Voltage varied per stream based on its conductivity and the recommended guidelines provided by SAFE. Fishes caught were identified to species level following the fish identification guide provided by SAFE and length of fishes was measured using a ruler. The data collected was used to estimate fish biodiversity and stream discharge rates in R.