Comparison of Three Larval Fish Sampling Methods in Shallow, Complex, Wadeable Rivers

Title:  Comparison of Three Larval Fish Sampling Methods in Shallow, Complex, Wadeable Rivers

Format:  Poster

Authors:  Hanks, R. Daniel.  West Virginia University; 864-200-8167; rhanks@mix.wvu.edu

Hartman, Kyle J.  West Virginia University; 304-293-4797; hartman@wvu.edu

Presenter:  R. Daniel Hanks

Student Presentation:  No

ABSTRACT

To document fish reproduction in streams, larval fish are often sampled using a variety of methods.  High variability in commonly used techniques (e.g., light traps, pumps, sweep nets, etc.) is in part due to the limited ability of these techniques to effectively capture all species during early life stages and is often exacerbated by the diversity of fish reproductive modes and the variable distribution of larval fish.  Due to the difficulty in sampling larval fish in shallow, structurally diverse streams the efficacy of a novel active sampling method, a spot-and-sweep technique coupled with an adaptive cluster sampling approach, was evaluated relative to drift nets and light traps during daytime and nighttime hours.  We evaluated these methods based on total catch, size distribution, number of taxonomic groups, catch per unit effort (CPUE), and coefficient of variation (CV) for both day and night sampling periods.  Sweep nets collected more larvae (257/281 day/night individuals) than drift nets (2/40 day/night individuals) and light traps (0/81 day/night individuals).  CV was lower for sweep nets (94/129% day/night) than drift nets (424/159% day/night) and light traps (NA/213% day/night).  Richness for the three methods will be analyzed and discussed.