Evaluating the Effectiveness of Fyke-Net Sampling to Characterize an Anadromous Rainbow Smelt Population in the Fore River, Massachusetts, USA

Abstract

Rainbow Smelt Osmerus mordax are a small anadromous species that is native to the northwest Atlantic Ocean, and their populations have declined rangewide. A small, mid-channel survey fyke net is annually deployed to collect demographic information on Rainbow Smelt in several rivers in Massachusetts. Understanding the effectiveness of this fyke net for providing representative data on the spring spawning run is essential for accurate population assessment. To evaluate this effectiveness, we deployed an experimental fyke net that spanned the river channel concurrently with the survey fyke net in the Fore River, Massachusetts, from 2009 to 2012. The survey net CPUE increased as the total number of fish increased, but survey net catches are highly variable at lower daily abundances. The differences in the size distributions were slight and only significant for females in 1 of 4 years. The sex ratios were generally the same between both nets. These findings suggest that while fyke nets might not be ideal for monitoring rivers with very small populations and/or in wide river reaches, catches in larger populations should generally reflect the overall population demographics.