A Modified Box Trap Design for Sampling Emigrating Salmonid Smolts from Small Streams

Abstract

A box trap was constructed and used to collect juvenile steelhead Oncorhynchus mykiss in Spooner Creek, Erie County, New York, during the spring of 2000 and 2001. The trap was designed for use in streams with short waterfalls. It was utilized for approximately 70 d each spring and trapped 552 and 1,702 steelhead juveniles in 2000 and 2001, respectively. Approximately 5–75 steelhead per night were collected with negligible mortality, and streams were effectively sampled in discharges below 35 ft³/s. Trap efficiencies averaged 51% and 63% in 2000 and 2001, respectively. Problems were encountered during high-water periods, as high water caused the trap to become submerged and useless once the windows were plugged with forest litter. However, these episodes were rare. The modified box trap design presented here proved effective in a variety of conditions and should provide fisheries scientists an effective tool for sampling juveniles in smaller streams.