A Lightweight Modification of the McNeil Core Substrate Sampler

ABSTRACT

The McNeil core substrate sampler is widely used for quantitative bulk sampling of streambed sediments, but the large size and heavy weight of the standard-sized device limits its utility for sampling substrates in remote locations. We designed a lightweight modification that employs a 19-L plastic bucket as a collection basin yet retains the standard core tube diameter of 15 cm. The modified sampler weighs about one-third of the standard-sized McNeil sampler (3.9 kg versus 11.5 kg) yet is sufficiently robust that insertion of the core tube into the streambed is readily achieved. The modified sampler enhanced sampling efficiency and facilitated increased sample sizes for substrate sampling of rainbow trout (Oncorhynchus mykiss) redds during a 170 km-long survey of spawning tributaries.