Quantitative Comparison of Seining and Underwater Observation for Stream Fishery Surveys

Abstract Species occurrence and relative abundance, as determined by direct observation (by snorkel divers) and by seine survey, were compared. Occurrence was compared for a single snorkel survey vs. collections made during 1 year, 3 months, and 1 day. At least as many species (and usually many more individuals) were identified during the snorkel survey as during the seine survey; however, not all species were identified by both methods. Species relative abundance, as judged by seine collections, may be biased toward the smaller species.