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We investigated the effects of variation in underwater visibility on the accuracy of diver counts of rainbow trout Oncorhynchus mykiss in the Salmo River, British Columbia, over a 3-year time period. A four-man team of divers, drifting in a downstream direction, made periodic counts of trout along a study reach in which radio-tagged fish that had also received a visual mark were present. Observer efficiency of divers (number of tags seen relative to the number known to be present) was significantly related to horizontal underwater Secchi disk visibility during 2002 and 2003 but only poorly so for the first year of the study in 2001. Overall, horizontal visibility in the 3 years' combined data set was significantly related to observer efficiency, explaining 62% of the variation. Diver counts of untagged trout confirmed these patterns. Diver counts of trout greater than 30 cm and greater than 40 cm showed precise, significant relationships with horizontal visibility for both 2002 and 2003. Horizontal visibility changes explained 94% and 93% of the variation in counts of trout greater than 30 cm and greater than 40 cm, respectively, in 2002 and 94% and 87% of the variation for the same size categories in 2003. The poor-quality, nonsignificant relationships between counts of trout and visibility in 2001 were consistent with the poor observer efficiency relationship for that year as estimated from the observations of the radio-tagged fish. Taken together, these poor-quality relationships for the first year of the study point to either crew inexperience or some other factor(s) as an important source of error in addition to water clarity. [ABSTRACT FROM AUTHOR]

Assesses the effectiveness of a fish migration barrier in the Salmo River, British Columbia by means of radio telemetry and Floy tagging. Purpose of the barrier; Background on the study site; Total number of suckers and pikeminnow observed in the study.

The article discusses the history of otolaryngology at the University of British Columbia (UBC). The university was founded in 1908 by an act of the provincial legislature. With the establishment of a Faculty of Medicine at UBC, Dr. Gordon Francis was appointed associate professor and head of the Division of Otolaryngology in 1951. Undergraduate and graduate teaching in otolaryngology at UBC are also discussed.