An Attempt to Determine Abundance and Distribution of Migrating Skeena River Salmon Stocks By Acoustical Means

Echo surveying is one of the newer techniques for estimating the abundance and distributional patterns of fish stocks and its potential seems promising as it is a convenient, economical and effective way of collecting information on underwater objects. Stock assessment by acoustical means was initiated locally by Tester (1943). More recent studies, Richardson et al. (1959) and Cushing (1968) have shown that accurate indices of abundance and distributional patterns can be obtained with echo sounders. Most studies to date have dealt primarily with demersal and pelagic fish stocks. The present paper deals with migrating fish, ascending a shallow river, which are potentially more difficult to enumerate by acoustical means.