Practical acoustic surveying

Abstract

The acoustic estimation of fish abundance has much in common with other survey methods used in fisheries research. It involves the collection of data from the area inhabited by the species of interest, and the analysis of acoustic and other records to provide whatever information is required about the fish in the area at the time of the survey. The usual intention is to determine the size of a particular ‘stock’ of fish. The stock is defined by the needs of fishery management, and it is not the same as the biological concept of a ‘population’ (Gulland, 1983). Stocks are often defined in terms of the fish resident within artificial boundaries, e.g. national fishery limits, thus excluding any part of the relevant population that is located elsewhere.