Empirical results on precision - effort relationships for acoustic surveys
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http://hdl.handle.net/11250/104571Utgivelsesdato
1989Metadata
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Repeated echo integrator surveys using a rather dense survey grid were
performed in areas where the effect of fish migration was assumed to
be insignificant. Relative estimates of fish abundance representing
different survey grid densities were calculated by using observations
along all transects, each second transect, each third transect and
so on. The "degree of coverage" of an area was defined as the ratio
between "sailed" distance and the square root of the total area
covered. Coefficients of variation of the relative estimates were
calculated for each degree of coverage. Observations and results for
different areas are compared and discussed, and curve fit between the
coefficient of variation and the degree of coverage for the
observations are presented. Coefficients of variation estimated from
the inter-transect variation are compared with the observed ones.