The present study monitored a fish population before and after fishing
within a marked area. Visual census counts along transects were used
to estimate fish abundance inside and around the fishing area. The emp
eror Lethrinus borbonicus made up 64% of fish in terms of numbers and
44% of the catch in terms of weight. As fishing progressed, the catch
per unit effort (CPUE) of L. borbonicus declined. Visual census counts
of L. borbonicus were lower after fishing both inside and outside the
fishing area. Linear models were used to calibrate CPUE and visual ce
nsus data as indices of abundance to obtain 2 independent estimates of
population size, which were found to be similar. These estimates furt
her converged if the models included an estimate of the immigration ra
te into the fished population. The present study demonstrated that dep
letion experiments provide valuable information on coral reef fish pop
ulations, particularly for fisheries.