Inter-Research > MEPS > v122 > p107-113  

MEPS 122:107-113 (1995)  -  doi:10.3354/meps122107

Estimation of the size of a coral reef fish population

Gaudian G, Medley PAH, Ormond RFG

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 emperor 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 census data as indices of abundance to obtain 2 independent estimates of population size, which were found to be similar. These estimates further converged if the models included an estimate of the immigration rate into the fished population. The present study demonstrated that depletion experiments provide valuable information on coral reef fish populations, particularly for fisheries.


Depletion experiment · Population size · Coral reef · Stock assessment · Visual census · CPUE


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