A study of sampling strategies for estimating growth parameters in fish populations

Abstract

The effects of different sampling strategies for age and growth studies and for the estimation of growth parameters from size-at-age data were investigated using simulated age-structured populations of two fish species representing different life history characteristics. One species type was a small pelagic with relatively fast growth, small size, high mortality, low longevity and is representative of r-strategists. The second case was a K-strate-gist (lutjanid/sparid) type with relatively larger size, slower growth, greater longevity and lower mortality. Three different sampling strategies were evaluated: (1) simple random sampling; (2) proportional allocation; (3) fixed allocation. Overall, there is no best sampling strategy in all situations. Proportional allocation tends to show smaller parameter variability. Overall, there seems to be no advantage in fixed allocation in relation to proportional allocation or even simple random sampling.