Small-scale variation in reproduction and abundance of greentail prawn, Metapenaeus bennettae Racek and Dall, 1965

Abstract

Sampling on a single night or day within a month is common in studies of reproduction and abundance of aquatic invertebrates, but patterns from month-to-month may be confounded by variability at smaller time-scales. We used hierarchical sampling in two estuaries to test the hypothesis that temporal variability in reproductive condition, relative abundance and size-structures of populations of Metapenaeus bennettae Racek and Dall, 1965 would be greater at the larger scales of months and seasons than at smaller scales of weeks and nights. In both estuaries, variation in the proportion of mature/ripe females and mean abundance of M. bennettae was often largest at the temporal scales of nights and weeks, but variation in the size-frequency distributions was generally greater at the scale of months and seasons. Our results demonstrate that future studies on any species with the potential for high temporal variability in reproduction and population structure, like penaeids, should incorporate or examine the need for small-scale temporal sampling.