Coarse-scale relationships between seabirds and zooplankton off south-eastern Tasmania

Observations were made of seabird and zooplankton distribution in the water s adjacent to south-eastern Tasmania to examine correspondence at coarse sc ales (tens of kilometres). The distribution of seabirds was related mainly to changes in the water depth (and distance from land) over the length of t he transect, whereas the distribution of zooplankton related to temporal ch anges. Significantly different associations of seabird species occurred in Storm Bay (mainly species breeding within the bay), and over the shelf-edge (with many non-breeding species dominant). Zooplankton diversity varied du ring the study, being greatest at the beginning (May) and end (September) o f the study. Little correspondence was found between the distribution of se abirds and zooplankton at the community level, but there were significant r elationships for several species, such as diving petrels and gannets. The l ack of an overall correspondence between seabirds and zooplankton may have been due to the patchiness of seabird and zooplankton distribution, limits to the requirements of seabirds to find maximum prey densities (instead onl y needing to find 'enough'), the lack of certainty about whether seabirds w ere foraging when observed, and behavioural interactions among seabirds.