ASFB Home > The effects of spatial and temporal factors on the abundance of seven key finfish species along south-western Australia.

The effects of spatial and temporal factors on the abundance of seven key finfish species along south-western Australia.

Suzanne Ayvazian and Henry Cheng

Department Of Fisheries Western Australia, NORTH BEACH, AUSTRALIA

THEME: ASFB

The fully exploited estuarine and coastal finfish stocks in south-western Australia support small scale commercial fisheries and an expanding recreational fishing sector. King George whiting, yellow fin whiting, Australian herring, Australian salmon, yellow eye mullet, sea mullet and tailor are the key species concerned. In common with many small scale coastal fisheries across Australia, stock monitoring information necessary for management must be informative and cost effective. A fisheries independent survey based recruitment index for these seven species has the potential to provide an ongoing stock monitoring system. As a part of the development of a recruitment index, beach seine experiments were conducted at a large embayment (Mangles Bay south of Perth) and an exposed coastal site (Pinnaroo Point north of Perth) to determine the effects of spatial, temporal and environmental factors on the abundance of these species. Preliminary results indicate the abundance of each species has responded to a unique set of factors. For example, both mullet and whiting species were significantly more abundant at Mangles Bay than Pinnaroo Point. Australian herring abundance was greater during a northeast wind than other wind directions and was the only species that was significantly more abundant during night rather than the day sampling. Additionally, depletion of yellow eye mullet, King George whiting and yellow fin whiting abundance over time (as catch per seine haul) was evident only at Mangles Bay. These results will assist with the future design of a recruitment index sampling program and explain the variation in catches of these species.