Fisheries research report No. 181 - Developing long-term indicators for the sub-tidal embayment communities of Cockburn Sound

Authors

Danielle Johnston, Department of Primary Industries and Regional Development, Western AustraliaFollow
C. Wakefield, Department of Primary Industries and Regional Development, Western AustraliaFollow
A Sampey, Western Australian Museum
J Fromont, Western Australian Museum
D C. Harris, Department of Fisheries

Publication Date

10-2008

Series Number

181

Publisher

Department of Fisheries

City

Perth, Western Australia

ISBN

1 921258 33 0

ISSN

1035 - 4549

Abstract

Swan Catchment Council Project – 01-0506 T 2006 – 2008 program

The geomorphology of Cockburn Sound is unique to the lower west coast of Australia due to the relative paucity of sheltered nearshore marine embayments along this coastline. Numerous studies on many of the commercially and/or recreationally important species that inhabit Cockburn Sound have demonstrated that for many of them this marine embayment constitutes an integral part of their life history. Since the commencement of industrial and urban development in the mid 1950s, in the waters and along the shores of Cockburn Sound, the marine fauna utilising this area have been exposed to ongoing changes in environmental quality. These detrimental, anthropogenic influences have impacted on many attributes that affect the faunal composition, including, for example, habitat alteration and/or loss.

Recent data has also revealed that blue swimmer crab stocks in Cockburn Sound are more vulnerable than previously thought with this fishery collapsing in 2005/06. The broader impacts of the declining numbers of crabs on the ecology, i.e. predator-prey relationships, are unknown. Likewise, adult populations of snapper in the lower west coast region have been identified as being low/depleted. Recent studies on the biology of snapper have identified the nearshore marine embayments of Owen Anchorage, Cockburn and Warnbro Sounds as important sources of recruitment for the adult population. Until recently, very little research had been done on the structure of the faunal community in these embayments to which blue swimmer crab, snapper and other commercially and/or recreationally important species belong. A broader understanding of the diversity of fauna that resides in this marine embayment will provide insights into their ecological interactions and thus aid in their sustainable management.

The objectives of this study were:

1. Describe the trawled community structure associated with the key indicator species, i.e. blue swimmer crabs and snapper, in Cockburn Sound.

2. Assess changes in the distribution and abundance of blue swimmer crab and snapper by comparison with the Department of Fisheries long-term dataset.

3. Establish a system to monitor the abundance and distribution of sub-tidal embayment faunal communities in Cockburn Sound.

Number of Pages

114

Keywords

Department of Primary Industries and Regional Development, Biodiversity, Cockburn Sound, trawling, indicator species, blue swimmer crabs, snapper, marine embayment

Disciplines

Aquaculture and Fisheries | Biodiversity | Marine Biology | Natural Resources and Conservation | Natural Resources Management and Policy | Sustainability

Recommended Citation

Johnston, D. J., Wakefield, C. B., Sampey, A., Fromont, J. & Harris, D. C. 2008. Developing long-term indicators for the sub-tidal embayment communities of Cockburn Sound. Swan Catchment Council Project, 01-0506 T. Fisheries Research Report No. 181, Department of Fisheries, Western Australia, 113p.