Mapping and distribution of Sabella spallanzanii in Port Phillip Bay

Project number: 1994-164

Project Status:

Completed

Budget expenditure: $66,250.00

Principal Investigator: Greg Parry

Organisation: Agriculture Victoria

Project start/end date: 28 Jun 1995 - 30 Jul 1996

Contact:

FRDC

Objectives

1. Describe habitat requirements of Sabella in the Geelong Arm and map the distribution of the worm Sabella spallanzanii in Port Phillip Bay during 1995

2. Determine whether there have been changes to fish communities in regions of Port Phillip Bay affected by Sabella

3. Identify the significance of S spallanzanii in the diets of fish species in Port Phillip Bay.

4. Describe the distribution, breeding cycles and larval duration of all exotic species found in Port Phillip Bay in their natural habitats, from published sources.

Final report

Author: Greg Parry

Final Report • 1996-07-05 • 3.30 MB

1994-164-DLD.pdf

Summary

This final report for the FRDC funded project "Mapping and distribution of Sabella spallanzanii in Port Phillip Bay" is considered in two sections: The first section contains original data.' collected during this project to satisfy Objectives 1, 2 and 3 and is organised to be suitable for publication in Marine and Freshwater Research. The second section contains the literature review required to satisfy Objective 4 and will be produced as a VFRI Technical report. Details of the methods, results and interpretation of results are presented in each of these sections and are included in this report as Appendices 1 and 2.

Project products

Report • 1996-07-05 • 1.05 MB

1994-164-PDT-1.pdf

Summary

The sabellid polychaete Sabella spallanzanii, a native to the Mediterannean, established in Port Phillip Bay in the late 1980s. Initially it was found only in Corio Bay, but during the past five years it has spread so that it now occurs throughout the western half of Port Phillip Bay. Densities in many parts of the bay remain low but densities are usually higher (up to 13/m²) in deeper water and the worm's distribution extends into shallower depths in calmer regions. Larvae probably require a 'hard' surface (shell fragment, rock, seaweed, mollusc or sea squirt) for initial attachment, but subsequently they may use their own tube as an anchor. The only measurable effect of the spread of S. spallanzanii on fish communities was an increase in the abundance of little rock whiting, which uses the habitat created by the forest of S. spallanzanii tubes. No fish has been found to prey on S. spallanzanii, possibly because their feeding crowns contain particularly high levels of vanadium.

The channelling of particulate food away from native filter-feeders may have considerable long term effects on fish communities. As the density and coverage of S. spallanzanii increases more energy may be channelled into trophic pathways that appear to lead only to bacterial breakdown upon the death of the worms. S. spallanzanii may also significantly affect the growth and survival of other epifauna with which they compete for food and suitable settlement surfaces.

Report • 1996-07-05 • 1.86 MB

1994-164-PDT-2.pdf

Summary

Twenty two exotic species of marine invertebrates have been recorded from Victorian waters. Eighteen of these are reported from Port Phillip Bay and four are known only from other localities in Victoria. Some of the exotic species recorded from Port Phillip Bay are well established and are present in large numbers, some have been recorded only as isolated individuals and the occurrence of others has been reported but not confirmed.

In this report, literature on the exotic species recorded from Victoria is reviewed, with particular attention being given to those species recorded from Port Phillip Bay. Potential impacts of these introduced species on the local marine fauna are discussed.