Marine Pest Inspection of HMAS Canberra. Inspection 2. March 2010

Transcription

1 Marine Pest Inspection of HMAS Canberra Inspection 2 March 2010 Interim report March 2010

2 Marine Pest Inspection of HMAS Canberra. Inspection 2, March Report to: Mr Lachlan Jackson Ranger Team Leader Parks Victoria West Port Philip Report and fieldwork: Scott Chidgey and Peter Crockett CEE Consultants Pty Ltd PO Box 201 Richmond VIC 3121 chidgey@cee.com.au

3 Marine Pest Inspection of HMAS Canberra Inspection 2 - March 2010 Marine pest inspections of the exhmas Canberra dive site were scheduled for 4, 5, 6, 12, 18 and 24 months post scuttling. Pest inspections have been scheduled with the aim of detecting any introduced marine pest species which may become established at the exhmas Canberra dive site. This report discusses the findings of the second, 5 month pest inspection on 4 March The results of the previous inspection (10 February 2010) were reported in CEE 2010 Marine Pest Inspection of HMAS Canberra, February 2010 Interim Report. The key purpose of the marine pest inspections is to detect the potential survival and growth of the marine pest species Undaria pinnatifida (Japanese kelp or Wakame) and Sabella spallanzanii (European fan worm) known from Port Phillip and Corio Bay, both which are listed pest species under the National System for the Prevention and Management of Marine Pest Incursions (NIMPIS). The inspection also focused on other NIMPIS listed pest species known from southeast Australia: Asterias amurensis (North Pacific Seastar) Carcinum maenas (European Shore Crab) Musculista senhousia (Asian bag mussel); Varicorbula gibba (European Clam) The green seaweed Codium fragile subsp. fragile (sun: subsp. tomentosoides, Dead man s fingers) The red seaweed Grateloupia turuturu; and Maoriculpus roseus (New Zealand screwshell) MARCH 2010 INSPECTION Scientific divers (marine biologists) inspected outside surfaces on the Canberra. Divers inspected as much of the exterior of the vessel in the time available in four person-dives. The approximate paths followed by divers are shown below. Figure 1. Approximate pest inspection dive paths (Source: Base profiles and plan of Canberra from Parks Victoria)

4 Marine Pest Inspection of HMAS Canberra. Inspection 2, March No marine pests were detected on exterior surfaces of the exhmas Canberra dive site. The fouling community present on the wreck comprised locally occurring species including pioneer algae and invertebrates. Some of these species are cryptogenic (suspected introductions) or are known to be introduced but are not listed as marine pests. The abundance of attached and encrusting marine growth on the exhmas Canberra continues to increase as both the cover of the surfaces increases and the biomass of the organisms increases. There has been a steady increase in the number of attached species on the wreck, as well as the number of mobile benthic invertebrates and fish associated with the wreck, over time. The composition of the community is discussed in the report on the March 2010 Pest Inspection. Significant changes which have occurred since the previous inspection are: Biomass of fouling organisms has visibly increased over the wreck, with the most noticeable increases on the upper sunlit parts of the wreck (due to increases in algal biomass); Sessile invertebrates continue to increase in size and cover though few new species were obvious in this survey; Benthic mobile invertebrates were abundant in some areas, particularly in the upper algae covered areas; The number of fish species associated with the wreck has increased and there is evidence that the wreck is providing some food for passing pelagic species; Some images of the fouling and associated communities on the exhmas Canberra dive site follow. NEXT SURVEY The next pest inspection and first quantitative ecological survey of the wreck are scheduled for April 2010.

5 Marine Pest Inspection of HMAS Canberra. Inspection 2, March