Rena spill: ecosystems most at threat, plans for monitoring

Thursday, 13 October 2011, 11:19 am
Press Release: Science Media Centre

Rena spill: ecosystems most at threat, plans for ongoing monitoring
13 October 2011
As an oiled wildlife response team works to save animals caught in the oil spilt from Rena and beach clean-up continues, scientists are looking at the potential impacts of the spill on sensitive coastal areas of the Bay of Plenty.
The University of Waikato's Professor Chris Battershill, a coastal and marine systems experts who holds the Bay of Plenty Regional Council Chair in Coastal Science and is based in Tauranga, is currently on the scene assessing the spill's impact.

The SMC conducted the following Q&A with Professor Battershill. Feel free to use these quotes or contact the SMC for further information.

- What do you think are particularly vulnerable ecosystems south of Tauranga where oil in mudflats or other soft sediments might pose particular problems?

"Maketu and adjacent Waihi estuaries were two systems identified as being particularly vulnerable for the most part due to their cultural significance, food source importance for iwi and local resdients and also because of the high abundance and diversity of estuarine bird life seasonally present.

"These estuaries were found to be vulnerable in the early modelling projections for oil spill trajectory given the predicted at the begining of the incident and sadly those predictions appear to be now realised. Tauranga Harbour itself was also identified as being vulnerable should oil be directed by wind toward Matakana and Mount Maunganui. Although a narrow entrance somewhat shelded by the Mount, the strong currents on the incoming tide is likely to entrain surface slicks into the harbour.

"The landward side of Matakana (and the river like subestuary there) and Waikareo and Te Puna subestuaries were also likely to be in the line of fire Seagrass beds of Otumoeti and Matua were also deemed vulnerable."

- When the spill has been brought under control, what kind of monitoring programme do you think should be put in place to check on the longterm damage to coastal ecosystems?

"The Bay of Plenty is fortunate to have had a relatively long history of previous research and monitoring effort. In a search for relevant publications over the last 10 years, over 50 pages of references were readily assembled. There have been long term monitoring programs from the Bay of Plenty Regional Council and the Port Company, as well as research projects from the Polytechnic and the University of Waikato.

"Information is therefore available on the 'before' condition of many habitats, especially the estuaries and open coastal beaches. What was missing was information on the rocky islets adjacent to the Astrolabe Reef, and Motiti Island. In order to establish a baseline by which impact and recovery from the oil spill could be assessed, it was possible in the calm days immediately following the grounding, to mount a rapid survey.

"This was achieved by the University of Waikato, Bay of Plenty Polytechnic and the Mt Maunganui Dive club (represented by Shane Wasik). Samples of representative shellfish and some fish species were also collected for background data on their condition and this added to collections made by the Tauranga City Council. Therefore, a baseline data set was established by which to guage the level of impact of the spill. Monitoring of a representative set of habitats using a robust survey design will be set in place once the storm has abated and when it is safe to dive.

"The ecological character of the habitats will be quantified. In addition, special attention will be paid to species of interest or of significance, due to their reef or sandy shore ecological dominance/influence or because they are kai moana or targeted recreational/commercial inshore fish and shellfish. The montioring program will also incorporate a sampling program to assess petroleum hydrocarbon content (and other relevant chemistry) of tissues of key species (shellfish and fish) as well as sediments.

"The sampling/survey will be intense in the first weeks/months following ease/cessation of the spill and then, depending on the rates of recovery, modified accordingly to record return to the background levels established before the ship grounding event. The selection of sites will be made to ensure the range of habitats present are covered. They will also overlap with those sites previosuly monitored in the BoPRC 10 year program."

- What sites are there where it could be considered there has been sufficient environmental data previously gathered to benchmark such monitoring?

"The 10 year monitoring sites (estuaries and open beaches) get close to benchmarking the 'impact' monitoring program, but some of these have been lost in recent years due to logistic constraints They do however collectively constitute a rare and valuable long term data set. This is rare. In a review of 10 other marine oil spill events none of them had any long term 'prior' information pertaining to the habitats affected, so it was therefore very difficult to prove recovery in any quantitative sense as information on what was 'normal' was absent."

- How expensive and how necessary would is such monitoring?

"The impact assessment and recovery monitoring is of paramount importance, not only to quantify the environmental damage and ecological cost sustained, but also to permit prediction of the time that ecosystem functioning will be restored and to determine how ecological services may come back 'on line', i.e. restoration of the environmental amenity which includes fisheries, kai moana services, recreational amenity, tourism services etc."

"Such monitoring can be expensive depending on the scale and the period over which it runs (in the millions$ over time if ecological function and elements of fisheries recovery are included). There is opportunity however, to build research and training capacity in the region in the process. Given the paucity of information pertaining to how New Zealand species respond to current petrochemical industry related products, there is also a clear need for new research in the ecotoxicology of pollutants utilising relevant experimental procedures. This will no doubt be a focus of future work for the tertiary education agencies in the region and others."

Rena oil spill Resources:

- Recommendations from Science Advisory Panel following Pacific Adventurer clean up.
- Latest updates from Maritime New Zealand
- Real time satellite location data for the Rena and nearby ships
- Bay of Plenty Regional Council information on the Astrolabe Reef
- Cawthron Institute guidelines for Maritime NZ on oil dispersants
- Northland Regional Council backgrounder on oil pollution
- Backgrounder on past oil spills in Australia

International research
- Community Attachment and Negative Affective States in the Context of the BP Deepwater Horizon Disaster (log into the SMC Resource Library for the full paper)
- Acute health effects of the Tasman Spirit oil spill on residents of Karachi, Pakistan
- FAQ on microbes and oil spills

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