A comprehensive monitoring report into the effects of oil pollution from the grounding of the MV Rena on Astrolabe Reef in 2011 shows few long-lasting impacts on Bay of Plenty maritime habitats.
However the environment has not yet returned to its 'pre-Rena state', the report, released at 11am, says.
The 460 page
report covers the first two years of ongoing survey and research work, details one of the most comprehensive, multi-disciplinary studies ever undertaken in response to a marine pollution incident.
In other findings based on laboratory studies done within the project, the impact of heavy fuel oil and the dispersant Corexit on juvenile finfish such as kingfish and flounder, showed effects at higher exposures.
However as the dispersant was used only briefly on the oil spill at sea, and given the strong offshore wind conditions at the time, there were no environmental effects, University of Waikato Chair in Coastal Science Professor Chris Battershill said.
There is now little evidence of remaining oil or tar balls around the Bay of Plenty's coast, and oil washed up on rocky reefs has largely disappeared.
The report was a snapshot in time, covering surveys conducted over the two years since the Rena grounded. Professor Battershill said the survey work was unique internationally because it had been based on comprehensive information about what the environment was like before the ship struck rock, and the philosophy of the approach was steeped in Matauranga Maori [traditional Maori knowledge].
Additional information would come from five Cultural Impact Assessments undertaken by iwi, a mauri assessment of the Maketu area and a Matauranga study.
A surf zone survey is currently underway to assess the extent of any subtidal accumulation of old oil and sand composites given some re-emergence of tar balls, and the beach and rocky shore surveys are being repeated.
