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Wherowhero, Gisborne, March 2013

The Wherowhero Lagoon is an area of amazing diversity including a number of threatened or at risk species. An oil spill exercise in March revealed some very useful information about the local habitat, which will increase the relevance of the Regional Oil Spill Contingency plan.

On the 19th March 2013, an oil spill exercise was conducted at Wherowhero Lagoon, near Murawai in Gisborne. The exercise was run by the Gisborne Regional Council and led by members of the National Oiled Wildlife Response Team (NOWRT).


NOWRT-exercise---Wherowhero_jpg.jpeg The location

The Wherowhero Lagoon hosts a diverse array of wild bird species, including threatened northern New Zealand dotterels and many shorebird species forage extensively on the exposed mudflats as the tide recedes.  The Orongo wetland is a significant conservation initiative in the region, which lies south of the lagoon.


The scenario

An oil spill occurs at sea, in the vicinity of the lagoon entrance.


The process

An operations base was set up at Murawai Beach and a field team was dispatched to survey the region. Key tasks for the field team included identifying species at risk from oil contamination and identifying priority areas for protection.

A wildlife survey of the lagoon was conducted on foot and by vehicle by Gisborne NOWRT Reps Sandy Bull and Darryl Coulter, and Helen McConnell from Wildbase, Massey University.



Over 400 birds comprising 20 species were identified, including eight species classified as ‘threatened’ or ‘at risk’. These included NZ dotterel, caspian tern, pied stilt, pied shag and variable oyster catcher. Many of these threatened species were observed utilising the lagoon entrance and the eastern arm in high numbers. Additionally, northern New Zealand dotterel are known to breed on the end of the sandy spit of the eastern arm. In comparison, on the day of the exercise the northern part of the lagoon was utilised by fewer species, none of which were of ‘threatened’ or ‘at risk’ status. 

The Orongo wetland is connected to the lagoon by a drainage system that allows regular flooding of the wetland. Therefore, it was considered that an oil spill affecting the lagoon could potentially impact these wetlands.

Based on the survey findings, the wildlife response team concluded that priority areas for protection were the eastern arm of the lagoon and the Orongo wetlands. These results will become part of the Regional Oil Spill Contingency Plan.