Case study: Brydes whale voluntary protocol for shipping in the Hauraki Gulf

The Hauraki Gulf is home to a small population of Bryde’s whales, estimated at less than 200 individuals, and is one of only a few places in the world that can boast of a semi-resident population of a critically endangered whale species. The shipping passage through the Gulf is one of the busiest in New Zealand, used by over 1,500 ships per year berthing at the Port of Auckland, the country’s premier cruise destination and primary port. On average, two Bryde’s whales are killed every year as a result of vessel strike within the area, threatening the populations’ long term survival. 2891

Scientific research undertaken by the University of Auckland found that Bryde’s whales spend 90 per cent of their time within 12 metres of the surface, which is the very part of the water column which ships hulls penetrate, with most large ships drawing between 10 and 12 metres.

The problem of vessels hitting whales also occurs overseas. Vessel strike on the Northern Atlantic Right Whale off the eastern seaboard of the USA and Canada was successfully reduced through the establishment of traffic separation schemes, vessel avoidance areas and speed restrictions. 2892  Scientists investigated the utility of applying these approaches in the Hauraki Gulf. Because Bryde’s whales are distributed throughout the Gulf, with no apparent regular seasonal changes in distribution, a traffic separation scheme was found unlikely to work. The most effective means of reducing the risk to whales was identified as being reducing the speed of vessels transiting the Gulf to 10 knots or less.

A collaborative process involving the Ports of Auckland, the shipping industry, the Department of Conservation, the University of Auckland, the Environmental Defence Society, council representatives and others was commenced in March 2012 to find ways to address the issue. The process was successful, just 18 months later, in developing a voluntary protocol aimed at reducing the number and impact of collisions between Bryde’s whales and large vessels in the Hauraki Gulf.

Pre-planning and speed reduction are the critical factors for preventing Bryde’s whale mortalities. The protocol, which was announced on 20 September 2013, comprises three primary approaches to reducing ship strike: 2893

  • Passage planning - Vessels are encouraged to use recommended shipping routes to enter and depart the port. Narrowing the area of the Gulf transited by ships reduces the risk of encountering a whale. By travelling at a maximum speed of 10 knots whilst in the Gulf, risks associated with an accidental impact are significantly reduced. There is good scientific evidence to suggest that if a whale is hit when the vessel is travelling at 20 knots, the chance of survival is less than 10 per cent, whereas if the vessel slows down to 10 knots, the chances of a whale surviving an impact rises to 75 per cent.
  • Keep watch - When entering or leaving the gulf, especially during daylight hours, vessels are asked to have a dedicated observer equipped with binoculars. If a whale is sighted, vessels are asked to alter course and keep a 1000m clearance.
  • Reporting - In the event of a sighting, the vessels should call in the sighting to Ports of Auckland using a pre-prepared script. Harbour control will then broadcast the message, with coordinates, to all vessels in the area so that they may alter course accordingly. The sighting information is also used for further statistical analysis. 

The voluntary protocol has been notified to all shipping companies, and pilots boarding incoming ships to Auckland ensure that crew are aware of the protocol. A baseline assessment of the speed of ships transiting the Gulf, based on automatic tracking information which is electronically sent by ships via satellite, was undertaken in early 2013. This indicated that the additional time taken to transit the Gulf at 10 knots or less would, for most vessels, be less than one hour. The assessment is being repeated a year later to determine if speeds are reducing as a result of the protocol.

On-going work to promote continued uptake of the new measures are continuing. 2894  Notification of the voluntary protocol to the International Maritime Organization is being considered. Additional research is also underway to count and map whales and other marine mammals in the Hauraki Gulf to build up a better understanding of their distribution.

  1. Mulcahy K and R Peart (2012) Sustainable Seas: Managing the marine environment. 

  2. Mulcahy K and  R Peart (2012) Sustainable Seas: Managing the marine environment. 


Last updated at 4:28PM on February 9, 2018