Mitigation of vessel-strike mortality of endangered Bryde's whales in the Hauraki Gulf, New Zealand


Constantine, R., Johnson, M., Riekkola, L., Jervis, S., Kozmian-Ledward, L., Dennis, T., Torres, L.G. and N. Aguilar de Soto



Journal/Publisher Name: 

Biological Conservation

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Corresponding author at: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Tel.: +64 9 923 5093. E-mail:

Bryde's whale (Balaenoptera edeni) behavior was studied using suction-cup attached tags. Behavior was studied to identify potential mitigation measures that could reduce lethal vessel strikes in the Hauraki Gulf, New Zealand. Tagged whales spent 91% of their time at depths within the maximum draft of vessels. This behavior could increase the potential for vessel strikes. Analysis of vessel transits and whale sightings suggested that re-routing of vessel traffic in the Gulf would not be beneficial because whales are distributed throughout the Gulf. Passive acoustic devices are not viable due to the low vocal activity of whales and potential masking of noise from vessels. A social forum was developed with stakeholders. The only viable option decided upon by this forum was a Transit Protocol for Shipping which includes voluntary speed restrictions and a monitoring plan.