Introduction

We administer a database containing information from reports received relating to incidents of Hector’s and Māui dolphin. Get a summary of information from database.

Highlights

Reports may be of dolphins:

  • alive stranded on the beach
  • washed up dead on beach
  • found floating dead at sea or 
  • caught during commercial or recreational fishing (bycatch; may be dead or released alive).

Spreadsheet of Hector's and Māui dolphin incidents: 1921 - 31 October 2018 (XLS, 455K) 

The data is displayed as one row per individual. Some events may include multiple individuals, use the 'MarMam observation ID num' to identify individuals involved in the same event. Event information will be the same for each individual in that event.

Note: Haplotypes are portions of DNA that are only passed on by females, so each dolphin has the same haplotype as its mother. Haplotypes are assigned letters of the alphabet. There are 20 haplotypes in Hector's dolphins, and one that is unique to Māui dolphins (G).

Update November 2018: The spreadsheet has been updated to include all Hector's and Māui dolphin incidents that are held in the DOC database, rather than only records since 2008. The earliest record is from 1921. The fields have also been updated to better reflect data stored by DOC. 

Quarterly incident update reports - includes pathology reports

Quarterly updates are posted about Māui and Hector's dolphin incidents in early May, August, November and February each year. Individual updates are current as at the date of publication, results that are pending at that time will be updated as they are received. Incidents are now grouped per year but will still be updated every quarter.

In order to align reporting and maintain the integrity of government fishery observer programmes, data on observed captures will generally be reported here only in the quarterly report after the quarter that the incident occurred in. You can provide constructive feedback to marinemammals@doc.govt.nz.

Where reports come from

The database relies on reports from the public of dead dolphins they have found. It is biased to areas visited frequently by people and so tends to have more reports from areas that have higher visitor numbers. The database also relies on reports from fishing vessels that may have caught dolphins during their fishing activity.

The earliest record in the database is from 1921. Some reports are historical records from museums or universities, but much of the information in the database is from reports investigated by DOC.

Currently, investigation of all Māui and Hector’s dolphin mortality includes:

  • photographing the dolphin as it was found
  • taking samples and measurements
  • necropsy by veterinarians (the animal equivalent of an autopsy or post-mortem) to determine the cause of death and collect additional scientific samples and information.

What the database contains

The database contains a variety of information about each dolphin, including its sex, size, where it was found, any background information about the incident and information collected during the necropsy.

In some cases, dolphins may not have been assessed for a cause of death as the carcass may have been too decomposed to find out how the dolphin died. In some cases, there may be clear evidence for a dolphin’s cause of death (for example, a specific wound), although in others there may be no clear evidence at all.

Ranger measuring dead dolphin calf.
Trainee Ranger Guy Brannigan measures a dead Hectors calf washed ashore at Warrington Beach near Dunedin in December 2012

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