Hector's and Māui incidents 1921 - 2008
View summary information of recorded Hector's and Māui incidents from 1921 to 2008.

View summary information of recorded Hector's and Māui incidents from 1921 to 2008.

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Incident summary to 19 March 2008 - Hector's dolphin
Cause of death East Coast South Island South Coast South Island West Coast South Island Unknown population TOTAL
Boat strike 1       1
Euthanased       1 1
Human interaction Harpooned 4       4
Other interaction 5   3   8
Possible human interaction 6   3   9
Known entanglement Cray pot 3       3
Recreational set net 12   9   21
Commercial set net 41   2 2 45
Unknown set net 15   6 1 22
Trawl net 15   4   19
Probable entanglement Salmon farm 1       1
Recreational set net         0
Commercial set net         0
Unknown set net 1   4   5
Unknown net 8 1 4   13
Possible entanglement Salmon farm 1       1
Recreational set net 1       1
Commercial set net         0
Unknown set net 16   10   26
Unknown net 16 1 7   24
Trauma – unknown cause 5 1 3   9
Natural 9 2 6   17
Unknown 14 4 6   24
Not determinable 34 4 31   69
Not available 8 2 14 1 25
Not assessed 39 8 19 1 67
TOTAL 255 23 131 6 415

Some summary figures:

Of the Hector's dolphins where a cause of death was able to be assessed (254 of the 415 total animals):

  • 35% were known to have died through entanglement in set nets; Set net entanglement may have been the cause of death for up to an additional 27% of cases where an assessment of the cause of death was made (possible or probable net entanglements)
  • 7% were found to have died through natural causes
  • 7% were known to have died as a result of being caught in a trawl net
  • A definitive cause of death could not be found for 9%
  • Of the total Hector's dolphin mortalities, 17% were too decomposed or were too fragmented for a cause of death to be determined. A further 16% were not assessed for cause of death (mostly historical cases).

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Incident summary to 19 March 2008 - Māui dolphin
Cause of death Total
Human interaction 1
Possible human interaction 1
Known entanglement Unknown set net 2
Probable entanglement Unknown net 1
Possible entanglement Unknown net 2
Natural 3
Unknown 1
Not determinable 7
Not assessed 23
TOTAL 41

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Explanation of cause of death categories

Human interaction
No sign of net entanglement, but definite signs of other types of human interaction e.g. high degree of mutilation.
Possible human interaction
No sign of net entanglement, but indications of other types of human interaction e.g. marks that resemble knife wounds.
Trauma – unknown cause
As read from pathology report – trauma, with an unknown cause (i.e. could be natural or human-induced).
Known entanglement
Animal was known (from incident report) to have been entangled and died.
Probable entanglement
As read from pathology report, or presence of net marks on body and one other definite indication of capture e.g. mutilation.
Possible entanglement
As read from pathology report, or presence of net marks on body and a mention of this in incident report.
Natural
Cause of death deemed to be from natural causes.
Not assessed
Necropsy not completed, carcass not recovered, or no assessment of cause of death undertaken.
Not available
Necropsy or incident report not available at present.
Not determinable
Cause of death not able to be determined due to condition of carcass (decomposition, fragmentation etc).
Unknown
Cause of death unexplained or not definitive (e.g. "open" diagnosis in pathology report).

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