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 |
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Boat strike | 1 | | | | 1 |
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Euthanased | | | | 1 | 1 |
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Human interaction | Harpooned | 4 | | | | 4 |
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Other interaction | 5 | | 3 | | 8 |
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Possible human interaction | 6 | | 3 | | 9 |
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Known entanglement | Cray pot | 3 | | | | 3 |
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Recreational set net | 12 | | 9 | | 21 |
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Commercial set net | 41 | | 2 | 2 | 45 |
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Unknown set net | 15 | | 6 | 1 | 22 |
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Trawl net | 15 | | 4 | | 19 |
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Probable entanglement | Salmon farm | 1 | | | | 1 |
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Recreational set net | | | | | 0 |
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Commercial set net | | | | | 0 |
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Unknown set net | 1 | | 4 | | 5 |
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Unknown net | 8 | 1 | 4 | | 13 |
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Possible entanglement | Salmon farm | 1 | | | | 1 |
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Recreational set net | 1 | | | | 1 |
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Commercial set net | | | | | 0 |
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Unknown set net | 16 | | 10 | | 26 |
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Unknown net | 16 | 1 | 7 | | 24 |
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Trauma – unknown cause | 5 | 1 | 3 | | 9 |
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Natural | 9 | 2 | 6 | | 17 |
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Unknown | 14 | 4 | 6 | | 24 |
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Not determinable | 34 | 4 | 31 | | 69 |
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Not available | 8 | 2 | 14 | 1 | 25 |
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Not assessed | 39 | 8 | 19 | 1 | 67 |
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TOTAL | 255 | 23 | 131 | 6 | 415 |
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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 |
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Human interaction | 1 |
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Possible human interaction | 1 |
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Known entanglement | Unknown set net | 2 |
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Probable entanglement | Unknown net | 1 |
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Possible entanglement | Unknown net | 2 |
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Natural | 3 |
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Unknown | 1 |
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Not determinable | 7 |
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Not assessed | 23 |
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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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