Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Boaties need to be mindful of dolphins

Friday, January 31, 2014

Boaties need to be mindful of dolphins


Click for big version.

Severe propeller strike wound on a bottlenose dolphin photographed at Great Barrier Island in September 2012. Photo Credit: Sarah Dwyer, Massey University.

Boaties heading out into the Hauraki Gulf over the summer need to take greater care in sharing the water, Massey researchers say, as they uncover the impact of collisions between vessels and marine mammals in the area.

In a new paper published this month in the New Zealand Journal of Marine and Freshwater Research, the impact of a boat propeller injury on a bottlenose dolphin was reported, with dismaying results.

Coastal-Marine Research Group (C-MRG) PhD student Sarah Dwyer was lead researcher for the recently published paper describing severe propeller strike injuries sustained by an immature bottlenose dolphin (Tursiops truncatus).

“In this instance, the bottlenose dolphin sustained injuries that penetrated to the bone. Considering the severity of the wounds, it was surprising that these injuries weren’t immediately fatal,” says Ms Dwyer.

The injured dolphin was identified as a calf when first sighted in May 2010, based on its size and associated swimming position with an adult bottlenose dolphin presumed to be its mother. The pair were always photographed together for the next two and a half years, until the mother was seen without her offspring a number of months after the injured dolphin was last sighted.

Post injury, the young bottlenose dolphin was observed with a very large open wound behind its dorsal fin and two more evenly spaced parallel wounds on the tail that were consistent with propeller strike injuries. Over the next 23 days, the wounds changed significantly, with increased soft tissue deterioration. The last reported sighting, in the shallow bays of Great Barrier Island, was on October 21, 2012.

It is highly unlikely the mother would have abandoned her injured offspring if it was still alive, therefore it is assumed that the injured dolphin did not survive even though a carcass was not recovered.

Bottlenose dolphins are particularly susceptible to human impacts because they are a coastal species, but Director of the Coastal-Marine Research Group Dr Karen Stockin says that the probability of vessels striking marine mammals decreases when speed is reduced.

“When the injured bottlenose dolphin was observed, it was towards the end of winter, when boat traffic is traditionally low. Risks to marine mammals increase as the number of vessels out on the water rises, so we need boaties to be acutely aware that they’re sharing the waters with other marine mammals, and, more importantly, to immediately report any incidents of vessel strike,” Dr Stockin says.

“Part of our research at the Coastal-Marine Research Group involves performing necropsies on dead mammals to ascertain the cause of death. Some die as the result of blunt force trauma where a vessel has hit a dolphin or a whale hard enough to kill it. We also observe dolphins and other marine mammals with wounds or scars from propeller strikes – some of which they can recover from, and others that later die from their injuries.”

The Hauraki Gulf is home to one of the busiest ports and shipping lanes in New Zealand, with a marked increase in traffic during weekends, with sail boats, personal watercraft (including jet-skis) and recreational fishing boats. It’s also shared with a wide range of marine mammals, including a number of different species of dolphins and whales using the waters to feed and nurse their young.

It’s difficult to work out how many marine mammals are killed or injured by vessel collision or propeller strike, mainly due to the lack of reporting when collisions occur as well as difficulties in recovering fatally-struck animals.

Marine mammals in New Zealand are legally protected under the Marine Mammal Protection Act (1978) — anyone who accidentally kills or injures a marine mammal is required to report the incident to a fishery officer or the Department of Conservation within 48 hours.

The Marine Mammal Protection Regulations (1992) covers commercial whale and dolphin watching activities, and incidental recreational interaction. Under these regulations vessels must avoid rapid changes in both speed and direction and not exceed speeds faster than the slowest mammal within a vicinity of 300 metres. Vessels travelling at speeds over 15 knots are more likely to kill a whale or dolphin if they hit it, and can still cause severe damage if travelling over five knots (or no wake speed).

The popular and highly manoeuvrable jet-ski has quieter underwater acoustics than normal boats. This makes them even harder for marine mammals to detect and avoid, as highlighted in a recent 2013 publication by Dr Stockin and C-MRG research associate Dr Emmanuelle Martinez, who reported the case of a common dolphin that died in the Hauraki Gulf as a result of blunt force trauma caused by a jet ski incident.

Recent C-MRG research aligns with previous studies that suggest most of the dolphins hit by vessels are either young calves or juveniles, or mothers with their young.

“There are several reasons why this occurs. Younger animals are slower swimmers, with limited diving capabilities. They spend more time at the surface and in shallower waters. They’re also naturally inquisitive and less cautious about vessels, so they lack awareness of danger until it’s too late,” says Dr Stockin. “We need people in all kinds of vessels – from commercial ships to motorboats, yachts, jet-skis and kayaks – to be considerate of other species sharing the waterways. The problem is far larger than just container ships hitting whales, yet most people seem oblivious to this.”

Sightings of dolphins can be reported to the Department of Conservation on 0800 DOC HOTline (0800 362 468) and there are also online forms on the website: http://www.doc.govt.nz/conservation/native-animals/marine-mammals/marine-mammal-sightings/marine-mammal-sighting-form/

Links to the published papers can be found here: www.cmrg.massey.ac.nz under the Publications tab.

ENDS

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Gordon Campbell:
On The Inadequate Response To Sexual Violence Prevention

On combatting sexual violence, the government has finally begun to undo some of the problems that were of its own making. Early in March, ACC launched the Integrated Services for Sensitive Claims scheme – a package aimed at improving the attitudes of ACC staff towards sexual violence victims, and offering them more substantive support.

Hopefully, this will help to reverse the damage done with the insensitive, punitive ACC policy put in place by the incoming Key government in 2009, which in some parts of New Zealand, saw 90 per cent of sexual violence victims being turned away by ACC. More>>

 
 

PARLIAMENT TODAY:

"To Help Families Get Ahead": April 1 Changes Kick In

Prime Minister John Key says Paid Parental Leave, the parental tax credit, the minimum wage and Superannuation will increase, while average ACC levies will fall, and more people will be helped in to home ownership... More>>

ALSO:

Climate: Ministers Exclude Emissions From ‘Environment Reporting'

The National Party Government has today revealed that the national environmental report topics for this year will, incredibly, exclude New Zealand’s greenhouse gas emissions, the Green Party said today. More>>

ALSO:

No Retrial: Freedom At Last For Teina Pora

The Māori Party is relieved that the Privy Council has cleared the final legal hurdle for Teina Pora who was wrongfully convicted of murder and sent to prison for 22 years. More>>

ALSO:

Germanwings Crash: Privacy Act Supports Aviation Safeguards In New Zealand

Reports that German privacy laws may have contributed to the Germanwings air crash have prompted New Zealand’s Privacy Commissioner to reassure the public that the Privacy Act is no impediment to medical practitioners notifying appropriate authorities to a pilot’s health concerns. More>>

ALSO:

Treaty: Taranaki Iwi Ngāruahine Settles Treaty Claims For $67.5mln

The settlement includes a $13.5 million payment the government made in June 2013, as well as land in the Taranaki region. The settlement also includes four culturally significant sites, the Waipakari Reserve, Te Kohinga Reserve, Te Ngutu o te Manu and Te Poho o Taranaki. More>>

ALSO:

Gordon Campbell: On A Funeral In Asia, The Northland By-Election, And News Priorities

Supposedly, New Zealand’s destiny lies in Asia, and that was one of Foreign Minister Murray McCully’s rationales for his bungled reforms at MFAT. OK. So, if that’s the case why didn’t Prime Minister John Key attend the state funeral on Sunday of Singapore’s founding leader Lee Kuan Yew? More>>

ALSO:

Werewolf Satire: Not Flag-Waving; Flag-Drowning

The panel choosing the flag options has no visual artists at all. Now, I’ve kerned the odd ligature in my time and I know my recto from my French curve so I thought I’d offer a few suggestions before they get past their depth. More>>

ALSO:

IPCA Reports: Significant Problems In Police Custody

In releasing two reports today, the Independent Police Conduct Authority has highlighted a number of significant problems with the way in which Police deal with people who are detained in Police cells. More>>

ALSO:

Inspector-General of Intelligence and Security: Inquiry Into GCSB Pacific Allegations

The complaints follow recent public allegations about GCSB activities. The complaints, and these public allegations, raise wider questions regarding the collection, retention and sharing of communications data. More>>

ALSO:

TPPA Investment Leak: "NZ Surrender To US" On Corporates Suing Governments

Professor Jane Kelsey: ‘As anticipated, the deal gives foreign investors from the TPPA countries special rights, and the power to sue the government in private offshore tribunals for massive damages if new laws, or even court decisions, significantly affected their bottom line’. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news