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 Life And ACC Work Of Sir Owen Woodhouse

With the death of Sir Owen Woodhouse, the founding father of the Accident Compensation Scheme, New Zealand has lost one of the titans of its post-war social policy.

In its original incarnation in the early 1970s, ACC had been a globally innovative “no fault” scheme whereby accident victims surrendered their right to sue those responsible – on the understanding that they would receive compensation at a level that, as Woodhouse famously stated, would be sufficient to enable accident victims to fully participate in social life... More>>

 

Parliament Today:

Bad Transnationals: Rio Tinto Wins 2013 Roger Award

It won the 2011 Roger Award and was runner up in 2012, 2009 and 08. One 2013 nomination said simply and in its entirety: “Blackmailing country”... More>>

ALSO:

Select Committees: Tobacco Plain Packaging Hearings

The Stroke Foundation is today backing the Cancer Society and Smokefree Coalition who are making oral submissions to the Health Select Committee in support of proposed legislation to remove of all branding from tobacco products. More>>

ALSO:

Milk: Oravida Asked For Cabinet Help

New evidence released by New Zealand First today reveals Justice Minister Judith Collins used her position to manipulate the Government to help her husband’s company, Oravida, after the Fonterra botulism scare, says New Zealand First Leader Rt Hon Winston Peters. More>>

ALSO:

With Conditions: Ruataniwha Consents Approved In Draft Decision

The Tukituki Catchment Proposal Board of Inquiry has granted 17 resource consents relating to the $265 million Ruataniwha Water Storage Scheme in a draft decision that would open more of the Hawke’s Bay to irrigation. More>>

ALSO:

Fast Lanes, Campervans: Labour 'Making The Holidays Easier For Kiwi Drivers'

The next Labour Government will make the holidays easier and journeys quicker for Kiwi families driving on the roads, says Labour Leader David Cunliffe. More>>

ALSO:

Gordon Campbell: On Royalty And Its Tourism Spin-Offs

Ultimately the Queen’s longevity has been one of her most significant accomplishments. A transition to Prince Charles while the monarchy was in the pits of public esteem in the mid to late 1990s would have been disastrous for the Royal Firm. Far more congenial representatives have now emerged... More>>

ALSO:

Privacy (Again): ACC Demands Excessive Privacy Waivers

Labour: “This is just another example of ACC under National deliberately acting to deny treatment and compensation... Those who did fill in the form have effectively been victims of yet another ACC privacy breach. This time Judith Collins knew it was happening..." More>>

ALSO:

IPCC: Many Pathways To Substantial Emissions Reductions Available

A new report by the Intergovernmental Panel on Climate Change (IPCC) shows that global emissions of greenhouse gases have risen to unprecedented levels despite a growing number of policies to reduce climate change. Emissions grew more quickly between 2000 and 2010 than in each of the three previous decades. More>>

ALSO:

Bowels: Green Light From Labour For Cancer Screening Programme

Labour Leader David Cunliffe has today committed to a national bowel screening programme, starting with extending the current service to the Southern and Waikato districts. More>>

ALSO:

Dotcom Speaks To Mana AGM: Negotiations With The Internet Party To COntinue

The MANA AGM decided unanimously to continue negotiaitions with the Internet Party. Within a month further negotiations, further consultation with MANA branches and a final decision on whether to proceed with a relationship is expected. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news