Archive for the ‘Uncategorized’ Category

Simple Rules When Interacting with Marine Mammals this Summer

December 7, 2016

Whilst not directly shark related, we felt it important to pass on these simple rules published by Department of Conservation.

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While you are out on the water this summer, if you do encounter a white shark, we would love to hear about your encounter and see any images you may have taken so we can attempt to ID the animal from the growing New Zealand ID database.

Contact us at whitesharkconservationtrust@gmail.com

Stay Safe on the Water this Summer!

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NEW ZEALAND WHITE SHARK RESEARCH

December 24, 2015

White shark research has been conducted arguably since the last 1960’s, but in New Zealand it has only been ongoing for the last 10 years.  Initial studies commenced at the Chatham Islands in 2005.  GmapChatsAt that time white sharks were known to frequent the Chatham Islands and it was considered a potential  ‘aggregation’ site. However popular opinion was that white shark sightings elsewhere in New Zealand were individuals that had strayed off course from Australia and there was no ‘resident populations’.

The research project that initially kicked things off was a joint venture between the National Institute of Water and Atmospheric Research (NIWA) and the Department of Conservation (DoC), headed up by Dr Malcolm Francis (NIWA) and Clinton Duffy (DoC).  The reason for the interest in white sharks in New Zealand was driven by ongoing international concern about their conservation status, particularly their listing on Appendix 1 and 2 of the Convention on Migratory Species, and the almost complete lack of any robust information on the species in New Zealand waters. Knowledge of their low reproductive and growth rates also suggested that reported levels of fishing mortality could be causing their population to decline.  Little is known about the habitat requirements of white sharks, their seasonal behaviour patterns, or their interactions with fisheries.   It was felt that an improved understanding of where they are at what times, and their migratory patterns would allow strategies for reducing bycatch to be developed.  The initial objectives of the project were:

  1. Describe the movements and habitats of these sharks in New Zealand and the SW Pacific.
  2. Identify areas of overlap with fisheries inside and outside New Zealand’s EEZ
  3. Investigate the use of photo-ID as a fishery independent method of monitoring population trends.

The Chatham Islands posed a number of obstacles the scientists had to contend with, rough weather and their remote location being the biggest issues.

Chatham Islands

Chatham Islands

Four pop-off archival satellite tags provided by Dr Ramon Bonfil and the Wildlife Conservation Society, NY, were deployed at the Star Keys in 2005 and numerous other large white sharks were observed.   Those early tags quickly opened new insight into migratory movements of New Zealand white sharks, most notably that the sharks tagged at the Chathams were not migrating between South Australia and New Zealand as expected.   All of the tagged sharks moved north of New Zealand to the Louisville Ridge and New Caledonia.  Based upon the success of that expedition it was possible to secure funding for further satellite tagging and eventually expand the programme to other parts of New Zealand, notably Stewart Island.

Research commenced at Stewart Island in 2007 and has been ongoing there ever since.  Initially, the programme focussed on satellite tagging but was expanded to include photo-identification of individual white sharks using their markings, and acoustic tagging to study fine scale movements. Among other things, it is hoped that the photo-identification project will enable estimation of population size and trend at Stewart Island, removing reliance on traditional tagging methodologies and fisheries by-catch data.  The acoustic tagging study involved the deployment of an array of acoustic receivers around the Titi Islands, Ruapuke Island and Paterson Inlet.

Stewart Island

Stewart Island

Satellite tagging of Stewart Island sharks confirmed they also undertake a seasonal migration to subtropical and tropical regions of the southwest Pacific. Perhaps most importantly the tagging undertaken at the Chatham Islands and Stewart Island has shown that sharks do not appear to move between these locations, although they mix off northern New Zealand and outside New Zealand waters.

Meanwhile,  Clinton Duffy also became interested in the movements of juvenile white sharks which were occasionally reported by commercial and recreational fishermen around the upper North Island, in particular the Manukau and Kaipara harbours.    The first satellite tag deployment was on a 2.1 m TL male in Manukau Harbour in February 2006, and this was eventually followed by another deployments on a 3.2m TL female named Kate off Gisborne in September 2009.   Unfortunately both tags came of the sharks prematurely.  However, both were recovered and provided detailed information on the short-term diving behaviour of both sharks.

In 2011 the first shark was successfully tagged in the Manukau with a SPOT and PAT tag. The 2.4m TL female (Marina) was tracked out of the Manukau and up the west coast to Cape Maria Van Diemen and Cape Reinga where her SPOT tag ceased to transmit (possibly due to the battery going flat).

Clinton Duffy attaches the PAT Tag to Marina's Dorsal Fin

Clinton Duffy attaches the PAT Tag to Marina’s Dorsal Fin

Her PAT tag continued to function and it detached off the East Coast of Australia and was recovered on a beach in southern Queensland.  The tag was returned to Clinton and the information is currently being analysed.  We hoped to hear about her movements in detail this year but unfortunately there has been insufficient time to start analysis.

In the summer of 2012 tagging expeditions continued in the Kaipara with one shark a 1.8m TL male named Scotty successfully PAT tagged and a number of other small white sharks seen.  In January 2013 a 1.5 m TL male was SPOT tagged in Kaipara Harbour but no transmissions were ever received.  The reason for this is unknown.  No sharks were tagged off the North Island in 2014.  From 2010 through to the summer of 2015 a number of white sharks were encountered on each expedition however tagging success was low.  This was attributed to the very low water clarity and the method of capture that was being deployed during this time period.   However the annual expeditions to Stewart Island proved extremely fruitful both in terms of the tagging studies but also the development of the photo ID database, which now includes more than 120 individuals.  The team deployed acoustic tags and set up an acoustic array to further investigate fine scale movements of sharks in the research area.  60 sharks received acoustic tags and the fine scale study revealed some interesting information of their movements.  One such revelation was the fact that the acoustic array set up around a local salmon farm actually got no hits at all.  It was expected that the nets, and any escapees would attract seals and so also attract white sharks.  This was not the case.

The Kiapara expeditions were assisted by IGFA member and expert sport fisherman, Scott Tindale on the Red October.  Scott applied his years of experience with game fishing and developed a new method of catching the sharks which was put into practice in 2015.  In addition to Scotts help with a new rig the expedition took a different approach exploring the Kaipara harbour and tried a different location – less the 5 km from Shelly Beach.  This changes in catch approach and location brought a change in success and on the first day out a total of 8 white sharks were seen, six were actually hooked by us, and three were tagged.   The first to be tagged was a 2.2m TL male (Thomas D).  This shark was tagged with both a SPLASH and a PAT tag. He was quickly followed by a 2.1m TL female (Caitlin) which was tagged with a SPOT tag.

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Catlin’s dorsal fin and SPOT tag

The last,  tagged towards the end of the day, was a 3.4m TL female.  She was tagged with a PAT tag and given the name ‘Sue’.

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Sue with PAT tag

The following day a further three sharks were hooked but no tags were deployed.  Two weeks later another three sharks were hooked with two being successfully tagged – a 2.5m TL female named ‘Lea’ which was tagged with a SPOT and a mini-PAT tag, and a 3.3m TL female named Cindy that was PAT tagged.

There have been no further white sharks successfully tagged this year, however tracking the ones tagged in January provided interesting data.  Catlin was the shark that ‘reported back’ most and she was tracked throughout the year travelling.  Initially she appeared to be heading toward Pandora Bank or possibly Spirits Bay.

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Catlin’s movements along Ninety Mile Beach in 2015. index6

However she returned to the Kaipara in June, travelling from Pandora Bank averaging a travelling speed of 3.24 km p/hr.   Clinton was particularly interested to see if she would stop sending signals once she entered the harbour as it could indicate a change to more bottom-orientated foraging behaviour which snapper also do in turbid water.

 

 

 

 

The 2.5 m female (Lea) tagged on Jan 8th proved to be rather secretive.  The first fix on her tag was received north of the Graveyard off Lake Wairere on Jan 14th followed  by a single fix 4.7 km outside the bar.  Thereafter the were no signals to indicate where she was.  Equally nothing heard from the 3.3 and 3.4 m females that were PAT tagged.  This is not to say the tags were not working as  often a lack of signals can be due to the wet/dry sensor or aerial being fouled, or simply due to the shark spending only very brief periods of time at the surface.  With a lack of regular report backs, recovery of the tag is vital.

‘Cindy’, the 3.3 m TL female  on 8 Feb 2015 released her pop-off tag earlier than expected and started transmitting from over the Tonga Trench about 260 km southeast of Tongatapu, water depth a bit shy of 6000 m in August 2015.  This has allowed for some data to be transferred, however as the tag has not been recovered, there is no detailed report of her movements.

Sue, the 3.4 m female caught in Kaipara River on 17 January however the tag started transmitting from a position 219 km southeast if Isle Hunter (Hunter Island) on Hunter Ridge; 707 km Southeast of New Caledonia and 739 km Southwest of Viti Levu, Fiji.

Finally, the mini-PAT tag on Lea, the 2.5 m female  started transmitting four days later than expected in November. There were no position fixes from the transmissions and the tag then went silent again after three days before Clinton obtained a position fix from this tag in the Tasman Sea 114 km west of the Challenger Plateau (619 km west of Cape Egmont). This shark’s SPOT tag last transmitted close to Pandora Bank, off Cape Maria Van Diemen.  It looks like it may be on its way back to New Zealand from eastern Australia so it was hoped the tag continued to transmit in order to reconstruct its track to confirm that the theory.

We were hoping to assist in deployment of another 6 tags before the end of the year, however weather conditions this spring and summer so far have prevented any opportunity to get back out on the water.

 

 

 

 

 

 

 

 

 

2014 New Zealand Zoological Society Seminar

August 10, 2014

2014 New Zealand Zoological Society SeminarClick here for more information

Permits to be Required for Cage Diving Operations

March 2, 2014

Recent events in Stewart Island have resulted in the Minister of Conservation, Nick Smith, announcing this week that as of the final quarter of 2014, all commercial white shark cage diving operations in New Zealand will require have a permit under the Wildlife Act 1953. The timing of this requirement ties in with the start of the 2014/2015 summer season.

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Until now government has been reluctant to implement permits for cage diving operations as it was believed such regulations would have a negative effect on the industry, however conflicts between Stewart Islanders and cage diving operators has highlighted the need for the growing industry to be properly managed. Commercial paua diving is an important industry on Stewart Island. New Zealand law dictates their work must be done without the aid of compressed air and they must free dive for their bounty. Many are convinced the cage diving operations attract sharks into the area and modify their behaviour.  Their main concern is that the presence of divers in the cages and the use of berley to attract them,  may condition the sharks to think of divers as food.  The cage diving operators argue that this is not the case and point out that local fishing boats actually discharge far more berley than their operations.

In South Africa, white shark cage diving has been in existence for many years with multiple operators.  The question of behavioural modification has understandably also been a topic of discussion there, and although several studies have been on the subject there has actually been little long-term research into this.  Kiwi born shark scientist, Ryan Johnson and Alison Kock published research work in 2006 (South Africa’s White Shark cage-diving industry -is their cause for concern?) conducted in South Africa which looked directly at this issue.  They concluded that, “Conditioning can only arise if white sharks gain significant and predictable food contravene current permit regulations prohibiting intentional feeding of sharks. On rare occasions, indications of positive conditioning have been observed at Mossel Bay (four sharks).  Evidence exists that adherence to permit regulations and infrequent or no feeding of sharks does not promote conditioning, and may in fact cause sharks to temporally ignore chumming vessels rewards.  Thus, conditioning will only arise if operators intentionally and willfully”.   One observation that is made time and time again by cage diving operators (and their customers) worldwide is that in visiting the same dive zones regularly, there is never a guarantee that a white shark will even show up.  It may take a few minutes, or a few hours or none arrive at all.  This fact alone must in some way indicate that ‘conditioning’ to associate cage operators and humans with food is questionable so long as the cage operators do not intentionally feed the sharks or use excessive berley to attract them.

In July 2013 the Department of Conservation published interim guidelines for operators of commercial white shark cage diving operations.  The guidelines were issued to ensure cage dive operators conducted their operation in a manner that ensured the wellbeing of the sharks. The interim guidelines identified some activities associated with cage diving that pose a risk to great white sharks.  Within Appendix B of the guidelines, a table of possible risks in the operation touches on the subject on possible conditioning with respect to throw baits and states only one throw bait should be used at a time and all efforts should be made to not allow the shark to take a throw bait.

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The Department of Conservation had originally intended the interim guidelines to be reviewed and feedback given by operators in 2015, however, the recent visit to Stewart Island by Nick Smith has changed this and permits will now be required by the end of 2014.

References:

Commercial Great White Shark Cage Diving New Zealand.  July 2013.  Department of Conservation Interim Guidelines

South Africa’s White Shark cage-diving industry -is their cause for concern? Johnson, R. and Kock, A. 2006

The effects of shark cage-diving operations on the behaviour and movements of white sharks, Carcharodon carcharias, at the Neptune Islands, South Australia. Bruce, B.D., and Bradford, R.W. ; 2012

Effects of a cage-diving operation on the fine scale movement of white sharks (Carcharodon carcharias).  Huveneers, C. , Rodgers, P.J., Beckmann, C., Semmens, J., Bruce, B.D. and Seuront, L. 2012

For further information about cage diving and possible behavioural conditioning please refer to the above links.

Tragic Incident at Muriwai

February 27, 2013

We are deeply saddened at the news of the shark incident at Muriwai earlier today that took the life of a swimmer. Our deepest condolences go out to the family and friends.
Exact details of the incident remain unclear, but we hope this will change as the investigation continues. From what we know the incident occurred about 200 meters from shore and involved a single shark estimated to be around 12 feet in length, and a long distance swimmer. The shark species remains unidentified at this time. We understand police were quickly on the scene in a launch to recover the swimmer’s body. It is unclear whether the shark is still in the vicinity and the beach will remain closed for a few days while aerial searches are done.
This tragic event is a very rare occurrence in our waters, even though we know sharks to be present all year round.

Raffle: Win a cast shark tooth pendant and support the education programme!

October 7, 2012
Mark Stotesbury made and generously donated to the Trust five cast teeth from South Africa that were left by sub-adult shark in a decoy during research work that was being conducted by Chris Fallows (Apex Predators) and Rob Lawrence (African Shark Eco Charters).

Mark cast this tooth in a spin caster mould in zinc and plated with nickel, brass, gunmetal, antique nickel and antique copper.

No sharks were harmed in gaining this unique pendant opportunity, so we are more than happy to offer you the chance to win one!

Mark Stotesbury’s cast teeth in antique copper, nickel, brass, and gunmetal (clockwise from left)

To enter the draw to win a tooth, simply pick a raffle number between 1 and 100.   There is a limit of 5 numbers per member, and each number you choose costs $5.00.  Email/send us your chosen numbers and the entry fund (you can send us a Paypal receipt, or snail mail is fine – no cash though!), and we will log your choice.  We will announce the winners in the next newsletter.The funds from this raffle will be going towards the education programme fundraiser. We are currently raising funds to help schools send classes to Kelly Tarltons to engage in a one day educational visit.  The schools we are raising funds for do not have the financial resources to be able to send their pupils on such educational visits.  We would like to help children benefit from what we believe to be an extremely worth while and highly beneficial day out.  We hope you will feel as we do that finances should not restrict the learning potential of our kids and help us to reach our goal of $7,500 over the next year. (more…)