Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Public help sought as hammerhead shark does bit for science

People fishing in the Bay of Islands are being asked to keep a look out for a young hammerhead shark, nicknamed Orokawa.


Photo by Scott Tindale

Orokawa is providing scientists with information on his whereabouts after becoming the first electronically tagged hammerhead to provide useful data in New Zealand waters.

The young shark, just 137cm long, was tagged last Sunday near Deep Water Cove in the Bay of Islands by fisherman Scott Tindale.

“We were anchored within casting distance of the rocks and saw a hammerhead swimming towards us on the surface,” Mr Tindale said.

“I cast a bait towards him and he took it straight away. Because he was small we were able to get him in the boat, oxygenate his gills with seawater from a deck hose, and tag and release him within five minutes.”

NIWA shark expert Dr Malcolm Francis has been contracted by the Ministry for Primary Industries to find out more about the biology, behaviour and stock status of hammerhead sharks in a bid to determine whether they are threatened by overfishing.

Dr Francis and Mr Tindale plan to tag a number of hammerheads – recognisable by their bizarre head shape - in the coming year to determine whether they are resident or migratory and what they do.

Little is known about the species, its habitat or abundance in New Zealand and Dr Francis says the young hammerheads are vulnerable to capture by set nets, longlines and trawls.

“They seem to be very sensitive to capture and most of them die before they can be ret
urned to the sea.”

Since being tagged, Orokawa has crossed the outer Bay of Islands and travelled around the north side of the Purerua Peninsula.

“He is moving around a lot but not going far. He makes a lot of inshore/offshore movements, almost reaching the shore at times,” Dr Francis said.

“This is the first time detailed information on hammerhead shark movements has been obtained in New Zealand waters.”

The only other New Zealand tagged hammerhead to provide useful information was a 2m female tagged with a plastic gamefish tag near Cuvier Island in 2011. It was recaptured east of Vava’u, Tonga, almost two and a half years later and more than 2200 km away.

Dr Francis thinks that this indicates that medium to large hammerheads may be highly migratory, though small juveniles are probably resident in New Zealand waters for the first few years of life.
Despite being common in northern New Zealand waters, hammerheads are rarely seen.

Dr Francis is asking fishers to be on the lookout for Orokawa and if they catch him, to release him as soon as possible.

If he is found dead, the tag on his dorsal fin should be removed and returned to Dr Francis at NIWA.

Orokawa was named after Mr Tindale’s boat and means calm seas.

The tag used on Orokawa is called a SPOT tag. It transmits messages to orbiting satellites whenever the dorsal fin, and the tag’s aerial, break the surface of the sea. The satellite estimates the position of the tag and sends that information via the Argos ground station in France, from where Dr Francis can download the data to his office in Wellington.

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Tourism: China Southern Airlines To Fly To Christchurch

China Southern Airlines, in partnership with Christchurch Airport and the South Island tourism industry, has announced today it will begin flying directly between Guangzhou, Mainland China and the South Island. More>>

ALSO:

Dodgy: Truck Shops Come Under Scrutiny

Mobile traders, or truck shops, target poorer communities, particularly in Auckland, with non-compliant contracts, steep prices and often lower-quality goods than can be bought at ordinary shops, a Commerce Commission investigation has found. More>>

ALSO:

Auckland Transport: Government, Council Agree On Funding Approach

The government and Auckland Council have reached a detente over transport funding, establishing a one-year, collaborative timetable for decisions on funding for the city's transport infrastructure growth in the next 30 years after the government refused to fund the $2 billion of short and medium-term plans outlined in Auckland's draft Unitary Plan. More>>

ALSO:

Bullish On China Shock: Slumping Equities, Commodities May Continue, But Not A GFC

The biggest selloff in stock markets in at least four years, slumping commodity prices and a surge in Wall Street's fear gauge don't mean the world economy is heading for another global financial crisis, fund managers say. More>>

ALSO:

Real Estate: Investors Driving Up Auckland Housing Risk - RBNZ

The growing presence of investors in Auckland's property market is increasing the risks, and is likely to both amplify the housing cycle and worsen the potential damage from a downturn both to the financial system and the broader economy, said Reserve Bank deputy governor Grant Spencer. More>>

ALSO:

Annual Record: Overseas Visitors Hit 3 Million Milestone

Visitor arrivals to New Zealand surpassed 3 million for the first time in the July 2015 year, Statistics New Zealand said today. The record-breaking 3,002,982 visitors this year was 7 percent higher than the July 2014 year. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news