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

 

'Irregular Accounting': Voluntary Suspension Of Fuji Xerox Govt Contracting

This suspension gives the Ministry of Business, Innovation, and Employment time to understand the full implications of the report from FUJIFILM Holdings into irregular accounting practices at FXNZ. More>>

ALSO:

MPI: Cow Disease Detected In NZ For First Time

MPI is responding to the detection of the cattle disease Mycoplasma bovis in a dairy herd in South Canterbury... The disease is commonly found in cattle globally, including in Australia, but it’s the first detection of it in New Zealand. More>>

South Island Flooding: Focus Moves To Recovery

As water recedes throughout flood-impacted areas of the South Island, Minister of Civil Defence Nathan Guy has praised the efforts of those who were involved in the response to the flooding... More>>

ALSO:

Superu Report: Land Regulation Drives Auckland House Prices

Land use regulation is responsible for up to 56 per cent of the cost of an average house in Auckland according to a new research report quantifying the impact of land use regulations, Finance Minister Steven Joyce says. More>>

ALSO:

Fund For PPP Plans: Govt Embraces Targeted Rates To Spur Urban Infrastructure

The government's latest response to the Auckland housing shortage will see central government and private sector firms invest in 'special purpose vehicles' to fund essential roading, water and drains that Auckland Council can't fund without threatening its credit rating. More>>

ALSO: