Powerboat-World.com
 
 
News Home Video Gallery Newsletters Features FishingBoating Photo Gallery Sail-World Australia Australian Cruising
MarineBusiness-World

 

Sail-World.com : Fish know how to avoid the spear

Fish know how to avoid the spear

'A Papua New Guinean spear fisherman loading a rifle-style spear gun at the surface. These spear guns are normally hand carved wooden stocks with rubber slings that fire a thin metal rod that has been hand sharpened.'    ARC Centre of Excellence Coral Reef Studies ©    Click Here to view large photo

Fish are not as dumb as people sometimes think: marine scientists have found that fish that are regularly hunted with spearguns are much more wary and keep their distance from fishers.

In investigating the effects of marine areas closed to fishing by customary laws, an international team of researchers working in the Pacific found that fish exposed to speargun fishing take flight much earlier when a diver approaches compared with those living in protected zones.

To assess the effectiveness of marine protected areas and their effects on fish behaviour, the team decided to measure ‘flight distance’ in a range of coral reef fishes which are popular targets for local fishermen in the study area in Papua New Guinea.

'We were studying the effect of the customary reef closures which many groups in the Pacific use,' explains team member Fraser Januchowski-Hartley of the ARC Centre of Excellence for Coral Reef Studies at James Cook University and the Wildlife Conservation Society.

'In developed countries marine areas closed to fishing are a fairly recent idea – but in the Pacific islands, people have been using them for generations, for traditional reasons.'

One of the issues the team was interested in was whether the existence of a closed area changed the behavior of the fish inside it, compared to the behavior of fish outside the area.

Their study took place at Muluk in Papua New Guinea where the local chiefs close areas of reef to fishing, sometimes for several years at a time, whenever it seems the fish are becoming a bit shy. The study looked at fish traditionally hunted by the local people including snappers, triggerfish, parrotfish and surgeonfish.

To study the fishes’ flight distance, a scuba diver slowly approached the fish and dropped a marker at the point where the diver was when the fish was seen to take flight – and a second marker at the point on the reef where the fish was when it fled. This enabled them to measure the distances at which fish fled from the diver, both inside and outside the protected area.

'Fish which are regularly targeted appeared to have a pretty fair idea of the three metre range of the typical rifle-style speargun used by the local PNG fishers', explains lead author Dr David Feary of University of Technology Sydney (UTS).

'Inside protected areas, the fish tended to move off when the diver closed to within two-three metres of them. However those outside the protected zone, where hunting was common, mostly fled when the diver came within four-five metres of them.'

'Quite simply, the fish in areas that were fished regularly were warier and stayed further away- just far enough that it would be difficult to hit them with the spear gun technology used locally.'

In the most extreme case, fish in unprotected areas had a flight distance 2.6 metres greater than the same species of fish in a protected zone – putting them well outside the range of the spear.

A Papua New Guinean spear fisherman pausing on the bottom while searching for nearby fish. Spear fishers in PNG tend not to use snorkels, as they believe air bubbles will frighten away prey fishes. To increase his chances of success, he will have to approach to within three metres of his targeted fish. -  ARC Centre of?nid=81659 Excellence Coral Reef Studies ©   Click Here to view large photo

However when an area was closed, the fish appeared to recover their confidence, allowing divers to approach much closer – within speargun range when the area was reopened for fishing.

Feary explains 'Sometimes these types of closures are used to create a ‘bank account’ of resources that are saved up for important cultural ceremonies. It seems that by closing the area off, communities may not only build up the amount of fish in the area, but make them easier to catch, which helps meet the goal of having fish for a feast. But this may pose a problem where temporary closures are used for conservation rather than community goals.'

'Our results highlight a previously unconsidered mechanism through which a rapid and large decline in fish biomass may occur when a closed area is reopened to fishing; reduced flight distance resulting from protection may increase some fish species’ susceptibility to spear fishing,' Januchowski-Hartley cautioned.

They argue that while temporary closures have value in conserving fish stocks and helping them to recover, their effect on fish behaviour may have to be factored in when reserves are reopened, if the aim is to preserve fish stocks. This may entail the use of gear-restrictions or short re-openings to avoid a sudden, heavy kill of larger fish which have become accustomed to the relative safety of a closed area.

A successfully speared medium sized Oriental Sweetlips Plectorhinchus orientalis. This is towards the upper end of the size range of fishes typically targeted by Papua New Guinean spear fishers. -  ARC Centre of?nid=81659 Excellence Coral Reef Studies ©   Click Here to view large photo

Their paper, Effects of Customary Marine Closures on Fish Behavior, Spear-Fishing Success, and Underwater Visual Surveys, by David A Feary, Joshua E Cinner, Nicholas AJ Graham and Fraser A Januchowski-Hartley appears in the journal Conservation Biology.

http://www.coralcoe.org.au/




by ARC Centre of Excellence for Coral Reef Studies

  

Click on the FB Like link to post this story to your FB wall

http://www.powerboat-world.com/index.cfm?nid=81659

11:52 PM Wed 23 Mar 2011 GMT






Click here for printer friendly version
Click here to send us feedback or comments about this story.


Power Boat News

An auction is set to be held at Runaway Bay Marina, Gold Coast, on Saturday 22nd November. Telephone bidding is available by contacting, Jo on 0407 213 557, or email, jo@marineauctions.com.au. ... [more]  

Garmin, the global leader in satellite navigation, has announced its next generation of open-array digital radars – the GMR™ 424, 624/626 and 1224/1226 xHD2. Continuing to set the standard for open-array radars, the xHD2 series offers brand new features and capabilities that provide better precision, targeting and performance while transmitting power at four, six and 12 kilowatts respectively. ... [more]  

Garmin Ltd has announced a new line of scanning transducers designed to accommodate any calibre of mariner, from the casual cruiser to the professional angler. Supporting both the newest lines of Garmin echoMAP and GPSMAP chartplotters and multifunction displays (MFD), this full array of thru-hull and transom-mounted transducers are a valuable addition to any vessel. ... [more]  

The Maritime Management Centre and Sailability NSW have announced a partnership to promote lifejacket awareness. The Centre has presented Sailability NSW with 50 new generation lifejackets so their volunteers can act as ambassadors by wearing them and role modelling behaviour to further encourage everyone on the water to wear lifejackets. ... [more]  

Arvor reveals new diesel range by Arvor Boats Australia
Boat building should be both creative and technical and Arvor has always sought to push back its boundaries. This is what inspired its creators in the first place. And this is what leads us to the future. This summer Arvor Boats are delighted to announce the launch of two new models to the hugely popular and ever growing Arvor range – the 690 D and 730 D. ... [more]  

Garmin, the global leader in satellite navigation, has announced the GSD 25, a premium sonar module that offers traditional sonar, 1kW CHIRP, CHIRP DownVü and CHIRP SideVü scanning sonar for a versatile, all-in-one black box. The GSD 25 is the ultimate solution for the boater or angler that requires both scanning capabilities and traditional sonar. ... [more]  

Australian luxury cruiser manufacturer Maritimo has recorded one of its most successful Fort Lauderdale International Boat Shows ever with multiple sales of its M58 and M50 cruising motoryachts. Maritimo Sales and Marketing Manager Greg Haines said the atmosphere and positivity at the recent show was the best it had been in many years. ... [more]  

Ferretti Group has announced the opening of its first Flagship Showroom in Shanghai, located in the prestigious Mandarin Oriental Hotel in Pudong. The new Showroom sits on the bank of Huangpu River, in a beautiful location inside Mandarin Oriental Hotel. ... [more]  

Yamaha Motor Australia announces the end of the legendary V4 Saltwater Series 115C and 130B outboard motors in Australia. These trusted outboards have been powering Australian boaters for almost three decades and are well recognised for their performance and have an enviable reputation for reliability and durability forged in one of the harshest saltwater markets in the world. ... [more]  

Mark Hoult admits that winning a Sirocco tender at this year’s Gold Coast International Marine Expo could not have come at a better time. 'I’m just about to put my 22-foot Steber cruiser on the water for this summer after a year of getting it ready … and I was definitely in the market for a tender,' he said. ... [more]  

The Maritime Management Centre of Transport for NSW is carrying out a review of boat driver licensing in NSW and is seeking your comments. Please also circulate this to your network. The review considers when a licence is required, the classification and duration of licences, the process for obtaining a licence and licence fees ... [more]  

Singapore yacht associations to merge by Don Hoyt Gorman, Superyacht News
Singapore’s two industry yachting and marine associations have agreed to merge and relaunch in time for the Singapore Yacht Show in April 2015, the directors have confirmed. The Singapore Boating Industry Association, which was incorporated in February 2011 as the lead association for Singapore’s recreational boating industry, and the Superyacht Singapore Association, which was formed in 2007 ... [more]  

The 34th Super Boat International (SBI) Key West World Championships produced some of the most exciting racing seen in nearly a decade with the widest range of conditions and excitement. Miss GEICO won the Superboat Unlimited battle and took first overall during some high-flying action on this past Sunday. ... [more]  

Changed boating conditions for power boat races on Lake Albert by Transport Roads and Maritime Services
Boaters are reminded to keep clear of Lake Albert at Wagga Wagga this weekend for the safe staging of power boat races. Roads and Maritime Services has granted an exclusive use aquatic licence to Australian Formula Powerboat Grand to host the event between 7am and 6pm on Saturday and Sunday. ... [more]  

If you love water skiing, this is an event you cannot miss! The brand new Ted Hurley Memorial Classic, a joint initiative of Mildura Ski Club and Ski Racing Victoria is set to kick off in Wentworth on Saturday, 29 November 2014. The race, in honour of Australian water skiing champion and legend Ted Hurley, will take place in two rivers – starting in the Darling River at Wentworth passing though th ... [more]  

Brisbane surgeon Micheal Mastry is a recreational boater who appreciates the very finest in life. Not only does he own a stunning 43’ Nor-Tech Monte Carlo, but the twin Yanmar 8LV powered sports boat is the first in Australia to be fitted with the new Yanmar Joystick Control System. ... [more]  

With attractive marinas and a favourable exchange rate, Malaysia is fast becoming a preferred destination to Singapore for yachting enthusiasts. State Tourism Department director Dr Badrul Hisham Kassim said the yacht tourism which has been privately run thus far, contributed RM529 million to the economy from 2004 to 2014. ... [more]  

Indonesian Govt eases yacht permits to boost ‘marine tourism’ by Nadya Natahadibrata/Grace D. Amian, Jakarta Post
In recognition of the potential of the country’s marine sector to become a key driver of the economy and to create jobs, the new Indonesian government is preparing measures to develop the cruise and yacht tourism industries as part of an effort to double the number of foreign visitors entering the country within five years. ... [more]  

Tahitian ‘Art of Dancing’ & Superyachts by Asia Pacific Superyachts
Superyacht visitors to Tahiti will find there is much to learn and enjoy about the ‘Maohi’ people and the culture of French Polynesia, reports longtime resident Etienne Boutin, heading up Asia Pacific Superyachts Tahiti. ... [more]  

Gamma Yachts has announced the delivery of 22.1m M/Y Libertas, the third in its Gamma 20 ‘mini’ superyacht series to be completed to date. With innovative design by Dutch company Vripack, the yacht has impressive guest space for its length overall as well as excellent fuel efficiency. The owner of M/Y Libertas, is the celebrated opera singer Andrea Bocelli. ... [more]  

From the 10th-12th of October at the Mandurah Boat Show, Boab Boats, with major sponsors Honda Marine and RIB Rescue, conducted the first junior power boat challenge within Australia. This was our first step in developing the challenge into a championship and into eventually a national series. ... [more]  

2014 Goodwill Cup - Celebrations are well underway at Southport Yacht Club after the club’s powerboat division regained the prestigious Goodwill Cup from Royal Queensland Yacht Squadron following an absence of four years. ... [more]  

28 entrants in seven teams were at the ISA National Powerboat Championship at Lough Ree Yacht Club on Saturday 1st November. Teams arrived from 10am and started launching their powerboats and were given a chance to familiarise their teams with the location and conditions, with full briefing by Ciarán Murphy at 12:00, the event commenced at 13:00. ... [more]  

Auckland Airport has chosen an innovative Rayglass ProJet to help protect its flights from the possibility of bird strike. The airport’s Rayglass ProJet, named Kaitiaki Rangi or 'Guardian of the Skies', operates around the edges of the airport’s runways, scaring away the birds, especially swans, that sometimes congregate on the nearby banks ... [more]  

2014 Goodwill Cup - Celebrations are well underway at Southport Yacht Club after the club’s powerboat division regained the prestigious Goodwill Cup from Royal Queensland Yacht Squadron following an absence of four years. ... [more]  

As the RYA Suzuki Dinghy Show / Suzuki Marine competition to win a brand for your club passes the half-way point there is still time for you to get your entry in to be in with a chance of winning. The competition, which runs until 31 January 2015, is proving popular with boaters around the country with thousands having already submitted their entry in the hope of clinching this fantastic prize. ... [more]  

Victorian Premier Denis Napthine today unveiled a $65 million Better Bay Plan and announced that commercial netting in Port Phillip Bay and Corio Bay will be phased out. Dr Napthine said the comprehensive plan focused on preserving and rehabilitating one of the state’s best assets, while also building important community infrastructure to enable more people to enjoy Port Phillip Bay. ... [more]  

This year, the land part of the boat show will be relocated to an artificial islet, Music Island, in Wuyuan Bay. The island was created with construction waste during the reconstruction of Wuyuan Bay, and covers an area of about 63,400 square meters. It has pleasant surroundings, such as a mangrove, black swans and beautiful bridges. ... [more]  

The media conference marks the opening of the 2014 China (Macau) International Yacht Import and Export Fair, which will take place at the Grand Colane Resort from 7-9 November. The three-day fair promises to offer its valuable guests a vibrant experience of luxury lifestyle and oceanic culture. ... [more]  

British luxury Motor Yacht manufacturer, Fairline Boats, has announced plans to introduce eight new models over the next three years, with full details to be unveiled at the London Boat Show in January 2015. The news follows on from Fairline’s recent announcement of a major human investment into its engineering capability. ... [more]  

A pivotal metropolitan marine communications centre has been upgraded in a $200,000 project to help safeguard boaters on Sydney Harbour and surrounding waters. The Speaker of the Australian Parliament and Member for Mackellar Bronwyn Bishop will today open the new-look Marine Rescue Terrey Hills radio base, which has been significantly refurbished to secure its operational capability. ... [more]  

Genoa International Boat Show 2014 ‘in recovery’ by Guy Nowell, Sail-World Asia, Hong Kong
Once upon a time, and not so very long ago, Genoa was very much the numero uno Mediterranean boat show, with 3,000+ boats in the water and practically every manufacturer on the planet anxious to be seen there. The combined effect of the financial crisis 2008-onwards and subsequent financial austerity measures imposed by the Italian government, including swingeing taxes on luxury products ... [more]  

2015 Sanctuary Cove International Boat Show - After a successful 2014, Mulpha Sanctuary Cove is gearing up for its 27th annual Sanctuary Cove International Boat Show, with exhibitor opportunities opening next week (November 6). ... [more]  

Eagle One luxury motoryacht – seeking new owner
Ten crucial actions to save the Great Barrier Reef
Henri Lloyd's famous summer sample sale on now
Fort Lauderdale International Boat Show - Australia among the best
sMRT Inflatable SOS Dan Buoy selected by judges for METS Dame Awards
Superior for all seasons
Arrested development – sediment wreaks havoc with fish larvae
Tauranga Boat Expo - Lancer and Sea Blade attend for the first time
Safer Boating Week: New Auckland Council Navigation come into effect
NMMA loses E15 fuel U.S. Court of Appeals Decision
Explore Australia Expo and Brisbane Tinnie and Tackle Show join forces
METS names DAME Award nominees
Barcelona International Boat Show reflects signs of recovery in sector
Still time to win an Advanced Powerboat Course with RYA Handbook
New improved swell forecasting and more locations from PredictWind
A Sailor's Dream Home: View after the Coastal Classic - Auction 22 Nov
Brisbane Tinnie and Tackle Show moving to Manly Harbour in 2015
Partnership to encourage lifejacket use
2014 Gold Coast International Marine Expo: Another outstanding success
Southport’s seas are safer with new Mercury FourStroke Verados
2014 Gold Coast International Marine Expo - Marine Syndication wins   
UIM Class 1 Grand Prix of Italy - Wins for Fendi Racing and Aquasport   
Coast Guard rescues two near Wachapreague   
Scotland’s Boat Show - More than 13,000 flock to Kip Marina   
Grand Prix of Italy: Victory and Bernico-New Star claim race 1 honours   
2014 Gold Coast Int'l Marine Expo - McDonald’s boosts the family fun   
Yacht CN 2014 —3rd Nansha Bay International Boat Show open   
Dutch boy on a mission to rid the world's oceans of floating plastic *Feature   
Discover Boating Week starts tomorrow   
Great start to another massive Gold Coast International Marine Expo   
2014 Fort Lauderdale International Boat Show - About to start   
Changed boating conditions on Sydney Harbour for Australian Boat Race   
Safer Boating Week puts spotlight on boaties’ behaviour   
2014 Gold Coast Int'l Marine Expo - One more sleep until massive event   
King of Offshore - The Untold Story of Reggie Fountain + Video   
Italian Grand Prix - Teams head for title decider in Terracina   
Boats recovery after Sydney storm   
Partnership to encourage lifejacket use   
Most boaters start the new boating season safely   
Barcelona Int'l Boat Show - 120+ new products and a hundred activities   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png   http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW PBW
LocalAds   DE  ES  FR  IT