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

12:52 AM Thu 24 Mar 2011 GMT






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


Power Boat News

2014 Auckland on the Water Boatshow - Increased visitor numbers show strong support for New Zealand’s leading boat show. Feedback for the 16th Auckland On Water Boat Show (AOWBS), which ran from Thursday 25 to Sunday 28 September 2014, has been overwhelmingly positive, with several significant sales made at the show. ... [more]  

Get set for the Sportjet *Feature by Sirocco Marine
The new Williams Sportjet range is an exhilarating new chapter for Williams Performance Tenders. ... [more]  

Minister for Natural Resources, Lands and Water, Kevin Humphries and Minister for Roads and Freight Duncan Gay have announced the successful tender for the dredging of Swansea Channel has been awarded to Neumann Dredging Pty Ltd. ... [more]  

Have trailer, will travel *Feature by Jeni Bone
All Marine Spares were out in force at last weekend’s Upper Hawkesbury Power Boat Club Spectacular, which drew local and interstate participants and enthusiastic crowds numbering in the several thousand. ... [more]  

Auckland On The Water Boat Show: Images from the final day by Richard Gladwell, Sail-World.com/nz
The Auckland International Boat Show concluded today having enjoyed four days of moderately acceptable weather. Attendance figures have not yet been announced however they are expected to be close to or exceed last year's Show. ... [more]  

Mr Priddy hopes to shave up to seven days off the current powerboat record of 60 days 23 hours 49 minutes, held by New Zealander Pete Bethune. He will make the formal announcement at the Fathom Ship Efficiency Conference in London on Wednesday October 1st. The boat has been designed by Professor Bob Cripps, former Technical Director of VT Halmatic. ... [more]  

A new provisional World Record was set on the Viaduct Harbour today with 52 paddlers covering the 100 metre course on the Lancer SUP. There were no incidents in the attempt - which sets a new mark category in the Guinness World Records. ... [more]  

Marine Rescue Forster-Tuncurry has been named a winner in the 2014 NSW Water Safety Awards, taking out the prize for the Water Safety Event of the Year. The Award, presented tonight, is for the unit’s successful Water Expo, staged in January at the peak of the summer holiday and boating season. The award was accepted by Deputy Unit Commander Ray Mazurek. ... [more]  

Marine Rescue NSW volunteers have been recognised for their enormous contribution to safety on the water, with the rescue service taking out a prestigious title at the 2014 NSW Water Safety Awards. MRNSW won the Most Outstanding Contribution to Water Safety by an Organisation category at the annual awards, presented tonight. ... [more]  

An attempt will be made on Saturday afternoon set set a new Guinness World Record mark for the most people on a Stand Up Paddleboard (SUP) The SUP used for the record attempt will be supplied by leading New Zealand inflatable manufacturer, Lancer Industries, and the SUP uses Lancer's AirDock technology.. ... [more]  

Rescue vessel Point Danger 30 from Marine Rescue Point Danger base, went to the aid of a yacht with mechanical and sail failure shortly before 10 o’clock this morning. The yacht, with three people on board had been experiencing strong winds east of Cook Island off the coast of Northern NSW and was forced to seek help when its engine failed and mainsail blew out. ... [more]  

Having grown into the world’s largest marine motorsport brand over the last 12 years, Powerboat P1 has announced plans to take its SuperStock powerboat and AquaX jet ski race series to Singapore next year as a first step to racing throughout the region. ... [more]  

Sail-World did a quick tour of the on the water exhibits at the Auckland On The Water Boat Show. Her's a quick selection of some of the almost 200 boats on the water in the Viaduct Harbour. ... [more]  

The Auckland On The Water Boat Show opened this morning in brilliant Spring sunshine. Based on the Viaduct Harbour, Auckland, there are nearly 200 exhibiting companies and over 200 boats are at the event which runs through to Sunday September 28. ... [more]  

RBT only applies when vessel is underway by Boating Industry Association
Following some reports RBT testing was occurring whilst at anchor, Michael Drake Principal Manager Boating Safety, Maritime Management Centre, Transport for NSW, has confirmed with RMS legal team that 'RBT only applies when a vessel is underway (i.e. not at anchor, moored or berthed at a wharf or marina)'. ... [more]  

BIA and MIMRA at RMS Boating Safety Day! by Boating Industry Association
BIA and MIMRA will be promoting our 50 Point Safety Check on Sunday the 28th of September, Bayview Boat Ramp, Rowland Reserve, Pittwater Road, Bayview from 10:00 am running until 2:00 pm. ... [more]  

Iridium have recently released the Iridium GO!, their latest product in the satellite communication market. It’s portable, battery powered, and creates a WiFi hotspot. www.predictwind.com!PredictWind!new have partnered with Iridium to put together a package catering specifically to the marine market. ... [more]  

The flagship of Riviera’s award-winning Sport Yacht collection is supremely comfortable with innovative alfresco lifestyle concepts, ultramodern marine technology and palatial appointments – a high-performance yacht akin to a floating six-star resort. ... [more]  

Growing affection for high-end luxury power boats boasting a noble and nostalgic design has inspired the new 54 Daybridge from award-winning boat-builder Belize Motoryachts. ... [more]  

These are some life’s great pleasures and ones you really do want to share. After all, if something has been finely crafted, it’s almost one’s duty to indulge others in the pleasures you’re partaking. Now ever since Aranui's significant keel was first laid down, this 40 footer has been a talking point and it was not long before Corsair Boats were on to building another Bass Straight Motor Yacht ... [more]  

Bristling with innovation, technology and time-honoured craftsmanship, Riviera’s new 515 SUV and 50 Enclosed Flybridge will make their West Australian premieres at the 2014 Mandurah Boat Show from October 10 to 12. ... [more]  

South Australian marinas and yacht clubs are planning a full day of predominantly free on-water and land based events on Sunday 12th October for people to experience the boating lifestyle first-hand and learn how easy it is to get involved. ... [more]  

Making its debut at the Gold Coast International Marine Expo, the BRIG Navigator 700 is 7-metres of versatility and durability, with room for 11 people in comfort – 12 in the twin engine version. ... [more]  

Marine Auctions at Runaway Bay hosted their first auction to welcome in Spring with a bevy of boats and marina berths up for purchase. ... [more]  

Digital is an important aspect of today's marketing mix and the marine industry has begun to embrace its importance. ... [more]  

Win an Electronic Device of Your Choice to the Value of $750 for Your Best Profit Idea. ... [more]  

John Crawford never dreamed a love of messing about on boats would lead to the creation of an empire. The Queensland boating identity has come a long way since his obsession for all things marine led him to set up a boatyard on the Wynnum Esplanade in 1964. ... [more]  

The operator of a Portsmouth-based barge has today been made to pay almost £111,000 in fines and costs after pleading guilty to a breach of maritime legislation. Serco Ltd admitted an offence at Portsmouth Crown Court in relation to the health and safety of workers aboard the barge 1706, which is operated as part of a service contract with the Ministry of Defence. ... [more]  

You scratched my seagrass! by Steven Katona, Newport, RI
Sailors for the Sea publishes monthly articles that translate the language of marine science into fascinating articles about ocean health. ... [more]  

Join us on Boating Safety Day on 28 September by Roads and Maritime Services
Boating Safety Day is a free community event for the whole family. Join us across NSW on Sunday 28 September, between 10am and 2pm, enjoy a range of marine activities and learn about safe and responsible boating. ... [more]  

The closed waters area between Indian Head and Waddy Point at Fraser Island will re-open to the taking of finfish from midday Tuesday 30 September. Queensland Boating and Fisheries Patrol (QBFP) district officer Geoff Fergusson said the closure was in place to protect finfish during their breeding cycle. ... [more]  

Lancer Industries Ltd returns to the Auckland On Water Boat Show after almost a decade away. It will mark several significant events for Lancer including new pricing, a Guinness World Record attempt and an Introduction to Sea Blade. The Lancer stand is located beside the ETNZ building. ... [more]  

Dangerous conditions forecast for NSW boaters by Roads and Maritime Services
Roads and Maritime Services has issued an alert after a Bureau of Meteorology warning about dangerous surf conditions from Gabo Island to Tweed Heads developing tomorrow, Sunday 21 September. ... [more]  

Genoa International Boat Show 2014 responding to a changing market
New Zealand boating industry showing strong growth
Ten safe and clean refueling tips for boaters
Mercury heads field in ski racing’s World Championship selection
Abbot Point onshore disposal
New Zealand's largest on water boat show kicks off next Thursday
Auckland Water Boatshow: Practice session for Guinness World Record
Brisbane to host new boat show at Manly on Moreton Bay *Feature
2014 Honda RYA Youth RIB Champions crowned + video
Great Barrier Reef plan released for comment
Superior prepares for Monaco Yacht Show debut *Feature
Sharks more abundant on healthy coral reefs
RYA Advanced Powerboat Handbook unveiled at PSP Southampton Boat Show
Brisbane Boat Show - Opens with great attractions and innovations
Brisbane Boat Show begins *Feature
P&O and Princess Cruise Ships to continue operating into Abell Point
No more XCAT action in China this year, but landmark agreement signed
Yamaha major sponsor of 2014 Rip ‘n Ride 7
Superboat Champ: Maritimo well positioned as race series nears its end
Command Thrust outboards with Counter-Rotation find eager market
Southport Yacht Club celebrates opening of 68th season *Feature   
Brisbane Boat Show starts Friday - biggest in 10 years! *Feature   
Marine Auctions adds new recruits   
Ministerial advisory group launched by united marine industry sector   
2014 Auckland on Water Boat Show: Coming up at the end of September   
Australian research sheds light on ocean garbage gyres *Feature   
Round the World racer joins Southern Pacific Inflatables   
2014 Gold Coast Int'l Marine Expo - Quintrex factory opens its doors   
Mediterranean Grand Prix - Pons and Chris win the titles   
18 anti-piracy weapons for ships to fight pirates   
Skysol Frame Large: A new shading solution for sunroofs   
Mediterranean Grand Prix 2014 - Wins for Victory and Chaudron   
Mediterranean Grand Prix, UIM-ABP Tour: Pons claims Runabout GP1 win   
Mediterranean Grand Prix - Al Zaffain and Bin Hendi win race 1   
Court judgement a stark reminder about towing safety   
Australian Offshore Superboat 2014 - Superboats ready for Redcliffe   
Southport Yacht Club’s annual Sail Past and Blessing of Fleet Ceremony   
Gosport Grand Prix of the Sea finale to decide P1 champions   
Camper & Nicholsons Yachts presents the Sagitta 42   
GT15 and GT30 European Championships - Jelf takes to the podium twice   


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 VIR PBW
LocalAds   DE  ES  FR  IT