Shark news - Thousands turn out to protest the WA shark cull

Thousands of people across Australia turned out today to protest the decision of the West Australian government to cull sharks in the seas surrounding Perth. Protest rallies around Australia were scheduled to happen at staggered times across the country so that each state would be protesting at the same time.

Despite the heat of the day, protesters in Melbourne braved the sun to gather on the steps of the State Library of Victoria. Nationwide, an estimated 6,000 protesters gathered at Cottesloe Beach in WA (1) Manly Beach in NSW (2), Glenelg in South Australia (3) and other locations across the country.

In Melbourne protesters gathered at the State Library of Victoria

When Colin Barnett, the premier of WA, launched his policy to catch and kill large sharks he most likely did not expect the enormous national and international backlash his policy would cause. Armed with banners and decked out in all manner of shark related attire, protesters sent a clear message to the Barnett government - stop killing our sharks!

Protesters proudly displayed
homemade banners

Guest speakers at the rally included shark conservation groups such as Fin Free Melbourne, zoology and genetics major Safia Maher, fisherman Rob Embury, and Shark Defence Australia President Jordan Crooka. The message was clear - the cull has no support from the scientific community or the army of surfers, scuba divers and water users who had turned out to protest Barnett's policy.

Fisherman Rob Embury spoke up against the cull

The rally finished with a march from the State Library to Flinders Street Station. It was heartening to see the crowds marching down Swanson Street cheering "Save our Sharks" and "We don't want your bloody bait!" as a message to the Barnett government to find another way to protect beaches. It was a true tour de force of Australians standing up for their wildlife. Onlookers in the city had their smartphones out and were taking pictures of the protest as it made its way to Flinders Street.

That's the way to dress for a ride!

With so many people gathered nationally to protest this policy it feels as though Colin Barnett is the last man standing who supports the cull. It is hard to imagine that he can continue to stand by and keep his hooks in the water when their is such immense pressure from his countrymen to stop the slaughter.

1) http://au.news.yahoo.com/a/21207700/wa-shark-cull-thousands-gather-at-cottesloe-beach-as-catch-and-kill-protests-ramp-up/
2) http://www.smh.com.au/environment/conservation/thousands-protest-wa-shark-cull-at-manly-beach-20140201-31tiy.html
3) http://www.adelaidenow.com.au/news/south-australia/at-glenelg-and-beachside-suburbs-around-australia-thousands-of-people-protest-controversial-western-australia-shark-cull/story-fni6uo1m-1226815605616

Shark News - Weekend rallies set to oppose WA shark cull

Things are certainly hotting up in Australia as people from around the country will be gathering at one of 16 events occurring nationwide this Saturday to protest the shark cull due to happen in WA. There will also be an international additional event happening in New Zealand. The events have been scheduled in every state and will be happening at a specific time in each state so that the nationwide protests all begin together.

This will be the second wave of rallies across Australia to protest the shark cull. The first nationwide protests happened on the 4th January and made the national news. Since then the movement against the cull has gained  momentum with more Australians lending their support to protecting their wildlife. The cause has also received international attention with celebrities such as Ricky Gervais coming on board to send a message to the government of WA. A recent poll run by UMR showed that 80% of Australians oppose the cull.

The decision by the WA government to implement lethal shark preventative measures came after an increase in shark attacks in the state in recent years with 7 fatal shark attacks between 2011 and 2013. The premier of Western Australia - Colin Barnett - announced the decision to set baited drum lines late last year. Since then the proposal has been fiercely protested by the general public. The cull has also been opposed by leading shark scientists as there is very little evidence to indicate that shark culling is an effective measure to increase public safety. Many parties opposed to the cull also argue that the number of people killed by sharks per year pales in comparison to people killed in rip tides, drownings or road traffic accidents. Despite the overwhelming lack of scientific or public support, Mr Barnett is still standing by his decision to continue with the cull until at least the end of April 2014.  

The first shark to fall victim to the baited drum lines was in the south-west of the state last weekend. Whilst the catching and shooting of the animal - a tiger shark (Galeocerdo cuvier) - caused public outrage there was an even more emotive point to the kill. According to news sources, the commercial fisherman hired to carry out the cull had misidentified the shark as a bull shark (Carcharhinus leucas). Given the striking difference between the two species this mistake is inexcusable and throws into question whether the individual should even be carrying out the job.

Tiger sharks and bull sharks are listed as "Near Threatened" in the IUCN Red List whilst white sharks (Carcharodon carcharias) are listed as "Vulnerable". Colin Barnett has appealed to federal law to lift the protection on these sharks so that he may carry out his cull.

Despite Mr Barnetts seemingly immovable stance on the subject, the protest rallies this weekend look set to be well attended and hopefully will send a message which the government will find difficult to ignore.

Shark research - Evidence that human immunoglobin originated in sharks

Researchers at China Agricultural University in Beijing have traced the evolutionary pathway of modern immunoglobin back to sharks.

Immunoglobin D (IgD) is present in all jawed vertebrates, but its existence in acipenseriformes has previously not been proven. The acipenseriformes are fishes with a cartilaginous endoskeleton which are evolutionarily placed between elasmobranchs and teleost fish. The discovery of the IgD encoding gene in the Siberian Sturgeon (Acipenser baerii) bridges the gap in immunoglobin evolution between elasmobranchs and teleosts.  

A gene encoding immunoglobin W (IgW) has been identified in sharks, whilst the IgD encoding gene has been proved to be present in teleost fish. As IgW has previously been believed to be a homolog of IgD, this would indicate that the IgD found in teleost fish and mammals - including humans - can be traced back to the early evolution of sharks. However, without evidence of similar IgD genes in the intermediate phase between elasmobranchs and teleost fish, the evolutionary pathway could not be assured.

The researchers used polymerase chain reaction (PCR) and high throughput sequencing to identify the IgD gene in the acipenseriform fish A. baerii. The researchers found for the first time that the IgD encoding gene was expressed in the Siberian Sturgeon and furthermore that the gene shared features with that of teleost fish.

Immunoglobins (or antibodies) are key components of the vertebrate immune system and being able to trace the lineage of our own immune system back to sharks provides evidence that sharks have been an important evolutionary template for our own species as well as all fish and mammals which express this antibody.

Lin Zhu, Zhenxin Yan, Mengyang Feng, Dezhi Peng, Ying Guo, Xiaoxiang Hu, Liming Ren, Yi Sun. (2014) Identification of sturgeon IgD bridges the evolutionary gap between elasmobranchs and teleosts.  Developmental & Comparative Immunology. 42(2):138 

Shark Research - Small spotted catsharks are smarter than first thought

Researchers at Cranfield University have found that small spotted catsharks (Scyliorhinus canicula) exhibit cognitive ability with rapid learning skills. The experiment, led by Dr. Joel Cranfield, set out to assess the capacity for cognitive ability in sharks.

Cognitive ability is important for animals inhabiting changing environments such as the oceans - it facilitates memory and learning which improves the ability of an animal to catch prey or search for mates. Whilst marine mammals have been shows to possess cognitive ability, less is known about the capacity of sharks for learning and memory.

To assess the cognitive ability of the small spotted catshark, the researchers focused on the electroreception sense of the shark. Electroreception is an important sensory tool for sharks and rays; it allows them to detect natural electric fields such as those which might be given off by prey items. An assessment of the ability of sharks and rays to distinguish between electric stimuli given off by prey and that of an artificial object - such as undersea electric cables - will be valuable when assessing the impact these artificial electric stimuli may have on marine fauna.

The researchers split the sharks into 4 groups - those which would undergo positive reinforcement and would receive a food reward upon showing interest in an electrical stimulus and those which would not. After each group had participated in the experiment, the groups were switched so that the ones who previously received positive reinforcement no longer would and vice versa.

The researchers found that sharks conditioned to receive a food reward upon investigation of the electric stimulus were far more likely to return and bite the probe than those which had not received any reward, demonstrating rapid learning ability of this species. However when examining the ability of the sharks to retain this information as memory, the researchers found that the sharks possessed a memory of 12 hours to 3 weeks. The small spotted catfish inhabits mainly coastal waters which are highly variable and a memory of longer than 3 weeks may not be a survival requirement of this species. Therefore investigation into other, preferably pelagic shark species, may yield different results and potentially a longer memory time.

Kimber, J., Sims, D, Belamy, P. and Gill, A. (2014) Elasmobranch cognitive ability: using electroreceptive foraging behaviour to demonstrate learning, habituation and memory in a benthic shark. Animal Cognition. 17(1): 55-65

Shark Research – Brazil looks for a better way to keep beaches shark safe

Whilst shark attacks are relatively rare, when there is a sharp increase in the number of attacks it will often provoke public outcry. Between 1992 and 2011 there was an abnormally high number of shark attacks in Recife, Brazil – around 55; the increase in attacks was owing to the development of a new port area in the region.

Whilst the Government was eager to take preventative measures against future attacks, they valued the aquatic ecosystems and understood that gill nets and longlines are non-discriminatory measures which kill species other than sharks. The Shark Monitoring Program of Recife (SMP) was set up to find a technique which could reduce shark attacks whilst causing minimal disturbance to the surrounding ecosystem.

Two researchers from Universidade Federal Rural de Pernambuco (UFRPE) looked at ways this could be achieved. They first used baiting techniques to attract sharks and then relocated problem sharks away from the hazardous area. These techniques showed a 97% reduction in the amount of attacks around the site, and reduction in the mortality rates of sharks and bycatch when compared with gillnets.

During the survey the researchers aimed to reduce the mortality rate of the sharks, as well as to reduce the mortality rate of people using the water in this region. The SMP techniques involved catching sharks using circle hooks – as oppose to the traditional J style hooks – as this lowered mortality rates in the sharks. During the relocation process steps were taken to reduce the stress caused to the sharks – such as covering their eyes with a cloth. Finally the capture and relocation of the sharks afforded the researchers the opportunity to tag the sharks. The tags proved that relocation was a suitable technique in this area, as the sharks did not return to the region after being transported.

The reduction in shark mortality rates was most prevalent in tiger sharks – in South Africa 40% of tiger sharks (Galeocerdo cuvier) are released alive, whereas using the techniques employed by SMP, 82% of tiger sharks were released alive. For the remaining shark species (including bull sharks, blacktip sharks, silky sharks etc) mortality averaged about 30% - which is still a fairly high number when we consider that many of these species are considered Near Threatened in the IUCN Red List of Threatened Species.

The notion of relocating sharks as oppose to culling them is something which this study proved can work – at least in this location. However, whilst it is refreshing to see a government attempting to protect their wildlife whilst keeping sharks away from the public, the fact remains that this study still uses hook based fishing gear to attract the sharks. If steps could be taken to reduce the mortality rate of captured sharks even further, then relocation could be a real, ecologically sound solution to removing sharks from certain areas – after all relocation techniques have been used to remove venomous snakes from properties for years and are a very successful strategy in this regard. 

Hazin, F. H. V. and Afonso, A. S. (2013), A green strategy for shark attack mitigation off Recife, Brazil. Animal Conservation. doi: 10.1111/acv.12096

Shark research: attitudes of divers towards encounters with grey nurse sharks

A recent paper published in Aquatic Conservation: Marine & Freshwater Ecosystems has examined the attitude of scuba divers towards the practice of diving with grey nurse sharks (Carcharias taurus). The research, led by Kirin Apps, interviewed divers who had dived with grey nurse sharks at Julian Rocks and Fish Rock in NSW. Using interview techniques, the researchers sought to learn more about the behaviour of scuba divers at these sites.

The main motivations for wanting to approach grey nurse sharks were to get a better view of the shark and to interact with the shark. However, divers were also concerned that their behaviours might scare the sharks or disrupt the natural behaviour of the sharks. A large proportion of the respondents were concerned that environmentalists would disapprove if they were to approach the sharks and most interestingly there was a great deal of concern regarding the opinion of other divers with some respondents thinking the dive community would approve of their approaching a grey nurse shark and others believing this behaviour would draw disapproval from their fellow divers.

Diver interaction with delicate marine structures such as corals, and marine species such as sharks can unintentionally have a negative effect on the conservation of the marine ecosystem. Furthermore, for many people diving with sharks is a unique experience and the desire to “make the most” of the experience can sometimes lead to behaviours which may not be wholly beneficial to the animal such as touching or disturbing the animal.

However, scuba divers do tend to show respect for the underwater environment and to be in favour of conserving the oceans and recent research has suggested that shark dive tourism overall can contribute to the conservation of many shark species as it is a very effective way of making a shark worth more alive than dead. In a world where the price of shark fin has increased the rate of poaching, making live sharks valuable to governments via shark dive tourism could be a realistic way to ensure that many shark species receive government protection. In an ideal world, all forms of shark tourism would be conducted in a responsible manner which attracted divers to the activity whilst ensuring minimum disturbance to the species involved.  

Grey nurse sharks are listed as Vulnerable in the IUCN Red List of threatened species.  A better understanding of the behaviour of divers towards C. taurus will help researchers and policy makers be more aware of the potential threat towards this species from tourism and implement this knowledge accordingly in their efforts to conserve this species.   

Shark research: Older than we first thought: it takes more than “counting the rings” to age a great white.

Despite the overwhelming fame and notoriety of the great white shark (Carcharodon carcharias) in the media, the reality is that there exists relatively little scientific data on this species. A group of researchers, led by Li Ling Hamady at Woods Hole Oceanographic Institution, used radiocarbon analysis to confirm the age of 8 white sharks and found that white sharks in the northwest Atlantic Ocean (NWA) were likely to live up to 70 years.  

The previous method of aging great white sharks – as with most fishes - was to count the number of mineralised layers laid down in specific tissue such as vertebrae; with this method it is assumed that the layers are laid down on an annual basis. However this method can be vulnerable to misinterpretation and collaboration of results gained in this manner by using radiocarbon dating has gained popularity.

The study, which was published in the journal PLOS ONE, increase exponentially the estimated longevity of C. carcharias in NWA. These results not only have implications for a need to reassess the methods by which sharks are aged, but an increased expected longevity in white sharks raises grave conservation issues. Like most sharks, white sharks are slow to reach maturity and have small litters. If NWA white sharks exhibit even greater longevity than we first thought, this could mean that their expected age to reach sexual maturity could also be longer than originally estimated and this would make white sharks even more vulnerable to fishing pressure and population decline. The white shark is listed as Vulnerable in the IUCN Red List of Threatened Species; many countries protect white sharks but a poor media image has left white sharks vulnerable to persecution – such as the recent decision of the Western Australian Government to bait for large sharks.

Obtaining a greater knowledge of the growth rates and longevity of white sharks will be beneficial for ensuring the protection of this species.  

Hamady LL, Natanson LJ, Skomal GB, Thorrold SR (2014) Vertebral Bomb Radiocarbon Suggests Extreme Longevity in White Sharks. PLoS ONE 9(1):

e84006. doi:10.1371/journal.pone.0084006

Shark Research: Magnets could be used to successfully repel bull sharks

A group of researchers led by Craig O'Connell at the University of Massachusetts Dartmouth, have discovered that C8 barium-ferrite (BaFe12O19) permanent magnets might be the key to repelling bull sharks (Carcharhinus leucas) from shark nets.

The research - to be published in the journal Ocean & Coastal Management - measured the responses of C. leucas to bait and barriers where permanent magnets were present. They discovered that bull sharks were less likely to approach bait or to enter areas when magnets were present. These results suggest that if magnets were used along shark nets they might deter C. leucas from approaching the nets.  

Shark nets are used extensively in three regions of the world: Queensland and New South Wales in Australia, and Kwa-Zulu Natal in South Africa. The use of these shark nets is somewhat controversial; whilst they have been put in place to protect beach-goers from large sharks who may stray close to shore and pose a risk to anyone in the water, the shark nets also result in the mortality of thousands of sharks per year. Furthermore, as the nets are non-discriminatory, other marine life such as dolphins and juvenile whales can also fall victim to shark netting. Finding a guaranteed way to repel sharks away from the nets would not only ensure that sharks are protected from the nets but could even lead to the removal of the nets altogether if the sharks could be kept away from the shore.   

The finding that permanent magnets can be used to deter select elasmobranchs is consistent with what we know about the biology of certain sharks; sharks have specialist sensory organs called Ampullae of Lorenzini which they use to detect bioelectric fields and are hypothesised to be capable of detecting the magnetic field of the Earth.

The researchers plan to publish similar papers focusing on the great white (Carcharodon carcharias), giant hammerhead (Sphyrna mokkaran) and the tiger shark (Galeocerdo cuvier). The inclusion of multiple shark species in this long-term study is important as there is a possibility that highly visual sharks such as C. carcharias may not be as sensitive to magnetic fields as C. leucas. 

With the recent decision of the Western Australian Government to implement a cull of all large sharks in response to a spate of fatal attacks in WA, further research into methods to repel sharks and the potential practical applications could not come at a better time.

Shark travel - bull sharks at Beqa Lagoon

A few months ago I finally made it over to Fiji to dive with bull sharks at Beqa Lagoon. I had been wanting to visit Fiji my whole life and since moving to Australia a year previously I had decided that it was time to make a trip to my new neighbour in the South Pacific.

As a scuba diver, any small island in the South Pacific is a huge draw for me. I have always had an image in my head of perfect turquoise seas, white beaches and water so warm you could bathe in it! When I turned to researching what type of diving Fiji has to offer, something exciting was revealed to me - Fiji has sharks and lots of them! It didn't take me long to realise that Beqa Lagoon was the place to go for the shark enthusiast.

I booked in for bull shark diving and a couple of reef dives with Beqa Adventure Divers. I had researched them quite thoroughly online before I committed and I wasn't about to be disappointed! The staff were fantastic and demonstrated really good customer service throughout.

The day long bull shark dive started with a 7am pick up from my hotel. With Beqa Adventure Divers situated only a 5 minute drive from the main road it was a quick trip to the dive centre where we kitted up. On board the boat we were given some tips on safety in the water. I was advised to switch out my high vis neon yellow ProForce fins for a pair of black stock fins as they would be less attractive to inquisitive sharks (...yes, I took a little persuading to surrender my Force fins!) We were also all issued with thick gloves - again to protect vulnerable fingers from the possibility of getting a small nip! I had brought a shortie wetsuit but was surprised to be given a 6mm full length instead and did find myself shivering a little on the dive - for the majority of the shark dive you are a static observer as oppose to constantly swimming so you can be a little more prone to the cold on this dive.

The first dive started with a descent to 30m and at around 20m I looked down and had my first glimpse of the bull sharks. The black tips (Carcharhinus limbatus) and ragged tooth sharks (Carcharias taurus) I dive with in South Africa get pretty big, but I had not anticipated the sheer bulk of the behemoths below me. Struggling against my ears - which were taking their sweet time to equalise against the depth - I descended painstakingly slowly towards the big sharks.

The bull sharks certainly didn't have personal space issues!

What an awesome sight! The setup of the dive meant that we human spectators were sat by a rocky dropoff, whilst the sharks were encouraged (as much as you can encourage a 2m+ predator!) to swim in the open water in front of us. We spent about 10-15 minutes at this level watching the bulls glide around in front of us. They clearly didn't have any qualms about our presence there and obligingly swam right in front of my camera lens. After this we ascended to about 10m where tawny nurse sharks (Nebrius ferrugineus) and reef sharks were being fed. Huge groups of scissor tail sergeants (Abudefduf sexfaciatus) had decided that the option of a scrap of food was well worth risking the mouths of the sharks for and were present of each dive. I also spotted some lined snapper, butterflyfish and a giant trevally (Caranx ignobilis) darting in and out amongst the sharks. The sheer volume and variety of fish in front of us was overwhelming - at one point I felt a whisper of current between my arms and looked down to catch a tawny nurse shark darting through my arms - the shark had such good spacial awareness that it hadn't even touched me as it sped past.

Bombarded by sharks and fish!

After a surface interval, we descended for a second dive - again with the bull sharks but this time we spend the whole dive with these large predators allowing plenty of time for filming and getting that perfect shot! The sharks were offered bony fish heads from a large bin, which they very politely and patiently almost queued up to get! For the second half of the dive the bin was shut and the behaviour of the sharks changed very quickly. With their attention no longer focused on receiving a meal from the bin, they were suddenly swimming very quickly all around us. Being bombarded by small sharks and fish was one thing, but a huge group of bull sharks certainly tested the nerves! Luckily the bulls were good as gold and showed not even a mild interest in any of the divers. It wasn't long before we were making out ascent and were safely back on the boat.

This is a baited shark dive and as such it draws in larger number of sharks than would be expected in a "natural" setting. I have always had a bit of internal conflict regarding baited shark dives - I generally don't approve of practises which alter the "normal" behaviour of the animals - but in light of the huge pressure on shark populations nowadays from finning, shark tourism may be the key to the long term survival of sharks. Making sharks worth more alive than dead with the tourist dollar is a great way to encourage governments to work to protect their wildlife. Plenty of people travel to Beqa Lagoon to dive with their bull sharks and this brings a lot of money in to the area; the simple equation is no sharks = fewer tourists.

Happy faces after surfacing say it all! 

Details

I went: October 2013. November - April is generally the time of year to avoid as the region can be prone to cyclones.
I flew: From Melbourne to Nadi with Virgin Australia (approx AUD$800)
I stayed: Dormitory style accommodation at Uprising Beach Resort. There are plenty of high end options to choose from in the area though!
I dove with: Beqa Adventure Divers

Shark News: Shark finning banned in New Zealand waters!

Yesterday the New Zealand Government announced plans to ban shark finning, ensure the long-term sustainability of their shark populations and promote shark research and community engagement.

The National Plan of Action for Sharks (NPOA-Sharks) was announced by Primary Industries Minister Nathan Guy and Conservation Minister Dr Nick Smith. With this, the New Zealand Government has pledged to eliminate shark finning (where the fins are removed and the carcass is disposed of at sea) in it's fisheries by 1st October 2015 with the exception of the highly migratory blue shark (Prionace glauca) which will come under the act by 1st October 2016. The elimination of finning for all other species will occur in 2 waves, with an initial group of sharks being protected by 1st October 2014, and the remainder gaining protection in 2015.

Seven species of shark are currently protected in New Zealand waters, including the great white (Carcharodon carcharias) and the whale shark (Rhincodon typus). Of the remaining 70+ species which have been reported to have been caught by fisheries in New Zealand, 11 species account for 90% of the total catch. These include the spiny dogfish (Squalus acanthias), mako shark (Isurus oxyrinchus) and the blue shark (P. glauca). Whilst it is currently an offence to remove the fins from a shark and return the live shark to the sea, the new policy will ban the practice of killing the shark, removing the fins and disposing of the carcass at sea - for any shark killed the entire carcass must be landed.

As well as including cultural involvement with the Maori and recognising the importance of sharks in marine ecosystems, the NPOA-Sharks also emphasises the importance of New Zealand being perceived as having sustainably managed shark fisheries among the international community. This indicates that the recent increase in public awareness of the plight of sharks and high profile media attention which sharks have been receiving of late could be having a positive effect on government policy making. In a media release, Dr. Smith commented "“The 45,300 submissions in favour of the proposal to ban finning show New Zealanders’ attitudes to sharks have come a long way since the ‘Jaws’ days. It is now widely recognised that sharks are an important part of the marine ecosystem and that we need to ensure the 113 species of shark in our waters survive."

Whilst some groups have criticized the NPOA-Sharks, stating that October 2015 is a very long deadline, the implementation of this 5 year plan is a positive step from the New Zealand Government towards ensuring the sustainability of their shark populations and sending a message to the international community that finning is not a practice to be tolerated.

Shark News: Sharks on Twitter

The Surf Life Saving WA Twitter feed (@SLSWA) is doing a fantastic job keeping water users up to date with shark sightings along the WA coast. Previously SLSWA used visual aids - such as shark surveillance by helicopters - to inform water goers that large sharks were in the area. Thanks to efforts by the Shark Monitoring Network to tag large sharks along the WA coast, tagged sharks can now be automatically detected when they stray too close to shore and an alert is sent to the SLSWA Twitter feed. The Tweets transmit data regarding the sharks species (if known), time and location of detection.

As of October, the WA Government reported that they had tagged 136 white sharks (Carcharodon carcharias), 171 whaler sharks (Carcharhinus brachyurus) and 19 tiger sharks (Galeocerdo cuvier).　Troy Buswell - the WA Fisheries Minister - stated that alerts could be sent out within 2 minutes of the shark straying too close to a monitor. The speed of these updates will ensure the SLSWA are able to respond faster to large sharks in the area and take action if necessary.

Whilst there has been some criticism that these Tweets may make large sharks vulnerable to hunting - especially in light of the recent decision of the WA Government to destroy large sharks close to beaches - giving water users advanced warning of sharks will hopefully not only reduce encounters between beach goers and sharks but will make people feel safer about entering the water.

Shark Research: New advice for safe handling of elasmobranch bycatch

A recent article, published in the journal Marine Policy aims to suggest better methods for the handling of the bycatch of sharks and rays in purse-seine fisheries. Bycatch - when other marine animals are unintentionally caught alongside the target species - is a common problem of any non-discriminatory fishing method such as trawling and seine fishing. The most famous example of bycatch is the unintentional landing of dolphins by the tuna industry - as dolphins commonly aggregate with schools of yellowfin tuna they are enclosed in the nets along with the target species and can drown from being enclosed in these nets. However, whilst charismatic dolphins caused a great deal of public outcry regarding this fishing practice, other marine creatures such as turtles and sharks are also commonly caught as bycatch of the tuna fishing industry.

The team spent time on board French purse-seine tuna vessels in the Atlantic and Indian Oceans, observing the practices of the crews and also conducted interviews with purse-seine vessels at port to guage the attitude of crew members towards sharks and ray bycatch.

Presently sharks and rays which are caught as bycatch are released back into the sea by the French tropical tuna purse seine fishery. Bycatch may be released using manual handling techniques; naturally, this may result in danger to the crew from bites and stings (rays) as well as blows to the body from larger species such as whale sharks. Manual handling of sharks and rays (elasmobranchs) may also cause harm to the species - elasmobranchs have fragile, cartilaginous skeletons which are prone to dislocation and damage if handled incorrectly. In addition to this they may suffer organ damage when landed owing to the weight of their own bodies which are usually supported by the aquatic environment.

Whilst there is no economic incentive for fisheries personnel to ensure the live release of sharks and rays caught in their nets, the authors suggested that if practices to improve the live release rate of shark and rays species were quick and easy, then crews would be likely to improve their handling methods.

Successful removal of sharks and rays from the catch requires that the bycatch is anticipated and the crew are trained to handle these large animals correctly. The authors insist that good practice for handling sharks and rays should be taught and used by all members of the fishing industry - one of the worlds most dangerous industries. The manual produced by the authors has been distributed to skippers and posters showing good handling practice of elasmobranch bycatch are displayed on vessels. In addition to this, training workshops have helped to improve the knowledge of crews on the bycatch issues.

Whilst most environmentalists would prefer to see the purse-seine industry become illegal practice - owing to the large numbers of fish taken in one go and the bycatch problem - producing good practice measures for handling bycatch and trying to ensure the live release of sharks and rays accidentally caught in purse-seine nets is at least a step in the right direction for the fishing industry.

The original article can be accessed here or here.