According to the 2015 Worldwide Shark Attack Summary of the International Shark Attack File (ISAF), 2015 saw a record high number of unprovoked shark attacks. Out of a total of 164 recorded attacks, 98 were categorised as unprovoked; this figure surpasses the previous highest number of 88 unprovoked shark attacks in 2000.
However, before you go grabbing your speargun and practising the line "Smile you son of a bitch", it's important to point out that whilst the number of unprovoked attacks has risen in 2015, the overall rate of attacks could very well have remained unchanged or even fallen. The researchers who curate the ISAF attributed the increase in shark attacks to more humans in the water and better reporting of shark attacks rather than an increase in the rate of shark attacks. The researchers also caution against putting too much faith in short term trends owing to year to year variability of environmental conditions which can affect shark populations.
Of the 98 unprovoked shark attacks in 2015, there were only 6 fatalities worldwide and long term trends indicate that the rate of fatalities owing to shark attacks is decreasing. Whilst news of shark attacks will always draw media attention and excitement, the numbers pale into insignificance when compared to the 1.24 million people who were reported to have been killed in road traffic accidents in 2010.
Geographically the majority of the shark attacks occurred in North American waters, with Australia coming a close second with 18 unprovoked attacks - 1 of which was fatal. People participating in activities which caused a lot of surface turbulence such as surfers were the most vulnerable to attack whilst snorkellers constituted only 9% of the number of people attacked. There were no reports of unprovoked attacks on scuba divers in 2015.
The ISAF has been run from the Florida Museum of Natural History since 1988 and is the longest running database on shark attacks globally. As well as curating worldwide shark attack information, the ISAF also provides regular advice on shark attacks issues.
Tuesday, 9 February 2016
Sunday, 7 February 2016
Sustainability of shark fisheries on the Great Barrier Reef
The Great Barrier Reef Marine Park (GBRMP) is known worldwide as a natural wonder: a protected underwater haven for tropical fish, sharks and other marine fauna. However, only 33% of this marine protected area is closed to commercial fishing activities - within the rest of the park commercial fishing boats are allowed to operate and to carry out large scale fishing activities such as trawling and gill netting.
This is not to say that these activities are allowed to happen unchecked, however. Commercial fishing within the park operates under strict zoning rules and, as with most commercial fisheries there are maximum fishing quotas and possession limits in place.
The difficulty with any type of commercial fishing activity is assessing whether the existing marine populations truly can bear the brunt of the fishing activity. The ocean is a huge area and species are typically wide ranging, making accurate assessment of animal numbers difficult.
In recent study published in Fisheries Research a team of researchers have discovered that some commercial fishing activities within the GBRMP may not be sustainable.
The study focused on tagging and assessing the three most commonly harvested sharks in the GBRMP: the Australian blacktip shark (Carcharhinus tilstoni), the Spot-tail shark (Carcharhinus sorrah), and the Spinner shark (Carcharhinus brevipinna). The Pigeye shark (Carcharhinus amboinensis) and the Australian Sharpnose shark (Rhizoprionodon taylori) were also included as two example of non-target species. In total, 3,413 sharks were tagged during the course of the study.
Whilst the team discovered that harvest rates were highest for the Pigeye shark it was summarised that the numbers were still around the acceptable optimal equilibrium harvest rate for this species. Only a small amount of the population of this stock were vulnerable to commercial fishing activity and therefore the species may be able to withstand greater fishing pressure. However such high harvest rates for this species are surprising as it is not a target species and is instead being caught as bycatch by fishing boats.
The more worrying outcome of the study was that whilst the annual harvest rate was lower for Australian Blacktip sharks than for Pigeye sharks, the current level of exploitation of this species could be too high. This is owing to 2 main factors: the population of Blacktip sharks in the GBRMP is thought to have a lower reproductive rate than populations from northern Australia making it more difficult for stocks to replenish themselves, and this species is available to commercial fisheries from age 0 meaning that all of the population can be fished at any stage of their life cycle.
Whilst these findings can only make assumptions about localised depletion of the study species within the GBRMP, the results are important and further research and monitoring is essential to ensure that fish stocks remain healthy in this marine protected area.
Harry et al. (2016) Assessment of a data-limited, multi-species shark fishery in the GreatBarrier Reef Marine Park and south-east Queensland
This is not to say that these activities are allowed to happen unchecked, however. Commercial fishing within the park operates under strict zoning rules and, as with most commercial fisheries there are maximum fishing quotas and possession limits in place.
The difficulty with any type of commercial fishing activity is assessing whether the existing marine populations truly can bear the brunt of the fishing activity. The ocean is a huge area and species are typically wide ranging, making accurate assessment of animal numbers difficult.
In recent study published in Fisheries Research a team of researchers have discovered that some commercial fishing activities within the GBRMP may not be sustainable.
The study focused on tagging and assessing the three most commonly harvested sharks in the GBRMP: the Australian blacktip shark (Carcharhinus tilstoni), the Spot-tail shark (Carcharhinus sorrah), and the Spinner shark (Carcharhinus brevipinna). The Pigeye shark (Carcharhinus amboinensis) and the Australian Sharpnose shark (Rhizoprionodon taylori) were also included as two example of non-target species. In total, 3,413 sharks were tagged during the course of the study.
Whilst the team discovered that harvest rates were highest for the Pigeye shark it was summarised that the numbers were still around the acceptable optimal equilibrium harvest rate for this species. Only a small amount of the population of this stock were vulnerable to commercial fishing activity and therefore the species may be able to withstand greater fishing pressure. However such high harvest rates for this species are surprising as it is not a target species and is instead being caught as bycatch by fishing boats.
The more worrying outcome of the study was that whilst the annual harvest rate was lower for Australian Blacktip sharks than for Pigeye sharks, the current level of exploitation of this species could be too high. This is owing to 2 main factors: the population of Blacktip sharks in the GBRMP is thought to have a lower reproductive rate than populations from northern Australia making it more difficult for stocks to replenish themselves, and this species is available to commercial fisheries from age 0 meaning that all of the population can be fished at any stage of their life cycle.
Whilst these findings can only make assumptions about localised depletion of the study species within the GBRMP, the results are important and further research and monitoring is essential to ensure that fish stocks remain healthy in this marine protected area.
Harry et al. (2016) Assessment of a data-limited, multi-species shark fishery in the GreatBarrier Reef Marine Park and south-east Queensland
Tuesday, 2 February 2016
The Sharksafe barrier - an ecological way to keep sharks away from beaches!
The Sharksafe barrier has been causing quite a bit of fuss amongst shark enthusiasts as it has been promised to provide an environmentally friendly way to exclude sharks from swimming beaches. Now it's success has been proven as a team of researchers has successfully tested the barrier with live sharks.
Currently, shark netting (where nets are strung close to swimming areas to try and protect the public from sharks) is in effect in New South Wales and Queensland in Australia and Kwa-Zulu Natal in South Africa. Existing shark nets do not simply exclude sharks from swimming beaches; instead the intention is that the sharks will become entangled in the nets and die. The impact of shark nets is not limited to sharks either as dolphins, dugongs, turtles, whales and other marine fauna are often found dead in these nets (if you are interested in reading an in depth analysis hop along to The Shark Post - The Truth About Shark Nets). As well as shark netting, governments sometimes employ other techniques to try and reduce shark attacks near public beaches such as drumlines or shark culls.
None of the activities above are successful in completely excluding sharks from the waters around public beaches, and they have all have a detrimental impact on other marine fauna.
In their work the researchers deployed the Sharksafe barrier around Gansbaai, South Africa - a region commonly populated with Great White Sharks (Carcharodon carcharias). The barrier was equipped with artificial kelp and electro-sensory magnets to see if these additional stimuli would elicit further changes in the swimming behaviour of the great whites. Great whites have been observed to show reluctance to enter kelp forest and the researchers had success with repelling bull sharks with magnets in previous studies (The Shark Post - Magnets could be used to successfully repel bull sharks).
The Great Whites showed a strong aversion to swimming between the regions with additional stimuli and a general avoidance of the Sharksafe barrier. In addition to this the barrier is ecologically friendly as no changes to the behaviour of the Cape Fur Seals which inhabit the area was noted, and unlike shark nets marine animals will not get entangled in the more rigid structure of the Sharksafe barrier.
Whilst further studies will be needed to see the best way to utilise the barrier to ensure total exclusion of Great Whites from swimming beaches, these results are positive and lend hope to a more ecological friendly way to ensure swimmer safety in the future.
Connell, C., Andreotti, S., Rutzen, M., Meyer, M., Matthee, C. and He, P. (2014) Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies. Journal of Experimental Marine Biology & Ecology. 460.
Tuesday, 21 July 2015
Mick Fanning's media feeding frenzy - who's the real victim here?
Earlier this week my newsfeed was inundated with posts about Mick Fanning's recent encounter with a shark in South Africa, For those who might have missed it, 3 times surfing champion Mick Fanning was competing in the J-Bay Open surfing competition in South Africa when a shark popped up next to him and snagged his leash. As the shark dived, the leash was broken and Mick was knocked off his board; he was picked up by rescue boats which were laid on for the event and whisked off to safety. You can review the whole thing here.
Whilst a shark popping up at a pro surfing event is most definitely news worthy, the real news in this story is how sensationalised this event seems to have become. Once again the media appears to have taken this as an opportunity to showcase sharks in a bad light. The Australian reported that a "large shark stalked and attacked" the champion surfer, The Guardian claims that Fanning "fought off a shark attack" whilst a host on Fox News suggested that officials should be clearing the waters of sharks before an event of this nature!
It may feel as though these over hyped media pieces are all just a bit of fun but in reality they are having a detrimental effect on how the world views sharks. At a time when global shark populations are so vulnerable owing to over fishing and hunting for shark fin soup, shark conservation needs all the public support it can get. Journalists should also have a moral responsibility to report accurately on events, instead of sensationalising their articles in an attempt to get newspapers off the shelf.
Whilst accurate global shark attack statistics are tricky to pin down, the Department of Ichthyology at the Florida Museum of Natural History is attempting to do so with their International Shark Attack File. In 2014, they documented just 3 fatalities from unprovoked shark attacks - and whilst that may seem like 3 too many, if you compare this figure to fatalities from road traffic accidents, alcohol or tobacco, the risk of dying from a shark attack pales into insignificance. Yet most people's perception of the risk of being killed by a shark is much higher owing to the poor media image given to these animals.
In fact, the bad light cast on sharks by the media is so detrimental to their conservation that researchers at the University of Sydney and the Mote Marine Laboratory's Center for Shark Research in Florida have now proposed a new classification system to describe all shark interactions. Currently the majority of news articles which involve sightings or encounters with sharks will be touted as an "attack" - even if the shark simply swims up to someone then swims away. For the sake of accurate reporting, the Neff-Heuter study group has proposed 4 new terms to be used for all shark encounters: Shark sightings, Shark encounters, Shark bites and Fatal shark bites. In this way they hope to separate fact from hype and ensure that the public gets the most accurate record of events.
Thankfully the majority of people who use the oceans - divers, surfers, swimmers - recognise that we are the visitors in the shark's world and are advocates for protecting the marine environment - including the species which live there. This still doesn't excuse sloppy media reporting and an attempt to villify a group of species simply to sell papers.
Whilst a shark popping up at a pro surfing event is most definitely news worthy, the real news in this story is how sensationalised this event seems to have become. Once again the media appears to have taken this as an opportunity to showcase sharks in a bad light. The Australian reported that a "large shark stalked and attacked" the champion surfer, The Guardian claims that Fanning "fought off a shark attack" whilst a host on Fox News suggested that officials should be clearing the waters of sharks before an event of this nature!
It may feel as though these over hyped media pieces are all just a bit of fun but in reality they are having a detrimental effect on how the world views sharks. At a time when global shark populations are so vulnerable owing to over fishing and hunting for shark fin soup, shark conservation needs all the public support it can get. Journalists should also have a moral responsibility to report accurately on events, instead of sensationalising their articles in an attempt to get newspapers off the shelf.
Whilst accurate global shark attack statistics are tricky to pin down, the Department of Ichthyology at the Florida Museum of Natural History is attempting to do so with their International Shark Attack File. In 2014, they documented just 3 fatalities from unprovoked shark attacks - and whilst that may seem like 3 too many, if you compare this figure to fatalities from road traffic accidents, alcohol or tobacco, the risk of dying from a shark attack pales into insignificance. Yet most people's perception of the risk of being killed by a shark is much higher owing to the poor media image given to these animals.
In fact, the bad light cast on sharks by the media is so detrimental to their conservation that researchers at the University of Sydney and the Mote Marine Laboratory's Center for Shark Research in Florida have now proposed a new classification system to describe all shark interactions. Currently the majority of news articles which involve sightings or encounters with sharks will be touted as an "attack" - even if the shark simply swims up to someone then swims away. For the sake of accurate reporting, the Neff-Heuter study group has proposed 4 new terms to be used for all shark encounters: Shark sightings, Shark encounters, Shark bites and Fatal shark bites. In this way they hope to separate fact from hype and ensure that the public gets the most accurate record of events.
Thankfully the majority of people who use the oceans - divers, surfers, swimmers - recognise that we are the visitors in the shark's world and are advocates for protecting the marine environment - including the species which live there. This still doesn't excuse sloppy media reporting and an attempt to villify a group of species simply to sell papers.
Sunday, 1 March 2015
Shark news - Gulper shark specimen caught off the coast of Norway
The specimen was caught on longlines set by a commercial fishing vessel and has been deposited at the University Museum of Bergen. Owing to the fact that most sharks are poikilothermic (have no way of regulating their internal body temperature) there are very few examples of sharks inhabiting the polar regions. The blackmouth catshark (Galeus melastromus), the velvet belly (Etmopterus spinax) and the greenland shark (Somniosus microcephalus) are the only other 3 species commonly encountered this far north.
The little gulper shark inhabits water up to 1,400 m in depth and feeds on bony fish and squid. Very little is known about the biology of this shark and the taxonomy is in need of revision. In the IUCN Red List, there are 12 species of gulper shark listed of which 3 are considered Vulnerable, 2 Near Threatened, 1 Endangered, 5 Data Deficient and only 1 Least Concern.
Whilst this is the first confirmed sighting of this species this far north, it is not yet known if this is simply a stray individual or an indication of the expansion of this species into colder waters.
References
Monday, 23 February 2015
Shark Research - Whale Shark Genome Just As Big As The Human Genome!
The estimated genome size of the whale shark was 3.44 gigabases (Gb) which puts it on par with our own genome (Homo sapien) at 3.3Gb (1). One barrier to sequencing the genomes of cartilaginous fish is that their estimated genomes tend to be rather large; the genome of only one other cartilaginous fish, the elephant shark (Callorhinchus milii), has been sequenced and this was an attractive candidate for genome sequencing as its predicted genome was less than 1Gb (2). Genetic data for a bony fish, the rainbow trout (Oncorhynchus mykiss), is also available and at 1.9Gb this genome is smaller than that of the whale shark (3).
Using predictive software, the researchers estimated that the whale shark genome has 23,594 protein coding genes, which is very similar to the human genome which has 20,000-25,000 protein coding genes. As might be expected,the smaller genome of the elephant shark has only 18,872 protein coding genes.
Genomic studies like this are important as they not only help us understand more about how the underlying genetic code works to make an entire organism function, but they can also be used to deduce the evolutionary relationships between organisms with a greater degree of accuracy than morphological data. Genetic analysis of whale sharks has already proven that there is not just one global population of whale sharks - as was previously thought - but at least 2, genetically distinct populations.
Whilst this genome is just at the draft stage, the researchers hope to secure funding to continue their work and delve deeper into the genetic data of the whale shark in order to help us learn more about this ocean giant - so watch this space!
The draft genome is available at http://whaleshark.georgiaaquarium.org/.
Wednesday, 11 February 2015
Shark news - Shark Sanctuary Created in Madagascar!
The Government of Madagascar have created their first ever shark sanctuary in Antongil Bay, North West Madagascar. Covering 3,750km2 of ocean, the Order has been put in place after lengthy consultation with fisheries, community fishermen, local authorities and NGOs and will protect this extremely rich area of biodiversity.
The Order aims to empower village communities to manage their fishing activity, whilst ensuring that any exploitation of the fisheries resource is carried out sustainably and has three main objectives:
1) The preservation of the environment to ensure the sustainability of the ecosystem
2) The establishment of a sustainable fishing resource to improve the living standards of coastal populations in general and fishermen in particular, and
3) More equitable distribution of wealth created by fisheries by enhancing the part of the local population against the interests of the municipal economy, regionally and nationally
Whilst sustainable fishing is encouraged within the sanctuary, shark fishing has been entirely banned. 19 species of shark are found in Antongil Bay of which over a third are threatened with extinction.
The announcement was made jointly with the Wildlife Conservation Society (English) and the Ministry of Marine Resources and Fisheries Madagascar (French)
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| The area of the shark sanctuary. Image from Mongabay |
1) The preservation of the environment to ensure the sustainability of the ecosystem
2) The establishment of a sustainable fishing resource to improve the living standards of coastal populations in general and fishermen in particular, and
3) More equitable distribution of wealth created by fisheries by enhancing the part of the local population against the interests of the municipal economy, regionally and nationally
Whilst sustainable fishing is encouraged within the sanctuary, shark fishing has been entirely banned. 19 species of shark are found in Antongil Bay of which over a third are threatened with extinction.
The announcement was made jointly with the Wildlife Conservation Society (English) and the Ministry of Marine Resources and Fisheries Madagascar (French)
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