Adequacy of Shark Nets

This research examines the adequacy of shark nets in reducing shark attacks and the impact on marine species as bycatch. Findings suggest concerns about the effectiveness of shark nets and the need to resolve the issue of bycatch.

Running head: ADEQUACY OF SHARK NETS
ADEQUACY OF SHARK NETS
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1ADEQUACY OF SHARK NETS
Abstract
Shark nets are submerged nets designed to capture sharks and minimise shark attacks. The aim of
this research is to study the adequacy of shark nets in reducing the shark attacks. Most of the
crowded beaches in Australia have experienced shark attacks. Shark attacks are frequent,
especially in the case of surfers and swimmers. There were many cases reported regarding shark
bite and shark attacks. To reduce the interaction between shark and beachgoers, shark nets were
introduced by the government around crowded beaches. After the installation of shark nets, the
number of shark attacks reduced rapidly. However, concerns have been raised about the
effectiveness of shark nets. Instead of sharks there are many other marine species which also
frequently become the bycatch. Mortality of these marine species is a loss to the ecosystem and
is a serious issue that need to be resolved.

2ADEQUACY OF SHARK NETS
Table of Contents
Abstract......................................................................................................................................1
Table of Contents.......................................................................................................................2
1. Introduction........................................................................................................................3
2. Analysis...............................................................................................................................4
2.1 Human safety -Do shark nets really protect humans from shark attacks?............4
2.2 Shark nets bycatch - are sharks the only victim of shark nets?............................6
3. Conclusion..........................................................................................................................8
4. Reference............................................................................................................................9

3ADEQUACY OF SHARK NETS
1. Introduction
Shark bites are common and are observed frequently in beaches. The Recife’s
metropolitan region in Brazil has experienced high shark attack rates, between 1992 and 2011.
Fifty-five incidents were noted regarding the shark attacks (Hazin & Afonso, 2014). To reduce
the death rate by shark attacks, a strategy was introduced by the government. Under this strategy,
shark nets were introduced to kill sharks. It is a submerged net placed around crowded beaches
mostly to protect beachgoers. Different types of shark nets are used, one of which is gillnets
which targets the sharks and capture them by entanglement. Not only sharks, but other marine
species also get entangled in the gillnets. About 74% odontocete species, 66% pinnepeds, 64%
mysticetes, sirenians and mustelids become the bycatch of gillnets over the past 20 years (Atkins,
2016).

4ADEQUACY OF SHARK NETS
2. Analysis
2.1 Human safety -Do shark nets really protect humans from shark attacks?
Unprovoked attacks by sharks is the biggest fear of human, especially in case of
beachgoers. Most of the number of people getting injured or killed due to shark attacks are
swimmers and surfers. According to Lemahieu et al. (2017), between 2011 and 2013, eight
people were killed by the shark bites in Reunion Island’s West Coast. There were many cases
reported regarding shark attacks. To reduce the rate of attacks by shark, shark nets were
introduced by the government. It was designed to kill sharks by entangling them into shark nets.
It is placed around the beaches to minimise the contact between human and shark (Shark
management, 2019). After the installation of shark nets in beaches, the number of shark attack is
reduced drastically (Gibbs & Warren, 2015). As stated above, shark nets were introduced to kill
sharks, but it failed to do so. It only captures shark by entangling them in the shark nets. Hence, a
new strategy was proposed by the government that works on the principle of capture and kill.
This strategy is named as “shark hazard mitigation strategy” (Department of premier and cabinet,
2019). Under this strategy, they were killed cruelly by the people after capturing them.
According to a study done by Gibbs and Warren (2014), on January 24, 2014, after capturing a
3m Tiger Galeocerdocuvier (Tiger Shark), it was killed brutally by shooting four times by the
rifle in the shark’s head by the government’s employee and then the body was dumped
alongshore. Although the number of people getting injured is minimised, shark nets do not
provide full protection against shark bites. To lessen the interaction between shark and beach-
goers some other techniques are also introduced by the government known as shark culling and
shark spotting (Curtis, 2012). This strategy imposed negative impact on the demographic
population of shark. As high rate of shark killing destroys the marine ecosystem, but neither the

5ADEQUACY OF SHARK NETS
government nor the local people consider it a serious issue. According to Gibbs and Warren
(2015), public perception about killing shark is in favour of the government. Beach-goers often
encounter sharks and to minimise the risk of shark bites and shark attacks; they support the
program initiated by the shark hazard management to capture and then kill the sharks. According
to a study done by Neff and Yang (2013), in 1996 a survey was conducted based on shark
killing. At that time out of total respondents, only 30% mentioned that shark killing is a major
issue. Another survey conducted in 2003 have an opposite result, it was found that 80% of the
respondents feel that the population of shark is too high and they must be killed to protect
humans. A survey was conducted by the government about the attitude of people towards shark
nets. The survey was done over phone and online. From the result obtained by the survey, it can
be concluded that there are very less number of supporters of shark nets as compared to that of
the people that opposes the strategy (Department of primary industries, 2019).
Figure: Diagrammatic representation of survey done based on people’s attitude towards shark
nets

6ADEQUACY OF SHARK NETS
Source: (Department of primary industries, 2019)
2.2 Shark nets bycatch - are sharks the only victim of shark nets?
Shark nets are invented to either kill sharks or to capture them by entanglement and
minimise the number of shark attacks (Shark management, 2019). Even though it is designed to
catch sharks, they are not the only victim. There are many other endangered water species which
becomes by-catch in these nets. In a study done by Atkins, Cliff and Pillay (2013), it is
mentioned that instead of a shark, Sousa plumbea (Humpback Dolphins) are caught multiple
times in KwaZulu-Natal province of South Africa. By these, the mortality rate of humpback
dolphins has increased rapidly, making it an endangered species. There are many endangered and
threatened species such as dolphins, dugongs, whales and sea turtles which becomes frequent
bycatch. Another study conducted by Lane et al. (2014), suggests that in KwaZulu-natal Coast of
South Africa, five Indo-Pacific Sousa plumbea (Humpback Dolphins) and thirty-five Indian
ocean Tursiopsaduncus (Bottlenose Dolphins) between 2010 and 2012. Apart from that, there are
some species of sharks which are counted into endangered and threatened species that are getting
killed by shark nets, which is a massive loss to the ecosystem. In a study conducted by
O’Connell et al. (2014), it is mentioned that shark nets have impacted negatively on the
migratory and local shark population. Carcharodon carcharias (White shark) is a protected
species, that suffers from mortality after installation of shark nets. Neophocacinerea (Australian
sea lions) is one also one of the protected species having small breeding colonies. These sea lions
are one of those marine species that becomes the frequent by-catch of shark nets and is now on
the verge of becoming threatened species (Hamer et al. 2013). To examine the rate of bycatch,
two shark net trial was performed by the government. In the first shark net trial, only nine sharks

7ADEQUACY OF SHARK NETS
were caught, whereas the number of bycatch is 266. In the second trial, only 2 sharks were
captured and 143 other animals were caught (Department of primary industries, 2019). From the
result obtained by conducting the survey, it can be concluded that the number of bycatch is more
than that of target animals.
Figure: Number of bycatch in shark net trials
Source: (Department of primary industries, 2019)

8ADEQUACY OF SHARK NETS
3. Conclusion
From the above report, it can be concluded that the cases of shark bites are prevalent in
Australia, and many beachgoers were heavily injured or killed by these attacks. To lower the rate
of shark attacks, shark nets are introduced by the government. The outcome of these gillnets
were found to be less effective as they were only getting entangled but not killed. Hence, another
strategy was formulated named as shark hazard mitigation strategy. According to this strategy,
sharks were only captured by using these nets and are killed afterwards. This strategy is proved
to be more effective in killing sharks, but sharks are not the only one to get entangled in the nets.
A Huge number of other species becomes bycatch of the net and get killed. The Death rate of
marine species increased after the installation of these nets, which damages the marine
ecosystem.

9ADEQUACY OF SHARK NETS
4. Reference
Atkins, S., Cantor, M., Pillay, N., Cliff, G., Keith, M., & Parra, G. J. (2016). Net loss of
endangered humpback dolphins: integrating residency, site fidelity, and bycatch in shark
nets. Marine Ecology Progress Series, 555, 249-260.
Atkins, S., Cliff, G., & Pillay, N. (2013). Multiple captures of humpback dolphins (Sousa
plumbea) in the KwaZulu-Natal shark nets, South Africa. Aquatic Mammals, 39(4), 397.
Curtis, T. H., Bruce, B. D., Cliff, G., Dudley, S. F., Klimley, A. P., Kock, A., ... & Lowe, C. G.
(2012). Responding to the risk of White Shark attack. Global Perspectives on the
Biology and Life History of the White Shark. CRC Press, 477-510.
Department of premier and cabinet. (2019). Retrieved from
https://www.dpc.wa.gov.au/publications/documents/wa%20gov
%20shms_updated180716_on%20website.pdf
Department of primary industries. (2019). North Coast shark net trial. Retrieved from
https://www.dpi.nsw.gov.au/fishing/sharks/management/shark-net-trial
Gibbs, L., & Warren, A. (2014). Killing Sharks: cultures and politics of encounter and the sea.
Australian Geographer, 45(2), 101-107. https://doi.org/10.1080/00049182.2014.899023
Gibbs, L., & Warren, A. (2015). Transforming shark hazard policy: Learning from ocean users
and shark encounter in Western Australia. Marine Policy, 58,
116-124.https://doi.org/10.1016/j.marpol.2015.04.014
Hamer, D. J., Goldsworthy, S. D., Costa, D. P., Fowler, S. L., Page, B., & Sumner, M. D. (2013).
The endangered Australian sea lion extensively overlaps with and regularly becomes
by-catch in demersal shark gill-nets in South Australian shelf waters. Biological
Conservation, 157, 386-400.

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Hazin, F. H. V., &Afonso, A. S. (2014). A green strategy for shark attack mitigation off Recife,
Brazil. Animal Conservation, 17(4), 287-296.
Lane, E. P., De Wet, M., Thompson, P., Siebert, U., Wohlsein, P., &Plön, S. (2014). A
systematic health assessment of Indian ocean bottlenose (Tursiopsaduncus) and Indo-
Pacific humpback (Sousa plumbea) dolphins incidentally caught in shark nets off the
KwaZulu-Natal coast, South Africa. PloS one, 9(9),
e107038.https://doi.org/10.1371/journal.pone.0107038
Lemahieu, A., Blaison, A., Crochelet, E., Bertrand, G., Pennober, G., & Soria, M. (2017).
Human-shark interactions: The case study of Reunion island in the south-west Indian
Ocean. Ocean Coastal Management, 136,73-8
https://doi.org/10.1016/j.ocecoaman.2016.11.020
Neff, C. L., & Yang, J. Y. (2013). Shark bites and public attitudes: policy implications from the
first before and after shark bite survey. Marine Policy, 38, 545-547.
O’Connell, C. P., Andreotti, S., Rutzen, M., Meÿer, M., Matthee, C. A., & 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 and Ecology, 460, 37-46. https://doi.org/10.1016/j.jembe.2014.06.004
Shark management. (2019). Retrieved from
https://www.dpi.nsw.gov.au/fishing/sharks/management