Shark nets – what’s the catch?
DID YOU know that the shark nets along the KwaZulu-Natal coast do not prevent sharks from reaching the surf zone on swimming beaches?
Luckily, it is highly unlikely that you will ever be attacked by a shark. So unlikely, in fact, that the odds of dying from a shark attack in South Africa are one in 878 956.
For decades, the human fear of sharks has transcended logic and statistics. You are more likely to have a coconut fall on your head than be attacked by a shark!
Shark nets are not actually barriers but are staggered 300m and 500m parallel from the shore with gaps between and below them. Each net is usually 214m long and 6m deep, with a stretched mesh of 51cm, and is secured at each end by two anchors. Sharks can therefore swim under, around and between them to reach the surf zone. The nets are a form of fishing gear, called gill nets, which work by trapping sharks by their gills once they have pushed their heads through the net.
Unfortunately, sharks are not the only marine life that gets caught in this unselective gear. For example, in 2017, 18 turtles, 26 dolphins, 4 whales and 30 rays died in the nets.
There are currently 37 beaches along the KwaZulu-Natal coastline that have “shark safety” gear installed, owned, and maintained by the KwaZulu-Natal Sharks Board (KZNSB), with the nets supplemented by 177 drumlines. Drumlines are a more targeted form of fishing (targeting large sharks) and consist of an anchored float from which a single baited hook is suspended.
The logic behind the bather safety gear is to reduce the number of large sharks in the vicinity of bathing beaches by catching them, thus lowering the probability of encounters between large sharks and people.
Herein lies the conundrum – many of the shark species killed in the nets along our beaches are endangered (as endangered as pangolins or wild dogs). In fact, sharks and rays are arguably now one of the most endangered taxa on the planet. South Africa is one of three global hot spots for sharks and rays (with over 200 species in our waters) and could play a significant role in preventing further extinctions and aiding the recovery of these imperilled species.
Since the 1990s, the KZNSB has reduced the number of beaches “protected”, and the total number/length of nets along the coast. They are also slowly replacing nets with drumlines, which has reduced both shark mortalities and deaths of other marine animals. Although drumlines target a different group of sharks, they do not entirely solve the problem. For example, they catch an increased number of endangered juvenile dusky sharks.
For many years, KZNSB and others have been trying to develop methods for bather safety which do not kill or harm sharks, such as a shark repellent electric cable. The KZNSB has also experimented with acoustic deterrents to reduce the number of dolphin and whale entanglements in the nets, but these have not proved very effective.
The Shark Spotters programme in the Western Cape is a proudly South African example of a non-lethal solution that keeps both bathers and sharks safe. The recently launched SharkSafe Barrier system, a configuration of pipes with strong magnetic fields, has also proven to be a strong deterrent for shark species.
Unfortunately, due to KZN’s open and high energy coastline, these alternatives are not currently viable here, but this certainly does not mean that additional options should not continue to be explored.
Furthermore, to reduce shark and dolphin catches associated with the sardine run and the entanglement of humpback whales during their annual migration from the Southern Ocean, the KZNSB remove the nets, while replacing with drumlines, from most beaches between May and July every year.
This has proven to be extremely effective in reducing catches and perhaps may pave the way for a permanent protocol of removing the nets along the entire KZN coast for the full duration of the sardine run and whale migration (June to November).
However, as South Africans we can do better. It is time to shift the mindset of our beach-goers, tourists, and officials, have discussions over viable bather safety gear alternatives and, most importantly, we require political will.
What is needed is a new long-term strategy for the KZNSB, investment and dedication into the implementation of non-lethal alternatives for KZN, the potential redeployment of staff and boats to fisheries enforcement and alternatives instead of implementation of a harmful fishery, responsible tourism, and focused education on the environmental and tourism benefits of our sharks.
There is strong scientific evidence proving how important our sharks are in balancing our ocean ecosystem. Surely, we as humans entering the ocean should be modifying our behaviour to sensibly avoid contact with them and to protect them rather than trying to eradicate them.
And, given that the shark safety gear essentially provides a false sense of security to bathers – are they worth the risk to the existence of iconic keystone species in our ocean?
| Dr Jennifer Olbers, WILDTRUST Scientist: WILDOCEANS Programme
To read the full version of this piece go to http://wildtrust.co.za/shark-nets-whats-the-catch/