Study reveals potential solution to whale entanglements in South Africa

Posted by Taylah Strauss on 23 November 2021

A World Wildlife Fund (WWF) funded study conducted by University of Cape Town researcher Michael Daniel and Associate Professor Colin Attwood revealed that ropeless fishing techniques could be the solution to reducing whale entanglements in South Africa.

A humpback whale

Trap fisheries are typically used for catching rock lobster and octopus. Whilst effective, it often comes at the detriment of marine life, as these free-floating ropes on the water surface and ocean floor allow whales to get entangled in them.

Bryde’s whales are particularly vulnerable to entanglement in these trap fishing ropes, as they dive deep and fast to catch their food. The southern right and humpback whales are also at risk, due to their inquisitive nature which prompts them to investigate floating objects such as rope and kelp.

Ropeless fishing devices allow for traps to be deployed in waters without a surface buoy acting as a location beacon. Instead, the buoy will only be deployed when it’s time to remove the trap, thus avoiding the risk of ropes floating in the water for extended periods of time.

Techniques for deploying a buoy range from simplistic galvanized release to a more technical release, with varying costs accompanying each option. However, the study found that ropeless fishing techniques would be economically feasible, with only a 5% estimated increase in cost at most.

The Department of Forestry, Fisheries and the Environment placed a temporary ban on experimental octopi’s fishery in False Bay in 2019, following numerous whale deaths resulting from rope entanglements. The suspension was lifted, provided that fishers implement techniques to avoid whale entanglements. The fisheries in False Bay has been using ropeless fishing techniques as of 2020 and has not had a whale entanglement since then, which is a testament to the success of ropeless fishing techniques in avoiding whale deaths.

Picture: Mike Doherty/Unsplash


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