Shipwrecks can provide an important refuge for marine life in areas subject to heavy fishing pressure, despite being an unnatural part of the ecosystem.
Bottom trawling, which involves dragging nets across the seafloor, has a devastating impact on biodiversity, destroying whole ecosystems and pulling up many animals that weren鈥檛 intended to be caught.
However, fishing boats that use this practice often avoid shipwrecks, as they can represent a danger to the boat and gear.
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鈥淪hipwrecks provide an area of high habitat complexity and a refuge for many species unable to survive in a heavily trawled environment, potentially species of conservation priority as well,鈥� says at the University of Plymouth in the UK.
Hickman and her colleagues used video cameras to measure the abundance of species present in five shipwrecks off the east coast of Scotland, some of them in areas subject to intensive fishing and others in protected areas. In areas where bottom trawling is permitted, they found 240 per cent more marine life at wreck sites than at comparison sites. Nearby, within 50 metres of the shipwrecks, the number of animals found was 340 per cent higher than at comparison sites.
In areas where trawling is prohibited, organisms were 149 per cent more abundant at comparison sites than they were on wrecks.
鈥淎 lot of different species were taking refuge in the shipwrecks, including anemones, starfish, crustaceans and fish,鈥� says Hickman. 鈥淪ome species were definitely found to be more reliant on the wrecks, many of which play important roles in marine ecosystems.鈥�
The study suggests that shipwrecks should be considered as structures worth protecting, opening up new approaches for marine conservation.
鈥淲hilst shipwrecks are not a natural habitat and cannot be considered a suitable substitute for well-protected natural habitats, they do seem to be providing ecological benefits in heavily impacted areas,鈥� says Hickman.
Marine Ecology
