KOCHI: Fish stocks are depleting in shallow waters. Trawlers are moving deeper into the sea, leading to the emergence of bottom trawling as the most destructive fishing activity. To prevent the destruction of marine ecosystem, species and their habitat, marine ecologist Lisa A Levin wants countries like India to enforce regulations on bottom trawling.
Distinguished Professor and Oliver Chair with the Scripps Institution of Oceanography, University of California, Levin shared her thoughts on protection of marine ecology with Express. The US national had arrived in Kochi on invitation from the School of Marine Sciences head S Bijoy Nandan as part of the ‘scholar-in-residence’ programme organised by Cusat under the Kerala Higher Education Department’s Erudite Scheme.
The European Union has imposed a ban on bottom trawling below 800 metres and countries across the world need to bring in similar regulations to protect marine species, she said.
“We need to bring in fisheries regulations to adapt to the impacts of climate change. There is a need for ecosystem-based management as the oceans are getting warmer and acidic. Depletion of oxygen levels is threatening the fish stocks and altering the habitat of marine species,” Levin said.
According to a recent study, she said, the oceanic oxygen levels have fallen by 2 per cent since 1960s.
“There are zones in the Pacific Ocean where the levels have fallen by 20 to 30 per cent. The lower the oxygen level, the lesser the availability of big species. The size of the fish is shrinking due to climate change. We have to change the species we fish and create protected zones, giving the fish a space to build resilience,” she said.
Levin, who co-leads the Deep Ocean Stewardship Initiative, said oxygen depletion happens in the mid-depths ranging from 100 m to 1,000 m. Warm water holds less oxygen and when the ocean gets warmer it becomes more layered.
“As less oxygen reaches the deep sea, it will have far-reaching biological consequences,” she said. According to her, extreme weather conditions are the direct implications of climate change. Many parts of the world are experiencing tropical storms, cyclones and storm surge.
A rise in sea level added with a storm surge can be devastating. Island nations can encounter big problems. The Deep Sea Stewardship Initiative is bringing together experts from various fields like science, law and policy, economics, communications and technology to provide guidance on environmental management of deep ocean, Levin said.
“This is an area experiencing rapid industrialisation. Fisheries, energy extraction like deep sea oil and gas exploration, and contamination due to discharge of industrial effluents have impacted the deep ocean ecosystem. The stewardship was formed to provide expert inputs for better management. We have working groups on deep sea fishing, genetic resources and the Food and Agricultural Organisation (FAO) that manages international fisheries. We also have a working group focused on the new treaty being negotiated internationally on biodiversity,” she said.