Just under 2% of all fishing gear in the world makes its way into the oceans annually, new research has found. That’s over 78,000 km2 of nets, almost 740,000 km of longlines and more than 25 million pots and traps. Every single year.
For context, the city of Melbourne with its five million people is 9,993 km2!
A collaboration of researchers from the University of Tasmania and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) interviewed 451 fishers from seven countries (in Africa, Asia, the Caribbean, Europe, North America, Oceania and South America) in an effort to understand how much of their gear they lost to the ocean each year.
From these data, they were able to estimate the amount lost globally by multiplying by global fishing effort data. They found there was an overall loss globally of fishing gear of 1.82% of gear.
Not all of it is lost – some is abandoned or discarded – but all Abandoned, Lost, or otherwise Discarded Fish Gear (ALDFG) – sometimes referred to as ‘ghost nets’, represents a major contribution to ocean pollution and has social and economic impacts as well as serious environmental consequences including loss of marine and coastal habitats and wildlife.
The researchers were able to gather information on what types of gear were lost more often. They found that on average, 3.94% of all bottom trawl nets, 3.58% of all longline branchlines and 2.86% of all longline hooks were lost globally every year. 0.74% of all pots and traps are lost annually.
Until now, writes Dr. Kelsey Richardson and coauthors, “empirical information on how much fishing gear is lost to the oceans has been limited, despite an outdated ill-quoted estimate of 640,000 metric tons lost each year.
Some of the measures already taken to reduce the impacts of ALDFG include gear marking and tracking, loss reporting and recovery and improving facilities for dealing with fishing gear at the end of its useful life along with strategies to minimise the effect of pollution events and regulation of destructive fishing practices.
The research is an important step in establishing a baseline to help inform ongoing interventions targeting ALDFG.OCEANS STORIES:
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Clare Kenyon is a science journalist for Cosmos. An ex-high school teacher, she is currently wrangling the death throes of her PhD in astrophysics, has a Masters in astronomy and another in education. Clare also has diplomas in music and criminology and a graduate certificate of leadership and learning.
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