Tim Cashion, lead author of the study and a researcher with the Sea Around Us initiative at UBC’s Institute for the Oceans and Fisheries, noted:

Industrial fisheries do not bring everything they catch to port. During the period we studied, they threw out over 750 million tonnes of fish and 60 per cent of that waste was due to bottom trawlers alone.



  • Fishing gear is assigned for large-scale and small-scale fisheries catches globally.
  • Bottom trawls and purse seines account for over 53% of all catches.
  • Bottom trawls account for nearly 60% of fisheries discards.
  • Small-scale fisheries have a higher landed value than any single industrial gear.

Bottom trawls are large nets that industrial fishing vessels drag along the seabed. As explained, they capture everything including deep-sea corals and sponge beds and perfectly good fish, but not the ones the fishers are looking for. This fishing method generates the most waste because and the unwanted catch is dumped back into the ocean.

To reach this conclusion, Cashion and his colleagues identified the fishing tools used by industrial and artisanal fisheries in each maritime country and territory and paired them with the millions of records in the Sea Around Us catch database that include reported and unreported catches by fishing country, fishing sector, year and species.

They found that, globally, industrial and artisanal fisheries caught 5.6 billion tonnes of fish in the last six and a half decades. While almost 28% of that catch was captured by industrial bottom trawl, this fishing technique accounts for nearly 60% of fisheries discards. Deng Palomares, co-author of the study and the Sea Around Us Project Manager, said:

They threw away fish that, even though are not the most valuable, are perfectly good for human consumption. Had they landed that catch, they would have made $560 billion according to our prices dataset. The worst part is that, in general, bottom trawlers are so expensive to operate that the only way to keep them afloat is by giving them government subsidies. In other words, it’s a wasteful and inefficient practice.

Palomares added that, conversely, all small-scale fisheries combined were responsible for only 23% of the global catch or approximately 1.3 billion tonnes in the past 65 year, but their catch was worth significantly more because they use small gillnets, traps, lines, hand tools, and similar utensils to catch specifically what they want.

Catching fewer quantities of higher-value species, such as crabs and lobsters, they made almost $200 billion.

Co-author Daniel Pauly, who is the principal investigator of the Sea Around Us, added:

This information can also be used to boost artisanal fisheries. As the data show, with very little infrastructure and support they already generate more value. If, based on these results, artisanal fisheries received the $35 billion in subsidies that industrial fisheries get every year, they would be able to employ more people than they already do, take better care of their catch, supply specialized markets with a superior product and provide nutritious food for the communities where they operate, all of this while reducing the amount of fish that are discarded or turned into livestock feed.

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