Industrial fishing fleets dump nearly 10 million
tonnes of good fish back into the ocean every year,
according to new research.
The study by researchers
with Sea Around Us, an initiative at the University
of British Columbia’s Institute for the Oceans and
Fisheries and the University of Western Australia,
reveals that almost 10 per cent of the world’s total
catch in the last decade was discarded due to poor
fishing practices and inadequate management.
This is equivalent to
throwing back enough fish to fill about 4,500
Olympic sized swimming pools every year.
Fishers discard a
portion of their catch because fishing practices
damage the fish and make them unmarketable, the fish
are too small, the species is out of season, only
part of the fish needs to be harvested — as with the
Alaska pollock roe — or the fishers caught species
that they were not targeting, something known as
“Discards also happen
because of a nasty practice known as high-grading
where fishers continue fishing even after they’ve
caught fish that they can sell,” said Dirk Zeller,
lead author for the study who is now a professor at
the University of Western Australia and senior
research partner with the Sea Around Us.
“If they catch bigger
fish, they throw away the smaller ones; they usually
can’t keep both loads because they run out of
freezer space or go over their quota.”
The study examined the
amount of discarded fish over time.
In the 1950s, about five
million tonnes of fish were discarded every year, in
the 1980s that figure grew to 18 million tonnes.
It decreased to the
current levels of nearly 10 million tonnes per year
over the past decade.
The decline in discards
in recent years could be attributed to improved
fisheries management and new technology, but Zeller
and his colleagues say it’s likely also an indicator
of depleted fish stocks.
A 2016 reconstruction of
catch data from 1950 to 2010 by researchers with the
Sea Around Us revealed that catches have been
declining at a rate of 1.2 million tonnes of fish
every year since the mid-1990s.
“Discards are now
declining because we have already fished these
species down so much that fishing operations are
catching less and less each year, and therefore
there’s less for them to throw away,” he said.
Zeller and his
colleagues Tim Cashion, Maria Palomares and Daniel
Pauly, say that the study also shows how industrial
fleets move to new waters once certain fisheries
“The shift of discards
from Atlantic to Pacific waters shows a dangerous
trend in fisheries of exporting our fishing needs
and fishing problems to new areas,” Cashion said.
Most of a fish is discarded by the fisheries
For more information
Global marine fisheries discards: a synthesis of
Fish & Fisheries
reconstructions reveal that global marine fisheries
catches are higher than reported and declining.
University of British Columbia
University of Western Australia