A
new analysis of global fishing data has found the world’s fishing fleet doubled
in size over the 65 years to 2015 but for the amount of effort expended the
catch fell more than 80 per cent.
Published
in the journal Proceedings of the National Academy of Sciences, the study by researchers from the University of
Tasmania and CSIRO found the global fishing fleet grew from 1.7 million vessels
in 1950 to 3.7 million in 2015.
However,
despite better technology and increased motorisation, modern fishing vessels
take only one-fifth of the catch per unit of effort (CPUE) that the 1950s
fishing fleet achieved.
Institute
for Marine and Antarctic Studies (IMAS) and Centre for Marine Socioecology (CMS) PhD student Yannick Rousseau, who led the study, said
the findings reflect growing pressure on marine resources and a fall in the
abundance of fish.
“What
we have seen over the last 65 years are more and more fishing vessels chasing
fewer fish,” Mr Rousseau said.
“Since
1950 a dramatic increase in the size of the fishing fleet in Asia has more than
offset small declines in North America and Western Europe.
“Most
of the increase in vessel numbers has been in motorised fishing boats, a change
from the unpowered ‘artisanal’ fishing vessels that once characterised Asian
and African fishing fleets.
“But,
despite its advanced technology and increased numbers, the modern motorised
fleet is having to work much harder to catch fewer fish,” he said.
Mr
Rousseau said fisheries scientists use a measure of catch per unit of effort
(CPUE) to assess fisheries management and the well-being of fish stocks.
“CPUE
reflects how many fish are caught for the amount of effort expended, such as
during a day’s fishing, and this measure paints a dark picture of the state of
the ocean’s resources.
“In
recent years a sharp drop in CPUE in Southeast Asia, Latin America and the southern
Mediterranean indicates their fisheries expanded at a much faster rate than
fish stocks could support.”
The study found that in developed
countries such as Australia more effective fisheries management and a sharp
fall in the size of the fishing fleet over the last decade has led to a recent
stabilisation of CPUE.
“However,
on current worldwide trends we can expect to see a further one million vessels
on the water by mid-century, and the average engine power of the global fleet
continues to increase,” Mr Rousseau said.
“These
changes will further challenge the sustainable use of fisheries resources.
“This
is a particular concern for populations in regions such as Southeast Asia,
where a high proportion of people rely on fish for sustenance.
“Our
findings suggest that additional management measures are urgently warranted to
ensure the future sustainability of global marine resources,” Mr Rousseau said.
