Sink or Swim: Asia’s marine fisheries at risk of collapse, leading scientists warn

HONG KONG SAR – Media
OutReach – 3 November 2021 – The combined impacts of climate change
and overfishing mean Asia’s fisheries are at risk of collapse in the coming
decades, according to new research released today.

Photo credit:
Calton Law, further press materials available here.

The report Sink
or Swim: The future of fisheries in the East and South China Sea shows that growing demand for fish-based
feed in the aquaculture industry is an emerging driver of fisheries
overexploitation in the East and South China Seas.

Under a severe climate change trajectory, which
indicates a 2˚C warming by 2050, the South China Sea is likely to experience
significant declines in key commercial fish and invertebrate species, placing
many regional fishing economies at risk of devastating failure.

Scientists call for immediate action to reduce
fishing effort in the next ten years in order to prevent irreparable damage to
Asia’s key oceans. As the two most important fishing areas in the West Pacific
in terms of productivity and economic value, the East
and South China Seas have a combined trade valued at approximately
US$100 billion.

Parts of these marine areas have
experienced warming ten times the global average, whilst subject to decades of
overfishing. Many
commercially important species, such as chub mackerel or large yellow croakers,
are currently classified as overexploited.

The research, conducted by University of British
Columbia (UBC) fisheries scientists and ADM Capital Foundation, highlights key
threats and risks of economic losses under a range of climate change and
fisheries management scenarios.

The fisheries team applied advanced ecosystem
modelling techniques to project the impacts of climate change and overfishing
on fish populations and the revenues generated by the fisheries of the East and
South China Seas.

“Under certain climate change scenarios, seafood
species that are mainstays of the Hong Kong seafood market, such as groupers
and threadfin breams, could be reduced to a fraction of their present
population by the end of the century – if not driven completely to extinction,”
explained Dr. Rashid Sumaila, Professor at the Institute for the Oceans and
Fisheries and the School of Public Policy and Global Affairs at UBC.

“This is especially the case in the tropical
waters of the South China Sea, where many fish species are already facing the
limits of their heat tolerance,” he added.

The analysis specifically focuses on seafood
species that are valuable to Hong Kong, where 95% of seafood consumed is
imported and the annual value of imports rank amongst the highest in the world.

The severe climate change scenario estimated
losses in revenues upwards of US$10bn annually for South China Sea fisheries.
By comparison, US$3-7bn in losses are projected under a mild climate change
scenario, equating to 1˚C in global warming by mid-century.

Combined with the effects of a severe climate
change scenario, continued business-as-usual fishing intensity is expected to
result in a 90% drop in key commercial species, by weight (biomass) in the
South China Sea by the end of the century. This translates to a projected
US$11.5bn of annual revenue losses.

The East China Sea is similarly expected to lose
20% of the biomass of its key commercial species under this same set of
conditions. However, in a scenario where fishing intensity is reduced by 50% in
the next ten years and climate change is mild (i.e., 1˚C warming by
mid-century), the East China Sea has the potential to gain 20% in marine
fisheries biomass by 2100 compared to present day.

The overexploitation of Asia’s fisheries has in
part been driven by the growth of the aquaculture industry. Many commercial
vessels now opt for a ‘quantity over quality’ approach to produce feed for
farmed fish and animal feed – known as feed-grade fishing.

“Many people are unaware that aquaculture can
contribute to overfishing, rather than counteract it,” said Dr Yvonne Sadovy,
Honorary Professor at the University of Hong Kong. “By using wild-caught fish
for aquaculture feed, we are harvesting juvenile fish of commercially important
species and potentially jeopardizing future regional food security.”

The research highlights an urgent need to seek
alternative protein sources for the aquaculture industry. By allowing juveniles
to mature in the wild, modelling predicts that regional fisheries revenue would
be over ten times higher than if current feed-grade fishing practices are
continued.

“The research sets the foundation to initiate
regional dialogues to collectively manage East and South China fisheries,
especially including themes of climate change adaptation,” said Ashley Bang, an
author of the report.

“With a strong commitment to regional fisheries
management and climate change mitigation, our oceans can continue to support
Asia’s human, social, and economic well-being to infinity,” said Dr. Rashid Sumaila of UBC. “The choice is ours to
sink or swim.”

All eyes are on this week’s United Nations
Climate Change Conference (COP26) which will determine whether the necessary
actions will be taken to mitigate climate change. If not, the millions of
livelihoods that depend on the East and South China Sea’s fisheries will spiral
into crisis.

Read the full report here.