Overfishing causing global catches to fall three times faster than estimated

Landmark new study that includes small-scale, subsistence and illegal fishing shows a strong decline in catches as more fisheries are exhausted
Damian Carrington The Guardian 19 Jan 16;

Global fish catches are falling three times faster than official UN figures suggest, according to a landmark new study, with overfishing to blame.

Seafood is the critical source of protein for more than 2.5 billion people, but over-exploitation is cutting the catch by more than 1m tonnes a year.

The official catch data, provided by nations to the UN’s Food and Agriculture Organisation (FAO), rarely includes small-scale, sport or illegal fishing and does not count fish discarded at sea. To provide a better estimate, more than 400 researchers around the world spent a decade finding other data to fill in the gaps.

The results, published in the journal Nature Communications, show the annual catches between 1950 and 2010 were much bigger than thought, but that the decline after the peak year of 1996 was much faster than official figures.

The FAO data indicated a catch of 86m tonnes in 1996, then a decline of 0.4m tonnes per year. In contrast, the new research estimates the peak catch was 130m tonnes, but declined at 1.2m tonnes per year afterwards.

“Our results differ very strongly from those of the FAO,” said Prof Daniel Pauly, at the University of British Columbia in Canada and who led the work. “Our results indicate that the decline is very strong and is not due to countries fishing less. It is due to countries having fished too much and having exhausted one fishery after another.”

Estimating subsistence, small-scale and illegal fishing is difficult, but Pauly said his team was confident in its results which - unlike the FAO data - includes estimates of the uncertainty. “This research is not based on a few studies here and there and then extrapolation,” he said. “It is based on the results of 200 studies we have conducted for about a decade by a network of 400 people in all countries of the world.”

The researchers used many different approaches to fill in the missing data, from hotel invoices for locally bought fish in the Bahamas to information on local fish consumption.

“This work has been carefully conducted by painstaking research into the hidden underbelly of global fishing, country by country, region by region” said Prof Boris Worm, at Dalhousie University in Canada and not involved in the new research. “This was a Herculean task that no one else has ever attempted. While the results necessarily remain uncertain, they undoubtedly represent our most complete picture yet of the global state of fish catches.”

Worm said the world’s fisheries were being over-exploited but that some stocks were being sustainably managed: “Where such measures have been taken, we find that both fish and fishermen are more likely to persist into the future.”

Global fish catches rose from the 1950s to 1996 as fishing fleets expanded and discovered new fish stocks to exploit. But after 1996, few undiscovered fisheries were left and catches started to decline. “It was never really sustainable,” said Pauly. The decline since 1996 has largely been in fish caught by industrial fleets and to a lesser extent a cut in the number of unwanted fish discarded at sea.

“The fact that we catch far more than we thought is, if you like, a more positive thing,” he said. “Because if we rebuild stocks, we can rebuild to more than we thought before.”

There has been success in some places where fishing has been restricted for a few years, for example in the Norwegian herring and cod fisheries. On resumption, catches were bigger than ever.

But Pauly said: “I expect a continued decline because I don’t expect countries to realise the need to rebuild stocks. I don’t see African countries, for example, rebuilding their stocks, or being allowed to by the foreign fleets that are working there, because the pressure to continue to fish is very strong. We know how to fix this problem but whether we do it or not depends on conditions that are difficult.”

Global fishing catch significantly under-reported, says study
Matt McGrath BBC 19 Jan 16;

The amount of fish taken from the world's oceans over the last 60 years has been underestimated by more than 50%, according to a new study.

Researchers say that official estimates are missing crucial data on small scale fisheries, illegal fishing and discarded by-catch.
The authors argue that global fishing catches are now declining rapidly because stocks have been exhausted.

But other researchers have questioned the reliability of the new study.

The UN's Food and Agriculture Organisation (FAO) is the body that collates global statistics on fishing from countries all over the world.

According to their official figures, the amount of fish caught has increased steadily since 1950 and peaked at 86 million tonnes in 1996 before declining slightly to around 77 million tonnes in 2010.

But researchers from the University of British Columbia argue that the official figures drastically under-report the true scale of fishing.

They argue that the figures submitted to the FAO are mainly from large scale "industrial" fishing activities and do not include small scale commercial fisheries, subsistence fisheries as well as the discarded by-catch and estimates for illegal fishing.

The scientists say their "catch reconstruction" method give a far more accurate picture of the scale of the impacts of fishing around the world.

They say that reconstructed catches, that include estimates and data on the under-reported activities, show that the world took 53% more fish from the seas than the official figures indicate.

They argue that around 32 million tonnes of fish go unreported every year - more than the weight of the entire US population.

"The catches are all underestimated," said lead author Prof Daniel Pauly.

"The FAO doesn't have a mandate to correct the data that they get - and the countries have the bad habit of reporting only what they see - if they don't have people who report on a given fishery then nothing is reported. The result of this is a systematic underestimation of the catch and this can be very high, 200-300% especially in small island states, in the developed world it can be 20-30%."

Prof Pauly gave the Bahamas as an example where there was no reporting of fish caught by small scale fishers. But when the researchers dug a little deeper and went to the big hotels and resorts, they found invoices from small scale fishermen who sold their catch directly.

Not only have more fish been taken from the seas than have been reported say the authors, but the decline in fish caught since the mid 1990s has been far greater than the official figures show.

The researchers say this isn't because the world is doing less fishing, it's because over exploitation means there are simply less fish being caught.

"It was never really sustainable," said Prof Pauly.

"We went through one stock after the other, for example around the British Isles, the stocks in the North Sea were diminished right after the Second World War.

"And then British trawlers went to Iceland and did the same thing there, and so on and so did the Germans, the Americans, so did the Soviets.

"They had to expand to survive and now the fisheries are in Antarctica."

While other scientists in this field have praised the comprehensive nature of the study, some have criticised the methods used.

"I think we all agree that global catches are probably higher than reported but I do not think that this new catch reconstruction is sufficiently reliable to draw conclusions concerning trends in catches or global fisheries," said Dr Keith Brander, an expert of on fisheries and marine ecosystems who is now an emeritus scientist at the Technical University of Denmark.

"It may point to particular regions and fisheries sectors that require substantial improvement in statistics in order to improve fisheries management, but to do this one really needs to get into the fine detail," he told BBC News.

The authors say that they have every confidence in their work. They say they are not based on a handful of studies but on around 200 research papers conducted over a decade by a network of 400 scientists based all over the world.

While praising the "huge and impressive amount of work" that went into the study, Prof Trevor Branch from the University of Washington said that the report raises another important question that still remains unanswered.

"Catches only tell us what we take out, not what the status of the remaining fish is," he said.

"So it's like trying to measure deforestation from counts of trucks of lumber driving away from forests."

The study has been published in the journal, Nature Communications.

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