Tag Archives: fisheries

Pesticides linked to the collapse of fisheries in Japan

The recent collapse of two fisheries in Japan was found to be linked to the use of pesticides by nearby rice farmers, according to research, which warned similar impacts are likely to be found around the world.

A rice paddy in Japan. Credit Wikimedia Commons

The study, published in the journal Science, showed an immediate plunge in insect and plankton numbers in a large lake after the introduction of neonicotinoid pesticides to rice paddies. This was followed by the collapse of smelt and eel populations, which had been stable for decades but rely on the tiny creatures for food.

It was the first time a study revealed the effects of pesticides on fish. Previous studies in Europe have linked neonicotinoids to die-offs in other freshwater species including mayflies, dragonflies and snails and also to falling populations of farmland birds that feed on insects.

Prof Olaf Jensen, at Rutgers University in the US and not part of the research team, told The Guardian: “This study, although observational, presents compelling evidence. A fishery that was sustainable for decades collapsed within a year after farmers began using neonicotinoids. This is a large and astoundingly fast response.”

Researchers looked at data from Lake Shinji spanning the decade before and the period after the introduction of neonicotinoids in 1993, from which point the pesticides started running off into the lake. They found neonicotinoid concentrations in the water frequently exceeded levels that are toxic to aquatic invertebrates.

Amongst the worst affected, the midge Chironomus plumosus, an important food source for smelt, ranked the highest. It vanished completely from all 39 locations sampled in 2016, despite being abundant in 1982. Another important food source, an abundant zooplankton species, Sinocalanus tenellus, fell by 83%.

The study found annual catches of smelt fell 90% in the decade after neonicotinoids were introduced, compared with the decade before. Catches of eels dropped by 74% over the same time period.

“Several alternative explanations for the collapse were evaluated and rejected: invasive species, hypoxia, or changes in fish stocking cannot plausibly explain the observations,” said Jensen. Furthermore, catches of icefish, which do not rely on the affected invertebrates for food, remained unchanged.

The researchers noted that they also studied other factors that might have led to fishery collapses, such as nutrient depletion or changes in oxygen or salt concentrations. They report that they were not able to find any evidence showing that there might have been something other than pesticides killing the food fish ate leaving them to starve.


There is still hope: scientists show how fisheries can double production

The oceans are running out of fish. One third of fisheries have collapsed, meaning populations can not recover. Another third is being overfished, while only 29 percent of fish is currently caught sustainably. Forecasts suggest the situation is getting only worse. Given population increase, demand will jump so fisheries will become stressed further with no solution in sight. In reality, fisheries aren’t stressed by demand, but largely by perverse market incentives. A new research modeled thousands of fisheries from around the world and found that a straightforward economic reform will not only help fisheries recover in only ten years, but double production by 2050.


Image: Pixabay // Wikimedia Commons

Amanda Leland, senior vice president for oceans at the Environmental Defense Fund, along with colleagues wanted to see what would happen if the most successful fishery recovery story was replicated worldwide. Fifteen years ago, the West Coast fishery for groundfish, which includes rockfish and sole, hit a rock bottom low. That’s when the Environmental Defense Fund (EDF) decided to change the business model. Instead of limiting how much fish the industry is allowed to catch in an area, the norm set by most governments around the world, the regulators imposed strict  individual quotas that each fisherman can catch throughout the year.

Though it seems a subtle change, it made all the difference. Before this regulation was put in place, fishermen competed with each other for a limit common stock. Many would sail as early as possible, set their biggest fishing nets and try to catch as much as possible. Eventually, the market becomes flooded with fish — much more than the market demands. Prices are very low which means fishermen have to catch even more to make up in volume, and moreover a lot of fish goes to waste because it gets spoiled. Today, the West Coast groundfish can be caught sustainably and provide enough food to feed 17 million Americans for an entire year.

The “catch share” program from the West Coast was modeled for 4,713 fisheries across the world, the equivalent of 73% of the world’s entire catch. The first analysis confirmed what other studies previously reported: most fisheries are in a deprecated state due to overfishing, while only a third of all these fisheries are actually sustainable. Three scenarios were considered: business as usual; one where all fishermen are allowed to catch under a limit; one where each individual fishermen or crew is allowed to catch a specific percentage or fish within a certain designated area. It was only this latter scenario that made any economic sense. Projections suggest the median fishery takes only ten years to recover. Also, fishermen would experience a 204 percent surge in profits by 2050, the researchers report in PNAS.

“It would be very hard to find another global, significant environmental challenge that could be solved so quickly,” Leland told the Huff Post.

Under this reform 16 million more metric tones of fish would be caught and $53 billion more in generated revenue are expected compared to ‘business as usual’.

“This research shows that we really can have our fish and eat them too,” says Chris Costello, the paper’s lead author and a professor of environmental and resource economics at UCSB. “We no longer need to see ocean fisheries as a series of trade-offs. In fact, we show that we can have more fish in the water, more food on the plate, and more prosperous fishing communities—and it can happen relatively quickly.”

The findings are revealing. The West Coast success story is truly inspirational, and now we have evidence that this was not a fluke — it can be modeled all over the world. The ball is in the policymakers’ court now.