Fish Harvest Down 90% After Pesticide Use

Analysis by Dr. Joseph Mercola Fact Checked

fish population decline

Story at-a-glance -

  • Research data show an association between the 90% reduction of fish harvested from Lake Shinji and the application of neonicotinoids to adjacent rice paddies
  • The researchers quoted the same prediction made by Rachel Carson in her 1962 book “Silent Spring”
  • Neonicotinoids have drastically reduced the insect population; this loss will have a cascading effect on food ecosystems, the ramifications of which should not be taken lightly
  • Neonicotinoids come with high risk, but little reward as evidence shows monocrop fields using them have a greater damaging insect population than regenerative farms

A fishery is an organized means of catching fish, an activity otherwise known as fishing. This is different from fish farms, also known as aquaculture. On fish farms, the fish are commercially raised in enclosures for food, while a fishery is organized fishing for wild fish.

Farmed fish are some of the most toxic foods; this is especially true for farmed salmon, according to one study. Researchers found that farmed salmon tested five times more toxic than other food products. Farmed salmon contain half the omega-3 of wild salmon and are often fed a genetically modified diet. Many are given antibiotics and exposed to pesticides and other toxins to offset the unsanitary conditions in which they live.

Although farmed fish are exposed to purposely applied pesticides, fisheries in Japan have experienced a significant decline in fish and eel populations after neonicotinoids were sprayed in adjacent fields. Also known as neonics, this is a relatively new classification of insecticide that is water soluble and operates systemically.

This means the plants absorb the pesticide. The toxin in neonics operates on the central nervous system of the insects, causing death or impairing the ability to forage in pollinators. The idea was to create a defense mechanism for the plant so insects feeding on them would die before they did significant damage to the crops.

Fish Starved When Their Food Source Affected by Neonics

This widely used type of pesticide has now been associated with a declining harvest from Lake Shinji in Japan. Once a thriving fishery, researchers have found annual catches of smelt have fallen by 90% in the 10 years after the introduction of the pesticide to the surrounding fields.1

The study,2 published in Science, showed there was an immediate decline in the number of insects and plankton in the lake after neonics were used in adjoining rice paddies. This was rapidly followed by a collapse of the smelt and eel populations that rely on the insects and plankton for food.

The populations of smelt and eel had been stable for several decades, and while the analysis shows a strong correlation, the study was not designed to prove a causal link.

Damage to pollinators by neonics has been well-documented. The die-off to freshwater species has been studied more heavily in Europe, where data have linked the toxin to a collapse in the population of dragonflies, snails and mayflies associated with a decline in populations of birds feeding on those insects.

Other groups were recording the salt and pollution content in the lake, but the scientists didn't believe the reduction in the fish population was coinciding with those results. Masumi Yamamuro is a scientist with the Geological Survey of Japan and lead author on the study who investigated the cause of the decimation to the fish population.3

The researchers noticed one fish population had not declined and they determined the species had a more diverse diet and could survive on algae, not affected by insecticides. As the food sources for smelt and eel food were vanishing, the fish were dying as well.

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One Chemical Has a Complicated Effect on the Ecosystem

Purdue University ecologist Jason Hoverman, who was not involved in the study, commented on the interrelationship of ecosystems often overlooked by agrochemical companies and big business. He said to NPR reporter Dan Charles:4

"When we think about chemicals, we often just go right to direct toxicity, not thinking about the food web implications; the food of the fish, and the impact of the chemicals on that food."

In 1962, Rachel Carson predicted the decline of the insect population, which she foretold would touch every living ecosystem on the earth. She was a celebrated biologist, ecologist and writer who called for responsible action to steward the Earth's resources.

She warned the federal government was part of the problem that could lead to environmental failure. Events predicted in her book have since come to pass in the last few decades. The Japanese researchers quoted Carson's "Silent Spring":5

"She wrote: 'These sprays, dusts and aerosols are now applied almost universally to farms, gardens, forests and homes — nonselective chemicals that have the power to kill every insect, the 'good' and the 'bad', to still the song of birds and the leaping of fish in the streams.' The ecological and economic impact of neonicotinoids on the inland waters of Japan confirms Carson's prophecy."

Matt Shardlow6 is a conservationist, author and CEO of Buglife, the only organization in Europe dedicated to saving invertebrates. The organization works to save bug habitats from destruction and to improve freshwater ecosystems. He commented to the Guardian on the results of this study:7

"Japan has had a tragic experience with nerve-agent insecticides. In the paddy fields, where the air once thrummed with the clatter of billions of dragonfly wings, these insecticides have imposed near silence. The annihilation of humble flies and the knock on effects on fish serve as further testament to the dreadful folly of neonicotinoids.

It is also extremely worrying that the levels of neonicotinoids in rivers in eastern England, as recently reported by Buglife, are very similar to the levels reported in this research. Unfortunately, while it is clear that harm must have been done to UK river health, the exact impact of neonicotinoids has yet to be quantified."

Vanishing Insect Population Affects Human Food Supply

In speaking with NPR Hoverman raised more specific questions about the cause of the problems:8

"These chemicals can definitely end up in water. We apply them on land, but they don't stay on land. The question becomes, are they at levels that are high enough to cause a problem?"

Other scientists studying the effects have acknowledged how these killer chemicals have damaged the environment, both immediately after application and years later. Yamamuro writes in the study,9 "This disruption likely also occurs elsewhere, as neonicotinoids are currently the most widely used class of insecticides globally."

If you remember going on a road trip as a child, you likely have a memory of bugs being smashed on your windshield. If you think about it for a minute, you may realize it's been awhile since your windshield was covered with insects. This has been called the "windshield phenomenon" by entomologists and is an ominous warning of the decline in insect species.

In one study evaluating the total flying insect biomass over 27 years in 63 protected areas in Germany, researchers discovered there had been a 76% decline. These reductions happened regardless of the type of habitat and were not explained solely by changes in weather, land use or habitat characteristics.

The researchers cautioned the loss of diversity and abundance could provoke a cascading effect on food ecosystems and the ramifications should not be taken lightly. Experts estimate 80% of wild plants depend on insects for pollination, 60% of birds depend on them for food and ecosystem services in the U.S. estimate their worth at $57 billion annually.

A study by researchers from the University of Nevada followed 67 butterfly species over 20 years in four locations. They discovered a significant reduction in the butterfly population was closely linked to the increased use of neonicotinoids.

Neonics Have High Risk and Little Reward

One study found agricultural lands in the U.S. are now 48 times more toxic than they were a short 25 years ago. The researchers found synthetic insecticide use shifted from organophosphorus pesticide to a mix of neonicotinoids and pyrethroids. The number of crops treated with neonicotinoids has risen precipitously and seed suppliers have doubled the amount of insecticide applied to each seed.

In the 1990s, only 35% of U.S. corn and 5% of soybean acres were treated with neonicotinoids. At that level of application, the pest population was not damaging enough to crops to cause economic harm, suggesting that treating hundreds of millions of acres is not necessary.

Despite years of evidence that neonics have a damaging effect on the environment with long-term damage on humanity, the use of this class of insecticide has continued. To compound the problem, farmers are not experiencing great benefits from the practice.

The investigators of one study compared results of farmers using regenerative practices to those who were using current monoculture methods. They discovered regenerative fields had a 29% lower production, but a 78% higher profit. In their review of pest management, they found corn fields treated with insecticides had 10 times more pests than those of regenerative farms.

Reduce Pesticide Use and Support Regenerative Farms

One key to reducing damage to the environment, wildlife and ultimately human health is to reduce the use of pesticides. Although the application is so commonplace it may seem necessary, researchers have demonstrated that pesticides can be cut without harming yields.

The results from some studies suggest reducing pesticide use may reduce crop losses since neonic coated seeds injure useful insects that help kill other pests naturally. Ecologically-based farming practices to help kill soybean aphids could save farmers in four states from hundreds of millions in losses each year.

Despite these findings, farmers are inundated with neonic-treated seeds and have limited ability to avoid them. Regenerative farming improves the biodiversity of the soil. It does not harm the environment and it ultimately increases the farmers' net profits, allowing them to continue providing food for the world and supporting their families.

Regenerative practices rebuild the topsoil, protect water sources, protect the insect population and offer you optimal nutrition. If you're not able to grow your own food, choose fresh, organic produce from local growers and seek out farmers who provide organic, grass fed beef, poultry and dairy products.

Certifications indicating farmers are using regenerative principles include Demeter biodynamic certification and American Grassfed Association (AGA) certification.