A Fishy Study Posits That Pesticides Can Travel Back In Time


It’s not surprising that many people are skeptical about “scientific” findings. A new study from Japan seems to show that neonicotinoid insecticides (“neonics”), used around the world to protect crops from insect infestations, are so destructive that even before they were on the market or ever used in farmers’ fields, they were able to cause entire ecosystems to collapse. Sort of like “Back to the Future” meets “Jurassic Park.”

At least that’s what one must assume after reading the research article, which like others purporting to show harmful environmental effects of neonics, got extensive and often sensationalistic coverage in the media. “Fishery collapse ‘confirms Silent Spring pesticide prophecy,’” trumpeted the Guardian. National Geographic headlined, “How the world’s most widely used insecticide led to fishery collapse,” with the sub-headline alerting readers that the same thing is likely happening to aquatic ecosystems “worldwide.”

In other words, OMG!


This is, of course, only the latest apocalypse being ascribed to neonics. As I’ve detailed in Part 1 and Part 2 of this series, the ongoing, relentless campaign by environmentalists and activist scientists against these insecticides highlights what I have dubbed the Pseudo-Science Method (PSM). Drawing its inspiration more from Saul Alinsky, the author of “Rules for Radicals,” rather than Roger Bacon or Galileo, the PSM first picks an enemy — in this case a popular, state-of-the-art insecticide — then manufactures the evidence needed to condemn it.

During the years I’ve been writing about neonics, we’ve gone through a litany of supposed neonic-caused catastrophes that were widely and sensationally reported in the press, only to be revealed a short time later to be either wholly fictitious or in no demonstrable way connected to neonics.

The first was the infamous “bee-pocalypse,” the supposedly imminent extinction of the world’s honeybee population, which led to a complete ban on neonics in the European Union. As we all know now, the claims of plummeting honeybee populations had simply been fabricated by anti-pesticide activists. Their numbers have been rising on every habitable continent in the world since neonics came on the market in the mid-1990s.

Without missing a beat, the warnings of apocalypse shifted to a purported collapse of “wild bees.” This, too, turned out to be a fiction. The biggest problem with this narrative is that those wild bee species that come into most contact with agricultural crops, and thus neonics, are thriving; and, as the foremost wild bee specialist in the country, Sam Droege of the U.S. Geological Survey, has said, there simply is no evidence of widespread collapse of wild bee populations. In his words, wild bees are doing fine.

The third supposed apocalypse sprang into the headlines less than a year ago, with the publication of the claim by longtime neonic-antagonist Francisco Sanchez-Bayo that the entire insect world was going extinct. (OMG, again!) But the study was so obviously contrived to produce a scaremongering, invalid result that it was widely panned by other scientists. Even the environmentalist-loving BBC tore it to pieces. Science writer Matt Ridley and investigative reporter Jon Entine revealed the study authors’ penchant for simply fabricating evidence when the facts didn’t support their case.

In the apocalypse cavalcade, after the bees and other insects came the birds. Strangely, the “bird-pocalypse” almost exactly replicated the supposed honeybee-pocalypse in the United States: real population declines after World War II leveled off and began to reverse in the mid-1990s, just as neonics were coming on the market. (See the figure below.)

Fish Gotta Swim, Birds Gotta Fly, Activist Researchers Gotta Lie

All of which brings us to the latest innovation in the neonic-apocalypse playbook, the study by Japanese researchers who looked at the collapse of fish populations (actually, only some fish populations) in Lake Shinji near the coast of western Japan. Using the date 1993 as their reference point because that was the year neonics were first used by Japanese rice farmers, they showed that yields of smelt and eel, which were abundant in the 1980s, have declined to near zero in the case of smelt, while eel remain considerably below earlier levels, in spite of yearly restocking of the lake with eggs.

The researchers, led by Masumi Yamamuro of the Institute of Geology and Geoinformation in Japan, hypothesize that these declines are due to neonics carried into the lake from nearby rice fields; as a mechanism, they blame declines in “zooplankton biomass” — the invertebrate species of insects and crustaceans that comprise much of the fishes’ diet.

At first glance, figures 1 and 2 — reproduced here as they appear in the published study — seem persuasive. In the top graph we see neonic quantities rising with time, while, in the bottom graph, zooplankton biomass dramatically collapses.

Neonics: The Wonder Of Time Travel

However, there’s a problem with that interpretation. On closer examination, it is evident that the dates in horizontal axes of the two figures are not aligned, and if you center both graphs on 1993, the first year neonics were used (below), it becomes clear that zooplankton biomass had been in precipitous decline for at least a decade before neonics were introduced on rice farms.

In other words, the bottoming out of zooplankton in 1993 — the year that neonics were first used by Japanese rice farmers — is clearly the culmination of a trend, a steep and persistent decline that had been going on for more than a decade and very likely much longer. The fact that the use of neonics in 1993 overlaps for one year with the very tail end of this trend can hardly be said to represent a genuine correlation, especially given that for the first six years of neonic usage, 1993-1998, negligible quantities of neonics were used.

To state the obvious, neonics can’t be blamed for trends that started long before they were ever applied to farmers’ fields. But if one looks for the authors to provide an explanation of what was causing the rapid decline in the preceding years, one looks in vain.

The supposed correlation becomes even less convincing given that figure 1 doesn’t even represent actual measurements of neonic levels in Lake Shinji. The only actual measurements of neonic levels in the lake water were taken by the authors in a single year, 2018, a quarter century after the 1993 reference year. In fact, the authors have no idea about neonic levels in the lake prior to 2018. They are asking us to accept instead, as a kind a proxy for actual measurements, the total sales volume of neonics in the entire Shimane Prefecture, in which Lake Shinji is located.

Something is obviously very fishy here, and one has to wonder not only about the competence of the investigators but whether the peer reviewers were comatose, in overlooking these points.

A Dose Of Skepticism

Next, we get to the critical issue of dose-response — in this case, neonic levels in the water. The authors took several measurements in three different sampling sites in the lake, from April through June 2018. In the published study itself, the authors report only one finding, the highest and only significant concentration found, which was a total that added up all the neonics together. This came to 0.072 ug/l, which is 72 parts per trillion.

The precision with which this is reported is a bit dubious, given that in the Supplemental Materials they acknowledge the Limit of Quantification (the level below which it is not possible to accurately measure a quantity) is 0.1 ug/l for one neonic (thiamethoxam) and 0.2 ug/l for two others (clothianidin and imidacloprid). (This is another point that should have concerned the peer reviewers.)

Even if we accept the authors’ measurements, neonic levels did not rise high enough to do the ecological harms posited by the authors. This is even more true for crustaceans which, according to the authors, form a large part of the zooplankton biomass and are a critical part of the fish diet. As reported in a 2018 study by Raby et al, crustaceans are generally much less sensitive to neonics than are the insect species on which the benchmarks are based.

Things look even worse for the study if one applies the researchers’ surrogate measurement (neonic sales) consistently. Extrapolating back from 2016, when sales were about 4,000 kilograms an acre, to the first six years neonics were on the market, when sales appear to have been well below 200 kilograms per acre, neonic levels back then were at least 20 times below what the study measured in 2018. In other words, the highest measurement, 0.074 ug/l, would become 0.0037 ug/l, an order of magnitude or more too low to do any harm even to the most sensitive insect species.

Other Possible Causes of Decline of Zooplankton

Given the obvious chronology problems in attributing fish declines to neonics, it would have made sense for the authors to look for other possible causes. As it turns out, they aren’t hard to find. According to the World Lake Database, for instance, since 1966 the shoreline of Lake Shinji has experienced major industrial development that has resulted in significant pollution of the lake’s waters.

A 2011 study of chemical contaminants in Lake Shinji found that “lake sediments are moderately to strongly polluted with respect to As [arsenic], moderately polluted with Pb [lead] , Zn [zinc], and Cr [chromium].” Other researchers (Hook and Fisher 2001; 2002) looking at the effects of zinc and other chemical pollutants on copepods (small crustaceans like those that make up a good deal of the zooplankton food supply for fish in Lake Shinji) found exposure to these metals led “to sublethal effects (e.g., decreased egg production and hatching, ovarian development, and protein concentration in eggs) at concentrations 2~3 orders of magnitude less than lethal concentrations.”

Yamamuro et al also neglect to mention that the lake suffers major, long-standing problems with eutrophication (oxygen-depleted water). Japan’s Ministry of the Environment notes succinctly about Lake Shinji: “Deterioration of water quality by socio-economic activities in catchment area. Eutrophication with water bloom in summer.”

Eutrophication is generally caused by excessive nutrients from sewage, fertilizer and other organic and inorganic pollutants which are carried into the lakes, resulting in explosive algae growth, the buildup of hydrogen sulfide, and oxygen depleted (hypoxic) water. While the researchers say that oxygen and some other measurements in Lake Shingi were similar before and after 1993, the effects of eutrophication on lake ecology are highly complex, can manifest over long time periods, and even to this day are not fully understood. This is a fact that the study’s lead researcher Yamamuro acknowledged repeatedly in an earlier study of Lake Shinji and Lake Nakaumi:

The decrease of the bottom-dwelling fish, however, might result from increased eutrophication. … The increase in plantivorous species, K. punctatus and S. zunasi, also might be related to an increase in phytoplankton, although relationships in the lake’s food web are not clarified. [Emphasis added]

An earlier study by Yamamuro attributed the loss of fish in Shinji to the loss of “spawning and nursery areas, because 75% of the natural coast of the lake has changed with the construction of an artificial wall (Environmental Agency, 1993) during the course of urbanization of the area.”

Perhaps it’s not a coincidence that this wall appears to have been built around 1993, the authors’ pivotal date in this new study when, they claim, the lake’s environmental collapse began.

Do Science Journalists Know How To Google?

And just as the media never bothered to google “honeybee populations” before writing thousands of inflammatory headlines about the “bee-pocalypse,” apparently, they failed to Google Lake Shinji, as well. It appears that despite massive eutrophication, chemical pollution from 50 years of industrial development, among other things, Lake Shinji is doing pretty well, thank you. Japan’s Ministry of the Environment extols the lake’s “Rich Biodiversity” thusly:

Shinji-ko offers an essential habitat for approximately 80 brackish water species of fish and shellfish, including Japan’s endemic Shinji-ko Goby, Japanese Seaperch, Eel, Icefish and Corbicula Clam. Shinjiko is blessed with the largest catch of Corbicula Clams in Japan. Shinji-ko is also home to 200 species of migratory birds.

So much for the Yamamuro et al study, perhaps the worst and most irresponsible article I have encountered during more than 40 years of reading Science. And so much for the fish-pocalypse.

Henry Miller, a physician and molecular biologist, is a senior fellow at the Pacific Research Institute. A 15-year veteran of the FDA, he was the founding director of the agency’s Office of Biotechnology. Please follow him on Twitter at @henryimiller.

Nothing contained in this blog is to be construed as necessarily reflecting the views of the Pacific Research Institute or as an attempt to thwart or aid the passage of any legislation.

Scroll to Top