Biologists determined that short-term, seasonal exposure to pesticides in rivers and basins may limit the growth and size of wild salmon populations. In addition to the widespread deterioration of salmon habitats, these findings suggest that exposure to commonly used pesticides may further inhibit the recovery of threatened or endangered populations.
"Major efforts are currently underway to restore Pacific salmon habitats in an effort to recover depressed populations," says David Baldwin of the National Oceanic and Atmospheric Administration (NOAA), who co-authored the study with NOAA colleagues in the December issue of the ESA journal Ecological Applications. "However, not much research has been done to determine the importance of pollution as a limiting factor of ESA-listed species."
The researchers studied the impact of pesticides, such as diazinon and malathion, on individual salmon using pre-existing data, and then devised a model to calculate the productivity and growth rate of the population. They used several exposure scenarios to reflect realistic pesticide use across various landscapes and over time.
Pesticides include insecticides, herbicides and fungicides that are usually applied to agricultural and urban landscapes. They primarily enter waterways in spray drift, surface runoff and irrigation return flows.
"An important aim of the work was to link known sublethal effects for individual salmon to impacts on the productivity of salmon populations," explains Baldwin.
The biologists found in previous studies that, on an individual level, the pesticides directly affected the activity of acetylcholinesterase, an important enzyme in the salmon brain. As a result, the salmon experienced reductions in feeding behavior. The reductions in food were then extended using the model to calculate reductions in the growth, size, and subsequent survival at ocean migration. In one scenario, the model predicted that, within a span of 20 years, returning spawners would have an increase of 68 percent abundance compared to a 523 percent projected increase in an unexposed chinook population.
"The model showed that a pesticide exposure lasting only four days can change the freshwater growth and, by extension, the subsequent survival of subyearling animals," says Baldwin. "In addition, the seasonal transport of pesticides to salmon habitats over successive years might slow the recovery of depressed populations."
The researchers argue that improving water quality conditions by reducing common pollutants could potentially increase the rate of recovery. Looking to the bigger picture, "This should help resource managers consider pesticides at the same biological scale as physical and biological stressors when prioritizing habitat restoration activities," says Baldwin.
Nadine Lymn | EurekAlert!
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Earth Sciences
05.12.2016 | Physics and Astronomy
05.12.2016 | Life Sciences