Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Notre Dame research reveals migrating Great Lakes salmon carry contaminants upstream

07.12.2012
Be careful what you eat, says University of Notre Dame stream ecologist Gary Lamberti.

If you're catching and eating fish from a Lake Michigan tributary with a strong salmon run, the stream fish — brook trout, brown trout, panfish — may be contaminated by pollutants carried in by the salmon.

Research by Lamberti, professor and chair of biology, and his laboratory has revealed that salmon, as they travel upstream to spawn and die, carry industrial pollutants into Great Lakes streams and tributaries. The research was recently published in the journal Environmental Science and Technology.

It's a problem inadvertently created by people with good intentions, he notes.

"Most people don't realize that salmon are a non-native species in the Great Lakes," he says. "They were introduced to control alewives — another non-native fish species."

Although salmon fed on and contained the alewives — and have become important to sport fishing—there were unintended consequences. That's because of a lengthy history of industrial pollution of the Great Lakes.

"All the Great Lakes have some level of pollution," says Lamberti, "especially near cities — Chicago, Detroit, Cleveland. There are far fewer pollutants now than over the past century, but many are persistent. There are hot spots, and Lake Michigan has a lot of them — heavy metals, mercury, organic pollutants like PCBs."

PCBs (polychlorinated biphenyls) come from fluids in older electrical transformers. Also present is DDE (dichlorodiphenyldichloroethylene), a breakdown product of the banned insecticide DDT, and PBDEs (polybrominated diphenyl ethers). PBDEs, notes Lamberti, are flame retardants used in furniture, mattresses and children's clothing. "They wash out when you do the laundry."

Brook trout with salmon eggs pumped from its stomach Brook trout with salmon eggs pumped from its stomach

Even intentionally introduced species such as the Pacific salmon can result in unintended consequences for the ecosystem and the environment.

Salmon acquire pollutants through the lake food chain. When they are young, they feed on invertebrates — worms and insect larvae. As they grow larger, salmon consume more and more fish, such as alewives — which have also picked up pollutants through invertebrates they eat, which have picked up pollutants from algae and bacteria.

Salmon are a fatty fish, and these polluting chemicals are particularly "sticky," Lamberti says. "They are lipophilic — they absorb into fat tissue."

The consequence is that the salmon magnify the pollutants as they move up the food chain. "Salmon are longer lived, eat more, and the pollutants are then bio-concentrated."

The concern is that salmon are naturalized to many tributaries of the Great Lakes. "And it's a one-way street for them," Lamberti says. "They spawn, die in the stream where they spawn, and then leave their contaminant load in the stream. Stream fish eat salmon eggs, and may also eat carcass tissue as they decompose."

Fish in streams and tributaries with large salmon runs — fish that never go out into the lake, he notes — show contaminant levels very similar to that of Great Lakes salmon.

"Let's keep in mind," he adds, "there are FDA advisories for pregnant women and children on the risks of eating large Great Lakes fish, because of the danger of chemical contaminants.

"But there are no warnings for stream fish — that's the specter. If you're eating fish from a stream with a lot of salmon, you might as well be eating the salmon. I would err on the side of caution when eating any fish from a salmon river. Either that or harvest fish only upstream of where salmon spawn."

For comparison purposes, Lamberti's research analyzed the tissue of fish upstream from where salmon spawn and die.

"The upstream section of the same river was not contaminated. Below the salmon, the river had measurable levels of contaminants. There's no other way for the contaminants to get there but the salmon. Water doesn't flow uphill."

The conclusion?

Although salmon are an economic benefit to the Great Lakes and perform important ecological functions (such as controlling the population of alewives), we need to consider the impact of salmon on streams where they spawn.

"If we want to remove a dam on a river — and that will allow salmon to move upstream — we need to realize that the salmon will carry pollutants with them and disperse them into the food web," Lamberti says.

"In sensitive areas with a lot of native fish, we might want to prevent salmon from moving upstream. And in the Great Lakes, maybe we should consider restoring the native populations of lake trout and whitefish rather than encouraging more salmon."

Gary Lamberti | EurekAlert!
Further information:
http://www.nd.edu

More articles from Ecology, The Environment and Conservation:

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

nachricht Species Richness – a false friend? Scientists want to improve biodiversity assessments
01.08.2017 | Carl von Ossietzky-Universität Oldenburg

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>