Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Contaminants linked to sturgeon decline in Columbia river

10.04.2006


White sturgeon populations in the Columbia River may be declining due to the presence of elevated amounts of foreign chemicals including DDT and polychlorinated biphenyls in their bodies, according to new studies by researchers at Oregon State University.



The research by Carl Schreck and Grant Feist, biologists in OSU’s College of Agricultural Sciences, has been published in the journals Environmental Health Perspectives and Archives of Environmental Contamination and Toxicology.

Their research shows that white sturgeon living in the Columbia River in some areas above Bonneville Dam have high amounts of toxic contaminants in their livers, sex organs and muscle tissue.


"We don’t know the exact source of contamination," Schreck said. "The fish move, the stuff they eat moves and the water and sediments bearing the contaminants moves. The Columbia receives input from numerous sources, so any population of fish at any one site can be exposed to a myriad of substances."

The OSU researchers say it is difficult to estimate the numbers of sturgeon in the Columbia, but there has been a noticeable decline in the number of young fish, indicating productivity is poor, especially in the impounded areas above dams.

In the past, any decreases in population were thought to be linked to the presence of dams, which have changed the temperature and flow of the river. And despite fish ladders in place for salmon, the bottom-dwelling white sturgeon rarely navigate dams successfully making it difficult for them to expand their habitat or access oceanic food sources.

Schreck and Feist studied white sturgeon from three reservoirs along the Columbia River and from areas downstream of Bonneville, the last dam on the river in its path to the Pacific Ocean. The researchers found some of the fish living in reservoirs behind the dams had concentrations of chemicals up to 20 times higher than the fish below Bonneville. The contamination was most significant in the reservoir behind the Bonneville Dam, the oldest dam on the river.

"We believe that some contaminants are accumulating behind the dams by settling out in the sediment as the water slows," Feist said, adding that at this point this is a hypothesis.

"Fish residing in the reservoir behind the oldest dam had the highest contaminant loads," Feist added, "and exhibited reduced growth and reproductive fitness when compared to fish sampled in other locations. These data suggest that some contaminants may be accumulating behind dams over time."

North America’s largest freshwater fish, white sturgeon can grow to 20 feet in length, weigh more than 1,500 pounds and live for more than a century. The fish have always been an important food source for Oregon’s Native Americans, and now as salmon runs diminish, white sturgeon fillets and steaks are increasingly sold in fish markets.

But because of their potentially high contaminant levels, Schreck cautions consumers to not eat the fish at every meal.

During the last 25 years, white sturgeon have experienced a sharp drop in population in the upper reaches of the Columbia River. In 1990, the Committee on the Status of Endangered Wildlife in Canada designated the white sturgeon as "vulnerable," only to reclassify it as "critically imperiled" in 1994.

Today, the fish, which are caught commercially and for sport on the lower Columbia, are listed as endangered in Canada. Fishing for white sturgeon is regulated by the state, with size limits precluding anglers from taking juvenile fish or large, older fish.

Carl Schreck | EurekAlert!
Further information:
http://www.oregonstate.edu

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>