Tag Archives: river system

Cassini Spots Mini Nile River on Saturn Moon

PASADENA, Calif. – Scientists with NASA’s Cassini mission have spotted what appears to be a miniature, extraterrestrial likeness of Earth’s Nile River: a river valley on Saturn’s moon Titan that stretches more than 200 miles (400 kilometers) from its “headwaters” to a large sea. It is the first time images have revealed a river system this vast and in such high resolution anywhere other than Earth.

Scientists deduce that the river, which is in Titan’s north polar region, is filled with liquid hydrocarbons because it appears dark along its entire length in the high-resolution radar image, indicating a smooth surface. (more…)

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Earbones Accurately Record a Fish’s Life Travels

Studying the earbones of trout can reveal their lifetime movements in a large river system, according to a study released in the Canadian Journal of Fisheries and Aquatic Sciences.

Scientists correlated the natural variation in strontium isotopes found in stream waters against those recorded in otoliths (earbones) of westslope cutthroat trout to examine fish movements during their lifetime.

This study was the first to show that the use of isotopes in water and earbones accurately assesses movement of trout wholly within a freshwater system. The research was conducted by scientists from the U.S. Geological Survey’s Northern Rocky Mountain Science Center, Woods Hole Oceanographic Institution, Montana State University, and Montana Fish, Wildlife & Parks. (more…)

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Re-emergence of Salmon in The Thames ‘Not From Restocking’ Say Exeter Academics

*The recent returns of Atlantic salmon in the Thames are more likely to be a result of fish straying from nearby rivers rather than a consequence of expensive restocking efforts, according to new research by the University of Exeter.*

A team of University of Exeter bio-scientists, in collaboration with the Environment Agency, Westcountry Rivers Trust and Oviedo University, Spain, have been collecting genetic data from returning fish, which suggests that habitat restoration was more effective than re-introductions. The findings will be published in the journal ‘Biological Conservation’.

Lessons from the study could be applied to other rivers across the UK according to the co-author of the paper Dr Jamie Stevens, Associate Professor of Molecular Systematics at the University of Exeter. Dr Stevens says: “Traditionally, people – such as river owners and anglers – have wanted big fish swimming up their rivers. The easiest way to ensure this quickly has been to restock those rivers with exogenous fish (from outside the river system).” (more…)

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