Freshwater fish with bellies full of shrews – one trout a few years back was found to have eaten 19 – aren’t as random as scientists have thought.
In some years, probably when shrew populations boom, the small mouse-like land animals end up in the stomachs of a quarter of rainbow trout and Arctic grayling larger than a foot, according to University of Washington-led research in the coastal lakes and streams of Southwest Alaska. (more…)
Even as the dinosaurs were becoming extinct 66 million years ago, the ancient ancestor of spiny-rayed fishes flourished, eventually giving rise to tens of thousands of species that can now be found in home aquariums or on dinner plates. Using modern genetic tools and information from the fossil record, a team led by researchers at Yale University, University of Oxford, and University of California-Davis have constructed a detailed evolutionary history of the 18,000 species of spiny-rayed fishes existing today, a diverse group that includes basses, pufferfishes, and cichlids, and that comprises a large portion of the vertebrate tree of life.
The findings published the week of July 15 in the Proceedings of the National Academy of Sciences show surprisingly close evolutionary relationships between lineages of fish species such as tunas and seahorses, and suggest some fish lineages — like cichlids, the tiny gobies, and little-studied snailfishes — are experiencing high rates of new species origination. (more…)
Imagine having a daylong Thanksgiving feast every day for a month, then, only pauper’s rations the rest of the year.
University of Washington researchers have discovered Dolly Varden, a kind of trout, eating just that way in Alaska’s Chignik Lake watershed.
Organs such as the stomach and intestines in the Dolly Varden doubled to quadrupled in size when eggs from spawning sockeye salmon became available each August, the researchers found. They were like vacuums sucking up the eggs and nipping at the flesh of spawned-out salmon carcasses. (more…)
When it comes to evolution, humans can learn a thing or two from primeval sea lampreys.
In the current issue of Nature Genetics, a team of scientists has presented an assembly of the sea lamprey genome – the first time the entire sequence has been decoded. The data is compelling as the sea lamprey is one of the few ancient, jawless species that has survived through the modern era.
The paper not only sheds light on how the venerable invasive species adapted and thrived, but it also provides many insights into the evolution of all vertebrates, species with backbones and spinal cords, which includes humans, said Weiming Li, Michigan State University fisheries and wildlife professor, who organized and coordinated the team. (more…)
A new study led by the University of Colorado Boulder indicates air pollution in the form of nitrogen compounds emanating from power plants, automobiles and agriculture is changing the alpine vegetation in Rocky Mountain National Park.
The emissions of nitrogen compounds to the atmosphere are being carried to remote areas of the park, altering sensitive ecosystems, said CU-Boulder Professor William Bowman, who directs CU-Boulder’s Mountain Research Station west of Boulder and who led the study. “The changes are subtle, but important,” he said. “They represent a first step in a series of changes which may be relatively irreversible.”
In other regions of the world, higher amounts of nitrogen pollutants correlate with decreased biodiversity, acidified soils and dead stream organisms like trout, said Bowman. “There is evidence that indicates once these changes occur, they can be difficult if not impossible to reverse. It is best to recognize these early stages before the more harmful later stages happen.” (more…)
