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181 posts in Publications

The curious tale of the piranhas that merely eat a few scales off their fish prey

Not all piranhas eat in the feeding frenzies that Hollywood is so fond of depicting. Instead, some species remove and eat just a few scales from their prey. As described in UW News, some of these scale-eaters ram into their unsuspecting prey, while others open their mouths to extraordinary dimensions and use specialized teeth to pry off scales. The wide variety of approaches is captured in a new paper that placed these fish in CT scanners, as part of the Scan All Fish program led by SAFS professor Adam Summers. 

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Forgotten fish naturalist and illustrator remembered in new book

Naturalist Charles Plumier’s work has been resurrected by SAFS Professor Ted Pietsch in a new book Charles Plumier and His Drawings of French Caribbean Fishes. Plumier lived in the era just before Linneaus created his Latin naming system for species names, and as a result, none of Plumier’s detailed painting and descriptions of species were given priority. Prof Pietsch talks in detail about the inspiration for his book with Michelle Ma in an interview posted on UW Today. 

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Costs of processing salmon limit the reward for managing predators and prey together

In Chignik, Alaska, sockeye salmon are preyed on when young by coho salmon; the sockeye support a valuable fishery, but coho do not. A simulation exercise examined whether fishers and processors might make more money if coho were reduced by fishing, under different levels of predation of coho on sockeye. Models suggested that fishers would end up with higher harvests, and make more money, but processors would probably not benefit because of the extra costs of processing low-value coho salmon.  

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Dam removal frees fish to feed in the ocean

Bull trout in the Elwha River have been separated from the ocean for a century, but dam removal in 2012-14 has now freed them to head out to the ocean again. Analysis of stable isotope ratios reveals that bull trout now spend substantial time at sea eating marine prey before heading back to the Elwha River to spawn. This re-emergence of a long-lost life history variation after being landlocked for so many decades, shows that fish species can swiftly adapt and change their strategies when new opportunities arise. 

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Revealed: the ups and downs of sablefish

Sablefish are a highly valuable commercial species that inhabit waters as deep as 750 m in the North-East Pacific. New pop-up satellite tag data now show that they do not stick to the bottom all the time: the majority of tagged fish migrate hundreds of meters up and down in the water column every day. The upward migration occurs at night and is likely because the sablefish are chasing their prey of fish, krill and squid, which are migrate vertically. 

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Salmon face the opposing forces of fishing selection and natural selection

A 100-year simulation of individuals reveals the opposing forces that fisheries and natural selection play in sockeye salmon in Bristol Bay, Alaska. Natural selection favored the production of longer salmon, but also produced differences between the body type of salmon spawning in shallow streams (where body depth declined) and those spawning in the beaches of large lakes (where body depth increased). 

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Major implications for aquaculture production from the fast-growing science of epigenetics

The expression of DNA can be changed not only by changing the sequence of DNA letters, but also through epigenetics, which involves heritable changes in gene expression, for example by adding methyl groups to parts of the DNA. A new review delves deep into the implications of epigenetics for both fish and shellfish aquaculture to identify key areas of aquaculture where epigenetics could be applied. 

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Identifying fish species using DNA barcodes from multiple areas of DNA

A new method for identifying species from their DNA expands on current “DNA barcoding” methods. In the current DNA barcoding methods, a particular promising section of DNA in the mitochondria of cells is sequenced, and differences in the DNA “letters” used to identify species with high accuracy: for instance, this method is more than 80% accurate for freshwater fish species in the Congo River basin. 

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Selecting the best methods to measure ecological impacts of marine renewable energy

The environment may be altered by marine renewable energy developments, which include offshore wind turbines, surface wave converters, and tidal turbines. To measure their impact, it is crucial to first study pre-development conditions, but indicators tracking these conditions may include variability that can be above and beyond the ability of standard models to characterize. In a new paper, the performance of 13 different types of models is tested, with three particular methods performing well under different conditions: vector regression, random forests, and state-space models. 

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Nearly 400 million people are at higher risk of schistosomiasis because dams stop prawn migration

River prawns eat the snails that harbor schistosomiasis (also known as snail fever or bilharzia), acting as a natural control on the disease. Schistosomiasis is a disease in humans caused by parasitic flatworms, which causes chronic pain and stunted growth, diarrhea, and bloody urine, and if left untreated, liver and kidney failure, infertility, and bladder cancer. The parasite infects river snails, which pass the parasites to humans when they come into contact with water containing the parasites. 

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