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96 posts in Research

Massive new map of genetic variation in rainbow trout and steelhead

Genetic techniques are capable of finding the entire sequence (“genome”) of DNA letters (“base pairs”), and have recently been applied to completely sequence 61 unrelated rainbow trout and steelhead individuals. The study found that one in every 64 letters varied across the rainbow trout examined (with variability in more than 30 million locations), and that there were more than 4 million locations where the individual DNA letters differ substantially. 

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Inherited growth rates and reproductive traits in oysters

Native oysters on the Pacific coast were devastated by commercial overfishing in the 20th century and their recovery has been prevented by water pollution, habitat loss, and possibly ocean acidification. Efforts underway to restore these Olympia oysters rely on harnessing genetic variation among populations to pick the best suited oysters for restoration. Now a new study shows that, even when reared for two generations under the same laboratory conditions, differences among populations persist. 

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Serious impacts of coal mining on stream dwellers

Coal mining is well known to have negative impacts on the quality of water in streams, and now new findings show that fish, invertebrates, and salamanders are badly affected by the resulting pollution. A synthesis demonstrated that animal numbers declined by more than half (53%), and species numbers declined by one third, in streams affected by coal mines. These impacts happened in spite of current federal statutes (the 1972 Clean Water Act and 1977 Surface Mining Control and Reclamation Act), and persisted even after cleanup efforts post-mining. 

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New tool for the safe passage of fish through hydroelectric dams

More than 80% of the world’s renewable electricity comes from hydropower generated from dams, but these dams impede upriver passage of fish, and potentially damage fish migrating downstream that pass through turbines or over slipways. A new toolset has now been developed that can better estimate injury and death rates from fish passing downstream, using the data from artificial “sensor fish” that mimic the passage of fish through turbines and slipways while collecting high-resolution data. 

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Timing of sea-ice retreat affects where birds are found

The Bering Sea has highly variable sea ice extent in winter, which can be used to tease out the effects of future climate change on marine animals such as seabirds. In a new study, SAFS professor George Hunt and coauthors examined how seabirds change location in years when sea ice melts earlier in the year. In these years, seabirds that feed far from land tend to come closer inshore, while seabirds that feed closer to shore move further offshore. 

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Massive death wave of sea birds was caused by a marine heat wave

A marine heat wave called The Warm Blob parked itself over the North Pacific Ocean in 2014-15, and has now been determined to be responsible for an unusually large mass mortality of Cassin’s Auklets. Volunteers involved in three citizen science projects (COASST, BeachWatch, BeachCOMBERS) scour beaches from California to British Columbia, and reported thousands of dead Cassin’s Auklets at the same time that the Blob was present. 

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Better measures of citizen science

Science can often benefit from broad participation in data collection by the public. For example, people recording their bird sightings in the eBird app has led to multiple scientific papers. Now a new paper provides valuable advice on how to set up and run such citizen science projects, including how to start a citizen science project, how to better collect data, and how to measure the impact of such projects. 

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Moving from single-species management to ecosystem management

Ecosystem-based fisheries management (EBFM) has become popular in recent years, but there is broad debate about what it means and how to implement it. At its simplest level, EBFM involves improving fisheries management by moving beyond management designed for single species, towards considering interactions that are important for entire ecosystems. Part if the reason this is difficult, says a new paper, is that perceptions of what counts as EBFM differ among stock assessment scientists, conservationists, ecologists, and managers. 

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Combining trawl and acoustic surveys to assess the status of the largest U.S. fishery

Many species of fish spend some of the time on the ocean bottom, and some of their time far off the bottom, which makes them hard to survey. Acoustic surveys (that bounce sound off fish schools), can estimate the midwater component of so-called “semipelagic” fish, while trawl surveys can measure the portion on the bottom. Now a new method has been developed that combines data from both types of surveys into a single estimate using information about the environment (bottom light, temperature, sand type, and fish size). 

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A whole new ocean zone is needed for these fish species

Scientists currently classify groups of reef species by the depths at which they occur, with the so-called “mesophotic” species living at depths of 40-150 meters. Now, though, new data suggests that an additional depth zone is needed for reef species living in the coral reef twilight zone, to be called the “rariphotic” zone, covering the depths of 130-310 meters (400-1000 ft). 

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