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210 posts in Research

New miniaturized acoustic fish tag is small enough to be injected by a syringe

Smaller tags are needed to eliminate tagging effects in fish survival studies. Now a new miniaturized acoustic tag is small enough to be injected by syringe. The injectable transmitter, engineered by Pacific Northwest National Laboratory, is just 15 mm in length, 3.35 mm in diameter, and weighs 0.216 g. The research team tested the new tag over a 500-km reach in the Columbia/Snake River using young Chinook salmon. 

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Genetic technique discovers three hidden species where one was assumed

Redfish (North Atlantic fish in the genus Sebastes) are highly diverse and notoriously hard to identify. Now, new research shows that the problem is even worse than was thought. The new genetic analysis of microsatellites in rose fish (Sebastes norvegicus) showed that what is currently thought to be a single species, is actually three separate species. One of the new species, the giant version, is larger and has some biological features that can be used to distinguish it; but the other two new species are currently impossible to distinguish by external appearance. 

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Old growth fishes become scarce under fishing

New research shows that the oldest fish can decline dramatically in fished populations, even when fisheries are sustainable. Old fish declined in 97% of populations when compared to an unfished state, and in about a third of populations, old fish declined by more than 90%. These changes reduce the diversity of fished populations, which can lead to lower stability. Reducing the impact of fishing on old fish would require marine reserves, rotational harvesting, or slot limits that prohibit fishing on all but a narrow range of fish ages. 

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Infectious diseases decline with urbanization and wealth, but not biodiversity

Infectious diseases reduce human health both through death and disability, with the total disease burden being lower in wealthy and more urban countries, but higher in countries with more biodiversity. Contrary to expectations, increases in biodiversity over time did not result in better human health, and in fact higher disease burdens resulted when forest cover increased over time. Thus the key reason why infectious disease burdens have declined in recent decades is a shift towards urbanization and greater wealth, immediately suggesting levers for improving global human health. 

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Fishing portfolios and shifts buffer Alaskan communities from abrupt change

New research on Alaskan fishing communities shows the crucial importance of fishing portfolios and turnover. In 1989, when there were both major ocean and market regime shifts, most communities lost fishing revenue. But those with the greatest diversity of fished species, and those that were most able to switch from one group of species to another, had little lost revenue, or even experienced increased revenue. 

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When do multiple factors act together to endanger animal populations?

Animal populations are endangered when they face multiple human-caused pressures at the same time, especially if those pressures interact to worsen depletion. A new study shows that whether pressures interact to worsen overall pressure, or interact to reduce overall pressure, depends on how animal populations behave at low versus high densities. If the number of offspring that survive for each adult drops off slowly as populations increase, this can unexpectedly lead to trouble, since it is more likely that individual pressures will interact to make things worse. 

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SAFS professors Parrish and Roberts highlighted for their open science work

To celebrate International Open Access Week, the University of Washington Libraries posted profiles and interviews with two SAFS faculty, Julia Parrish and Steven Roberts, about how they conduct their research openly. The interview with Julia Parrish focuses on her citizen science work, which involves trained members of the public identifying and pinpointing the locations of more than 10,000 dead birds on the Pacific coast each year, and making the data available openly as well as in scientific publications. 

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New advice on how to better estimate maximum sustainable yield for fisheries

A major component of fisheries management is using highly complex computer models to figure out the highest catch that can be taken from a fish population—the so-called Maximum Sustainable Yield, or MSY. A critical assumption underlying MSY estimates is how to model the relation between total amount of spawning fish and the resulting offspring that they produce. A new paper by SAFS director André Punt and NOAA researcher Jason Cope examines a wide range of these models to find the best three-parameter version that can independently estimate both the amount of spawning fish and the fishing harvest rate that will produce MSY, concluding that the Ricker-Power model is the best. 

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The power of entire DNA sequences to secure the future of seafood

A new review of the contribution of genomics to seafood management reveals how new questions may be addressed by genetics. Genomics involves sequencing the complete DNA of organisms, which has a great variety of applications, including greatly enhancing our ability to define management units, tracing whether seafood is being labelled correctly when sold, identifying how often salmon stray from their streams of origin, detecting seafood diseases, and measuring the extent of fisheries-induced evolution. 

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