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105 posts in Research

Old-growth fishes are going missing through fishing

In 2011, National Marine Fisheries Service announced the end of overfishing in the U.S. This achievement was considered an important milestone for fishery management. Six years later, a study in Current Biology by Dr. Lewis Barnett (previous postdoctoral researcher) and Prof. Trevor Branch from School of Aquatic and Fishery Sciences revealed a significant decline of old-growth fishes around globe, including the U.S. 

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Why do some species associate together? Habitat is the key, not randomness

The species found in a particular place (“species assemblages”) differ from those found in other places, and figuring out why this is so has occupied the minds of ecologists since the mid-20th century. Currently two theories dominate: the niche theory, and the neutral theory. The niche theory holds that species assemblages result from species migrating into a particular place, and then either thriving or leaving based on how good of a match they are to the habitat and other living organisms (the “niche”) in that place. 

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To reduce human infections, control the snails

Schistosomiasis (also known as billharzia) is a parasitic flatworm that infects a quarter of a billion people worldwide, mostly in tropical countries. If left untreated, it causes chronic pain and diseases of the liver and kidney, and kills up to 200,000 people annually. In recent years, control of the disease has focused on mass-treating humans with a drug called praziquantel, instead of reducing the prevalence of snails that are a required part of the parasite’s life cycle. 

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Fewer big and old Chinook salmon in the Pacific

Chinook salmon (king salmon) are the most prized salmon in the Pacific because of their large size. But now an analysis shows that the oldest Chinook salmon are disappearing, and their size is also declining, and these patterns are seen from California to western Alaska and in both wild and hatchery Chinook salmon. The research by SAFS researchers Jan Ohlberger and Daniel Schindler, and their coauthors Eric Ward and Bert Lewis, appears in the journal Fish and Fisheries, and was highlighted in UW News. 

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An overlooked carbon source to an important freshwater fishery may be under threat

By Ben Miller, SAFS student
When you first arrive at the community of Kampong Phluk, your neck cranes up bamboo stilts to meet the chatter of families in houses high above. From the top of what guidebooks call “bamboo skyscrapers,” locals gaze over the tops of submerged trees, a glittering, island Buddhist temple, and clusters of floating fishing villages in the distance. 

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Baby salmon use the earth’s magnetic field to figure out which way is up

Salmon are capable of using the Earth’s magnetic field as a part of their built-in navigating skills to home back to their streams of birth. Now it has been discovered that young salmon emerging from the gravel also use the Earth’s magnetic field to figure out which way is up. Salmon eggs are laid in gravel nests, and the young salmon remain in the gravel until all of the attached yolk reserves are finished, then they emerge to live out in the open water. 

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With sea ice loss, beluga whales make longer and deeper feeding dives in the same places

Satellite tracking devices on beluga whales in the Arctic show how they reacted to far lower sea ice concentrations in recent years. Instead of shifting where they feed, as might have been expected, beluga whales continued to feed in similar (but now largely ice-free) places. However, where dive data were available, their dives were significantly longer and deeper than in years with higher ice concentrations. 

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Narwhals prefer serene glaciers over rambunctious glaciers

Combining data from glaciers with tracking devices on narwhals, reveals that these elusive marine mammals prefer glaciers that calve infrequently over active calving glaciers. The research, to be presented by SAFS professor Kristin Laidre at the Ocean Sciences Meeting next week, shows narwhals congregating at the outlets of serene glaciers in Greenland’s Melville Bay. Prof. Laidre speculates that the cold fresh water melting off the glacier may stun fish, making them easy prey for the hunting narwhals, while active glaciers produce more silt-filled waters that are harder to hunt in. 

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What is ecosystem-based fisheries management?

The intent of ecosystem-based fisheries management is to move beyond managing each species separately, and to also consider interactions with other species and ecosystem functioning, as well as human benefits such as food, revenue and recreation. A new paper shows that, in practice, people have very different opinions about which management actions could be classed as ecosystem-based. Furthermore, it is highly unlikely that any particular fishery would be able to meet all of the items on a checklist of possible ecosystem-based actions. 

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When do ecological interactions matter in fisheries?

Nearly all fisheries management is based on assessing one species at a time, ignoring any interactions with other species. Many have claimed that including these interactions will improve management and lead to greater fisheries profits. A new paper tests whether precise information on species interactions improves economic performance in fisheries. Somewhat reassuringly, economic value was not markedly lower if managers assumed that an incorrect type of interaction was true. 

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