Background Articles

We examined the effects of temperature and salt concentration on growth of the freshwater oomycete Saprolegnia parasitica that has recently (since 2013) been found to infect an important subsistence fish (in Iñupiaq, Aanaakłiq; broad whitefish, Coregonus nasus) on the Colville River in Nuiqsut, Alaska. Using two confirmed isolates (one from the Colville River and another from a southern British Columbia aquaculture facility), we tested the following hypotheses: (1) the isolate from Alaska will grow at a greater rate than the isolate from British Columbia at lower temperatures, (2) the isolate from British Columbia will grow at a greater rate at higher temperatures than the Alaska isolate, and (3) increasing salinity will reduce the growth rate of both isolates similarly at all temperatures. In addition, we used local observations—subsistence fishers and observations asso- ciated with scientific monitoring—to assist in interpreting the potential implications of our experi- mental results in the context of these environmental observations. In the habitat relevant to this study, water temperature ranges between <0°C and 18°C, and salinity ranges between 0 and 30 parts per thousand due to a seasonal (and occasional west wind-driven) saltwater intrusions. No statistically significant differences were detected in growth rate or salt tolerance between the two isolates at the temperatures and salinities tested; high temperature (24°C) and low salt concentra- tion are associated with the highest growth rate for both isolates. From our lab study, one might conclude that the peak host colonization would occur during the seasonal period of warmest water temperature; however, the observations by local fishers and biologists show this not to be the case. We conclude that, at this time, we do not have evidence that peak warm water is the primary cause of an increased incidence of infection by this freshwater mold. Although indirect and lag analysis of temperature and timing of infection were not part of this study, we note that there is a greater role of complex interactions among biotic and abiotic factors (including temperature) that may predis- pose some individuals in the population to become infected during spawning season.

Why the "Cluster 5" coronavirus mutation in fur farms has led to a nationwide cull and a political outcry.

People carried the coronavirus onto mink farms in the Netherlands, starting a viral back-and-forth that ended up with 68% of fur farm workers and their close associates infected, researchers reported Tuesday.

New study spotlights influenza virus that could wreak havoc if it adapts to humans.

Wild salmon have higher rates of the parasites when ocean fish farms are near, research shows

The world’s biggest reindeer population is up for big vaccination as regional authorities in the Yamal-Nenets Autonomous Okrug act to stave off outbreaks of anthrax.

Biologists have to figure out how to monitor salmon populations in rural communities without the danger of bringing the coronavirus into those communities.

Feather, fur or fin, all creatures contend with viruses.

Even those athletes of our rivers, Atlantic salmon, usually aren’t as healthy as they look.

A study of tissue samples taken from 150 Atlantic salmon found 14 separate infectious

The Arctic possesses frozen pathogens from past contagions, raising fears that climate change could unleash them as melting permafrost reveals the corpses of their victims.

In big and small ways, a pandemic has altered what Anchorage feels like to live in, from coffee to court to riding the bus.

With the number of COVID-19 cases outside of China increasing 13-fold, the World Health Organization declared the outbreak a global pandemic on Thursday, urging governments “to take urgent and aggressive action” to stop its spread.

Scientists sampling ice cores from a glacier in China discovered 28 viruses that had been frozen in time for as long as 15,000 years, and were not previously known to mankind.

As Australia experiences record-breaking drought and bushfires, koala populations have dwindled along with their habitat, leaving them “functionally extinct.”

As sea ice in the Arctic decreases due to climate change, it’s opening the way for more than cruise ship travel. Scientists have found evidence that links the decline of sea ice to the emergence of a virus in Arctic marine mammals that has killed thousands of seals in European waters.

When scientists found that Alaska sea otters were exposed to a sometimes-deadly virus that plagues seals in the North Atlantic, they were puzzled. Phocine distemper virus had not been previously found in Alaska waters.

When sea otters in Alaska were diagnosed with phocine distemper virus (PDV) in 2004, scientists were confused. The pathogen in the Morbillivirus genus that contains viruses like measles had then only been found in Europe and on the eastern coast of North America.

After kneeling in defrosted marine mammal goo ... doctors treated me for a seal finger infection," Peterson wrote. Seal finger is a bacterial infection that hunters contract from handling the body parts of seals. The only seals Peterson had handled were those in the log cabin. Those seals had been frozen in permafrost for decades.

Climate change has warmed the waters east of Tasmania at four times the speed of the global average. But the heatwave of the southern summer of 2015/2016 was something exceptional, damaging fisheries and bringing new species to the island. It's a sign of things to come, say the researchers examining these events.

Warming Arctic temperatures can create an environment friendly to bacterial infections like anthrax, an infection spread by contact with bacterial spores, which plant-eating animals may eat or breathe in while grazing.