Background Articles

The toxic algae bloom has already been named as the killer or suspected killer of more than 100 manatees since the spring.

Foraging strategies and their resulting efficiency (energy gain to cost ratio) affect animals' survival and reproductive success and can be linked to population dynamics. However, they have rarely been studied quantitatively in free-ranging animals. We investigated foraging strategies and efficiencies of wild northern fur seals Callorhinus ursinus during their breeding season to understand potential links to the observed population decline in the Bering Sea. We equipped 20 lactating females with biologgers to determine at-sea foraging behaviours. We measured energy expenditure while foraging using the doubly-labelled water method, and energy gained using (1) the types and energy densities of prey consumed, and (2) the number of prey capture attempts (from acceleration data). Our results show that seals employed 2 foraging strategies: one group (40\%) fed mostly in oceanic waters on small, high energy-density prey, while the other (60\%) stayed over the shallow continental shelf feeding mostly on larger, lower quality fish. Females foraging in oceanic waters captured 3 times more prey, and had double the foraging efficiencies of females that foraged on-shelf in neritic waters. However, neritic seals made comparatively shorter trips, and likely fed their pups similar to 20 to 25\% more frequently. The presence of these strategies which either favor foraging efficiency (energy) or frequency of nursing (time) might be maintained in the population because they have similar net fitness outcomes. However, neither strategy appears to simultaneously maximize time and energy allocated to nursing, with potential impacts on the survival of pups during their first year at sea.

From floods to fires, drought to coastal erosion, climate change is already having an impact on Canada's communities, landscapes and wildlife

It’s well established that Arctic ice is changing in dramatic ways. As the climate warms, ice coverage is decreasing, the amount of multiyear ice has gone down significantly and in

Reductions in sea ice in the Arctic have a clear impact on animals such as polar bears that rely on frozen surfaces for feeding, mating and migrating. But sea ice loss is changing Arctic habitat and affecting other species in more indirect ways, new research finds.

Late last year one of the world’s largest credit rating agencies announced that climate change would have an economic impact on the U.S.

Polar bears live in a remote and inhospitable environment far from most human settlements. For most biologists, opportunities to observe these animals are fleeting. In fact, scientists' main resources for understanding basic behaviors of polar bears on sea ice are observations of polar bear behavior and foraging rates made by Canadian biologist Ian Stirling more than 40 years ago, combined with local traditional knowledge from Arctic indigenous peoples.

Serious and unusual outbreaks of illness from eating raw or undercooked walrus to call attention to the risks.

In the Bering Sea, near the edge the continental shelf, fishermen are trying to escape a predator that seems to outwit them at every turn, stripping their fishing lines and lurking behind their vessels.

Since June 7, 2017, elevated North Atlantic right whale (Eubalaena glacialis) mortalities have been documented, primarily in Canada and were declared an Unusual Mortality Event.  In 2017, there was a total of 17 confirmed dead stranded whales (12 in Canada; 5 in the United States) and in 2018, three whales stranded in the United States. In 2019, two whales have stranded in Canada.

The whales seem to have died from starvation and washed up on shore from California to Alaska

The latest research shows that diminishing Arctic sea ice caused by climate change is forcing some species to travel further to find food or look for alternative food sources.

These big, blubbery beasts are sensitive souls that dislike being disturbed by people. Unfortunately for them, warming Arctic temperatures are bringing more shipping and tourism to their home waters.

Sixty years ago, around the time when Matthew Rexford's father's father was turning the ground to build his own ice cellar as a proud whaling captain, there were 12 of these such cellars in Kaktovik. Today there is only one left.

Trace 134Cs in northern fur seal tissue suggests that the population under study had been minimally exposed Fukushima-derived radionuclides. Despite this inference, the radionuclide quantities detected are small and no impact is expected as a result of the measured radiation exposure, either in northern fur seal or human populations consuming this species.

Populations of marine wildlife have plummeted by a half on average over the past 40 years with some species suffering far greater declines as a result of habitat loss, overfishing, rising sea temperatures and worsening ocean acidity, a major report has found.

The "unprecedented" warm water in the Pacific caused a massive toxic algae bloom from California to Alaska.

A recent study shows that polar bears' mercury levels are declining as melting ice drives them onshore. But is it all good news? Read on.

When wild birds are a big part of your diet, opening a freshly shot bird to find worms squirming around under the skin is a disconcerting sight. That was exactly what Victoria Kotongan saw in October, 2012, when she set to cleaning two of four spruce grouse (Falcipennis canadensis) she had taken near her home in Unalakleet, on the northwest coast of Alaska.

Our results showed that local fisheries have negatively impacted the marine biodiversity of the ecosystem causing sharp declines of common dolphins and major fish stocks and weakening the robustness of the marine food web.