Background Articles

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.

Once one of the most common cetaceans in the Mediterranean Sea, the short-beaked common dolphin has declined throughout the region since the 1960s and in 2003 this population was classified as Endangered in the International Union for Conservation of Nature (IUCN) Red List. Here, we document the species’ precipitous decline in eastern Ionian Sea coastal waters across 13 yr. While 150 animals were present in the study area (1050 km2) in 1996, only 15 were observed in 2007. A 12 mo assessment of fishing effort and catch, together with circumstantial evidence, suggests that the decline was caused largely by prey depletion resulting from overfishing. We analyzed the impacts of various fishing gear and estimated the degree of resource overlap between common dolphins and local fisheries. The total biomass removed annually by 308 fishing boats in the study area averaged 3571 t, while that consumed by common dolphins was 17 t. Resource overlap between common dolphins and fisheries—expressed as an average Pianka index of 0.5—differed according to fishing gear, being higher for purse seiners (0.7) and beach seiners (0.4) and lower for bottom trawlers (0.1), trammel boats (0.2) and longliners (0.0). Only about 10 active purse seiners (4% of the total active fishing fleet) were responsible for 33% of the biomass removal, and likely had the greatest impact on prey of common dolphins. This study indicates a high risk of local disappearance of common dolphins in the very near future, unless fishery management measures are implemented immediately. Purse seining should be the main management target.

Phytoplankton blooms are increasingly conspicuous along the world's coastlines, and the toxic effects of these blooms have become a major concern. Nutrient enrichment often causes phytoplankton blooms, which decrease water transparency, but little is known about the effects of such light regime changes on whole communities of the continental shelf. A series of simulations designed to evaluate the potential effects of shading by phytoplankton blooms on community organization were conducted using a balanced trophic model of the West Florida Shelf ecosystem and the Ecopath with Ecosim modeling approach. Many functional groups in the system were predicted to decline as benthic primary production was inhibited through shading by phytoplankton, especially when associated biogenic habitat was lost. Groups that obtain most of their energy from planktonic pathways increased when shading impact and associated structural habitat degradation were complemented by enhanced phytoplankton production. Groups predicted to decline as the result of shading by plankton blooms include seabirds, manatees, and a variety of demersal and benthic fishes and invertebrates. Some counterintuitive predictions of declines (mackerel, seabirds, and surface pelagics) resulted because these groups are somewhat dependent on benthic primary production. The overall effect of the simulated bloom-associated shading of benthic primary producers resembled a trophic cascade where the number of full cycles of biomass gains and losses was approximately equal to the number of trophic levels in the system (4.7). (C) 2003 Elsevier B.V. All rights reserved.

"We never know for sure how they died, but it does seem like a lot of the evidence points to killer whale predation," Steve Ferguson, a research scientist with Fisheries and Oceans Canada, said Thursday.