Background Articles

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.

Warmer temperatures in the Arctic may lead to more, and larger, wolf spiders. But this might be good for the region, according to a new study released in the journal Proceeding of the National Academy of Sciences.

Ten caribou herds in Canada's West are on the verge of dying out. For one amateur filmmaker who spent a decade documenting what he thought would be a conservation success story, the recent decline is like a 'huge kick in the gut.'

Scientists aren't sure what is causing this whirlpool of algae but believe it's likely to cause a marine dead zone.

A new project will test ticks found in Alaska to see if the tiny, blood-sucking arachnids carry the pathogens that cause Lyme disease, tularemia or other illnesses.

Nematodes moving and eating again for the first time since the Pleistocene age in major scientific breakthrough, say experts.

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

Blue-green algae has bloomed again in Lake Okeechobee, filling waterways with putrid sludge that can contaminate local water and marine animals.

ALBANY - After years of trying to slow a voracious Chinese beetle that is decimating ash trees, state environmental officials are waving the white flag: The Department of Environmental Conservation dropped a logging quarantine, and said it might be time to cut healthy trees still uninfested. In a brief notice posted online Wednesday, the DEC repealed logging restrictions that had failed to contain the spread of the emerald ash borer (EAB) by limiting shipments of ash. The state created the quarantine in 2015 to slow the insect, which is a shiny green beetle about the size of a penny. The borer likely will ultimately bring about the end of the state's 700 million ash trees - down from earlier estimates of 900 million ash trees before the beetles' arrival - and forever change an industry that uses ash to produce bats for major league baseball.

Culturally vital, ecologically unique, and economically valuable, the yellow cedar’s fate is closely tied to snow

UkrAgroConsult on Tuesday cut its forecast for Ukraine's 2018/19 crop year wheat harvest and exports due to a severe drought across the country during spring and the first half of summer.

A study of more than 1,700 glaciers on northern Ellesmere Island found six per cent of ice coverage disappeared between 1999 and 2015

An increase in carbon emissions are showing up not only in the air, but also in water. Now researchers and shellfish farmers are teaming up to see how marine plants can help stave off the effects of ocean acidification. Special correspondent Jes Burns of Oregon Public Broadcasting reports.

Several serious diseases are in and around the Czech Republic, If you're planning on staying in Prague for any length of time, it makes sense to familiarize yourself with the healthcare options available in the city. Nothing is more important than your health!

PROVIDENCE, R.I. – It may be time for local eateries to explore black sea bass recipes. Warmer waters off Rhode Island have caused a spike for this species, and loosened regulations are reeli…

Salmon used to be infrequent visitors to the Mackenzie River and communities of the Arctic, but more species have begun to show up in the North more often and in greater numbers than ever before.

Insect populations are declining dramatically in many parts of the world, recent studies show. Researchers say various factors, from monoculture farming to habitat loss, are to blame for the plight of insects, which are essential to agriculture and ecosystems.

Water quality in Anchorage's lakes is generally good, but swimmer's itch is a risk.

Dataset from Dr. Brian Burke (NOAA; brian.burke@noaa.gov); derived from surface trawls taken during NOAA Northwest Fisheries Science Center Juvenile Salmon & Ocean Ecosystem Survey (JSOES).

The divide between Atlantic and Arctic isn’t just geographical, it’s physical. And the physics are changing.