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Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas

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A southern resident orca preying on salmon in the Salish Sea near Seattle. Credit: Su Kim/NOAA Fisheries

In the Pacific Northwest and British Columbia, scientists have been sounding the alarm about the plight of southern resident orcas. Annual counts show that population numbers, already precarious, have fallen back to mid-1970s levels. Most pregnancies end in miscarriage or death of the newborn. They may not be catching enough food. And many elderly orcas—particularly post-reproductive matriarchs, who are a source of knowledge and help younger generations—have died.

With just 73 individuals left, conservationists and members of the public alike are concerned that southern resident orcas may not survive.

Yet over the same period, the region’s northern resident orcas, who have a similar diet and an overlapping territory, grew steadily in . Today, there are more than 300 northern resident orcas, leaving scientists wondering why these two similar but distinct populations have had such dissimilar fates over the past half century.

A new study led by scientists at the University of Washington and NOAA Fisheries reveals that the two populations differ in how they hunt for salmon, their primary and preferred food source. The research, done by an international team of government, academic and nonprofit researchers, was published in Behavioral Ecology.

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“For northern resident orcas, females were hunting and capturing more prey than males. For southern resident orcas, we found the opposite: The males were doing more hunting and capturing than females,” said lead author Jennifer Tennessen, a senior research scientist at the University of Washington’s Center for Ecosystem Sentinels.

“We also found that if their mother was alive, northern resident adult males hunted less, which is consistent with previous work, but we were surprised to see that southern resident adult males hunted more. Adult females in both populations hunted less if they had a calf, but the effect was strongest for southern residents.”

Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas
A southern resident orca in 2010. Credit: NOAA

The study’s five years of observational data show that southern resident males catch 152% more salmon per hour than females. In other words, for every two fish a southern female caught, a southern male would catch five. For the growing northern resident population, the trend is flipped: females caught 55% more salmon per hour than males.

This is the first study to track the underwater pursuit, hunting and prey-sharing behaviors of both northern and southern resident orcas. Their findings reveal that, though the two populations overlap significantly in territory and have similar social structures and reproductive behavior, they should not be treated identically for conservation purposes.

“In the past, we’ve made assumptions about these populations and filled in the gaps when designing interventions, particularly to help the southern resident orcas,” said Tennessen, who conducted this study while she was a research scientist with NOAA’s Northwest Fisheries Science Center. “But what we found here are strikingly different patterns of behavior with something as critical to survival as foraging. And as we develop management strategies, we really need to consider these populations differently.”

NOAA scientists and an international team of collaborators temporarily tracked the movement, sounds, depth and feeding behaviors of 34 northern and 23 southern resident adult orcas non-invasively from 2009 to 2014 using “Dtags,” cellphone-sized digital devices. Dtags attach via suction to the back of an orca and, for this study, were programmed to fall off hours later and float back to the surface so the researchers could collect them and download their data.

As the name would suggest, northern resident orcas have a more northerly distribution, preferring waters around Vancouver Island and the Queen Charlotte Strait. In contrast, core areas for southern resident orcas hug the southern reaches of Vancouver Island, inland waters surrounding the San Juan Islands, Puget Sound and the Washington coast.

Both populations were devastated by the capture of orcas for theme parks, a practice that ended in the 1970s. Since then, northern resident orcas have increased steadily, seeing at least 50% growth since 2001.

Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas
A southern resident orca calf and its mother in 2004. Credit: NOAA National Ocean Service

Both populations hunt for salmon using echolocation. Adult orcas can dive at least 350 meters—or 1,150 feet—to pursue fish on their own, though they often bring kills to the surface to share with others.

Pods travel between the outflows of major rivers and streams in British Columbia and Washington, and have been heavily impacted by dams that have reduced salmon runs. Increased vessel traffic and noise in the Salish Sea—from tourism, recreation and shipping—have also negatively affected these populations, particularly the southern resident orcas, according to Tennessen.

This new study showed that southern residents had fewer successful hunts overall, indicating that they were presumably catching less food. This impact is particularly evident with young mothers.

“In both populations, a mother with a young calf foraged less than other females, possibly due to the risk of leaving the calf temporarily with ‘a babysitter’—another adult—while she hunts, or because of the time demands of nursing a calf,” said Tennessen. “But for southern resident females, which are more prone to disturbance and stress from vessel traffic, there was an outsized effect: Our study found no instance of a southern resident female with a young calf who successfully carried out a hunt.”

The study also has much to say about the impact of elderly female orcas on their adult sons. Both northern and southern resident orcas are grouped into matriarchal clans, often led by post-reproductive females. They also help feed their adult sons even, as a recent study led by the nonprofit Center for Whale Research showed, at the expense of their own reproductive capacity.

The new study adds complexity to the role of elderly females. Among northern resident orcas, adult males with a living mother hunted less than adult males without a living mother, perhaps because the mother still provides food. But among southern resident orcas, the opposite is true: Adult males with a living mother hunted more.

Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas
A NOAA scientist observing southern resident orcas from a research boat. Credit: Northwest Fisheries Science Center/NOAA Fisheries

“These unexpected differences left us scratching our heads. It is possible that southern resident adult males could be sharing with other members of their group, including their mothers, to help out, especially since an adult male’s survival is strongly linked to his mother’s survival,” said Tennessen.

“Relatedly, southern resident matriarchs may be leading the group to areas where their adult sons may be able to capture more prey, since healthier sons might be more successful at mating and passing along some of their mothers’ genes. We need more studies to determine what role the presence—or absence, for southern resident orcas—of matriarchs has on male foraging behavior.”

Future studies on the behaviors of northern and southern resident orcas could bring these differences to the surface, as could studies of Alaska resident orca populations, which forage for salmon farther north, where salmon stocks are generally healthier. Such comparative studies can help isolate cause and effect, said Tennessen.

“Understanding how healthy populations behave can provide direction and goals for management of unhealthy populations,” said Tennessen. “Future comparisons to healthy fish-eating populations could help us understand whether the divergent behavior we’re seeing in the southern residents is indicative of a population trying to survive.”

More information:
Jennifer B Tennessen et al, Divergent foraging strategies between populations of sympatric matrilineal killer whales, Behavioral Ecology (2023). DOI: 10.1093/beheco/arad002

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University of Washington

 

Citation:
Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas (2023, March 10)
retrieved 10 March 2023
from https://phys.org/news/2023-03-northern-southern-resident-orcas-differently.html

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Kevin Neil Friesen Obituary 2024 – Crossings Funeral Care

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It is with heavy hearts that we announce the peaceful passing of Kevin Neil Friesen age 53 on Thursday, March 28, 2024 at the Bethesda Regional Health Centre.

A funeral service will be held at 2:00 pm on Thursday, April 4, 2024 at the Bothwell Christian Fellowship Church, with viewing one hour prior to the service.

A longer notice to follow.  

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Spring allergies: Where is it worse in Canada? – CTV News

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The spring allergy season has started early in many parts of Canada, with high levels of pollen in some cities such as Toronto, Ottawa and Montreal.

Daniel Coates, director of Aerobiology Research Laboratories in Ottawa, expects the elevated amounts to continue next week for places, such as most of Ontario, if the temperature continues to rise. Aerobiology creates allergen forecasts based on data it collects from the air on various pollens and mould spores.

Pollens are fertilizing fine powder from certain plants such as trees, grass and weeds. They contain a protein that irritates allergy sufferers.

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Although pollen levels declined after a cold spell in some places, he said they are soaring again across parts of Canada.

“So the worst is definitely British Columbia right now, followed by Ontario and Quebec and then the Prairies and Atlantic Canada for the upcoming weeks,” said Coates in a video interview with CTVNews.ca. “We are seeing pollen pretty much everywhere, including the Maritimes.”

He said pollen has increased over the past 20 years largely due to longer periods of warm weather in Canada.

Meanwhile, the Maritimes is one of the best places to live in Canada if you have seasonal allergies, in part because of its rocky territory, Coates said.

With high levels of cedar and birch pollen, British Columbia is the worst place for allergy sufferers in Canada, he added.

“British Columbia is going strong,” Coates explained, noting the allergy season started “very early” in the province in late January. “It has been going strong since late January, early February and it’s progressing with high levels of pollen, mostly cedar, but birch as well, and birch is highly allergenic.”

Causes of high pollen levels

Coates expects a longer allergy season if the warm weather persists. He notes pollen is increasing in Canada and worldwide, adding that in some cases the allergy season is starting earlier and lasting longer than 15 years ago.

He says tree pollen produced last year is now being released into the air because of warmer weather.

“Mother nature acts like a business,” he said. “So you have cyclical periods where things go up and down. … So when it cooled down a little bit, we saw (pollen) reduce in its levels, but now it’s going to start spiking.”

Along with warmer weather, another factor in higher pollen levels is people planting more male trees in urban areas because they don’t produce flowers and fruits and are less messy as a result, he said. But male trees produce pollen while female ones mostly do not.

Moulds

Coates said moulds aren’t as much of a problem.

“They’ve been mainly at lower levels so far this season,” he explained. “Moulds aren’t as bad in many areas of Canada, but they’re really, really bad in British Columbia.”

In B.C., moulds are worse because of its wet climate and many forested areas, he said.

Coping with allergies

Dr. Blossom Bitting, a naturopathic doctor and herbal medicine expert who works for St. Francis Herb Farm, says a healthy immune system is important to deal with seasonal allergies.

“More from a holistic point of view, we want to keep our immune system strong,” she said in a video interview with CTVNews.ca from Shediac, N.B. “Some would argue allergies are an overactive immune system.”

Bitting said ways to balance and strengthen the immune system include managing stress levels and getting seven to nine hours of restful sleep. “There is some research that shows that higher amounts of emotional stress can also contribute to how much your allergies react to the pollen triggers,” Bitting said.

Eating well by eating more whole foods and less processed foods along with exercising are also important, she added. She recommends foods high in Omega-3 Fatty Acids such as flaxseeds, flaxseed oil, walnuts and fish. Fermented foods with probiotics such as yogurt, kimchi and miso, rather than pasteurized ones, can keep the gut healthy, she added. Plant medicines or herbs such as astragalus, reishi mushrooms, stinging nettle and schisandra can help bodies adapt to stressors, help balance immune systems or stabilize allergic reactions, she said.

To cope with allergies, she recommends doing the following to reduce exposure to pollen:

  • Wear sunglasses to get less pollen into the eyes;
  • Wash outdoor clothes frequently, use outer layers for outside and remove them when you go inside the house;
  • Use air purifiers such as with HEPA (high efficiency particulate air) filters;
  • Wash pets and children after they go outside;
  • Keep the window closed on days with high pollen counts.

Mariam Hanna, a pediatric allergist, clinical immunologist and associate professor with McMaster University in Hamilton, Ont., says immunotherapy can help patients retrain their bodies by working with an allergist so they become more tolerant to pollens and have fewer symptoms.

“Some patients will need medications like over-the-counter antihistamines or speaking with their doctor about the right types of medications to help with symptom control,” she said in a video interview with CTVNews.ca.

Coates recommends people check pollen forecasts and decrease their exposure to pollen since no cure exists for allergies. “The best is knowing what’s in the air so that you can adjust your schedules, or whatever you’re doing, around the pollen levels.”

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Do you need a spring COVID-19 vaccine? Research backs extra round for high-risk groups

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Recent studies suggest staying up-to-date on COVID shots helps protect high-risk groups from severe illness

New guidelines suggest certain high-risk groups could benefit from having another dose of a COVID-19 vaccine this spring — and more frequent shots in general — while the broader population could be entering once-a-year territory, much like an annual flu shot.

Medical experts told CBC News that falling behind on the latest shots can come with health risks, particularly for individuals who are older or immunocompromised.

Even when the risk of infection starts to increase, the vaccines still do a really good job at decreasing risk of severe disease, said McMaster University researcher and immunologist Matthew Miller.

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Who needs another COVID shot?

Back in January, Canada’s national vaccine advisory body set the stage for another round of spring vaccinations. In a statement (new window), the National Advisory Committee on Immunization (NACI) stated that starting in spring 2024, individuals at an increased risk of severe COVID may get an extra dose of the latest XBB.1.5-based vaccines, which better protect against circulating virus variants.

That means:

  • Adults aged 65 and up.
  • Adult residents of long-term care homes and other congregate living settings for seniors.
  • Anyone six months of age or older who is moderately to severely immunocompromised.

The various spring recommendations don’t focus on pregnancy, despite research (new window) showing clear links between a COVID infection while pregnant, and increased health risks. However, federal guidance does note that getting vaccinated during pregnancy can protect against serious outcomes.

Vaccinated people can also pass antibodies to their baby through the placenta and through breastmilk, that guidance states (new window).

What do the provinces now recommend?

Multiple provinces have started rolling out their own regional guidance based on those early recommendations — with a focus on allowing similar high-risk groups to get another round of vaccinations.

B.C. is set to announce guidance on spring COVID vaccines in early April, officials told CBC News, and those recommendations are expected to align with NACI’s guidance.

In Manitoba (new window), high-risk individuals are already eligible for another dose, provided it’s been at least three months since their latest COVID vaccine.

Meanwhile Ontario’s latest guidance (new window), released on March 21, stresses that high-risk individuals may get an extra dose during a vaccine campaign set to run between April and June. Eligibility will involve waiting six months after someone’s last dose or COVID infection.

Having a spring dose is particularly important for individuals at increased risk of severe illness from COVID-19 who did not receive a dose during the Fall 2023 program, the guidance notes.

And in Nova Scotia (new window), the spring campaign will run from March 25 to May 31, also allowing high-risk individuals to get another dose.

Specific eligibility criteria vary slightly from province-to-province, so Canadians should check with their primary care provider, pharmacist or local public health team for exact guidelines in each area.

WATCH: Age still best determines when to get next COVID vaccine dose, research suggests:

 

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Age still best determines when to get COVID vaccines, new research suggests

It’s been four years since COVID-19 was declared a pandemic, and new research suggests your age may determine how often you should get a booster shot.

Why do the guidelines focus so much on age?

The rationale behind the latest spring guidelines, Miller said, is that someone’s age remains one of the greatest risk factors associated with severe COVID outcomes, including hospitalization, intensive care admission and death.

So that risk starts to shoot up at about 50, but really takes off in individuals over the age of 75, he noted.

Canadian data (new window) suggests the overwhelming majority of COVID deaths have been among older adults, with nearly 60 per cent of deaths among those aged 80 or older, and roughly 20 per cent among those aged 70 to 79.

People with compromised immune systems or serious medical conditions are also more vulnerable, Miller added.

Will people always need regular COVID shots?

While the general population may not require shots as frequently as higher-risk groups, Miller said it’s unlikely there will be recommendations any time soon to have a COVID shot less than once a year, given ongoing uncertainty about COVID’s trajectory.

Going forward, I suspect for pragmatic reasons, [COVID vaccinations] will dovetail with seasonal flu vaccine campaigns, just because it makes the implementation much more straightforward, Miller said.

And although we haven’t seen really strong seasonal trends with SARS-CoV-2 now, I suspect we’ll get to a place where it’s more seasonal than it has been.

In the meantime, the guidance around COVID shots remains simple at its core: Whenever you’re eligible to get another dose — whether that’s once or twice a year — you might as well do it.

What does research say?

One analysis, published in early March in the medical journal Lancet Infectious Diseases (new window), studied more than 27,000 U.S. patients who tested positive for SARS-CoV-2, the virus behind COVID, between September and December 2023.

The team found individuals who had an updated vaccine reduced their risk of severe illness by close to a third — and the difference was more noticeable in older and immunocompromised individuals.

Another American research team from Stanford University recently shared the results from a modelling simulation looking at the ideal frequency for COVID vaccines.

The study in Nature Communications (new window) suggests that for individuals aged 75 and up, having an annual COVID shot could reduce severe infections from an estimated 1,400 cases per 100,000 people to around 1,200 cases — while bumping to twice a year could cut those cases even further, down to 1,000.

For younger, healthier populations, however, the benefit of regular shots against severe illness was more modest.

The outcome wasn’t a surprise to Stanford researcher Dr. Nathan Lo, an infectious diseases specialist, since old age has consistently been a risk factor for severe COVID.

It’s almost the same pattern that’s been present the entire pandemic, he said. And I think that’s quite striking.

More frequent vaccination won’t prevent all serious infections, he added, or perhaps even a majority of those infections, which highlights the need for ongoing mitigation efforts.

Lauren Pelley (new window) · CBC News

 

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