Friday , October 22 2021

The Coeur d 'Alene Press – Food and Health, For endangered orcas, this is a hunger game



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Over the past few years, Snake River salmon in Idaho and Puget Sound orcas have been linked in decades of fighting over the fate of the four lower Snake River Dam and whether they should be moved to save fish.

Orcas, especially the population killer whales in the south, are in trouble and have for some time. It became a sharp focus this summer when a member of J-pod, the Orcas Puget Sound subgroup, brought calves that died for 17 days and attracted media attention throughout the world.

The Pope faces a lack of food, noise from busy ships on Puget Sound and accumulation of pollutants in their body fat. All three are connected, but what is the basis is that whales don't get enough to eat, and what they eat is mostly salmon.

That's where the salmon lay eggs in the entrance of the Snake River Basin. Whales prefer chinook salmon and eat a number of different stocks along the US and Canada's West Coast. Most of the year, from spring to autumn, whales prey on chinook returning to empty rivers to Puget Sound and the Salish Sea, especially the Fraser River in Canada. But they also left inland waters in the fall to travel along the coast looking for salmon, and to a lesser extent other species, before returning in the spring.

One of the shares targeted by the pope during this period was originating from and returning to the Columbia River and its tributaries. That brings the Snake River. Orca supporters have formed a philosophical and strategic alliance with supporters of the Snake River salmon who believe breaking four dams on the lower Snake River will significantly increase the number of salmon and steelhead from the Snake River Basin. They believe, as many scientists do, that violations of increasing salmon Snake River are enough to trigger recovery.

Violation: How big is the impact?

So how many dams are breaking to help the pope? There is nothing to say for sure, but there are two competing scientific camps and above which the Snake River Chinook run is more important for the pope. Those who believe that orcas are more dependent on Chinook falling from the Columbia river valley and Snake tend to see less of the potential benefits of violations, because the fall of Chinook runs in a better form than spring Chinook runs. And most of the fall of Chinook returning to the Columbia Basin does not originate from the Snake River.

This is the side that the National Oceanic and Atmospheric Fisheries Administration, a body responsible for overseeing efforts to stabilize and restore both whales and fish, has been adopted. In the fact sheet about killer whales and the Snake River dam, the agency said that the fall of Chinook has been going relatively well over the past decade, although their results have declined in recent years due to poor sea conditions.

"In the past decade, adult chinook salmon have returned through the Bonneville Dam on the Columbia River rather than at any other time since the dam was completed in 1938. NOAA Fisheries found that Chinook seeding is more than compensation for fish lost in dams in terms of the total number of chinooks available to whales murderer, "said the body on the fact sheet.

The agency sees the entire Columbia Basin as a place that has done its part to feed whales and wants to see more improvements from other basins.

"The Columbia River and Snake produce more than half of Chinook on the West Coast. This is where the whales come because salmon is here, not because they are lost, "said Michael Milstein, spokesman for NOAA in Portland.

Milstein said it was important to work on all the stocks whales eat.

"They all donate fish to whales at different times of the year in various places," he said. "This is not about one critical river. It's about the diversity of the river and the stock they produce, each with its own history and time of life. "

Those who saw spring chinook from the Columbia and Snake basin because it was more important tended to think breaking could play a significant role. Spring Chinooks are less powerful than autumn Chinook, and Chinooks that have sprung up in the larger Columbia Basin are dominated by the Sungai Ular stock. Fighting the dam will help lower the chinook to a higher level than the autumn chinook, although it will be useful for both to walk.

Orcas: Chinook specialist

One thing is certain, the southern population killer whale is a specialist in Chinook salmon. That makes most of their food all fish, and whales don't eat enough. To determine how to reverse it, NOAA scientists have tried to measure the relative importance of different West Coast Chinook salmon so that they know where it is best to focus their efforts. In rankings, scientists see three factors: if certain stocks appear in the whale's diet; if it appears on the whale's diet during the stressful winter months; and the extent to which stock overlaps in space and time with whales throughout the year.

Based on this system, falling Chinook from the Columbia Basin, including the Chinook Snake River, has a relatively high rating – No. 3 in the list. This is largely due to the fall of Chinook that was available to the pope for most of the year. The southern whale killer will eat in autumn Chinook during extensive widening off the west coast sometime from late fall to around May.

In contrast, Chinook spring is less available for orcas for most of the time the whale is inactive from what scientists call "the outer coast." However, when Chinook spring returns to lay eggs in fresh water, fish gather or are near the mouth of Columbia . This is a short window for whales, but some people believe because of the density of fish at that time, it is an important food source.

"The behavior of falling stocks tends to be more coastal in sea distribution. They are more accessible to whales for a longer period of time, not only during spawning migrations, "said Mike Ford, director of the division of conservation biology at the NOAA Northwest Fisheries Science Center in Seattle.

"While spring run stocks, especially the interior (running) of Snake and Columbia above, their ocean distribution doesn't really overlap with whales at all, except for a period of several months when they return to lay eggs," Ford said. "During that period, they could be very important to the pope."

When scientists stacked data about the strength of Chinook and the health of whales, they found that over the years with good Chinooks, whales have a higher birth rate. In fact, from 2013 to 2015, "there is a baby boom," Ford said.

Ole Shelton, a research ecologist at the Northwest NOAA Fisheries Science Center in Seattle, said there were more scientists who did not know they were doing about how specific stocks of Chinook and southern population killer whales interacted. He called it "a very active research area."

But Shelton said the scientists knew more about the fall of Chinook when it came to their sea distribution than they knew about spring walking.

"Falling Chinook tends to be more to the beach, and they tend to be more south than their Chinook spring counterparts in certain areas. If you look at the distribution of Chinook falls from the Snake River, they tend to be a little north of the river mouth, in Vancouver, the island region and the center of British Columbia and off the coast of Washington, "he said. "Spring Chinooks are far more badly studied, but the general idea is that they tend to go further from the coast and farther north."

Spring Chinook: measure importance

Two of the three Puget Sound pugs from the target of Chinook spring killer whales when they stage fish near the mouth of the Columbia River in March as fish prepare to go to fresh water for spawning.

"I think it is entirely reasonable that the Snake River Spring Chinook run tends to look like a candidate that might be important during that year. They almost certainly aren't that important at other times of the year, "Shelton said. "For that time of year – winter and spring – you will say Snake River spring Chinook might go up a lot higher than other stocks, but if you look at it all year, they fall a little bit. We believe they are not on Puget Sound, Strait of Juan de Fuca, and the Strait of Georgia. "

The importance of spring cannot be concluded, he said.

"I can fully believe that the Snake River Spring Chinook, if there are more of them, will be healthy for the population (killer whales). I can also see which scenario is not correct. It's best to do as much as you can for as many stocks as possible and succeed, "he said.

For Sam Wasser, a professor of conservation biology research, ecology and physiology at the University of Washington, there is no doubt that the Snake River Chinook is important and even important to the pope. Wasser studied blood hormones found in whale droppings which, among others, showed pregnancy rates and stress levels. His team used a new approach to collect whale droppings. They follow behind the whales on the boat and use specially trained dogs to sniff and find whale feces so that they can be crawled from the surface of the sea with a pool of pool cleaners, before they sink or are removed.

He found that 69 percent of all pregnancies that could be detected among the southern population killer whale population failed, and more than 30 percent failed at the end of the semester or at or immediately after birth when the risk for mothers was much higher. Stress from lack of food is likely the cause of failure, Wasser said.

He and others measured two hormones in a whale that showed stress. They found that when the whales returned to the Salish Sea in the spring after eating from the mouth of the Columbia River, the whales showed low pressure. But that is changing rapidly, possibly because Chinook Fraser River is rare in the Salis Sea until mid to late August.

He said the winter when whales hunt off the US and Canada was a tense time for them.

"It was a very difficult time for them. Cold, they have to regulate thermally, they don't have large adult salmon at the mouth of the river, they have all the sizes of fish that are harder to catch. "

After the winter, whales find food that is very fast in the mid to late spring when they target the spring Chinook towards the Snake and Columbia rivers. Chinook's spring stock which drives the furthest upstream is usually the first to appear. They also tend to have a higher fat content to support them when they push upstream. Snake River Chinook dominates the spring chinook that has just returned from the Columbia Basin.

"The Chinook Columbia River that returns early is some of the fatest salmon known," Wasser said. "Running is very big. It is our very recommended work, it is very important to fill (whales) from the harsh winters and also maintain them until Chinook River Fraser runs, which is not until mid-August.

Because Chinooks heading to places like the Clearwater and Salmon rivers have gone so far, they have evolved to be bigger and fatter than other spring Chinin.

"They have to travel around 900 miles in migration. They have to come with lots of fat and start, "Wasser said. "It seems very, very important for this pope. It seems like if there is one very important run, they can do something dramatic (for), this is the Chinook Columbia River. "

That's why many people see dams as something that can help whales. Many papal advocates see it as a potential quick fix. Wasser is not among them.

"I do not say they should immediately violate the dam," he said. "I think this is something that really deserves serious study, and until now, every time you bring that problem, they say we can't go there. I think it needs to be investigated in a very serious way to see if there is a long-term solution. I emphasize the long term. There are many things we can do temporarily. "

Barker can be contacted at [email protected] or at (208) 848-2273. Follow him on Twitter @ezebarker.

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