Grey Whales: Unusual mortality event from 2018 to 2023

[TinWing]

https://phys.org/news/2024-06-wildlife-mystery-gray-whales-san.amp

Perhaps, in hindsight, whaling served the purpose of “culling the herd” and keeping the population of Gray Whales within the carrying capacity of their habitat. Obviously, commercial whaling went too far in that objective, but it might be time to admit artisanal whaling by native cultures and even “traditional” commercial whaling Japan, Iceland or Norway might be in the best interests of certain whale species. I’d go so far as to say that taxpayer dollars might be better spent on promoting whaling among the Inuit and other native cultures than on wildlife biologists and “conservationists” who tend to have a general disregard for non-white and even non-Anglophone cultures.

 

[Arjen]

From the linked piece, what scientists offer as a possible explanation:

Researchers said the die-off from 2018 to 2023, which NOAA called an "unusual mortality event," was likely due to a shortage of food in the Arctic linked to changes in the amount of sea ice, wind patterns and other factors. Whales eat 3,000 pounds or more of food a day, preferring small, shrimp-like crustaceans known as amphipods, along with worms and other tiny creatures that they scoop from the sea floor.
[...]
The roller coaster population—and weird detours into San Francisco Bay—could be related to climate change, or it could be part of the gray whale's natural population fluctuations, said John Calambokidis, a research biologist with Cascadia Research, in Olympia, Washington.
"What is a natural cycle?" he said. "Is this normal? Or something unusual? The ecosystem in the Arctic has changed very rapidly. That's one reason this has scientists' attention."

 

[Shoes31]

I'd imagine that when you remove a predator (human whalers) from the environment, the prey (whale) numbers will explode and likely overpopulate. Over time the numbers will come back down to a number the environment can sustain and all will be in balance.

One could argue that limited whaling would be okay environmentally, but humanity's greed tends to mean that when you open the gates just a crack the gates tend to swing all the way open.

 

[DWG]

Somehow I doubt the natural population level for grey whales was 'the ones that survived whaling'.

 

[southwestforests]

I'd imagine that when you remove a predator (human whalers) from the environment, the prey (whale) numbers will explode and likely overpopulate. Over time the numbers will come back down to a number the environment can sustain and all will be in balance.

Though very much not whales, that brings to mind the following, and maybe some factors in articles do also apply to the situation with the whales,

Managing for White-tailed Deer in Missouri: Setting and Accomplishing Management Goals | MU Extension

White-tailed deer managementThis deer conservation guide is one in a series developed jointly by MU Extension and the Missouri Department of Conservation.Robert A. Pierce IIFisheries and Wildlife State SpecialistSchool of Natural ResourcesBrad MormannPrivate Land ConservationistMissouri...

extension.missouri.edu

Missouri no longer has breeding populations of major predators of adult white-tailed deer. Therefore, deer populations are now primarily managed through hunting in rural, and in some cases urban, areas of the state. Hunters make a management decision each time they choose whether to harvest a deer. As quality deer management (QDM) philosophies are adopted by landowners or wildlife management cooperatives, each hunter will become more aware of how individual harvest decisions can influence the deer herd’s overall health and population demographics.

Influencing population demographics such as adult sex ratio, fawn recruitment and buck age structure requires an understanding of population dynamics. ...

That bit, "requires an understanding of population dynamics." definitely applies to the whale situation.

also,

Missouri deer hunting season regulations are changing in 2023. Here's why.

A hundred years ago, barely 1,000 deer roamed Missouri. There are now more than 1.5 million — conservation officials want to keep it that way.

www.news-leader.com

A hundred years ago, barely 1,000 deer roamed Missouri. Between over-hunting and unsustainable thinking, white-tailed deer were few and far between.

If someone spotted a track in the woods, they would race back to town to share the news, said Jason Isabelle, cervid program supervisor for Missouri Department of Conservation.

"There are people out there that have been around for a while and they'll tell you stories of when they were a kid and just not seeing deer," Isabelle said.

"There was market hunting back then where you could actually harvest deer and sell them in the bigger cities to make a profit," Isabelle said in a phone interview about the 1920s and prior. "At that time, people viewed wildlife populations as inexhaustible resources. There seemed to be so many of them that the thought was, 'Well, we can just take as many as we want, whenever we want, and they'll always be there.' Obviously, that wasn't the case."

A century later, more than 1.5 million deer are now scattered throughout Missouri.

The conservation department wants those numbers to be maintained, which explains the expanded hunting regulations and limits it recently announced, Isabelle said. ...

And that bit of history likewise applies to whales, At that time, people viewed wildlife populations as inexhaustible resources. There seemed to be so many of them that the thought was, 'Well, we can just take as many as we want, whenever we want, and they'll always be there.' Obviously, that wasn't the case."

 

[southwestforests]

the prey (whale) numbers will explode and likely overpopulate. Over time the numbers will come back down to a number the environment can sustain and all will be in balance.

Or balance could be permanently lost within the ocean ecology at large,
illustration via deer analogy again,

Issue: Deer Abundance

ecosystems.psu.edu

Over-abundant deer populations also reduce the diversity of plants and other wildlife species found in the forest. High levels of browsing by deer can completely remove the shrub and tree seedling layers in a forest. Many native wildflower species are also preferred deer foods. These plants are also reduced in abundance or completely eliminated when deer impact is high. With the loss of the understory tree and shrub layer comes a loss in abundance of many other wildlife species. Numerous species of birds which nest in the shrub layer or on the forest floor are reduced in abundance when deer populations rise beyond what the habitat can support.

When deer populations are above the carrying capacity of the land for long periods of time they begin to degrade their habitat. Under these conditions, forest understories become composed predominantly of plants that deer avoid or prefer not to eat. Once this happens, the degraded environment supports only a fraction of the biodiversity it once did.

and

Ecological Impacts of High Deer Densities (Overview)

A growing body of ecological studies (see Waller and Alverson 1997 and Russell et al. 2001 for academic reviews or Ness 2003 for a popular review) suggests that high deer density is directly affecting the composition of woody and herbaceous vegetation and indirectly impacting wildlife. Tree species especially palatable to deer, such as economically valuable oaks, are not regenerating while other species resistant to deer browse, like beech, flourish. The toll on herbaceous plants is also substantial. Local disappearances of numerous plants, such as orchids and lilies, have been documented in woodlands with abundant deer across the East and Midwest. These concerns are especially crucial in protected areas (e.g., nature preserves and national parks) where managers are often attempting to maintain a particular vegetative community.

Beyond the impact on specific trees or other plants, deer can significantly influence wildlife habitat by altering the forest’s composition and structure. For example, in a forest where the understory has been largely eaten by deer, habitat for birds requiring a thick understory will decline. On the other hand, birds that prefer an open understory will benefit. Some ecologists have argued that white-tailed deer are a keystone herbivore because they have such large impacts on forest communities (Waller and Alverson 1997). Waller and Alverson (1997:218) define a keystone species as one that: “(1) affects the distribution or abundance of many other species, (2) can affect community structure by strongly modifying patterns of relative abundance among competing species, or (3) affects community structure by affecting the abundance of species at multiple trophic levels.” It can be argued that deer fit this description because in high densities they affect trees, shrubs, herbaceous plants, birds, and small mammals. In this issue students will examine two studies: one investigating the relationship between deer densities and hemlock regeneration in the Upper Great Lakes region of the U.S. and the other examining deer’s impact on the abundance and diversity of breeding bird populations in northern Virginia.

Although many people assume that deer densities today are far above historical norms, it is surprisingly difficult to know whether this is the case.

 

[Orionblamblam]

Somehow I doubt the natural population level for grey whales was 'the ones that survived whaling'.

Indeed. Until industrial whaling, humans likely had a trivial effect on the population of whales. The minimal whaling being done by the Japanese today is probably on par with what the pre-industrial Inuit and Icelanders and Japanese were doing.

Industrial whaling wiped out not only the gray whales, but all the others. The grays seem to have bounded back faster than everyone else, and have filled all the niches formerly occupied by blue whales and such. And what with the Japanese and Chinese and whatnot stripping the oceans bare of the sharks that would normally prey on them, and the rivers of Asia spewing vast fountains of plastics and toxins into the sea wiping out the whales food...

 

[HoHun]

Hi,

I'd imagine that when you remove a predator (human whalers) from the environment, the prey (whale) numbers will explode and likely overpopulate. Over time the numbers will come back down to a number the environment can sustain and all will be in balance.

There's actually a useful mathematical model for predator and prey populations, which explains historic data such as these:


Milliers fourrures vendues en environ 90 ans odum 1953 en
Lamiot, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Regards,

Henning (HoHun)

 

[HoHun]

Hi,

And that bit of history likewise applies to whales, At that time, people viewed wildlife populations as inexhaustible resources. There seemed to be so many of them that the thought was, 'Well, we can just take as many as we want, whenever we want, and they'll always be there.' Obviously, that wasn't the case."

I'd say there must have been a bit of purposeful ignorance at work there, too. Jules Verne in his 1873 book "The Fur Country" has one character remarking that to catch beavers, man is penetrating ever deeper into the wilderness, and one day the last beaver will be taken.

So some people at least were aware that some natural resources were finite, and of course Jules Verne had a large readership ...

Regards,

Henning (HoHun)

 

[BlackBat242]

Hi,



I'd say there must have been a bit of purposeful ignorance at work there, too. Jules Verne in his 1873 book "The Fur Country" has one character remarking that to catch beavers, man is penetrating ever deeper into the wilderness, and one day the last beaver will be taken.

So some people at least were aware that some natural resources were finite, and of course Jules Verne had a large readership ...

Regards,

Henning (HoHun)

Don't forget Theodore Roosevelt, who had a go at cattle ranching in South Dakota (and did a bit of hunting at the same time) in the 1880s.

After he returned to the northeast and re-entered New York State and national politics, began pushing that new-fangled idea of "conservation", which included unpopular ideas like limits on hunting and so on.

In a national publication of the time he stated "Today we enjoy a lot of hunting and fishing opportunities, but if we want our children and grandchildren to have the same opportunity we need to work at conserving our living resources."

Here is a very abbreviated overview of his activity: https://www.fws.gov/staff-profile/theodore-roosevelt-1858-1919-conservation-president

U.S. Fish & Wildlife Service

During his very active presidency, Theodore Roosevelt established approximately 230 million acres of public lands between 1901 and 1909, including 150 national forests, the first 55 federal bird reservation and game preserves, 5 national parks, and the first 18 national monuments. In 1905, Roosevelt created the U.S. Forest Service with Gifford Pinchot as its first Chief Forester. Pinchot’s acute eye for habitat helped add critical forests and wilderness areas.

An avid ornithologist, Roosevelt began an ongoing experiment to carve out habitat for his beloved wildlife by creating what would become the National Wildlife Refuge System on March 14, 1903. This early experiment included Pelican Island, Florida, to protect a critical rookery for endangered pelicans; Breton Island, Louisiana, the only refuge that it’s thought Roosevelt visited after his retirement; and National Bison Range, Montana, perhaps our nation’s first attempt at wildlife restoration. Roosevelt’s experiment began with the four-acre Pelican Island Bird Reservation and has since expanded to more than 560 refuges and monuments protecting 850 million acres of lands and waters.

Roosevelt and his most trusted advisor, Pinchot, sought a new term for a new era of environmental action in the early 20th century. They settled on “conservation,” and its popularization is one of his most important legacies. In 1907, Roosevelt declared: “The conservation of natural resources is the fundamental problem. Unless we solve that problem it will avail us little to solve all others.”

 

[HoHun]

Hi,

Don't forget Theodore Roosevelt, who had a go at cattle ranching in South Dakota (and did a bit of hunting at the same time) in the 1880s.

After he returned to the northeast and re-entered New York State and national politics, began pushing that new-fangled idea of "conservation", which included unpopular ideas like limits on hunting and so on.

Thanks a lot, I hadn't been aware of that! Clearly ahead of his time, I'm impressed!

It's sort of a German national trait that regardless of political orientation, we all take it super-seriously if something bad happens to the forests. I recently learned that during the high medieval period, exploitative logging of the German woods had left the country with very little forest, even less forest than we have today. In medieval times, when wood was not only used as the primary building material for just about everything, but it also was the only fuel they had, that was a situation that threatened both wealth and lives of the entire population. It took strict laws, a very protective mindset and a couple of generations to re-forest Germany, and I guess that left our collective mentality with a permanent scar!

Regards,

Henning (HoHun)