Climate change will deplete the fish stocks that feed on Arctic predators such as ringed seals, forcing them to go after smaller, less nutritious prey, a new study warns.
The study, prepared by researchers at the University of British Columbia, suggests that changes in both fish numbers and size will accelerate in Canada’s Hudson Bay by 2025.
Cod stocks will decline by 18 to 35 percent and the Pacific sand lance will decline by 45 to 82 percent. The body size of that species will also shrink, meaning seals they find will not have such a nutritious meal.
Climate change will reduce certain fish that seals feed, causing them to eat less satisfying fish
The size and population of fish in Hudson Bay – such as Arctic cod – will accelerate by 2025 and population figures could fall by 50%
Cod will decrease in size between 18-35% and Pacific sand lance will decrease between 45-82%
They estimate that if the atmosphere continues to be affected by greenhouse gases, such as carbon dioxide and methane, all species of fish in the study will shrink in size.
This decrease in body size, along with a shift from the energy- and fat-rich Arctic cod to smaller forage fish, could lead seals to feed more on ‘junk food’ with unknown demographic consequences, but perhaps also with reduced energy reserves (stored as blubber),’ the authors wrote in the study.
All fish species decreased in body size, according to the model, but there was a 29 percent increase in total prey biomass, meaning smaller fish, such as capelin and sand lance, were more common.
“It takes energy to forage,” the study’s lead author, UBC student Katie Florko, said in a statement. pronunciation.
“Does this mean that the seals need more energy to catch a greater number of these smaller fish for the same amount of energy as catching a larger fish?”
Florko continues, “It’s no different from how the burgers in fast food restaurants seem to get smaller and smaller every year, and you’re getting less bang for your buck.”
With Arctic waters warming due to climate change, cod will migrate north and decrease in numbers, the researchers said.
It is unclear what the consequences would be if you ate less satisfying fish and no cod (pictured)
All fish species decreased in body size, according to the model, but there was a 29 percent increase in total prey biomass, meaning smaller fish, such as capelin and sand lance (pictured), are more common.
As Arctic waters warm due to climate change, cod will move north and decrease in numbers, the researchers said.
The findings are not unexpected. Several other recent studies have suggested that fish will get smaller as the world gets warmer because they need to increase their metabolism and need more oxygen to maintain their bodily functions.
A study published in February looked at fish size and seafloor temperature over the past 30 years and concluded that adult fish sizes, including cod, haddock and whiting, are shrinking.
In August, a separate study suggested that other fish, such as sardines, sardines and herring, are shrinking and facing extinction due to climate change.
Last month, a United Nations report said the planet will warm by 2.7 degrees Fahrenheit by 2040, a decade earlier than predicted.
Since larger fish can have greater energy reserves compared to smaller fish, size reduction will reduce the distances fish can travel and limit their ability to seek more suitable environments as climate changes.
For other animals, the situation is more complex, Florko noted.
Beluga whales feast on capelin in the summer, but eat Arctic cod in the fall to store body fat.
“We’ve never seen such a drastic change so quickly,” said Travis Tai, a co-author of the study.
“We’re rolling the dice and we don’t know exactly what’s going to happen.
“If we have dramatic shifts in food web structures, we can expect big changes not only in how species like ringed seals use the oceans, but also in how humans use the oceans.”
The study was published last month in the journal Ecology Letters.
CRIMING SPECIES: EXPERTS PREDICT GLOBAL WARMING WILL CRIMPING OF CREATURES
A recent study in Canada found that the region’s beetles have shrunk over the past century.
By looking at eight species of beetle and measuring the animals of the past and present, they found that some beetles adapted to smaller body sizes.
The data also showed that the larger beetles shrink, but the smaller ones do not.
About 50 million years ago, the earth warmed by three degrees Celsius and as a result the animal species shrank by 14 percent.
Another warming event about 55 million years ago — called the Paleocene-Eocene Thermal Maximum (PETM) — warmed the Earth to eight degrees Celsius (14.4 °F).
In this case, the animal species of that time have shrunk by up to a third.
Woolly mammoths suffered from a warming climate, shrinking habitat and increased hunting by a growing early human population that drove them to extinction – along with many large animals
Shrinking in body size can be seen from several global warming events.
As global temperatures continue to rise, the average size of most animals is expected to decline.
In addition to global warming, the world has seen a dramatic decline in the number of large animals.
So-called ‘megafauna’ are large animals that are going extinct. With long life spans and relatively small populations, they are less able to adapt to rapid changes than smaller animals that reproduce more often.
Often hunted for trophies or for food, large animals such as the mastadon, mammoths and the western black rhinoceros, which were declared extinct in 2011, have been hunted to extinction.