Nine gray whales landed on the California coast within the past two months. Unusually large numbers make scientists anxious, headache to find the cause.
"This is very unusual. Normally, we see only one to three gray whales a year. But the number is now three, but in less than two months," said Padraig Duignan. head of pathological research at the Mammal Center in Sausalito, California, sharing with the Washington Post.
Four of the nine whales brought to the study at the center were identified as being caused by malnutrition. The other four died from collisions with boats, and the other one, found on April 30, still cannot determine the cause.
The latest gray elephants found on May 6 at Ocean Beach in San Francisco, the whale is more likely to die after colliding with boats.
"It seems that the trauma caused by the great force has claimed its life , " Duignan said after performing an autopsy on May 7. The expert also said that the fish was severely malnourished, when its outer whale fat layer was exhausted and the amount of fat inside the body was almost nonexistent. This is completely unlike the usual status of a gray whale at this time of year.
The Center for Marine Mammals has collaborated with other organizations such as the National Oceanic and Atmospheric Administration, the California Academy of Sciences and other scientists in this part of the state to follow the lives of Whales and other animals in the Atlantic.
Biologists observe a worrying trend as more and more gray whales are malnourished, dead and drifted to the coast this year. In Washington state in the north, 13 bodies of gray whales have drifted to the coast since April, mainly due to starvation. Currently, the number of dead gray whales washed up the US west coast earlier this year to 46, compared with 25 individuals in the entire 2018 year.
Gray whales migrated south in the winter to breed off the Mexican state of Baja California, before returning to Alaska in the spring. They travel through California waters from December to January each year, and again from April to May. This round-trip journey extends to 11,000 miles (17,700km) and is the largest annual migration in number of whales.
Their staple food is small invertebrates, which mostly take place in the summer in Alaska.
But this year, Duignan said, when the gray whales went to the San Francisco Bay Area, they seemed to have "run out of energy." Scientists found that they hunted in this area, which is extremely unusual and proves that they are hungry.
"The assumption is that last summer, when these whales were in Alaska, they did not have food to store enough energy for the migration season," said Moe Flannery, an expert on birds and Mammals at the California Academy of Sciences, said.
In Baja California, scientists also observed that gray whales appear later, reproduce less and their numbers also decrease.
Although the number of gray whales in the wild is quite stable, California's changing ocean climate and warming in Alaska are creating pressure on the animal. According to statistics, there are about 26,000 gray whales in the wild, they only live in the Atlantic Ocean. There was a time when this species stood on the brink of extinction in the early 20th century.
"Alaska has experienced the highest temperature increase compared to other states in the US", the National Oceanic and Atmospheric Administration said that identifying the state's marine ecosystem "is very vulnerable to gas change. post ".
On May 6, the day when the latest gray whale was discovered at California Beach, the United Nations published a shocking report saying about 1 million animals are on the verge of extinction due to activity. human movement
"The health of the ecosystem that we and other species rely on is declining faster than ever," said Robert Watson, UN committee chairman, in a statement attached to the report.
Mr. Duignan said that more research would be needed to clarify the cause of gray whales' death, but he did not object to the fact that humans play a certain role in making this situation happen.
"Whales who die due to stabbing have a direct cause from humans. Other children are malnourished, we don't know why that is so, but it is very likely that the effects from global warming are demand is causing an impact, " Duignan said.