When a feminine grownup sea lion got here ashore in San Luis Obispo Cou, annty in central California not too long ago, responders instantly knew one thing wasn’t proper.
She was skinny and underweight, swayed her head forwards and backwards and didn’t flee as folks approached, stated Dr. Cara Field, medical director on the Marine Mammal Center in Sausalito.
“All of those things tell us there’s something wrong, but we didn’t know what it could be until we got her here,” Field stated.
Once the sea lion was sedated and intubated in a quarantine cell on the middle’s grounds for an ultrasound, extra worrying indicators appeared.
“That’s a very, very bad kidney,” Field stated, leaning over the sea lion whereas wanting on the ultrasound display screen. “With cancer, what we often see is the cancer has metastasized.”
The sea lion inspected on this present day was euthanized, a standard ending for California sea lions introduced right here for what has develop into a frequent and untreatable prognosis – urogenital carcinoma.
It has wreaked havoc on these marine mammals.
According to a research revealed in December in Frontiers in Marine Science, nearly 25 p.c of grownup California sea lions find yourself with this most cancers, the best prevalence of most cancers in any mammal, together with people.
“This is extraordinary and really quite awful,” Field stated. “This is an unprecedented rate of cancer in wildlife.”
The research discovered two main culprits behind the excessive most cancers charges – long-banned chemical pesticides comparable to DDTs and polychlorinated biphenyls (PCBs) discovered within the sea lions’ blubber tissue and the presence of a cancer-causing herpes virus generally known as Otarine herpes virus (OtHV-1).
“Very few animals that had cancer did not have the virus,” stated Dr. Padraig Duignan, director of pathology on the heart and a co-author of the research. “But then when you looked at the levels of chemicals in their blubber and you factor that in, the presence of the chemicals and the level of them increased the probability of cancer anywhere between 30 percent and 80 percent higher.”
The research included samples from practically 400 sea lions over 20 years. Both Field and Duignan usually see these sufferers, as Field typically oversees admission exams and ultrasounds whereas Duignan carries out the necropsies.
In the necropsies, scientists conduct a full dissection. They additionally search for metastasis that unfold to different components of the physique, together with the lymph nodes, stomach cavity and chest cavity.
Duignan pointed to the mammals’ breeding grounds close to the Channel Islands in southern California, the place poisonous chemical compounds had been dumped for years.
A Los Angeles Times investigation final yr discovered “thousands of barrels of acid sludge” laced with DDT dumped close to Santa Catalina Island within the years after World War Two. Sediment samples confirmed DDT ranges 40 occasions greater than the quantity detected at a close-by EPA-designed hazardous waste website.
DDT was banned within the United States within the Nineteen Seventies and PCBs had been outlawed in 1979 after being linked to most cancers and different well being issues.
But the chemical compounds made their manner by the meals chain and finally into the blubber of sea lions.
Both Field and Duignan consider that the sea lions’ most cancers gives a stark warning for people.
Field stated, “the strong association with the herpes virus and pollutants in the environment is a huge warning to us to pay attention to what’s happening in the oceans.”
“Knowing that there’s this presence… that makes you want to take action to improve our environment, not just for the sea lions but for ourselves as well,” Field stated.