‘Invasive’ Species Are Rapidly Disappearing on Catalina Island

Like its iconic palm trees, California bison were brought to the West 100 years ago by Hollywood producers filming westerns. Today, on Catalina Island, they are dying.

What started as a herd of 14 bison, shipped for 1925’s “The Vanishing American,” their numbers quickly exploded. At one time, thousands of them roamed the island off the coast of Southern California, SFGate reports.

And they also represented a boon for tourism on the island.

In the early 2000s, bus and jeep tours of the Catalina interior brought in more than $4.2 million in annual ticket sales, according to one report.

But these bison are also an invasive species, not native to the Golden State.

The very existence of these mammals threatens Catalina Island’s entire ecosystem, scientists say.

Bison – designated an official national mammal in 2006 – however, stopped breeding and their numbers rapidly declined.

Efforts began in the 1970s to reduce the bison population on Catalina Island, with most of the animals translocated to the mainland.

More aggressive tactics have been adopted in recent years to reduce the herd to a more manageable size, including contraceptive vaccines administered to females in an effort to stabilize the population at around 150 head.

It was thought that the effects of the vaccine would reverse over time – but that did not happen, SFGate reported.

The last bison was born on Catalina Island in 2013. Today there are about 80 left.

Scientists don’t expect the last bison on Catalina Island to die for another 30 years.