Bye bye, bison: ‘Invasive’ species dying off rapidly on Catalina Island

Much like its iconic palm trees, California’s bison were brought out west 100 years ago by Hollywood producers filming westerns — but now on Catalina Island they’re dying off.

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

And they were also a boon to the island’s tourism.

As of the early 2000s, bus and Jeep tours of the interior parts of Catalina brought in more than $4.2 million in annual ticket sales, according to a report.

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

The mammals’ very existence threatens Catalina Island’s entire ecosystem, scientists said.

The bison — designated the official national mammal in 2006 — have stopped reproducing, however, and their numbers have shrunk fast.

Efforts began back in the 1970s to reduce the bison population on Catalina Island, with the many of the animals being removed to the mainland.

More aggressive tactics have been taken in recent years to reduce the herd to a more manageable size, including birth control vaccines administered to the females in an effort to stabilize the population at about 150 of them.

It was thought the vaccine effects would reverse over time — but that hasn’t happened, SFGate reported.

The last bison was born on Catalina Island in 2013. Today, about 80 remain.

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