‘Invasive’ species disappearing rapidly on Catalina Island

Like its iconic palm trees, California’s bison were brought to the West by Hollywood producers for Western filming 100 years ago—but now catalina island they are dying.

What began as a herd of 14 bison, sent in the 1925s”vanishing american“Their numbers soon exploded. At one time, thousands of them roamed the island off the coast of Southern California, sfgate report,

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

In the early 2000s, bus and jeep tours of Catalina’s interior generated 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.

Scientists said the mammals’ very existence threatens the entire ecosystem of Catalina Island.

However, the bison – which were named the official national mammal in 2006 – have stopped reproducing and their numbers have declined rapidly.

Efforts to reduce the bison population began in the 1970s. catalina islandMany animals have been removed to the mainland.

In recent years more aggressive tactics have been adopted to reduce the herd to a more manageable size, including birth control vaccines given to females in an effort to stabilize the population at around 150.

It was thought that the vaccine’s effectiveness would change over time — but it didn’t, SFGate reports.

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

Scientists do not expect the last bison on Catalina Island to disappear for another 30 years.