SAN FRANCISCO (CBS SF) – The fate of two sea lions entangled in ocean trash who have been spotted at San Francisco’s Pier 39 this month is all too common, wildlife rescuers said Friday.

The two sea lions, a juvenile weighing roughly 200 pounds, and an older one weighing around 400 pounds, both have strands of plastic or wire wrapped around their necks.

The two animals remain healthy so far and have eluded four attempts at capture by would-be rescuers, but face potential injury or death if the snares are not removed, Marine Mammal Center spokesman Jim Oswald said Friday.

Oswald said that while some animals live for a long time with entanglements, the trash wrapped around the neck can prevent them from foraging, causing them to lose weight and making them more vulnerable to disease and predators.

In addition, as they grow, the strands can cut deeply into their skin.

He said rescuers will make further attempts to rescue the animals, but need to be careful to allow them to rest and to not make the entanglements tighter.

While these sea lions are drawing attention because of their highly visible location at a site popular with tourists, Oswald said such entanglements are extremely common. Common hazards include fishing lines and fishing nets made of plastic.

“This is something we see all too often, especially down in the Monterey area, where there are all kinds of animals entangled in ocean trash,” Oswald said. “Ocean trash is a huge problem.”

An exhibit of ocean trash sculptures at the Marine Mammal Center in Sausalito right now highlights the global problem, Oswald said.

“If you have fishing line or fishing net, don’t dispose of it in the ocean,” Oswald said. “Cut it up and dispose of it properly.”

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)