The report of a Russian mini submarine snagged on the ocean floor last week by fishing net cables ignited a special kind of fear in the small corps of folks who voyage in the deep sea.

"We're deeply concerned about that. Every time we're in our subs, we're acutely aware of old nets, ropes and cables. We see them all the time," said geologist John Wiltshire, acting director of the University of Hawai'i's Hawai'i Undersea Research Laboratory. The lab operates two manned deep submersible craft, the Pisces IV and Pisces V.

The problem of marine debris is a significant one on the ocean's surface, and in an age of floating plastic, that's where a lot of it shows up. Drifting nets, ropes, bottle caps, jugs and all the rest snag coral heads and rip them up in high surf, entrap fish and such marine animals as seals and turtles, choke seabirds and much more.

The Russian sub became entangled in a fishing net in 600 feet of water off the Kamchatka coast. Russian officials had said the sub was participating in a combat training exercise when it got caught on an underwater antenna assembly that is part of a coastal monitoring system.

But British Royal Navy Commander Ian Riches yesterday told the Associated Press that the vessel had become tangled in fishing nets, as had been originally reported.

In Hawaiian waters, there is no shortage of chunks of trawl net and cargo netting wafting from the bottom, and of cables — some dating back half a century.

"After the second world war, the Navy dumped all kinds of stuff, like spools of steel cable. We really have to watch out for that stuff," Wiltshire said.

There are particular dangers in busy fishing areas. Wiltshire said illegal dredging for precious corals in the Northwestern Hawaiian Islands — generally done by foreign ships — is a special concern. Many of the trawl nets catch on features on the ocean floor and tear free; they are anchored to the bottom, but the plastic netting is buoyant and can sway in the currents like a giant trap for anything that comes along.

It all comes of treating the ocean as if it were a bottomless pit — a place where you could dump or lose things and never expect to see them again. But they are still there.

Marine archaeologists, biologists in submarines and even anglers find them. Bottomfisherman Greg Holzman, of Kaua'i, said he often accidentally hooks lost longline gear that continues to haunt the depths.