If you've clambered along rocky coastlines where ulua anglers go, you've seen tangles of bluish white discarded fishing line.

If you've snorkeled along popular angling shores, you've seen monofilament snagged on coral heads, with bits of it drifting sinuously in the current.

At the high water line, you may have seen tangles of pale nylon netting, twisted up with chunks of rope and swatches of cargo and trawl netting.

Monofilament is a very specific kind of fishing line. It's often bluish or greenish, and comes as a single strand, as the name implies — not woven or twisted like rope or many kinds of cord. It is a remarkably effective bit of fishing gear, nearly invisible in the water. It's very strong, and it survives a long time in the environment.

You've seen it, but if you pick it up, what to do with it?

Rodney Izuo, of the fishing supplies wholesaler Izuo Brothers, made contact some years ago with a Mainland firm that recycles nylon line, Berkley Pure Fishing. On learning of the Iowa sportfishing tackle firm's environmental protection program, Izuo began providing his fishing supply retailer clients with the firm's postage-paid monofilament recycling boxes.

Hawai'i companies on four islands now have boxes where you can drop off old fishing line for recycling. They are Brian's Fishing Supplies, Hanapaa Hawaii, Lihu'e Fishing Supply, Maui Sporting Goods, McCully Bicycle, Melton International Kona, New Maui Fishing Supplies, Pacific Ocean Producers, Roy's Fishing Supply, S. Tokunaga Store and Waipahu Bicycle.

Izuo said much of the recycled material that ends up in the recycling boxes comes from the line on old fishing reels when anglers strip it off at the fishing supply store to replace it with new line.

The recycling program ships filled boxes of line to Pure Fishing, which cleans it and then melts it and recycles it into — among other things — plastic shapes that can be sunk to serve as fish habitat.

"It's just a great program," Izuo said.

A good resource on the dangers of monofilament, and how and why to recycle it, is online at the Florida Fish and Wildlife Conservation Commission Web site, MyFWC.com/mrrp/faq.htm.

If for some reason you can't get to one of the places that accepts the line, the Web site suggests you cut monofilament into short lengths before tossing it into the trash — so it can't entangle anything even if it gets back into the environment.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.