(CBS 8) - You probably don't think twice about how the seafood you're eating for dinner was caught, but one man is on a mission to make sure you know what was left behind in trying to catch it.

It's an out of site, out mind problem for those of us who don't dive. Fishing nets laying on the bottom of the ocean floor -- a rarely seen issue that Kurt Lieber from Ocean Defenders Alliance wants people to know about.

Because they're down on the bottom sometimes it doesn't look like they're killing anything, but if you look next to it there's a healthy ecosystem, these nets smother the reef and prevent the anemone feather duster gorgonian from growing," Kurt said.

The nets he's talking about are left behind by fishing companies.

"They just chop the line and let it sit there, and it's legal to do that," he said.

Lieber claims these nets then continue to catch fish and other marine life inadvertently, killing them.

These bodies decompose within two to five days, so you really have no feel for how many animals are dying in these things," Kurt said.

The retrieval process is slow and the silt stirred up makes it difficult work. He says it's time fishing companies take on more responsibility.

"They need to contribute more to the oceans they can't just keep taking and taking," he said.

Lieber says a system needs to be in place to tag fishing companies' equipment and make the companies accountable when they lose it in the ocean.