As if mankind hasn't done enough damage to the sea yet, the past seems determined to finish the job. "Ghost nets" have become an increasing problem in the Atlantic Ocean, destroying fish and other marine life.

"Ghost nets" are fishing nets that were discarded in the ocean. Left unattended, these nets continue to catch fish, some for years on end. The nets effectively become fish graveyards, and so they are aptly named.

The nets have caused a devastating loss of marine life. Deepwater shark population, for instance, has fallen by 20% in the last 10 years. Aside from the growing environmental concern these nets present, they have also become a problem to fisheries.

To clean the ocean of these nets, the Irish Sea Fisheries Board will start Operation Deepclean. The operation hopes to retrieve the thousands of kilometers of lost and abandoned nets in the Atlantic over the years.