Greenpeace describes half-abandoned "pirate fishing" boats. Pirate fishing is their name for "illegal, unreported and unregulated" fishing, which sounds like something no one other than Greenpeace could get worked up over. But picture rusting ships, no lifeboats or safety equipment, broken down, leaking junk into ocean, fishing for any kind of product that's valuable no matter whether it's endangered or whether a certain area is overfished or polluted for that matter. Then picture the desperate crew who would get roped into that kind of lousy job, and imagine how concerned the boat owners are going to be for health or safety or human rights of their crew.
Worse than all that, they leave crew members on "zombie ships" -- which is another catchy name for anchoring a ship far offshore while the captain tries to gather a new crew or supplies or maybe capital. Some of these guys claim they haven't set foot on land for two years. If the ship docks too often, the mistreated crew can escape, or port authorities can enforce regulations. They unload their catch and even refuel at sea, all the better to avoid inspections and laws.
"Here's the thing - these ships seldom, or ever, visit a port. They're re-supplied, refuelled, re-crewed and transhipped (unloaded) at sea. The owners and crews don't seem to do any basic maintenance, apart from keeping the engine and winches running. There's no glass in the portholes, and the masts are a mess of useless wiring. These floating deathtraps don't carry any proper safety gear - on one boat, I saw the half-barrel case of an inflatable liferaft being used to store a net."