What kinds of marine debris?

The graph below shows that trawl netting is a common material which entangles seals. It is made from a very strong form of plastic known as polypropylene.

Fishing line (called monofilament line) is also a big problem. While the frequency of trawl net seen on seals at Seal Rocks has decreased in recent years, recently more seals have been seen entangled in fishing line.

Other materials that probably come from ships are ropes, twine and chord. Box straps are loops of plastic that hold cardboard boxes together. Most box straps that are in the ocean come from around boxes that hold bait used for commercial fishing.

Supermarket plastic bags can also get caught around seals. The bags might get washed or blown from the beaches. Most likely, though, plastic bags in the sea come out of boats (where they were used to hold fishing bait, lunches etc).

Ribbon around seals’ necks is often brightly coloured party ribbon. This often has a deflated balloon attached.