Just a little over a year ago, I was out on a survey dive with my boss at my old workplace at Lankayan Island. I can't remember what it was we were supposed to be looking for, but as I was adjusting my mask underwater, I nearly finned right into a ghost net.
You might be wondering, what's a "ghost net"? Ghost nets are fishing nets that have been left or lost in the sea by fishermen. These nets, often nearly invisible in the dim light, can be left tangled on a rocky reef or drifting in the open sea. They can entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other marine creatures, including the occasional human diver. :-/ (Source: here)
Upon finding the ghost net, we went along the line to find out how long/big it was. It took us nearly 40 minutes (the average time for a dive) to go from one end to the other and along the way, I noted at least five turtle skeletons, presumably from when they got caught in the net and drowned.
The damage to the reef was also quite substantial. We found many overturned corals, probably due to the movement of the net during storms.
So my boss and I went back to the island to recruit some volunteers (most of whom were divers in our dive group that week) and armed with scissors and knifes, we went back to the spot to try get as much of the net out as possible.
It took us four dives over a period of two days to clear the net. There were some left over that was hanging over a cliff at the edge of the reef. It was pretty deep at that part so we didn't continue. The waves were also pretty strong by then so by the last snip, most of the net drifted off into the open ocean. None of us could quite hang on to it. :-/
By the time we were done, most of the holiday for the other divers was over too. I remembered feeling a bit sorry for them because the work was very tiring and they didn't get to explore much of the reefs around the island. However, it was indeed a good opportunity to spread awareness on the effects of destructive fishing methods. All of them left with a sense of accomplishment and of course, free beer that night helped everyone make friends with each other too! ;)
A few days after, a tsunami struck Japan. But that's another story... :)