Entanglement in fishing line and other debris is a threat to cetaceans and other marine life. Unfortunately, not all can be disentangled, but thankfully that wasn't the case for a bottlenose dolphin off Hawaii (the Big Island) last week.
During a manta ray dive, a bottlenose dolphin approached master scuba diver Keller Laros. It had fishing line wrapped around its pectoral fin and line coming out of its mouth. The dolphin cruised up to Laros and rolled over as he started to remove the fishing line while the dolphin patiently waited. Laros was able to free the pectoral fin, remove a fishing hook and cut the line trailing from the mouth before the dolphin swam away.
This is a great example of humans helping marine life, and marine life trusting humans. But the situation could have been prevented if the fishing line wasn't in the water in the first place. When fishing, you can help marine life by disposing of your discarded fishing line in a recycling bin or in the trash, rather than in the ocean. That goes for all marine debris, which can harm marine life through entanglement or ingestion.
The dive and disentanglement were caught on video - you can watch it here.