What are some common threats to marine mammals?
Unfortunately, one of the characteristics marine mammals share is that most are, or have been, exploited by humans. Whales, sea otters, sea cows, and seals have been historically overexploited, which has resulted in the extinction of some species (e.g. Stellar sea cow, Caribbean monk seal, and the Atlantic gray whale) and the endangered status of many. Though there are laws that protect marine mammals, not all countries abide by these laws. So, the direct harvesting of whales, seals, walruses, dugongs, and dolphins still occurs today in various places throughout the world. Another threat to marine mammals is entanglement in fishing gear and nets. Many marine mammal species are accidentally caught in nets used by fishermen. This is called “bycatch”, which is the non-target portion of the catch. Bycatch includes not only marine mammals but other species of fish, invertebrates, reptiles, and even birds and is a very wasteful practice. Passive, or discarded, gear and trash can also cause a
