Bycatch: Dolphins can be accidentally caught and killed in fishing gear. This is especially prevalent in certain fishing methods such as driftnets and purse seines. Driftnets are large mesh nets that are left floating in the water to catch fish. Dolphins, along with other marine animals, can become entangled and trapped in these nets, resulting in their deaths. Purse seines are large nets used by commercial fishing boats. When a school of fish is located, the net is deployed to surround the fish, creating a closed pocket at the bottom of the net. Unfortunately, dolphins swimming near or within the area can be caught in these nets and accidentally killed.
Habitat destruction: Dolphins require healthy habitats such as coral reefs, mangrove forests, and estuaries to survive. Pollution, overfishing, coastal development, and other human activities can lead to the destruction or degradation of these habitats. As their environment is compromised, dolphins may face challenges in finding food and shelter, which can impact their survival and populations.
Pollution: Pollution from sources like industrial waste, oil spills, plastics, and fertilizers can contaminate marine waters, negatively impacting dolphin health and survival. Chemicals and toxins from pollutants can accumulate in the dolphins' bodies, causing various health issues and weakening their immune systems. Some pollutants can disrupt dolphin reproduction and affect the survival of calves.
Aquariums/Captivity: While many countries now have regulations and protections for dolphins regarding their capture and treatment in captivity, some facilities still continue to take dolphins from the wild for public display and performances, such as marine parks, aquariums, or travelling shows. Dolphins are highly social and intelligent creatures, and capturing and placing them in confined environments can have negative long-term effects on their well-being.
Intentional killing: In some instances, dolphins have been intentionally killed due to human conflict and negative perceptions. In regions where dolphins may compete with fishermen's catches, they may be targeted and killed as a perceived threat to livelihoods or in acts of revenge. Moreover, historical misunderstandings and negative portrayal of dolphins in media have led to instances of people killing them out of fear, ignorance, or perceived competition for fish stocks.