Water Pollution

An increasing threat to wild dolphins is the contamination of their natural habitat from marine debris such as plastic bags and other forms of litter, sewage spills, agricultural runoffs and dumping of oil, chemicals and heavy metals.

Massive amounts of such waste products enter the oceans everyday. Some pose as physical hazards, whereby dolphins accidentally consume them mistaking them as food, hence causing internal injuries such as intestinal blockage, or suffer from choking. Plastics, being non-biodegradable, stay and never go away once they enter the oceans. The amount of waste in the ocean known as ‘The Great Pacific Garbage Patch’, twice the size of Texas, is 90% made of up plastics. Dolphins also face the issue of entanglement in such marine debris.

Sewage, oil, chemicals and heavy metal pollution weakens the immune system of dolphins. Research has shown that these pollutants in the water are the reason for the cancerous tumours found in dolphins. Persistent Organic Pollutants (POPs) such as pesticides and other industrial chemicals are major hazards. POPs are linked to immune system suppression and reproductive failure, and are found in high levels in the dead bodies of dolphins all over the world. With suppressed immune system, dolphins may succumb easily to bacterial and viral infections.

In the ecosystem, dolphins are at the top of the food chain, hence are at higher risks of contamination. They feed on polluted plants and smaller fish, and since the levels of concentration of contamination increases as it moves up the food chain, dolphins inevitably suffer a greater impact of contamination.

We have been dumping these toxins into the oceans for decades, assuming that it would always be vast enough to absorb them all. However, the oceans are getting more and more saturated. The garbage we create everyday mostly ends up in the oceans, possibly endangering all forms of marine life, including dolphins.