Pollution and Pathogens
Pollution comes in many forms in the marine environment, and therefore poses many different threats.
A green turtle attempting to nest on a heavily littered beach. Marine pollution can lead to death or a severe impairment of sea turtle behaviour. Plastic bags, balloons, polystyrene and other non-degradable discards found near the surface are often consumed by sea turtles mistaking them as food.
This can result in choking, suffocation or blockage of the digestive system leading to starvation. Having reached the open ocean, young turtles rely on the accumulation of food on ocean driftlines. Unfortunately, non-degradable marine pollution also accumulates on these driftlines, increasing the chances of accidental consumption by juveniles and adults alike.
Other discards, particularly meshed items such as abandoned fishing gear, sacks, or plastic netting pose a threat to turtles through entanglement. Entanglement can lead to death by drowning, or restrict the migratory, feeding and reproductive behaviour of turtles. The potential of all of these is a reduction in the size of the next generation of sea turtles.
A green turtle suffering from fibropapillomatosis. Chemical pollution has several negative effects on the survivorship of turtles. Coastal pollution from fertilizers, pesticides, sewage and other industrial, agricultural and urban runoff can lead to the death of aquatic animal and plant life, removing food that sea turtles rely on when closer to shore.
Furthermore, chemical pollution can weaken the immune systems of turtles, making them more susceptible to disease. A disease currently responsible for the death of many sea turtles, known as fibropapillomatosis, is thought to be linked to pollution in coastal waters.