Rena Oil Spill: Marine Mammal & Fish Impacts

New Zealand fur seals, bottlenose dolphins, orcas, beaked whales and migratory baleen whales can all be found in Bay of Plenty waters.

Like seabirds, these marine mammals will not necessarily avoid the oil spill. They’ll continue to swim and feed in or near the polluted water. This may cause them to suffer from some of the ailments listed below -

  • LOSS OF INSULATION Oil clogs seals’ fur and strips their natural insulation capacity.
  • WEIGHT LOSS Marine mammals may suffer weight loss as oil hinders their ability to feed. For example, oil can cling to the blue whale’s baleen teeth.
  • DROWNING Seal pups may drown if the oil sticks their flippers to their bodies and hampers their ability to swim.
  • EASY PREY Inability to swim effectively may make marine mammals, such as seal pups, more vulnerable to predation.
  • INTERNAL DAMAGE Oil ingested during feeding and grooming can cause ulcers or bleeding in the stomach.
  • POISONING Secondary organ dysfunction may occur in some species when oil is accidentally ingested during feeding or grooming.
  • REDUCED BREEDING Affected marine mammals may desist from breeding or change their normal breeding behaviour, resulting in further population decline.
  • RESPIRATORY DAMAGE Oil or oil vapour may be inhaled as marine mammals surface to breathe, damaging airways and impairing their ability to breathe.
  • EXTERNAL IRRITATIONS Continuous exposure may cause skin lesions and eye irritations.
  • STRESS Continual oil exposure and behavioural changes will elevate stress levels.

Coastal and reef fish will also suffer from the oil spill, especially as some species will mistake oil for food. Eggs, larvae and young fish will be particularly vulnerable. They may be less able to cope with external contamination and their immune systems will be less developed to cope with toxicological effects.