Slugs killing dogs in New Zealand

October 28, 2009
From: Bill Rudman

A couple of months ago I saw reports from New Zealand of dogs in Auckland being killed by eating slugs which had washed up on beaches. At the same time this was linked with some fish kills, dead dolphins and penguins to suggest a major ecological catastrophe. The slug story was difficult to investigate because the slugs were not identified.

Since then investigators have identified the slug as Pleurobranchaea maculata and identified the toxin to tetrodotoxin, which was initially thought to be produced by puffer fish, but is now known to have a bacterial origin and has been reported in a wide variety of marine animals including the blue-ringed octopus Hapalochlaena. What is not known is whether the tetrodotoxin is always present in Pleurobranchaea or whether it is a chance result of these carnivores eating an affected carcase. However, since a number of specimens of Pleurobranchaea contained the toxin, finding the source of the toxin may be more complicated than just assuming they all fed on one carcase. If anyone has similar records of toxic Pleurobranchaea from elsewhere in the world they would be of interest.

The other example it brings to mind is the regular occurrence of toxic sea hares washing up on the beaches of Western Australia and killing dogs. Perhaps tetrodotoxin is the cause there as well [see messages on Aplysia gigantea page].

I have included two links below to reports in the NZ Herald and a pdf of the scientific report prepared by the Cawthron Institute

Best wishes

Rudman, W.B., 2009 (Oct 28) Slugs killing dogs in New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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