Scientists believe the sex life of toxic sea slugs may hold the key to what they call a toxic invasion of Auckland beaches.
Five dogs died and about 10 more became ill last year after eating the slugs. Recent sightings have prompted further health warnings region-wide.
Massey University is now launching a three-year project trying to find out how the sea slugs migrate and mutate, and if their population is increasing.
Professor Paul Rainey says they want to know whether the slugs are having sex with their neighbours or what he calls out-of-towners.
He says they will compare concentrations of the lethal toxin in different sea slug populations in the Hauraki Gulf and other New Zealand coastal waters.