Off the mainland coast of New Zealand, shelf-edge instability is enhanced in some locations by cold seeps of methane-rich fluids that likewise support chemosynthetic faunas and carbonate concretions. Dominant animals are tube worms of the family Siboglinidae and bivalves of families Vesicomyidae and Mytilidae ("Bathymodiolus"). Many of its species appear to be endemic. Deep bottom trawling has severely damaged cold seep communities and those ecosystems are threatened. Depths down to 2,000 m including cold seeps belongs among as-yet-unmapped topographic and chemical complexity of habitats. The scale of new-species discovery in these poorly studied or unexplored ecosystems is likely to be high.