About 8000 marine species have been ‘described’ (formally identified) in New Zealand’s waters. These include plants, bottom-dwelling (benthic) organisms, fish, marine mammals, birds and other organisms.

In 2000, described species included:

• 61 seabirds
• 41 marine mammals
• 964 fish (of which 108 are endemic)
• 2000 molluscs (snails, shellfish and squid)
• 350 sponges
• 400 echinoderms (kina, starfish and so on)
• 900 species of seaweeds, and
• 700 species of micro-algae

In all, marine species make up almost one-third of New Zealand's total number of described native species. This figure is changing rapidly as on average seven new species are identified each fortnight. Many more species wait to be discovered – marine scientists estimate that as much as 80 per cent of New Zealand's native biodiversity is found in the sea.

Of the marine fish in our Exclusive Economic Zone (EEZ), nearly 100 are rock pool species. Sixty per cent of rock pool species are endemic, and 11 of these species are considered threatened.

Although many marine fish found in New Zealand waters also occur in the waters of other countries, a large number of our benthic species are endemic. New Zealand waters provide critical habitat for some of the migratory species that visit here, particularly marine birds that breed here.

Theme 3 of the New Zealand Biodiversity strategy contains more information about the state of coastal and marine biodiversity.