• Problem Many of the world’s marine biodiversity hotspots have been over fished. These hotspots are seldom recognised as such due to a lack of taxonomic information. • Methods Surveys revealed that an area of seafloor approximating 20 x 10 square km is the most diverse so far known for the New Zealand region, with high levels of local endemism. • Lessons Only detailed, authoritative taxonomy allowed for the recognition of this area as New Zealand's marine-biodiversity hotspot, and thus for the protection of the area from fishing activities…and save it as a spawning ground.