Question

The Sunken Valley off the south-west coast of Tasmania, and coastal Fiordland on the south-west coast of Aotearoa New Zealand share what quality?

Answer 1

Normally deep-sea marine life lives within 40 m (131 ft) of the surface
Tannin rich waters running off from lush forest form an up to 6m (19.7 ft) deep dark layer which does not mix with the salt sea water and which cuts out most of the light to the sea bed. This creates what is effectively a deep-sea environment in the relative shallows.