A decade of research into the Rena disaster has shown how over-fishing impacts reefs

It's 10 years today since the Rena hit Otaiti Astrolabe Reef off the Bay of Plenty Coast.

Waikato University Marine Ecologist Dr Phil Ross has been studying the area since then.

He says the reef was locked down for five years - and snapper and crayfish populations soared, but plummeted when the reef re-opened.