Community groups and scientists have begun ‘Kelp Gardening’ in the Hauraki Gulf. The activity involves removing kina (se urchins) from rocky reefs to allow the kelp to regrow. It gives divers and snorkelers something to do on a reef (where they no longer have fish to hunt) and fits nicely with New Zealand pest management ethos (suppression).
However kina are not a pest, their numbers are artificially inflated by overfishing. See diagram of mine from the State of the Gulf report below.
Kelp gardening differs wildly from other active restoration techniques as it replaces a natural function with a human intervention. The activity may have a place in the creation of a marine protected area but it is not a smart long term reef management technique because it treats the symptom not the cause of a sick reef.
So why are well respected scientists and well intentioned volunteers doing it? I really think it’s just because calls for marine protection have fallen on deaf ears, and some people are so desperate to fix things they will try anything.
UPDATE: 11 March 2021: In a public seminar today Dr Nick Shears who is an expert on kina barrens in New Zealand said “kina removal can be incorporated into restoration / management but we want to make it clear it is not the answer on its own!“