Aitutaki's eco-snorkelling trail highlights the frailty of lagoon life, writes Jane Jeffries.
Sitting on the fine white sand, I lower myself into the tepid water, one flipper on, then the other. As I glide off into the clear water, I can already see a large clump of coral surrounded by the tiniest black and white fish.
As I get closer they dart into the branches of the coral tree but don't seem to be perturbed by my presence.
I am in the Aitutaki Lagoon, on the western side of the island in front of the Pacific Resort Hotel and I am about to embark on a self-guided snorkelling tour of the lagoon.
There is growing concern internationally for the fragility of these incredible ecosystems. The Pacific Islands Conservation Initiatives in conjunction with the Pacific Resort Hotel, have established an eco-snorkelling trail to create awareness and educate people about the lagoon environment.
Information is available highlighting the seven different habitats in the lagoon, along with a guide to all the reef creatures, so I can snorkel and discover for myself the wonders of lagoon life.
Close to the shore are the sandy nurseries where juvenile goatfish feed in the mornings and evening.
The previous morning while eating breakfast overlooking the lagoon, I watched ripples on the water made by goatfish swimming in the shallows. It was great to be in the water and know what they look like with their very distinctive "goatees".
A bit further out, but still in waist-deep water, I see the beautiful coral formations, home to many of the young reef fish. The array of colours and creatures living among the coral is vast. They typically stay here until they are mature enough to venture further towards the reef.
As well as the coral and fish in the lagoon, the sea floor is littered with sea cucumbers. They are not the most attractive of reef creatures, looking like giant black slugs but they are harmless and do an important job.
They act as a filtering plant and are often referred to as the "vacuum cleaners of the sea". Sucking up the sand, they filter the unwanted bacteria and algae out of the sand, keeping the lagoon floor clean.
Hovering over one of these slugs I can see what looks like a pile of pellets on the sandy floor. They are the end result of the cleaning process.
After the slug has taken in the sand and cleansed it, out pops a sand pellet. Oh, how useful a slug can be.
As I snorkel further out I see more mature fish including the parrotfish, unicornfish and surgeonfish.
We look for giant clams, native to the Aitutaki Lagoon, but unfortunately don't find any as they are now on the brink of extinction. Although there are still a few left in the lagoon, they are too far from one another to reproduce. They need to be in close proximity for cross fertilisation to occur through the water - and, of course, they don't move.
Before the 1990s the locals described the giant clam as thriving in numbers so great, you could barely walk without stepping on them.
However, over-harvesting has occurred - they are a celebratory centrepiece, much like the Christmas ham - and have been taken from the lagoon in great numbers.
But the good news is there is a successful programme underway to restore the clams to the lagoon. They are a showpiece, weighing up to 200kg and living for 100 years.
They play an important role by filtering the water and providing water clarity, helping prevent toxic algal blooms. The reef is alive and prospering but the giant clams are a reminder of sustainable harvesting. Like all ecosystems, it is delicate.
Getting there: Air New Zealand flies direct from Auckland to the Cook Islands with connections available to Aitutaki through codeshare partner Air Rarotonga.
The writer visited Aitutaki with help from the Pacific Resort Hotel, Aitutaki, and Air Rarotonga.