The kingdom’s corals – How are Cambodia’s reefs doing?

As we surrendered to the ocean current, our team of eight divers gently glided over the sprawling corals and sponges. Christmas tree worms of every colour popped out from the rocks. Giant clams as big as our heads blinked their fluorescent lips. Hundreds of vibrant fish eyed us, and our trails of bubbles, with apprehension.

Fauna & Flora International (FFI), accompanied by partners from Kuda Divers and the Song Saa Foundation, recently embarked on a ten-day reef expedition of Cambodia’s Koh Rong Archipelago to assess whether reef health has changed since the archipelago was designated as a Marine Protected Area in 2016. The expedition included comprehensive surveys of corals, fish and invertebrates around Koh Rong and Koh Rong Sanloem – both rapidly developing as tourist hotspots. We also ventured across open ocean to the outer island gems of Koh Tang and Koh Prins.

Christmas tree worms get their unique appearance by being adapted to filter feed for microorganisms, and hide themselves when threatened. Credit: Roger Bruget

Preliminary results reveal a mixture of promise and cause for concern. Coral cover was high at many sites, and the flourishing outer island reefs could go toe-to-toe with world famous dive sites in Indonesia or the Maldives. Corals around Koh Rong also appear to be in good health, with minimal evidence of bleaching impacts. However, there was a great contrast between the marine environment of the remote outer islands and those on heavily inhabited and visited islands. Abandoned fishing gear – which the team spent some time cutting away – was widespread in the archipelago, smothering many magnificent corals. Household waste such as cans and plastic was also a constant presence.

This highlights the need for waste and fishing gear management interventions in the archipelago. The data collected from this expedition will be analysed and compared to pre-2016 surveys to inform management of the protected area and how best to ensure continued survival of these precious habitats. Long-term monitoring is essential to identify how coral bleaching events (one of which is expected in 2019) and coastal development could affect reef longevity. It was an honour to be involved in this incredible expedition and work towards protecting Cambodia’s vital reefs with such a passionate and skilled team.

Coral reefs are globally important harbours of rich biodiversity, providing sanctuary for 25% of all marine species. Credit: Roger Bruget

Fishing gear can smother corals and entangle marine life for years after it is abandoned. Credit: Roger Bruget

The team recorded ecological data from various marine sites to identify changes in reef health since MPA designation. Credit: Roger Bruget

Our imposing research vessel the Dive Shop 1 and our affable deckhand Mr Ly – courtesy of FFI partner the Dive Shop Cambodia. Credit: Kieran Murray/FFI