Observation: Key differences in land and ocean management and behaviours are obvious on a recreational scuba dive

​I recently spent 10 days on a recreational diving holiday in Fiji, where I spent the majority of my time diving the sheltered and oceanic waters either side of the Great Astrolabe Barrier Reef to the south and south-east of Kadavu Island. The Great Astrolabe Barrier Reef sits on the northern edge of the Astrolabe Trough and runs parallel to almost the entire southern and eastern coast of Kadavu Island. Kadavu Island itself is widely regarded as one of the most traditional and authentic of the Fijian Islands, with respect to its lack of infrastructure development, land clearing, and industry. Kadavu is still relatively subsistence, with the exception of kava which is grown for consumption across Fiji. However, the lack of land clearing for roads and development results in the perception that the island, which is quite mountainous and steep, is relatively unpopulated.

Images: (left) Kadavu Island, located south of the Fijian mainland (Google 2017) | (right) Kadavu Island and the Great Astrolabe Barrier Reef from the air (Personal archive 2017)

The effect of this was clear as day underwater. The Reef was in near-pristine condition, and with very few tourism centres in the area, we were the only divers on the reef, with the exception of local fishermen. The evidence of marine protection was astounding. Corals were well established, structurally diverse, abundant, and reefal systems were highly diverse in terms of corals (both soft and hard corals) and fauna species. It was clear that the limited coastal development, small scale land clearing and subsistence agriculture, limited terrestrial run-off, and limited interaction (through fishing and tourism) had maintained the water quality and condition of the reef to world-class ecosystem standards. It was quite a pleasure.

Images: Personal photographs of the Great Astrolabe Barrier Reef - abundant and diverse

Fast forward to less than two weeks later and I am back in Queensland, snorkelling the inner Great Barrier Reef near Townsville. The turbidity alone results in less than a metre of visibility in places (granted I was much shallower than during my dives in Fiji), and the corals are clearly struggling. In some areas, they are strong and recovering, but they are young and lack the skeletal structure observed in the relatively undisturbed waters of the Great Astrolabe. Now the comparisons are definitely not equal, and I was not in Fiji to conduct any scientific surveys. However, just based on my observations, the difference between the two inner portions of reef were astounding. As a coastal scientist, it is not new information that the Great Barrier Reef is struggling following decades of questionable coastal, land and marine management, not to mention the two consecutive years of wide-spread bleaching the reef has endured. 

Images: Personal photographs of the Great Barrier Reef (inner reef) close to the Whitsunday Islands - young corals recover from physical and human impacts, but there remains a lack of structural diversity.

What my trip to Fiji showed me was that nothing happens in isolation and it is often impossible to blame one decision, one event, or one project on the health or impact to any ecosystem. Understanding and recognising cumulative impacts is critical for coastal and marine management, and it is premature to assume that a single solution is the right solution for managing or restoring ecosystems and ecosystem function. The case of the Great Barrier Reef is complex. It is an extensive and complex system with highly diverse yet localised ecosystem characteristics and structure – for example, it is almost impossible to compare the inner and outer reef areas with one another as the influences and systems are entirely different. However, understanding all of those influencers and systems is key to determining the best approach to conservation, management and restoration. It is impossible to blame one event alone for the loss of habitat or destruction of the environment, without considering all contributors and their weighting in cumulative terms.