September 01, Colombo (LNW): A newly released study by the Department of Fisheries and Marine Sciences at Ocean University of Sri Lanka has uncovered an unexpected ecological success story beneath the waters surrounding Hambantota International Port (HIP).
What began as a man-made breakwater has now transformed into a thriving underwater habitat, boasting the richest diversity of reef-associated fish recorded in the southern region of the island.
Outshining long-recognised natural sites such as Weligama, Polhena, and Thalaramba, the reef at HIP has become a biological hotspot. Using standardised swim-timed transects—surveying underwater zones 5 by 20 metres wide at shallow depths between 0.5 to 5 metres—researchers observed, identified, and classified fish by species, family, and feeding behaviour. The findings were striking.
HIP scored 2.3 on the Shannon-Weiner Diversity Index (SWD), significantly surpassing Weligama (1.8), Polhena (1.6), and Thalaramba (1.1). Whilst those natural reefs still host notable marine life, they have been increasingly impacted by human activities such as overfishing, ornamental fish collection, and pollution runoff.
HIP, by contrast, benefits from a rare mix of ecological stability and minimal interference—factors which appear to have allowed marine life to flourish.
According to Dr M.F.M. Fairoz, who is leading the research, HIP is showing an ecological balance rarely observed in coastal development zones. “Globally, we’re witnessing algal overgrowth smothering coral reefs and collapsing marine food webs,” he noted. “At Hambantota, we’re seeing a reversal—an artificial reef structure hosting a balanced, self-sustaining marine ecosystem.”
At the heart of this balance is a healthy herbivore population—especially surgeonfish and damselfish—which graze on algae and prevent it from overwhelming coral colonies. This natural algae control allows coral growth and regeneration, creating structurally complex habitats that attract an even wider range of species.
The researchers recorded over eight species exclusive to HIP, including the vivid Blue Green Chromis (Chromis viridis) and Redfin Butterflyfish (Chaetodon lunulatus), alongside economically valuable species such as trevallies, emperors, and lobsters.
The port’s reef also appears to support local livelihoods. Fishers operating around HIP have reported increased catches, suggesting the reef may serve not only as a biodiversity haven but also as a spawning and nursery ground for commercially important fish.
A key indicator of ecological stability at HIP is its trophic diversity—the distribution of fish by feeding type. The study found that 34 per cent of observed fish were herbivores, 58 per cent carnivores, and 40 per cent omnivores, reflecting a robust and resilient food web. Coral cover at the site was measured between 30 per cent and 35 per cent—a notably high figure for the region.
What makes the site even more remarkable is that none of this was planned in the conventional sense of conservation. The breakwater was originally constructed to shield the port from strong ocean currents and waves. Yet, over time, its unique structure, combined with open ocean circulation and low pollution, created the perfect conditions for reef development.
Researchers believe HIP now presents a rare opportunity to reimagine the relationship between infrastructure and ecology. “This is more than a one-off success—it’s proof that artificial structures, when carefully sited and allowed to integrate with natural processes, can evolve into valuable ecosystems,” said the research team.
The findings could have far-reaching implications, potentially influencing how ports and coastal infrastructure are designed not only in Sri Lanka but around the world. With global coastlines under increasing pressure, HIP serves as a blueprint for harmonising economic development with environmental stewardship.
Plans are already being discussed to establish long-term monitoring, education programmes, and eco-tourism initiatives centred around the reef. There is also growing interest in exploring HIP as a site for sustainable fisheries and marine science outreach.
As researchers continue to study its seasonal patterns and species behaviour, the reef at Hambantota International Port has emerged as something far greater than a protective barrier—it has become a living example of how human engineering and ecological resilience can, under the right circumstances, coexist and thrive.
