Hambantota Port : A Marine Biodiversity Hotspot

COLOMBO (News 1st); A new baseline study by the Department of Fisheries and Marine Sciences, at Ocean University of Sri Lanka has revealed a thriving ecological marvel beneath the waters of Hambantota International Port (HIP). 

Despite being an artificial breakwater, the reef at HIP now supports the highest diversity of reef-associated fish in Southern Sri Lanka, outperforming natural sites like Weligama, Polhena, and Thalaramba.

Using a standardised swim-timed transect method, covering areas of 5 by 20 meters at depths between 0.5 and 5 meters, researchers catalogued observed visual counts of fish by family and feeding behaviour. While Weligama and Polhena showed respectable biodiversity (with Shannon-Weiner Diversity Index scores of 1.8 and 1.6, respectively), they lagged behind HIP in both species richness and ecological balance. Thalaramba, once a promising site, recorded the lowest diversity (1.1).

HIP’s remarkable fish diversity at 2.3 on the SWD index isn’t accidental, it’s sustained by a natural ecological balance rarely seen in similar coastal areas. A healthy population of herbivorous fish, such as surgeonfish and damselfish, play a vital role in this balance by feeding on fast-growing algae that can otherwise smother corals. Their presence allows coral species to thrive and recover naturally.

“Algal domination is a serious concern globally, as it can suffocate coral reefs and trigger irreversible ecosystem shifts,” explained Marine Scientist, Dr. M.F.M. Fairoz, who is leading the study. “But at HIP, we’re seeing the opposite, a reversal of that trend, thanks to abundant herbivores fish species that keep the reef clean, balanced, and productive.”

This natural "cleaning service" helps coral colonies regenerate, increasing the reef’s structural complexity and resilience. Unlike other reefs in the region, many of which suffer from ornamental fish harvesting and nutrient runoff, HIP benefits from a unique combination of factors: minimal human disturbance, low pollution levels, a complex artificial reef structure, and open ocean connectivity that ensures healthy water flow.

These ideal conditions have created a productive food web that supports everything from small ornamental species to larger commercial fish. Over 8 species were found unique to the Hambantota Internal Port bay, including the Blue Green Chromis (Chromis viridis), Redfin Butterflyfish (Chaetodon lunulatus), and economically important species such as trevallies and emperors were also present, along with lobsters, highlighting the reef’s role in supporting both biodiversity and fisheries.

Local fishers have experienced high catch rates around HIP, suggesting that the reef may also serve as a breeding and nursery ground for marine life.

One of the clearest indicators of HIP’s ecological health is the mix of fish feeding types, a concept known as "trophic balance." In simple terms, it means having the right mix of plant-eaters, meat-eaters, and those that eat both.

HIP shows an impressive balance: 34% of its fish are herbivores, 58% are carnivores, and 40% are omnivores. This spread supports a strong, stable food web where energy flows smoothly between species, just like in a healthy natural ecosystem.

The reef has coral cover between 30% and 35%, a high percentage for the region. This diversity and balance help different species coexist and strengthen the reef’s ability to bounce back from environmental stress.

HIP’s Coral growth on semi artificial structures sends a powerful message: artificial structures, when thoughtfully designed and placed, can evolve into vibrant marine habitats. Though the reef was originally built for port protection, it now serves as a model for eco-conscious coastal development.

“We now have a scientific baseline that positions HIP as a model for integrating ecological principles into coastal infrastructure,” the research team said. “It’s an opportunity to rethink how ports, tourism, and fisheries can coexist with conservation goals.”

This study could influence how future coastal projects are planned, not only in Sri Lanka but globally. Rather than viewing development and conservation as conflicting goals, HIP shows they can work together.

Researchers emphasise the need for long-term monitoring, across seasons and different times of day, to better understand the reef’s dynamics and ensure its protection. They also see potential for HIP to become a hub for reef education, eco-tourism, and sustainable fisheries.

In short, the artificial reef at Hambantota International Port is no longer just a breakwater—it’s a breakthrough.

Source: Hambantota International Port