A forgotten fish resurfaces in an underexplored north-western seascape of Sri Lanka, almost after 200 years

Comparison with historical descriptions and scientific literature indicated that the fish was Fibramia thermalis, a species whose connection with Sri Lanka stretches back nearly two centuries. Formerly known as Apogon thermalis, the species was first recorded from Sri Lankan waters through collections associated with the French naval expedition of La Chevrette in the late 1820s. The recent identification was based on photographic evidence and comparison of external morphological characteristics, including body form and coloration, with historical descriptions and published records. Molecular analysis is planned to provide an additional level of confirmation.

The rediscovery does not necessarily mean that Fibramia thermalis disappeared and later returned. Rather, it highlights a gap in exploration: the species may have persisted in Sri Lankan waters while remaining overlooked by the few recent scientific investigations and unrecorded for almost 200 years.

The finding comes as IUCN Sri Lanka begins work in the Erumaitivu-Kakkativu Seascape in Kilinochchi District through the project “Conservation of Coral Reefs Associated with the Erumaitivu-Kakkativu Seascape for Community and Ecosystem Resilience,” supported by Sampath Bank PLC. Baseline surveys are documenting coral reefs, associated species and ecological conditions, helping to establish a scientific foundation for longer-term conservation action and future monitoring. One of the first surveys has already demonstrated how much remains to be learned about this seascape.

Northern Sri Lanka's coastal and marine environments remain less documented than many better-studied reef systems elsewhere in the country. For decades, scientific fieldwork in parts of the north was constrained by Sri Lanka's civil conflict, disrupting the continuity of marine surveys and biological collections. As a result, important gaps remain in knowledge of species distributions, reef condition and ecological processes. Renewed scientific access and conservation initiatives now provide an opportunity not only to fill historical gaps, but also to establish contemporary ecological baselines at a time when coral reefs are facing increasing environmental pressures.

The rediscovery of Fibramia thermalis therefore represents more than an interesting species record. It highlights the biological importance of the Erumaitivu-Kakkativu Seascape and the value of systematic biodiversity surveys in a region that has remained understudied for decades. For the research team, the finding also raises a broader conservation question: how much do we really know about the reefs and associated ecosystems of Sri Lanka's northern coast?

Surveys now underway are beginning to build a clearer picture of the seascape's coral reef ecosystems, species assemblages and conservation needs. As this evidence base grows, it can support decisions on habitat management, restoration, sustainable use and other locally appropriate conservation measures. The observation of Fibramia thermalis within a degraded coral reef also offers an important reminder: ecologically altered habitats should not automatically be considered biologically unimportant. Even degraded reefs can retain species and ecological information that may otherwise remain overlooked.

For the Erumaitivu-Kakkativu Seascape, this rediscovery may be only the beginning. Continued surveys could reveal further records that help fill long-standing gaps in our understanding of northern Sri Lanka's marine biodiversity and strengthen the scientific basis for conserving this little-studied seascape.

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