Features
Recent earth tremors in Sri Lanka
– a critical review in relation with such activity in Tamil Nadu and the orogenesis of Himalayas based on a new theory of cratons and mobile belts in the Indian peninsular
By DULIP JAYAWARDENA
Former Director Geological Survey Department and retired Economic Affairs Officer, United Nations ESCAP
There were recent reports of earth tremors in the Buttala and Wellawaya areas in Sri Lanka and statements made by local earth scientists failed to give any scientific explanations as regards such activity.
An attempt is made to explain such activity in relation to seismicity in Sri Lanka compared to Tamil Nadu as well as the orogenesis of the Himalayas in relation to a new theory of cratons and fold belts in India and its extrapolation to Sri Lanka.
There was a news item in the local media that if a major earthquake occurs in the Himalayan region there will be tremors felt in Colombo as well as in Jaffna.
Historical seismicity in the Himalayan region has been analysed and its slip potential in the 21 Century recorded (Rodger Bilham roger.bilham@clorado.edu ).
The seismicity of Sri Lanka and Tamil Nadu are compared to understand mountain building in the two regions as Sri Lanka resemble crystalline metamorphic rocks of South India.
It is recommended that the theory cratons and mobile belts that has been postulated in India focusing on the Tamil Nadu region be extended to Sri Lanka to explain present earth tremors in Buttala and Wellawaya areas.
COMPARISON OF ALTITUDES AND SEISMIC RECORDS BETWEEN SRI LANKA AND TAMIL NADU
The highest mountains in Sri Lanka are Pidurutalagala (2524 metres msl), Kirigalpotha (2396 metres msl), and Samalakanda – Adam’s Peak (2243 metres msl)
As compared to Sri Lanka the heights of 77 mountains range from 2695 meters msl to 522 metres msl from the Indian Peninsular.
Tamil Nadu, which is a part of Peninsular India, compared to the highest peneplain of Sri Lanka (Wadia 1945), has three mountains namely Anamuda (2395 metres msl ) , Meesapullimala (2640 metres msl) and Kolabetta (2629 metres msl) -Wikipedia.
Accordingly, it is evident that the highest mountains in Sri Lanka can be closely related to those of Tamil Nadu subject to the same orogenesis or mountain building.
SEISMIC HAZARD ANALYSES FOR STATE OF TAMIL NADU SOUTH INDIA
A study by G. P. Ganapathy Assistant Professor, Centre for Disaster Mitigation and Management VIT University Vellore 632 014 Tamil Nadu India seismigans@yahoo.com and Rajaratnam S. Professor, Centre for Disaster Mitigation and Management, Anna University Chennai 600 025 Tamil Nadu, India ( drrajarathnam@yahoo.com ) have extensively analyzed seismic potential sources of Tamil Nadu State and are summarised in Table 2 of their paper titled, “Seismic Hazard Analyses for Tamil Nadu State: A Deterministic Approach “and published in the Jour. Engr. Geol. Vol.XXXV1 NO1.4
Tamil Nadu State covers 130 ,058 sq. km approximately twice the size of Sri Lanka which encompasses only 65 000 sq. km. Figure 1 gives a large number of lineaments which are seismic prone and it is interesting to note that such lineaments especially in the South Block may extend to Sri Lanka and Figure 2 indicate identified seismic potential sources in this block.
SEISMIC POTENTIAL SOURCES OF TAMIL NADU
Table 1 of the above research paper analyses seven sources seismic potential sources with lengths varying from 315 km to 42 km with cumulative number of earthquakes ranging from 5 to 1 with magnitudes varying from 6.0 to 5.0 (M) observed from historical /instrumental earthquakes and peak ground acceleration (PGA) in g determined using m varying from 0.212 to 0.078 . It is noted that PGA is high in earthquakes with magnitude 6.0 and low in magnitude 3. Further PGA in Chennai, Coimbatore, Salem, Madurai and Tiruchirappalli cities varies from 0.107g, 0.133g, 0.012g ,0.77g and 0.113 g respectively. It is noted that the southeastern part of the State shows high values because of a high earthquake data for the years 1800 to 2004 It also explains that the southern part of the State which may extend to Sri Lanka shows comparatively low seismic hazards.
SEISMIC RECORDS AND POTENTIAL OF SRI LANKA
It is reported that Sri Lanka had no seismic records up to 1800. However from the period 1615 to 1800 earthquakes were reported close to Sri Lanka in the northern Indian Ocean and Coimbatore- Nilgiri Hills. (Seneviratne H.N et al ( DOI :http://doi.org/10.4038/engineer.v53i2.7412)
Newspaper reports are available in the National Archives, Sri Lanka in 1882 ,1924, 1938 and 1944(Ceylon Observer) on earthquakes that had occurred during these years. However no deaths have been reported although there was damage to property (Gunasekera K.W (2000) Sunday Observer ,p34)
Seismic records from 1909 to 1992 were from a seismograph installed in 1909. However, no data are available since 1992 as it was not fully functional.
It is reported that from the year 1823 to 2010 earth tremors and earthquakes in Sri Lanka varied from 5.9 to 3.7 on the Richter Scale and most of such tremors were recorded in the Comorin Ridge Failed Mannar Rift Zone (Seneviratne et.al).
Sri Lanka has been identified as a Mid Plate Platelet lying between Antarctica -India -Africa and Madagascar ( Curry 1984 adopted by Crawford (1974 )and Katz (1978).
In 1823 there was an earthquake of 5.8 Magnitude at Mandawela , in close proximity of Colombo with coordinates 7deg. Lat. and 80 deg. Long. There were no deaths but damage to property were recorded. There was also an earthquake of 5.9 Magnitude at Lat. N 6.5 and Long 79 E close to Kurunegala.
It is interesting to note that Sri Lanka within a latitude of 7.8731 deg. North and 80.7718 East had 18 earthquakes or tremors between the period 1823 to 2010 a period of 187 years. However, the number of tremors of insignificant nature during this period was 670.
SEISMIC RECORDS IN SRI LANKA AFTER 1992
- Fig. 1. Schematic geological map of Sri Lanka, after Kroner et al 2013
- Fig. 2. Map of Vijyana Complex with locations of sampling, edited after Kroner et al 2013. The tectonic mixed zone between the Highland Complex and the Vijayan Complex is highlighted as light-grey in colour.
The Geological Survey and Mines Bureau (GSMB) commissioned three seismometers, one at Pallekelle in year 2000 (PALK) connected to the Global Seismic Network (GSN)and the others in 2010 Mahakandarawa (MALK) connected to GEOFON) Network and Hakmana (HALK)connected to GEOFON (Geo-Network operated by Germany).
It is of importance that a network of seismometers be established in Colombo and the Western Province and a network of seismometers covering the entire Island to establish relationship between earthquakes and development activity accelerated recently in Sri Lanka. (Senaviratne H.N. et. al. 2020)
It has also been revealed that an earthquake of magnitude 6.9 (475-year return period) along the Mannar Rift Zone identified earlier in this report.
SRI LANKA HAS THE LOWEST GRAVITY RECORDED IN THE WORLD
The European Space Agency (ESA) carried out a four-and-a-half-year Gravity Field and Steady – State Ocean Circulation Explorer (GOCE) mission to learn what constitutes the surface beneath the Earth and discovered that the lowest negative gravity was south of Sri Lanka.
A geoid is the equipotential surface that coincides over the oceans with the same sea level. It is noted that the earth becomes flattened around the equator and the distance from equatorial areas to the center of the Earth is more than from the poles to the center. (Roar media Sachith Mendis (https://roar.media/english/life/reports/sri-lanka-least-earth-place-world )
It is also revealed that launching of space satellites will be much cheaper due the low gravity and due to no land surface directly south of Sri Lanka.
EARTHQUAKE OF 1615 IN SRI LANKA
An earthquake of magnitude 8 or 9 on the Richter scale was reported on 14 April 1615 evening offshore that caused extensive damage in western part of the Island. The worst hit area was Colombo and 2 per cent of Colombo Fort was destroyed. It has been reported that nearly 200 houses were destroyed with nearly 2000 casualties. Accordingly, moderate sized earthquakes cannot be ruled out in Sri Lanka. (Muhandiram P. M. S. S. B. <https: loes18.wildapricot.org/article _earthquakes-text= According to this document2 % of Colombo Fort got destroyed.
GRAVITY MAP OF SRI LANKA
A Gravity Map of Sri Lanka was compiled and produced in 1975 by the Geological Survey Department (present GSMB) on the scale of 1: 1. 000,000 by T. Hatherton, D. B. Pattiarachchi and V. V. C. Ranasinghe with an appendix by R.B. Evans.
A total of 1,170 points were established covering the whole Island in respect to 19 base stations and about 87 per cent of observations where in areas less than 150 meters msl.
The horizontal distance and heights of the 1971 gravity observations were from 1 -inch topographic maps covering Sri Lanka.
Most of these gravity stations were tied up with the trigonometrical survey stations of the Survey Department. When these stations were opened it was revealed that there was movement due to upliftment.
A contour map of complete Bouguer (gravity anomaly corrected to the height of its measurement) anomalies with the locations of gravity observations was produced.
The gravity map has revealed a negative gravity low on the Highland -Vijayan boundary in the east of Sri Lanka.
(To be concluded)
Features
Human dignity comes centre stage in Afghan refugee deportation crisis
The mounting mute and unmitigated suffering of the ordinary people of Afghanistan is coming to the fore once again in ongoing efforts by some neighbouring states to deport tens of thousands of Afghan refugees to their country of origin. As in the case of the majority of refugees the world over the Afghan refugees too are caught up in cataclysmic wars and conflicts not at all of their making.
International reports indicate that some six million Afghan refugees have been virtually pressured, to date, to return to Afghanistan by Pakistan and Iran, for instance, on the basis apparently of stringent policies on refugees adopted by the latter. Many refugees are on record that although they are officially identified as of Afghan origin this is the first occasion on which they are seeing the inside of Afghanistan, since thus far they have been living, particularly in Pakistan, as virtual natives of the latter.
‘They are part of the biggest cross border movement of people in recent history, a UNHCR source was quoted saying. However, barring the latter UN agency and a few well wishers, the refugees are being seen as a virtual parasitic and unwanted presence by sections of the publics who have thus far been compelled to have the refugees among them.
The refugees’ haplessness is compounded by the fact that they have been reduced to almost destitution. Having possessed virtually nothing by way of material assets they are getting back to Afghanistan a dis-empowered, dispossessed people.
For well over a century Afghanistan has been at the centre of the big power rivalries of South Asia. The country has been intensely coveted by the majority of major extra-regional powers from the turn of the last century primarily on account of its strategic geographical location, besides some of its natural resources.
Those powers that gain a military foothold in the country would be enabled to bring the majority of Afghanistan’s neighbours within their sphere of influence and power. Some of these are, China, Pakistan, Iran and India. Besides there are the one time Soviet Central Asian Republics, control over whom would be of considerable value, from a number of viewpoints, to expansionist powers.
These attractions account for the appeal Afghanistan has continued to exercise over the majority of extra-regional powers whose presence has proved decisive in the shaping of international politics over the decades. Those powers who have featured majorly and are continuing to do so are, the US, Russia, China and the UK to a lesser degree.
However, the Afghan refugee issue or the ‘Long- suffering’ of the ordinary people of Afghanistan could be considered as having gained exceptional prominence with the Soviet invasion of Afghanistan of 1979.
The latter event needs to be seen as a notable turning point in the last century’s international politics. The initial disintegrative cracks in the Soviet Union were beginning to appear and Islamic fundamentalism was seen by the Soviet authorities as making divisive inroads into their Central Asian Republics.
The influence of Islamic fundamentalism had to be stymied following the Islamic Revolution in Iran in 1979 and Afghanistan came to be seen by the Soviet authorities as a potential hotbed of such religious revolutionary fervour. Thus came about the Soviet invasion of Afghanistan and its subsequent degeneration into a military quagmire for both the Soviet Union and the US.
Thus it was only a matter of time before Afghan refugees began to swell in numbers in neighbouring states. They were haplessly caught up in the ‘cross-fire’ between the Soviet backed Afghan security forces and the Afghan militant resistance which evolved into the Taliban.
As is known, the Afghan resistance came to be armed and backed by the US subsequent to Afghanistan being over-run by the Soviet Union. Thus, Afghanistan became the last proxy war theatre in the long -running Cold War between the US and the Soviet Union. More than a decade of blood-letting convinced the Soviets that there was no choice but to quit Afghanistan.
Thus, to a considerable extent, the Afghan refugees are the victims of big power armed rivalries which are continuing to render the world a most ‘dangerous place’ for ordinary people. The UN agencies seem to be doing their best for the refugees of Afghanistan and most other refugee categories but the continued humiliation of such victims of war would need to be mitigated by the international community to the extent possible. Forcible deportation of refugees in particular may need to be eschewed and outlawed.
Being subjected to an acid test at this juncture is the Universal Declaration of Human Rights (UDHR). It is the latter seminal convention that made the protection of human dignity a cardinal value for the world community.
All those sections that subscribe to international humanitarian law and democratic opinion world wide need to come together, may be under the aegis of the UN, to work out how primacy could be attached to the UDHR and its principal mandate of protecting and perpetuating human dignity and worth.
This is no easy challenge to meet but it needs to be addressed urgently before currently rampant ‘international disorder’ grows well out of control.
The US and Russia are especially obliged to go to the rescue of the Afghan refugees since the Afghan crisis is of their making to a considerable extent but no help could be expected from them because their governments are strongly right wing in orientation. It would be far-fetched to expect of them a strong social conscience.
However, the UN and like-minded organizations need to dialogue strongly with the Taliban regime in Afghanistan with a view to bettering the well being of Afghan civilians. No longer could the lot of the latter be allowed to be dismissed by the Taliban government as ‘an internal matter.’
If the Taliban regime is being assisted by the UN, the former is strongly obliged to be accountable to the international community. The UN would need to non-obtrusively convince the Taliban government that it cannot ignore the essential needs of its civilian populace and the empowering of women forms a central component of this broad programme of work. The UN’s diplomatic finesse needs to come to figure here in a major way.
Refugees everywhere should ideally be re-accommodated in their countries of origin or native lands. However, unless and until their dignity is ensured by governments and other quarters that matter such endeavours would prove to be self-defeating.
Features
A Defence Minister after 38 years: Partnership without capture
Indian Defence Minister Rajnath Singh’s arrival in Colombo is not a ceremonial call. It is the political face of a security relationship that has been rebuilt, layer by layer, since 2024. Sri Lanka should take the capability on offer, and keep the right to say no.
by Mahil Dole
Senior Superintendent of Police (Retd.)
Indian Defence Minister Rajnath Singh is in Colombo for a three-day official visit, the first by an Indian Defence Minister in 38 years. The last such call was by K. C. Pant in 1988. That long silence itself tells a story. For nearly four decades, defence business between the two neighbours was handled by service chiefs, training colleges and quiet staff talks. New Delhi has now chosen to put a political minister at the centre of the relationship, and to do so immediately after a dense sequence of Indian visits and against a harder contest in the Indian Ocean.
The visit will be read, in Delhi, Beijing and Washington, as a signal. Our task in Colombo is narrower and more serious: to convert the signal into national capability without converting the island into a platform.
Not an isolated visit
Singh’s programme is the latest layer in an unusually concentrated Indian engagement since President Anura Kumara Dissanayake assumed office in September 2024. Prime Minister Narendra Modi’s state visit in April 2025 was the first by any foreign head of government after the new presidency. Seven documents were signed. Among them was the first comprehensive India–Sri Lanka Defence Cooperation Memorandum of Understanding, a five-year umbrella covering joint exercises, training, port calls, humanitarian assistance and disaster relief, information exchange and possible defence-industry cooperation. Either side may terminate it with three months’ notice. That exit clause is not a detail. It is the difference between a structured partnership and a treaty alliance.
What followed was a rhythm, not a one-off. The eighth Annual Defence Dialogue was held in Colombo in June 2025. The Indian Navy Chief called in September 2025. After Cyclone Ditwah, India arrived as a first responder and later announced a reconstruction package of some 450 million US dollars; External Affairs Minister S. Jaishankar came as Special Envoy. In January 2026 the Indian Army Chief, General Upendra Dwivedi, handed over vehicles and training aids, opened a friendship corner at the Defence Services Command and Staff College, and laid a wreath at the IPKF memorial in Battaramulla. The Indian Vice-President visited in April. Foreign Secretary Vikram Misri was in Colombo on 5 August with rupee lines of credit for railways and other priorities. Later that month, Sri Lanka’s Navy Commander, Vice-Admiral Damian Fernando, made his first overseas visit in command, to New Delhi, and met the Chief of Defence Staff, the Defence Secretary and the Navy Chief.
Singh therefore arrives not as a stranger opening a file, but as the political seal on work already in motion. He met President Dissanayaie, who holds the defence portfolio, the Prime Minister and the Defence Secretary. The itinerary also takes in the IPKF memorial, the Defence Ministry, the parliamentary precincts, Gangaramaya Temple, a likely reception on an Indian Navy ship, the National Defence College, and the Sita Amman Kovil in Nuwara Eliya. Indian High Commissioner Santosh Jha has said relations have “never been better” in decades. The visit calendar, at least, is not an invention.
What already stands on the defence floor
It is important to be precise about what already exists, so that we do not mistake institutionalisation for a sudden tilt.
Training is the deepest bond. India is the largest foreign trainer of the Sri Lankan armed forces, offering on the order of a thousand to twelve hundred vacancies a year. One naval accounting records more than two thousand Sri Lankan naval personnel passing through Indian courses over nine years. Shared classrooms produce shared language, shared drills and personal networks that outlast any single government. Reports ahead of this visit point to three new memoranda, one likely on air-defence guns, one on cadet-corps links, and one on cooperation between the Sri Lanka Defence College and Indian defence institutions. If signed, those instruments would push the relationship into the next generation of officers, not only today’s operators.
Exercises are now routine rather than ceremonial. The twelfth edition of SLINEX, the bilateral naval exercise, was held in Colombo from 14 to 18 August 2025, with a harbour phase of professional exchanges and a sea phase of gunnery, boarding, replenishment and communications. MITRA SHAKTI, the army exercise with air elements, held its eleventh edition in Belagavi last November. A fourth bilateral diving exercise was conducted in Colombo in April 2026. The two navies and coast guards continue International Maritime Boundary Line meetings. An Indian Navy Dornier was based here for maritime surveillance from August 2022 to August 2025. A Maritime Rescue Coordination Centre was commissioned with an Indian grant of about six million dollars. INS Vikrant and INS Udaygiri took part in the International Fleet Review marking the Sri Lanka Navy’s seventy-fifth anniversary.
None of this is trivial. None of it, by itself, is alignment. Hardware, hours at sea and staff-college seats are instruments. What they become depends on command, data and political purpose.
National security questions that matter
Three questions should govern Colombo’s handling of the Indian Defence Minister’s visit.
The first is maritime domain awareness. Sri Lanka’s core security geography is not a land frontier. It is the exclusive economic zone and the sea lanes that pass our shores. The live threats are narcotics, people-smuggling, illegal fishing, and the possible relocation of cyber-fraud compounds. Conventional naval war is not on this year’s operational list. Indian help with sensors, hydrography, diving, boarding drills and search-and-rescue is therefore rational. The test is who owns the picture. Shared awareness is useful. Exclusive dependence on one partner’s fusion centre is a vulnerability. Australia’s Disi Rela programme against irregular maritime movement, Japanese passage exercises, and the United States capacity support, cutters, aircraft, humanitarian exercises, already exist. They should remain in the mix. Maritime security should be a Sri Lankan-led coalition of convenience, not an Indian franchise.
The second is the air and coastal defence gap. Talk of Indian air-defence guns is not abstract after the 2026 conflict in West Asia reached our own waters, the sinking of the Iranian frigate IRIS Dena off Galle, and later Iranian hulls lingering near the exclusive economic zone. The government’s public line was the correct one: no combat use of our territory, airspace or waters by any party; humanity first; sailors rescued. That posture only works if the state can see, and if necessary contest, its approaches. Accepting guns, radars or training is compatible with an independent foreign policy if command, basing and rules of engagement remain Sri Lankan. Integrating them into another country’s kill-chain would not be.
The third is internal security. Easter Sunday accountability, narcotics networks that run through ports and prisons, and communal peace are not separate from geopolitics. Partners price political risk. A state that cannot govern its harbours, its financial system and its extremist ecosystems will be offered “help” that looks like tutelage. India’s interest in counter-terror coordination and drugs overlaps with genuine Sri Lankan needs. The discipline required is the same as in any sound intelligence relationship: cooperate on targets; do not outsource the service.
The wreath at the IPKF memorial will be watched, as it was when the Indian Army Chief stood there in January. The years 1987 to 1990 remain raw in our political memory. The only stable line is professional honour to the dead, not a political rehabilitation of an intervention that divided this country.
How the region will read Colombo
India’s motive is not mysterious. Sri Lanka sits on the approaches to India’s southern seaboard. Chinese commercial and dual-use presence at Hambantota and Colombo Port City, and continuing engagement with the People’s Liberation Army Navy, is the backdrop. Pakistani naval units calling at Colombo, including a Chinese-built Hangor-class submarine earlier this year, only sharpen New Delhi’s preference for a denser security habit with us. Neighbourhood First and MAHASAGAR, Mutual and Holistic Advancement for Security and Growth Across Regions, are the language. The operational aim is that extra-regional navies do not treat Sri Lankan harbours as a default logistics base against Indian interests.
Our motive should be equally clear, and different. Geography makes India the permanent neighbour. Crisis behaviour, liquidity and fuel in 2022, the cyclone in 2025, the energy and remittance shock of 2026, has already shifted public sentiment. That is a political fact. It does not require Colombo to adopt India’s threat picture of China, or to freeze other relationships.
A workable posture is polyalignment with a spine. India is the deepest security and connectivity partner, domain awareness, disaster response, training, Trincomalee energy cooperation, grid links and rupee credit, on the condition that ports, exclusive economic zone access and intelligence fusion remain under Sri Lankan law. China remains a major economic and infrastructure partner; new exclusive strategic footholds should not be created, and debt and operational control must stay visible. The United States, Japan, Australia and Europe matter for markets, green shipping, extra training pipelines and non-traditional maritime threats. Ordinary naval diplomacy with Pakistan and others is manners, not signalling.
The government’s stated doctrine, an independent policy that does not favour any country, and territory that will not be used against a third party, is the right public frame. This week will test whether that frame can coexist with deeper, more structured Indian defence cooperation. It can, if the new memoranda are capability contracts with exit clauses, not political alignment documents.
Take help. Keep the choice
Colombo should treat the expected instruments as a capability audit.
On air defence, welcome sensors and guns that Sri Lanka can man, maintain and switch off. Reject any arrangement that requires foreign crews, foreign rules of engagement, or data that only flows one way. In cadet corps and staff colleges, take the training and keep a parallel pipeline with other professional schools so that the officer corps is not a single-source product. On the 2025 Defence Memorandum, measure implementation by Sri Lankan readiness, hours of maritime coverage, time-to-rescue, interdiction rates in the exclusive economic zone, disaster lift, not by the number of Indian ship-days in harbour.
Joint training should emphasise humanitarian assistance, counter-narcotics, hydrography, diving and lawful boarding. Those are the missions that serve the public and do not lock us into someone else’s contingency. Scenarios that only make sense in an India–China or India–Pakistan crisis should be declined politely and firmly.
Defence talks must also be bound to the prosperity agenda. Trincomalee as an energy and industrial node, electricity interconnection, port productivity and cyclone reconstruction are where security cooperation either pays the citizen or looks like militarisation. A Defence Minister’s visit that produces only wreaths and signed paper will be read in the region as alignment. A visit that also moves energy storage, disaster systems and maritime safety will be read as statecraft.
I write as a former police officer who spent a working lifetime on intelligence, counter-terrorism and the unglamorous work of keeping a multi-religious island in one piece. Geography gave us a seat at the table of Indian Ocean commerce and security. Institutions, energy policy, port performance and social cohesion will decide whether that seat produces prosperity, or merely more invitations to other people’s contests.
Singh’s visit should be received with courtesy, used with discipline, and remembered for what it adds to Sri Lanka’s ability to stand on its own water. Take the neighbour’s hand. Keep the island’s choices. Make sure every exercise, every gun and every training slot leaves us more able to say no the next time a great power asks to use our sea, our air or our soil. (18 sources)
This analysis is offered in the interest of national security, institutional reform, and public safety)
The writer is a retired Senior Superintendent of Police. He served as Deputy Director in charge of the Counter Terrorism Desk, State Intelligence Service, and later as Intelligence Coordinator to the Inspector General of Police. He is the author of Security Beyond Enforcement: Practical Approaches for a Safer Nation.
Features
Lost for 90 years: Rare Goby resurfaces in Jaffna
Rediscovery highlights rich, unexplored aquatic biodiversity in Northern Province
By Ifham Nizam
A small fish that vanished from Sri Lanka’s scientific records for nearly 90 years has resurfaced in the waters of Jaffna, providing researchers with a remarkable rediscovery and fresh evidence that the Northern Province still holds significant, unexplored aquatic biodiversity.
The Yellow-stripe Goby, Mugilogobius chulae (Smith, 1932), was recently found in the Karainagar area of Karaitivu Island during a biodiversity survey, almost nine decades after it was last scientifically recorded from Sri Lanka.
The discovery is particularly significant because the species had previously been known from the country only through a single historical specimen collected from Pedduru Thuduwa, Jaffna.

Discovery moment
Research scientist Janamina Bandara, a member of the team that made the discovery, told The Island that the fish was not initially identified as the long-lost species.
“We came across an unidentified Goby during our fieldwork, and it was only after a detailed examination of its external morphology that we were able to establish its identity as Mugilogobius chulae,” Bandara said.
“For us, it was an exciting moment because this species had not been confirmed from Sri Lanka for almost 90 years.”
The fish has a particularly interesting history in Sri Lankan ichthyology.
In 1936, renowned Sri Lankan zoologist P. E. P. Deraniyagala described a new fish from Pedduru Thuduwa in Jaffna in his paper,
“Two New Fishes from Ceylon”, published in The Ceylon Journal of Science.
He named the species Vaimosa valigouva. Subsequent taxonomic revisions established that Vaimosa valigouva was a synonym of Mugilogobius chulae, the currently accepted scientific name of the Yellow-stripe Goby.
However, no further confirmed records emerged from Sri Lanka for decades.
With the species absent from subsequent surveys and inventories, it eventually disappeared from the country’s national fish lists and from much of the scientific literature relating to Sri Lankan fishes.
The prolonged lack of records was also closely linked to the difficulties of conducting biological research in northern Sri Lanka.

Yellow-stripe Goby, Mugilogobius chulae
For decades, the civil conflict, restricted access, security concerns and limited opportunities for field surveys prevented scientists from systematically investigating many of the region’s aquatic habitats.
Consequently, while considerable advances were made in documenting biodiversity elsewhere in the island, northern Sri Lanka remained comparatively poorly explored.
Bandara said the rediscovery should, therefore, be viewed in a much wider context than the finding of a single fish.
He told The Island: “An absence of records does not necessarily mean that a species is absent. In the case of northern Sri Lanka, there have been enormous gaps in field data because large areas could not be studied systematically for many years.”
“This finding demonstrates how important it is to return to these habitats and carry out detailed surveys. There could be many more species, range extensions and rediscoveries waiting to be documented.”
The research team’s findings did not end with the Yellow-stripe Goby.
During the same study, the researchers also documented the Black-spotted Snubnose Goby, Pseudogobius melanostictus (Day, 1876), providing what they describe as the first confirmed northernmost record of the species in Sri Lanka.
The species had previously been reported mainly from lagoonal and brackish coastal environments in the western part of the country, while recent verified records were limited.
The new finding consequently extends the known geographical range of Pseudogobius melanostictus and adds an important northern record to Sri Lanka’s fish fauna.
Together, the two findings significantly expand the known distribution of both Goby species within Sri Lanka.
They also highlight the importance of small and often overlooked coastal, tidal and inland aquatic habitats in documenting the island’s biodiversity.
Goby species are generally small fishes that occupy a variety of marine, brackish and freshwater environments. Their habitats can include rocky shores, tidal pools, lagoons, estuaries, mangroves and other transitional aquatic ecosystems.

Black-spotted Snubnose Goby, Pseudogobius melanostictus
Because of their small size and preference for habitats that are often overlooked during large-scale biodiversity surveys, some Goby species can remain undocumented for long periods.
The latest research is, therefore, particularly relevant to understanding the aquatic biodiversity of the Jaffna Peninsula and surrounding islands.
According to Bandara, the discovery also demonstrates the importance of combining historical scientific literature with modern field research.
“The old records gave us an important historical reference, while the current fieldwork allowed us to connect that history with what is actually present in these habitats today,” he said.
The rediscovery of Mugilogobius chulae effectively reconnects modern Sri Lankan ichthyological research with Deraniyagala’s 1936 record.
It also establishes the new finding as the westernmost known occurrence of the species in the Indian Ocean, according to the researchers.
The study’s authors — Janamina Bandara, Sahan Randeniya and Aravind Manoj — say their findings underline the need for continued biological surveys in northern Sri Lanka.
The region’s aquatic ecosystems remain insufficiently studied, particularly in areas that were inaccessible or difficult to investigate for extended periods.
Bandara said the team expected that further exploration could produce more unexpected findings.
“We should not assume that we have a complete picture of Sri Lanka’s fish diversity. Particularly in the north, there are habitats that have received very little scientific attention,” he said.
“Every field survey can potentially change what we know about the distribution of a species. That is why continued exploration and proper documentation are so important.
The researchers have expressed particular concern about the need to document such species before changes to their habitats make future identification more difficult.
Coastal development, changes in water quality, habitat degradation and other pressures can affect small aquatic ecosystems, making baseline biodiversity information increasingly important for conservation planning.
The latest study, therefore, provides not merely two new distribution records but also a reminder of the value of maintaining and updating national biodiversity inventories.
The researchers thanked Dr. Helen Larson, Rohan Pethiyagoda, Madhura de Silva, Dr. Kasun Bandara and Neluka Fernando for their assistance with various aspects of the study.
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