In Memoriam for Sena S. De Silva

It was in April 1975 that Eveline and I were busy at the Vidiyalankara Campus of the University of Kelaniya near Colombo. I had been making a few excursions, guided by Francis, to places where I could observe certain species of fish, barbs, in the wild. So far so good, but these were densely populated areas, that could hardly be representative of the original habitat. Eveline was struggling to prepare the chemical tests of the natural waters, and some tensions had arisen over the availability of certain solvents. We did not understand the fine nuances of local bargaining, and the professor, for all his good will, couldn’t guide me to more natural abodes where Puntius nigrofasciatus (1) might be found. 

About at that point, Sena De Silva sauntered into our room. He had come to resume his position as a lecturer, having just finished his PhD in Stirling, Scotland, and he hadn’t been there when we arrived,. A slim, young man he then was, nearly 30 years old. It looked like he came to hear what the trouble was about, but perhaps he just came to meet us. What happened was like a sudden change of weather. The use of the chemicals was no longer a problem, and when I explained to him that I had been studying the behaviour of those fish in aquaria, and now wanted to know in what sort of environment they had evolved, he understood perfectly what I meant. In his imagination, he saw the region of his youth, far South in the river basin of Gin Ganga, where these and some other species of barbs were common in relatively undisturbed waters. He offered to make reservations for us for a week in the Kanneliya Forest Reserve, where we could stay at the Circuit Bungalow, meant for visiting officials. He knew the people who were in charge, and managed a lift for us with the landrover of a friend of his who had to go there anyway. Professor sent Francis with us to watch over our safety, which was very kind of his. There we observed the barbs in crystal clear forest streams, the kind of habitat where those colourful fish must have evolved. That week was worth our whole stay of 2 months in Sri Lanka.

Forty-five years later, on April 27th 2020, I sent this e-mail:

Dear Sena, I hope this finds you and Thuy in good shape. Have you been on trips of late? ............. Here we are in lockdown with some moderations. ........

Our joint papers on barbs seem to be still cited regularly. .....

Warm wishes to both of you, please keep in touch, Koen.

There was an immediate answer:

Hi Koen, Great to hear from you at this juncture ...... I am on to immune therapy and right now I am hospitalised for testing of the new therapy. ..........  

As for the academic front glad that our work is being still looked into. ....

Well Koen keep in good health and hope the world will come back to normality sooner rather than later. 

Warmest regards from self and Thuy, Sena.

A few days later, on May 6th, he passed away. On getting the message, my clearest emotion was as if a piece of my heart had been torn out.

It was in the 45 years between these two episodes that our true and professionally productive friendship flourished.

In January 1977 I was back in Sri Lanka, on the invitation of Ranil Deraniyagala to stay with him for a week and let myself be guided to the habitats of some more species of barbs. Sena and I had arranged to meet and go to Kanneliya Forest together, again with Francis. While during the first visit we had limited our observations to the immediate surroundings of the bungalow -  fortunately there was one large spawning location of the fish nearby, and a few smaller ones - we were much more free to move around with Sena’s car and because of his knowledge of the land. Thus we found some more breeding places, the largest containing as many as 150 individual fish during the height of the daily spawning period. We descended part of the bed of the Nannikita Ela on foot, and the same with a relatively flat stretch of another stream, Kondagala Ela, so as to get an impression of the density of places where the barbs spawned.  These were tricky things to do; the stones and rocks that formed the river beds were slippery at most sides and sharp at the others. In the more horizontal stretches with sandy bottoms, ‘our’ fish came to nibble at our feet. We found three barb species in this sort of stream: a fast swimmer, a static bottom feeder, and a manoeuvrer (P. nigrofasciatus). Years later this arrangement of species turned out to be a basic one.

We had long talks about a wide variety of subjects besides biology. Sena had come back from Stirling an expert in assessing what fishes eat, calculating growth curves,  sex ratio’s and sizes at first maturity, and a lot more. He had already begun applying these techniques to some of the barb species, and I carried home a first manuscript from his hand that I edited and submitted to the Netherlands Journal of Zoology. A second followed later, and more. He welcomed the new dimension of behaviour and was pleased with my broad biological and evolutionary approach (2).

He suggested that we should start a larger project with a student of mine, and collect fish and physical data through a full year, so that we got a better idea of annual cycles of all common species. The analyses of guts, growth and ovaries could be done at his lab. That is how Jalb Schut came to work in Sri Lanka for a year and a half. Fortunately, the Dutch National Science Foundation (WOTRO), who had supported my visits, was willing to pay for the project. It resulted in a fair overview of all barbs and some other carp-like fish species that lived above flood level (3). Shortly before the start of the project, Sena was appointed professor at the new campus of Ruhuna Universty at Matara, near the Southern tip of the isle. Jalb operated from Colombo. This caused no logistic problems, since he and Sena often met. Next, a large number of students from Leiden continued the work, with Matara as their base, last in 1987. It was always Sena who first suggested the projects, and he was their great host and director on the spot. He was as good to the students as he had been to me.

In 1982 we were both invited to the workshop on sustainable clean water in Kuala Lumpur. By the time, Sena had acquired a prominent status in NACA, the network of aquaculture centers Asia-Pacific, of which he was to be director-general many years later. Prior to the conference, I had been bivouacing at the deserted university campus, and I was so happy to see Sena when the meetings started. As a convenor of a session, he payed attention to economic and food-yield aspects of indigenous fish faunas as well as to the necessary conservation of the habitats. To me, educated to consider economy as of secondary value, this added new vistas.

After the workshop, we flew to Sri Lanka together to plan the next project. In the field, we inspected some habitats that Sena had discovered, completing the picture that had emerged from Jalb’s project. We visited Kanneliya Forest, where the area of our earlier observations had been completely left by the Ceylon Plywood Company. We were all alone in the forest. Sena spotted some wild elephant droppings and feared that some wild male might suddenly appear and attack us. A voice like a laughing man made me start, but I could soon identify it as coming from a Hornbill. Still... But no elephants came into view, much to our relief.

In all, I made seven visits to Sri Lanka, the later ones to visit our projects, and Sena and I had great meetings every time. I shouldn’t forget the enjoyable meals we shared. At the Kanneliya Bungalow, for instance, and I am reminded in particular of Palmyra Restaurant in Colombo, right across the road from the hotel where I used to stay. They served delicious hoppers and curries.

After 1987 everything changed. My (parallel) cooperation with the Fisheries Department at Thiruvananthapuram, S India, came to an end when  Padmanabhan retired in 1985, soon followed by Professor Nair. In Sri Lanka, the civil war of Tamils and Singhalese had been going on for a while in the North. But when there were bomb attacks in Colombo, I was relieved when all our students were back home in their own country. The South of Sri Lanka suffered from internal strife between Singhalese factions too, and Sena’s work came to be  encumbered by student strikes at Matara, where he was once shut in his office for a full day. Finally, not feeling able to work properly, he emigrated. First to Singapore, and from there to Australia. There he found a place as professor of Aquaculture at Deakin University at Warrnambool, after his retirement continued as an honorary professorship. His busy time with NACA came a little later. All this meant the end of our common field studies in Sri Lanka. Sena unofficially maintained connections with the staff of the Ruhuna Institute, much to the benefit of the studies of aquatic biology there, and with me. Publications inspired by our projects kept coming until very long after the field work had ended.

Every time I left Sri Lanka, I expected that we would meet again. Sena did visit The Netherlands on one or two occasions. And of course there were (ir)regular contacts via e-mail. There was a long pause in our meetings, and when I bungled an opportunity - or perhaps we bungled it together - to meet in Australia in 2007, it had to wait until 2014 before we could arrange to actually see each other at the Utrecht Central Station in this country. It was an emotional meeting; as if time fell away, we picked up the threads where we had left them. “You haven’t changed,” I said; “only your hair is white.” and so it was. We had lunch together in town and a stroll in the streets after it; but already from seconds after our first words, I knew again why we had always got along so well and  worked together so smoothly. It is those unconscious affinities that make a relationship, and this was a rare one. When I wrote this to him after he had returned home, he responded that he had felt the same.

We kept in touch after this, even more conscientiously after he knew he had cancer. He bore it with courage, continuing his work and guidance of students to the very last. He never sounded like dangerously ill, right through all the chemo-therapies. And, as cited above, he looked forward to the future in his last mail to me.

Farewell, Sena; you were a giant, and one with a warm heart!

Sena and me December 2014; Utrecht.

(1)  The 'Black Ruby' or in Singhalese: Bulath Hapaya.
(2)  On p. 22 of Barbelenverhalen I, you see him observing at a spawning place.
(3) De Silva, Schut & Kortmulder 1985; Schut, De Silva & Kortmulder 1983.

Koenraad Kortmulder, May 2020.