Birdwatchers are happy to just report that such and such a species of birds had been seen fishing. They are generally not interested in what species the birds take. You cannot blame them. After all birders are not biologists. And just catching a glimpse of a bird swooping down on a fish with the help of a pair of binoculars will not allow for the fish to be identified to specific or even generic level.
Not now. A growing band of bird photographers that has been roaming our countryside has brought back excellent images of birds fishing that allow for the fish to be identified.
In this posting we are highlighting the species of fish that the Little Tern (Sterna albifrons) takes from the freshwater reservoir in Kranji. This is only possible through the excellent photography of Chan Yoke Meng. Three species of freshwater fish have been identified through the courtesy of Dr Khoo Hong Woo, formerly with the then Department of Zoology, National University of Singapore.
The giant snakehead or toman (Channa micropeltes), one of the largest of the world’s snakeheads, is cultured in our reservoirs and fish ponds as a food fish. The fish, held firmly between the beak of the juvenile shown in the image above is actually a young giant snakehead. These young fish gather in small, tight shoal near their parents and are thus easily predated by the Little Terns.
The glass fish (Chanda spp.) are easily identified as the body is translucent. Found in brackish and saline water near the coast, several species are also found in freshwater. They have been known to occur in our reservoirs, probably deliberately introduced. These are a favourite aquarium fish and some are artificially coloured through the injection of dyes.
The common tilapia (Oreochromis mossambicus, previously called Tilapia mossambicus) is not native to this region. Introduced as an aquaculture fish, it is popularly served in restaurants. This tilapia is common in our reservoirs. The fish taken by the Little Tern in the picture is a juvenile common tilapia.
Images of Little Tern with giant snakehead (top), glass fish (middle) and tilapia (bottom) by Chan Yoke Meng. Fish identification by Khoo Hong Woo.