Herklotsichthys quadrimaculatus Korumburuwa in the stilt fishery in Southern Sri Lanka: Are they really poisonous?

Abstract

Stilt fishing is a unique fish catching method confined only to southern coast of Sri Lanka from Galle to Matara. Stilt fishermen sitting on a cross bar called “Petta” tied to vertical pole planted in the reef and carrying out rod and line fishing are a Sri Lankan icon that attracts local and foreign tourists’ attention. This small-scale, seasonal fishing method has a long history and fishers use traditional ecological knowledge for their fishing activities (Deepananda et al. 2016). Two fish species, big eye scad ( Selar crumenophthamus ) locally known as Esgedi bolla and bluestripe herring ( Herklotsichthys quadrimaculatus ) locally known as Korumburuwa are caught by this fishing method. Of the two species, Korumburuwa is fished throughout the fishing season which commences from early June with the onset of southwest monsoon and continues until February/March of the following year. Due to freshness of the fish that can be bought at affordable price, most buyers prefer purchasing Korumburuwa at the place they are fished traditionally called as Rendapola. However, there is a traditional belief among some consumers that eating Korumburuwa causes some toxic effect leading to vomiting, dizziness and sometimes fainting among those who consume this species, and also deaths of domestic animals such as cats. These beliefs have detrimental impacts on the marketing of H. quadrimaculatus caught in stilt fishing. Such widespread beliefs may have been propagated rapidly among consumers through electronic mass media. For instance, recent media reports on fish poisoning by Auxis thazard in Muttur and observation of bioluminescence in Decapterus ruselli in Weligama seriously impacted consumption of fish by general public. This communication reports the findings of a short-term study on gut contents of H. quadrimaculatus , which was carried out to investigate the root cause of the people’s beliefs that Korumburuwa is poisonous.