On Saturday morning, about 70 researchers, students, fishermen and local people will set out on boats from the banks of Vellayani Lake near here on a mission to study the diversity of aquatic life.

The Department of Aquatic Biology and Fisheries, University of Kerala, in association with the Agency for Development of Aquaculture, Kerala (ADAK), is organising a participatory fish census of the freshwater lake.

The census, the first such exercise undertaken in Vellayani Lake, includes a survey of the whole lake. As many as five teams travelling boats will scan different zones of the lake simultaneously and record the diversity and abundance of fish and other aquatic fauna.

According to A. Biju Kumar, head of the department, the status of fishery resources of the lake has not been well-documented in the recent past even though 41 species of freshwater fishes have been recorded from the lake. Many species such as ‘Aattu Vala” (Wallago attu) and Crocodile-tooth pipefish (Microphis cunculus) once abundant in the lake have not been recorded in the recent past, while others such as ‘Kaari’ (Clarias dussumieri), eels (Anguilla bengalensis, Anguilla bicolor), zig-zag eel (Mastacembelus armatus), Varal (Channa marulius) recorded sharp decline in population.

The second largest freshwater lake in Kerala, Vellayani faces several threats from human activities, impacting its rich biodiversity. In 2009, ADAK had joined hands with the Directorate of Environment and Climate Change to launch a fish stock enhancement programme, under which three Indian major carps (Catla, Rohu and Mrigal) and the giant freshwater prawn (Macrobrachium rosenbergii) were introduced.

The status of fishery resources after the stock enhancement programme will be analysed during the census, Dr. Kumar said in a pressnote.