Breeding spree by clam, Pearl Spot

Post flood, level of dissolved oxygen has increased

Last year’s great deluge caused unparalleled devastation, but the floods have turned out to be a blessing in disguise for clam and fish species in the Vembanad Lake.

A post-flood evaluation conducted under the aegis of International Research and Training Centre for Below Sea level Farming (IRTCBSF) revealed that the production of black clam (Villorita cyprinoides) has increased significantly. The catch of Pearl Spot (Karimeen) from the waterbody also “improved” after the floods.

While the average annual clam landing before the deluge stood at 25,000 tonnes, in the flood year the production touched 30,000 tonnes. “The flood was a disaster for human beings, but the post-flood period is a festival period for some species in the Vembanad Lake. The floodwaters have cleaned the lake. Post-flood, level of dissolved oxygen increased and the water became more transparent, which helped the species to breed. A decrease in turbidity is benefiting Pearl Spot the most. Although Pearl Spot landing has not increased like black clam, there is a significant improvement in post-flood months,” K.G. Padmakumar, Director, IRTCBSF, told The Hindu.

Prawns affected

The study, however, finds that the floods have adversely impacted the production of Kuttanandan Konchu (Macrobrachium rosenbergii). Prawns with “poor swimming ability” were washed away downstream in the flash floods, Mr. Padmakumar added.

The black clam, a bottom-dwelling species, is a source of livelihood for thousands and plays an important role in ensuring the sustainability of the lake ecosystem. Black clam contributes to 70% of production of fisheries in Vembanad and 60% of India’s clam production takes place in this backwater. Vembanad, acclaimed as an ‘inland fish basket’, witnessed a drastic decline in inland fishery resources in recent years owing to several anthropogenic activities.

Mr. Padmakumar suggested that the government impose a ban on fishing of inland species during their breeding period. “To maintain a healthy population of different fish species, we need to impose a ban like trawling ban in inland waters during a certain period. A fish passage should also be created across the Vemaband Lake at Thanneermukkom,” he added.

Source: Read Full Article