Rise Of Parrot Fish In Gulf Of Mannar

The survey was done between April and June this year, and researchers say that the increase in numbers is a result of the lockdown and the subsequent fishing ban. Average fish density was found to have increased by 22% – from 405 fish per 250 metre square area to 510 fish now in the same area in the Thoothukudi group of islands Vaan, Koswari, Kariyachalli, Vilanguchalli and Vilanguchalli Patch Reef area. 

The survey explored impact of meso (5 mm to 2.5 cm in size) and macro (>2.5 cm in size) plastics on the coastal area, the quality of marine water and assessed coral bleaching. While it noted a general increase in fish density, it focused specifically on parrotfish – a species of fish that has been known as the saviour of coral reefs, the populations of which have been depleting because of fishing and its export value

While temperatures continue to rise in the ocean (31.5 to 31.8 degree Celsius), a reminder of the climate crisis, the absence of trap-fishing and other fishing activities during the lockdown period in the reef area has increased the population of reef species, he concurs. In trap-fishing, fishermen set traps underwater in the reef areas to catch fish, causing severe damage to the corals. “Divers put the traps in between corals and tie them to nearby coral heads, directly damaging them in the process. Injured corals are prone to diseases, predation, etc. and may not recover from the injuries,” explains Dr Patterson.