BUHI, Camarines Sur, Oct. 22 (PNA) -- The rains dumped by Typhoon "Lando" resulted in the upswelling at the bottom of Lake Buhi, causing a fishkill that involved PHP14.5 million worth of cultured tilapia in fish cages, according to the Bureau of Fisheries and Aquatic Resources (BFAR) in Bicol.
BFAR Director Dennis Del Socorro said the fishkill that occurred on October 19 wasted an estimated 114 metric tons of cultured tilapia owned by 68 fish cage owners.
As the inclement weather condition dumped heavy rains into the lake, it stirred decaying matters at the lake bottom that caused the generation of ammonia and the depletion of oxygen content of the water, Del Socorro explained how the fishkill began and developed.
He said fishkill occurrences also happen during a long dry season when sudden downpour comes for consecutive days, followed by an abrupt change of weather to bright searing sun.
This disturbs the lake environment and causes fishkill like the one that happened in Lake Bato last year.
The biggest fishkill happened in Lake Buhi in October 2010 when 90 percent of 19,000 fish cages that were randomly erected across about 70 percent of the 1,650-ha lake area were affected, according to Ronilo Real, lake development officer.
Real said the losses then were estimated to reach PHP80 million and the cause was the overstocking and increased pollution of the lakewater.
This prompted the local government of Buhi to dismantle more than 3,000 fish cages to clear areas for navigation, communal fisheries fish sanctuary.
It was found out in a study conducted by BFAR Fish Health Section in 2010 that five fishkill incidents with total losses reaching PHP33 million in 1998 in Lake Buhi were caused by overstocking.
When the fishkill occurred in 2010, it said, the cause of the fishkill was that “the lake’s dissolved oxygen was very low; the ammonia nitrogen level was very high in 11 stations monitored in the lake and high toxic traces of hydrogen sulfide was also detected.”
Lake Buhi is the biggest lake in Bicol located in Buhi town in Camarines Sur where the smallest commercial fish, sinarapan (Mystichthys luzonensis), is found.(PNA) FFC/FGS/JME/CBD