Pak Sabah, Terengganu, Malaysia
ON the morning of Feb 11, fish farm operators in Tanjung Kupang, Johor, woke up to the ghastly sight of fish floating belly up in their pens in the Straits of Johor. In the days that followed, the fish kept dying.
The fish kill lasted two weeks, at the end of which commercially valuable stocks of snappers, estuary cods, seabass and threadfins in some nine farms were wiped out. One operator reported losses of RM150,000.
The mass mortality has since been blamed on a harmful algal bloom (HAB), or what is commonly referred to as red tide, a sudden population explosion of a toxin-producing microalgae.
While HABs are not often reported in Peninsular Malaysia, Sabah is no stranger to the phenomenon. Its first HAB was reported in 1976 and this has been a fairly annual occurrence since. In January and February last year, shellfish poisoning claimed three lives and over 40 people fell ill in Sepanggar and Inanam, both near Kota Kinabalu, in the state’s worst case of HAB.
In fact, the Sabah Fisheries Department has not lifted its red tide alert which it had issued in October 2011. In January, following the sighting of reddish-brown waters off Kota Kinabalu, director Rayner Stuel Galid said the red tide warning was still in effect and the toxins which were detected for eight months of last year continued to be seen from Tuaran to Kuala Penyu.
These incidents of HABs may be signs of what’s to come. According to Universiti Malaya marine ecologist Dr Lim Po Teen, HABs are occurring more frequently and in more locations over the past decade, and involve previously unknown species.
In the Tanjung Kupang case, the offensive microalgae was identified as Karlodinium australe, which caught scientists by surprise. “This is the first time we are seeing a bloom of this species, which has never been reported as toxic,” says Dr Leaw Chui Pin, a marine molecular biologist who has worked on harmful microalgae for 14 years.