Based on questionnaires conducted in 1992, the Batang Kayan and the Samunsam areas were identified as localities where arowana fish was frequently found in the 1980's, some measuring to 2 feet in total length. A sudden profitable trade in arowana in the mid 1980's had fish entrepreneur scavanging the areas for the fish, resulting in its decline in population.
After acquiring the fullest possible understanding of the habitats to be surveyed and the habits of the fish to be sampled, two factors determine the survey methods to be adopted:
- Only fishes in the adult stage need to be inventoried.
- Arowana (Scleropages formosus) need to be captured, possibly alive, for future captive breeding studies.
The physical parameters like oxygen content, slightly acidic standing water and secluded habitats have all the necessary ingredients of arowana's habitat. In the Arowana survey, the dipnet method is adopted. Dipnet is a form of active netting where fishes captured are required to be kept alive. This is implemented during the nocturnal hours (with the aid of headlamps) because, during the night, the arowana can be detected by their reddish eyeshine. The best months for the survey would be in September and October, highly possible to be the arowana breeding season and its biology had been known to breed in the upper reaches of a river.
Both Batang Kayan and Samunsam River had been positively identified as arowana's habitat. In the future, more rivers of Sarawak will be surveyed and a complete population distribution list will be compiled.
