Comparative efficacy of trash fish versus compounded commercial feeds in cage aquaculture of Asian seabass (Lates calcarifer) (Bloch) and tiger grouper (Epinephelus fuscoguttatus) (Forsska ˚ l) Paiboon Bunlipatanon 1 , Narin Songseechan 2 , Hassanai Kongkeo 3 , Nigel W Abery 3 & Sena S De Silva 3,4 1 Krabi Coastal Fisheries Research and Development Centre, Muang District, Krabi, Thailand 2 Phuket Coastal Fisheries Research and Development Centre, Thalang District, Phuket, Thailand 3 Network of Aquaculture Centres in Asia-Pacific (NACA), Bangkok, Thailand 4 School of Life & Environmental Sciences, Deakin University, Warrnambool, Victoria, Australia Correspondence: S S De Silva, School of Life & Environmental Sciences, Deakin University, Warrnambool, Victoria 3280, Australia. E-mail: sena.desilva@deakin.edu.au Abstract Trash fish/low valued fish is still the most com- monly used feed in marine cage culture in Asia. Use of trash fish is controversial with regard to the sustainability of the farming practices, and related issues on environmental degradation. In this study, the results of farm based trials on Asian seabass (Lates calcarifer) and tiger grouper (Epi- nephelus fuscoguttatus) to evaluate the efficacies of the use of commercial pellet feed in comparison to trash fish/low valued fish in marine cages in Thai- land are presented. In spite of the variations observed in each of the farm sites, the results indicate that the overall growth performances and fish survival rates between the two feed types were similar, for both species. However, better cost- benefit and resource use were recorded for fish reared on trash fish/low valued fish. No significant differences were observed in water quality parame- ters, dissolved oxygen, transparency and ammonia, between sites where pellet or trash fish were used, inside and outside the cages and for both species. The results of the present study are discussed in the light of the current controversies on the use of trash fish/low valued fish in marine cage culture. Keywords: Trash fish, commercial pellet feed, water quality, environment, seabass, grouper Introduction Aquaculture currently accounts for nearly 50% of the global seafood consumption, with Asia being the epicentre of aquaculture production, contribut- ing in excess of 85% to the global output (Subasinghe, Soto & Jia 2009). In the Asian region the fastest growing sub-sector is marine aquacul- ture, with an increasing emphasis on species such as Asian seabass (Lates calcarifer) (Bloch) and groupers (Family Epinephalidae), amongst others. These are all high valued species, most of which also cater to the lucrative and growing live food fish restaurant trade (LFFRT) in South East Asia concentrated in Hong Kong, Singapore, Southern China and Taiwan (Pawiro 2005; Nguyen, Davy, Rimmer & Silva 2009). Cage culture is the most predominant form of mariculture in the Asia-Pacific (Halwart, Soto & Arthur 2007; Liao & Lean ˜o 2008), and the emphasis on the cultured species and the nature, the intensity and scale of the culture operations differ from country to country (Kongkeo, Wayne, Murdjani, Bunliptanon & Chien 2010). However, the three main common denominators recogniz- able in mariculture practices across the entire region are that (i) the great bulk of mariculture is practised in cages in enclosed bays and sheltered coastal areas, (ii) are often small scale, farmer owned/leased, operated and managed and (iii) tra- © 2012 Blackwell Publishing Ltd 1 Aquaculture Research, 2012, 1–16 doi: 10.1111/j.1365-2109.2012.03234.x