The experiment was conducted at the Jitra Aquaculture Extension
Center of the Department of Fisheries, located at Kedah State of
Malaysia. From 2009 to 2012, four batches of experimental fish were
produced from the GIFT breeding program, one batch per year. The
four batches of experiments were named after the year when the fish
were stocked in the ponds. Batch 2012 was excluded because of high
mortality due to extreme weather conditions; see Khaw et al. (2015)
for details. The reproduction and selection methods used in the GIFT
breeding program are outlined in Ponzoni et al. (2005, 2010). Table 1
presents the abbreviations used in this paper.