Freshwater performance of triploid Atlantic salmon (Salmo salar) in New Brunswick aquaculture

The use of ploidy manipulation to produce sterile salmon has been investigated since the mid-1970s. Today, the techniques for producing triploids are well documented. In this study pressure shock techniques were employed to produce triploid Atlantic salmon on a commercial scale, and performance differences between triploids and diploids were assessed. A new 2.5 1 pressure vessel was designed and used to produce approximately 36 000 triploid salmon during the 1992 spawning season. This vessel was highly successful in inducing triploidy, as determined by flow cytometry, Performance was based on survival and growth, which were monitored from the egg stage until the time of smelting, There were no significant differences in cumulative survival throughout the experiment. During April, May and June of 1993, triploids were significantly smaller than their diploid counterparts (P < 0.05), However, from July 1993 until February 1994 there were no differences in size. In February 1994 the smelting rate was determined by classifying those fish greater than 13 cm as smelt. The success rates were 86% and 88% for triploids and diploids, respectively.