Four tissues, liver, gills, head kidney and intestine, were sampled April 28th 2006 from a total of 20 Atlantic salmon with an average body mass of 381 ± 85 g and body length 33.9 ± 2.6 cm (fork length, mean ± S.D .. Average condition factor (c.f. = weight/length-3) was 0.96 ± 0.10 (mean ± S.D .. Tissue samples were dissected out as fast as possible, and immediately frozen in liquefied nitrogen.
There were no significant differences in size and condition factor (mean 1.31 female; mean 1.33 male) or HSI (mean 1.66 female; mean 1.75 male) between treatment groups.
Size- and growth-related traits tend to be heritable in salmonids (mean h = 0.25 for size and growth rate, mean h = 0.23 for condition factor; Garcia de Leaniz et al. 2007; Carlson and Seamons 2008) and are thus likely to respond quickly to novel selection pressures during fish invasions.
The RPA variables (RPA Max, RPA Mean and RPA Std ) were all sensitive to the CONDITION factor during both flexion and extension.
At the end of the 30-days fasting period the mean body weight decreased to 121 g ± 5.5 and the condition factor to 1.3 ± 0.03.
The effects (p < 0.05) for the means of final weight, weight gain, apparent feed conversion and condition factor were observed for the analysis of productive performance.
For each family, means (with standard error) for weight, length and Fulton's condition factor are shown in Table 2.
The mean body weight of the trout was 132 g ± 6.0 and the condition factor was 1.6 ± 0.03 before fasting.
The mean values of fish total and standard body length, body and liver weight, Fultons condition factor, and hepatosomatic index did not show significant differences (Table 4).
Farmed, recent escapees and wild trout differed greatly in condition factor (F2, 237 = 4.380, P = 0.014), as farmed fish had a significantly higher condition factor (mean = 1.43, SE = 0.025) than wild fish (mean = 1.31, SE = 0.024; Post hoc Bonferroni adjusted P = 0.010), which did not differ from that of escapees (mean = 1.36, SE = 0.047; Post hoc Bonferroni adjusted P = 1.000).
