Growth reaction norms of domesticated, wild and hybrid Atlantic salmon families in response to differing social and physical environments

Table 3 Summary of the LME models testing for differences in weight(log ₁₀ ) at termination, experiment I and II

Experiment	Model	Social or physical treatment	Fixed effect	DFn	DFd	Sum Sq	F	P
I	1	Mixed-strain vs. single-strain	Social treatment	1	148	0.9	28.3	<0.0001
			Origin	2	147	7.4	114.7	<0.0001
			Social treatment x origin¹	2	147	0.3	4.8	0.017
II	2.1	Hatchery control vs. restricted hatchery	Physical treatment	1	425	6.1	157.9	<0.0001
			Origin	2	424	9.1	117.7	<0.0001
			Physical treatment x origin²	2	424	0.9	11.5	<0.0001
	2.2	Hatchery control vs. restricted semi-natural	Physical treatment	1	35	2.0	99.2	<0.0001
			Origin	2	34	4.7	118.0	<0.0001
			Physical treatment x origin	2	34	1.3	32.3	<0.0001
	2.3	Restricted hatchery vs. restricted semi-natural	Physical treatment	1	35	0.6	11.0	0.0009
		Restricted hatchery vs. restricted semi-natural	Origin	2	34	4.6	43.7	<0.0001

F-statistics of the selected linear mixed effects models, fitted using ML estimation. DFn; numerator degrees of freedom. DFd; denominator degrees of freedom. Differences in body weight at termination between salmon of farmed, hybrid or wild origin were investigated by re-running the selected models while excluding one of the three genetic origins at a time, while multiple comparisons were corrected for by the Bonferroni correction, giving an adjusted significance level of 0.017. ¹ The interaction treatment x origin were not significant in the farmed and wild salmon (DFn = 1, DFd = 148, Sum Sq = 0.0006, F = 0.015, P = 1). ² The interaction treatment x origin were not significant in the hybrid and farmed salmon (DFn = 1, DFd = 425, Sum Sq = 0.0014, F = 0.036, P = 1).

ISSN: 2730-7182