Table 2.

Linear mixed effect model results for cod (n = 8) heart rate, swimming depth, body acceleration and distance from the centre of the sea cage (origo). Correlations are given between sound measurements and heart rate, body acceleration and depth. Separate models were tested for each sound measurement

Response variable	Model type	Delta AICcnull	Random forest percent variance explained (%)	Covariate name	Coefficient	SE	P
1) Heart rate	All covariates	2412	8.6	Swimming depth	0.270	0.110	0.012
				Distance to origo	−0.002	0.040	0.96
				Body temperature	0.015	0.200	0.94
	Behavioural factors excluded	9945	2.8	Body temperature	−10.700	0.970	<0.001
				AELsp	−1.080	0.100	<0.001
				AELcum	−0.027	0.001	0.048
2) Swimming depth	All covariates	1669	51.9	Body temperature	−0.560	0.085	<0.001
				Distance to origo	−0.270	0.014	<0.001
				Heart rate	0.069	0.020	<0.001
	Behavioural factors excluded	1702	33.1	Body temperature	−1.300	0.130	<0.001
				SELcum	0.002	0.021	0.93
				SELsp	−0.018	0.022	0.43
3) Body acceleration	All covariates		No good models and all covariates were P > 0.05
	Behavioural factors excluded		No good models and all covariates were P > 0.05
4) Distance from origo	All covariates	1269	45.7	Swimming depth	−1.300	0.110	<0.01
				SELcum	0.033	0.026	0.21
				Heart rate	−0.190	0.068	<0.01
	Behavioural factors excluded	1827	25.1	Body temperature	2.000	0.360	<0.001
				Zero to peak sound pressure level (P0-pk)	−0.060	0.052	0.26
				SELcum	0.100	0.048	0.031