Table 1.

Results of the best-fit linear mixed-effect model performed on (a) specific growth rate (SGR) in height, (b) SGR in length, and (c) SGR in weight as response variables. Model selection is reported in electronic supplementary material, tables S5A, S6A, and S7A. H_i, L_i, and W_i are the initial fish measurements at the start of the experiment, treatment is the light treatment (control versus ALAN), and site is field site. Exposure period refers to the two periods of treatment exposure (i.e. 0–15 months and 15–20.5 months). mR² is the marginal R², which describes the proportion of variance explained by the fixed factors alone. cR² is the conditional R², which describes the proportion of variance explained by both fixed and random factors. Significant data are shown in italics.

fixed effects	estimate	s.e.	d.f.	t-value	p-value	mR2	cR2
(a) SGR in height
intercept	0.2641	0.019	24.52	13.472	<0.001	0.906	0.963
log(Hi)	−0.2172	0.013	25.22	−16.490	<0.001
treatment (ALAN)	−0.0309	0.014	18.21	−2.260	0.036
2nd exposure period	0.0758	0.020	17.09	3.752	<0.001
site 2	0.0325	0.019	22.52	1.691	0.105
site 3	−0.0263	0.023	23.31	−1.162	0.257
2nd exposure period * site 2	−0.0433	0.019	13.92	−2.169	0.048
2nd exposure period * site 3	−0.0168	0.025	14.03	−0.661	0.519
(b) SGR in length
intercept	0.4671	0.033	25.90	14.093	<0.001	0.846	0.888
log(Li)	−0.2050	0.017	29.08	−11.728	<0.001
treatment (ALAN)	−0.0161	0.014	19.23	−1.184	0.251
exposure period	0.0515	0.014	26.66	3.796	<0.001
site 2	0.0079	0.017	18.20	0.455	0.655
site 3	−0.0333	0.021	18.78	−1.569	0.133
(c) SGR in weight
intercept	−0.3961	0.597	30.0	−0.664	0.512	0.397	0.397
log(Wi)	−0.7070	0.189	30.0	−3.723	<0.001
treatment (ALAN)	−0.7874	0.426	30.0	−1.850	0.074
exposure period	0.8427	0.440	30.0	1.914	0.065
site 2	−0.3848	0.541	30.0	−0.722	0.482
site 3	−0.2458	0.668	30.0	−0.368	0.716