Table 1.

Latitude of river mouth (°N), sampling dates, number of fish (n) and mean fresh mass with standard deviation (mass ± s.d.) for rivers included in the latitudinal gradient of winter lipid-depletion rates. Also given are estimated intercept (β₀), slope (β₁) and r² from least-square regressions between lipid mass and lipid-free dry mass (log_e lipid mass = β₀ + β₁ log_e lipid-free mass) used to size-standardize lipid content to a common mean lipid-free dry mass of 0.96 (4.04 g fresh mass). All p-values < 0.002.

river	°N	sampling dates	n	mass ± s.d.	β0	β1	r2
Børselva	70.2	05/09/2007	55	3.58 (2.51)	−2.68	0.71	0.61
		07/05/2008	56	4.60 (2.79)	−2.40	0.86	0.81
Lakselva	70.5	06/09/2007	41	4.55 (3.55)	−1.83	1.30	0.96
		06/05/2008	37	4.67 (2.44)	−2.55	1.06	0.86
Russelva	70.4	05/09/2007	33	4.10 (2.62)	−1.70	0.82	0.86
		09/05/2008	40	7.31 (2.92)	−2.53	1.26	0.69
Neiden	69.4	12/09/2007	33	4.35 (3.79)	−2.70	1.14	0.93
		04/05/2008	45	4.89 (2.86)	−3.04	1.29	0.89
Tana	70.1	13/09/2007	48	3.13 (2.61)	−2.18	0.97	0.91
		03/05/2008	47	3.18 (2.56)	−2.98	0.59	0.60
Homla	63.2	03/10/2007	50	2.94 (2.67)	−2.79	1.42	0.87
		17/04/2008	50	3.35 (2.35)	−2.82	1.20	0.87
Stjørdalselva	63.3	29/09/2007	46	3.64 (2.67)	−2.19	1.04	0.84
		21/03/2008	43	3.30 (2.74)	−2.77	0.89	0.88
Gaula	63.2	10/10/2007	56	3.05 (2.48)	−2.84	1.05	0.83
		22/05/2008	53	3.53 (2.77)	−2.75	0.96	0.97
Surna	63.0	13/10/2007	82	5.00 (2.71)	−2.44	0.87	0.69
		29/03/2008	73	3.60 (2.44)	−3.27	0.70	0.44
Figgjo	58.5	20/09/2007	30	4.70 (3.98)	−1.92	1.29	0.98
		26/03/2008	30	3.70 (2.88)	−3.28	1.25	0.80
Håelva	58.4	19/09/2007	32	4.20 (2.88)	−2.68	1.53	0.96
		26/03/2008	26	6.21 (2.97)	−2.92	1.09	0.59
Kvassheim	58.4	19/09/2007	29	3.76 (2.48)	−2.36	1.41	0.89
		26/03/2008	28	4.35 (1.84)	−2.70	1.08	0.82
Ogna	58.3	19/09/2007	38	4.07 (3.64)	−2.63	1.17	0.88
		26/03/2008	29	4.95 (3.03)	−3.38	0.81	0.34