Table S5.

Published δ¹³C and δ¹⁵N values on tissues from modern chum salmon and freshwater fish from central Alaska

Taxon	Alaskan Region	n	Original tissue	Original δ13C (‰)	Original δ15N (‰)	Adjusted δ13C (‰)*	Adjusted δ15N (‰)*	Source
Oncorhynchus keta (chum)	Central	4	Muscle	−20.3 ± 0.2	11.5 ± 0.5	−16.8	10.5	(80)
	South Central	39	Muscle†	−20.4 ± 1.0	10.6 ± 1.0	−16.9	9.6	(74)
	Southwest	23	Muscle‡	−21.9 ± 0.7	10.7 ± 0.9	−18.4	9.7	(71)
	Southwest	2	Bone collagen	na	11.6 ± 1.1	–	11.6	(75)
	Southeast	3	Muscle	−20.3 ± 0.3	11.6 ± 0.7	−16.8	10.6	(72)
	Southeast	25	Muscle	−20.3 ± 0.7	11.0 ± 1.2	−16.8	10.0	(73)
Freshwater fish
Nonsalmonids
Cottus cognatus (sculpin)	Central	47	Muscle	−28.5 ± 3.8	7.0 ± 1.6	−25.0	6.0	(80)
Lota lota (burbot)	Central	21	Muscle	−27.5 ± 2.4	12.1 ± 1.9	−24.0	11.1	(80)
Salmonids
Oncorhynchus mykiss (rainbow trout)	Central	11	Muscle	−23.0 ± 1.4	13.2 ± 1.6	−19.5	12.2	(80)
Salvelinus namaycush (lake trout)	Central	35	Muscle	−28.5 ± 3.8	12.3 ± 2.1	−25.0	11.3	(80)
Thymallus arcticus (Arctic grayling)	Central	34	Muscle	−29.0 ± 1.7	8.7 ± 0.5	−25.5	7.7	(81)
Thymallus arcticus (Arctic grayling)	Central	9	Muscle	−27.3 ± 3.1	10.0 ± 1.6	−23.8	9.0	(80)

^*Isotope values on modern fish tissue were adjusted for differences between tissue types and between ancient and modern tissues due to the Suess effect as follows (after ref. 69; see text for further details.): δ¹³C _{prehistoric fish tissue} = δ¹³C _{modern fish tissue} + 1‰; δ¹³C _{fish collagen} = δ¹³C _{fish muscle} + 2.5‰; δ¹⁵N _{fish collagen} = δ¹⁵N _{fish muscle} − 1‰.

^†Lipid extracted muscle.

^‡Lipid corrected muscle.