| Situk and Mountain lakes, Yakutat, Alaska are active salmon spawning lakes that economically support the city of Yakutat. Little is known about the formation of the two lakes and the history of subsequent fluctuations of salmon abundance in this glacially dynamic region. 210Pb and 14C dates obtained from sediment cores, and basal 14C dates on two muskegs located between the two Holocene terminal moraines suggest a retreat of Hubbard Glacier from the outer moraine and formation of the lakes ~1400 cal AD during an early phase of the Little Ice Age (LIA). Physical properties and stable isotopes indicate a period of high suspended sediment load, inferred to result from glacial runoff from Russell Fiord into Situk and Mountain lakes from Hubbard Glacier, erosion of periglacial sediment deposited during the advances and retreats of Hubbard Glacier, and/or from local glaciers within the Mountain Lake watershed. Regardless of source, such influence only recently subsided, at the end of the Little Ice Age. Since ~1750 AD, the lakes turned into clear-water systems that ultimately supported higher abundances of sockeye salmon. Sedimentary δ15N remained at a base level state until measurable enrichment beginning ~1750 AD and increased, peaking in the late 1800’s AD (sedimentary δ15N of 7‰). Following this peak, sedimentary δ15N declined to its current level of 3.2‰. These data show that under natural conditions, salmon abundances increased until the development of a salmon cannery in 1903 AD, when salmon abundance subsequently decreased.Keywords: Oncorhynchus nerka, Sockeye salmon, Stable isotope analysis, Pacific decadal oscillation, Little Ice Age |