Melting of the Greenland Ice Sheet (GrIS) is accelerating and will contribute signifi-cantly to global sea level rise during the 21st century. Instrumental data on GrIS melting only cover the last few decades, and proxy data extending our knowledge into5 the past are vital for validating models predicting the influence of ongoing climatechange. We investigated a potential meltwater proxy in Godthabsfjord (West Green- ˚land), where glacier meltwater causes seasonal excursions with lower oxygen isotopewater (δ18Ow) values and salinity. The blue mussel (Mytilus edulis) potentially recordsthese variations, because it precipitates its shell calcite in oxygen isotopic equilibrium10 with ambient seawater. As M. edulis shells are known to occur in raised shorelinesand kitchen middens from previous Holocene warm periods, this species may be idealin reconstructing past meltwater dynamics. We investigate its potential as a palaeomeltwater proxy. First, we confirmed that M. edulis shell calcite oxygen isotope (δ18Oc)values are in equilibrium with ambient water and generally reflect meltwater conditions.Subsequently we investigated if this species recorded the full range of δ1815 Ow valuesoccurring during the years 2007 to 2010. Results show that δ18Ow values were notrecorded at very low salinities (<∼ 19), because the mussels appear to cease growing.This implies that M. edulis δ18Oc values are suitable in reconstructing past meltwater amounts in most cases, but care has to be taken that shells are collected not too20 close to a glacier, but rather in the mid region or mouth of the fjord. The focus of futureresearch will expand on the geographical and temporal range of the shell measurements by sampling mussels in other fjords in Greenland along a south-north gradient,and by sampling shells from raised shorelines and kitchen middens from prehistoricsettlements in Greenland.