Sea ice distribution and ice use by indigenous walrus hunters on St. Lawrence Island, Alaska

Abstract

The hunting success of St. Lawrence Island walrus hunters from Savoonga (Sivungaq) and Gambell (Sivuqaq) is studied in relation to weather and sea ice conditions for the period 1979-2008. Satellite remote-sensing data, including ice concentration fields from passive-microwave radiometer data, have been examined over the entire time series in conjunction with walrus harvest data from two community-level monitoring programs. Important information to aid with interpretation of these data sets was provided by the hunters themselves, in particular through a log of ice conditions and ice use by L. Apangalook, Sr., of Gambell. From these data, we determined which ice conditions (concentrations >0 and <30%) and which wind speeds (1-5 m s-1 at Savoonga and 5-9 m s-1 at Gambell), temperatures (-5 to +5°C), and visibility (>6 km) provide the most favorable conditions for the walrus hunt. The research demonstrated that at the local level, though not necessarily at the region-wide scale, the sea ice concentration anomaly is a very good predictor of the number of favorable hunting days. With the exception of 2007 (and to a lesser extent, 2008), negative anomalies (less ice or earlier onset of ice retreat) coincided with more favorable (Savoonga) or near-average (Gambell) hunting conditions, controlled mostly by access to ice-associated walrus. Ice access and temporal variability differ significantly between Savoonga and Gambell; in contrast with northern Alaska communities, St. Lawrence hunters were able to maintain typical levels of harvest success during the recent record - low ice years of 2007 and 2008. We discuss the potential value of data such as assembled here in assessing vulnerability and adaptation of Arctic communities depending on marine-mammal harvests to climate variability and change. © 2010 Springer Science+Business Media B.V.