Walrus crossbow graphic

Image showing how tissue samples were collected from Pacific walrus during a USFWS and USGS scientific research cruise in the Northern Bering and Chukchi seas to determine annual survival and population abundance.  Tissue samples are collected from walrus hauled-out on sea ice using biopsy darts launched from a crossbow. The darts punch a section of skin and fat that is about 1/4 of-an-inch in diameter. Darts are connected to floats so that the samples can be retrieved with minimal disturbance to the walrus.  Copyright Image by Heather McFarland in McFarland, H. R. (2022). Climate change and walrus. Bering Science: Spring 2022 Bering Region Ocean Update, Prewitt, J. and H. R. McFarland, editors.www.beringregionoceandata.org