Comparing diet composition from prey remains and fecal samples

• Main Authors: Brad Hanson, Ice Emmons, Michael Ford
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Killer Whale; Killer whale
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.296.4390; http://essa.com/wp-content/uploads/Hanson-Comparing-diet-composition-from-prey-remains-and-fecal-samples.pdf

DRAFT Document – all unpublished results should be considered preliminary. Please do not cite without permission of the authors. Panel Requests: Comparison of diets determined from fecal samples and prey remains (scales and tissue). Data from Puget Sound were presented by NMFS at the workshop; this presentation suggested that a proper comparison may already have been done. Such an analysis would help to assess the reliability of interpreting diet from floating scales and tissues. We have primarily used prey remains to characterize the southern resident killer whale diet composition. We are also in the process of conducting analyses to estimate prey composition from fecal samples. Prey remains: We have estimated the diet composition from prey remains by summing all of the prey samples and dividing the number of samples from each species by the total number of samples. In particular, if Xi represents the number of unique samples of species i in the prey samples, the proportion of species i in the diet was estimated to be X