Document Type
Article
Publication Date
9-15-2018
Keywords
Diet analysis, DNA metabarcoding, Marine mammals, Predator prey interactions, Sex identification
Abstract
Sex-specific diet information is important in the determination of predator impacts on prey populations. Unfortunately, the diet of males and females can be difficult to describe, particularly when they are marine predators. We combined two molecular techniques to describe haul-out use and prey preferences of male and female harbor seals (Phoca vitulina) from Comox and Cowichan Bay (Canada) during 2012-2013. DNA metabarcoding quantified the diet proportions comprised of prey species in harbor seal scat, and qPCR determined the sex of the individual that deposited each scat. Using 287 female and 260 male samples, we compared the monthly sex ratio with GLMs and analyzed prey consumption relative to sex, season, site, and year with PERMANOVA. The sex ratio between monthly samples differed widely in both years (range = 12%-79% males) and showed different patterns at each haul-out site. Male and female diet differed across both years and sites: Females consumed a high proportion of demersal fish species while males consumed more salmonid species. Diet composition was related to both sex and season (PERMANOVA: R 2 = 27%, p < 0.001; R 2 = 24%, p < 0.001, respectively) and their interaction (PERMANOVA: R 2 = 11%, p < 0.001). Diet differences between males and females were consistent across site and year, suggesting fundamental foraging differences, including that males may have a larger impact on salmonids than females. Our novel combination of techniques allowed for both prey taxonomic and spatiotemporal resolution unprecedented in marine predators.
Publication Title
Ecology and Evolution
Volume
8
Issue
19
First Page
9889
Last Page
9905
DOI
10.1002/ece3.4474
Required Publisher's Statement
Copyright 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
Recommended Citation
Schwarz, Dietmar; Spitzer, Sara M.; Thomas, Austen C.; Kohnert, Christa M.; Keates, Theresa R.; and Acevedo-Gutiérrez, Alejandro, "Large-scale Molecular Diet Analysis in a Generalist Marine Mammal Reveals Male Preference for Prey of Conservation Concern" (2018). Biology Faculty and Staff Publications. 58.
https://cedar.wwu.edu/biology_facpubs/58
Subjects - Topical (LCSH)
Marine mammals--Gender; Diet--Analysis; Forage fishes
Genre/Form
articles
Type
Text
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Language
English
Format
application/pdf
