[MARMAM] New publication: male preference for salmon in harbor seals

Alejandro Acevedo-Gutierrez Alejandro.Acevedo-Gutierrez at wwu.edu
Tue Sep 18 08:10:59 PDT 2018

Dear all

My colleagues and I are pleased to announce the publication of the paper  "Large scale molecular diet analysis in a generalist marine mammal reveals male preference for prey of conservation concern".

Schwarz, D., Spitzer, S., Thomas, A., Kohnert, C., Keates, T. & Acevedo-Gutiérrez, A. 2018. Large scale molecular diet analysis in a generalist marine mammal reveals male preference for prey of conservation concern. Ecology and Evolution 2018, 1-17.

DOI: 10.1002/ece3.4474.


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  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: R2 = 27%, p <0.001; R2 = 24%, p  <  0.001,  respectively)  and  their  interaction  (PERMANOVA: R2 = 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.

The paper is open access and available to read or download in the following link:  https://onlinelibrary.wiley.com/doi/epdf/10.1002/ece3.4474

Feel free to contact me if you have any questions.



Alejandro Acevedo-Gutierrez
Professor in Biology and Science Education
Western Washington University

Alejandro.Acevedo-Gutierrez at wwu.edu
acevedo at biol.wwu.edu

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