Dear colleagues,
We are happy to sharethe publication of our paper:
Insights into the trophic ecology of white-beaked dolphins
/Lagenorhynchus albirostris/ and harbour porpoises /Phocoena
phocoena/ in Iceland
Filipa I. P. Samarra, Asunción Borrell, Anna Selbmann, Sverrir D.
Halldórson, Christophe Pampoulie, Valérie Chosson, Thorvaldur
Gunnlaugsson, Guðjón M. Sigurðsson, Alex Aguilar, Gísli A. Víkingsson
MEPS 702: 139-152
The article can be accessed at
https://www.int-res.com/abstracts/meps/v702/p139-152/
<https://www.int-res.com/abstracts/meps/v702/p139-152/>or you can
contact me directly for a PDF of the paper (fipsama...@gmail.com)
Abstract
Sympatric organisms can avoid competition by occupying different
ecological niches, a mechanism known as niche partitioning. In Iceland,
white-beaked dolphins /Lagenorhynchus albirostris/ and harbour porpoises
/Phocoena phocoena/ are the most common small cetaceans observed but
their trophic ecology remains understudied, including the potential for
resource competition. In this study, we measured δ^15 N and δ^13 C
values from white-beaked dolphin (n = 28) and harbour porpoise (n = 29)
muscle samples collected over a 33 yr period (1987-2019) to compare
isotopic niche width and overlap of both species, as well as diet
composition. We also tested for within-species effects of sex, age
class, body length, year of sampling and origin (bycatch vs. stranding)
on the δ^13 C and δ^15 N values. Intra-species variations included
differences between stranded and bycaught white-beaked dolphins and
ontogenetic variations in both species, but further studies are
necessary to investigate the factors that might explain these results.
Inter-species comparisons showed that harbour porpoises and white-beaked
dolphins had non-overlapping isotopic niches, with harbour porpoises
exhibiting smaller niche widths (corrected standard ellipse area, SEA_c
: 1.25 vs. 2.13‰^2 ). While white-beaked dolphins had a broader diet,
composed primarily of gadoids but with contributions of other fish
species, harbour porpoises fed almost exclusively on capelin /Mallotus
villosus/, suggesting niche segregation and width is largely maintained
by targeting different prey resources. Both species also showed no
long-term changes in trophic ecology, despite recent ecosystem changes
in this region, possibly a result of adapting to spatial changes in prey
distribution or shifts to other prey at similar trophic levels.
This article is dedicated to the memory of our co-author, colleague and
friend Dr. Gísli Víkingsson, who was instrumental in developing
cetacean research in Iceland.
Bestregards,
Filipa Samarra
--
Filipa Samarra
ResearchSpecialist/Sérfræðingur
University of Iceland's Institute of Research Centres/Stofnun
rannsóknasetra Háskóla Íslands
Ægisgata 2
900 Vestmannaeyjar, Iceland
ORCID: https://orcid.org/0000-0002-9909-0565
ResearchGate: https://www.researchgate.net/profile/Filipa_Samarra
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www.icelandic-orcas.com
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