Distribution of short-finned squid Illex argentinus (Cephalopoda: Ommastrephidae) inferred from the diets of Southern Ocean albatrosses using stable isotope analyses

Seco, José; Daneri, Gustavo A.; Ceia, Filipe R.; Vieira, Rui Pedro; Hill, Simeon L. ORCID: https://orcid.org/0000-0003-1441-8769; Xavier, Jose Carlos ORCID: https://orcid.org/0000-0002-9621-6660. 2016 Distribution of short-finned squid Illex argentinus (Cephalopoda: Ommastrephidae) inferred from the diets of Southern Ocean albatrosses using stable isotope analyses. Journal of the Marine Biological Association of the United Kingdom, 96 (6). 1211-1215. https://doi.org/10.1017/S0025315415000752

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	Text This article has been accepted for publication and will appear in a revised form in the Journal of the Marine Biological Association of the United Kingdom, published by Cambridge University Press. Copyright Marine Biological Association of the United Kingdom. Seco et al 2016 manuscript_with_figures_Illex_Final.docx - Accepted Version Download (295kB)

Abstract/Summary

The diets of marine predators are a potential source of information about range shifts in their prey. For example, the short-finned squid Illex argentinus, a commercially fished species on the Patagonian Shelf in the South Atlantic, has been reported in the diet of grey-headed, Thalassarche chrysostoma; black-browed, T. melanophris; and wandering, Diomedea exulans, albatrosses breeding at Bird Island, South Georgia (54°S 28°W) in the Southern Ocean. Tracking data suggest that these birds may feed on I. argentinus while foraging in Southern Ocean waters during their breeding season. This led to the hypothesis that I. argentinus may occur south of the Antarctic Polar Front. To test this hypothesis, we used stable isotope analyses to assess the origin of I. argentinus. We compared I. argentinus beaks from the diets of the three albatross species with beaks of cephalopod species endemic to the Patagonian Shelf and others from the Southern Ocean. Our results show that I. argentinus from the diet of albatrosses at Bird Island have δ13C values in the range −18.77 to −15.28‰. This is consistent with δ13C values for Octopus tehuelchus, a typical species from the Patagonian Shelf. In contrast, Alluroteuthis antarcticus, a Southern Ocean squid, has typically Antarctic δ13C in the range −25.46 to −18.61‰. This suggests that I. argentinus originated from warmer waters of the Patagonian Shelf region. It is more likely that the albatross species obtained I. argentinus by foraging in the Patagonian Shelf region than that I. argentinus naturally occurs south of the Antarctic Polar Front.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1017/S0025315415000752
Programmes:	BAS Programmes > BAS Programmes 2015 > Ecosystems
ISSN:	0025-3154
Additional Keywords:	Trophic interactions, δ13C, Thalassarche chrysostoma, Thalassarche melanophris, Diomeda exulans, Patagonia Shelf, Bird Island
Date made live:	15 Jun 2015 10:55 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/511036

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