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Tissue, ontogenic and sex-related differences in δ13C and δ15N values of the oceanic squid Todarodes filippovae (Cephalopoda: Ommastrephidae)
Citation
Cherel, Y and Fontaine, C and Jackson, GD and Jackson, CH and Richard, PD, Tissue, ontogenic and sex-related differences in δ13C and δ15N values of the oceanic squid Todarodes filippovae (Cephalopoda: Ommastrephidae), Marine Biology, 156, (4) pp. 699-708. ISSN 0025-3162 (2009) [Refereed Article]
DOI: doi:10.1007/s00227-008-1121-x
Abstract
Stable isotopes are increasingly used in the
study of trophic interactions of many aquatic animals and
most recently cephalopods. To evaluate the application of
the method to squids, it is important to assess isotopic
diVerences among and within consumer tissues that may
confound the resolution of ecological relationships. Interand
intra-tissue isotopic variation was examined in 55 individuals
of the oceanic squid Todarodes Wlippovae that were
collected at the beginning of April 2000 in the southwestern
Indian Ocean (between 44°S, 76°E, and Saint Paul and
Amsterdam islands, 38°S, 78°E). Delipidated soft tissues
(mantle, arm, buccal mass, gill and reproductive organs)
showed small 13C and 15N diVerences, which were probably
tissue-speciWc. A lower carbon value was observed in
the digestive gland as a consequence of incomplete lipid
removal. Hard tissues, such as beaks and gladii, had lower
15N values than soft tissues, which can be explained by
the presence of chitin, a 15N-depleted molecule. Females
(n = 38) and males (n = 17) had identical 13C values, but
females showed higher 15N values than males. The diVerence
was size-related rather than sex-related, however, as
females were generally larger than males. A comparison of
similar-sized females and males produced identical nitrogen
values. These data suggest dietary shifts from lower to
higher trophic levels during growth, because 15N values of
large T. Wlippovae were much higher than that of small
specimens. As expected, nitrogen values of lower beaks
and gladii of large squids increased from the oldest to the
most recently formed region, reXecting the progressive
growth of chitinized tissues in parallel with dietary
changes. Sequential sampling along the growth increments
of squid beaks and gladii can likely be used to produce a
chronological record of dietary information throughout an
individual’s history.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Biological Sciences |
| Research Group: | Zoology |
| Research Field: | Animal Physiological Ecology |
| Objective Division: | Environment |
| Objective Group: | Flora, Fauna and Biodiversity |
| Objective Field: | Antarctic and Sub-Antarctic Flora, Fauna and Biodiversity |
| Author: | Jackson, GD (Dr George Jackson) |
| Author: | Jackson, CH (Mrs Christine Jackson) |
| ID Code: | 56146 |
| Year Published: | 2009 |
| Web of Science® Times Cited: | 31 |
| Deposited By: | IASOS |
| Deposited On: | 2009-03-27 |
| Last Modified: | 2011-07-27 |
| Downloads: | 0 |
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