Event Abstract

Trophic position of Mediterranean bluefin tuna larvae estimated by different stable isotope analysis

  • 1 Instituto Español de Oceanografía, Málaga/PhD student, Ictioplancton, Spain
  • 2 Woods Hole Oceanographic Institution, Biology Department, United States
  • 3 Instituto español de Oceanografía, Spain

Bluefin tuna (Thunnus thynnus) is a migratory species that spawns in highly oligotrophic open waters off the Balearic archipielago during the months of June/July. The scarcity of feeding resources is a most critical issue for larval surviving, mainly in these oligotrophic scenarios. Stable isotope analysis aids revealing what fractions of the early life food chain are being consumed by the larvae of this top predator. Bluefin tuna larvae were collected within two ichthyoplankton surveys carried out during June 2013 and 2014 in the Balearic Sea. For undertaking a trophic ecology study, two independent stable isotope analysis methods were realized on larvae from these surveys ranging from 3 to 10mm. Bulk stable isotope analysis (SIA) was carried out on individual larvae and on the microzooplankton fraction (50-200µm) for each station, whereas bluefin tuna larvae were pooled in size classes (range 1mm) for compound-specific amino acids isotope analysis (AA-CSIA). Both methods revealed a common pattern, showing significant differences between pre-flexion and post-flexion larvae. Higher isotopic signatures occurred in the early stages due to isotopic maternal transmission, and consequently, the use of pre-flexion larvae is not recommended for estimating trophic position. No significant differences were observed between estimates of trophic position using both analytical methods. Both analytical tools of stable isotope analysis (SIA and AA-CSIA) demonstrate its potential for understanding the dynamics of the food webs in which early life stages of fishes dwell.

Figure 1

Acknowledgements

This study was partly funded by ATAME project (CTM2011-29525-C04-02). A.Uriarte was recipient of a predoctoral fellowship FPI-IEO 2011/03 (Spanish Institute of Oceanography).

This work was supported by grant ECOLATUN CTM2015-68473-R (MINECO/FEDER). Amaya Uriarte was recipient of a predoctoral fellowship FPI-IEO 2011/03 (Spanish Institute of Oceanography).

Keywords: Atlantic bluefin tuna, larval ecology, stable isotope, Amino Acids, Trophic position

Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016.

Presentation Type: Oral Presentation

Topic: 4. FISHERIES, AQUACULTURE AND BIOTECHNOLOGY

Citation: Uriarte A, Laiz Carrión R, Llopiz J, Quintanilla Hervas JM, Alemay F and Garcia Garcia A (2016). Trophic position of Mediterranean bluefin tuna larvae estimated by different stable isotope analysis. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00083

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Received: 29 Apr 2016; Published Online: 02 Sep 2016.

* Correspondence:
PhD. Amaya Uriarte, Instituto Español de Oceanografía, Málaga/PhD student, Ictioplancton, Fuengirola-Málaga, Málaga, 29640, Spain, amaya.uriarte@ma.ieo.es
PhD. Raúl Laiz Carrión, Instituto Español de Oceanografía, Málaga/PhD student, Ictioplancton, Fuengirola-Málaga, Málaga, 29640, Spain, raul.laiz@ieo.csic.es