Trophic ecology of young of the year Alboran Sea bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda) by stable isotope analyses

Abstract

Event Abstract Back to Event Trophic ecology of young of the year Alboran Sea bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda) by stable isotope analyses Ignacio Baro1, Amaya Uriarte2, Salvador García-Barcelona3, Maria Jose Gomez-Vives3, Samar Saber1, Jose M. Quintanilla2, Raul Laiz-Carrion2*, David Macias3 and Alberto García García2 1 Universidad de Málaga, Departamento de Biología Animal, Spain 2 Instituto Español de Oceanografía. C.O. Málaga, Spain 3 Instituto Español de Oceanografía. C.O. Málaga, Spain Bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda) spawn during summer in the oligotrophic waters of the Balearic Sea (NW Mediterranean). As they grow from larvae to juveniles, they migrate southwards reaching the more productive waters of the Alborán Sea. During August 2015, young-of-the-year (YOY) of both species was caught as forming part of the bycatch of the sardine purse seine fishery. The size range of YOY was from 16-21cm for bluefin and 19-25cm for bonito. Nowadays, knowledge on the trophic ecology of these YOY specimens is very scarce. This study has the objective of analyzing the trophic ecology and estimating trophic position (TP) of both species by bulk stable isotope analysis (SIA) and by compound specific isotope analysis of amino acids (AA-CSIA). Bluefin specimens were caught in two environmentally differentiated sites from the hydro-biological viewpoint, the Bay of Málaga and Gulf of Vera (Almería). Atlantic bonito specimens used for this study come from the Bay of Málaga only. SIA showed differences between bluefin and Atlantic bonito, the latter showing significantly higher values of the nitrogen stable isotope. No differences between species were observed with respect to the stable isotope of carbon. Although no baseline levels were available to determine trophic position by SIA, it can be assumed that both species have similar baselines. Therefore, we can infer that bonito show a greater trophic specialization in comparison to bluefin. On the other hand, AA-CSIA determines TP without needing trophic baselines. The models proposed by Chikaraishi et al. (2009) for aquatic food-webs and modified by Bradley et al. (2015) for marine teleosts, using glutamic acid as trophic AA and phenylalanine as source AA were used for this study. The estimated TP showed similar results to SIA where bonito YOY recorded higher TP in comparison to bluefin YOY. Nonetheless, the difference was not significant probably due to small sample size for AA-CSIA. SIA showed differences by site sampled in bluefin YOY where Malaga Bay specimens showed significantly higher □□15N values. No differences between sites were observed with respect to □□13C values. TP by site did not show significant differences. However, TP showed a positive linear relationship with fork length (FL) suggesting a greater trophic specialization with growth. SIA and CSIA are tools widely used for early life food web dynamics and this study shows the complementary uses of both approaches. Significant differences of stable isotopes values for some trophic amino acids possibly indicate dietary differences of prey consumption. Further complementary studies contemplating stomach content analysis will contribute to a better understanding of the trophic ecology at early life stages in tunas like species. Figure 1 Figure 2 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). References Chikaraishi Y., Ogawa N.O., Kashiyama Y., Takano Y., Suga H., Tomitani A., Miyashita H., Kitazato H. and Ohkouchi, N. 2009. Determination of aquatic food-web structure based on compound-specific nitrogen isotopic composition of amino acids. Limnology Oceanography: Methods 7: 740–750. Bradley C.J., Wallsgrove N.J., Choy C.A. Drazen J.C., Hetherington E.D., Hoen D.K. and Popp B.N. 2015. Trophic position estimates of marine teleosts using amino acid compound specific isotopic analysis Limnol. Oceanogr.: Methods 13(9): 473-493. Keywords: Bluefin tuna, Atlantic bonito, young of the year, trophic ecology, stable isotope Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 4. FISHERIES, AQUACULTURE AND BIOTECHNOLOGY Citation: Baro I, Uriarte A, García-Barcelona S, Gomez-Vives M, Saber S, Quintanilla JM, Laiz-Carrion R, Macias D and García García A (2016). Trophic ecology of young of the year Alboran Sea bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda) by stable isotope analyses. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00191 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: PhD. Raul Laiz-Carrion, Instituto Español de Oceanografía. C.O. Málaga, Fuengirola, Málaga, 29640, Spain, raul.laiz@ieo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ignacio Baro Amaya Uriarte Salvador García-Barcelona Maria Jose Gomez-Vives Samar Saber Jose M Quintanilla Raul Laiz-Carrion David Macias Alberto García García Google Ignacio Baro Amaya Uriarte Salvador García-Barcelona Maria Jose Gomez-Vives Samar Saber Jose M Quintanilla Raul Laiz-Carrion David Macias Alberto García García Google Scholar Ignacio Baro Amaya Uriarte Salvador García-Barcelona Maria Jose Gomez-Vives Samar Saber Jose M Quintanilla Raul Laiz-Carrion David Macias Alberto García García PubMed Ignacio Baro Amaya Uriarte Salvador García-Barcelona Maria Jose Gomez-Vives Samar Saber Jose M Quintanilla Raul Laiz-Carrion David Macias Alberto García García Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.