Event Abstract

Population structure and juvenile habitat use of dusky grouper (Epinephelus marginatus) in southern Brazil

  • 1 Federal University of Rio Grande, Institute of Oceanography, Brazil
  • 2 MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Portugal
  • 3 Southern Seas Ecology Laboratories, School of Biological Sciences, Darling Building, The University of Adelaide, Australia
  • 4 Universidade Federal Rural do Semi-Árido, Departamento de Ciências Animais, Brazil

A better understanding of population dynamics including the identification of reproductive areas and their contribution to the maintenance of fish stocks is essential for population conservation. Dusky grouper, Epinephelus marginatus, is a broadly distributed fish species, usually found in marine rocky bottoms. It is currently listed as “endangered” by the IUCN Red List. The available information on its population in southern Brazil suggests that the neritic habitat of Carpinteiro Bank - CB is the main growth and spawning ground in the region. We investigated if the dusky groupers caught in the rocky-jetties of Rio Grande city (a littoral artificial habitat with no spawning activity) originated from the CB. We sampled 28 individuals from the littoral rocky-jetties aged between 2 and 12 years, and 44 individuals from the neritic CB aged between 2 and 40 years. Individuals from both areas had their otolith sections analyzed with LA-ICPMS (core-to-edge profiles) for 86Sr:43Ca, 138Ba:43Ca ratios. The otolith core (natal origin) and edge (time shortly before capture) from individuals of the same age class showed no difference between the two sites. Individual profiles of 138Ba:43Ca ratios of fish from the littoral zone indicated, for the first time, that some juveniles of dusky grouper enter the Patos lagoon and remain within the estuarine environment between the first and second years of life. This interpretation of otolith chemical data is supported by the marked differences in salinity between the littoral and estuarine sites in these studies areas, and by the marked differences in otolith 138Ba:43Ca of other fish species analyzed along the salinity gradient in the Patos Lagoon estuary. The identification of differential juvenile habitat use patterns is crucial for the establishment and implementation of management and conservation strategies to safeguard this endangered species.

Acknowledgements

This study received financial support from the CAPES-Brasil (PVE NºA101/2013) and Fundação O Boticário de Proteção a Natureza (0962_20122). MVC and AMG acknowledge fellowship support from CNPq (140570/2013-6 and 305888/2012-9, respectively). This study also received support by the Fundação para a Ciência e a Tecnologia (FCT) (UID/MAR/04292/2013 and PTDC/MAR/117084/2010). SET and PRS were funded with FCT postdoctoral grants (SFRH/BPD/84278/2012 and SFRH/BPD/95784/2013, respectively).

Keywords: fish conservation, Life history plasticity, Movement, Natural tags, Patos Lagoon, Endangered Species

Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015.

Presentation Type: Poster Presentation

Topic: Otoliths as a tool to study fish life cycles

Citation: Condini MV, Tanner SE, Reis-Santos P, Albuquerque CQ, Vieira JP, Cabral H and Garcia AM (2015). Population structure and juvenile habitat use of dusky grouper (Epinephelus marginatus) in southern Brazil. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00108

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Received: 19 Nov 2015; Published Online: 21 Nov 2015.

* Correspondence: Mr. Mario V Condini, Federal University of Rio Grande, Institute of Oceanography, Rio Grande, Rio Grande do Sul, 96203-900, Brazil, mvcondini@gmail.com