Otoliths as a tool to study reef fish population structure from coastal islands of South Brazil

ABSTRACT

To promote marine conservation and sustainable resources use it is highly important to understand reef fish population structure and dynamics. The sergeant major, Abudefduf saxatilis, is a common and abundant fish usually found in the Brazilian coasts, being considered a keystone-species for structuring benthic communities on reef habitats in the Atlantic Ocean. This study examined the morphology (shape indices and elliptic Fourier descriptors) and chemistry (Element:Ca) of A. saxatilis sagittal otoliths, collected in seven locations along the coast of South Brazil. Otolith morphology and chemistry were compared at short (range 0.5–2 km) and large (range 70–140 km) spatial scales using univariate and multivariate statistical approaches. Reclassification accuracy rates obtained from linear discrimination function analyses using both morphology and chemistry of otoliths were 61% and 82% for short and large spatial scales, respectively. No clear separation for individuals collected in islands within the Tamboretes Archipelago were observed suggesting that water masses are relatively homogeneous and/or that individuals could be highly mixed over short spatial scales. However, the higher reclassification success of the individuals belonging to Bom Abrigo, Galheta and Paz islands, indicates a limited movement of adults between habitats, a larval retention mechanism or a self-recruitment process occurring at large spatial scales.

SUBJECT EDITOR:

• Audrey Geffen

KEYWORDS:

• Abudefduf saxatilis
• sagittae
• shape and chemical analyses
• life history

Acknowledgements

The authors are grateful to the Center of Studies of the Sea for sampling support.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Johnatas Adelir-Alves http://orcid.org/0000-0002-8882-4009

Alberto T. Correia http://orcid.org/0000-0002-2831-025X

Additional information

Funding

J.A.A. and M.S. acknowledge individual scholarship grants from Brazilian Agency for Support and Evaluation of Graduate Education (CAPES). This research was supported by the National Council of Technological and Scientific Development (CNPq) (473181/2012-6 and 401190/2014-5). This study was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by the Portuguese Foundation for Science and Technology (FCT) and European Regional Development Fund (ERDF), in the framework of the program PT2020. F.A.D. received a postdoctoral fellowship (CAPES–1669551) and A.T.C. benefited from a Special Visiting Research Fellowship (CNPq/PVE–314444/2014-9).