Are landmarks analysis adequate to identify fish assemblages in a subtropical ecosystem? Study of case for the Araçá Bay (São Sebastião, Brazil)

Author(s)

Carolina Correia Siliprandi

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC)
• Defense date: 2018-08-08

Examining board members

Carmen Lucia Del Bianco Rossi Wongtschowski; Cristiano Queiroz de Albuquerque; June Ferraz Dias; Tito Monteiro da Cruz Lotufo; Alejandra Vanina Volpedo

• Advisor: Carmen Lucia Del Bianco Rossi Wongtschowski

Abstract

This thesis is part of the project \"Biodiversity and functioning of a subtropical coastal ecosystem: a contribution to integrated management\" funded by FAPESP - São Paulo Research Foundation - Process 2011/50317-5. Known as Biota Araçá, this project was performed in order to evaluate the diversity and the functionality of a subtropical tidal flat located at the northern coast of São Paulo State, a high diversity area. Our study, based on landmark analysis of fish body shape and otoliths shape, was conducted at the University of São Paulo in collaboration with researchers from the Institut de Ciències del Mar (Consejo Superior de Investigaciones Cientificas, Barcelona, Spain). The thesis was organized in five chapters. In the first one, we present a historical review about the use of morphology as a tool for the Science. Initially this theme was to supply my curiosity about \"how the shape of organisms contributed to the development of biodiversity studies\". The second chapter shows the dependence of the fish assemblages\' morphological structure according to the samplers utilized. For that, nine fishing gears were used to sample the Araçá fish assemblages and we determined which samplers are more useful to represent the total fish morphological variability of the area. Given the heterogeneity and complexity of habitats of Araçá Bay, we supposed that some habitats have major influence in the morphological diversity. Therefore, the aim of the third chapter was to determine how fish diversity techniques reveal the ichthyofauna of the three main habitats of Araçá Bay: intertidal, inner/outer sublittoral, marginal shallow sublittoral (elected as results of the previous chapter). Here we emphasize the importance of abundance data and morpho-functional approaches to understand fish habitat complexities, and consequently, the ecosystem functioning. Thus, we present the more sensible habitats in case of the Araçá\'s environmental degradation. During the development of our study, one question emerged: \"are sagittae landmarks able to describe the fish assemblage biodiversity as well as are fish body shapes?\" To answer this question, in the fourth chapter, the morphological correspondence between fish body shapes and otolith sagittae shapes were assessed. We investigated 43 species using different shape descriptors, attempting to habit, diet, swimming type, and hearing capabilities. Other specific questions were answered: 1- which method: shape indices, wavelets or landmarks, better discriminate species classification and, 2- which one shows the ecological significance of otoliths? In the last chapter, considerations are presented taking in account our initial question \"Are landmarks analysis adequate to identify fish assemblages in a subtropical ecosystem?\" The conclusion is that the method is a useful tool to describe fish body and otolith shapes as well as to define fish assemblages in highly diverse ecosystems. (AU)

• FAPESP's process: 14/20323-1 - Homologous points are suitable to identify fish assemblages in subtropical ecosystems? A case study for Araçá Bay
• Grantee: Carolina Correia Siliprandi
• Support Opportunities: Scholarships in Brazil - Doctorate