ECOLOGICAL FUNCTION OF SHARKS IN DIFFERENT ENVIRONMENTS ACCORDING TO TROPHIC MODELS AND TOPOLOGICAL ANALYSIS.

• Grant number: 13/25930-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2014
• End date: April 30, 2016
• Field of knowledge: Biological Sciences - Zoology - Applied Zoology
• Principal Investigator: Alberto Ferreira de Amorim
• Grantee: Hugo Bornatowski
• Host Institution: Instituto de Pesca. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Large sharks as apex predators are important links between trophic levels, determining the size of levels through direct (predation) and indirect effects (e.g. apparent competition, exclusion competition, risk effects) of predator-prey relationships. In this sense, the decline of large predators populations will lead to increases in populations of intermediate components, consequently leading to the reduction in populations of intermediates' prey. Therefore, understanding the trophic interactions between large sharks, identifying keystone species and detecting which exert top-down and bottom-up effects is fundamental to evaluate the stability and dynamics of ecosystems, especially those who suffer intense fishing pressure. Furthermore, studies of ecological function of sharks together with long-term fishing data can provide information on the fishing impacts on ecosystems. Thus, this project aims to evaluate the importance of sharks in two ecosystems (oceanic versus coastal), located in southeastern and southern Brazil, using two methodologies: 1) Mass-balanced models (with Ecopath software) and 2) topological analyses. Therefore, the questions to be answered are: I) Large sharks are keystone species in the studied ecosystems? II) Through simulations of fishing data, the reductions of large sharks lead to destabilization of the trophic structure in the two ecosystems? III) Both methodologies are compatible for trophic analysis or shows divergent results?

Scientific publications

(6)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

BORNATOWSKI, HUGO; BARRETO, RODRIGO; NAVIA, ANDRES F.; DE AMORIM, ALBERTO FERREIRA. Topological redundancy and ``small-world' patterns in a food web in a subtropical ecosystem of Brazil. MARINE ECOLOGY-AN EVOLUTIONARY PERSPECTIVE, v. 38, n. 2, APR 2017. (13/25930-0)

BORNATOWSKI, HUGO; BARRETO, RODRIGO; NAVIA, ANDRES F.; DE AMORIM, ALBERTO FERREIRA. Topological redundancy and "small-world' patterns in a food web in a subtropical ecosystem of Brazil. MARINE ECOLOGY-AN EVOLUTIONARY PERSPECTIVE, v. 38, n. 2, p. 7-pg., 2017-04-01. (13/25930-0)

VINICIUS J. GIGLIO; HUGO BORNATOWSKI. Fishers' ecological knowledge of smalleye hammerhead, Sphyrna tudes , in a tropical estuary. Neotropical Ichthyology, v. 14, n. 2, 2016-06-20. (13/25930-0)

BORNATOWSKI, HUGO; ANGELINI, RONALDO; COLL, MARTA; BARRETO, RODRIGO R. P.; AMORIM, ALBERTO F.. Ecological role and historical trends of large pelagic predators in a subtropical marine ecosystem of the South Atlantic. Reviews in Fish Biology and Fisheries, v. 28, n. 1, p. 241-259, MAR 2018. (13/25930-0)

WOSNICK, NATASCHA; BORNATOWSKI, HUGO; FERRAZ, CAROLINA; AFONSO, ANDRE; RANGEL, BIANCA SOUSA; VIEIRA HAZIN, FABIO HISSA; FREIRE, CAROLINA ARRUDA. Talking to the dead: using Post-mortem data in the assessment of stress in tiger sharks (Galeocerdo cuvier) (P,ron and Lesueur, 1822). FISH PHYSIOLOGY AND BIOCHEMISTRY, v. 43, n. 1, p. 165-178, FEB 2017. (13/25930-0)

GIGLIO, VINICIUS J.; BORNATOWSKI, HUGO. Fishers' ecological knowledge of smalleye hammerhead, Sphyrna tudes, in a tropical estuary. Neotropical Ichthyology, v. 14, n. 2, 2016. (13/25930-0)