Photo: Marilene Viero / Funbio

Understanding the habitat-use patterns of fish populations is key to assessing their resilience to habitat destruction and fishing, and is essential to the proper application of conservation and sustainable-use measures.

Many coastal fish species move between the shallow waters of bays, estuaries, coastal lagoons and the continental shelf over the course of a lifetime. The microchemical analysis of otoliths— calcium carbonate particles found in the inner ear—enables scientists to study these movements. Environmental Trace elements left upon these otoliths function as “chemical markers” that make it possible to track fish migrations.

The main aim of the initiative “Microchemical Analysis of Otoliths as a Tool for Identifying Fish Stocks, Migration Patterns and Habitat Connectivity along the Rio de Janeiro Coast”, run by the Federal Rural University of Rio de Janeiro’s Foundation for the Support of Scientific and Technological Research (Fapur), is to use microchemical analyses to identify movement and migration patterns among the study populations and to ascertain the degree of connectivity between these populations along the Rio de Janeiro coast. The project will study the distribution of juvenile and adult shoals of whitemouth croaker (Micropogonias furnieri), striped mullet (Mugil liza), smooth weakfish (Cynoscion leiarchus) and common snook (Centropomus undecimalis), all important catch species in Rio.