Da ginga à sardinha: etnoictiologia e sistemática molecular de pequenos peixes de valor cultural da costa brasileira

Abstract

The assessment of fishery stocks for sustainable management and conservation measures are made using fishery statistics, which requires reliable data and is, in most cases, based on popular names. However, basic data such as taxonomy, popular names, geographical distribution, and delimitation of stocks, for example, often are not available, which compromise fishery management. Thus, this project combines ethnoichthyology and phylogeographic analyses of the clupeids Opisthonema oglinum and Harengula spp. to identify their popular names and investigate their phylogeographic patterns, and then delimit fish stocks on the Brazilian coast. In the first chapter, I describe the perception of fishers and local consumers of what is “ginga”, which are small coastal fish and are part of the typical dish “ginga com tapioca”, an intangible cultural heritage of the Rio Grande do Norte state. Through interviews and specimens at fish markets in six locations in three states of Northeastern Brazil, we found that “ginga” consists of juvenile individuals of some sardine and anchovy species, and that the only difference between “ginga” and sardine is the size, “ginga” representing the smaller fishes and sardines the larger, sometimes of the same species. The popular name is basically restricted to the metropolitan region of Natal city. In addition, the “ginga” can be considered a "culturally important species" and, therefore, should among the target species for conservation and local management. In the second chapter, we compare the phylogeographic patterns of the two most representative groups of “ginga”, O. oglinum and Harengula spp., along their supposed Western Atlantic distributions using the mitochondrial marker CO1. Additionally, we investigate how many stocks of these taxa are on the Brazilian coast and in the oceanic archipelago of Fernando de Noronha. In this archipelago, sardines are used as bait for artisanal fishing, and this have been generating a conflict between fishers and environmental agencies. The lack of basic information, such as the taxonomic identity of species, is essential for sustainable management. Our results indicate O. oglinum as a single lineage in the entire Western Atlantic, but shows population structure between Brazil, USA+Mexico, and Bermuda, and Harengula as two species, Harengula clupeola and H. jaguana in North America and the Caribbean and one distinct lineage in Brazil, which might be a new species. When evaluating these taxa in a temporal context, revealed that the separation between the Harengula species in the northern hemisphere and Brazil coincides with the increased discharge of the Amazon and Orinoco rivers. With these results it is possible to observe that, despite the similar biology, O. oglinum and Harengula spp. do not have the same phylogeographic pattern and must be handled differently.