The Tonkin weakfish, Cynoscion similis (Sciaenidae, Perciformes), an endemic species of the Amazonas-Orinoco Plume

Rodrigo Antunes Caires,Leonardo Machado,Claudio Oliveira,Cintia Oliveira,Wagner C R Dos Santos,Najila N C D Cerqueira,Matheus Marcos Rotundo,Alexandre P Marceniuk

doi:10.1590/1809-4392201803481

Abstract

ABSTRACT Despite its importance in biogeographical, ecological, and commercial terms, the fish fauna of the northern Brazilian coast is still poorly known, representing the least sampled portion of the Brazilian Exclusive Economic Zone. We collected Tonkin weakfish, Cynoscion similis specimens during extensive surveys of the northern Brazilian coast and concluded that C. similis is common in this region. While the species had not previously been reported for the northern Brazilian state of Pará, it may have been recorded in studies of industrial fisheries, being identified only as Cynoscion sp. or by the common name pescada negra. This reinforces the need for the reliable taxonomical identification of species, to guarantee the collection of accurate data on ecology and fisheries, and ultimately, support the development of effective conservation strategies. Here we provide additional morphological and molecular data to distinguish Cynoscion similis from the closely related Cynoscion jamaicensis, and other congeners.

Highlights

The Tonkin weakfish or pescada negra, Cynoscion similis Randall & Cervigón, 1968, was described from specimens collected on the coast of Venezuela, Suriname, and French Guiana
The present study reports the occurrence of Cynoscion similis on the northern coast of Brazil, and provides a new morphological diagnosis of the species, together with an analysis of its DNA barcode
Cynoscion similis showed to be common on the Brazilian continental shelf, targeted by industrial trawling fisheries in Pará, while C. jamaicensis is more common in the coastal zone, at depths of less than 40 m, where it is typically exploited by artisanal gillnet fisheries

Summary

Introduction

The Tonkin weakfish or pescada negra, Cynoscion similis Randall & Cervigón, 1968, was described from specimens collected on the coast of Venezuela, Suriname, and French Guiana. In a review of the classification of the sciaenids of the western North Atlantic, Chao (1978) noted that Cynoscion similis is found from “Venezuela to Brazil”, its occurrence on the Brazilian coast is known only from records from the state of Amapá (http://www.fishnet2.net). This position was perpetuated in subsequent publications, as in the paper of Uyeno et al (1983) on the fish species trawled off Suriname and French Guyana, and in the list of Brazilian marine fishes (Casatti and Menezes 2003). LucenaFrédou, pers. comm. 2009)” (Chao and Aguillera 2015)

Methods

Discussion

Conclusion