Low levels of genetic diversity depicted from mitochondrial DNA sequences in a heavily exploited marine fish (Cynoscion acoupa, Sciaenidae) from the Northern coast of Brazil

Horacio Schneider,Rosa Rodrigues,Ulrich Sain-Paul,Simôni Santos,Iracilda Sampaio,Marcelo Vallinoto

doi:10.1590/s1415-47572008000300015

Horacio Schneider, Rosa Rodrigues + Show 4 more

Open Access

https://doi.org/10.1590/s1415-47572008000300015

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Abstract

The acoupa weakfish (Cynoscion acoupa - Sciaenidae) is a marine species of croaker with estuarine-dependent behavior, found in the western Atlantic from Panama to Argentina. It is one of the most exploited food fish on the northern coast of Brazil. In this study, DNA sequences were determined from the entire control region (D-loop) of the mitochondrial genome of 297 individuals collected during seven different months between December 2003 and August 2005 on the northern coast of Brazil (Amapa and Para). Genetic variability expressed by haplotype (h = 0,892) and nucleotide (p = 0,003) diversities were low compared to other heavily exploited marine fish species from the western Atlantic and eastern Asia. AMOVA depicted a lack of genetic structuring among the samples from different years, indicating the presence of a single stock of C. acoupa within the sample area. The possible reasons for the low levels of genetic diversity are discussed. These results demonstrate a need for the monitoring of C. acoupa harvesting and the preservation of the estuaries within its geographic range, considering that this large fish depends on estuarine ecosystems during part of its life cycle.

Highlights

The Sciaenidae family encompasses 70 genera and 270 species of mainly marine and estuarine fish, distributed throughout the tropical areas of the Atlantic, Indian and Pacific oceans (Trewavas, 1977; Nelson, 1994)
We used DNA sequences of the mitochondrial D-loop region to characterize the genetic diversity of the C. acoupa stock from northern Brazil - the Amazon coast - using samples collected over a three year period (2003 to 2005)
Sequences of the same segment of the mitochondrial D-loop have been employed in a number of studies to investigate genetic structuring and demographic history in populations of overexploited fishes, in which the observed values of h and π were much higher than those recorded for C. acoupa in the present study

Summary

Introduction

The Sciaenidae family encompasses 70 genera and 270 species of mainly marine and estuarine fish, distributed throughout the tropical areas of the Atlantic, Indian and Pacific oceans (Trewavas, 1977; Nelson, 1994). Despite the commercial importance of C. acoupa, the population-level genetic variability of the species is unknown.

Results

Conclusion