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Fishing stocks and demographic history of Sardines

Background

Questions

Implications

Team

How do environmental variability and exploitation impact the demography of a sardine species?

Understanding the genetic diversity of species is crucial for conservation, especially with human activities impacting the still unknown marine biodiversity. To better manage and conserve exploited marine species, it is relevant to understand how many independent lineages exist, and what is their demographic history. With the Sardines project, we addressed these on a sardine species of the genus Harengula, which is yet undescribed but already overexploited, causing lack of clarity and conflicts in conservation measures.

By using both habitat modeling and genetic studies,we answer:

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1. How have temporal and spatial changes in habitat suitability constrained the distribution of Harengula sp.?
2. How did these changes affect the divergence and gene flow within Harengula sp.?
3. What is the magnitude and direction of gene flow between independent lineages?
4. What is the demographic history of each lineage of Harengula sp. after the population split?
5. Was the recent demographic history affected by human exploitation?

By an integrative approach using ecological niche modeling, genomic data, and demographic modeling, we provide data to support better management strategies focused on the sustainable fishing of this species.

Ricardo Pereira (SMNS), Jéssica Coelho (UFRN), Julia T. Verba (LMU), Sergio Lima (UFRN)

Fig. 1. Distribution of the scaled sardine Harengula sp. in the Southwest Atlantic. Study area for occurrence records (marked by asterisk), and for sampling sites also included in the genomic analyses (colored circles). Sampling localities: FNO Fernando de Noronha archipelago (oceanic island), CE Ceará, RN Rio Grande do Norte, PB Paraíba, PE Pernambuco, AL Alagoas, BA Bahia, ABR Abrolhos (continental island), ES Espírito Santo, RJ Rio de Janeiro, SP São Paulo, SC Santa Catarina.

Fig. 1. Distribution of the scaled sardine Harengula sp. in the Southwest Atlantic. Study area for occurrence records (marked by asterisk), and for sampling sites also included in the genomic analyses (colored circles). Sampling localities: FNO Fernando de Noronha archipelago (oceanic island), CE Ceará, RN Rio Grande do Norte, PB Paraíba, PE Pernambuco, AL Alagoas, BA Bahia, ABR Abrolhos (continental island), ES Espírito Santo, RJ Rio de Janeiro, SP São Paulo, SC Santa Catarina.

Fig. 2. Genomic similarity between intraspecific lineages of the scaled sardine Harengula sp. Principal Component Analysis indicates a split between coastal sites and the island of Fernando de Noronha, suggesting that coast and island stocks should be managed independently. 

Fig. 2. Genomic similarity between intraspecific lineages of the scaled sardine Harengula sp. Principal Component Analysis indicates a split between coastal sites and the island of Fernando de Noronha, suggesting that coast and island stocks should be managed independently. 

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