Molecular Characterization of the Common Snook, Centropomus undecimalis (Bloch, 1792) in the Usumacinta Basin

Abstract

The common snook is one of the most abundant and economically important species in the Usumacinta basin in the Gulf of Mexico, which has led to overfishing, threatening their populations. The main goal of the present study was to assess the genetic diversity and structure of the common snook along the Usumacinta River in order to understand the population dynamics and conservation status of the species. We characterized two mitochondrial markers (mtCox1 and mtCytb) and 11 microsatellites in the Usumacinta basin, which was divided into three zones: rainforest, floodplain and river delta. The mitochondrial data showed very low diversity, showing some haplotypic diversity differences between the rainforest and delta zones. In contrast, we consistently recovered two genetic clusters in the Usumacinta River basin with the nuclear data in both the DAPC and STRUCTURE analyses. These results were consistent with the AMOVA analyses, which showed significant differences among the genetic clusters previously recovered by DAPC and STRUCTURE. In terms of diversity distribution, the floodplain zone corresponded to the most diverse zone according to the mitochondrial and nuclear data, suggesting that this is a transition zone in the basin. Our results support the relevance of the molecular characterization and monitoring of the fishery resources at the Usumacinta River to better understand their connectivity, which could help in their conservation and management.

Otolith microchemistry highlights the importance of extensive connectivity for conservation of an iconic migratory fish in a large tropical river basin

“…consistent with the high degree of connectivity described in recent population genetics workTerán-Martínez et al, 2021) Terán- Martínez et al (2021). found some genetic differences among fish collected in the rainforest vs. the delta zones of the Usumacinta, with the floodplain zone probably representing an area of mixture between these groups.…”

“…Others have proposed that common snook may use the floodplain habitats in the Usumacinta for reproduction (Terán‐Martínez et al, 2021), and individuals in spawning‐capable condition have been captured in riverine habitats (Hernández‐Vidal, Chiappa‐Carrara & Contreras‐Sánchez, 2014). However, riverine spawning has never been observed, and studies of the reproductive physiology of Usumacinta common snook suggest that spawning occurs in coastal habitats as in other regions (Perera‐García et al, 2011; Hernández‐Vidal, Chiappa‐Carrara & Contreras‐Sánchez, 2014; Hernández‐Vidal et al, 2021).…”

“…For example, Atlantic and Gulf of Mexico stocks within Florida have distinct growth, reproductive and migration characteristics (Tringali & Bert, 1996;Taylor, Wittington & Grier, 2000;Stevens et al, 2018), and populations in Texas (Huber et al, 2014) . The extent of inland habitat use and the dependence of common snook populations on river connectivity are critical data needs (Huber et al, 2014;Terán-Martínez et al, 2021).…”

“…For example, Atlantic and Gulf of Mexico stocks within Florida have distinct growth, reproductive and migration characteristics (Tringali & Bert, 1996; Taylor, Wittington & Grier, 2000; Stevens et al, 2018), and populations in Texas (Huber et al, 2014) and southern Mexico have been documented to use riverine habitats further upstream from the coast (in terms of total river kilometres) compared with Florida populations (Hernández‐Vidal, Chiappa‐Carrara & Contreras‐Sánchez, 2014). The extent of inland habitat use and the dependence of common snook populations on river connectivity are critical data needs (Huber et al, 2014; Terán‐Martínez et al, 2021).…”

“…Common snook are frequently captured more than 300 river kilometres (rkm) upstream from the Usumacinta delta, and some individuals reach advanced stages of gonadal maturity while still in river habitats (Hernández‐Vidal, Chiappa‐Carrara & Contreras‐Sánchez, 2014; Hernández‐Vidal et al, 2021). A recent analysis of common snook population genetics in the Usumacinta basin suggests that there is very little spatial structuring (few private alleles across the basin, low genetic differentiation as estimated with F ST values), indicating high connectivity in this system (Terán‐Martínez et al, 2021). This evidence indicates that river migration is important for common snook in the Usumacinta basin, and such movements are possible because this basin is one of the largest Neotropical rivers that remains largely undammed.…”