Distribution and hybridization of two sedentary gobies (Pomatoschistus microps and Pomatoschistus marmoratus) in the lagoons of southern France

Patrick Berrebi,Marielle Trébuchon

doi:10.3989/scimar.05029.15a

Abstract

Pomatoschistus marmoratus and Pomatoschistus microps are small sedentary gobies inhabiting the lagoons of European Mediterranean and Atlantic coasts. Along the French Mediterranean coast their respective geographical distribution is not precisely known, in part because they are cryptic species. In this study, 512 gobies of both species were caught as 17 samples in 12 lagoons of the Gulf of Lion on the French Mediterranean coast. They were genotyped at six microsatellite loci and investigated statistically using multidimensional analyses, Bayesian assignment (Structure) and NewHybrids classification. This allowed the contrasted distribution of each species (P. microps in the east, P. marmoratus in the west) to be described, with several exceptions. Neither geographic structure nor isolation by distance was detected among differentiated populations of each species. The suggested mechanism is a deep sedentary behaviour associated with foundations following extinctions. The two species are sympatric or even in syntopy in five or six sampled lagoons producing rare fertile hybrids.

Highlights

Gobies are teleost fish of the order Perciforms and the family Gobiidae (Miller 1986)
The Wahlund effect is probably the first cause in lagoons where intruders and hybrids have been found, but this disequilibrium has been detected in lagoons inhabited by one species only (Canet and Impériaux lagoons for P. microps; Marseillan 2, Mèze and ULM stations in Thau lagoon for P. marmoratus)
These significant deviations from Hardy-Weinberg equilibrium (HWE) due to heterozygote deficit were documented by González-Wangüemert and Vergara-Chen (2014) in all five populations and eight microsatellites in P. marmoratus in Mar Menor coastal lagoon in SE Spain

Summary

Introduction

Gobies are teleost fish of the order Perciforms and the family Gobiidae (Miller 1986). 2000 species of this family have been identified worldwide 1984, Nelson 2006) in all aquatic environments: continental, brackish and marine. In the Mediterranean, Miller (1986) considered 44 species described in marine and lagoon environments. This number climbed to 60 species in 25 genera (Quignard and Tomasini 2000). Trébuchon and to 62, 26 of them endemic to the Mediterranean (Ahnelt and Dorda 2004, Engin and Seyhand 2017)

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Conclusion