Influence of hydrodynamic connectivity on the genetic structure and gene flow of the common pandora Pagellus erythrinus

Abstract

Many marine organisms have complex genetic patterns that cannot be easily resolved by data analysis on spatial distribution of variability usually applied in population genetic studies. We propose an analytical framework to evaluate the role of dispersal during early life stages that considers the actual hydrodynamic connectivity in the Mediterranean Sea, as a factor shaping the population structure of demersal fishes. To this purpose, and to test different scenarios of gene flow, genotypes of individuals of Pagellus erythrinus sampled at 12 sites in the central Mediterranean Sea were analyzed at ten microsatellite loci. The results show the lack of genetic structure in western Mediterranean basin and a pattern of gene flow that deviates from an isolation by distance model. The observed gene flow estimates appear to be scale-dependent. At local scale, it is likely the result of multifactorial components whereas at a larger scale it is mainly driven by the sea currents, directly influencing dispersal of larvae between sites not reachable by adult movements. Our results stress the importance of a quantitative analysis of potential early life stage dispersal in any study focusing on the population structure of fishes with a long larval stage.

Matching an Old Marine Paradigm: Limitless Connectivity in a Deep-Water Fish over a Large Distance

“…Although a general agreement exists regarding the Strait of Gibraltar as the main spawning area for the Eastern Atlantic Ocean-Western Mediterranean region [14,33,78], scarce information is available about daily and seasonal displacements of adults, spawning strategies (especially depth range), and ELS dynamics (buoyancy, Pelagic Larval Duration, etc.). Nevertheless, the migration of spawners registered by otoliths' microchemistry [34], and the powerful tidal dynamics of the Strait of Gibraltar, strongly affect the dispersal patterns of the ELS and may justify the genetic homogeneity observed across the Alboran region.…”

“…Nevertheless, the migration of spawners registered by otoliths' microchemistry [34], and the powerful tidal dynamics of the Strait of Gibraltar, strongly affect the dispersal patterns of the ELS and may justify the genetic homogeneity observed across the Alboran region. The general dispersal pattern of ELS seems to interest the northern (Tarifa) and southern Strait (Tangier), and it is strongly modulated by distance, travelling speed, and scattering by the fortnightly tidal cycle (spring-neap tide alternation) and spawning depth [33,78,79]. Here, the Atlantic jet might be the main cause of a zonal (west-east) connectivity within the Alboran Sea, while the north-south and less stable dispersal might depend on the low-frequency variability of the flow [33].…”

“…From a biological perspective, the current knowledge of the connectivity and differentiation of Blackspot Seabream populations derives from different techniques and separate approaches that have been progressively, but not yet holistically, integrated to properly assess its population structure at very different spatial scales [14,30]. The little available information on the dispersal capability of Blackspot Seabream was inferred according to comparisons with species having similar bio-ecological features [31][32][33]. To this end, Nadal et al [30] studied and described how the Alboran Sea's oceanographic features could passively control the dispersal of the Early Life Stage (ELS) individuals and lead to a secure connection between the Strait of Gibraltar and the Alboran Sea itself [34].…”

Spatiotemporal analysis of the genetic and morphological variation of Iphigenia brasiliensis (Mollusca: Bivalvia) from the southwest tropical Atlantic

“…type of material that can be used, the record of phenotypes, and underestimation of the total genetic variation) and theoretical limitations (e.g. discussion about locus neutrality), mainly when the studies concern the influence of latitudinal, temporal, and environmental effects on genetic variation (Kuzishchin et al 2018, Montagna et al 2018, Bonner et al 2019, Lauterjung et al 2019, Rossi et al 2019. Allozymes have also been a good tool for investigating the relationships between genetic and morphological variation (Ryman et al 1984, Zink 1988, Cruz et al 2011, Vetrova et al 2016.…”

Genetic structure of the long-snouted seahorse,Hippocampus guttulatus, in the Central–Western Mediterranean Sea

“…In the marine environment, genetic homogeneity is expected across vast areas due to the lack of obvious physical barriers to dispersal and the existence of planktonic larvae in many species (Cowen et al, 2007). Although dispersal capacity is considered one of the principal factors in shaping population genetic structure, it may not always be the only driver of diversification (Rossi et al, 2019). Indeed, population structure is often the result of a complex interaction between environmental, historical and individual or species-specific characteristics, including local adaptation (Gentili et al, 2018), historical vicariance (Nascimento et al, 2018), past bottleneck events (Shama et al, 2011), oceanic currents (Rossi et al, 2019), habitat discontinuities (Barber et al, 2002), isolation by distance (Mims et al, 2016), limited dispersal abilities (Ferreira et al, 2015), behaviour and life history strategies (Nathan et al, 2008).…”