Larval population structure of Engraulis encrasicolus in the Strait of Sicily as revealed by morphometric and genetic analysis

Abstract

In order to investigate the larval population structure, specimens of Engraulis encrasicolus larvae from five different locations in the Strait of Sicily were analyzed by means of otolith readings, morphometric and genetic techniques. The distribution of age in day, identified by means of the otolith readings and associated with the oceanographic parameters, was useful to identify possible spawning areas and transport dynamics. The presence of more than one spawning area suggested the possibility that two or more sub‐populations may co‐exist in the study area. The morphometric characteristics were more adequate than genetic parameters to discriminate the different larval groups. The most relevant variables for the separation were the mouth length (ML) and the body diameter (BD). The population structure by means of genetic data reported the presence of two phylogroups co‐occurring among samples in each sampling locations specimens. The pattern of genetic divergence among anchovy larvae in the Strait of Sicily was congruent with previous studies conducted on adult populations present in other Mediterranean areas with different molecular markers. The habitat‐specific nature of the morphological variation and the lack of corresponding genetic variation among larvae from the different locations suggested that the observed differences in morphology could be linked to environmental parameters. The body form differences among different larvae samples could reflect the nutritional status of larvae. In fact, these differences were found among anchovy larvae collected in areas with different oxygen and fluorescence, which is an index of primary productivity and is linked to the availability of food for anchovy larvae.

Seascape connectivity of European anchovy in the Central Mediterranean Sea revealed by weighted Lagrangian backtracking and bio-energetic modelling

“…In this framework, our findings suggest that mortality of anchovy larvae caused by starvation is expected to be low along their trajectories and hence indicates significant connectivity among GSAs. These results are consistent with Cuttitta et al 41 , which characterized the genetic structure of the European anchovy populations in the Strait of Sicily. These authors found the existence of two different phylogroups probably differentiated during the Pliocene–Pleistocene period and currently not geographically separated.…”

Different key roles of mesoscale oceanographic structures and ocean bathymetry in shaping larval fish distribution pattern: A case study in Sicilian waters in summer 2009

“…It was characterized by a very complex sea circulation that can have strongly influenced the spawning strategy and the recruitment success of many fish species (Cuttitta et al, 2003Fortibuoni et al, 2010;Garofalo et al, 2010). In particular, many studies Cuttitta et al, 2015;Falcini et al, 2015;García Lafuente et al, 2002) have focused on the influence of oceanographic factors on the ecology and reproductive biology of the European anchovy (Engraulis encrasicolus), which is the target species of fisheries along the southern coast of Sicily, representing one of major fish resource in terms of economic importance (Patti et al, 2005(Patti et al, , 2012. In this study, the influence of the circulation pattern in the Strait of Sicily on the distribution of fish larvae was very clear and it can be considered the main factor governing the larval fish retention and shaping the observed assemblages.…”

A COI Nonsynonymous Mutation as Diagnostic Tool for Intraspecific Discrimination in the European Anchovy Engraulis encrasicolus (Linnaeus)

“…All these environmental features are known to modify the temperature regime of the surface waters in the Sicilian anchovy habitat [ 21 , 22 ]. Although the Sicilian Channel can be considered a key zone in the Mediterranean basin for the European anchovy population structure, few genetic studies [ 23 ] have been carried out in this area that was identified by Garcia Lafuente et al [ 24 ] as one of the main spawning area of E . encrasicolus .…”