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Morphometric variations in white seabream Diplodus sargus (Linneus, 1758) populations along the Tunisian coast

Kaouèche M., Bahri-Sfar L., Hammami I., Hassine O. K. B.

Oceanologia

2017

No. 59 (2)

129--138

Morphometric characters of the white seabream Diplodus sargus (Linnaeus 1758) were compared among samples collected from six marine and lagoon sites along the Tunisian coast to elucidate the impact of the geographical barrier of the Siculo-Tunisian Strait and/or the lagoon environment in the morphological variation among the Tunisian white seabream population. Two morphometric descriptors (twenty-five Truss elements and six traditional measurements) were used to study the pattern of this morphological variation. Univariate analysis of variance revealed significant differences (P < 0.001) for both traditional and Truss variables. Multivariate analysis using the two morphometric descriptors detected a clear variation in the body shape between D. sargus populations along the Tunisian coast. All these analyses showed the distinctness of the sample from El Biban lagoon compared to the remaining ones. This discrimination was due to the head and the peduncle of the studied fish. Varying degrees of differences were also observed between northern and southern samples, and between the lagoon and the marine samples. The morphological variations of the head explain also the discrimination between the different lagoons samples. Observed morphological heterogeneity seems to be related to the impact of ecological factors.

Detection of two major cytochrome b lineages in pike-perch, Sander lucioperca, and first data on their distribution in European populations

Kohlmann K., Louati M., Kersten P., Bahri-Sfar L., Poulet N., Ben Hassine O. K.

Environmental Biotechnology

2013

Vol. 9, No. 1

1--5

Despite of the growing interest in pike-perch for aquaculture and its economic importance in fisheries, knowledge on the population structure and phylogeography of the species is still limited. We report the discovery of two major cytochrome b lineages and describe a simple method for their detection based on PCR amplification followed by restriction digestion with Alw26I. Screening of 708 individuals showed that haplotype A was fixed or dominating in Central and East European countries, whereas haplotype B was mainly found in several French populations and Tunisian pike-perch introduced from Europe. Sequencing the complete cytochrome b cds of 17 representative individuals revealed that haplotypes A and B differed by five substitutions but also showed further differentiation of both haplotypes due to an additional substitution in a single haplotype A and B individual from France, respectively. Five partial pike-perch cytochrome b cds available from NCBI GenBank could also clearly be assigned to one or the other of the two major lineages. Therefore, this new mtDNA marker might be considered as suitable not only for studies on population structure and phylogeography of pikeperch but also to trace its introduction history and to assess the genetic composition of aquaculture brood stocks.