Variations in nutritional quality and fatty acids composition of sardine (Sardina pilchardus) during canning process in grape seed and olive oils.

Fish canning industries generally use different oils to ensure the juicing stage of canned sardines. In this context, we tested the use of grape seed oil (GSO) which could provide several health benefits to consumers. This study compared its effects on the quality of canned sardine to that of olive oil (OO). Total polyphenols, flavonoids and non flavonoids of the tested GSO were significantly higher than those of the OO. Also, The GSO was rich in polyunsaturated fatty acid (PUFA), namely linoleic acid (65.36% of total fatty acids). The use of GSO in the sardine sardines canning process increased significantly fat, protein and ash contents after 90 days of conservation. The fatty acid profile was dominated by PUFA for all the tested samples. Docosahexaenoic acid was the most abundant unsaturated fatty acid, followed by linoleic acid in GSO samples (20.86 ± 0.06% compared to 1.46 ± 0.05% in fresh sardine) and oleic acid in OO samples. Both atherogenic and thrombogenic indices decreased after the canning process in OO and GSO to less than 1. Thus GSO seems to improve the lipid nutritional quality in fresh sardine. In addition, the values for thiobarbituric acid and Total volatile base nitrogen did not exceed critical limits.

Systematics of European coastal anchovies (genus Engraulis Cuvier).

Reports of morphological differences between European anchovy (Engraulis cf. encrasicolus) from coastal and marine habitats have long existed in the ichthyologic literature and have given rise to a long-standing debate on their taxonomic status. More recently, molecular studies have confirmed the existence of genetic differentiation between the two anchovy ecotypes. Using ancestry-informative markers, we show that coastal anchovies throughout the Mediterranean share a common ancestry and that substantial genetic differentiation persists in different pairs of coastal/marine populations despite the presence of limited gene flow. On the basis of genetic and ecological arguments, we propose that coastal anchovies deserve a species status of their own (E. maeoticus) and argue that a unified taxonomical framework is critical for future research and management.

Microsatellite length variation in candidate genes correlates with habitat in the gilthead sea bream Sparus aurata.

The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several Mediterranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental conditions are less subject to rapid and stressful change. Whether these coexisting strategies are phenotypically plastic or include a role for local adaptation through differential survival needs to be determined. Here, we explore the genetic basis of alternate habitat use in western Mediterranean populations of the gilthead sea bream (Sparus aurata). Samples from lagoonal and open-sea habitats were typed for three candidate gene microsatellite loci, seven anonymous microsatellites and 44 amplified fragment length polymorphism markers to test for genotype-environment associations. While anonymous markers globally indicated high levels of gene flow across geographic locations and habitats, non-neutral differentiation patterns correlated with habitat type were found at two candidate microsatellite loci located in the promoter region of the growth hormone and prolactin genes. Further analysis of these two genes revealed that a mechanism based on habitat choice alone could not explain the distribution of genotype frequencies at a regional scale, thus implying a role for differential survival between habitats. We also found an association between allele size and habitat type, which, in the light of previous studies, suggests that polymorphisms in the proximal promoter region could influence gene expression by modulating transcription factor binding, thus providing a potential explanatory link between genotype and growth phenotype in nature.

Spinal deformities in the black-striped pipefish Syngnathus abaster (Pisces, Syngnathidae) from the Tunis North Lake, Tunisia.

Spinal deformities are seen in fishes. Deformities in the family Syngnathidae is rarely reported. Spine curvatures in natural population of pipefish, Syngnathus abaster are reported from the Tunis North Lake. The species is euryhaline and occurs along the Mediterranean coasts. Four hundred specimens of S. abaster were collected from January 2006 to December 2007 from the Tunis North Lake. Two specimens with skeletal abnormalities were described for the first time. X-rays radiographies revealed several vertebral deformities for each deformed specimen, especially at five curvation places of the caudal part. Several factors are believed to be the cause of spinal deformities of S. abaster in the Tunis North Lake, such as environmental disturbances, parasitism infection and nutritional factors.

[Strong genetic differentiation of the gilthead sea bream Sparus aurata (L., 1758) between the two western banks of the Mediterranean]. / Forte différenciation génétique de la daurade Sparus aurata (L., 1758) entre les deux rives de la Méditerranée occidentale.

We characterised four samples of gilthead sea bream from the two western Mediterranean banks with three microsatellite loci and two RAPDs systems. Contrarily to what could be predicted for a highly mobile species with a planktonic larval dispersal phase, we observed a strong and significant genetic differentiation at all loci between the two banks (F(st)=0.069(***)), whereas two samples from the Gulf of Lions were almost identical (F(st)=0.003 ns) while the two from the Gulf of Annaba displayed varied levels of differentiation according to the molecular marker considered. RAPDs showed a similar trend as microsatellites. The reasons for this surprisingly strong genetic differentiation, as compared to what has been observed in other species over comparable geographical distance, may be sought for either in a smaller as suspected larval dispersal, or in the non-neutrality of the loci studied.

Atherina punctata and Atherina lagunae (Pisces, Atherinidae), new species in the Mediterranean Sea. 1. Biometric investigations of three Atherinid species.

Discriminative canonical analysis of 87 biometric parameters in the marine and lagoon atherinids of 'Atherina boyeri' complex from the Mediterranean Sea helps defining three distinct atherinid groups: marine punctuated, marine unpunctuated and lagoon atherinids. Each atherinid group constitutes a clearly independent original entity. Besides, each one is a more or less heterogeneous group with geographical disparities, characterising specimen collected from France and Tunisia. Concordance of biometric, biochemical and genetic results as well help define two new species of atherinids: Atherina punctata = punctuated marine atherinids, and Atherina lagunae = atherinids living in lagoon environments.

Atherina punctata and Atherina lagunae (Pisces, Atherinidae), new species found in the Mediterranean sea. 2. Molecular investigations of three Atherinid species.

On the basis of morphoanatomical parameters, the sand smelt species (Atherina boyeri Risso, 1810) is viewed as a highly polymorphic complex. In this study, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 88 individuals from Tunisia and France. The correlation between the results of statistical analysis of the sequence data using a variety of tree-building algorithms and morphoanatomical analyses demonstrated the subdivision into three putative species: A. boyeri, which only includes non-punctuated fishes, A. punctata, which corresponds to punctuated fishes and A. lagunae, which corresponds to atherines living in lagoons.