Fauna asociada y efecto de los balanos epibiontes al crecimiento relativo e índices reproductivos de Stramonita haemastoma (Gasterópoda: Muricidae)

To better understand the impacts of biofouling on the biological processes of the basibiont, the effects of epibiotic barnacles on the relative growth and reproductive indices of Stramonita haemastoma (Linnaeus, 1767) were assessed. A total of 1035 specimens were collected monthly for one year from Bizerta Channel (northern Tunisia). Endobiotic species comprised the lithophagous bivalves Lithophaga aristata and Rocellaria dubia of different sizes, communicating with the outside through tiny perforations. Intra-shell tunnels and galleries also sheltered annelids and sipunculids. Epibiotic species comprised algae and highly diversified invertebrates represented by crustaceans, polychaetes, molluscs, echinoderms, ascidians, sponges, bryozoans and sipunculids, with barnacles being the most common group. Comparison of growth features between non-fouled and fouled S. haemastoma revealed higher growth in non-fouled specimens. Differences in reproductive condition indices were detected in few months, being mostly higher in non-fouled snails, but showed no asynchrony in the spawning period for either fouled or non-fouled gastropods hosts.Para mejorar la compresión de los impactos del biofouling en los procesos biológicos de los basibiontes, se ha evaluado los efectos de los balanos epibiontes en el crecimiento relativo y en los índices reproductivos de Stramonita haemastoma (Linnaeus, 1767). Se recogieron un total de 1032 especímenes mensualmente, durante un año, en el canal de Bizerta (norte de Túnez). Las especies endobióticas estaban compuestas por los bibalvos litófagos Lithophaga aristata y Rocellaria dubia, de diferentes tamaños, que se comunicaban con el exterior a través de pequeñas perforaciones. Los túneles y galerías del interior de la concha también albergaban anélidos y sipuncúlidos, siendo los balanos el grupo más común. La comparación del crecimiento entre los gasterópodos con y sin fouling mostró un mayor crecimiento en los S. haemastoma sin fouling. Las diferencias en los índices reproductivos se detectaron en pocos meses, siendo mayor en los caracoles no invadidos por el fouling, pero ninguno de los gasterópodos hospedadores mostró asincronía en el periodo de desove

Imposex level and penis malformation in Hexaplex trunculus from the Tunisian coast

Volume: 24Start Page: 79End Page: 8

Monitoring of coastal pollution using shell alterations in the false limpet Siphonaria pectinata

International audienceLipid peroxidation level (LPO), shell biometry, shape, elemental content, and microstructure were studied in three populations of Siphonaria pectinata in the complex lagoon-channel of Bizerte across a coastal pollution gradient (northern Tunisia). LPO was found in higher concentrations in harbour populations, and shells had centred apex and were flattened. Shells were also thicker, particularly in the inner layer, with many fibrous inter-beds formed. Difference in crystallization pattern was observed in numerous shells from all three populations, being more common in harbours. From the control station to the contaminated stations, shell elemental changes were observed, with a decrease in Ca, P, Sr, and S and an increase in Cl, Cd, Cu, Fe, and K. All of these findings suggested that shell alterations could be used as a good biomarker for coastal contamination

Shell alterations in Hexaplex trunculus collected in the vicinity of an impacted zone by industrial marine discharges (Gabès, Southern Mediterranean)

International audienceUsing the gastropod Hexaplex trunculus, a comparative study of the shell characteristics (morphometrics, microstructure and elemental composition) was carried out in the vicinity of Gabès city (Chatt Essalem, CE) which is known as seriously affected by industrial pollution, and two control zones (Ghanouche, GH and Teboulbou, TB). Gastropods from CE had larger, thicker and heavier shells, associated with bigger apertures and slighter soft bodies. Scanning electron microscope (SEM) revealed the presence of three shell layers having a crossed lamellar structure. The inner layer was thinner, while the median layer was thicker in snails from CE, suggestive of the ability of H. trunculus to remodel the shell microstructure accordingly. Moreover, the median and inner layers were marked by the presence of fibrous interbeds that were numerous and thicker in shells from CE. In this site, shell elemental alteration was also observed with a decrease in Ca, P, S, K and O contents against an increase in C, Cl and Mg compared to control sites. This investigation was in agreement with previous studies and further suggests the deleterious effect of coastal pollution generated by various industrial units implemented around Gabès city on marine organisms

A comparative study of the thermal behaviour of phosphate washing sludge from Tunisia and Morocco

International audienc

Effect of temperature and clay addition on the thermal behavior of phosphate sludge

International audienc