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Digitisation of specimens (e.g. zoological, botanical) can provide access to advanced morphological and anatomical information and promote new research opportunities. The micro-CT technology may support the development of "virtual museums" or "virtual laboratories" where digital 3D imaging data are shared widely and freely. There is currently a lack of universal standards concerning the publication and curation of micro-CT datasets. The aim of the current project was to create a virtual gallery with micro-CT scans of individuals of the marine gastropod Hexaplex trunculus, which were maintained under a combination of increased temperature and low pH conditions, thus simulating future climate change scenarios. The 3D volume-rendering models created were used to visualise the structure properties of the gastropods shells. Finally, the 3D analysis performed on the micro-CT scans was used to investigate potential changes in the shell properties of the gastropods. The derived micro-CT 3D images were annotated with detailed metadata and can be interactively displayed and manipulated using online tools through the micro-CT virtual laboratory, which was developed under the LifeWatchGreece Research Infrastructure for the dissemination of virtual image galleries collection supporting the principles of FAIR data.

Este artículo contiene 12 páginas, 4 figuras, 1 tabla., Background: Classic ecological formulations of predator–prey interactions often assume that predators and prey interact randomly in an information-limited environment. In the feld, however, most prey can accurately assess predation risk by sensing predator chemical cues, which typically trigger some form of escape response to reduce the probability of capture. Here, we explore under laboratory-controlled conditions the long-term (minutes to hours) escaping response of the sea urchin Paracentrotus lividus, a key species in Mediterranean subtidal macrophyte communities. Methods: Behavioural experiments involved exposing a random sample of P. lividus to either one of two treatments: (i) control water (fltered seawater) or (ii) predator-conditioned water (with cues from the main P. lividus benthic predator—the gastropod Hexaplex trunculus). We analysed individual sea urchin trajectories, computed their heading angles, speed, path straightness, difusive properties, and directional entropy (as a measure of path unpredictability). To account for the full picture of escaping strategies, we followed not only the frst instants post-predator exposure, but also the entire escape trajectory. We then used linear models to compare the observed results from control and predators treatments. Results: The trajectories from sea urchins subjected to predator cues were, on average, straighter and faster than those coming from controls, which translated into diferences in the difusive properties and unpredictability of their movement patterns. Sea urchins in control trials showed complex difusive properties in an information-limited environment, with highly variable trajectories, ranging from Brownian motion to superdifusion, and even marginal ballistic motion. In predator cue treatments, variability reduced, and trajectories became more homogeneous and predictable at the edge of ballistic motion. Conclusions: Despite their old evolutionary origin, lack of cephalization, and homogenous external appearance, the trajectories that sea urchins displayed in information-limited environments were complex and ranged widely between individuals. Such variable behavioural repertoire appeared to be intrinsic to the species and emerged when the animals were left unconstrained. Our results highlight that fear from predators can be an important driver of sea urchin movement patterns. All in all, the observation of anomalous difusion, highly variable trajectories and the behavioural shift induced by predator cues, further highlight that the functional forms currently used in classical predator–prey models are far from realistic., The Spanish Ministry of Science and Innovation funded this research (project CTM2010-22273-C02, CTM2017-86695-C3-1-R, CTM2017-86695-C3-3-R, and CGL78156-C2-R1). JFP acknowledges fnancial support from the Spanish Ministry of Education (scholarship AP2008-01601) and the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 795315.

Small-scale fisheries have a high socioeconomic importance for local communities. Therefore, ensuring the sustainability of fisheries resources would contribute for the socioeconomic development of fisheries communities. In this study, traps produced from plastic waste recycle materials which can be used in fishing of economically valued whelks (Hexaplex trunculus and Bolinus brandaris) that are used as natural bait in angling and longline fishing were investigated. These traps in different sizes were examined at the depths of 3-8 m in the Urla coasts of Izmir Bay, Turkey. The soaking times of traps were between 10-48 hours. The same amounts of baits (Sardina pilchardus) were equally placed in all traps. Catch per unit efforts (CPUE) of traps were calculated between 7-34 individuals/trap per day. The experimented traps were found successful for whelks fishing. Traps yield high quality and economically valued catches, related with restricted bycatch and low impact on habitat. Therefore, these traps can be suggested as alternative fishing gears designed for trap fisheries for whelks. This paper provides valuable knowledge for fisheries managers and decision makers to ensure the sustainability of local fisheries resources and small-scale fisheries.

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. The 3D model dataset can be also further processed through volume rendering and morphometric analysis. The success of micro-CT as a visualisation technique depends on several methodological manipulations, including the use of contrast enhancing staining agents, filters, scanning mediums, containers, exposure time and frame averaging. The aim of this study was to standardise a series of micro-CT scanning and 3D analysis protocols for a marine gastropod species, Hexaplex trunculus. The analytical protocols have followed all the developmental stages of this gastropod, from egg capsules and embryos to juveniles and adults.

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. This protocol aims to standardise micro-CT scanning and 3D analysis for the marine gastropod species Hexaplex trunculus.

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. This protocol aims to standardise micro-CT scanning procedures for the egg capsules of the marine gastropod species Hexaplex trunculus.

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. This protocol aims to standardise micro-CT scanning procedures for embryos and juveniles of the marine gastropod species Hexaplex trunculus.

The optimal technique for determining the chemical compositions of archaeological purple pigments and dyes from molluscan sources is the high-performance liquid chromatography (HPLC) method. This technique has been applied to the qualitative and quantitative multi-component fingerprinting of purple pigments extracted from various Mediterranean Muricidae molluscs, commonly known as Murex sea snails. The results on modern and archaeological purple pigments show that the colourants in these samples belong to three related chemical groups: indigoids, indirubinoids, and isatinoids. Discoveries on archaeological artifacts from the ancient Near East made by this laboratory include: decoding the ancient optimal method of purple-dyeing; detection of the purple pigment painted on a 2500-year old King Darius I marble jar; identifying 2000-year old biblical Argaman and Tekhelet dyeings from Masada. La meilleure méthode pour déterminer la composition chimique des pigments et des teintures archéologiques pourpres issus de mollusques est la chromatographie en phase liquide haute performance. On a utilisé cette technique pour l’analyse qualitative et quantitative des différents éléments constituant la signature de la pourpre extraite des différentes variétés de mollusques du type Muricidae rencontrées en Méditerranée, plus communément connues sous le nom de Murex. Les résultats montrent que les colorants rentrant dans la composition de la pourpre appartiennent à trois classes chimiques : les indigoïdes, les indirubinoïdes et les isatinoïdes. Au nombre des découvertes réalisées par notre laboratoire sur des objets archéologiques provenant du Proche-Orient, on retiendra la mise en évidence du procédé antique optimal pour obtenir la teinte pourpre ; la découverte d’un pigment pourpre sur une jarre royale de marbre vieille de 2500 ans et datant de l’époque du roi perse Darius Ier ; l’identification de l’Argaman et du Tekhelet bibliques vieux de 2000 ans et provenant de Masada. Η βέλτιστη τεχνική για τον καθορισμό της χημικής σύνθεσης αρχαιολογικών πορφυρών χρωστικών ουσιών και βαφών από μαλάκια είναι η μέθοδος της υγρής χρωματογραφίας υψηλής απόδοσης. Η τεχνική αυτή έχει εφαρμοστεί για την ποιοτική και ποσοτική ανάλυση πορφυρών χρωστικών ουσιών που προέρχονται από διάφορα μεσογειακά μαλάκια Muricidae, που είναι ευρέως γνωστά ως murex. Τα αποτελέσματα σε σύγχρονες και αρχαιολογικές πορφυρές βαφές δείχνουν ότι οι χρωστικές ουσίες στα δείγματα αυτά ανήκουν σε τρία συσχετιζόμενα χημικά σύνολα: τα σχετικά με τη βαθυγάλανη, την ερυθρή και την κόκκινη βαφή. Οι ανακαλύψεις σε αρχαιολογικά αντικείμενα από την αρχαία Εγγύς Ανατολή που έγιναν σε αυτό το εργαστήριο περιλαμβάνουν: την αποκωδικοποίηση της αρχαίας βέλτισης μεθόδου για την πορφυρή βαφή· την ανίχνευση πορφυράς χρωστικής ουσίας πάνω σε ένα μαρμάρινο αγγείο του βασιλιά Δαρείου Α΄ ηλικίας 2500 ετών· την ταύτιση των βιβλικών βαφών Αργκαμάν και Τεκελέτ, ηλικίας 2000 ετών, από τη Μάσαδα.

The preliminary shell growth rate of Hexaplex trunculus (Linnaeus, 1758) after long-term exposure to a range of future ocean acidification conditions

The present study aimed to elucidate the causal factor of tentacular malformations observed in Stramonita haemastoma. For this purpose, an annual, spatial and interspecific survey of the tentacular malformations was conducted in addition to the experimental semi-amputation of the tentacles of S. haemastoma. This study reports, for the first time, the occurrence of tentacular malformations in S. haemastoma collected for one year from the Bizerta Channel. Tentacle malformations were detected in 12 out of 17 Mediterranean and Atlantic coastal sites. Besides S. haemastoma, two sympatric muricid species (Hexaplex trunculus and Bolinus brandaris) also showed the occurrence of tentacular malformations. The experimental semi-amputation of the tentacles of S. haemastoma confirmed the capacity of regeneration in this gastropod; however, the process was often deficient and the neo-formed anterior segment was usually shorter, thinner and provided with a small ocellus. Sometimes, individuals were unable to regenerate a number of structures like the posterior segment and the ocellus, which may explain the tentacular malformations observed previously in S. haemastoma. This study provided new data about the incidence of tentacular malformations in marine gastropods. Our results further demonstrate the capacity of regeneration in S. haemastoma, which can be used as a new model in regeneration studies.

Occurrence of traditional (PBDEs) and novel (HBB, PBEB, DBDPE) brominated flame retardants, as well as the natural compounds of MeO-PBDEs, were studied in a shellfish species (Hexaplex trunculus) sampled from Bizerte Lagoon. PBDE and MeO-PBDE mean concentrations in murex soft tissues were 187 and 264 ng g−1 lw respectively. The alternative flame retardants were not identified. The sum of PBDE and MeO-PBDE levels recorded in murex from the investigated aquatic ecosystem were comparable or a relatively lower than those reported for other organisms from other regions across the world. The amount of PBDE and MeO-PBDE concentrations from the Bizerte Lagoon recorded in murex were comparable or a relatively lower than those recorded from other areas across the world for other species. There is not a danger to the population health with regard to PBDE intakes associated with the consumption of murex in Bizerte city. We believe that this is the first study of the analysis of these pollutants in marine gastropod mollusks from Tunisian aquatic areas. © 2020, Springer Science+Business Media, LLC, part of Springer Nature., The Spanish Ministry of Science and Innovation (CEMAGUA-CGL2007-64551/HID) and the Tunisian Ministry of Higher Education and Scientific Research supported this study. The authors are thankful to R. Chaler, D. Fangul, and M. Comesaña for their help at the mass spectrometry work.

Increased atmospheric CO 2 produced by anthropogenic activities will be absorbed by the oceans over the next century causing ocean acidification and changes in the seawater carbonate chemistry. Elevated CO 2 causes sublethal physiological and behavioural responses on the locomotion and foraging behaviour of marine organisms. This study aims to investigate the independent and synergistic effects of long term exposure to low pH and increased temperature on the feeding behaviour of two gastropod species, Hexaplex trunculus and Nassarius nitidus , both in adults and juveniles. Gastropods were maintained under controlled conditions of temperature (ambient = 20°C, increased = 23°C) and pH (ambient = 8, low = 7.6) for 2.5 years. The percentage of animals which successfully reached their food, the response time until gastropods began moving, the total duration until they reached food and the total distance covered, were measured. Speed and path index (i.e how straightforward the movement is) were estimated as means of foraging efficiency. Increased temperature (under ambient pH) resulted in faster responses, a shorter duration until food was reached and a higher speed in H. trunculus adults. H. trunculus (both adults and juveniles) were less successful in reaching their food source under low pH and ambient temperature in comparison to all other treatments. The response time, duration, speed and path index were not affected by low pH (at ambient or increased temperature) for H. trunculus adults and juveniles, as well as for N. nitidus . The foraging performance of juveniles hatched and developed under low pH (either at ambient or increased temperature) was more effective than adults of the same species, thus indicating a degree of acclimation. Also, the scavenger N. nitidus was more successful and responded faster in reaching carrion than the predator H. trunculus , whereas no significant effects were observed for N. nitidus under low pH.

The present study reports morphometric relationships and discusses the relative growth in the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). A total of 11 morphometric parameters (eight linear variables: shell length, shell width, total aperture length, aperture length, aperture width, spire length, spire width and siphonal canal length; three ponderal variables: total weight, soft parts weight and shell weight) were analysed in both species. The analyses comprised numerous individuals of both sexes and with broad size ranges (H. trunculus: 10.7–82.8 mm shell length;B. brandaris: 14.6–107.7 mm shell length), fairly representative of the populations from the Ria Formosa lagoon. In general,B. brandarisexhibited greater morphological plasticity and higher variability in shell shape compared withH. trunculus. In both species, the vast majority of morphometric relationships displayed positive allometries, distantly followed by negative allometries and by isometries. AlthoughH. trunculusandB. brandarisare known to lack external sexual dimorphism, several morphometric relationships revealed significant differences in the type of growth between sexes, which should be further confirmed using more powerful techniques, such as geometric morphometric analyses of shell shape.

The aim of this study was to compare imposex and butyltin compounds (BTs) data, collected before and after the organotin ban in 2008, in order to assess temporal and spatial variation of the phenomenon, the decline of BT contamination, and the effects on Hexaplex trunculus population in the coastal area of the northern Adriatic Sea, close to the Venice Lagoon. Both in marine and in lagoon sites, the results obtained in 2013–2015 showed a significant decline in the incidence of imposex in respect to those from the 2002 survey. In 2002, lagoon samples exhibited Relative Penis Size Index (RPSI) higher than marine samples, whereas no differences were detected in the recent survey, when all RPSI values were below 0.6%. Vas Deference Sequence Index (VDSI) mean values were over 4 before the ban introduction and below this value after that, indicating more critical conditions for gastropod population in 2002 rather than in 2013-15. Percentage of sterile females was up to 69% in 2002, whilst in the more recent survey no sterile female was found. Range of BT concentrations in gastropods decreased from 252 to 579 to 16–31 ng∑BT/g d.w. BT body burdens varied according to a gender dependant pattern, with higher concentrations observed in females than in males. A first attempt to propose a classification based on BT impact on H. trunculus , according to the Water Framework Directive, revealed that most sites were in Bad ecological status before the ban and attained a Poor/Moderate status after that.

Volak Hexaplex trunculus se često koristi za praćenje onečišćenja morskog okoliša organokositrovim spojevima, u prvom redu tributilkositrom (TBT). Radi se o vrsti koja razvija imposeks već pri niskim razinama onečišćenja TBT-om. U ovoj disertaciji predstavljeni su rezultati istraživanja povezanosti imposeksa kod volka H. trunculus i onečišćenja TBT-om provedenih na području srednjeg dijela hrvatskog Jadrana na 7 postaja tijekom 2014. godine i 12 postaja tijekom 2015. godine. Kod svih istraživanih populacija zabilježena je pojava imposeksa, a mjerenjem masenog udjela TBT-a u tkivu volka H. trunculus i sedimentu potvrđena je i prisutnost onečišćenja TBT-om. Istraživanjem provedenim 2014. godine nije potvrđena povezanost onečišćenja TBT-om s aktivnošću odabranih biomarkera (katalaza, glutation S- transferaza, glutation reduktaza, malondialdehidi, karbonili, acetilkolinesteraza), iako je uočena povećana aktivnost glutation reduktaze i glutation S-transferaze kod volaka s jače onečišćenih postaja. Istraživanje učinkovitosti zabrane korištenja TBT-a, koja je u Republici Hrvatskoj na snazi od 2006. godine, provedeno je 2015. godine na istim postajama na kojima je istraživanje imposeksa provedeno i 2005. godine, kategoriziranim prema razini brodske aktivnosti (nautičke marine, lučice, uvale koje se koriste samo sezonski, referentne postaje koje se rijetko koriste). Rezultati istraživanja sugeriraju da je u desetogodišnjem razdoblju došlo do smanjenja razine onečišćenja TBT-om. Ipak, smanjenje nije rezultiralo oporavkom istraživanih populacija budući da je kod svih utvrđen visoki udio imposeksa kao i povećanje udjela sterilnih ženki. U svrhu potencijalnog korištenja vrste H. trunculus kao bioindikatora u ocjeni ekološkog stanja priobalnih voda u okviru Direktive o vodama, a s obzirom na onečišćenje voda TBT-om i posljedičnim razvojem imposeksa, predložene su granične vrijednosti omjera ekološke kakvoće (OEK) . Istraživanjem stabilnih izotopa dušika (Ł15Nair) i ugljika (Ł13CVPDV) u tkivu volka H. trunculus nije potvrđena povezanost sadržaja stabilnih izotopa sa stupnjem onečišćenosti istraživanih postaja TBT-om. Banded murex Hexaplex trunculus is used in the marine environment monitoring of organotin pollution, as this species develops imposex at very low tribytiltin (TBT) concentration. In this thesis relationship between imposex in H. trunculus and TBT pollution was investigated along the central Croatian Adriatic coast at 7 sites in 2014 and 12 sites in 2015. Imposex was recorded at all investigated sites on which also TBT pollution was demonstrated, both in tissue of H. trunculus and in sediment. Investigations performed in year 2014 showed no connection between degree of TBT pollution and activity of specific biomarkers (catalase, glutathione S-transferase, glutathione reductase, malondialdehydes, carbonyls, acetylcholinesterase) in gastropod, although the increased activity of glutathione reductase and glutathione S-transferase in banded murex from the most polluted sites was observed. Investigation on effectiveness of the ban of organotin compounds in antifouling coatings, which is in force in the Republic of Croatia since 2006, was performed in 2015 at the same sites previously investigated in 2005 which were categorized according to intensity of boating activities to nautical marinas, village harbours, sheltered bays and reference sites. Obtained results suggested that TBT pollution has decreased in this ten years period. However, this decrease was not sufficient for the recovery of H. trunculus populations, since in 2015 all populations showed high degree of imposex and even higher number of sterile females than in 2005. The Ecological Quality Ratio (EQR) values for the potential use of imposex in H. trunculus as bioindicator in assessment of the ecological status of coastal waters regarding TBT pollution in the frame of Water Framework Directive (WFD) are proposed. Relationship between carbon (Ł13CVPDV) and nitrogen (Ł15Nair) isotopes content in H. trunculus and degree of TBT pollution was not established.

International audience; Although the banded murex Hexaplex trunculus (Linnaeus, 1758) has no dispersal stage, it is widely distributed in a relatively broad range of habitats. These features make it a particularly suitable model to reconstruct the history of the fragmentation of its geographical range. We investigated its genetic structure from the eastern Mediterranean to the Atlantic coast, by sequencing a nuclear intron (i29) and a mitochondrial marker (cox1). We found strong genetic differentiation between all population pairs, congruent with the absence of a dispersing larval stage. A deep phylogeographical break separated two parapatric lineages, a western lineage (I) and an eastern one (II). The two lineages were separated by a vicariance event dated to the Pliocene by both markers, analysed independently. They co-occur in southern Italy and in the Siculo-Tunisian straight, where some individuals display recombined genotypes (lineage I for one marker, lineage II for the other), suggesting that introgression occurred in sympatric populations. We were unable to determine whether the vicariance was across the STS or located further east across the Peloponnese Arc, but the presence of lineage I in the northern Adriatic is more parsimoniously explained by a more eastern vicariance. Lineage I displayed a stronger signal of demographic expansion than lineage II, and its expansion was estimated to be more recent. This result, which has been reported in other marine species, suggests less drastic conditions for the eastern (and possibly also the central) Mediterranean benthos than for western populations during past climatic oscillations. The parapatric distribution still observed today suggests that human exploitation of this snail, which dates back to Antiquity, did not result in efficient introductions among basins, although present-day introductions were recently reported in the Bay of Biscay.

A new statistical method based on a stochastic dynamic model is proposed to assess population abundances of murcid species at scales relevant to both Ancient and Modern artisanal, coastal fisheries. Motivated by the long-term goal of reconstructing the dynamics of exploited murex populations during Antiquity, the objective was to quantify the population density of the banded-dye murex, Hexaplex trunculus (Linnaeus, 1758) from successive captures with baited traps, using a method similar to the technique employed in the Mediterranean purple dye industry. A stochastic model simulating cumulative captures while taking into account high variability was developed and calibrated with data acquired during a field experiment conducted on Crete Island, near Heraklion. Sampling devices were deployed in two shallow water habitats. The traps’ catchability and the Effective Area of Attraction were estimated using the individual speed and behavioural response toward the bait observed during independent laboratory experiments. The average density of H. trunculus was estimated at 2.2 ± 1.4 SE individuals per square meter, with no significant differences between seagrass and rocky habitats, respectively. The clearing time (the time to catch all individuals within reach of the trap) of the successive experiments was 84 ± 6 SE hours, on average. This means that clearing ca. 0.4 ha of subtidal area would be necessary to produce ca. 1.0 g of pure dye pigment. While the method is discussed here with respect to a particular historical context, it is generalizable to making population abundance estimates for other species such as whelks, in modern fisheries.

Copper, Zn, and Cd were analyzed in the soft tissues of the edible gastropod Hexaplex trunculus collected from seven localities along the Tunisian coast. The body concentration of these metals was significantly different depending on the gender and site. Copper and Zn varied, respectively, from 47.70 to 343.64 μg/g dry weight (dw) and 149.46 to 530.44 μg/g dw, being higher in males. Cadmium varied from 0.22 to 18.95 μg/g dw and was always higher in females. Overall, the highest concentrations of the three metals were all recorded in Gabès fishing harbor. Comparison of metal concentrations with the European standards compiled by the Food and Agriculture Organization showed that values exceeded standards in several localities. Imposex had been previously recorded in H. trunculus along the Tunisian coast; however, it does not seem to be related with Cu, Zn, and Cd pollution because the body concentration of these metals is not correlated with imposex degree. Nevertheless, interactive effects resulting from the combination of different pollutants and other stressors cannot be disregarded.

In 1684 the Italian scientist Francesco Redi published one of the first detailed studies on land gastropods. It included the mating and functional anatomy of limacid slugs, functional anatomy of helicid snails and morpho-anatomical comparisons of land and marine slugs and snails. His research was based on a few marine species (an unidentified gastropod, the neogastropod Hexaplex trunculus and aplysiid opisthobranchs), several land snails (including the large helicid Helix lucorum) and some limacid slugs (probably different species of the Limax corsicus group and perhaps Limacus flavus). Redi's investigations are generally accurate and his description of slug mating is much more detailed than the earlier account by Martin Lister. However, his survey also contains minor oversights and mistakes: he did not identify major organs of mollusc anatomy (radula, salivary glands and certain genital structures), his illustration of mating slugs is unrealistic and he overlooked important anatomical differences between marine and land slugs. His most remarkable oversight is hermaphroditism: although he observed slug mating, knew that no differences existed between partners, and was probably aware of earlier literature on the androgynous nature of land snails, he failed to conclude that they are hermaphrodite.

The aim of this paper is to bring to light the knowledge of marine diversity of invertebrates in Gabes gulf. The spatial distribution of the megabenthic fauna community in Gabes gulf (Tunisia, Eastern Mediterranean Sea), together with the bottom type and vegetation cover, were studied. The abundance of the megabenthic fauna was represented by eight groups: Echinodermata (38%), Crustacea (21%), Tunicata (19%), Mollusca (13%), Porifera (4%), Cnidaria (3%), Bryozoa, and Annelida (2%). It was spatially more concentrated in the coast area of the gulf than in the offshore waters. This area, especially, in Southern Kerkennah, North-est of Gabes and North-east of Djerba appeared to be in a good ecological condition hosting a variety of species like the pagurids Paguristes eremita and Pagurus cuanensis, the brachyura Medorippe lanata, Inachus doresttensis, the Gastropoda Hexaplex trunculus, Bolinus brandaris, Aporrhais pespelecani, andErosaria turdus, the Bivalvia Fulvia fragilis, the Echinoidea Psammechinus microtuberculatus, Holothuria polii,Ophiothrix fragilis and Antedon mediterranea, and the AscidiaceaAplidium cf. conicum, Didemnum spp, and Microcosmus exasperatus. The species’ compositions of the megabentic fauna community showed clearly that the spatial analysis represented the differences between the community of these two regions (inshore waters and offshore waters). These differences were closely related to peculiar characters of the fauna and biotopes (depth, bottom type and vegetation cover community). The results of the present study should be considered as a necessary starting point for a further analysis of priceless benthic fauna contribution to the marine environment and its organisms. This work was undertaken within the framework of research activities in the “Marine Living Resources” laboratory of the National Institute of Marine Sciences and Technologies (INSTM), financed by the Tunisian Ministry of Agriculture and Fisheries.

This study estimated the age of Hexaplex trunculus (Gastropoda: Muricidae) by analysing operculum growth marks. Surface striae and adventitious layers were counted in opercula of H. trunculus from the Ria Formosa Lagoon (southern Portugal) and from the Bizerte Lagoon (northern Tunisia), and in aquacultured individuals used for validation of the ageing technique. Operculum growth features were also compared between H. trunculus populations under contrasting environmental conditions (namely seawater temperature). Despite high inter-individual variability, all H. trunculus populations displayed a clear increasing trend in the number of striae and layers with increasing specimen size. The operculum marginal growth revealed that opercular deposition is not annual. Instead, a few growth marks are formed in the operculum each year, which was confirmed with reared specimens. In both ageing methods, considerable variation in the number of counts at a determined shell length indicates that operculum growth marks should be interpreted cautiously because they might not correspond accurately with individual age. Because of the subjectivity inherent to either method, counting striae and layers in opercula only provides rough age estimates of H. trunculus. published

Marine gastropods, exposed to anthropogenic pollution, accumulate high chemical concentrations in their tissues, especially in the digestive glands. An evaluation of the impacts of cadmium (Cd) and permethrin (Perm), coupled with reproductive events (pre-spawning and post-spawning phase) throughout the year, was attempted by measuring catalase (CAT), a biomarker of defence, on Hexaplex trunculus experimentally exposed for 48 or 96 h. Specimens of gastropods were sampled from Bizerta Lagoon (Tunisia). The results show that CAT activity increased in gastropods exposed to the three cadmium concentrations (C1 Cd, 100 μg L(-1); C2 Cd, 200 μg L(-1); and C3 Cd, 300 μg L(-1)) and to the three permethrin doses (C1 Perm, 100 μg L(-1); C2 Perm, 150 μg L(-1); and C3 Perm, 200 μg L(-1)) tested. A decrease in CAT was noted in the digestive gland of the H. trunculus exposed to permethrin at the concentration of 200 μg L(-1) during the pre-spawning and post-spawning phases. H. trunculus in post-spawning was more sensitive to cadmium and permethrin than in the pre-spawning phase. The biochemical responses to pollutants (cadmium and permethrin) represented by CAT may act as a biomarker of exposure in this species.

Imposex and butyltin concentrations were assessed in Hexaplex trunculus, Conus mediterraneus, Cyclope neritea and Nassarius mutabilis from Menzel Jemil, and H. trunculus and Stramonita haemastoma from the Bizerta channel. All females of the five species exhibited the characteristic development of male sex organs (penis and/or vas deferens). In Menzel Jemil, H. trunculus and C. mediterraneus exhibit similar imposex levels and were most affected (VDS reading 3-4). The development of a bud penis or a vas deferens sequence behind the right ocular tentacle was reported in Cyclope neritea and N. mutabilis (VDS 1). The concentration of tributyltin (TBT) was similar for the four species. The monobutyltin (MBT) was only detected in C. mediterraneus while the dibutyltin (DBT) was found in all gastropods at similar proportions as TBT. In the Bizerta channel, imposex levels were similar in both H. trunculus and S. haemastoma but imposex degree was higher in H. trunculus. This finding was confirmed by higher TBT concentration recorded in female of H. trunculus. These results suggested that H. trunculus is the more suitable bioindicator for monitoring TBT pollution.

This study investigates the reproductive cycle, size at first sexual maturity and biochem- ical composition of Hexaplex trunculus from the Bizerte lagoon (northern Tunisia). Overall, females predominated over males, resulting in an unbalanced sex ratio of 1.2:1. Males dominated in the smaller size classes ( 50 mm SL). The gonad developmental stages and the gonadosomatic index (GSI) indicated that H. trunculus apparently has an annual reproductive cycle with extended periods of gonadal activity. In both sexes, examination of the appearance of the gonads showed that gamete release occurred mainly from March to May (with an apparent spawn- ing between March and April), followed by a period of empty gonads between June and August. Sexual maturity occurred at smaller sizes in males (SL50 = 41.02 mm SL) than in females (SL50 = 50.47 mm SL). The contents of protein, lipids and carbohydrates were invariably greater in the gonads than in the foot, confirming the key role of the reproductive tissues in energetic storage. The monthly variation in protein, lipids and carbohydrates in the gonads followed the oscillation in the relative proportion of developed gonads and in the GSI, reflecting energetic mobilisation during mat- uration and spawning. Overall, the data gathered in this study constitutes valuable baseline informa- tion for making preliminary recommendations to the fishing community targeting H. trunculus in the Bizerte lagoon. Further studies and more solid data on the reproductive cycle of the species are required before definitive management measures for this locally important artisanal fishery can be proposed.

Spawning, intracapsular development, and juvenile growth of Hexaplex trunculus were investigated in the laboratory. Each female deposited nightly an average of 138.83 ± 58.70 yellowish egg capsules per spawn. Each capsule contained 358.57 ± 102.45 eggs with an average diameter of 207.23 ± 18.18 µm. Observations on the intracapsular development showed that H. trunculus is a spiralian unequal-cleaving gastropod, with polar lobes being extruded at early segmentation. Embryos develop within the egg capsule through the provision of nurse eggs as an extraembryonic source of nutrition. Hatching occurred after 52 d of incubation. However, the hatchlings were not completely metamorphosed because velum was still present. At this moment, the average of shell length was 1.04 ± 0.13 mm (n = 107). The average number of hatchlings per capsule was 14.73 ± 4.40 including 3.4% malformed individuals. During the first 5 mo of life, juveniles rapidly grew in shell length (growth rate = 3.56 mm/mo). However, in the remaining period (26 mo), growth rhythm decreased considerably (growth rate = 0.64 mm/mo). The weight growth rhythm was irregular with alternation between fast and slow increases observed over the rearing experiment. This kind of data could be useful for assessing the potential of this species for future molluscan aquaculture programs.

Two non-native muricid gastropods are known from The Netherlands since 2007, i.e. the American oyster drill Urosalpinx cinerea and the Japanese oyster drill Ocinebrellus inornatus. Both species reproduce and slowly increase their area of distribution. Eight vacant shells of another non-native muricid, Hexaplex trunculus, have been collected in 2007, 2008 and March 2009. The latter species from southern Europe has recently been observed along the western coast of Europe in areas of shellfish culture. Vacant shells of Haustellum brandaris and Ocenebra erinacea, two more non-native muricids, have been collected as well.

The purple dye murex Bolinus brandaris (Linnaeus, 1758) has been reported for the first time from O Grove inlet (Galicia, NW Spain) in 2007. The presence of the shell mounds shows that this Mediterranean gastropod is commonly recorded in O Grove inlet together with another exotic muricid: Hexaplex trunculus. To the extent of our knowledge, this is the northernmost record of this species on the NE Atlantic coast. This species is the newest entry into a list of 23 aquatic and benthic exotic molluscs species from Galician waters. Most of them are introduced marine species, which arrived accidentally, or not, in the Galician region as a consequence of ship transport, shellfish culture and trade.

Hexaplex trunculus (Linnaeus, 1758) is a gonochoric marine gastropod. Previous studies demonstrated that the biocide TBT (tributyltin) induced a sexual abnormality known as imposex (superimposition of male sexual characters onto females) in this whelk. Our study showed imposex in 19 stations out of 20 along the Tunisian coast. The frequency of imposex ranged from 0 to 100%. Among the 19 sites where the condition was found, 8 were considered as highly affected by imposex (VDSI > 3.7), 6 were moderately affected (VDSI > 1.3), and 4 were slightly affected (VDSI > 0). The most affected population was observed in the Bizerta Channel where the highest boating traffic was recorded; no imposex features were found in the Sea of Zarat where boating traffic was very low. Significant differences in imposex levels were obtained among sites with low, moderate, and high boating traffic. All the imposex indices values (I%, RPSI, RPLI, VDSI, FPL, and VDL) were significantly more elevated at sites with high boating traffic...

Imposex, namely the superimposition of male characteristics, such as penis and vas deferens, on females of gonochoristic gastropods is one of the most harmful effects of TBT on marine organisms. The development of such malformations on marine organisms have led to limitations in the use of TBT in antifouling paints in several countries. Regulation 782/2003 by the EU prohibits the application of organotin compounds. However, in other non EU Mediterranean countries, such as Croatia, the IMO convention has failed to be transposed into domestic legislation and TBT-based antifouling paints are still used. Different restrictions to TBT use and, consequently, likely different levels of TBT contamination between Italy and Croatia gave the cue to this work, whose aims are: (a) monitoring organotin compound levels and imposex degree in Hexaplex trunculus, a common gastropod in the Mediterranean Sea, and an exhibitor of imposex; (b) assessing the level of organotin compounds build-up in the visceral coil and in the rest of the soft body (ROSB) of this organism, in order to try to understand how H. trunculus metabolizes these pollutants; (c) investigating the relationship between organotin compound concentrations in tissues of H. trunculus and the level of imposex development. The results indicate that the incidence of imposex is still high in Italy (Lagoon of Venice) after more than 10 years from the ban of TBT-based antifouling paints. The sampling in Croatian coasts indicates that the absence of restrictions on the use of TBT is likely to cause very high levels of OTC contamination.

This work reports and illustrates secondary colonisation of Hexaplex (Trunculariopsis) trunculus shells by polychaetes in the Ria Formosa lagoon (Algarve coast—southern Portugal). Information is presented in terms of qualitative and quantitative data on epibiotic polychaetes, fouling frequency, degree of epibiosis, preferential areas for colonisation and incidence of shell damages. A total of 2,880 polychaetes belonging to 10 families were identified. Besides Spirorbidae (not quantified), the most abundant families were Serpulidae (67.5%), Sabellidae (10.2%), Sabellariidae (9.6%) and Cirratulidae (8.5%). From a total of 2,264 T. trunculus individuals analysed for epibiosis, 28.4% were non-fouled, 66.8% were intermediately fouled and 4.8% were heavily fouled. The fouling frequency, degree of epibiosis and incidence of damages in the shell spire increased markedly with T. trunculus shell length. Some epibiotic polychaetes were located preferentially on/or nearby particular features of T. trunculus shells, which probably facilitate settlement and tube construction, in addition to provide some protection against tube damage. The main consequences of epibiosis (benefits and disadvantages) for the gastropod basibiont (T. trunculus) are discussed. The present study apparently indicates that besides burrowing into soft bottom substrates, sporadic inter-tidal exposure and mutual predation on epibiosis, T. trunculus lacks other typical antifouling defence adaptations.

Mediterranean populations of the bivalve Arca noae were found to be specifically fouled by the demosponge Crambe crambe. The surface of the shells forms spines which favour settlement of the sponge larvae. The reproductive strategy of this symbiotic sponge contrasts with other Mediterranean sponges, which produce numerous small larvae, while Crambe crambe produces relatively small numbers of quite large larvae containing secondary metabolites. The selective shell fouling of Arca noae suggests that this is behavioural farming of a chemically defended sponge by a bivalve which does not sequester or synthesize de novo metabolites. Some of the observed benefits of this symbiosis are the enhanced survival of the bivalve, and the sponge being able to live in a site free of competitors. This mutual symbiosis is optional for the sponge but essential for the bivalve, since the fouled bivalves can use the secondary metabolites produced by the sponge to deter predators. We tested the effects of sponge epibiosis on predator preferences. Feeding trials were carried out on the starfish Marthasterias glacialis and the snail Hexaplex trunculus in Hornillo Bay, SE Spain. When A. noae fouled by the sponge Crambe crambe were offered to starfish and snails, they survived significantly more than unfouled bivalves. Field studies in the Mar Menor lagoon indicate that the aposymbiotic populations of A. noae have disappeared from this hypersaline lagoon due to the biological invasion by the non-native snail Hexaplex trunculus. This symbiotic relationship was also effective against octopus. Aposymbiotic bivalves were rapidly eaten when presented to octopuses, while fouled bivalves were consistently rejected.

The rocky littoral is a highly stressed but species rich environment in which adaptive trade-offs underlie the specialization that permits habitat partitioning by closely-related species. Habitat partitioning by prey species is generally attributed to differential tolerances to physiological stresses and competition for resources. Partitioning by predators is, however, less understood and also mainly related to thermal tolerance. We test the hypothesis that differential biomechanical and behavioral adaptations to wave action can result in habitat partitioning of mobile predators using 2 Mediterranean whelks. Stramonita haemastoma is found mainly at wave-exposed habitats on lower midlittoral or shallow (1 to 3 m) subtidal rocks. By contrast, Hexaplex trunculus is found only sub- tidally in more quiescent littoral environments (shallow bays and lagoons or deeper in wave-exposed sites). Morphologically, S. haemastoma is squatter than H. trunculus and the ratio of its foot surface area to the maximum projected surface area of its shell is 35% higher, making S. haemastoma less prone to dislodgment by waves. Mechanically, at least a 2-fold higher force (12 N) is required to dis- lodge S. haemastoma from the substrate, probably due to its larger foot, because tenacity per foot area was similar between species. The feeding technique and foraging behavior of S. haemastoma is also adapted to life in high-energy environments. Higher feeding rates and much shorter prey han- dling time compared to H. trunculus allow this species shorter foraging bouts that reduce the risk of dislodgment and increase predation success in wave-exposed areas. H. trunculus thrives in low-flow habitats where food density is low compared to shallow subtidal rocks. This is compensated for by a broader diet than S. haemastoma, feeding on any available food item, including conspecifics, and by reducing adhesion when not feeding, thus saving energy. S. haemastoma is more adapted to survive desiccation conditions than H. trunculus, which may exclude the latter from intertidal habitats. Our findings suggest that habitat partitioning between the whelks is maintained mainly by a 'distinct preferences' mechanism that might be relevant for other benthic predatory species.

This study aims first to identify nutritionals values of edible mix Muscle Hypobranchial Gland MHG, fresh and cooked extract from internal organs of two gastropods mollusks Hexaplex trunculus HT and Bolinus brandaris BB males and females. Second, to characterize and evaluate the role of hypobranchial glands extract HBGE of these mollusks gastropods on adhesion and cell proliferation of human glioblastoma tumor cells U87. Biochemical analyzes show that fresh MHG, HT and BB are rich in Water 82.52% in HT males, 79.23% in HT females. They are rich in Proteins 12.79 % in BB females to 10.30% in HT females) and in Energy value 79.14 kcal in BB females to 69.48kcal in HT males. They contain fewer carbohydrates 6.27% in BB males to 5.40% in HT males, less total ash 1.52% in HT females to 1.11% in HT males and less lipids 2.55% in HT females to 0.74% in BB males. Further, HBGE of HT inhibited U87 cell adhesion to fibrinogen at 15 mg/ml. This inhibition was accelerated at 20 mg/ml without exceeding 50% of inhibition. HBGE of BB reduced glioblastoma cells adhesion upon to 5 mg/ml with IC50 values of 9 mg/ml for male and 20 mg/ml for female. U87 cells treated with HBGE HT and BB decreased significantly cell proliferation by 50% and 70% respectively. Our results lead us to encourage the use of these marine snails, source of protein and high energy values. Moreover, HBGE may have the potential to serve as a template for future anticancer-drug development. Keywords : Mix Muscle- Hypobranchial Gland, Hexaplex Trunculus, Bolinus Brandaris, Nutritional Values, Glioblastoma U87 Cells, Cell Adhesion and Proliferation.

There is concern that the use of natural volcanic CO2 vents as analogs for studies of the impacts of ocean acidification on marine organisms are biased due to physiochemical influences other than seawater pH alone. One issue that has been raised is whether potentially harmful trace elements in sediments that are rendered more soluble and labile in low pH environments are made more bioavailable, and sequestered in the local flora and fauna at harmful levels. In order to evaluate this hypothesis, we analyzed the concentrations of trace elements in shells (an established proxy for tissues) of four species of gastropods (two limpets, a topshell and a whelk) collected from three sites in Levante Bay, Vulcano Island. Each sampling site increased in distance from the primary CO2 vent and thus represented low, moderate, and ambient seawater pH conditions. Concentrations of As, Cd, Co, Cr, Hg, Mo, Ni, Pb, and V measured in shells using ICP-OES were below detection thresholds for all four gastropod species at all three sites. However, there were measurable concentrations of Sr, Mn, and U in the shells of the limpets Patella caerulea, P. rustica, and the snail Osilinus turbinatus, and similarly, Sr, Mn, U, and also Zn in the shells of the whelk Hexaplex trunculus. Levels of these elements were within the ranges measured in gastropod shells in non-polluted environments, and with the exception of U in the shells of P. caerulea, where the concentration was significantly lower at the collecting site closest to the vent (low pH site), there were no site-specific spatial differences in concentrations for any of the trace elements in shells. Thus trace element enhancement in sediments in low-pH environments was not reflected in greater bioaccumulations of potentially harmful elements in the shells of common gastropods.