New record of the great white shark Carcharodon carcharias from Lampedusa

This new record confirms that the Central Mediter ranean, and Sicilian coasts in particular, still represent a key area for the population of Mediterranean white sharks, but also for other shark species (Bilecenoglu et al., 2013); in fact, 43% of all white shark sightings in the Italian seas (Micarelli et al., 2011) are from this area

Husbandry of Anthias anthias under natural conditions

The fairy basslet (Anthias anthias) is a fis, with a gregary behaviour, that is found commonly at depths from 30m to 200malong the continental shelf and in caves with coralline seabed. Fifty Anthias specimens were collected by scuba divers and transferred to the Argentario Aquarium (Italy), where a special tank was prepared to host them. The anthias spent 3 days in an acclimation containerat different depths before returning to the surface. The present paper disusses the data concerning the first 24 months of their husbandry under natural conditions

The neurohormonal induction of the release of oocytes and sperm from Pecten maximus

In order to induce in vitro maturation of Pecten maximus oocytes, experiments were carried out using different concentrations of the serotonin and dopamine agonists TFMPP, 8-OHDPAT, quinpirole and bromocriptine. The greatest germinal vesicle breakdown (GVBD) occurred using TFMPP. Metaphasic blocks were rarely observed. Oocytes treated with TFMPP at 10 super(-3) and 5x10 super(-4) M could be fertilized at low levels. The maximum fertilization rate recorded was 23%. A second series of experiments was conducted to determine the effects of serotonin, dopamine, the agonists cited above and PGE sub(2) on the release of oocytes and sperm from P. maximus. These inducers were injected into both the male and female parts of the gonads and spermiation was systematically tested approximately 20 minutes following injection. No oocyte release was recorded, except after one injection of 8-OHDPAT at 5x10 super(-4) M; the effect of 8-OHDPAT on the release of oocytes was nevertheless insignificant

Preliminary observations on behaviour and prey items of the whale shark Rhincodon typus in a juvenile aggregation site (Nosy Be, Madagascar)

Rhincodon typus, commonly known as whale shark, is currently listed by the IUCN in the “Endangered” category; it’s believed to feed primarily on meso- and macrozooplankton and has been reported to gather seasonally at a few, well known, coastal regions where has been fuelling a growing tourism industry (Rowat & Brooks, 2012). However, legislation to regulate the interaction between tourists and the foraging sharks is lacking. Well known threats affect the survival of this species, but many aspects of its ecology are still unknown: a deeper knowledge of R. typus feeding ecology is required to better manage interactions at these sites and guarantee a sustainable exploitation of the specie

Influence of Male Presence on the Socıal Structure of Lesser Spotted Dogfısh (Scyliorhinus canicula) Female Groups

Sexual segregation in the lesser spotted dogfish (Scyliorhinus canicula) is most likely driven by the female strategy of avoidance of the males, which causes the formation of female groups in the nooks and shelters on the seafloor. This strategy allows them to reduce the multiple events of male sexual advances, which are energetically expensive. In order to examine the existence of a social structure in female lesser spotted dogfish aggregations and the impact of the presence of males on them, we analyzed the structure of the social network and the temporal stability of the associations of two populations each one including five females. An easy insertion of the males in female population was made possible by the presence of a homogeneous initial social structure with quite weak bonds. The social structure is regulated by differences in the individual behaviour, resulting in different strength and stability of aggregations of conspecifics. The addition of the males produced a reduction of the Average Association Index and of the measures related to the populations’ network, strength of the associations and level of indirect connections of the individual. The presence of the males seems to have a greater effect on the individuals that are more weakly linked; while key individuals typically reduce their network values, but remain well integrated in the population; peripheral individuals have more variables values. This result indicates that relations exist between the sex, which is in contrast with the hypothesis of the female avoidance of males, which should produce strong and stable female groups. The actual knowledge of the behaviour and distribution of the Mediterranean lesser spotted dogfish does not prove the existence of a sexual segregation in this species. Based on the results we can assume that the home-ranges of females and males are not separated and that the male presence does not trigger a female aggregation mechanism. It is noteworthy that males have a destructive effect on the female associations, as these ones have shown a reduction of all the values. This might suggest that, in nature, the male presence and therefore the potential male sexual coercion may cause the spatial dispersion of the individuals of the population and reduce the cohesion of the group

Preliminary Observations on the Ability to Adapt To Salinity Changes in Nursehound Scyliorhinus Stellaris (Linnaeus, 1758) and Small Spotted Catsharks Scyliorhinus Canicula

Nursehound Scyliorhinus stellaris and small spotted catsharks Scyliorhinus canicula are frequently hosted in public aquaria and their husbandry is improving. The reproduction of this species in captive conditions is not difficult and juveniles are easily maintained in laboratory or in thematic tanks showed to the public. Data on juveniles are easily acquired in order to understand different aspects of their natural life and physiology. In two stages, during 2006 and 2010, six S. stellaris and three S. canicula juveniles were tested at different salinity levels under controlled conditions in order to understand their responses in terms of respiration rate to this stress. In fact this is a benthic species living at constant water quality parameters at approximately 70-100 meters deep

Passive Prey Discrimination in Surface Predatory Behaviour of Bait-Attracted White Sharks from Gansbaai, South Africa

5noopenBetween the years 2008 and 2013, six annual research expeditions were carried out at Dyer Island (Gansbaai, South Africa) to study the surface behaviour of white sharks in the presence of two passive prey: tuna bait and a seal-shaped decoy. Sightings were performed from a commercial cage-diving boat over 247 h; 250 different white sharks, with a mean total length (TL) of 308 cm, were observed. Of these, 166 performed at least one or more interactions, for a total of 240 interactions with bait and the seal-shaped decoy. In Gansbaai, there is a population of transient white sharks consisting mainly of immature specimens throughout the year. Both mature and immature sharks preferred to prey on the seal-shaped decoy, probably due to the dietary shift that occurs in white sharks whose TL varies between 200 cm and 340 cm. As it is widely confirmed that white sharks change their diet from a predominantly piscivorous juvenile diet to a mature marine mammalian diet, it is possible that Gansbaai may be a hunting training area and that sharks show a discriminate food choice, a strategy that was adopted by the majority of specimens thanks to their ability to visualize energetically richer prey, after having been attracted by the odorous source represented by the tuna bait.openMicarelli, Primo; Chieppa, Federico; Pacifico, Antonio; Rabboni, Enrico; Reinero, Francesca RomanaMicarelli, Primo; Chieppa, Federico; Pacifico, Antonio; Rabboni, Enrico; Reinero, Francesca Roman

Preliminary observations about white shark's (Carcharodon carcharias) discriminatory patterns during surface predatory activity and type of approach

The aim of the present study was to gather information on the behaviour of great white shark Carcharodon carcharias during surface predatory activities. According to the present results, vision plays an important role in feeding patterns and appears correlated to weather conditions

Induction de la ponte chez la coquille Saint Jacques: utilisation des neuromediateurs

Les gamètes de coquille St-Jacques sont récoltés de manière empirique dans les éc/oseries. Les produits sont obtenus dans des délais variables, en quantité et en qualité imprévisibles. L'effet des neuromédiateurs en tant que régulateurs potentiels du phénomène d'émission des gamètes, communément appelé ponte, a été testé. La sérotonine s'est avérée être un excellent régulateur de la spermiation. Un protocole de collecte du sperme a été établi. En revanche l'obtention des ovocytes s'est révélée plus délicate. Elle est possible, mais un protocole standard n 'a pu être défini