Shark bite marks, including striae, sulci and abrasions, in a well-preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4 m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.

No abstract

No abstract

1. The Mediterranean Sea represents an area of elevated risk of extinction for sharks, where data deficiency is a pervasive problem. 2. To compensate for such a paucity of information, this study investigated the use of social media content as a complementary approach to evaluate the distribution and habitat use of the Critically Endangered blue shark Prionace glauca in coastal waters, as well as public perceptions of the sharks. 3. Through social media data mining a total of 146 records, comprising 158 individual blue sharks approaching Italian coastal waters, have been recorded from 2011 to 2020.4. This study revealed that, over the past decade, blue sharks regularly visited Italian coastal habitats for extended periods of time. Differences in the temporal distribution of blue sharks by sex and size appear to be linked to reproductive activity. The higher number of adult females approaching the shore in spring and the increase in young-of-the-year (YOY) sightings in the following months possibly indicate parturition in coastal waters. Spatial analyses also showed that certain Italian coastal areas, such as those in Calabria and Puglia, were preferred coastal habitats for this species. 5. Results also indicate that social media platforms can be considered an evergrowing source of data on wildlife, which can shed light on the occurrence and distribution of endangered shark species in poorly known habitats. Furthermore, social media platforms should be used for awareness campaigns to educate the public, as this study showed that negative reactions to shark encounters remain widespread.

A low-cost and non-invasive survey technique focused on pelagic sharks was evaluated during an ecotourism cruise on two Sudanese reefs, Angarosh and Sha'ab Rumi, in the Southern Red Sea. The research technology was based on a set of small, underwater video recording cameras and a pair of laser pointers. Video footage provided insight into shark biodiversity on the two reefs, detecting five species, Alopias vulpinus, Sphyrna lewini, Triaenodon obesus, Carcharhinus amblyrhynchos and Galeocerdo cuvier, during 15.8 h of video recording. These recordings also provided preliminary information on aggregations of S. lewini. The laser pointers were used to measure the size of sharks, providing seven total length (TL) measurements for S. lewini (N = 2) and C. amblyrhynchos (N = 5), confirming the possibility of easily obtaining size parameters using this tool. These low-cost and user-friendly instruments provide ecotourism divers with an opportunity to become involved in marine research projects.