scholarly journals Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias )

2020 ◽  
Vol 10 (11) ◽  
pp. 4990-5000
Author(s):  
Heather D. Bowlby ◽  
A. Jamie F. Gibson
Keyword(s):  
Life History ◽  
White Shark ◽  
Carcharodon Carcharias ◽  
Northwest Atlantic ◽  
Atlantic Population

First observations of white sharks (Carcharodon carcharias) attacking a live humpback whale (Megaptera novaeangliae)

2020 ◽  
Vol 71 (9) ◽  
pp. 1205
Author(s):  
Sasha Dines ◽  
Enrico Gennari
Keyword(s):  
Life History ◽  
Food Web ◽  
Foraging Ecology ◽  
Humpback Whale ◽  
Marine Ecosystems ◽  
White Shark ◽  
Megaptera Novaeangliae ◽  
Large White ◽  
Carcharodon Carcharias ◽  
History Of

To date, white shark (Carcharodon carcharias) feeding events involving large whales have largely been described only in terms of observed scavenging events. Scavenging occurs in all ecosystems and is usually associated with stochastic feeding events. In marine ecosystems, whale carcasses commonly provide these community-wide food web events. Whale carcasses are the single largest source of carrion in marine ecosystems, to the extent that they are thought to constitute an important part of large white shark foraging ecology, shaping many aspects of the life history of the sharks, including adult migrations. However, to date, no part of this white shark feeding event has been described involving a live whale. To the best of our knowledge, here we provide the first published description of white sharks attacking and killing a live humpback whale (Megaptera novaeangliae). The attack displayed novel behaviours, including evidence of the ‘bite and spit’ tactic, rarely described in non-pinniped-related white shark feeding events before and all part of a tactical timeline of an attack that is precise, deliberate and effective.

Spatiotemporal Patterns of White Shark (Carcharodon carcharias) Predation at the South Farallon Islands, California

Copeia ◽  
1992 ◽  
Vol 1992 (3) ◽  
pp. 680 ◽  
Author(s):  
A. Peter Klimley ◽  
Scot D. Anderson ◽  
Peter Pyle ◽  
R. P. Henderson
Keyword(s):  
White Shark ◽  
Spatiotemporal Patterns ◽  
The South ◽  
Carcharodon Carcharias

scholarly journals Variable response to electric shark deterrents in bull sharks, Carcharhinus leucas

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. R. G. Gauthier ◽  
E. Chateauminois ◽  
M. G. Hoarau ◽  
J. Gadenne ◽  
E. Hoarau ◽  
...  
Keyword(s):  
New Caledonia ◽  
White Shark ◽  
Mitigation Measures ◽  
Control Board ◽  
Variable Response ◽  
Carcharodon Carcharias ◽  
Behavioural Changes ◽  
Carcharhinus Leucas ◽  
Bull Shark ◽  
Over Time

Abstract Although relatively rare, human-shark interactions and sharks bites are increasing globally, which has led to the development of various mitigation measures. Electric shark deterrents (ESDs) have, so far, been the most effective personal deterrents, but have only been scientifically tested on one of the species most frequently responsible for shark bites, i.e. white shark (Carcharodon carcharias). We tested the effectiveness of five ESDs (E-Shark Force, NoShark, Rpela v2, Freedom + Surf, Freedom + Surf—Shortboard) on bull sharks, Carcharhinus leucas, over a period of 21 days in September 2019, in New Caledonia. Standardised bait was attached 30 cm below an experimental board that had an active ESD for up to 15 min, or until a bull shark touched the bait or the board. We compared the numbers of baits taken, numbers of passes and reactions around the board, as well as the distance between the sharks and the board among ESDs and against a control board with bait and no active ESD. The Freedom + Surf was the most effective ESD, reducing the amounts of baits taken by 42.3%, while the Rpela v2 and Freedom + Surf—Shortboard also significantly reduced the number of baits taken by 16.5% and 16.2% respectively. Mean distance between sharks and the bait was not affected by the ESDs, but the number of approaches and the proportion of reactions were both significantly higher when the Freedom + Surf was active compared to other ESDs. The effectiveness of all ESDs decreased over time, with the likelihood of the bait being taken increasing and the number of approaches and distance between sharks and the bait decreasing. Our findings show that the ability of ESDs to deter bull shark varies between products, with the Freedom + Surf resulting in the most behavioural changes, followed by the Rpela v2 and Freedom + Surf—Shortboard. However, none of the products tested completely stopped sharks from taking the bait.

scholarly journals Antibiotic sensitivity of bacteria isolated from the oral cavities of live white sharks (Carcharodon carcharias) in South African waters

2019 ◽  
Vol 115 (11/12) ◽  
Author(s):  
Enrico Gennari ◽  
Alison A. Kock ◽  
Malcolm J. Smale ◽  
Alison Towner ◽  
Nasreen Khan ◽  
...  
Keyword(s):  
South Africa ◽  
Antibiotic Resistance ◽  
South African ◽  
Antibiotic Sensitivity ◽  
White Shark ◽  
Shark Species ◽  
Apex Predators ◽  
Carcharodon Carcharias ◽  
Bacterial Microbiota ◽  
Carbapenem Antibiotic

The white shark (Carcharodon carcharias) is responsible for 49% of shark-related injuries in South Africa, yet no information currently exists on the composition or antibiotic resistance of bacteria hosted by these apex predators in South African waters. This study aimed to address this gap by sampling the bacteria present in the oral cavities of 28 live C. carcharias along South Africa’s southern coastline. The antibiotic resistance of the range of microbiota was also assessed using antibiotic disc diffusion tests. A total of 51 strains from at least 20 species of bacteria were isolated from the oral cavities of C. carcharias. Of these strains, the most common bacteria present were Serratia spp., Proteus vulgaris and Vibrio alginolyticus. The overall antibiotic resistance was relatively higher in this study than that reported for bacterial microbiota sampled from other shark species. Results indicate that the combination therapy of imipenem (carbapenem antibiotic) and vancomycin (glycopeptide antibiotic) might be the most parsimonious option to effectively treat infections resulting from white shark bites, particularly in South Africa. It is hoped that, in addition to assisting medical professionals to treat shark bite victims, these findings enhance the understanding of the microbial communities present in large coastal predators and their surrounding environments.

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