Shark Research Institute

Princeton, NJ, United States

Shark Research Institute

Princeton, NJ, United States
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Ritter E.K.,Shark Research Institute | Compagno L.J.V.,Stellenbosch University
Marine Biodiversity Records | Year: 2013

A video clip from the Galápagos Archipelago confirms the first recording of the smalltooth sandtiger shark, Odontaspis ferox, in these islands. Further sightings of this species in the eastern Pacific will likely follow, considering that other, relatively nearby islands lay within reach of the Equatorial Counter Current and North Equatorial Current, which connect some already reported sightings. © Marine Biological Association of the United Kingdom 2013.


Unger N.R.,Nova Southeastern University | Ritter E.,University of West Florida | Ritter E.,Shark Research Institute | Borrego R.,St Marys Medical Center | And 2 more authors.
PLoS ONE | Year: 2014

Sharks possess a variety of pathogenic bacteria in their oral cavity that may potentially be transferred into humans during a bite. The aim of the presented study focused on the identification of the bacteria present in the mouths of live blacktip sharks, Carcharhinus limbatus, and the extent that these bacteria possess multi-drug resistance. Swabs were taken from the oral cavity of nineteen live blacktip sharks, which were subsequently released. The average fork length was 146 cm (±11), suggesting the blacktip sharks were mature adults at least 8 years old. All swabs underwent standard microbiological work-up with identification of organisms and reporting of antibiotic susceptibilities using an automated microbiology system. The oral samples revealed an average of 2.72 (±1.4) bacterial isolates per shark. Gram-negative bacteria, making up 61% of all bacterial isolates, were significantly (p<0.001) more common than gram-positive bacteria (39%). The most common organisms were Vibrio spp. (28%), various coagulase-negative Staphylococcus spp. (16%), and Pasteurella spp. (12%). The overall resistance rate was 12% for all antibiotics tested with nearly 43% of bacteria resistant to at least one antibiotic. Multi-drug resistance was seen in 4% of bacteria. No association between shark gender or fork length with bacterial density or antibiotic resistance was observed. Antibiotics with the highest overall susceptibility rates included fluoroquinolones, 3rd generation cephalosporins and sulfamethoxazole/trimethoprim. Recommended empiric antimicrobial therapy for adult blacktip shark bites should encompass either a fluoroquinolone or combination of a 3rd generation cephalosporin plus doxycycline. © 2014 Unger et al.


Schmidt J.V.,University of Illinois at Chicago | Schmidt J.V.,Shark Research Institute | Chen C.-C.,National Taiwan Ocean University | Sheikh S.I.,University of Illinois at Chicago | And 5 more authors.
Endangered Species Research | Year: 2010

A 10.6 m female whale shark Rhincodon typus caught off the coast of eastern Taiwan in 1995 carried 304 embryos that ranged in developmental stage from individuals still in egg cases to hatched and free-swimming near-term animals. This litter established that whale sharks develop by aplacental yolk-sac viviparity, with embryos hatching from eggs within the female. The range of developmental stages in this litter suggested ongoing fertilization over an extended period of time, with embryos of different ages possibly sired by different males. A series of 9 microsatellite markers for R. typus have now been used to investigate paternity in a subset of these embryos. We determined the paternity of 29 embryos representing 10% of the original litter, and spanning most of the range of size and developmental stage of the 304 embryos. All were full siblings sired by the same male, suggesting that this male may have sired the entire litter. Probability analysis indicates that a second male could go undetected if it sired less than 10% of the litter. The range of developmental stages of embryos from this single sire further suggests that female whale sharks may have the ability to store sperm for later fertilization. In the absence of any tissue to determine parental genotypes, maternal mitochondrial sequence was obtained from the embryos, identifying a novel haplotype linked to those from the western Indian Ocean. This finding adds further support for the global population structure emerging for R. typus. © Inter-Research 2010.


Ritter E.,University of West Florida | Ritter E.,Shark Research Institute | Quester A.,University of Vienna
Journal of Marine Biology | Year: 2016

The theory of mistaken identity states that sharks, especially white sharks, Carcharodon carcharias, mistake surfers for pinnipeds when looking at them from below and thus bite them erroneously. Photographs of surfer wounds and board damage were interpreted with special emphasis on shark size, wound severity, and extent of damage to a board. These were compared with the concurrent literature on attack strategies of white sharks on pinnipeds and their outcomes. The results show that the majority of damage to surfers and their boards is at best superficial-to-moderate in nature and does not reflect the level of damage needed to immobilize or stun a pinniped. It is further shown that the size distribution of sharks biting surfers differs from that in pinnipeds. The results presented show that the theory of mistaken identity, where white sharks erroneously mistake surfers for pinnipeds, does not hold true and should be rejected. © 2016 Erich Ritter and Alexandra Quester.


Ritter E.K.,Shark Research Institute | Amin R.,University of West Florida
Animal Cognition | Year: 2014

The present study examines the potential capability of Caribbean reef sharks to perceive human body orientation, as well as discussing the sharks' swimming patterns in a person's vicinity. A standardized video method was used to record the scenario of single SCUBA divers kneeling in the sand and the approach patterns of sharks, combined with a control group of two divers kneeling back-to-back. When approaching a single test-subject, significantly more sharks preferred to swim outside the person's field of vision. The results suggest that these sharks are able to identify human body orientation, but the mechanisms used and factors affecting nearest distance of approach remain unclear. © 2013 Springer-Verlag Berlin Heidelberg.


Amin R.,University of West Florida | Ritter E.,University of West Florida | Ritter E.,Shark Research Institute | Wetzel A.,University of West Florida
Journal of Coastal Research | Year: 2015

A spatiotemporal cluster analysis of shark-attack rates is applied to identify coastal areas with shark-attack rates that are very high or very low along the North and South Carolina coast. Using a cluster analysis makes it possible to not just pinpoint these areas with more accuracy but also identify where incidents are unlikely to happen. In the past, shark attacks have been studied from a viewpoint of encounter number per region and so limited to the areas in which the attacks occurred. A first look is also taken of the potential influences of some anthropogenic, environmental, and meteorological factors for North and South Carolina in comparison with the better-known attack-prone areas along Florida's coast, to quantify potential causes leading to elevated shark-attack rates, or the lack of them. © Coastal Education & Research Foundation 2015.


Ritter E.K.,University of West Florida | Ritter E.K.,Shark Research Institute | Amin R.W.,University of West Florida
Copeia | Year: 2016

The coexistence between sharksuckers and sharks is poorly understood. Here, we studied the symbiotic client-cleaner relationship between Lemon Sharks, Negaprion brevirostris, and sharksuckers, Echeneis naucrates, with a focus on cleaning inside the sharks' mouths. Where observable, cleaning bouts were either initiated by a sharksucker moving along a shark's snout while maintaining body contact or by swimming in a "dance like" manner in front of the shark's eye without contact, until the shark gaped to allow entry. Sharksuckers interacting with sharks were typically in their first year of their life. While being cleaned by sharksuckers, Lemon Sharks were always seen in one of two positions: either lying flat on the sea floor, or propped on their pectoral fins. Cleaning bouts lasted significantly longer when the shark was propped. In bouts where the location of sharksucker activity within the mouth could be determined, cleaning activity exclusively occurred around the teeth of the upper jaws. In more than half of the bouts, the shark terminated the cleaning by spitting out the sharksucker. Overall, Lemon Sharks and sharksuckers show a highly evolved client-cleaner relationship with both able to influence and trigger the other's behavior. © 2016 by the American Society of Ichthyologists and Herpetologists.


PubMed | Shark Research Institute
Type: Journal Article | Journal: Animal cognition | Year: 2014

The present study examines the potential capability of Caribbean reef sharks to perceive human body orientation, as well as discussing the sharks swimming patterns in a persons vicinity. A standardized video method was used to record the scenario of single SCUBA divers kneeling in the sand and the approach patterns of sharks, combined with a control group of two divers kneeling back-to-back. When approaching a single test-subject, significantly more sharks preferred to swim outside the persons field of vision. The results suggest that these sharks are able to identify human body orientation, but the mechanisms used and factors affecting nearest distance of approach remain unclear.


Although chafing-the rubbing of a body on the sea floor-is a common response of sharks to the attachment of irritating sharksuckers (Echeneis spp.), this behavior has not yet been analyzed in detail. I focused on the different forms and functions of chafing, with special emphasis on the use of sand ripples by sharks during chafing. A significant number of the 146 videotaped Caribbean reef sharks, Carcharhinus perezi (Poey, 1876), and blacktip sharks, Carcharhinus limbatus (Müller and Henle, 1839), preferred to chafe against sand ripples with either a parallel or perpendicular swim direction rather than a transverse swim direction. Tailbeat frequencies of the different forms of the chafing behavior were significantly larger than cruising frequencies. Results indicate that successful chafing requires that sharks employ pattern-recognition and body awareness during chafing. © 2011 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.


Amin R.,University of West Florida | Ritter E.,Shark Research Institute | Kennedy P.,University of West Florida
Marine and Freshwater Behaviour and Physiology | Year: 2012

Shark attacks have historically been studied from a viewpoint of encounter number per region and so limited to the areas in which the attacks occurred. In this exploratory modeling study, the goal was to examine whether an area-specific cluster analysis algorithm undertaken with a modern cluster analysis tool (SaTScan™ 9.1.0) could enhance our spatial and spatio-temporal understanding of attack patterns. The data used were from Florida's east coast between 1994 and 2009. The program suggests several high- and low-risk areas for shark attacks. The results are discussed from a quantitative rather than qualitative perspective. © 2012 Copyright Taylor and Francis Group, LLC.

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