Group size and feeding success in strand-feeding bottlenose dolphins (Tursiops truncatus) in Bull Creek, South Carolina

2015 ◽  
Vol 31 (3) ◽  
pp. 1252-1257 ◽  
Author(s):  
Teresa J. Gisburne ◽  
Richard C. Connor
Keyword(s):  
South Carolina ◽  
Group Size ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Feeding Success ◽  
Bull Creek

Influence of artisanal fisheries on the behaviour and social structure of Tursiops truncatus in the South-western Gulf of Mexico

2019 ◽  
Vol 99 (8) ◽  
pp. 1841-1849
Author(s):  
Nataly Morales-Rincon ◽  
Eduardo Morteo ◽  
Christian Alejandro Delfín-Alfonso
Keyword(s):  
Gulf Of Mexico ◽  
Group Size ◽  
Age Structure ◽  
Human Activities ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Vantage Point ◽  
Competitive Interactions ◽  
Artisanal Fisheries ◽  
Behavioural Plasticity

AbstractBehavioural plasticity in animals is tested whenever competitive interactions for space and/or food resources occur between wildlife and human activities. This study uses the concepts of operational and non-operational interactions between bottlenose dolphins (Tursiops truncatus) and artisanal fisheries in Alvarado, to search for differences in behaviour, age structure and group size. We conducted 20 surveys between 2015 and 2016, and recorded 64 groups by means of scan sampling from either a research boat or a fixed vantage point. Average dolphin group size was small (${\bar{\rm x}}$ = 3.2, SD = 2.2 individuals) and fewer individuals were commonly present when interaction with fisheries occurred. Operational interactions were defined within the first 30 m and occurred mainly with lone individuals (54% recorded from the lighthouse and 82% during surveys); this benchmark also accounted for higher frequencies in locomotion and feeding (χ2 = 83.10; df = 7; P < 0.001). We found a higher rate of new behavioural events for dolphin groups furthest from human activities, as well as a decrease in behaviours that imply greater body exposure as dolphins approach the fishing spots. Age structure and dolphin group size were not different during and in the absence of interaction with fisheries, but most interactions involved male dolphins. Behavioural variations in the dolphins' repertoire are likely a strategy to reduce the risk of injuries or death when interacting with human activities; these dolphins seem to have habituated to or at least tolerate fishing activities within the study area, possibly constituting a sex-biased pressure.

scholarly journals Occurrence of Brucella ceti in stranded bottlenose dolphins Tursiops truncatus coincides with calving season

2020 ◽  
Vol 141 ◽  
pp. 185-193
Author(s):  
WE McFee ◽  
D Wu ◽  
K Colegrove ◽  
K Terio ◽  
L Balthis ◽  
...  
Keyword(s):  
South Carolina ◽  
Tursiops Truncatus ◽  
Marine Mammals ◽  
Marine Bacterium ◽  
Bottlenose Dolphins ◽  
Global Public Health ◽  
Terrestrial Species ◽  
Long Term Study ◽  
Calving Season

Brucellosis is a disease caused by the Gram-negative facultative intracellular bacterium Brucella spp. In terrestrial species, this zoonotic bacterium is a global public health risk, but there is also concern over the zoonotic potential of marine forms, such as B. ceti, which affects cetaceans. Due to the detection of B. ceti in samples from bottlenose dolphins Tursiops truncatus during the 2010-2014 Gulf of Mexico Unusual Mortality Event, a long-term study of the prevalence of Brucella in stranded bottlenose dolphins from South Carolina, USA, was conducted. From 2012 through 2017, 282 stranded bottlenose dolphins were tested for B. ceti via real-time PCR. Nearly 32% of the dolphins tested positive in at least one sample (brain, lung, blowhole swab). Very little information exists in the literature on the occurrence of Brucella spp. in marine mammals, though in terrestrial species, such as cattle and elk, higher prevalence is often reported in spring. Similar results were found in this study with the peak occurrence being between March and June, a known period of calving in South Carolina. Results from this study provide important insights into the occurrence of the marine bacterium B. ceti.

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