• Animal cells and systems
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• v.14 no.3
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• pp.213-219
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• 2010

Bottlenose dolphins (Tursiops sp.) commonly inhabit Korean waters, including the coastal waters of Jeju Island. However, their taxonomic position was unclear because of the validity of this genus. The genus Tursiops has recently been determined to comprise two species: the common bottlenose dolphin (Tursiops truncatus) and the Indo-Pacific bottlenose dolphin (Tursiops aduncus). To confirm the taxonomic position of bottlenose dolphins frequenting the coastal waters of Jeju Island, the external morphology and osteology of specimens from Jeju Island were examined. Photographs of free-swimming individuals were also used for determining external morphological characters. The cranial and meristic measurements fell within the ranges of T. aduncus. Osteological ratios were also consistent with those of T. aduncus. The presence of a prominent ventral spot was observed among some individuals. As a result, the dolphins mainly distributed in the coastal waters of Jeju Island were identified as Indo-Pacific bottlenose dolphins (T. aduncus) in terms of their cranial characters and ventral spotting. We propose a new Korean name, 'Nambang-keun-dol-go-rae'.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.166-171
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• 2008

The feasibility of photo-identification techniques for the bottlenose dolphins from Jeju Island, Korea, and the potential for dolphin watching were simultaneously evaluated in this study. During the sighting survey, a pod of bottlenose dolphins composed of approximately 30 individuals was observed in the southwestern coastal area of Jeju Island. Among 35 suitable photographs, five bottlenose dolphin individuals were identified and cataloged using unique nicks and notches on their dorsal fins. This shows that the Jeju Island dolphins can be individually identified by the nicks and notches on their dorsal fins using photo-identification techniques. Furthermore, the Jeju Island population appears to be suitable for long-term population biology studies using this technique. The potential for dolphin watching around the island would be higher if more information on the seasonal distribution, movement, and residency of this population were obtained.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.1
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• pp.121-126
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• 2008

This study presents the results of basic sighting surveys conducted for dolphin watching from 2004 to 2006 in the northeastern waters of Jeju. The sighting probability of dolphins (bottlenose dolphin, Tursiops truncatus) was 71.9% (82 sightings out of 114 surveys). The dolphin's attractive behaviors observed included leaping, tail or peduncle slapping and surfing. The findings of this study provide useful baseline data for dolphin watching in the northeastern waters of Jeju.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.940-946
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• 2015

The Indo-Pacific bottlenose dolphin Tursiops aduncus commonly inhabits the coastal waters of Jeju Island, Korea. An investigation was conducted using data from vessel sightings and point sightings from land. During 40 days of vessel sighting surveys between 2007 and 2010, a total of 18 dolphin groups were encountered. The overall sighting rate was 0.01 group/n.m. Most Indo-Pacific bottlenose dolphins were sighted within 500 m of the northern coast of Jeju Island during surveys. Also, dolphin groups were observed 47 times during 109 days of shore-based surveys conducted between 2011 and 2015. The results of a dolphin distribution survey conducted in 2011 were generally similar to the results of previous surveys. However, there were no dolphin sightings from 2012 in Hanllim-eup, in the north-western part of the island, where dolphins were sighted frequently until 2011, whereas dolphin observations increased in the southern part of the island. The mean group size was 35.4 (SD=18.08) individuals. The most frequently sighted group size was 36-40 individuals. To conserve resident dolphins off Jeju Island, long term sighting surveys and environmental assessment are required to monitor their distribution patterns.

• Ocean Science Journal
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• v.43 no.4
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• pp.175-182
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• 2008

Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.600-605
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• 2018

The Indo-Pacific bottlenose dolphins Tursiops aduncus are the only cetacean species that can be observed visually on coastal areas of Jeju Island and regarded as one of valuable tour resources. We attempted to figure out location and timing information of the dolphin sightings collected from two major social media, Naver $Caf{\acute{e}}$ and Instagram. 142 of dolphin sighting information were derived from 2,501 dolphin related postings on Naver $Caf{\acute{e}}$ between 2004 to 2017. 292 informative postings also were found on Instagram through hashtag searching. The number of posts about dolphin sighting was not frequent until 2014. Since 13 posts were found in 2014, dramatic increase of the sighting numbers was accelerated as 38 in 2015, 93 in 2016 and 269 in 2017. 195 (45.7%) from coastal area of Daejeong-eup, south-western part of the Island, were posted. The number of dolphin sightings also high from Gujwa-eup(n=50, 11.7%), Hangyeong-myeon (n=49, 11.5%), Seongsan-eup (n=38, 8.9%) and Seogwipo-si (n=34, 8.0%). Our results show that social media data has a high potential to be used as a data source for study of distribution pattern of the dolphins.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.4
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• pp.271-277
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• 2002

This paper was described on the characteristics of bottlenose dolphin (Tursiops truncatus) whistle to develop a warning and attracting acoustic system which can be made friends woith environment and minimized to the fishing pollution from Cetaceans. The experiment for the acoustics of bottlenose dolphin whistle was carried out in dolphin performance hall at Seoul Grand Park during 18th~19th April, 2002. The frequency and the spectrum level of whistle a same pool were revealed 6~10KHz and 85㏈ but those revealed two harmonic waves a 6.7KHz and 21.3KHz for the frequency and 110㏈ and 94㏈ for the spectrum level, respectively, when a dolphin isolated from others. The range of frequency change of whistle was 3.86KHz and continuous time was 0.08 sec. The range of frequency change 10.20 KHz higher as 14.06 KHz and continuous time was 0.11sec longer as 0.19sec when a dolphin isolated from others. By the Mann-Whitney test for the result, there was a significant difference for the range of frequency change and continuous time between normal condition and when a dolphin was isolated from others. The pattern of whistle at the dolphin performance hall was five types and the frequency was getting increased slowly in the range of 5~10KHz at normal condition but there were pattern change of 5~20KHz at the isolated condition. Therefore it is thought that these experiments would be valuable for the development of acoustic system.

• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.142-144
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• 2016

We report a case of Escherichia coli septicemia in a 6-year-old male bottlenose dolphin (Tursiops truncatus). Gross lesions included turbid reddish yellow ascites, fibrous adhesions of rectum and peritoneum, multifocal mucosal ulcers of rectum, and systemic petechiae. Multifocal necrosis with bacterial colonies was observed histologically in mucosal membrane of rectum and anus, and also in caudal mesenteric lymph node, inguinal lymph node, tracheobronchial lymph node, tonsil, spleen, liver, and lung. E. coli was isolated in pure culture from multiple organs including blood, spleen, mesenteric lymph node, liver, lung, and ascites. The E. coli was serotype O25. This case was diagnosed as a septicemia caused by E. coli serotype O25 associated with proctitis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.650-656
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• 2009

Recently, bottlenose dolphins have frequently appeared in coastal waters of the Jeju Islands. To determine whether these individuals belong to one or more pods, the Cetacean Research Institute (CRI) established visual and photo-identification surveys in the Jeju Islands from November 2007 to July 2009. During visual surveys, pods composed of 10 to 80 individuals were sighted mainly in the northeastern and northwestern of Jeju Islands. Eighty-nine individuals were identified and cataloged by photo-identification using natural nicks and notches on their dorsal fins. Thirty-six individuals were identified three times or more, and nine individuals were identified five times during seven surveys. One individual appeared in November 2007, August 2008, October 2008, April 2009, and July 2009. The results of our study confirm that these dolphins represent a coastal resident stock. Futhermore, we will establish dolphin abundance, management, and usage studies using continuous visual and photo-identification surveys.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.239-242
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• 2001