Patterns of association among female Indo-Pacific bottlenose dolphins (Tursiops aduncus) in a population forming large groups

Behaviour ◽  
2017 ◽  
Vol 154 (9-10) ◽  
pp. 1013-1028 ◽  
Author(s):  
Miki Nishita ◽  
Miki Shirakihara ◽  
Masao Amano
Keyword(s):  
Group Size ◽  
Bottlenose Dolphins ◽  
Reproductive Status ◽  
Association Measure ◽  
Remarkable Feature ◽  
Tursiops Aduncus ◽  
Large Group ◽  
Photo Identification ◽  
Factors Influencing ◽  
Large Groups

Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Amakusa-Shimoshima, Japan form large groups of >100 individuals, a remarkable feature of this population, which is much larger than previously studied bottlenose dolphins. Using photo-identification data collected on 33 days in 2012, associations among 70 females were investigated using two scales of association measure (photograph- and group-based association) to know whether they associate based on their reproductive status, as is typically observed in other populations with smaller group size. Significant differences in associations between females of the same reproductive status category and those in different categories were detected, and a female that lost her calf within a year decreased associations with females with calves of the same age. These suggests that even in a population with large group size, the reproductive status of females is one of the factors influencing their associations.

Group Characteristics, Site Fidelity And Seasonal Abundance Of Bottlenosed Dolphins (Tursiops Aduncus) In Jervis Bay And Port Stephens, South-Eastern Australia

2002 ◽  
Vol 24 (1) ◽  
pp. 11 ◽  
Author(s):  
LM Möller ◽  
SJ Allen ◽  
RG Harcourt
Keyword(s):  
Group Size ◽  
Site Fidelity ◽  
Human Impacts ◽  
Bottlenose Dolphins ◽  
Seasonal Abundance ◽  
Tursiops Aduncus ◽  
Photo Identification ◽  
Eastern Australia ◽  
Group Characteristics ◽  
Port Stephens

Social organisation and abundance of bottlenose dolphins (Tursiops aduncus) in Jervis Bay (JB) and Port Stephens (PS), NSW, were investigated through behavioural/photo-identification surveys between May 1997 and April 2000. Mean group size was significantly larger at JB (12.3 � 0.87, n =167) compared to PS (6.8 � 0.37, n = 218). At both sites, groups were significantly larger when calves were present. Group size varied with activity, being smallest when feeding and largest when socialising. While mean group size of feeding dolphins did not vary between sites, travelling and socialising groups were significantly larger in JB. Site fidelity was assigned based on sighting rates and presence across seasons. Sighting rates varied significantly between areas, but the proportion of dolphins categorised as residents, occasional visitors and transients did not. Minimum abundance by season, based on mark-resighting of recognisable individuals, ranged from 61 � 3.2 to 108 � 7.1 in JB and 143 � 8.1 to 160 � 8.1 in PS. Differences in group size at the two sites may relate to social factors and/or human impacts, while differences in abundance may be associated with habitat size and complexity. The lack of dolphin matches between areas suggests that they represent distinct populations.

scholarly journals Estimates of abundance and change in abundance of the Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa

2019 ◽  
Author(s):  
OA Vargas-Fonseca ◽  
SP Kirkman ◽  
WC Oosthuizen ◽  
T Bouveroux ◽  
V Cockcroft ◽  
...  
Keyword(s):  
South Africa ◽  
Conservation Status ◽  
Bottlenose Dolphins ◽  
South Coast ◽  
The South ◽  
Model Estimate ◽  
Entire Study ◽  
Tursiops Aduncus ◽  
Photo Identification ◽  
Open Population

AbstractWe investigated the abundance of Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa, from the Goukamma Marine Protected Area (MPA) to the Tsitsikamma MPA, between 2014 and 2016. During this period, 662.3h of boat-based photo-identification survey effort was carried out, and the sighting histories of 817 identified individuals were used to estimate abundance using mark-recapture modelling. The selected open population model (POPAN) provided an estimate of 2,295 individuals (95% CI: 1,157-4,553) for the entire study area. A model estimate was produced for a subset of the study area, Plettenberg Bay, which could be compared with a past estimate for this location (2002-2003). The comparison suggested a 72.3% decrease in abundance, from 6,997 (95% CI: 5,230-9,492) in 2002-2003 to 1,940 (95% CI: 1,448-2,600) in 2014-2016. The decline in abundance was supported by a 72% reduction in mean group size for Plettenberg Bay between the periods. It is essential to be able to assess abundance changes at other locations to inform revision of T. aduncus conservation status in South Africa.

Large group size yields group stability in the cooperatively breeding cichlid Neolamprologus pulcher

Behaviour ◽  
2005 ◽  
Vol 142 (11-12) ◽  
pp. 1615-1641 ◽  
Author(s):  
Michael Taborsky ◽  
Lyanne Brouwer ◽  
Dik Heg ◽  
Zina Bachar
Keyword(s):  
Group Size ◽  
The Body ◽  
Female Size ◽  
Neolamprologus Pulcher ◽  
Large Group ◽  
Cooperatively Breeding ◽  
Group Members ◽  
One Year ◽  
Large Groups

AbstractGroup size has been shown to positively influence survival of group members in many cooperatively breeding vertebrates, including the Lake Tanganyika cichlid Neolamprologus pulcher, suggesting Allee effects. However, long-term data are scarce to test how these survival differences translate into changes in group extinction risk, group size and composition. We show in a field study of 117 groups from six different colonies (three from two populations each), that group size critically influences these parameters between years. Within one year, 34% of the groups went extinct. Group size correlated positively between years and large groups did not go extinct. The latter were more likely to contain small helpers the subsequent year, which is a cumulative measure of the previous months' reproductive success. Finally, there was a tendency that large groups were more likely to contain a breeding male and female still a year after the first check. The breeder male size, breeder female size, and largest helper size did not influence these parameters, and also did not correlate with the sizes of these categories of fish after one year. This suggests that group size, and not the body size or fighting ability of group members, was the critical variable determining the success of groups. In total, seven groups had fused with other groups between years. To our knowledge, this is the first study showing long-term benefits of large group size in a cooperatively breeding fish. We discuss the importance of differential survival and dispersal of group members for the demonstrated group size effects.

An ecological basis for large group size in Colobus angolensis in the Nyungwe Forest, Rwanda

2001 ◽  
Vol 39 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Cheryl Fimbel ◽  
Amy Vedder ◽  
Ellen Dierenfeld ◽  
Felix Mulindahabi
Keyword(s):  
Group Size ◽  
Large Group ◽  
Colobus Angolensis ◽  
Ecological Basis

Pengembangan Bahan Ajar Matematika Bisnis Berbasis Komputer Untuk Mahasiswa Jurusan Akuntansi Politeknik Negeri Bali

Epigram ◽  
2019 ◽  
Vol 16 (2) ◽  
pp. 99-110
Author(s):  
I Made Wijana ◽  
Anak Agung Putri Suardani ◽  
I Gede Made Karma
Keyword(s):  
Small Group ◽  
Mathematics Teaching ◽  
Needs Analysis ◽  
Average Score ◽  
Teaching Materials ◽  
Initial Product ◽  
Large Group ◽  
Computer Based ◽  
Large Groups ◽  
Expert Validation

This research aims to produce prototype of computer-based business mathematics teaching materials to improve student achievement of Accounting Department, Politeknik Negeri Bali (PNB). In this research, to reach the target of teaching materials of computer-based business mathematics, the development using Borg and Gall method with some modifications into five steps: needs analysis and curriculum majoring in accounting, initial product development, education expert validation, small group trial , and large group trials. Trial of small group and large group by involving first semester student of Diploma IV Managerial Accounting Study Program, Accounting Department, PNB. Based on curriculum analysis and needs analysis, teaching materials are developed in the form of modules with Microsoft Excel application and the result of the initial product are five modules with topics of Formula, Linear and Non Linear Functions, Interest Calculation, Annuity, and Linear Programming. Education expert validation using five aspects resulted in an average score of 4.13 (good). Trial of the teaching materials by measuring student perceptions using three aspects for small groups resulted in an average score of 3.81 (good) and for large groups resulted in an average score of 4.23 (good). Furthermore, results of evaluation in large groups indicate a significant increase in mean of student scores from before and after using computer-based Business Mathematics teaching materials 

Reduced Detection of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in an Inner Harbour Channel During Pile Driving Activities

2015 ◽  
Vol 41 (4) ◽  
pp. 455-468 ◽  
Author(s):  
Estênio G. Paiva ◽  
Chandra P. Salgado Kent ◽  
Marthe Monique Gagnon ◽  
Robert McCauley ◽  
Hugh Finn
Keyword(s):  
Bottlenose Dolphins ◽  
Pile Driving ◽  
Tursiops Aduncus

Pregnancy Cravings: Visitation at a Food-Provisioning Site is Driven by the Reproductive Status of Bottlenose Dolphins

2020 ◽  
Vol 15 (3) ◽  
pp. 237-248
Author(s):  
Valeria Senigaglia ◽  
Lars Bejder
Keyword(s):  
Prey Availability ◽  
Southern Oscillation ◽  
Bottlenose Dolphins ◽  
Reproductive Status ◽  
Food Provisioning ◽  
Human Interactions ◽  
Increase Risk ◽  
Lactating Females ◽  
Tourism Attractions ◽  
Marine Wildlife

Marine wildlife tourism attractions often use food rewards to ensure close-up encounters with freeranging animals. In Bunbury, Western Australia, the Dolphin Discovery Centre (DDC) conducts a foodprovision program where bottlenose dolphins (N = 22; between 2000 and 2018) are offered food rewards to encourage their visitation at a beach in front of the DDC. We used historical records on individual beach visits by adult female dolphins collected by the DDC from 2000 to 2018 to develop generalized mixed effects models (GLMM) to test whether the frequency of beach visitation was influenced by their reproductive status (pregnant, lactating, nonreproductive) or climatic events (El Niño-Southern Oscillation phases) that could affect prey availability. We also quantified the behavioral budget of dolphins during food-provisioning sessions and documented intra- and interspecific aggressive behaviors using individual focal follows collected in 2017–2018. Provisioned females spend most of the time resting within the interaction area (66.3%) and aggressive interactions arise as a consequence of dominance behavior over food access. Visitation rates were most influenced by reproductive status with pregnant and lactating females visiting the provisioning area more frequently (z = 2.085, p = 0.037 and z = 2.437, p = 0.014, respectively). Females that frequently visit the provisioning area expose their dependent calves to regular human interactions at an early age when they are more susceptible to behavioral conditioning. Such experiences could cause the loss of awareness towards humans and promote maladaptive behaviors such as begging that increase risk of entanglement in fishing gear, boat strikes, and propeller injuries.

Sign in / Sign up

Export Citation Format

Share Document