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Olaya-Ponzone L, Espada Ruíz R, Martín Moreno E, Patón Domínguez D, García-Gómez JC. Effects of vessels on common dolphin activity patterns in a critical area for the species. Conservation implications. MARINE ENVIRONMENTAL RESEARCH 2025; 207:107081. [PMID: 40120423 DOI: 10.1016/j.marenvres.2025.107081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2024] [Revised: 03/04/2025] [Accepted: 03/09/2025] [Indexed: 03/25/2025]
Abstract
Although whale-watching tourism makes it easier for humans to learn about these animals in the wild, interactions with boats can trigger temporary or even permanent behavioural changes in their populations. In this work we studied the potential effect of boats on the welfare of common dolphins, Delphinus delphis, a protected species in the Mediterranean, as well as a female bottlenose dolphin (Billie-Tursiops truncatus) that coexists with them in the bay of Algeciras-Gibraltar (BA-G), Southern Spain and that gave birth to the first known hybrid between both species in the wild. First, the reaction of the animals (Approach, Elusive and Indifference) to the presence of boats was observed. Subsequently, we have classified the sightings into four situations: Control (C) and Impact (I) with Regulated (RS) and Unregulated (US) sightings. In each situation, six behavioural states were distinguished: Feeding (F), Resting (R), Milling (M), Socialising (S), Travelling (T) and Diving (D). It was concluded that the presence of boats and non-compliance with the protocol for approaching cetaceans were the main causes of the behavioural transitions and that they led to an absorbing D state in the Markov chains. The results showed that the feeding and resting behaviours of the dolphins were significantly altered. Possible alteration of these behaviours may have negative effects on the animals. Our results are further evidence of the need to regulate and monitor vessel activities to protect common dolphins in BA-G, a critical area for this species, which still lacks specific conservation plans.
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Affiliation(s)
- L Olaya-Ponzone
- Laboratory of Marine Biology, Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain; Biological Research Department I+D+i at the Seville Aquarium, Spain.
| | - R Espada Ruíz
- Laboratory of Marine Biology, Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain; Ecolocaliza, C/ Gibraltar 183, La Línea de La Concepción, Cádiz, Spain
| | - E Martín Moreno
- Ecolocaliza, C/ Gibraltar 183, La Línea de La Concepción, Cádiz, Spain
| | | | - J C García-Gómez
- Laboratory of Marine Biology, Department of Zoology, Faculty of Biology, University of Seville, Seville, Spain; Biological Research Department I+D+i at the Seville Aquarium, Spain
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Foord CS, Robb K, Nugegoda D. Trace element concentrations in dolphins of south-east Australia; mercury a cause for concern in the region. MARINE POLLUTION BULLETIN 2024; 209:117130. [PMID: 39461174 DOI: 10.1016/j.marpolbul.2024.117130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 10/08/2024] [Accepted: 10/09/2024] [Indexed: 10/29/2024]
Abstract
Concentrations of nine trace elements (As, Cd, Cr, Cu, Hg, Mn, Ni, Se, Zn) in hepatic, renal and epidermal tissues were investigated in three dolphin species (Burrunan dolphin, Tursiops australis; common bottlenose dolphin, T. truncatus; short-beaked common dolphin, Delphinus delphis) within southeast Australia. Elevated hepatic Hg was found in critically endangered Burrunan dolphins (62.5-4990 mg/kg dw) and common bottlenose dolphins (102-1770 mg/kg dw), amongst the highest for the taxa globally, exceeding the short-beaked common dolphins (3.24-370 mg/kg dw), likely due to dietary differences. Hepatic Hg:Se molar ratios exceeded 1 in 60 % of dolphins, suggesting Hg toxicity. Essential trace elements showed little variation across species, but epidermal Se was notably low in Burrunan dolphins. Due to ongoing freshwater skin disease/health concerns, and the importance Se plays in epidermal health, it is recommended that epidermal Se and skin health are further investigated within the Burrunan dolphin.
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Affiliation(s)
- Chantel S Foord
- Ecotoxicology Research Group, School of Science, Royal Melbourne Institute of Technology, Bundoora, VIC 3083, Australia; Marine Mammal Foundation, PO Box 2046, Hampton East, VIC 3188, Australia.
| | - Kate Robb
- Marine Mammal Foundation, PO Box 2046, Hampton East, VIC 3188, Australia
| | - Dayanthi Nugegoda
- Ecotoxicology Research Group, School of Science, Royal Melbourne Institute of Technology, Bundoora, VIC 3083, Australia
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Sumanapala D, Wolf ID. Status and future directions of cetacean watching tourism: A comparative systematic review of Australia and South and East Asia. REGIONAL STUDIES IN MARINE SCIENCE 2024; 77:103645. [DOI: 10.1016/j.rsma.2024.103645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2025]
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Beddoe J, Shimeta J, Klaassen M, Robb K. Population distribution and drivers of habitat use for the Burrunan dolphins, Port Phillip Bay, Australia. Ecol Evol 2024; 14:e11221. [PMID: 38584772 PMCID: PMC10994984 DOI: 10.1002/ece3.11221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/08/2024] [Accepted: 03/20/2024] [Indexed: 04/09/2024] Open
Abstract
Bottlenose dolphin (Tursiops) populations, also described as the Burrunan dolphins, consist of a resident population of approximately 150 individuals in Port Phillip Bay (PPB), Victoria. Previous reports indicate distribution across a small southern region of PPB; however, little is known about their full distribution patterns across the entire PPB region. Here, we investigate the spatiotemporal distribution of the Burrunan dolphins across four zones representative of PPB benthic habitats and bathymetry to gain a better understanding of the potential drivers of the population's habitat use. Port Phillip Bay, Victoria, Australia. One hundred and twenty-nine boat-based surveys were undertaken between March 2015 and August 2021, encompassing 181 sightings. Generalised linear models (GLMs) were used to investigate annual, seasonal and zonal variation. We found no variation in sighting frequencies between years. Austral summer and winter had a significantly higher sighting frequency than autumn. We found that Burrunan dolphins utilise the entire bay, further extending the species range, and show a significantly higher number of sightings in the southern zone than in any other zones. Overlaying dolphin sightings with known oceanographic characteristics within PPB, we found bathymetry and benthic habitats were potential drivers for the Burrunan dolphins distribution and habitat use within the bay, with the dolphins significantly favouring the 5-10 and 10-15 m contour depths. These results show a more widespread distribution across the bay than previously documented. We recommend expansion of the current marine protected areas in the north and south of the bay. This study has increased our understanding of the vital habitat for the Burrunan dolphin populations. By providing evidence-based conservation recommendations, we hope to improve and contribute to future research, conservation management plans and effective marine protected areas across PPB for the resident Burrunan dolphin population.
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Affiliation(s)
- Jemima Beddoe
- School of ScienceRMIT UniversityMelbourneVictoriaAustralia
- Australian Marine Mammal Conservation FoundationHampton EastVictoriaAustralia
| | - Jeff Shimeta
- School of ScienceRMIT UniversityMelbourneVictoriaAustralia
| | - Marcel Klaassen
- School of Life and Environmental SciencesDeakin UniversityGeelongVictoriaAustralia
| | - Kate Robb
- Australian Marine Mammal Conservation FoundationHampton EastVictoriaAustralia
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Lacetera P, Mason SJ, Tixier P, Arnould JPY. Using ecotourism boats for estimating the abundance of a bottlenose dolphin population in south-eastern Australia. PLoS One 2023; 18:e0289592. [PMID: 37540663 PMCID: PMC10403133 DOI: 10.1371/journal.pone.0289592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 07/21/2023] [Indexed: 08/06/2023] Open
Abstract
It is challenging to collect robust, long-term datasets to properly monitor the viability and social structure of large, long-lived animals, especially marine mammals. The present study used a unique long-term dataset to investigate the population parameters and social structure of a poorly studied population of bottlenose dolphins (Tursiops sp.) in southern Port Phillip Bay, south-eastern Australia. Photo-identification images have been collected between 2012-2022 both opportunistically and following a protocol by patrons, staff, and volunteers of ecotourism companies using their vessels as platforms. The resulting large dataset was available to be processed through the online platform Flukebook and used in capture recapture models to estimate abundance and demographic parameters. In addition, the social structure of the population and the reproductive parameters were investigated. The marked adult population abundance (45.2 ± 2.7 individuals) was found to be stable over the last decade and the calving rate ranged between 0.06-0.19 new calves per identified individuals per year, while the inter-birth interval was 3.7 ± 0.8 years. Social analysis suggested the population has a fission-fusion structure with no apparent clusters. The stability of the population over the study period suggests no deleterious effect of anthropogenic or environmental factors during the last decade. This study is the outcome of the effort of the ecotourism organisations and the results obtained, along with their similarity to those of other dolphin populations worldwide, highlight the importance of such data sources for long-term information that would otherwise be too expensive or logistically difficult to obtain.
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Affiliation(s)
- Paola Lacetera
- School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Burwood, Victoria, Australia
- Faculty of Science, Krijgslaan, Gent University, Gent, Belgium
| | - Suzanne J. Mason
- School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Burwood, Victoria, Australia
- Cetacean Science Connections, Forest Hill, Victoria, Australia
| | - Paul Tixier
- MARBEC, Université de Montpellier-CNRS-IFREMER-IRD, Sète, France
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Burwood, Victoria, Australia
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Quintana Martín-Montalvo B, Hoarau L, Deffes O, Delaspre S, Delfour F, Landes AE. Dolphin Watching and Compliance to Guidelines Affect Spinner Dolphins' ( Stenella longirostris) Behaviour in Reunion Island. Animals (Basel) 2021; 11:ani11092674. [PMID: 34573639 PMCID: PMC8470298 DOI: 10.3390/ani11092674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/25/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022] Open
Abstract
Simple Summary Whale and dolphin watching have expanded worldwide, with their impacts on cetaceans over the short and long terms being widely reported. In Reunion Island, the activity has rapidly developed, notably around a resident spinner dolphin population, which can be seen year-round. Focal follows revealed that the dolphins are less likely to begin socialising or resting and more likely to remain travelling or milling in the presence of dolphin-watching vessels. The dolphins’ avoidance reactions increased when tourist vessels were numerous or in non-compliance with the regulations. The cumulative effect of such behavioural responses likely impacts the dolphins at the population level, highlighting the need for enforcing adaptive and efficient dolphin-watching management measures to ensure the welfare and preservation of the resident spinner dolphins of Reunion Island. Abstract Marine wildlife tourism has rapidly developed in Reunion Island, due to a large demand for interactions with a resident population of spinner dolphins (Stenella longirostris). The presence of dolphin-watching vessels close to dolphin groups can cause short-term impacts on their behaviour; cumulative incidences likely result in deleterious long-term impacts on the population. Using scan sampling, we collected behavioural data on spinner dolphins to evaluate the short-term effects of dolphin watching on their behaviour. The dolphins were less likely to begin socialising or diving while travelling and more likely to stay travelling and milling in the presence of vessels. Additionally, activity budgets for resting and socialising decreased simultaneously with increased travelling and milling. Avoidance responses significantly increased with an increase in the number of vessels and non-compliance with the local dolphin-watching guidelines. These behavioural responses are likely to have energetic costs for the dolphins, which may lead to decreased survival and reproductive success at individual and population levels. More restrictive regulations, increased surveillance and animal-based measures are key tools to adapt the conservation efforts in Reunion Island. Further studies on the island’s resident dolphin populations are necessary to ensure the continuity of dolphin-watching activities in a sustainable manner.
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Affiliation(s)
- Belén Quintana Martín-Montalvo
- Centre d’Etude et Découverte des Tortues Marines (CEDTM), 97424 Piton Saint Leu, France; (O.D.); (S.D.); (A.-E.L.)
- Correspondence:
| | - Ludovic Hoarau
- UMR ENTROPIE, Université de La Réunion, IRD, CNRS, IFREMER, UNC, CEDEX 9, 97744 Saint Denis, France;
| | - Ophélie Deffes
- Centre d’Etude et Découverte des Tortues Marines (CEDTM), 97424 Piton Saint Leu, France; (O.D.); (S.D.); (A.-E.L.)
- Faculté des Sciences et Techniques, Université Jean Monnet, 42100 Saint-Etienne, France
| | - Sylvain Delaspre
- Centre d’Etude et Découverte des Tortues Marines (CEDTM), 97424 Piton Saint Leu, France; (O.D.); (S.D.); (A.-E.L.)
| | | | - Anne-Emmanuelle Landes
- Centre d’Etude et Découverte des Tortues Marines (CEDTM), 97424 Piton Saint Leu, France; (O.D.); (S.D.); (A.-E.L.)
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