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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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Longden EG, Gillespie D, Mann DA, McHugh KA, Rycyk AM, Wells RS, Tyack PL. Comparison of the marine soundscape before and during the COVID-19 pandemic in dolphin habitat in Sarasota Bay, FL. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:3170. [PMID: 36586823 DOI: 10.1121/10.0015366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 11/06/2022] [Indexed: 06/17/2023]
Abstract
During the COVID-19 pandemic, changes in vessel activity and associated noise have been reported globally. Sarasota Bay is home to a large and increasing number of recreational vessels as well as a long-term resident community of bottlenose dolphins, Tursiops truncatus. Data were analyzed from two hydrophones to compare the soundscape during the COVID-19 pandemic to previous years (March-May 2020 and 2018/2019). Hourly metrics were calculated: vessel passes, 95th percentile sound levels [125 Hz and 16 kHz third octave bands (TOBs), and two broader bands: 88-1122 Hz and 1781-17 959 Hz], and dolphin whistle detection to understand changes in vessel activity and the effect on wildlife. Vessel activity increased during COVID-19 restrictions by almost 80% at one site and remained the same at the other site. Of the four sound level measures, only the 125 Hz TOB and 88-1122 Hz band increased with vessel activity at both sites, suggesting that these may be appropriate measures of noise from rapid pass-bys of small vessels in very shallow (<10 m) habitats. Dolphin whistle detection decreased during COVID-19 restrictions at one site but remained the same at the site that experienced increased vessel activity. The results suggest that pandemic effects on wildlife should not be viewed as homogeneous globally.
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Affiliation(s)
- E G Longden
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, KY16 8LB, United Kingdom
| | - D Gillespie
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, KY16 8LB, United Kingdom
| | - D A Mann
- Loggerhead Instruments, Inc., Sarasota, Florida 34238, USA
| | - K A McHugh
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, Florida 34236, USA
| | - A M Rycyk
- Division of Natural Sciences, New College of Florida, Sarasota, Florida 34243, USA
| | - R S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, Florida 34236, USA
| | - P L Tyack
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, KY16 8LB, United Kingdom
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Assessment on the effectiveness of vessel-approach regulations to protect cetaceans in Australia: A review on behavioral impacts with case study on the threatened Burrunan dolphin (Tursiops australis). PLoS One 2021; 16:e0243353. [PMID: 33465088 PMCID: PMC7815133 DOI: 10.1371/journal.pone.0243353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 11/19/2020] [Indexed: 12/04/2022] Open
Abstract
Vessels cause considerable disturbance to cetaceans world-wide, with potential long-term impacts to population viability. Here we present a comprehensive review of vessel impacts to cetacean behavior in Australian waters (2003–2015), finding inadequate protections to be in place. The majority of these studies found trends of decreased animal travel and resting behavioral states as well as low compliance to regulations, and they recommended further regulatory action such as greater enforcement or monitoring, or passive management strategies. As a case study, we conducted the first field assessment of vessel compliance with the Wildlife (Marine Mammal) Regulations 2009 in Gippsland Lakes, Australia, and provide the first assessment of the endangered Gippsland Lakes Burrunan dolphin (Tursiops australis) population’s behavioral ecology. Dolphin behavior and vessel regulation compliance data were collected during boat-based surveys of Gippsland Lakes from July 2017 to January 2018, with a total of 22 dolphin group sightings resulting in 477 five-minute point samples. 77% of dolphin sightings involved vessel interactions (within 400 m), and 56 regulation breaches were observed. These breaches were most severe in summer (mean = 4.54 breaches/hour). Vessels were found to alter dolphin behavior before, during, and after interactions and regulation breaches, including increased mating (mate guarding) and milling behavioral states, and increased ‘fish catch’, ‘high leap’ and ‘tail slap’ behavioral events. These behavioral changes may indicate masking of the dolphins' acoustic communication, disturbance of prey, increased dolphin transition behaviors, and/or induced stress and changes to group structure (including increased mate guarding). While our results provide evidence of short-term altered behavior, the potential for long-term effects on population dynamics for this threatened species is high. In the context of reported inadequate cetacean protection Australia-wide, our management recommendations include greater monitoring and enforcement, and the utilisation of adaptive management.
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Marley SA, Salgado Kent CP, Erbe C, Parnum IM. Effects of vessel traffic and underwater noise on the movement, behaviour and vocalisations of bottlenose dolphins in an urbanised estuary. Sci Rep 2017; 7:13437. [PMID: 29044128 PMCID: PMC5647363 DOI: 10.1038/s41598-017-13252-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/21/2017] [Indexed: 11/20/2022] Open
Abstract
The potential disturbance of dolphins from tourism boats has been widely discussed in the literature, in terms of both physical vessel presence and associated underwater noise. However, less attention has been paid to the potential impact of non-tourism vessels, despite these being much more widespread and occurring in greater numbers throughout coastal dolphin habitats. The Indo-Pacific bottlenose dolphin (T. aduncus) community using the Fremantle Inner Harbour, Western Australia, is exposed to high levels of vessel traffic. To investigate whether behavioural responses could be occurring, a non-invasive combination of visual and acoustic monitoring was conducted using a theodolite and an autonomous acoustic logger. Dolphins significantly increased their average movement speeds in high vessel densities, but only for some activity states. Behavioural budgets also changed in the presence of vessels, with animals spending greater time travelling and less time resting or socialising. Finally, multiple whistle characteristics varied with rising levels of broadband noise, and other contextual variables. Despite being acoustically specialised for higher frequencies, dolphins had the strongest acoustic variation during low-frequency noise. This study highlights the complexity of disturbance responses in this species, confirming the need for consideration of both surface and acoustic behaviour alongside appropriate contextual data.
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Affiliation(s)
- Sarah A Marley
- Centre for Marine Science and Technology (CMST), Curtin University, Perth, Western Australia, Australia.
| | - Chandra P Salgado Kent
- Centre for Marine Science and Technology (CMST), Curtin University, Perth, Western Australia, Australia
| | - Christine Erbe
- Centre for Marine Science and Technology (CMST), Curtin University, Perth, Western Australia, Australia
| | - Iain M Parnum
- Centre for Marine Science and Technology (CMST), Curtin University, Perth, Western Australia, Australia
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Filby NE, Christiansen F, Scarpaci C, Stockin KA. Effects of swim-with-dolphin tourism on the behaviour of a threatened species, the Burrunan dolphin Tursiops australis. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00826] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Heiler J, Elwen S, Kriesell H, Gridley T. Changes in bottlenose dolphin whistle parameters related to vessel presence, surface behaviour and group composition. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Temple AJ, Tregenza N, Amir OA, Jiddawi N, Berggren P. Spatial and Temporal Variations in the Occurrence and Foraging Activity of Coastal Dolphins in Menai Bay, Zanzibar, Tanzania. PLoS One 2016; 11:e0148995. [PMID: 26934473 PMCID: PMC4774871 DOI: 10.1371/journal.pone.0148995] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 01/25/2016] [Indexed: 11/21/2022] Open
Abstract
Understanding temporal patterns in distribution, occurrence and behaviour is vital for the effective conservation of cetaceans. This study used cetacean click detectors (C-PODs) to investigate spatial and temporal variation in occurrence and foraging activity of the Indo-Pacific bottlenose (Tursiops aduncus) and Indian Ocean humpback (Sousa plumbea) dolphins resident in the Menai Bay Conservation Area (MBCA), Zanzibar, Tanzania. Occurrence was measured using detection positive minutes. Inter-click intervals were used to identify terminal buzz vocalisations, allowing for analysis of foraging activity. Data were analysed in relation to spatial (location) and temporal (monsoon season, diel phase and tidal phase) variables. Results showed significantly increased occurrence and foraging activity of dolphins in southern areas and during hours of darkness. Higher occurrence at night was not explained by diel variation in echolocation rate and so were considered representative of occurrence patterns. Both tidal phase and monsoon season influenced occurrence but results varied among sites, with no general patterns found. Foraging activity was greatest during hours of darkness, High water and Flood tidal phases. Comparisons of echolocation data among sites suggested differences in the broadband click spectra of MBCA dolphins, possibly indicative of species differences. These dolphin populations are threatened by unsustainable fisheries bycatch and tourism activities. The spatial and temporal patterns identified in this study have implications for future conservation and management actions with regards to these two threats. Further, the results indicate future potential for using passive acoustics to identify and monitor the occurrence of these two species in areas where they co-exist.
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Affiliation(s)
- Andrew J. Temple
- School of Marine Science & Technology, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
| | - Nick Tregenza
- Chelonia Limited, The Barkhouse, North Cliff, Mousehole, Cornwall, United Kingdom
| | - Omar A. Amir
- Ministry of Livestock and Fisheries, Nyangumi House, Maruhubi Street, Zanzibar, Tanzania
| | - Narriman Jiddawi
- Institute of Marine Sciences, Dar es Salaam University, Zanzibar, Tanzania
| | - Per Berggren
- School of Marine Science & Technology, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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Vermeulen E, Bräger S. Demographics of the disappearing bottlenose dolphin in Argentina: a common species on its way out? PLoS One 2015; 10:e0119182. [PMID: 25786234 PMCID: PMC4364992 DOI: 10.1371/journal.pone.0119182] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 01/25/2015] [Indexed: 11/19/2022] Open
Abstract
Populations of the once common bottlenose dolphin (Tursiops truncatus) in Argentina have precipitously declined throughout the country in the past decades. Unfortunately, local declines of common species are easily overlooked when establishing priorities for conservation. In this study, demographics of what may well be the last remaining resident population in the country were assessed using mark-recapture analysis (Pollock's Robust Design) of a photo-identification dataset collected during 2006-2011 in Bahía San Antonio (Patagonia, Argentina). Total abundance, corrected for unmarked individuals, ranged from 40 (95%CI: 16.1-98.8) to 83 (95%CI = 45.8-151.8) individuals and showed a decrease over the years. Adult survival rates varied between 0.97 (± 0.037 SE) and 0.99 (± 0.010 SE). Average calving interval equalled 3.5 ± 1.03 years, with 3.5 births/year in the entire population and a minimum annual birth rate of 4.2%. However, data suggest that calves may have been born and lost before being documented, underestimating birth rate, calf mortality, and possibly the number of reproductive females. Either way, the recruitment rate of calves appears to be insufficient to support the size of the population. This population is relatively small and declining. Considering the disappearance of populations north and south of the study area, an incessant decline will have severe consequences for the continuous existence of this species in Argentina, indicating an urgent need for serious conservation efforts. This study provides insight into how the failure to recognize local population declines can threaten the national (and eventually the international) status of a common species like the bottlenose dolphin.
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Affiliation(s)
- Els Vermeulen
- Laboratory of Oceanology, MARE Research Centre, University of Liège, Liège, Belgium
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Meissner AM, Christiansen F, Martinez E, Pawley MDM, Orams MB, Stockin KA. Behavioural effects of tourism on oceanic common dolphins, Delphinus sp., in New Zealand: the effects of Markov analysis variations and current tour operator compliance with regulations. PLoS One 2015; 10:e0116962. [PMID: 25565523 PMCID: PMC4286237 DOI: 10.1371/journal.pone.0116962] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022] Open
Abstract
Common dolphins, Delphinus sp., are one of the marine mammal species tourism operations in New Zealand focus on. While effects of cetacean-watching activities have previously been examined in coastal regions in New Zealand, this study is the first to investigate effects of commercial tourism and recreational vessels on common dolphins in an open oceanic habitat. Observations from both an independent research vessel and aboard commercial tour vessels operating off the central and east coast Bay of Plenty, North Island, New Zealand were used to assess dolphin behaviour and record the level of compliance by permitted commercial tour operators and private recreational vessels with New Zealand regulations. Dolphin behaviour was assessed using two different approaches to Markov chain analysis in order to examine variation of responses of dolphins to vessels. Results showed that, regardless of the variance in Markov methods, dolphin foraging behaviour was significantly altered by boat interactions. Dolphins spent less time foraging during interactions and took significantly longer to return to foraging once disrupted by vessel presence. This research raises concerns about the potential disruption to feeding, a biologically critical behaviour. This may be particularly important in an open oceanic habitat, where prey resources are typically widely dispersed and unpredictable in abundance. Furthermore, because tourism in this region focuses on common dolphins transiting between adjacent coastal locations, the potential for cumulative effects could exacerbate the local effects demonstrated in this study. While the overall level of compliance by commercial operators was relatively high, non-compliance to the regulations was observed with time restriction, number or speed of vessels interacting with dolphins not being respected. Additionally, prohibited swimming with calves did occur. The effects shown in this study should be carefully considered within conservation management plans, in order to reduce the risk of detrimental effects on common dolphins within the region.
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Affiliation(s)
- Anna M. Meissner
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore City, Auckland, New Zealand
- * E-mail:
| | - Fredrik Christiansen
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Warrnambool Campus, PO Box 423, Warrnambool, Victoria, Australia
- Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, South Street, Western Australia, Australia
| | - Emmanuelle Martinez
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore City, Auckland, New Zealand
- Pacific Whale Foundation, 300 Ma’alaea Rd., Suite 211, Wailuku, Hawaii, United States of America
| | - Matthew D. M. Pawley
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore City, Auckland, New Zealand
| | - Mark B. Orams
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore City, Auckland, New Zealand
- New Zealand Tourism Research Institute, School of Hospitality and Tourism, Auckland University of Technology, Private Bag 92006, Auckland, New Zealand
| | - Karen A. Stockin
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore City, Auckland, New Zealand
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Filby NE, Stockin KA, Scarpaci C. Long-term responses of Burrunan dolphins ( Tursiops australis ) to swim-with dolphin tourism in Port Phillip Bay, Victoria, Australia: A population at risk. Glob Ecol Conserv 2014. [DOI: 10.1016/j.gecco.2014.08.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Guerra M, Dawson SM, Brough TE, Rayment WJ. Effects of boats on the surface and acoustic behaviour of an endangered population of bottlenose dolphins. ENDANGER SPECIES RES 2014. [DOI: 10.3354/esr00598] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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May-Collado LJ, Quiñones-Lebrón SG. Dolphin changes in whistle structure with watercraft activity depends on their behavioral state. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 135:EL193-EL198. [PMID: 25236153 DOI: 10.1121/1.4869255] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dolphins rely on whistles to identify each other and to receive and convey information about their environment. Although capable of adjusting these signals with changing environments, there is little information on how dolphins acoustically respond to different watercraft activities and if this response depends on dolphin behavioral state. Bottlenose dolphin whistles were recorded in the presence of research and dolphin-watching boats. Dolphins emitted lower frequency and longer whistles when interacting with dolphin-watching boats, particularly during foraging activities. This study suggests that dolphin-watching boat traffic significantly hinders dolphin communication during important behavioral states.
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Affiliation(s)
- Laura J May-Collado
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, Vermont 05405
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Schumann N, Gales NJ, Harcourt RG, Arnould JPY. Impacts of climate change on Australian marine mammals. AUST J ZOOL 2013. [DOI: 10.1071/zo12131] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Increasing evidence suggests that climate change is negatively affecting marine ecosystems and biota. However, little is known of how climate change will impact marine mammals. This review aims to identify the effects of climatic variations on Australian marine mammals and determine their potential responses to climate change. Shifts in distributions and reproductive success have been associated with climatic factors, while stranding events, drowning of seal pups, exposure to altered water conditions and disease in several marine mammal species have followed extreme weather events. Climate change may produce distributional shifts as the ranges of warm-water species expand or shift southwards, and those of cold-water species contract. Reductions in the extent of key habitats, changes in breeding success, a greater incidence of strandings in dugongs and cetaceans, and increased exposure of coastal species to pollutants and pathogens are likely. The capacity of Australian marine mammals to adapt to climate change is poorly understood, though there is evidence that several species may be able to modify their physiology or behaviour in response to warming temperatures. To increase the resilience of marine mammals, it is necessary to address non-climatic threats, such as ensuring that key habitats are protected in Australia.
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