Did you know that there are numerous studies on the dolphins that live in the rivers and in WA coastal waters? Check out some of the following papers below.
Entanglement in recreational fishing gear poses a threat to estuarine and coastal dolphins: Animal welfare and population level impacts should guide intervention decision making
Derelict and active fishing gear poses a threat to marine wildlife. This study details Indo-Pacific bottlenose dolphin entanglements in recreational fishing gear in the Peel-Harvey Estuary, Western Australia between 2016 and 2022. Eight entanglements were recorded, three resulted in death. Dolphin calf Luca of the Mandurah population (pictured below) who suffered several entanglements and died as a result of an infection caused by the injuries in 2019 (photos by Estuary Guardians Mandurah).
When we say goodbye – an analysis of Standard Operating Procedures the guide end-of-life decision making for stranded cetaceans in Australia
Standard Operating Procedures (SOPs) are tools used to ensure management best practice during emergency incidents including wildlife interventions, such as cetacean strandings. The compromised state of stranded cetaceans means humane end-of-life decisions may be considered, and SOPs frequently guide this process. This study evaluated SOPs for end-of-life decision-making and technically enacting euthanasia of stranded cetaceans across Australasia.
Evidence of male alliance in a small dolphin community
Dr Delphine Chabanne and her colleagues have released a new paper showing evidence of male alliance formation among the resident dolphins in the Swan-Canning Estuary. The research reveals strong social and long-term bonds (alliances) among individual males and suggests that these alliances occur in a reproductive context.
Snubfin dolphin census in Yawuru Nagulagun/ Roebuck Bay (prepared by Holly Raudino, Kevin Crook, Ellen D’Cruz and Kelly Waples (May 2022)
A census of snubfin dolphins was undertaken in Yawuru Nagulagun/Roebuck Bay Marine Park (YNRBMP) in May 2022. The census involved vessels following line transect surveys where observers recorded all sightings of dolphins. Photographs were taken of the dorsal fins of all dolphins to identify individuals based on the unique shape and markings on their fins. This information can be used to assess the number of dolphins using the Bay over the time period of the census and to gather life history information on individual snubfins.
Demographics and viability of an estuarine community of Indo-Pacific bottlenose dolphins
The recently published paper in Marine Mammal Science by Dr Krista Nicholson, on the demographics and viability of the resident Peel-Harvey Estuary dolphin community. It was found that the dolphin community of ~90 dolphins is stable although vulnerable to external stressors. There appears to be no immigration into the community leaving death and birth processes and the likely permanent emigration of juvenile males to drive population size. Reduction in adult female and calf mortality is required to maintain the population at its current size.
Niche partitioning among social clusters of a resident estuarine apex predator (Prepared by Dr Krista Nicholson)
This study identified intra-population resource partitioning according to social structure in a resident estuarine dolphin population. The heterogeneity in space use and diet among social clusters may result in individuals being susceptible to different pressures and threats. The dolphins’ foraging behavior and trophic interactions identified them as an apex predator in the Peel-Harvey Estuary, with their collective minimum annual food intake (~ 200,000 kg) exceeding the annual fish biomass removed by commercial fishers. As top predators in the system, dolphins may suppress prey populations through consumption and as agents of intimidation by changing prey distribution and behavior. This study provides scientific basis for recognizing dolphins as an important component of the Peel-Harvey Estuary ecosystem.
Integrating systematic and citizen science surveys for monitoring and management of near-threatened Indo-Pacific bottlenose dolphins in the Swan Canning Riverpark, Western Australia (prepared by Dr Delphine Chabanne and Dr CHandra Salgado-kent)
The aim of this study was to undertake a comparative analysis of spatial and temporal patterns of Indo-Pacific bottlenose dolphin (Tursiops aduncus) sighted in the Swan Canning Riverpark (Western Australia) collected from two survey modes (citizen science and scientific vessel surveys); and thereby inform management directly and plan for ongoing future monitoring.
Minimum Age Estimation of Swan Riverpark Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) using teeth structure as a Determinant.
Data on age at mortality is limited for mammals in general, and more so for marine mammals because of their difficult accessibility. For mammals studied, minimum age at mortality data from naturally deceased animals has been obtained successfully through the analysis of tooth structure. The dentine and cementum layers provide an indication of age because alternating opaque and translucent layers of tissue are laid down annually.
Inconsistency between socio-spatial and genetic structure in a coastal dolphin poplulation
Back in 2013-2015, Dr Delphine Chabanne collected some skin/blubber sample from dolphins. From those samples, Delphine extracted the DNA which was then used to identify the sex of our dolphins and mostly specifically to this recently published study DNA was used to check whether dolphins were genetically connected based on the level of similarity and difference we can find between individual’s DNA.
The results supported that our Swan Canning Riverpark dolphins are genetically connected with dolphins from Cockburn Sound and from other adjacent waters.
Whistle Characteristics of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in the Fremantle Inner Harbour, Western Australia. Centre for Marine Science and technology, Curtin University
Overview: Bottlenose dolphins use whistles to communicate with each other. We recorded 477 whistles of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Fremantle Inner Harbour, Western Australia, on nine occasions over a six-week period during May/June 2013.
Cetacean Morbillivirus in Coastal Indo-Pacific Bottlenose Dolphins, Western Australia.
Overview: Cetacean morbillivirus (CeMV) has caused several epizootics in multiple species of cetaceans globally and is an emerging disease among cetaceans in Australia. We detected CeMV in 2 stranded coastal Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Western Australia. Preliminary phylogenetic data suggest that this virus variant is divergent from known strains. (Stephens et al_2014)
Identifying the Relevant Local Population for Environmental Impact Assessments of Mobile Marine Fauna
Overview: Environmental impact assessments must be addressed at a scale that reflects the biological organization for the species affected. It can be challenging to identify the relevant local wildlife population for impact assessment for those species that are continuously distributed and highly mobile. Here, we document the existence of local communities of Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting coastal and estuarine waters of Perth, Western Australia, where major coastal developments have been undertaken or are proposed. Poster here.
Applying the multistate capture–recapture robust design to characterize metapopulation structure
Overview: To date, bottlenose dolphin studies using mark–recapture approach have focussed on investigating single subpopulations. Here, in a heterogeneous coastal–estuarine environment, we demonstrated that spatially structured bottlenose dolphin subpopulations contained distinct suites of individuals and differed in size, demographics and connectivity. Such insights into the dynamics of a metapopulation can assist in local‐scale species conservation. Summary presentation here.