Published 16th April 2026

Dolphins are at the heart of Mandurah, not just as a beloved sight on the water, but as an important indicator of the health of our entire estuarine ecosystem. Our inland waterways are home to a thriving population of Indo-Pacific Bottlenose Dolphins, whose presence reflects the balance of this unique environment. Marine biologist Dr. Krista Nicholson has dedicated years to studying these incredible animals, uncovering how they live, interact, and what shapes their survival. In this blog, we explore her key findings into the biggest factors currently impacting Mandurah’s dolphins.

the importance of incident research

Dr Krista’s incident research is an ongoing and vital part of understanding Mandurah’s dolphin population. Each report is carefully recorded and shared back with the wider community, helping to build awareness and improve education around how these animals are impacted. Dolphin identification, including names and individual fin identification, is also shared between researchers and the wider community, so when an incident is witnessed, it can be accurately linked to the right dolphin and added to their individual history. This shared approach creates a clearer, long-term picture of each animal’s wellbeing along with the overall wellbeing of the population. In Mandurah, the biggest risks dolphins face are stranding and entanglements, making timely reporting and accurate records especially important for their protection and effective response efforts.

At its core, this work is about connection. The more people can recognise and relate to these dolphins as individuals, the more likely they are to care, report concerns, and actively look out for their protection. It’s a proactive approach built on prevention over cure, using knowledge and community awareness to help reduce harm before it happens.

Stranding

Mandurah is a known live-stranding hotspot for dolphins, with many individuals experiencing stranding at least once, and in some cases multiple times throughout their lives. During the warmer months, dolphins often move into the extremities of the system, including shallow rivers and lakes accessed via shallow channels in search of food. When the tide recedes, they can become trapped in isolated pools between sandbars (confinement stranding) or left completely exposed on sand (high and dry stranding).

The risks of stranding are serious. When dolphins are out of water, their body weight places immense pressure on internal organs, which can begin to fail if exposure is prolonged. Unlike land mammals, dolphins have skeletons adapted for swimming through the water rather than weight-bearing on land, meaning they are not able to support themselves under lands gravity. The longer an animal remains stranded, whether fully out of the water or confined to a shallow pool, the lower their chances of survival, making rapid response and relocation into deeper water critical. Prolonged exposure can also lead to dehydration and sun damage, as the protective mucus layer on their skin dries out, potentially causing long-term scarring. Importantly, many dolphins that survive a stranding can return to normal life and remain reproductively active.

Research into these events focuses on understanding how dolphins use these environments and identifying the environmental conditions, such as tidal cycles and water levels, that contribute to stranding events. This helps build a predictive understanding of when higher-risk situations may occur. Krista’s studies also examine the behaviours and environmental triggers leading to strandings, with findings suggesting that most affected animals are otherwise healthy individuals caught out by misadventure rather than illness or weakness.

Stranding stories: Crook

Crook’s story is a powerful reminder that not all stranding events are directly witnessed. In February 2009, he was observed with extensive sunburn, likely the result of becoming stranded during a period of extremely low tides in the days prior. Although the incident itself was never seen, the evidence was clear when he returned to the estuary, his skin showing significant damage from prolonged exposure. Today, Crook carries lasting signs of that event. He has extensive white scarring across his body from the sunburn, and his dorsal fin is now almost completely bent over to the right, giving him a smaller overall appearance. Despite this, Crook remains a resilient individual. He continues to move strongly through the waterways and is often seen alongside his alliance mates, Ruby and Tooth, actively pursuing females, a testament to the ability of dolphins to survive and adapt even after significant incidents.

Stranding Stories: Karenina

Karenina’s experience highlights again the hidden nature of many dolphin stranding events. When she was sighted in November 2018, she showed severe sunburn across her back, clear evidence she had been stranded and exposed for a period of time before returning to the estuary unnoticed. Years later, Karenina made an unexpected journey, travelling to the Leschenault Estuary in Bunbury. After disappearing from Mandurah in August 2024, she was confirmed there in January 2025 alongside five other dolphins, marking an extremely rare movement between the two systems. During her time away, she stranded again, reinforcing how common and recurring these events can be for individuals exploring unfamiliar or shallow environments. She now carries large white patches of scarring from these strandings, lasting reminders of the risks dolphins face.

Entanglement

Fishing line entanglement is one of the most significant threats to dolphins worldwide, and it is a very real issue for Mandurah’s local population. Calves are especially at risk due to their playful and curious nature, often interacting with floating seaweed or debris where discarded fishing line can be hidden. What may begin as a loose wrap can quickly become life-threatening, as the line tightens over time, cutting deeper into the skin and eventually into muscle and bone. This can result in severe deformities, restricted movement, amputations, and chronic infections that may impact the dolphin for life, or in some cases even take its life.

Entanglements can also interfere with a dolphin’s ability to swim efficiently, hunt, and socialise, placing additional stress on already injured animals. In many cases, dolphins may carry these injuries long-term if the line is not removed, also often increasing their chance of re-entanglement. Disentanglement is a complex and delicate process, requiring trained responders and often multiple attempts, as the animals are mobile, strong, and already under stress. While these interventions are critical, they are not without risk to both the dolphin and rescuers.

Research both locally and globally continues to refine rescue techniques and improve response outcomes, but the strongest focus remains on prevention. Encouraging responsible fishing practices is key such as avoiding cutting lines where possible, retrieving lost gear, and using designated disposal points like “reel it in” bins all help reduce the amount of line entering the waterways. Public awareness plays a huge role, as many entanglements are preventable with simple changes in the community. The message is clear, prevention over cure offers the best chance of protecting these animals from harm.

Entanglement stories: Nikki

Nikki’s story reflects the lasting impact that both stranding and entanglement can have on individual dolphins. She is easily recognisable by her distinct half dorsal fin, the result of a past entanglement in fishing line that became tightly wrapped around her body. Over time, the line cut deeply through flesh and bone, ultimately leading to the amputation of part of her fin. Nikki has also experienced multiple stranding events across her life, including in 2006, 2009, and March 2026, highlighting just how frequently these incidents can occur for even well-established individuals within the population. She is also one of the oldest known dolphins in the population, a respected matriarch and a mother and grandmother to many individuals within the community. Her longevity and lineage highlight her importance within the social structure of the local dolphin population, making her survival even more significant.

Entanglement Stories: Luca

Luca’s story is a heartbreaking reminder of how quickly entanglement injuries can escalate. Luca was a young, playful dolphin known for his curiosity and love of interacting with seaweed. Sadly, this same curiosity also increased his risk of encountering fishing line. In his just 18 months of life, Luca was entangled three separate times. The first incident in February 2019 saw fishing line wrap around his pectoral fin, body, and mouth, causing significant injury before he was eventually rescued. A second entanglement in June 2019 affected his dorsal fin and tail fluke, requiring further rescue and treatment to support his recovery. Despite repeated intervention efforts, Luca was found entangled again shortly after. During a final surgical attempt to remove embedded line and damaged tissue, it was discovered he had developed a severe bone infection linked to his first entanglement. He sadly passed away during surgery.

For more

Thank you for joining us in learning Mandurah’s dolphins and the research that helps us understand them through exclusive interviews with Dr Krista Nicholson. Keep an eye on this page for more to come about our dolphins in collaboration with Dr Krista including the all new “Dr Krista’s Dolphin Diaries”.

Read more about our support for the Mandurah Dolphin Research Project here.

Delve deeper into Dr. Nicholson’s studies here.

Learn more about Luca’s story and the Clean Waterways Campaign that followed his death here.

If you’re feeling inspired, there are plenty of ways to get involved, from citizen science projects to volunteer programs and community initiatives, all making a real difference in protecting these iconic dolphins.

Save the dolphins through awareness, action, and care.

Dolphin images courtesy of Estuary Guardians & Dr Krista Nicholson.