Meeting mammals

The Edges of Earth expedition is on a mission to share untold ocean stories from around the globe. Over the next 24 months, the team will travel to 50 of the most remote dive destinations in the world and Oceanographic will share their stories along the way. In Australia, the Edges of Earth team finds out more about conservation initiatives to protect endangered sea lions.

Words by Andi Cross
Photographs by Adam Moore

Every now and again, I meet someone who I feel like I’ve known forever. A person that I can talk to for hours and not realise how much time has gone by. We can have a mutual interest or conflicting view. Regardless, it enables great conversation and lots of perspective gained. That’s one of my favourite aspects of being on expedition; getting to meet people from all over the world who have incredibly interesting professions, passions and purposeful pursuits.

One person in particular who I have cherished having the chance to meet was Dirk Holman, an Australian sea lion expert. As a Board Member of Australian Sea Lion Recovery Foundation and a Marine Park Ranger with the South Australian Government, my conversations with him were long, rich and extremely insightful when it came to the study and protection of these unique species.

The expedition team and I were making our way to South Australia to further explore the realm of Australian sea lions which also meant that I was going to meet with Dirk in person after many long and fruitful video chats. My goal was to learn as much as I could from the master himself before attempting to get in the water with these highly endangered species. Being  the only listed marine mammal still in decline in Australia, this was a dive to handle with extreme care, guided heavily by expert knowledge.

When we scuba dive with any marine animals, it’s imperative that we understand how to do so safely and sustainability. As divers, we think we do no damage when getting in the water because we’re either skilled enough or we have a passion for wildlife. But the truth of the matter is, that anytime we get in the water, we run the risk of disturbing, hurting or contributing to the problem. Consulting with experts is one way to understand best practices, how to stay safe and how to keep marine ecosystems thriving for those that dive after us.

We arrived in Port Lincoln, a town of approximately 16,000 residents located on the famously beautiful Eyre Peninsula, acting as the main access point to the Great Australian Bight. This vast and dramatic oceanic gulf is located along the southern coast, stretching over 1,160km (720 miles) from Western Australia to the Eyre Peninsula in South Australia. It’s considered one of the most significant and untouched natural areas in the world.

Port Lincoln is known as the seafood capital of Australia, being home to the country’s largest commercial fishing fleet. With such a commercial oriented industry, the local attitudes towards sea lions can often be viewed as competition for fish stocks. It’s been reported that the gillnet and rock lobster fishing industries have had historical issues with by-catch of Australian sea lions and have been significant contributors to the species’ population decline.

To understand the decline of Australian sea lions today requires us to also look back in time. The ‘sealing era’ in the 1800s had a profound impact on these endemic species. They faced severe population decline as they were relentlessly hunted for their valuable pelts, which were in high demand. Their exploitation then, has since had long-lasting consequences now. As a slow-growing and reproducing species (unlike other seal species which breed annually, Australian sea lions only breed approximately once every 18 months), their ability to recover from such extensive hunting has been drastically hindered. Today, the Australian sea lion population has not fully rebounded, and they were uplisted to as Endangered under the EPBC Act (1999) in 2021 because of it.

These sea lions are not to be confused with the Australian fur seal, also hunted extensively through the same era. They have shown signs of recovery, but unfortunately, the sea lion has not. Being such beautiful and charismatic species, it’s devastating to see their numbers declining year after year. With so much pressure on ocean ecosystems, we need to understand more about the stressors driving the decline, and what measures we can put in place to see the species survive and thrive into the future.

That’s where someone like Dirk comes into play. His main focus is population monitoring and understanding as much as possible about the sea lions through this work. When sitting down to lunch, we looked out onto a beautiful ocean view highlighting the greatest hits of South Australia. Calm and peaceful, I knew the ocean was not going to be that relaxed for my voyage out to the Neptune Islands to search for sea lions. Taking it all in, we chatted for hours.

“Australian sea lions are among the rarest marine mammals on earth. Their population is estimated to be less than 12,000 individuals. In 2021, they have been officially listed as an Endangered species in Australia due to decades of unsustainable mortalities from human induced threats,” Dirk explained.

Focusing on colonies in the Dangerous Reef, South Australia, the mid 2000s showed that sea lion pup population halved from 800 to 400 and has stayed at that level ever since. Losing 50% of a population seemed impossible, and yet, Dirk’s research had yet to determine the full cause of the aggressive decline. That’s because previously made assumptions about behaviours or breeding patterns have the habit of being refuted quite rapidly just from observations and feedback from those on the water at different times of the year.

There is little in the way of patterns, trends or correlations to make conclusive findings on how the sea lions live or why a certain colony is not recovering in comparison to another one. For example, two sea lions were tracked from the same colony. They migrated in vastly different directions, went completely different distances, foraged in different depths of water, and ate very different foods. Why? The researchers are unsure, but suspect each colony is made up of individual specialist foragers.

Dirk’s monitoring programs include aerial surveillance (helicopters), land-based cameras at colonies, and temporary pressure activated camera attachments on sea lion’s bodies via a neoprene base, situated on the sea lion with a camera attached to the base.

“There are a handful of individuals in South Australia that are passionately committed to seeing the sea lion population recover. They are studying and working with these amazing animals at every opportunity, and when funding permits. For those who work in this space, there’s such a love for sea lions, that they are willing to spend countless volunteer hours to find ways of restoring this population back to health before it’s too late,” Dirk further explained.

For example, there’s Sea Lion Spotter, which is a citizen-led project to help identify or spot new pups. This allows National Parks and Wildlife Service South Australia’s scientists to monitor population health and trends over successive seasons and is critical in understanding their recovery status. The scientists are mainly focused on pup production numbers as a proxy for population status and trends, and are finding many more colonies each day on remote islands off the coast of Port Lincoln, especially in Spencer Gulf.

Dangerous Reef is a collection of reefs and rocky outcrops, considered one of the most treacherous stretches of coastline in the region. Given the name due to its significant risks to navigation, the reef complex extends for approximately 70km (43 miles) along the coastline and is characterised by submerged rocks, shallow shoals, and strong currents. It was said that nearly 100 sea lions were spotted among these islands that were new to population surveys in past years which is an exciting new development. However, where they fit into the population dynamics and structure of the Spencer Gulf region is still unknown.

Then, there’s The Australian sea lion Recovery Foundation, established by the team behind the movie Sea Lions: Life by a Whisker. This group aims to raise urgent funds needed for critical research, with the leader and spearheading stakeholder being Dirk himself.

Dirk walked us through not only the teams dedicated to protecting these animals, but also what we can do. Because we know so little about this species, getting in the water with them can be confusing. They come off as fun, friendly, curious and playful and are often called ‘puppies of the sea’. However, we never know at what time we are encountering sea lions. For example, they could have just finished what’s called an “episodic central place foraging” session.

This unique behaviour has sea lions embarking on extended dives, typically lasting several days to a week, in search of food. This is driven by their need to secure sufficient nourishment for themselves and their offspring. During the feeding period, Australian sea lions dive to considerable depths, sometimes reaching over 100 meters (330 feet), in pursuit of their prey. They almost exclusively feed on the seafloor, with their diet mainly consisting of octopus, squid, crab, lobster as well as fish and small shark species found in the waters surrounding their breeding colonies, and out on to deeper shelf waters.

Once they locate their prey, Australian sea lions employ their skilled swimming and manoeuvering abilities to catch and consume their food. They also do not sleep whilst at sea foraging. This means after days of non-stop diving at sea, they might be extremely tired and wanting to get to a shoreline to rest and recover. If we intercept them during this grace period, we could be disrupting their much needed relaxation period, before they have to do it all over again. Which could lead to their inability to catch and eat food in a way that will keep them thriving.

Dirk’s recommendation was to dive with extreme care. Keep a distance, don’t overstimulate, and let the sea lions come to us. If they want to explore, they can. But, not the other way around.

On the very last day of being out to sea with Rodney Fox Expeditions for over a week, living aboard Andrew Fox’s vessel, we had a shocking encounter with these magnificent species. Going on a shallow dive in about 2-5 metres (5-15 feet) of water, after only a few minutes of waiting, nearly 30 sea lions began circling us. Remembering Dirk’s words, we kept our distance, hovering carefully above the seafloor.

And just like that, one by one, the sea lions came to explore us—our tanks, fins, cameras and masks. At times they were coming so close to me that I couldn’t believe their interest—it felt surreal and almost as if they were trying to figure out what we were and why we were there. They were gentle, energised and wanting to take the closest look possible. 

Getting the chance to see these animals up close makes you understand why those passionate are so dedicated to the conservation and studying of this population. We felt an emotional bond after only an hour being observed by them. It was hard to leave a site so special.

When we think of sea lions, we think of them in abundance as varying species can be seen around the world. Different species can generally be found in about 20 countries worldwide, distributed across various regions, including the Americas, Europe, Asia, and Oceania. But the reality is they are far from it, and more research is needed to understand what we can do to help restore and protect the populations that are still here with us. It’s critical to share and tell the story of these spirited animals, as we’ve only scratched the surface when it comes to what we know about them.

Bidding farewell to the sea lions was as bittersweet as parting ways with Dirk. From serious chats to laughs around the table, it was uniquely impactful getting a glimpse into his world revolving around sea lions. A world where the bonds between humans and nature intertwine, and the advancement of human knowledge forges on.

Photographs by Adam Moore

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