In this new post, Monica McCard, from Liverpool John Moore University, discusses working on many different non-native aquatic species, with a particular focus on the feeding impacts of invasive lionfish (Pterois volitans).

For over three decades, lionfish have emerged as one of the most devastating invasive aquatic species in history. Throughout the Western Atlantic, these venomous fish have wreaked havoc on reefs and disrupted ecosystems, causing widespread damage that has gone largely unimpeded and unchallenged. In fact, lionfish have been identified as the most ecologically harmful invaders in southern European waters, inflicting significant impacts on biodiversity. The success of lionfish in colonizing new territories can be attributed to a combination of factors. They possess traits such as early maturation and reproduction, enabling them to rapidly populate new areas. Additionally, their venomous spines act as a deterrent to potential predators, giving lionfish a competitive edge. This, in turn, allows them to swiftly establish themselves on reefs, leading to a reduction in biodiversity within the affected areas.

Profile

Starting my educational journey later in life, I brought with me a deep passion and determination that has driven me to where I stand today. During my early days at university, I attended a captivating lecture delivered by Professor Jaimie Dick, an invasion ecologist who later became my mentor for both my dissertation and PhD. In that lecture, he candidly discussed the potentially destructive power of non-native species, leaving me in awe. It was hard to fathom that some of these species were even employed as biological controls to combat pests, despite the often-devastating consequences that followed.

Driven by curiosity, I couldn’t help but question why the impact of such management strategies were not thoroughly considered beforehand. I believed there had to be a way to rigorously test these approaches. It was then that I delved deeper into the realm of prediction methodologies in non-native species, particularly focusing on functional response. This field of study resonated with me, and I knew from that moment that this was the area I wanted to dedicate my research and work to.

The lionfish invasion appears to be unstoppable, and the damage caused is already significant; however, there is still much we have yet to discover about these invasive predators. In the field of environmental science, certain organisms can serve as indicators of pollution-induced changes. I am curious to explore whether lionfish could potentially be one such indicator species. By studying their behaviour and responses to environmental conditions, we may uncover valuable insights into the impact of pollution in marine ecosystems. Although we cannot undo the lionfish invasion, understanding their role as potential pollution indicators could aid in managing and mitigating the broader ecological consequences of this invasion.

As an aquatic ecologist, my primary research revolves around studying the spread and consequences of non-native species, with a recent emphasis on environmental stressors and impacts like pollution. Invasive species offer a unique opportunity to test various ecological and evolutionary theories, as well as how to apply ecological knowledge to effectively manage these significant threats. Moreover, studying invasive species can yield valuable insights into addressing other global challenges, such as climate change. I have led research projects investigating the context-dependent impacts of non-native species in freshwater environments, as well as exploring predator-prey dynamics within aquatic communities.

Where in the world are you?

I am from Northern Ireland but I currently live in Liverpool, UK. The study site I was recently on was in Tela, Honduras. Tela Bay is home to Banco Capiro—visitors to the site have the opportunity to work on a wide-range of projects that help to influence long-term conservation initiatives within the Mesoamerican Barrier Reef. Operation Wallacea (Opwall) offer expeditions to clusters of scientists and field biologists, running a series of wildlife research projects at overseas sites and publishing their results. The surveys are designed when the results across the different surveys are taken together to answer conservation questions and identify any ongoing long-term biodiversity changes. The expeditions are funded by, and rely on, teams of student volunteers who join expeditions for the opportunity to work on real-world research programmes alongside academic researchers. I came to Honduras to set up my own research project and, while I was there, I had the opportunity to intimately observe lionfish and get involved in the dissection and stomach content analysis of lionfish. The project I wanted to set up was an investigation into microplastic accumulation on two different ecosystems on both Tela and Utila. I had the opportunity to go to the site and see first-hand how lionfish eat and hunt and how I could set up and manage a research project.

Lionfish stand as the second most significant threat to marine ecosystems, trailing only climate change. These remarkable invaders have developed an astonishing ability to adapt their behaviour when faced with threats, especially from humans. Their reproductive capability is equally astounding, with a remarkable fecundity rate. Once sexually mature, they reproduce every three to four days, yielding an impressive output of over 15,000 eggs. I have closely examined their feeding rates in laboratory settings, and my findings revealed that the juveniles possess a competitive edge, outcompeting even adult lionfish. My observations in Tela further reinforced this, as the adult lionfish brought in displayed empty stomachs while the juveniles still had prey in theirs. The constant revelations and behaviours displayed by lionfish continue to fascinate me in my research.

With regards to the study site itself, the most surprising aspect is how invasive species can display an impressive ability to adapt to unfamiliar environments, outcompeting native species in the process. Their capacity to flourish across a broad spectrum of conditions is remarkable, and they can even undergo rapid evolution to exploit new resources. The surprising reality is that the global impact of invasive species is vast—they have infiltrated nearly every ecosystem on Earth, often causing considerable ecological and economic harm. Curiously, some invasive species were deliberately introduced by humans for various purposes, such as ornamental plants, agriculture, or as biological control agents. Despite good intentions, these introductions often lead to unintended negative consequences, highlighting the complexity of ecological interactions. Notably, the economic costs associated with invasive species are staggering. Their presence results in massive losses in agriculture, damages to infrastructure, and increased healthcare expenses due to health-related impacts. These financial burdens underscore the need for robust management strategies to curb the spread and impact of invasive species.

Another challenge this ecosystem faces was laid bare when, shortly before my arrival in Tela, the water temperature remained consistently above 30 degrees Celsius due to an intense El Nino event. This led to a widespread bleaching event across numerous reefs. Consequently, there was a noticeable accumulation of macroalgae on the reef, and the presence of certain fish species decreased. As of now, the full extent of the consequences for all species remains uncertain, and we can only speculate. Given the circumstances, there is a pressing need for further research and investigation in this area.

Having personally experienced the destructive effects of rising temperatures on the reef sites, I find solace in the commendable efforts of Opwall in Honduras. Their swift response and adaptive monitoring methods this past summer demonstrate their capability to track and assess any additional changes or impacts. They efficiently adjusted their monitoring approach to comprehend how these changes might affect species in diverse sites. The dive sites in Tela offer an ideal setting for conducting research on various types of reefs across different depths.

Studying ecosystem changes in Tela, Honduras, yields several positive benefits for the conservation and sustainable management of the region’s natural resources and biodiversity. It enables scientists to monitor and assess the status of biodiversity, identifying shifts in species populations and distributions. This data-driven approach aids in the protection of endangered species and the preservation of the area’s unique biological diversity. Moreover, the understanding of ecosystem changes informs the implementation of sustainable resource management practices, encompassing responsible fishing, forestry, and agriculture methods. By considering the carrying capacity of ecosystems and their ability to regenerate resources—these practices ensure the long-term health and productivity of the region’s natural assets. Climate change poses challenges to the region, and its effects on ecosystems are not yet fully understood. However, studying ecosystem changes provides valuable insights into how these ecosystems are responding to climate-related shifts.

The scientific data on ecosystem changes also serves as a powerful tool to influence policymakers and decision-makers. It highlights the significance of safeguarding natural resources and emphasizes the need for measures to mitigate human-induced stress on ecosystems. By involving local communities in the research process, collaboration is fostered, leading to a sense of ownership and empowerment among community members.

Tips for fieldwork

The most common challenge I faced in this study site was mosquitos—I have no idea if this was because of my rich Irish blood, or I was just prone to bites! This was difficult to deal with; however, diving daily helped take the edge off the pain and I just had to stop thinking about it and get on with it. Exhaustion due to the heat and the volume of work was definitely another issue, but, as you are living and working with people in close quarters, you get to know people very quickly and as such we all looked out for each other. This is how it should be.

Diving is undeniably enjoyable, but truthfully, it’s the fieldwork itself that truly captivates me. Whether in a laboratory setting or out in the field, the thrill of contributing to scientific research, as well as being part of something so fascinating and often challenging, is what ignites my passion. This enthusiasm for my work has been ingrained in me since the beginning of my journey, and, as a mother, I’ve always cherished being around my own children and witnessing their learning and growth. When I entered this field, my goal was to share the incredible experiences of participating in research and fieldwork with others. Consequently, I established and managed an outreach program during my PhD journey. I soon discovered that when you share your passion with others, it becomes infectious. The joy of discovery and scientific exploration can be passed on to others, and who knows, one can spark a passion in someone else who might go on to make their mark in the world of research.

The future

I have recently embarked on a new journey as a lecturer in environmental science at Liverpool John Moore’s University, and, to my delight, I got the opportunity to visit Honduras, which has always been a dream destination for me. During my first dive there, I was completely awestruck by the sheer beauty of the place. It felt surreal to be part of a mission aimed at removing invasive lionfish from this magnificent environment. Interestingly, my fascination with lionfish and their invasion began with the knowledge that they were first released in Florida, making it a place I had always wanted to study them. Now, after being in Honduras, I feel even more motivated to make a positive impact on their management and conservation. While my passion lies in studying lionfish, I’ve nurtured a longstanding aspiration to fully immerse myself in the depths of the ocean, conducting research on the ecological impacts affecting the corals of the Great Barrier Reef. Additionally, I yearn to witness the captivating sight of lionfish flourishing within their innate Australian habitat.

Becoming an invasion ecologist has made me realize that this field is my true passion. I am wholeheartedly dedicated to finding effective ways to remove and manage these destructive invasive species. My drive to work on non-native species stems from the desire to generate scientific knowledge that directly informs conservation and management decisions. I am determined to contribute to the protection of native ecosystems and wildlife by tackling the challenges posed by invasive species head-on.