Ecological impacts and behaviour interactions of the notorious invasive lionfish (Pterois volitans)

  • Monica McCard

Student thesis: Doctoral ThesisDoctor of Philosophy


Over the past two centuries, the proliferation of invasive alien species (IAS) has wrought havoc on ecosystems, human health, and economies. Predictions foretell a 36% surge in IAS by 2050, intensifying the complexity and resource demands of their management, often making eradication impractical. To assess population impacts, Functional Response (FR) analysis, a classical ecological method, proves invaluable. This thesis delves into the utility of FR analysis to predict the predator-prey dynamics of lionfish, particularly the juveniles, through controlled laboratory experiments. In chapter one, the thesis provides a historical backdrop on FR metrics, lionfish, and IAS impacts. Chapter two scrutinizes how juvenile lionfish affect macroinvertebrate prey species, revealing prey population destabilization when offered individually and prey population stabilization through prey switching when multiple prey are provided. Chapter three contrasts the effects of juvenile and adult lionfish on prey species, including the commercially significant Nephrops norvegicus, emphasizing differences in prey consumption patterns and prey types. Chapter four evaluates the impact of group behaviour on juvenile lionfish's consumption of prey species, uncovering potential destabilization effects, especially on crab species. These findings also illuminate how conspecific interactions can shape feeding behaviours of other IAS. Chapter five explores lionfish personality traits, such as boldness and shyness, and their relationship with predatory impact. While individual personalities remained consistent, no discernible link emerged between personality and impact, suggesting that other factors wield influence over overall impact. Chapter six concludes by underscoring the significance of this thesis in combining FR and behaviour metrics as a swift tool for assessing and predicting threats posed by emerging or established invaders, thereby aiding in IAS risk assessment. It also offers management recommendations for curtailing the lionfish invasion, advocating for collaborative efforts between researchers and managers to effectively address this ecological challenge.
Date of AwardDec 2023
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorLouise Kregting (Supervisor) & Jaimie Thomas Allan Dick (Supervisor)


  • Functional response
  • Invasion ecology
  • invasive species
  • Feeding impacts
  • feeding behaviour
  • Lionfish
  • Pterois volitans

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