Plettenberg Bay, South Africa 21 June – 30 June 2024

The Ethical Dilemma of Human Intervention

Predator-prey dynamics of great white sharks and killer whales

The plight of the great white shark, an endangered species facing multiple threats, has taken a controversial turn as killer whales have emerged as formidable predators in recent years. Observations of killer whales hunting and preying on great whites have sparked a heated debate about human intervention in natural ecosystems. This topic delves into the ethical dilemma surrounding whether humans should step in and remove "problem" killer whales or allow nature to take its course. Drawing on firsthand accounts of killer whales hunting great whites and observing the aftermath of such encounters, Nico explores the complex dynamics between these two iconic marine species. The ultimate question arises: should humans intervene to protect the endangered great white shark population, or should we adhere to the principles of natural selection and ecological balance?

Shark cage diving, once a thriving tourist attraction in South Africa's key locations like Gansbaai and Mossel Bay, where great white sharks abound, has encountered a tumultuous shift. The advent of killer whales, perceived as nuisances, preying on great white sharks has disrupted the industry, causing profound repercussions among operators. The economic tapestry of shark cage diving, interwoven with various factors, includes revenue generation from tourists, job creation in local communities, and contributions to the broader economy through spending on accommodations, meals, transportation, and related services. Certain operations even emphasise conservation and education, adding an ecological thread to the economic fabric.

The impact of killer whales on great whites unfolds in multifaceted ways. In regions where killer whales are known to hunt them, the mere presence of these apex predators induces shifts in the behaviour and movement patterns of great whites. Reports indicate alterations in their behaviour and spatial distribution, with sharks avoiding areas frequented by killer whales like Gansbaai and, more recently, Mossel Bay.The stress associated with potential predation may induce physiological effects, impacting the overall health and reproductive capabilities of great white sharks.

As we stand at this ethical crossroad, contemplating the consequences of intervening, we grapple with profound questions. What unfolds when we decide to alter the intricate course of nature? Could our interventions inadvertently disrupt the delicate balance forged over millennia, or are we fulfilling the role of responsible custodians in a planet facing a crisis?

Proposals to cull killer whales deemed as "problem animals" have surfaced, challenging the delicate balance of South Africa's marine ecosystems. Ongoing research and monitoring aim to unravel the behavior, movement patterns, and interactions of killer whales with other marine species. The conservation status and population dynamics of killer whales remain elusive due to their extensive range and limited data. In the quest for solutions, some advocate for non-invasive methods to deter killer whales in recognized great white shark hotspots. Acoustic deterrents, emitting sounds unpleasant to killer whales, and habituation techniques, encouraging avoidance through non-harmful stimuli, emerge as potential pathways to coexistence.

Examining the potential consequences of intervening, including the disruption of predator-prey relationships and the broader impact on marine ecosystems, this topic will navigate the intricate web of ethical considerations. As humanity grapples with its role as stewards of the natural world, the controversy surrounding the intervention or non-intervention in the interactions between killer whales and great white sharks forces us to confront the boundaries between conservation and the preservation of natural processes.


Nico is currently the Research Director at the Shark Research Unit, where his responsibilities extend to overseeing and managing special research projects. He actively engages in hosting research students, providing guidance to postgraduate students, and overseeing the organisation of pertinent data sets. In addition to his academic responsibilities, he collaborates with the local municipality on environmental assessments to ensure informed decision-making regarding environmental concerns. Nico is actively involved in volunteer work within the local and regional stranding networks.

Outside of academia, he serves as the spokesperson for Justice4Jaws, a dynamic NGO dedicated to reshaping public perception of elasmobranchs and advocating for their conservation. Through engaging scientific communication, Justice4Jaws strives to inspire widespread awareness and action for the protection of sharks and rays, fostering a harmonious relationship between humans and marine life.

Nico is a rescue diver and serves as a volunteer with the National Sea Rescue Institute (NSRI) at Station 15. He is a director of the iOcean Investment Trust Foundation, with a mission to empower underprivileged and disadvantaged youth, and impart essential life skills with a particular emphasis on swimming. The foundation recognises swimming as a powerful conservation tool providing an avenue for individuals to immerse themselves in the marine environment, and fostering a love and appreciation of our oceans. The significance of swimming extends beyond the immediate benefits, offering individuals the opportunity to explore previously inaccessible career paths, opening doors to potential careers in the marine tourism or conservation industry, and empowering them to pursue new and impactful professional journeys.

This event takes place on:

Sunday 23 June

14:30 - 14:55