Critically endangered African penguins are increasingly forced to compete directly with commercial fishing vessels for dwindling food supplies, a new study reveals. The research, led by the University of St Andrews, introduces a novel metric—”overlap intensity”—to quantify the extent to which penguins and fishing fleets share foraging grounds, and how this competition escalates when fish stocks decline. The findings underscore the urgent need for improved fisheries management and effective marine protections.
The Growing Competition
African penguin populations have plummeted by nearly 80% over the past three decades, with competition for sardines and anchovies—their primary prey—playing a significant role. The study, published in the Journal of Applied Ecology, demonstrates that penguins are far more likely to forage in areas used by commercial fishing vessels during years with low fish abundance. This competition adds further pressure to a species already facing a severe crisis.
Measuring the Overlap
The research team developed “overlap intensity” to go beyond simply mapping shared space between penguins and fishing vessels. The metric measures how many penguins are actually affected by this overlap, providing a more accurate picture of the ecological risk. Using tracking data from penguins on Robben and Dassen Island, researchers found a sharp increase in overlap during years with scarce food. In 2016—a year of low fish biomass—around 20% of penguins foraged in the same areas as active fishing vessels. In contrast, during years with healthier fish stocks, overlap fell to just 4%.
The Impact on Penguin Survival
The increased competition is particularly dangerous during critical periods like chick-rearing, when adult penguins must forage efficiently to feed their young. When fish stocks are low, penguins are forced to compete directly with fishing vessels, reducing their foraging success and threatening the survival of their chicks. The study highlights the need for ecosystem-based fishery management that considers the impact on vulnerable species.
Conservation and Policy Implications
The research provides a powerful new tool for evaluating ecological risks and informing fisheries management. By quantifying overlap intensity at the population level, policymakers can better assess the impact of fishing activities on penguin survival. The findings also support the design of dynamic marine protected areas that respond to real-time changes in predator-prey dynamics.
Landmark Court Case and Fishery Closures
The African penguin recently made headlines in a landmark South African court case that challenged the lack of biologically meaningful fishery closures near penguin breeding colonies. In response, the South African government has reinstated no-fishing zones around Robben Island, one of the key colonies studied. According to Dr. Jacqueline Glencross, lead author of the study, “This research highlights why those closures are necessary. Previously unprotected areas with high overlap intensity are where the penguins were most at risk.”
The findings emphasize that effective conservation requires a proactive approach to fisheries management, ensuring that the needs of both the fishing industry and vulnerable species are considered. Without such measures, the future of the African penguin remains uncertain
