A recent study led by the University of St Andrews reveals that critically endangered African penguins (Spheniscus demersus) are increasingly competing with commercial fishing boats for food. This competition intensifies during years of low fish availability, further threatening a species that has seen its population decline by nearly 80% over the last three decades. The findings were published in the Journal of Applied Ecology and introduce a new metric called “overlap intensity,” which evaluates not just the area shared by penguins and fishing vessels but also the actual number of penguins affected.
The penguin population has been devastated largely due to competition with local fisheries targeting key prey such as sardines and anchovies. These fisheries typically use purse-seine nets, a technique that surrounds schools of fish, making it easier for boats to capture significant quantities at once.
Increased Overlap During Low Fish Biomass Years
The research team, which included experts from the University of Exeter, the South African Department of Forestry, Fisheries and the Environment, and BirdLife South Africa, analyzed tracking data from penguins residing on Robben Island and Dassen Island. They discovered that during years of low fish biomass, such as in 2016, around 20% of penguins were foraging in areas occupied by active fishing vessels. This figure dramatically contrasts with years of healthier fish stocks, where overlap decreased to only 4%.
The study’s lead author, Dr. Jacqueline Glencross from the Scottish Oceans Institute, explained the significance of their findings. “We wanted a better way to assess how many penguins are potentially impacted when fisheries operate nearby — not just where the overlap occurs,” she noted.
Implications for Conservation and Fishery Management
The implications of this research extend beyond academic interest. By quantifying overlap intensity at the population level, the study offers a valuable tool for evaluating ecological risks and guiding ecosystem-based fishery management. It can inform the design of dynamic marine protected areas that respond to real-time changes in predator-prey dynamics.
This study comes at a crucial time for African penguins, which have recently been at the center of a significant legal battle in South Africa. A landmark court case highlighted the need for more biologically meaningful fishery closures near penguin breeding colonies. Following a settlement earlier this year, the South African government reinstated important no-fishing zones around Robben Island, one of the key colonies studied in this research.
Dr. Glencross emphasized the necessity of these closures, stating, “This research highlights why those closures are necessary. Previously unprotected areas with high overlap intensity are where the penguins were most at risk.”
As the plight of the African penguin becomes increasingly urgent, this study underscores the critical need for effective conservation measures to ensure the survival of this iconic species. With ongoing pressures from fishing activities, proactive management strategies will be essential in supporting the recovery of penguin populations in the wild.
