Critically endangered penguins are directly competing with fishing boats

A new study led by the University of St Andrews has found that critically endangered African penguins (Spheniscus demersus) are much more likely to forage in the same areas as commercial fishing vessels during years of low fish abundance, increasing competition for food and adding pressure on a species already in crisis.

Published in the Journal of Applied EcologyThe research introduces a new metric called “overlap intensity” that for the first time measures not only the extent of space shared between penguins and fishing vessels, but also the number of penguins actually affected by this overlap.

The African penguin population has fallen by almost 80% over the past three decades, partly due to competition with local fisheries targeting sardines and anchovies, key penguin prey.

The local fishery is the purse seine, a large fishing net used to capture schools of fish by encircling them.

Lead author of the study, Dr Jacqueline Glencross from the Scottish Oceans Institute at the University of St Andrews, said: “We wanted a better way to assess how many penguins are potentially affected when fisheries operate in close proximity, not just where overlap occurs. »

Penguins ride fishing vessels in search of food

Using penguin tracking data from Robben and Dassen Island, the team, which included researchers from the University of Exeter, the South African Department of Forestry, Fisheries and Environment and BirdLife South Africa, found a large increase in overlap during years of food shortage.

In 2016, a year of low fish biomass, around 20% of penguins were feeding in the same areas as active fishing vessels. In contrast, in years when fish stocks were healthier, the overlap fell to just 4%.

These results suggest that fishing-penguin competition may intensify when prey is scarce, posing the greatest risk during sensitive periods like chick-rearing, when adult penguins must forage efficiently to feed their young.

Implications for conservation and policy

By quantifying the intensity of overlap at the population level, the study provides a powerful new tool for assessing ecological risks and informing ecosystem-based fisheries management. This also has practical implications for the design of dynamic marine protected areas, capable of responding to real-time changes in predator-prey dynamics.

The African penguin recently made headlines in a landmark court case in South Africa, which challenged the lack of biologically significant fishing closures near penguin breeding colonies.

Earlier this year, the conservation and fishing industry sectors reached agreement in the High Court on the need to close fishing near penguin colonies. In response, the South African government re-established more biologically significant no-fishing zones around Robben Island, one of the main colonies studied.

Dr Glencross added: “This research shows why these closures are necessary. Previously unprotected areas with high overlap intensity are where penguins were most at risk.”