Endangered penguins are running out of food and Exeter research reveals why

New research involving a University of Exeter scientist has shown that critically endangered African penguins are being forced to compete directly with fishing vessels for their food, particularly in years when fish numbers are low.

The study, led by the University of St Andrews with contributions from Dr Richard Sherley from the University of Exeter’s Centre for Ecology and Conservation, examined how often penguins and commercial fishing boats use the same waters while searching for sardines and anchovies.

African penguins have declined by nearly 80 per cent over the past three decades, and competition with fishing boats – which use large nets to catch schooling fish – is one of the key pressures on the species.

To understand this competition more clearly, researchers developed a new measure called “overlap intensity.” 

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Rather than simply looking at where penguins and fishing vessels happen to be at the same time, the measure shows how many penguins are actually affected when boats operate in the same feeding areas.

Using tracking data from penguins on Robben and Dassen Islands, the researchers found that the level of overlap changed dramatically depending on the availability of fish. 

In 2016, a year with very low fish abundance, around one in five penguins were found to be feeding in the same areas as active vessels. 

In years when fish stocks were healthier, this dropped to about one in twenty. The study suggests the risk to penguins increases most during difficult feeding years, especially when adults are raising chicks and need to find food quickly.

Dr Sherley said the new method provides a clearer picture of how fishing activity affects wildlife and could help shape fishery management that protects both penguin populations and the fishing industry.

The findings were published shortly after a major court case in South Africa challenged the lack of fishing closures near penguin colonies. 

The case resulted in the reinstatement of no-fishing zones around Robben Island, one of the main sites included in the study. Researchers say the new evidence helps show why such protections are necessary.