Impact of parasites on penguins discussed

* Dr Marcela Espinaze at the Cape Research Centre in Tokai.

Overfishing and the natural migration of sardines from the west to the south coasts are making it harder for penguins to find food, but these charismatic sea birds are themselves a source of nourishment for parasites more commonly associated with the family dog – fleas and
ticks.

Bug expert Dr Marcela Espinaze has been probing nests, feathers and even penguin poo at local colonies to learn more about the effects of these tiny parasites on the African penguin. She spoke at the Cape Research Centre in Tokai about her findings .

The global African penguin population is estimated to be only 25 000 breeding pairs, and the birds are now classified as endangered, according to the International Union for Conservation of Nature red list.

African penguins (Spheniscus demersus) – previously known as jackass penguins for their loud, donkey-like bray – have declined by more than half since the beginning of the 1900s.

The species inhabits 24 islands and four mainland colonies from central Namibia to the Eastern Cape.

Dr Espinaze, a recent graduate in the Department of Conservation Ecology and Entomology at Stellenbosch University, studied the parasite loads on penguins from five colonies (two mainland colonies at Stony Point and Simon’s Town and three island colonies at Dassen, Dyer, and Robben islands) along the south-west coast of South Africa.

The aim of the study was to record the diversity and abundance of parasites on African penguins and to assess their impact on overall penguin health.

The only other ectoparasite study was done in 1980 and focussed on the population dynamics of soft ticks on African penguins at Marcus Island along the west coast.

With the help of CapeNature colony managers and SANParks rangers, Dr Espinaze collected parasites from penguin nests, feathers, around their eyes and blood. She also collected poo from penguin chicks to check for worm parasites.

Back in the laboratory, she found that a typical penguin flea was the most prevalent ectoparasite on penguins and in their nests, followed by a typical seabird soft
tick.

“And a new record of the sticktight flea (also known as the hen flea and a common parasite on rodents and poultry) was found on African penguins and only on Dassen Island,” said Dr Espinaze, who is originally from the Chilean Patagonia and now lives in Stellenbosch.

“In general, penguin chicks harboured more parasites than adult penguins. This is not surprising because adults spend much time at sea catching fish,” she said.

Mainland colonies recorded higher parasite abundance and prevalence compared to island colonies.

Particularly, Simon’s Town recorded more fleas and Stony Point more ticks, and a higher prevalence of blood parasites and worms than other colonies.

Mainland colonies exhibited higher nest density compared to island colonies, which might be an important factor driving the high parasite loads, she said.

Dr Espinaze said seasonal changes also influenced parasite loads, with a spike in fleas and ticks from autumn to spring. Overall the study had shown that parasite
infestation of penguins and their nests differed across colonies, and particularly that penguin chicks were more vulnerable during warmer months.

“We believe this study has important information for management decisions that can potentially affect the conservation of this endangered penguin species,” said Dr Espinaze.