Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors
The latest Paper of the Month for Parasitology is ‘Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors‘ by Dr. Marcela Paz A. Espinaze Pardo
The African penguin is an endemic species and one of the most charismatic seabirds in Southern Africa. The African penguin population was estimated at millions of individuals at the beginning of the 1900’s. Since then it has experienced a severe population decline and is now classified as an endangered species according to the IUN red list. Currently, the global African penguin population is estimated to be only 25,000 breeding pairs, inhabiting 24 islands and four mainland colonies distributed from the central coast of Namibia to the Eastern Cape of South Africa. The contribution of parasites as potential causes of the African penguin population decline is still unknown. A perceived increase in ectoparasite loads led conservation authorities to question the impact that these parasites could be having on overall penguin health and breeding productivity. The little information on parasite diversity associated with wild African penguins and the factors driving parasite demography has motivated this study.
We were fortunate to visit five African penguin colonies: two mainland (Stony Point and Simon’s Town); and three island colonies (Dassen-, Dyer-, and Robben Islands) on the south-west coast of South Africa. We collected ectoparasites, blood parasites and helminth parasites from the penguins, and ectoparasites from their nests.
We found that a typical penguin flea (Parapsyllus humboldti) was the most abundant and prevalent ectoparasite on penguins and in their nests, followed by a soft tick (Ornithodoros capensis s. s.). A new record of the sticktight flea (Echidnophaga gallinacea) was found on African penguins and only on Dassen Island. Blood parasites from the order Piroplasmorida/Haemospororida and helminth parasites from the genus Cardiocephaloides were the most prevalent infecting penguins across colonies. In general, penguin chicks exhibited more parasites than adult penguins. 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 higher prevalence of blood parasites and helminths than other colonies. Mainland colonies exhibited higher nest density compared to island colonies, which might be an important factor driving the high parasitic loads. Similarly, past studies have recorded an east-ward shift of the penguin`s fish prey distribution, with a higher helminth infection of that fish around the mainland colony areas. This could have contributed to the high prevalence of helminth parasites found in mainland compared to island colonies. The season of the year also seems to play an important role in the variation of parasitic loads of penguins and their nests. In particular, ectoparasites (fleas and ticks) and blood parasites increase in spring (October-November) compared to autumn/winter (May-July). This study has shown that parasite infestation of African penguins and their nests in the Western Cape differ across colonies, and particularly penguin chicks are more vulnerable during warm seasons of the year. We believe that this study is a step forward to elucidate the factors that affect the parasite populations associated with African penguins, and therefore, that can potentially affect the conservation of this endangered penguin species.
The paper ‘Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors‘ by Dr. Marcela Paz A. Espinaze Pardo is available free for a month.