Decrease Population Due to Human Disturbance

Topics: African Penguin, Petroleum, Robben Island Pages: 4 (1262 words) Published: February 4, 2013
Population decrease of African penguins Spheniscus demersus due to human disturbances

The African penguin also known as the black-footed penguin, is an endangered species confined to the area of south-western Africa. The African penguin is placed in the genus Spheniscus which is derived from a Greek word meaning “wedge”. The species name demersus is also derived from a Greek word that means “plunging”. African penguins are highly distributed around the nutrient rich and cold waters of the Benguela Current, which is also heavily supplied with food. The largest colony of African penguins is found on Dyer Island, which is near Kleinbaai. African penguins spend much of their time at sea searching for food. During the breeding times they gather in rocky burrows or under brush to avoid harsh temperatures. After feeding, the penguins generally return to the same colony and often the same nesting site to breed with their monogamous partner. This species of penguin is currently declining with a two percent population decrease per year. The African penguin was justified as vulnerable from 2000-2008, it was next classified as endangered in 2012 (IUCN, 2012). The decrease in population could be a result of various human disturbances including; commercial fisheries, egg and guano harvesting and also oil spills.

Competition between African penguins and commercial fisheries is often suggested as the main cause of the population decrease. African Penguins feed on small fish but their diet consist mainly of anchovy and sardine. The purse-seine fisheries target to catch schooling epipelagic fish that are the main prey of African penguins. During the breeding season, competition is limited. The penguins, being flightless, are restricted to the nearshore waters where commercial fisheries cannot fish. In contrast, away from the breeding island the competition may be much stronger. Most juvenile penguins spend their first year at sea in areas of intense fishery activity (Nation...
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