Why is it important to study penguins?
Because penguins spend time on both land and in the sea, the status of their populations often reflects the health of the world’s oceans. Penguins are affected by fluctuations in their environments and can therefore serve as effective indicators of problems in the oceans. In addition, penguins are charismatic and well-loved around the world, which helps to raise awareness and generate support for conservation of their ocean habitats.
The African Penguin (Spheniscus demersus) is an endemic breeding species to Southern Africa and it is the only penguin that breeds in Africa. The African Penguin was South Africa’s most abundant seabird but has suffered a massive population decline. The overall population may have been of the order of 1 million pairs in the 1920s, but it decreased to less than 20 000 pairs in 2012. This rapid decline continues on a daily basis. The species has an International Union for Conservation of Nature (IUCN) Red List status of ‘Endangered’ and is protected under the Biodiversity Act, 2004 (Act No.10 of 2004).
The fragile conservation status of most penguin populations reflects problems in the world’s Southern Ocean, including climate change, pollution and fisheries mismanagement. Penguins are subject to these environmental changes because they travel great distances to migrate and forage. In addition, the condition of penguin populations can serve as an indicator of the marine ecosystems on which they depend. A number of penguin colonies face an uncertain future, which will be tightly linked to the health of ocean ecosystems.
Causes of Decline
Penguins around the world face numerous threats, mainly from oil pollution, overfishing and climate change. For example, African penguins have declined by 90 percent, in part because sardines and anchovies, their primary food, are also sought by large fisheries in the region. In Antarctica, emperor penguins have lost habitat for chick rearing because climate change has reduced sea ice.
One of the contributors to the penguin decline was substantial modification of the habitat at seabird islands due to guano collection. This has forced penguins to nest in the open on the surface of islands, whereas formerly they had been able to burrow into the guano that provides safe and protected nesting. These surface nests are vulnerable to flooding, the eggs and chicks are more accessible to aerial predators and adults and chicks are subjected to heat stress, sometimes causing the abandonment of breeding attempts. Surface nesting may also have rendered African Penguins more susceptible to displacement from breeding sites by larger predators. In addition, some mainland colonies are visited by large numbers of tourists annually and require careful management to avoid harmful disturbance of birds.
At-sea factors are likely to have been responsible for most of the recent decreases of African Penguins. Predation on African penguins at some colonies is considered unsustainable. The main prey of African Penguins is small shoaling pelagic fish, especially sardine and anchovy. The breeding success of penguins is dependent on the availability of adequate numbers of these species to feed on which are sought by fisheries in the region.
Penguins as marine environmental sentinels
- Dee Boersma – Oxford Journals
Scientific knowledge of penguin population trends is meager. We know that many species and colonies are most likely in decline, but we have few systematic counts of colonies. Systematically monitoring the 43 penguin aggregations worldwide would provide the data necessary to determine the status and trend of all penguin species. With this information, scientists could identify trouble spots and intervene before populations crash. Furthermore, the status of penguin populations reflects the state of the oceans they inhabit. Penguins are sentinels, so why not use them?
Life is not likely to get easier for penguins. They have to withstand both climate variation and human development. They may not be able to follow their food as coastal development claims their breeding habitat, or their food may disappear as fishers take more and more of their prey. Climate warming is likely to shift prey species, reduce productivity, and make penguin life more difficult. Climate change, petroleum pollution, and changes in their prey distribution and abundance are causing penguin populations to move and decline. A 10% decline per decade, in the biggest colony for this species, is simply not sustainable.
The changes in penguin populations reflect rapid changes in the marine environment and show that people are doing a poor job of managing the oceans. We are changing the world, the course of evolution, and the species with which we share the planet. Can people change to allow other species to persist and coexist? That is the real question: can we, and will we, manage ourselves?