Penguins are in decline around the globe, none more-so than the African penguin, also known as the jackass penguin. Michaela Strachan delved into the world of African sea-bird conservation in her series The Great Penguin Rescue and found out what the main problems for these charismatic creatures are.
The major issue that African penguins face on the coastline of South Africa is an overall lack of food. Fish stocks are in decline worldwide due to an increase in commercial fishing and this felt by animals further up the food chain. African penguins rely heavily on the availability of fish, and with dwindling numbers this means that each individual has to swim further to catch the fish it needs to feed itself and any offspring.
Another recent problem that may be affecting fish stocks is climate change. As the average temperature of the sea increases, the sea water loses its ability to hold dissolved oxygen. This means that the wildlife previously adapted to a particular area may have to move in order to find more favourable conditions. This could have moved the African penguins' fish prey further round the coast or out to sea.
We may immediately think of the devastation of an oil tanker wreckage when we associate oil with sea-life, and although those instances are catastrophic, they are also rare.
Are more prominent issue is oil leaking from ships as they traverse the shipping lanes, several of which pass by African penguin colonies.
Oil coats seabirds feathers, causing them to clog together lose their structure. Oil coated sea birds can die from exposure to hot or cold temperatures, depending on their location. Preening is a necessary daily activity for birds to keep their feathers in check, and an oil coated bird may ingest large quantities of oil while trying to clean itself.
For penguins the specific issues are around their buoyancy and their hydrodynamics for swimming in water, both affected by any coating of oil.
Cape fur seals naturally compete with African penguins for breeding space and food resources, however there are also instances where seals have learned to hunt penguins. This is probably in response to the reduction in available fish stocks, their natural prey, as mentioned above.
Other predators include feral cats, mongoose and some bird species. When on land, penguins are relatively easy prey for terrestrial predators, whilst their chicks and eggs are easy pickings when not watched closely by attentive parents.
African penguins lay their eggs on land, and for those whose colony is on the mainland human land development is a major issue.
Houses, roads and even golf courses pose various threats to penguins rearing their young while development of land also reduces the available area for those colonies.
More of a historic problem is guano, penguin excrement, collection.
Guano is was used as source of nitrogen fertiliser by farmers and was heavily harvested in the 19th century. African penguins used to make their nests inside the deep layer of guano around the coast, however, due to heavy harvesting the penguins are now forced to make bare nests, open to the elements.
Thankfully, guano collection in now illegal, however due to its scarcity it is still remains a problem for the African penguin population.