This story was written by John Yeld and originally published in The Cape Argus on September 9 2013
In an early 20th century photograph, a man stands near the centre of Dassen Island, surrounded by hundreds of thousands of African Penguins. At its height, the breeding colony on the island just off the West Coast at Yzerfontein contained up to a million breeding pairs of the feisty seabird.
But last year, there were just 3 900 pairs, and Dassen Island’s penguin population is falling by 20 percent a year. Globally, there are fewer than 30 000 pairs left.
That’s why Wanless and two researchers – UCT Master’s student Jennifer Roberts and post-doctoral fellow Dr Alistair McInnes – subjected two penguins to a brief indignity last Thursday by catching them and fitting them with satellite trackers. Over the next couple of days, they will do the same to another eight penguins.
BirdLife’s satellite tracking research programme started last year as part of efforts to understand why the penguin population is in such dire straits.
Because the African Penguin feeds exclusively on the “small pelagics” of sardine, anchovy and red-eye, it is a crucial “indicator species” that reflects what is happening more broadly in the marine ecosystem that is important to the country’s economy, contributing 6 percent to gross domestic product.
“The African Penguins are our marine sentinel, our ‘canary in the coal mine’ for ecosystem health,” said Wanless.
While the first phase of the satellite tracking programme looked at the penguins’ foraging ranges and constraints during their breeding season, the second phase is aimed at determining where they go during the couple of weeks between the end of the breeding season and the moulting period.
“This is a critical period in the penguins’ lives,” said Wanless. “By knowing if they stay close to their breeding islands or travel away from them, we can see whether they’re likely to come into competition for food with the commercial fisheries, and whether implementing special management areas will help support marine ecosystem health.”
The 100g satellite trackers cost R30 000 each and another R2 000 a month in satellite “air time”. Their batteries last between 70 and 100 days and the devices are recovered on land when the birds moult, and sent back to New Zealand for replacement batteries and rewaterproofing.