Trouble for gannets and other seabirds in South Africa


Cape gannetFrom the Cape Argus in South Africa:

South Africa: Gannets Face a Sea of Troubles

January 26, 2007

The beautiful Cape Gannet, an iconic species of the local coastline that has lent its name (in Afrikaans, Malgas) to places like Malgas Island in Saldanha Bay and the village on the Breede River, is in trouble.

The gannet is one of three endemic seabirds that occur naturally only on the Cape and southern Namibian coasts (the others being the African Penguin and the Cape Cormorant), and it breeds at just six sites, three each in South Africa and Namibia.

Once numbering in their hundreds of thousands of breeding pairs, the population of this species on the West Coast has crashed and it now faces a daunting array of threats, says leading Cape Town ornithologist Peter Ryan, an associate professor at UCT’s FitzPatrick Institute of African Ornithology.

In an article in the next edition of Africa – Birds and Birding titled “Going, going Gannet …”, Ryan explains why the gannets – and also the penguins and cormorants – are in a major biological crisis.

All three birds use the food chain in the highly productive Benguela ecosystem off the West Coast.

Cape Gannet threatened with extinction: here.

African penguins: here.

Wildlife Extra: African penguins suffer under stormy weather conditions: here.

2 thoughts on “Trouble for gannets and other seabirds in South Africa

  1. Penguins saved by marine zone

    2010-02-10 19:04

    Paris – A ban on fishing around a colony of threatened penguins in South Africa has brought swift benefits to the beleaguered birds, marine biologists reported on Wednesday.

    The population of the African penguin (Spheniscus demersus) fell by 60% between 2001 and 2009, driven by a plunge in anchovies and sardines, with climate change and purse-seine trawling fingered as the main culprits.

    Of the 26 000 surviving pairs, the biggest colony is on St Croix Island in Algoa Bay, on the eastern coast of South Africa.

    There, experts tagged adult birds and monitored them before and after a ban on purse-seine fishing that took effect in a 20km radius from January 2009.

    Before the ban, 75% of the penguins had to venture beyond 20km to find food, they found.

    Three months after trawling was stopped, 70% of the birds were feeding within the 20km zone, tucking into fish that now became available.

    ‘Endangered’

    Fifty kilometres away at Bird Island, there is also a large colony of African penguins, but fishing there is still permitted. The birds are still doing long-haul swims to find food, the investigators found.

    The finding is important because the St Croix birds have decreased their daily energy expenditure by 40%, “enabling them to invest energy in reproduction,” said David Gremillet of France’s National Centre for Scientific Research (CNRS).

    It is too early to say whether the penguins will have more chicks and how many of the youngsters will survive until adulthood.

    “It’s something that has to be studied over the long term,” Gremillet told AFP. The species is likely to be classified as “endangered” this month because of the sharp decline in the last decade.

    The study, published by Britain’s Royal Society in the journal Biology Letters, provides the first evidence about how quickly a threatened species can rebound when it is given a little help.

    “A marine protected area closed to fisheries can have immediate benefits for an endangered marine top predator,” say the authors.

    Purse-seine fishing entails dropping a balloon-shaped net, or purse, to a certain depth and then raising it underneath shoals of fish that swim near the surface. The technique prevents the fish from swimming down to avoid capture.

    – AFP

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  2. Pingback: South African seabirds and climate change | Dear Kitty. Some blog

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