Why African Fish Eagle is under threat of extinction

By Rupi Mangat

Published: East African Nation 11 July 2011

Above: Shiv Kapila releasing African Fish Eagle. Copyright Shiv Kapila

The African fish eagle is one of Africa’s most charismatic raptors. Donned in a copper-coloured mantle with a clear white collar, its very presence commends respect. Its loud and distinctive call is unmistakable – once heard, always remembered – the call of Africa. Its hunting prowess is legendary – it can spot a fish from the highest tree and swoop with talons outstretched to scoop it out of the water. Many a wildlife film has been shot on this powerful hunt.

“The African fish eagle is an apex predator,” enthuses Shiv Kapila who has been studying the birds since 2009 – first at Lake Naivasha under the mentorship of one of Africa’s foremost raptor scientists, Dr Munir Virani – and then restarting research at Lake Baringo. Both fresh water lakes in the Great Rift Valley once hosted huge populations of the bird that has a wingspan of eight feet.

A hunting fish eagle at Lake Naivasha. Copyright Shiv Kapila (800x533)
A hunting fish eagle at Lake Naivasha. Copyright Shiv Kapila

Apex predators are known as top-level predators because they have no predators of their own and reside at the top of their food chain. “They are very useful in assessing the health of an ecosystem,” continues the young researcher who comes from a renowned family of Kenyan lawyers – the Kapilas. Shiv broke the tradition when he veered into natural sciences. “I studied geology for my under-graduate but then found living things more interesting to study then just rocks,” he jokes.  In 2009, he graduated with an M.Sc from University College London and returned home to continue with his research on the African fish eagles.

Call of Distress

“Lake Naivasha and Lake Baringo were the domain of the African fish eagle,” states Shiv.

“Lake Baringo is interesting,” continues Shiv who is now funded by the Peregrine Fund to continue with his research. “Compared to Lake Naivasha, it’s quite isolated and completely untouched by flower farms. It’s the only fresh water lake in northern Kenya’s semi arid region but human settlements are increasing around the lake.

“After a five-year lull at Baringo, we have found suspected Furadan abuse in the region,” states Shiv. His statement sends a chill down my spine for Furadan is a lethal substance that kills fast. Furadan is the trade name for Carbofuran, one of the most toxic carbamate pesticides.

Pastoral people have found another use to it. Where predators like lions and hyenas kill their livestock, they lace the carcass with Furadan. Africa has lost huge populations of lions, vultures and other species to it. A grain can kill a human child yet it continues to be sold under the table and in some cases under another brand name. Ironically USA, the country that manufactures it, does not sell it at home and despite volunteering to buy back stocks, the lethal toxic is still found in Kenya and neighbouring countries. In western Kenya, it’s used to catch water birds for human consumption.

“At Baringo, it’s used to target crocodiles,” continues Shiv. These are crocodiles, which are suspected to have preyed upon the pastoral people’s goats. Fish are deliberately laced with the poison and dumped on shore for the crocs. When the fish eagles prey on the poisoned fish, they become the innocent victims.

Shiv Kapila with strongly leucistic fish eagle at Lake Baringo . Copyright Shiv Kapila (800x532)
Shiv Kapila with strongly leucistic fish eagle at Lake Baringo . Copyright Shiv Kapila

 

“In 2005, there were 35 adult African fish eagles recorded,” Shiv reels the statistics. “In October 2010, we found 18 adults and two juveniles. That’s when we learned of the major poisoning by Furadan.

“In 2006, 13 African fish eagles perished in just one incident because a farmer laid poison-laced bait where he saw crocodiles going for his goats.”

Shiv explains the huge number killed because under normal conditions these birds are not gregarious like vultures.

“African fish eagles are very territorial and will defend their territories ferociously but when there is a glut of food, they will allow others into their territory. In this case, there was a glut and so there were many African fish eagles in the area.

“Ironically, Furadan kills everything. In this case it even killed one of the goats that the farmer was trying to protect.

“Since then, the populations have not recovered. Part of the reason is the lake’s bearings. The population of the African fish eagles is isolated because it is too far from Lake Naivasha.”

A small isolated population translates into a limited gene pool and increased in-breeding which leads to genetic mutations.

Shiv Kapila holding African Fish Eagle. Copyright Shiv Kapila (532x800)
Shiv Kapila holding African Fish Eagle. Copyright Shiv Kapila

Incidences of genetic disorders were discovered while Shiv, along with Simon Thomsett, Kenya’s raptor expert, was helping a Kenyan student studying in South Africa, looking at the toxicology of the lake. It involved trapping the fish eagles at both the lakes and drawing blood samples. At Baringo, seven of the eight birds trapped had genetic abnormalities such as leucism, which is the lack of pigmentation in certain areas of the plumage. It’s a frightening figure for in normal circumstances, leucism is present in only 0.1 per cent of the population regardless of whether it’s humans or the fish eagles.

Simon Thomsett with rare Bearded Vulture, Copyright Simon Thomsett (800x600)
Simon Thomsett with rare Bearded Vulture, Copyright Simon Thomsett

“With such a high proportion of leucism in the African fish eagle we assume that it is due to genetic inbreeding,” says Shiv. “This has severe implications. It can mean that a single outbreak of a disease can wipe out the entire population.”

But Baringo has more on its plate, which adversively affects the powerful raptor. The invasive species such as the invasive weed, Prosopis julliflora or locally called ‘Mathenge’ out competes the acacia woodlands around Baringo.

“The fish eagles only breed when they find the perfect place which would be the tallest Acacia tree,” explains Shiv. Now there’s only one nest in Baringo and even that is not on an Acacia but a Kapok tree, which is a native of South America.

In comparison, there were five pairs recorded on Ol Kokwe Island in Lake Baringo in 2005 of which three were breeding. In 2011, there is only one a pair recorded on the island and even that’s not breeding because the island is bare of acacia woodland thanks to the demand for charcoal. Closer on shore, two fledglings were recorded in February 2011.

Parallels can be drawn with Lake Naivasha where the shores have also been cleared of acacia woodlands. Only a few groves remain on private properties.

Both lakes also suffer from increasing drop in water levels. “Fish eagle densities are closely correlated to fishing perches and shorelines,” states Shiv. He explains by drawing a chart. “As the lake shrinks, the fish eagle has to fly further to catch its quarry. This lessens its chances because by the time it flies to the fish, the fish has got away.

The renowned ornithologist, the late Leslie Brown, first documented the African fish eagles. In 1970, he recorded 75 individuals around Lake Baringo. The 2004 count was 35, and in 2010, 20 were recorded.

Naivasha’s crisis

Despite it being a Ramsar site – a water body of international importance that should be conserved and used sustainably – there’s little to show for it. Construction in the riperian zone continues with chemicals and waste from the farms flowing in.

In 1970, Brown recorded 224 African fish eagles around the lake. Munir and Shiv’s count in 2010 was 120 despite the drought of 1997, which saw the population crash to 62. 2010 was a good year for the birds because of the increase in the lake level due to the rains. 24 of the 32 fish eagle nests were active.

“Lake Naivasha is an amazing lake,” says Shiv. “It’s under such severe pressure but it’s miraculously still there. Its water level should be four metres higher than what it is but it’s not so because of unregulated water abstraction by people around the lake. 15 years ago, the lake was perfectly clear. It had submerged plants, which kept the lake translucent as the roots firmly anchored the soils. Ironically the three-month fishing ban at Lake Naivasha every year has allowed the crayfish and the carp – both foreign fish in the lake – to flourish. The carp came to the lake in 2001 having escaped from a private fish farm and into a river flowing into Naivasha.

“Both fish are bottom feeders and have eaten the plants that has contributed to the lake’s muddy appearance. Hence the African fish eagle can’t see its prey.”

I ask Shiv how long the African fish eagle has in the face of the present situation. “If nothing is done,” he replies, “15 to 20 years and that is being optimistic.”

Africa without its African fish eagle will be like Australia without its kangaroo.

 

 

 

 

 

 

 

 

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