White gold

There is an Afrikaans saying, roughly translated to "He is such a good hawker, he would even be able to sell a turd". Today something like this will sound absurd - but a few decades ago people made millions by selling just that - turds, or more specific guano (excrement of seabirds).

This "white gold" has, just like the gold rush in the northern parts of our country, tempted thousands of people all over the world to come and get rich - stinky rich! But who will pay these absurd amounts of money for guano?

Well, in the time of the Spanish occupation of the west coast of South America, guano was extremely valuable to the locals. They would attack anyone who dared bother or kill a seabird.  The excrement of the seabirds, or ‘huano’, as the Spaniards called is, was rich in nitrogen and phosphorus and was used by the ancient tribes as fertilizer.  It was only years later, in the 19th century, that guano became a valued commodity on the international market.

The Southern African resource of guano was first spotted by Captain Benjamin Morrel, the master of an American sealing vessel, who in 1828 visited Ichaboe Island (off the coast of present day Namibia).  In his voyage journal, published in the early 1840`s, he mentioned that the island was covered in a layer of guano 25 feet deep. Not long afterwards, the first ships arrived. To their big surprise and happiness, they soon realised that Captain Morrel's estimate was wrong - the guano layer was 23m deep! News about this traveled fast and a  guano-rush was the result. In a very short period of time, more than 400 vessels moored in Ichaboe Island and more than half the guano was stripped within the first year – more than 90 000 ton in a year!  Because they knew the island would be stripped within the next year, they sought alternatives and found Saldanha Islands also rich in guano. Especially Malgas Island, at the entrance of Saldanha Bay drew attention.  This 8 ha island was covered with a layer guano of 9-10m deep. Within months the island was scraped clean - rock-bottom clean.

The Cape Governor in 1845 tried to rescue what was possible by annexing a few of the island as property of Britain. The legal battle around the “Annexation of Ichaboe and Penguin Islands Act” lasted till 1874.  Meanwhile, the guano trading continued and quite a few islands were scrapped bare, including Bird Island in Lambert's Bay.

Only in 1895, when a new Government Guano Islands Department was formed, things started to slow down and only 700 ton guano was harvested each year. Guards were placed on the islands to supervise and manage the guano operations.  Guano collecting was only permitted after the annual gannet breeding season.

In the early years of the industry, forks, brooms and shovels were used to dig up guano, to spread it to dry and to get it in bags. Stones, feathers and bones were usually removed with large sieves.  Once bagged, the guano was rowed out to the ships in large flat-bottomed longboats called “skuite”.  In the beginning mules and wagons were used to transport the bags and equipment, but later a rail track was constructed for trolleys. Tractors have eased the process in the past years.

The guano yield remained constant from 1895 to the mid 1960`s and then drastically declined.  In 1977, for example only 152 tonnes were harvested.  The decline was a reflection of the collapse of the pilchard stock because of over-fishing.  Pilchard is a small pelagic fish that shoals near the surface in large schools, and is the primary food of seabirds.

The decline in yield, combined with the fact that synthetic fertilizers were becoming a cheaper substitute, prompted the halt of guano scraping in 1972.  However, in the late 1970s Atlas Organic Fertilizers obtained a concession to scrape some of the islands off the West Coast.  Scraping of the Southern African islands was finally discontinued altogether in 1986, and the last stored guano was removed and sold in the mid-1990s.  The most recent wholesale value for the guano was R799/ton.

The scraping of the islands had an enormous effect on the breeding success of penguins and Cape Gannets on our coasts.  Cape gannets construct their nests on mounds made from guano and mud.  Guano scraping created a shortage of nest-building material, resulting the nests being lower than the surrounding terrain.  This made them prone to flooding during heavy rain, increasing the mortality of eggs and chicks.  Gannet colonies were unable to breed during the guano rush of 1845 and many relocated to unexploited islands.

Although scraping was later permitted only after the gannet breeding season, it coincided with the penguin breeding season.  Normally penguins build their nests on well-drained guano, but removal of the fossil deposits forced them to nest in depressions on bare rock which rapidly filled with water, drowning the nest contents.

Guano is not only a useful fertilizer for land crops but it also provides nutrients for marine food webs.  Researchers have demonstrated the fertilizing effect of guano runoff from islands: algae productivity was elevated 2-5 fold and limpets on islands grew faster and reached twice the size of those on mainland sites.  Guano runoff also elevates phytoplankton productivity and has a ripple effect on the pelagic food web.