Marc Springer
15 August 2008
NAMIBIA'S fledgling oyster industry was poised for rapid expansion and seemed destined to become a significant role player in the production of this sought-after delicacy.
Now two successive red tide events have left this potentially highly lucrative sector counting its losses and facing an uncertain future.
"We have lost up to 90 per cent of our oysters to the algae bloom which occurred in March this year and was followed by another one in May," says Claus Deckenbrock, Managing Director of Seafresh Investments.
But he is quick to add that his company will recover from this "major setback" and not only learn from but adapt to it.
Algae blooms occur during certain weather patterns which result in the upwelling of cold, nutrient-rich seawater from the ocean floor into inshore coastal waters.
The high nutrient content allows phytoplankton to bloom to unsustainable levels, using up all the nutrients in the water and then dying off.
Bacteria begin to feed on the dead algae, using up oxygen in the water and resulting in all sea life that cannot move away from the affected areas, such as oysters, to perish.
The two red tide events this year were particularly devastating because they were associated with sulphur eruptions, resulting in large volumes of sulphide gas being released and bubbling through the seawater.
This substance also depletes oxygen in the water, which oysters need as much as any other living organism.
The two consecutive outbreaks in the Walvis Bay lagoon have severely unsettled the whole industry, in particular those companies operating in a newly established 1 250-hectare aqua park that was created in an area belonging to NamPort.
All seven oyster farmers active on the site in 2007 produced Pacific oysters (Crassostrea Gigas), which do not naturally occur in Namibian waters.
"Our insurance company commissioned a study which concluded, that red tide events of such severity occur once every 30 years," says James West, director of Seafresh Investments.
"Now it has happened twice in three months and left the whole industry deeply concerned about a recurrence of the problem".
The majority of Seafresh's production is exported to China where, as elsewhere, Namibian oysters are considered among the best in the world due to their exceptional taste and favourable meat-to-shell-ratio.
"The Asian consumers are very particular about oysters and have very distinct preferences when it comes to factors like size, form, texture, taste and colour," explains Deckenbrock.
"Given the high economic growth in China, where consuming oysters is regarded as a luxury and status symbol, we expect the demand there to increase and with it the importance of that market to our company."
Namibia, which exports about 62 per cent of its oysters to South Africa, is generally considered to have a comparative advantage to other oyster-producing countries.
This is mainly due to the Benguela current, which, through a process of upwelling delivers, vast amounts of nutrients needed to grow molluscs successfully.
Additionally, Namibian waters are by and large free of pollutants that contaminate the ocean in other countries where oysters are grown, resulting in increased mortality and inhibited growth rates.
"It takes us about half the time needed by producers elsewhere to grow an oyster to marketable size," says Deckenbrock.
This translates to between six and 10 months for a cocktail to medium-size oyster (between 40 and 70 grammes) as preferred in South Africa and Europe, and about twice as long for the large oysters of between 90 and 250 grammes as favoured by the Asian market.
BASKET CASES Like most of its local competitors, Seafresh Investments uses baskets containing baby oysters called spat, suspended from rafts or ropes attached to drums floating on the surface of the ocean.
These baskets have to be extracted from the water and cleaned on a regular basis to remove algae growth which inhibits the free exchange of water and thus impedes the oxygen and nutrient supply to the oysters.
This is achieved using a vessel that navigates along the long rows of brightly coloured drums that are connected to each other with ropes and line the aqua park like oversized pearls on a necklace.
"Oyster production is a highly labour-intensive process", stresses West and elaborates: "Not only must we clean the baskets every month or so but we have to routinely remove the individual oysters, sort them according to size and place them back in bigger mesh bags or crates to accommodate for their rapid growth."
The positioning of the baskets is a matter of finding the right balance.
While the top layer of the ocean contains more oxygen beneficial to the growth of oysters, it is also characterised by increased water movement, caused by wind and waves.
This poses the risk of individual oysters colliding with each other and being slowed in their growth rate or damaged.
Generally oysters are highly susceptible to any changes to their environment, something Manuel Romero can attest to.
The Spanish national is the only scientist in Namibia producing oyster spat, using a laboratory in Walvis Bay.
"Until recently all oyster spat, which consists of larvae of about 12 mm, was imported from overseas, mostly from Chile," he explains.
Given the intricacies involved in generating spat, this hardly seems surprising.
"I've been experimenting for four years with various temperatures and nutrients as well as different methods in trying to prompt female oysters to spawn and generate larvae," recalls Romero.
"I still don't really know which set of circumstances they prefer or why they die under certain conditions that would theoretically appear conducive to them."
West agrees that oyster production is "a very difficult and complicated science" and that he and his colleagues still rely on trial and error to gain experience.
He concedes that currently the red tide phenomenon is the biggest challenge to the industry and ventures a suggestion to solve the problem.
"Oysters can survive for a matter of days on anaerobic respiration, meaning they close up and stop filtering water from outside," he explains.
Since red tides are usually brief, it should be theoretically possible to remove the baskets containing oysters during an algae bloom until the oceanic conditions normalise.
A different approach is the inland farming method, currently used by Walvis Bay Salt Refiners situated near the lagoon and the Salt Company, located 10 kilometres north of Swakopmund.
Here oysters are grown in inland ponds supplied with water from the ocean and giving the operators the opportunity to interrupt water supply from the sea in case of a red tide event.
But as the operations manager of Walvis Bay Salt Refiners, Stephan Anderson, notes, this is hardly an alternative for the besieged oyster industry.
"Oyster farming is just a sideline for us," he explains.
"The existing water canal through which we pump seawater from the ocean, as well as the pre-evaporation ponds of which some are used for oyster production, are necessary for our core business and thus freely available for oyster farming.
But it would probably not be financially viable for anybody to create these ponds solely for oyster production."
Irrespective of the uncertainty caused by the fear of red tides becoming a regular occurrence, Seafresh Investments has invested several million Namibian dollars in a new factory, which will become operational next month.
Seafresh will then be the first producer in Africa to export frozen half-shell oysters.
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