In the Seventies, Okinawa consumed 700 Ton+ of ‘Himejako’
An enormous amount of research was done in Giant Clam propagation and this farming activity is now supposed to be relatively easy, according to the South Pacific Commission. In Polynesia, Mother Nature has demonstrated that mass propagation of T.Maxima clams is happening even without a hatchery. So why are the 25 hatcheries in the Pacific unable to produce enough giant clams for the Asian markets?
The answer is surprisingly simple: these hatcheries have been unable to adapt the initial intensive Research techniques and comprehensive formal knowledge to their own field situation in a such a way that would be applicable to large extensive commercial projects.
Research entities are often poorly funded and have to take short cuts. As a result James Cook University in Townsville (JCU) and Micronesia Mariculture Demonstration Centre (MMDC), have always used low budget hardware like splasher pools, steel tanks with pool-liners, or concrete raceways to farm clams. These cost saving techniques have later been adopted by all new hatcheries with negative outcome, because this hardware is unsuitable to the stringent cleaning regime the juvenile clams have to undergo to survive the first few months. Juvenile clams grow extremely slowly at start and are easily overgrown by filamentous algae and/or Cyanobacteria before they are even visible. Unfortunately, a well known farming manual advises not to touch them for the first 2 months (CTSA no143, p19) and with this unilaterally adopted guideline, hatcheries still currently loose up to 98% of their early juvenile clams to the ‘myth’ that these are fragile.
Another error transferred with equally harmful consequences is the lack of aeration after a spawning (CTSA no130, p 47).
Phil’s own experience has convincingly demonstrated that a strong aeration is crucial for the first night to prevent the negatively buoyant eggs from sinking to the tank-bottom and die. Again, over 90% of the eggs can be lost that way.
Such cumulative heavy losses during 2 of the most important phases of the farming cycle have let the hatcheries to stagnate for 25 years, while easy solutions are readily available from people with common practical commercial shellfish farming experience.
At the end of their long project, JCU relocated 90,000 large T.Gigas to sites on the Great Barrier Reef; impressive for a research project and similar to what a commercial operation would produce in a much shorter time frame. In Palau, the MMDC was very active in clam farming promotion and training, still took years to accumulate a brood-stock of 10,000 T.Derasa. They send hundreds of thousands of clam-seeds to Pacific islands and even pioneered some market testing in Japan, also exceeding their objectives but their numbers were still short of seafood markets expectations as they were not commercially oriented.
On the other hand REEFARM, using fibreglass raceways and early intervention cleaning, in 1988 alone produced 1.6 million T.Crocea, which after a severe category 4 tropical Cyclone, “Joy”, were reduced to 100.000 clams, to be sold later on the German aquarium market for $10 each. The present price in Okinawa for fresh-in-shell Himejako is at least $2.50 per clam 8cm in size at around 3 years of age; this is quite similar to top-class products in the French edible oyster industry. Today France is producing more than 100.000 Ton/year of oysters worth over $ 500 M and employing close to 5000 farmers.
For Himejako (T.Crocea) to Japan the access to natural brood-stock is an essential criteria and farming sites must also be close to an international airport. However T.Gigas for China takes 10 years to grow to market size, can be harvested at sea and shipped in refrigerated containers, making this attractive to many more and even remote islands of the Indo-Pacific region. Centralised hatcheries to supply seeds for both Japanese and Chinese markets could be established in islands such as Yap in Micronesia, Coron in the Philippines, Western Solomon, Timor or Morotai in Indonesia and East-Timor to service their own regional suitable locations.
Can we now answer Phil’s question ‘Why not Giant Clams for Asia’? Multiple markets are starved of this exclusive seafood, farming methods are perfected, several good sites are available and willing; surely an opportunity like this should not be left aside any more. (lagoonclams)
References in the text:
Teitelbaum & Friedman: http://lagoonclams.com/
Other useful references: