THA: 75/008/80/WP/14
BAY BRAND ARTEMIA
(AN ACCOUNT OF A 1971 VISIT TO SAN FRANCISCO)
(AN ACCOUNT OF A 1971 VISIT TO SAN FRANCISCO)
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THA: 75/008/80/WP/14
BAY BRAND ARTEMIA (AN ACCOUNT OF A 1971 VISIT TO SAN FRANCISCO) |
by
Michael B. New
National Freshwater Prawn Research and Training Centre
Inland Fisheries Division, Department of Fisheries
Ministry of Agriculture and Cooperatives
(FAO/UNDP/THA/75/008)
Bangpakong, Chacheongsao
Thailand
1980
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by
Michael B. New, Senior Fisheries Biologist (Aquaculture)
UNDP/FAO Project THA/75/008
Chacheongsao Fisheries Station
Bangpakong, Chacheongsao, Thailand
The following notes were produced from a verbatim account of an interview with the Technical Director of “Bay Brand” in San Francisco on 15 March 1971. The company was then known as California Brine Shrimp Inc.
While the notes are based on the techniques employed by the company 9 years ago, and therefore inevitably out of date, it is felt that they may nevertheless make interesting reading for those currently engaged in cyst production. If some of the comments I made in 1971 seem a little strange, please remember that you, the reader, have the advantage of 9 further years of research and development in this field.
Acknowledgements are due to Ranks Hovis McDougall Ltd., England, who were my employers in 1971 and who financed the tour of which this visit was a part.
Since 1969 this has been a subsidiary of Metaframe Corporation which makes aquarium supplies in America, which in turn is a division of Mettel Inc. I met Mr. Seymour (Cy) Bergen who is the Vice President of the Metaframe Corporation but I spent most of the time with Mr. Irving G. Fishman who is Technical Director. Mr. Zorbas is no longer with the firm. The present Managing Director is Mr. Anton Schmidt.
Most of their business is in selling live Artemia which they simply fish out of the salt ponds there and also in selling frozen full size Artemia, and also freeze dried. They are doing some experimental work on hatching the eggs so that they can freeze the day-old nauplii for sale.
They have sole right to harvest Artemia from the private ponds belonging to the Lesley Salt Company which has some 20 000 ha of salt ponds. It is the largest solar evaporation plant in the world. They said that obviously, there were a finite number of eggs available but when pressed they thought that, given a demand, they could exploit the ponds very much more than they do now. There are many areas of the bay which they do not use at all and many automated techniques of collection which they have not found necessary to use so far.
He says there are many different species of Artemia. Their particular version is diploid and bisexual. They give birth live and also lay eggs depending on environmental conditions. For example in Moa Lake in the Sierras, no one has ever found any eggs. They seem to have to be dessicated before they will hatch. The San Francisco type tends to be a bit smaller than the Utah. The average size is 190 to 200 microns, whereas the Utah is over 200 microns. The Utah one is also heavier, and a full can can weigh up to 20% more than the San Francisco type. The Utah shells are thicker and therefore harder to hatch and need extremely vigorous aeration to hatch them. They reckon their San Francisco variety is better because of the ease of hatching, its small size, and the lack of DDT problems. DDT is now banned in California so they have no DDT in the Bay, in fact the Bay is no longer monitored for DDT because levels got so low.
The “Leslie” Salt Process involves taking Bay water into the first pond where the water is about 27 ppt. and then they have to gravity or pump flow from one pond to another. They allow a certain amount of evaporation to take place in one pond and then they pump it into the next and so on. It takes about 3 to 5 years to go right round the cycle. Then they drop the water into evaporators when it starts to precipitate out, and they have 3 separate lots of evaporators in different parts of the Bay. They also get a certain amount of dilution from rain water in the ponds at certain times and it is this which causes the Artemia to hatch out. They are also able to dilute their pond water with fresh Bay water at certain points. It is necessary to be able to do this so that you can keep the flow moving. Therefore their system is not a salt pond, it's what they call a saltern. There is a very small tidal flow in the area.
They harvest eggs from any of the ponds, where there are no live fish, anywhere above the salinity at which the eggs will not hatch. At this point it is probably 3 to 4 times the strength of seawater, almost at saturation. At lower salinities they bear live offspring. They often detect both the presence of live Artemia and eggs from the air (by plane). They would not really conjecture what the potential supply might be, but they said that in the last season they have been doing the best they ever have done. Most of the trade is in live and frozen Artemia. Eggs are a fairly small part. There are 2 quite different hunting operations, one is for live Artemia and one is for eggs. They would naturally, of course, prefer to see a growth in the market for the “number ten” can type of eggs.
He thinks it is best to keep the eggs in a freezer. He says that you cannot damage them by taking them down to too low a temperature and it is best to keep the cans completely sealed to avoid moisture. When you do have to open a large can it is best to open up the smallest type of hole you can and pour the eggs out and seal the hole with scotch tape. It is important to keep them cool and particularly to keep them away from any humidity. But if possible to keep them in vacuum. He suggested that we might break the cans up into smaller ones and re-pack them with vacuum, and that we should not keep them over a year because hatchability is likely to decline after that time.
He said that their sales of other products were $5 million last year, and that the price we are paying for eggs is a particularly cheap price for research organisations (i). They have plenty of spare ponds which have now been created a wild life conservation area where only salting can take place. This means they have much more control over their harvesting areas than anybody else working with Artemia in the world has. So they feel pretty confident that they can provide whatever the world demands. They used to perennially have a shortage from January to March but in the first year that they took over they cured this problem by stock piling.
The size of the San Francisco eggs is 0.2 mm average whereas the Utah average is 0.21555 mm which represents about 26% larger volume. He says that the hatching rate should be more than 80%, more like 85%, which he thinks is just about the maximum. At the moment they are selling 6 000 cans a season. I saw the way in which they harvest the live Artemia, which is an extraordinary contraption of which I had a slide (now property of RHM Ltd.). They were just moving an outboard motor-driven scoop along the pond and scooping the Artemia into a net and from there ‘dip-netting’ into buckets. I also quickly saw how they treat their raw eggs as they come in. The eggs are harvested by hand net and put into hessian sacks where they are hung to dry out. Apparently the humidity is reasonably low. In an open-door galvanised shed they hung the sacks along rows of wooden posts. They can remain there for up a year, then the contents of the sacks are tipped out into a circular series of vibrating screens and washed with fresh water. I had a photograph of this operation. What happens then is that the debris which consists of a number of different materials, including feathers, separates out on the top, the eggs and the smaller debris goes through the first screen which is 250 u. Then the eggs are retained by 100 u mesh underneath, and the rest washes through. They then spin the eggs dry in a very crude apparatus, a domestic spin dryer, and this loses about 10% of the moisture. Then they take them upstairs for final drying. A certain amount of development takes place in the eggs while they are actually washing them in fresh water. And this is the reason why you get different size nauplii from eggs. They try and cut this process down to an absolute minimum. They hold the live nauplii at 1.050 special gravity. Eggs are held in sacks for months before washing and temperature does not seem to matter at this stage.
The live Artemia that I saw were very large any “probably over 21 days old” and they use very vigorous aeration in these maintenance tanks.
When the eggs go upstairs for further drying they lay them on a cloth screen in trays, this cloth is unbleached muslin, and they dry at 110°F overnight. This brings them from 50% moisture down to 2–3% moisture. They then screen them again which breaks up the crumbs, on a vibratory screen, and sorts the feathers and threads etc., out. They then hold in 100 lb. cases first and they sample these at intervals with a grain sampler. They used to use a tumble dryer but they do not use this anymore. After this they distribute them into cans, seal the cans and leave a small hole and evacuate them and seal, but they are installing new machinery which will do the canning process and evacuate at the same time without having to seal this single hole.
As far as quality control goes, they do hatching tests using equipment rather like the hobby aquarist would. They do this test at 80°F placing the eggs on the surface and allowing the nauplii to swim under a weir, and they compare a known volume of eggs to a known hatch. They also do a moisture control and weight test. The volume/weight ratio should be about 50% in other words 0.5g. should have a volume of 1 cc. They keep in 100 lb. sacks for less than one month. The canner they are using now is a very simple one. Their average figures are 250 000/g of the San Francisco and 200 000/g of the Utah, which means there are about 310 000 000 eggs per can of the San Francisco one (that is in 1 250 grammes).
I then went and looked at one of the salt pans, which was 162 ha pond and I had some colour shots of that. They are also growing Artemia in buckets in order to freeze 24 hour old nauplii. This is in the experimental stage. They are using very thin PVC piping for aerators with a threaded saddle to fit a shaped brass air fitting. I noticed they were using gas air heaters in that room. The live brine shrimp that they fish out of the ponds are kept in a number of holding tanks, in vigorously aerated 5% salt solution (?) + 5 ppt. (0.5%) of Epsom salts. This means that they are then kept in clean water ready for despatch and are sent out in another portion of the same liquid.
