aquaculture

Wasabi has been grown in Japan for hundreds of years. According to T. Sultana and G. Savage, of the Food Science department of Lincoln University, Christchurch, New Zealand, wasabi is now being grown in many countries in the world including New Zealand, Taiwan, Korea, Israel, Brazil, Thailand, Columbia, near Vancouver in Canada and Oregon, USA. The New Zealand Ministry of Agriculture and Fisheries introduced wasabi for experimental cultivation in 1982. It is widely accepted that the best wasabi is grown in running water. Water grown wasabi requires air temperatures ranging from 8 to 18^oC. However, a narrower range of temperatures (12 to 15^oC) is considered ideal. An air temperature of less than 8^oC inhibits plant growth and at less then 5^oC plant growth ceases. Other factors have an effect on the growth of wasabi and need to be considered carefully e.g stable water temperature, good nutrient status in water and well aerated, neutral or slightly acidic pH of water, high dissolved oxygen level in water and a large quantity of water flow.

Clearly, conditions not easily reproduced in a typical aquacultural environment. The requirements for the commercial production of top grade wasabi has been mastered by New Zealand Wasabi Ltd, owned and operated by Jenny and Michel Van Mellaerts in Warkworth, north of Auckland, New Zealand. Michel kindly agreed to the following interview:

Lynsey: The first question – why wasabi? It’s a pioneering crop, there are other crops well documented, and in the north of New Zealand the options are broad in terms of what crops could be grown.

Michel: That actually is a very good question. Sometimes, we ask ourselves the same thing. Initially when we bought our first lifestyle block (5 acres), it had a nashi pear orchard. However, the bottom had just fallen out of that market and the idea of working like dogs picking the pears for no return did not really appeal – little did we know: . Anyway, we started looking around for something that we could grow, hopefully wouldn’t involve a massive amount of ongoing work, and gave a decent return. Well, at least enough to pay the mortgage.

It was quite by chance we stumbled across wasabi. We had been to the beach, and on coming home one evening flicked on the television and it was at the end of a “Country Calendar” program, where they were showing a paddock of wasabi being trailed down in Canterbury [in the South Island]. They mentioned the name and that it was worth $100 a kilo. It was this that piqued our interest. After all – that was a decent return AND it was legal . We then started to try and find out about this crop. What we found was not very encouraging.

The information that was available was basically a load of rubbish. Nowhere was there a definitive guide for wasabi growing. There were descriptions of places where wasabi was being grown. This was mainly descriptions of modified streambeds in Japan with the occasional mention of soil grown product. There were a couple of wasabi “experts” in New Zealand that we dealt with at length until it became apparent that their expertise was based on what they read (same stuff as us), and a couple of visits to Japan at the ratepayers expense. However, they did have some plant material that we could purchase to carry out trials.

At that point, Jenny and I had to make a decision. Did we jump over the cliff into the unknown or did we find something easier? You have to remember that at that point in time the only successful growers that we knew of were in Japan, and they were not sharing information (they still don’t). Anyway, both being naive, we decided to try a few plants. After all, we reckoned, they were only plants and if they could grow them in the South Island, then it couldn’t be too difficult. After losing a number of crops by following the “experts” advice, we got rid of them all (the experts) and started using our own ideas. Eventually, after a few years (and lots of dead plants), we finally figured out what we need to do to produce the best water grown wasabi in the world.

On a trip to Japan to talk to people at the Wasabi growing laboratories that they have in certain areas of Japan, we were told that they had trialed growing wasabi hydroponically, and because they were unsuccessful then it obviously wasn’t possible. They also were reluctant to even give the basic growing information to us. We eventually figured this out by trial and error and listening very carefully. We found it amazing that the collection of a lot of throw away remarks that these people used to show us how clever they were crystallised into firm, accurate information.

As an engineer we decided that we would ignore all the information that we had collected to date (99% of it was misinformation and still is), and we sat down and determined what we believed we needed to do to get wasabi to grow properly. We designed and built a growing system, which today is still the basis of our success, and started growing the best wasabi in the world. We have not stopped since that time

So as you can see, the simple answer to your question is that we were too dumb to realise that wasabi could not be grown in New Zealand using hydroponic methods.

Lynsey: What experiences in your background has prepared you both for wasabi farming?

Michel: In terms of full on, dirty handed farming – nothing. I was vice president of Soil & Health New Zealand for a couple of years and had been growing vegetables organically (domestically) for 20 years or so before this venture. Apart from that, neither of us had any idea what we were getting into.

However, as entrepreneurs we excelled. We had the first privately owned CAD system in New Zealand. We used that to set up a CAD consultancy and training company. We eventually sold that when we had trained enough university staff so that they could claim to be “experts” and started pinching clients. We also brought to New Zealand the first fully integrated accounting software package that we sold countrywide. A couple of other engineering consultancy based projects were brought to fruition and sold off when the market started to flatten. I have a number of degrees in Engineering, Physics, and an MBA. All of these have been used to get to where we are today. Jenny has Ph.D. degrees in loving, encouragement, enthusiasm and determination. I think she has the best qualifications.

The wasabi project has been the longest running one for us. It is also the one that has brought the most satisfaction. Single handedly we have built and developed the New Zealand wasabi industry without any outside help or finance. We are now the biggest growers, processors, and marketers of Wasabia japonica products in the Southern Hemisphere and are now expanding into the Northern Hemisphere. We started the first commercial website in New Zealand, and were told at the time that the Internet was merely a flash in the pan. We back ourselves. Sure we have made mistakes that have cost us a lot of money, but we have learnt as we have gone along. We have cut a path through the wilderness and now others are following.

Part two continues…>>

Disclaimer: I have no association with New Zealand Wasabi Ltd.

R A Leng, J H Stambolie, and R Bell from the Centre for Duckweed Research and Development at the University of New England Armidale, New South Wales, Australia; have published a research report on the potential of duckweed as a high-protein feed resource for domestic animals and fish.

From the summary:

Duckweeds have received research attention because of their great potential to remove mineral contaminants from waste waters emanating from sewage works, intensive animal industries or from intensive irrigated crop production. Duckweeds need to be managed, protected from wind, maintained at an optimum density by judicious and regular harvesting and fertilised to balance nutrient concentrations in water to obtain optimal growth rates. When effectively managed in this way duckweeds yield 10-30 ton DM/ha/year containing up to 43% crude protein, 5% lipids and a highly digestible dry matter.

Duckweeds have been fed to animals and fish to complement diets, largely to provide a protein of high biological value. Fish production can be stimulated by feeding duckweed to the extent that yields can be increased from a few hundred kilograms per hectare/year to 10 tonnes/ha/year.

Mature poultry can utilise duckweed as a substitute for vegetable protein in cereal grain based diets whereas very young chickens suffered a small weight gain reduction by such substitution. Pigs can use duckweed as a protein/energy source with slightly less efficiency than soyabean meal.

Little work has been done on duckweed meals as supplements to forages given to ruminants, but there appears to be considerable scope for its use as a mineral (particularly P) and N source. The protein of duckweeds requires treatment to protect it from microbial degradation in the rumen in order to provide protein directly to the animal.

The combination of crop residues and fresh duckweeds in a diet for ruminants appears to provide a balance of nutrients capable of optimising rumen microbial fermentative capacity. These diets can, therefore, be potentially exploited in cattle, sheep and goat production systems particularly by small farmers in tropical developing countries.

Paul Adler examines young lettuce seedlings which are grown for about 3 weeks in a separate hydroponic system before they are set in the “conveyor production system” to remove nutrients from the rainbow trout effluent. (Photo by Keith Weller, USDA-ARS).

Adler, P.R. 1998. Phytoremediation of aquaculture effluents. Aquaponics J. 4(4):10-15. From the abstract:

The study is on an integrated system for rainbow trout production, effluent treatment and production of lettuce. The objective was to reuse water by removal of the nutrients in a vegetable product. The microscreen filter removes about 80% of the P excreted by the fish with the biosolids, leaving about 20% of the P in the effluent. A mass balance of system nutrients was conducted and it was determined that it takes 7.5 – 10 heads of lettuce to remove the P excreted in the effluent by the production of 1 pound of trout or 13 – 18 lettuce heads for each kg of feed consumed. Greenhouse studies demonstrated that by using the conveyor production strategy (CPS), phosphorus could be removed to <0.01 mg/L by lettuce without an apparent reduction in production or quality.

Conventional thinking regarding the use of food crops to clean aquaculture effluents has been that plants cannot remove nutrients in water to low levels without a reduction in productivity and quality. If water is distributed in a horizontal plug-flow pattern, all nutrients will be luxury consumed at the inlet, making nutrients limiting at the outlet and significant greenhouse space will be dedicated to growing plants that have no market value.

Because greenhouse space is expensive, productivity is critical for a profitable operation. A unique production system for lettuce, called the conveyor production strategy (CPS), was developed using thin-film technology for plant production in dilute aquaculture effluents. With the CPS, young plants are positioned near the solution inlet and are moved progressively, like along a conveyor belt, towards the outlet as they grow. Luxury consumption by lettuce (Lactuca sativa L.cv. Ostinata) enabled them to store P in their tissues early in their growth cycle for use later as water P levels decreased and influx could no longer meet current demands.