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.

Raising fish in rice paddies brings to farmers in Asia an important source of protein, as well as extra income. Rice–Fish Culture in China is an important addition to the English language literature in this area. Along with biological and ecological aspects of rice–fish culture, this free online book (edited by Kenneth T. MacKay) addresses its economic and social dimensions.

From the preface and introduction:

A National Rice–Fish Farming Systems Symposium was held in China at the Freshwater Fisheries Research Centre of the Chinese Academy of Fisheries Sciences in Wuxi, Jiangsu Province, 4–8 October 1988. China has had a long history of rice–fish farming. As rural areas have been industrialized in recent years, rice–fish farming has gained attention because it is an organic method that combines rice and fish production while maximizing labour and ricefield resources.

Rice has always been the number one grain crop in China in terms of both area and yield. During the 1950s, the tradition of rice–fish farming developed substantially but the benefits were not significant. Fish harvests were poor because the method was based only on traditional experiences and technical difficulties were encountered. However, rice–fish farming developed rapidly and by 1988, 800 000 ha were being harvested with a average yield of 133 kg/ha. In some areas, yields exceeded 3750 kg/ha and many farmers harvested 15 000 kg of rice and 1500 kg of fish per hectare. The incomes of these farmers increased considerably. The techniques of rice–fish farming improved markedly as additional skill and experience were acquired.

Research was focused on the common needs of fish and rice for water, light, and nutrition under local conditions. Many new techniques were developed to suit various locations: ridge and ditch systems; semidry land; ditch manure pits; ditches with floating water; and rice–duckweed–fish systems.

Rice–fish farming is no longer limited to the household economy and to production for personal or family consumption. It is now part of farmland improvement, soil improvement, and environmental protection. Rice–fish farming has increased the productivity of ricefields and is fast becoming an important part of the commodity economy. It has also played a significant role in reforming the structure of rural industries.

Patrick Lavens and Patrick Sorgeloos, from the Laboratory of Aquaculture and Artemia Reference Center at the University of Ghent, in Belgium have edited a technical paper entitled Manual on the Production and Use of Live Food for Aquaculture. It is available as a free download.

The topics comprehensively covered include micro algae, rotifers, artemia, zooplankton, cladocerans (daphnia and moina), nematodes and trochophora larvae.

From the introduction:

Whereas in the 1970s the production of farmed marine finfish and shrimp relied almost exclusively on the capture of wild fry for subsequent stocking and on-growing in ponds, tanks or cages, the complete domestication of many marine and brackishwater aquaculture species was only achieved during the last two decades. However, since then the controlled production of larvae from captive broodstock, or in other words the hatchery production of fry, has now become a routine operation for most cultivated fish and shellfish species; billions of fish and shellfish larvae (i.e. bivalve molluscs, penaeid shrimp, salmonids, European seabass, Gilthead seabream etc.) currently being produced within hatcheries all over the world.

The cultivation of larvae is generally carried out under controlled hatchery conditions and usually requires specific culture techniques which are normally different from conventional nursery and grow-out procedures, and especially with respect to husbandry techniques, feeding strategies, and microbial control. The main reason for this is that the developing larvae are usually very small, extremely fragile, and generally not physiologically fully developed. For example, their small size (ie. small mouth size), the uncompleted development of their perception organs (ie. eyes, chemoreceptors) and digestive system, are limiting factors in proper feed selection and use during the early first-feeding or start-feeding period. Moreover, in species such as shrimp, these are not the only problems as the developing larvae also have to pass through different larval stages, eventually changing from a herbivorous filter feeding behaviour to a carnivorous hunting behaviour. It is perhaps not surprising therefore that larval nutrition, and in particular that of the sensitive first-feeding larvae, has become one of the major bottlenecks preventing the full commercialization of many farmed fish and shellfish species.

The Australian Rural Industries Research and Development Corporation has published The New Rural Industries – A handbook for Farmers and Investors. Of interest to prospective yabbie farmers and aquaculturalists in general is the chapter on yabbie farming. The web page does not include some of the graphics but the full document is available as a .pdf. From the introduction:

Yabbies (Cherax albidus and Cherax destructor) are indigenous to central and eastern Australia and have received considerable aquacultural interest. Although some yabbies are produced from ponds on purpose-built farms, the vast majority of commercial yabbie production in Australia comes from trapping in farmers’ dams what are essentially wild yabbies. This use of existing farm dams originally built to water stock has enabled rapid expansion of the industry because of the low entry cost. The yabbie industry currently harvests around 4000 farm dams in Western Australia. The rapid growth experienced by the industry is expected to continue, with processors reporting an increase this year of up to 400% in the number of farmers harvesting yabbies.

Australian yabbies are in demand internationally due to their high quality, larger size than crayfish produced by overseas competitors, acceptance by European markets as a replacement for diminishing stocks of their own native crayfish, freedom from major diseases and ability to be landed live in the major international markets.

Research has been undertaken to develop better performing varieties – often unmanaged populations become stunted because of overpopulation. Quantum – ABC Television reported in 1999 about the development of cross-breeding yabbies to produce all male offspring.

Dr Ian W Purvis of the Australian Government’s Rural Industries Research and Development Corporation has published Breeding Bigger Yabbies – Developing a genetically improved yabby to facilitate farm enterprise diversification. From the summary:

Aims of the Research
The objective of the research was to establish the best wild strains for aquaculture by discovering the heritability of desired characteristics, such as fast growth and large meaty tails. These strains were then selectively bred to develop a strain of yabby better suited to aquaculture.

Once such a yabby exists in an aquaculture environment, the yabby farmer can better control growth and quality of the livestock, important factors to maintaining a reliable and continuing market for this product.

Methods Used
Superior performing broodstock yabbies, from various geographic populations, identified by a strain comparison trial were combined to create a new “commercial” strain and subjected to four generations of within family selection. Faster growth was the primary selection goal. At the beginning of the trial the program was based on the evaluation of 100 full siblings from each of 30 families. Poor survival of three families reduced the total number in the program to 27. A control line consisting of randomly bred individuals from the 30 families was also maintained to allow assessments of genetic gain to be made through selective breeding.

Results
Of the four generations of selection, significant differences in mean liveweight at harvest were observed between select and control lines. The difference represented an average response to selection in both sexes of 12% per generation and a realized heritability for liveweight of 30%.

These results demonstrate that response to selection for liveweight in the yabby, Cherax destructor, can be successfully achieved. By selecting within families, significant gains were achieved in generations F2 and F3 that averaged around 15%. Coupled with the initial gains achieved by selecting the F1 founder generation, the select animals in generation F3 grew at 60-70 % faster than the average of all strains taken from the wild to initiate this study.

The full report is available as a .pdf.