Three alternatives for marron farming water outlets

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chemical safety and alert from curtin university http://healthandsafety.curtin.edu.au/hazardous_substances/chemicals.cfm

chemical safety and alert from curtin university http://healthandsafety.curtin.edu.au/hazardous_substances/chemicals.cfm

Manual of Marron Farming

Table of Content 1 1. Introduction 3 2. Biology of Marron 4 3. Farming Marron 6 3.1. Site Selection 7 3.2. Pond design and construction 9 4. Farm operation maintenance 13 4.1. Improving water quality 13 4.2. Feeding 15 4.3. Shelters 16 4.4. Potection from predator 17 5. Harvesting 18 Bibliography 20 Appendixes 21 1. Introduction Australia has a large varieties of freshwater crayfish species known as members of family Parasticidae. From up to 100 species found and identified, three species have been cultured and potentially become aquaculture commodities of this country. These species are Marron (Cherax tenuimanus), Yabbie (Cherax destructor) and Red Claw (Cherax quadricarinatus). Among these species, marron has the largest maximum size and have been cultured since 1970s. However, the understanding of its culture techniques is still being developed. As a third largest freshwater crayfish in the world, after Tasmanian crayfish (Ascatopsis goudi) and Murray crayfish (Eustacus armatus), a marron can reach the maximum size of two kilograms with 38 cm in length . The word marron refer to French word which mean water chest nut, but other opinion said that the word marron refer to an aboriginal word means food. In recent years, compared to other commodities, marron farming has the most farms in Western Australia aquaculture industries. Trend production from 1999 to 2008 reach its peak in 2006, where there were 178 farmers producing more than 60 tonnes a year of marron with the value around $ AUD 1.6 million. Marrons farming also have been practised in South parts of Australia. It has been introduced to Kangaroo island in 1960s but the farming activity was growing faster during early of 1990s. Nowadays, many experiment are still being done to improve techniques of marron farming by several trials and research on their biology, physiology, nutrition, culture system, diseases and post harvesting stage. Marron farming mostly done in earthen ponds by utilising water from surface area including run-off, dams and swamps. This venture is widely used because it enables farmers to control the culture environment, in order to get a certain amount of marron production. Normally, a unit of marron farming will have ponds with several purposes such as grow-out ponds, spawning/ mating ponds, nursing ponds and a supply dams functioned as water reserve ponds. To improve water quality, a good construction of ponds is required, pre-treatment of ponds by liming and aeration during grow out is supplied by mechanical aerator or paddle wheels. Feeding is given daily every night and once they reach size for human consumption, harvesting can be done either by netting or draining the ponds by gravitation. Prize per kilogram is increases by size and because marron can survive without water for several days, normally, this species is traded as a live product. In order to establish and operate marron farming, many aspects need to be considered. This manual aims to provide a practical guide to do marron farming in ponds by compiling information from text books, research papers, lecture materials, websites, pamphlets and short articles from varied sources. Information given includes biology of marron, site selection, ponds management, feeding, harvesting and a brief information about transporting marron as live product. 2. Biology of Marron Marron (Cherax tenuimanus) is a species from Family Parastacidae known as Australian freshwater crayfish which is consist of nine genera. Among all the species in the genus of Cherax, marron is the species that can grow largest (up to 38 cm in total length). The head has five ridges, including the spiny rostrum (figure 1). While the first pair of clawed legs are pincer-like and narrower compared to Yabbie and Koonac. Tail has two small spines on the central segment of the fan which is their specific character to differ them to other freshwater crayfish from Western Australia (figure 1). The colour usually dark brown at larger sizes, but when young can be varied from brown, dark blue or even red and blue. Dark coloration of marron can protect them from predator as water of their natural habitat contain high tannins concentration, which make the colour of water become brown. Figure 1. top view of Marron (Cherax tenuimanus). Marron is an endemic species from south-west areas of Western Australia where the rainfall is high and the mean of annual temperatures is lower compared to other regions in Western Australia. In this area, marron with smooth carapaces is more abundant than hairy marron, which is mostly found in Margaret River. In nature, marron distribution now has been extended from stream near Esperance to as far north as a stream near Geraldton. Because of International interest as aquaculture commodity, this species also has been introduced to some foreign countries such as South Africa, Zimbabwe, Japan, USA, China and the Caribbean. In their nature habitat, marrons occupy permanent rivers and streams but different with yabbies and red claws, they don’t burrow to escape drought when summer comes. Marrons occur in water which has pH levels ranging between 7.0 to 8.5 and can tolerate salinity from freshwater to 15 ppt. However, they grow best in lower salinity as their growth will be reduced at salinity more than 6 ppt. Marron is a nocturnal species and most active just after sunset. During the day, they hide in shelters such as rocks or fallen logs. As the member of ecosystem in freshwater area, marrons play role as scavengers, where they fed on detritus, dead animal, insects, worm and plants. Beside that important role, marrons are also prey for birds and mammals. As an adaptation to freshwater life, Family Parastacidae including marron have shortened life cycles compared to marine lobsters and Penaids. They have relatively larger eggs and hatch as juvenile crayfish, not as planktonic larvae as in most crustaceans. As seasonal breeding species, they usually mate in early spring and females usually incubates 450 – 900 eggs. Eggs and hatched larvae stay for 12 to 16 weeks on females’ pleopods until they become juvenile in early summer and leave their parent. Females with eggs or larvae attached are known as ‘berried females’. Marron sexes can be distinguished by the presence of gonophores on the bases of the fifth pairs of legs, indicating the male of marron while the female has pores on the third pair of legs. Figure 2. Morphological difference of male and female marron. 3. Farming Marron There are two distinct types of marron culture based on marron ages and size. Firstly is hatchery, where juveniles are produced and secondly grow-out operation, which is stocking marron until they reach sizes for human consumption. Practically, these two type of cultures usually can be combined and worked together by a farmer as marron can be spawn naturally without hi- technology modifications on culture area. Generally, hatchery operation can have profit faster than grow out system due to the lower investment of capital cost since a hatchery does not require a land as large as grow- out operation and less feeding are given. However, maintenance in this operation is more intense and require skill full operators. Mainly, the activities in hatchery include stocking and mating the broodstocks, followed by rearing larvae to juvenile size. In grow-out operations, marron farming can be classified to extensive, semi intensive and intensive system. An extensive system utilizes dams or flooded area to stock marron with mixed-aged group and harvesting is done by using traps. This system does not require management to water quality, predator control and artificial feeds, which makes the capital cost to produce marron is the least among two other systems. However, mortality in this type is high, makes its annual production low. In contrary, an intensive farming system applies full control over culture areas and the marron. Usually, marrons are kept in a battery system, single compartment to prevent cannibalism when moulting occurred and clean water is continuously supplied by a recirculating aquatic system. A resume of these three systems can is shown on table 1. Even this system offers a very high production and survival rate for the marron, the capital cost from maintaining the system is also very high, makes it still only viable on research purposes. This system also require a very good formulated diet for marron, base on nutritional contents and water stability, which is still being developed until now. Table 1. Different types analysis of marron farming by David O’ Sullivan (1990). Classification Extensive Semi intensive Intensive (battery) Pond type Farm dam Earthen ponds Tank, race way Stocking density (juveniles) 1 per m2 7 -10 per m2 50 – 100 per m3 Water quality No control Pumps, aeration Strict control Feeding Natural Natural and pellets Formulated pellets Predator Control None Fences, netting Indoor culture Annual production (kg/ha) < 400 2,000 -3,000 > 10,000 Semi intensive system using earthen ponds is the most popular way to produce marron at this moment. This system has been proven to be economically feasible and have a higher annual production rates compared to extensive system. Basically, marrons are kept in a closed area with feeding given regularly and water can be managed by the farmers, depend on certain purposes of farming activities. This manual specifically will focus on marron culture using ponds. 3.1. Site Selection Several factors need to be considered on planning for marron culture in ponds such as water sources, geographic location and the characteristic of soils in proposed areas. Other non-technical factors like obtaining license, local laws, fund availability, security and market should also not to be ignored as the success of a marron farm will depend on how farmers to integrate their resources while solving technical and non-technical issues on their production period. It is also important to think about the scale of marron farm before making a decision to start the operation. This will related with the future development of a venture where there is always a possibility of farming area extensions. In selecting site, water is the first factor to consider. This should be seen from both quantity and its quality. Water can be obtained from several sources of surface water such as dams, river, creeks, run-off, swamps and bore water. Different source has their own features. Bore water can provide a clean, pest free and pristine water, but the cost of pumping will increase capital cost. In certain places, bore water may contain saline water which will harm and reduce marron growth rates. Meanwhile, water from surface areas can be very cheap and easy to be obtained even with some risk of pest introduction (fish) and possibility of pollution from agriculture activities. Finally, decision to choose source of water should be made base on calculation and cost to stock and manage water for a long term. Figure 3. A natural dam as water source of marron farming in Denmark, south-west of Western Australia. Providing water reserve/dams is a must as water loss from evaporation and leakages are unavoidable. Ideally, farmers should know how much annual budget of their water usages to allocate an exact proportion of areas to stock water that will be used for grow-out operation functioned as a reserves. Summer time in Australia can be very dry and caused a huge loss of water from pond surfaces by evaporation. Beside reducing water volume inside the ponds, a wide range difference on temperatures outside and inside the water may occurs and leads to water temperature stratification and finally triggers oxygen depletion in the bottom area inside the ponds which will disturb marron growth or even increasing their mortality. Several water quality parameters in surrounding proposed area should be checked. A complete recommended water analysis from Fisheries Department of Western Australia includes pH, conductivity, total dissolved solid, cation (sodium, potassium, calcium and magnesium), anion(chloride, bicarbonate, carbonate and sulphate), heavy metals (copper, iron and zinc), toxic metabolites (hydrogen sulphide, TAN, nitrite and nitrate), turbidity, productivity ( total hardness and alkalinity), gases (dissolved oxygen and ammonia) and pesticide in the water and soil (DDT and dieldrin). Another simple hint is to see any bio-indicator surrounding the proposed area, whether any crayfish available, especially marron can be found nearby the area, which indicates the area has potentials to be used for farming operation. Geographic location is a factor that can dictate what kind of commodities that suitable to be farmed in certain area. This factor related with annual temperature, which is a factor that can limit and determine the welfare of farmed animal. South-west region of west Australia is the best place to culture marron, as this region provides an relatively lower temperature than other places in the state. Marron cannot withstand a temperature above 30oC and their optimum level for growth should be maintained in the range from 20 to 24oC. There is a story in 1980s where marron had been introduced to Queensland, by the optimism that they will grow faster in warmer region than in their original habitat. A large fund had been invested for farming this exotic species but the result was surprisingly different. Because of higher temperatures, they grew slowly and even the mortality was very high, forcing the venture to change their farmed species to red claw to save the big investment.   3.2. Pond design and construction Design and construction play an important role in the ease of farming operation. These design and construction including the lay out/plan of the whole farm area, pond walls, pond floors, inlet and outlet designs and other facilities or building such as a workshop, feed storage and farmer housing that located within the farm. Generally, designing a farm and its ponds should refers to farming activities within the farm, which sometimes require an easy access to every spots of the farm. Meanwhile, stronger construction when possible is better, but it always related with the capital cost of building the farm. Master plan and lay out of the farm should be made and communicated to builders before building the farms. In some cases where the area is very large, it is important to allocate some spaces to allow the development of farm in the future. Basically, some component within the farm that should be included are ponds (grow out ponds, nursing ponds, settlement ponds and water reserve ponds), drainage system, inlet system, fences and a work shop where farmers stock marron feeds. In some cases, a house for farm operator should be provided within the area if the farm needs to be monitored every day. If there is a possibility of moving the water by gravitation, water reserve ponds should be placed in higher area, followed by nursing and grow out ponds, settlement ponds and drainage system. Usually, pond shape is rectangular, with the inlet direction facing prevailing wind direction. Size of the ponds should be manageable. In practical, four or five ponds in a hectare are considered as cost efficient. Some farmers suggest the size of 20 x 50 m with depth around 0.8 to 1.5 m for grow out purposes. Depth is related with the availability of plankton that can be provided by the ponds. In nursing ponds, it can be more shallow than grow out ponds to allow sun light penetration to the bottom of the ponds, which will make plankton grow better. Ponds for nursing purposes can use the same size of ponds, but preferably smaller to make maintenance and harvesting easier. Bank and floor of pond should be stable and able to store water with minimum leaks. Pond banks and floor are constructed using soil in the farm area. To prevent leaks and improve stability, pond banks should be compacted and mixed with lime stone and gravel . in a very porous area and the risk of leaks is high, farmers can also mixed the soil with bentonite at the time of construction. Bentonite is a powdered material which swells when wet and able to close off leaks. This material can be obtained from local product stores. Banks or pond walls for marron farming is designed with 1 : 2,5 to 1 : 3 elevation. This elevation will provide a stable and prevent wall erosion. It also provides easy access for farmers to get into ponds and feeding spaces for marron. The illustration for elevation of pond is shown on figure 2. A basin with 10 -20 cm depth in ponds floor should be constructed by concrete material. This basin function as a collecting area when harvesting marron and very useful to collect sludge after a cycle of grow out operation finished. Figure 4. Suggested elevation for marron ponds. Since marron ponds usually classified as stagnant ponds, where water circulation is operated when it is needed, a large diameter of hose can be used as water inlet to the ponds. However, an inlet design using PVC pipes which are installed to all the ponds can provide more easier and practical way to move water from water reserve ponds. Basically, for inlet and outlet pipes, larger diameter of pipes will work better since it can remove water faster than the smaller one. Although the cost for larger pipe diameter is usually higher, investing in this component will save time on filling and discharging water. Because marron is sensitive to high temperatures, a caution should be made when draining a pond for harvesting or shorting. Ponds should be emptied as soon as possible in the morning to prevent temperature rising in the water which can cause high mortality of the marron. Beside its basic function to drain water inside the ponds, water outlet can be used to regulate the water depth within the ponds. Some construction to allow this function is illustrated in figure 5. A monk design, which is adopted from the outlet of penaid prawn ponds is very suggested to be used because its ability to discharge water in the bottom of the ponds and regulate the water depth (figure 6). In some area, discharging water from ponds to natural environment is highly prohibited by law. Settlement ponds with varied water plants can be used to absorb and neutralize the waste from culture area. This settlement pond should be positioned and connected to ditches within the farm. Figure 5. Three alternatives of ponds out lets in marron farm. A and C are considered safer than B because water depth regulations are better constructed. Figure 6. Monk outlet (type C), is adopted from outlet ponds in penaid prawn in Asia. Water depth can be adjusted by placing boards (shown in blue colour)in desired depth. A modification to put nets in the front parts is needed to prevent marron escape from grow-out ponds. Figure 7. Ditches for drainage in marron ponds. Note the height different between the ditches and ponds on left side that can allow draining by gravitation. 4. Farm operation maintenance Maintenance in grow-out operation includes several activities that support and ensure the success of marron farming. These activities are improving water quality, feeding, protection to predators, harvesting and post harvesting activities. 4.1. Improving water quality Maintaining water quality parameters in optimum level for marron is very important. Mainly, temperature and oxygen are factors that limit marron production in a pond. Other parameters that should be monitored are pH, hardness and ammonia. To achieve a larger yield in ponds, farmers should stock marron in a higher density compared to extensive system or marron stock density in nature. In order to compensate this high stocking, improvement on water quality should be done by applying several equipments to increase dissolved oxygen in the water. Water quality requirement for marron farming is shown in table 2. Table 2. Water quality requirements in marron farming. Parameters Range Oxygen : > 3 ppm pH : 7.5 – 8.5 Hardness : 50 – 300 mg/l Ammonia : < 0.25 ppm Temperature : 17 – 25 oC Salinity : < 3 ppt Regular water quality tests should be conducted to know and maintain the water in good condition. This can be done by several relatively inexpensive tools which are available in analytical supply stores. Usually, these tools use digital reading to show the value of water quality and some simple chemical test kits. Aeration is needed to increase dissolved oxygen and circulate the water around the ponds. In semi-intensive ponds, having a high stock will be followed by higher feeding and higher metabolism of marrons. Finally, the result of these activities will result more wastes that bring bad impacts to water quality, especially by the presence of carbon dioxide and nitrogen gases in the form of ammonia, nitrite and nitrate. Especially for species like marron that inhabit bottom area of ponds, the presence of this gases could be fatal and cause high mortality. By applying aerations to ponds, nitrogen gases can be lifted from the water, especially bottom area and release to the air. Figure 8. Daily water quality checking is one of the important activities in semi- intensive marron farm. Basic principle of aeration is performed by adding oxygen directly to the water, mixing and circulate the water inside the ponds. Several methods can be applied by the addition of paddle wheels, submersible pumps and diffusing oxygen using blower/hi-blower. Paddle wheels is the most widely used for marron grow-out ponds. Compared to other methods, it improve oxygen and circulation faster as it can destratifies oxygen and temperature in a pond through strong water circulation and increase large surface area of water-air interface by spraying water into the air. Another advantage is paddle wheels only need to be operated for one hour, three times per day to increase the oxygen in its lowest period (usually in late afternoon, late evening and dawn/before sunrise), which is more cost efficient than submersible water pumps and aeration through blower that is operated 24 hours per day. However, farmers in South Australia prefer to use pumps system to aerate their ponds because it is easier to construct and relatively cheaper than paddle wheels. Figure 9. Paddle wheel is used to improve and circulate dissolved oxygen in the water, allowing farmers to increase marron stock density . 4.2. Feeding In semi intensive ponds, farmers use formulated pellet to boost marron growth. In the beginning of stocking, feeding is usually combined with the presence of plankton and natural food in the ponds. As they are growing bigger, some farmers use lupins as additional feed. In order to suit marron’s nocturnal character, feeding should be given at night. Two methods has been used to determine feeding quantity for marron. The first method use body weight basis to calculate the feeding amounts for marron. Common percentage is 3 % of body weight and feeds are given daily. the total amount is expressed by gram per square metre per week (g/m2/week) which is devided into 7 days to get the daily feed amount. Body weight values are obtained by taking several marrons as a sample and define their mean weight. The second method known as maximum feeding is basically adopted from penaid prawn culture where feeding rate is calculated by sampling the feeding rate of the biomass per square metre. This method is believed to give more accurate feeding amount than body weight basis as the first method usually fails to give correct value of daily weight gain. In this method, feeds are spread around the edges of ponds at sunset and the edges are examined on the next day for uneaten feed. In turbid water, a 1 m2 drop net with small mesh size can be used to examined uneaten feeds. Usually, feeding rates is influenced by temperatures and 5 gram feed/m2 adjustment is commonly applied in this method. An experienced farm operator can determine to add or reduce feeding amount by seeing the result of sampling in certain times. Figure 10. An example of formulated diet for Marron from Westfeeds company which contains 22 % of protein from animal and plants sources. 4.3. Shelters Providing shelters also play an important role in marron farming. Shelter is a must in crayfish culture due to their moulting habit (ecdysis). During ecdysis period, marron will release their old exoskeleton/hard shell and replaced it with the new one in order to get bigger on their body size. This period can be very critical to their lives since they will inactive and the new exoskeleton still very soft in a short time while their body also excrete pheromone, which can attract other marron to come and make them extremely prone to cannibalism. Providing shelters also mimics their habit in the nature as they usually hide and inactive during the day. Shelter can be made from plastic, nets or even PVC. Basic consideration of shelter material is use materials that can provide them a space to hide while the material will not harm them, like risks of trapped in the shelter or the material which have potential to change water quality. Avoid using car tyre as shelters since it may harm the water quality and rather difficult to maintain (because after finishing a growing season, shelters should be cleaned and moved). In a grow out ponds which have a high turbidity, it is good to use some floating material which is tied to the shelter to recognise shelter locations. Some alteratives of shelter for crayfish are shown in figure 11. Figure 11. Two alternatives for marron shelter : PVC (A) and Artificial weed (B) from plastic material. In juvenille stage, nets also can be used as their shelter. 4.4. Potection from predator Protection from predator should be provided and installed properly. Similar with predators in their natural habitat, marron in grow-out ponds also threatened mainly by birds (cormorants, heron, duck etc) and water rats. Since eliminating these predator is against law, ponds should be surrounded by nets and fences to prevent them entering farm area. Nets with 5 - 10 cm mesh size and protected with UV coating will effectively protect the farm in a long time. Figure 12. A marron farm surrounded by nets to prevent birds and other predators to prey on marron. 5. Harvesting Depend on culture conditions, marron can grow to between 60 – 100 g within 12 months and between 100 – 300 g within 24 months. Harvesting can be done if marron reach sizes for human consumption, usually 100 – 350 g or 3 – 10 marron in one kilogram. In extensive system, marron is usually harvested around summer by using traps. Meanwhile, in semi intensive system, harvesting periods can be arranged depend on the management of farming. Continues harvesting every month is possible if farmers allocates many ponds with different period of stocking. Harvesting marron can be done either by draining the ponds or just dragging a seine net to catch the marron without draining the ponds. However, draining the ponds usually more practical because it can be combined with ponds washing as the ponds has been used for grow-out operation for a long time. It is important to harvest marron in cool temperature because it can reduce mortality while harvesting. In order to do that, harvesting should be done in the morning or evening. Large diameter of outlet will make the time of harvesting faster as it drain more water. Shorter time on draining will reduce exposure time of ponds and marron to sunlight. Before opening the outlet to drain the ponds, nets with mesh size smaller than marron’s body should be placed around the outlet to prevent marron flushed with the water. Feed should not given prior to harvesting as it can increase their stress during harvesting. All marron will be easily collected in basin area, where the depth is slightly different with the floor of the ponds. They should be collected as soon as possible in a large tanks and moved to sorting tanks where . After being harvested, several actions need to be done to prepare a good quality of marron for markets. These action consist of gill washing, sorting, purging and transporting live marron to consumer. Gentle care should be taken in these activities to minimize marron being stressed and injured that will lead to mortality. Gill washing should be done after marron harvested from drained ponds. This action is important because marron tends to store water in their gills to enable them breathing outside the water. In harvesting condition, it is very possible that the water in the gills is mixed with muds which contain bacteria. At last, these bacteria, usually Virbrio mimicus, can cause infection to marron and could harm human that consume the crayfish. Gill washing can be done by holding marron in a compartment box and sink it under a clean water for 2-3 minutes. This duration will enable them to clean their gill chamber from mud or other debris. After finishing gill wash, marron should be sort out base on their size and their condition. Undersize marrons can be stocked again in other ponds until they reach consumption sizes. As mentioned before, size of marron will determine their prize in the market. Sorting marron base on their size also reduce mortality to marron that has a smaller size. For example, weight of a single marron with 150 – 200 g are categorised as small marron that is valued for $ 35 /kg, whereas 300 – 350 g are categorized as bigger and are prized more than $ 37/kg at this moment. Another selection parameter that should be applied in sorting marron is their condition. Marron with damaged body and limbs missing often become unacceptable to some costumers. The presence of small parasites (Temnocephala and Epistylis) also has the same impact to costumers. However, salt bathing in 20 -30 g/l for 10 -15 minutes can overcome this problem. During the treatment in a tank, aeration should always be provided to improve their survival rate. Purging of marron is done to remove any food from their gut that can affect their taste and ability to survive in live transportation. During this treatment, no feed given and marron are stocked in a flow through tanks or recirculating aquatic system tanks for about two days. This is a minimal duration to perform purging effectively prior to live transports that require less waste during the transport. Flow through system has advantage on carrying all the waste away. However, a good filtration system on recirculating aquatic system tanks will do the same result. Transporting live marron can be done by putting them in an insulated box with moisture condition and constant cool temperatures. The basic principle of this activity is to keep their gills wet and this condition will allow them to survive more than two days. Bibliography ANONYMOUS. National Symposium on Freshwater Crayfish Aquaculture. In: EVANS, L. H. & O'SULLIVAN, D., eds., 1990. Curtin University of Technology. FALLU, R. & MOSIG, J. 1994. Australian Fish Farmer, Victoria, Agmedia. INGRAM, et al. 1997. Aquatic Life in Freshwater Ponds : A Guide to Identification and Ecology of Life in Aquaculture Ponds and Farm Dams in South Eastern Of Australia, Co-operative Research Centre for Freshwater Ecology. JONES, D. & MORGAN, G. 2002. A Field Guide to Crusctaceans of Australian Waters, Australia, Reed New Holand. MAGUIRE, G. 2004. Marron Farming Workshop, Field day and Trade Show. Perth: Fisheries Departement of Western Australia. MITCHELL, B. D. & COLLINS, R. 1989. Development of Field - Scale Intensive Culture Techniques for The Commercial Production of Yabbie (Cherax destruxtor/albidus). Australia: Centre For Aquatic Science, Warrnammbool Institute of Advance Education. MORISSY, N. M. 1992. An Introduction to Marron and Other Freshwater Crayfish Farming in Western Australia, Fisheries Departement of Western Australia. MOSIG, J. 1998. The Australian Yabby Farmer, Australia, Landlinks Press. MOSIG, J. & FALLU, R. 2004. Australian Fish Farmer, Second Edition, Australia, Landlinks Press. WICKINS, J. F. & LEE, D. O. C. 2002. Crustacean Farming : Ranching and Aquaculture, Blackwell Science. Appendixes Steps of establishing marron farm

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