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Description ..... The Yabby is a freshwater crayfish, also known as a crawchie, crawdad, craybob or even lobbie, it’s dependant on where you come from. ............. Yabbies can live in virtually any body of fresh water including rivers, lakes and dams. Yabbies burrow and are able to survive long periods of drought. ............. Yabbies are omnivores and are very territorial, even cannibalistic. Structure is the key for a good environment, usage of tarps, shade cloth, shrubs and PVC pipes will work well and will sink. ............. Important Yabby Care: DAMSTOCKING YABBIES ............. Yabbies do not need as much acclimatisation as fingerlings. When you receive your yabbies open the foam box next to your pond, before releasing them splash a few buckets of the dam water into the box so their moisture levels are high, this will ensure that they swim immediately into the water and out of site from predators.

GO TO https://www.abc.net.au/news/rural/2017-09-14/redclaw-crayfish-demand-boom-dry-weather-impact/8895726

How to farm red claw crayfish This guide from the FAO Cultured Aquatic Species Information Programme provides information on farming red claw crayfish... GO2 ... https://thefishsite.com/articles/cultured-aquatic-species-red-claw-crayfish

Identity Cherax quadricarinatus von Martens, 1868 [Parastacidae]. FAO Names: En - Red Claw Crayfish, Fr - , Es - ......................... Biological features Relatively large freshwater crayfish, smooth lustrous deep blue to green shell, with males exhibiting bright red colouring on the margins of their large claws. ......................... Males can reach a maximum weight of 500g and females 400g. Juveniles (less than 20 to 30g) can be sexually distinguished by the gonopore position, adjacent to the fifth pereiopods (walking legs) for males and third legs for females. Distinguished from other crayfish by size, colour and the presence of four distinct anterior ridges (carinae) of the carapace. ......................... Four photos showing the culture process for crayfish Two photos showing female crayfish carrying eggs ......................... Profile Historical background The red claw crayfish (Cherax quadricarinatus), referred to throughout the rest of this fact sheet simply by its Australian synonym "redclaw", is a tropical species native to the rivers of north-west Queensland and the Northern Territory in Australia. Although well known to the local inhabitants of this isolated region, it remained effectively unknown to the rest of the world until the late 1980s, when it was trialled for aquaculture. Redclaw proved to be well suited to cultivation, and the redclaw aquaculture industry was born, developing quickly and spreading throughout northern Australia, and soon afterwards overseas. ......................... Redclaw benefits from a host of physical, biological and commercial attributes that make it an excellent candidate for aquaculture. It is physically robust with broad geographic potential, has a simple life-cycle and straightforward production technology, requires low protein diet and is economic to produce. Its texture and flavour compares very favourably with commonly eaten marine crustaceans and, having the appearance of a lobster, is positioned at the premium end of the crustacean market spectrum. Redclaw benefits from a host of physical, biological and commercial attributes that make it an excellent candidate for aquaculture. ......................... Although indigenous to Australia, redclaw has been exported to many other countries where commercial production has now been established. Production technologies, while still evolving, are at a stage where "best management practice" methods have been identified. These technologies are relatively straightforward and the skill levels required of practitioners are not onerous. ......................... Redclaw aquaculture has been established now for more than 25 years, and yet total production is still quite small. This is despite many projections that it would become a significant aquaculture species worldwide, and possibly a rival of the giant freshwater prawn (Macrobrachium rosenbergii). ......................... Aquaculture is an increasingly important source of safe, nutritious, and sustainable seafood for people worldwide. Globally, aquaculture production must double by 2030 to keep pace with demand. These increases in demand for aquaculture products, food security considerations, and job creation have generated an increased need for skilled workers. ......................... Discover how you can be part of this rapidly expanding industry. ......................... Main producers Besides the countries shown in the map, based on FAO statistical returns, redclaw farming activities are also known to exist in Belize, China, Indonesia, Israel, Morocco, Panama, Spain and the USA. Unconfirmed reports of interest in several other countries also exist. ......................... Map of the world with crayfish producing countries highlighted in orange Main producer countries of Cherax quadricarinatus © FAO Fishery Statistics, 2008 ......................... Habitat and biology Redclaw is native to the upper reaches of rivers in northeastern Australia, and in Papua New Guinea. Its preferred habitat is in high turbidity, slow moving streams or static water holes (billabongs) that characterise the rivers in that region. These are flushed seasonally with monsoonal wet season rains, which may wash the redclaw downstream. ......................... Redclaw display a strong tendency to move upstream to the preferred habitat, and to avoid being stranded in the lower river reaches that often dry up in the dry season. Its adaptation to the natural habitat has generated a host of biological attributes that are well suited to aquaculture, as summarised below: ......................... Breeds easily, with no larval stage development Potential for selective breeding; many wild population strains Tolerates high stocking densities Requires low protein diet, not reliant on fishmeal Market position as a high value crustacean Flesh texture and flavour compares favourably with other crustaceans Meat recovery rate acceptable Reaches commercial size in nine months grow-out Survives well out of water for transport to market Straightforward production technology Tolerant of variations in water quality - low dissolved oxygen, wide daily pH changes, low alkalinity, temperature variations, high nutrient loads Tolerates saline water up to 5 percent indefinitely and up to 15 percent for several days. This provides broad geographic potential and a means of enhancing flavour, purging and cleaning before sending to market No destructive burrowing Non aggressive – cannibalism not regarded as an issue Redclaw is a tropical species endemic to northeastern Australia. The harsh physical extremes of this distribution have given this species a robust nature with broad climatic tolerances. ......................... Its preferred temperature range is 23ºC to 31ºC and it will perish at 36ºC. Reproduction will only occur while water temperature remains above 23ºC. ......................... Female redclaw brood their eggs for six-ten weeks, depending on temperature. Most produce between 300 and 800 eggs per brood. There may be between three to five broods during the breeding season. Hatchlings resemble the adult form and remain attached to the underside of the female for several weeks before progressively becoming independent. ......................... Production Production Cycle Black and white sketch showing the production cycle of crayfish Production cycle of Cherax quadricarinatus Production systems Seed supply Selected berried females or mature broodstock from the harvests of grow-out ponds are stocked into juvenile rearing ponds. Breeding and production of seed occurs naturally during the summer months, when temperatures are >25ºC. ......................... Hatchery production There is no hatchery production. Redclaws are reared directly in the juvenile ponds. ......................... Juvenile production Juvenile production and grow-out to market size are managed separately, although both are performed in earthen ponds. A managed juvenile production programme is essential to provide the advanced juveniles required for grow-out, and to make effective use of the superior broodstock selected. Depending on temperature and whether berried females or mature broodstock are used, a culture period of three to four months is necessary to achieve a mean size of juveniles of 5 to 15g. ......................... The two most critical factors in juvenile production are the provision of shelter and food. The general management of juvenile rearing ponds is the same as that described in this fact sheet under on-growing techniques. ......................... Typically juvenile ponds are stocked with mature females and males at a ratio of 4:1 and a density of 1,500/ha, carefully selected as the best of the stock available from grow-out harvest. ......................... Under well managed conditions, 50-100 advanced juveniles will be produced per broodstock female, providing a yield of 60,000 to 120,000 juveniles/ha. At water temperatures above 25ºC, a juvenile production pond stocked with male and female broodstock is ready for harvest in four months. Alternatively, when berried females are stocked, the juvenile production pond is ready to harvest in three months. ......................... To maximise survival and growth of the juvenile redclaw, an abundance of shelter in the ponds is essential. This is usually provided in the form of bundles of synthetic mesh, tied onto a line with a weight at one end and a float at the other. Arranged in this manner, these bundles extend from the pond floor up into the water column providing many spaces and surfaces for the juveniles to utilise. These mesh bundles are stocked at one every 5m2. ......................... Juvenile production ponds are carefully managed to provide an abundance of planktonic organisms which the juvenile crayfish utilise as food. The planktonic organisms include both phytoplankton and zooplankton; it is primarily the latter that are consumed by the juvenile crayfish. As they grow, they progressively consume less plankton and more of the detrital food that occurs on the surface of the shelter material and, more especially, on the mud surface. ......................... Maintaining high levels of plankton involves regular checking of water quality and periodic fertilisation of the water with nitrogen and phosphorus (typically diammonium phosphate at 50 kg/ha). ......................... Harvesting of the juveniles is achieved by a number of methods. Sometimes individual mesh shelters are removed and the juveniles shaken out. However, the most effective method is to employ a flow trap. With this method, the pond is completely drained and all the crayfish are attracted into a trap. From there they can be removed to tanks and sorted, counted and then stocked into the grow-out ponds. ......................... On-growing techniques Although all commercial redclaw grow-out occurs in earthen ponds, there is some interest in tank culture. ......................... Ponds Redclaw aquaculture, both in juvenile and grow-out ponds, is performed in earthen ponds, typically 0.05 to 0.5ha, with a depth of 1.0-2.5m and a V-shape that allows rapid and complete drainage. Water is sourced from surface supplies or underground and should have a pH of 6.5-8.0, hardness of >40ppm, and low levels of salinity (artificial shelters are essential; they should be abundant, and their shape, specification and positioning should permit water to drain out freely and completely as the pond is drained. Stacks of pipes have been found to provide the most effective shelter for redclaw in the grow-out phase. ......................... Aeration is also essential and most frequently provided through airlift pumps, although other forms of aeration such as paddle-wheels and aspirators may be used. The aeration system should provide both oxygen input to the water and water circulation from bottom to top and around the pond. ......................... Grow-out ponds should be prepared with applications of lime, inorganic fertilisers and some organic material such as hay or manure. ......................... Fencing and netting over ponds is essential in areas where predatory birds and other species are prevalent. Grow-out ponds should be prepared with applications of lime, inorganic fertilisers and some organic material such as hay or manure. This initiates a plankton bloom, which provides additional, highly nutritious food and minimises light penetration. ......................... Grow-out necessitates an active stock management approach. Because redclaw breed so readily and profusely, the pond populations must be managed intensively. This includes stocking with known numbers of advanced juveniles of at least 5g. Uniformity of size is very important. Maximum size at stocking should be 10g. Stocking densities of 5-15/m2 are recommended. ......................... The food used will have an important bearing on production. Commercial crayfish pellets are available and have proven to be effective. A feeding frequency of once per day is adequate, preferably at dusk when crayfish are active. ......................... Active management of the pond environment is essential to maximise yields. There should be weekly monitoring of pH, dissolved oxygen and transparency (secchi disk) and monthly monitoring of hardness, alkalinity and ammonia. ......................... All measurements must be made at the water/soil interface on the bottom, and a contingency plan must be developed to counter poor water quality by applications of lime or fertiliser, or flushing of the pond with fresh water. ......................... Drying both juvenile and grow-out ponds between crops is essential to sterilise and re-vitalise the bottom. There is often a considerable build-up of organic waste after a culture period. The most effective management is to dry the pond for one to two weeks until cracks appear. Toxic compounds are broken down and useful nutrients are released. ......................... Crayfish may be manually sexed and stocked into separate ponds, particularly those that are to be grown out to >50g. Avoiding, or at least minimising reproduction in grow-out ponds is important in effective management. Protection against birds, rats and eels, and any other potential predators must be provided. Complete enclosure netting and fencing is essential. Recent economic analysis indicated that the cost of netting (including materials and installation) is equivalent to 15 percent of the value of one crop. As losses to predators may be well in excess of this, netting is very cost-effective. ......................... The maximum grow-out period without grading should be six to nine months to minimise the possibility of un-managed reproduction. At each harvest, the stock must be size-graded and re-distributed as breeding stock, for marketing, for further grow-out or to be culled and discarded. ......................... The runts of each crop are unlikely to achieve market size in a reasonable time and it is best to remove them (and therefore their inferior genetics) from the farm population. ......................... The key factors for redclaw grow-out are ......................... maximise growth and survival avoid reproduction If these principles are applied, an average yield of more than 5 tonnes/ha/crop should be achieved. Tanks Despite the focus of redclaw grow-out being earthen pond systems, there has been regular interest in the use of tank systems. These require only a modest investment in comparison with pond construction, and have therefore attracted great attention. ......................... Unfortunately, tank systems are not likely to provide profitable returns. Redclaw obtains the bulk of its food from decaying matter and associated microbes contained in the pond bottom mud. Although manufactured feeds have been developed for redclaw they do not appear to sustain acceptable growth rates in tank systems. ......................... Similarly, juvenile redclaw, which have slightly different feeding habits to the adults, cannot be cultured successfully in tanks because appropriate food cannot be provided. As a result, the juvenile redclaw become cannibalistic, leaving very few survivors. ......................... The only commercially viable operations for redclaw are earthen pond based. ......................... The level of production likely from redclaw culture in tanks would return considerably less than the operating costs, and certainly far less than the setup costs. Efforts to develop successful commercial tank systems for the cultivation of freshwater crayfish have a considerable history. Both in Australia and overseas, years of work have been applied to this approach, and yet the only commercially viable operations for redclaw are earthen pond based. There exists no confirmed or documented case of commercial success for crayfish production in a tank system. ......................... Feed supply Commercial crayfish pellets are available in some countries, although in many cases pellets formulated for other species are used. The most effective have a protein content of ~25 percent and a lipid content of 8 percent, and are composed primarily of grains. Use of a feeding schedule is critical. Suitable alternatives to crayfish pellets include freshwater prawn (Macrobrachium) or fish pellets. ......................... Harvesting techniques Harvesting may involve a number of methods, although the most effective is the use of a flow-trap; this exploits the strong response of redclaws to flowing water. ......................... A slow but steady flow of water into the pond via a box and ramp illicit movement of crayfish against the flow and into the box. Flow-trapping should involve 95 percent drainage of the pond over 24 hours from dawn to dawn. ......................... There should be several thousand litres of water remaining in the deepest part of the pond at dawn, when the redclaw are removed. This slow drainage enables the crayfish to move out of shelters and with the main body of water, so that they concentrate and respond most effectively to the flow trap. Both the flow trap and the last remaining water must be well aerated or the entire harvest may easily be lost. ......................... The stock should be quickly removed and transported to clean water in a tank system. Care should be taken to minimise crushing by not exceeding 15kg of stock per transport container (typically a 60 x 40 x 40cm fish basket). Other harvesting methods include bait trapping and drain harvesting with manual collection of stock. ......................... Handling and processing The majority of redclaw are sold live; thus after harvesting stock they are held in tanks with flow-through water supply or a recirculation system involving biological filtration. A period of at least 24 hours in the tank to permit purging of the gut is recommended prior to packing for transport. ......................... Redclaw can survive extended periods out of water provided they are kept cool and moist. Packing therefore involves insulated containers containing some moist packing material (foam rubber or wood shavings) and cooling packs. ......................... Production costs A redclaw aquaculture economic model has been developed with data gathered from commercial farms. This model involves a farm size of forty 1,000m2 grow-out ponds and seven 1,000m2 juvenile production ponds, representing a total pond area of 4.7 hectares. The financial evaluation uses a discounted cash flow technique over a 20 year period. The model farm was assumed to annually harvest 394kg of redclaw per grow-out pond from year two onwards. ......................... Redclaw were estimated to take nine months to reach the acceptable market size of 65g mean weight. At this weight the farm-gate price was estimated to be US$12.50/kg. ......................... Initial establishment of the model farm was estimated to cost US$325,000. Included in this cost were land, hired labour, machinery and all farm infrastructure costs. Specifications for the farm layout and pond characteristics were based on "best management practice" recommendations. ......................... In this model farm, redclaw aquaculture was profitable, providing a profit of US$4.91/kg/year. The total costs of production were estimated to be US$7.71/kg/year. Included in these costs were all operating costs, capital costs and allowance for the owner’s labour and management. The discounted payback period, which represents the time to recover the initial outlay, was four years. Sensitivity analyses for prices and yield showed that, at the annual yield of 394kg per grow-out pond, the minimum price for the investment to be profitable was US$7.71/kg. ......................... Similarly, at an assumed price of US$12.50/kg, the minimum annual yield required to be profitable was 2,320 kg/ha. Grow-out periods may vary between 6 months and 15 months depending on the redclaw market weight the grower intends selling. Redclaw market weights and prices were assumed to increase with longer turnoff periods. Based on a sensitivity analysis which compared various grow-out periods, the most profitable option was 9 months and the least profitable was 12 months. ......................... The results from this analysis were very sensitive to prices, survival rates and market weights. Survival rates and market weights are strongly correlated to farm management expertise. Results from established farms applying best practice techniques confirm that the economics of the model are a true and accurate representation of commercial redclaw aquaculture. ......................... Diseases and control measures Several potentially disease causing organisms, including protozoans, bacteria and viruses, have been identified in redclaw. All have been implicated at one time or another in some mortality or poor production from specific farms, although there has never been any documented widespread outbreak of disease. ......................... Farmers are well aware that careful quarantining and good health monitoring and management will minimise the risk of disease. By maintaining good culture conditions that maximise survival and growth, crayfish stress is managed and the threat of disease minimised.