Разведение речных раков: разведение и содержание в домашних условиях. Вред и польза речных раков :: SYL.ru

Раздел II. СОДЕРЖАНИЕ И РАЗВЕДЕНИЕ РАКОВ ПРИРОДНЫЕ ОСОБЕННОСТИ РЕЧНОГО РАКА

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Раздел II. СОДЕРЖАНИЕ И РАЗВЕДЕНИЕ РАКОВ

 

 

ПРИРОДНЫЕ ОСОБЕННОСТИ РЕЧНОГО РАКА

Речные раки – беспозвоночные животные, постоянно пользующиеся большим спросом на всей территории России.

С каждым годом природные популяции уменьшаются, чему способствуют различные эпидемии и особенно браконьерство. Установлено, что природные запасы раков достигают максимума каждые 8 лет, после этого снижаются до минимума.

В последние 15 лет большое внимание уделяется разведению раков в искусственных водоемах. По показателям потребления на душу населения лидируют Греция и Италия. В эти страны раки в свое время были завезены с территории бывшего Советского Союза (в основном из Молдавии, Украины, России).

На внешний рынок эти страны поставляют ежегодно до 11 тысяч тонн товарных раков. Китай, Испания, Португалия тоже поставляют их.

В приусадебных и дачных прудах можно с успехом разводить раков быстрорастущих видов, как широкопалый (Astacus astacus) и длиннопалый (Pontostacus leptodactylus).

На территории Краснодарского края раки обитают в любых пресных водоемах – реках, озерах, лиманах, поймах, водохранилищах, прудах. На территории Краснодарского водохранилища по берегам рек можно без проблем наловить раков, что с удовольствием делают местные жители.

Раки пресноводные очень любят чистоту, не зря их считают индикаторами чистой воды. Глубина водоема обычно колеблется от 1,5 м до 6 м, но может доходить до 7-18 м. Идеальная среда для обитания раков – это береговая линия водоема с затоками, где хорошо произрастает водная растительность. В Краснодарском крае, Ростовской, Астраханской и Вологодской областях это камыши. На территории Краснодарского края в дикой природе раков много находится в реках Челбас, Ея, Кубань, Лаба.

При поедании раками водорослей в организме ускоряется кальциевый обмен, а это способствует затвердению панциря после линьки.

Раки явно предпочитают достаточно плотное дно (песок или глина) с присутствием известковых пород, камней, а также водоемы с нормальной или повышенной минерализацией воды. Если это небольшая запрудина возле реки в вашем огороде, то грунт возле берега должен быть таким, чтобы ракам было удобно строить норы (раки также могут находиться и под камнями, корнями, пнями). Чаще всего раки строят норы на отвесных тенистых берегах, где мало солнца. К примеру, в Краснодарском крае это обязательно камыши, где по берегам растут ива, верба, акация. Размеры нор колеблются (в среднем): длина – от 10 до 40 см, ширина – 5-20 см, высота – от 3 до 18 см. Зимой норы раков расположены на самом дне, а летом – ближе к раю берега, в зависимости от температуры.

Раки роют свои норы с помощью ног и хвоста, опираясь на передние клешни. Хвосты ракам нужны не только для рытья нор, но и для плавания. Плавают они задом наперед и при этом бьют хвостами по воде. Очень редко бывает, что раки, покидая водоемы с загрязненной водой, передвигаются по суше.

В воде с кислой реакцией они, как правило, не живут. Оптимальное количество растворенного в воде кислорода для речных раков – 7–8 мг/л, однако допустимо кратковременное снижение его уровня до 2–4 мг/л.

Раки, как правило, ведут ночной образ жизни, но если почуют добычу, то будут стремиться к ней и днем. Самки раков всегда сидят в норах поодиночке, а самцы во время зимовки нередко собираются группами.

Раки – раздельнополые животные. Самцы длиннопалых раков достигают половозрелости на третий год при длине тела не менее 7–9 см, а самки – только на четвертый год при длине тела 6–7 см. Как правило, раки-самцы в 2–3 раза крупнее самок. Спаривание происходит либо осенью (октябрь – ноябрь), либо в конце зимы – начале весны (февраль – март). Россия – страна большая, так что все зависит от региона.

Продолжительность спаривания – 15–20 дней, оплодотворение внешнее. Самец преследует самку и, охватив ее ногами, прижимается к нижней стороне самки своей нижней стороной и через половые отверстия переливает сперму во внутренние половые органы самки.

Оплодотворение икры у речных раков происходит внутри тела.

При спаривании самка сильно сопротивляется, старается вырваться. Если самец оказывается слабее, она уходит от него. Самка скрывается в норе и выходит из нее только днем, когда самцы отдыхают в убежищах. Самец может оплодотворить до 4 самок подряд.

Через 20–25 дней после спаривания самки приступают к икрометанию, выпуская икру через половые отверстия, которая тут же приклеивается под плесом к ложноножкам и остается там до вылупления личинок. Это самый тяжелый период в жизни самки рака.

Икра требует непрерывного промывания водой, обогащенной кислородом, поэтому самка гонит воду плесом, подгибая и разгибая конец хвоста. В спокойной воде, особенно когда самка сидит в норе, вода застаивается, обедняется кислородом и обогащается продуктами обмена веществ, из-за этого икра погибает.

Икра рака легко повреждается мелкими беспозвоночными – водяными скорпионами, жуками-гладышами и плавунцами. Самка рака постоянно промывает икру от грязи, водорослей и плесени.

У самки рака может быть от 120 до 500 икринок.

Потомство рака вылупляется, в зависимости от территории России и погоды, в начале или во второй половине лета. К примеру, сочинские и ярославские раки находятся в разных климатических поясах. Внешне личинки мало отличаются от взрослых раков, за исключением размеров. Длина однодневных личинок достигает от 9-16 мм. Первое время они остаются прикрепленными под плесом у самки. Через 10–12 дней начинают плавать возле самки, при любой опасности быстро прячутся под плес. Только после 45 дней личинки навсегда покидают самку. Растут личинки медленно и к осени едва достигают 3–3,5 см длины. К концу второго года жизни молодые раки вырастают до 7 см, прибавляя каждый год по 1 см. В возрасте 8-10 лет раки достигают до 10–11 см в длину.

Вылупление и развитие речного рака происходит следующим образом. Рачок вылупляется из икры, разрывая яйцевую оболочку вдоль нижней части тела зародыша движением брюшка и конечностей. Вылупившаяся личинка повисает на так называемой «малиновой нити», и через двое суток эта нить обрывается, но личинка ухватывается за стебелек или оболочку икринки клешнями, которые сильно заострены и имеют на концах загнутые крючочки. В таком положении личинки пребывают от 1 до 4 дней, питаясь желтком из желточного мешка, который находится под спинным щитком головогруди. Панцирь личинки 1-й стадии мягкий, поэтому тело и масса ее увеличиваются. На этой стадии личинки еще не похожи на взрослого рака.

2-я стадия развития личинки начинается после ее первой линьки, которая наступает на пятый день после вылупления. Желточный мешок к этому времени исчезает, головогрудь удлиняется, панцирь становится тверже, чем у личинки первой стадии, раструм выпрямляется, личинки поедают яйцевую оболочку. На расширившемся тельсоне появляются веерообразно расположенные щетинки. Личинки становятся очень подвижными, нередко в поисках пищи уходят далеко от самки, но в случае опасности прячутся под ее брюшком (плесом).

После второй линьки личинки переходят в 3-ю стадию, и метаморфоз завершается. Личинка приобретает внешний вид взрослого рака, ведет самостоятельный образ жизни и окончательно покидает самку.

Личинки 3 стадии растут до полного затвердевания панциря (размер – 1,2 см, масса – 34,6 мг). На сроки и количество линек очень влияет температура воды. В Ростовской области молодь растет в основном 2,5–3,5 месяца. За этот период происходит 6–9 линек, так как в прудах температура воды обычно выше, чем в естественных водоемах. К концу сезона личинки 3-й стадии переходят в стадию сеголеток, достигают 5–6 см в длину и массы около 6 г (иногда 7, 8 и 14 г) в искусственных водоемах и соответственно 3 см и 8-10 г в реках.

Двухлетние раки за теплый сезон линяют в прудах 8–9 раз и достигают промысловой длины 10 см, массы 32 г, а некоторые даже максимального размера 12,3 см и 70,5 г веса.

Молодь, выращенная в реках и озерах, достигает промысловых размеров на третье или четвертое лето.

Выживаемость сеголеток в прудах при хорошей кормовой базе за вегетативный период значительно больше (85–90), чем в естественных водоемах (10–15 %). Высокий темп роста и выживаемость молоди речных раков объясняется хорошими кормовыми и температурными условиями, которые они находят в искусственных водоемах, в то время как в реках молодь не получает даже минимального рациона, покрывающего расходы энергии на поиски пищи и обмен веществ в организме.

Половозрелость речных раков в естественных условиях наступает на третьем году жизни при минимальном размере самок 6, 7 см. Сроки спаривания зависят от условий в водоеме и температуры воды, что обычно наблюдается, например, в Ростовской области – в марте – апреле при температуре воды 8-12 °C; личинки из икры вылупляются при температуре воды 21–24 °C во второй половине мая – первой половине июня. К самостоятельному обитанию личинки в этом регионе переходят через 10–14 дней после вылупления.

90000 Breeding Crayfish 90001 90002 90003 Breeding Crayfish 90004 90005 90006 90002 In the text below I will try to give a short overview over some of the basics when breeding crayfish. Particular species may have other behaviours and demands. It should also be said that my main experience as an aquarist is related to fish, but I will try conveying what little knowledge I’ve got. 90006 90002 90003 Sexing Crayfish: 90005 90004 Sexing crayfish is not always that easy.The genital openings are located on different places on the body depending on whether it’s a male or a female. Males have there genital openings behind / under there posterior pair of legs. Females have their genital openings under the third pair of legs counted from the posterior. However, many individuals have one male as well as one female genital opening, making the sexing much more complicated. But they are always either male or female, usually male but you can not be sure. 90006 90002 90003 Mating and egg carrying: 90005 90004 In aquarium spawning is possible anytime of the year.The male makes a little sperm packet and places it on the female’s stomach. The female then spawn her eggs passing them trough the sperm packet so that the eggs get fertilized. It is not uncommon for the female to loose a claw during this process. She then places the eggs under her tail where they will be kept until they are ready to be released. How long a period this will be depends on the water temperature and the species, but it will be at least 4 weeks. A lot of other factors can also affect the length of the egg carrying period such as water quality and food supply and quality.The mother will watch over the young a short period after birth. 90006 90002 90003 Fry: 90005 90004 The fry is very small when they are born but fully developed crayfish. Fry are usually detritus feeders which mean that they will feed on decomposing plant parts and food leftovers they can find while scouring the bottom. Vegetable food is preferred and they can be feed boiled lettuce leaves that are left to decay in the aquarium. Beware of the water quality. Fry is often very cannibalistic and a large aquarium is required if you want I higher number fry to survive.Sorting fry after size may help higher to survival rate. 90006 90024 90025 90026 90027 90004 90003 Crayfish 90005 — picture by ncbuckeye 90031 90032 90033 90034 90003 Breeding: 90005 90004 Now you know about their breeding behaviour and how to raise the fry, but how can you get them to breed in the first place? Well, first of all you have to give them the right environment and good food to get them in a condition in which they can spawn.Some species also needs different triggers to breed. These triggers may be a change in the amount of light and number of light hours, a change in temperature, change of circulation etc. 90002 90003 Feeding: 90005 90004 Crayfishes usually accepts most kind of foods and I would recommended feeding them a diet based on boiled lettuce, sinking pellets, shrimps and once or week or so fish meat. This will get them in good condition and help the female survive the spawning period since she usually do not eat while she is carrying eggs.90006 90002 90003 Housing / environment: 90005 90004 Many crayfish species can be kept in relatively small aquariums, but I recommend using larger aquariums since this lower the pressure on the females from the males. The aquarium should be decorated so that a lot of hiding places of suitable size is created. Hiding places can be created using rocks, roots, flowerpots, coconuts, PVC pipes and so on. It’s important that there is at least one, preferably several, hiding places for each crayfish.90006 90002 90003 Did not find the info you were looking for? Register for free and ask your question in our Aquarium forum! 90005 90004 Our knowledgeable staff usually responds to any question within 24 hours 90004 90006 90054 Related Articles 90055 90002 Amano shrimp- Information about Amano shrimp 90004 Amano Algae Eating Shrimp — An article about the algae eating Amano shrimp 90004 Apple snail — An introduction to apple snails. 90004 Aquarium crabs — A guide to aquarium crabs 90004 Black Mystery Snail — An introduction to the Black Mystery Snail 90004 Breeding of Red Clawed Mangrove Crabs — How to breed red clawed crabs 90004 Freshwater shrimp — Information about Freshwater shrimp 90004 Ghost shrimp — Information about Ghost shrimp 90004 Malaysian Rainbow Shrimp — Information on how to keep and breed this shrimp species.90004 Red Cherry Shrimp — A guide to this Algae eating shrimp. 90004 Red clawed lobsters — A short overview of red claw lobsters (crayfish) 90004 Red Nosed Shrimp — information on keeping this shrimp in aquarium. 90004 Snails: Friend or Foe in the Aquarium? — The biology of snails. Their advantages and disadvantages in an aquarium. How to keep them in check. 90006 .90000 How to farm red claw crayfish 90001 90002 Identity 90003 90004 90005 Cherax quadricarinatus 90006 von Martens, 1868 [Parastacidae] 90007 90008 90004 FAO Names: En — Red Claw Crayfish, Fr -, Es — 90007 90011 90012 90004 Biological features 90007 90008 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 500 g and females 400 g. Juveniles (less than 20 to 30 g) 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. 90011 90004 Image gallery 90007 90019 90020 90002 Profile 90003 90004 Historical background 90007 90008 The red claw crayfish (90005 Cherax quadricarinatus 90006), 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. 90011 90008 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. 90030 90011 90008 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 (90005 Macrobrachium rosenbergii 90006).90011 90004 Main producers 90007 90008 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. 90011 90008 90041 90011 90008 90005 Main producer countries of Cherax quadricarinatus (FAO Fishery Statistics, 2008) 90006 90011 90004 Habitat and biology 90007 90008 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: 90011 90051 90052 Breeds easily, with no larval stage development.90053 90052 Potential for selective breeding; many wild population strains. 90053 90052 Tolerates high stocking densities. 90053 90052 Requires low protein diet, not reliant on fishmeal. 90053 90052 Market position as a high value crustacean. 90053 90052 Flesh texture and flavour compares favourably with other crustaceans. 90053 90052 Meat recovery rate acceptable. 90053 90052 Reaches commercial size in nine months grow-out. 90053 90052 Survives well out of water for transport to market.90053 90052 Straightforward production technology. 90053 90052 Tolerant of variations in water quality — low dissolved oxygen, wide daily pH changes, low alkalinity, temperature variations, high nutrient loads. 90053 90052 Tolerates saline water up to 5 ‰ indefinitely and up to 15 ‰ for several days. This provides broad geographic potential and a means of enhancing flavour, purging and cleaning before sending to market. 90053 90052 No destructive burrowing. 90053 90052 Non aggressive — cannibalism not regarded as an issue.90053 90080 90008 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 23 ºC to 31 ºC and it will perish at 36 ºC. Reproduction will only occur while water temperature remains above 23 ºC. 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. 90011 90002 Production 90003 90004 Production Cycle 90007 90008 90041 90011 90008 90005 Production cycle of Cherax quadricarinatus 90006 90011 90002 Production systems 90003 90004 Seed supply 90007 90008 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> 25 ºC. 90011 90004 Hatchery production 90007 90008 There is no hatchery production. Redclaws are reared directly in the juvenile ponds. 90011 90008 90105 Juvenile production 90106 90011 90008 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 3 to 4 months is necessary to achieve a mean size of juveniles of 5 to 15 g. 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 ongrowing 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 25 ºC, 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 5 m 90109 2 90110. 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. 90011 90004 Ongrowing techniques 90007 90008 Although all commercial redclaw grow-out occurs in earthen ponds, there is some interest in tank culture.90011 90008 90105 Ponds 90106 90011 90008 Redclaw aquaculture, both in juvenile and grow-out ponds, is performed in earthen ponds, typically 0.05 to 0.5 ha, with a depth of 1.0-2.5 m 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> 40 ppm, 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. 90011 90008 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. 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 5 g. Uniformity of size is very important.Maximum size at stocking should be 10 g. Stocking densities of 5-15 / m 90109 2 90110 are recommended. 90011 90008 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. 90011 90008 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> 50 g. 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, and avoid reproduction. If these principles are applied, an average yield of more than 5 tonnes / ha / crop should be achieved. 90105 Tanks 90106 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, can not be cultured successfully in tanks because appropriate food can not be provided. As a result, the juvenile redclaw become cannibalistic, leaving very few survivors.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.90011 90004 Feed supply 90007 90008 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. 90011 90004 Harvesting techniques 90007 90008 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 15 kg of stock per transport container (typically a 60 x 40 x 40 cm fish basket). Other harvesting methods include bait trapping and drain harvesting with manual collection of stock. 90011 90004 Handling and Processing 90007 90008 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. 90011 90004 Production Costs 90007 90008 A redclaw aquaculture economic model has been developed with data gathered from commercial farms.This model involves a farm size of forty 1 000 m 90109 2 90110 grow-out ponds and seven 1 000 m 90109 2 90110 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 394 kg of redclaw per grow-out pond from year two onwards. Redclaw were estimated to take nine months to reach the acceptable market size of 65 g 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 394 kg 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.90011 90004 Diseases and Control Measures 90007 90008 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. 90011 90156 90157 90158 90159 Disease 90160 90159 Agent 90160 90159 Type 90160 90159 Syndorme 90160 90159 Measures 90160 90169 90158 90171 Systemic Rickettsia 90172 90171 Rickettsia-like organism 90172 90171 Bacteria 90172 90171 Lethargy; poor feed response; low growth rate; significant mortality 90172 90171 For heavy farm infections, complete de-stocking & sterilisation of ponds 90172 90169 90158 90171 White tail 90172 90171> td> Microsporidian 90172 90171 Abdominal muscle becomes opaque; low prevalence but high mortality 90172 90171 Uncommon in farm populations; no specific measures 90172 90169 90158 90171 Redclaw baculovirus 90172 90171 Cherax quadricarinatus bacilliform virus CqBV 90172 90171 Virus 90172 90171 Associated with lethargic & moribund crayfish; high prevalence but low pathogenicity 90172 90171 No specific measures 90172 90169 90204 90205 90008 90105 Suppliers of Pathology Expertise 90106 90011 90008 In Australia, the Queensland Government provides a diagnostic service for farm stocks including redclaw crayfish: www.deedi.qld.gov.au 90011 90002 Statistics 90003 90004 Production Statistics 90007 90004 Global Aquaculture Production of Cherax Quadricarinatus (FAO Fishery Statistic) 90007 90008 90219 90011 90008 Annual production of redclaw in Australia has remained at less than 400 tonnes for the past decade through to 2011. The regulatory environment in Australia has stifled investment despite the excellent production credentials of the species.Meanwhile, in other countries, redclaw production has become established, but with only minor industry growth. In Mexico there is possibly around 50 tonnes of production, but less than ten tonnes each from Belize, Panama and the United States of America. Ecuador at one stage during the late 1990s had significant redclaw production, particularly for juveniles to stock new farms but this did not persist, and total production is currently negligible. Redclaw farms of substantial scale have been established in Morocco and in Spain, but production from these locations is unknown.Redclaw have been cultivated in southern China since the mid 1990s, although annual production is said to be less then 100 tonnes (it is not yet specifically recorded in statistical returns to FAO). 90011 90004 Market and Trade 90007 90008 Redclaw are commonly marketed in 20 g size grades ranging from 30-50 g (at approximately US $ 9.50 / kg) to> 120 g (at approximately US $ 18.00 / kg). The smaller grades are commonly used in buffet style presentations, with the larger animals featuring in a-la-carte restaurants, both as entree and main course dishes.In Australia, export opportunities have been identified through considerable market research. However, sales to date have been limited by the small production volume and therefore the risk of inconsistent supply. At present 60 percent of redclaw are sold within Queensland and 10 percent sold interstate; the remaining 30 percent exported, primarily to Hong Kong. Production in other countries tends to be marketed locally. There are three steps in the marketing chain; producer, wholesaler and restaurateur.There are effectively no retail sales of the raw product. While selling direct to restaurants may result in slightly higher prices, the practice can have a limiting effect on market growth. A good wholesaler can increase the market penetration of redclaw by cross-selling while servicing customers from their existing product lists. Farm-gate sales are substantial; however, the volumes are likely to decrease as more coordinated marketing through wholesalers develops. Wholesalers tend to price redclaw lower than marine lobsters but higher than shrimp.Generally they are marketed alongside slipper lobsters, small spiny lobsters or small clawed marine lobsters. A clear marketing attribute for Australian redclaw is its reputation as a product from clean water, free of medical or chemical additives. Product is purged prior to sale and is often held in saltwater (up to 15 ‰), which improves the flavour and its attractiveness to Asian markets. Redclaw are mainly sold as a live product, although some processing, particularly cooking and freezing is undertaken.Fresh redclaw have a lustrous shell, deep blue to green in colour. Cooked, they have the bright red appearance typical of premium crustaceans. 90011 90002 Status and Trends 90003 90008 A comprehensive research and development programme was operated between 1988 and 2000 by the Queensland Government from a research station at Walkamin. This covered aspects of preliminary assessment, development of production technology, demonstration farms and selective breeding.Research programmes have also operated in the USA (Auburn University, Kentucky State University), Mexico (CIBNOR) and Israel, some of which remain current. However, while research continues to provide useful information, particularly in regard to nutrition and reproduction, it is not a lack of knowledge that is limiting industry development. Despite all its positive attributes, the reasons for the lack of redclaw farming expansion remain uncertain. Clearly, market demand for such crustaceans remains strong throughout the world, and freshwater production is generally less exposed to the conflicting resource use issues that face marine aquaculture.Profitability, based on Australian farm modelling, appears to be strong. In Australia the regulatory environment is clearly an obstacle, and the risk of environmental permits not being issued retards investment. Furthermore, the initial apparent success of many small farms that were in fact not of an economically viable scale has resulted in a stagnant industry that is not attractive to new investment. In other countries, redclaw farming has similarly failed to gain momentum. In many cases the species has been translocated to regions where the climate is simply not suited, such as the USA, where cool winters are not conducive to profitable production.This applies equally to many other countries with sub-tropical environments. Redclaw is a tropical species and thus its farming can only be commercially viable in locations with a tropical climate. Redclaw farming appeared well suited to Ecuador where development grew quickly from 1994 through 1998 and then promptly collapsed. The reason was purported to be low market price, and therefore lack of profitability. There have been enough documented cases of high productivity to verify the production capacity of this species.Similarly, market research suggests that acceptable farm-gate prices can be achieved for large volumes that would sustain a viable business. The missing elements appear to be investment in farms of appropriate scale and site selection in tropical locations where the climate will support premium growth. If these criteria are met, redclaw farming may be established and provide a foundation for substantial growth. 90011 90002 Main Issues 90003 90008 Redclaw farming faces several marketing challenges.Typical of most new industries, very little promotion has been undertaken, thus consumer awareness internationally is relatively low. In Australia the industry is composed of a high number of small enterprises making the marketing quite fragmented. Localised marketing groups consisting of several cooperative growers with common purpose have been trialled with limited success. These have established quality standards, brand names and promotional material to more effectively market their collective production in a coordinated manner.The challenge for industry is to increase production through expansion and new investment and to lift production volumes to a point where the substantial quantities required by identified markets can be consistently supplied. Redclaw is considered an invasive species, and thus its introduction into many areas outside its natural distribution is considered risky. Unfortunately, such translocation has been widespread for more than two decades, and the impacts of this are now being revealed. To date such impacts appear to be negligible, there being no documented cases of significant ecological consequences such the displacement or competitive exclusion of native species.While the risk remains, and may be manifested in more subtle ways, strict quarantine and security measures should be applied to redclaw farming. The biological characteristics of redclaw are not typical of a highly invasive species. It has reasonably high sensitivity to low temperature, which precludes its survival in waters where temperature falls below 10 ºC. It has a relatively low fecundity and is highly susceptible to predation. Nevertheless, it is a robust species, and every effort should be made to avoid its release into natural waterways.90011 90004 Responsible Aquaculture Practices 90007 90008 The redclaw farming industries around the world are still too small to garner much attention. The prospect of significant growth in production of this species is supported by excellent production characteristics and production systems that are environmentally sustainable. Freshwater pond based aquaculture, such as used for redclaw, has a distinct advantage over mariculture, in that the water can be used before or after the production phase for other agricultural purposes such the irrigation of crops.Production inputs tend to be quite organic, and indeed it would take only minor modification of established practices to meet organic certification requirements. Although best management practices have been developed and documented for redclaw that seek to maximise production, there is as yet no code of practice that specifically incorporates sustainability issues. As the established methods are already of a highly sustainable nature, redclaw aquaculture may be an attractive proposition for an increasingly enlightened rural production sector.90011 90002 References 90003 90004 Bibliography 90007 90008 Barki, A., Karplus, I., Manor, R., Parnes, S., Aflalo, E.D. & Sagi, A. 2006. Growth of redclaw crayfish (Cherax quadricarinatus) in a three-dimensional compartments system: Does a neighbor matter? Aquaculture, 252: 348-355. Cortes-Jacinto, E., Villarreal-Colmenares, H., Cruz-Suarez, LE, Civera-Cerecedo, R., Nolasco-Soria, H. & Hernandez-Llamas, A. 2005. Effect of different dietary protein and lipid levels on growth and survival of juvenile Australian redclaw crayfish, Cherax quadricarinatus (von Martens).Aquaculture Nutrition, 11: 283-291. Evans, L.H. & Edgerton, B.F. 2002. Chapter 10. Pathogens, Parasites and Commensals. In: D.M. Holdich (ed), Biology of Freshwater Crayfish, pp. 377-438. Blackwell Science, Oxford. Gutierrez-Yurrita, P.J. 2005. The problem of introducing alien crayfish. Crayfish News (Newsletter of the International Association of Astacology), 27 (2): 12-13. Holdich, D.M. 2002. Biology of Freshwater Crayfish. Blackwell Science, Oxford. 702 pp. Jones, C.M. 1990. The Biology and Aquaculture Potential of the Tropical Freshwater Crayfish, Cherax quadricarinatus.Report No. QI90028. Department of Primary Industries, Queensland, Brisbane, Australia. 109 pp. Jones, C.M. 1998. Redclaw Crayfish. In: K.W. Hyde (ed), The New Rural Industries. A Handbook for Farmers and Investors, pp. 127-133. Rural Industries Research and Development Corporation Canberra. Jones, C.M. (Ed.). 2000. Redclaw Crayfish Aquaculture. Recommended Practices for Redclaw Crayfish Aquaculture based on Research and Development Activities, 1998. through 2000. Cairns, Australia. Queensland Government, Department of Primary Industries and Fisheries.61 pp. Jones, C.M. & Grady, J. 2000. Redclaw from harvest to market: a manual of handling procedures. Report No. QI99083. Department of Primary Industries, Queensland, Brisbane. 36 pp. Jones, C.M. & Ruscoe I.M. 2000. Assessment of stocking size and density in the production of redclaw crayfish, Cherax quadricarinatus (von Martens) (Decapoda: Parastacidae), cultured under earthen pond conditions. Aquaculture, 189: 63-71. Jones, C.M., McPhee, C.P. & Ruscoe, I.M. 2000. A review of genetic improvement in growth rate in redclaw crayfish Cherax quadricarinatus (von Martens) (Decapoda: Parastacidae).Aquaculture Research, 31: 61-67. Jones, C.M. & Ruscoe, I.M. 2001. Assessment of five shelter types in the production of redclaw crayfish Cherax quadricarinatus (Decapoda: Parastacidae) under earthen pond conditions. Journal of the World Aquaculture Society, 32: 41-52. Lawrence, C. & Jones, C. 2002. Chapter 17. Cherax. In: D.M. Holdich (ed), Biology of Freshwater Crayfish, pp. 635-670. Blackwell Science, Oxford. McPhee, C.P., Jones, C.M. & Shanks, S.A. 2004. Selection for increased weight at nine months in Redclaw crayfish (Cherax quadricarinatus).Aquaculture, 237: 131-140. O’Sullivan, D. Fielder, D. & Jones, C. 2003. Chapter 20. Freshwater Crustaceans. In: J.S. Lucas & P.C. Southgate (eds), Aquaculture: Farming Aquatic Animals and Plants, pp. 420-442. Blackwell Publishing Oxford. Pavasovic, A., Anderson, A.J., Mather, P.B. & Richardson, N.A. 2007. Influence of dietary protein on digestive enzyme activity, growth and tail muscle composition in redclaw crayfish, Cherax quadricarinatus (von Martens). Aquaculture Research, 38: 644-652.Romero, X. 2002. Ups and downs of red claw crayfish farming in Ecuador. World Aquaculture, 33 (2): 40-46. Romero, X. & Jimenez, R. 2002. Histopathological survey of diseases and pathogens present in redclaw crayfish, Cherax quadricarinatus (Von Martens), cultured in Ecuador. Journal of Fish Diseases, 25: 653-667. Thompson, K.R., Muzinic, L.A., Engler, L.S., Morton, S.R. & Webster, C.D. 2004. Effects of feeding practical diets containing various protein levels on growth, survival, body composition, and processing traits of Australian red claw crayfish (Cherax quadricarinatus) and on pond water quality.Aquaculture Research, 35: 659-668. Thompson, K.R., Muzinic, L.A., Engler, L.S. & Webster, C.D. 2005. Evaluation of practical diets containing different protein levels, with or without fish meal, for juvenile Australian red claw crayfish (Cherax quadricarinatus). Aquaculture, 244: 241-249. 90011.90000 Dwarf Mexican Crayfish — Detailed Guide: Care, Diet, and Breeding 90001 90002 90003 90004 90002 Having an aquarium with Dwarf Mexican crayfish (Cambarellus patzcuarensis) is no easy task. There are plenty of rules to be followed and preparations to be made in order to keep your crayfish happy and healthy. That is why knowing all you can about your little critters will help you keep them thriving. Therefore, as usual, I combined different results of scientific studies and experience of aquarists in this guide to provide all information about Dwarf Mexican crayfish.90004 90002 90008 Dwarf Mexican crayfish is a robust, tolerant and relatively easy to breed. They will not drastically limit your options as their bigger cousins ​​do. In some cases, they can be even one of the best candidates for beginners! However, if you are planning to keep Dwarf Mexican crayfish in a community tank with fish or shrimp the risk of aggression remains. 90009 90004 90002 I would like to start off by saying that the term Dwarf Mexican crayfish refers to several different species called the Cambarellus.Coming from the Cambaridae family they are one of the few types of crayfish that can be kept in captivity relatively safely. Other types of crayfish (90008 Blue crayfish, 90009 90008 Red crayfish, Marbled crayfish, Cherax Destructor, etc 90009) are known to the wildlife community as killers and diggers. They got their nicknames from the way they kill other fish, dig at the bottom of the tank, and completely destroy any plants in the tank. 90008 90009 90004 90019 90008 Quick Notes about Dwarf Mexican Crayfish 90009 90022 90023 90024 90025 90026 90008 Name 90009 90029 90026 90008 Dwarf Mexican Crayfish 90009 90029 90034 90025 90026 90008 Common Names 90009 90029 90026 Mexican Crayfish, Orange Crayfish 90029 90034 90025 90026 90008 Scientific Name 90009 90029 90026 Cambarellus patzcuarensis var orange 90029 90034 90025 90026 90008 Tank 90009 90008 size (optimal) 90009 90029 90026 10 gallons (~ 40 liters) 90029 90034 90025 90026 90008 Keeping 90009 90029 90026 Easy-medium 90029 90034 90025 90026 90008 Breeding 90009 90029 90026 Easy-medium.90029 90034 90025 90026 90008 Size 90009 90029 90026 up to 4 — 5 cm (~ 2 inches) 90029 90034 90025 90026 90008 Optimal Temperature 90009 90029 90026 18 — 24 ° C (~ 65 ° F — 75 ° F) 90029 90034 90025 90026 90008 Optimal PH 90009 90029 90026 7.5 — 8.0 (6.5 — 9.0) 90029 90034 90025 90026 90008 Optimal GH 90009 90029 90026 3 — 18 90029 90034 90025 90026 90008 Optimal KH 90009 90029 90026 3 — 15 90029 90034 90025 90026 90008 Optimal TDS 90009 90029 90026 200 — 300 (100 — 500) 90029 90034 90025 90026 90008 Nitrate 90009 90029 90026 Less than 20 ppm 90029 90034 90025 90026 90008 Diet 90009 90029 90026 Detritivore / omnivore 90029 90034 90025 90026 90008 Temperam 90009 90008 ent 90009 90029 90026 Conditionally Peaceful 90029 90034 90025 90026 90008 Life span 90009 90029 90026 up to 2 years 90029 90034 90025 90026 90008 Color Form 90009 90029 90026 Orange, brown, rust, marbled.90029 90034 90167 90168 90019 90008 Dwarf Mexican Crayfish 90009 90008 and other Dwarf Species of Crayfish 90009 90022 90002 According to the study, despite the fact that 17 currently recognized taxa have been described in, or assigned to, the genus Cambarellinae, little analysis of the genus exists. They all look very similar, they are all small (about 4-5 cm or 2 inches) and can be called dwarf crayfish. 90004 90002 Nowadays, on the market, we can find many varieties of dwarf crayfish, which classification based on the color.For example, 90004 90002 1. Cambarellus ninae — brown-colored, 90180 2. Cambarellus montezumae — yellow-colored, 90180 3. Cambarellus patzcuarensis — orange-colored, 90180 4. Cambarellus shufeldtii — grey / reddish to brown-colored, 90180 5. 90008 Brazos Dwarf Crayfish (Cambarellus texanus) 90009. 90004 90002 However, frankly saying, this method of «classification» is completely unreliable. The point is that these species of dwarf crayfish can crossbreed. As a result, some aquarists believe that Cambarellinae patzcuarensis is not a pure line anymore.It is a hybrid version of C. montezumae and C. patzcuarensis (in order to get better / intense coloration). Basically, it means that nobody can be sure what kind of species they might have! 90008 90009 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008 Description 90009 90022 90002 90198 Dwarf Mexican crawfish comes from Lake Pátzcuaro, a volcanic crater lake in Michoacán which is located in the southwest of the major city of Morelia, Mexico. Wild individuals of this crayfish are mostly tan, brown, and rust color.90004 90002 However, Dwarf Mexican crawfish are also available in bright colored morphs that are dramatically different from their normal, relatively drab, wild type coloration. The orange color morph of the dwarf species originated in the Netherlands (bred by Juan Carlos Merino in the 1990s). 90004 90002 This color morph also called «CPO — Cambarellus patzcuarensis var orange» is a very attractive and popular strain among hobby keepers. Actually, it completely took over the pet niche for this species.Once again, this mutation comes from the crayfish being bred in captivity and not in the wild. 90004 90002 Mexican dwarf orange crayfish is suitable for smaller sized tanks (attaining a maximum length of 4-5 cm or 2 inches). 90004 90002 The lifespan of these tiny bright creatures is only about 2 years but have been known to live even a little bit longer. 90004 90002 90008 Facts 90009: Dwarf Mexican crayfish (Cambarellus patzcuarensis) is listed on the IUCN red list of endangered species.90008 90009 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008 Behavior 90009 90022 90002 In most guides about the Dwarf Mexican crayfish, you will see that they are not aggressive creatures but instead are known for their peaceful nature. Well, compared to many other crayfish, this is true … but only to some degree. 90004 90002 These creatures despite their size are quite territorial in nature and will defend their homes and threaten each other if they come too close to each other.They have claws not for nothing! 90004 90002 Dwarf Mexican crayfish (mostly males) can be especially aggressive towards their own kind. Therefore, if you overpopulate your tank they will «regulate» the number with their own way. In addition, from time to time you will notice that one or two would lose an arm. Of course, it will grow back. However, it shows us their temper. 90004 90002 Another thing that you should remember that these crayfish are excellent escape artists. They have quite strong legs (to get out of the tank) and can spend some time out of the water.90004 90002 90008 Note 90009: That is why, when keeping any type of Dwarf crayfish, it is a good idea to make sure the water line in your aquarium is not too high. 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008 Male and Female Difference 90009 90022 90002 90239 The female and male species can be told apart by looking at the lower part of their abdomen (the lower part of the white section of the underbelly). 90004 90002 Males have an extra set of pleopods used for internal fertilization.Therefore, if you see that there is like a triangular-ish forming of small legs. That will indicate a male. 90004 90002 Females have seminal receptacle and lack the extra pleopods found behind the walking legs on males. Females do not have the same section. There will not be that triangular-ish forming of small legs. What you will see is a small nub. That will indicate a female. 90004 90002 90008 Note 90009: It is easy to differentiate males and females once they hit about 1/2 an inch (~ 1.5 cm). At this size, they will be about 2 months old. 90004 90019 90008 Keeping 90009 90008 Dwarf Mexican Crayfish 90009 90022 90002 90256 If you have a tank with Dwarf Mexican crayfish it is recommended to having no more than two in a 10-gallon tank and no more than 4 in a 20-gallon tank. 90004 90002 Exactly the same as shrimp, Crayfish are extremely sensitive to nitrates and ammonia (90008 you can read more about «Nitrates in Shrimp Tank. How to Lower them» right here 90009). Therefore, if the tank is not cycled do not add the crayfish to cycle the tank.They will not survive. 90004 90002 Make sure you have your pH levels at least 7.5 — 8.0. The point is that Dwarf Mexican crawfish comes from Lake Pátzcuaro. According to the research, high pH and alkalinity, categorize Lake Patrcuaro as an alkaline lake with its inorganic carbon components dominated be carbonates (30%) and bicarbonates (70%). In general, pH values ​​are similar in most locations, but the lowest value (pH = 8.8) was observed in the north basin. 90004 90002 90008 Note 90009: There are many reports that aquarists kept them in the range on 6.0-7.0 as well. Although it is not recommended. 90004 90002 In addition, Dwarf Mexican crayfish prefer to live in the water with high values ​​of TDS. 90004 90002 The temperature of the tank needs to be anywhere from 18 — 24 ° C (~ 65 ° F — 75 ° F). According to some studies, these crayfish can easily tolerate temperature from 15 — 31C (~ 59 ° F — 87 ° F). For example, they were even found in the pond where the temperature fluctuates from 31 to 37 C (~ 87 ° F — 98 ° F) during the year. 90004 90002 According to another study, where the three temperatures 18 ° ± 1 ° C, 22 ° ± 1 ° C and 26 ° ± 1 ° C were tested.Significant differences were found regarding female survival and viability, but not in the percentage of spawning. Biologists found that the increased viability was recorded at 26 ° C and the highest survival rate of females was recorded at 18 ° C. 90004 90002 As we can see, this is a very hardy animal, but regular 90008 water changes 90009 are vital to its optimal health. Installing the proper filtration system along with changing the water will ensure that your crayfish stays properly oxygenated.90004 90278 90008 Best Substrate for Dwarf Mexican crayfish 90009 90281 90002 Many decapod groups such as shrimps, crabs, and crayfish live in the bottom of both lotic and lentic areas in inland waters. Therefore, the substrate type can play a very important role for them. 90004 90002 During my research, I have found the study «Growth Performance and Substrate Preference of Juvenile Mexican Dwarf Orange Crayfish (Cambarellus patzcuarensis) in Different Substrate Types». Six different substrates were tested in this study.Total length and weight measurements of Dwarf Mexican crayfish were carried out biweekly during the 100-days experiment. 90004 90002 90287 Particle sizes of other substrates for pebble is 3-5 mm, sand is 800-1000 μm, calcite is 800-1000 μm with white color, and basalt is 300-500 μm with greyish black color. Particulates substrates (pebble, sand, basalt, and calcite) covered the bottom of aquaria in the layer of 0.5 cm. 90004 90002 90008 The results of the study: 90009 The results of the growth experiment indicate that Mexican dwarf orange crayfish gained significantly higher weight when raised on basalt substrates.Bare glass (control group) was the lowest among the other substrates. 90004 90002 According to the result of the substrate preference experiment, crayfish spent more time on basalt substrate when given a choice of substrates. These results pointed out that the type of substrate is an important parameter for growth performance and selection of life habitats on this species. 90004 90002 90008 90297 Note: 90009 In nature, Dwarf Mexican crayfish are found in lava sandy areas. So that the basalt is close to the natural substrate of this species with its small particles and greyish black color.90008 90009 90004 90278 90008 Filter and Dwarf Mexican crayfish 90009 90281 90002 Due to the small size of the offspring (the offspring of the Dwarf Mexican crayfish are very tiny (about 2 mm)), the filter intake should be covered with a sponge or net. Once again, basically, it is the same procedure as with baby shrimp. 90004 90002 90008 You can read my article «The Best Filtration System for Breeding Shrimp». 90009 90004 90002 Personally, I believe that the Matten filter will be the best option for the Dwarf Mexican crayfish.A large amount of surface area in those types of filters allows plenty of room for microorganisms to colonize. They will help keep the water clean, and the currents produced by the filter will not endanger the small baby crayfish. 90004 90019 90008 Driftwood, Rocks, Plants and Dwarf Mexican crayfish 90009 90022 90002 Driftwood, rock, and plants are essential parts to a successful shrimp tank. Well, with Dwarf Mexican crayfish they are not essential, they are crucial! 90004 90002 You have to provide lots of hiding places to prevent / reduce stress (during molting) and territorial battles.If the tank has a lot of secluded places, even in crowded tanks, it will be rare for any specimens to lose a pincer. Otherwise, they can seriously harm (or even kill) one another. 90004 90002 90008 You can read my article «Driftwood in Shrimp Tank» 90009. 90180 90008 You can read my article «Top 5 Plants for Your Shrimp Tank». 90009 90004 90002 Regardless of their hardiness, it will be better to 90008 acclimate them (read more about it) 90009. 90008 90009 90008 90009 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008 Molting 90009 90022 90002 The same as a shrimp, Dwarf Mexican crayfish need to shed their exoskeleton in order to grow in size and also regrow any lost limbs.An adult crayfish only needs to shed its skin up to five times a year whereas a juvenile crayfish will shed its exoskeleton every 7 to 10 days. 90004 90002 When the crayfish is in the molting process they will look for a place to hide, either under a shell or in a crack between rocks at the bottom of the tank. The reason they like to stay hidden during this process is that they are completely defenseless until their skeleton fully hardens. 90004 90002 90008 You can read more about molting in my article «Crayfish and Molting Process».90009 90004 90019 90008 Feeding 90009 90008 Dwarf Mexican Crayfish 90009 90022 90002 Dwarf Mexican crayfish almost always spend their time scavenging for food and wandering around their habitat. They are omnivores and prefer organic food. These species enjoy blackworms, crushed snails, earthworms, and brine shrimp. As a special treat, you can feed your Dwarf Mexican crayfish Algae wafers, which is something they seem to really enjoy. 90004 90002 Keep in mind these little critters are also scavengers and will eat basically anything you throw in the tank.You will want to feed your crayfish bottom-dwelling live food along with sinking pellets of any brand. 90004 90002 Surprisingly crayfish also enjoy vegetables such as shelled peas and zucchini. 90008 You can read my article «How to Blanch Cucumbers and Zucchini for Shrimp, Snails, and Fish the Right Way.» 90009 90004 90002 Supplement their diet and make sure they get enough calcium (for the exoskeleton) by regularly feeding specialized invert foods. 90004 90002 90008 Note 90009: Lots of aquarists noticed that snails and any meaty foods are preferred and it helps them grow much faster.Algae wafers, vegetables should only be a supplemental diet. The main diet needs to be meat (protein) anyway. 90004 90002 90008 Tip 90009: Color enhancing food such as 90008 Hikari Shrimp Cuisine 90009 90008, 90009 90008 Hikari Micro Wafers 90009, and 90008 Hikari Tropical Crab Cuisine (link to check the price on Amazon) 90009 can be a good option to go for if you want to maintain or improve that bright orange coloration. 90004 90002 90008 You can read my article «How to Enhance Shrimp Color?» 90009 90004 90019 90008 How Often to Feed Dwarf 90009 90008 Mexican 90009 90008 Crayfish? 90009 90022 90002 There is no easy answer to this question because it has to be a delicate balance with crayfish and teammates (fish or shrimp).90004 90002 What I want to say is that if you feed too much, you will risk to foul up the water and cause a lot of problems. On the other hand, it is absolutely important crawfish be fed enough not to go after the shrimp or fish and the shrimp need to be fed enough to grow the colony. 90004 90019 90008 Breeding 90009 90008 Dwarf Mexican Crayfish 90009 90022 90278 90008 Mating 90009 90281 90002 90410 If you are one of the many Dwarf Mexican crayfish owners who want to breed their colony, it is not as hard as it would seem.Breeding them is considered such an easy process because not much intervention is needed on the caretakers part. The crayfish will do the work all on their own. 90004 90002 First of all, you need to make sure you have at least one male and one female in your tank. When breeding is initiated, the male flips over and pins down the female and deposits sperm near her sperm receptacle. 90004 90002 90008 Note 90009: If you wait and watch closely the male crayfish will pounce on top of the female crayfish placing sperm inside of what’s referred to as the female’s sperm receptacle.The female crayfish will then fold over her tail, placing it under her body so that she may fertilize her eggs. 90004 90002 According to the study about the Dwarf Mexican crayfish, a higher percentage of spawning at 18 C occurred with 89%. At 18 C and 22 C, the females spawned on more than one occasion. The spawning rate was lower at 22 C and 26 C (about 66.67%). 90004 90002 90008 Note # 2: 90009 It is worth mentioning that it was found that the initial size of reproduction and spawning in Dwarf Mexican crayfish (Cambarellus patzcuarensis) was 23 — 25 mm (~ 1 inch), which coincides with Cambarellus montezumae (another dwarf species).They reach maturity at around 2.5 — 3 months old. 90004 90278 90008 Eggs 90009 90281 90002 90429 Female Dwarf Mexican crayfish can usually have anywhere between 20 and 40 eggs. In some cases, big females can carry up to 60 eggs. The female uses her appendages to keep the eggs clean from dirt and well oxygenated. Her body also keeps the eggs protected from predators and other dangers in her habitat. 90004 90002 Keep in mind that the temperature plays a huge role here as well. For example, biologists noticed that females retain on average between 13.92 and 21.69 eggs. The lowest was found at 26 C (79F) and the largest number was presented by females at 18 C (64F). It usually takes from 3 — 4 weeks to hatch depending on temperature. 90004 90002 Regarding the loss of eggs, researchers attributed it to the individual factor (experience). Young ovigerous females lose a large number of eggs for their lack of care, while females with experience in handling of their spawning, under similar conditions, present a lower loss. 90004 90002 In addition, egg loss is proportional to the size of the Dwarf Mexican crayfish, so small females lose more eggs than females larger size.90004 90278 90008 Hatching Day and Baby Dwarf Mexican Crayfish 90009 90281 90002 90442 If you can see dark spots (developing eyes) on the eggs it means that they are about to hatch. 90004 90002 After hatching, they can still cling onto the mother in their curled up position and stay with her for a few days. Until their shells are hard enough for them to swim off on their own they are completely defenseless. Even more, at this stage of life baby Dwarf Mexican crayfish can only wiggling but unable to actually get up and walk.90004 90002 Baby Dwarf Mexican crayfish can basically be fed the same thing you feed the adults, it just needs to be in smaller proportions. Sometimes (during first few days) the hatchlings will scavenge for their food at the bottom of the tank along with their mother. 90004 90002 The females usually do not attack their babies in the first few days after hatching. However, this is not a rule. Therefore, ideally, you need to isolate them (for example, in a little plastic container inside the tank to protect them from the adults).Unfortunately, there are many reports about people who keep their babies with adult Dwarf crayfish and get poor success in keeping them alive. 90008 90009 90004 90278 90008 Important to know about Dwarf crayfish babies 90009 90281 90002 DO NOT keep different generations together. Dwarf crayfish babies are also very aggressive. Especially, larger ones to smaller ones. Even with a small size difference, they will not hesitate to catch smaller ones and kill them. Only babies of similar size can be kept relatively safe together.90004 90002 At the early stages, you need to feed Dwarf crayfish babies daily. Otherwise, they will die due to hunger or aggression. As long as they are well-fed, they will not attack each other to cannibalize. 90004 90002 Of course, you will see mock fight anyway but they jump away almost immediately. 90004 90002 90008 Tip 90009: If your crayfish eggs have hatched and fall off the mother, scoop them up gently and keep them in a safe place inside the tank. There is a possibility that it will develop.90004 90002 You can build DIY egg tumbler to increase the chances of survival. 90008 Read my article to learn more about how to do that «Save the Eggs from a Dead Shrimp». 90009 90004 90278 90008 Dwarf Mexican Crayfish and 90009 90008 Cannibalization 90009 90281 90002 I have already mentioned it before but one of the issues with keeping them is cannibalization. Therefore, DO NOT overestimate how many you can keep or Dwarf Mexican Crayfish will sort that out for you. 90004 90002 Hatchlings and juveniles should be removed into their own containers, as these often got eaten by adults.Once they are about 1.5-2 cm (2/3 inch), you can set them with the adults. It should be 90008 relatively 90009 safe by then for them to be not seen as free food. 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008 and Fish T 90009 90008 ankmates 90009 90022 90002 If you want to keep your crayfish from becoming prey it is recommended that no aggressive fish be kept in the same tank and the habitat be kept as peaceful as possible. You will want to have lots of shells, gravel, and other things at the bottom of your tank for the crayfish to hide in.Having a good place for the crayfish to hide is not only important to the molting and breeding process but will make their environment feel more like home. 90004 90002 Aquarists noticed that Dwarf Mexican Crayfish have a tendency to react defensively. They can behave aggressively towards a fish if they feel threatened. They do not have the capability to kill most fish, but they will not hesitate to take chunks of fins if they feel threatened. 90004 90002 In most guides about Dwarf Mexican Crayfish, you will read that they are compatible with anything and everything.However, it is very important to mention that each Dwarf Mexican Crayfish has individual personality meaning that some people have had crayfish successfully in community tanks while others have had disastrous results. 90004 90002 In general, they do not limit your options as their bigger cousins ​​do. Even small fish, snails, and other water plants can be housed with the Dwarf Mexican Crayfish. For example, they can live together with guppies, mollies, boraras, dwarf swordtails, and snails, and even the offspring of these species survive.Only ill and weak specimens are removed by the crayfish, helping to preserve the health of the entire community. 90004 90002 If your tank has a big fish do not expect to see your crayfish during the day. They will spend the daytime hours hiding from danger. Make sure the hiding places are too small for the big fish to access. 90004 90019 90008 Dwarf Mexican Crayfish 90009 90008, Shrimp and Snail Tankmates 90009 90022 90002 Frankly saying, you will get mixed answers on this because it is going to depend on the individual.I have read that people manage to keep Dwarf Mexican Crayfish with Dwarf shrimp and they were doing just fine. 90004 90002 Personally, I do not think that this is a good idea to keep them together if you are planning to breed your dwarf shrimp. Dwarf Mexican Crayfish can easily overpower shrimp because they are almost twice as big (with few exceptions, like Amano shrimp or Bamboo shrimp). In addition, any molting shrimp is an easy meal for a crayfish. If crayfish gets hold of a shrimp, the shrimp usually does not have any chances.90004 90002 Of course, we can look at this from another angle. Healthy shrimp are too fast for them. So, if they caught a shrimp I would guess it was ill, slow, genetically weak or simply too stupid. Therefore, it must go anyway. Basically, they will do culling for you. 90004 90002 90008 Read more about «Culling Shrimp. Selective Breeding. » 90009 90004 90002 Even baby Dwarf Mexican Crayfish can try to catch baby shrimp. Therefore, keeping them together with dwarf shrimp should be avoided.Nonetheless, if you agree to lose one or two shrimp here and there you are good to try. 90004 90002 90008 Tip 90009: They will not go after the shrimp if you feed them (at least it will reduce the chances). 90180 90008 Note 90009: Dwarf Mexican Crayfish can eat 90008 bladder (pest) snails (read the guide about them) 90009. Unfortunately, they can also nip off the antennae of larger snails. 90004 90019 90008 In Conclusion 90009 90022 90002 Nowadays, keeping an aquarium is a popular hobby worldwide.The interest in crayfish is increasing. Aquarists interest in crayfish species for many causes such as their interesting behaviors, individual personalities, attractive colors, and patterns. 90004 90002 Adding Dwarf Mexican Crayfish to your aquarium is a great idea, only if you are ready to fulfill their needs and provide a certain level of attention and care. They can be very peaceful in a community tank when they are satisfied and contented. In this case, they are shrimp, fish, plants friendly (almost), and compatible with anything and everything.90004 90002 All in all, Dwarf Mexican Crayfish are extremely amusing and fun to watch. 90004 90019 Related articles: 90022 90002 90008 Introduction to the Crayfish Care — Setup, Diet, and Facts 90180 How to Set Up a Crayfish Tank 90009 90180 90008 Can You Keep Crayfish With Other Fish? 90009 90008 90180 90009 90008 Brazos Dwarf Crayfish — Detailed Guide: Care, Diet, and Breeding 90009 90004 .90000 Crayfish — The Care, Feeding and Breeding of Freshwater Crayfish (Crawfish) 90001 90002 90003 Crayfish Stats 90004 90005 90003 Minimum Tank Size: 5 Gallons 90004 90005 90003 Care Level: Easy 90004 90005 90003 Water Conditions: PH 6.5-8 and Medium Hard to Very Hard 90004 90005 90003 Temperature: 65-75 F (18-23 C) 90004 90005 90003 Maximum Size: 3 inches (8 centimetres) 90004 90020 90002 90003 Introduction 90004 90020 90002 For anyone looking for a quirky and interesting pet, the freshwater crayfish is an excellent choice.. They are easy to care for, extremely hardy, and often interact with their owners. While crayfish are definitely not safe for a community fish tank, it is well worth having a tank dedicated to crayfish just to enjoy their antics. 90020 90002 When choosing a freshwater crayfish, it’s important to know that there are well over 100 species of crayfish from around the world. While most crayfish require cool water, some require tropical temperatures to thrive. Before purchasing a crayfish, a owner should do some research to determine the crayfish species needs.If a crayfish is well cared for, they will usually live 2-3 years, with some species living even longer. 90020 90002 90003 Housing 90004 90020 90002 A single crayfish can be kept in a relatively small aquarium. A 5 to 10 gallon aquarium is usually more than adequate, especially if regular water changes are provided. Crayfish are notorious for hiding their food, and will often have a stash hidden away in a cave or flower-pot. On top of that, they are also messy eaters, and when coupled with hidden food, water quality can quickly decline.When doing water changes, you should always check for a stash of food in any of the crayfish hiding spots. 90020 90002 If more than one crayfish is going to be housed in a tank, then a minimum of 20 gallons need to be provided. Crayfish are cannibalistic by nature, and when a crayfish moults it is nearly defenseless until its shell hardens again. During this time, it will hide for a few days, so do not be too alarmed if a crayfish disappears for a up to a week at a time. Because of this, it is very important to provide numerous hiding places and enough space for each crayfish in the aquarium — unless someone wants their crayfish to become an expensive meal for the other tank inhabitants.90020 90002 It becomes much trickier when it comes to housing crayfish with fish. There are many accounts of people successfully keeping crayfish and fish together, but given enough time, either the fish or the crayfish is going to be eaten. There is nothing worse than losing a large, expensive fish to a crayfish over the course of a night. Or alternatively, finding crayfish parts scattered across an aquarium, with a very full looking fish. While a person can certainly try to keep fish and crayfish together, it ends badly more often than not.90020 90002 The filtration for a crayfish should usually be a HOB (Hang-on-back) filter. While a sponge filter is cheaper than an HOB filter, the air line leading out of the tank gives the crayfish a perfect escape route. If you leave the crayfish alone long enough, you will eventually see a crayfish running around on the floor of your fish room. 90020 90002 90003 Feeding 90004 90020 90002 A crayfish’s main diet should be comprised of sinking Shrimp Pellets, but they also enjoy some green vegetables and frozen foods in their diet.They are not picky when it comes to green vegetables and can be offered cabbage leafs, zucchini medallions and shelled peas. As for frozen foods, they happily accept small portions of frozen fish, daphnia, bloods worms and brine shrimp. 90020 90002 A word of warning — crayfish love aquatic plants and will eat any that are put in the tank with them. An adult crayfish can strip a heavily planted aquarium bare in a matter of days. So while it may be a good place to dispose of unwanted plant clippings, you should never put any plants in their aquarium that are not replaceable.90020 90002 90003 Breeding 90004 90020 90002 Most species of crayfish will breed at any time in the home aquarium, though feeding high quality foods and keeping the water pristine will help trigger breeding behavior. Crayfish can be frustratingly hard to sex for someone new to keeping them, but the easiest way is to look at the swimmerets. The males will have swimmerets that extend past the back legs, while the females will not have any past the back legs. 90020 90002 When mating begins, the male deposits a sack of sperm on the female who then passes her eggs through the sperm to fertilize them.After the eggs have been fertilized, they are then kept under the tail by the female who should be placed in a tank on her own at this point. 90020 90002 After around four weeks, the eggs will hatch and the young crayfish will emerge. The female crayfish will take care of the young for a short period of time, but should be removed after a few days to prevent the fry from being eaten. A large nursery tank is required if any number of crayfish fry are expected to survive as they are extremely cannibalistic like their parents.90020 90002 The baby crayfish can be feed blanched cabbage leafs or lettuce leaves, and also consume detritus in the tank. As the crayfish grow, the larger ones should be removed from the tank as they will feed voraciously on the smaller crayfish. 90020 .