Key Data for Keeping Marron

Temperature
Marron is intolerant of high water temperature. Marron grows at 12.5-24℃ and grows best at 24℃. However, above this temperature, Marron growth declines rapidly and mortalities occur at 30℃.


Dissolved Oxygen
Marron is intolerant of low oxygen level and becomes stressed when dissolved oxygen drops below 3ppm. The oxygen levels should be maintained at or above 6ppm.


Water Quality

pH
The water should be preferable alkaline ( pH 7.5-10.5). Marron is rarely found in acidic waters (pH below 7.0) where moulting and shell hardening problems occur.

Salinity
Marron will tolerate salinities up to 15ppt. However, low salinities are most suitable, as growth decreases when salinities are above 6-8ppt.


Reproduction
Marron may take 18-24 months to reach breeding age. Marron mates in early spring and, depending on the size of the female, she incubates 200-900 eggs for 12-16 weeks. A ratio of 1 male to every 3 females brings 75% female broodstock the incubation. Marron breeds only once a year. The juvenile will be released in early summer.


Growth
Marron can grow to 60-150g within 12 months and 100-300g within 24 months. Marron grows to 2kg.


Disease

Porcelain disease (White tail disease)
This disease is caused by a single-celled animal, microspordian, Thelohania. The crayfish, being an opaque or whitish blotched abdomen in the advanced phase, will die. The disease is transmitted through cannibalism of infected individuals. There is no known treatment for Thelohania. The disease may be managed by screening out and destroying animals, though the disease can not be easily detected in the early stage. Thelohania has not reported in Marron in Australia but in Japan thelohania may be in Marron.

Crayfish plague
Crayfish plague caused by fungus Aphanomyces astaci and originated in the United States spread to Europe and destroyed their crayfish stocks. The fungus is not present in Australia, but it is not known whether the fungus is present in Japan or not.

Parasites
A temnocephalan or an epistylis are found on the gill or shell. They are not actively harmful to Marron but they may cause the harm if there are too many. Temnocephalan or epistylis may be removed with salt baths. Dose: either 30 grams of salt (not table salt but sea salt or artificial sea salt) per liter of bath, for 2-3 minutes; or 10 grams per liter of bath, for 30 minutes.


Diet
Marron is primarily detritovore and its main sources of nutrition are the microbes (including bacteria and fungi) that break down leaf matter. Best growth rates are achieved with supplementary feeding.　Pelletized diet does not completely replace natural food sources as the sole source of nutrition for Marron.