Malta Aquarist Society

 Who kills who ? I mean does the female kill the male or the other way round ?

 Generally the male because he's bigger but it can be the other way round if the female is bigger.

When I try to breed crayfish again I will keep them seperatly and when the female sheds its exoskeleton, I will introduce the male because thats the time when they mate. But you must keep an eye on them because the female is vulnerable to the male's attacks if she doesn't want to mate.

 Prosit Giann. I haven't seen this thread yet. Although I am not that interested in these creatures, but I read all the posts and saw all the photos you have posted. They were just great. This is the good thing about our Society that different members have different likings. Keep up the good work mate and keep us updated with your successes.

martin

An interesting paper has just been published in the journal Aquaculture Research Volume 40 Issue 11. This is the abstract...

Effect of combined photoperiod, water calcium concentration and pH on survival, growth, and moulting of juvenile crayfish (Procambarus clarkii ) cultured under laboratory conditions

Cai-Feng Yue 1 , Ting-Ting Wang 1 , Yu-Feng Wang 1 & Yu Peng 2

1 Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, China
2 College of Life Science, Hubei University, Wuhan, China
Correspondence: Y-F Wang, College of Life Science, Huazhong Normal University, Wuhan 430079, China. E-mail: yfengw@mail.ccnu.edu.cn

Copyright Journal Compilation © 2009 Blackwell Publishing Ltd

KEYWORDS
Procambarus clarkii • photoperiod • calcium • pH • growth • juvenile

ABSTRACT

The red swamp crayfish, Procambarus clarkii (Girard), is one of the most commonly farmed freshwater species in inland China due to its high market value and consumer demand. The aim of this study was to determine the optimum combinations of photoperiod, water calcium concentration and pH for juvenile survival, growth and moulting. In our orthogonal experiment, the three environmental factors were varied at three levels (photoperiod: 16L:8D, 12L:12D and 8L:16D; calcium concentration: 45.5, 65.5 and 85.5 mg L−1; and pH: 6.8, 7.8 and 8.8). Range analysis showed that the maximum survival of juvenile crayfish occurred at photoperiods of 16L:8D or 8L:16D, water calcium concentration of 45.5 mg L−1 and pH of 7.8; maximum weight gain at photoperiod 16L:8D, water calcium concentration 65.5 mg L−1 and pH 7.8; maximum length increase at photoperiod 16L:8D, water calcium concentration 65.5 mg L−1 and pH 7.8; and the highest moult frequency at photoperiod 12L:12D, water calcium concentration 65.5 mg L−1 and pH 7.8. Analysis of variance indicated that photoperiod, water calcium concentration and pH significantly influenced only the weight gain of juvenile crayfish (P<0.05). Taking growth into consideration, we suggest that a photoperiod of 16L:8D, calcium concentration of 65.5 mg L−1 and pH 7.8 might be optimal conditions for rearing juvenile P. clarkii.