From: Glenn Schipp <schippg@ozemail.com.au>
To: AQUA-L@LISTSERV.ifmt.nf.ca
MUD CRAB BROODSTOCK SPAWNING PROBLEMS
QUESTION:
I am a MSc. student carrying out a research relating to Mud Crab (Scylla serrata) breeding. Mud Crab broodstocks were cultured in 1-ton tanks and fed with fish, shrimp, mollusks. Sea water was exchanged every day. Water quality is about 30ppt in salinity, 26-30 C in temperature, over 6ppm in DO. However, a problem is that when the broodstocks spawned, from 50-100% eggs did not stick to pleopods of the abdomen of the female but fell on the bottom of the tanks.
What is the cause of the problem?
Tran Ngoc Hai
Universiti Pertanian Malaysia Terengganu
21031, Kuala Terengganu, Malaysia
Email: hai@umpt.edu.my
ANSWER:
Your problem may be due either to poor fertilisation or to bacterial/
protozoan infection. Solution to the first problem is to carefully select
good quality female spawners. For the second problem we recommend newly collected females are bathed in 100 ppm formalin for 1 hour.
Glenn Schipp
Darwin Aquaculture Centre
Department of Primary Industry and Fisheries
GPO Box 990
Darwin NT 0801
AUSTRALIA
phone: +61 8 89 99 4362
fax: +61 8 89 99 4193
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