Studies on the status and feasibility of culturing spiral Babylon, Babylonia spirata in Tuticorin, Southeastern India

The fishing villages, Tharuvaikulam, Vellapatti, Thirespuram and Harbour Beach in Tuticorin coast of Southeastern India are identified as Babylonia spirata landing centers and studied for a period of 3 years (October 2002-September 2005). The landings were exclusively as by-catches in crab nets and higher landings were observed during the pre-monsoon period. 200 brooders collected from wild for culture experiments and maintained in the laboratory were sexed and measured for their length, width, weight and opercula width. The male: female ratio was observed to be 1: 1.5. Males had an average length of 45.4mm and weight of 25.36g, while the females measured 47.4mm in length and 28.62g in weight. The average length of the egg capsules was 18.4±2.7mm (mean±SD). The adults laid eggs in the laboratory and veliger larvae were hatched. The larvae were fed with different types of algal feeds such as monocultures of Isochrysis, Chaetoceros and mixed cultures of Isochrysis: Chaetoceros and Pavlova: Chaetoceros in 2: 1 ratio respectively. Better survival of 2.9% was observed in the veliger larvae fed with mixed culture of Isochrysis and Chaetoceros. Metamorphosis occurred from veligers to juveniles and the initial shell length was 1.7mm, shell width 1.3mm and weight 0.01g. After 390 days, the shell length was 22.5mm, width 19.6mm and weight 4.25g. The survival was 2.3%. The gut contents were analyzed in the animals collected from the wild and the animals cultured in the laboratory. Total Heterotrophic Bacterial count was more in the case of wild compared to the ones cultured (105×10^2 CFU/g and 27×10^2 CFU/g respectively). Vibrios, Salmonella spp. and Micrococcus spp. were absent in laboratory cultured animals while they were present in wild ones at the levels of 7×10^2 CFU/g (Vibrios) and 3×10^2 CFU/g (Micrococcus spp.). Both the samples showed the presence of Escherichia coli (3 MPN/100g). The present study provides suitable hatchery technology for culture of B. spirata