TITLE:
Spawning, intracapsular development and production potential of viable juveniles of a murex Chicoreus virgineus var. ponderosa Sowerby under laboratory conditions
AUTHORS:
I. Jagadis, K. Shunmugasundaram, Md. Sathakkathulla, T. Mohanraj
KEYWORDS:
Spawning; Intra Capsular Development; Muricids; Chicoreus Spp
JOURNAL NAME:
Agricultural Sciences,
Vol.4 No.5,
May
30,
2013
ABSTRACT:
Muricids
are commercially important gastropods and are exploited primarily for shell
craft industries. They also occupy a niche in ornamental keeping. Studies on
the larval development of muricids in Indian waters are few. Hence, an attempt
was made to study with a focus on the optimum requirements for captive brood
maintenance; regional variation in egg laying, intracapsular development and to
estimate production potential of individual brooder (the length/ weight ranged
from 80 -110 mm/49 -169 g (average 94.875 ± 3.980 mm/111.625 ± 14.870 g) of Chicoreus virgineus var. ponderosa collected off Tuticorin coast,
Gulf of Mannar. Experimental airlift water circulation system fitted in 1 t FRP
tanks having an overturn of 300% water is found suitable for long term maintenance
and maturation of brooders with near cent percent survival over a year.
Spontaneous breeding commenced from June ’09. Eggs cases were ‘vase’ shaped and
measured 1.2 -1.5 cm in height. Egg case numbers varied between 110 and 140 and
got reduced to 10 -40 during October and increased in Nov & December. Number
of eggs within the egg case was highly variable ranging from 100 -380. Eggs were
spherical, embedded in jelly mass within the egg case and measured 510 -608 μ
(578 μ). Intra capsular development is detailed and compared with the earlier
report on this species from other areas of Indian coast. Development took
nearly 20 days and only few free living juveniles measuring between 1.7 -1.9 mm
emerged and the rest of the eggs have functioned as “Nurse eggs”. Average net
production potential of a single viable egg case was estimated to be 6.7 nos
for Chicoreus virgineus var. ponderosa of Tuticorin coast of Gulf of
Mannar.