Comparison of
larval performance between Thai and Vietnamese freshwater giant prawn, Macrobrachium
rosenbergii (de Man): a preliminary study
A.N. Bart, P.T. Yen-2003
Aquaculture
Research, 34(15):
1453-1458
Abstract:
This study compared the performance of
larvae of giant freshwater prawn (Macrobrachium rosenbergii) from
Thailand and Vietnam. Thai broods were collected from a farm and Vietnamese
broods were collected from a river. Larvae from these two sources were
raised in identical environments, and their rates of development and
survival as well as their ability to withstand environmental stresses were
assessed. The first postlarval stage was observed in both strains on day 22.
All larvae (100%) from Thai broods completed metamorphosis by day 36, but
only 89% of the Vietnam strain completed metamorphosis by day 45. The stages
of development were more uniform in larvae from the Thai stock than the
Vietnamese stock. Survival differences were observed within the first week
(92% in the Thai group vs. 55% in the Vietnamese group). These differences
were most pronounced beginning in week 5 (52% and 16% respectively) and week
7 (33% and 2% respectively). No clear difference was found in brood size and
fecundity between the two groups. No difference in survival was observed
between the two groups of larvae challenged with salinity, oxygen or
formalin. Differential development rates of larvae in the same batch would
naturally create conditions favourable for cannibalism and impaired ability
to capture food. The earlier and more uniform rate of development, and
subsequent higher rate of survival of Thai stock compared with the
Vietnamese wild stock is suggested to be due to inadvertent selection in the
domesticated stock.
(Aquaculture and Aquatic Resources
Management, Asian Institute of Technology, Box 4, Klong Luang, Pathumthani
12120, Thailand. E-mail: bart@ait.ac.th)