Role of temperature variation in larval growth and post-larval production of Macrobrachium malcolmsonii (H. Milne Edwards)

摘要

Experiments on larval rearing of M. malcolmsonii were conducted from August to November 1992 under 3 different conditions: (i) under partially shaded (top) yard with exposure to natural conditions, (ii) in a closed room where ambient temperature varied according to seasons or (iii) in a temperature-controlled room, in 300-litre tanks employing an air-lift biofilter recirculatory system. Stocking density was 100 larvae/litre in each tank. Larvae were fed on Artemia nauplii twice daily for 2 weeks after which egg custard and mussel meat were fed 4 times daily until the end of the study. Under the first condition, the ambient temperature fluctuated between 18-29deg C averaging 25.80±2.30degree C and larvae did not grow well, with 102-118 postlarvae surviving.The first post-larvae appeared between 69 and 74 days and it took 98-116 days for the whole batch to metamorphose into postlarvae. Under the second condition, with an ambient temperature of 24-28degree C and average of 27.00±1.50degree C, growth was slow. The first postlarvae appeared between day 39 and 49 and total postlarvae production was 2700-3291 (9.00-10.97%) after 70-80 days of rearing. Better results were obtained under controlled conditions at an ambient temperature of 28-30degree C and average of 29.20±0.60degree C. First postlarvae appeared between day 25 and 41 and total production ranged from 5197 to 8832 after 55 to 60 days of rearing with recovery of 17.32-29.44% post-larvae.