Journal of the Marine Biological Association of India

Growth rate of the brine shrimp Artemia parthenogenetica at five different concentrations of mixed algal feed

Volume 48 Issue 1

C.Govindasamy and L.Kannan

Abstract

The growth rate, in the brine-shrimp, Artetnia partlzenogenetira fed on Isochrysis galbana + Tetraselmis gracilaria (I:l) at concentrations ranging from 3- 20 mg C 1^-1 day^-1 for 14 days at 28 ± 4⁰C and 60%o salinity, was determined. The individual body length increased exponentially with age to a point of inflection before the growth rate gradually decreased when the animals reached the pre-adult stage. The growth was strongly influenced by the food concentration. The essential growth rates (10.45 ± 0.044 mm and 11.94 ± 0.005 mm) increased with increasing food concentration and reached the maximum level at an algal concentration of 10 and 15 mg C I^-1  day^-1. At lowest concentration (3 and 5 mg C 1^-1 day^-1) the length attained was 7.72 & 0.001mm and 9.12 ± 0.005 mm at post- metanauplius stage 111. The growth, when fed at the higher food concentrations (10, 15 and 20 rng C I^-1 day^-1, increased exponentially, thereafter it gradually leveled off after 14 days of culture indicating a "Sigmoidal" type growth curve. Specific growth rate started to increase with an increasing food concentration and the highest (2.99 mm day - I ) was obtained at day 6 for animal grown at maximum food concentrations (20 mg C 1^-1 day^-1). Minimum food concentration required for maximum specific growth rate was 10 mg C ^-1 day^-1, and a further increase in the food availability did not result in a higher growth rate. Food concentrations below 10 mg C I^-1 resulted in reduction in growth rate. Higher concentrations of food had no effect, but lower concentration reduce both growth and stages.

Keywords

Food concentrations - growth rate - specific growth, brine shrimp, Artemia parthenogenetica

Date : 30-06-2006