Contribution à l'étude de la croissance de la fougère aquatique Salvinia molesta (Mitchell), Salviniaceae

The growth of the primary and the tertiary forms of the water fern Salvinia molesta was studied during 60 days in 0.06 m2 glass containers containing fresh water. The growth of this plant as a function of time is exponential. The two forms have growth rates statistically identical. The main daily growth rate, expressed in number of leaves, is equal to 6.40% per day for primary forms and 5.90% per day for tertiary form, with doubling time of 10.78 + 1.08 days and 11.64 + 0.15 days.

Influence of salinity on population growth of a rotifer, Brachionus plicatilis (Mullen)

The rotifer Brachionus plicatilis plays an important role in prawn hatcheries. It tolerates a wide range of salinities. The present experiments were conducted to find the optimum salinity for its mass culture. Experiments conducted on various ranges of salinities starting from 0 to 40 ppt at an interval of 5 ppt revealed that Brachionus plicatilis did not survive at salinities 0 and 40 ppt. Optimum salinity studies conducted at 5-15 ppt with an interval of 1 ppt showed that the production of 70 individuals/ml was highest at 10 ppt salinity and the doubling time ranged from 1.728 to 1.317 days.