Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1905

Rafael Oltra and Rafael Todoli; Effect of temperature, salinity and food level on the life history traits of the marine rotifer Synchaeta cecilia valentina, n. subsp. J.Plankton Research 19(6):693-702, 1997

Reprint

In File

Notes

A strain of the marine rotifer Synchaeta cecilia valentina, n. subsp., isolated from the Hondo of Elche Spanish Mediterranean coastal lagoon at 22 0/00 salinity, was cultured in the laboratory in 20 ml test tubes and fed with the alga Tetraselmis suecica. The effect of two temperatures (20 and 24 degrees C), four salinities (20, 25, 30 and 37 0/00) and two food levels (15,000 and 24,000 cells ml-1) on the life history traits of this rotifer were studied in life tables performed with replicated individual cultures. Temperature and salinity had a significant negative effect (P<0.001) on the average lifespan (LS) and on the number of offspring per female (Ro). The effect of food level on LS is unclear, whereas Ro is greater at 20 degrees C with the lower concentration of algae and at 24 degrees C with the higher algal concentration. The maximum values of LS and Ro, 5.6 days and 9.2 offspring per female, respectively, were recorded at 20 degrees C, 25 0/00 salinity and low food concentration. There is also a clear negative effect on the intrinsic growth rate (r) due to salinity. The effect of temperature depends on the food level and, as occurs with Ro, the maximum values of (r) occur with the lower algal concentration at 20 degrees C, whereas at 24 degrees C they are obtained with the higher algal concentration. These (r) values, from 1.04 to 1.10 day-1, were reached at 24 degrees C, salinities of 20-25 0/00 and with high food concentration.