Effect of the microalga Pavlova lutheri (Droop) Hibberd cultured with agricultural fertilizers on the growth and survival of larvae and postlarvae of the mussel Mytilus edulis (L.)

Abstract

An evaluation was made of the growth and survival of Mytilus edulis larvae to metamorphosis, fed on Pavlova lutheri cultured with three nitrogen sources: two agricultural fertilizers (urea and ammonium sulphate) and laboratory-grade nitrate (medium f/2). In the larval stage, survival between trials was greater than 92.0%, whereas total survival was greater than 87.0% and there were no significant differences between the three treatments. Growth of larvae fed Pavlova lutheri cultured with ammonium sulphate and f/2 was the same during the first 20 days of larval development, except on days 6 and 10. Lesser growth occurred in the treatment with urea and there were significant differences relative to the other two treatments, except on day 20 when growth was the same as in the treatment with ammonium sulphate. Seed survival was better in the two treatments with agricultural fertilizers, with no differences between the two, than in the f/2 treatment, with significant differences relative to urea and ammonium sulphate. Better seed growth was obtained in the treatment with ammonium sulphate, whereas growth in the urea and f/2 treatments was similar and there were no significant differences between the two. The results indicate that urea and ammonium sulphate, especially the latter, can be considered good alternatives for use in the laboratory production of microalgae, reducing costs by 98.81% relative to f/2.