Effect of Formaldehyde on the Gelatinous Zooplankton (Pleurobrachia pileus, Aurelia aurita) During Preservation

Authors: Erhan MUTLU

Abstract: The medusae, Aurelia aurita, and the cydipid ctenophoran, Pleurobrachia pileus, collected from the Black Sea were preserved in 2% borax-buffered formaldehyde solution for two months. Changes resulting from shrinkage and weight loss were calculated. Pleurobrachia pileus lost weight and shrunk more than Aurelia aurita. Factors for changes in body size and wet weight were calculated to be 1.45±0.03 (26±1.8% Standard deviation) and 4.6±0.4 (70±4%) for A. aurita and 3.5±0.03 (71±4%) and 54±2.4 (97±1%) for P. pileus, respectively. The rate of dissolution of A. aurita in formalin was found to be dependent on size groups. Covariance analysis showed that there was no significant difference in length-weight relationship between living and preserved A. aurita, but this was highly significant for P. pileus.

Keywords: Formaldehyde, preservation, jellyfish, ctenophore