Reproduction of Pelagia noctiluca in the central and northern Adriatic Sea

• Published in: Hydrobiologia Vol. 216-217; no. 1; pp. 197 - 202
• Main Authors: Rottini Sandrini, L., Avian, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: 01-06-1991
• Subjects: Marine; Pelagia noctiluca
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/BF00026462

The sequence of vitellogenesis as related to size increase of the oocytes of Pelagia noctiluca (Scyphozoa, Semaeostomeae) was examined to assess the influence of climatic factors on its reproductive period in the central and northern Adriatic Sea. From 1981 to 1985, 5 specimens with similar diameter were sampled each month. One ovary was excised from each individual and examined both with a videoanalyzer, to count the oocytes and to check their size distribution, and through histology to assess the stage of maturation in relation to the diameter. Oocytes of all stages were present in the ovaries of individuals down to a bell diameter of 3.5 cm. Thus reproduction occurs throughout the year in the central and north Adriatic Sea. However, the number of oocytes in different developmental stages in a gonad may range from a minimum value recorded in summer to two peaks in spring and autumn. The quantitative distribution is related to sea temperature and thus to metabolic rate, and to food availability.