Echinoid eggs with sizes greater than the gonopore experience strain resulting from compression during spawning, which can damage them affecting fertilization. The aim of this study was to describe gamete characteristics and analyse aspects related to egg strain during spawning of Pseudechinus magellanicus from Golfo Nuevo, Patagonia, Argentina. Mean fresh egg diameter observed was 122 μm with an additional jelly coat of 49 μm. The relationship between gonopore sizes and maximum test diameter showed a positive correlation but egg size did not vary with test diameter, as seen in other sea urchins, indicative of egg strain during spawning. Egg strain calculated from the relationship between egg size and gonopore size was 0.47-0. Eggs of small individuals (<15 mm test diameter) were the most affected by this strain. The egg jelly coat observed in P. magellanicus could protect eggs from strain and shear stress during spawning. Rev. Biol. Trop. 56 (Suppl. 3): 335-339. Epub 2009 January 05.
Keywords: sea urchin, Pseudechinus magellanicus, spawning, egg strain, jelly coat