ARTIFICIAL-INSEMINATION IN TURBOT (SCOPHTHALMUS-MAXIMUS) - DETERMINATION OF THE OPTIMAL SPERM TO EGG RATIO AND TIME OF GAMETE CONTACT

In high-quality batches of eggs (mean egg viability rate 89.6%), fertilization success (FS = number of 4-cell-stage eggs/number of viable eggs) was maximal when the ratio of spermatozoa to egg was above 6 X 10(3). For lower ratios, FS decreased and became highly variable. In lower-quality batches of eggs (mean egg viability rates 72.0 and 75.9%), FS was variable even for the highest sperm to egg ratios, For the ratio of 1.5 X 10(3) spermatozoa per egg, the occurrence of maximum FS in relation to increasing contact time between gametes was scattered and mainly recorded after 2 and 3 min. For the ratio of 6 X 10(3) spermatozoa per egg, maximum FS was mainly observed after a contact of 1 min between gametes. In commercial production, a minimum ratio of 6 X 10(3) spermatozoa per egg and a contact time between gametes of 3 min is recommended for the artificial insemination of turbot eggs.