A Note on the Development of Eggs and Larvae of the Bogue, Boops Boops

Extract

An opportunity was taken to carry out the artificial fertilization and incubation at different temperatures of eggs of the bogue, Boops boops (Linnaeus, 1758) during a cruise on R.V. 'Cirolana' organized by the Fisheries Laboratory, Lowestoft. Adult fish for use in the experiment were obtained by bottom trawling in 165 m depth of water at 43° 44' N02° 44' W on 10 May 1980 between 0449 and 0549 h GMT. The bottom temperature at the trawling position was estimated to be ~ 11 · 8 °C, based on measurements made at nearby stations. Eggs and milt from several males and females were added to a container of sea waterheld at approximately 11 °C; after 1 h the fertilized eggs were transferred as four separate subsamples each of approximately too eggs to clean sea water in the incubation beakers. Thesebeakers were then gradually acclimatized over a period of 2 h to the incubation temperatures of80, 131, 182 and 22·8°C.

At all temperatures mortality was high during early embryonic development. At 228 °C all eggs were dead after 9J h of incubation at which time some of these specimens had formed a blastoderm cap, but with no sign of overgrowth of the yolk. In a few of the eggs held at 80 °C development proceeded normally until immediately before closure of the blastopore (~ 106 h after ferilization) when irregular vacuoles were seen in the area around the blastopore and development was disrupted; after 112 h of incubation all eggs held at 80 °C were dead.