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Experiments on the Respiration and in situ Development of Baltic Herring ( Clupea harengus L.) Eggs

1985; Wiley; Volume: 70; Issue: 1 Linguagem: Inglês

10.1002/iroh.19850700108

0020-9309

E Braum,

Aquaculture Nutrition and Growth

Abstract A primary blastodise develops 2 hours and 40 minutes after artifical fertilization at 8 0/00 C and 15 0/100 S. The egg then begins embryonic development. When incubated in water with the oxygen concentration reduced to 50 % or 15 % saturation, the oxygen consumption of the eggs decreased to 73 % or 41 % of normal, respectively. For the in situ experiments, eggs and sperm taken from living fishes were spread on plexiglas plates in a way that monolayers adhered to the surface. The plates were then moored to buoys at two depths in a spawning area at Pötenitzer Wiek near Travemünde. Egg mortality increased with the duration of incubation. About 90 % of the spring spawn died before hatching, but only a 10 % mortality occurred among those spawned in autumn. Scanning electron microscope examination revealed structural changes on the egg surfaces caused by bacteria and particles of sediment. The role for survival of the pattern formed by the eggs as they adhere to the surface is discussed.