Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO2 conditions in the perivitelline fluid (>3-fold higher pCO2 than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas 45Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes

Das Eingraben in Sand bei Sepiola und Sepietta (Mollusca, Cephalopoda)

Volume: 77Start Page: 536End Page: 54

SPAWNING BEHAVIOR INDEPENDENT OF EGG MATURITY IN A CUTTLEFISH SEPIA-OFFICINALIS

Volume: 17Start Page: 247End Page: 24

Encapsulation of Cephalopod Embryos - a Search for Functional Correlations

Volume: 4Start Page: 217End Page: 22

On eggs and embryos of cirromorph octopods

Six eggs and embryos of cirromorph octopods from different parts of the world are described. Differences in egg size and structure suggest that these specimens belong to at least five different species, none of which can be identified now. One differs markedly from all the others by having a large space filled with gelatinous material between the chorion and the outer, rigid egg case. The body shape of the embryo in this specimen is also distinctive. Only clearly recognizable embryos, all at advanced embryonic stages, have been taken into account. Features common to all specimens are described and discussed

Laboratory rearing of Sepiolinae (Mollusca: cephalopoda)

Five species of Sepiola were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola afteer 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12,5° to 20°C. A fairly constant size increase (2,5mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month