Abstract

During paralarval development of the octopus Robsonella fontaniana, the mantle size is reduced in proportion to the total octopus length, whereas the organs more directly involved in catching prey tend to increase in direct proportion to the total length. A morphomet-ric and gravimetric study of R.fontaniana embryos was made in order to determine whether the morphometric trends and exponential growth rates observed in the planktonic and benthic phases begin during the embryonic development. Seven clutches, sampled during different seasons of the year, were studied under controlled conditions until hatching of the planktonic paralarvae. Yolk reserves and protein content in the perivitelline liquid were quantified to determine how the yolk absorption and the consumption of perivitelline protein are modulated during embryonic development. Results demonstrate that during embryonic development the growth rate for total length, mantle length, and arm length is exponential, indicating that the type of growth described for paralarvae and juveniles begins during embryonic life. The morphometric changes and growth are related to an exponential reduction of egg yolk and a linear consumption of perivitelline protein.