Utilization of yolk reserves by embryos and paralarvae of Octopus vulgaris at 14ºC and 18ºC

Abstract

Embryonic development of O. vulgaris has been thoroughly described in literature (Naef 1928, Iglesias 2004). Naef (1928) described twenty different stages of embryonic development, classified according to their morphological characteristics. The inner yolk sac begins in the embryo at the Naefs stage XV of embryonic development. According to Boletzky (2010), this yolk mass passes through the bloodstream into the digestive system in order to form a nutritive reserve (the inner yolk sac) which provides the newly born paralarvae the possibility to obtain the energy required during the first days of life, although Octopus paralarvae begin to feed immediately after hatching (Iglesias et al, 2006). The effect of temperature on the embryonic development of cephalopods is well documented (Boletzky, 1987). However, with a few exceptions there are no data on the effect of temperature on survival and rate of yolk utilization in cephalopod hatchlings. The main goal of this work was to describe the use of outer yolk and its transference to the inner yolk sac during the last stages of the embryonic development of O. vulgaris, as well as the use of inner yolk by unfed paralarvae during the first 4 days at 14ºC and 18ºC and how this fact affect on the control of energy expenditure, growth and weight loss of the paralarvae.