alexa Biology of early life stages in cephalopod molluscs.
Environmental Sciences

Environmental Sciences

Journal of Biodiversity & Endangered Species

Author(s): von Boletzky S, von Boletzky S

Abstract Share this page

Abstract Recent literature on embryonic and post-embryonic development, biology and behavioural ecology of juvenile cephalopods is reviewed. Emphasis is placed on biological processes. Life-history patterns and phylogenetic systematics, which are important for a proper understanding of the evolutionary history of the cephalopods, are only briefly touched upon. Egg sizes in cephalopods range from less than 1 mm to about 30 mm in diameter, so the hatchlings emerging from the largest eggs are bigger than the adults of pygmy squid, the smallest known cephalopods. Developmental durations from spawning to hatching range from a few days (for very small eggs developing at high temperatures) to one or possibly several years (for very large eggs developing at low temperatures). Such important differences notwithstanding, the morphogenetic processes are very similar in all cephalopod embryos, the major variant being the size of the so-called outer yolk sac, which may be rudimentary in extremely small embryos. Several questions concerning the timing of hatching in relation to the developmental stage attained, especially in terms of yok absorption, need clarification. These questions concern the elimination of the transient closure of the mouth, the final differentiation of digestive gland cells, and the removal of the tranquilliser effect of the perivitelline fluid necessary for the onset of the hatching behaviour. Cephalopod hatchlings are active predators. They refine their behavioural repertoires by learning from individual experience in dealing with prey and would-be predators. There is no truly larval phase, and the ecologically defined term paralarva should be used with caution. Given the considerable resource potential of cephalopods, investigations into dispersal and recruitment are of particular interest to fishery biology, but they are also important for ecological biogeography. The related studies of feeding and growth involve field sampling and tentative age determination of caught specimens, in combination with laboratory studies to test food quality, measure feeding rates, and validation of periodicities in accretional growth structures (e.g. "daily rings" in statoliths).
This article was published in Adv Mar Biol and referenced in Journal of Biodiversity & Endangered Species

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords