Reproduction in rare bathyal octopods Pteroctopus tetracirrhus and Scaeurgus unicirrhus (Cephalopoda: Octopoda) in the east Mediterranean as an apparent response to extremely oligotrophic deep seas

WOS: 000342260200007Reproductive patterns of two benthic bathyal octopods, Pteroctopus tetracirrhus and Scaeurgus unicirrhus have been studied in extremely nutrient-poor environment of the deep-sea Eastern Mediterranean. Both species were found to exhibit a reproductive tactics of producing eggs much larger than in the western part of the sea which likely results in larger hatchlings with higher viability. P. tetracirrhus exhibited a typical "deep-sea" spawning strategy of simultaneous maturation of a single batch of large eggs with atresia of excessive oocytes, whereas reproductive strategy of S. unicirrhus is particular for shelf octopodids: asynchronous maturation of numerous batches of small eggs with no obvious regulatory atresia. Existence of these two types of ovary development and utilisation of fecundity are closely related to two types of evolutionary stable reproductive strategies based on existence of either very large or very small eggs with a few species occupying the "intermediate" position. (C) 2014 Elsevier Ltd. All rights reserved.EBILTEM (Science and Technology Centre of Ege University)Ege University [2008/SUF/004]; Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108Y102]Authors sincerely thank the EBILTEM (Science and Technology Centre of Ege University) (Project no. 2008/SUF/004) and Technological Research Council of Turkey (TUBITAK, Project no. 108Y102) for financial support, both anonymous reviewers and Dr. Chingiz Nigmatullin for valuable comments, and Dr. Marta Soffker for improving English