Suchergebnisse

The fatty acid (FA) profile of wild Octopus vulgaris paralarvae of estimated age was individually analyzed for the very first time in order to establish a reference for comparison in rearing and nutritional studies. Age of each paralarvae was estimated by analysing daily increments on lateral hood surface of beaks. Wild paralarvae age ranged between 6 and 8 days and their FA composition resembled that from hatchlings produced under culture conditions. However, when compared with the FA composition of up to 20 days old cultured paralarvae described in the bibliography, some striking differences were found. Results showed higher levels of docosahexaenoic acid (22:6n − 3, DHA), lower contents of 18:1n − 9, 18:1n − 7 and 18:2n − 6 and negligible levels of 18:3n − 3 in wild paralarvae, when collated to reared one. These results seem to indicate that preys/diets supplied to cultured paralarvae fail to resemble paralarval natural composition and as a result do not fulfil their FA requirement. The individual applied technique developed in this study will allow to refine the study of wild paralarvae along its development, as well as to compare wild and cultured paralarvae of similar age. Statement of relevance Artemia does not fulfil paralarval fatty acid requirements. ; This study was funded by Spanish Government under Projects OCTOPHYS (Ref. AGL2010-22120-C03), OCTOWELF (Ref. AGL2013-49101-C2-1-R) and LARECO (CTM2011-25929). Most of the authors of this paper participate to the COST network, Action FA1301 (CephsInAction) focussing on Cephalopod welfare. D. Garrido was financed by a Ph.D. grant by Spanish Institute of Oceanography (BOE 3rd November 2011). ; Peer Reviewed

13 pages, 3 tables, 8 figures ; The common octopus Octopus vulgaris is a highly valuable species worldwide, but to understand its population dynamics and requirements under culture conditions, it is crucial to improve our knowledge about its planktonic stages. Previous studies validating daily beak growth increments in these stages allowed age estimation and comparison of wild and cultured paralarvae. We aimed to improve age estimations in captivity, addressing the effect of temperature and diet, to obtain an accurate estimation of age in wild specimens collected from the coast to the open ocean off NW Spain and Morocco. We analysed the beak growth increments of reared paralarvae at 14 and 21°C with 2 different crustacean prey taxa (Artemia and spider crab Maja brachydactyla zoeae) over 30 d. Daily increment deposition at 21°C was confirmed, whereas <1 increment d−1 was recorded at 14°C. The width of the reading area grew accordingly with age; therefore, this beak region may be suitable for age estimation. A general linear model (GLM) analysis showed that temperature and the interaction of age × temperature significantly influenced increment deposition, whereas diet did not. The number of growth rings recorded in wild paralarvae beaks ranged from 0−8 on the coast, 7−11 on the continental shelf and 2−28 in the open ocean. Corrected age estimates of wild paralarvae were obtained with the GLM using the mean temperatures recorded in the wild, supporting the hypothesis that O. vulgaris leave the coastal area and develop in the open ocean transported by upwelling filaments. ; This study was funded by Spanish Government under Projects OCTOWELF (Ref. AGL2013- 49101-C2) and CAIBEX (CTM2007-66408-C02). ; Peer reviewed