How old are giant squids? First approach to aging Architeuthis beaks

The giant squid Architeuthis dux Steenstrup, 1857 is one of the largest and most enigmatic marine species. Its age estimation remains controversial with many estimates of maximum age ranging from 1 to 14 yrs. Successful results regarding the study of aging in cephalopod beaks for some octopod and oegopsid squids support using these structures for age estimation. We analyzed the beaks of 10 individuals, caught between 1995 and 2006, with reconstructed dorsal mantle lengths (DMLs) between 823 and 1418 mm. The beaks were measured and weighed, and their microstructure was analyzed in three ways: (1) in the rostrum area [rostrum sagittal sections (RSS)] for both upper and lower jaws, and the (2) inner lateral wall surfaces (LWS) and (3) inner crest surfaces (CS) for upper jaws. A constant sequence of increments was observed along the RSS, indicating that the use of lower jaws is more feasible due to the higher erosion and tighter packing of increments of upper jaws. The statolith of one individual was analyzed, resulting in 520 increments (579 increments from RSS of its lower jaw). Assuming daily deposition, the age estimations in RSS between 411 and 674 d suggest rapid growth of A. dux, averaging 1.97 mm DML d–1 (SD 0.45). When maximum ages were estimated by applying these results to the largest measured specimens in the literature (e.g., 2400 mm DML), an age of approximately 3 yrs was obtained. Analysis over a greater size range of individuals would allow more accurate age estimations of this emblematic squid.En prensa1,14

Age of spent Octopus vulgaris and stress mark analysis using beaks of wild individuals

Age estimation of the cephalopod Octopus vulgaris by using beaks has improved in recent years, but maximum age and longevity in the wild have not been confirmed due to the low availability of senescent wild octopuses. In this study, a beak analysis of lateral wall surfaces (LWS) from 20 spent specimens confirmed the one-year lifecycle of the species in Central East Atlantic waters. Stress marks (checks) were clearly located in the daily increment sequence of rostrum sagittal sections (RSS). The highest daily variations in sea surface temperature (ΔT) that occurred during the last months of their lifetimes coincided with the locations of the marks on the beak, enabling confirmation of O. vulgaris beaks as life recorders for the first time. It also supports the daily deposition of RSS beak increments in the wild. Individuals were grouped into two main zones, at 20ºN and 18ºN respectively. Both groups showed different thermal check patterns, in accordance with the oceanographic differences. Two other checks (not coinciding with high values of ΔT) were observed in RSS at averages of 15 and 28 days before death, respectively, which were interpreted as responding to senescent-related events.Instituto Espanol de Oceanografi

Fatty acids composition and age estimation of wild Octopus vulgaris paralarvae

Under culture conditions, lipid composition and specifically, the fatty acid profile of reared paralarvae is significantly different from hatchlings. Therefore, comparing wild paralarvae and reared paralarvae of similar age would allow us to elucidate if the changes in fatty acid profile are related with a non-optimal prey composition or are caused by the normal development. The aim of this study was analyze, for the very first time, the fatty acid profile of wild Octopus vulgaris paralarvae individually, determining for each paralarvae their age through deposition of daily increments on lateral hood surface of the beaks. The main goal is to clear up lipid requirements of paralarvae and optimise the diet of reared paralarvae

ESTIMACIÓN DE LA EDAD Y DETERMINACIÓN DEL PERFIL DE ÁCIDOS GRASOS EN PARALARVAS SALVAJES DE PULPO COMÚN (Octopus vulgaris)

Bajo condiciones de cultivo, la composición lipídica y, específicamente, el perfil de ácidos grasos de las paralarvas cultivadas, es significativamente diferente al de las paralarvas recién eclosionadas. Por tanto, la comparación entre paralarvas salvajes y cultivadas de edad equivalente, permitiría dilucidar si estos cambios detectados en el perfil de ácidos grasos están relacionados con una dieta inadecuada o son causados por el propio desarrollo de la paralarva. En el presente estudio, se analizó por primera vez de forma individual el perfil de ácidos grasos de paralarvas salvajes de Octopus vulgaris y se determinó su edad a través de la deposición diaria de los incrementos en los picos, con el objetivo de profundizar en los requerimientos lipídicos de las paralarvas a lo largo del desarrollo y de esta forma intentar optimizar la dieta de los ejemplares en cultivo