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Exploited, understudied populations of the common octopus, Octopus vulgaris Cuvier, 1797, occur in the northeastern Atlantic (NEA) throughout Macaronesia, comprising the Azores, Madeira and Canaries, and also the Cabo Verde archipelago. This octopus species, found from the intertidal to shallow continental-shelf waters, is largely sedentary, and the subject of intense, frequently unregulated fishing effort. We infer connectivity among insular populations of this octopus. Mitochondrial control region and COX1 sequence datasets reveal two highly divergent haplogroups (α and β) at similar frequencies, with opposing clinal distributions along the sampled latitudinal range. Haplogroups have different demographic and phylogeographic patterns, with origins related to the two last glacial maxima. FST values suggest a significant differentiation for most pairwise comparisons, including insular and continental samples, from the Galicia and Morocco coasts, with the exception of pairwise comparisons for samples from Madeira and the Canaries populations. Results indicate the existence of genetically differentiated octopus populations throughout the NEA. This emphasizes the importance of regulations by autonomous regional governments of the Azores, Madeira and the Canaries, for appropriate management of insular octopus stocks. [ABSTRACT FROM AUTHOR]

Underwater volcanic eruptions are a type of natural contamination that affect all marine organisms at a local level. These eruptions usually begin and end a degassing stage of the volcano that, although they do not affect the magnitude of magma emanation, affect organisms to a lesser degree locally, such as cephalopods that due to their metabolism and trophic level, are good bioindicators of contamination. A total of 180 samples of three species of cephalopods were collected for the study: sixty Sepia officinalis , sixty Octopus vulgaris and sixty Loligo vulgaris in the area of the submarine volcano in El Hierro, Tenerife and Lanzarote in the Canary Islands (twenty samples per species in each location), and the metal concentrations (Al, Cd, Cr, Cu, Fe, Li, Ni, Pb and Zn) in each of the samples were analyzed. All species showed significant differences for all metals in El Hierro compared to Tenerife and Lanzarote. All the analyzed species from El Hierro had higher concentrations of the nine studied metals, this is due to the fact that they were caught near the Tagoro submarine volcano, which at the time was in a state of degassing and discharged many metal-rich compounds. [Display omitted] • All the analyzed species from El Hierro showed higher concentrations of the nine metals studied. • The submarine volcano has a great influence on the high metal content of the species. • All species showed significant differences for all metals in all zones. • Sepia officinalis and Octopus vulgaris had higher concentrations of most of the metals. [ABSTRACT FROM AUTHOR]

Cabranes, C., Fernandez-Rueda, P., and Martínez, J. L. 2008. Genetic structure of Octopus vulgaris around the Iberian Peninsula and Canary Islands as indicated by microsatellite DNA variation. – ICES Journal of Marine Science, 65: 12–16.Microsatellite DNA markers were used for a genetic study of Octopus vulgaris, a cephalopod species of great commercial interest to Spain and Portugal, and therefore subjected to intensive fishing. Improving the demographic knowledge of marine resources supports more-responsible management and conservation. Genetic variation at five microsatellite loci screened in six samples from NE Atlantic and Mediterranean coasts of the Iberian Peninsula was high [mean number of alleles = 18.3, mean He = 0.874]. Analysis of the microsatellites allowed significant subpopulation structure to be identified, consistent with an isolation-by-distance model for Atlantic populations. Differences between pairs of samples separated by <200 km were not significant. From a fisheries management perspective, the results support coordinated management of neighbouring stocks of O. vulgaris around the Iberian Peninsula. [ABSTRACT FROM PUBLISHER]

The common octopus, Octopus vulgaris Cuvier, 1797 is the most important cephalopod species in catches of the artisanal trap fishery in Canary Islands waters. Based on monthly samplings carried out off Gran Canaria (Canary Islands), 760 specimens of the common octopus, ranging from 4.8 to 165 mm ventral mantle length, were studied from June 1996 to July 1997, and from December 1997 to June 1999. The length–weight relationships found were W=0.0007×VML3.096 (n=760; r=0.95), W=0.0007×VML3.112 (n=481; r=0.86), W=0.0007×VML3.098 (n=247; r=0.77), for all the specimens caught, males and females, respectively.The proportion of males was significantly higher than females. Males predominated in all size intervals. Males and females become sexually mature at 105 and 113 mm of VML, respectively. Maturation and spawning occur all year around, with more intensity from January to July, with a peak in April. There is a second spawning period in October–November.The number of spermatophores produced increased with length and maturity stage. The production of spermatophores by individual body weight fluctuated from 0.29 to 0.03 spermatophores/g. The number of oocytes per gram of body weight fluctuated from 108 to 465. The real fecundity oscillated between 31 and 106 eggs spawned per gram of female body weight. [Copyright &y& Elsevier]