Metal accumulation and oxidative stress biomarkers in octopus (Octopus vulgaris) from Northwest Atlantic

Metals are ubiquitous in the environment and accumulate in aquatic organisms and are known for their ability to enhance the production of reactive oxygen species (ROS). In aquatic species, oxidative stress mechanisms have been studied by measuring antioxidant enzyme activities and oxidative damages in tissues. The aim of this study was to apply and validate a set of oxidative stress biomarkers and correlate responses with metal contents in tissues of common octopus (Octopus vulgaris). Antioxidant enzyme activity (catalase — CAT, superoxide dismutase — SOD and glutathione S-transferases — GST), oxidative damages (lipid peroxidation — LPO and protein carbonyl content — PCO) andmetal content (Cu, Zn, Pb, Cd and As) in the digestive gland and armof octopus, collected in the NWPortuguese coast in different periods, were assessed after capture and after 14 days in captivity. CAT and SOD activitieswere highly responsive to fluctuations inmetal concentrations and able to reduce oxidative damage, LPO and PCO in the digestive gland. CAT activity was also positively correlated with SOD and GST activities, which emphasizes that the three enzymes respond in a coordinated way to metal induced oxidative stress. Our results validate the use of oxidative stress biomarkers to assess metal pollution effects in this ecological and commercial relevant species.Moreover, octopus seems to have the ability to control oxidative damage by triggering an antioxidant enzyme coordinated response in the digestive gland.

Seasonal patterns of polycyclic aromatic hydrocarbons in digestive gland and arm of octopus (Octopus vulgaris) from the Northwest Atlantic

Among organic pollutants existing in coastal areas, polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their ubiquity and carcinogenic potential. The aim of this study was to evaluate the seasonal patterns of PAHs in the digestive gland and arm of the common octopus (Octopus vulgaris) from the Northwest Atlantic Portuguese coast. In the different seasons, 18 PAHs were determined and the detoxification capacity of the species was evaluated. Ethoxyresorufin O-deethylase (EROD) and ethoxycoumarin O-deethylase (ECOD) activities were measured to assess phase I biotransformation capacity. Individual PAH ratios were used for major source (pyrolytic/petrogenic) analysis. Risks for human consumption were determined by the total toxicity equivalence approach. Generally, low levels of PAHs were detected in the digestive gland and in the arm of octopus, with a predominance of low molecular over high molecular weight compounds. PAHs exhibited seasonality in the concentrations detected and in their main emission sources. In the digestive gland, the highest total PAH levels were observed in autumn possibly related to fat availability in the ecosystem and food intake. The lack of PAH elimination observed in the digestive gland after captivity could be possibly associated to a low biotransformation capacity, consistent with the negligible/undetected levels of EROD and ECOD activity in the different seasons. The emission sources of PAHs found in the digestive gland varied from a petrogenic profile observed in winter to a pyrolytic pattern in spring. In the arm, the highest PAH contents were observed in June; nevertheless, levels were always below the regulatory limits established for food consumption. The carcinogenic potential calculated for all the sampling periods in the arm were markedly lower than the ones found in various aquatic species from different marine environments. The results presented in this study give relevant baseline data for environmental monitoring of organic pollution in coastal areas.

Accumulation, responses and genotoxicity of trace elements in octopus vulgaris

Dissertação apresentada para obtenção do Grau de Doutor em Bioquímica pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Spawning habitat selection by Octopus vulgaris: new insights for a more effective management of this resource

The selection of spawning habitat of a population of Octopus vulgaris that is subject to a small-scale exploitation was studied in the Cíes Islands within the National Park of the Atlantic Islands of Galicia (NW Spain). The technique used was visual censuses by scuba diving. We conducted 93 visual censuses from April 2012 to April 2014. The total swept area was 123.69 ha. Habitat features (season, depth, zone, bottom temperature, swept area, bottom substrate type, and creels fishing impact) were evaluated as predictors of the presence/absence of spawning dens using GAM models. O. vulgaris has a noteworthy preference for spawning in areas with hard bottom substrate and moderate depth (approximately 20 m). The higher density of spawning dens (1.08ha−1) was found in a surveyed area of 50.14ha located in the northeastern part of the northern Cíes Island. We propose to protect the area comprised from Punta Escodelo to Punta Ferreiro between 5 and 30 m depth. This area has a surface of 158 ha equivalent to 5.98% of the total marine area of the Cíes islands. The strengths and weaknesses of a management strategy based on the protection of the species’ spawning habitat are discussed.

Determinación de periodos de engorde de Octopus vulgaris en el Delta del Ebro: Rango térmico óptimo

Se ha realizado un estudio sobre los efectos de la temperatura en el crecimiento de O. vulgaris en tanque en tierra, con el fin de trasladar esta información a un posible futuro cultivo de esta especie en la bahía dels Alfacs. Se incide en los efectos que las temperaturas extremas tienen sobre las tasas de ingestión relativa, el crecimiento absoluto y relativo y la supervivencia. Los resultados indican como rango óptimo de alimentación y crecimiento el comprendido entre 15-24ºC.

Efeito sazonal sobre os ácidos graxos e colesterol do polvo Octopus vulgaris Cuvier 1797

Foi realizado um estudo sobre o perfil de ácidos graxos e colesterol na manta de polvo comum, Octopus vulgaris, capturado na praia de Camocim - CE, no decorrer dos meses de abril a outubro em coletas bimensais. Apesar do ácido oleico (C18: 1n9) apresentar comportamento uniforme ao longo do tempo de coleta, a maioria dos demais ácidos graxos foi afetada (p = 1%) pela época de coleta. Os níveis dos ácidos araquidônico (C20:4n6), oleico (C18:1n9), esteárico (C18:0) e linoleico (C18:2n6) foram superiores àqueles reportados na literatura. O somatório de ácidos graxos poli-insaturados e monoinsaturados revelou que o óleo de polvo apresenta um teor significativo de ácidos graxos insaturados. Foi observado um aumento gradativo de colesterol ao longo do tempo estudado e um comportamento inverso para a relação de ácidos graxos n3/n6.

Infiltrated plaques resulting from an injury caused by the common octopus (Octopus vulgaris): a case report

Several species of octopus are considered venomous due to toxins present in the glands connected to their "beak", which may be associated with hunt and kill of prey. Herein, we report an accident involving a common octopus (Octopus vulgaris) that injured an instructor during a practical biology lesson and provoked an inflamed infiltrated plaque on the hand of the victim. The lesion was present for about three weeks and was treated with cold compresses and anti-inflammatory drugs. It was healed ten days after leaving a hyperchromic macule at the bite site. The probable cause of the severe inflammation was the digestive enzymes of the glands and not the neurotoxins of the venom.

Evidence for genetic differentiation of Octopus vulgaris (Mollusca, Cephalopoda) fishery populations from the southern coast of Brazil as revealed by microsatellites

Octopus vulgaris is a cephalopod species in several oceans and commonly caught by artisanal and industrial fisheries. In Brazil, O. vulgaris populations are mainly distributed along the southern coast and have been subjected to intensive fishing during recent years. Despite the importance of this marine resource, no genetic study has been carried out to examine genetic differences among populations along the coast of Brazil. In this study, 343 individuals collected by commercial vessels were genotyped at six microsatellite loci to investigate the genetic differences in O. vulgaris populations along the southern coast of Brazil. Genetic structure and levels of differentiation among sampling sites were estimated via a genotype assignment test and F-statistics. Our results indicate that the O. vulgaris stock consists of four genetic populations with an overall significant analogous F(ST). (phi(CT) = 0.10710, P<0.05) value. The genetic diversity was high with an observed heterozygosity of Ho = 0.987. The negative values of F(IS) found for most of the loci examined suggested a possible bottleneck process. These findings are important for further steps toward more sustainable octopus fisheries, so that this marine resource can be preserved for long-term utilization. (C) 2011 Elsevier B.V. All rights reserved.

Engorde de pulpo (Octopus vulgaris) alimentado exclusivamente con boga (Boops boops) de descarte de la acuicultura

[EN] The use of low value fish (Bogue, Boops boops), accidentally reared in seabream culture cages, as a sole food in octopus farming was tested in two different experiments located in Canary Islands. In a first experiment two different initial sizes were compared: 1,5 kg & 2,3 kg, both at a density of 11 kg/m3. Initial density was increased in a second experiments to 16 kg/m3 testing two lower initial weights: 1,0 kg & 0,8 kg. Bogue as a single feed was found to be good enough to sustain a good growth in octopus cage rearing. Best growth in terms of specific growth rate and average daily growth was obtained with the lowest grow size, 0,8 kg.

Methodology to create a proxy climate index for environmental and Octopus vulgaris fishery studies at the Northwest Africa: analytical and mathematical analyses

Diploma de Estudios Avanzados y Tesis de Máster