Octopus Vulgaris Research Articles

Variation in Catch Size and Changes in Reproductive Biology of Common Octopus Octopus vulgaris in the Coastal Waters Off Gyeongnam, Korea

Variation in Catch Size and Changes in Reproductive Biology of Common Octopus Octopus vulgaris in the Coastal Waters Off Gyeongnam, Korea

Proteomic identification and physicochemical characterisation of paramyosin and collagen from octopus (Octopus vulgaris) and jumbo squid (Dosidicus gigas)

SummaryTo perform improvements in food science, it is fundamental to understand the physicochemical properties of proteins since their interaction with other macromolecules plays an essential role in food systems. Collagen and paramyosin help in the maintenance of the matrix structure cells, the textural behaviour and the technical functionality of the protein concentrates; because of this, their identification and characterisation are necessary. Cephalopods species have shown differences in the distribution of its muscle fibres. The amino acid profile of jumbo squid showed a high content of glycine and hydroxyproline, while octopus showed a high content of acidic amino acids. The thermal profile of jumbo squid showed an endothermic transition at 117 °C, which octopus did not present. Moreover, the proteomic identification confirms the identity of paramyosin with 33% coverage to paramyosin from Dosidicus gigas and a 4% coverage to collagen type II from Sepia pharaonis on octopus and jumbo squid, respectively.

Flocculation of Artemia induced by East Asian common Octopus octopus sinensis paralarvae under culture conditions

Artemia are potential food organisms for the mass culture of common octopus paralarvae but cause poor paralarval growth and mortality. To understand problems arising from Artemia use, we focused on Artemia flocculation in paralarval culture tanks; Artemia get caught up with each other, exhibit disrupted swimming, are deposited on the tank bottom and eventually die. To clarify whether paralarvae induce the flocculation of food organisms or not, we cultured newly hatched Artemia nauplii, 3-day-old metanauplii and decapod crustacean zoeae with or without paralarvae at different growth stages (weight). Flocculation occurred only when Artemia were cultured with paralarvae; metanauplii had a higher susceptibility for flocculation than nauplii. Flocculated Artemia proportion increased with increasing paralarval weight. Scanning electron microscopy revealed that flocculated metanauplii had deformed setules on their setae, with hook-shaped tips and adhesion of neighbouring tips, suggesting that flocculation may occur via a mechanism similar to the ‘hook-and-loop fastener’. As octopus paralarvae exhibit external digestion, digestive enzymes secreted by paralarvae may deform Artemia setules and result in flocculation. As flocculation did not occur when metanauplii were cultured in water in which paralarvae were cultured and then removed, causative enzymes were probably rapidly inactivated after secretion.

Egg survival and morphometric development of a merobenthic octopus, Octopus tetricus, embryos in an artificial octopus egg rearing system

The major limiting factor for the development of commercial scale octopus aquaculture globally is the lack of hatchery technology for incubating, hatching and raising octopus larvae to provide the seed for growout. In the absence of a hatchery seed supply, octopus aquaculture currently relies on fattening wild-caught sub-adults to market size which is commercially unsustainable. This study examines the effectiveness of an artificial octopus egg incubation system which eliminates the costs associated with maintaining females for egg brooding. The development timetable and hatching of eggs from three broods of the common Sydney octopus, Octopus tetricus, was examined in an upwelling incubation system using four experimental combinations of seawater flow and aeration. Hatching success of over 90 % was achieved in upwelling incubation systems with added aeration for all three broods, compared to 10–40% in upwelling systems without aeration. In contrast, the higher rate of seawater flow only improved hatching success in the absence of aeration, suggesting that continuous turbulence is required around developing eggs for maintaining egg health and development, especially through the reduction of infection with pathogens. The results demonstrate that incubation of O. tetricus eggs is achievable in the absence of maternal care, an important first step toward greater efficiency in hatchery production of octopus seed to supply commercial aquaculture.

A practical staging atlas to study embryonic development of Octopus vulgaris under controlled laboratory conditions

BackgroundOctopus vulgaris has been an iconic cephalopod species for neurobiology research as well as for cephalopod aquaculture. It is one of the most intelligent and well-studied invertebrates, possessing both long- and short-term memory and the striking ability to perform complex cognitive tasks. Nevertheless, how the common octopus developed these uncommon features remains enigmatic. O. vulgaris females spawn thousands of small eggs and remain with their clutch during their entire development, cleaning, venting and protecting the eggs. In fact, eggs incubated without females usually do not develop normally, mainly due to biological contamination (fungi, bacteria, etc.). This high level of parental care might have hampered laboratory research on the embryonic development of this intriguing cephalopod.ResultsHere, we present a completely parameter-controlled artificial seawater standalone egg incubation system that replaces maternal care and allows successful embryonic development of a small-egged octopus species until hatching in a laboratory environment. We also provide a practical and detailed staging atlas based on bright-field and light sheet fluorescence microscopy imaging for precise monitoring of embryonic development. The atlas has a comparative section to benchmark stages to the different scales published by Naef (1928), Arnold (1965) and Boletzky (2016). Finally, we provide methods to monitor health and wellbeing of embryos during organogenesis.ConclusionBesides introducing the study of O. vulgaris embryonic development to a wider community, this work can be a high-quality reference for comparative evolutionary developmental biology.

Regulation of growth-related genes by nutrition in paralarvae of the common octopus (Octopus vulgaris)

The common octopus (Octopus vulgaris) is a species of great interest to the aquaculture industry. However, the high mortalities registered during different phases of the octopus lifecycle, particularly the paralarvae stage, present a challenge for commercial aquaculture. Improvement of diet formulation is seen as one way to reduce mortality and improve growth. Molecular growth-markers could help to improve rearing protocols and increase survival and growth performance; therefore, over a hundred orthologous genes related to protein balance and muscle growth in vertebrates were identified for the common octopus and their suitability as molecular markers for growth in octopus paralarvae explored. We successfully amplified 14 of those genes and studied their transcription in paralarvae either fed with artemia, artemia + zoea diets or submitted to a short fasting-refeeding procedure. Paralarvae fed with artemia + zoea had higher growth rates compared to those fed only with artemia, as well as a significant increase in octopus mtor (mtor-L) and hsp90 (hsp90-L) transcription, with both genes also up-regulated during refeeding. Our results suggest that at least mtor-L and hsp90-L are likely linked to somatic growth in octopus paralarvae. Conversely, ckip1-L, crk-L, src-L and srf-L had expression patterns that did not match to periods of growth as would be expected based on similar studies in vertebrates, indicating that further research is needed to understand their function during growth and in a muscle specific context.

Mucus characterisation in the Octopus vulgaris skin throughout its life cycle.

The development of the epidermis of octopus, Octopus vulgaris, throughout its life cycle was studied by conventional staining and histochemical techniques using lectins. The mantle, the arm and the two parts of the suckers: the infundibulum and the acetabulum were analysed independently. With the exception of the suckers, the general morphology of the epidermis does not vary from the first days post-hatching to adulthood. In general terms, histochemical techniques do not indicate changes in the composition of glycoconjugates of the epidermis main cells, epithelial and secretory cells. The epithelial cells of the mantle and arm show positivity for mannose (ConA+) in their apical portions, indicating the presence of n-glycoproteins that, among other things, provide lubrication to the surface of the body. In the suckers, the apical surface of the infundibulum contains sulphated glycosaminoglycans of the N-acetylglucosamine type that provide adhesive properties. In addition to observing three types of mucocytes, m1 and m2 are characteristic of the mantle and arm, and m3 is found in the suckers. The paralarva epidermis is characterised by the presence of Kölliker's organs whose exact function is unknown. In this study, the absence of staining with alcian blue/periodic acid-Schiff(AB/PAS) prevents the possibility of attributing a secretory function. Nevertheless, the linkage of three lectins (WGA, LEL and GSL-I) in the fascicle of the organ suggests the presence of proteoglycans rich in N-acetylglucosamine that would mainly have a structural role.

Phylogeography of the insular populations of common octopus, Octopus vulgaris Cuvier, 1797, in the Atlantic Macaronesia.

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.

Sensorial Hierarchy in Octopus vulgaris's Food Choice: Chemical vs. Visual.

Simple SummaryColeoids are cephalopods endowed with a highly sophisticated nervous system with keen sense organs and an exceptionally large brain that includes more than 30 differentiated lobes. Within this group, Octopus vulgaris, well known as an intelligent soft-bodied animal, has a significant number of lobes in the nervous system dedicated to decoding and integrating visual, tactile, and chemosensory perceptions. In this study, we aimed to understand the key role of chemical and visual cues during food selection in O. vulgaris. We first defined the preferred food, and subsequently, we set up five different problem-solving tasks, in which the animal’s choice is guided by visual and chemosensory signals, either alone or together, to evaluate whether individual O. vulgaris uses a sensorial hierarchy. Our behavioural experiments show that this species does integrate different sensory information from chemical and visual cues during food selection; however, our results indicate that chemical perception provides accurate and faster information leading to food choice. This research opens new perspectives on O. vulgaris’ predation strategies.Octopus vulgaris possesses highly sophisticated sense organs, processed by the nervous system to generate appropriate behaviours such as finding food, avoiding predators, identifying conspecifics, and locating suitable habitat. Octopus uses multiple sensory modalities during the searching and selection of food, in particular, the chemosensory and visual cues. Here, we examined food choice in O. vulgaris in two ways: (1) We tested octopus’s food preference among three different kinds of food, and established anchovy as the preferred choice (66.67%, Friedman test p < 0.05); (2) We exposed octopus to a set of five behavioural experiments in order to establish the sensorial hierarchy in food choice, and to evaluate the performance based on the visual and chemical cues, alone or together. Our data show that O. vulgaris integrates sensory information from chemical and visual cues during food choice. Nevertheless, food choice resulted in being more dependent on chemical cues than visual ones (88.9%, Friedman test p < 0.05), with a consistent decrease of the time spent identifying the preferred food. These results define the role played by the senses with a sensorial hierarchy in food choice, opening new perspectives on the O. vulgaris’ predation strategies in the wild, which until today were considered to rely mainly on visual cues.

Effect of the processing of four marine species on their in vitro digestibility of Octopus vulgaris adults

The determination of in vitro digestibility of acid proteases in the digestive gland (DG) of adult O. vulgaris (> 1.2 kg) was performed, using the flesh of four different prey species (mackerel, Scomber scombrus; green crab, Carcinus maenas; swimming crab, Necora puber; Shortfin squid, Illex coindetii). For each, four processing treatments were applied: (1) frozen, (2) boiled at 100 °C for 1 min, (3) lyophilized, and (4) oven dried at 70 °C. A pH-Stat method was used to determine in vitro digestibility at pH 3. Results showed that digestibility was higher for lyophilized and frozen flesh, compared to the other treatments involving heating (boiled and oven dried), regardless of the species tested. Also, differences were found between species, within each treatment, with higher digestibility for crab (N. puber) and squid (I. coindetii). Regarding “in vitro” acid proteases digestibility, which is the most important for O. vulgaris, results indicate that heat treatments close and/or higher than 70 °C promoted changes in the flesh that prevented or reduced their assimilation by the DG of O. vulgaris.

Vertical Fibrous Morphology and Structure-Function Relationship in Natural and Biomimetic Suction-Based Adhesion Discs

Summary Recent years have seen rapid development in bio-inspired materials for adhesion. However, it remains challenging to realize robust adhesion on rough aquatic surfaces. An inspiring natural model is the remora fish, which has evolved to retain powerful adhesion to hosts using a dorsal suction disc. We find that the remora suction disc has a unique fibrous architecture of vertically oriented collagen fibers that enable anisotropic mechanical properties and enhanced adhesion performance. In the engineered prototype, vertically oriented nylon fibers are embedded into the soft silicone matrix using electrostatic flocking. The anisotropic mechanical properties are validated in both natural and biomimetic suction discs. Furthermore, the biomimetic suction disc demonstrates an enhanced adhesion function with a maximum 62.5% increase in pull-off force and a 340% increase in attachment time compared with the silicone control. This work can shed light on natural adhesion mechanisms and inspire novel designs for aquatic soft adhesives and actuators.

A standardized battery of tests to measure Octopus vulgaris' behavioural performance.

Here we introduce a series of behavioural tasks to assess inter-individual variability in behaviours exhibited by the cephalopod mollusc Octopus vulgaris. We propose that, by using octopus' predatory behavioural response, it is possible to measure: (1) the ability to adapt to the captive condition (acclimatization), (2) the response towards novel stimuli (neophobia), (3) the capability of social learning, (4) the ability of solving problems (problem solving), and (5) the response to artificial stimuli (preferences, individual learning). To assure comparability and reproducibility of results, this battery of tests is here applied to a large sample of individuals in standardized experimental conditions. Such battery of tests serves as an in vivo screening that should be adopted not only to investigate cognitive abilities in specific behavioural domains, but also to monitor the welfare status of animals under captivity, thus to check sensory functions as well as motor abilities in other investigations within the fields of biology and neuroscience. Our aim was to provide a reliable tool to exploit this animal species for research in different fields.

Feeding intensity and molecular prey identification of the common long-armed octopus, Octopus minor (Mollusca: Octopodidae) in the wild.

The common long-armed octopus, Octopus minor, is an important component of systems and supports the local fisheries in the coastal areas of northern China. For the fishery management and artificial breeding, especially for the management of exclusive conservation reserves, its role in the ecosystem requires assessment. Therefore, the feeding intensity of O. minor was studied from April to July 2014 when females reaching ovary maturation, and prey composition was identified from stomach contents using a DNA barcoding method. Of the 172 sampled octopuses, 66 had stomach contents that were nearly digested into pulp. On the whole, the feeding intensity of octopus remained more or less the same during the first three months and significantly decreased in July. The changes of feeding intensity were different between females and males; in females, the intensity of feeding decreased from April to July; in case of males, however, the feeding activity increased from April to June and decreased thereafter. The feeding intensity of the females was extremely greater than that of the males. O. minor was a generalist predator and based on homology searches and phylogenetic analysis, a total of 10 different taxa were identified in the stomach contents. In terms of percent composition by frequency of occurrences (%N), fishes accounted for the most of the octopuses diet (50%), followed by cephalopod (25%), crustaceans (21.7%), annelid (1.7%) and nematode (1.7%). The families of Gobiidae and Octopodidae appeared in all months and Protunidae appeared in three months. The results confirmed that Gobiidae family (45.8%, by frequency of occurrences) was an important source of food during the time when females reaching ovarian maturation. From April to July, the observed cannibalism showed an increasing trend. Controlling and reducing fishing production of Gobiidae fishes in conservation area are recommended from April to June when female octopuses are actively feeding.

The Eye of the Common Octopus (Octopus vulgaris).

Octopus vulgaris, well-known from temperate waters of the Mediterranean Sea and a well-cited model species among the cephalopods, has large eyes with which it scans its environment actively and which allow the organism to discriminate objects easily. On cursory examination, the single-chambered eyes of octopus with their spherical lenses resemble vertebrate eyes. However there are also apparent differences. For example, the retina of the octopus is everted instead of inverted, and it is equipped with primary rhabdomeric photoreceptors rather than secondary ciliary variety found in the retina of the vertebrate eye. The eyes of octopus are well adapted to the habitat and lifestyle of the species; the pupil closes quickly as a response to sudden light stimuli mimicking a situation in which the octopus leaves its den in shallow water during daytime. Although the many general anatomical and physiological features of octopus vision have been described elsewhere, our review reveals that a lot of information is still missing. Investigations that remain to be undertaken include a detailed examination of the dioptric apparatus or the visual functions such as brightness discrimination as well as a conclusive test for a faculty analogous to, or in lieu of, color vision. For a better understanding of the octopus eye and the functions mediated by it, we suggest that future studies focus on knowledge gaps that we outline in the present review.

Octopus Vulgaris Uses Proprioceptive and Tactile Information to Direct The&amp;nbsp; Movement of Its Arms

The octopus is an active predator with a highly flexible body and a rich behavioral repertoire. It d isplays advanced cognitive abilities, and the size of its large nervous system rivals that of many mammals. However, only one third of the neurons comprise the CNS, while the rest are located in an elaborate PNS, including eight arms, each of which contain s myriad sensory receptors of various modalities. This organization led early workers to question the extent to which the CNS is privy to non - visual sensoryinput from the periphery, and to suggests that the octopus brain has little or no capacity to finely control arm movement. We recently demonstrated that octopuses use visual information to control goal - directed complex movements of single arms. However, that study did not establish whether animals use information from the arm itself. We here report on de velopment of two - choice, single arm mazes which test the ability of an octopus to perform operant learning tasks that mimic normal octopus tactile exploration behavior, and that require the CNS to use pertinent sensory information from single arms. We show that the brain of the octopus uses peripheral information about arm motion as well as tactile input to accomplish learning tasks that entail directed control of movement. We conclude that although the arms of this cephalopod have a great capacity to act i ndependently, they also are subject to considerable central control, allowing for well organized, purposeful behavior of the organism as a whole.

Digestive enzymes and timing of digestion in Octopus vulgaris type II

The study of digestive physiology is a crucial aspect enabling commercial aquaculture of Octopus vulgaris type II. Knowing the processes of digestion, absorption, and assimilation of nutrients and factors that modulate the digestive environment is fundamental for designing adequate diets based on the digestive capacity of the animals. In the present study, we characterized the activity of total proteases in the gastric juice and digestive gland in adult O. vulgaris type II both fasted and during the postprandial period, and evaluated their digestive dynamics. In vitro experiments showed this species had predominantly acidic digestion, with maximal proteolytic activity at pH 3–4 and temperatures of 50 °C and 70 °C. These results confirmed the carnivorous feeding habit and high adaptive capacity of digestive enzymes in this species. The digestion time was 400 min at 20 °C when the digestive tract was ready to receive its next meal. Digestion occurred in two stages: the first, at the beginning of digestion, with rapid passage of soluble nutrients along the digestive tract; the second, which was slower, and involved the digestion, absorption, and assimilation of more complex nutrients (proteins and lipids). The ingestion peak occurred at 200 min after feeding when proteolytic activity was maximal. This species uses proteins as its primary source of energy and mobilizes proteins before lipids during intracellular digestion, which is a different digestion pattern to other tropical and subtropical-temperate octopus species. This new information contributes to a better understanding of the digestive physiology of O. vulgaris type II and is essential for formulating specific commercial diets for its farming.

Anthropo-niche characterization of Mediterranean cephalopods with trace elements and isotopic niches.

Human pressure leaves a mark on coastal ecosystems that can be used to study the ecology of marine species. This study compared the trace elements (TEs) composition and isotopic niche metrics of the squid Loligo vulgaris, the cuttlefish Sepia officinalis and the octopus Octopus vulgaris in the western Mediterranean Sea. The results revealed that anthropogenic pressure clearly affected coastal waters and the habitat use of these three cephalopods. Anthropogenic pressure in coastal areas, measured by the LUSI index, correlated with the TEs composition of cephalopods. The DistLM analysis showed that Cr and Zn were strong predictor variables of the LUSI matrix on all three cephalopod species. In this study, isotopic niche, combined with the CAP analysis of TEs, were plotted in a bivariate manner, which could refer to an "anthropo-niche". We provide a useful heuristic scheme for analyzing the interplay among coastal influence, trophic level, and the TEs from environment.

Ahtapot (Octopus vulgaris Cuvier, 1797)’un tanklarda bireysel yetiştiriciliği: İlk sonuçlar

The effects of individual rearing technique on the growth and survival of Octopus vulgaris (Cuvier, 1797) were investigated. Therefore, wild octopuses were reared in the transparent, perforated and caped polyethylene terephthalate (PET) pots (10 l). The assay was established as one free group rearing as a control (12.7 kg/m3 of stoking density) and two individual rearing groups as I1 and I2 (13.8 kg/m3 and 18.3 kg/m3 of stoking density, respectively). The individuals were fed mainly fresh or thawed fish at 5% body weight per day. The experiments lasted for 120 days. The acclimatization period of the octopuses lasted within 3-5 days in the individual rearing and 7-10 days in the free group rearing. The final survival rates were 100% for the control and I1 or 85.7% for I2 (P&gt;0.05). Statistically, differences were not found among the growth or specific growth rates (between 0.5 and 0.6%/day for the trials) (P&gt;0.05). The maximum density (30.7 kg/m3) was obtained from the I2 trial.

Presence of pharmaceutical compounds, levels of biochemical biomarkers in seafood tissues and risk assessment for human health: Results from a case study in North-Western Spain.

This study assessed the presence of 27 pharmaceutically active compounds belonging to common therapeutic groups (cardiovascular, antiashmatic, psychoactive, diuretic, analgesic/anti-inflammatory, and antibiotic drugs) in the tissues of representative seafood species of bivalves, cephalopods, arthropods, and fish of high economic importance and consumption rates in North-Western Spain. Four pharmaceutical compounds, out of the 27 analyzed, were detected in the collected samples. The benzodiazepine citalopram was detected in the tissues of common octopus (14.1 ng g-1 dry weight) and pod razor (9.4 ng g-1 dw). The anxiolytic venlafaxine was detected in the tissues of common cockle (2.9 ng g-1 dw). The veterinary antiparasitic ronidazole was found in pod razor (2.3 ng g-1 dw) and, finally, the psychoactive compound alprazolam was also measured in common octopus (0.3 ng g-1 dw). Hazard quotients were calculated to assess the hazard posed by the consumption of the sampled seafoods. Octopus and pod razor tissues containing citalopram and alprazolam exceeded our chosen hazard limits (HQ > 0.1) for toddlers who are high consumers of seafood (HQ values between 0.18 and 0.27). A battery of biochemical biomarkers of effects (acetylcholinesterase, glutathione S-transferase; catalase, glutathione peroxidase and glutathione reductase enzymes activities and reduced/oxidized glutathione and malondialdehyde levels) was applied to samples of the study species with the aim of characterizing their basal levels and evaluating their suitability as a tool in the monitoring chronic exposure to environmental contaminants such as those analyzed in this study. According to the measured biomarkers, pod razor and cockles have the potential to be good bioindicator species, based on the observed among-site differences detected on acetylcholinesterase, glutathione S-transferase, catalase, glutathione peroxidase activities; reduced/oxidized glutathione and malondialdehyde levels.

Synapsins are expressed at neuronal and non-neuronal locations in Octopus vulgaris

Synapsins are a family of phosphoproteins fundamental to the regulation of neurotransmitter release. They are typically neuron-specific, although recent evidence pointed to their expression in non-neuronal cells where they play a role in exocytosis and vesicle trafficking. In this work, we characterized synapsin transcripts in the invertebrate mollusk Octopus vulgaris and present evidence of their expression not only in the brain but also in male and female reproductive organs. We identified three synapsin isoforms phylogenetically correlated to that of other invertebrates and with a modular structure characteristic of mammalian synapsins with a central, highly conserved C domain, important for the protein functions, and less conserved A, B and E domains. Our molecular modeling analysis further provided a solid background for predicting synapsin functional binding to ATP, actin filaments and secretory vesicles. Interestingly, we found that synapsin expression in ovary and testis increased during sexual maturation in cells with a known secretory role, potentially matching the occurrence of a secretion process. This might indicate that its secretory role has evolved across animals according to cell activity in spite of cell identity. We believe that this study may yield insights into the convergent evolution of ubiquitously expressed proteins between vertebrates and invertebrates.