Wild Octopus Research Articles

The best defense is a good offense: Anti-predator behavior of the common octopus (Octopus vulgaris) against conger eel attacks.

We present the description of defensive behavior in wild Octopus vulgaris against conger eel (Conger conger) attacks based on three video sequences recorded by recreational SCUBA divers in the eastern Atlantic off the coast of Galicia (NW Spain) and in the Cantabrian Sea (NW Spain). These records document common traits in defensive behavior: (1) the octopuses enveloped the conger eel's head to obscure its view; (2) they covered the eel's gills in an attempt to suffocate it; (3) they released ink; (4) the octopuses lost some appendages because of the fight. In the third video, the octopus did not exhibit the defensive behavior described in the first two videos due to an inability to utilize its arms in defense, and the conger eel's success in capturing octopuses is discussed. Additionally, both the cost that the octopus could face by losing some arms during the fight and whether the experience it acquires can be an advantage for future encounters are analyzed. The defensive behavior exhibited by octopuses in this study highlights their ability to survive in a hostile environment and serves as an example of the extensive repertoire of anti-predator strategies employed by these cephalopods.

Assessing Negative Welfare Measures for Wild Invertebrates: The Case for Octopuses.

Welfare metrics have been established for octopuses in the laboratory, but not for octopuses living in the wild. Wild octopuses are constantly exposed to potentially harmful situations, and the ability to assess the welfare status of wild octopuses could provide pertinent information about individuals' health and species' resilience to stressors. Here, we used underwater photos and videos to identify injuries and stress-related behaviors in wild Octopus insularis in a variety of contexts, including interacting with fishermen, interacting with other octopuses and fish, proximity to predators, in den, foraging, and in senescence. We adapted established metrics of octopus welfare from the laboratory to these wild octopuses. In addition to observing all of the stress measures, we also identified two previously unknown measures associated with decreased welfare: (1) a half white eye flash and (2) a half-and-half blotch body pattern. More than half of the individuals analyzed had arm loss, and almost half of the individuals had skin injuries. We also observed that irregular chromatophore expression and abnormal motor coordination were associated with interactions with fishermen. This is the first study to apply measures of welfare from the laboratory to wild octopuses. Our results may also aid in the identification of welfare measures for other wild invertebrates.

Trophic ecology of Octopus vulgaris paralarvae along the Iberian Canary current eastern boundary upwelling system

Our knowledge of the diet of wild octopus paralarvae, Octopus vulgaris, is restricted to the first 2 weeks of its planktonic phase when they are selective hunters found near the coastline. These small paralarvae, bearing only three suckers per arm, are transported by oceanic currents from the coast towards offshore waters, where they complete the planktonic phase over 2 months. Here, we have investigated the trophic ecology of O. vulgaris paralarvae in two contrasting upwelling sub-regions of the Iberian Canary current (ICC) eastern boundary upwelling system and have evaluated dietary change as paralarvae develop (inferred by counting the number of suckers per arm, ranging from three to 15) along the coastal-oceanic gradient during their planktonic phase. Using high-throughput amplicon sequencing, we have characterised the diet of 100 paralarvae collected along the Northwest Iberian Peninsula (n = 65, three to five suckers per arm) and off the west coast of Morocco (n = 35, three to 15 suckers per arm), identifying up to 87 different prey species. The diet of paralarvae varied along the ICC, with crabs (53.4%), siphonophores (12.2%), copepods (12.3%), cnidarians (8.4%) and pteropods (3.7%) accounting for 90% of the variability detected off NW Iberian Peninsula, whereas off W Morocco, crabs (46.2%), copepods (23.1%), cnidarians (12.9%), krill (9.3%) and fishes (4.2%) explained 95.6% of the variability observed using frequency of observance (FOO%) data. Ontogenetic changes in the diet based on groups of paralarvae with similar numbers per arm were evidenced by the decreasing contribution of coastal meroplankton and an increase in oceanic holoplankton, including siphonophores, copepods, pteropods and krill. Trophic niche breadth values ranged from 0.06 to 0.67, with averaged values ranging from 0.23 to 0.33 (generalist = 1 and specialist = 0), suggesting that O. vulgaris paralarvae are selective predators through their ontogenetic transition between coastal and oceanic environments.

In the line of fire: Debris throwing by wild octopuses.

Wild Octopus tetricus frequently propel shells, silt, and algae through the water by releasing these materials from their arms while creating a forceful jet from the siphon held under the arm web. These "throws" occur in several contexts at a site in Jervis Bay, Australia, including in interactions with other octopuses. Material thrown in interactive contexts frequently hits other octopuses. Some throws appear to be targeted on other individuals, as suggested by several kinds of evidence: Throws in interactive contexts were more vigorous than others, and more often used silt, rather than shells or algae. High vigor throws were more often accompanied by uniform or dark body patterns than other throws. Some throws were directed differently from beneath the arms and such throws were more likely to hit other octopuses. Throwing at other individuals in the same population, as apparently seen in these octopuses, is a rare form of nonhuman projectile use, previously seen only in some social mammals.

You Are What You Eat: A Genomic Analysis of the Gut Microbiome of Captive and Wild Octopus vulgaris Paralarvae and Their Zooplankton Prey.

The common octopus (Octopus vulgaris) is an attractive species for aquaculture, however, several challenges inhibit sustainable commercial production. Little is known about the early paralarval stages in the wild, including diet and intestinal microbiota, which likely play a significant role in development and vitality of this important life stage. High throughput sequencing was used to characterize the gastrointestinal microbiome of wild O. vulgaris paralarvae collected from two different upwelling regions off the coast of North West Spain (n = 41) and Morocco (n = 35). These were compared to that of paralarvae reared with Artemia for up to 25 days in captivity (n = 29). In addition, the gastrointestinal microbiome of zooplankton prey (crabs, copepod and krill) was also analyzed to determine if the microbial communities present in wild paralarvae are derived from their diet. Paralarvae reared in captivity with Artemia showed a depletion of bacterial diversity, particularly after day 5, when almost half the bacterial species present on day 0 were lost and two bacterial families (Mycoplasmataceae and Vibrionaceae) dominated the microbial community. In contrast, bacterial diversity increased in wild paralarvae as they developed in the oceanic realm of both upwelling systems, likely due to the exposure of new bacterial communities via ingestion of a wide diversity of prey. Remarkably, the bacterial diversity of recently hatched paralarvae in captivity was similar to that of wild paralarvae and zooplankton, thus suggesting a marked effect of the diet in both the microbial community species diversity and evenness. This study provides a comprehensive overview of the bacterial communities inhabiting the gastrointestinal tract of O. vulgaris paralarvae, and reveals new research lines to challenge the current bottlenecks preventing sustainable octopus aquaculture.

Size-assortative mating and arm loss in the wild shallow-water octopus Abdopus sp. (Cephalopoda: Octopodidae)

ABSTRACTThe ability to autotomise and regenerate body parts as a means of escaping predation or renewing damaged tissues has evolved in several animal groups. Some octopuses belonging to the genus Abdopus are known for a high frequency of arm loss and their capacity to regenerate arms. I investigated the mating behaviour and the incidence of arm loss in a shallow-water Abdopus sp. in the wild. Mating occurred at night and at low tide. The male octopus tracked and copulated by repeatedly stretching the hectocotylised arm into the female’s mantle cavity during mating bouts, mostly while the mated female actively moved to forage at the same time. Relatively smaller males adopted sneaking tactics in which they stayed around a mating pair and sometimes gained opportunistic copulations with the female. A significant positive relationship between the body weights of the male and female in each mating pair was detected. Moreover, the proportion of sneaker males that had lost at least one arm prior to mating and their number of lost arms per individual were significantly higher than those of paired males. These results suggest that male arm loss in Abdopus sp. may directly or indirectly influence male competition over females and mating success, resulting in a positive size association between members of a mating pair. This finding would be important when considering the life-history strategies of octopuses.

Fatty acid composition and age estimation of wild Octopus vulgaris paralarvae

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 8days and their FA composition resembled that from hatchlings produced under culture conditions. However, when compared with the FA composition of up to 20days 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 relevanceArtemia does not fulfil paralarval fatty acid requirements.

Influence of different temperature and body weight on <I>Octopus vulgaris</I> respiratory metabolism in the South China Sea

The relationship between oxygen consumption rate, ammonia excretion rate and water temperature,body weight and the respiratory metabolism of wild Octopus vulgaris in South China Sea were investigated with a breather apparatus in closed static seawater system. The experimental results showed that water temperature had apparent effect on oxygen consumption rate and ammonia excretion rate(P0.05), while the influence of weight was not significant(P0.05). Under 16 32℃, the oxygen consumption rate and ammonia excretion rate first increased and then decreased with increasing temperature; under the same temperature, no significant changes were observed among different body weight. Temperature of 24℃ may be the kick point for Octopus vulgaris respiratory metabolism. Under this temperature, the highest oxygen consumption rate,ammonia excretion rate and fastest metabolic rate were recorded. At 24℃, Octopus vulgaris oxygen consumption rate and ammonia excretion rate were 0.86 mg/(g·h) and 36.69 μg/(g·h) per unit of body mass, respectively. The result of respiratory metabolism substrate analysis showed that under 24 28℃ the ratio of O:N increased with temperature increasing, which indicated that the proportion of energy provided by protein decreased.

Molecular prey identification in wild Octopus vulgaris paralarvae

The trophic ecology of Octopus vulgaris paralarvae collected in 2008 off the Ría de Vigo, NW Spain (42° 12.80′ N–9° 00.00′ W), was approached by both morphological and molecular methods. External digestion of prey and posterior suction of the liquefied contents by wild O. vulgaris paralarvae made the morphological identification of gut contents impossible. Thus, a PCR-based method using group-specific primers was selected to identify prey consumed by O. vulgaris paralarvae in the pelagic realm. The mitochondrial ribosomal 16S gene region was chosen for designing group-specific primers, which targeted a broad range of crustaceans and fishes but avoided the amplification of predator DNA. These primers successfully amplified DNA of prey by using a semi-nested PCR-based approach and posterior cloning. Homology search and phylogenetic analysis were then conducted with the 20 different operational taxonomic units obtained to identify the putative organisms ingested. The phylogenetic analysis clustered ingested prey into 12 families of crustaceans (11 belonging to the order Decapoda and 1 to the order Euphausiacea) and two families of fishes (Gobiidae and Carangidae). According to the Czekanowski’s Index (CI), the trophic niche breadth of O. vulgaris paralarvae is low (CI = 0.13), which means that these paralarvae are specialist predators at least during the first weeks of their life cycle. It is the first time that natural prey has been identified in O. vulgaris paralarvae collected from the wild, and such knowledge may be critical to increasing the survival of O. vulgaris hatchlings in captivity, a goal that has been actively pursued since the 1960s by aquaculture researchers.

Vitamin A and E content in early stages of cephalopods and their dietary effects in Octopus vulgaris paralarvae

The present study was designed to provide a look at the vitamin content of the early stages of cephalopods as an approach to their vitamin requirements in culture. Vitamin A and E profiles of the European cuttlefish Sepia officinalis, European squid Loligo vulgaris and common octopus Octopus vulgaris laboratory hatchlings and wild juveniles were analyzed. In addition, for O. vulgaris we determined vitamin A and E profiles of mature ovaries and eggs at different stages of development, and followed their possible dietary effects during the first month of paralarval rearing. We also analyzed vitamin A and E content of the live prey, i.e. Artemia nauplii, Maja brachydactyla hatchling crab zoeae and the mysidacean shrimp Leptomysis buergii. In the octopus ovaries and eggs, the vitamin A and E concentrations remained globally higher compared to paralarvae and wild juveniles. The vitamin A content in early stages of cephalopods was not much different from that observed in other marine molluscs and fish larvae and is expected to come from the carotenoid pool of their crustacean prey. Relatively high content of vitamin E was observed in the octopus ovaries, eggs, hatchlings and juveniles of the three cephalopod species analyzed. These levels are probably related to the high percentage of long chain polyunsaturated fatty acids (PUFA) that are particularly high in paralarval and juvenile cephalopods. The vitamin E content of the natural prey, M. brachydactyla and L. buergii, seemed to match or exceed the dietary needs of the three species of cephalopods analyzed. The vitamin E content of the Artemia-fed O. vulgaris increased during the rearing period and the content of the one month of age paralarvae did not differ from the content in wild octopus juveniles, suggesting that this prey may provide sufficient tocopherol for the young octopuses.

Determining the age and growth of wild octopus using stylet increment analysis

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 367:213-222 (2008) - DOI: https://doi.org/10.3354/meps07558 Determining the age and growth of wild octopus using stylet increment analysis Stephen C. Leporati*, Jayson M. Semmens, Gretta T. Pecl Tasmanian Aquaculture and Fisheries Institute Marine Research Laboratories, University of Tasmanian, Private Bag 49, Hobart, Tasmania 7001, Australia *Email: stephen.leporati@utas.edu.au ABSTRACT: Stylet increment analysis is a method of octopus age estimation that quantifies growth rings within stylets (reduced internal shells found in the mantle). This method was applied to wild Octopus pallidus to determine gender and seasonal influences on age and growth. A total of 503 individuals (94 males and 409 females) were aged, revealing that O. pallidus can reach a maximum age of approximately 1.6 yr and that spawning occurs throughout the year. Male octopuses on average were significantly larger (550 and 482 g for males and females, respectively) and older (259 and 243 d for males and females, respectively) than female, and overall growth rates were positively correlated with temperature at hatching. However, these differences were secondary to individual growth heterogeneity. Growth of males ranged from 1.32 to 5.33% body weight (bw) d–1 and females from 1.55 to 6.9% bw d–1, with no relationship between age and size evident regardless of sex. Stylet increment analysis is a promising technique that could play a role similar role to statoliths in squid as an ageing tool. KEY WORDS: Octopus · Stylet increment analysis · Age · Growth · Seasonal effects Full text in pdf format PreviousNextCite this article as: Leporati SC, Semmens JM, Pecl GT (2008) Determining the age and growth of wild octopus using stylet increment analysis. Mar Ecol Prog Ser 367:213-222. https://doi.org/10.3354/meps07558 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 367. Online publication date: September 11, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Reproductive status of Octopus pallidus, and its relationship to age and size

Age-specific information on individual octopus reproductive development and investment from wild populations has until recently been unobtainable. Using daily-formed increments within stylets (internal shells) the individual ages of 503 wild Octopus pallidus were determined. In addition, detailed reproductive information was collected for each of the aged octopus, along with reproductive data for an additional 925 octopus. All of the octopus were collected from Bass Strait waters in south-eastern Australia from November 2004 to November 2006. This information was used to investigate seasonal trends in reproductive scheduling and investment, fecundity and egg size. Maturation in O. pallidus primarily depends on size with little relationship to age and is highly variable between genders, with females >350 days still maturing in comparison to all males >142 days being mature. Size at 50% maturity for females was approximately 473 g, which is considerably larger than male 100% maturity at <250 g. This indicates that for females at least, maturity does not necessarily come with age. Seasonal scheduling in reproductive investment between genders revealed an optimal spawning period between late summer and early autumn. These results reinforce the view that individual growth and maturity is highly variable in cephalopods.

Observations on associated histopathology with Aggregata octopiana infection (Protista: Apicomplexa) in Octopus vulgaris.

Gamogony and sporogony of Aggregata octopiana were commonly observed during histological examination of the digestive tract of wild Octopus vulgaris from Ria de Vigo (NW Spain). A. octopiana infected noncuticularized caecum and intestine, and cuticularized oesophagus and crop. Infection was also observed in the gills and in covering mesenterium, mainly of the digestive gland and gonad. Histological and ultrastructural lesions associated with A. octopiana included host cell hypertrophy with nuclear displacement, inflammation, phagocytosis, ulceration and destruction of organ architecture. The possible existence of a malabsorption syndrome in the host is deduced.

Subcutaneous electromagnetic tagging of benthic octopus: a preliminary evaluation

Electromagnetic tags were subcutaneously implanted in the dorsal crown of 28 octopus (20 aquarium tagged; and 8 wild octopus tagged in situ) from two species: Octopus tetricus and O. maorum. Laboratory tagged octopus retained tags for the duration of the study (14 months), as did octopus tagged in the wild (13 weeks). No signs of lesions, physical deterioration, or abnormal behaviours were apparent in either laboratory or field tagged octopus. Tagging had no significant effect on growth trajectories. Both laboratory and field tagged octopus appeared healthy, physically vigorous, maintained voracious apetites, and regularly stalked and attacked vigorous prey (laboratory observations only). Subcutaneously implanted electromagnetic tags enabled individuals to be tagged, and tags to be read in situ with minimal disturbance to the animal. Electromagnetic tagging is a potentially invaluable tool in studying benthic octopus and may have similar value in the study of many cephalopods and other soft bodied organisms.

Growth lines within the beak microstructure of the octopus Octopus vulgaris Cuvier, 1797

Octopus vulgaris Cuvier, 1797 is commercially the most important species in the central-eastern Atlantic cephalopod fishery. The estimation of growth parameters in wild octopus populations is essential to management of the fishery. As there are problems with methods based on length-frequency modal analyses for describing growth from field data and there is a lack of age determination techniques for octopod species, estimation of the growth rates of natural populations is currently difficult. The present work describes the use of beaks to determine the age of O. vulgaris, using a new method based on a sample of beaks from 25 animals caught in the area in 1993. After sectioning different planes of the beaks embedded in resin blocks, they were analysed to select the best with which to observe growth increments. The sagittal plane (from outer to inner) revealed a pattern of increments of similar width in the internal rostral area of all the beaks analysed that are possibly related to the age of the animal. Th...

Octopus bimaculoides (Pickford &amp; McConnaughey, 1949): a marine invertebrate host for ectoparasitic protozoans

Abstract. During the laboratory culture of the California mud‐fiat oetopus. Octopus bimaculoides(Pickford &amp; McConnaughey, 1949), concurrent infestations of ectoparasitic flagellate and ciliate protozoans were discovered when examining sick and dying animals. The flagellates, similar to the bodonid parasite, Ichthyobodo necator (Henneguy, 1883), were small (3–9 μm total length) and infested any surface epithelia exposed to sea water. The larger ciliates (l5–30 μm total length), believed to be ancistrocomids, were found only on the gills. This is the first documented report of ciliate or flagellate ecto‐parasites infesting cephalopod molluscs. Flagellate infestations were first manifest on the dorsal arms and mantle surfaces of O. bimaculoides as white spots visible when the octopuses were in dark colouration. Lesions formed at the centres of the spots and the interspersed lesions eventually connected. Once the parasites damaged the epidermis, secondary bacterial infections caused lesioning. Both parasites heavily infested the gills. Clinical signs first appeared at 2 months post‐hatching (0‐5 g). Octopuses seemed to become refractory to the disease beyond a size of 25 g. No effective treatment was found for these infestations. It was possible to eliminate parasite spread in the laboratory by prefiltering water to l μm. The source of the parasites was the wild octopus population of the southern California coast.