Search

In upwelling systems around the world, octopus abundance is forecast by marine productivity linked to upwelling strength, often indicated by sea-surface temperatures. Climate change may disrupt populations of marine animals that are linked to such temperature-dependent events. We analysed the relationship of the abundance of giant Pacific octopuses (Enteroctopus dofleini) to Gulf of Alaska and Washington State water temperatures. Abundance was measured in targeted visual surveys in Prince William Sound, Alaska, over the period 1995–2016 and from REEF.org diver surveys in Washington State from 2003 to 2019. Octopus counts from both survey programs had significant negative correlations with water temperatures over the previous 2.5–4 years. Water temperature accounted for from 0.41 to 0.71 of the variance (R2) in octopus abundance in eastern Gulf of Alaska waters located in ocean currents up-stream of the survey areas, and up to 0.81 of the variance in Washington State waters. These negative correlations provide a possible predictive index for octopus abundance as measured by targeted visual surveys. These methods may be useful tools in management of octopuses and indicate impacts of climate change on North Pacific coastal marine ecosystems.

Purpose Review octopus ocular anatomy and describe the histopathologic findings in three octopuses diagnosed with phakitis and retinitis. Animals Two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) with a history of ophthalmic disease. Methods A literature search was performed for the ocular anatomy section. Both eyes from all three octopuses, and two control eyes, were submitted for histopathologic evaluation. Hematoxylin and eosin stain was used for standard histopathologic evaluation; GMS stain was used to screen for fungi, gram stain for bacteria; and Fite's acid fast stain for acid fast bacteria. Results Anatomically, the anterior chamber of the octopus has direct contact with ambient water due to an opening in the dorsal aspect of a pseudocornea. The octopus lens is divided into anterior and posterior segments. The anterior half is exposed to the environment through the opening into the anterior chamber. Neither part of the lens has a lens capsule. The retina is everted, unlike the inverted vertebrate retina, and consists of just two layers. Histopathology revealed inflammatory phakitis and retinitis of varying severity in all six eyes of the study animals. No intraocular infectious organisms were recognized but one common octopus eye had clusters of coccidian parasites, identified as Aggregata sp., in extraocular tissues and blood vessels. Conclusion We describe inflammatory phakitis and retinitis in two species of octopuses. The underlying cause for the severe intraocular response may be direct intraocular infection, water quality, an ocular manifestation of a systemic disease, or natural senescence.

Cephalopods are increasingly viewed as sentient animals that require the same welfare consideration as their vertebrate counterparts. In this study, an observational welfare assessment tool developed by the EU Directive was revised to be species-specific for the giant Pacific octopus, Enteroctopus dofleini. This E. dofleini health and welfare assessment tool includes categories assessing E. dofleini external appearance, behavior, and clinical signs of stress and disease. These categories are scored in severity from 1 to 4, allowing a quantitative perspective on health observations. Six facilities used the health and welfare assessment tool to evaluate E. dofleini until the animal was humanely euthanized or died naturally. Results showed an irreversible upward trend in scores for feeding behavior and response to stimulus beginning 4 weeks prior to death, with significant changes in health and welfare scores between 4 weeks and the final week prior to death. This suggests that upward trends in these two variables predict death within 3-4 weeks. Highly variable results between individuals for other categories indicate that a quantitative tool can help assess health and welfare at the individual level.

Understanding the trophic ecology of the giant Pacific octopus Enteroctopus dofleini is challenging in developing marine ranches and in reestablishing its regional stocks against the severe stress of fishing. We adopted carbon and nitrogen stable isotope techniques (termed δ13C and δ15N, respectively) to identify the trophic niche (i.e., pathways and positions) of this species systematically in the entire food webs of two marine ranches off the east coast of the Korean peninsula. While a slight spatial shift in the isotopic nestedness of faunal communities was observed, the δ13C and δ15N values of consumers were distinct and separate among functional groups at both ranches. The consumer δ13C values spanned a broad range between pelagic and benthic sources of organic matter, and their δ15N values recorded a stepwise trophic-level enrichment, indicating that suspension feeders and herbivore-deposit feeders served as baselines of pelagic- and benthic-based trophic pathways, respectively. The δ13C values of predators, including E. dofleini, were arrayed between the two primary consumer groups. Neither δ13C nor δ15N values showed any remarkable variations with increasing octopus weight. Dietary mixing-model calculations indicated that E. dofleini is a generalist predator relying on both benthic- and pelagic-affinity prey, similar to some teleost species that consume a diverse spectrum of prey. In contrast, other teleost groups showed prevalent trophic links with either pelagic- or benthic-based pathways. The trophic-level estimations revealed that E. dofleini occupies an intermediate position slightly below the teleosts. A lack of discrete trophic positions between E. dofleini and teleosts seemed to be indicative of the released teleost predation but instead reflects the imposed food competition. Overall, the results demonstrated that despite compositional changes in the taxa constituting individual trophic groups, E. dofleini occupied a very similar trophic niche in both ranching systems. Finally, as extracted from information based on octopus marine ranches launched on natural rocky bottoms, our isotopic evidence provides a greater understanding of the trophic ecology of this octopus species in nearshore natural habitats along the southwestern margin of its distribution range.

In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

Urbanization is a process that heavily alters marine and terrestrial environments, though terrestrial urban ecosystems have been studied far more intensively. Terrestrial studies suggest that urbanization can facilitate mesopredators by enhancing food and shelter resources and reducing predation pressure from apex consumers. This in turn has considerable consequences for ecological communities. We evaluated spatial distribution patterns and habitat-use of the marine mesopredator, giant Pacific octopus (Enteroctopus dofleini), relative to terrestrial urbanization intensity in Puget Sound, Washington, USA. Using field surveys and citizen-contributed data for E. dofleini, we examined whether: (1) Distribution was related to urbanization, (2) Abundance was related to the extent of benthic anthropogenic debris, and (3) Diet differed as a function of urbanization and den cover. Our results suggest that urbanization impacts may differ with depth. Mixed-effects logistic regression model estimates for the probability of occurrence increased with urbanization in deep-water (> 24 m), and decreased with urbanization in shallow water (< 18 m). Accompanying field surveys indicated that E. dofleini abundance was correlated with the number of benthic anthropogenic debris items, and that E. dofleini diets were not affected by urbanization intensity or den cover. Though E. dofleini may be synanthropic within certain urban environments, the mechanisms driving this pattern likely differ from those affecting common urban mesopredators on land, with den provisioning from man-made structures being more important than altered food resources.

There is a lack of information available on octopuses in Alaskan waters and because of this lack of data, catch limits are set based on historical incidental catch rates or survey biomass estimates that are likely to be overly conservative. This issue is further exacerbated by the fact that catch accounting for octopuses assumes 100% mortality for all octopuses caught whether retained or discarded. We examined the delayed mortality of the giant Pacific octopus, Enteroctopus dofleini , captured in Pacific cod, Gadus microcephalus , pot fisheries in the Gulf of Alaska. Octopuses captured as bycatch during commercial fishing operations were held on the vessel and brought back to the laboratory to assess delayed mortality over a period of 21 days. The relationship between survivorship and injury presence, sex, maturity, weight, season of capture, air temperature, water depth, and pot soak time were examined using generalized linear models. In addition, the relationship between injury presence and the same parameters were examined. Survivorship ranged from 77.8% to 93.6% during each of three fishing seasons and was significantly related to injury presence. Injury presence ranged from 10.0% to 63.2% during each season and was related to season with an increase in injuries during the fall. These data indicate the conservative assumption of 100% bycatch mortality for octopus is not appropriate for some fisheries, in particular those utilizing pot gear.

We tested whether body patterns distinguished two haplotypes of large octopus in Prince William Sound Alaska. Live octopuses were photographed in captivity and assigned to a morphotype based on whether longitudinal mantle folds (a characteristic body pattern feature of the giant Pacific octopus (GPO), Enteroctopus dofleini (Wulker 1910)) were present (the GPO morphotype, N = 14) or absent (a novel morphotype, N = 6). Novel morphotype octopuses were distinguished without exception from GPO morphotype octopuses by the presence of a lateral mantle frill and the absence of longitudinal mantle folds, ventral mantle texture below the lateral frill, and patch and groove patterning. Additional traits could be used in combination to reliably characterize the novel morphotype. The genetic haplotypes of these octopuses were determined from nucleotide sequence data from two microsatellite loci and a portion of the OCDE gene. The GPO morphotype was identified with E. dofleini based on the match of body pattern traits to published descriptions of that species and the match of its genetic haplotype to published sequences of E. dofleini. Novel morphotype body patterns did not match descriptions of any species from the eastern north Pacific, while its genetic haplotype matched that of a recently sequenced undescribed octopus. The GPO and novel morphotypes are sister clades, and body pattern traits reliably identified individuals to morphotype and haplotype. Body pattern traits can be used in field identification of live octopuses allowing population assessments, by-catch frequency estimates, and other studies of both octopus types. We offer the common name of the frilled giant Pacific octopus for the novel morphotype, and based on genetic and morphological data suggest this clade is a new species of large Pacific octopus in the genus Enteroctopus. A full species description remains to be done.

The endangered western stock of Steller sea lion (Eumetopias jubatus (Schreber, 1776)) still declines in the western Aleutian Islands and accurate diet information is vital to test leading hypotheses. We undertook the first bioenergetic diet reconstruction using both molecular and hard part prey identifications from >600 scats collected in March–April 2008 and 2012. Atka mackerel (Pleurogrammus monopterygius (Pallas, 1810)) remained a primary prey (17%–27% by energy), but large (mean 60 cm) Pacific cod (Gadus macrocephalus Tilesius, 1810) also emerged as important prey (20%–24%) in a more diverse diet than previously reported, with Cottidae and smooth lumpsucker (Aptocyclus ventricosus (Pallas, 1769)) also contributing ∼10%. DNA detections highlighted a potentially important and previously underestimated prey, giant Pacific octopus (Enteroctopus dofleini (Wülker, 1910) (diet contribution 2%–15%, dependent on prey size assumptions). Although 504 unique DNA identifications resulted in significant increases for cephalopods, Pacific cod, and smooth lumpsucker, hard part alone species rankings were similar to composite ones and bioenergetic species rankings similar to occurrence-based ones. Retention or regurgitation of large cephalopod beaks, the removal of large cod heads, and skeletal fragility of lumpsuckers may explain these differences. DNA identifications provide valuable comparative and complementary prey occurrence data for pinnipeds, but composite diet estimates are optimal.

Relationships between environmental factors and fluctuations in landing of North Pacific giant octopus(Enteroctopus dofleini Wulker, 1910) at Minamikayabe town, Hakodate city, Japan, during 1985-2016 were analyzed using regression analysis. Annual landings ranged between 165 and 403 tons, with an average of 273 tons. The relationship between landings and temperature was significant in 9 of the 24 months examined; 7 of the 9 occurred in catches 3-4 years after the temperature was measured. Rainfall showed no significant relationship with catch amounts. The results of the regression analyses suggest that landings of E. dofleini were related to ocean temperature, especially to temperatures 3-4 years before the landings occurred, presumably during the early part of the life cycle of the landed octopuses.

Octopus growth and movement occurs during all life stages and have implications for survival, food web dynamics and reproduction. From 2009 to 2011, 1714 North Pacific giant octopus (Enteroctopus dofleini) were tagged and recaptured in the eastern Bering Sea with visible implant elastomers to better understand the ecology of this data-poor species. Over this period, 246 of the tagged individuals were recaptured. In autumn, when temperatures were warmest, E. dofleini had higher growth rates and moved more than in the colder winter months. For both short- and long-term recaptures, small octopus grew faster than large octopus. Movement of octopus over short- and long-term periods was low for very small and very large octopus and high for median-sized octopus, which is likely to be a function of maturity status and reproductive activities. Approximately 80% of recaptures moved less than 2 km from the initial tagging location for time periods up to a year, suggesting long-term site fidelity. As tempera...

Octopus are caught incidentally in several US federally-managed trawl, longline, and pot fisheries in Alaska. The majority caught are giant Pacific octopus Enteroctopus dofleini. Recent changes in fisheries management in Alaska have resulted in the creation of an octopus species complex with annual catch limits, leading to increased interest in management and catch accounting for this data-poor assemblage. This study characterized the incidental octopus catch in Alaska groundfish fisheries and the mortality rate of octopus caught and discarded at sea. Onboard fisheries observers collected data on octopus weight, sex, and condition at discard in a variety of Alaska groundfish fisheries from 2006 to 2011. A field study aboard a commercial pot-fishing vessel examined delayed mortality resulting from the capture process in giant Pacific octopus during routine pot fishing. Octopus incidental catch varied widely in size and condition at capture for various fishing gear types. Vessels fishing using pot gear captured larger octopus than vessels using longline or trawl gear. Initial condition at capture was best in pot gear, with over 90% of octopus discarded from pot vessels alive in excellent condition. Octopus taken in trawl gear had the highest immediate mortality rate, with 68–94% dead or injured at discard. Giant Pacific octopus held for 24–60 h following pot capture showed no signs of delayed mortality or decline in condition. These results suggest that assuming 100% mortality of discarded octopus may overestimate fishing impacts.

In 2012, the North Pacific Fishery Management Council adopted a consumption-based stock assessment method to determine catch limits for the non-target, multi-species octopus complex in the Bering Sea-Aleutian Islands (BSAI) fishery management area. The method uses Pacific cod (Gadus macrocephalus) diet data as a basis for estimating octopus complex natural mortality and minimum biomass. To enhance understanding of the predator-prey interaction between Pacific cod and octopus, we examined patterns of octopus consumption by Pacific cod using long-term stomach contents data from the eastern Bering Sea continental shelf, a large, ecologically unique subarea of the BSAI. Generalized additive modeling of octopus presence/absence in Pacific cod diets revealed distinct spatial, ontogenetic and seasonal consumption patterns. Prey octopus frequency of occurrence (FO) generally increased with bottom depth, latitude and Pacific cod fork length, and FO in the southern BSAI was lower during winter and spring than during summer. Prey octopus FO patterns may reflect overall consumption patterns and likely indicate long-term distribution patterns of small-sized (

Resource management is required in order to persistently use a limited aquatic resources. The authors give an example of Enteroctopus dofleini, in the Rumoi. It is necessary to know the amount for the resource management. It is possible to know the distribution of the catch from the operation area and the catch. 2.5 kg of the minimum catch in weight is used for assignment of a catch. Distribution divides a fishery into the grid of 100 square meters, and shows it. Fisherman will be operated from 1 times to 6 times on the day and a fishery will be performed multiple times in the same fishery in order to catch Enteroctopus dofleini. A track consists of a operation and a movement. Only a moving track is removed using an automatic extraction algorithm. When an automatic extraction algorithm was applied, compared with the result which carried out manual extraction the extraction rate of a fishery is 95%, and the difference of the number of individuals of calculated resources was within plus or minus one.

Life-history information regarding most cephalopod species is somewhat scarce, and information relating anatomical anomalies of cephalopods is even more limited. For octopus species, the few anomalies that have been reported include: arm bifurcations (Smith, 1907; Okada, 1965; Gonzalez & Guerra, 2006), fourtharm hectocotylus (Robson, 1929), hexapody (Toll & Binger, 1991), septapody (Gleadall, 1989), decapody (Toll & Binger, 1991), and double hectocotylization (Robson, 1929; Palacio, 1973). Most male octopus have a modified third right arm or hectocotylus that is specialized for passing sperm packets to females. The tip of this specialized arm, known as a ligula, is spoon-shaped bearing a seminal groove ending in a rounded calamus. There are only three species of octopus that typically have the hectocotylized arm on the third left arm instead of the third right: Scaeurgus unicirrhus, Euaxoctopus panamensis and Pteroctopus tetracirrhus (Palacio, 1973). In over one hundred years of research, double hectocotylization has been reported in only six individual cases in six different species of octopus including: Eledone cirrhosa (by Appellof, 1892), Octopus briareus (by Robson, 1929), Octopus vulgaris (by Palacio, 1973), Octopus selene (by Palacio, 1973), Octopus chierchiae (by Roy Caldwell, personal communication) and Octopus minor (by Higashide et al., 2007). In each case, the third right arm was hectocotylized, along with an additional arm from the right side of the body (unilateral hectocotylization) or a left arm (bilateral hectocotylization). mentation of double hectocotylization for the Enteroctopus dofleini cephalopod having double hectocotylization not including either the third right or left arm. MALACOLOGIA, 2013, 56(1 2): 297 300

Trials were performed with magnesium chloride, ethanol and eight more complex organic substances screened for their effect as immersion anaesthetics for small, medium and large octopus species commonly used as experimental animals in Japan: Amphioctopus fangsiao , Octopus vulgaris , and Enteroctopus dofleini , respectively. Four of the organics were synthetic compounds commonly used as fish anaesthetics (metomidate, MS-222, propoxate, and quinaldine sulphate) and four have been used on other invertebrates (chloretone, gallamine, phenoxetol, and nicotine sulphate). Urethane (no longer used because of its carcinogenic properties) was used as a reference anaesthetic because of its long history of success with octopuses. Best results for anaesthetic effect were obtained with magnesium chloride and ethanol (which mimicked the typical anaesthetic effects seen with urethane) although some resistance to full anaesthesia was observed with ethanol when water temperatures were 10 °C or below in winter. No successful anaesthetic effects were obtained with the fish anaesthetics: in particular, metomidate was toxic even at low concentrations. Similarly (at the temperatures tested), chloretone, nicotine sulphate and phenoxetol were ineffective as anaesthetics and had toxic effects. Substances used to date as anaesthetics for cephalopods are briefly reviewed and it is concluded that future investigations to improve the provision of stable, safe and reliable anaesthesia for cephalopods would probably benefit from combinations of higher doses for shorter exposure times, and the co-administration of two or more substances. Empirical testing is still required for application to different species and to define appropriate concentrations, temperature and pH ranges.

We investigated the population structure of the North Pacific giant octopus, Enteroctopus dofleini (Wulker, 1910) in Alaskan waters. Octopuses were collected from five locations (Dutch Harbor (DH; n ¼ 45), Kachemak Bay (KB; n ¼ 45), Prince William Sound (PWS; n ¼ 18), Glacier Bay (GB; n ¼ 33), and Stephen's Passage (SP; n ¼ 39)). All samples were sequenced at the cytochrome oxidase I (COI) locus of the mitochondrial genome. We identified two major mtDNA haplogroups. Sequence divergence ranged from 0.2 to 2.9%. Haplotypes were not distributed evenly among the sampled populations, producing an enigmatic pattern of population structure. We observed no genetic differen- tiation between DH, KB and GB, or between PWS and SP. FST was extremely high for all other pair- wise comparisons, ranging from 0.871-0.948. We did not observe an isolation-by-distance pattern or a strong clinal gradient in haplotype frequencies, as typically detected in other marine species. Strong genetic drift, serial bottlenecks or sweepstakes events may contribute to the pattern observed. The high level of sequence divergence observed at the COI locus could also suggest cryptic species within the E. dofleini complex, with limited geographical overlap of populations and gene flow. Additional samples were contributed by researchers from British Columbia (n ¼ 1), Seaside, Oregon (n ¼ 4), Neah Bay, Washington (n ¼ 2), Puget Sound, Washington (n ¼ 1), and Kodiak Island, Alaska (n ¼ 2)) While sample sizes were low for these locations, prompting their exclusion from population based analyses, all individuals were of the predominate haplotype found in Alaska.

The giant Pacific octopus (Enteroctopus dofleini) is a popular exhibit species in public display aquaria, but information on health and disease is limited. This retrospective review evaluates time in collection and describes antemortem clinical signs and pathology of giant Pacific octopuses in an aquarium setting. Between March 2004 and December 2013, there were 19 mortalities: eight males, 10 females, and one individual whose sex was not recorded. Average time spent in collection for all octopuses was 375 ± 173 days (males 351 ± 148 days, females 410 ± 196 days). Ten (52.6%) of the octopuses were sexually mature at the time of death, six (31.6%) were not sexually mature, and reproductive status could not be determined in three octopuses (15.8%). Minimal changes were noted on gross necropsy but branchitis was histologically evident in 14 octopuses, often in conjunction with amoeboid or flagellate parasites. Senescence, parasitism, and husbandry were all important contributors to mortality and should be considered when caring for captive octopuses.

Visible Implant Elastomer (VIE) tags represent a viable approach for long-term tracking of North Pacific giant octopus ( Enteroctopus dofleini ) in Alaska. Over a two year period, 1730 E. dofleini were tagged with individually identifiable VIE tags and 238 E. dofleini were recaptured in a 25 km 2 area. Of the 238 E. dofleini recaptured, 31 were at liberty for 60 days or more with a maximum time at liberty of 374 days. This study shows that long-term retention of VIE tags may prove to be a vital tool in determining important life-history information for octopus species.

Multiple species of large octopus are known from the north Pacific waters around Japan, however only one large species is known in the Gulf of Alaska (the giant Pacific octopus, Enteroctopus dofleini). Current taxonomy of E. dofleini is based on geographic and morphological characteristics, although with advances in genetic technology that is changing. Here, we used two mitochondrial genes (cytochrome b and cytochrome oxidase I), three nuclear genes (rhodopsin, octopine dehydrogenase, and paired-box 6), and 18 microsatellite loci for phylogeographic and phylogenetic analyses of octopuses collected from across southcentral and the eastern Aleutian Islands (Dutch Harbor), Alaska. Our results suggest the presence of a cryptic Enteroctopus species that is allied to, but distinguished from E. dofleini in Prince William Sound, Alaska. Existence of an undescribed and previously unrecognized taxon raises important questions about the taxonomy of octopus in southcentral Alaska waters.

Prey choice is often evaluated at the species or population level. Here, we analyzed the diet of octopuses of different populations with the aim to assess the importance of individual feeding habits as a factor affecting prey choice. Two methods were used, an assessment of the extent to which an individual octopus made choices of species representative of those population (PSi and IS) and 25% cutoff values for number of choices and percentage intake of individual on their prey. In one population of Octopus cf vulgaris in Bermuda individuals were generalist by IS=0.77, but most chose many prey of the same species, and were specialists on it by >75% intake. Another population had a wider prey selection, still generalist with PSi=0.66, but two individuals specialized by choices. In Bonaire, there was a wide range of prey species chosen, and the population was specialists by IS= 0.42. Individual choices revealed seven specialists and four generalists. A population of Octopus cyanea in Hawaii all had similar choices of crustaceans, so the population was generalist by IS with 0.74. But by individual choices, three were considered a specialist. A population of Enteroctopus dofleini from Puget Sound had a wide range of preferences, in which seven were also specialists, IS=0.53. By individual choices, thirteen were also specialists. Given the octopus specialty of learning during foraging, we hypothesize that both localized prey availability and individual personality differences could influence the exploration for prey and this translates into different prey choices across individuals and populations showed in this study.

We examined variation in dietary specialization of Enteroctopus dofleini (Wulker, 1910), the giant Pacific octopus, from Puget Sound to the Aleutian Islands, as represented in midden remains. Dietary specialization was measured from midden contents as: species richness (R) and Cardona's niche breadth (regional indices), and proportional similarity of a midden to the regional sample (an individual index). We found an influence of items per midden and prey species maximum size on these indices. In Puget Sound, middens and common prey species were large, richness, R = 21 species, and individuals specialized more often than in other areas, typically on large prey species. In Saanich Inlet, British Columbia, middens were smaller, R = 9 species, and the large crab Cancer productus was common in nearly all middens, such that the population specialized rather than the individual. In Prince William Sound, Alaska, middens contained fewer individuals of smaller prey species, R = 52 species, and diet was ge...

This study was performed to promote the effective utilization of edible marine resources and to develop functional food material from edible marine resource extracts for inhibiting lipid accumulation in liver. Edible marine resource extracts (ME) were prepared by hot water (MWE) and 80% ethanolic (MEE), and both the MWE and MEE extracts were assessed as to their cell cytotoxicity, and Oil Red O staining. Results demonstrated that ME showed no cytotoxic effects. However, treatment with MEE in the concentration of 1000, 500, and 250 µg/mL significantly inhibited the lipid accumulation in HepG2 cells compared to MWE. Especially, among the 80% ethanolic extracts, Pagrus major, Larimichthys polyactis, Clupea pallasii, Octopus minor, Enteroctopus dofleini, Styela clava, dried sea mustard, and Enteromorpha intestinalis showed greater lipid accumulation inhibitory activity than the others.

We attached sonic transmitters to, and tracked, 40 giant Pacific octopuses (Enteroctopus dofleini) ranging from 83% retention to the end of a tracking period (range 18 to 48 h. Direct movements (indicating relocation or den-switching) were common at night, central-tendency movements (indicating localized area use and return to den) were common at dawn, and stationary behavior was common in daylight, although each pattern occurred at all periods. Central-tendency movements recorded by intermittent tracking were oriented parallel to contours, while movements without central tendency crossed contours, suggesting that animals navigate by contour-following to return to a known den. During a relocation experiment, octopuses released at shallow depths moved deeper and those released deeper moved shallower; both into habitats with greater kelp cover. Although >90% of their time was spent stationary and hiding, Enteroctopus dofleini utilizes information about its environment (contour following), selects habitats (preference for more kelp cover), and occupies large use areas (minimum convex polygons) by making substantial direct movements from previous use areas.

We isolated and developed 18 novel microsatellite markers for the giant Pacific octopus (Enteroctopus dofleini) and examined them for 31 individuals from Prince William Sound (PWS), Alaska. These loci displayed moderate levels of allelic diversity (averaging 11 alleles per locus) and heterozygosity (averaging 65%). Seven loci deviated from Hardy–Weinberg Equilibrium (HWE) due to heterozygote deficiency for the PWS population, although deviations were not observed for all these loci in other populations, suggesting the PWS population is not in mutation-drift equilibrium. These novel microsatellite loci yielded sufficient genetic diversity for potential use in population genetics, individual identification, and parentage studies.

2003 年 10 月から 2004 年 12 月に，宗谷海峡で漁獲されたミズダコの成熟状態の季節変化を明らかにした。雌では，既交接個体の体重に対する生殖器官重量が秋から翌年春にかけて顕著に増大し，その結果，体重と生殖器官重量との関係が異なる 2 群が認められた。同様に，雄でも精莢を所持していた個体の生殖器官重量が秋から翌年春に顕著に増大して，2 群が認められた。宗谷海峡のミズダコ産卵期を初夏とすれば，生殖器官の肉眼的観察項目に加えて，体重と生殖器官重量の関係に基づいて産卵年および交接年を区分することが可能である。

There are several references to octopuses eating birds but few give details of the encounters. Here we document the details of seven instances (six Enteroctopus dofleini (Wulker, 1910) and one Octopus cf. insularis Leite and Haimovici, 2008) of octopuses attacking, capturing or eating birds, including glaucous-winged gulls (Larus glaucescens), a pigeon guillemot (Cepphus columba), a double-crested cormorant (Phalacrocorax auritus), a western grebe (Aechmophorus occidentalis) a brown noddy (Anous stolidus) and a bald eagle (Haliaeetus leucocephalus).

The captive husbandry of giant Pacific octopuses Enteroctopus dofleini is well understood, but their endocrine signatures are not well documented. The major vertebrate reproductive hormones--estrogen, progesterone, and testosterone--and the stress-related hormone corticosterone are relatively well known for many vertebrate species. However, few studies on these hormones within invertebrates have been conducted. Our hypothesis was that endocrine signatures within octopuses are similar to those found within vertebrates in response to reproductive activity and stress. Using standard immunoassay techniques, we measured fecal steroids within fecal samples collected from five female and three male giant Pacific octopuses housed at the Seattle Aquarium. The mean estrogen level ranged from 3.67 to 99.39 ng/g of feces, progesterone ranged from 44.35 to 231.71 ng/g feces, testosterone ranged from 9.30 to 18.18 ng/g feces, and corticosterone ranged from 10.91 to 22.14 ng/g feces. The results suggest that octopus fecal hormones are similar to those in vertebrates and may be useful in measuring ovarian activity and stress within captive female giant Pacific octopuses.

This study exposed 8 Enteroctopus dofleini separately to 2 unfamiliar individual humans over a 2-week period under differing circumstances. One person consistently fed the octopuses and the other touched them with a bristly stick. Each human recorded octopus body patterns, behaviors, and respiration rates directly after each treatment. At the end of 2 weeks, a body pattern (a dark Eyebar) and 2 behaviors (reaching arms toward or away from the tester and funnel direction) were significantly different in response to the 2 humans. The respiration rate of the 4 larger octopuses changed significantly in response to the 2 treatments; however, there was no significant difference in the 4 smaller octopuses' respiration. Octopuses' ability to recognize humans enlarges our knowledge of the perceptual ability of this nonhuman animal, which depends heavily on learning in response to visual information. Any training paradigm should take such individual recognition into consideration as it could significantly alter the octopuses' responses.

This study was conducted to investigate the reason for the increase in the antioxidant activity of cooking drip from Enteroctopus dofleini by gamma and electron-beam irradiation. To define the effect of irradiation on the antioxidant activity of polyphenol in cooking drip, polyphenol excluded cooking drip extracts were prepared with polyclar™. But, the antioxidant activity of the cooking drip extracts without polyphenol was still increased by both irradiations. Instead, the effect on the proteins in the cooking drips prepared by ammonium sulfate precipitation showed great increase in antioxidative activity by irradiation. From these results, it was concluded that the increase in the antioxidative activity in cooking drips by the irradiation was caused by the structural modification of proteins in the cooking drips.

A species of dicyemid mesozoan is redescribed from the giant Pacific octopus, Enteroctopus dofleini (Wülker, 1910), collected off Iwase in Toyama Bay, Honshu, Japan. Dicyemennea nouveli McConnaughey, 1959, is a large species that reaches about 12,000 microm in length. This species lives in folds of the renal appendages. The vermiform stages are characterized as having 30-41 peripheral cells, a conical calotte, and an axial cell that extends to the middle of the metapolar cells. An anterior abortive axial cell is present in vermiform embryos. Full-grown vermiform embryos have as many as 4 agametes. Infusoriform embryos consist of 39 cells; 2 nuclei are present in each urn cell and the refringent bodies are solid.

Physiological activities of the 70% ethanol extract from boiled-water of Enteroctopus dofleini (BE) upon a gamma irradiation were determined to examine the possible use of the food processing by-product as a functional material for food or cosmetic composition. Electron donating ability and the content of total phenolic compounds increased from 65% to 72% and from 406 ppm to 476 ppm, respectively, by 10 kGy gamma irradiation. A Salmonella mutagenicity assay indicated that the gamma-irradiated BE did not show any mutagenicity. Tyrosinase inhibition activity of the irradiated BE also increased from 57% to 86% with irradiation doses. These results show that irradiation can be used to increase the physiological activities of BE for its potential use as food or cosmetic materials.

A total of 77 giant Pacific octopus, Enteroctopus dofleini, tissue samples were collected from the Oregon Coast (OR), Neah Bay Washington (NB), Puget Sound Washington (PS) and the southeast coast of Vancouver Island, British Columbia, Canada (BC) for genetic analyses. A suite of eight variable microsatellite markers developed from giant Pacific octopuses were amplified in these samples to determine population diversity, structure, relatedness and paternity. The majority of loci met Hardy-Weinberg equilibrium expectations within each population. We found moderate genetic diversity (average observed heterozygosity = 0.445, range = 0.307–0.515 and average expected heterozygosity = 0.567, range = 0.506–0.696) and moderate population structuring with distinct separation of groups (FST values ranged from 0.101 between BC and PS to 0.237 between BC and NB). Several egg strings from the BC population were collected from three female octopus dens for relatedness and paternity analyses. Results suggest strong support for multiple paternity within one egg clutch with progeny sired by between two to four males.

There are several reports that chondroitin sulfate containing K-type units [GlcA (3S)-GalNAc (4S)] exhibiting similar levels of neurite outgrowth promoting activities as CS having high amounts of B-, D- and E-type disulfated disaccharides. Although CS containing K-type units possess important biological activities, there are only few sources, such as king crab cartilage, squid cartilage or sea cucumber. In this study, CS containing 13.9% of K-type units was found in octopus (Enteroctopus dofleini) cartilage using different substrate specificities of chondroitinases. The 2D NMR spectra showed cross-peaks assigned to protons on sugar ring of GlcA (3S), demonstrating the presence of K-type units in octopus CS. Furthermore, proportion of fucosylated disaccharide units in octopus CS was very low. Octopus CS showed high affinity for growth factors and stimulated neurite outgrowth of hippocampal neurons, similar to the activity of squid CS-E. These results strongly suggest that octopus cartilage is a rich source of CS-K and has important biological activities.