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Cephalopods are harvested in increasingly large quantities but understanding how to control and manage their stocks, and tracking the routes of the consumption that exploits them, lag behind what has been developed for exploiting finfish. This review attempts to redress the imbalance by considering the status of the major cephalopod stock species and the traceability of cephalopod seafood along the trade value chain. It begins with a general overview of the most important exploited cephalopods, their stock status and their market. Four major cephalopod resources are identified: the three squid species Todarodes pacificus , Dosidicus gigas and Illex argentinus ; and one species of octopus, Octopus vulgaris . The techniques and problems of stock assessment (to assess sustainability) are reviewed briefly and the problems and possible solutions for assessing benthic stock such as those of octopuses are considered. An example of a stock well managed in the long term is presented to illustrate the value of careful monitoring and management: the squid Doryteuthis gahi available in Falkland Islands waters. Issues surrounding identification, mislabelling and illegal, unreported and unregulated (IUU) fishing are then reviewed, followed by a discussion of approaches and techniques of traceability as applied to cephalopods. Finally, some of the mobile apps currently available and in development for tracking seafood are compared. This review concludes with observations on the necessity for the strengthening and international coordination of legislation, and more rigorous standards for seafood labelling and for taxonomic curation of DNA sequences available in public databases for use in seafood identification.

The cephalopod receptor of particle motion was identified. In a previous study, it was suggested that statocysts served this function, but there was no direct supporting evidence, and epidermal hair cells had not been conclusively ruled out. Experiments on Octopus ocellatus were conducted using respiratory activity as an indicator of sound perception. Intact animals clearly responded to 141-Hz particle motion at particle accelerations below 1.3×10 −3 m/s 2 , and the mean perception threshold at this frequency was approximately 6.0×10 −4 m/s 2 . Specimens in which the statoliths had been surgically removed did not show any response for accelerations up to 3.9×10 −3 m/s 2 at 141 Hz, which was approximately 16 dB greater than the mean perception threshold at this frequency. Specimens that had undergone a control operation in which the statoliths remained intact showed positive responses at 2.8×10 −3 m/s 2 for the same frequency stimulus. This indicates that the statocyst, which is morphologically similar to the inner ear system in fish, is responsible for the observed responses to particle motion in O. ocellatus . This is the first direct evidence that cephalopods detect kinetic sound components using statocysts.

Octopuses (Octopus vulgaris) landed from commercial fishing were sampled and the concentrations of lead, calcium and strontium, in digestive gland, branchial heart, gills, mantle and arms, were determined using PIXE (particle-induced X-ray emission). Lead was detected in all tissues, although not in samples from all animals analysed. Female octopuses accumulated more lead in digestive gland than did males. The digestive gland index, an indicator of nutritional status, showed a negative correlation with lead concentration in both sexes. There were positive correlations between the concentration of lead and those of calcium and strontium in digestive gland and a negative correlation between lead and calcium in branchial heart tissue. Concentrations of calcium in arms were lower in autumn and spring than in winter and summer. Lead content increased with increasing body weight and mantle length so we can conclude that lead continues to accumulate during the animal's life. Concentrations of lead in two samples were higher than the maximum legally permitted concentration of lead in food.

Wastewaters from fish-canning industries have a high concentration of organic polluting substances (10-50 g chemical oxygen demand${\\rm L}^{-1}$[COD]) and, in some cases, a high content of sea salts (${\\rm Cl}^{-}$: 8-19 g${\\rm L}^{-1}$,${\\rm Na}^{+}$: 5-12 g${\\rm L}^{-1}$,${\\rm SO}_{4}^{2-}$: 0.6-2.7 g${\\rm L}^{-1}$). The presence of high sodium ion concentrations in wastewaters with high organic content traditionally is considered as a very negative factor for their anaerobic treatment. In fact, both the presence of${\\rm Na}^{+}$and${\\rm SO}_{4}^{2-}$, transformed into${\\rm H}_{2}{\\rm S}$during the anaerobic degradation process, may cause toxicity and inhibition on the methanogenic process. This work deals with the operation and treatment efficiency of two lab-scale mesophilic and thermophilic anaerobic filters (MAF and TAF, respectively). So that the adaptation of anaerobic sludge to high saline concentrations is attained, a prolonged start-up period of about nine months was necessary. After this, a stable operation and similar treatment efficiencies were reached, even when organic loading rate (OLR) as high as 9 kg COD${\\rm m}^{-3}$ ${\\rm d}^{-1}$(TAF) or 24 kg COD${\\rm m}^{-3}$ ${\\rm d}^{-1}$(MAF) were applied at chloride concentration of 13 g${\\rm L}^{-1}$. At these conditions, the COD removal reached 73% (TAF) and 64% (MAF), and the COD methanized reached 69% (TAF) and 66% (MAF). The sulphate in the influent was removed practically completely, leading to a${\\rm H}_{2}{\\rm S}$concentration in the biogas between 3-4%. In spite of the lower specific activity of sludge from MAF (0.21 g COD${\\rm g}^{-1}$volatile suspended solids [VSS]${\\rm d}^{-1}$) than from TAF (0.66), the MAF reached a higher OLR than TAF. This fact can be explained because of the higher retention of sludge into MAF (72 g VSS${\\rm L}^{-1}$) than TAF (10 g VSS${\\rm L}^{-1}$). Two practical conclusions may be derived from this work: the thermophilic operation needs the use of a packing material with a higher capacity to retain biomass and the mesophilic operation requires a more frequent detachment of biomass from the support in order to avoid clogging problems.

A comprehensive survey of the octopus fauna around the Americas is presented to facilitate and accelerate the assessment of a full understanding of American octopus biodiversity. Brief accounts are provided summarizing research efforts on octopus species taxonomy, diversity and distribution in different regions of North and South America. Octopus americanus and O. insularis are compared and clearly distinguished from each other and from the closely-related European species, O. vulgaris. The use of genus names Paroctopus and Pinnoctopus is clarified. Included is a discussion of the recent application of genus name Paroctopus to warm-temperate and tropical species of small size, along with a cautionary note about species identifications in the light of past errors in misassigning large-to-giant cold-water species to genus Paroctopus. Related to problems with identifying species of Paroctopus, there is an appended note concerning misidentifications and the importance of thorough species descriptions to obtain species information at the levels of both phenotype and genotype. A lectotype is formally designated for Bathypolypus arcticus (Prosch, 1849); and the status of so-called ‘Octopus giganteus’ is reviewed briefly. A supplementary online database, AmeriCeph, provides basic information about all known octopus species of the Americas, including the institutional location of type material and the identification of voucher specimens and their depositories. DNA sequences registered in this database are not all fully compatible with barcoding standards. However, a subset of DNA sequences conforming to strict barcode identifications is provided in a second supplementary table, providing barcode sequences directly applicable also to improving standards of seafood traceability. This in turn contributes to building sustainability of exploited octopus fisheries stocks and identification of species suitable for aquaculture trials to meet the increasing commercial demand for octopus worldwide.

Over 150 species of benthic octopods have been described within the ‘catch-all’ Octopus genus (Family: Octopodidae) and yet, many Octopus species harvested by fisheries remain unidentified to species-level due to a lack of distinguishing traits. Within species, there is also limited information on how populations differ genetically and the level of connectivity between populations. Therefore, we sampled octopods from commercial fisheries in southeast Australia, in order to identify the species, examine the phylogeographic relationships among species and the level of population genetic structuring within species, as well as to look for any adaptive genetic variation. The mitochondrial gene, cytochrome oxidase subunit III (COIII), was sequenced in 346 octopods along with single nucleotide polymorphisms using double digest restriction site-associated DNA sequencing (ddRADseq). Morphometric traits were also measured in mature specimens. The southern keeled octopus (‘Octopus’berrima) and pale octopus (‘Octopus’pallidus) were identified using COIII data. For ‘Octopus’berrima, we found that some populations whilst being morphologically similar were genetically distinct. In contrast, ‘Octopus’pallidus populations were both morphologically and genetically distinct across the studied regions. Our results provide key information to better inform conservation and management decisions for developing octopod fisheries in southeast Australia and highlight the importance of genomics tools in the conservation management of commercially and recreationally important species.

Octopuses present a difficult resource to manage because of their relatively short life spans, rapid growth rates, high natural mortality and seasonal fluctuations in abundance. With exploitation efforts increasing worldwide, particularly in the Pacific Island region, substantial knowledge gaps in their biology, exploitation and management remain. We conducted a literature review to summarise their species distribution, abundance, ecological attributes, utilization, importance and management within the Pacific Island Countries and Territories (PICTs) of Fiji, Vanuatu, the Solomon Islands, New Caledonia, Tonga, Samoa and American Samoa. We found that 23 species of octopuses within 11 genera were recorded from these PICTs, belonging to the families Amphitretidae and Octopodidae. Overall, Tonga was the most speciose country with 11 occurrence records and Samoa recorded the least with just a single species. All other countries recorded between 2 and 8 taxa. The day octopus (Octopus cyanea) was recorded from all PICTs except Samoa. There are no specific national regulations on octopus fisheries within the PICTs and management is largely dependent on overarching national fisheries legislation. However, community-based management efforts can be an effective platform in sustaining octopus stocks. Octopuses also play an important role in the folklore and customs of many Pacific Islanders, and we provide a summary of these for the specific PICTs assessed. This review highlights areas for further research and development for the Pacific Island region and the urgent need to address specific knowledge gaps on octopus taxonomy, stock assessment and fishery management.

The octopus of the genus Tremoctopus from the Arabian Sea has not been investigated in the past. This study reports on the rare pelagic octopus Tremoctopus gracilis from the south-eastern Arabian Sea. Twenty females with dorsal mantle lengths (DML) ranging between 62 and 160 mm and weighing between 31 and 719 g were examined. These specimens were collected from commercial fishing grounds, and amongst them was a single mature female with 12,618 oocytes in the ovary (size varied from 0.61 to 1.67 mm (mean = 1.13 mm). The detailed morphometric and morphological characteristics were recorded, and the specimens were identified up to the genus level. Further molecular species identification was carried out through mitochondrial markers (COI & 16S rRNA). Phylogenetic analysis, based on partial sequences of the above markers, generated a single clade that included sequences from the Indian and Pacific Oceans, including those misidentified as Tremoctopus violaceus from the Pacific. Evolutionary divergence estimation revealed a high inter-specific genetic divergence from T. violaceus sequences in the Mediterranean Sea and Atlantic Ocean, thus confirming the Tremoctopus species in our study as T. gracilis and authenticated that GenBank sequences of T. violaceus from the Pacific Ocean are indeed T. gracilis .

Among mollusks, the octopods stand out due to the almost entire absence of a stabilizing shell, potentially rendering these organisms susceptible to deformation caused by fixation and preservation. Such artifacts have previously been shown to occur especially in specimens of the deep-sea taxon Cirrata, the finned octopods. As an adaptation to their extreme habitat, many cirrates are composed of (semi-)gelatinous tissues, which are particularly prone to distortion, shrinkage, and deformation following fixation and preservation. Using one or more species from each of the eight currently recognized cirrate genera, the present study provides pre- and post-fixation color imagery of entire specimens as well as measurements of taxonomically relevant characters. These novel data illustrate the sometimes drastic effects that short- and long-term chemical treatment entails for this cephalopod taxon. Both structural and color changes may occur when finned octopods are fixed and preserved using routine protocols. However, shrinkage does not occur uniformly in all taxonomically relevant structures. The consequences of such a treatment for species descriptions and identification are discussed and existing anaesthetization, fixation and preservation protocols are summarized.