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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

Knowledge of recruitment to a fishery is particularly important in short-lived species, like most cephalopods, in which there is a complete turnover of individual every 1 or 2 years. In this study, age, body length, statolith length and growth rates of loliginid paralarvae (Alloteuthis media, A. subulata and Loligo vulgaris) were determined to evaluate the form of the growth curve and differences between species and hatching seasons. A total of 222 paralarvae collected in zooplankton samples along the Galician coast (NW Spain) were used to determine relationships between dorsal mantle length (DML), statolith length (SL) and the number of increments (NI)) deposited in the statolith. The paralarvae of L. vulgaris were between 1 and 35 days old, while both Alloteuthis species ranged in age from 1 to 54 days. Generalised additive models (GAMs) revealed non-linear growth in DML, with L. vulgaris exhibiting higher DML-at-age than Alloteuthis species. The best parametric model fit for these data was obtained using exponential regressions. The SL–NI relationship also differed between species, with L. vulgaris having larger statolith length at age. The paralarvae of L. vulgaris and A. media had two well-differentiated hatching peaks, one in late spring-early summer (beginning of the upwelling season) and another peak in late autumn (end of the upwelling season). Alloteuthis subulata had an earlier hatching peak in spring than in the other two loliginid species—and the second peak in autumn was barely visible, possibly because this species occurs further north in areas not sampled in autumn

The Falkland Shelf is a highly productive ecosystem in the Southwest Atlantic Ocean. It is characterized by upwelling oceanographic dynamics and displays a wasp-waist structure, with few intermediate trophic-level species and many top predators that migrate on the shelf for feeding. One of these resident intermediate trophic-level species, the Patagonian longfin-squid Doryteuthis gahi, is abundant and plays an important role in the ecosystem. We used two methods to estimate the trophic structure of the Falkland Shelf food web, focusing on the trophic niche of D. gahi and its impacts on other species and functional groups to highlight the importance of D. gahi in the ecosystem. First, stable isotope measurements served to calculate trophic levels based on an established nitrogen baseline. Second, an Ecopath model was built to corroborate trophic levels derived from stable isotopes and inform about trophic interactions of D. gahi with other functional groups. The results of both methods placed D. gahi in the centre of the ecosystem with a trophic level of ~ 3. The Ecopath model predicted high impacts and therefore a high keystoneness for both seasonal cohorts of D. gahi. Our results show that the Falkland Shelf is not only controlled by species feeding at the top and the bottom of the trophic chain. The importance of species feeding at the third trophic level (e.g. D. gahi and Patagonotothen ramsayi) and observed architecture of energy flows confirm the ecosystem's wasp-waist structure with middle-out control mechanisms at play

Bycatch of cetaceans by European Union (EU) fleets is mostly monitored by onboard observers under the EU Data Collection Framework (DCF) programme. There is concern that the resulting estimates of cetacean bycatch mortality are biased and imprecise, because bycatch events are rare, sampling coverage is limited, and DCF observers prioritize the sampling of the discard of commercial species. Here, we explore the utility of the recently established Spanish cetacean bycatch monitoring programme to estimate cetacean bycatch mortality and compare it to the EU DCF programme. Data from October 2020 to September 2021 from this new Spanish programme were analysed to explore the following issues: (i) representativeness of the sampling frame; (ii) estimation of bycatch per unit of effort (BPUE); and (iii) sampling coverage. The probabilistic sampling design of the programme, with a record of refusals, has allowed identification and correction of biases in BPUE estimation. BPUE estimates for the bottom pair trawl fleet were recalculated to account for the fact that although boats work in pairs, each pair is monitored by a single observer located in a single boat. In relation to the sampling coverage, our results point to a need for levels up to 31% to achieve statistically robust bycatch rates. The current Spanish EU DCF at-sea sampling programme (which includes the sampling of bycatch of non-target protected species) and the Spanish (dedicated) cetacean bycatch monitoring programme provided similar results on cetacean bycatch for some of the ICES Divisions and Metiers monitored but sampling coverage of both is insufficient to obtain robust estimates.

Diet studies on the endangered and genetically distinct Iberian population of the southern harbour porpoise Phocoena phocoena are scarce. The present study provides updated information on the feeding ecology of this cetacean along the Galician coast (NW Spain) over the last 3 decades (1990-2018). The stomach contents of 72 stranded harbour porpoises were analysed to determine diet composition, to study which factors affect dietary variability and to estimate overlap between harbour porpoise diet and the target species of the fisheries in the study area, one of the most important fishing regions in Europe. Results showed that harbour porpoises are mainly piscivorous. We identified 33 prey taxa, but only 4 were important in the diet: fish of the genus Trisopterus, blue whiting Micromesistius poutassou, Atlantic horse mackerel Trachurus trachurus and European hake Merluccius merluccius. Interannual and ontogenetic variability in the diet were statistically significant, although differences in diet between sexes or between seasons were not detected. The diet of harbour porpoises from the Galician coast shows a partial overlap with fisheries catches in the area in terms of commercial fish species (≈61%) and size classes (≈45%), confirming the potential vulnerability of the Iberian population to interactions with fishing activities (i.e. bycatch in fishing gear and/or reduced prey availability)

The common octopus, Octopus vulgaris Cuvier, 1797, is a meroplanktonic species with planktonic hatchlings and bentic juveniles and adults, which is found throughout the northeast and eastern central Atlantic Ocean, including central Atlantic islands and the Mediterranean Sea. [...]

Information on fishing effort by vessels fishing with traps in Scotland is limited. The recent availability of VMS data combined with landings information from vessel logbooks provides new opportunities to describe the spatial distribution of effort and catch for data-limited fisheries. This study evaluates the use of VMS data applied to trap fisheries and estimates an indicator of fishing effort for the offshore brown crab fishery in Scotland. VMS data seem to provide a valid basis for calculating effort (time fishing), assuming that fishing can be distinguished from other activities by selecting an appropriate speed range. Comparisons between high and low temporal resolution data show that the standard 2-hour transmission interval of VMS data introduces substantial uncertainty into effort estimates. Assumptions related to the relationship between fishing time and the number of creels fished, and on assigning catch data to VMS positions, were explored. The areas to the north of Scotland are the main target of the offshore brown crab fleet. Landings and effort by offshore crab vessels have generally increased up to 2016–2018 followed by a clear reduction in the last 3–5 years. The brown crab LPUE trend in this study was found to be similar with that obtained from indices based on survey data. Effort and LPUE estimates may be used to identify and inform managers of the main fishing areas for offshore vessels targeting brown crab and can also be applied to fisheries for other data-limited species, provided that VMS or other GPS logger systems are available. The methodology implemented in this study is sensitive to the temporal resolution of the data collection systems. Systems capable of providing higher temporal resolution data would be desirable, to obtain more accurate estimates of fishing effort

Knowledge of the diet of marine predators such as seabirds is fundamental to understanding the ecological cascades they may influence and the impact that environmental changes may have on them. Diet analysis of seabirds frequently relies on the identification of fish otoliths in pellets. However, it is recognised that the true dietary importance of fish with small and fragile otoliths is likely underestimated, requiring an additional method. In this study, we compared the identification of otoliths with that of vertebrae in pellets to gain a more complete picture of seabird diet. We identified fish otoliths and vertebrae from 2584 great skua Stercorarius skua pellets collected between 2014 and 2017 from five colonies in Scotland. Diet varied markedly between colonies, comprising mostly fish in Shetland and mostly birds in St Kilda. 10% of pellets contained otoliths compared to 70% with fish vertebrae. Atlantic herring Clupea harengus and Atlantic mackerel Scomber scombrus were the most common fish species at all colonies when using vertebrae in contrast to being virtually absent when using otoliths. Conversely, the occurrence of Norway pout Trisopterus esmarkii and pollock Pollachius pollachius otoliths was six and eight times, respectively, higher than for vertebrae. Therefore, combining data from both otoliths and vertebrae provides a more complete profile of the fish component of seabird diet. This is fundamental to improving our understanding of the impacts of marine management policies on seabirds, as well as how changes in the population size of such seabird species might affect their prey species

This chapter describes past and present publication trends in octopus research following a systematic mapping approach. Publication rates in popular research topics such as life history and ecology are decreasing, while others are increasing and taking the spotlight. Interest in behaviour has seen a considerable uptick in recent years. Also, rapid advances, emerging tools, and widespread access to DNA sequence information have stimulated an increased focus on topics relating to genomics & evolution. Research related to diversity & bBiogeography is also increasing, especially in the context of the concurrent biodiversity and climate crises. Although global change represents the least studied topic to date, interest has increased tremendously over the past 5 years, with more than double the publication rate observed for behaviour (the topic with the second largest publication rate). Our analysis also provides a geographical perspective; the food and argriculture organization region with the most octopus-related studies is the Mediterranean, followed by the Northeast and Western-Central Atlantic Ocean. Regarding species of interest, Octopus vulgaris stands out as the overwhelming front-runner representing more than half of all records and over five times more than the second most studied species, Octopus maya. We also provide a discussion on future directions for key subjects, including behaviour and cognition, iEcology and citizen science, bio-robotics, deep-sea research, climate change, and culture and welfare, among others, with the hope of providing an agenda for future research

Study of the diet of squid is hampered by the fact that these animals masticate their prey prior to ingestion and do not necessarily ingest the hard parts that allow the identification of prey remains present in the stomach. The result is a large percentage of prey in stomach contents that can be identified only according to broad categories (e.g., “teleost fish”). This is widely described in the literature and has also been found in samples from the English Channel of the two loliginid squid fished in this area (Loligo forbesii and Loligo vulgaris). New biological samples of both species were collected at the Port-en-Bessin fish market during the 2019–2020 fishing season. Stomach contents were studied through DNA metabarcoding targeting a small fragment of the COI mitochondrial gene selected by PCR and sequenced using high-throughput next generation sequencing. The DNA metabarcoding results were compared with databases available online. These preliminary results validated a protocol based on commercial samples kept frozen (−20 °C) before analysis. Sequences allowed 34 different types of prey to be identified to the species level, including 17 teleost fish species. Results revealed the high occurrence of cuttlefish eaten by both species of squid. Food composition was analysed in order to make comparisons between species, between seasons (in L. vulgaris) and according to the size of the predator. Differences in diet of L. vulgaris between November and March samples were greater than the difference between L. vulgaris and L. forbesii, which is consistent with opportunistic behaviour in these squids. Differences in diet related to predator size do not suggest a change in trophic level during the growth of recruited stages

Reports submitted to the IWC SC in 2020 and 2022 highlighted the apparently precarious state of the Iberian porpoise due to high bycatch mortality. In the present report we provide an update with (mainly) recent information on the biology, ecology, threats and conservation status. The Committee noted that the level of bycatch of Iberian harbour porpoise (Phocoena phocoena) is considered unsustainable and will consequently cause a population-level decline. In 2022 the Committee recommended immediate actions to effectively reduce and, where possible, eliminate bycatch of harbour porpoise throughout Iberian Peninsula waters. Information published since spring 2022 includes papers on aerial surveys in Portugal, bycatch mortality estimated from strandings in Galicia (NW Spain) and Portugal, and diet. We also present some unpublished and in press material from project reports, conference presentations, the forthcoming report of the ICES Working Group on Marine Mammal Ecology (WGMME), and a review of biology, ecology, threats to, and status of, Iberian porpoise due to be published later this year. Estimates of total mortality derived from on-board observation and from strandings both suffer from limited and incomplete data, e.g. due to low onboard observer coverage, and an absence of bycatch information from strandings data for most of the northern coast of Spain, but generally suggest that annual bycatch mortality could be around 200-300 animals. Spain is developing a Recovery Plan for Iberian porpoise, which Spain considers to be “in danger of extinction”. Portugal has established a Working Group to develop the necessary Action Plan to minimize the serious threat of cetacean bycatch in fishing. The range of the population was recently designated as an Important Marine Mammal Area. It is suggested that a Working Group concerned with the ecology and conservation of this population could be formed, for example involving ASCOBANS, ACCOBAMS, ICES and the IWC

Rapana venosa (Valenciennes, 1846) is an invasive species that has spread widely around the world, which has commercial importance. For scientifically sound fishery management, accurate age determination is necessary, while the methods currently used have disadvantages. To fulfill the need for a more accurate technique, the microstructure of R. venosa statoliths collected in the northern part of the Black Sea (near the Bolshoy Utrish cape) was studied. Statoliths have well-marked concentric increments, which allows counting with sufficient accuracy. The annual periodicity of R. venosa statolith increments was cross validated using spawning marks on the shells. The growth of veined whelks was the best described by Von Bertalanffy function, with the following coefficients: L∞ = 96.19; k = 0.125; t0 = 0.043. The model accounted for 83% of variance. Moreover, the possibility to reconstruct the age of molluscs based on statolith diameter was tested. It was revealed that the number of increments versus statolith diameter relationship is exponential, the developed model described 99% of variance. Based on these data the growth of R. venosa was modelled again, resulting model accounted for 88% of variance. Coefficients of the model were: L∞ = 106.42; k = 0.102; t0 = 0.136. Potential benefits and limitations of the applied methods are discussed

1. Aquatic food systems are important contributors to global food security to satisfy an intensifying demand for protein-based diets, but global economic growth threatens marine systems. Cephalopod (octopus, squid, cuttlefish) fisheries can contribute to food security; however their sustainable exploitation requires understanding connections between nature’s contributions to people (NCP), food system policies and human wellbeing. 2. Our global literature review methodology examined what is known about cephalopod food systems, value chains and supply chains and associated market drivers. For analysis, we followed the IPBES conceptual framework to build a map of the links between cephalopod market drivers, NCP and good quality of life (GQL). Then we mapped cephalopod food system dynamics onto IPBES (in)direct drivers of change relating to catch, trade and consumption. 3. This research contributes knowledge about key factors relating to cephalopods that can support transitions towards increased food security: the value of new aquatic food species; food safety and authenticity systems; place-based innovations and empowerment of communities; and consumer behaviour, lifestyle and motivations for better health and environmental sustainability along the food value chain. We outline requirements for a sustainable, equitable cephalopod food system policy landscape that values nature’s contributions to people, considers UN Sustainable Development Goals and emphasises the role of seven overlapping IPBES (in)direct drivers of change: Economic, Governance, Sociocultural and Socio-psychological, Technological, Direct Exploitation, Natural Processes and Pollution. We present a novel market-based adaptation of the IPBES conceptual framework – our ‘cephalopod food system framework’, to represent how the cephalopod food system functions and how it can inform processes to improve sustainability and equity of the cephalopod food system. 4. This synthesised knowledge provides the basis f