Strong inference from transect sign surveys : combining spatial autocorrelation and misclassification occupancy models to quantify the detectability of a recovering carnivore

Acknowledgements We are very grateful for the input provided by Elizabeth Croose, Declan O'Mahony and Denise O'Meara on pine marten survey methodology and related constraints, which we hope this paper will go some way toward relieving. Christopher Sutherland was incredibly helpful in discussion of occupancy modelling techniques. We would also like to thank Thys Simpson, Colin McClean and Shaila Rao for arranging access to private estates for surveying. Funding — Forest Enterprise Scotland and the University of Aberdeen provided funding for the project. The Carnegie Trust supported the lead author, E. McHenry, in this research through the award of a tuition fees bursary.Peer reviewedPublisher PD

Working group on cephalopod fisheries and life history (Wgceph; outputs from 2022 meeting)

Rapports Scientifiques du CIEM. Volume 5, nº 1WGCEPH worked on six Terms of Reference. These involved reporting on the status of stocks; reviewing advances in stock identification, assessment for fisheries management and for the Ma- rine Strategy Framework Directive (MSFD), including some exploratory stock assessments; re- viewing impacts of human activities on cephalopods; developing identification guides and rec- ommendations for fishery data collection; describing the value chain and evaluating market driv- ers; and reviewing advances in research on environmental tolerance of cephalopods. ToR A is supported by an annual data call for fishery and survey data. During 2019–2021, com- pared to 1990–2020, cuttlefish remained the most important cephalopod group in terms of weight landed along the European North Atlantic coast, while loliginid squid overtook octopus as the second most important group. Short-finned squid remained the least important group in land- ings although their relative importance was almost double in 2019–2022 compared to 1992–2020. Total cephalopod landings have been fairly stable since 1992. Cuttlefish landings are towards the low end of the recent range, part of a general downward trend since 2004. Loliginid squid landings in 2019 were close to the maximum seen during the last 20 years but totals for 2020 and 2021 were lower. Annual ommastrephid squid landings are more variable than those of the other two groups and close to the maximum seen during 1992– 2021. Octopod landings have generally declined since 2002 but the amount landed in 2021 was higher than in the previous four years. Under ToR B we illustrate that the combination of genetic analysis and statolith shape analysis is a promising method to provide some stock structure information for L. forbsii. With the sum- mary of cephalopod assessments, we could illustrate that many cephalopod species could al- ready be included into the MSFD. We further provide material from two reviews in preparation, covering stock assessment methods and challenges faced for cephalopod fisheries management. Finally, we summarise trends in abundance indices, noting evidence of recent declines in cuttle- fish and some octopuses of the genus Eledone. Under ToR C, we describe progress on the reviews of (i) anthropogenic impacts on cephalopods and (ii) life history and ecology. In relation to life history, new information on Eledone cirrhosa from Portugal is included. Under ToR D we provide an update on identification guides, discuss best practice in fishery data collection in relation to maturity determination and sampling intensity for fishery monitoring. Among others, we recommend i) to include the sampling of cephalopods in any fishery that (a) targets cephalopods, (b) targets both cephalopods and demersal fishes or (c) takes cephalopods as an important bycatch, ii) Size-distribution sampling, iii) the use of standardized sampling pro- tocols, iv) an increased sampling effort in cephalopod. Work under ToR E on value chains and market drivers, in conjunction with the Cephs & Chefs INTERREG project, has resulted in two papers being submitted. Abstracts of these are in the report. Finally, progress under ToR F on environmental tolerance limits of cephalopods and climate en- velope models is discussed, noting the need to continue this work during the next cycle.info:eu-repo/semantics/publishedVersio

Long term trends in length at maturity and life history of Loligo forbesii in European waters

ICES Annual Science Conference, 9-12 September 2019, Gothenburg, SwedenCephalopods have been termed ‘weeds of the sea’ and many groups have apparently increased over recent decades. Commercially relevant cephalopods such as Loligo forbesii have increased in landings in recent years, but little is known about their vulnerability to over-fishing given their short lifecycles and status as non-quota species. Some trends in landings of this species will be presented, with an analysis of data gaps for its sustainable exploitation. Despite its commercial appeal, basic information including length-maturity data are not routinely captured for L. forbesii; however several discrete EU projects have collected this information in the last three decades. These data have been gathered by the Cephs&Chefs project and will be analysed to provide spatial and temporal trends in length-maturity as well as life-history (sex ratio) and biomass (length-weight) indices. Trends over time in this information will be examined in the context of changing ocean temperatures in the north-east AtlanticPeer reviewe

Evidence of phenotypic plasticity in Alloteuthis media (Linnaeus, 1758) from morphological analyses on North Sea specimens and DNA barcoding of the genus Alloteuthis Wülker, 1920 across its latitudinal range

Despite being landed in commercial cephalopod fisheries, species of Alloteuthis are not yet well defined, with A. subulata and A. media often confused. DNA barcoding combined with morphometric analyses has begun to clarify the distinction between these two morphologically similar species but has been limited in its geographic coverage to date. Herein, we provide DNA barcodes for 228 specimens collected from Guinea Bissau in the south, up the Atlantic coast, to the Irish shelf and North Sea. Employing species delimitation analyses, and with comparison to the literature, we identified 24 individuals of A. africana, 66 individuals of A. subulata and 138 individuals of A. media. We confirm that A. media has the northernmost distribution and is the only species identified by DNA sequencing from the Irish shelf and North Sea. We analysed morphometric measures and indices from 388 individuals from the North Sea, a subset of which (n = 58) were barcoded. The most useful traits for identification were tail length as a percentage of dorsal mantle length, and largest club sucker width as a percentage of head width. By comparison to other published data, we determined that A. media phenotypes vary substantially across the geographic range of this species. This partly explains the difficulties in morphological identification and suggests regional identification guides may be required in support of fisheries management. Interregional analyses suggest character displacement may occur where species co-exist.Open Access funding provided by the IReL Consortium. The research was supported by funding from the European Regional Development Fund through the Interreg Atlantic Area Programme (Cephs & Chefs project, grant number EAPA_282/2016).Peer reviewe

Identification of benthic egg masses and spawning grounds in commercial squid in the English Channel and Celtic Sea: Loligo vulgaris vs L. forbesii.

Common squid, Loligo vulgaris and veined squid, Loligo forbesi have nearly coinciding distribution in the northeast Atlantic, a similar reproductive seasonality, and largely overlapping depth ranges of spawning grounds. There are no unambiguous criteria to distinguish between egg masses of both species. This pioneer study was focused on Celtic Sea and western part of the English Channel and combined both research survey data and observations by recreational divers ("citizen science"). L,vulgaris was found to reproduce there in late winter – spring; distribution of egg masses coincided with bottom temperature range of 8.5-10°C and bottom salinities of 35-35.5 psu. No L.forbesii egg masses was found across the studied area though they are known from literature from deeper areas further west. Based on the original materials and literature data we provide a guideline to distinguish between egg masses of both squids based on egg size and embryonic stage as a tool to map species specific spawning grounds for improvement of understanding of population structure, migrations and development of fisheries management measures

Identification of benthic egg masses and spawning grounds in commercial squid in the English Channel and Celtic Sea: Loligo vulgaris vs L. forbesii

International audienc

Multi-method approach shows stock structure in Loligo forbesii squid

International audienceKnowledge of stock structure is a priority for effective assessment of commercially-fished cephalopods. Loligo forbesii squid are thought to migrate inshore for breeding and offshore for feeding and long-range movements are implied from past studies showing genetic homogeneity in the entire neritic population. Only offshore populations (Faroe and Rockall Bank) were considered distinct. The present study applied mitchondrial and microsatellite markers (nine loci) to samples from Rockall Bank, north Scotland, North Sea, various shelf locations in Ireland, English Channel, northern Bay of Biscay, north Spain, and Bay of Cadiz. No statistically significant genetic sub-structure was found, although some non-significant trends involving Rockall were seen using microsatellite markers. Differences in L. forbesii statolith shape were apparent at a subset of locations, with most locations showing pairwise differences and statoliths from north Ireland being highly distinct. This suggests that (i) statolith shape is highly sensitive to local conditions and (ii) L. forbesii forms distinguishable groups (based on shape statistics), maintaining these groups over sufficiently long periods for local conditions to affect the shape of the statolith. Overall evidence suggests that L. forbesii forms separable (ecological) groups over short timescales with a semi-isolated breeding group at Rockall whose distinctiveness varies over time

Spatial and temporal variability of spawning and nursery grounds of Loligo forbesii and Loligo vulgaris squids in ecoregions of Celtic Seas and Greater North Sea

International audienceThe inshore commercial squids, Loligo vulgaris and L. forbesii, co-occur in the ecoregions of Celtic Seas and Greater North Sea but the spatio-temporal structure of their spawning ranges is poorly understood. To help solve the problem, data sets collected during the last 30 years by British, German, French, and Irish scientists, as well as observations from multinational Citizen Science, were combined. Spawning grounds of L. forbesii were found to form an external semi-circle around the spawning grounds of L. vulgaris, with the latter being centred on the English Channel and southernmost North Sea. The nursery grounds of both species appear to coincide with the respective spawning grounds, though L. forbesii makes much wider use of the North Sea. Seasonally, the position of the spawning grounds of both species is driven by the local temperature regime, although this is possibly subject to interannual variability. Spawning of both species begins around November and gradually progresses eastward following favourable currents and increasing water temperatures. Spawning in both species is mostly over by July, though some egg masses persist until August–November. Nursery grounds follow the same seasonal shift from west to east, at least in L. forbesii