Spatial and temporal dynamics of common cuttlefish, Sepia officinalis, spawning at north European shores was studied using data collected by the Cephalopod Citizen Science Project, Seasearch between 1995 and 2021 and a range of other internet sources for the same period. Reproduction begins in the western English Channel in March and gradually progresses eastward following water warming, attaining the Netherlands in May, when peripheral spawning grounds expand north to Norfolk and the Irish Sea. Despite a thermal regime favourable for egg development existing around the UK and Ireland, spawning is normally restricted to the English Channel and southernmost North Sea with egg masses occasionally observed as far north as Isle of Man and Norfolk.

There is ever-greater need for information about changing marine biodiversity, but such information is sparse at large spatial or temporal scales. Records about distributions of species collected by volunteers can fill gaps in knowledge that cannot yet be addressed by more structured sampling. Bayesian occupancy models show great promise for estimating trends in occurrence of species through time. This study uses the Sparta occupancy model with records from the Seasearch programme from coastal waters of Britain and Ireland during the period 2000–2020, focussing on three species of Crustacea (Cancer pagurus, Homarus gammarus and Palinurus elephas). Populations of P. elephas crashed in the 1970s, but now appear to be re-establishing in south-west England. The Sparta model provides evidence about recovery that is more robust than anecdotal reports or simple counts of records. Estimates of occupancy are made at different spatial scales and compared among species and areas. Trends in occupancy are compared qualitatively with patterns in fisheries landings data. Occupancy by P. elephas has increased drastically since 2014, a pattern not seen in the other two species. For each species, occupancy varied among areas and in some areas, patterns in estimates of occupancy were similar to trends in landings from fisheries. Citizen science records are increasingly recognized to have value which has not yet been fully exploited. Greater use should be made of the Seasearch dataset in order to provide population trends for benthic marine taxa. Such analyses will broaden our understanding of and taxonomic coverage of changes in biodiversity.

The European hedgehog, Erinaceus europaeus, is frequently admitted to rescue centres in the UK. With many overwintering in captivity, there is cause to investigate hibernation patterns in order to inform and improve husbandry and monitoring protocols. Thirty-five hedgehogs were studied over two winters. Weight change during hibernation for the first winter was used to test for effects of disturbance on different aspects of hibernation, including total duration, frequency and duration of spontaneous arousals. There was no significant difference between the two winters for any of the four aspects studied. Significant positive correlations demonstrated that weight-loss increased with the duration of the hibernation period and with percent of nights spent asleep, but not with the number of arousal events. Thus, weight-loss appears more strongly associated with the proportion of time spent asleep than with the number of arousal events. This was surprising given the assumed energetic expense of repeated arousal and was potentially due to availability of food during arousals. In contrast with previous studies, larger hedgehogs lost less weight per day than did smaller hedgehogs. They also woke up more often (i.e., had more opportunities to feed), which may explain the unexpected pattern of weight-loss. Hibernatory behaviour in captivity differs from that in the wild, likely because of non-natural conditions in hutches and the immediate availability of food. This study provides a basis for further research into the monitoring and husbandry of hedgehogs such that it can be adapted for each individual according to pre-hibernation weight and behaviour during hibernation.

The European hedgehog (Erinaceus europaeus) is the most common mammal species admitted to rescue centres in the UK. The temperature of a new admission is useful in assessing health status, hypothermia can indicate shock or impaired health, assessing this can be challenging due to their ability to curl tightly. Measuring body temperature using conventional rectal thermometers is not possible. In order to improve welfare and to maximise successful rehabilitation, it is important to incorporate new technology and understanding into husbandry, assessment and diagnostic protocols and practices used within these rescue centres. This study assessed and diagnosed hypothermia, a common condition of new arrivals as a result of shock, using corneal temperature as recorded by a FLIR E60bx infrared camera, at Prickles and Paws Hedgehog Rescue Centre, Cubert, Cornwall. Corneal temperatures were recorded ranging from 14.3 to 37.4 °C. The thermal camera provided greater accuracy over observational diagnosis made by rescue centre staff, with a significant difference between diagnostic categories, demonstrating misdiagnosis by observation alone of 42% of individuals.. There was a higher mortality within those diagnosed by IRT to be 'mildly hypothermic' or 'hypothermic', with death occurring within 72 h of diagnosis. These findings provide a basis for further research into the treatment of hypothermia in E. europaeus now that temperature can be more accurately assessed by non-invasive methods.

Jennifer Dannheim *, Lena Bergström, Silvana N. R. Birchenough, Radosław Brzana, Arjen R. Boon, Joop W. P. Coolen , Jean-Claude Dauvin, Ilse De Mesel, Jozefien Derweduwen, Andrew B. Gill, Zoë L. Hutchison, Angus C. Jackson, Urszula Janas, Georg Martin, Aurore Raoux, Jan Reubens, Liis Rostin, Jan Vanaverbeke, Thomas A. Wilding, Dan Wilhelmsson, and Steven Degraer Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Science, Am Handelshafen 12, Bremerhaven 27570, Germany Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, Oldenburg 26129, Germany Department of Aquatic Resources, Swedish University of Agricultural Sciences, Skolgatan 6, Öregrund 74242, Sweden Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK Institute of Oceanography, University of Gdansk, Al. Marsz. J. Pilsudskiego 46, Gdynia 81-378, Poland Deltares, Unit Marine and Coastal Studies, P.O. Box 177, Delft 2600 MH, The Netherlands Wageningen Marine Research (Formerly IMARES), P.O. Box 57, Den Helder 1780 AB, The Netherlands Aquatic Ecology and Water Quality Management Group, Wageningen University, Droevendaalsesteeg 3a, Wageningen 6708 PD, The Netherlands Normandie Univ, UNICAEN, Laboratoire Morphodynamique Continentale et Côtière, CNRS, UMR 6143 M2C, 24 Rue des Tilleuls, Caen 14000, France Operational Directorate Natural Environment (OD Nature), Marine Ecology and Management (MARECO), Royal Belgian Institute of Natural Sciences, Vautierstraat 29, Brussels B-1000, Belgium Institute for Agricultural and Fisheries Research (ILVO), Ankerstraat 1, Oostende B-8400, Belgium PANGALIA Environmental, Ampthill, Bedfordshire, UK Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA Centre of Applied Zoology, Cornwall College Newquay, Wildflower Lane, Trenance Gardens, Newquay, Cornwall TR7 2LZ, UK Estonian Marine Institute, University of Tartu, Mäealuse 14, Tallinn 12618, Estonia Flanders Marine Institute, Wandelaarkaai 7, Oostende 8400, Belgium Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, UK Swedish Secretariat for Environmental Earth System Science (SSEESS), Royal Swedish Academy of Science, Box 50005, Stockholm 104 05, Sweden *Corresponding author: tel: þ 49 471 4831 1734; e-mail: jennifer.dannheim@awi.de.

Increasing use of the marine environment and changes in weather extremes from climate change are altering patterns of sediment deposition on benthic habitats. There is a need to understand behavioural responses to such stressors, especially in sessile species that are of conservation, ecological or commercial interest. We investigated how two biogenic reef-forming, epifaunal mussels, Modiolus modiolus (horse mussel) and Mytilus edulis (blue mussel) responded to gradual burial by sediment. Here we used experiments to assess behavioural strategies for surviving modest, but regular sediment deposition regimes (0.5, 1.0 or 1.5 cm d(-1) of coarse, medium-fine or fine sediment for 2, 4, 8 or 16 days), that result in gradual burial. M. modiolus was only capable of maintaining contact with the sediment-water interface during slow rates of deposition for short durations (tested in fine sediment only). M. edulis, however, were capable of vertical migration through sediment in all experimental sedimentation rates, sediment fractions and durations, but the frequency of burial increased with increasing sedimentation rate and duration. In this study, the sediment fraction was not influential on the levels of burial observed in M. edulis. Inter-individual variation in the ability of M. edulis to vertically migrate was investigated to understand sub-lethal effects of exposure to sedimentation. In M. edulis a molecular approach was used to assess variation in the condition and protein turnover in tissues with different functional roles (gill, adductor and foot tissue). Concentrations of RNA in the muscular foot were positively associated with the frequency of burial and the total depth of burial, indicating that burial stimulates protein production, most likely associated with byssus production used in the burial escape response. These findings contribute to a better understanding of how mussels respond to, and survive gradual burial by sediment and provide insight into how ongoing changes in sediment dynamics may influence these ecologically and commercially important reef-building species. These findings can be used to assist in managing activities which may result in sedimentation around these important species.

As the EU's commitment to renewable energy is projected to grow to 20% of energy generation by 2020, the use of marine renewable energy from wind, wave and tidal resources is increasing. This literature review (233 studies) (i) summarizes knowledge on how marine renewable energy devices affect benthic environments, (ii) explains how these effects could alter ecosystem processes that support major ecosystem services and (iii) provides an approach to determine urgent research needs. Conceptual diagrams were set up to structure hypothesized cause-effect relationships (i.e. paths). Paths were scored for (i) temporal and spatial scale of the effect, (ii) benthic sensitivity to these effects, (iii) the effect consistency and iv) scoring confidence, and consecutively ranked. This approach identified prominent knowledge gaps and research needs about (a) hydrodynamic changes possibly resulting in altered primary production with potential consequences for filter feeders, (b) the introduction and range expansion of non-native species (through stepping stone effects) and, (c) noise and vibration effects on benthic organisms. Our results further provide evidence that benthic sensitivity to offshore renewable effects is higher than previously indicated. Knowledge on changes of ecological functioning through cascading effects is limited and requires distinct hypothesis-driven research combined with integrative ecological modelling.

Increasing concentrations of atmospheric carbon dioxide are causing oceanic pH to decline worldwide, a phenomenon termed ocean acidification. Mounting experimental evidence indicates that near-future levels of CO2 will affect calcareous invertebrates such as corals, molluscs and gastropods, by reducing their scope for calcification. Despite extensive research into ocean acidification in recent years, the effects on non-calcifying anthozoans, such as sea anemones, remain little explored. In Western Europe, intertidal anemones such as Actinia equina are abundant, lower trophic-level organisms that function as important ecosystem engineers. Changes to behaviours of these simple predators could have implications for intertidal assemblages. This investigation identified the effects of reduced seawater pH on feeding and contest behaviour by A. equina. Video footage was recorded for A. equina feeding at current-day seawater (pH 8.1), and the least (pH 7.9) and most (pH 7.6) severe end-of-century predictions. Footage was also taken of contests over ownership of space between anemones exposed to reduced pH and those that were not. No statistically significant differences were identified in feeding duration or various aspects of contest behaviour including initiating, winning, inflating acrorhagi, inflicting acrorhagial peels and contest duration. Multivariate analyses showed no effect of pH on a combination of these variables. This provides contrast with other studies where anemones with symbiotic algae thrive in areas of natural increased acidity. Thus, novel experiments using intraspecific contests and resource-holding potential may prove an effective approach to understand sub-lethal consequences of ocean acidification for A. equina, other sea anemones and more broadly for marine ecosystems.

Offshore marine renewables energy developments (MREDs), particularly in the light of extensive offshore wind farm development in shallow shelf seas, are expected to affect the structure and functioning of marine ecosystems. Several activities linked to the installation and operation of MREDs each have their differential impacts onto the ecosystem. The benthos plays key roles in the ecosystem, supporting numerous ecosystem goods and services such as long-term carbon storage and food resources for higher trophic groups (e.g. fish, birds, mammals and including humans). Development of MREDs will initiate processes which are expected to affect benthic assemblages over various, currently unknown, spatial and temporal scales. This work provides a structured overview of ecological cause-effect relationships related to MREDs, based on a set of hypothesis-driven pathways supported by literature (>230 publications reviewed). Furthermore, this work evaluated the sensitivity of benthic causeeffect relationships to potential effects of MREDs on different spatial and temporal scales and weighted the assessment by confidence in existing knowledge and the consistency of effects among habitats. The outcomes allowed identification of knowledge gaps about ecological processes, in order to prioritize the ‘known-unknowns’ and highlight priority research areas. Our results suggest that the sensitivity of the benthos to MREDs is much higher than previously indicated, particularly where cascading effects lead to changes in ecological functioning. Filling existing knowledge gaps and understanding ecological processes and patterns occurring at low-trophic levels, including those within the benthos, are essential to maintain ecological integrity key to the ecosystem and to society even under MREDs developments.

The global increase in tidal stream turbine installations creates a need to identify and mitigate any impacts on seabird populations. Within Scotland, UK, the vulnerability of black guillemots Cepphus grylle and European shags Phalacrocorax aristotelis is dependent on their tendency to exploit microhabitats characterised by fast mean horizontal current speeds (≥2ms–1), and tidal states with maximum current speeds, within tidal stream environments. Identifying consistencies in their relative use of different microhabitats (fast versus slow mean horizontal current speeds) and tidal states (increasing/decreasing versus maximum currents) across these habitats could assist risk assessment and mitigation measures at both a regional and development site level. Datasets from shore-based surveys collated across 6 tidal stream environments showed that the probability of detecting foraging black guillemots and European shags tended to be higher in fast and slow microhabitats, respectively. However, differences between microhabitats were reversed and/or marginal in 3 out of the 5 sites used for each species. Differences between tidal states were almost always marginal. These variabilities show that a species' vulnerability could differ greatly among development sites, and environmental impact assessments (EIA) must quantify habitat-use using dedicated and site-specific surveys to reduce uncertainty. However, a greater understanding of the mechanisms underlying variation in the use of tidal stream environments is needed when selecting a suite of potential development sites that reduce the possibility of population-level impacts. The current collection of physical and biological data across tidal stream environments could therefore prove invaluable for the protection of seabird populations.

Growing concerns about climate change and energy security have fuelled a rapid increase in the development of offshore and marine renewable energy installations (OMREIs). The potential ecological consequences of increased use of these devices emphasises the need for high quality environmental impact assessment (EIA). We demonstrate that these processes are hampered severely, primarily because legislation does not ensure that the significance of impacts and cumulative effects are properly assessed. We highlight why the regulatory framework leads to conceptual ambiguities and propose changes which, for the most part, do not require major adjustments to standard practice. We emphasise the importance of determining the degree of confidence in impacts to permit the likelihood as well as magnitude of impacts to be quantified and propose ways in which assessment of population-level impacts could be incorporated into the EIA process. Overall, however, we argue that, instead of trying to ascertain which particular developments are responsible for tipping an already heavily degraded marine environment into an undesirable state, emphasis should be placed on better strategic assessment.

Atlantic salmon (Salmo salar) are iconic and economically important fish, but their migratory behaviour during passage through Scottish coastal seas is not well understood, and there are several key questions which need to be answered in order to predict possible interactions with marine renewable energy arrays. Do migrating salmon (adults and post-smolts) travel through marine renewable energy development areas? Will migrating fish actually encounter arrays of devices as they pass through these areas? What effects might these encounters have on migrating salmon, and what might be the consequences of these interactions for fish populations? In response to these questions, the Environmental Research Institute has established the Pentland Salmon Initiative - a new partnership which aims to engage a growing number of organisations with interests or experience relevant to marine renewables and salmon migration, with a particular focus on the Pentland Firth. This site represents not only a potential bottleneck for migrating salmon but also a key site for the developing marine energy sector. We are actively seeking to build and extend collaborative programmes under four broad themes, which are outlined below.

Seabirds are important marine predators that may be influenced by developments in marine renewable energy. To explore how seabirds might exploit novel floating structures at sea, an autonomous camera system was used to record attendance of seabirds on a Pelamis wave-energy device. Numbers and identities of seabirds on the machine were explored in relation to a set of metocean variables. Use of the machine was most affected by time of day, but less so by state of the tide. Birds did not use the machine during strong winds or when waves were large. Cameras can provide an effective, low-cost way to collect data about seabirds over weeks or months in inaccessible locations and under inclement metocean conditions.

Capsule Black Guillemots Cepphus grylle were recorded diving in the Pentland Firth to an average depth of 32 metres and an overall maximal depth of 43 metres. The majority (88%) of dives were benthic with a median dive duration of 95 seconds, and a maximal dive duration of 131 seconds. The results provide empirical evidence that Black Guillemots use depths within the water column at which tidal turbines are likely to operate. Although limited, our data suggest the potential for interactions between Black Guillemots and marine renewable energy devices.