Knowledge on the distribution of zooplankton in the many unique habitats of the Southern Ocean is essential for understanding food web dynamics, assessing the impacts of environmental change and for managing the exploitation of marine living resources. Variation in the distribution of zooplankton may occur in the horizontal as well as the vertical plane, and the latter may show a diel cycle (diel vertical migration or DVM). Conventional sampling methods, including several types of nets and acoustics, often undersample or ignore the top 10 m of the water column. The surface waters may, however, host a specific zooplankton community and therefore be an important foraging ground for higher trophic level predators. In order to investigate the importance of the surface waters for understanding the distribution of species and potentially improving abundance estimates, the upper two meters of the water column were sampled in the eastern Indian sector of the Southern Ocean using a Surface and Under Ice Trawl (SUIT). Findings were compared to the zooplankton community structure in the epipelagic (15-200 m). Results showed that the surface zooplankton community could largely be divided into two regions. The surface community of the western side of the sampling area hosted large numbers of Antarctic krill, Euphausia superba, which were only present in low densities in the epipelagic depth layer. Densities of Limacina helicina were also relatively high in the west. The copepod Calanus propinquus and the amphipod Themisto gaudichaudii were present in relatively large numbers throughout the sampling area. T. gaudichaudii was the dominant species of the surface in the eastern side of the sampling area in the absence of Antarctic krill. Apart from cirripedia nauplii, no species were uniquely found in the surface water compared to the 15-200 m depth layer. Surface water sampling revealed patterns in vertical distribution and DVM, and showed that these patterns changed between the first and second half of the expedition. This could partially be explained by environmental variables but was likely also a result of sampling time and location, and associated variation in the size and ontogeny of species. Results revealed the impact of undersampling the surface layer regarding knowledge on distribution and vertical migration patterns of zooplankton species.

Arnoux's beaked whales (Berardius arnuxii) are generally considered to be uncommon to rare, and likely to prefer deep oceanic waters of the Southern Hemisphere. During many top-predator surveys in the Southern Ocean since 1988 we did not sight the species. However, in April 2022 we encountered three groups in the marginal sea-ice zone of the Weddell Sea. This study provides detailed descriptions of the sighted animals and their environment and report on unpublished sightings of this species from 1986 to 1998. A search of published information on the distribution of the species revealed 108 documented sightings with a total of 1,125 individuals. In combination these sources of information for the Southern Ocean, suggest a frequent occurrence in ice-covered waters, often close to the continental coast and edges of fast ice and ice-shelves. North of 60 degrees S, in the temperate regions of the Southern Hemisphere, the species was also regularly sighted near continents, even far inshore, in fjords surrounded by land.

Stomach contents of dead birds beached along the Dutch Wadden Sea and North Sea coast during 2019 were investigated for the potential presence of plastics lost from containers in the MSC Zoe incident, 1 to 2 January 2019. The focus was on the detection of industrial polyethylene (PE) pellets and Polystyrene (PS) microbeads as were spilled during the incident. For northern fulmars reference material from earlier years was available. Looking at the presence of PE pellets and PS beads in 2019 in comparison to earlier years there was no direct effect of the container incident. For some species no adequate reference data were available, however, no plastics similar to those lost during the incident were found.

Seabird bycatch is common in longline fisheries and detrimental to some seabird populations. Simultaneously, the loss of longline bait to seabirds may pose a considerable economic loss to fishermen. Here, we study northern fulmars (Fulmarus glacialis), bycaught in longline fisheries close to the Faroe Islands between 2004 and 2021. Biological data on age and sex and the quantity of bait in the stomachs was assessed. Males were over-represented in the bycatch sample, as were adult birds, likely caused by sex- and age-specific foraging segregation. Overall, 71% of 820 fulmars contained bait, on average 2 items per bird (range: 0-17 items). No difference in the average number of bait items was detected between males and females or between adult and non-adult birds. During the breeding season, however, adults contained significantly more bait in their stomach than outside the breeding season. No such effect was found for non-adult birds. Together with a lower body condition during the breeding season, this may indicate higher food requirements by breeding birds, potentially increasing entanglement risks. Regular loss of bait reduces fishing efficiency, likely resulting in economic loss. Reducing seabird bycatch may therefore benefit fishermen as well as seabird populations.

Antarctic krill (Euphausia superba) is a harvested species that has an important role in the Southern Ocean food web. Knowledge on the demography of Antarctic krill is necessary for a better understanding of the distribution of life stages and their relation with predator species. In addition, such information is essential for krill fisheries management by CCAMLR (Commission on the Conservation of Antarctic Marine Living Resources). A large part of the Indian sector of the Southern Ocean is understudied and large-scale krill surveys of this region are scarce. Therefore, a survey was carried out during the austral summer of 2018/2019 on board RV Kaiyo-maru in the region from 80 to 150˚E. Krill was collected using a Rectangular Midwater Trawl (RMT). Previous studies suggest that part of the Antarctic krill population resides in the upper surface of the water column, but traditional trawls and echosounders have not been able to fully investigate this stratum due to sampling constraints. To overcome this knowledge gap, the upper surface (0-2 m) was sampled using a Surface and Under Ice Trawl (SUIT) in addition to the standard survey net. Results show that there were differences in the horizontal and vertical distribution of post-larval krill between the area west and east of approximately 120˚E. These differences coincided with variation in environmental properties. Early calyptopis larvae were found throughout the survey area. Their relatively low numbers suggested ongoing spawning that started early in the season. Juveniles were found mainly in the western side of the sampling area and large densities of this developmental stage were found to reside in the upper two meters of the water column. The quantitative estimation of krill in the upper surface indicated that undersampling this part of the population may influence estimates of, for example, recruitment.

This document is an illustrated report intended for the surveyors in the monitoring program of plastic particles from stomachs of beached Northern Fulmars (Fulmarus glacialis). It contains brief summary information and photos of stomach contents from individual birds. The previous report contained only some of birds collected in 2020 because of corona travel restrictions. The current report therefore shows all birds from the UK for 2020 and 2021 (plus a late 2018 bird from Shetland). Low sample sizes are not a problem for the monitoring program although larger sample sizes will increase the potential for statistical analyses. In order to avoid the variability in annual samples, the ‘current situation’ is viewed as an average over the most recent five consecutive years. During 2017-2021, 84% of 108 fulmar stomachs from the UK North Sea coasts contained plastic with an average per bird of 24 particles and 0.17 g in mass. The Fulmar-Threshold-Value (FTV) of 0.1 g was exceeded by 45% of the stomachs. The international policy aim is that this percentage should be reduced to below 10%. For details on e.g. trends, see the 2021 update of the scientific monitoring report series for the UK.

This is an illustrated report on the 76 Northern Fulmars investigated in the Netherlands in 2022 for the monitoring program of plastic particles in their stomachs. An additional seven late delivered corpses of fulmars were investigated. This research is part of the international program that measures progress towards the so-called ‘Good Environmental Status (GES)’ in European marine waters. Full study results will be published in a formal research report.

This document is an illustrated report for the surveyors in the monitoring program of plastics particles in stomachs of beached Northern Fulmars (Fulmarus glacialis). It contains short information and photos of stomach contents of individual birds. In 2020 nine corpses were collected, one of which contained no stomach due to scavenging. Occasional years of lower sample size are not a problem for the monitoring program although larger samples will increase potential for statistical analyses. Averaged values are looked at in the larger samples over 5 consecutive years. Over the 2016-2020 period, 98 stomachs of fulmars from the UK contained an average per bird of 23 particles and 0.16 g of plastic.

Dit is een geïllustreerd rapport over de 81 Noordse Stormvogels die in 2021 in Nederland werden onderzocht in het kader van het monitoring programma van plastics in hun magen.Zulk onderzoek maakt deel uit van het internationale programma dat metingen verricht aan de voortgang naar de zogenoemde 'Goede Milieu Toestand (GMT)' in de Europese zeegebieden.Volledige studieresultaten worden in jaarlijkse formele onderzoekrapporten gepubliceerd.This is an illustrated report on the 81 Northern Fulmars investigated in the Netherlands in 2021 for the monitoring program of plastic particles in their stomachs.This research is part of the international program that measures progress towards the so-called 'Good Environmental Status (GES)' in European marine waters.Full study results will be published in a formal research report.

Fulmar Litter Threshold monitoring in the Netherlands -Update 2021Marine debris has serious economic and ecological consequences.Economic impacts are most severe for coastal communities, tourism, shipping and fisheries.Marine wildlife suffers from entanglement and ingestion of debris, with micro-particles potentially affecting marine food chains up to the level of human consumers.In the North Sea, marine litter problems were firmly recognized in 2002 when surrounding states assigned to OSPAR the task to include marine plastic litter in its system of Ecological Quality Objectives (EcoQOs) (North Sea Ministerial Conference 2002).At that time, in the Netherlands, marine litter was already monitored by the abundance of plastic debris in stomachs of a seabird species, the Northern Fulmar (Fulmarus glacialis).In 2020 the fulmar EcoQO was formally replaced and is now called Fulmar Threshold Value (Fulmar-TV or FTV; for more details see Van Franeker et al. 2021 and Kühn et al. 2021a).7.Over the 5-year period 2017-2021, 24% of the birds had ingested paraffin-like substances, with an average mass of 1.8 gram per bird. CONCLUSIONOn the longer term, stomach contents of fulmars beached in the Netherlands indicate that the marine litter situation off the Dutch coast is gradually improving, but still far off the Fulmar Threshold Value.At the current rate of the trend, the Fulmar-TV might be reached around the year 2066.Within 10-year evaluation periods the trend is not consistent, and showed no significant change over the most recent 2012-2021 decade.Future data must reveal if this reflects a temporary deviation, or a reversal in the longer term trend.

A sample of 145 stomachs from fulmars hunted 100 km offshore east Greenland 64° 30′ N in early June 2015 was analysed for abundance of plastic litter. Overall, 86% of the stomachs contained plastics with an average of 13.5 particles, and 0.14 g per stomach. A proportion of 42% of the stomachs exceeded the level of 0.1 g plastic, whereas the international policy target aims at a reduction to less than 10%. The observed quantity of ingested plastic fits a pattern of reduced plastic abundance at higher latitudes, at greater distance from densely populated and industrialised areas. A subsample of 20 fulmars of known age and sex indicated that young birds contained more plastic than adults, and females more than males. Indirect evidence from age and sex composition in the full sample supported these findings. Further confirmation was found in literature and by re-analysis of earlier datasets. Differences in colony attendance could explain the combined effects of age, sex, and possibly season on plastic abundance in the stomachs. With a consistent monitoring sampling regime, such variations do not impair the results, but for evaluation of regional patterns from incidental observations or the planning of new monitoring schemes they are important.

Allometric relationships between body properties of animals are useful for a wide variety of purposes, such as estimation of biomass, growth, population structure, bioenergetic modelling and carbon flux studies. This study summarizes allometric relationships of zooplankton and nekton species that play major roles in polar marine food webs. Measurements were performed on 639 individuals of 15 species sampled during three expeditions in the Southern Ocean (winter and summer) and 2374 individuals of 14 species sampled during three expeditions in the Arctic Ocean (spring and summer). The information provided by this study fills current knowledge gaps on relationships between length and wet/dry mass of understudied animals, such as various gelatinous zooplankton, and of animals from understudied seasons and maturity stages, for example, for the krill Thysanoessa macrura and larval Euphausia superba caught in winter. Comparisons show that there is intra-specific variation in length–mass relationships of several species depending on season, e.g. for the amphipod Themisto libellula. To investigate the potential use of generalized regression models, comparisons between sexes, maturity stages or age classes were performed and are discussed, such as for the several krill species and T. libellula. Regression model comparisons on age classes of the fish E. antarctica were inconclusive about their general use. Other allometric measurements performed on carapaces, eyes, heads, telsons, tails and otoliths provided models that proved to be useful for estimating length or mass in, e.g. diet studies. In some cases, the suitability of these models may depend on species or developmental stages.

Because annual data may show strong variation due to smaller sample size or other reasons, the fulmar monitoring program mostly considers data over 5 year periods. For the United Kingdom, over the 5 year period 2016-20, 85% of 98 investigated fulmars had some plastic in the stomach. Averaged over all individuals, stomachs contained 22.7 plastic particles, mostly small, with a combined average mass of 0.16 gram per bird. The major figure to consider in terms of national and international policy, is that of the EcoQ Performance (EcoQ%), the percentage of birds exceeding the level of 0.1 gram plastic in the stomach. OSPAR has formulated a long term policy target for ecological quality in relation to plastic marine litter, which states that the percentage of fulmars with more than 0.1 g of plastic in the stomach must be reduced to under 10% for at least five consecutive years.

Survival of larval Antarctic krill ( Euphausia superba ) during winter is largely dependent upon the presence of sea ice as it provides an important source of food and shelter. We hypothesized that sea ice provides additional benefits because it hosts fewer competitors and provides reduced predation risk for krill larvae than the water column. To test our hypothesis, zooplankton were sampled in the Weddell-Scotia Confluence Zone at the ice-water interface (0–2 m) and in the water column (0–500 m) during August–October 2013. Grazing by mesozooplankton, expressed as a percentage of the phytoplankton standing stock, was higher in the water column (1.97 ± 1.84%) than at the ice-water interface (0.08 ± 0.09%), due to a high abundance of pelagic copepods. Predation risk by carnivorous macrozooplankton, expressed as a percentage of the mesozooplankton standing stock, was significantly lower at the ice-water interface (0.83 ± 0.57%; main predators amphipods, siphonophores and ctenophores) than in the water column (4.72 ± 5.85%; main predators chaetognaths and medusae). These results emphasize the important role of sea ice as a suitable winter habitat for larval krill with fewer competitors and lower predation risk. These benefits should be taken into account when considering the response of Antarctic krill to projected declines in sea ice. Whether reduced sea-ice algal production may be compensated for by increased water column production remains unclear, but the shelter provided by sea ice would be significantly reduced or disappear, thus increasing the predation risk on krill larvae.

Monitoring plastic in stomachs of beached northern fulmars for OSPAR?s Ecological Quality Objectives (EcoQOs) has been incorporated into the European Marine Strategy Framework Directive (MSFD). This paper aims to provide the appropriate tools to interpret the monitoring results. MSFD requires a data-derived threshold value (Fulmar-TV) representing ?Good Environmental Status?. Such Fulmar-TV was calculated from near-pristine Canadian Arctic data where 10.06% of fulmars exceeded the level of 0.1 g ingested plastic. This Fulmar-TV is almost identical to the earlier OSPAR EcoQO, arbitrarily set at 10%. The MSFD approach was evaluated for 2661 North Sea fulmars in 2002?2018. Between 2014 and 2018, 51% of 393 fulmars exceeded 0.1 g plastic, significantly above the proposed Fulmar-TV. Linear regression of individual ingested plastic mass over the 2009?2018 period indicates a significant decrease. Over the longer term 2002?2018, logistic regression of annual EcoQ% shows a significant decline and predicts compliance with the Fulmar-TV by 2054.

A rigorous synthesis of the sea-ice ecosystem and linked ecosystem services highlights that the sea-ice ecosystem supports all 4 ecosystem service categories, that sea-ice ecosystems meet the criteria for ecologically or biologically significant marine areas, that global emissions driving climate change are directly linked to the demise of sea-ice ecosystems and its ecosystem services, and that the sea-ice ecosystem deserves specific attention in the evaluation of marine protected area planning. The synthesis outlines (1) supporting services, provided in form of habitat, including feeding grounds and nurseries for microbes, meiofauna, fish, birds and mammals (particularly the key species Arctic cod, Boreogadus saida, and Antarctic krill, Euphausia superba, which are tightly linked to the sea-ice ecosystem and transfer carbon from sea-ice primary producers to higher trophic level fish, mammal species and humans); (2) provisioning services through harvesting and medicinal and genetic resources; (3) cultural services through Indigenous and local knowledge systems, cultural identity and spirituality, and via cultural activities, tourism and research; (4) (climate) regulating services through light regulation, the production of biogenic aerosols, halogen oxidation and the release or uptake of greenhouse gases, for example, carbon dioxide. The ongoing changes in the polar regions have strong impacts on sea-ice ecosystems and associated ecosystem services. While the response of sea-ice–associated primary production to environmental change is regionally variable, the effect on ice-associated mammals and birds is predominantly negative, subsequently impacting human harvesting and cultural services in both polar regions. Conservation can help protect some species and functions. However, the key mitigation measure that can slow the transition to a strictly seasonal ice cover in the Arctic Ocean, reduce the overall loss of sea-ice habitats from the ocean, and thus preserve the unique ecosystem services provided by sea ice and their contributions to human well-being is a reduction in carbon emissions.