Arctic Marine Data Collection Using Oceanic Gliders: Providing Ecological Context to Cetacean Vocalizations

To achieve effective management and understanding of risks associated with increasing anthropogenic pressures in the ocean, it is essential to successfully and efficiently collect data with high spatio–temporal resolution and coverage. Autonomous Underwater Vehicles (AUVs) are an example of technological advances with potential to provide improved information on ocean processes. We demonstrate the capabilities of a low-power AUV buoyancy glider for performing long endurance biological and environmental data acquisition in Northern Norway. We deployed a passive acoustic sensor system onboard a SeagliderTM to investigate presence and distribution of cetaceans while concurrently using additional onboard sensors for recording environmental features (temperature, salinity, pressure, dissolved oxygen, and chlorophyll a). The hydrophone recorded over 108.6 h of acoustic data during the spring months of March and April across the continental shelf break and detected both baleen and odontocete species. We observed a change in cetacean detections throughout the survey period, with humpback whale calls dominating the soundscape in the first weeks of deployment, coinciding with the migration toward their breeding grounds. From mid-April, sperm whales and delphinids were the predominant species, which coincided with increasing chlorophyll a fluorescence values associated with the spring phytoplankton blooms. Finally, we report daily variations in background noise associated with fishing activities and traffic in the nearby East Atlantic shipping route. Our results show that gliders provide excellent platforms for collecting information about ecosystems with minimal disturbance to animals, allowing systematic observations of our ocean biodiversity and ecosystem dynamics in response to natural variations and industrial activities.publishedVersio

Nutrient concentrations in minke whale faeces and the potential impact on dissolved nutrient pools off Svalbard, Norway

There is increasing interest in assessing the impact of whales on nutrient and carbon cycling in the ocean. By fertilising surface waters with nutrient-rich faeces, whales may stimulate primary production and thus carbon uptake, but robust assessments of such effects are lacking. Based on the analysis of faeces collected from minke whales (n = 31) off Svalbard, Norway, this study quantified the concentration of macro and micronutrients in whale faeces prior to their release in seawater. Concentrations of the macronutrients nitrogen (N) and phosphorous (P) in minke whale faeces were 50.1 ± 10.3 and 70.9 ± 12.1 g kg−1 dry weight, respectively, while the most important micronutrients were zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu). By combining measured faecal nutrient concentrations with estimated prey-consumption and prey-assimilation rates, we calculate that the current population of approximately 15, 000 individuals in the small management area (SMA) of Svalbard defecates daily 7 ± 1.4 tonnes (t) N and 10 ± 1.7 t P during summer. The molar ratio of N:P in minke whale faeces was 1.6:1, meaning that N was proportionally limiting, when compared to average elemental ratios of 16:1 in phytoplankton. In case of no N limitation in surface waters at that time, the release of elemental P through defecation in surface waters has the potential to stimulate 407 ± 70 t of carbon per day during summer as new or regenerated primary production in the SMA of Svalbard. This amounts to 0.2 to 4 % of daily net primary production in this region. This study provides the first assessment of nutrient concentration in whale faeces prior to their dissolution in sea water. Further research, namely on the amount of N released via urine and seasonal changes in excreted nutrients, is needed to better assess the full potential of whale nutrient additions to dissolved nutrient pools in surface waters at regional and global scales.publishedVersio

Using an omnidirectional video logger to observe the underwater life of marine animals : humpback whale resting behaviour

This study was supported by the Bio-Logging Science of the University of Tokyo (UTBLS) program, the Japan Society for the Promotion of Science Postdoctoral Fellowships Research Abroad, the Japan Society for the Promotion of Science (grant number 17H00776 K.S), the Japan Society for the Promotion of Science Bilateral Open Partnership Joint Research Program, the Mitsui and Co. Environment Fund, and The Research Grant against Global Warming of the Ichimura Foundation for New Technology.Animal-borne video loggers are powerful tools for investigating animal behaviour because they directly record immediate and extended peripheral animal activities; however, typical video loggers capture only a limited area on one side of an animal being monitored owing to their narrow field of view. Here, we investigated the resting behaviour of humpback whales using an animal-borne omnidirectional video camera combined with a behavioural data logger. In the video logger footage, two non-tagged resting individuals, which did not spread their flippers or move their flukes, were observed above a tagged animal, representing an apparent bout of group resting. During the video logger recording, the swim speed was relatively slow (0.75 m s ), and the tagged animal made only a few strokes of very low amplitude during drift diving. We report the drift dives as resting behaviour specific to baleen whales as same as seals, sperm whales and loggerhead turtles. Overall, our study shows that an omnidirectional video logger is a valuable tool for interpreting animal ecology with improved accuracy owing to its ability to record a wide field of view.Publisher PDFPeer reviewe

Non-lunge feeding behaviour of humpback whales associated with fishing boats in Norway

Funding: Ichimura Foundation of New Technology Japan Society for the Promotion of Science Postdoctoral Fellowships Research Abroad Mitsui and Co. Environment Fund.Top marine predators, such as odontocetes, pinnipeds, and seabirds, are known to forage around fishing boats as fishermen aggregate and/or discard their prey. Recently, incidents of humpback whales interacting with fishing boats have been reported. However, whether humpback whales utilise discard fish as a food source and how they forage around fishing boats is unknown. This study reports, for the first time, the foraging behaviour of a humpback whale around fishing boats. Three whales were tagged using a suction-cup tag containing a video camera, and a behavioural data logger in the coastal area of Tromsø, Norway. Video data from one tagged whale showed that the whale remained in close vicinity of fishing boats for 43 min, and revealed the presence of large numbers of dead fish, fish-eating killer whales, fishing boats, and fishing gear. In waters with large numbers of dead fish, the whale raised its upper jaw, a motion associated with engulfing discard fish from fishing boats, and this feeding behaviour differed markedly from lunge-feeding observed in two other whales in the same area. This behaviour was defined as “pick-up feeding”. No lunge feeding was seen on the data logger when the whale foraged around fishing boats. This study highlights a novel humpback whale foraging strategy: low energy gain from scattered prey but also low energy costs as high-energy lunge feeding is not required.Publisher PDFPeer reviewe

Killer whales are attracted to herring fishing vessels

ABSTRACT: Marine mammals and fisheries often target the same resources, which can lead to operational interactions. Potential consequences of operational interaction include entanglements and damaged or reduced catches but also enhanced foraging opportunities, which can attract marine mammals to fishing vessels. Responsible fisheries management therefore requires detailed knowledge of the impact of these interactions. In northern Norway, killer whales Orcinus orca are frequently observed in association with large herring aggregations during the winter. We use a combination of biotelemetry and fisheries data to study if, to what extent and at what distances killer whales are attracted to fishing activity. Twenty-five satellite transmitters were deployed on killer whales at herring overwintering and spawning grounds, often near fishing vessels. Over 50% of the killer whale core areas of high usage overlapped with the fisheries core areas, and individual whales spent up to 34% of their time close to active fishing. We used a 3-state hidden Markov model to assess whether killer whale movements were biased towards fishing activities. Of the overall whale movements, 15% (CI = 11-21%) were biased towards fishing activities, with marked heterogeneity among individuals (0-57%). During periods of active fishing, whale movements were biased towards fishing events 44% (CI = 24-66%) of the time, with individual percentages ranging from 0 to 79%. Whales were more likely to be attracted when they were within 20 km. This information can be used in fishery management to consider potential consequences for fishers and whales.publishedVersio

Round-trip migration and energy budget of a breeding female humpback whale in the Northeast Atlantic

In the northern hemisphere, humpback whales (Megaptera novaeangliae) typically migrate between summer/autumn feeding grounds at high latitudes, and specific winter/spring breeding grounds at low latitudes. Northeast Atlantic (NEA) humpback whales for instance forage in the Barents Sea and breed either in the West Indies, or the Cape Verde Islands, undertaking the longest recorded mammalian migration (~ 9 000 km). However, in the past decade hundreds of individuals have been observed foraging on herring during the winter in fjord systems along the northern Norwegian coast, with unknown consequences to their migration phenology, breeding behavior and energy budgets. Here we present the first complete migration track (321 days, January 8th, 2019—December 6th, 2019) of a humpback whale, a pregnant female that was equipped with a satellite tag in northern Norway. We show that whales can use foraging grounds in the NEA (Barents Sea, coastal Norway, and Iceland) sequentially within the same migration cycle, foraging in the Barents Sea in summer/fall and in coastal Norway and Iceland in winter. The migration speed was fast (1.6 ms-1), likely to account for the long migration distance (18 300 km) and long foraging season, but varied throughout the migration, presumably in response to the calf’s needs after its birth. The energetic cost of this migration was higher than for individuals belonging to other populations. Our results indicate that large whales can modulate their migration speed to balance foraging opportunities with migration phenology, even for the longest migrations and under the added constraint of reproduction

Seamounts in the OSPAR maritime area - from species to ecosystems

This report was prepared by the Institute of Marine Research, Norway, for the Norwegian Environment Agency, as part of Norway´s contribution to OSPAR. The report summarizes the latest knowledge on species and habitats associated with seamounts in the OSPAR Regions I, IV and V. Knowledge was sought from published literature, reports and online marine data archives. The global bathymetry model of Harris et al. (2014) predicts that 161 seamounts occurr within the OSPAR maritime area. Not all of these have been charted or studied, and the literature and bathymetry database review in this report resulted in a much shorter list of 100 seamounts or seamount-like features within the deep seas of OSPAR, i.e. regions I, IV and V. Published literature from the OSPAR area documented that there is knowledge of planktonic organisms for 11 seamounts, information on benthic species for 24 seamounts, and of fish from 16 seamounts. The best described component is the benthos with a total of 49 peer-reviewed papers. The global knowledge of seamounts (and a few studies from the NE Atlantic) suggests that seamounts are inhabited by species from the regional species pool within the biogeographical zones they occur. At individual seamounts the structure of species assemblages and production patterns are variable over time and modified by factors such as the local and regional hydrography and circulation which are sometimes modified by the seamounts themselves. Other significant factors causing variability are the varying depths of slopes and summits in relation to the depth of the euphotic zone, the depth of summits relative to mesopelagic scattering layers, and presumably the distance from continents, islands and wider areas such banks and ridges. Furthermore, seamounts represent isolated shallows in the deep-sea and may have several important local and regional functions. However, within the OSPAR maritime area, few studies have produced more than descriptive data, hence a major shortage is the lack of quantitative information on species occurrences as well as studies measuring processes and documenting functions. The roles of seamounts at regional scales, e.g. as stepping stones for species across wider ocean areas, have only been incompletely studied. Seamounts apparently constitute patches of suitable habitats for aggregating commercially valuable fish species that are relatively easy to locate and target, and if not properly controlled, to overexploit. This is known from the OSPAR region V, e.g. from historical depletion of orange roughy west of the British Isles and sharp declines of alfonsino aggregations on seamounts north of the Azores. Also, seamounts are features likely to have Vulnerable Marine Ecosystems (VMEs) (sensu FAO, 2009), primarily in the form of structure-forming coral and sponge aggregations. These require special protective action such as called for by the UN General Assembly and OSPAR, and accordingly several nations, the EU and the Northeast Atlantic Fisheries Commission (NEAFC) implemented measures to prevent further signficant adverse impacts from bottom fishing. Studies at many seamounts in OSPAR have shown that many summits have rich occurrence of VME indicator taxa and probably VMEs. Significant adverse impacts of past bottom fishing have been well documented in some slope and shelf habitats, but studies on seamounts have been scattered, and as yet there is not enough information to assess the overall status of VMEs on seamounts in Region I, IV and V.publishedVersio

Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022

Cruise no.: 2022703 : The 2022 survey of harp and hooded seal pup production in the Greenland Sea was carried out to obtain updated estimates to be used to assess current status of these two seal stocks. Since a similar survey in 2018 indicated a 40% reduction in harp seal pup production since the 2012 survey, and the continued lack of increase in pup production of the severely depleted hooded seal stock despite its protection from hunting since 2007, a new survey after a period of only 4 years was urgent. The survey was carried out using well established methodologies for these species, including 1) reconnaissance of the drift ice breeding habitat from a helicopter based on the research icebreaker R/V Kronprins Haakon and a fixed-wing aircraft stationed at Constable Pynt in East Greenland, 2) deploying GPS beacons around the identified breeding areas to monitor its displacement in the East Greenland Current, 3) carrying out staging surveys to monitor the pup age structure and estimate the optimal day of pup counting as well as correction factors accounting for pups not present on the ice at the time of counting, and 4) conducting aerial photographic surveys using the fixed-wing aircraft. Ice conditions in the Greenland Sea were similar as those experienced in 2018, with a relatively narrow band of pack ice over the shelf break near the coast of East Greenland. Seal whelping patches were initially discovered on March 21 & 22nd, within an area stretching from 72°53’N / 16°42’W in the north to 71°51’N / 17°30’W in the south. Five GPS beacons were deployed at the main whelping patches within this area, allowing us to track the continuous drift due to strong northerly winds during the period between initial reconnaissance and the final pup counting. Pup staging surveys were carried out on March 22nd, 23rd, 25th, 28th and 30th, providing us with a solid dataset with which to assess the development of pup age dynamics, determine the optimal day for photographic surveys, and to estimate correction factors to account for pups absent from the ice during the photographic surveys. The final photographic surveys were carried out on March 28th in a relatively narrow (20-30 nm) N/S band stretching from 71°00’N / 20°00’W in the NE to 69°34’N / 20°36’W in the SW. In total, 2,463 images were obtained during the aerial photographic survey, and following pre-processing (georeferencing and ortorectification), these will be analysed both manually and using dedicated machine learning systems, to determine the number of pups present in images. Results will be used to estimate the total 2022 pup production for each species and will also be combined with estimates from previous years to estimate the population sizes using the dedicated population dynamics model. The entire updated dataset will be made available to the upcoming ICES benchmarking meeting for harp and hooded seal population modelling, and results will finally be evaluated at the upcoming meeting of the ICES WGHARP working group in 2023.Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022publishedVersio

Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022

Source at https://www.hi.no/en/hi/nettrapporter/toktrapport-en-2022-7.Cruise no.: 2022703 : The 2022 survey of harp and hooded seal pup production in the Greenland Sea was carried out to obtain updated estimates to be used to assess current status of these two seal stocks. Since a similar survey in 2018 indicated a 40% reduction in harp seal pup production since the 2012 survey, and the continued lack of increase in pup production of the severely depleted hooded seal stock despite its protection from hunting since 2007, a new survey after a period of only 4 years was urgent. The survey was carried out using well established methodologies for these species, including 1) reconnaissance of the drift ice breeding habitat from a helicopter based on the research icebreaker R/V Kronprins Haakon and a fixed-wing aircraft stationed at Constable Pynt in East Greenland, 2) deploying GPS beacons around the identified breeding areas to monitor its displacement in the East Greenland Current, 3) carrying out staging surveys to monitor the pup age structure and estimate the optimal day of pup counting as well as correction factors accounting for pups not present on the ice at the time of counting, and 4) conducting aerial photographic surveys using the fixed-wing aircraft. Ice conditions in the Greenland Sea were similar as those experienced in 2018, with a relatively narrow band of pack ice over the shelf break near the coast of East Greenland. Seal whelping patches were initially discovered on March 21 & 22nd, within an area stretching from 72°53’N / 16°42’W in the north to 71°51’N / 17°30’W in the south. Five GPS beacons were deployed at the main whelping patches within this area, allowing us to track the continuous drift due to strong northerly winds during the period between initial reconnaissance and the final pup counting. Pup staging surveys were carried out on March 22nd, 23rd, 25th, 28th and 30th, providing us with a solid dataset with which to assess the development of pup age dynamics, determine the optimal day for photographic surveys, and to estimate correction factors to account for pups absent from the ice during the photographic surveys. The final photographic surveys were carried out on March 28th in a relatively narrow (20-30 nm) N/S band stretching from 71°00’N / 20°00’W in the NE to 69°34’N / 20°36’W in the SW. In total, 2,463 images were obtained during the aerial photographic survey, and following pre-processing (georeferencing and ortorectification), these will be analysed both manually and using dedicated machine learning systems, to determine the number of pups present in images. Results will be used to estimate the total 2022 pup production for each species and will also be combined with estimates from previous years to estimate the population sizes using the dedicated population dynamics model. The entire updated dataset will be made available to the upcoming ICES benchmarking meeting for harp and hooded seal population modelling, and results will finally be evaluated at the upcoming meeting of the ICES WGHARP working group in 2023