In the Southern Hemisphere and northern Indian Ocean, there are at least five populations of pygmy blue whales, Balaenoptera musculus brevicauda, residing in the Northwest Indian Ocean (NWIO, Oman), central Indian Ocean (CIO, Sri Lanka), Southwest Indian Ocean (SWIO, Madagascar to Subantarctic), Southeast Indian Ocean (SEIO, Australia to Indonesia), and Southwest Pacific Ocean (SWPO, New Zealand). Each population produces a distinctive repeated song, but none have population assessments or reliable measures of historical whaling pressure. Here we created pygmy blue whale catch time series by removing Antarctic blue whale catches using length data and then fitting generalized additive models (based on latitude, longitude, and month) to contemporary song data (largely from 1995 to 2023) to allocate historical catches to the five populations. Most pygmy blue whale catches (97% of 12,207) were taken by Japanese and Soviet operations during 1959/1960 to 1971/1972, with the highest totals taken from the SWIO (6514), SEIO (2593), and CIO (2023), and lower catches from the NWIO (549) and SWPO (528). The resulting predicted annual catch assignments provide the first indication of the magnitude of whaling pressure on each population and are a key step toward assessing the status of these five pygmy blue whale populations.

The use of satellite tags has yielded important information to better understand cetacean ecology and to improve cetacean conservation. However, tag deployment duration has been highly variable and typically shorter than their battery life on most large whale species. Between 2011 and 2018, 80 consolidated satellite tags were deployed in North Atlantic humpback whales (Megaptera novaeangliae) in the Gulf of Maine (GoM) to study whale movements, to assess tag impacts, and to understand causes of tag rejection and tag failure. The strong site fidelity of individual whales to the GoM, long feeding ground residency, and high observer effort allowed repeated sightings of animals instrumented with satellite tags. In early deployments multiple structural deficiencies were documented on the tags, revealing the need to improve the mechanical design and manufacturing of the instruments. These tag deficiencies not only resulted in short tag transmission durations, but also in negative health impacts on individual animals. Incremental modifications to the mechanical design and the manufacturing processes to resolve the observed deficiencies included: (1) changes in the anchor tip, retention devices, and anchor articulation, (2) the removal of the interface between the transmitter housing and the anchor and (3) the redesign of the posterior end of the tag. More robust instruments were produced by welding deficient tag parts or by using 3‐dimension (3‐D) metal printing processes to manufacture integrated instruments. Deployments of redesigned satellite tags resulted in 65–85% significantly longer average transmission durations when compared to earlier designs that showed structural deficiencies. This study highlights the importance of developing satellite tagging technology in association with follow‐up monitoring of tagged individuals and provides new tag designs that are structurally more robust and less impactful for use with large cetaceans.

Hundreds of large whales have been tracked using consolidated (Type‐C) satellite tags, yet there have been few studies on their impacts on whale health. In 2011, we initiated the first study designed to evaluate the effects of these tags on a baleen whale. Between 2011 and 2018, we tagged 79 North Atlantic humpback whales (Megaptera novaeangliae) in the Gulf of Maine. We initially deployed commonly‐used tags with an articulation between the anchor and transmitter (n = 35, 2011–12), before evidence of breakage prompted the development and use of more robust, integrated tags (n = 45). Tagged individuals were photographed immediately before, during and up to 11 years after tagging. They were re‐encountered on an average of 41.3 days (SD = 44.3), yielding 2,971 photographed sightings through 2022. An objective scoring system was developed to characterise tag‐site tissue responses based on photographs and to identify risk factors for prolonged healing. The initial tissue response to tagging was minimal, followed by skin loss around the tag, sometimes a degree of subcutaneous swelling, occasional extrusion of blubber, changes in skin colour, local depression formation around the implant site, tag loss and skin healing over the tag site, sometimes with a depression remaining. At last sighting, most non‐integrated and integrated tag sites exhibited small, shallow skin depressions (58.8% and 66.7%, respectively). Some exhibited deeper depressions with differing adjacent skin coloration (26.5% and 15.6%, respectively) or barely detectable marks (11.8% and 15.6%, respectively). Mild subcutaneous swellings occasionally persisted at the tag site, but this was uncommon for both tag designs (2.9% and 2.2%, respectively). More severe tissue responses were associated with non‐integrated tags and placements lower on the body. This study highlights the importance of using robust tag designs to minimise negative effects from Type‐C tags. Furthermore, because tag placement was shown to affect outcome, precision equipment, experienced taggers and vessel operators are critical for optimal deployment.

Annex A: List of Participants Annex B: Agenda Annex C: List of Documents How to cite: International Whaling Commission, 2023. Report of the Scientific Committee: Annex A-C. J. Cetacean Res. Manage. (Suppl.). 24: 191-206.

Seven passive acoustic surveys for marine mammal sounds were conducted by deploying sonobuoys along ship tracks during Antarctic voyages spanning years 2006-2021. These surveys included nearly 330° of longitude throughout Antarctic (south of 60°S) and sub-Antarctic (between 50-60°S) latitudes. Here, we summarise the presence of calls from critically endangered Antarctic blue whales (Balaenoptera musculus intermedia) detected on all seven of these surveys. We describe and compare the spatial distribution of detections of three different types of Antarctic blue whale calls: unit-A, Z-calls, and D-calls. Three sets of voyages partially overlapped spatially but in different years, providing three regions (Indian Sector, Dumont d’Urville Sea, Ross Sea) to investigate differences over time for these three different call types. The proportion of sonobuoys with calls present was significantly higher in the more recent years for seven of the 15 combinations of years, regions, and call type. The proportion of sonobuoys with calls present was significantly lower only for one of the 15 combinations (unit A in the Ross Sea between 2015 vs 2017), and not significantly different for the remaining seven pairwise comparisons. We discuss possible explanations for these observations including: differences in probability of detection, whale behaviour, whale distribution, and abundance. These explanations are not mutually exclusive and cannot yet be resolved without application of complex analytical methods and collection of additional data. Lastly, we discuss future work that could help clarify the contributions of each of these potential drivers of acoustic detection. We propose continued acoustic data collection, application of new analytical methods, and collection of other synergistic data from Antarctic blue whales on their feeding grounds as a basis for future work on this species. This could provide a cost effective and holistic means of monitoring their status after the effects of 20th century industrial whaling, as well as their responses to natural and anthropogenic changes to their main prey, Antarctic krill, and a changing climate.

How animals navigate during long-distance migration remains a mystery. Many theories have been proposed1 (Keeton, 1979), with the Earth’s magnetic field emerging as a clear potential source of orientational information for navigational decision-making across diverse taxa2 (Putman, 2022). Yet, the mechanics involved in magnetic navigation remain unknown3 (Schneider et al., 2023). Globally distributed records available from historic whaling4-5 (AOWLD, 2023; Yablokov et al., 1998) in combination with modern satellite-tracking datasets6 (Horton et al., 2022) for baleen whales create a unique opportunity to illuminate the mechanics of cetacean navigation. Here, we show that baleen whale migratory destinations over the last >200 years are systematically distributed in horizontal plane magnetic coordinates. Specifically, blue (Balaenoptera musculus), bowhead (Balaena mysticetus), fin (Balaenoptera physalus), gray (Eschrichtius robustus), humpback (Megaptera novaeangliae), and right (Eubalaena spp.) whales non-randomly inhabit areas where magnetic declination (MD) closely approximates integer and half-integer multiples of the Earth’s 23.44° axial tilt. Our findings, which are highly reproducible through both space and time, demonstrate that baleen whale navigation between seasonal habitats occurs via the integration of magnetic and astronomic orientation cues3. By referencing MD values to the rise and set azimuths of the Sun, baleen whale movements define mechanistic horizontal plane heliomagnetic coordinate trajectories across all ocean basins.

Southern hemisphere humpback whale (Megaptera novaeangliae, SHHW) breeding populations follow a high-fidelity Antarctic krill (Euphausia superba) diet while feeding in distinct sectors of the Southern Ocean. Their capital breeding life history requires predictable ecosystem productivity to fuel migration and migration-related behaviours. It is therefore postulated that populations feeding in areas subject to the strongest climate change impacts are more likely to show the first signs of a departure from a high-fidelity krill diet. We tested this hypothesis by investigating blubber fatty acid profiles and skin stable isotopes obtained from five SHHW populations in 2019, and comparing them to Antarctic krill stable isotopes sampled in three SHHW feeding areas in the Southern Ocean in 2019. Fatty acid profiles and δ13C and δ15N varied significantly among all five populations, however, calculated trophic positions did not (2.7 to 3.1). Similarly, fatty acid ratios, 16:1ω7c/16:0 and 20:5ω3/22:6ω3 were above 1, showing that whales from all five populations are secondary heterotrophs following an omnivorous diet with a diatom-origin. Thus, evidence for a potential departure from a high-fidelity Antarctic krill diet was not seen in any population. δ13C of all populations were similar to δ13C of krill sampled in productive upwelling areas or the marginal sea-ice zone. Consistency in trophic position and diet origin but significant fatty acid and stable isotope differences demonstrate that the observed variability arises at lower trophic levels. Our results indicate that, at present, there is no evidence of a divergence from a high-fidelity krill diet. Nevertheless, the characteristic isotopic signal of whales feeding in productive upwelling areas, or in the marginal sea-ice zone, implies that future cryosphere reductions could impact their feeding ecology.

Photo-identifications of Antarctic blue whales (Balaenoptera musculus intermedia) collected from 2003/2004 to 2018/2019 were used in a capture-recapture analysis to estimate abundance and population growth rate for the circumpolar Antarctic. Two capture-recapture models, POPAN and Pradel, were applied to these data. Estimates of annual abundance and their variances from the left and right side photo data were inferred using multimodel averaging, weighted by corrected Akaike information criterion (AICc), of 26 model configurations with prespecified survival rates from .75 to 1.0. These estimates based on the left and right side databases were then combined using inverse-variance averaging into single estimates for each year. The POPAN superpopulation estimate (total number of individuals present during the sampling period) was 3,506 whales, 95% confidence interval (CI) [2,107, 5,832]. The estimated abundance from the final year of the study in 2018/2019 was 1,817 whales, 95% CI [714, 4,624]. The abundance estimates in this study may be biased downwards due to capture heterogeneity as a result of unequal spatial sampling. Population growth rate estimates were 11% from Pradel and 10% from POPAN. These rates were within the confidence interval estimated by a previous study for Antarctic blue whale population growth rate.

Data collection facilitated by remotely piloted aircraft (RPA) has proven to be revolutionary in many disciplines including for research in extreme environments. Here we assess current use and utility of small multirotor remotely piloted aircraft (RPAs) for the challenging role of facilitating ship-based cetacean research in Antarctica. While such aircraft are now used routinely in sheltered environments in and off Antarctica, a comprehensive literature review found that RPA-mediated cetacean research conducted from ships at sea and outside of the Antarctic Peninsula region was relatively uncommon. In order to determine the potential utility of ship-based multirotor RPA operations for cetacean research, we repeatedly deployed small RPAs during a multidisciplinary research voyage in maritime East Antarctica to collect scientific data contributing to an understanding of krill and krill predator interactions. RPA flight metrics (duration, height, length, speed, distance from ship, battery drainage, satellites acquired) were compared to ship underway environmental sampling data. At a mean duration of 12 minutes, these 139 RPA flights were relatively short yet adequate to achieve the science intended, namely a range of cetacean related data streams including photogrammetry, photo identification, behavioural observations and whale blow sampling in addition to water sampling and collection of general scenic imagery. RPA flight operations were constrained by wind speed but not by air temperature with flights undertaken throughout the full range of air temperatures experienced (down to –9.5°C) but not throughout the full range of wind speeds experienced. For a 12-minute flight duration, battery drainage was around 60% indicating that the RPAs were rarely pushed to their operational limit. There was little evidence that the cold impacted RPA lithium battery performance with estimated maximum flight time within approximately 10% of expected flight time for the RPA platforms most used. Whist small multirotor RPAs are rarely applied to cetacean related research in maritime East Antarctica, we demonstrate their value and potential to deliver data critical to address knowledge gaps that challenge the effective management of both krill and their predators.

Southern Ocean humpback whales Megaptera novaeangliae are capital breeders, breeding in the warm tropics/subtropics in the winter and migrating to nutrient-rich Antarctic feeding grounds in the summer. The classic feeding model is for the species to fast while migrating and breeding, surviving on blubber energy stores. Whilst northern hemisphere humpback whales are generalists, southern hemisphere counterparts are perceived as krill specialists, but for many populations, uncertainties remain regarding their diet and preferred feeding locations. This study used bulk and compound-specific stable isotope analyses and isoscape-based feeding location assignments to assess the diet, trophic ecology and likely feeding areas of humpback whales sampled in the Ross Sea region and around the Balleny Islands. Sampled whales had a mixed diet of plankton, krill and fish, similar to the diet of northern hemisphere humpback whales. Proportions of fish consumed varied but were often high (2-60%), thus challenging the widely held paradigm of Southern Ocean humpback whales being exclusive krill feeders. These whales had lower 15 N values and trophic position estimates than their northern hemisphere counterparts, likely due to lower Southern Ocean baseline 15 N surface water values and a lower percentage consumption of fish, respectively. Most whales fed in the Ross Sea shelf/slope and Balleny Islands high-productivity regions, but some isotopically distinct whales (mostly males) fed at higher trophic levels either around the Balleny Islands and frontal upwelling areas to the north, or en route to Antarctica in temperate waters off southern Australia and New Zealand. These results support other observations of humpback whales feeding during migration, highlighting the species’ dietary plasticity, which may increase their foraging and breeding success and provide them with greater resilience to anthropogenically mediated ecological change. This study highlights the importance of combining in situ field data with regional-scale isoscapes to reliably assess trophic structure and animal feeding locations, and to better inform ecosystem conservation and management of marine protected areas.

During three surveys in the austral summers of 2013, 2015, 2019, data on Antarctic blue whale blow rates, dive times, swim speeds, and broadscale movements were collected using video photogrammetric tracking and intra-voyage photo-identification. A total of 24.4 hours of video observations were suitable for blow interval or movement analysis. Similar to other blue whale populations, Antarctic blue whale dive behaviour comprised a sequence of short dives followed by a long dive with a mean dive time for short dives of 17.6 s, and a mean long dive time of 189.3 s. Two separate methods were used to estimate the average blow rate for Antarctic blue whales, giving estimates of 59.7 and 63.2 blows per hour. The overall mean swim speed over the course of all suitable video track segments was 1.59 ms -1 , but there were significant differences between years in the mean of the overall movement rate for each track; average movement rates were lower in 2015 compared to 2013 and 2019 (0.90 ms -1 , 1.84 and 1.55 ms -1 respectively), with higher rates of turning in 2015. In 2019, there was faster overall movement through the study area in a consistent direction. The total number of photo-identified blue whales re-sighted intra-season in 2013 was nine (out of 50 identified individuals); in 2015 it was seven (out of 46); in 2019 two (out of 25). Whales remained for several days with little overall movement within the 2015 study area, whereas they were moving through the study area in 2019, which would explain the low number of intra-season resights. The predominant heading in 2019 was towards the area of Antarctic blue whale concentrations at the entrance to the Ross Sea observed in previous years. The photo-identification data also show a high proportion of resighted whales with coherent movements. This suggests that Antarctic blue whales might travel together, at least over periods of several days or sometimes up to a month. The differences between behaviours in 2015 and 2019 in particular may be related to differences in the characteristics of krill swarms between the study areas.

In understanding the impact of commercial whaling, it is important to estimate the mixing of low latitude breeding populations on Antarctic feeding grounds, particularly the endangered humpback whale populations of Oceania. This paper estimates the degree of genetic differentiation among the putative populations of Oceania (New Caledonia, Tonga, the Cook Islands and French Polynesia) and Australia (western Australia and eastern Australia) using ten microsatellite loci and mtDNA, assesses the power of the data for a mixed-stock analysis, determines ways to improve statistical power for future studies and estimates the population composition of Antarctic samples collected in 2010 south of New Zealand and eastern Australia. A large proportion of individuals could not be assigned to a population of origin (> 52%) using a posterior probability threshold of > 0.90. The mixed-stock analysis simulations however, produced accurate results with humpback whales reapportioned to their population of origin above the 90% threshold for western Australia, New Caledonia and Oceania grouped using a combined mtDNA and microsatellite dataset. Removing the Cook Islands, considered a transient region for humpback whales, from the simulation analysis increased the ability to reapportion Tonga from 86% to 89% and French Polynesia from 89% to 92%. Breeding ground sample size was found to be a factor influencing the accuracy of population reapportionment whereas increasing the mixture or feeding ground sample size improved the precision of results. The mixed-stock analysis of our Antarctic samples revealed substantial contributions from both eastern Australia (53.2%, 6.8% SE) and New Caledonia (43.7%, 5.5% SE) [with Oceania contributing 46.8% (5.9% SE)] but not western Australia. Despite the need for more samples to improve estimates of population allocation, our study strengthens the emerging genetic and non-genetic evidence that Antarctic waters south of New Zealand and eastern Australia are used by humpback whales from both eastern Australia and the more vulnerable breeding population of New Caledonia, representing Oceania.

To understand the scope and scale of the loss of biodiversity, tools are required that can be applied in a standardized manner to all species globally, spanning realms from land to the open ocean. We used data from the International Union for the Conservation of Nature Red List to provide a synthesis of the conservation status and extinction risk of cetaceans. One in 4 cetacean species (26% of 92 species) was threatened with extinction (i.e., critically endangered, endangered, or vulnerable) and 11% were near threatened. Ten percent of cetacean species were data deficient, and we predicted that 2–3 of these species may also be threatened. The proportion of threatened cetaceans has increased: 15% in 1991, 19% in 2008, and 26% in 2021. The assessed conservation status of 20% of species has worsened from 2008 to 2021, and only 3 moved into categories of lesser threat. Cetacean species with small geographic ranges were more likely to be listed as threatened than those with large ranges, and those that occur in freshwater (100% of species) and coastal (60% of species) habitats were under the greatest threat. Analysis of odontocete species distributions revealed a global hotspot of threatened small cetaceans in Southeast Asia, in an area encompassing the Coral Triangle and extending through nearshore waters of the Bay of Bengal, northern Australia, and Papua New Guinea and into the coastal waters of China. Improved management of fisheries to limit overfishing and reduce bycatch is urgently needed to avoid extinctions or further declines, especially in coastal areas of Asia, Africa, and South America.

Photo-identification studies of humpback whales off eastern Australia show low levels of movement between eastern Australia and New Caledonia whales. Some eastern Australian humpback whales migrate through the southern waters of New Zealand on route to Antarctic feeding areas. Photoidentification studies have shown that the waters near the Balleny Islands, in Antarctic Area V, are a feeding area for some eastern Australian humpback whales. However, such studies provide no details of the routes taken between New Zealand and Australia and to and from Antarctic feeding areas. Sixteen humpback whales were satellite-linked radio tagged off Eden NSW in 2008. The number and duration of the tag positions reported revealed complete migratory transits from Eden to Antarctic Area V and IV feeding areas. Photographs of the Eden humpback whales were compared to the Hervey Bay photo-identification catalogue and yielded two matches, identified from lateral body marks and dorsal fins. This study provides the first evidence that during the southern migration some humpback whales stopover at Hervey Bay and also migrate past Eden on the NSW coast. The tracks of the two whales from Eden showed that a male sighted in Hervey Bay in the same season moved southeast from Eden towards southern New Zealand. A female with site-fidelity to Hervey Bay in previous seasons, accompanied by a calf when the tag was deployed, moved down and around the coast of Victoria, across Bass Strait and then southwest into the Antarctic Area IV feeding area. Eden may be a migratory hub for humpback whales departing from and approaching the east coast of Australia. This study suggests that eastern Australian humpback whales may exhibit a more diverse range of feeding destinations, after leaving Australian coastal waters, than previously reported.

Satellite tags were deployed on 50 east Australian humpback whales (breeding stock E1) between 2008 and 2010 on their southward migration, northward migration and feeding grounds in order to identify and describe migratory pathways, feeding grounds and possible calving areas. At the time, these movements were not well understood and calving grounds were not clearly identified. To the best of our knowledge, this dataset details all long-term, implantable tag deployments that have occurred to date on breeding stock E1. As such, these data provide researchers, regulators and industry with clear and valuable insights into the spatial and temporal nature of humpback whale movements along the eastern coastline of Australia and into the Southern Ocean. As this population of humpback whales navigates an increasingly complex habitat undergoing various development pressures and anthropogenic disturbances, in addition to climate-mediated changes in their marine environment, this dataset may also provide a valuable baseline.At the time these tracks were generated, these were the first satellite tag deployments intended to deliver long-term, detailed movement information on east Australian (breeding stock E1) humpback whales. The tracking data revealed previously unknown migratory pathways into the Southern Ocean, with 11 individuals tracked to their Antarctic feeding grounds. Once assumed to head directly south on their southern migration, five individuals initially travelled west towards New Zealand. Six tracks detailed the coastal movement of humpback whales migrating south. One tag transmitted a partial southern migration, then ceased transmissions only to begin transmitting eight months later as the animal was migrating north. Northern migration to breeding grounds was detailed for 13 individuals, with four tracks including turning points and partial southern migrations. Another 14 humpback whales were tagged in Antarctica, providing detailed Antarctic feeding ground movements.Broadly speaking, the tracking data revealed a pattern of movement where whales were at their northern limit in July and their southern limit in March. Migration north was most rapid across the months of May and June, whilst migration south was most rapid between November and December. Tagged humpback whales were located on their Antarctic feeding grounds predominantly between January and May and approached their breeding grounds between July and August. Tracking distances ranged from 68 km to 8580 km and 1 to 286 days. To the best of our knowledge, this dataset compiles all of the long-term tag deployments that have occurred to date on breeding stock E1.

White-capped Albatrosses Thalassarche steadi breed only on New Zealand's sub-Antarctic islands, principally the Auckland Islands. The species is commonly caught as bycatch in global longline and trawl fisheries, and it has been estimated that 8 000 birds are killed each year. In December or January between 2006 and 2017 we undertook annual population censuses of the White-capped Albatrosses breeding at the Auckland Islands using aerial photography. Estimated annual counts for the three breeding sites were adjusted using estimates of the proportion of birds clearly not associated with an active nest (loafers), to estimate annual breeding pairs for each breeding season. The estimated mean number of annual breeding pairs in the Auckland Islands during this period was 89 846 with high inter-annual variability (range: 74 031-116 025). Over the 12 years of the study adjusted counts for all sites combined showed a negative linear trend but this relationship was not statistically significant. Similar analyses using TRIM classified the population as 'stable'. Given the estimated number of annual breeding pairs and the high frequency of biennial breeding it is likely that fisheries bycatch, if it has been estimated accurately, is impacting this population. Continuation of annual monitoring is recommended to increase the precision of the estimated population trend and help determine if the high levels of bycatch across multiple fisheries are sustainable in the long term.

Satellite tags were deployed on two Antarctic blue whales (Balaenopteramusculusintermedia) in the east Antarctic sector of the Southern Ocean as part of the International Whaling Commission's Southern Ocean Research Partnership initiative. The satellite tracks generated are the first and currently, the only, satellite telemetry data that exist for this critically endangered species. These data provide valuable insights into the movements of Antarctic blue whales on their Antarctic feeding ground. The data were collected between February and April 2013 and span a 110° longitudinal range.This dataset is the first and only detailed movement data that exist for this critically endangered species. As such, this dataset provides the first measures of movement rates (distances travelled, speeds) and movement behaviour (distinguishing transit behaviour from area restricted search behaviour) within the Southern Ocean. These movement-based measures are critical to the ongoing management of Antarctic blue whales as they recover from commercial whaling as they provide insight into foraging behaviour, habitat use, population structure and overlap with anthropogenic threats.

Marine Mammal ScienceEarly View NOTE First satellite-tracked movements of pygmy blue whales (Balaenoptera musculus brevicauda) in New Zealand waters Kimberly T. Goetz, Corresponding Author Kimberly T. Goetz kim.goetz@noaa.gov orcid.org/0000-0002-1356-0512 National Institute of Water & Atmospheric Research, Wellington, New Zealand Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, Washington, USA Correspondence Kimberly T. Goetz, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98115-6349. Email: kim.goetz@noaa.govSearch for more papers by this authorSimon J. Childerhouse, Simon J. Childerhouse Cawthron Institute, Nelson, New Zealand Contribution: Data curation, Writing - review & editingSearch for more papers by this authorDavid Paton, David Paton Blue Planet Marine, Canberra, Australia Contribution: Data curation, Writing - review & editingSearch for more papers by this authorMike Ogle, Mike Ogle Department of Conservation, Takaka, New Zealand Contribution: Data curation, Writing - review & editingSearch for more papers by this authorKrista van der Linde, Krista van der Linde National Institute of Water & Atmospheric Research, Wellington, New ZealandSearch for more papers by this authorRochelle Constantine, Rochelle Constantine orcid.org/0000-0003-3260-539X University of Auckland, School of Biological Sciences and Institute of Marine Sciences, Auckland, New Zealand Contribution: Conceptualization, Formal analysis, Methodology, Writing - original draftSearch for more papers by this authorMichael C. Double, Michael C. Double Australian Marine Mammal Center, Australian Antarctic Division, Hobart, Australia Contribution: ​Investigation, Methodology, Resources, Writing - review & editingSearch for more papers by this authorVirginia Andrews-Goff, Virginia Andrews-Goff orcid.org/0000-0002-4609-7317 Australian Marine Mammal Center, Australian Antarctic Division, Hobart, Australia Contribution: Methodology, Writing - review & editingSearch for more papers by this authorAlexandre N. Zerbini, Alexandre N. Zerbini orcid.org/0000-0002-9776-6605 Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, Washington, USA Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA Marine Ecology and Telemetry Research, Seabeck, Washington, USASearch for more papers by this authorPaula A. Olson, Paula A. Olson Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, California, USA Contribution: Data curation, ​Investigation, Methodology, Resources, Writing - review & editingSearch for more papers by this author Kimberly T. Goetz, Corresponding Author Kimberly T. Goetz kim.goetz@noaa.gov orcid.org/0000-0002-1356-0512 National Institute of Water & Atmospheric Research, Wellington, New Zealand Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, Washington, USA Correspondence Kimberly T. Goetz, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98115-6349. Email: kim.goetz@noaa.govSearch for more papers by this authorSimon J. Childerhouse, Simon J. Childerhouse Cawthron Institute, Nelson, New Zealand Contribution: Data curation, Writing - review & editingSearch for more papers by this authorDavid Paton, David Paton Blue Planet Marine, Canberra, Australia Contribution: Data curation, Writing - review & editingSearch for more papers by this authorMike Ogle, Mike Ogle Department of Conservation, Takaka, New Zealand Contribution: Data curation, Writing - review & editingSearch for more papers by this authorKrista van der Linde, Krista van der Linde National Institute of Water & Atmospheric Research, Wellington, New ZealandSearch for more papers by this authorRochelle Constantine, Rochelle Constantine orcid.org/0000-0003-3260-539X University of Auckland, School of Biological Sciences and Institute of Marine Sciences, Auckland, New Zealand Contribution: Conceptualization, Formal analysis, Methodology, Writing - original draftSearch for more papers by this authorMichael C. Double, Michael C. Double Australian Marine Mammal Center, Australian Antarctic Division, Hobart, Australia Contribution: ​Investigation, Methodology, Resources, Writing - review & editingSearch for more papers by this authorVirginia Andrews-Goff, Virginia Andrews-Goff orcid.org/0000-0002-4609-7317 Australian Marine Mammal Center, Australian Antarctic Division, Hobart, Australia Contribution: Methodology, Writing - review & editingSearch for more papers by this authorAlexandre N. Zerbini, Alexandre N. Zerbini orcid.org/0000-0002-9776-6605 Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, Washington, USA Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA Marine Ecology and Telemetry Research, Seabeck, Washington, USASearch for more papers by this authorPaula A. Olson, Paula A. Olson Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, La Jolla, California, USA Contribution: Data curation, ​Investigation, Methodology, Resources, Writing - review & editingSearch for more papers by this author First published: 25 September 2021 https://doi.org/10.1111/mms.12876 Funding information: National Institute of Water and Atmospheric Research; New Zealand Department of Conservation; OMV Ltd Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. 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Marine migratory species tend to be overlooked in marine spatial planning due to limited knowledge of their habitats and migration pathways, resulting in a disconnect between animal migration ecology and spatial management decision making. The aim of this study was to predict the migratory corridors, suitable habitats and use of marine reserves by pygmy blue whales and overlap with marine traffic. Firstly, based on available telemetry data, we analysed the home ranges, core-use areas and migratory corridors using Brownian Bridge Movement Models. Secondly, we predicted suitable habitat by modelling telemetry data against environmental predictors using Maximum Entropy modelling; and lastly we geometrically overlaid home ranges and suitable habitats with designated migration lanes, marine protected areas and marine traffic. Consistent movement of pygmy blue whales from Western Australia to the Banda and Molucca Seas in Indonesia demonstrated a high level of connectivity between the two regions. There is a discrepancy between the designated migration lanes for large whales in Indonesian marine spatial planning and migration routes suggested by this study. The home range analysis and habitat models revealed that large areas of the migration corridors, core-use, and suitable habitats are currently not protected, particularly along international waters and within the Banda and Molucca Seas. The results can aid marine conservation planning by delineating the important areas and areas with high marine traffic density to optimise migratory species protection.