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Humpback whales Megaptera noaeangliae in the Arabian Sea
Abstract
The population identity of humpback whales Megaptera novaeangliae in the Arabian Sea has long been a matter of dispute. New information is presented from this region, based upon whaling and observations conducted by the Soviet Union, primarily in November 1966. In that month, a total of 238 humpbacks were killed off the coasts of Oman, Pakistan and northwestern India; 4 others were killed in 1965. Biological examination of these whales showed that they differed significantly from Antarctic humpbacks in terms of size, coloration, body scars and pathology. In addition, analysis of the length distribution of 38 foetuses indicates that the reproductive cycle of the Arabian Sea whales was unequivocally that of a northern hemisphere population. Mean lengths were 12.8 m for males (range: 9.5 to 14.9 m, n = 126) and 13.3 m for females (range: 9.5 to 15.2 m, n = 112). All whales 12.5 m or more in length were sexually mature. Among 97 females examined, 12 (12.4%) were immature. Of the 85 mature females, 39 (45.9%) were pregnant, 3 (3.5%) were lactating, and 43 (50.6%) were resting. A more plausible pregnancy rate, adjusted for underrepresentation of lactating females, was estimated at 39%. A majority of stomachs examined contained food, including euphausiids and fish. Overall, the data presented here argue strongly that Arabian Sea humpbacks constitute a discrete population which remains in tropical waters year-round, a situation which is unique for this species.
... The humpback whale has a global distribution and undertakes some of the most extensive migrations of all mysticete species (Stone et al. 1990, Rasmussen et al. 2007, Robbins et al. 2011, moving annually between summer high-latitude feeding (H-LF) areas and low-latitude winter breeding areas (Dawbin 1966). Whaling data established that humpback whale populations globally have the same basic annual migration, with Northern and Southern Hemisphere population migrations following the respective boreal and austral seasons (Dawbin 1966), with the exception of a resident population in the Arabian Sea (Mikhalev 1997). In H-LF areas, humpback whales feed intensively on fish and zooplankton found in nutrient rich waters, resulting in substantial net gains in body mass (Chittleborough 1965). ...
... The humpback whale is therefore considered a capital breeder, supporting reproductive costs with previously stored energy supplies, contrasting with income breeders, such as most small cetaceans, which feed constantly to support reproduction (Jonsson 1997). Notably, in the Arabian Sea, an upwelling affords year-round feeding for humpback whales; therefore, this population is unique for the species in that they are income breeders (Mikhalev 1997, Papastavrou & Van Waerebeek 1997. ...
... Capital breeding, such as the classic humpback whale Megaptera novaeangliae migratory model (Chittleborough 1965, Dawbin 1966, is considered an adaptation for survival in adverse conditions, rather than a preferred mammalian breeding strategy (Houston et al. 2007). This is primarily due to the energetic costs of maintaining and converting fat stores, the dangers of any error in estimates of required capital, and the reliance on habitat and resource predictability (Jonsson 1997, Ramp et al. (Mikhalev 1997). However, with the exception of upwelling areas, most (sub-) tropical humpback whale breeding areas worldwide typically have poor productivity and low densities of potential humpback whale prey species (Papastavrou & Van Waerebeek 1997). ...
Humpback whales Megaptera novaeangliae typically fast for several months in low-latitude breeding areas. Here we report on persistent feeding events during 5 wintering seasons between 2013 and 2020 in a known upwelling region of Banderas Bay of the mainland Mexico breeding area. In total, there were 76 unique feeding events documented (group size = 1 to ~100 individuals), involving 201 photo-identified whales, of which 18 were documented feeding in multiple years. The most prolific years of documented feeding in 2017 and 2018 (based on number of reports/individuals photo-identified feeding) followed the strongest marine heatwave ever recorded in the North Pacific. Whales documented feeding in Banderas Bay had significantly shorter mean sighting histories (2.3 yr) than a non-feeding sample (8.7 yr) and were reported to be of small size, suggesting they were predominantly younger whales. Most high-latitude recaptures of Banderas Bay feeding whales were in more northern North Pacific feeding grounds (50.8% were resighted in Russia, Alaska, and northern British Colombia, Canada). A binomial general linear model revealed a significant relationship between the probability of whales feeding in Banderas Bay and sea surface temperature (SST). Specifically, feeding consistently occurred in years of lower than average winter SST (<25°C), associated with La Niña years of the El Niño Southern Oscillation (ENSO). We conclude that feeding of humpback whales is now a predictable occurrence in the upwelling region of Banderas Bay in years that ENSO fluctuations lead to lower regional SST. The magnitude of several years of low-latitude feeding events reported here was likely influenced by climate change induced marine heatwaves that occurred during the study period.
... The diel pattern of organisms within the deep scattering layer is likely to have a significant bearing in turn on the diel cycles of their predators (at several trophic levels), and several species of cetaceans are known to feed on deep scattering layer organisms at night when they are closer to the surface (Mateu et al. 2015). Within the Arabian Seas region, lanternfish and krill are described foods for Bryde's, blue and humpback whales (Mikhalev 1997(Mikhalev , 2000, but dietary data are missing for most other regional species. However, it seems very probable that lanternfish at least are a significant prey item for several species (e.g. ...
... Based on genetic analyses completed to date, it has been estimated that the Arabian humpback whale population has been reproductively isolated from other populations for approximately 70,000 years . The geographical distribution of the population is poorly known but extends to the Iranian coast of the Sea of Oman in the north (Braulik et al. 2010a), into the Gulf in the west Baldwin 2003;Dakhteh et al. 2017;Mikhalev 1997;Robineau 1998) the waters of Pakistan, Western India and possibly Sri Lanka in the east (Van Beneden 1887;Mikhalev 1997;Baldwin 2003;Gore et al. 2012), as well as the Gulf of Aden (Mikhalev 1997;Slijper et al. 1964). It is unknown whether humpback whales sighted in the northern Red Sea (Notarbartolo di Sciara et al. 2017) belong to the Arabian Sea population or whether they belong to a southern hemisphere population that spends the reproductive season in tropical and temperate waters of the Western Indian Ocean. ...
... Based on genetic analyses completed to date, it has been estimated that the Arabian humpback whale population has been reproductively isolated from other populations for approximately 70,000 years . The geographical distribution of the population is poorly known but extends to the Iranian coast of the Sea of Oman in the north (Braulik et al. 2010a), into the Gulf in the west Baldwin 2003;Dakhteh et al. 2017;Mikhalev 1997;Robineau 1998) the waters of Pakistan, Western India and possibly Sri Lanka in the east (Van Beneden 1887;Mikhalev 1997;Baldwin 2003;Gore et al. 2012), as well as the Gulf of Aden (Mikhalev 1997;Slijper et al. 1964). It is unknown whether humpback whales sighted in the northern Red Sea (Notarbartolo di Sciara et al. 2017) belong to the Arabian Sea population or whether they belong to a southern hemisphere population that spends the reproductive season in tropical and temperate waters of the Western Indian Ocean. ...
The marine mammal fauna found in the waters surrounding the Arabian Peninsula includes 24 species belonging to two Orders: Cetartiodactyla (Bryde’s whale, blue whale, Omura’s whale, humpback whale, sperm whale, dwarf and possibly pygmy sperm whale, Cuvier’s beaked whale, Indo-Pacific common dolphin, pygmy killer whale, short-finned pilot whale, Risso’s dolphin, killer whale, melon-headed whale, false killer whale, Indian Ocean humpback dolphin, pantropical spotted dolphin, striped dolphin, spinner dolphin, rough-toothed dolphin, Indo-Pacific bottlenose dolphin, common bottlenose dolphin, Indo-Pacific finless porpoise), and Sirenia (dugong). The knowledge of the conservation status of marine mammal populations in the Arabian seas region is still poor, due to the low density of local research and monitoring efforts, making it very difficult to compare the current condition of the region’s marine mammals with that of conspecifics from other parts of the world. Anthropogenic pressure factors impacting on Arabian seas marine mammals include noise produced by seismic exploration, disturbance from poorly regulated or unregulated whale or dolphin watching operations, disturbance from vessel traffic and connected noise, ship strikes, direct takes, bycatch in fishery operations, pollution, habitat degradation caused by coastal development, extensive overfishing and harmful algal blooms. The dearth of information about the ecology of marine mammals from the Arabian region results in our enduring inability to understand where conservation action is most urgent.
... Arabian Humpback Whale (Megaptera novaeangliae indica) mother and her juvenile swimming near-shore off the Dubai Offshore Sailing Club in Dubai- The humpback whale has long been considered a rare straggler into the Arabian/Persian Gulf, however new evidence contradicts this concept. Published and new records for the occurrence of Megaptera novaeangliae Borowski, 1781, was for the Introduction An unique, because non-migrating, population of humpback whales Megaptera novaeangliae inhabits year-round the northern Arabian Sea, including the Gulf of Oman (Baldwin and Salm, 1994;Baldwin, 1998;Baldwin et al., 1999;Mikhalev, 1997;Minton et al., 2011;Pomilla et al., 2014). The strong upwelling off Oman allows the whales to feed locally and forgo annual migrations (Papastavrou and Van Waerebeek, 1998). ...
... P < 0.01 for all comparisons). The distributional boundaries of that population are poorly known, but extend to the Irani coast in the north (Braulik et al., 2010;Owfi et al., 2016), at least to Pakistan in the northeast (Van Beneden, 1887;Mikhalev, 1997), and to the Gulf of Aden (Mikhalev, 1997;Slijper et al., 1964) in the Southwest. Based on a working document presented to the IWC Scientific Committee (Dakhteh et al., 2017), we here critically review the long presumed rare occurrence of humpback whales in the Arabian Gulf and suggest possible implications for management (Dakhteh et al., September 2017 In the core distribution area, off the coast of the Sultanate of Oman, humpback whales seem to be concentrated off the Island of Masirah, Gulf of Masirah, Halaniyat Islands and Kuria Muria Bay in the Arabian Sea, considering that greatest numbers of records are from these areas (Baldwin et al., 1999;Minton et al., 2011). ...
... P < 0.01 for all comparisons). The distributional boundaries of that population are poorly known, but extend to the Irani coast in the north (Braulik et al., 2010;Owfi et al., 2016), at least to Pakistan in the northeast (Van Beneden, 1887;Mikhalev, 1997), and to the Gulf of Aden (Mikhalev, 1997;Slijper et al., 1964) in the Southwest. Based on a working document presented to the IWC Scientific Committee (Dakhteh et al., 2017), we here critically review the long presumed rare occurrence of humpback whales in the Arabian Gulf and suggest possible implications for management (Dakhteh et al., September 2017 In the core distribution area, off the coast of the Sultanate of Oman, humpback whales seem to be concentrated off the Island of Masirah, Gulf of Masirah, Halaniyat Islands and Kuria Muria Bay in the Arabian Sea, considering that greatest numbers of records are from these areas (Baldwin et al., 1999;Minton et al., 2011). ...
On Saturday 07.10,2017, two Arabian Humpback Whales(Megaptera novaeangliae indica Gervais, 1883) mother and juvenile were live-sighted in the Sea of Dubai-Jumeirah, near-shore off the Dubai Offshore Sailing Club, between 13.35 – 13.45 hours. The video-recorded sighting was recorded in the Facebook page of the UAE Dolphin Project. This was the First Live-Sighting Record of the Arabian Humpback Whale in the Sea of Dubai.
Reference: Khalaf-Prinz Sakerfalke von Jaffa, Prof. Dr. Sc. Norman Ali Bassam Ali Taher Mohammad Ahmad Mostafa (November 2017). First Sighting Record of the Arabian Humpback Whale (Megaptera novaeangliae indica Gervais, 1883) in the Sea of Dubai, United Arab Emirates, Arabian Gulf. Gazelle: The Palestinian Biological Bulletin. ISSN 0178 – 6288. Volume 35, Number 155, November 2017, pp. 16-50. Published by Prof. Dr. Norman Ali Khalaf Department for Environmental Research and Media, National Research Center, University of Palestine, Gaza, State of Palestine.http://marine-life-uae-2.webs.com/arabian-humpback-whale
... Therefore, most of the available information comes from opportunistic or bycatching records from public online resources. Collating all published information in newspapers, local and international academic journals (Roberts, 1977;De Silva, 1987), from soviet whaling (Mikhalev, 1997(Mikhalev, , 2000, and historical records published by Pilleri and Gihr (1972a, b), revealed that the coastal area of Pakistan carry a considerable diversity of cetaceans. The data gaps around cetacean diversity, distribution, and abundance from the Northern Indian Ocean (Kumarran, 2002(Kumarran, , 2009) specifically related to threatened species from the coastal area of Pakistan appeared a primary barrier in formulating a practical and robust national policy for conservation of biodiversity (Rizvi et al., 1995). ...
... Three subspecies of blue whales were widely recognized globally, however, the species in Northern Indian Ocean appeared to be a distinct population or additional subspecies of pygmy blue whale (Blyth, 1859;Branch et al., 2007b;Yochem and Leatherwood, 1985). During earlier 1960s, the Soviet whaling hunted nearly 1,294 blue whales from the Arabian Sea (Mikhalev, 1997(Mikhalev, , 2000 and 31 catches were made along the India and Pakistan borders (Mikhalev, 2000). The population of blue whale has increased and recently recovered (Branch et al., 2007b) around the world. ...
... Therefore, most of the available information comes from opportunistic or bycatching records from public online resources. Collating all published information in newspapers, local and international academic journals (Roberts, 1977;De Silva, 1987), from soviet whaling (Mikhalev, 1997(Mikhalev, , 2000, and historical records published by Pilleri and Gihr (1972a, b), revealed that the coastal area of Pakistan carry a considerable diversity of cetaceans. The data gaps around cetacean diversity, distribution, and abundance from the Northern Indian Ocean (Kumarran, 2002(Kumarran, , 2009) specifically related to threatened species from the coastal area of Pakistan appeared a primary barrier in formulating a practical and robust national policy for conservation of biodiversity (Rizvi et al., 1995). ...
... Three subspecies of blue whales were widely recognized globally, however, the species in Northern Indian Ocean appeared to be a distinct population or additional subspecies of pygmy blue whale (Blyth, 1859;Branch et al., 2007b;Yochem and Leatherwood, 1985). During earlier 1960s, the Soviet whaling hunted nearly 1,294 blue whales from the Arabian Sea (Mikhalev, 1997(Mikhalev, , 2000 and 31 catches were made along the India and Pakistan borders (Mikhalev, 2000). The population of blue whale has increased and recently recovered (Branch et al., 2007b) around the world. ...
... They are designated as "Endangered" on the IUCN Red List (Minton et al. 2008) due to their low abundance (82 animals estimated for the subregion off the coast of Oman, 95% CI: 60-111), isolation from other neighboring populations, and mounting threats in their range (Minton et al. 2008(Minton et al. , 2011. The population was significantly depleted by Soviet whaling operations, which illegally harvested 242 ASHW from this region in the 1960s (Mikhalev 1997). Compared to the scale of global industrial whaling activities that killed approximately three million whales (Rocha et al. 2015), a catch of 242 whales seems relatively small. ...
... Compared to the scale of global industrial whaling activities that killed approximately three million whales (Rocha et al. 2015), a catch of 242 whales seems relatively small. However, the scientists on board the Soviet whaling vessels estimated that they took ~ 60% of the ASHW present in the Arabian Sea, and that the low catch from this non-migratory population likely indicates ASHW had naturally low abundance prior to whaling (Mikhalev 1997). ASHW have a significantly lower genetic diversity compared to other southern hemisphere humpback whale populations, a pattern consistent with ancient and recent genetic bottlenecks (Pomilla et al. 2014). ...
Arabian Sea humpback whales (Megaptera novaeangliae; ASHW) are listed as Endangered by the International Union for the Conservation of Nature (IUCN). The long-term presence and increased prevalence of tattoo skin disease-like (TSD-L) dermatopathy is a concern for this small non-migratory population. Characterized by irregular or rounded, light gray or whitish cutaneous lesions, this condition resembles tattoo skin disease, caused by cetacean poxviruses. Although the etiological agent and pathogenicity of TSD-L dermatopathy are unknown, previous studies have suggested that it is an indicator of population health. Until now, disease diagnosis had been based on photographs collected from survey vessels. In this study, we describe a novel method of identifying and quantifying TSD-L lesions in ASHW, using drone aerial photography. Aerial photos of the entire dorsum were selected for 18 whales with the same criteria applied for assessing body condition to quantify the percent coverage for each individual. We effectively diagnosed this condition from close-up aerial photos or good-quality photos of the lateral body surface taken from the research vessel in 13 whales. TSD-L dermatopathy coverage ranged from 2.34 to 57.00% and measurements were consistent between photographs of the same whale (SD = 1.86%). Drone aerial photography provided a useful and complimentary approach to identify and quantify TSD-L lesions. Continued monitoring using this non-invasive method should be combined with other population and health monitoring tools to increase our understanding of the characteristics and epidemiology of this condition, and to provide critical information for conservation efforts that ensure the recovery of this endangered population.
... Humpback whales in the Arabian Sea comprise the only known population that does not undertake the longrange latitudinal seasonal migrations typical of the species. High primary productivity associated with seasonal upwelling ensures that Arabian Sea humpback whales (ASHW) can find abundant prey as well as the tropical conditions associated with mating, calving and nursing (Reeves et al., 1991;Mikhalev, 1997;Papastavrou and Van Waerebeek, 1997;Minton et al., 2011). Illegal Soviet whaling in the mid-1960's resulted in the killing of 242 humpback whales off the coasts of Oman, Pakistan and India, and scientists on board the vessels estimated that they had taken 60% of the whales in the population (Mikhalev, 1997). ...
... High primary productivity associated with seasonal upwelling ensures that Arabian Sea humpback whales (ASHW) can find abundant prey as well as the tropical conditions associated with mating, calving and nursing (Reeves et al., 1991;Mikhalev, 1997;Papastavrou and Van Waerebeek, 1997;Minton et al., 2011). Illegal Soviet whaling in the mid-1960's resulted in the killing of 242 humpback whales off the coasts of Oman, Pakistan and India, and scientists on board the vessels estimated that they had taken 60% of the whales in the population (Mikhalev, 1997). Of the likely range countries for this subpopulation, dedicated vessel-based surveys have, until recently, been limited to the coastal waters of Oman. ...
The sub‐population of humpback whales inhabiting the Arabian Sea is a small and genetically distinct population that remains in low latitudes year‐round. Designated as Endangered on the IUCN Red list of Threatened Species, the sub‐population faces a number of threats throughout its range, including entanglement in fishing gear, ship strikes, disease and habitat degradation. Research conducted primarily off the coast of Sultanate of Oman over the past 20 years has contributed to understanding the population’s distribution, abundance, and conservation status. However, information on the population’s health and specific threats is limited. This study examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites, ectoparasites, and human‐induced scars and wounds. Tattoo skin disease‐like lesions were detected in 41% of 93 whales, with a roughly equal distribution between males and females. Prevalence of the disease was significantly higher in 2012–2018 (51.7%) than in 2000–2011 (27.6%). Killer whale tooth rakes were detected on the ventral surface of the tail flukes of 12% (95% CI 4.5–18%) of 77 individuals. Roughly two thirds (66.6%: 95% CI 52–80%) of the 42 individuals represented by good quality photographs of the caudal peduncle region at the fluke insertion bore scarring patterns consistent with entanglement in fishing gear. At least two individuals showed severe injuries or deformations likely caused by interactions with fishing gear. Six individuals had injuries consistent with vessel strikes. Documented entanglement events from Oman and Pakistan involved large‐mesh nylon gillnets, known to be used extensively throughout the Arabian Sea. These findings indicate an urgent need to design effective measures for the management and mitigation of threats, and to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions.
... Unlike all other humpback populations, the animals in the Arabian Sea comprise an extremely small population of year-round residents. They follow a Northern Hemisphere breeding cycle (Mikhalev 1997), but have no physical access to high-latitude feeding areas: Biannual periods of monsoon-driven productivity allow them to remain in the Arabian Sea and feed throughout the year (Minton et al. 2011). Therefore, they do not undertake the latitudinal migrations typical of other populations. ...
... Therefore, they do not undertake the latitudinal migrations typical of other populations. This population was subjected to intensive illegal Soviet whaling in the 1960s that reduced a population that was thought to be already small in size, on the order of hundreds of animals (Mikhalev 1997); current estimates suggest the remaining population could be less than 100 animals (Minton et al. 2011) and has significantly lower genetic diversity than Southern Hemisphere populations (Pomilla et al. 2014). What can studies of an isolated, non-migratory population of humpback whales tell us about the mechanisms and underlying drivers for song complexity and change? ...
It has been fifty years since Payne and McVay’s seminal publication on the strange and beautiful sounds of the humpback whaleHumpback whale (Megaptera novaeangliaeMegaptera novaeangliae), the study which inspired decades of research into their complex, underwater acoustic world. In the subsequent five decades, there probably have been more research projects and publications on humpback whaleHumpback whale song than on the vocal behavior of any other baleen whale. What makes humpback song so unique? What have we learned? What questions remain? With this chapter, we explore these questions with an eye toward the overarching theme of studies that address proximate mechanisms (the “how do humpback whalesHumpback whaledo this?” questions) versus those that inquire about ultimateProximate vs ultimate causes (the “why do humpback whalesHumpback whaledo this?” questions). We draw a distinction between studies that focus on singing behavior, versus those that use song as a proxy to investigate other biological processes. We take the reader through a historical review of the literature, ending with a series of observations about the unanswered questions intended to provoke new ideas and new lines of inquiry. Through this exploration, we hope to synthesize a global body of research to identify common themes and probe the lingering gaps in our understandings of humpback whaleHumpback whale song.
... Mother-calf pairs were recorded during both seasons. The occurrence of calves in December and February is consistent with the known northern-winter breeding of ASHW, with first calving in December (Mikhalev, 1997). Minton et al. (2011) recorded unexpectedly low numbers of females with calves off Oman in February; the data compiled here suggest that at least some of the ASHW population uses the southeast Arabian Sea as a breeding ground at that time. ...
... Range contraction due to population decline as a result of overfishing has been documented in other marine megafauna (Burgess et al., 2017;Worm and Tittensor, 2011;Yan et al., 2021). ASHW were depleted by Soviet whaling in the 1960s (Mikhalev, 1997), and the population has never recovered, with entanglement in fishing gear (particularly pelagic gillnets) being implicated as a continuing cause of injury and mortality (Anderson et al., 2020;Minton et al., 2011Minton et al., , 2020Pomilla et al., 2014;Sutaria et al., 2015). The ASHW population is listed as Endangered by IUCN (Minton et al., 2008) although there is a recommendation for that listing to be revised to Critically Endangered (Pomilla et al., 2014). ...
In the central Indian Ocean, humpback whales ( Megaptera novaeangliae) are rare. Records from southern India, Sri Lanka, Maldives and the Chagos Archipelago (n = 68) were compiled and show a bimodal pattern of seasonal occurrence. Those occurring during the northern winter (December to March) are known from other studies to belong to the Arabian Sea humpback whale population. There have been no humpback whales recorded in Maldives during the northern winter since 2002, suggesting a possible range contraction for the Arabian Sea humpback whale population. Humpback whales occurring during the southern winter (June to October) are assumed to belong to the southwest Indian Ocean population (IWC breeding stock C). In this case, numbers of opportunistic sightings are increasing and the population appears to be spreading northwards as it recovers from commercial whaling, with several recent southern winter records from as far north as 5°N in northern Maldives and southern Sri Lanka. For this southern hemisphere population, calves are first seen in August, with numbers of calves increasing in September and October. For both populations, interactions with regional fisheries, particularly pelagic gillnetting, may be a major cause of mortality.
... Humpback whales in the Arabian Sea are believed to belong to a resident stock (Reeves et al., 1991;Mikhalev, 1997;Papastavrou and Van Waerebeek, 1997;Minton et al., 2002;Rosenbaum et al., 2002). They appear to be rare in Maldivian waters, with only a single sighting by the author. ...
... Humpback whales were possibly not uncommon in the area of the Maldives prior to the mid-1960s. At that time (mostly in November 1966) Soviet whalers killed at least 242 humpback whales in the Arabian Sea (Mikhalev, 1997;2000). Large numbers of blue, Bryde's and sperm whales were taken at the same time, many of them in the vicinity of the Maldives (Mikhalev, 1996;2000). ...
Cetaceans observed in Maldivian waters were recorded during the period August 1990 to June 2002, from both vessels-of-opportunity and dedicated cetacean-watching cruises. A total of 1,829 cetacean sightings were recorded during 535 days at sea (equivalent to 261
standardised days). There were 83 multispecies sightings, plus a further 58 sightings without associated effort data and 129 strandings were recorded by the author and others, making a total of 2,108 cetacean records. In all, 20 different species were positively identified from sightings. Spinner dolphins were the most abundant species seen, accounting for 35% of sightings and 53% of numbers. This species showed a clear diurnal pattern of behaviour, with many schools entering the atolls in the early morning, and leaving in the late afternoon. Spinner dolphins regularly occurred with pantropical spotted dolphins and both species associated with yellowfin tuna. Bryde’s whales also
associated with yellowfin tuna and appeared to be most common in Maldivian waters during El Niño Southern Oscillation events. Blue whales were only recorded during November to April. Dwarf sperm whales were especially difficult to locate in rough weather but relatively common, making up one sixth of all sightings in flat-calm conditions. Melon-headed whales were particularly common in the south of the
Maldives, but rare in the centre and north. Other species recorded were humpback whale, sperm whale, rough-toothed dolphin, Risso’s dolphin, bottlenose dolphin, striped dolphin, Fraser’s dolphin, pygmy killer whale, false killer whale, killer whale, short-finned pilot whale, Blainville’s beaked whale, Longman’s beaked whale and Cuvier’s beaked whale.
... Humpback whales (Megaptera novaeangliae) inhabit all major oceans and have adapted to diverse ecosystems, including polar and subpolar ecosystems mainly to feed during the summer months, and equatorial ecosystems almost exclusively to breed and calve throughout the winter months (e.g. [1][2][3][4][5]). To reach the most productive feeding areas, humpback whales undertake one of the longest mammalian migrations, stretching between their low-latitude breeding grounds and mid-to highlatitude feeding grounds [6,7]. ...
... To reach the most productive feeding areas, humpback whales undertake one of the longest mammalian migrations, stretching between their low-latitude breeding grounds and mid-to highlatitude feeding grounds [6,7]. As in other baleen whale species, migratory behaviour, in humpback whales, is characterized by population-specific spatio-temporal patterns, but is also flexible in terms of destinations and timing, including the omission or delay of migration or the spatial adaptation of migration routes [3,[7][8][9][10]. Less extreme migratory deviations are very common in many baleen whale populations worldwide. ...
Southern Hemisphere humpback whales ( Megaptera novaeangliae ) inhabit a wide variety of ecosystems including both low- and high-latitude areas. Understanding the habitat selection of humpback whale populations is key for humpback whale stock management and general ecosystem management. In the Atlantic sector of the Southern Ocean ( ASSO ), the investigation of baleen whale distribution by sighting surveys is temporally restricted to the austral summer. The implementation of autonomous passive acoustic monitoring, in turn, allows the study of vocal baleen whales year-round. This study describes the results of analysing passive acoustic data spanning 12 recording positions throughout the ASSO applying a combination of automatic and manual analysis methods to register humpback whale acoustic activity. Humpback whales were present at nine recording positions with higher acoustic activities towards lower latitudes and the eastern and western edges of the ASSO . During all months, except December (the month with the fewest recordings), humpback whale acoustic activity was registered in the ASSO . The acoustic presence of humpback whales at various locations in the ASSO confirms previous observations that part of the population remains in high-latitude waters beyond austral summer, presumably to feed. The spatial and temporal extent of humpback whale presence in the ASSO suggests that this area may be used by multiple humpback whale breeding populations as a feeding ground.
... A very small population size, in combination with the lack of recording effort in the Arabian Sea, may explain why this songtype has gone undetected for so long. Arabian Sea humpback whales are a genetically distinct and highly diverged population (Pomilla et al. 2014) that were also severely impacted by Soviet whaling operations (Mikhalev 1997). They currently are estimated to have a very low population abundance, with likely fewer than 100 animals and a point estimate of 82 individuals (95% CI 60−111), leading to their classification as Endangered according to the IUCN Red List of Threatened Species (Minton et al. 2008(Minton et al. , 2011. ...
... They currently are estimated to have a very low population abundance, with likely fewer than 100 animals and a point estimate of 82 individuals (95% CI 60−111), leading to their classification as Endangered according to the IUCN Red List of Threatened Species (Minton et al. 2008(Minton et al. , 2011. The Soviet whalers took 242 humpback whales off the coasts of Oman, Pakistan, and India, of a population they estimated to be on the order of 400 individuals (Mikhalev 1997). Given the size of the blue whale catch, the source population was clearly much larger than the humpback whale population; however, it seems feasible, if not likely, that the blue whale population was reduced to an equally small fraction of the original population size, with total numbers of catches decreasing from 1060, during the 1963/64 and 1964/1965 expeditions, to 234 during the 1965/66 and 1966/67 expeditions (Mikhalev 1996(Mikhalev , 2000. ...
Blue whales Balaenoptera musculus in the Indian Ocean (IO) are currently thought to represent 2 or 3 subspecies ( B. m. intermedia, B. m. brevicauda , B. m. indica ), and believed to be structured into 4 populations, each with a diagnostic song-type. Here we describe a previously unreported song-type that implies the probable existence of a population that has been undetected or conflated with another population. The novel song-type was recorded off Oman in the northern IO/Arabian Sea, off the western Chagos Archipelago in the equatorial central IO, and off Madagascar in the southwestern IO. As this is the only blue whale song that has been identified in the western Arabian Sea, we label it the ‘Northwest Indian Ocean’ song-type to distinguish it from other regional song-types. Spatiotemporal variation suggested a distribution west of 70°E, with potential affinity for the northern IO/Arabian Sea, and only minor presence in the southwestern IO. Timing of presence off Oman suggested that intensive illegal Soviet whaling that took 1294 blue whales in the 1960s likely targeted this population, as opposed to the more widely distributed ‘Sri Lanka’ acoustic population as previously assumed. Based upon geographic distribution and potential aseasonal reproduction found in the Soviet catch data, we suggest that if there is a northern IO subspecies ( B. m. indica ), it is likely this population. Moreover, the potentially restricted range, intensive historic whaling, and the fact that the song-type has been previously undetected, suggests a small population that is in critical need of status assessment and conservation action.
... The population of humpback whales in the Arabian Sea does not undertake the same long-range seasonal migrations typical of the species, a characteristic unique among humpback whale populations. High primary productivity associated with seasonal upwelling in the Arabian Sea ensures that Arabian Sea humpback whales (ASHW) can find abundant prey as well as the tropical conditions associated with mating, calving and nursing (Reeves et al., 1991;Mikhalev, 1997;Papastavrou and Van Waerebeek, 1997;Minton et al., 2011). Illegal Soviet whaling in the mid-1960's resulted in the killing of 242 humpback whales off the coasts of Oman, Pakistan and India, and scientists on board the soviet vessels estimated that they had taken 60% of the whales in the region (Mikhalev, 1997). ...
... High primary productivity associated with seasonal upwelling in the Arabian Sea ensures that Arabian Sea humpback whales (ASHW) can find abundant prey as well as the tropical conditions associated with mating, calving and nursing (Reeves et al., 1991;Mikhalev, 1997;Papastavrou and Van Waerebeek, 1997;Minton et al., 2011). Illegal Soviet whaling in the mid-1960's resulted in the killing of 242 humpback whales off the coasts of Oman, Pakistan and India, and scientists on board the soviet vessels estimated that they had taken 60% of the whales in the region (Mikhalev, 1997). Research conducted off the coast of Oman between 2000 and 2017 has confirmed that the population is genetically distinct and isolated (Pomilla and Amaral et al. 2014), and that fewer than 100 individuals are likely to remain in Omani waters , factors that contributed to an Endangered IUCN Red List status (Minton et al., 2008). ...
Arabian Sea humpback whales have been a subject of conservation concern in the IWC since 1997. Research conducted primarily off the coast of Oman has contributed to understanding the population’s distribution, abundance, and conservation status, whilst information on the population’s health and specific threats is more limited. This study
examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites and human-induced scarring or injury to individuals. Tattoo-like skin disease was detected in 43.4% of 83 adult whales, with a roughly equal distribution between males and females. The prevalence of the
disease was significantly higher in 2012-2018 (51.7%) than in 2000-2011 (24.1%). The lesions persisted for two to 14 years in 10 whales and progressed in prevalence and percentage of body cover in six of them. Killer whale tooth rakes were detected in 12% (95% CI 4.5-18%) of individuals based on examination of photographs showing the ventral
surface of tail flukes (n=77), but no cookie cutter shark wounds were detected on any body parts of any of the whales examined. Roughly two thirds (66.6%: 95% CI 52-80%) of individuals represented by good quality photos of the caudal peduncle region (n=42) bore scarring patterns considered likely to be associated with entanglement in fishing gear, with no significant differences in entanglement scarring rates between males and females. Four individuals bore injuries consistent with vessel strikes and at least two individuals showed severe injuries and deformations likely to have been caused by interactions with vessels and/or fishing gear. Five documented entanglement events from Oman and Pakistan involved large-mesh nylon gillnets, which are known to be used extensively throughout the Arabian Sea. In light of this population’s endangered status, these findings indicate an urgent need to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions, aimed toward designing effective conservation strategies to mitigate known threats.
... Also, the tracking data collected during the warm season was outside the mating and calving season for this species [85][86][87]. Similar behavior has been documented for other resident fin whale populations such as the Mediterranean population, which primarily exhibits ARS behavior throughout the year as they move between potential feeding areas [31,88,89]. These cases are not unique among balaenopterids, as there are other non-migratory populations found in the tropics, subtropics, and enclosed seas, such as Bryde's whales [76] and one distinct population segment of humpback whales (Megaptera novaeangliae) in the Arabian Sea [88], which is able to subsist on year-round productivity. ...
... Similar behavior has been documented for other resident fin whale populations such as the Mediterranean population, which primarily exhibits ARS behavior throughout the year as they move between potential feeding areas [31,88,89]. These cases are not unique among balaenopterids, as there are other non-migratory populations found in the tropics, subtropics, and enclosed seas, such as Bryde's whales [76] and one distinct population segment of humpback whales (Megaptera novaeangliae) in the Arabian Sea [88], which is able to subsist on year-round productivity. ...
Fin whales (Balaenoptera physalus) have a global distribution, but the population inhabiting the Gulf of California (GoC) is thought to be geographically and genetically isolated. However, their distribution and movements are poorly known. The goal of this study was to describe fin whale movements for the first time from 11 Argos satellite tags deployed in the southwest GoC in March 2001. A Bayesian Switching State-Space Model was applied to obtain improved locations and to characterize movement behavior as either “area-restricted searching” (indicative of patch residence, ARS) or “transiting” (indicative of moving between patches). Model performance was assessed with convergence diagnostics and by examining the distribution of the deviance and the behavioral parameters from Markov Chain Monte Carlo models. ARS was the predominant mode behavior 83% of the time during both the cool (December-May) and warm seasons (June-November), with slower travel speeds (mean = 0.84 km/h) than during transiting mode (mean = 3.38 km/h). We suggest ARS mode indicates either foraging activities (year around) or reproductive activities during the winter (cool season). We tagged during the cool season, when the whales were located in the Loreto-La Paz Corridor in the southwestern GoC, close to the shoreline. As the season progressed, individuals moved northward to the Midriff Islands and the upper gulf for the warm season, much farther from shore. One tag lasted long enough to document a whale’s return to Loreto the following cool season. One whale that was originally of undetermined sex, was tagged in the Bay of La Paz and was photographed 10 years later with a calf in the nearby San Jose Channel, suggesting seasonal site fidelity. The tagged whales moved along the western GoC to the upper gulf seasonally and did not transit to the eastern GoC south of the Midriff Islands. No tagged whales left the GoC, providing supporting evidence that these fin whales are a resident population.
... The location in Pakistan's EEZ (Figure 1) is oceanic and in the relative vicinity (ca. 90 km) of the 'Swatch' or Indus undersea Canyon (Kolla & Coumes, 1985), which along with its surrounding deep waters are not only known as a very important fishing ground for tuna and other large pelagic fishes, but also as an important habitat for deep water fish species, cetaceans, and other large marine vertebrates (e.g., Ahmed, 1985;Mikhalev, 1997;Kiani et al., 2013). The location off Iran is also a biodiverse and important fishing ground, mainly because of Arabian Sea upwelling currents (Ershadifar et al., 2023). ...
... Baleen whales undertake seasonal migrations to feed, mate, and give birth. The distances of these migrations and the extent to which breeding and feeding areas are separated from each other vary greatly across species, sometimes even across populations (e.g., nonmigratory Arabian sea humpback whales, Megaptera novaeangliae : Mikhalev 1997). While some of the largest lunge feeders (rorquals), blue and fin whales (Balaenoptera musculus and B. physalus), appear to breed dispersed across unobserved offshore areas (Simon et al. 2010;Sears et al. 2013), other baleen whales aggregate on distinct breeding grounds (e.g., humpback whale; gray whale, Eschrichtius robustus; southern right whales, Eubalaena australis). ...
How the underlying forces of sexual selection impact reproductive tactics including elaborate acoustic displays in cetaceans remains poorly understood. Here, I combined 26 years (1995-2020) of photo-identification, behavioural, (epi)genetic, and endocrine data from an endangered population of humpback whales (New Caledonia), to explore male reproductive success, age, physiology, and population dynamics over almost a third of the lifespan of a humpback whale. First, I conducted a paternity analysis on 177 known mother-offspring pairs and confirmed previous findings of low variation in reproductive success in male humpback whales. Second, epigenetic age estimates of 485 males revealed a left-skewed population age structure in the first half of the study period that became more balanced in the second half. Further, older males (> 23 years) more often engaged in certain reproductive tactics (singing and escorting) and were more successful in siring offspring once the population age structure stabilised, suggesting reproductive tactics and reproductive success in male humpback whales may be age-dependent. Third, using enzyme immunoassays on 457 blubber samples, I observed a seasonal decline in male testosterone in the population over the breeding season. Testosterone levels appeared highest during puberty, then decreased and levelled off at the onset of maturity, yet were highly variable at any point during the breeding season and across males of all ages. Lastly, I investigated the influence of genetic diversity at the major histocompatibility complex (MHC) class I and class IIa (DQB and DRB-a) on patterns of male reproductive success in humpback whales. Mating pairs shared fewer alleles than expected under random mating at MHC class I and IIa, thus, providing evidence of an MHC-mediated female mate choice in humpback whales. This thesis provides novel, critical insights into the evolutionary consequences of commercial whaling on the demography, patterns of reproduction and sexual selection of exploited populations of baleen whales.
... Most baleen whales undertake seasonal migrations to feed, mate, and give birth. The distances of these migrations and the extent to which breeding and feeding areas are separated from each other vary greatly across species, sometimes even across populations (e.g., non-migratory Arabian sea humpback whales, Megaptera novaeangliae : Mikhalev 1997). While some of the largest lunge feeders (rorquals), blue and fin whales (Balaenoptera musculus and B. physalus), appear to breed dispersed across unobserved offshore areas (Simon et al. 2010;Sears et al. 2013), other baleen whales aggregate on distinct breeding grounds (e.g., humpback whale; gray whale, Eschrichtius robustus; southern right whales, Eubalaena australis). ...
While a variety of reproductive tactics are readily witnessed in odontocetes, such behaviors can be far more elusive in baleen whales and in some cases are yet to be observed. This leads researchers to study the reproductive behaviors in mysticetes using a variety of research methods which have improved greatly in recent years. Genetics and genomics tools can provide valuable information on maternity, paternity, age, diversity, and kinship, while acoustic tools can provide new insights into the function of sexual displays such as song. In this chapter, we explore what is known about reproductive strategies and tactics of baleen whales, with a particular focus on the comparatively well-studied right whales ( Eubalaena spp.) and humpback whale ( Megaptera novaeangliae ). Finally, we showcase that by integrating multiple data types, we can explore the interactions between anatomy, physiology, reproductive success, age, population dynamics, and acoustic displays to better understand the mating systems of baleen whales.
... Most baleen whale populations undertake long-distance migrations from polar feeding areas to tropical breeding grounds (Chittleborough 1965;Dawbin 1966;Stone et al. 1990;Mikhalev 1997;Palsbøll et al. 1997;Jenner et al. 2001). This movement enables populations to exploit seasonally favourable habitats (Clapham 1996(Clapham , 2001Pallin et al. 2023). ...
Context
The east and west coasts of Australia form the breeding grounds for two of the world’s largest and fastest-growing populations of humpback whales (Megaptera novaeangliae). These populations show differences in mean lipid content, fatty acid profiles, and stable isotope values.
Aims
To determine whether these differences result in variation in nutritional health and physiology between populations, we quantified and compared the morphology, body condition and energetic requirements between the two populations.
Methods
We used unmanned aerial vehicles to measure body morphometrics (residual of body volume vs length) of humpback whales from May to November in 2017, 2020 and 2021.
Key results
Morphometric measurements were obtained from 973 humpback whales (119 calves, 249 juveniles, 486 adults, and 119 lactating females). Results showed that the two populations did not differ significantly in their morphology. The average body condition was significantly different for sexually mature reproductive classes, with adults and lactating females on the west coast having a lower body condition, by an average of 7.7 and 11.1 percentage points below the east coast population respectively. All reproductive classes, with the exception of calves followed a similar pattern in body condition loss through the breeding season. Calves on the east coast exhibited a curvilinear relationship with days post-partum, with early and late-migrating calves being in poorer body condition than were those migrating mid-season. In contrast, west coast calves did not significantly change their condition through the breeding season.
Conclusions
The poorer body condition of sexually mature individuals in the west coast population is concerning, given the overall condition loss during a breeding season. This difference could be influenced by variations in sampling time; however, differences in feeding opportunities, climatic regimes and/or environmental variables may influence the ability of one population to acquire similar amounts of energy.
Implications
The difference in body condition between these two humpback whale populations highlighted the need to assess populations individually, so as to develop representative levels that can be used for future conservation monitoring and management.
... On the other hand, their geographical distribution is fairly discrete, and their breeding cycle is 6 months out of phase with those in the southern Indian Ocean (Mikhalev 2000). It is noteworthy that a resident population of humpback whales in the northern Indian Ocean (particularly the Arabian Sea) also has a reproductive cycle shifted by 6 months compared with the Southern Hemisphere (Mikhalev 1997). This stranding information would help the taxonomists to protect the cetaceans along the Bay of Bengal coast and further investigation is necessary for their management interventions. ...
The present paper reports the molecular analysis (CoI) of a female blue whale Balaenoptera musculus (Linnaeus, 1758) of approximately 40 ft in length, stranded on June 29, 2020 at Mandarmani along the West Bengal coast. This is the second record of stranding of blue whale along the coast after 1934. The strandings provides vital information on species life histories, population health and status of marine ecosystems. Since all cetaceans are important from a conservation perspective; precise documentation of their occurrence would provide valuable information about the distribution and migratory nature of different species in the seas around India. A table of blue whales stranded on Indian coasts between 1874 and 2020 has been provided.
... Uniquely, ASHWs do not perform a seasonal migration as other populations do, instead remaining resident in tropical waters throughout the year (Mikhalev, 1997). Along with being geographically isolated and demonstrating behaviour atypical for humpback whales, ASHWs constitute a genetically isolated, discrete population (Pomilla et al., 2014). ...
Arabian Sea humpback whales (Megaptera novaeangliae), listed as "Endangered" on the International Union for Conservation of Nature's Red List, remain resident throughout the year in the waters of the Arabian Sea and constitute a genetically isolated population. In the eastern Arabian Sea, information on humpback whales off the Indian coast has largely been limited to stranding records, local ecological knowledge, and opportunistic visual sighting data. These data, along with information from a long-term study off Oman, suggest that humpback whales migrate across the Arabian Sea into Indian territorial waters from October to March. To study the presence of Arabian Sea humpback whales in Indian waters more comprehensively, passive acoustic monitoring (PAM) was initiated along the west coast of India in 2019. Male humpback whales produce complex songs with a stereotyped structure; these songs are shared within a population, and song patterns are known to evolve progressively over time. In this article, a structural analysis of humpback whale song recorded over four days off the coast of Netrani Island, Karnataka, India, in December 2019 is presented. Time-frequency features of 2,641 individual call units were analysed. Call units had a fundamental frequency bandwidth ranging from 149.98 to 541.65 Hz, with a duration ranging from 1.19 to 5.5 s. The call units were used to identify phrases and themes required to construct the structure of the song, which can potentially help identify the population to which singing individuals belong. This study indicates the need for a long-term PAM program across the Arabian Sea to compare whale songs across the region. Simultaneous recordings over multiple seasons will best assess population connectivity, seasonal occurrence, and movement patterns within and between populations across the Arabian Sea and the Indian Ocean.
... Reproduction in all but the Arabian Sea population of humpback whales (Mikhalev, 1997) is based around an annual migration from high latitude nutritionally productive feeding grounds to low latitude warm breeding grounds on which all but calves-of-the-year fast , although occasional feeding on some breeding grounds has been observed (Gendron, 1993). Humpback whales of both sexes and all age classes migrate between feeding and breeding grounds with migratory timing a function of sex, age class, and reproductive and nutritional condition Straley et al., 1994). ...
Alaskan marine ecosystems are undergoing unprecedented change and species are facing increasingly variable and potentially inhospitable habitats. As top predators, marine mammals serve an important role as sentinels of ecosystem health. With their high site fidelity, abundant numbers, coastal presence and role as a top predator, humpback whales (Megaptera novaeangliae) provide a meaningful
view into current ecosystem conditions and processes. In order to tap into their usefulness as bioindicators the basic physiology of humpback whales needs to be understood. Physiological indices can provide valuable information about fecundity, survival, health and population age structuring which is fundamental to cetacean research and population management. However, such information is often
difficult to obtain from wild cetaceans as they surface infrequently and often live in remote or logistically challenging locations. As such, few methods currently exist for the assessment of physiological parameters of free ranging, large cetaceans. This dissertation paired existing methods of physiological examination with novel approaches in order to better understand the basic physiology and overall health
of humpback whales. Specifically, six enzyme immunoassays were validated for use in humpback whales for progesterone, testosterone, cortisol, corticosterone, aldosterone and DHEA-S, an algorithm termed “Morphometer” was developed to automate the process of measuring and analyzing morphometric measurements, and hormones and body condition metrics were paired to determine whether pregnancy status can be detected from aerial photographs. This project seeks to lay the groundwork for long term monitoring of humpback whales that can provide critical information to managers. By using baseline physiological indices and tools to rapidly analyze these metrics that I developed here, managers and researchers will be able to analyze current and future samples within a longitudinal context and make management decisions based on more accurate biological information for these populations.
... The Distinctive Population Segment in the Arabian Sea did not exhibit significant migrations, as mentionedin the literature [74]. The endangered status of DPS 14 is, however, interpreted to be due the over-whaling performed by the Soviet Union in the 1960s that brought the population to a low viability [75], rather than other problems linked to the relative confinement of the individuals. In all cases, the results tend to support the consistency of the parameter estimates available in the literature, but they do not allow to address the problems of sub-population viability as they were summarized by Bettridge et al. [7]. ...
Whale migrations are poorly understood. Two competing hypotheses dominate the literature: 1. moving between feeding and breeding grounds increases population fitness, 2. migration is driven by dynamic environmental gradients, without consideration of fitness. Other hypotheses invoke communication and learned behaviors. In this article, their migration was investigated with a minimal individual-based model at the scale of the Global Ocean. Our aim is to test if global migration patterns can emerge from only the local, individual perception of environmental change. The humpback whale (Megaptera novaeangliae) meta-population is used as a case study. This species reproduces in 14 zones spread across tropical latitudes. From these breeding areas, humpback whales are observed to move to higher latitudes seasonally, where they feed, storing energy in their blubber, before returning to lower latitudes. For the model, we developed a simplified ethogram that conditions the individual activity. Then trajectories of 420 whales (30 per DPS) were simulated in two oceanic configurations. The first is a homogeneous ocean basin without landmasses and a constant depth of −1000 m. The second configuration used the actual Earth topography and coastlines. Results show that a global migration pattern can emerge from the movements of a set of individuals which perceive their environment only locally and without a pre-determined destination. This emerging property is the conjunction of individual behaviors and the bathymetric configuration of the Earth’s oceanic basins. Topographic constraints also maintain a limited connectivity between the 14 DPSs. An important consequence of invoking a local perception of environmental change is that the predicted routes are loxodromic and not orthodromic. In an ocean without landmasses, ecophysiological processes tended to over-estimate individual weights. With the actual ocean configuration, the excess weight gain was mitigated and also produced increased heterogeneity among the individuals. Developing a model of individual whale dynamics has also highlighted where the understanding of whales’ individual behaviors and population dynamic processes is incomplete. Our new simulation framework is a step toward being able to anticipate migration events and trajectories to minimize negative interactions and could facilitate improved data collection on these movements.
... Arabian Sea population is especially vulnerable. Not only does it live in the midst of an area with very high levels of gillnetting, but also its original population size was probably not large and it was subject to a period of intense whaling by Soviet whaling fleets in the mid-1960s (Mikhalev, 1997). This population has still not recovered and may comprise no more than 100 individuals (Minton et al., 2011). ...
This report reviews information on interactions between cetaceans (whales and
dolphins) and tuna fisheries in the western and central Indian Ocean.
... Recent whaling also occurred in the Arabian region in three successive seasons during the period 1963 to 1966 (Mikhalev 1997, Mikhalev 2000, when illegal Soviet fleets swept northwards from the Gulf of Aden, along the eastern shoreline of the Arabian peninsula and eastwards across the Oman Sea as far as the Pakistan-India border. The final Soviet tally from this Arabian region campaign was 3,339 whales, including 1,294 blue whales, 954 sperm whales, 849 Bryde's whales and 242 humpback whales (Mikhalev 2000). ...
... This, along with other escalating human impacts, are the considered as the causes of its low population of less than 250 mature animals. 256,260 The population is at risk with scientists estimating that the population can handle no more than one mortality every two years as a result of growing human impacts. 261 Humpbacks in the southwest Indian Ocean are referred to by the IWC as stock "C", comprised of four sub-stocks: C1 off the coast of the East African Mainland Coast from South Africa to Kenya, C2 in the Mozambique channel between Comoros Islands and Aldabra (Seychelles), C3 around Madagascar and C4 off the Mascarene Islands. ...
A new collaborative report from WWF and science partners provides the first comprehensive look at whale migrations and the threats they face across all oceans, highlighting how the cumulative impacts from industrial fishing, ship strikes, pollution, habitat loss, and climate change are creating a hazardous journey.
Protecting Blue Corridors report visualises the satellite tracks of over 1000 migratory whales worldwide. The report outlines how whales are encountering multiple and growing threats in their critical ocean habitats – areas where they feed, mate, give birth, and nurse their young – and along their migration superhighways, or ‘blue corridors’.
The report is a collaborative analysis of 30 years of scientific data contributed by more than 50 research groups, with leading marine scientists from Oregon State University, the University of California Santa Cruz, the University of Southampton and others.
Case studies highlight hotspots and risks that whales navigate on their migrations, some of which can be thousands of kilometers each year. As a result of these hazards, six out of the 13 great whale species are now classified as endangered or vulnerable by the International Union for Conservation of Nature, even after decades of protection after commercial whaling. Among those populations most at risk is the critically endangered North Atlantic right whale, a species that migrates between Canada and the United States. It is at its lowest point in 20 years – numbering only 336 individuals.
Protecting Blue Corridors calls for a new conservation approach to address these mounting threats and safeguard whales, through enhanced cooperation from local to regional to international levels. Of particular urgency is engagement with the United Nations, which is set to finalise negotiations on a new treaty for the high seas (Areas Beyond National Jurisdiction) in March 2022.
The benefits from protected blue corridors extend far beyond whales. Growing evidence shows the critical role whales play maintaining ocean health and our global climate – with one whale capturing the same amount of carbon as thousands of trees. The International Monetary Fund estimates the value of a single great whale at more than US1 trillion for the current global population of great whales.
... Humpback whales (Megaptera novaeangliae) are a migratory species. Except for humpback whales in the Arabian Sea (Mikhalev, 1997), individual females and males, in all maturational classes, and different reproductive states, in all other populations, migrate from high-latitude summer/autumn feeding areas to low latitude winter/spring breeding grounds (Chittleborough, 1965;Dawbin, 1966;. Feeding is rare or absent in winter breeding grounds, when most behaviours are related to calving and mating. ...
Agonistic competitive social behaviour in humpback whales [Megaptera novaeangliae (Borowski, 1781)] has been extensively studied and reported in previous research. However, non-agonistic social behaviour in humpback whale pods has not been systematically studied. We investigated the social behaviour of 3,949 humpback whale pods over a period of 14 years during August, September, and October in Hervey Bay (Queensland, eastern Australia), a preferential female stopover early in the southern migration. Modelling and analyses of the data examined the factors influencing the occurrence and timing of non-agonistic social behaviour pods, agonistic competitive pods and newly associated pods. Non-agonistic social behaviour was observed more frequently during August when mature females, including early pregnant and resting females, co-occur and socially interact with immature males and females. Overall, relatively few mature males visit Hervey Bay. Agonistic competitive behaviour was observed with increasing frequency during September and October when mother-calf pods, with few escorts predominated. Mother-calf pods in Hervey Bay spent most of their time alone involved in maternal care. Agonistic competitive behaviour is related to the decreasing numbers of potentially oestrous females toward the end of the season. Non-agonistic social behaviour and agonistic competitive behaviour were more frequently observed in larger and newly associated pods. Overall, non-agonistic social behaviour pods were more prevalent than agonistic competitive social behaviour pods. The results of this study substantiate that non-agonistic social behaviour may be more prevalent than aggressive agonistic social behaviour in site-specific locations and habitats, depending upon the classes and timings of humpback whales using such habitats.
... The Swatch and surrounding deep waters are very important as fishing ground for tuna and other large pelagic fishes and for biodiversity, specifically deep water species of fish, cetaceans and other large marine vertebrates (e.g., Ahmed, 1985;Mikhalev, 1997Mikhalev, , 2000Kiani et al., 2013) . ...
Beaked whales (Ziphiidae) are rarely reported in the Arabian Sea. Four new cases (five individuals) were documented in deep waters offshore Pakistan through a pilot programme in 2015-2018 where trained fishers video-recorded net entanglements in the pelagic tuna drift gillnet fishery. Videos were analysed frame-by-frame. The large body size (est. 5-6m) of one specimen, its moderately bulbous melon, long tubular rostrum and a large falcate dolphin-like dorsal fin, indicated Longman's beaked whale Indopacetus pacificus. It represents the first record for Pakistan (EEZ), and with a stranding at Gujarat, India, a second for the northern Arabian Sea. The other 4 ziphiids were significantly smaller (est. 3-4.5m), with a decidedly non-bulbous melon, variable short to moderately short rostra, falcate to subtriangular dorsal fin and a nondescript greyish colouration, identified as Mesoplodon spp. Video quality was poor but none of the specimens showed tusks, arched mandible lines or noticeable linear tooth rakes, practically excluding adult males. The successful release of all the live net-entangled beaked whales is unprecedented. The simultaneous bycatch of two mesoplodonts in the same net set is equally exceptional. This citizen science strategy adds to our understanding of the distribution of I. pacificus and mesoplodonts, which may be more common in the Arabian Sea than the scarce literature suggests. If significant bycatch of beaked whales is confirmed, the massive tuna gillnet fishing effort in the Arabian Sea could have negative implications for their conservation status.
... The Swatch and surrounding deep waters are very important as fishing ground for tuna and other large pelagic fishes and for biodiversity, specifically deep water species of fish, cetaceans and other large marine vertebrates (e.g., Ahmed, 1985;Mikhalev, 1997Mikhalev, , 2000Kiani et al., 2013) . ...
Pakistan has total coastline of about 990 km, while diversity, distribution and abundance of cetaceans are not well understood. All historic and most recent information are based on opportunistic stranding or incidental bycatch in fishing nets, which has been a big obstacle in formulating any conservation strategy for cetaceans in Pakistan. Recent initiatives were taken and conducted surveys along the entire coastline. Although, some species have been identified well, however, still, lack of detail studies on population biology and ecology of these species. Many other species are still lack of the expertise for identification or they were misidentified. So far, a total of 18 cetacean species have been recorded in Pakistan, consisting of 3 endangered species namely blue whale ( Balaenoptera musculus ), Arabian sea humpback whale ( Megaptera novaeangliae ) and Indian Ocean humpback dolphin ( Sousa plumbea ), 2 vulnerable such as the sperm whale ( Physeter macrocephalus ) and Indo-Pacific finless porpoise ( Neophocaena phocoenoid ) and others 13 species are listed as data deficient. Future studies should be focused to systematic investigations on stock identification, distribution, and also evaluate the anthropogenic threats to the cetaceans. As the cetaceans has unique evolutionary history among mammals and top predator in the aquatic ecosystem. The national policies and legislations should be revised to declare them as protected species. More protected areas should be established in some important areas, such as Indus delta along the Sindh coastline to sustain the integrity of habitat and long-term conservation and management of cetaceans along the entire coastal area of Pakistan.
... One population that may shed light on the question of what drives the onset of singing is the non-migratory Arabian Sea humpback whales. Little is known about this genetically distinct population, but they have been found to sing on a Northern Hemisphere seasonal cycle and female reproduction is similarly seasonal based upon examination of foetal lengths in Soviet whaling data, similar to their migratory counterparts (Mikhalev 1997;Cerchio et al. 2016). Moreover, the population is derived from a founder event originating in the Southern Hemisphere (Pomilla et al. 2014), inferring that during the adaptation to residency in the Arabian Sea, they switched breeding cycle to a Northern Hemisphere timing. ...
At the onset of the winter breeding season, male humpback whales begin a prominent breeding behaviour, singing. Early songs are produced on summer feeding grounds prior to migration, but little is known about the proximate cues for the initiation of this behaviour, nor where or when it begins. We document the phenology of humpback whale singing along the western North Atlantic coast ranging from Newfoundland and Labrador, Canada to Massachusetts, USA through the fall-winter of 2015–16 (seven stations) and 2016–17 (three stations). Acoustic data from static recorders were categorised as containing humpback whale non-song calls, song fragments, or full songs. First heard in September, singing occurred throughout the fall-winter, but was not regular until October. Latitude, temperature, photoperiod, sea surface pressure, and wind speed were considered as potential explanatory variables for four definitions of song onset using forward stepwise regression. Final models included the environmental variables with photoperiod negatively correlated to singing (coefficient = −657; p-value = 0.04). Reliable environmental cues, such as photoperiod, may produce a heritable physiological response, resulting in whales acquiring the capacity and motivation to sing, with the subsequent timing and nature of song production influenced by other factors.
... Isolated populations exhibit different breeding patterns compared to other surrounding stocks that migrate to different latitudes during the year (Mikhalev, 1997;Notarbartolo-Di-Sciara et al., 2003;Pomilla et al., 2014). Individuals from these populations do not migrate out of their basins, so they feed and reproduce there throughout the year (Canese et al., 2006;Jiménez-López et al., 2019). ...
... Pakistan's Arabian Sea coast is known to have a well diversified whale fauna which includes both baleen and toothed whales documented by a number of studies including Gore et al. (2012), Kiani and Siddiqui (2009), Kiani (2014Kiani ( , 2015aKiani ( , 2015b, Mikhalev (1997;2000), Minton et al. (2015) and Moazzam and Nawaz (2017, 2018, 2019. Among baleen whales, three species including Arabian Sea humpback whales (Megaptera novaeangliae), blue whales (Balaenoptera musculus) and Bryde's whales (Balaenoptera brydei) have been reported from Pakistan, whereas toothed whales include sperm whales (Physeter macrocephalus), killer whales (Orcinu orca), dwarf sperm whales (Kogia sima), Longman's beaked (or tropical bottlenose (Indopacetus pacificus) and Cuvier's beaked whales (Ziphius cavirostris). ...
In 2012 WWF-Pakistan initiated an observer programme to monitor tuna gillnet operations in the coastal and offshore waters of Pakistan. Among other things, these observers were assigned to report observations of whales encountered during fishing operations. These vessels (with onboard observers) provided a platform of opportunity for recording the spatial and temporal distribution of whales in the Northern Arabian Sea. During 2019 a total of 7 sightings of Arabian Sea humpback whales, 1 sighting each of blue whales and Bryde’s whales, 6 sightings of sperm whales,8 sightings of baleen whales (that could not be identified to species level due to lack of adequate photographic or video evidence) and 3 records of entanglement and mortality of Cuvier’s beaked whales.. Fewer whales were recorded through the programme in 2019 than 2018 and 2017 when a total of 35 and 95 sightings of whale were recorded respectively. This decrease in sightings is attributed to many factors, including early closure of the fishing season in early April 2019 because of low catches and unreliable prices of tuna in the market. As such the fishery was closed for four months from mid-April to mid-August instead of the usual two months of June and July. Extremely high sea surface temperatures during September to October 2019 (possibly an oceanic heat wave) were believed to be the cause of reduced tuna catches. Therefore, only a few tuna boats remained operational during this period. An unprecedented jellyfish bloom of Crambionella orsini from September 2019 onward forced fishermen to stop fishing operations during this period. Furthermore, the observer programme was completed on September, 2019, after which only 45 out of 75 observers voluntarily continued to provide information about sightings. The paper also reports on two baleen whale strandings - a Bryde’s whale (Balaenoptera brydei) stranded on the rocky shore at Gunz, western coast of Pakistan and a blue whale in Pushukan, Gwadar (West Bay).
... Pakistan's Arabian Sea coast is known to have a well diversified whale fauna which includes both baleen and toothed whales documented by a number of studies including Gore et al. (2012), Kiani and Siddiqui (2009), Kiani (2014Kiani ( , 2015aKiani ( , 2015b, Mikhalev (1997;2000), Minton et al. (2015) and Moazzam and Nawaz (2017, 2018, 2019. Among baleen whales, three species including Arabian Sea humpback whales (Megaptera novaeangliae), blue whales (Balaenoptera musculus) and Bryde's whales (Balaenoptera brydei) have been reported from Pakistan, whereas toothed whales include sperm whales (Physeter macrocephalus), killer whales (Orcinu orca), dwarf sperm whales (Kogia sima), Longman's beaked (or tropical bottlenose (Indopacetus pacificus) and Cuvier's beaked whales (Ziphius cavirostris). ...
In 2012 WWF-Pakistan initiated an observer programme to monitor tuna gillnet operations in the coastal and offshore waters of Pakistan. Among other things, these observers were assigned to report observations of whales encountered during fishing operations. These vessels (with onboard observers) provided a platform of opportunity for recording the spatial and temporal distribution of whales in the Northern Arabian Sea. During 2019 a total of 7 sightings of Arabian Sea humpback whales, 1 sighting each of blue whales and Bryde’s whales, 6 sightings of sperm whales,8 sightings of baleen whales (that could not be identified to species level due to lack of adequate photographic or video evidence) and 3 records of entanglement and mortality of Cuvier’s beaked whales.. Fewer whales were recorded through the programme in 2019 than 2018 and 2017 when a total of 35 and 95 sightings of whale were recorded respectively. This decrease in sightings is attributed to many factors, including early closure of the fishing season in early April 2019 because of low catches and unreliable prices of tuna in the market. As such the fishery was closed for four months from mid-April to mid-August instead of the usual two months of June and July. Extremely high sea surface temperatures during September to October 2019 (possibly an oceanic heat wave) were believed to be the cause of reduced tuna catches. Therefore, only a few tuna boats remained operational during this period. An unprecedented jellyfish bloom of Crambionella orsini from September 2019 onward forced fishermen to stop fishing operations during this period. Furthermore, the observer programme was completed on September, 2019, after which only 45 out of 75 observers voluntarily continued to provide information about sightings. The paper also reports on two baleen whale strandings - a Bryde’s whale (Balaenoptera brydei) stranded on the rocky shore at Gunz, western coast of Pakistan and a blue whale in Pushukan, Gwadar (West Bay).
... Movements are thought to be driven by foraging or social behaviors (e.g., Clapham et al., 1993;Tyack & Whitehead, 1982;Visser, Hartman, Pierce, Valavanis, & Huisman, 2011); however, Corkeron and Connor (1999) also suggested that migration could be influenced by predator avoidance, and highlight that not all whale populations migrate annually (Geijer, Notarbartolo di Sciara, & Panigada, 2016). Non-migratory populations that remain in tropical and subtropical waters year-round (Mikhalev, 1997;Širović, Bassett, Johnson, Wiggins, & Hildebrand, 2014) may be supported by yearround productive foraging grounds (Geijer et al., 2016), as well as reduced energetic expenditure afforded by foregoing long migratory movements (Brown, Corkeron, Hale, Schultz, & Bryden, 1995;Kennedy et al., 2014). Even within migratory populations, some individuals remain on feeding grounds over winter (e.g., Brown et al., 1995;Thomisch et al., 2016;Van Opzeeland, Van Parijs, Kindermann, Burkhardt, & Boebel, 2013). ...
Six baleen whale species are found in the temperate western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. There is mounting evidence of distributional shifts in many species, including marine mammals, likely because of climate‐driven changes in ocean temperature and circulation. Previous acoustic studies examined the occurrence of minke (Balaenoptera acutorostrata) and North Atlantic right whales (NARW; Eubalaena glacialis). This study assesses the acoustic presence of humpback (Megaptera novaeangliae), sei (B. borealis), fin (B. physalus), and blue whales (B. musculus) over a decade, based on daily detections of their vocalizations. Data collected from 2004 to 2014 on 281 bottom‐mounted recorders, totaling 35,033 days, were processed using automated detection software and screened for each species’ presence. A published study on NARW acoustics revealed significant changes in occurrence patterns between the periods of 2004‐2010 and 2011‐2014; therefore, these same time periods were examined here. All four species were present from the Southeast United States to Greenland; humpback whales were also present in the Caribbean. All species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. Each of the species showed significant changes in acoustic occurrence after 2010. Similar to NARWs, sei whales had higher acoustic occurrence in mid‐Atlantic regions after 2010. Fin, blue, and sei whales were more frequently detected in the northern latitudes of the study area after 2010. Despite this general northward shift, all four species were detected less on the Scotian Shelf area after 2010, matching documented shifts in prey availability in this region. A decade of acoustic observations have shown important distributional changes over the range of baleen whales, mirroring known climatic shifts and identifying new habitats that will require further protection from anthropogenic threats like fixed fishing gear, shipping, and noise pollution.
... The humpback whale is one of the best known whale species. It is cosmopolitan and migrates between low-latitude coastal breeding grounds and high latitude feeding grounds (Clapham, 2009), with the exception of one resident subpopulation in the Arabian Sea, where whales remain in tropical waters year-round (Mikhalev, 1997). Humpbacks feed in summer, on euphausiids and small schooling fish, engulfing their prey with their large mouth, and spend the winter in tropical and subtropical waters, in calving bays close to shore, islands or reefs (Clapham, 2009). ...
Relevant baselines on the historical distribution and abundance of species are needed to support appropriate conservation targets for depleted species, but the full scale of cumulative human impacts on ecosystems is highly underestimated. In this project, I investigated the challenges and opportunities of combining historical data with analytical methods to improve these historical baselines. Occurrence data from archaeological, historical and industrial sources were reviewed for seven cetacean and three pinniped species, revealing range contractions and population depletions from prehistorical times to today. For five whale species, I used species distribution modelling to combine 19th Century whaling records with environmental data, to estimate pre-whaling distributions. For the highly depleted North Atlantic right whale, (Eubalaena glacialis), I obtained a detailed estimate of pre-whaling distribution and abundance by inferring from the historical distribution and abundance of its congeneric North Pacific right whale (E. japonica). These results suggest that the North Atlantic right whale occupies a small fraction of its historical range and that its current population represents <5% of its historical abundance, with implications for the management, monitoring and conservation targets of this species. More generally, these results emphasize the utility of considering historical data to understand the extent to which species have been impacted by humans, assess their current level of depletion, and inform the options available for their future recovery.
... Though, the progesterone threshold that we used to infer pregnancy was not validated and could be slightly inaccurate. Indeed, when compared to previous reports, our pregnancy rates and blubber progesterone levels do appear low (Nishiwaki, 1959;Chittleborough, 1965;Mikhalev, 1997Mikhalev, , 2000Clark et al., 2016;Pallin et al., 2018). Discrepancies in blubber progesterone levels could occur if females in this study were sampled at a different gestational stage than in previous studies. ...
For most cetacean species, there is little known about how an individual's physiology influences its behaviour. Humpback whales (Megaptera novaeangliae) are a good candidate to examine such links as they have a well-described distribution and behaviour, can be consistently sampled using remote biopsy systems, and have been the subject of several previous endocrine studies. The objective here was to examine whether a female humpback whale's social state (i.e. escorted by a male or not) is related to her endocrine condition, and whether male dominance ranking is related to testosterone levels. Skin and blubber biopsies were collected from the east and west Australian humpback whale populations in 2010-2016 (n = 252) at multiple times throughout the winter-spring breeding season. Steroid hormones were extracted from blubber and concentrations of progesterone (a marker for pregnancy), testosterone (a marker of male testicular activity) and oestradiol (a potential marker of ovarian activity) measured using enzyme-immunoassays. Principal escorts-the dominant males in mixed sex groups-had significantly higher blubber testosterone levels (mean ± SE; 1.43 ± 0.20 ng/g wet weight) than subordinate, secondary escorts (0.69 ± 0.06 ng/g wet weight). Females that were escorted by males typically possessed elevated blubber oestradiol levels (1.96 ± 0.25 ng/g wet weight; p = 0.014); few were considered to be pregnant (p = 0.083). 'Unescorted' females displayed characteristically lower blubber oestradiol levels (0.56 ± 0.06 ng/g wet weight). Together, these results are consistent with 'challenge hypothesis' theory and suggest the existence of associated reproductive patterns in humpback whales.
... Similarly, year-round calving and ovulation frequency on the inshore Bryde's whales (Balaenoptera edeni) off South Africa proved that this resident population is an aseasonal breeder (Best, 2001). In contrast, the resident humpback whale (Megaptera novaeangliae) population in the Arabian Sea showed seasonal reproductive habits lasting from January to May (Mikhalev, 1997). ...
Fin whales in the Gulf of California constitute a resident population genetically isolated from the rest of the North Pacific Ocean. Its small population size and the scarce information available about its dynamics in a semi-enclosed sea underline the importance of conducting studies about its reproduction. Given the monsoonal regime that dominates the oceanographic habitat of this region, we hypothesized seasonality in the population’s reproductive activity. To test this, we validated and assayed testosterone and progesterone from blubber biopsies of free-ranging individuals. Lactating females exhibited low progesterone concentrations, whereas a group of females of unknown reproductive stage, but with extremely high progesterone concentrations, showed strong evidence of separation and were considered to be likely ovulating or pregnant. A seasonal model of testosterone concentrations showed a high peak during the late summer. This trend was supported by the first documentation of courtship events and by the recording of a female with high progesterone concentration during summer and re-sighted with a calf 1 year later. Therefore, the breeding in this resident population would be seasonal, as it is in migratory baleen whales, but occurring during the summer/autumn, which is the least productive season in the Gulf of California. Our study represents an important input to assist in future management policies of this protected population.
... Reproduction in all but the Arabian Sea population of humpback whales (Mikhalev, 1997) is based around an annual migration from high latitude nutritionally productive feeding grounds to low latitude warm breeding grounds on which all but calves-of-the-year fast (Baker et al., 1985;Chittleborough, 1965;Katona and Beard, 1990), although occasional feeding on some breeding grounds has been observed (Gendron, 1993). Humpback whales of both sexes and all age classes migrate between feeding and breeding grounds with migratory timing a function of sex, age class, and reproductive and nutritional condition (Chittleborough, 1965;Craig et al., 2003;Straley et al., 1994). ...
Understanding reproductive profiles and timing of reproductive events is essential in the management and conservation of humpback whales (Megaptera novaeangliae). Yet compared to other parameters and life history traits, such as abundance, migratory trends, reproductive rates, behavior and communication, relatively little is known about variations in reproductive physiology, especially in males. Here, an enzyme immunoassay (EIA) for testosterone was validated for use in biopsy samples from male humpback whales. Analyses were conducted on 277 North Pacific male humpback whale blubber samples, including 268 non-calves and 9 calves that were collected in the Hawaiian breeding grounds and the Southeast Alaskan feeding grounds from 2004 to 2006. Testosterone concentrations (ng/g) were significantly different between non-calves sampled in Hawaii (n = 182) and Alaska (n = 86, p < 0.05) with peak testosterone concentrations occurring in the winter (January–March) and the lowest concentrations occurring in the summer (June–September). Fall and spring showed increasing and decreasing trends in testosterone concentrations, respectively. Blubber testosterone concentrations in non-calves and calves sampled in Alaska were not significantly different. Blubber and skin from the same individual biopsies (n = 37) were also compared, with blubber having significantly higher testosterone concentrations (p < 0.05) than skin samples. We found variability in testosterone concentration with age, suggesting that male humpbacks reach peak lifetime testosterone concentrations in the breeding grounds around age 8–25 years. The testosterone profile of male humpback whales follows a predictable pattern for capital breeders, where testosterone begins to increase prior to the breeding season, stimulating the onset of spermatogenesis. Incorporation of reproductive hormonal profiles into our overall understanding of humpback whale physiology will shed additional light on the timing of reproduction and overall health of the recently delisted Hawaii distinct population segment (DPS).
Este estudo dedica-se à análise do status normativo da conservação das baleias-jubarte, com foco especial no contexto brasileiro. Explora-se os efeitos dessas normativas na proteção efetiva dessa espécie, considerando também as influências do direito internacional. Para atingir esse objetivo, examinam-se as ferramentas jurídicas utilizadas para a conservação das baleias-jubarte, assim como os avanços regulatórios que integram as políticas nacionais de conservação. A pesquisa também aborda aspectos relacionados à ecologia desses animais, os principais impactos ambientais que os afetam, as iniciativas de conservação em andamento e os desafios enfrentados tanto pela comunidade internacional quanto pelo Brasil. A compreensão abrangente dessas questões é importante para desenvolver estratégias eficazes de conservação e garantir a sobrevivência dessa espécie. Além da revisão da legislação, doutrina e jurisprudência pertinentes, são considerados os dados acerca da abundância populacional das baleias-jubarte, obtidos por meio do monitoramento conduzido por pesquisadores e institutos especializados. Concluiu-se que o Brasil tem normas rigorosas para proteger a fauna em seu território, incluindo os cetáceos, mas desafios persistentes demandam uma abordagem integrada de fiscalização e cooperação institucional.
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.
Sousa-Lima, R., Cheeseman, T., Jackson, J., Friedlaender, A., Pallin, L., Olio, M., Liberali-Wedekin, L., Daura-Jorge, F., Cardoso, J., Santos, J., Fortes, R., Araújo, M., Bassoi, M., Beaver, V., Bombosch, A., Clark, C., Denkinger, J., Boyle, A., Rasmussen, K., Savenko, O., Avila, I.C., Palacios, D., Kennedy, A.,, & M. Marcondes. 2022. The Southern Ocean Exchange: Humpback whales are crossing putative boundaries in Antarctic feeding areas. In Memories 24th Biennial Conference on the Biology of Marine Mammals, Pp: 600-601. August 1-5, Florida, USA.
The blue whale (Balaenoptera musculus) is one of the most common cetaceans in the waters around Sri Lanka and in a worldwide context one of the highest low-latitude sighting rates for this species has been recorded in these waters. As genetic analyses, acoustic studies and even long-term sighting surveys for blue whales in these waters are limited, the taxonomic status and population affinities of these animals are not definitively known at present. Sighting records of this species were examined from the waters around Sri Lanka and stranding records from the coasts of both Sri Lanka and India in terms of seasonality of occurrence and it was found that the species is clearly present in these waters throughout the year. This, together with secondary data on certain morphological characteristics and behavioural anomalies, indicates that these waters are ecologically important to blue whales in the Northern Indian Ocean and questions are raised regarding the subspecific identity and population affinities of the animals in the region. It is not clear if they belong to either of the two subspecies currently recognised for the Southern Ocean and Indian Ocean region: their apparently non-migratory nature is akin to the pygmy blue whale B.m. brevicauda, while some morphological and behavioural characteristics are indicative of Antarctic blue whales of the subspecies B.m. intermedia. This raises the possibility of an entirely different or intermediate subspecies and the need to re-examine B.m. indica as a third subspecies in the Northern Indian Ocean. As clarifying their taxonomic status is important in the context of conservation and management, multi-disciplinary studies are urgently needed.
Humpback whalesHumpback whale(Megaptera novaeangliae)Megaptera novaeangliae occur in all major oceans. Given this worldwide distribution, and since they tend to migrate along coastlines, they are one of the best known of the baleen whalesBaleen whale. Humpbacks are relatively easy to find and easy to observe. This, along with their surface behaviorsBehavior and attraction to vessels, makes them popular with whale-watching businesses. In the scientific world, their songSong and behaviorsBehavior have been studied since the 1970s, producing hundreds of scientific papers. Despite this, there are still many unsolved mysteries. Why do humpbacks sing (Chaps. 8 and 11), how do they locate their prey (Chap. 5), and how do they navigate when migrating (Chap. 4)? In this chapter, we focus on the mysteries of their social communicationCommunication. Communication and social complexitiesSocial complexity often go hand in hand. Animals with more complex social structuresSocial structure tend to have more complex vocal repertoiresVocal repertoire, perhaps peaking, with humans. Within the baleen whalesBaleen whale, humpback whalesHumpback whale are considered an exception. Present knowledge indicates that humpbacks have a relatively complex acoustic repertoireAcoustic repertoire but work on their breedingBreedingsocial systemSocial system has considered them to be socially simple. Animals regarded as having a simple social structureSocial structure tend to have small group sizes and a lack of repeat associations between individuals over time. Humpback whalesHumpback whale meet this criteria in that they form temporary associations between a small number of individuals, and these associations are not repeated over time, leading to the conclusion that their social structureSocial structureis simple and individually basedIndividually-based. Why then do humpbacks have what could be considered a complex acoustic repertoireAcoustic repertoire? Is the conclusion that they possess a simple social structureSocial structure supported by best available scientific evidence? This chapter illustrates that humpbacks may in fact have a complex social structureSocial structure, with complexity defined differently than traditional definitions of complexity (number in a group, number of repeat associations). Rather than forming large permanent groups with repeated interactions between individuals, humpback whalesHumpback whale during the breedingBreeding season form networks that encompass multiple groups. These groups are frequently changing membership, and animals are constantly moving into, and out of this network. Whales must therefore continuously assess, and respond to, a changing social environment. Given that humpbacks likely rely on acoustic communicationCommunication to manage these interactions, this added layer of social complexitySocial complexity may go toward explaining their large and varied vocal repertoireVocal repertoire. Perhaps communicative and social complexitiesSocial complexity do go hand in hand for the humpback whaleHumpback whale.
Baleen whalesBaleen whales are specialized to find and exploit preyPrey that form dense patches seasonally within broad ocean areas. Most populations have an annual reproductive cycleAnnual reproductive cycle that separates their breeding seasonBreeding season from their feeding seasonFeeding season, often with long-distance migrationsMigrationsbetween feedingFeedingand breedingBreeding areas. The longest bond we know of for most baleen whale species is the mother-calf bondMother-calf bond. CalvesCalve suckle for five to seven months in most species and wean by the next feeding seasonFeeding season. The species whose social behavior has been most studied is the humpback whaleHumpback whale, enabled by their distribution, which often is near shore, and their individually distinctive natural markings. Some humpback whalesHumpback whalefeedingFeeding on mobile prey form stable groupsStable group where each individual learnsLearn specific roles to perform coordinated group foragingGroup foraging. Aside from these groups, which may last for many years, most baleen whale groups are reported to be fluid with few strong associations between individuals other than mother and calfCalf. However, most researchers define whale groups in terms of the number of whales that are close enough to be sighted within a certain distance of one another. Sound propagates so well underwater that whale sounds can be heardHeard at distances of tens to hundreds of kilometers away. This means that whales may be able to maintain contact over much greater ranges than are usually assessed by human observers—they may form long-range “heards”Heard in addition to shorter range “herdsHerd.” The social organization of whales during the breeding seasonBreeding season is structured in part by songsSong—acoustic reproductive advertisement displays. The potential scale of “heards”Heard is indicated by the ability of scientists to track one singingSingingblue whaleBlue whale for 43 days as it swam > 1700 km. Scientists will start to develop a fuller understanding of the social organization of baleen whales when they apply methods that can make observations and test hypotheses over the temporal and spatial scales at which baleen whales move and communicate.
Humpback whales (Megaptera novaeangliae) are a cosmopolitan species and perform long annual migrations between low-latitude breeding areas and high-latitude feeding areas. Their breeding populations appear to be spatially and genetically segregated due to long-term, maternally inherited fidelity to natal breeding areas. In the Southern Hemisphere, some humpback whale breeding populations mix in Southern Ocean waters in summer, but very little movement between Pacific and Atlantic waters has been identified to date, suggesting these waters constituted an oceanic boundary between genetically distinct populations. Here, we present new evidence of summer co-occurrence in the West Antarctic Peninsula feeding area of two recovering humpback whale breeding populations from the Atlantic (Brazil) and Pacific (Central and South America). As humpback whale populations recover, observations like this point to the need to revise our perceptions of boundaries between stocks, particularly on high latitude feeding grounds. We suggest that this "Southern Ocean Exchange" may become more frequent as populations recover from commercial whaling and climate change modifies environmental dynamics and humpback whale prey availability. Humpback whale migration patterns and breeding stocks. Humpback whales (Megaptera novae-angliae) are a cosmopolitan species 1 which can migrate up to 8500 km between seasonal breeding and feeding OPEN
Acoustic methods can provide important data on the occurrence and distribution of migratory species. Information about Antarctic Minke whale (Balaenoptera bonaerensis) occurrence in the winter breeding grounds is scarce, mostly limited to old records from whaling stations before 1960’s international moratory, such as Costinha Station in Northeastern Brazil (6° S / 34° W). This work describes the occurrence of the Antarctic minke whale (AMW) through Bio-duck acoustic detections in the Santos Basin, South-Southeastern Brazil (22º and 28º S / 42º and 48º W), registered between November 12 and December 19, 2015. AMW calls were detected for 12 days. We detected and classified 9 different Bio-duck calls in Brazilian coast waters, evidencing a high diverse acoustic behaviour for the minke whale breeding ground. This is the first study to describe the acoustic diversity of AMW vocalizations in lower latitudes, constituting important information to the conservation and management of cetaceans and their habitat. Therefore, our study presents the foremost acoustic evidence of the Antarctic minke whale in Brazil, utilizing high technological passive acoustic methods, such as autonomous underwater vehicle (SeaGlider) sampling.
Killer whales are the only predator of bowhead whales and are increasingly present in the Arctic. The ecology and population sizes of Arctic killer whales are poorly understood, but targeted research documenting the behavior and demography of these animals and their predatory impact on Arctic endemic marine mammals, including bowhead whales, has intensified in the past 10 years. This work suggests killer whales substantially impact bowhead whales and other Arctic marine mammals, and changing sea ice conditions and/or recovery of killer whale populations after industrial whaling, are reshaping the patterns and intensity of killer whale predation in the Arctic.
From prehistoric times, natives hunted whales for food in the shallow coastal waters of Europe, the Chukchi Peninsula, Kamchatka, the Japanese islands and Alaska. The catch levels were minimal and did not affect the health of whale populations.
The Gulf of California, Mexico is home to many cetacean species, including a presumed resident population of fin whales, Balaenoptera physalus. Past studies reported very low levels of genetic diversity among Gulf of California fin whales and a significant level of genetic differentiation from con-specifics in the eastern North Pacific. The aim of the present study was to assess the degree and timing of the isolation of Gulf of California fin whales in a population genetic analysis of 18 nuclear microsatellite genotypes from 402 samples and 565 mitochondrial control region DNA sequences (including mitochondrial sequences retrieved from NCBI). The analyses revealed that the Gulf of California fin whale population was founded ~2.3 thousand years ago and has since remained at a low effective population size (~360) and isolated from the eastern North Pacific (Nem between 0.89–1.4). The low effective population size and high degree of isolation implied that Gulf of California fin whales are vulnerable to the negative effects of genetic drift, human-caused mortality and habitat change.
Megaptera novaeangliae in the North Pacific, appear to form geographically isolated feeding herds which intermingle on one or more wintering grounds. Mark-recapture analyses suggest a seasonal population of 327-421 in the SE Alaska feeding region, and 1113-1701 on the Hawaiian wintering grounds. In Hawaii, multiple sightings of 18 sexually mature females provided an estimated calving rate (calves/female/year) of 0.58, but this value may be inflated. In SE Alaska, multiple sightings of 41 mature females provided an estimated calving rate of 0.37, probably a better estimate of current reproductive rates. On the Hawaiian wintering ground, social organization can be described as a polygynous mating system involving male-male competition for mature females. In SE Alaska, the foraging strategies of humpback whales appear to be noncompetitive and, on occasion, cooperative. -from Authors
Samples from 136 humpback whales Megaptera novaeangliae, representing 5 feeding aggregations in the North Atlantic and 1 in the Antarctic, were analyzed with respect to the sequence variation in the mitochondrial (mt) control region. A total of 288 base pairs was sequenced by direct sequencing of asymmetrically amplified DNA. Thirty-one different haplotypes were identified. The nucleotide diversity for the total sample was estimated to be 2.6 %, which is high relative to other North Atlantic cetaceans. The degree of genetic differentiation in various subsets of the samples was estimated and tested for statistical significance by Monte Carlo simulations. Significant degrees of heterogeneity were found between the Antarctic and all North Atlantic areas, as well as between Iceland and the western North Atlantic samples. A genealogical tree was estimated for the 31 haplotypes and rooted with the homologous sequence from a fin whale Balaenoptera physalus. The branching pattern in the genealogical tree suggests that the North Atlantic Ocean has been populated by 2 independent influxes of humpback whales. The combined results from the homogeneity tests and the genealogical tree indicate that behaviour (in this case maternally directed site fidelity to a foraging area) can influence the population structure of marine cetaceans on an evolutionary time scale.
Over 9000 photographs of humpback whale flukes have been collected. As of 31 December 1986, 3647 individual whales were represented. Over 1100 photographically-verified resightings of individually-known humpbacks demonstrated the existence of at least 4, probably 5, separate feeding aggregations: Iceland-Denmark Strait; W Greenland; Newfoundland (including the Labrador coast); Gulf of St. Lawrence; and Gulf of Maine-Scotian Shelf. Individual whales returned annually to a particular feeding region, but whales from all feeding aggregations migrated to nearshore areas and banks in the Dominican Republic, Puerto Rico and the Virgin Islands for breeding. The variance-weighted mean of annual capture-recapture estimates of the total North Atlantic humpback population for years 1979-1986 was 5502 ± 2617 (95% CI). -from Authors
The crude birth rate during 1979-87 ranged from 0.045-0.103 (mean 0.079), with no significant year-to-year variation. An alternative measure gave a mean reproductive rate of 0.41 calves per mature female per year. Data suggest that the majority of females attain sexual maturity by the age of 6. Of 94 calves born prior to 1987, 72 (76.6%) were resighted in at least one year after separation from their mothers, providing further support for the belief that the composition of a humpback whale feeding stock is determined matrilineally. Entanglements in commercial fishing gear may represent a significant source of mortality in this population. -from Authors
Standard metabolism is estimated for the fin whale, Balaenoptera physalus, from the energy yield of lipid stores consumed while in regions of limited prey availability. The metabolic rate appears better described by a surface rather than a volumetric rule. The larger body size of some Antarctic Balaenoptera compared with those of the Northern Hemisphere is attributed to selection for body proportions that reduce the specific metabolic rate and establish an optimal surface area for deposition of a lipid cache. Such proportions allow short-term forays into areas where prey is extremely dense but of restricted seasonal availability, and permit extended use of lipid stores during exclusion to warmer but less productive waters. Thus, adult body size within species is inversely correlated with the length of the feeding season and directly correlated with prey availability during that period. As differences in diversity of prey and/or their year-round availability become less marked between hemispheres, so do the body-size differences of the lesser rorquals. This is also applied to odontocetes. Thermal homeostasis is considered to be equally dependent upon morphology and behavior. Minimal densities of prey necessary for the maintenance of rorquals could be estimated from certain known parameters.
Aerial observations of humpback whales in the region of Point Cloates, Western Australia, during 1952 are recorded. The first southward-moving humpback whale was sighted on July 21, while decreasing numbers were seen moving northwards until early October. In 1952 the change from a predominantly northward migration of humpback whales to a southward migration
occurred close to August 24. The speed of migration of a number of these whales is recorded, the mean value being 4.3 kt. A few humpback whale calves were sighted early in July and a peak in their occurrence in August suggests maximum frequency of parturition early in August. A very great increase in the occurrence of calves in the area late in the season suggests that female humpback whales rearing calves move southwards later than other individuals. Some evidence is presented that Exmouth Gulf is a nursery area. The presence of some killer, fin, blue, and minke whales in the area is noted.
Evidence is presented that bites inflicted by the small squaloid shark, Zsistius brasiliegasis (Quoy and Gaimard), are the causes of crater wounds, crescentic wounds, and related scars on large pelagic fishes and cetaceans. This evidence consists of a crescentic "wound" experimentally produced on the side of a dead fish by a living Isistiis; specialized morphology of the shark's basihyoid cartilage and coracohyoideus muscles, lips, labial cartilages, and spiracles, that, together, enable the shark to form an oral vacuum on a srhooth surface; an experiment in which a living is is ti^^ formed such a vacuum; specialized morphology and arrangement of the mandibular teeth ; close agreement between the range of reported wound widths and the estimated range of bite widths of Isiqtius; agreement between the geographical ranges of Isistius and those fishes and cetaceans which bear crater wounds; and, finally, the presence in Isistius stomachs of hemispheroidal plugs of fish flesh. Speculation on the circumstances that may enable a small, slow shark to make contact with large, swift fishes and cetaceans is included. Isistius apparently qualifies as a temporary parasite. Probably the earliest account of the existence of small, round or oval, scooped-out wounds on the sides of large pelagic fishes is contained in an ancient legend of Samoa (A. Utu, personal communication), which states that atu (skip- jack tuna, Euthynnus pelamis (Linnaeus) ) en- tered Palauli Bay, and, upon approaching the beach, left small round pieces of their flesh as gifts to Tautunu, chief of that community. Evi- dence of this sacrifice was found by the people who caught the atu and observed fresh, round wounds on their sides. This legend provides one of many explanations that have been advanced regarding the causes of such wounds on large pelagic fishes as well as on whales and porpoises. This paper presents evidence that many crater wounds, crescentic wounds, and the resulting scars on pelagic fishes (Figure 1) , and open pit wounds and resulting scars on cetaceans are the results of bites in- flicted by the small squaloid shark, Isistius bra- siliensis (Quoy and Gaimard) . (A second spe- cies, Isistius pliitodus, was described by Garrick and Springer (1964) from the Gulf of Mexico. Although nothing is known of the behavior of
Hunting during the last 200 years reduced many populations of mysticete whales to near extinction. To evaluate potential genetic bottlenecks in these exploited populations, we examined mitochondrial DNA control region sequences from 90 individual humpback whales (Megaptera novaeangliae) representing six subpopulations in three ocean basins. Comparisons of relative nucleotide and nucleotype diversity reveal an abundance of genetic variation in all but one of the oceanic subpopulations. Phylogenetic reconstruction of nucleotypes and analysis of maternal gene flow show that current genetic variation is not due to postexploitation migration between oceans but is a relic of past population variability. Calibration of the rate of control region evolution across three families of whales suggests that existing humpback whale lineages are of ancient origin. Preservation of preexploitation variation in humpback whales may be attributed to their long life-span and overlapping generations and to an effective, though perhaps not timely, international prohibition against hunting.
It has been speculated that humpback whales, Megaptera novaeangliae, from the northeastern North Atlantic breed in tropical waters off the coast of West Africa and therefore that they represent a separate breeding population from that which winters in the West Indies. We determined the genotype at six microsatellite loci as well as the sequence of the first 288 nucleotides in the mitochondrial control region of 133 skin biopsies collected from humpback whales in the central North Atlantic (Iceland and Jan Mayen) and the northeastern North Atlantic (Bear Island and the northern coast of Norway). We detected no significant deviations from Hardy-Weinberg proportions nor any differences in genotype frequencies between localities at the nuclear loci. However, the mitochondrial analyses revealed two distinct matrilineal aggregations: the central and the northeastern North Atlantic. Our findings were not compatible with the idea of a separate eastern North Atlantic breeding ground unless one has been established recently. The proposed alternative hypothesis of a common North Atlantic panmictic population (wintering primarily in the West Indies) in which individual whales display maternally directed site-fidelity to specific feeding grounds was supported by re-sightings of two northeastern North Atlantic humpback whales in the West Indies.
The breeding cycle of the female Clapham PJ, Mayo CA (1987) ~epro'duction and recruitment of individually identified humpback whales, Megaptera novaeangliae, observed in Massachusetts Bay, 1979-1985
- R G Chittleborough
Chittleborough RG (1958) The breeding cycle of the female
Clapham PJ, Mayo CA (1987) ~epro'duction and recruitment
of individually identified humpback whales, Megaptera
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A note on recent sightings and strandings of cetaceans in Oman: Ra's Sawad1 to Rakhyut
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UNEP Marine Mammal Tech Rep 3:211-217
Terra Nova') expedition, 1910
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Lillie DG (1915) Cetacea. British Antarctic ('Terra Nova')
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- R I Currie
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Biological study on the humpbdck whales in the Antarct~c whaling areas IV and V
- H Omura
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Changeability of mammals. Nauka Zhizn 1-363
- A V Yablokov
Yablokov AV (1966) Changeability of mammals. Nauka Zhizn
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The color type of the humpback whale body (Megaptera nodosa Bonneterre) of the southern part of the Indian Ocean
- M V Ivashin
Ivashin MV (1958) The color type of the humpback whale
body (Megaptera nodosa Bonneterre) of the southern part
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General regularities in prenatal growth in whales and some aspects of their reproductive biology
- Y A Mikhalev
Mikhalev YA (1980) General regularities in prenatal growth
in whales and some aspects of their reproductive biology.
Rep Int Whal Commn 30:249-254
- M Nishiwaki
Nishiwaki M (1959) Humpback whales in Ryukyuan waters
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The southern stocks of whalebone whales
- Na Mackintosh
Mackintosh NA (1942) The southern stocks of whalebone
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Whales in the adjacent waters of
- H Omura
Omura H (1950) Whales in the adjacent waters of Japan. Sci
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Sur une nouvelle espece d e Megaptera (Megaptera indica) provenant du golfe Persique
- P Gervais
Gervais P (1888) Sur une nouvelle espece d e Megaptera
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Growth of fin whale in the northern Pacific
- S K Ohsumi
- M Nishiwaki
- T Hlbiya
Ohsumi SK, Nishiwaki M, Hlbiya T (1958) Growth of fin
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The humpback whale, Megaptera nodosa
- L H Matthews
Matthews LH (1937) The humpback whale, Megaptera
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Humpback whale songs from the North lndian Ocean
- H Whitehead
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Remarks on the d ~ s t r i b u t ~ o n a n d migration of whales, bascd on observations from Netherlands ships
T h ~ s
article was submitted to the edltor
Slijper EJ (1962) Whales. Cornell University Press, New York
Slijper EJ, van Utrecht WL. Naaktgeboren C (1964) Remarks
on the d ~ s t r i b u t ~ o n
a n d migration of whales, bascd on
observations from Netherlands ships. Bijdr D ~ e r k d 34:
3-93
Observations of cetaceans in the Gulf of Aden and the northwestern part of the Arabian Sea
- V L Yukhov
Yukhov VL (1969) Observations of cetaceans in the Gulf of
Aden and the northwestern part of the Arabian Sea. In:
Arsenev VA, Zenkovich BA. Chapski1 KK (eds) Marine
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Whales observed in the Indian Ocean. Notes on their distribution
- S G Brown
Brown SG (1957) Whales observed in the Indian Ocean. Notes
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Histoire naturelle d e la baleine B bosse (Megaptera boops)
- P J Van Beneden
Van Beneden PJ (1887) Histoire naturelle d e la baleine B
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4O:l-42
Populat~on characteristics of indlvldually identified humpback whales in the central and eastern North Paciflc: a summary and critique
- A Perry
- C S Baker
- L M Herlnan
Perry A, Baker CS, Herlnan LM (1990) Populat~on characteristics of indlvldually identified humpback whales in the
central and eastern North Paciflc: a summary and critique.
Rep Int Whal Commn (Spec Iss 12):307-317
Soviet Antarctic pelagic whaling after \YMrlI: review of actual catch data
- V A Zemsky
- A A Berzin
- Y A Mikhalev
- D D Tormosov
Zemsky VA, Berzin AA, Mikhalev YA, Tormosov DD (19951
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Appendlx 3
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- E J Slijper
Slijper EJ (1962) Whales. Cornell University Press, New York
Slijper EJ, van Utrecht WL. Naaktgeboren C (1964) Remarks
on the d~s t r i b u t~o n
a n d migration of whales, bascd on
observations from Netherlands ships. Bijdr D~e r k d 34:
3-93
T h c distribution of certain \vhales a s shown by logbook records of Amerlcan whaleships
- C Townsend
Townsend C H (1935) T h c distribution of certain \vhales a s
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Structure and stability of humpback whale groups off
- H Whitehead
Whitehead H (1983) Structure and stability of humpback
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Bor~sov V1 (1972) Whales and dolph~ns
- A V Yablokov
- V M Belkovich
Yablokov AV, Belkovich VM, Bor~sov V1 (1972) Whales and
dolph~ns. Academy of Sciences, Moscow (in Russian)