Proceedings of the Royal Society B: Biological Sciences, 2020
Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with... more Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with multiple beaked whale (BW) mass stranding events. Multinational naval ASW exercises have used MFAS offshore of the Mariana Archipelago semi-annually since 2006. We report BW and MFAS acoustic activity near the islands of Saipan and Tinian from March 2010 to November 2014. Signals from Cuvier's ( Ziphius cavirostris) and Blainville's beaked whales ( Mesoplodon densirostris ), and a third unidentified BW species, were detected throughout the recording period. Both recorders documented MFAS on 21 August 2011 before two Cuvier's beaked whales stranded on 22–23 August 2011. We compared the history of known naval operations and BW strandings from the Mariana Archipelago to consider potential threats to BW populations. Eight BW stranding events between June 2006 and January 2019 each included one to three animals. Half of these strandings occurred during or within 6 days after nava...
The Gulf of California, Mexico is home to many cetacean species, including a presumed resident po... more 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 (Nembetween 0.89–1.4). The low effective population size and high degree of isolation implied that Gulf of California fin whales ar...
Three aerial surveys were conducted along a portion of the northeastern coast of Sakhalin Island,... more Three aerial surveys were conducted along a portion of the northeastern coast of Sakhalin Island, Russia between August and September 1998. They were conducted to examine the spatial distribution of western gray whales on their feeding grounds, and in relation to current and planned industrial activity. A total of 32 gray whale groups, consisting of 38 whales, was sighted during the surveys. Group sizes ranged from 1-3 individuals (mean = 1.2, SD = 0.54), with 87.5% (n = 28) composed of single whales. All groups detected were within 5km of the shore and 93.8% (n = 30) were sighted inside 4km. Sighting locations ranged from 0.6-4.8km offshore, with an overall mean distance from shore of 2.5km (SD = 1.11). These data suggest that western gray whales feed primarily in waters less than 20m deep and relatively close to shore. The nutrient-rich effluent from a large coastal lagoon is believed to significantly enrich the near-shore benthic environment of the northeastern Sakhalin Island co...
The Eastern North Pacific gray whale (Eschrichtius robustus) is one population of large cetacean ... more The Eastern North Pacific gray whale (Eschrichtius robustus) is one population of large cetacean that has recovered from depletion resulting from commercial harvest in the mid- to late-1800s. It is believed that this population may be approaching, or possibly exceeding its carrying capacity as suggested by recent increases in mortality of all age and sex classes. Research on the breeding biology and phenology of gray whales that spend the winter in the coastal waters and lagoons of Baja California, Mexico has been conducted for many years. These studies contribute valuable information on the reproductive biology of this species, and the importance of their coastal lagoon habitats to their reproductive success. This paper reviews and summarises historical exploitation, conservation measures, the findings of research conducted on gray whales in their winter breeding range, potential natural and anthropogenic threats to this population, and makes recommendations for future research and...
SUMMARY A Symposium and accompanying workshops were held in Puerto Varas, Chile from 27-29 th Mar... more SUMMARY A Symposium and accompanying workshops were held in Puerto Varas, Chile from 27-29 th March 2012, to discuss recent advances in methods for non-lethal research on whales in the Southern Ocean. The first day (27 th March) was an open Symposium with invited experts who showcased new non-lethal research methods for whales in the Southern Hemisphere. The Symposium was followed by two days of Workshops that covered specific research areas. The Workshops were each one day
Research vessel and aerial platforms were used between 1997 and 2000 to collect genetic and photo... more Research vessel and aerial platforms were used between 1997 and 2000 to collect genetic and photographic data from a small populationof right whales that summers in the southeastern Bering Sea. Totals of 11 and six unique individuals were identified using photographicand genetic methods, respectively. Single matches between years occurred using both methods, and all genetic samples turned out to befrom male whales. Long-term research is needed to estimate the size of this population and to determine what threats the whales may befacing.
The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with ... more The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance pointing at strong gene-tree species tree discordance. Divergence times in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here we used high-coverage whole genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric d...
Proceedings of the Royal Society B: Biological Sciences, 2019
Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but in... more Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to ind...
R. Stone's In Depth News story “Dambuilding threatens Mekong fisheries” (2 December, p. [1084... more R. Stone's In Depth News story “Dambuilding threatens Mekong fisheries” (2 December, p. [1084][1]) explains why the scores of dams planned for the Mekong River are likely to have major impacts on eight of the world's largest freshwater fishes, all of which are already at risk of extinction.
Blue whales in the Northern Indian Ocean are a morphologically and acoustically distinct populati... more Blue whales in the Northern Indian Ocean are a morphologically and acoustically distinct population restricted to these waters. Off Sri Lanka a portion of the population concentrates near shore where they are exposed to a range of anthropogenic threats. We review available data to determine anthropogenic threats/stressors faced by this population and assign subjective rankings for the population-level severity of each threat/stressor based on severity, scope, and immediacy. With the cessation of direct illegal catches on this population in the late 1960s, we ranked ship strike as the most important population-level threat. Incidental catch, which includes entanglement and bycatch, is also important as it can result in death. Other less important stressors that may negatively impact this population include threats resulting from oil and gas development and pollution. However, some stressors can have a long-term cumulative impact that is difficult to assess. The most important researc...
Proceedings of the Royal Society B: Biological Sciences, 2020
Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with... more Mid-frequency active sonar (MFAS), used for antisubmarine warfare (ASW), has been associated with multiple beaked whale (BW) mass stranding events. Multinational naval ASW exercises have used MFAS offshore of the Mariana Archipelago semi-annually since 2006. We report BW and MFAS acoustic activity near the islands of Saipan and Tinian from March 2010 to November 2014. Signals from Cuvier's ( Ziphius cavirostris) and Blainville's beaked whales ( Mesoplodon densirostris ), and a third unidentified BW species, were detected throughout the recording period. Both recorders documented MFAS on 21 August 2011 before two Cuvier's beaked whales stranded on 22–23 August 2011. We compared the history of known naval operations and BW strandings from the Mariana Archipelago to consider potential threats to BW populations. Eight BW stranding events between June 2006 and January 2019 each included one to three animals. Half of these strandings occurred during or within 6 days after nava...
The Gulf of California, Mexico is home to many cetacean species, including a presumed resident po... more 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 (Nembetween 0.89–1.4). The low effective population size and high degree of isolation implied that Gulf of California fin whales ar...
Three aerial surveys were conducted along a portion of the northeastern coast of Sakhalin Island,... more Three aerial surveys were conducted along a portion of the northeastern coast of Sakhalin Island, Russia between August and September 1998. They were conducted to examine the spatial distribution of western gray whales on their feeding grounds, and in relation to current and planned industrial activity. A total of 32 gray whale groups, consisting of 38 whales, was sighted during the surveys. Group sizes ranged from 1-3 individuals (mean = 1.2, SD = 0.54), with 87.5% (n = 28) composed of single whales. All groups detected were within 5km of the shore and 93.8% (n = 30) were sighted inside 4km. Sighting locations ranged from 0.6-4.8km offshore, with an overall mean distance from shore of 2.5km (SD = 1.11). These data suggest that western gray whales feed primarily in waters less than 20m deep and relatively close to shore. The nutrient-rich effluent from a large coastal lagoon is believed to significantly enrich the near-shore benthic environment of the northeastern Sakhalin Island co...
The Eastern North Pacific gray whale (Eschrichtius robustus) is one population of large cetacean ... more The Eastern North Pacific gray whale (Eschrichtius robustus) is one population of large cetacean that has recovered from depletion resulting from commercial harvest in the mid- to late-1800s. It is believed that this population may be approaching, or possibly exceeding its carrying capacity as suggested by recent increases in mortality of all age and sex classes. Research on the breeding biology and phenology of gray whales that spend the winter in the coastal waters and lagoons of Baja California, Mexico has been conducted for many years. These studies contribute valuable information on the reproductive biology of this species, and the importance of their coastal lagoon habitats to their reproductive success. This paper reviews and summarises historical exploitation, conservation measures, the findings of research conducted on gray whales in their winter breeding range, potential natural and anthropogenic threats to this population, and makes recommendations for future research and...
SUMMARY A Symposium and accompanying workshops were held in Puerto Varas, Chile from 27-29 th Mar... more SUMMARY A Symposium and accompanying workshops were held in Puerto Varas, Chile from 27-29 th March 2012, to discuss recent advances in methods for non-lethal research on whales in the Southern Ocean. The first day (27 th March) was an open Symposium with invited experts who showcased new non-lethal research methods for whales in the Southern Hemisphere. The Symposium was followed by two days of Workshops that covered specific research areas. The Workshops were each one day
Research vessel and aerial platforms were used between 1997 and 2000 to collect genetic and photo... more Research vessel and aerial platforms were used between 1997 and 2000 to collect genetic and photographic data from a small populationof right whales that summers in the southeastern Bering Sea. Totals of 11 and six unique individuals were identified using photographicand genetic methods, respectively. Single matches between years occurred using both methods, and all genetic samples turned out to befrom male whales. Long-term research is needed to estimate the size of this population and to determine what threats the whales may befacing.
The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with ... more The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance pointing at strong gene-tree species tree discordance. Divergence times in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here we used high-coverage whole genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric d...
Proceedings of the Royal Society B: Biological Sciences, 2019
Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but in... more Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to ind...
R. Stone's In Depth News story “Dambuilding threatens Mekong fisheries” (2 December, p. [1084... more R. Stone's In Depth News story “Dambuilding threatens Mekong fisheries” (2 December, p. [1084][1]) explains why the scores of dams planned for the Mekong River are likely to have major impacts on eight of the world's largest freshwater fishes, all of which are already at risk of extinction.
Blue whales in the Northern Indian Ocean are a morphologically and acoustically distinct populati... more Blue whales in the Northern Indian Ocean are a morphologically and acoustically distinct population restricted to these waters. Off Sri Lanka a portion of the population concentrates near shore where they are exposed to a range of anthropogenic threats. We review available data to determine anthropogenic threats/stressors faced by this population and assign subjective rankings for the population-level severity of each threat/stressor based on severity, scope, and immediacy. With the cessation of direct illegal catches on this population in the late 1960s, we ranked ship strike as the most important population-level threat. Incidental catch, which includes entanglement and bycatch, is also important as it can result in death. Other less important stressors that may negatively impact this population include threats resulting from oil and gas development and pollution. However, some stressors can have a long-term cumulative impact that is difficult to assess. The most important researc...
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Papers by Robert Leo Brownell Jr