Kailua-Kona, HI, United States
Kailua-Kona, HI, United States

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Kiszka J.,CNRS Coastal and Marine Environment Laboratory | Oremus M.,University of Auckland | Richard P.,CNRS Coastal and Marine Environment Laboratory | Poole M.,Marine Mammal Research Program | And 2 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2010

Defining trophic relationships among organisms of a community is critical in ecology. However, the access to data is sometimes difficult, particularly in remote environments. Ecological niche segregation among the most common delphinid species was investigated: the spinner dolphin (Stenella longirostris), the roughed-toothed dolphin (Steno bredanensis), the short-finned pilot whale (Globicephala macrorhynchus), and the melon-headed whale (Peponocephala electra). Resource partitioning was explored by analysing δ13C (reflecting foraging habitats) and δ15N stable isotopes (reflecting trophic level) from skin biopsies collected around Moorea from July to October 2002 to 2004. Results revealed that spinner dolphins had the lowest trophic level. The three other species had similar δ15N signatures. The most significant result is the differentiation of S. longirostris from S. bredanensis and G. macrorhynchus but not from the P. electra. For the latter three species, some degrees of overlap were apparent. For S. longirostris, S. bredanensis and G. macrorhynchus, variation of δ13C and δ15N stable isotope was not significant between sexes. This study suggests that stable isotopes reveal some degree of segregation and overlap within this delphinid community. However, fine-scale segregation processes may be concealed by stable isotope analyses, meaning that traditional dietary analyses investigations are complementary in answering questions related to niche segregation. © 2010 Elsevier B.V.


Andrews K.R.,Hawaii Institute of Marine Biology | Andrews K.R.,Marine Mammal Research Program | Karczmarski L.,University of Hong Kong | Karczmarski L.,University of Pretoria | And 6 more authors.
Molecular Ecology | Year: 2010

Spinner dolphins (Stenella longirostris) exhibit different social behaviours at two regions in the Hawaiian Archipelago: off the high volcanic islands in the SE archipelago they form dynamic groups with ever-changing membership, but in the low carbonate atolls in the NW archipelago they form long-term stable groups. To determine whether these environmental and social differences influence population genetic structure, we surveyed spinner dolphins throughout the Hawaiian Archipelago with mtDNA control region sequences and 10 microsatellite loci (n = 505). F-statistics, Bayesian cluster analyses, and assignment tests revealed population genetic separations between most islands, with less genetic structuring among the NW atolls than among the SE high islands. The populations with the most stable social structure (Midway and Kure Atolls) have the highest gene flow between populations (mtDNA ST < 0.001, P = 0.357; microsatellite FST = -0.001; P = 0.597), and a population with dynamic groups and fluid social structure (the Kona Coast of the island of Hawai'i) has the lowest gene flow (mtDNA 0.042 < ST < 0.236, P < 0.05; microsatellite 0.016 < FST < 0.040, P < 0.001). We suggest that gene flow, dispersal, and social structure are influenced by the availability of habitat and resources at each island. Genetic comparisons to a South Pacific location (n = 16) indicate that Hawaiian populations are genetically depauperate and isolated from other Pacific locations (mtDNA 0.216 < FST < 0.643, P < 0.001; microsatellite 0.058 < FST < 0.090, P < 0.001); this isolation may also influence social and genetic structure within Hawai'i. Our results illustrate that genetic and social structure are flexible traits that can vary between even closely-related populations. © 2010 Blackwell Publishing Ltd.


Carroll E.L.,University of St. Andrews | Brooks L.,Southern Cross University of Australia | Baker C.S.,University of Auckland | Baker C.S.,Oregon State University | And 8 more authors.
Endangered Species Research | Year: 2015

Capture-recapture studies offer a powerful tool to assess abundance, survival and population rate of change (γ). A previous capture-recapture study, based on DNA profiles, estimated that the IUCN-listed Endangered Oceania population of humpback whales had a superpopulation size of 4329 whales (95% confidence limits, CL: 3345, 5315) and γ = 1.03 (95% CL: 0.90-1.18) for the period 1999-2005. This low estimate of γ contrasts with the high estimated γ for the neighbouring east Australia population (1.11; 95% CL: 1.105-1.113). A future assessment of Oceania humpbacks through capture-recapture methodology has been proposed to meet 3 objectives: (1) estimate population size with a coefficient of variation of < 20%, and detect if γ is significantly different from (2) 1.00 or (3) γ of east Australia. The proposed survey design involves using DNA profiles to identify whales on principal breeding grounds within Oceania in proportion to the abundance of whales on these grounds over the 10 to 12 wk wintering period, to minimise capture heterogeneity between individuals and to maximise capture probabilities. Simulations of the idealised survey design incorporating data from the previous surveys (1999-2005) with 3 new survey years were conducted under a range of scenarios for the 'true' demographic status of the population. Simulations of the entire Oceania region showed that the proposed design will give sufficient power to meet objectives (1) under all scenarios, (2) if the true γ ≥ 1.05 and (3) if the true γ ≤ 1.05. Region-specific simulations suggested there was scope to test for differences in recovery between principal breeding sites within Oceania. © The authors 2015.


Garland E.C.,University of Queensland | Noad M.J.,University of Queensland | Goldizen A.W.,University of Queensland | Lilley M.S.,IBM | And 6 more authors.
Journal of the Acoustical Society of America | Year: 2013

Humpback whales have a continually evolving vocal sexual display, or "song," that appears to undergo both evolutionary and "revolutionary" change. All males within a population adhere to the current content and arrangement of the song. Populations within an ocean basin share similarities in their songs; this sharing is complex as multiple variations of the song (song types) may be present within a region at any one time. To quantitatively investigate the similarity of song types, songs were compared at both the individual singer and population level using the Levenshtein distance technique and cluster analysis. The highly stereotyped sequences of themes from the songs of 211 individuals from populations within the western and central South Pacific region from 1998 through 2008 were grouped together based on the percentage of song similarity, and compared to qualitatively assigned song types. The analysis produced clusters of highly similar songs that agreed with previous qualitative assignments. Each cluster contained songs from multiple populations and years, confirming the eastward spread of song types and their progressive evolution through the study region. Quantifying song similarity and exchange will assist in understanding broader song dynamics and contribute to the use of vocal displays as population identifiers. © 2013 Acoustical Society of America.


Garland E.C.,University of Queensland | Garland E.C.,South Pacific Whale Research Consortium | Goldizen A.W.,University of Queensland | Rekdahl M.L.,University of Queensland | And 11 more authors.
Current Biology | Year: 2011

Cultural transmission, the social learning of information or behaviors from conspecifics [1-5], is believed to occur in a number of groups of animals, including primates [1, 6-9], cetaceans [4, 10, 11], and birds [3, 12, 13]. Cultural traits can be passed vertically (from parents to offspring), obliquely (from the previous generation via a nonparent model to younger individuals), or horizontally (between unrelated individuals from similar age classes or within generations) [4]. Male humpback whales (Megaptera novaeangliae) have a highly stereotyped, repetitive, and progressively evolving vocal sexual display or "song" [14-17] that functions in sexual selection (through mate attraction and/or male social sorting) [18-20]. All males within a population conform to the current version of the display (song type), and similarities may exist among the songs of populations within an ocean basin [16, 17, 21]. Here we present a striking pattern of horizontal transmission: multiple song types spread rapidly and repeatedly in a unidirectional manner, like cultural ripples, eastward through the populations in the western and central South Pacific over an 11-year period. This is the first documentation of a repeated, dynamic cultural change occurring across multiple populations at such a large geographic scale. © 2011 Elsevier Ltd.


Garland E.C.,University of Queensland | Garland E.C.,South Pacific Whale Research Consortium | Garland E.C.,National Oceanic and Atmospheric Administration | Garland E.C.,University of St. Andrews | And 15 more authors.
Conservation Biology | Year: 2015

For cetaceans, population structure is traditionally determined by molecular genetics or photographically identified individuals. Acoustic data, however, has provided information on movement and population structure with less effort and cost than traditional methods in an array of taxa. Male humpback whales (Megaptera novaeangliae) produce a continually evolving vocal sexual display, or song, that is similar among all males in a population. The rapid cultural transmission (the transfer of information or behavior between conspecifics through social learning) of different versions of this display between distinct but interconnected populations in the western and central South Pacific region presents a unique way to investigate population structure based on the movement dynamics of a song (acoustic) display. Using 11 years of data, we investigated an acoustically based population structure for the region by comparing stereotyped song sequences among populations and years. We used the Levenshtein distance technique to group previously defined populations into (vocally based) clusters based on the overall similarity of their song display in space and time. We identified the following distinct vocal clusters: western cluster, 1 population off eastern Australia; central cluster, populations around New Caledonia, Tonga, and American Samoa; and eastern region, either a single cluster or 2 clusters, one around the Cook Islands and the other off French Polynesia. These results are consistent with the hypothesis that each breeding aggregation represents a distinct population (each occupied a single, terminal node) in a metapopulation, similar to the current understanding of population structure based on genetic and photo-identification studies. However, the central vocal cluster had higher levels of song-sharing among populations than the other clusters, indicating that levels of vocal connectivity varied within the region. Our results demonstrate the utility and value of using culturally transmitted vocal patterns as a way of defining connectivity to infer population structure. We suggest vocal patterns be incorporated by the International Whaling Commission in conjunction with traditional methods in the assessment of structure. © 2015, Society for Conservation Biology.


Wisniewska D.M.,University of Aarhus | Johnson M.,University of St. Andrews | Nachtigall P.E.,Marine Mammal Research Program | Madsen P.T.,University of Aarhus
Journal of Experimental Biology | Year: 2014

Echolocating bats and toothed whales probe their environment with ultrasonic sound pulses, using returning echoes to navigate and find prey in a process that appears to have resulted from a remarkable convergence of the two taxa. Here, we report the first detailed quantification of echolocation behaviour during prey capture in the most studied delphinid species, a false killer whale and a bottlenose dolphin. Using acoustic DTAGs, we demonstrate that just prior to prey interception these delphinids change their acoustic gaze dramatically by reducing inter-click intervals and output >10-fold in a high repetition rate, low output buzz. Buzz click rates of 250-500 Hz for large but agile animals suggest that sampling rates during capture are scaled with the whale's manoeuvrability. These observations support the growing notion that fast sonar sampling accompanied by a low output level is critical for high rate feedback to inform motor patterns during prey interception in all echolocating toothed whales. © 2014. Published by The Company of Biologists Ltd. © 2014. Published by The Company of Biologists Ltd.


PubMed | University of Aarhus, University of St. Andrews and Marine Mammal Research Program
Type: Journal Article | Journal: The Journal of experimental biology | Year: 2014

Echolocating bats and toothed whales probe their environment with ultrasonic sound pulses, using returning echoes to navigate and find prey in a process that appears to have resulted from a remarkable convergence of the two taxa. Here, we report the first detailed quantification of echolocation behaviour during prey capture in the most studied delphinid species, a false killer whale and a bottlenose dolphin. Using acoustic DTAGs, we demonstrate that just prior to prey interception these delphinids change their acoustic gaze dramatically by reducing inter-click intervals and output >10-fold in a high repetition rate, low output buzz. Buzz click rates of 250-500 Hz for large but agile animals suggest that sampling rates during capture are scaled with the whales manoeuvrability. These observations support the growing notion that fast sonar sampling accompanied by a low output level is critical for high rate feedback to inform motor patterns during prey interception in all echolocating toothed whales.


Albertson G.R.,Oregon State University | Baird R.W.,Cascadia Research Collective Olympia | Oremus M.,British Petroleum | Poole M.M.,Marine Mammal Research Program | And 3 more authors.
Conservation Genetics | Year: 2016

Rough-toothed dolphins have a worldwide tropical and subtropical distribution, yet little is known about the population structure and social organization of this typically open-ocean species. Although it has been assumed that pelagic dolphins range widely due to the lack of apparent barriers and unpredictable prey distribution, recent evidence suggests rough-toothed dolphins exhibit fidelity to some oceanic islands. Using the most comprehensively extensive dataset for this species to date, we assess the isolation and interchange of rough-toothed dolphins at the regional and oceanic scale within the central Pacific Ocean. Using mtDNA and microsatellite genotyping (nDNA), we analyzed samples of insular communities from the main Hawaiian (Kaua‘i n = 93, O‘ahu n = 9, Hawai‘i n = 57), French Polynesian (n = 70) and Samoan (n = 16) archipelagos, and pelagic samples off the Northwestern Hawaiian Islands (n = 18). An overall AMOVA indicated strong genetic differentiation among islands (mtDNA FST = 0.265; p < 0.001; nDNA FST = 0.038; p < 0.001), as well as among archipelagos (mtDNA FST = 0.299; p < 0.001; nDNA FST = 0.055; p < 0.001). Shared haplotypes (n = 4) between the archipelagos may be a product of a relatively recent divergence and/or periodic exchange from poorly understood pelagic populations. Analyses using STRUCTURE and GENELAND identified four separate management units among archipelagos and within the Hawaiian Islands. These results confirm the presence of multiple insular populations within the Pacific and island-specific genetic isolation among populations attached to islands in each archipelago. Insular populations seem most prevalent where oceanographic conditions indicate high local productivity or a discontinuity with surrounding oligotrophic areas. Our findings have important implications for a little studied species that faces increasing anthropogenic threats around oceanic islands. © 2016 Springer Science+Business Media Dordrecht


Oremus M.,University of Auckland | Oremus M.,British Petroleum | Poole M.M.,Marine Mammal Research Program | Albertson G.R.,Oregon State University | And 2 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2012

Pelagic species of dolphins are generally assumed to be nomadic, while coastal/insular species often show strong site fidelity. Rough-toothed dolphins (Steno bredanensis) are characteristically described as pelagic, but studies based on individual identification have shown some level of site fidelity near oceanic islands. Here, we collected photographs for individual identification (n=108 unique individuals) and biopsy samples (n=64) to assess genetic diversity, population structure and abundance of rough-toothed dolphins around Moorea and Raiatea (170km apart) in the Society Islands, French Polynesia. Genotype (14 microsatellite loci) and photo-identification recaptures over two to 12years indicated long-term site fidelity around Moorea and a high probability of demographic partitioning between Moorea and Raiatea. There was also a marked genetic differentiation between the two islands for both control region mitochondrial haplotypes (450 base pairs, FST=0.58, p<0.001) and microsatellite allele frequencies (FST=0.07, p<0.001), a pattern confirmed by Bayesian clustering analysis. Around Moorea, estimates of census and current effective population size support a population size in the low hundreds. These results suggest a pattern of small, resident community structure, raising important implications for the management of this species known for depredation issues with local fisheries. Such pattern may be found in other species of pelagic dolphins around oceanic islands, extending the need to conduct similar studies in order to highlight potential conservation issues. © 2012 Elsevier B.V.

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