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1.
Managing escalating human impacts on nearshore cetaceans requires information on a species' demography and distribution patterns at appropriate spatial scales. Identification photographs of individuals of a population of inshore Indo-Pacific bottlenose dolphins, Tursiops aduncus , were obtained in the open coastal waters off North Stradbroke Island, Australia and used to estimate population density and residency. Five hundred and eighty-one individuals were identified from 342 school sightings during 1998 and 1999. Mark-recapture analysis using closed population models estimated a population size of between 700 and 1,000 individuals within the study area during winter, with evidence that the population contained resident individuals. This represents an extremely high number of dolphins within a small area, which requires a pre-emptive management strategy to ensure their continued occupancy. 相似文献
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This study estimates the population size of Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) in the Algoa Bay region on the Eastern Cape coast of South Africa. Mark-recapture analyses were performed on photo-identification data collected on 54 occasions during a 3-yr-study period. Using a photographic data set of over 10,000 ID-images, 1,569 individuals were identified, 131 of which were photographed on more than one occasion. Using the POPAN formulation in the software program MARK, a total population of approximately 28,482 individuals (95% CI = 16,220–40,744; CV = 0.220), was estimated (estimate corrected for the proportion of distinctive individuals in the population). This is the largest population estimate to date for this species along the South African coast, suggesting that the bottlenose dolphins inhabiting the Algoa Bay region represent part of a substantially larger population that ranges along a considerable length of the South African coast. 相似文献
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Anna Särnblad Magnus Danbolt Love Dalén Omar A. Amir Per Berggren 《Marine Mammal Science》2011,27(2):431-448
Phylogenetic placement of bottlenose dolphins from Zanzibar, East Africa and putative population differentiation between animals found off southern and northern Zanzibar were examined using variation in mtDNA control region sequences. Samples (n= 45) from animals bycaught in fishing gear and skin biopsies collected during boat surveys were compared to published sequences (n= 173) of Indo‐Pacific bottlenose dolphin, Tursiops aduncus, from southeast Australian waters, Chinese/Indonesian waters, and South African waters (which recently was proposed as a new species) and to published sequences of common bottlenose dolphin, Tursiops truncatus. Bayesian and maximum parsimony analyses indicated a close relationship between Zanzibar and South African haplotypes, which are differentiated from both Chinese/Indonesian and Australian T. aduncus haplotypes. Our results suggest that the dolphins found off Zanzibar should be classified as T. aduncus alongside the South African animals. Further, analyses of genetic differentiation showed significant separation between the T. aduncus found off northern and southern Zanzibar despite the relatively short distance (approximately 80 km) between these areas. Much less differentiation was found between southern Zanzibar and South Africa, suggesting a more recent common evolutionary history for these populations than for the northern and southern Zanzibar populations. 相似文献
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Caroline Rinaldi Renato Rinaldi Juliette Laine Christophe Barbraud 《Marine Mammal Science》2021,37(4):1391-1405
Sperm whales are present along the Caribbean islands in family groups of mature females, juveniles, and newborns. Their abundance and demographic rates remain poorly known. Using photo-identification data, we estimated the abundance and annual survival of sperm whales in Guadeloupe from January to April 2001–2013. A total of 1,492 photographs of tail flukes were scored (ranging from 1 to 5) in terms of quality (Q) and marking (M) level. A total of 789 photographs were selected with Q ≥ 3 and M ≥ 3, corresponding to 109 individually identified adult females or immatures of both sexes. Capture histories were built and analyzed using the Pollock's robust design capture-mark-recapture model. The study consisted of 13 primary periods sequenced in 5–8 secondary periods. Mean annual survival rate of residents was 0.945, 95% CI [0.864, 0.979]. Abundance varied between years from 75 to 35 individuals. The geometric growth rate over the period 2001–2013 was 0.938, 95% CI [0.878, 0.997], suggesting a population decline of −6.2%/year. Sperm whales are moving between Guadeloupe and Dominica, with a high temporary emigration rate (0.163) and 50% of the individuals of Guadeloupe resighted in Dominica. These results highlight the fragility of the population and the necessity to consider it as one unit. 相似文献
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Oliver Manlik Delphine Chabanne Claire Daniel Lars Bejder Simon J. Allen William B. Sherwin 《Marine Mammal Science》2019,35(3):732-759
The forecast for the viability of populations depends upon metapopulation dynamics: the combination of reproduction and mortality within populations, as well as dispersal between populations. This study focuses on an Indo‐Pacific bottlenose dolphin (Tursiops aduncus) population in coastal waters near Bunbury, Western Australia. Demographic modeling of this population suggested that recent reproductive output was not sufficient to offset mortality. Migrants from adjacent populations might make up this deficit, so that Bunbury would act as a “sink,” or net recipient population. We investigated historical dispersal in and out of Bunbury, using microsatellites and mitochondrial DNA of 193 dolphins across five study locations along the southwestern Australian coastline. Our results indicated limited gene flow between Bunbury and adjacent populations. The data also revealed a net‐dispersal from Bunbury to neighboring populations, with microsatellites showing that more than twice as many individuals per generation dispersed out of Bunbury than into Bunbury. Therefore, in historic times, Bunbury appears to have acted as a source population, supporting nearby populations. In combination with the prior finding that Bunbury is currently not producing surplus offspring to support adjacent populations, this potential reversal of source‐sink dynamics may have serious conservation implications for Bunbury and other populations nearby. 相似文献
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Judith Denkinger Daniela Alarcon Bitinia Espinosa Lynn Fowler Cindy Manning Javier Oña Daniel M. Palacios 《Marine Mammal Science》2020,36(3):774-785
Killer whales (Orcinus orca) have strong social matrilineal bonds and form groups and long-lasting associations, but little is known about their population or social structure in an equatorial setting such as the waters around the Galápagos Islands. Using 91 encounters and identification photographs from 1991 to 2017, we identified 64 killer whales of which 18 individuals were locals with high resighting rates. Group size was small, ranging from 1 to 15 animals, with 69% of the groups containing four or fewer animals. Using social network analysis (SOCPROG 2.7) whales grouped into three distinct units and one loose association with frequent exchange between different groups. One male–male unit showed a strong association (association strength = 0.55). Overall, associations lasted over at least 3 years. Our data give first evidence of a loose social organization of Galápagos killer whales, similar to fission-fusion societies. 相似文献
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Kazunobu Kogi Toru Hishii Ayami Imamura Takako Iwatani Kathleen M. Dudzinski 《Marine Mammal Science》2004,20(3):510-526
Long-term identification surveys were conducted using video records on Indo-Pacific bottlenose dolphin ( Tursiops aduncus ) around Mikura Island, Tokyo, Japan. On 246 surveys, 3,996 min of video were recorded during each summer season from 1994 to 2001. Two hundred and twenty individuals were observed, including juveniles and neonates, that were not cataloged, but could be identified by association with their mothers. Over the eight-year study period, the total number of identified and cataloged individuals was 169. The annual number of newly identified dolphins stabilized at ∼ 10 after 1995. In the middle of each research season, a plateau in the number of reidentified individuals was reached. Most of the dolphins were observed frequently–percentages of reidentified dolphins in adjoining years were greater than 86% and 62 individuals were seen consecutively during the eight years. There were no significant differences in the sex ratio between years. The sex ratio was skewed significantly towards male for subadults and towards female for adults. The survival rate of one-year-old calves was 86.7%, and the mean age at weaning was 3.5 yr. The calving interval averaged 3.4 yr among adult females. The mean annual birth, fecundity, and recruitment rates were 0.071, 0.239, and 0.068, respectively. Mikura Island is located in the pelagic ocean with no protected bay area existing around the island. Dolphins do not regularly inhabit any other locations besides Mikura within the Izu island chain. Thus, this island may be important core habitat of these dolphins. 相似文献
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We isolated and characterized 19 novel tetranucleotide microsatellite markers in the Indo-Pacific bottlenose dolphin (Tursiops aduncus) in order to improve genotyping accuracy in applications like large-scale population-wide paternity and relatedness assessments. One hundred T. aduncus from Shark Bay, Western Australia, were screened for polymorphism. Cross-amplification was tested on four other small odontocete species. The new tetranucleotide microsatellite loci showed a more than fourfold higher scoring accuracy and significantly lower stutter formation compared to eight dinucleotide loci, although overall allelic diversity was significantly reduced. 相似文献
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应用标志－释放－回收技术研究小皱蝽成虫的主要种群特征,结果如下：（１）成虫扩散的偏离度Ｋｕ＝２．４,为一阶峻开曲线;（２）分别用Ｐｅｔｅｒｓｏｎ和Ｊａｃｋｓｏｎ方法对种群蜜度进行了估计,结果表明,Ｊａｃｋｓｏｎ的方法较好;（３）雄虫平均寿命４０－４５,虫平均寿命１２０－１３０。天。 相似文献
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Critical conservation decisions often hinge on estimates of population size, population growth rate, and survival rates, but as a practical matter it is difficult to obtain enough data to provide precise estimates. Here we discuss Bayesian methods for simultaneously drawing on the information content from multiple sorts of data to get as much precision as possible for the estimates. The basic idea is that an underlying population model can connect the various sorts of observations, so this can be elaborated into a joint likelihood function for joint estimation of the respective parameters. The potential for improved estimates derives from the potentially greater effective sample size of the aggregate of data, even though some of the data types may only bear directly on a subset of the parameters. The achieved improvement depends on specifics of the interactions among parameters in the underlying model, and on the actual content of the data. Assuming the respective data sets are unbiased, notwithstanding the fact that they may be noisy, we may gauge the average improvement in the estimates of the parameters of interest from the reduction, if any, in the standard deviations of their posterior marginal distributions. Prospective designs may be evaluated from analysis of simulated data. Here this approach is illustrated with an assessment of the potential value in various ways of merging mark-resight and carcass-survey data for the Florida manatee, as could be made possible by various modifications in the data collection protocols in both programs. 相似文献
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The use of natural marks in capture-recapture studies can lead to unequal capture probabilities. This paper examined a catalog of northern bottlenose whale ( Hyperoodon ampullatus ) photographs from the Gully, Nova Scotia, to identify potential sources of heterogeneity. This information can be used to select appropriate individuals and photographs to include in analyses. Individual northern bottlenose whales were sufficiently marked to uniquely identify individuals (= 14.5 marks/individual; range 1-67), but not all mark types persisted over time. Reliable marks were defined as mark types that were not lost over the nine-yeat study period (notches, back indentation, and mottled patches). Individuals were considered reliably marked if they possessed at least one back indentation or mottled patch (located within one dorsal fin width, at the base of the dorsal fin) or a notch on the dorsal fin. Sixty-six percent (SE = 5%) of the population were reliably marked. Longterm analyses (months to years) should use only reliably marked individuals, and the results scaled to account for the rest of the population. Our results also showed that photographic quality affected an observer's ability to identify individuals. For this catalog, quantitative analysis indicated only photographs of Q ≥ 4 (on a 6-point scale with 6 representing the highest quality) should be included in mark-recapture analyses sensitive to heterogeneity. 相似文献
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Sequence analysis of the mitochondrial DNA control region was used to clarify the taxonomic status of two coastal bottlenose dolphin populations from southeastern Australia currently classified as Tursiops truncatus . A 368-bp segment of the control region of 57 biopsy-sampled, photo-identified dolphins of Jervis Bay and Port Stephens was compared to published sequences of T. truncatus and T. aduncus from different oceanic regions. Sequence divergence between haplotypes from southeastern Australia and T. aduncus was much lower than that from T. truncatus . Analyses using two different methods of phylogenetic reconstruction unambiguously placed all haplotypes from southeastern Australia in a group composed exclusively of T. aduncus . The results strongly indicated that these two bottlenose dolphin populations belong to T. aduncus , extending the range of the species to subtropical waters of the Western South Pacific Ocean. 相似文献
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We assessed information on the population structure of the nurse shark, Ginglymostoma cirratum, at Atol das Rocas, northeastern Brazil, through underwater observations. Based on photographic records of natural distinctive marks for individual recognition, we used probabilistic estimators (Petersen–Bailey and Jolly–Seber) to assess population size. We found that 46% of the sharks (194 individuals) had distinctive marks. The population size was estimated in 368 individuals, using the Petersen–Bailey estimator, and 339 individuals using the Jolly–Seber estimator. 相似文献
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Akihiko Suzuki Koyuki Akuzawa Kazunobu Kogi Keiichi Ueda Miwa Suzuki 《Marine Mammal Science》2021,37(1):207-219
Captive environments impact the microbiota of captive animals; however, the comparison of microbiota between wild and captive dolphins has been poorly investigated. To explore the impact of a captive environment, we characterized the fecal microbiota of nine wild and four captive Indo-Pacific bottlenose dolphins, Tursiops aduncus, using a next-generation sequencing and revealed differences in the fecal microbiota between the analyzed groups. Statistical differences in abundances of the phyla Firmicutes and Proteobacteria were found between the wild and captive dolphins. Thirty-six genera (22.9% of the total genera detected in all dolphins) were shared between the groups, whereas 79 (50.3%) and 42 (26.8%) genera were found only in the wild or captive dolphins, respectively. Several pathogenic bacterial genera, including Morganella and Mycoplasma, were detected only in the captive dolphins, and the genus Lactobacillus was found only in the wild dolphins. LefSe and SIMPER analyses revealed that the genus Clostridium sensu stricto 1 was significantly more abundant in the captive dolphins than in the wild ones and contributed the most to the dissimilarity of fecal microbiota between the groups. Our results indicate that the captive environment impacts the fecal microbiota of dolphins and reinforces the importance of monitoring potentially pathogenic bacteria in captivity. 相似文献
16.
Lorenzo Garizio;Marco Gargano;Giuliano Colosimo;Paolo Gratton;Glenn Philip Gerber;Gregory Lewbart;Christian Sevilla;Gabriele Gentile; 《Conservation Science and Practice》2024,6(4):e13108
We present the first estimate of population dynamics parameters for critically endangered Galápagos pink land iguanas, Conolophus marthae, leveraging mark-recapture data collected between 2006 and 2021. Demographic parameters were estimated using the POPAN formulation of the Jolly–Seber model. This approach provided a solid and robust estimate, consolidating the results obtained from previous estimates based on the Lincoln–Petersen method evaluating only two sampling occasions. Our results suggest that the abundance of males was higher than that of females at each sampling occasion, probably due to differences in sex-specific behavior during the reproductive season. Our analyses also provide no evidence of a change in population size during the sampling period, estimated at 150–270 adult individuals, while suggesting positive entry rates. Finally, by comparing the biometric features of first-captured versus recaptured iguanas, we found that the former have more juvenile-like characteristics (i.e., they are, on average, smaller) than the latter. Although juvenile pink iguanas have rarely been recorded (only four sampled juvenile-like individuals in over 16 years of field work), our combined results provide the first clear indication that the only known C. marthae population actively recruits new members from younger age classes. Such recruitment may have prevented any measurable population decline in the last 16 years, but it was also not sufficient to clearly increase the population size. These results are of the utmost importance for the conservation of this species. They will guide future high-priority actions: (i) aiming at increasing population size by removing or mitigating threats and (ii) increasing the number of individuals by implementing a headstart program and/or founding a second viable population, as identified in the recently published IUCN Conservation and Management Plan. 相似文献
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This study represents the first comprehensive assessment of the population dynamics and residency of common bottlenose dolphin around Reunion Island (southwest Indian Ocean). Understanding dynamics and movement patterns of this local population is essential to guide effective conservation efforts, notably in a context of growing dolphin-watching activities. Dedicated surveys based on photo-identification methods were conducted over 6 years (2010–2015). The species was present year-round, in groups of 25 individuals on average (1–150). Jolly-Seber mark-recapture models resulted in a population estimate of 254 individuals (95% CI = 191–337) and an apparent annual survival rate of 0.83. The population was almost equally split into three residency patterns: residents (33.1%), long-term visitors (32.6%), and short-term visitors (34.3%, including transients, i.e., individuals only seen once [14.9%]), suggesting that the majority of the population showed a moderate-to-high level of residency in the study area. Individuals from the three residency patterns associated randomly, mixing together and forming a single community. Models based on the lagged identification rate indicated emigration and reimmigration to the survey area, with some individuals occupying the study area for about 2 years (832 days), and remaining outside for an average of 276 days, probably exhibiting larger home ranges and extensive movement behavior. 相似文献
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【目的】明确黑翅土白蚁Odontotermes formosanus巢群的觅食群体大小与工蚁体长之间的关系,为进一步研究其生态学特点以及更好地开展防治提供依据。【方法】在杭州植物园内选择5处有黑翅土白蚁活动区域作试验点,诱捕并以中性红(neutral red)标记捕获的白蚁工蚁,通过“捕获-标记-释放-重捕”试验测定黑翅土白蚁的觅食群体大小。【结果】5个试验点中有4个成功实施了“捕获-标记-释放-重捕”试验,4个试验点黑翅土白蚁巢群的觅食群体个体数量分别为443 133±45 469, 495 360±67 429, 674 345±101 703和1 224 662±93 112头。黑翅土白蚁觅食群体大小(Y)与觅食工蚁的体长(X)呈正相关,拟合的指数函数方程式为：Y=1.8389e0.7185X(R2=0.7834)。【结论】本研究明确了黑翅土白蚁的觅食群体大小以及工蚁体长之间的函数关系,为开展区域防治提供了依据。 相似文献
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The aim of this study was to assess potential impacts of water quality changes associated with floods on the occupancy of Indo‐Pacific bottlenose dolphins (Tursiops aduncus) in two subtropical estuaries in Australia. Boat‐based surveys were conducted in the Clarence River estuary (CR) and Richmond River estuaries (RR) over 3 yr. Principal components analysis (PCA) showed that when the dolphins were absent from the estuaries, three water quality components were extracted in the CR and two components in the RR. The PCA1 component included high loadings for salinity, turbidity, and pH for the CR (46%); and salinity, turbidity, pH, and dissolved oxygen (DO) for the RR (51%). Randomization tests showed that dolphins abandoned both estuaries at times of lower salinity, and during periods of higher turbidity and of lower levels of pH and dissolved oxygen in the RR that were associated with floods. The time until dolphins returned to the estuary postflood depended on the length and severity of the flood, but generally dolphins were observed in waters with salinity levels above 29‰. Their delayed return postflood could be for their physiological health, or because their prey returned to the estuaries under these higher salinity conditions, or more likely a combination of both factors. 相似文献