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Guang Yang - One of the best experts on this subject based on the ideXlab platform.

  • high level population differentiation of finless porpoises Neophocaena phocaenoides in chinese waters revealed by sequence variability of four nuclear introns
    Molecular Biology Reports, 2012
    Co-Authors: Jianfeg Ju, Shixia Xu, Kaiya Zhou, Mei Yang, Guang Yang
    Abstract:

    In the present study, sequence variations at four nuclear introns which were respectively from the parathyroid hormone-like (PTH) gene, isolate Pdalz1692 interferon (IFN) gene, peripherin-like (RDS) gene, and tyrosine kinase receptor-like (KIT) gene, were examined to analyze genetic diversity and population structure of the finless porpoise (Neophocaena phocaenoides) in Chinese waters. High among-population differentiation was revealed, with a significant genetic structure between populations (PTH: FST = 0.29, P < 0.001; IFN1@: FST = 0.23, P < 0.001; RDS: FST = 0.12, P < 0.001; KIT: FST = 0.16, P < 0.001) shown by the analysis of molecular variance. Although common haplotypes accounted for more than one half of all samples examined, many haplotypes were found to be population-specific. The Tajima’s D, Fu’s tests and mismatch distributions all suggested a recent colonization and population expansion of finless porpoises in Chinese waters. In view of special reference to the conservation priority of the Yangtze finless porpoises, special protection measures must be taken urgently for this population.

  • sequence polymorphism and geographical variation at a positively selected mhc drb gene in the finless porpoise Neophocaena phocaenoides implication for recent differentiation of the yangtze finless porpoise
    Journal of Molecular Evolution, 2010
    Co-Authors: Shixia Xu, Kaiya Zhou, Xuming Zhou, Guang Yang
    Abstract:

    Sequence polymorphism at the MHC class II DRB locus was investigated in three finless porpoise (Neophocaena phocaenoides) populations in Chinese waters. Intragenic recombination and strong positive selection were the main forces in generating sequence diversity in the DRB gene. MHC sequence diversity changed significantly along the study period. Significant decrease in heterozygosity and lost alleles have been detected in the Yangtze River population and South China Sea population since 1990. Furthermore, there is a trend of increasing population differentiation over time. Especially, the genetic differentiation between the Yangtze River population and the Yellow Sea population was very low prior to 1990 (FST = 0.036, P = 0.009), but became very significant after 1990 (FST = 0.134, P < 0.001), suggesting a recent augmentation of genetic differentiation between both populations probably in a relatively short-term period. Porpoises from the Yangtze River displayed divergent frequencies of shared and private alleles from those displayed by two marine populations, which suggest that the former riverine population has been under a different selection regime (characteristic of a fresh water environment) than that of its marine counterparts.

  • microsatellite variation and significant population genetic structure of endangered finless porpoises Neophocaena phocaenoides in chinese coastal waters and the yangtze river
    Marine Biology, 2010
    Co-Authors: Lian Chen, Guang Yang, Michael William Bruford, Kaiya Zhou, Shixia Xu
    Abstract:

    The finless porpoise (Neophocaena phocaenoides) inhabits a wide range of tropical and temperate waters of the Indo-Pacific region. Genetic structure of finless porpoises in Chinese waters in three regions (Yangtze River, Yellow Sea, and South China Sea) was analyzed, including the Yangtze finless porpoise which is widely known because of its highly endangered status and unusual adaptation to freshwater. To assist in conservation and management of this species, ten microsatellite loci were used to genotype 125 individuals from the three regions. Contrary to the low genetic diversity revealed in previous mtDNA control region sequence analyses, relatively high levels of genetic variation in microsatellite profiles (H E = 0.732–0.795) were found. Bayesian clustering analysis suggested that finless porpoises in Chinese waters could be described as three distinct genetic groups, which corresponded well to population “units” (populations, subspecies, or species) delimited in earlier studies, based on morphological variation, distribution, and genetic analyses. Genetic differentiation between regions was significant, with F ST values ranging from 0.07 to 0.137. Immigration rates estimated using a Bayesian method and population ancestry analyses suggested no or very limited gene flow among regional types, even in the area of overlap between types. These results strongly support the classification of porpoises in these regions into distinct evolutionarily significant units, including at least two separate species, and therefore they should be treated as different management units in the design and implementation of conservation programmes.

  • snp discovery based on cats and genotyping in the finless porpoise Neophocaena phocaenoides
    Conservation Genetics, 2009
    Co-Authors: Shuzhen Li, Heyi Ji, Kaiya Zhou, Guang Yang
    Abstract:

    Single nucleotide polymorphisms (SNPs) discovery and genotyping were performed for the finless porpoises (Neophocaena phocaenoides). About 202 comparative anchor tagged sequence primers derived from genomes of human, mouse and some other mammals were used to screen the finless porpoise population. Of the 51 SNPs discovered, 25 were further characterized with ideal genotyping primers and using fragment length discrepant allele specific PCR assay. This is the first report of SNP loci for the finless porpoise, which is helpful to provide some novel molecular markers and new genetic information relevant to the conservation and management of this endangered species.

  • development of tetranucleotide microsatellite loci for the finless porpoise Neophocaena phocaenoides
    Conservation Genetics, 2008
    Co-Authors: Lian Chen, Guang Yang
    Abstract:

    The finless porpoise, Neophocaena phocaenoides, is endemic to the coastal waters of the Indo-Pacific, ranging from the Persian Gulf to Japan. Nine tetranucleotide microsatellite loci were isolated from the finless porpoise (Neophocaena phocaenoides). Polymorphism of each locus was assessed in 39 unrelated individuals from the Yellow Sea and the South China Sea of the Chinese waters. The number of alleles per locus varied from 2 to 11. The ranges of observed and expected heterozygosity were 0.154–0.795 and 0.146–0.839, respectively. Cross-species amplification of these loci was tested in other cetacean species. These microsatellite markers described here will be suitable for population genetic studies of finless porpoises and other cetacean species.

Ding Wang - One of the best experts on this subject based on the ideXlab platform.

  • Nonconstant quality of auditory filters in the porpoises, Phocoena phocoena and Neophocaena phocaenoides (Cetacea, Phocoenidae).
    The Journal of the Acoustical Society of America, 2020
    Co-Authors: Vladimir V Popov, Alexander Ya Supin, Ding Wang, Kexiong Wang
    Abstract:

    Simultaneous tone-tone masking in conjunction with the envelope-following response (EFR) recording was used to obtain tuning curves in porpoises Phocoena phocoena and Neophocaena phocaenoides asiaeorientalis. The EFR was evoked by amplitude-modulated probes with a modulation rate of 1000 Hz and carrier frequencies from 22.5 to 140 kHz. Equivalent rectangular quality QERB of the obtained tuning curves varied from 8.3-8.6 at lower (22.5-32 kHz) probe frequencies to 44.8-47.4 at high (128-140 kHz) frequencies. The QERB dependence on probe frequency could be approximated by regression lines with a slope of 0.83 to 0.86 in log-log scale, which corresponded to almost frequency-proportional quality and almost constant bandwidth of 3-4 kHz. Thus, the frequency representation in the porpoise auditory system is much closer to a constant-bandwidth rather that to a constant-quality manner.

  • analysis of the bacterial diversity in the fecal material of the endangered yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis
    Molecular Biology Reports, 2012
    Co-Authors: Jinsong Zheng, Qingzhong Zhao, Richard William Mclaughlin, Minmin Chen, Ding Wang
    Abstract:

    The aim of this study was to determine the bacteria present in the fecal material of the endangered Yangtze finless porpoise, Neophocaena phocaenoides asiaeorientalis. Fecal samples were collected from 12 Yangtze finless porpoises living in the wild at Poyang Lake, located in Jiangxi Province, China. To determine the bacterial diversity, a 16S rRNA gene clone library using the bacterial PCR primers fD1 and rP2, was prepared. A total of 138 near-full-length sequences were analyzed and 39 operational taxonomic units (OTUs) were identified. Sequences showing ≥97% similarity were grouped together as an OTU. Six different phyla were identified in which 38 OTUs were classified. Most of the OTUs contained sequences belonged to the phylum Firmicutes (51.3%), followed by Tenericutes (17.9%), Proteobacteria (15.4%), Actinobacteria (7.7%), Deinococcus-Thermus (2.6%) and Cyanobacteria (2.6%). A phylum could not be assigned for one clone within one OTU (2.6%). It appears that the Yangtze finless porpoise has a more diverse range of bacteria compared to other aquatic mammals, such as seals.

  • herpes like virus infection in yangtze finless porpoise Neophocaena phocaenoides pathology ultrastructure and molecular analysis
    Journal of Wildlife Diseases, 2012
    Co-Authors: Xiuping Yuan, Ding Wang, Qingzhong Zhao, Qiya Zhang
    Abstract:

    A moribund juvenile Yangtze finless porpoise (Neophocaena phocaenoides) with skin lesions and ulceration was found in Dongting Lake, China. Pathologic examination, electron microscopy, and polymerase chain reaction of liver tissue revealed widely distributed necrotic lesions, sinusoidal dilatation, congestion and herpes-like virus particles.

  • auditory temporal resolution and evoked responses to pulsed sounds for the yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis
    Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2011
    Co-Authors: Aran T Mooney, Kexiong Wang, Songhai Li, Darlene R Ketten, Ding Wang
    Abstract:

    Temporal cues are important for some forms of auditory processing, such as echolocation. Among odontocetes (toothed whales, dolphins, and porpoises), it has been suggested that porpoises may have temporal processing abilities which differ from other odontocetes because of their relatively narrow auditory filters and longer duration echolocation signals. This study examined auditory temporal resolution in two Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) using auditory evoked potentials (AEPs) to measure: (a) rate following responses and modulation rate transfer function for 100 kHz centered pulse sounds and (b) hearing thresholds and response amplitudes generated by individual pulses of different durations. The animals followed pulses well at modulation rates up to 1,250 Hz, after which response amplitudes declined until extinguished beyond 2,500 Hz. The subjects had significantly better hearing thresholds for longer, narrower-band pulses similar to porpoise echolocation signals compared to brief, broadband sounds resembling dolphin clicks. Results indicate that the Yangtze finless porpoise follows individual acoustic signals at rates similar to other odontocetes tested. Relatively good sensitivity for longer duration, narrow-band signals suggests that finless porpoise hearing is well suited to detect their unique echolocation signals.

  • noise induced temporary threshold shift and recovery in yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis
    Journal of the Acoustical Society of America, 2011
    Co-Authors: V V Popov, Kexiong Wang, Lijun Dong, Ding Wang, Alexander Ya Supin, Shiyong Wang
    Abstract:

    In Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis, the effects of fatiguing noise on hearing thresholds at frequencies of 32, 45, 64, and 128 kHz were investigated. The noise parameters were: 0.5-oct bandwidth, -1 to +0.5 oct relative to the test frequency, 150 dB re 1 mu Pa (140-160 dB re 1 mu Pa in one measurement series), with 1-30 min exposure time. Thresholds were evaluated using the evoked-potential technique allowing the tracing of threshold variations with a temporal resolution better than 1 min. The most effective fatiguing noise was centered at 0.5 octave below the test frequency. The temporary threshold shift (TTS) depended on the frequencies of the fatiguing noise and test signal: The lower the frequencies, the bigger the noise effect. The time-to-level trade of the noise effect was incomplete: the change of noise level by 20 dB resulted in a change of TTS level by nearly 20 dB, whereas the tenfold change of noise duration resulted in a TTS increase by 3.8-5.8 dB. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3596470]

Kaiya Zhou - One of the best experts on this subject based on the ideXlab platform.

  • high level population differentiation of finless porpoises Neophocaena phocaenoides in chinese waters revealed by sequence variability of four nuclear introns
    Molecular Biology Reports, 2012
    Co-Authors: Jianfeg Ju, Shixia Xu, Kaiya Zhou, Mei Yang, Guang Yang
    Abstract:

    In the present study, sequence variations at four nuclear introns which were respectively from the parathyroid hormone-like (PTH) gene, isolate Pdalz1692 interferon (IFN) gene, peripherin-like (RDS) gene, and tyrosine kinase receptor-like (KIT) gene, were examined to analyze genetic diversity and population structure of the finless porpoise (Neophocaena phocaenoides) in Chinese waters. High among-population differentiation was revealed, with a significant genetic structure between populations (PTH: FST = 0.29, P < 0.001; IFN1@: FST = 0.23, P < 0.001; RDS: FST = 0.12, P < 0.001; KIT: FST = 0.16, P < 0.001) shown by the analysis of molecular variance. Although common haplotypes accounted for more than one half of all samples examined, many haplotypes were found to be population-specific. The Tajima’s D, Fu’s tests and mismatch distributions all suggested a recent colonization and population expansion of finless porpoises in Chinese waters. In view of special reference to the conservation priority of the Yangtze finless porpoises, special protection measures must be taken urgently for this population.

  • sequence polymorphism and geographical variation at a positively selected mhc drb gene in the finless porpoise Neophocaena phocaenoides implication for recent differentiation of the yangtze finless porpoise
    Journal of Molecular Evolution, 2010
    Co-Authors: Shixia Xu, Kaiya Zhou, Xuming Zhou, Guang Yang
    Abstract:

    Sequence polymorphism at the MHC class II DRB locus was investigated in three finless porpoise (Neophocaena phocaenoides) populations in Chinese waters. Intragenic recombination and strong positive selection were the main forces in generating sequence diversity in the DRB gene. MHC sequence diversity changed significantly along the study period. Significant decrease in heterozygosity and lost alleles have been detected in the Yangtze River population and South China Sea population since 1990. Furthermore, there is a trend of increasing population differentiation over time. Especially, the genetic differentiation between the Yangtze River population and the Yellow Sea population was very low prior to 1990 (FST = 0.036, P = 0.009), but became very significant after 1990 (FST = 0.134, P < 0.001), suggesting a recent augmentation of genetic differentiation between both populations probably in a relatively short-term period. Porpoises from the Yangtze River displayed divergent frequencies of shared and private alleles from those displayed by two marine populations, which suggest that the former riverine population has been under a different selection regime (characteristic of a fresh water environment) than that of its marine counterparts.

  • microsatellite variation and significant population genetic structure of endangered finless porpoises Neophocaena phocaenoides in chinese coastal waters and the yangtze river
    Marine Biology, 2010
    Co-Authors: Lian Chen, Guang Yang, Michael William Bruford, Kaiya Zhou, Shixia Xu
    Abstract:

    The finless porpoise (Neophocaena phocaenoides) inhabits a wide range of tropical and temperate waters of the Indo-Pacific region. Genetic structure of finless porpoises in Chinese waters in three regions (Yangtze River, Yellow Sea, and South China Sea) was analyzed, including the Yangtze finless porpoise which is widely known because of its highly endangered status and unusual adaptation to freshwater. To assist in conservation and management of this species, ten microsatellite loci were used to genotype 125 individuals from the three regions. Contrary to the low genetic diversity revealed in previous mtDNA control region sequence analyses, relatively high levels of genetic variation in microsatellite profiles (H E = 0.732–0.795) were found. Bayesian clustering analysis suggested that finless porpoises in Chinese waters could be described as three distinct genetic groups, which corresponded well to population “units” (populations, subspecies, or species) delimited in earlier studies, based on morphological variation, distribution, and genetic analyses. Genetic differentiation between regions was significant, with F ST values ranging from 0.07 to 0.137. Immigration rates estimated using a Bayesian method and population ancestry analyses suggested no or very limited gene flow among regional types, even in the area of overlap between types. These results strongly support the classification of porpoises in these regions into distinct evolutionarily significant units, including at least two separate species, and therefore they should be treated as different management units in the design and implementation of conservation programmes.

  • snp discovery based on cats and genotyping in the finless porpoise Neophocaena phocaenoides
    Conservation Genetics, 2009
    Co-Authors: Shuzhen Li, Heyi Ji, Kaiya Zhou, Guang Yang
    Abstract:

    Single nucleotide polymorphisms (SNPs) discovery and genotyping were performed for the finless porpoises (Neophocaena phocaenoides). About 202 comparative anchor tagged sequence primers derived from genomes of human, mouse and some other mammals were used to screen the finless porpoise population. Of the 51 SNPs discovered, 25 were further characterized with ideal genotyping primers and using fragment length discrepant allele specific PCR assay. This is the first report of SNP loci for the finless porpoise, which is helpful to provide some novel molecular markers and new genetic information relevant to the conservation and management of this endangered species.

  • sequence variability at three mhc loci of finless porpoises Neophocaena phocaenoides
    Immunogenetics, 2007
    Co-Authors: Shixia Xu, Kaiya Zhou, Guang Yang
    Abstract:

    Major histocompatibility complex (MHC) class II DQB and DRA genes and class I gene of finless porpoises (Neophocaena phocaenoides) were investigated by single-strand conformation polymorphism and sequence analysis. The DRA, DQB, and MHC-I loci each contained 5, 14, and 34 unique sequences, respectively, and considerable sequence variation was found at the MHC-I and DQB loci. Gene duplication was manifested as three to five distinct sequences at each of the DQB and MHC-I loci from some individuals, and these sequences at each of the two loci separately clustered into four groups (cluster A, B, C, and D) based on the phylogenetic trees. Phylogenetic reconstruction revealed a trans-species pattern of evolution. Relatively high rates of non-synonymous (d N) vs synonymous (d S) substitution in the peptide-binding region (PBR) suggested balancing selection for maintaining polymorphisms at the MHC-I and DQB loci. In contrast, one single locus with little sequence variation was detected in the DRA gene, and no non-synonymous substitutions in the PBR indicated no balancing selection on this gene.

Wang Ding - One of the best experts on this subject based on the ideXlab platform.

  • Genetic diversity in the yangtze finless porpoise by RAPD analysis
    High technology letters, 2020
    Co-Authors: He Shunping, Wang Ding, Chen Daoquan, Zhao Qingzhong, Gong Weiming
    Abstract:

    To estimate the genetic diversity in the Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis), the randomly amplified polymorphic DNA technique was applied to examine ten animals captured from the Yangtze River. Out of 20 arbitrary primers used in the experiment, seventeen produced clearly reproducible bands. Calculated by Nei's formula d = 1-N A B /NT, the genetic distances ranged from 0.0986 to 0.5634. Compared with other cetacean populations, this genetic distance is quite low. Such a low genetic diversity suggests that this population may be suffering from reduced genetic variation, and be very fragile. More studies are needed for understanding the basis for this apparent low genetic diversity and to help protect this endangered, unique population.

  • a pilot study on isolation of microsatellite dna in the yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis
    2008
    Co-Authors: Zheng Jinsong, Liao Xiaolin, Tong Jingou, Wang Ding
    Abstract:

    To the aim of developing specific microsatellite markers for the endangered Yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis 72 microsatellite DNA sequences were isolated using an improved FIASCO (Fast Isolation by AFLP of Sequences Containing Repeats) protocol. According to Weber's classification rules, these sequences were divided into three categories: perfect repeat sequences (58.3% of total), imperfect repeat sequences (22.2%), and compound repeat sequences (19.5%). Thirty PCR printer pairs were designed and synthesized, and then screened by a sample panel of 12 random selected Yangtze finless porpoises. As a result, 14 of them were proved to be polymorphic exhibiting 2 to 13 alleles (mean 5.86 alleles/locus). Their average observed heterozygosity and expected heterozygosity were 0.560 and 0.709 respectively. These are the first batch of specific microsatellite markers for the Yangtze finless porpoise, and they should play great role in succedent conservation genetics studies.

  • determination of serum amino acid concentration in free ranging and captive yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis
    2008
    Co-Authors: Lin Gang, Hao Yujiang, Wang Ding
    Abstract:

    Using high performance liquid chromatographic method, for the first time, this study determined the concentrations of 17 serum amino acids of the Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) in Tian-e-zhou Baiji Nature Reserve and the Baiji Dolphinarium of Institute of Hydrobiology, Chinese Academy of Sciences. The results showed that the mean concentrations of 14 serum amino acids (Aspartic acid Asp, Glutamic acid Glu, Serine Ser, Arginine Arg, Glycine Gly, Threonine Thr, Alanine Ala, Isoleucine Ile, Leucine Leu, Phenylalanine Phe, Valine Val, Lysine Lys, Tyrosine Tyr and Cysteine Cys) of captive porpoises were significantly higher (p < 0.0001 or 0.05) than those of free-ranging animals, except for Proline Pro, Methionine Met and Histidine His. No significant differences of serum amino acid concentrations were noted between genders and between mature and immature free ranging Yangtze finless porpoises. Glu of captive Yangtze finless porpoise was the highest, then was the Asp and Lys within the 17 serum amino acids. Glu of free-ranging Yangtze finless porpoise was the highest too, then was the Lys and Asp. Met was the lowest in both captive and free-ranging Yangtze finless porpoise. The ratio between essential amino acid (EAA) and nonessential amino acids (NEAA) was 0.83 and 0.92 in free-ranging and captive Yangtze finless porpoises, respectively. There was significant difference between the ratios (p < 0.01).

  • genome size determination of yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis
    Acta Zoologica Sinica, 2006
    Co-Authors: Du Bo, Wang Ding, Zhang Xianfeng, Guo Zheng, Zhang Jing
    Abstract:

    The present study determined C-values of 23 individuals of Yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis by flow cytometry using chicken erythrocyte DNA content as a standard.The Yangtze finless porpoise’s lymphocyte cells were extracted from whole blood samples stored at three different conditions.For determining the actual C-value of chicken erythrocyte,we firstly standardized its C-value controlled by human C-value of 3.50 pg/C,and then the chicken C-value of 2.35 pg/2C was used in the following determinations.Result shows that the C-value of the Yangtze finless porpoise is 3.27 pg with the genome size of 3.17×109 bp.The C-values for male and female are 3.29 pg and 3.25 pg,respectively.The C-values of Yangtze finless porpoises reared in captivity and wild are 3.06 pg and 3.30 pg,respectively.Analyzed by Independent-Samples T Test,it’s found that the C-values of different genders have no significant difference,whereas,the C-values of wild Yangtze finless porpoises and that reared in captivity have significant differences,the C-value of Yangtze finless porpoise in captivity is smaller than that of the wild ones.It’s assumed that the stability of environmental factors has certain influences on animal genome size variation.

  • review on breeding biology of yangtze finless porpoise Neophocaena phocaenoides asiaeotientalis
    Acta Theriologica Sinica, 2006
    Co-Authors: Hao Yujiang, Wang Ding, Zhang Xianfeng
    Abstract:

    There a re three Neophocaena phocaenoides subspecies recognized in Chinese waters: South China Sea population, N. p. pho caenoides; Yellow Sea population, N. p. sunameri; and Ya ngtze population, N. p. asiaeorientalis. The Yangtze pop ulation, or Yangtze finless porpoise, is the most endangered subspecies that onl y inhabits in the Yangtze River and its adjacent lake systems. It is a unique freshwater and relatively isolated population of the Neophocaena. The wild population of the Yangtze finless porpoise has decreased drastically in last two decades because it also ine scapably suffers the impacts of the deterioration of the Yangtze environm ent as the Baiji (Lipotes vexillifer) does, such as constructio n of hydropower facilities, overmuch and illegal fishing, busy water traffic, an d heavily water pollution etc. It is no doubt that it is very important to prot ect and rehabilitate the natural Yangtze habitats. However, it seems that there is no chance for improvement of the Yangtze environment in the foreseeable future. Therefore, it is a practical measure to protect the animal from extinc tion by ex-situ conservation in a long run. Captive bree ding is seen as one of essential practices of the ex-situ conservation for this animal. Obviously, the necessary knowledge on breeding b iology plays a key role for successful captive breeding. To better understand t h e data on reproductive biology of the Yangtze finless porpoise, the previous wor ks on the reproduction of the animal in recent 30 years are reviewed. And the p r esent research status is expounded in terms of ecology, physiology, ethology, an atomy and histology. Some contradictions and controversial conclusions in previous studies are discussed in this paper. Furthermore, some important issu e s and urgent research points are also discussed to try to shed a light in furthe r studies on breeding biology, and it is also hoped to provide a base for breedi ng program of this animal in captivity.

Kunio Shirakihara - One of the best experts on this subject based on the ideXlab platform.

  • food habits of finless porpoises Neophocaena phocaenoides in western kyushu japan
    Journal of Mammalogy, 2008
    Co-Authors: Miki Shirakihara, Akira Takemura, Kenji Seki, Kunio Shirakihara, Hideyoshi Yoshida, Takeshi Yamazaki
    Abstract:

    We examined the stomach contents of 87 finless porpoises (Neophocaena phocaenoides) in the Ariake Sound‐ Tachibana Bay area and Omura Bay in western Kyushu, Japan, between 1987 and 1992. Fish (Gobiidae and Atherinidae) were the most numerous and most frequently occurring prey in Omura Bay, whereas both cephalopods (Octopodidae, Sepiidae, Sepiolidae/Sepiidae, and Loliginidae) and fishes (Clupeidae, Engraulidae, and Sciaenidae) were equally important in Ariake Sound‐Tachibana Bay. Species compositions in the commercial catch differed between the 2 waters, suggesting that differences in prey availability may explain the geographical variation in diet. Finless porpoises in Ariake Sound‐Tachibana Bay showed ontogenetic and seasonal variations in diet. The mean length at weaning was estimated to be 101 cm, corresponding to approximately 6 months of age. Calves fed on small-sized demersal fish and cephalopods. The predominant prey species for sexually mature individuals (including lactating females) consisted of konoshiro gizzard shad (Konosirus punctatus) and cephalopods. Seasonal availability of these organisms may be related to births in the fall‐winter season in Ariake Sound‐Tachibana Bay. Size-dependent prey selectivity was equivocal. Day‐night difference in foraging time was not indicated by the index of stomach fullness.

  • Finless porpoise abundance in Omura Bay, japan : Estimation from aerial sighting surveys
    Journal of Wildlife Management, 1998
    Co-Authors: Hideyoshi Yoshida, Kunio Shirakihara, Miki Shirakihara, Hirohisa Kishino, Akira Takemura
    Abstract:

    We used aerial surveys and line-transect methods to estimate the abundance of the finless porpoise (Neophocaena phocaenoides) in Omura Bay, Japan. We conducted 4 surveys once each season from August 1993 to May 1994. We surveyed 621.5 km and sighted 54 porpoise groups (87 animals). In the spring survey, we detected porpoises offshore as well as inshore, whereas porpoises were mostly inshore in all other seasons. The abundance of porpoises was estimated to be 187 animals (0.6 individuals/km 2 , CV = 20%).

  • A population size estimate of the finless porpoise,Neophocaena phocaenoides, from aerial sighting surveys in Ariake Sound and Tachibana Bay, Japan
    Researches on Population Ecology, 1997
    Co-Authors: Hideyoshi Yoshida, Kunio Shirakihara, Hirohisa Kishino, Miki Shirakihara
    Abstract:

    We estimated the population size of the finless porpoise ( Neophocaena phocaenoides ) in Ariake Sound and Tachibana Bay of western Kyushu, southwestern Japan, from aerial sighting surveys using line transect methods. All 12 surveys were conducted from May 1993 to May 1994 (8 in Ariake Sound and 4 in Tachibana Bay). In addition to these, 14 surveys were also carried out to obtain information on porpoise occurrence in Tachibana Bay (5 surveys) and in neighboring Sumo Nada (5) and Yatsushiro Sound (4). In Ariake Sound, 225 porpoise groups (369 animals) were detected during all flights totalling 1,694.4 km. In Tachibana Bay, a total of 997.8 km was surveyed and 55 groups (290 animals) were sighted. However, no sightings were recorded in Sumo Nada (distance searched = 148.7 km) and Yatsushiro Sound (208.4 km). In Ariake Sound, few sightings were recorded from waters shallower than 5 m in depth. In Tachibana Bay all animals were detected from waters of less than 50 m depth. The population size was estimated as 1,983 animals in Ariake Sound (95% CI = 1,382-2,847), 1,110 in Tachibana Bay (95% CI = 642-1,920), and 3,093 in the 2 waters (1.3 individuals/km^2, 95% CI = 2,278-4,201).

  • age growth and reproduction of the finless porpoise Neophocaena phocaenoides in the coastal waters of western kyushu japan
    Marine Mammal Science, 1993
    Co-Authors: Miki Shirakihara, Akira Takemura, Kunio Shirakihara
    Abstract:

    Abstract: In the coastal waters of western Kyushu, Japan, a total of 97 incidentally taken or stranded finless porpoises, Neophocaena phocaenoides, was collected for studying age, growth and reproduction. An additional 17 specimens from the Inland Sea were used for a comparison of life history. Mean neonatal body length was 78.2 cm. Both males and females grew to around 140 cm by 5 yr of age. The maximum body lengths of males and females in western Kyushu were 174.5 cm and 165.0 cm, respectively, which were smaller than those recorded in other Japanese waters. Females probably attain sexual maturity at ages of 6–9 yr and at body lengths of 135–145 cm. Males probably mature sexually at ages of 4–6 yr, at body lengths of 135–140 cm and at weight of testis of 40–150 g. The lack of females aged 5–6 yr and males aged 4–5 yr precluded firm conclusions on ages at sexual maturity. Parturition in western Kyushu was estimated to be prolonged from autumn to spring, whereas in the Inland Sea and Pacific waters it was restricted from spring to summer with a peak in April. These geographical differences and available information on distribution implies that the finless porpoises in western Kyushu constitute a local population.