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1.
截线抽样法用于鄱阳湖江豚种群数量研究初报 总被引:15,自引:0,他引:15
运用截线抽样法调查了在春季 4月间鄱阳湖区长江江豚(Neophocaena phocaenoides asiaeorientalis)的种群密度和数量,得出该地区长江江豚种群密度估计值为 0.1940头/km2,估计数量为 388头。探讨了截线抽样法用于浅水型淡水湖泊调查的可行性和有效性以及要注意的问题。 相似文献
2.
J. S. Zheng X. L. Liao J. G. Tong H. J. Du M. C. Milinkovitch D. Wang 《Conservation Genetics》2008,9(4):1007-1009
The finless porpoise (Neophocaena phocaenoides) is one of the smallest cetacean species widely distributed in the shallow coastal waters of the Indo-Pacific Oceans. The
population size of the Yangtze subspecies (N. p. asiaeorientalis) has sharply decreased in the last two decades and access to objective data on its population structure and genetic diversity
would be of great assistance for their proper management. Here we report on the isolation of nine polymorphic microsatellite
using the “Fast Isolation by AFLP of Sequences Containing repeats” (FIASCO) protocol. Polymorphism was assessed using 30 porpoise individuals randomly sampled in the Yangtze River. The number
of alleles per locus varies from 2 to 9, with an average value of 5.56, whereas the ranges of observed and expected heterozygosities
were 0.300–0.633 (mean 0.496) and 0.473–0.804 (mean 0.659), respectively. 相似文献
3.
Distance software: design and analysis of distance sampling surveys for estimating population size 总被引:2,自引:0,他引:2
Len Thomas Stephen T. Buckland Eric A. Rexstad Jeff L. Laake Samantha Strindberg Sharon L. Hedley Jon R.B. Bishop Tiago A. Marques Kenneth P. Burnham 《Journal of Applied Ecology》2010,47(1):5-14
4.
We studied the diet of larval and juvenile Japanese anchovy Engraulis japonicus in the upper Ariake Bay, Japan. Diet was analyzed by examining the digestive tracts; feeding intensity, proportion of empty
guts, and prey selectivity were calculated. Anchovy density was negatively influenced by temperature and positively by salinity
and prey density. Diet was dominated by Acartia omorii, which was positively selected with two other copepods, Calanus sinicus and Pseudodiaptomus marinus. In contrast, Oithona davisae was highly dominant in the environment but was absent in anchovy guts; thus, this copepod was negatively selected, with two
others, Tortanus derjugini and Sinocalanus sinensis. Overall, larger prey were positively selected and smaller ones were negatively selected; value of electivity index correlated
negatively with prey size. Larvae [<18 mm of standard length (SL)] showed significantly lower feeding intensities and higher
rates of empty guts than juveniles (≥18 mm SL). In juveniles, feeding intensity increased steadily as the fish grew in size,
with a corresponding reduction in empty guts. Feeding intensity correlated positively and empty gut correlated negatively
with fish size. We suggest that larger prey are important diets for postlarval Japanese anchovy in Ariake Bay. 相似文献
5.
Larvae and juveniles of the roughskin sculpin Trachidermus fasciatus were collected during four cruises in March and April 2001 to study the distribution and diet of the fish in the Chikugo
estuary in the northern Ariake Bay, Japan. Sampling was conducted at seven stations covering an area approximately 30 km in
length along the estuary, with salinity ranging from nearly 0 to about 30 PSU. Gut contents were analyzed by separating, identifying,
and counting the prey organisms. Plankton samples were collected during each cruise to study the numerical composition and
abundance of copepods in ambient water. A total of 1790 larvae and juveniles of T. fasciatus were collected; they were distributed in the five uppermost stations, covering approximately 20 km and ranging in salinity
from 0.4 to 27.4 PSU. The fish fed almost exclusively on a single calanoid copepod species, Sinocalanus sinensis, which was numerically the most abundant in the ambient water at the upper part of the Chikugo River. At the lower part of
the river, the fish positively selected S. sinensis while negatively selecting other species. T. fasciatus larvae experienced a high proportion of empty guts and low feeding intensity at around 9.0 mm body length, which appears
to be associated with commencement of exogenous feeding. The proportion of empty guts reduced sharply at subsequent stages
and was accompanied by an increase in feeding intensity. The oligohaline and mesohaline areas are important nursery grounds,
and S. sinensis is an important prey copepod species for the larval and juvenile T. fasciatus in the Chikugo estuary. 相似文献
6.
Manabu Hibino Taro Ohta Takane Isoda Kouji Nakayama Masaru Tanaka 《Ichthyological Research》2007,54(4):367-373
We collected eggs and larvae of the Japanese temperate bass, Lateolabrax japonicus, and present horizontal and temporal changes of distribution relative to development and growth during the species pelagic
life history in Ariake Bay. Sampling was conducted from the inner to central region (11 sampling stations) of Ariake Bay using
a plankton net (80 cm diameter, 0.5-mm mesh) from November 2000 to February 2001. Both eggs and larvae were collected most
abundantly in mid-December. The CPUE of eggs in the surface layer was higher than the middle layer, which is in contrast to
that at the larval stage. Most eggs were collected around the central and western regions of the bay. The distribution of
eggs shifted vertically to the middle layer with development. Yolk-sac larvae were collected in the central region of the
bay, and preflexion and flexion larvae were more abundantly collected in the inner region of the bay. The body length of larvae
around the inner bay was larger than in the central region. The pelagic life history can be summarized as follows: eggs are
distributed around the central region of the bay and eggs and larvae expand their distribution to the inner and shallower
waters with growth. We conclude that the shift of vertical distribution in pelagic stages and the hydrographic features of
the middle layer form one of the mechanisms enabling the inshore migration of L. japonicus. 相似文献
7.
Morphological and genetic characteristics of sea bass,Lateolabrax japonicus, from the Ariake Sea, Japan 总被引:1,自引:1,他引:0
Sea bass,Lateolabrax japonicus, from the Ariake Sea, characterized by black dots on the lateral body region as in the Chinese sea bass,L. sp., were examined and compared morphologically and genetically withL. japonicus andL. sp. Some meristic characters of the Ariake form tended to fall midway between values for the two former species. Genetic
features, evaluated by isozyme analyses, indicated that the Ariake form as represented a simple Mendelian population, there
being no significant differences from a Hardy-Weinberg equilibrium according to chi-square tests. Although some extreme differences
in allelic frequencies were found at some loci betweenL. japonicus andL. sp., the Ariake form possessed many heterozygotes at thePROT-1
* locus, in addition to allelic frequencies at some loci conforming to those ofL. sp. Average allele numbers per locus, rate of polymorphic loci and average heterozygosity of the Ariake form were higher
than for eitherL. japonicus orL. sp., indicating high genetic variation in the former. The results suggested that the Ariake population is genetically independent
of other populations ofL. japonicus, but might be genetically influenced byL. sp. 相似文献
8.
长江江豚对八里江江段的利用及其栖息地现状的初步评价 总被引:11,自引:0,他引:11
通过定点和流动观察的方法,作者使用行为指数和栖息地利用指数定量分析了长江江豚(Neophocaena phocaenoides asiaeorientalis))于1996—2000年间对八里江江段的利用和选择状况。结果表明:江豚在八里江江段的行为指数大小顺序为摄食>抚幼>玩耍>休息,摄食和抚幼是江豚在八里江江段的优势行为;江豚栖息于离岸距离100—300m的近岸带占81.8%,栖息于水深小于9m的水区占73.3%;江豚分布密度随水深增加而逐步递减(典型的指数分布);江豚活动水区的流速范围是0.3-1.2m/s,透明度范围是0.2—0.8m,江豚在八里江江段对水体流速和透明度没有明显的选择性;栖息地利用指数高的断面一般是饵料鱼类聚集、2—4股水流的交汇处。八里江江段的众多异质小生境为江豚提供了充足饵料和繁育抚幼的适宜场所;同时八里江江段为江豚提供了庇护、休息和玩耍的足够活动空间。八里江江段成为长江干流适宜江豚活动的最佳栖息地之一,也是常年江豚在此大规模集聚的理想江段之一[动物学报49(2):163—170,2003]。 相似文献
9.
Gen Kume Keisuke Furumitsu Shinya Tanaka Atsuko Yamaguchi 《Environmental Biology of Fishes》2009,85(4):289-298
Size at sexual maturity, reproductive cycle, and fecundity of the guitarfish, Rhinobatos hynnicephalus, were examined in Ariake Bay, Japan. Females reached sexual maturity at a larger size than males [total length (TL) at 50%
sexual maturity: males, 431 mm; females, 476 mm]. Monthly gonadosomatic indices of males decreased abruptly from July to August.
Histological examinations confirmed the presence of mature spermatozoa in the testes in July, with semen in seminal vesicles
in July and August. Preovulatory ova were observed in females with near-term embryos in August. Parturition occurred in August,
immediately followed by mating, ovulation, and fertilization. Gestation period is approximately 1 year. Fertilized uterine
eggs without embryonic development were present throughout the annual reproductive cycle. Embryonic development began in June
and ended in August, indicating that R. hynnicephalus undergoes embryonic diapause (9 months). Fecundity increased with TL and ranged from 1 to 9 (mean, 4.4) embryos per litter. 相似文献
10.
Gastropods Nucella heyseana were collected from 1999 to 2001 from different habitats in Vostok Bay (Sea of Japan). The spatial distribution, the seasonal and interannual dynamics, and the composition of aggregations of this mollusk were analyzed. In Vostok Bay, N. heyseana inhabits biotopes that are typical of this species and other members of the genus and sometimes forms aggregations with an unusually high density and biomass (up to 1690 spec/m2 and 3680 g/m2), thus exceeding 10–40 times the greatest values reported elsewhere for populations of the southern Kuril Islands and Pos'eta Bay (Sea of Japan). N. heyseana is a typical polyphagous predator, and its diet includes numerous species of the associated fauna of bivalve and gastropod mollusks (more than 30 species). The abundance, composition, and stability of local aggregations of N. heyseana are largely dependent on the abundance dynamics of its prey (primarily the most common species, such as Mytilus trossulus, Ruditapes philippinarum, Protothaca euglypta, and Littorina spp.). The opinion on the low density of N. heyseana in southern Primorye (Golikov, Kussakin, 1978) is probably based on a lack of information about the intertidal fauna of this region compared to the South Kuril Islands. 相似文献
11.
L. V. Zvereva 《Microbiology》2009,78(4):498-501
The taxonomic composition of marine mycelial fungi was determined in the interstitial habitats of the Vostok Bay littoral (Peter the Great Bay, the Sea of Japan). A total of 39 species of ascomycetes and anamorphic fungi were detected and identified. The predominant species of the intertidal zone were Corollospora maritima, C. lacera, Carbosphaerella leptosphaerioides, Arenariomyces trifurcatus (Ascomycota), Alternaria alternata, Scolecobasidium arenarium, and Zalerion maritimum (anamorphic fungi). The complete list of species of obligately marine ascomycetes and anamorphic fungi from the interstitial habitats of the Vostok Bay littoral is presented for the first time 相似文献
12.
Features of the morphology, longevity, and growth of the gastropod mollusk Nucella heyseana collected in different seasons in 2000–2001 in Vostok Bay (Sea of Japan) were investigated. Shell surface features such as grooves and spurs of the axial sculpture have proven to be unhelpful in the estimation of individual age and growth rate of this species. Concentric rings on the outside of the operculum formed yearly in the cold season are useful for these purposes. The longevity of N. heyseana in southern Primorye is 10 years; this value is similar to the life span of mollusks from the southern Kuril Islands. Local differences in longevity, growth allometry, and age changes in the body size and mass of N. heyseana in relation to habitat conditions are discussed. 相似文献
13.
ABSTRACT The long-tailed goral (also called the Amur goral) Naemorhedus caudatus (subfamily Caprinae), a vulnerable and protected species designated by IUCN and CITES, has sharply been declining in the population size and is now becoming critically endangered in South Korea. This species has been conserved as a natural monument by the Korean Cultural Heritage Administration since 1968. In this study, using 78 fecal DNA samples with a non-invasive genetic approach, we assessed the genetic integrity and individual identification-based population size for the goral population from Seoraksan National Park representing the largest wild population in Korea. Using the successfully isolated 38 fecal DNA, phylogeographic and population genetic analyses were performed with mitochondrial DNA control region (CR) sequences and nine microsatellite loci. We found seven CR haplotypes, of which five were unique to the Seoraksan population, considering previously determined haplotypes in Korean populations. The Seoraksan population showed higher haplotype diversity (0.777?±?0.062) and mean number of alleles (4.67?±?1.563) relative to southern populations in Korea reported from previous studies, with no signal of a population bottleneck. Microsatellite-based individual identification estimate based on probability of identity (PID) indicated a population size of ≥30 in this population. Altogether, we suggest that for future management efforts of this species in the Seoraksan National Park, conserving its genetic integrity as an ‘endemic’ lineage, and curbing a decrease in its number through mitigating habitat destruction might be key to secure the population for the long term. 相似文献
14.
白鹤(Leucogeranus Leucogeranus)是国家Ⅰ级重点保护野生动物,唯一一种极度濒危(CR)鹤类,分布和种群数量是评估其濒危程度的重要参数。无人机调查作为目前生态学研究的一个重要调查方法,为查明白鹤的越冬分布、种群数量及幼鸟比例,于2022年1月使用地面监测结合无人机调查的方法在江西、山东、安徽、湖南、湖北等地的湖泊和农田中开展越冬白鹤调查。野外调查共记录白鹤5607只,网络信息检索在调查区域外的8个地点记录白鹤9只,合计记录越冬白鹤5616只。其中江西鄱阳湖记录到越冬白鹤4813只,占总数的85.7%,主要分布在康山垦殖场、五星垦殖场和成新垦殖场;山东黄河三角洲记录到越冬白鹤625只,占总数的11.1%。安徽、湖南、湖北分别记录到越冬白鹤34,63和72只。对部分群体的白鹤幼鸟数量进行统计,4680只白鹤中,记录到幼鸟674只,幼鸟比例为14.4%,其中湖南越冬白鹤幼鸟比例最高,达28.6%,山东越冬白鹤幼鸟比例最低,为11.5%。调查刷新了白鹤种群数量,证实了山东黄河三角洲是目前除江西鄱阳湖外最重要的白鹤越冬地,缓解了白鹤越冬期过度集中的压力。基于本研究结果,我们... 相似文献
15.
A new species of poecilostomatoid copepod, Hemicyclops tanakai n. sp. was collected from burrows of the mud shrimp Upogebia major in an estuarine mud-flat in Tokyo Bay. The new species can be distinguished from its congeners by combination of the following characteristics: setation of the antennule, the segmentation of the antennule, the length–width ratio of the caudal ramus, the ornamentation on the third segment of antenna and the shape of the genital double somite. 相似文献
16.
17.
V. V. Kas'yan 《Russian Journal of Marine Biology》2004,30(2):87-95
The distribution and seasonal dynamics of Centropages abdominalis and C. tenuiremis (Copepoda) in Amursky Bay (Sea of Japan) were studied from May through November 1991. C. abdominalis occurred in plankton from May through August and in November, with a peak density of more than 40000 specimens/m3 in June, at a temperature of 15–18°C. C. tenuiremis occurred from late June through November, with a maximum total density of 6900 specimens/m3 in August, at 23°C. During the observation period, the distribution of species in the bay was irregular due to the hydrological regime and sanitary conditions of water. 相似文献
18.
19.
The seasonal population size of planktonic larvae of mollusks of the soft-shell clam genus Mya were studied in Vostok Bay. The larvae occurred in plankton from the first third of June to early September. The highest density of larvae (279.7 ± 98.7 specimens/m3) was found in late June. In early July, larval numbers decreased sharply, and at the end of the first third of July, only single Mya larvae were found in the plankton. Another increase in larval population was observed in early and late August. The larvae varied in length from 175 to 325 m in June–July and from 150 to 250 m in August. It is likely that the larvae of two species of Mya, M. arenaria and M. uzenensis, are present in the plankton of Vostok Bay. 相似文献
20.
Shigeru M. Shirai Ryoji Kuranaga Hideki Sugiyama Masahito Higuchi 《Ichthyological Research》2006,53(4):357-368
We analyzed patterns of genetic diversity in the sailfin sandfish (Arctoscopus japonicus), focusing on population subdivisions within the Sea of Japan. We observed 270 specimens from nine sampling sites in 1999–2000,
i.e., seven sites in the Sea of Japan and two sites from the Pacific coast of Hokkaido. An additional site (30 specimens)
was sampled from eastern Korea in the spawning season of 2004 for comparison. Forty haplotypes, compiled into three haplogroups
(A–C), were detected based on the comparison of a 400-bp sequence of the anterior part of the mitochondrial control region.
In accordance with previous hypotheses from morphological and molecular analyses, genetic discontinuity between the Sea of
Japan and the Pacific coast of Hokkaido was conspicuous. Within the Sea of Japan, eight sampling sites were not genetically
uniform, and most of the variations among sites were detected between eastern Korea [the “eastern Korea” (EK) population:
distributed from the Korean Peninsula to Mishima, Yamaguchi Prefecture] and the other sites along the coast of Japan [the
“western Japan” (WJ) population: from Oki Islands to western Hokkaido] (Φ
CT
= 0.096, P = 0.0183). The WJ population, having lower genetic variability, showed significant departure from neutrality, indicating
influences through a recent population expansion. The period of the expansion can be estimated to have begun on the order
of 104 years ago. We consider that the present Japan Sea populations have been formed through the invasion of a small ancestral
stock to the Sea of Japan and its population expansion during the last glacial period or later. On the other hand, we failed
to detect distinct evidence of a population expansion in the EK population. Haplogroup C, detected in a high frequency in
this population, was estimated to have mixed with haplogroup A after rapid differentiations of the latter. Therefore, the
EK population, strongly influenced by such a mixture, might possess haplogroup C in a higher frequency and a different haplotype
composition from the WJ population. 相似文献