淞江鲈在中国地理分布的历史变迁及其原因

淞江鲈（Trachidermus fasciatus Heckel）隶属于鲉形目杜父鱼科淞江鲈鱼属,是中国四大淡水名鱼之一。该物种属暖温性底层小型肉食性降海洄游鱼类,曾在中国东南沿海地区较为常见,但近几十年来在许多地区却难以找到其踪迹。为查明其分布区的历史变化,1999年开始,通过查询文献资料和标本馆藏,结合实地考察,比较分析了有记载以来中国境内淞江鲈种群地理分布的历史变迁。结果显示,历史上,淞江鲈广泛分布于环太平洋的渤海、黄海、东海沿岸及与之相通的河流中。文献资料记载的分布区涵盖辽宁、河北、山东、江苏、浙江、福建、台湾7省和天津、上海2市;馆藏标本记录的仅涵盖辽宁、河北、山东、江苏、浙江5省和天津、上海2市;实地调查的现有种群分布区已退缩为辽宁、山东、浙江3省。造成淞江鲈种群分布区减小的原因主要在于人类干扰导致环境污染、洄游通道受阻、产卵场破坏等,致使其生存生境质量显著下降,甚至丧失,以至于其无法完成整个生命周期。基于目前的状况,建议进一步加强对该物种的拯救工作,进一步完善保护措施,使得该物种免遭灭绝之厄运。     

Distribution and diet of the roughskin sculpin, <Emphasis Type="Italic">Trachidermus fasciatus</Emphasis>, larvae and juveniles in the Chikugo River estuary,Ariake Bay,Japan

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.     

A new species of sculpin,Icelus ecornis (Scorpaeniformes: Cottidae) from the southwestern Okhotsk Sea

A new cottid species,Icelus ecornis, is described on the basis of 31 specimens collected from 159–226 m in the southwestern Okhotsk Sea off Hokkaido, Japan. It is distinguished from all other members of the genusIcelus by the following combination of characters: no supraocular and parietal spines; short blunt nuchal spine; cirri absent from head and body, except for supraocular, parietal and nuchal regions; platelike scales of dorsal row bearing 6–10 long uniform spinules; tubular lateral line scales bearing small spines on dorsal and posterior margins; large oval black spot on first dorsal fin; 16–20 anal fin rays.     

Molecular cloning and characterization of a C-type lectin in roughskin sculpin (Trachidermus fasciatus)

C-type lectins, as the members of pattern-recognition receptors (PRRs), play significant roles in innate immunity responses through binding to the pathogen-associated molecular patterns (PAMPs) presented on surfaces of microorganisms. In our study, a C-type lectin gene (TfCTL1) was cloned from the roughskin sculpin using expression sequence tag (EST) and rapid amplification of cDNA ends (RACE) techniques. The full-length of TfCTL1 was 696 bp, consisting of a 95 bp 5′ untranslated region (UTR), a 498 bp open reading frame (ORF) encoding a 165 amino acid protein, and a 103 bp 3′ UTR with a polyadenylation signal sequence AATAAA and a poly(A) tail. The deduced amino acid sequence of TfCTL1 contained a signal peptide and a single carbohydrate recognition domain (CRD) which had four conserved disulfide-bonded cysteine residues (Cys⁶¹-Cys¹⁵⁸, Cys¹³⁴-Cys¹⁵⁰) and a Ca²⁺/carbohydrate-binding site (QPD motif). Results from the qRT-PCR indicated that TfCTL1 mRNA was predominately expressed in the liver. The temporal expression of TfCTL1 was obviously up-regulated in the skin, blood, spleen and heart in time dependent manners by lipopolysaccharide (LPS) challenge, whereas in the liver, TfCTL1 was initially down-regulated from 2 h to 48 h followed by an abrupt up-regulation at 72 h. Recombinant TfCTL1 CRD purified from Escherichia coli BL21 was able to agglutinate some Gram-positive bacteria, Gram-negative bacteria and a yeast in a Ca²⁺-dependent manner. Further analysis showed that TfCTL1 can bind to several kinds of microorganisms selectively in a Ca²⁺-independent manner. These results suggested that TfCTL1 might be involved in the innate response as a PRR.     

Growth and morphological development of larval and juvenileepinephelus bruneus (perciformes: Serranidae)

The growth and morphological development of larval and juvenileEpinephelus bruneus were examined in a hatchery-reared series. Average body length (BL) of newly-hatched larvae was 1.99 mm, the larvae growing to an average of 3.96 mm by day 10, 6.97 mm by day 20, 12.8 mm by day 30, 22.1 mm by day 40 and 24.7 mm by day 45 after hatching. Newly-hatched larvae had many mucous cells in the entire body epidermis. By about 4 mm BL, the larvae had developed pigment patterns peculiar to epinepheline fishes, including melanophores on the dorsal part of the gut, on the tips of the second dorsal and pelvic fin spines, and in a cluster on the ventral surface of the tail. Spinelets on the second dorsal and pelvic fin spines, the preopercular angle spine and the supraocular spine, had started to develop by about 6 mm BL. The notochord tip was in the process of flexion in larvae of 6–8 mm BL, by which time major spines, pigments and jaw teeth had started to appear. Fin ray counts had attained the adult complement at 10 mm BL. After larvae reached 17 mm BL, elements of juvenile coloration in the form of more or less densely-pigmented patches started to appear on the body. Squamation started at 20 mm BL. Major head spines had disappeared or became relatively smaller and lost their serrations by 20–25 mm BL.     

The molecular cloning and characteristics of a fibrinogen-related protein (TfFREP1) gene from roughskin sculpin (Trachidermus fasciatus)

Fibrinogen-related proteins are a family of glycoproteins containing fibrinogen-like domains. Many members of these proteins play important roles in innate immune responses. We isolated a fibrinogen-related protein gene (TfFREP1) from roughskin sculpin (Trachidermus fasciatus). The TfFREP1 encoded a protein of 264 amino acids, including 231 amino acids with fibrinogen-like domains. Both quantitative real-time polymerase chain reaction and western blot analysis showed that TfFREP1 was mainly expressed in skin and gill tissues of T. fasciatus. The expression level of TfFREP1 was upregulated at both mRNA and protein levels after stimulation of lipopolysaccharide. These results suggest that TfFREP1 may be involved in T.?fasciatus immune reaction.     

Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta,heteroptera)

Summary 1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.2. Dark and light gland cells can be differentiated on account of the degree of electron density. The former predominate during the last larval stage and in the young imago, the latter in mature males and females. It is highly probable that the light cells are the active (i.e. hormone producing) ones and the dark cells the inactive ones.3. The active cells are characterized by rough endoplasmatic reticulum (often in whorls), small amounts of smooth endoplasmatic reticulum and many multivesicular bodies. Abundant free ribosomes, a not particularly well developed Golgi apparatus, dense bodies, and cytolysomes are present in active and inactive cells.4. The nuclei contain one to four prominent and variously shaped nucleoli, which show differences between adult males and females with respect to their location in the nucleus.5. The corpus allatum cells of Oncopeltus are obviously engaged in extensive protein synthesis. Tangible structural indications for the manufacture of juvenile hormone were not observed. Possible sites of hormone release are discussed.This study was made possible by a fellowship and grants from the Deutsche Forschungsgemeinschaft and was supported by research grants, administered by Prof. Scharrer, from the U.S.P.H. Service (NB-05219; NB-00840 and NS-07512). Present address of author: Institut für Allgemeine Zoologie der Johannes Gutenberg-Universität, D-6500 Mainz, Saarstraße 21, Bundesrepublik Deutschland.I am indebted to Prof. Scharrer for guidance and criticism. I also wish to express my appreciation to Mrs. S. Wurzelmann and Mr. S. Brown for their excellent technical assistance.     

A new sculpin, <Emphasis Type="Italic">Microcottus matuaensis</Emphasis>, from the central Kuril Archipelago (Scorpaeniformes: Cottidae)

A new cottid species, Microcottus matuaensis, is described on the basis of 16 specimens (27.9–81.3mm SL) collected from tide pools of Matua Island, central Kuril Archipelago. This species is the second species of the genus Microcottus, and is distinguished from M. sellaris in having three pairs of distinct bony tubercles on the dorsal surface of occiput, a deeply concave interorbital space, and absence of the first pore of the supraorbital sensory canal.     

Morphobiological features of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner) (Scorpaeniformes, Cottidae) from Sakhalin

Data on the flathead sculpin Megalocottus platycephalus taeniopterus from different regions of Sakhalin are provided. Based on analysis of the morphological material, the estimates of taxonomically significant characters of the northern and southern subspecies are clarified. They include the relative length of the lower jaw, the extent of development of postorbital and occipital tubers, the coloration of pectoral fins, the shape of free ends of ventral fin rays, and their relative length and coloration in females. The habitats of M. platycephalus taeniopterus are considerably attributed to the desalinated sites of coastal waters. In the areas of eastern Sakhalin, its individuals stay in brackish water lakes and lagoons for a considerable part of their life; some individuals migrate to coastal waters for feeding in summer. Considerable differences are observed between populations in the life span, rate of growth, and the age of maturation of individuals. In the regions of eastern and western Sakhalin, the pattern of feeding of M. platycephalus taeniopterus differs considerably: in eastern regions, it is a clearly pronounced predator, and in western regions, it feeds mainly on invertebrates.     

Ultrastructure of differentiating hemocytes in the embryo of Oncopeltus fasciatus Dallas (Insecta,Heteroptera)

Summary The hemocytes of Oncopeltus differentiate rather early during embryogenesis. They are segregated by the mesoderm soon after its formation (about 50h after egg deposition). Newly segregated hemocytes show the typical features of embryonic cells: many free ribosomes, a few strands of rough ER, the cisternae of which are considerably distended, electron lucent vacuoles around the periphery, and glycogen deposits. A few hours thereafter the hemocytes undergo striking subcellular changes. First, glycogen, electron lucent vacuoles and rough ER disappear and phagocytotic activity can be observed. Golgi complexes become well expressed and give rise to electron dense vesicles which fuse to larger bodies. Then, rough ER develops again and occupies large areas of the cytoplasm. Its cisternae are often considerably distended by proteinaceous secretions. All hemocytes undergo the same steps of differentiation.Embryonic hemocytes obviously play a decisive role in the elimination of waste products, in particular of tissue debris that results from programmed cellular death. The significance of the conspicuous protein secretions is not fully understood. They may participate in the deposition of the acellular connective tissue, or may have some of the other functions ascribed to insect blood cells.Larvae and imagines of Oncopeltus have four types of hemocytes, which agree rather well with those found in Rhodnius (Lai-Fook, 1970). All embryonic hemocytes, aside from the newly segregated ones, represent plasmatocytes but, unlike plasmatocytes of postembryonic stages, they contain no large inclusion bodies. Newly segregated embryonic hemocytes, in addition to their typical embryonic features, have some similarities with larval and adult prohemocytes. Oenocytoids and granulocytophagous cells are absent in the embryo. Some aspects concerning the differentiation and classification of hemocytes are discussed.Supported by research grant Do 163 from the Deutsche ForschungsgemeinschaftThe author is grateful to Ms. K. Schmidtke and Ms. M. Ullmann for technical assistance     

Isolation and characterization of polymorphic microsatellite DNA markers in the rock bream (Oplegnathus fasciatus)

From a (GT)₁₃-enriched genomic library of Oplegnathus fasciatus, 14 polymorphic microsatellite were isolated and characterized in a test population with alleles ranging from two to nine, the observed and expected heterozygosities from 0.0000 to 1.0000, and from 0.1726 to 0.8507, respectively. Five loci deviated from the Hardy–Weinberg equilibrium, and linkage disequilibrium between two loci was significant. Two loci were also polymorphic in Pagrosomus major assessed for cross-species amplification. These polymorphic microsatellites will be useful for genetic diversity analysis and molecule-assisted breeding for O. fasciatus. Changwei Shao contributed equally.     

Cadmium effects on development and reproduction of Oncopeltus fasciatus (Heteroptera: Lygaeidae)

Newly hatched nymphs of the insect Oncopeltus fasciatus were exposed to various concentrations of CdCl2 administered in drinking water until the end of adult life. Significant nymphal mortalities were observed at concentrations above 30 mg Cd/l (corresponding to the LC50). The duration of the nymphal stages increased in proportion to the Cd concentration; at the lowest Cd concentration of 10 mg Cd/l, the median duration was significantly prolonged by one day, while at the highest concentration of 100 mg Cd/l it was increased by 10 days over the control group. The weight of newly emerged adults lineally decreased with Cd concentration, being reduced to half the weight of controls at 100 mg Cd/l. In addition, a proportionality between delay in development and weight reduction was found in Cd-treated adults. Survival of adult females was decreased at concentrations higher than 10 mg Cd/l, while males were only affected at 30 mg Cd/l or higher doses. Reproduction was the most affected parameter. Oviposition rate, fecundity and fertility of females exposed to 10 mg Cd/l were significantly lower than controls (73%, 58% and 55% relative to controls, respectively). Hatchability of the eggs laid by treated females was also reduced. These results show that development and reproduction of O. fasciatus are seriously impaired at sublethal Cd concentrations.     

Development of eggs, larvae and juveniles of laboratory-reared blue whiting,Sillago parvisquamis (Percoidei: Sillaginidae)

The embryonic, larval and juvenile development of blue whiting,Sillago parvisquamis Gill, are described from a series of laboratory-reared specimens. Mean egg diameter and mean total length (TL) of newly-hatched larvae were 0.71 mm and 1.58 mm, respectively. The eggs were non-adhesive, buoyant and spherical with an oil globule (mean diameter 0.18 mm). Hatching occurred about 20 hours after fertilization at a temperature of 24.0–25.0°C, newly-hatched larvae having 38–40 myomeres. The yolk and oil globule were completely absorbed 3 days after hatching at 2.8–3.2 (mean 3.0) mm TL. Notochord flexion was completed by 7.2–8.2 (7.7) mm TL, and pectoral and caudal fin rays fully developed by approximately 10 mm and 8.5 mm TL, respectively. Completion of fin development occurred in the following sequence: caudal, pectoral, anal and second dorsal, first dorsal and pelvic, the last-mentioned by approximately 11 mm TL. The larvae ofS. parvisquamis andS. japonica, which closely resemble each other in general morphology and pigmentation, could be distinguished as follows. Newly-hatchedS. parvisquamis larvae had more myomeres thanS. japonica (38–40 vs. 32–34) and more melanophores on the dorsal surface of the body (19–28 vs. about 40).Sillago japonica had a vertical band of melanophores on the caudal peduncle, which was lacking in postflexionS. parvisquamis larvae. In addition, juveniles ofS. parvisquamis (larger than 23 mm TL) had melanophores on the body extending anteriorly to below the lateral line to form a midlateral band, whereas no obvious band occurred on similarly-sizedS. japonica juveniles.     

Juvenile development of a flathead,Suggrundus meerdervoortii (Scorpaeniformes: Platycephalidae)

Juvenile development ofSuggrundus meerdervoortii was described, based on twelve specimens (12.9–43.8 mm SL) collected from off Yamagata Prefecture, Japan Sea. Two exterior openings in the lateral line scales were completed at ca. 35 mm SL, with the interopercular flap and iris lappet being visible at ca. 44 mm SL, these all being useful taxonomic characters. In juveniles and additional young and adult specimens (ca. 70–191 mm SL), the proportions of head length, snout length, orbital diameter, caudal peduncle depth and caudal fin length decreased with growth; interorbital width decreased rapidly until ca. 70 mm SL, but more or less stabilised thereafter (70–191 mm SL).     

Facultatively internal fertilization and anomalous embryonic development of a non-copulatory sculpin Hemilepidotus gilberti Jordan and Starks (Scorpaeniformes: Cottidae)

Fertilized residual eggs were observed in the ovaries of spent females of a non-copulatory sculpin Hemilepidotus gilberti Jordan and Starks. Fertilized eggs were present in 23 of 35 females, and approximately 38% of the total residual eggs (n=227) were fertilized. These eggs were thought to be fertilized facultatively with spermatozoa that entered the ovary through ovarian fluid during spawning. The high calcium concentration (1.42+/-0.21 mM kg(-1)) in ovarian fluid, which is beyond the threshold concentration required for fertilization, may allow internal fertilization to occur. Embryos at various developmental stages were observed, but all were deformed and surrounded by unhardened chorions. Since no larvae were observed, all the fertilized residual eggs would have degenerated in the ovary in accordance with other unfertilized residual eggs. These observations suggest that the ovary of the oviparous fish H. gilberti is an unsuitable environment for embryos to develop, possibly because it may be unable to supply developing embryos with needed elements, such as oxygen.     

Male mating success and female mate choice in the river sculpin,Cottus nozawae (Cottidae)

Synopsis Mating success of males and its correlates were investigated in a natural population of the polygynous fluvial sculpinCottus nozawae. Furthermore, the female mate preference of this species was examined experimentally under alternative conditions for mating in a stream. The mating success of individual males (the number of females with which a male mated) ranged between 0 and 8 with a mean of 2.41 in 1983 and 2.52 in 1989, in a population of which the sex ratio was about 1 : 2 in both years, skewed toward females. Mainly due to the excess of nests without egg masses and the few nests with one egg mass, the distribution of male mating success did not fit a Poisson distribution, indicating its non-randomness. Male mating success was not correlated either with the size of the nest rocks or with the male size, suggesting that these two variables are not determinants of mating success. The mate choice experiments demonstrated that females of this species more frequently chose smaller males as mates whose nests already contained eggs than large males without eggs. Additionally, an analysis of stomach contents of guarding males suggested that the parental males ate their own eggs during egg guarding (filial-cannibalism). Based on these results and on a comparison of reproductive characteristics with congeneric species, it is suggested that one of the most important determinants for female mate choice inCottus species may be whether or not parental males are filial egg cannibals.     

Comparative analysis of the karyotype of the sculpin Myoxocephalus ochotensis (Pisces: Cottidae) from the Odyan Bay of the Sea of Okhotsk

The karyotype of the endemic Okhotsk Sea sculpin Myoxocephalus ochotensis Schmidt (Cottidae) from Odyan Bay was studied. The number and morphology of chromosomes were determined, 2n = 42 (2 metacentric, 20 subtelocentric, and 20 acrocentric chromosomes), NF = 44. Variability of chromosome number was not revealed; no difference between male and female karyotypes was found. The karyotype of the Okhotsk sculpin M. ochotensis was compared with karyotypes of the Far East Steller’s M. stelleri (Tilesius), snow M. brandti (Steindachner), and plain M. jaok (Cuvier) sculpins, and to the European shorthorn sculpin M. scorpius (Linnaeus) from White Sea. Their similarities and distinctions were shown.     

松江鲈鱼皮肤的显微和亚显微结构

采用光学显微镜、扫描电镜和透射电镜,对松江鲈鱼(Trachidermus fasciatus)成体皮肤的显微和亚显微结构进行了观察。结果表明,松江鲈鱼体表不同部位皮肤的厚薄不一,但基本结构相似。皮肤由表皮和真皮层构成。松江鲈鱼的皮肤裸露无鳞,表皮层较薄,由约4～8层细胞构成,主要由复层上皮细胞和黏液细胞及基底细胞组成。表层细胞呈扁平、多边形,细胞之间主要靠桥粒紧密连接,连接处形成增厚的边缘嵴状突起。表皮细胞游离面向内凹陷,表面形成指纹状微嵴。黏液细胞呈圆形或卵圆形,散布在上皮细胞之间。黏液细胞内的黏原颗粒具有椭圆颗粒状、均匀致密的块状和疏松丝状3种不同形态。真皮通过基膜与表皮相连,由稀疏层和致密层构成。真皮结缔组织在腹部较厚而在其他部位较薄。表皮与真皮连接处有色素层,头部、背部、尾柄和体侧皮肤色素细胞分布多,色素层明显,而腹部和颏部皮肤缺少色素。松江鲈鱼黄河群体真皮层中有角质棘状突起,而滦河群体则无。头部、体侧和尾柄处皮肤上还分布有侧线孔和表面神经丘等感觉器官。