Abstract:A comparative study of ultrastructural changes of cells and organellae was conducted on diploid and triploid abalones, Haliotis discus hannai, during their spermatogenesis. The results showed that spermatogenesis in diploid abalone co uld be divided into five stages: spermatogonium, primary spermato cyte, secondary spermatocyte, spermatid and spermatozoon. A series of changes o ccurred in morphology and structure, including chromatin condensation, development and fusion of mito chondria, acrosome formation and cytoplasmic diminution. Compared with diploid abalones, the size of the cells and nucleus in the triploid abalone was significantly increased in all levels of spermatogenic cells. Similar spermato gonia structure was found between triploid and diploid abalones. Except for lysosomes, the number of mitochondria, endoplasmic reticulum and other organellae in the primary and secondary spermatocytes was decreased in triploid abalone. No significant difference was found in the size of mitochondria between diploid and triploid spermatocytes. However, the latter did not have a typical shape and lacked developed cristae. The spermato genesis of triploid abalone was retarded at the spermatide stage. Various abnormal formations and collapsed cells w ere observed, and no sperm was detected.

Abstract:3 population2specific RAPD bands , namely S37 277 bp , S11 2660 bp from“Pujiang No. 1”blunt snout bream and S28 946 bp from control , were identified from the amplified bands of 100 10bp2oligo2nucleotide random primers. After gel extraction , cloning and sequencing of the 3 population2specific RAPD bands , three primers (20 base for each forward and reverse primer) were designed according to their sequence information. Then PCR amplification was carried out in the“Pujiang No. 1”and control populations. The results showed that 4 SCAR , namely Sc21 (248 bp) , Sc22 (540 bp , 460 bp) and Sc23 (320 bp) bands , were amplified by the 3 pairs of primers. Among them , Sc22 (540 bp , 460 bp) and Sc23 (320 bp) could be positively amplified in the“Pujiang No. 1”and control populations as well , but SCAR marker (Sc21 , 248 bp) developed from S37 277 bp was“Pujiang No. 1”population specificity. Large samples examination (90 individuals of “Pujiang No. 1”population , 56 individuals of control from Yuni Lake ) showed that the frequency of Sc21 marker in“Pujiang No. 1”blunt snout bream reached 91. 1 % (82/ 90) , but only 14. 3 % (8/ 56) in wild population from Yuni Lake. The high frequency of Sc21 marker in“Pujiang No. 1”blunt snout bream could be used as a specific molecular marker for population identification. And it also indicated that the frequency of some alleles related with economically important trait was increased in“Pujiang No. 1”blunt snout bream , through long2term (16 years) and high selective intensity (0. 03 % -0. 04 % selective rate) mass selection.

Abstract:RT- PCR and RACE( rapid amplification cDNA ends ) were used for the isolation of the full length cDNA of DMO gene from ovary of Oreochromis aurea. Sequence analysis revealed a 1571 bp cDNA containing the 148 bp 5.- untranslated region, 193 bp 3.- untranslated region and 1230 bp open reading frame encoding 409 amino acid. Sequence analy sis revealed the identity rate of deduced amino acid of DMO in O. aurea and O. niloticus is 96. 3%, which showed high homology in species. However, we compared the alignment of deduced amino acid sequences between DMO cDNA from O. aurea and DMRT1 cDNA from O. niloticus , fugu, rainbow tro ut, medaka, rat and human. The score was 25. 7%, 25. 8%, 24. 3%, 29. 7%, 22. 5% and 22. 0%, respectively. These results indicated that DMO and DMRT1 gene may be different genes.

Abstract:DNA polymorphism of thirty individuals of each of the three migrating reproductive populations of Gymnocypris przewalskii (Kessler) in the Qinghai Lake was analyzed by random amplified polymorphic DNA (RAPD) , which were Heimahe population (HM) , Buhahe population (BH) and Shaliuhe population (SL) . A total of 85 loci , including 68 polymorphic ones , were detected from the three populations by using 13 primers. The average percentage of polymorphic loci to total DNA of the three populations was 80. 0 %. The results of data analysis showed that the populations had on average the Nei’s value of 0. 3395 for gene diversity and the Shannon’s information index of 0. 4861 , there existing a relatively abundant genetic diversity. The average genetic distance among the three populations was 0. 0788. The gene differentiation coefficient ( Gst) of 0. 1070 indicated that there was genetic differentiation of a certain degree among the three populations. Clustering analysis by UPGMA method showed that HM and BH were clustered with priority, indicating that the gene flow of both populations was more frequent than that between either and SL.

Abstract:This paper deals with the sequence analysis of mitochondrial 12S rRNA gene fragment and phylogenetic relationship of three mud crabs , Scylla serrata (Forsk l) , S . oceanica (Dana) and S. tranquebarica (Fabricius) collected from Japan , Thailand and . Madagascar. The result indicated that there was length variation among three mud crabs , which was 422bp , 426 bp and 425 bp respectively. Genetic distance inter2species was greater than that intra2species. Trees constructed by distance method and maximum parsimony method using Charybdis japonica and Thalamita prymna as the outgroup indicated that there were three distinct clades corresponding to S . serrata , S . oceanica and S . tranquebarica respectively. It suggested that the three mud crabs should be recognized as valid species and managed as different fishery management unit.

Abstract:The primers for Pelodiscus sinensis and Pelodiscus axenaria were designed by using the sequences of mitochondrial DNA 12S rRNA region of Dogania subplana , Chrysemys picta and Chelonia mydas , 562 base pairs of mitochondrial DNA were amplified and sequenced. Theresultsshowthatthelengthoftheirsequenceisthesame,theA,T,G,Ccontentsaresimilar,thenumberofA,T,G, Cis 209 (37.2%) ,121 (21.5%) ,145 (25.8%) ,87 (15.5%)in Pelodiscus sinensis and 207 (36.8%),120 (21.4%),145 (25.8%), 90 (16 %)in Pelodiscus axenaria. Based on their sequence data , we found there are 13 different nucleotide sites (percentage divergence is 2. 31 %) between Pelodiscus sinensis and Pelodiscus axenaria by using the software of ClustalW , whereas the average number of different nucleotide sites is 3 (percentage divergence is 0. 53 %) in Pelodiscus sinensis and 2 (percentage divergence is 0. 36 %) in Pelodiscus axenaria. The nucleotide percentage divergence is obvious between species , so it suggests Pelodiscus axenaria is a new species in Trionyx. Restriction endonuclease analysis based on sequence data of this DNA fragment revealed the presence of polymorphic sites for MspI endonuclease , there is one site for MspI endonuclease in Pelodiscus axenaria , but none in Pelodiscus sinensis. The restriction profiles obtained by agarose gel electrophoresis when amplicons were cut with MspI enzyme allowed the unequivocal identification of Pelodiscus sinensis and Pelodiscus axenaria.

Abstract:As a high polymorphic and codominant molecular marker, microsatellites, or simple sequence repeats ( SSRs) have been used widely in genetic researches such as genetic maps construction and population polymorphism research. In Porphyra, no effort was devoted to the utilization of microsatellite marker. The biggest obstacle of microsatellite marker is the availability of interested microsatellite loci. One of the mo st convenient methods for obtaining microsatellite loci is to search the public database. In former work, online BLAST software was used to isolate all the d-i nucleotide and tr-i nucleotide microsatellite loci from the Genbank dbEST of Porphyra yez oensis . Total of 211 non-redundant microsatellite loci, amounted to 1. 01% of the dbEST, were exploited from 20 979 EST sequences. Among these microsatellite sequences, 35 dinucleotide micorsatellite repeats which core- unit repeats not less than 7 and 176 trinucleotide micro satellite which repeat numbers no less than 5 were isolated. Then some loci were selected out to design primer s at the flanking regions according to the followed criteria: primer length within 20 ? 2 bp, GC content between 50% and 75%, melting temperature between 50 e and 65e , expected product size between 100 and 300bp and without a secondary structure. 15 microsatellite primer pairs were synthesized and inter- species amplified on 8 filament lines of Porphyra haitanensis , the primer pair s which produced distinct amplified bands were selected out. In this research, total 32 bands were amplified by 5 microsatellite primer pairs in 8 filament lines of P . haitanensis . Among them, 5 bands ( AU192094- 127, AU187410- 335, AU187410- 190, AU194267 - 203, AU194267- 328 note: the former was the name of primer, latter was the molecular weight of selected bands) were cho sen to construct the DNA fingerprinting of 8 filament lines. For the rest two primer pairs of AV435669 and AV432452, multiple band pattern and false positive ( microsatellite repeats were absent from the amplification bands) problems might exist in the inter- species amplification, so the amplified bands of these two primer pairs were excluded from the fingerprint construction. In the constructed DNA fingerprint, each filament line has its unique fingerprint pattern and can be easily distinguished from each other . According to this fingerprint, researchers can trace the genetic background of descendant blades which germinated from 8 filament lines. Besides, the molecular fingerprint can overcome the disability of morphological identification, which was susceptive to the environment affection. In addition, the co- dominant of microsatellite marker made it possible to study the Mendel segregation so as to identify the pure line filaments of Porphyra haitanensis . The fingerprint can also be used to confirm the stage of meiosis during the life history of P. haitanensis, for this purpose, the microsatellite primer should not have the problems of multiple bands and false positive problems, and the microsatellite locus of this primer is heterozygosis. In summary, this paper just built a molecular basis for the future genetic research of Porphyr a haitanensis.

Abstract:The phylogenetic relationships of 5 species of snappers ( Lutjanus stellatus , L . sebae, L. vitta, L . f ulvus and L . fulvif lamma) were studied comparatively, which were based on 2 methods: restriction fragment length polymorphism of mitchondrial DNA ( mtDNA-RFLP) , RFLP of cytochrome b ( Cyt b ) gene segment ( > 900bp) amplified by polymerase chain reaction( PCR-RFLP) . The sample numbers of Lutjanus stellatus , L . sebae, L . vitta, L . fulvus and L . fulviflamma were 17, 17, 35, 17 and 17, respectively, which are collected in the South China Sea from Sep. 2002 to Jun. 2003. The mtDNA being isolated and purified from fresh liver s of samples range from 17. 05? 0. 46 to 17. 77? 0. 91 kb. Having been digested by 19 restriction endonucleases recognized 6 base pair s ( EcoR. , Hind ? , Bgl . , Bgl ? , Sty . , Xba . , Dra . , Pst . , Pvu ? , Xho . , BamH . , Sca . , EcoR . , Sma . , Mlu . , Sal . , Hinf . , Kpn . , Hp a . ) , the mtDNA were analysed. The result of mtDNA-RFLP show s that L . vitta could be divided into HE and HD, based on the co lor of stripe on the middle of the side. The physical maps of mtDNA from L. stllatus and L . sebae have been constructed based on the endonucleases that are chosen from 19 restriction endonucleases. By comparison of the sequence of cyto chrome b gene PCR-RFLP using different amplification templates ( one from purified mtDNA and the other from nDNA) , the possible interferences of nuclear mitochondrial pseudogenes ( Numts) were excluded and the possible pseudogenes from nDNA were preliminarily discussed. Having been digested by 6 restriction endonucleases recognized 4 base pairs( Sty . , Hinf . , Hpa ? , Msp . , Sau96. , Sin . , Taq . , Hae ? ) , the sequences were analy sed. The results of mtDNA PCR-RFLP support that L . vitta could be divided into two species: HE and HD by the 0. 0751 of divergency index. The results reveal that all of the 2 analysis methods are useful for seeking o ut the genetic markers among species effectively. And the results from RFLP indicate that the L . vitta could be divided into two species based on the color of stripe on the middle of the side. At the same time, the constructions of phylo genic trees by neighbor- joining( NJ) method show that there are some differences along different methods on the specific level when they are used for phy logenesis.

Abstract:The changes of triiodothyronine ( T3 ) and thyroxine ( T4 ) levels in serum , eggs and larvae were measured by radioimmunoassay (RIA) after T4 injection in female Japanese eel spawners at doses of 5 , 10 , 15 and 20 mg ?(500g) 1 body weight fish. As results , T3 level reached up to peak value following T4 level up to peak value in maternal serum after 24 h of exogenous T4 injection. Apparently , there was conversion of T4 into T3 in the broodstocks which suggests the presence of the enzyme , 5’ monodeiodinase , in Japanese eel. Meanwhile , along with the T3 and T4 levels in serum up to peak value , the T3 and T4 level in eggs also reached up to peak value. It further indicated that T3 and T4 in maternal circulation could be transferred into the oocytes and subsequently into the larvae. After readjusting the times and doses of T4 injection , it was discovered that the most suitable doses of exogenous T4 injection should be 10 -15 mg?(500 g) 1 body weight and the optimal opportunity of T4 injection should be 12 h before spawning under the condition of 21 ℃ water temperature. Compared with the control , the rate of larval survival in each stage of development tended to show remarkable increase ( P < 0. 01) after spawners were treated with T4. The rate of 92day2old larval survivalwaselevatedfrom1.3%ofcontrolgroupto22.0%oftreatedgroup. However,thelarvaecouldnotsurviveultimately. It suggests that thyroid hormone may not be the only factor of affecting the larvae survival.

Abstract:By artificial fertilization , some mutual2cross experiments were conducted among transparent color crucian carp , red crucian carp , ornamental carp and red purse carp to detect the survival rates , growth speeds and body color separations of hybrids. The results indicated that the four kinds of carps can be crossed each other , and produce fries , with which the lowest hatching rate of self2crosses for ornamental carps is 46. 4 % , whereas 70 % -80 % for other combinations. After artificial feeding for 28 days , there were remarkable differences among hybrids in which the hybrids of transparent color crucian carp and red purse carp and ornamental carp by direct and reciprocal crosses had the slower growth and the lower survival rate than others. There were three body shapes of hybrids which were common carp body and intermediate body. The scale refractive tissues (rainbow cell or guanophore ) were divided into two types which were complete presence and absence. Interestingly , it was more complex and diverse in color separations. The hybrids produced by crosses between transparent color crucian carp and red crucian carp were transparent color. However , the hybrids were gray color when red crucian carp crossed with ornamental carp and red purse carp ; while there were two kinds of colors in hybrids when transparent color crucian carp crossed with the same two carps as red crucian carp.

Abstract:Studies on marine bivalves have demonstrated that suspension-feeding bivalves scan influence the function of ecosystems to a great extent. In dense populations, bivalves can dominate total ecosystem metabolism, nutrient cycling , and grazing of primary producers. Oy ster ( Crassostrea gigas ) is a promising species, which has been widely cultured in the neritic waters in the Bohai Sea and the Yellow Sea. Oyster farming has been bringing not only great economic benefit, but also great burden for the neritic ecosystem due to filtering food and releasing metabolic production. To estimate the effects on neritic eco system of o yster cultivation, the experiments were monthly conducted near Xiao Qingdao Island from March to September 2001. The biodepo sition by Crassostrea gigas and the effects of biodeposition on material flux were measured under natural cultivation conditions. Crassostrea gigas used, with the body sizes of 79. 8- 125. 0 mm shell height and 0. 96- 3. 35 g dry tissue weight, were collected from the oyster farm south of Qingdao . Oyster was div ided into three groups, according to their body size, they were small size ( 80- 95 mm) , middle size ( 95- 110 mm) and big size ( 110- 125 mm) . Each group was arranged for five parallel experiments. The results show that the biodeposition rates was 26. 3- 69. 9 mg.. ind- 1..d- 1, 37. 5- 83. 7 mg.. ind- 1..d- 1 and 44. 1- 103. 7 mg.. ind- 1..d- 1 for small size, middle size and big size of Crassostrea gigas, respectively. The amount of biodepo sit was correlated positively with the shell length and weight, but the per gram body weight biodepo sit negatively. With the water temperature rising form March to September, the chlorophyll a concentration in sea water increased from 1. 6.. 0. 3..g..L- 1 to 7. 3.. 0. 5..g..L- 1 and reached the peak values at 18. 3 .. in June, then went down until September, either the TPM, POM, POC and PON. As a consequence, the biodeposition by each group oyster increased from 26. 3 mg.. ind- 1..d- 1 to 69. 9 mg.. ind- 1..d- 1, 37. 5 mg.. ind- 1..d- 1 to 83. 7 mg.. ind- 1..d- 1 and 44. 1 mg.. ind- 1..d- 1 to 103. 7 mg.. ind- 1..d- 1, then decreased to 49. 0 mg.. ind- 1..d- 1, 76. 9 mg.. ind- 1..d- 1 and 88. 8 mg.. ind- 1..d- 1 in Aug ust or September , respectively . Those demonstrated that water temperature and food concentration were important factors to affect biodeposition of Crassostrea gigas .

Abstract:Peptidoglycan (PG) was isolated from Bifidobacterium thermophilum by TCA extracting , and its weight was 8. 4 % of dry weight of bacterium. The peptidoglycan contained 24. 2 % glycan , 3. 2 % fatty acid and 2. 4 % protein. The concentrations of Gly , Glu, Lys and Ala, the special amino acid of PG, were 157.2, 102.0, 173.8 and 1 061.1μmol?g -1 , respectively. After chemical compositionofPGwasanalyzed,thebiologicalactivitiesofPGwereexaminedtoo. EffectsofPG,whichhadbeendilutedto 0.1% and 1 % by special buffer and broken up by ultrasonic waves , on the activity of Phenoloxidase (PO) , Superoxide Dismutase (SOD) , Alkaline phosphatase (ALP) , Acid phosphatease (ACP) and Lysozyme (LSZ) of the serum of penaeid shrimp , Penaeus japonicus were studied. The results showed that the activity of PO and LSZ had been markedly enhanced and it could maintain in 96 h , the activity of SOD had been enhanced properly and it would decline back in 72 h , after ip PG. The effects of PG on the activity of ACP and ALP were similar , the enzyme activity was mildly increased in 96h. Except Penaeus japonicus , Paralichthys olivaceus were used as experiment animal too. PG could enhance the activity of SOD of fish serum significantly , but this activity was obviously different as time extending and it fell to the original value after 72 h passed. And different concentrations of PG had different effects. The results indicate that PG can be used as immunostimulant in order to enhance the non2specific immune activity of aquatic shrimps and fishes.

Abstract:Three strains of pathogenic bacteria, namely EcGS020802 , EcGS021001 and EcGS020801 were isolated from diseased orange spotted grouper ( Epinephelus coioides) . By physiological and biochemical analyzing , they belonged to Vibrio. In order to further classify them , 16S rRNA and heat shock protein ( HSP60) genes partial sequences were determined. Phylogenetic analysis based on 16S rRNA gene sequences indicated that three strains of pathogeny showed high levels of similarity to Vibrio harveyi , V. alginolyticus and V. parahaemolyticus. The identities among them , above 98. 6 % , were very high. Sequences analysis of HSP60 genes showed that they were very similar to V. harveyi (AF230934) , V. alginolyticus (AF230931) and V. parahaemolyticus (AF230951) , and their nucleotide identities were 95. 7 % , 99. 8 % and 99. 8 % , respectively. Moreover , the similarities with other Vibrio species were all less than 90. 6 %. The nucleotide similarities of HSP60 genes among three isolates were less than 91. 0 %. Phylogenetic tree of Vibrio based on HSP60 genes showed that strains EcGS020802 ,EcGS021001 and EcGS020801 clustered together with V. harveyi , V. alginolyticus and V. parahaemolyticus , respectively. Based on the results obtained, the strains EcGS020802 , EcGS021001 and EcGS020801 were identified as V. harveyi , V. alginolyticus and V. parahaemolyticus , respectively. Results showed that HSP60 gene was fitter to classify marine Vibrios than 16S rRNA gene.

Abstract:In order to characterize the property of metabolic substances of salt2resistant Rhodospirillaceae bacteria , the aseptic metabolic substances were purified by column chromatography on CM -Sephadex C -50. Three protein peaks : PSB2 -1’, PSB2 -2’, PSB2 -3’were obtained. The protein peak of PSB2 -1’had inhibiting activity against the pathogens. The antibacterial protein peak of PSB2-1’was confirmed as electrophoresis purity with SDS -PAGE. Only one band was shown when antibacterial protein was checked by capillary zone electrophoresis. And the molecular weight of antibacterial protein was 9290 Da checked by mass spectrometry. The antagonistic products produced by salt2resistant Rhodospirillaceae bacteria were heat2stable and were not sensitive to ultraviolet radiation , but sensitive to acidity and alkalinity. And the inhibitory activity was influenced by treatment with trypsin , pepsin and subtilisin. The antagonistic substances produced by salt2resistant Rhodospirillaceae bacteria could be preliminarily classified with small heat2stable peptide (SHSP) .

Abstract:Based on historic in2situ ocean primary production data and other environment data from the southern Yellow Sea and East China Sea and consideration of the processes of phytoplankton photosynthesis , a ocean primary production model was developed through the nonlinear least square method. The fitted model was a function of the sea surface chlorophyll , sea surface irradiance , sea surface temperature and transparency. Since the mean chlorophyll concentration was closely related to surface chlorophyll concentration ( R = 0. 91 with data from 242 stations) within the euphotic layer , but neither the total chlorophyll concentration , nor the depth of the euphotic layer did , we introduced another parameter , the transparency which could be derived from SeaWiFS’s data to obtain the euphotic depth. The ocean primary production data could be derived from satellite2based data by our developed model without requiring other data as input. Comparing the model derived daily depth2integrated primary production to the measured one showed a very good result. The monthly distribution of ocean primary production in China Sea was computed using the developed model with chlorophyll , transparency and irradiance data derived from SeaWiFS from January to December in 2000 and the corresponding temperature data from NOAA214. The results showed that there were clear seasonal changes for the primary production in Bohai Sea , Yellow Sea and East China Sea. The primary production reached its highest in May and lowest in February in East China Sea , while it was high in August and low in February in Bohai Sea and Yellow Sea. Since we did not have the synchronous data to evaluate the accuracy of the derivation , this model needs to be examined and modified in the future with more available data.

Abstract:Based on the data of four seasonal investigations in the East China Sea (23?30′-33?N , 118?30′-128?E) from 1997 to 2000 , the distribution and the seasonal changes of Euphausiids abundance and the relation between its abundance dynamics and fish ground were discussed in this paper through qualitative and quantitative methods. Results showed that the total abundance of Euphausiids peaked in autumn , and declined to the lowest in winter. The abundance in spring was the second highest in four seasons. Since Euphausia nana in winter , spring , summer and Pseudeuphausia sinica in autumn contributed more to the total abundance , they actually dominated the variations of the total abundance. Moreover , it was found that the total abundance in summer showed linear correlation with bottom water temperature and 10m salinity , while the abundance in other three seasons did not show significant correlation with hydrographic factors. High abundance area of Euphausiids was located in the converging area of Taiwan warm current and other water masses in autumn , suggesting that the variation of the total abundance was dependent on water masses and the dominant species. The latter was also related to their ecological features. It was also found that the high abundance area nearly overlapped the grazing areas of some economic fishes such as Trichiurus lepturus , Scomber japonicus and Larimichthys polyactis.

Abstract:Kaozhouyang Bay is a typical semi2closed bay extended to the inland from Honghai Bay in South China Sea , which covers 29.7 km2 of total water area and 13. 73 km2 of beach area with the unique natural environment and predominant resource condition inside the bay. Being ranked to be the ecological mariculturing demonstration area in Guangdong Province , the bay was abundant in some special culturing species such as the famous“Tiechong Hao”(one species of oyster) . However , due to the lacking of planning program and scientific management , the phenomenon of disorderly development and over2utilization with the fishery multiculture in the waters of the bay in the recent years resulted in the frequent occurrences of fish diseases and then , to some extent , hampered the continual development of the fishery multiculture in Kaozhou Bay. In order to protect the ecological environment inside the bay , a survey on the ecological environment was carried out from 1999 to 2000. This paper reported the characteristics of the species composition and quantity distribution of phytoplankton in the bay. According to the result , altogether 188 species were identified in the survey waters , which belonged to 5 phyla with 142 species of Bacillariophyta , 22 species of Pyrrophyta , 5 species of Cyanophyta , 18 species of Chlorophyta and 1 species of Euglenophyta. Of all the phyla, diatom was the main predominant group. The species composition mainly consisted of the coastal species of fresh and salty2fresh , and the horizontal distribution and seasonal variation accorded with the water salinity variation in the survey waters. In the dry season , the predominant species changed complicatedly with an obvious regional succession characteristic and great variation , and the main predominant species were Rhizosolenia alata f . gracillima , Chaetoceros lorenzianus and Nitzschia paradoxa. While in the wet season , the predominant species was simple , and most of the waters was dominated by Skeletonema costatum and S . tropicum with the average predominant degree of 95. 8 % , and in the northwestern waters the predominant species changed to Merismopedia glauca and Skeletonema costatum. The seasonal variation and regional variation of the diversity index of phytoplankton were obvious and showed a trend that the dry season was higher than the wet season and the northwestern waters was higher than the southeastern waters. The mean cell density in the wet season reached to 26 471. 7 ?104 ind?m 3 , which was 66. 2 times that of the dry season. The distribution of the cell density showed the increasing trend from the northwestern waters to the southeastern waters.

Abstract:The paper reported on results of the exploratory fishing of Chinese large scale trawlers since April 2000 in the open sea of the southeast Pacific adjacent to exclusive economic zone of Chile and the basic situation of commercial exploitation after 2003, and also discussed the prospects of commercial exploitation. It points out that the meteorology and o ceanic condition are favorable to operate all the year round in the exploratory fishing area; the status of jack mackerel resources is stable for sustainable exploitation. The fishing fleet of China has got profit since 2003, and there is certain potential of increasing production. However, the equipment conditions of Chinese fishing vessels are timeworn and it. s become the bottleneck to enhancing profits. Finally, the paper suggested that for the sustainable development of pelagic fishery of China, the government should pay more attention to the fishery policies on international fishery co operation and international competition.

Abstract:On- the- spot experiments of different kinds of gathering- fish lamps were carried out in the fisheries studies of the Symlectoteuthis oualaniensis fishing ground in the north-west of Indian Ocean in October 2003. According to the dimension of the ship and the products, the illumination distribution of gathering- fish lamp and the fishing efficiency were studied. When the output of metal halide lamps is 240 kW, in the above 5 m water layer the illuminations are more than 100 lx , the iso- illumination curve of 10 lx is in the depth of 20 m, the iso- illuminance curve of 0. 01 lx is in the depth of 55 m. When the output of high pressure sodium lamps is 10 kW, the average illumination on the sea surface is 3 lx, the iso- illuminance curve of 0. 01 lx is in the depth of 20 m. According to the suitable illumination from 0. 01 lx to 10 lx of some squids, the ratio of water volume of high pressure sodium lamps and gathering- fish lamps is 1..5. When using high pressure sodium lamps, the density of squid w ill increase, the fishing layer will be shallower , the fishing efficiency will be higher, and the average product will be 3 times as much as before. It also shows that the total power output of the large squid jigging boat should be 112 to 160 kW in fishing Symlectoteuthis oualaniensis, and the suitable illumination for Symlectoteuthis oualaniensis is about 0. 01 lx .

Abstract:For different recruitmen-t fishing types, the methods for estimate of maximum sustainable yield (MSY or YS ) and maximum sustainable catches ( CS ) using recruitment curve parameters are different. This paper presented and discussed the methods for two recruitment- fishing types. The two types are: Type 1 is one time reproduction in all one. s life and continuous fishing. Type 2 is many times reproduction in all one. s life and seasonal fishing. We combined catches equation with Ricker reproduction model or Beverton- Ho lt reproduction model to produce new equilibrium catches equations:These equations may be used separately to estimate CS , YS , fishing mortality coefficient need for CS ( FcS ) , and fishing mortality coefficient need for YS ( FS ) . We calculated CS , YS , FcS , and FS at same M for type 1 and type 2. The results show that, FS does not equate with FcS . We considered that FS may be less than FcS but FS can not be greater than FcS for same recruitment curve.

Abstract:With the fast development of aquaculture , fish meal needs increased in recent years , however the quantity of fish catching decreases gradually. Fishmeal is a limited feed resource , and serious concern exists on the future availability of this feedstuff for incorporation in fish diets. Undoubtedly , fish meal is well recognized as the best dietary protein source for most marine carnivorous fishes which required high dietary protein levels compared to omnivorous or herbivorous fish. Fishmeal is known for their high content of essential amino acids and fatty acids , low carbohydrates , high digestibility , low levels of anti2nutritional factors (for fresh fish meal) and is a very good source of minerals and is highly palatable. Thus fish meal is in high demand as the protein source for many formulated diets. However , production of fish meal consumes approximately 35 % of the total global fish catch , and the increasing price and potentially unstable supply in the market could be limiting factors for marine fish culture. There have been strong efforts to define and develop cost2effective protein sources that can , at least partly , substitute for expensive high2quality fish meals in least2cost feed formulations. The search for fish meal substitutes and alternative dietary protein sources is an international research priority that could be of considerable economic advantages. Therefore it is urgent task to find animal and plant protein sources in place of fish meal. Among these , plant feedstuffs have received most attention in recent years , but due to their amino acid unbalances , presence of anti2nutritional factors and low palatability , a high level of replacement of fish meal with plant feedstuffs in omnivorous fish is generally not well accepted. This paper reviews the research status for other protein sources replacing fish meal based on available information in the literature. Animal and plant protein sources nutrient values are evaluated from the aspect of digestibility , anti2nutrients , physiological status and suitable supplementation.

Abstract:Fish immunology has achieved great progress in recent years. While before 1990s, most researches focused on the fish systematic immunity, and the mucosal immunity of fish had not been given enough attention. Indeed, it has been shown that fish mucosal immunity plays an important role in disease defense. Fish mucosal immunity research hasmade some exciting progress in this decade. This review will focus on such progress: Constitution of mucosal2associated tissues and distribution of different immune cells, including T/ B lymphocytes, granules, monocytes, macrophages, goblet cells, etc, in these sites have been well described with the development of some monoclonal antibody to these cells and associated techniques. Non2 specific immune response mechanism of mucosal tissues reported these years, such as secretion of non2 specific anti2bacteria and anti2fungi substances inmucus, the respiratory bur st, enzyme activity of immune cells and so on, is believed important for fish disease defense. The specific immunity of mucosal tissues also attracts much interest and makes great achievement in antigen presenting, MHC genes, antibody producing and antibody secreting cells, comparison of serum andmucus immunoglobulin, relationships of immune response between different mucosal immune tissues. Whether mucosal immune system is independent of systematic immune system is another interesting question and causes great concern. In recent years, some evidences from phyletic evolution and ontogenesis show that mucosal immunity is prior to systematic immunity in evolution. Dynamics of antibody producing of mucosal tissues and serum in immersion or oral vaccines immunized fish also shows immune response can be elicited in mucosal tissues independent of systematic immune system. Some researchers also begin to pay attention to factor s involved in mucosal immune regulations, for instance, neuromodulators and cytokines. The level of these factors changes in fish immune response process but the mechanisms of regulation still remain unknown. Prospect of the promising future of fish mucosal immunity has also been discussed in this review.

Abstract:The metaphase chromosome preparation of the fries PHA and colchicine injection. : The tonguefish Cynoglossus semilaevis (G?nther) bottom. metaphase chromosomes of one year old young fish which has physiologically sex differentiation has been got from their renal tissues by the method of The karyotypes were examined. The result shows that there are 42 acrocentric chromosomes in diploid and their karyotype formula is 2n = 42t , and there existed heterotypic sex chromosome which belongs to ZW/ ZZ type. The sex ratio in artificial bred stock is nearly 1∶1.

Abstract:Using conventional histochemical methods and scanning electron micro scope, the egg surface of mature oocyte of Pelteobagrus vachelli was observed. The micropyle is funne-l like and consists of micropylar vestibule and micropylar canal. The opening of micropylar vestibule is about 11. 35 Lm in diameter while entrance of the micropyle to the oocyte is only about 2. 6 Lm. There are plenty of micropores on the surface near the micropyle. Micropyle might act as an apparatus leading spermatozoa to penetrating an oocyte. Regular cord- like structures between basal membrane ( the outermost layer of egg surface) and plasmic membrane ( the inner layer of eg g surface) are found. These cord- like structures, each abo ut 16. 75 to 18. 50 Lm in length, 5 Lm in diameter , comprised small balls whose diameters vary from 2. 18 to 2. 5 Lm and are arranged compactly under the basal membrane. These kinds of structures are zona radiata and act as special eg gshell. After activation of the oocytes, the cord- like structures would partially transform into mucoprotein. To our best knowledge, this paper is the first report on stereo view of the zona radiata of teleost o ocyte.

Abstract:Effects of ionizing irradiation of 60Co-C ray on mortality and growth of one year- old Pacific oysters ( Crassotrea gigas ) were studied. Irradiation was conducted at 4 e and without sea water, and the survival, shell length, shell width, whole wet weight and condition index of irradiated oy sters were measured. A biphasic dose response effect of 60Co-Cirradiation on Pacific oyster with high stimulatory response dose range to 100 Gy, and strong hormesis effects had been observed. Gamma ray induced mortality happened within 90 days after irradiation, and the relation between dosage ( D) and mortality at 90 day s could be described by the equation of M90= 0. 0041D2- 0. 1816D ( R2 = 0. 9958) w ith an LD50/ 90 of 135 Gy, indicating that the Pacific o yster has strong resistance to 60Co-Cirradiation. Growth in shell length, shell width and whole wet weight of Pacific oy ster were also enhanced by 60 Gy of 60Co-C ray. The condition index was also enhanced by 60Co-C irradiation in the do sage range from 40 to 100 Gy, with the maximum stimulatory response of 2. 5 fold of control value at the 40 Gy do sage, suggesting that the accelerating effects of Cray on growth of the Pacific oyster led to increase in dry meat. Results of this study showed that ionizing irradiation might be useful in the improvement of production traits in shellfish.

Abstract:Viral nervous necrosis ( VNN) is a worldwide disease among teleost fish. In the mainland of China, VNN was first identified in 2 species of hatchery-reared groupers, Epinep helus akaara and E . coioides . In the present study , samples were collected from larvae of E . akaar a w ith signs of VNN in Dayawan bay which is located in so uthern China. The complete viral coat protein gene was amplified using extracted total RNA as template. The reverse transcription po lymerase chain reaction ( RT-PCR) amplification was performed using primers containing a heterolo gous restriction site for NotI. PCR products were cloned into pcDNA3 vector and sequenced. The results indicated that the coat protein gene of Dayawan iso late ( RG-CN) was 1056 bases in length and contained a single open reading frame ( ORF) of 1017 bases encoding a protein of 338 amino acids. The sequence similarities between the coat protein gene of RG-CN and other 8 isolates of NNV from Dayawan, Taiwan, Japan, Singapore and France were 79. 1%- 99. 5% at the nucleotide level and 83. 7%- 100% at the amino acid level, respectively. The homo logy between RG-CN and the other 5 isolates from groupers was high and relatively lower between RG-CN and guppy nervous necro sis virus ( GNNV) , sea bass nervous necrosis v ir us ( DIEV) , but more divergences existed between RG-CN and striped jack nevo us necro sis virus ( SJNNV) . Compared w ith SJNNV, RG-CN and the other 7 iso lates all lacked 6 nucleotides and 2 amino acids in the same po sitions. Based on the result of molecular phylogenetic analysis, Dayawan iso late belongs to red- spotted grouper nervous necrosis virus ( RGNNV) genotype.