2008  Vol. 4  No. 3

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Research Paper
Abstract:

Selective breeding were performed on the base populations of Oreochromis mossambicus and O.hornorum respectively, and F4 generations were produced and evaluated. Compared with control group, the daily growth rate of F4 of O.mossambicus and O.hornorum was improved by 27.96% and 36.73% (P < 0.05), and the average selection response per generation was 6.99% and 9.18%, while variation coefficient of body weight was reduced by 24.83% and 36.33% over the control group, respectively. At the first sex maturity, the mean body weight of the selected group F4 was increased more than two times of the control group respectively, and their hybrids[O.mossambicus ♀ (XX) × O.hornorum ♂ (ZZ)]had high and stable male rate. All these results showed that selection response of the two kinds of tilapia is remarkable, and the individual growth rate was turned to be consistent in the selected population. It also indicated that there are still some selection potentials in F4 generations, and it is feasible to proceed with selective breeding for growth of the two kinds of tilapia.

Abstract:

The statistical experimental design (Plackett-Burman and Box-Behnken design) was applied to optimize the culture medium of nitrite oxidizing bacteria for improving the nitrite oxidizing rate. Estimated optimum medium composition of the nitrite oxidizing rate was as follows: NaHCO3 2.0 g · L-1; NaNO2 2.36 g · L-1; Na2CO3 0.37 g · L-1; NaCl 0.34 g ·L-1; KH2PO4 0.05 g · L-1; MgSO4 · 7H2O 0.05 g · L-1; and FeSO4 · 7H2O 0.03 g · L-1. The nitrite oxidizing rate reached a maximum at 905.0 mg NO2-N · (g MLSS · d)-1(mixed liquor suspended solids, MLSS).In the field trial, 50 L of nitrite oxidizing bacteria concentrate (1.99 g VSS · L-1)(volatile solid, VSS) with 850 mg NO2-N · (g MLSS · d)-1 were added to 0.6 hectares of the aquaculture water. Nitrite level in all treated ponds remained very low compared to the steady increase observed in all of the control ponds during 7 days.

Abstract:

Effects of Bacillus licheniformis De on grass carp (Ctenopharyngodon idellus) culture were analyzed with indexes including fish survival rate, pH, water transparency, dissolve oxygen, ammonia nitrogen and nitrite nitrogen. The results showed that the survival rate, pH and water dissolve oxygen of test groups increased 3.2%, 3.9%, 25.5%, respectively, but water transparency, ammonia nitrogen and nitrite nitrogen decreased 38.5%, 74.6%, 69.3%. In conclusion, the productive efficiency, assessment indexes and environmental quality in test groups all optimized in a certain extent.

Abstract:

Under the water temperature and pH ranges of 28.2~29.7℃ and 7.6~8.3, respectively, study on the suitable and optimal salinities respectively for survival and growth of Babylonia areolata was investigated using experimental ecological methods, aiming at providing scientific evidence for its aquaculture. The salinity at which juvenile mortality of 50% in 120 hours occurred in experiment was defined as the critical survival salinity, and the salinities in between the highest and lowest were regarded as the suitable survival salinities. The salinity responsible for 30% of the highest growth rate was defined as the critical growth-suitable salinity, and salinities in between the highest and lowest were regarded as the growth suitable salinity. Salinities at which the highest survival or growth rates among groups were not significantly different by multiple comparison were set to be the optimal survival or growth salinities. Results showed that the suitable survival salinity for B.areolata juveniles was 19.18~41.39, the optimal survival salinity was 26.0~34.4. The growth suitable salinity was 19.28~39.96, the growth optimal salinity was 26.0~31.6. When salinity was beyond the optimum, the juveniles were more sensitive to low salinity.

Abstract:

The population hybridization was conducted by using clams of two shell color strains " ocean red" (R), " zebra" (Z) strains in October of 2007. The experiments was consisted of RR (R♀×R♂), ZZ (Z♀×Z♂), RZ(R♀×Z♂), ZR (Z♀×R♂) groups. The results showed that difference of shell length, weight and fecundity of parents were significant between two shell color strains (P < 0.05). There were no difference on egg-diameter, fertilized rate and size of D larvae among each experimental groups (P > 0.05).The hatching rates in hybrid groups were higher than in control groups (P < 0.05).At the planktonic stage, survival heterosis was obvious instead of growth heterosis for larvae tested. Survival heterosis were(10.30±1.92)%and(16.30±1.04)%, respectively for RZ and ZR, and growth heterosis for RZ, ZR were(1.63±0.81)%and(2.58±0.67)%.Growth rates for RZ, ZR were (8.64±0.32) and (8.67±0.31) μm · d-1, respectively (P < 0.05).At indoor rearing stage, obvious growth and survival heterosis were found. The growth heterosis of RZ, ZR were(11.25±2.98)%and(20.31±2.10)%, the growth rates were (9.88±1.45) and (10.79±1.32) μm · d-1, and the survival heterosis were(40.85±9.90)%and(57.08±11.98)%, respectively. There was no significant difference of survival heterosis between RR and ZZ (P < 0.05).

Abstract:

The main immune indexes of hybrid tilapia (Tilapia nilotica ♀×T.aurea ♂) were measured every two weeks. The 0.05 and 0.10 mg · L-1 sodium dodecyl benzene sulfonic (SDBS) had not affected the numbers of NBT-positive cells and content of IgM. The 0.40 mg · L-1 SDBS significantly reduced the numbers of NBT-positive cells and content of IgM in eighth week. The 0.70 mg · L-1 SDBS significantly reduced the numbers of NBT-positive cells and content of IgM in sixth week. The 0.10 mg · L-1 SDBS significantly reduced the numbers of NBT-positive cells and content of IgM in fourth week. Mortality of hybrid tilapia after injection of Aeromonas hydrophila (0.40, 0.70 and 1.00 mg · L-1 SDBS) was higher than the control. These results indicated that low concentration of SDBS (0.05 and 0.10 mg · L-1) did not affect the immune function of hybrid tilapia, but the higher concentrations of SDBS (0.40, 0.70 and 1.00 mg · L-1) will apparently reduce the immune function of hybrid tilapia along with time changed.

Abstract:

Five isozymes (EST, ME, AST, LDH and MDH) from six tissues (muscle, heart, liver, kidney, brain and spleen) of Trachinotus ovatus were preliminarily studied using vertical polyacrylamide gradient gel electrophoresis. The results showed that the tissue specificity of these isozymes is very obvious. The expression of enzyme gene loci and the activity of isozyme varied with different tissues. The number of EST isozyme bands was 3, which was encoded by 2 gene loci. Est-1 expressed in all 6 tissues, and Est-2 only existed in liver and kidney. The number of LDH isozyme bands was 3, which was encoded by 3 gene loci. Ldh-2 only expressed in kidney. Two divisions of MDH were found from T.ovatus. It was encoded by 2 loci, and the most specific MDH was in liver. The isozyme bands of MDH3 also existed in all 6 tissues. The number of ME isozyme band was 1, which was encoded by 1 loci. AST isozyme which was encoded by two loci was only found in liver and kidney.

Abstract:

The complete sequences of cytochrome b (Cyt b)genes in Pseudosciaena crocea and Scioenops ocellatus, and the partial sequence of cytochrome b (Cyt b) gene in Miichthys miiuy were amplified using PCR technology. The PCR products were sequenced directly. 1 140 bp fragments of Cyt b genes in P.crocea and S.ocellatus, and 1 125 bp fragment of Cyt b gene in M.miiuy were obtained. Comparing obtained sequences, the comparability similarity of three sequences was 91.49%. Information of the base composition and the mutation sites were obtained. The difference of three sequences was obvious. The results contributed not only genetic data to economic utilization of three species but also scientific basis to analysis of genetic diversity in China Sea. Moreover, molecular phylogenetic tree of the Cyt b DNA sequences in the three species was reconstructed with the NJ method based on the inherited distance and the result showed that the inherited distance between the M.miiuy and the S.ocellatus was small.

Abstract:

The phytoplankton species composition, quantity distribution, diversity, community structure and its relationship with the environmental factors in Shacheng Harbour sea area in the northern Fujian Province were analyzed based on the survey in April, 2006. One hundred and fifteen species were identified, among which coastal eurythermic species were predominant, showing obvious characteristics of subtropical population fauna. The results showed that the average abundance of phytoplankton in Shacheng Harbour was 3 113.24 ind · L-1. The abundance was higher in the inner bay than that in the outer bay in horizontal distribution. The surface abundance was a little higher, but there was no significant gradient in different water layers in vertical distribution. Shannon-Wiener diversity index, Margalef richness index, Pielou evenness index and Simpson dominance index were 2.390, 2.650, 0.726 and 0.306, respectively. Phytoplankton community structure was analyzed by PRIMER software. It showed that the community structure was divided into two groups of inner bay group and outer bay group, with the former being higher heterogeneity. The major environmental factors were DO, pH, NO3 and SiO4. The phytoplankton community structure and environmental factors was significantly correlated (P=0.1%) with correlation coefficient of 0.372. The subset of environmenal variables (pH, NH4, SiO4) matched phytoplankton community structure best, with correlation coefficient of 0.701.

Abstract:

Sargassum horneri is one of the main components in the subtidal seaweed flora along the Chinese warmer water coast. With the changes of global climate and the increases of human activities, the once abundant algal biomass of S.horneri along the coast of Nanji Island (27°27′N, 121°05′E) has been reduced in recent years. In order to understand this changes, in situ observation of field individual plants were performed during 2006~2007 at four field sites distributed at intertidal zones. It was found that, (1) field population was mainly composed of the annual sporophytes derived from zygote via sexual reproduction, while the biannual plant was only about 5% of the total population; (2) the optimal temperature for growth and reproduction was 11~16℃. Sexual reproduction peaked at the temperatures of 16~20℃. Sporophytes of S.horneri are tolerant of a wide spectrum of irradiance, and are thus one of the ideal candidates in reconstruction of artificial seaweed beds.

Review
Abstract:

In this paper, researches on artificial reef design were previewed in terms of hydrodynamics, biology and materials science. The interaction of hydrodynamics and design of artificial reef was discussed as well. Researches on materials science, hydrodynamics force, biological factors and reef deployment were summarized, in order to provide an excellent artificial reef model for construction of artificial reefs (ARs) in South China Sea area.

Abstract:

Satellite remote sensing and geographic information system (GIS) technology provide a new method for the research of marine fishery resources, and have been used widely. This article summarized the application of remote sensing on fishery environment factors, such as sea surface temperature, chlorophyll concentration and applications of GIS, integrated RS and GIS technologies in marine fisheries were reviewed briefly as well. On the base of these, matters needed to pay attention to the application of RS and GIS technology in marine fisheries were also discussed.

Abstract:

Groupers are one of important aquaculture species. Due to lack of natural seedling, the technique of artificial breeding is critical and important. This paper reviewed the advances in research on artificial breeding technique, reproductive biology, early stage of development, larval rearing in groupers as well as current problems faced. The prospect for the future study was also presented.