2018 Vol. 14 No. 2
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Abstract:
Based on the survey data collected from 200 sampling stations by 14 cruises in Daya Bay of the South China Sea in 1988, 2004, 2008 and 2015, we analyzed the characteristics of the secondary productivity and P/B (secondary production/biomass) ratio of macrobenthos for nearly 30 years using Brey's empirical formula. The results show that: 1) Based on ash free dry mass (AFDM), the microbenthic secondary productivity and P/B ratio were 7.44 g·(m2·a)–1 and 0.76 a–1 in 1988, 11.34 g·(m2·a)–1 and 0.86 a–1 in 2004, 4.91 g·(m2·a)–1 and 0.79 a–1 in 2008, 2.93 g·(m2·a)–1 and 0.47 a–1 in 2015, respectively. The secondary productivity and the P/B ratio of macrobenthos increased during 1988−2004, then decreased during 2004−2015. 2) The secondary productivity and the P/B ratio of the main groups of macrobenthos in Daya Bay differed significantly. The variation of secondary productivity and P/B ratio of Mollusca, Polychaeta and Crustacean increased during 1988−2004, then decreased during 2004−2015, being consistent with the trend of the whole macrobenthos in Daya Bay. Different from the other groups, the secondary productivity and P/B ratio of Echinoderm showed a decreasing trend during 1988−2015. 3) Generally, the secondary productivity of the macrobenthos had obvious variation in the northwest of the top Daya Bay and Dapeng’ao Bay. The correlation analysis between macrobenthos community and environmental factors indicates that the secondary productivity was significantly affected by the contents of inorganic nitrogen, phosphorus, dissolved oxygen of seawater and organic carbon content of sediment.
Based on the survey data collected from 200 sampling stations by 14 cruises in Daya Bay of the South China Sea in 1988, 2004, 2008 and 2015, we analyzed the characteristics of the secondary productivity and P/B (secondary production/biomass) ratio of macrobenthos for nearly 30 years using Brey's empirical formula. The results show that: 1) Based on ash free dry mass (AFDM), the microbenthic secondary productivity and P/B ratio were 7.44 g·(m2·a)–1 and 0.76 a–1 in 1988, 11.34 g·(m2·a)–1 and 0.86 a–1 in 2004, 4.91 g·(m2·a)–1 and 0.79 a–1 in 2008, 2.93 g·(m2·a)–1 and 0.47 a–1 in 2015, respectively. The secondary productivity and the P/B ratio of macrobenthos increased during 1988−2004, then decreased during 2004−2015. 2) The secondary productivity and the P/B ratio of the main groups of macrobenthos in Daya Bay differed significantly. The variation of secondary productivity and P/B ratio of Mollusca, Polychaeta and Crustacean increased during 1988−2004, then decreased during 2004−2015, being consistent with the trend of the whole macrobenthos in Daya Bay. Different from the other groups, the secondary productivity and P/B ratio of Echinoderm showed a decreasing trend during 1988−2015. 3) Generally, the secondary productivity of the macrobenthos had obvious variation in the northwest of the top Daya Bay and Dapeng’ao Bay. The correlation analysis between macrobenthos community and environmental factors indicates that the secondary productivity was significantly affected by the contents of inorganic nitrogen, phosphorus, dissolved oxygen of seawater and organic carbon content of sediment.
Abstract:
Based on the bottom trawl survey data for four seasons during 2014−2015, we analyzed the community composition and diversity of fishery resources by studying index of relative importance (IRI), Margalef richness index D, Shannon diversity index H' and Pielou evenness index J', so as to understand the dynamics of community structure. Altogether 574 species had been caught in this region, among which Fish had the largest proportion with over 81%. The IRI result found four dominant species: Acropoma japonicum, Evynnis cardinalis, Trachurus japonicus and Decapterus maruadsi. A.japonicum was the only common dominant species for four seasons and the proportion of traditional commercial fish decreased greatly. For temporal distribution of diversity indices, there was significant seasonal variation for D indiex (highest in autumn but lowest in summer), while no seasonal variation was observed for H' and J'. For spatial distribution, high value of D index was mainly in shallow water with depth less than 40 m, similar for H' and J'. Due to the effect of closed fishing and fishing activities, the diversity indices fluctuated sharply during winter but smallest in autumn.
Based on the bottom trawl survey data for four seasons during 2014−2015, we analyzed the community composition and diversity of fishery resources by studying index of relative importance (IRI), Margalef richness index D, Shannon diversity index H' and Pielou evenness index J', so as to understand the dynamics of community structure. Altogether 574 species had been caught in this region, among which Fish had the largest proportion with over 81%. The IRI result found four dominant species: Acropoma japonicum, Evynnis cardinalis, Trachurus japonicus and Decapterus maruadsi. A.japonicum was the only common dominant species for four seasons and the proportion of traditional commercial fish decreased greatly. For temporal distribution of diversity indices, there was significant seasonal variation for D indiex (highest in autumn but lowest in summer), while no seasonal variation was observed for H' and J'. For spatial distribution, high value of D index was mainly in shallow water with depth less than 40 m, similar for H' and J'. Due to the effect of closed fishing and fishing activities, the diversity indices fluctuated sharply during winter but smallest in autumn.
2018, 14(2): 19-25.
DOI: 10.3969/j.issn.2095-0780.2018.02.003
Abstract:
We investigated and monitored the drifting eggs, larval fish supplementary group in Yujiang Jinling River section during March to September, 2012−2013. The results show that there were 21 species of eggs and larval fish in Jinling River, belonging to 4 orders and 8 families. The dominant species were Heniculter leucisculus (22.2%), Gobiidae (15.0%), Hemibarbus Bleeker (14.4%), Squalidus argentatus (7.2%) and Xenocypris argentea (5.5%). The average amount of eggs per year through the Jinling section was 1.29×108, among which the drifting eggs accounted for 22.3% of the total amount of eggs. We failed to find four major Chinese carps and their eggs. The larval fish had appeared during May to August, whose highest density appeared in June, and the average monthly density of larval fish was 0.041 4 ind·m–3. The density of larval fish and runoff had very significant positive correlation (P<0.01, n=270). The runoff and density of H.leucisculus, Hemibarbus Bleeker and S.argentatus also had significant positive correlation (P<0.05, n=270). Compared with the historical data, the function of Yujiang fish spawning field had changed a lot, and the spawning grounds of four major Chinese carps disappeared basically. Squaliobarbus curriculus, Cirrhinus molitorella, S.argentatus and other fish with small production of drifting eggs could be supplemented successfully, but their amount of resources is small. The annual fluctuation of runoff is an important factor affecting the early resource supplementation in the middle reaches of Yujiang River.
We investigated and monitored the drifting eggs, larval fish supplementary group in Yujiang Jinling River section during March to September, 2012−2013. The results show that there were 21 species of eggs and larval fish in Jinling River, belonging to 4 orders and 8 families. The dominant species were Heniculter leucisculus (22.2%), Gobiidae (15.0%), Hemibarbus Bleeker (14.4%), Squalidus argentatus (7.2%) and Xenocypris argentea (5.5%). The average amount of eggs per year through the Jinling section was 1.29×108, among which the drifting eggs accounted for 22.3% of the total amount of eggs. We failed to find four major Chinese carps and their eggs. The larval fish had appeared during May to August, whose highest density appeared in June, and the average monthly density of larval fish was 0.041 4 ind·m–3. The density of larval fish and runoff had very significant positive correlation (P<0.01, n=270). The runoff and density of H.leucisculus, Hemibarbus Bleeker and S.argentatus also had significant positive correlation (P<0.05, n=270). Compared with the historical data, the function of Yujiang fish spawning field had changed a lot, and the spawning grounds of four major Chinese carps disappeared basically. Squaliobarbus curriculus, Cirrhinus molitorella, S.argentatus and other fish with small production of drifting eggs could be supplemented successfully, but their amount of resources is small. The annual fluctuation of runoff is an important factor affecting the early resource supplementation in the middle reaches of Yujiang River.
Abstract:
Based on the acoustics and bottom trawl survey data of fishery resources in the Nan'ao Island area in autumn 2014 and spring 2015, we analyzed the species composition, dynamic and spatial distribution of fishery resources in that area. The dominant species vaired in different seasons. Priacanthus macracanthus was dominant in autumn and Secutor ruconius was dominant in spring. The average quantity and biomass densities of species assessed by acoustic detection were (26 806±39 968) ind·n mile–2 and (403.68±601.9) kg·n mile–2 in autumn 2014, and (34 416±38 497) ind·n mile–2 and (124.5±139.26) kg·n mile–2 in spring 2015, respectively. Significant difference existed in the quantity and biomass density of fishery resources (P=0.007<0.05; P=0.004<0.05) in single or mixed-fish species captured in autumn 2014. However, the difference in spring 2015 was not significant (P=0.113>0.05; P=0.310>0.05). The difference might be affected by the degree of dominance of the species assessed by acoustics in different seasons. The horizontal distribution of fishery resources was dramatically asymmetrical due to the seasonal schooling behavior of fish species like S.ruconius et.al. Furthermore, variation of TS (target strength) frequency and vertical distribution of single echo detection were obvious in different seasons with the depth of 15 m as the boundary.
Based on the acoustics and bottom trawl survey data of fishery resources in the Nan'ao Island area in autumn 2014 and spring 2015, we analyzed the species composition, dynamic and spatial distribution of fishery resources in that area. The dominant species vaired in different seasons. Priacanthus macracanthus was dominant in autumn and Secutor ruconius was dominant in spring. The average quantity and biomass densities of species assessed by acoustic detection were (26 806±39 968) ind·n mile–2 and (403.68±601.9) kg·n mile–2 in autumn 2014, and (34 416±38 497) ind·n mile–2 and (124.5±139.26) kg·n mile–2 in spring 2015, respectively. Significant difference existed in the quantity and biomass density of fishery resources (P=0.007<0.05; P=0.004<0.05) in single or mixed-fish species captured in autumn 2014. However, the difference in spring 2015 was not significant (P=0.113>0.05; P=0.310>0.05). The difference might be affected by the degree of dominance of the species assessed by acoustics in different seasons. The horizontal distribution of fishery resources was dramatically asymmetrical due to the seasonal schooling behavior of fish species like S.ruconius et.al. Furthermore, variation of TS (target strength) frequency and vertical distribution of single echo detection were obvious in different seasons with the depth of 15 m as the boundary.
Abstract:
The stable carbon isotope of size fractionated zooplankton was studied in the northern South China Sea during summer and winter, 2015. The zooplankton was divided into three groups according to size structure, i.e., micro- (180–380 μm), meso- (380–500 μm) and macro- (>500 μm). Significant spatial difference of zooplankton stable carbon isotope was found. The δ13C value of zooplankton ranged from –24.19 to –19.57 in summer. High δ13C value of micro- and mesozooplankton mainly distributed in south of the survey area. The δ13C value of zooplankton ranged from –23.89 to –19.69 in winter, while the spatial distribution situation was opposite. No obvious seasonal and size fractionated change of δ13C value has been found. The δ13C values of size fractionated zooplankton were positively related to the numerical value of mean chlorophyll a concentration, but showed no significant correlation to zooplankton biomass.
The stable carbon isotope of size fractionated zooplankton was studied in the northern South China Sea during summer and winter, 2015. The zooplankton was divided into three groups according to size structure, i.e., micro- (180–380 μm), meso- (380–500 μm) and macro- (>500 μm). Significant spatial difference of zooplankton stable carbon isotope was found. The δ13C value of zooplankton ranged from –24.19 to –19.57 in summer. High δ13C value of micro- and mesozooplankton mainly distributed in south of the survey area. The δ13C value of zooplankton ranged from –23.89 to –19.69 in winter, while the spatial distribution situation was opposite. No obvious seasonal and size fractionated change of δ13C value has been found. The δ13C values of size fractionated zooplankton were positively related to the numerical value of mean chlorophyll a concentration, but showed no significant correlation to zooplankton biomass.
Abstract:
Zooplankton community characteristics are related to potential fishery resources and effected by environmental factors in coastal reefs. According to four seasonal cruises on fishery ecology in artificial reefs and island reefs of Daya Bay (114.540°E−114.669°E, 22.540°N−22.639°N) in 2015, we analyzed the zooplankton community characteristics and impacts of environmental factors on ichthyoplankton. Altogether 130 zooplankton species were identified. The community structure of zooplankton experienced seasonal variation, including spring group, summer group, autumn group and winter group. The distinct dominant species were Penilia avirostris and Noctiluca scintillens in spring and summer, and Acartia erythraea and Flaccisagitta enflata in autumn and early winter. The annual means of Margalef index, diversity threshold levels, abundance and biomass were similar and the seasonal variance of zooplankton quantity was significant between the two fish reefs. The abundance of larvae was effected by Copepods and the distribution of fish spawns was decided by hydrologic conditions. The spatio-temporal variation of zooplankton community characteristics, such as biodiversity indices, community structure, abundance and distribution, were response to temperature, salinity and zooplankton distribution caused by seasonal variation of water mass.
Zooplankton community characteristics are related to potential fishery resources and effected by environmental factors in coastal reefs. According to four seasonal cruises on fishery ecology in artificial reefs and island reefs of Daya Bay (114.540°E−114.669°E, 22.540°N−22.639°N) in 2015, we analyzed the zooplankton community characteristics and impacts of environmental factors on ichthyoplankton. Altogether 130 zooplankton species were identified. The community structure of zooplankton experienced seasonal variation, including spring group, summer group, autumn group and winter group. The distinct dominant species were Penilia avirostris and Noctiluca scintillens in spring and summer, and Acartia erythraea and Flaccisagitta enflata in autumn and early winter. The annual means of Margalef index, diversity threshold levels, abundance and biomass were similar and the seasonal variance of zooplankton quantity was significant between the two fish reefs. The abundance of larvae was effected by Copepods and the distribution of fish spawns was decided by hydrologic conditions. The spatio-temporal variation of zooplankton community characteristics, such as biodiversity indices, community structure, abundance and distribution, were response to temperature, salinity and zooplankton distribution caused by seasonal variation of water mass.
2018, 14(2): 51-59.
DOI: 10.3969/j.issn.2095-0780.2018.02.007
Abstract:
To understand the behaviors of restocking and releasing fish, two kinds of restocking and releasing fishes [grey snapper (Lutjanus argentimaculatus) and black snapper (Acanthopagrus schlegelii)] were tracked by using ultrasonic tags at Seven-star Bay in Shenzhen from July 16 to July 31, 2016. The signal of the tags was received by buoy wireless data transmission receivers, and the fish behavior was analyzed preliminarily. A grey snapper and a black snapper had complete data but the other two grey snappers were lost after being tracked for 4 d. Both the grey snapper and the black snapper had obvious circadian rhythm and hiding behavior, active in a small area (about 100 m) near the released place. The data obtained during daytime (7:00–20:00) were significantly less than at night (20:00–7:00). The black snapper was active at 9–10 m layer in daytime and at 8–9 m layer at night; the grey snapper was active at 2–3.5 m layer in daytime and at 1–2 m layer at night. The study promotes application of tracking by tags in fish behavior research and effect evaluation of restocking and releasing and sea ranching construction.
To understand the behaviors of restocking and releasing fish, two kinds of restocking and releasing fishes [grey snapper (Lutjanus argentimaculatus) and black snapper (Acanthopagrus schlegelii)] were tracked by using ultrasonic tags at Seven-star Bay in Shenzhen from July 16 to July 31, 2016. The signal of the tags was received by buoy wireless data transmission receivers, and the fish behavior was analyzed preliminarily. A grey snapper and a black snapper had complete data but the other two grey snappers were lost after being tracked for 4 d. Both the grey snapper and the black snapper had obvious circadian rhythm and hiding behavior, active in a small area (about 100 m) near the released place. The data obtained during daytime (7:00–20:00) were significantly less than at night (20:00–7:00). The black snapper was active at 9–10 m layer in daytime and at 8–9 m layer at night; the grey snapper was active at 2–3.5 m layer in daytime and at 1–2 m layer at night. The study promotes application of tracking by tags in fish behavior research and effect evaluation of restocking and releasing and sea ranching construction.
Abstract:
We studied the influence of triazophos on sex hormone levels, apoptosis, activity of related protease caspase and microstructure of Perna viridis gonad, so as to discuss the endocrine disrupting mechanism and reproductive toxicity of triazophos on P.viridis. The results show that triazophos reduced the contents of β-estradiol and testosterone in gonads of P.viridis (P>0.05), suggesting that triazophos can exert its endocrine-disrupting effects by reducing sex hormones levels. In addition, the response of caspase-3 and caspase-9 activities in the gonads of P.viridis to triazophos exposures were gender-specific. The activities of caspase-3 and caspase-9 in female and male mussels were depressed and induced significantly at different time intervals, respectively, which indicates that triazophos influences the enzyme activity of apoptosis in mussel gonads to affect the apoptosis process. Moreover, the number of reproductive cells decreased and the reproductive cells were more loosely arranged and deformed in P.virudis gonads after triazophos exposure. The results reveal that triazophos shows endocrine disrupting effects and has reproductive toxicity on P.viridis.
We studied the influence of triazophos on sex hormone levels, apoptosis, activity of related protease caspase and microstructure of Perna viridis gonad, so as to discuss the endocrine disrupting mechanism and reproductive toxicity of triazophos on P.viridis. The results show that triazophos reduced the contents of β-estradiol and testosterone in gonads of P.viridis (P>0.05), suggesting that triazophos can exert its endocrine-disrupting effects by reducing sex hormones levels. In addition, the response of caspase-3 and caspase-9 activities in the gonads of P.viridis to triazophos exposures were gender-specific. The activities of caspase-3 and caspase-9 in female and male mussels were depressed and induced significantly at different time intervals, respectively, which indicates that triazophos influences the enzyme activity of apoptosis in mussel gonads to affect the apoptosis process. Moreover, the number of reproductive cells decreased and the reproductive cells were more loosely arranged and deformed in P.virudis gonads after triazophos exposure. The results reveal that triazophos shows endocrine disrupting effects and has reproductive toxicity on P.viridis.
Abstract:
Thymosin β4 has antibacterial properties and inflammation inhibition function which can promote wound healing. This study cloned the gene sequence of Pfthymosin β4 from Pinctada fucata. The total length of the gene was 261 bp, with 126 bp open reading frame encoding 42 amino acids. Bioinformatics analysis reveals that the theoretical molecular weight of Pfthymosin β4 was 4.78 ku, which had typical “THY” motif and thymosin beta family signature sequences. It was highly conserved and had more than 90% similarity to other species. The results of qPCR show that Pfthymosin β4 was expressed in all tissues with the highest expression in hemolymph, followed by foot and gills. Hemolymphs and wound tissues were collected after the mantle-transplantation. The expression of Pfthymosin β4 in hemolymphs and wound tissues increased significantly and reached the maximum at 6th hour, which might be the reason that it promotes hemolymphs to move to the wound to participate in the wound pre-repair. The expression level of Pfthymosin β4, which elevated at metamorphosis stage, was detected at each developmental stage of P.fucata. Therefore, it is speculated that Pfthymosin β4 might be involved in metamorphosis of P.fucata.
Thymosin β4 has antibacterial properties and inflammation inhibition function which can promote wound healing. This study cloned the gene sequence of Pfthymosin β4 from Pinctada fucata. The total length of the gene was 261 bp, with 126 bp open reading frame encoding 42 amino acids. Bioinformatics analysis reveals that the theoretical molecular weight of Pfthymosin β4 was 4.78 ku, which had typical “THY” motif and thymosin beta family signature sequences. It was highly conserved and had more than 90% similarity to other species. The results of qPCR show that Pfthymosin β4 was expressed in all tissues with the highest expression in hemolymph, followed by foot and gills. Hemolymphs and wound tissues were collected after the mantle-transplantation. The expression of Pfthymosin β4 in hemolymphs and wound tissues increased significantly and reached the maximum at 6th hour, which might be the reason that it promotes hemolymphs to move to the wound to participate in the wound pre-repair. The expression level of Pfthymosin β4, which elevated at metamorphosis stage, was detected at each developmental stage of P.fucata. Therefore, it is speculated that Pfthymosin β4 might be involved in metamorphosis of P.fucata.
2018, 14(2): 75-82.
DOI: 10.3969/j.issn.2095-0780.2018.02.010
Abstract:
Vibrio harveyi is one of the most important mariculture pathogens. We amplified the whole rbsB gene (GenBank ID MF797015) sequence of V.harveyi strain 354 which was predicted to encode 292 amino acid with molecular weight of 30.7 kD, isoelectric point of 5.05 and hydrophilic coefficient of 0.043. Thus, the Vh-RbsB may be a hydrophobic protein. Phylogenetic tree constructed based on RbsB amino acid sequence indicates that Vh-RbsB has the closest relationship with V.owensii CAIM 1854. A recombinant plasmid pGEX-4t-1-rbsB was constructed and transformed into Escherichia coli BL21 (DE3). The relative molecular weight of the recombinant protein was about 59 kD. The highest expression was observed at 37 ℃, 8 h, concentration of IPTG of 0.6 mmol·L–1.
Vibrio harveyi is one of the most important mariculture pathogens. We amplified the whole rbsB gene (GenBank ID MF797015) sequence of V.harveyi strain 354 which was predicted to encode 292 amino acid with molecular weight of 30.7 kD, isoelectric point of 5.05 and hydrophilic coefficient of 0.043. Thus, the Vh-RbsB may be a hydrophobic protein. Phylogenetic tree constructed based on RbsB amino acid sequence indicates that Vh-RbsB has the closest relationship with V.owensii CAIM 1854. A recombinant plasmid pGEX-4t-1-rbsB was constructed and transformed into Escherichia coli BL21 (DE3). The relative molecular weight of the recombinant protein was about 59 kD. The highest expression was observed at 37 ℃, 8 h, concentration of IPTG of 0.6 mmol·L–1.
Abstract:
The tilapia (GIFT Oreochromis niloticus) with initial body mass of (74.36±5.32) g were fed by diets at six myo-inositol (MI) levels (0 mg·kg–1 , 100 mg·kg–1, 200 mg·kg–1, 400 mg·kg–1, 800 mg·kg–1 and 1 600 mg·kg–1 ) diets for 12 weeks, so as to investigate the effect of MI on tilapia. We measured their growth performance, body composition and serum biochemical indices, and finally determined the requirement of dietary MI for large size GIFT O.niloticus. The results show that the dietary MI increased the weight gain rate (WGR), feed intake and feed conversion ratio significantly compared with the control group (P<0.05). According to the second-order polynomial regression analyses based on WGR and dietary MI level, the optimum MI requirement was 847 mg·kg–1. The crude fat contents in the liver, muscle and whole body of tilapia decreased with increasing dietary MI level, but the crude protein contents in muscle and liver showed no significant difference among groups (P>0.05). The activities of aspartate aminotransferase and alanine aminotransferase in serum were significantly lower in 800 mg·kg–1 and 1 600 mg·kg–1 MI groups than those in the control (P<0.05). With increasing dietary MI level, the total cholesterol and triacylglyceroln contents in serum firstly deceased and then increased, but the glucose contents in serum showed an opposite trend. In conclusion, the diet with 847 mg·kg–1 MI is optimal for large size GIFT O.niloticus, and appropriate dietary MI supplementation is beneficial to reducing tissue fat accumulation and improving liver function.
The tilapia (GIFT Oreochromis niloticus) with initial body mass of (74.36±5.32) g were fed by diets at six myo-inositol (MI) levels (0 mg·kg–1 , 100 mg·kg–1, 200 mg·kg–1, 400 mg·kg–1, 800 mg·kg–1 and 1 600 mg·kg–1 ) diets for 12 weeks, so as to investigate the effect of MI on tilapia. We measured their growth performance, body composition and serum biochemical indices, and finally determined the requirement of dietary MI for large size GIFT O.niloticus. The results show that the dietary MI increased the weight gain rate (WGR), feed intake and feed conversion ratio significantly compared with the control group (P<0.05). According to the second-order polynomial regression analyses based on WGR and dietary MI level, the optimum MI requirement was 847 mg·kg–1. The crude fat contents in the liver, muscle and whole body of tilapia decreased with increasing dietary MI level, but the crude protein contents in muscle and liver showed no significant difference among groups (P>0.05). The activities of aspartate aminotransferase and alanine aminotransferase in serum were significantly lower in 800 mg·kg–1 and 1 600 mg·kg–1 MI groups than those in the control (P<0.05). With increasing dietary MI level, the total cholesterol and triacylglyceroln contents in serum firstly deceased and then increased, but the glucose contents in serum showed an opposite trend. In conclusion, the diet with 847 mg·kg–1 MI is optimal for large size GIFT O.niloticus, and appropriate dietary MI supplementation is beneficial to reducing tissue fat accumulation and improving liver function.
Abstract:
To investigate the effects of short-term starvation on the morphometriacal, textural parameters and nutritional composition of channel catfish (Ictalurus punctatus) of commercial specification, we starved the fish for 0 d (S0), 5 d (S5), 10 d (S10), 15 d (S15) and 20 d (S20) at (21.5±1) ℃. The results show that the condition factor (CF), viscerosomatic index (VSI) and hepatosomatic index (HSI) decreased significantly with the starvation time (P<0.05). The mass fractions of protein and lipid in muscle decreased significantly (P<0.05), while the water mass fraction increased. The ash mass fraction decreased in the first ten-day starvation and then increased in the following ten-day starvation (P<0.05). The muscle hardness decreased while the muscle cohesiveness and springiness index increased significantly (P<0.05). The amino acid mass fraction did not show significant difference between Group S0 and Group S20 (P>0.05). Compared with Group S0, the mass fractions of the saturated fatty acid (SFA), total unsaturated fatty acid (UFA), monosaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) in Group S20 decreased about 17.1%, 10.9%, 10.1% and 12.3%, respectively. No significant difference was found in mass fractions of EPA and DHA during the duration of starvation (P>0.05).
To investigate the effects of short-term starvation on the morphometriacal, textural parameters and nutritional composition of channel catfish (Ictalurus punctatus) of commercial specification, we starved the fish for 0 d (S0), 5 d (S5), 10 d (S10), 15 d (S15) and 20 d (S20) at (21.5±1) ℃. The results show that the condition factor (CF), viscerosomatic index (VSI) and hepatosomatic index (HSI) decreased significantly with the starvation time (P<0.05). The mass fractions of protein and lipid in muscle decreased significantly (P<0.05), while the water mass fraction increased. The ash mass fraction decreased in the first ten-day starvation and then increased in the following ten-day starvation (P<0.05). The muscle hardness decreased while the muscle cohesiveness and springiness index increased significantly (P<0.05). The amino acid mass fraction did not show significant difference between Group S0 and Group S20 (P>0.05). Compared with Group S0, the mass fractions of the saturated fatty acid (SFA), total unsaturated fatty acid (UFA), monosaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) in Group S20 decreased about 17.1%, 10.9%, 10.1% and 12.3%, respectively. No significant difference was found in mass fractions of EPA and DHA during the duration of starvation (P>0.05).
2018, 14(2): 96-101.
DOI: 10.3969/j.issn.2095-0780.2018.02.013
Abstract:
The parent fish of Siganus oramin were bred in deep-sea anti-wave cage. We selected the 1+ aged parent fish with mature sex glands for spawning artificially and dry insehation. The fertilized eggs obtained were incubated in laboratory for observation of the whole process of embryo development. The results show that the ovulation and insemination behavior of cage-breeding S.oramin still remained a strict rhythm of the calendar after being induced spawning in a cement pool. The mature zygote of S.oramin was heavy, sticky and round with multi-oil ball, and the egg membrane was smooth and ooplasm transparent. The diameter of zygote was (584.6±8.64) μm, and the maximum oil ball diameter was (146.54±7.46) μm. The first larvae hatch finished at 39th hour 20 min under 23.2–24.5 ℃ at salinity 32.5 and pH 8.2. All fertilized eggs completed incubation at 42nd h 10 min with accumulated temperature of 925.28–996.45 ℃·h. According to morphological characteristics, the process of embryonic development could be divided into seven physiological stages with 26 periods: blastoderm form stage, cleavage stage, blastula stage, gastrula stage, neural stage, organogenesis stage and hatching stage. The body length of newly hatched larvae was (1 912.54±105.25) μm; the larvae opened mouth at 2.5 dph (56 h after incubation) with total length of (3 030.36±80.97) μm.
The parent fish of Siganus oramin were bred in deep-sea anti-wave cage. We selected the 1+ aged parent fish with mature sex glands for spawning artificially and dry insehation. The fertilized eggs obtained were incubated in laboratory for observation of the whole process of embryo development. The results show that the ovulation and insemination behavior of cage-breeding S.oramin still remained a strict rhythm of the calendar after being induced spawning in a cement pool. The mature zygote of S.oramin was heavy, sticky and round with multi-oil ball, and the egg membrane was smooth and ooplasm transparent. The diameter of zygote was (584.6±8.64) μm, and the maximum oil ball diameter was (146.54±7.46) μm. The first larvae hatch finished at 39th hour 20 min under 23.2–24.5 ℃ at salinity 32.5 and pH 8.2. All fertilized eggs completed incubation at 42nd h 10 min with accumulated temperature of 925.28–996.45 ℃·h. According to morphological characteristics, the process of embryonic development could be divided into seven physiological stages with 26 periods: blastoderm form stage, cleavage stage, blastula stage, gastrula stage, neural stage, organogenesis stage and hatching stage. The body length of newly hatched larvae was (1 912.54±105.25) μm; the larvae opened mouth at 2.5 dph (56 h after incubation) with total length of (3 030.36±80.97) μm.
Abstract:
We investigated the effects of three kinds of non-muscle protein additives [soybean protein isolation (SPI), gluten powder (GP) and whey protein (WP)] on the quality of partial frozen Coregouns peled muscle by texture profile analysis and scanning electron microscopic observation. The pH values of all samples showed a decrease-increase trend. Meanwhile, the electroconductivity and adhesiveness showed an increasing trend as the storage time goes, while the water-holding capacity, hardness, springiness, cohesiveness, chewiness and resilience decreased. However, the SPI, GP and WP additives reduced the quality deterioration of C.peled muscle during partially frozen storage, and GP presented a significant inhibitory effect (P<0.05). The scanning electron microscope observation reveals that the muscle tissues of samples in the control group were destroyed seriously as the storage time goes, but not for the muscle structure of the samples with three kinds of non-muscle protein additives, and the pore size changed little. The GP addition samples maintained tight tissue structure. Thus, it is indicated that the addition of SPI, GP and WP can reduce the deterioration rate of C.peled muscle effectively during partially frozen storage, and GP additive had better effect.
We investigated the effects of three kinds of non-muscle protein additives [soybean protein isolation (SPI), gluten powder (GP) and whey protein (WP)] on the quality of partial frozen Coregouns peled muscle by texture profile analysis and scanning electron microscopic observation. The pH values of all samples showed a decrease-increase trend. Meanwhile, the electroconductivity and adhesiveness showed an increasing trend as the storage time goes, while the water-holding capacity, hardness, springiness, cohesiveness, chewiness and resilience decreased. However, the SPI, GP and WP additives reduced the quality deterioration of C.peled muscle during partially frozen storage, and GP presented a significant inhibitory effect (P<0.05). The scanning electron microscope observation reveals that the muscle tissues of samples in the control group were destroyed seriously as the storage time goes, but not for the muscle structure of the samples with three kinds of non-muscle protein additives, and the pore size changed little. The GP addition samples maintained tight tissue structure. Thus, it is indicated that the addition of SPI, GP and WP can reduce the deterioration rate of C.peled muscle effectively during partially frozen storage, and GP additive had better effect.
Abstract:
According to the fish resources data collected in Dawangtan Reservoir from November 2016 to August 2017, we investigated the present situation, species composition, dominant species and diversity of wild fish resources in this reservoir. Thirty-four species belonging to 4 orders, 9 families and 26 genera have been identified. Cyprinidae, which accounted for 64.71% of all species and 48.15% of all individuals, was most abundant. According to the analysis of relative importance index (IRI), the most dominant species were Oreochromis niloticus, Cyprinus carpio, Cirrhinus molitorella and O.mossambicus. The Shannon-Wiener species diversity index (H') was 1.213~2.279; the Margalef index (D) was 1.995~3.412; the Pielou evenness index (J') was 0.448~0.771; the Simpson index (C) was 0.120~0.507, which was highest in S3 station but relatively lower in S1 station. The fish species diversity in summer was highest, and that in winter was lowest.Cluster analysis and analysis of similarity (ANOSIM) show no significant difference in the fish communities among seasons and sampling sites. An obvious decreasing trend was found in the number of types of fish resources and the alien species invasion in Dawangtan Reservoir.
According to the fish resources data collected in Dawangtan Reservoir from November 2016 to August 2017, we investigated the present situation, species composition, dominant species and diversity of wild fish resources in this reservoir. Thirty-four species belonging to 4 orders, 9 families and 26 genera have been identified. Cyprinidae, which accounted for 64.71% of all species and 48.15% of all individuals, was most abundant. According to the analysis of relative importance index (IRI), the most dominant species were Oreochromis niloticus, Cyprinus carpio, Cirrhinus molitorella and O.mossambicus. The Shannon-Wiener species diversity index (H') was 1.213~2.279; the Margalef index (D) was 1.995~3.412; the Pielou evenness index (J') was 0.448~0.771; the Simpson index (C) was 0.120~0.507, which was highest in S3 station but relatively lower in S1 station. The fish species diversity in summer was highest, and that in winter was lowest.Cluster analysis and analysis of similarity (ANOSIM) show no significant difference in the fish communities among seasons and sampling sites. An obvious decreasing trend was found in the number of types of fish resources and the alien species invasion in Dawangtan Reservoir.
Abstract:
We evaluated the killing effects of water extracts of six Chinese herbal medicines on Crytocaryon irritans in vitro, and found out that treating theronts for 5 min with 7.14 mg·mL–1 of Fructus mume, Areca catechu, Dryopteris setosa and Punica granatum, respectively, had rendered the theronts mortality rate of 100%. Moreover, treating tomonts with the above water extracts at a concentration of 28.57 mg·mL–1 for 4 h could lead to the tomonts mortality rate of over 84.1%. To evaluate the preventive effect of water extract of F.mume on C.irritans infection, we studied the weight gain, lysozyme activity, hemolytic activity of alternative pathway CH50 (ACH50), number of fish trophozoites and mortality rate of Epinephelus lanceolatus♀×E.fuscoguttatus♂ after having fed with water extract of F.mume for 14 d. No significant difference was observed in weight gain and hemolytic activity of ACH50 between medicine groups and control group (P>0.05). In addition, lysozyme activity was all significantly higher than that in control group (P<0.05), and number of trophozoites after infection with C.irritans was significantly lower than that in control group (P<0.05). Furthermore, the survival rate in medicine groups (11.4 g·kg–1, 6.84 g·kg–1, 3.42 g·kg–1) and the control group were 40%, 20%, 46.67% and 0% with lethal dose infection, respectively. It is indicated that F.mume has developmental prospects for preventing C.irritans infection.
We evaluated the killing effects of water extracts of six Chinese herbal medicines on Crytocaryon irritans in vitro, and found out that treating theronts for 5 min with 7.14 mg·mL–1 of Fructus mume, Areca catechu, Dryopteris setosa and Punica granatum, respectively, had rendered the theronts mortality rate of 100%. Moreover, treating tomonts with the above water extracts at a concentration of 28.57 mg·mL–1 for 4 h could lead to the tomonts mortality rate of over 84.1%. To evaluate the preventive effect of water extract of F.mume on C.irritans infection, we studied the weight gain, lysozyme activity, hemolytic activity of alternative pathway CH50 (ACH50), number of fish trophozoites and mortality rate of Epinephelus lanceolatus♀×E.fuscoguttatus♂ after having fed with water extract of F.mume for 14 d. No significant difference was observed in weight gain and hemolytic activity of ACH50 between medicine groups and control group (P>0.05). In addition, lysozyme activity was all significantly higher than that in control group (P<0.05), and number of trophozoites after infection with C.irritans was significantly lower than that in control group (P<0.05). Furthermore, the survival rate in medicine groups (11.4 g·kg–1, 6.84 g·kg–1, 3.42 g·kg–1) and the control group were 40%, 20%, 46.67% and 0% with lethal dose infection, respectively. It is indicated that F.mume has developmental prospects for preventing C.irritans infection.
Abstract:
According to the survey data of the investigation of offshore resources in the northern South China Sea during 2014−2015, we analyzed the relationship among the fishing ground, vertical structure of temperature and water temperature in that area. The results show that the location of fishing ground was closely related to water temperature gradient, and the correlation coefficient of location of fishing ground and temperature gradient was different in different seasons. The correlation between location of fishing ground and temperature gradients of 20−25 m water layer was the highest in spring survey. There was high correlation between location of fishing ground and at the surface layer and 50 m water layer in summer survey. The location of fishing ground was closely related to the water layer of 10−15 m in autumn survey, and the correlation between fishing location and temperature gradient at 15−20 m water layer was the highest in winter survey. It is also found that the fishing ground of the northern South China Sea was sensitive to the change of water temperature gradient. The fishing ground was mainly located in the Beibu Gulf in spring and summer, and mainly in the sea area near the east of Hainan Island in Leizhou Peninsula during autumn and winter.
According to the survey data of the investigation of offshore resources in the northern South China Sea during 2014−2015, we analyzed the relationship among the fishing ground, vertical structure of temperature and water temperature in that area. The results show that the location of fishing ground was closely related to water temperature gradient, and the correlation coefficient of location of fishing ground and temperature gradient was different in different seasons. The correlation between location of fishing ground and temperature gradients of 20−25 m water layer was the highest in spring survey. There was high correlation between location of fishing ground and at the surface layer and 50 m water layer in summer survey. The location of fishing ground was closely related to the water layer of 10−15 m in autumn survey, and the correlation between fishing location and temperature gradient at 15−20 m water layer was the highest in winter survey. It is also found that the fishing ground of the northern South China Sea was sensitive to the change of water temperature gradient. The fishing ground was mainly located in the Beibu Gulf in spring and summer, and mainly in the sea area near the east of Hainan Island in Leizhou Peninsula during autumn and winter.