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Paul K S Shin - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids from controlled feeding as dietary markers of juvenile chinese horseshoe crab Tachypleus tridentatus
    Journal of the Marine Biological Association of the United Kingdom, 2019
    Co-Authors: Billy K Y Kwan, Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    The potential use of fatty acid (FA) profile as a dietary tracer in juvenile Chinese horseshoe crab Tachypleus tridentatus was assessed in a feeding experiment. Selected feed was provided to the juveniles at various growth stages according to their food sources in the wild: larval and adult brine shrimp Artemia salina for the first six months, followed by a mixture of short-neck clam Ruditapes philippinarum and greasyback shrimp Metapenaeus ensis for a further six months. Juvenile horseshoe crab haemolymph and tissues of book gill, opisthosomal spine, chelicera and swimming leg were sampled after the feeding experiment. The FA profiles revealed that the juvenile haemolymph and various tissues had a total of 23–24 FA components. The major FA components consisted of saturated (palmitic and stearic) at 22–34%, monosaturated (oleic) at 7–34% and polyunsaturated (eicosapentaenoic and arachidonic) FAs at 9–27%. According to principal component analysis, the FA signatures of juvenile haemolymph were greatly influenced by the shift of food sources from brine shrimp to clam and shrimp meat, whereas the FA profiles of different tissues were more resistant to the nutrient alteration. The present findings confirmed that the FA profile of both juvenile haemolymph and different tissues reflected the FA composition of recent and previous diets, respectively; and thus may be useful in indicating the foraging information of juvenile horseshoe crabs in the field.

  • responses of growth and hemolymph quality in juvenile chinese horseshoe crab Tachypleus tridentatus xiphosura to sublethal tributyltin and cadmium
    Ecotoxicology, 2015
    Co-Authors: Billy K Y Kwan, S G Cheung, Alice K Y Chan, Paul K S Shin
    Abstract:

    Responses of growth endpoints and hemolymph constituents in juvenile Chinese horseshoe crab Tachypleus tridentatus under treatments of 0.01 and 0.1 mg/l tributyltin (TBT) and 0.1 and 1 mg/l cadmium (Cd) were examined in a 12-week experiment. A significant decline in final body weight, final prosomal width, percentage of individuals molted and mean molting time was detected under TBT exposures. While morphological abnormalities of the juveniles between TBT treatments and the control were statistically indistinguishable, significantly higher occurrences of carapace erosion and appendage loss were noted under 0.1 and 1 mg/l Cd exposures. Various hemolymph quality indicators, including hemolymph plasma protein level, amebocyte viability and percentage of granular-spherical state of amebocytes of the juveniles exposed to TBT or Cd were significantly lower than the control. Such a decrease in hemolymph quality suggested deleterious effects of metal contaminant-induced stressors on the health status of the juveniles even at low exposure levels (i.e., 0.01 mg/l TBT and 0.1 mg/l Cd). Changes of hemolymph parameters in juvenile horseshoe crabs were more sensitive than growth performance as well as morphological abnormalities in response to metal stressors, and can be used as an indicator to reflect habitat conditions and contaminant levels.

  • preliminary home range study of juvenile chinese horseshoe crabs Tachypleus tridentatus xiphosura using passive tracking methods
    2015
    Co-Authors: Billy K Y Kwan, Paul K S Shin, S G Cheung
    Abstract:

    Three passive tracking methods, using colored plastic tag (CPT), passive integrated transponder (PIT) tag, and CPT plus PIT were compared to track the movements of juvenile Chinese horseshoe crabs, Tachypleus tridentatus, in summer 2013 on a mudflat in Hong Kong. The study site was re-visited within 2 months after the release of the tagged individuals on ten occasions during low tides. The cumulative recovery rates of the tagged juveniles ranged from 70 to 82 %, with the number of position fixes where each individual was recovered during the repeated field visits varying from one to seven. Based on the adaptive kernel density estimation approach, the mean home range size (indicated by 95 % utilization distribution) tracked by different methods varied between 269 and 462 m2. While the effects of tracking methods on home range size of the juveniles were statistically indistinguishable, PIT tags could be used as a longer-term tracking device for juvenile horseshoe crabs because the tag injected into animal bodies did not cause noticeable effects on survival, growth and molting. Within the body size range of 7th–10th instar juveniles (prosomal width 31–59 mm) used in the present study, no significant correlation was found between body size and home range area. From the analysis of utilization distribution, the juveniles were noted to exhibit residential and nomadic movement patterns, which might be associated with the distribution of food patches on the mudflat. The restricted movements of juveniles in this study suggest potential for high susceptibility to localized habitat disturbance.

  • population structure and growth of juvenile horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda xiphosura in southern china
    2015
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Billy K Y Kwan, Paul K S Shin
    Abstract:

    The abundance, population structure and growth of juvenile Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda are rarely reported in the literature. This study investigated the density and growth allometry of these sympatric species on the intertidal areas of three spawning and nursery beaches, Xi Bei Ling (XBL), Jin Hai Wan (JHW) and Xi Chang (XC) along the coast of Beibu Gulf, southern China. While T. tridentatus and C. rotundicauda coexisted on JHW and XC beaches, only T. tridentatus was found at XBL. The density of T. tridentatus (0.9–3.2 individuals/100 m2) was significantly higher than that of C. rotundicauda (0.1–1.7 individuals/100 m2) at JHW, but densities were similar at XC. Juvenile T. tridentatus ranged in size (prosomal width) from 14 to 89 mm and were estimated to represent instars 4–12 and ages 2–8 years based on previous studies. C. rotundicauda juveniles were 16–75 mm in prosomal width and represented instars 5–15. The Hiatt growth model on the relationship between pre- and post-molt size data showed similar growth increments in juvenile T. tridentatus and C. rotundicauda. Growth rates for T. tridentatus varied from 4.4 to 19.7 mm/year, depending on instar stage and site. Growth rates were not determined for C. rotundicauda due to lack of data. These data establish a baseline for density and growth allometry of juvenile T. tridentatus and C. rotundicauda horseshoe crabs in Asian waters and will support future monitoring and assessment of juvenile populations and habitat resources.

  • digestible dietary protein and energy requirements of juvenile asian horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda
    Aquaculture Research, 2014
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    A 84-day feeding experiment of two juvenile horseshoe crab species, including nine formulated diets with three digestible protein (DP) levels (36%, 40% and 44%) and three digestible energy (DE) levels (14, 16 and 18 kJ g−1) versus the control, fed on frozen brine shrimp (Artemia salina), was conducted. The results showed that the survival rate of Tachypleus tridentatus ranged from 67% to 100%, while that of Carcinoscorpius rotundicauda varied from 44% to 100%. The results also indicated that the formulated diet containing 40% DP with 14 kJ g−1 DE was the best, in terms of growth and feed utilization, for the two juvenile horseshoe crab species. Final body weight (FBW), thermal-unit growth coefficient (TGC), feed efficiency (FE), nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) of T. tridentatus fed 40% DP and 14 kJ g−1 DE were significantly higher than that of T. tridentatus fed the control diet. However, for C. rotundicauda, only significantly higher FE, NRE and ERE were found in juveniles fed 40% DP and 14 kJ g−1 DE than the control diet. The present findings revealed that the optimum DP/DE ratio for the two species was 28 g protein MJ−1.

Menghong Hu - One of the best experts on this subject based on the ideXlab platform.

  • effects of copper supplement on the immune function and blood chemistry in adult chinese horseshoe crab Tachypleus tridentatus
    Aquaculture, 2020
    Co-Authors: Zhen Xu, Qiongzhen Li, Jie Song, Youji Wang, Menghong Hu
    Abstract:

    Abstract Oxygen in hemocyanin binds to copper ions and turns the hemolymph of horseshoe crabs blue. Copper ions not only transport oxygen but also enhance the immune function of horseshoe crabs. A 28-day indoor culture experiment was conducted to study the effects of adding different levels of copper amino acid chelate (0, 50, or 100 mg kg−1) into semi-finished feed on the nonspecific immune enzyme activity and hemolymph biochemical parameters of Tachypleus tridentatus. Results revealed that the activities of serum antioxidant enzyme indicators, namely, copper–zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GPX), total antioxidant capacity (T-AOC), lysozyme (LZM), alkaline phosphatase (AKP), and acid phosphatase (ACP), of copper-fed adult horseshoe crabs increased; on the other hand, malondialdehyde (MDA) activity decreased. Hemolymph biochemical indicators, triglyceride (TG) and cholesterol (CHO) decreased in the copper-fed group, but hemocyanin concentration (HC) levels increased during the experiment. At the end of experiment, all antioxidant enzymes and blood biochemical indicators in the copper-fed group were significantly different from those without copper supplement. Hemolymph T-AOC, MDA, AKP, ACP values in the low-level copper group (50 mg kg−1) were significantly different from those in the high-level copper group (100 mg kg−1).

  • classification and characterization of hemocytes from two asian horseshoe crab species Tachypleus tridentatus and carcinoscorpius rotundicauda
    Scientific Reports, 2019
    Co-Authors: Qiongzhen Li, Fangli Wu, Jie Song, Menghong Hu, Youji Wang
    Abstract:

    In present study, transmission electron microscopy and flow cytometry were utilized to investigate the classification, characterization and immune functions of hemocytes from horseshoe crab, Tachypleus tridentatus and Carcinoscorpius rotundicauda. Three types of hemocytes were distinguished respectively: the granular cell, the semi-granular cell and the hyaline cell by transmission electron microscopy, while three hemocyte subpopulations (Gate 1 cell, Gate 2 cell, Gate 3 cell) were classified by flow cytometry. Hyaline cell was the major cell type with the highest nuclear-cytoplasmic ratio and granular cell and semi-granular cell showed lower ratios. Immune parameters of hemocytes in horseshoe crabs were investigated by flow cytometry. Different hemocyte subpopulations respond for diverse functions. Lysosomal contents and hemocyte mortality in Gate 3 cell subpopulation were higher than that in other subpopulations, while reactive oxygen species, phagocytosis and non-specific esterase, in Gate 1 cell subpopulation, were higher than those in other subpopulations. The hemocyte types between the two species had no significant differences in staining or morphology.

  • fatty acids from controlled feeding as dietary markers of juvenile chinese horseshoe crab Tachypleus tridentatus
    Journal of the Marine Biological Association of the United Kingdom, 2019
    Co-Authors: Billy K Y Kwan, Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    The potential use of fatty acid (FA) profile as a dietary tracer in juvenile Chinese horseshoe crab Tachypleus tridentatus was assessed in a feeding experiment. Selected feed was provided to the juveniles at various growth stages according to their food sources in the wild: larval and adult brine shrimp Artemia salina for the first six months, followed by a mixture of short-neck clam Ruditapes philippinarum and greasyback shrimp Metapenaeus ensis for a further six months. Juvenile horseshoe crab haemolymph and tissues of book gill, opisthosomal spine, chelicera and swimming leg were sampled after the feeding experiment. The FA profiles revealed that the juvenile haemolymph and various tissues had a total of 23–24 FA components. The major FA components consisted of saturated (palmitic and stearic) at 22–34%, monosaturated (oleic) at 7–34% and polyunsaturated (eicosapentaenoic and arachidonic) FAs at 9–27%. According to principal component analysis, the FA signatures of juvenile haemolymph were greatly influenced by the shift of food sources from brine shrimp to clam and shrimp meat, whereas the FA profiles of different tissues were more resistant to the nutrient alteration. The present findings confirmed that the FA profile of both juvenile haemolymph and different tissues reflected the FA composition of recent and previous diets, respectively; and thus may be useful in indicating the foraging information of juvenile horseshoe crabs in the field.

  • population structure and growth of juvenile horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda xiphosura in southern china
    2015
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Billy K Y Kwan, Paul K S Shin
    Abstract:

    The abundance, population structure and growth of juvenile Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda are rarely reported in the literature. This study investigated the density and growth allometry of these sympatric species on the intertidal areas of three spawning and nursery beaches, Xi Bei Ling (XBL), Jin Hai Wan (JHW) and Xi Chang (XC) along the coast of Beibu Gulf, southern China. While T. tridentatus and C. rotundicauda coexisted on JHW and XC beaches, only T. tridentatus was found at XBL. The density of T. tridentatus (0.9–3.2 individuals/100 m2) was significantly higher than that of C. rotundicauda (0.1–1.7 individuals/100 m2) at JHW, but densities were similar at XC. Juvenile T. tridentatus ranged in size (prosomal width) from 14 to 89 mm and were estimated to represent instars 4–12 and ages 2–8 years based on previous studies. C. rotundicauda juveniles were 16–75 mm in prosomal width and represented instars 5–15. The Hiatt growth model on the relationship between pre- and post-molt size data showed similar growth increments in juvenile T. tridentatus and C. rotundicauda. Growth rates for T. tridentatus varied from 4.4 to 19.7 mm/year, depending on instar stage and site. Growth rates were not determined for C. rotundicauda due to lack of data. These data establish a baseline for density and growth allometry of juvenile T. tridentatus and C. rotundicauda horseshoe crabs in Asian waters and will support future monitoring and assessment of juvenile populations and habitat resources.

  • digestible dietary protein and energy requirements of juvenile asian horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda
    Aquaculture Research, 2014
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    A 84-day feeding experiment of two juvenile horseshoe crab species, including nine formulated diets with three digestible protein (DP) levels (36%, 40% and 44%) and three digestible energy (DE) levels (14, 16 and 18 kJ g−1) versus the control, fed on frozen brine shrimp (Artemia salina), was conducted. The results showed that the survival rate of Tachypleus tridentatus ranged from 67% to 100%, while that of Carcinoscorpius rotundicauda varied from 44% to 100%. The results also indicated that the formulated diet containing 40% DP with 14 kJ g−1 DE was the best, in terms of growth and feed utilization, for the two juvenile horseshoe crab species. Final body weight (FBW), thermal-unit growth coefficient (TGC), feed efficiency (FE), nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) of T. tridentatus fed 40% DP and 14 kJ g−1 DE were significantly higher than that of T. tridentatus fed the control diet. However, for C. rotundicauda, only significantly higher FE, NRE and ERE were found in juveniles fed 40% DP and 14 kJ g−1 DE than the control diet. The present findings revealed that the optimum DP/DE ratio for the two species was 28 g protein MJ−1.

Youji Wang - One of the best experts on this subject based on the ideXlab platform.

  • effects of copper supplement on the immune function and blood chemistry in adult chinese horseshoe crab Tachypleus tridentatus
    Aquaculture, 2020
    Co-Authors: Zhen Xu, Qiongzhen Li, Jie Song, Youji Wang, Menghong Hu
    Abstract:

    Abstract Oxygen in hemocyanin binds to copper ions and turns the hemolymph of horseshoe crabs blue. Copper ions not only transport oxygen but also enhance the immune function of horseshoe crabs. A 28-day indoor culture experiment was conducted to study the effects of adding different levels of copper amino acid chelate (0, 50, or 100 mg kg−1) into semi-finished feed on the nonspecific immune enzyme activity and hemolymph biochemical parameters of Tachypleus tridentatus. Results revealed that the activities of serum antioxidant enzyme indicators, namely, copper–zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GPX), total antioxidant capacity (T-AOC), lysozyme (LZM), alkaline phosphatase (AKP), and acid phosphatase (ACP), of copper-fed adult horseshoe crabs increased; on the other hand, malondialdehyde (MDA) activity decreased. Hemolymph biochemical indicators, triglyceride (TG) and cholesterol (CHO) decreased in the copper-fed group, but hemocyanin concentration (HC) levels increased during the experiment. At the end of experiment, all antioxidant enzymes and blood biochemical indicators in the copper-fed group were significantly different from those without copper supplement. Hemolymph T-AOC, MDA, AKP, ACP values in the low-level copper group (50 mg kg−1) were significantly different from those in the high-level copper group (100 mg kg−1).

  • classification and characterization of hemocytes from two asian horseshoe crab species Tachypleus tridentatus and carcinoscorpius rotundicauda
    Scientific Reports, 2019
    Co-Authors: Qiongzhen Li, Fangli Wu, Jie Song, Menghong Hu, Youji Wang
    Abstract:

    In present study, transmission electron microscopy and flow cytometry were utilized to investigate the classification, characterization and immune functions of hemocytes from horseshoe crab, Tachypleus tridentatus and Carcinoscorpius rotundicauda. Three types of hemocytes were distinguished respectively: the granular cell, the semi-granular cell and the hyaline cell by transmission electron microscopy, while three hemocyte subpopulations (Gate 1 cell, Gate 2 cell, Gate 3 cell) were classified by flow cytometry. Hyaline cell was the major cell type with the highest nuclear-cytoplasmic ratio and granular cell and semi-granular cell showed lower ratios. Immune parameters of hemocytes in horseshoe crabs were investigated by flow cytometry. Different hemocyte subpopulations respond for diverse functions. Lysosomal contents and hemocyte mortality in Gate 3 cell subpopulation were higher than that in other subpopulations, while reactive oxygen species, phagocytosis and non-specific esterase, in Gate 1 cell subpopulation, were higher than those in other subpopulations. The hemocyte types between the two species had no significant differences in staining or morphology.

  • fatty acids from controlled feeding as dietary markers of juvenile chinese horseshoe crab Tachypleus tridentatus
    Journal of the Marine Biological Association of the United Kingdom, 2019
    Co-Authors: Billy K Y Kwan, Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    The potential use of fatty acid (FA) profile as a dietary tracer in juvenile Chinese horseshoe crab Tachypleus tridentatus was assessed in a feeding experiment. Selected feed was provided to the juveniles at various growth stages according to their food sources in the wild: larval and adult brine shrimp Artemia salina for the first six months, followed by a mixture of short-neck clam Ruditapes philippinarum and greasyback shrimp Metapenaeus ensis for a further six months. Juvenile horseshoe crab haemolymph and tissues of book gill, opisthosomal spine, chelicera and swimming leg were sampled after the feeding experiment. The FA profiles revealed that the juvenile haemolymph and various tissues had a total of 23–24 FA components. The major FA components consisted of saturated (palmitic and stearic) at 22–34%, monosaturated (oleic) at 7–34% and polyunsaturated (eicosapentaenoic and arachidonic) FAs at 9–27%. According to principal component analysis, the FA signatures of juvenile haemolymph were greatly influenced by the shift of food sources from brine shrimp to clam and shrimp meat, whereas the FA profiles of different tissues were more resistant to the nutrient alteration. The present findings confirmed that the FA profile of both juvenile haemolymph and different tissues reflected the FA composition of recent and previous diets, respectively; and thus may be useful in indicating the foraging information of juvenile horseshoe crabs in the field.

  • population structure and growth of juvenile horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda xiphosura in southern china
    2015
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Billy K Y Kwan, Paul K S Shin
    Abstract:

    The abundance, population structure and growth of juvenile Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda are rarely reported in the literature. This study investigated the density and growth allometry of these sympatric species on the intertidal areas of three spawning and nursery beaches, Xi Bei Ling (XBL), Jin Hai Wan (JHW) and Xi Chang (XC) along the coast of Beibu Gulf, southern China. While T. tridentatus and C. rotundicauda coexisted on JHW and XC beaches, only T. tridentatus was found at XBL. The density of T. tridentatus (0.9–3.2 individuals/100 m2) was significantly higher than that of C. rotundicauda (0.1–1.7 individuals/100 m2) at JHW, but densities were similar at XC. Juvenile T. tridentatus ranged in size (prosomal width) from 14 to 89 mm and were estimated to represent instars 4–12 and ages 2–8 years based on previous studies. C. rotundicauda juveniles were 16–75 mm in prosomal width and represented instars 5–15. The Hiatt growth model on the relationship between pre- and post-molt size data showed similar growth increments in juvenile T. tridentatus and C. rotundicauda. Growth rates for T. tridentatus varied from 4.4 to 19.7 mm/year, depending on instar stage and site. Growth rates were not determined for C. rotundicauda due to lack of data. These data establish a baseline for density and growth allometry of juvenile T. tridentatus and C. rotundicauda horseshoe crabs in Asian waters and will support future monitoring and assessment of juvenile populations and habitat resources.

  • digestible dietary protein and energy requirements of juvenile asian horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda
    Aquaculture Research, 2014
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    A 84-day feeding experiment of two juvenile horseshoe crab species, including nine formulated diets with three digestible protein (DP) levels (36%, 40% and 44%) and three digestible energy (DE) levels (14, 16 and 18 kJ g−1) versus the control, fed on frozen brine shrimp (Artemia salina), was conducted. The results showed that the survival rate of Tachypleus tridentatus ranged from 67% to 100%, while that of Carcinoscorpius rotundicauda varied from 44% to 100%. The results also indicated that the formulated diet containing 40% DP with 14 kJ g−1 DE was the best, in terms of growth and feed utilization, for the two juvenile horseshoe crab species. Final body weight (FBW), thermal-unit growth coefficient (TGC), feed efficiency (FE), nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) of T. tridentatus fed 40% DP and 14 kJ g−1 DE were significantly higher than that of T. tridentatus fed the control diet. However, for C. rotundicauda, only significantly higher FE, NRE and ERE were found in juveniles fed 40% DP and 14 kJ g−1 DE than the control diet. The present findings revealed that the optimum DP/DE ratio for the two species was 28 g protein MJ−1.

S G Cheung - One of the best experts on this subject based on the ideXlab platform.

  • fatty acids from controlled feeding as dietary markers of juvenile chinese horseshoe crab Tachypleus tridentatus
    Journal of the Marine Biological Association of the United Kingdom, 2019
    Co-Authors: Billy K Y Kwan, Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    The potential use of fatty acid (FA) profile as a dietary tracer in juvenile Chinese horseshoe crab Tachypleus tridentatus was assessed in a feeding experiment. Selected feed was provided to the juveniles at various growth stages according to their food sources in the wild: larval and adult brine shrimp Artemia salina for the first six months, followed by a mixture of short-neck clam Ruditapes philippinarum and greasyback shrimp Metapenaeus ensis for a further six months. Juvenile horseshoe crab haemolymph and tissues of book gill, opisthosomal spine, chelicera and swimming leg were sampled after the feeding experiment. The FA profiles revealed that the juvenile haemolymph and various tissues had a total of 23–24 FA components. The major FA components consisted of saturated (palmitic and stearic) at 22–34%, monosaturated (oleic) at 7–34% and polyunsaturated (eicosapentaenoic and arachidonic) FAs at 9–27%. According to principal component analysis, the FA signatures of juvenile haemolymph were greatly influenced by the shift of food sources from brine shrimp to clam and shrimp meat, whereas the FA profiles of different tissues were more resistant to the nutrient alteration. The present findings confirmed that the FA profile of both juvenile haemolymph and different tissues reflected the FA composition of recent and previous diets, respectively; and thus may be useful in indicating the foraging information of juvenile horseshoe crabs in the field.

  • responses of growth and hemolymph quality in juvenile chinese horseshoe crab Tachypleus tridentatus xiphosura to sublethal tributyltin and cadmium
    Ecotoxicology, 2015
    Co-Authors: Billy K Y Kwan, S G Cheung, Alice K Y Chan, Paul K S Shin
    Abstract:

    Responses of growth endpoints and hemolymph constituents in juvenile Chinese horseshoe crab Tachypleus tridentatus under treatments of 0.01 and 0.1 mg/l tributyltin (TBT) and 0.1 and 1 mg/l cadmium (Cd) were examined in a 12-week experiment. A significant decline in final body weight, final prosomal width, percentage of individuals molted and mean molting time was detected under TBT exposures. While morphological abnormalities of the juveniles between TBT treatments and the control were statistically indistinguishable, significantly higher occurrences of carapace erosion and appendage loss were noted under 0.1 and 1 mg/l Cd exposures. Various hemolymph quality indicators, including hemolymph plasma protein level, amebocyte viability and percentage of granular-spherical state of amebocytes of the juveniles exposed to TBT or Cd were significantly lower than the control. Such a decrease in hemolymph quality suggested deleterious effects of metal contaminant-induced stressors on the health status of the juveniles even at low exposure levels (i.e., 0.01 mg/l TBT and 0.1 mg/l Cd). Changes of hemolymph parameters in juvenile horseshoe crabs were more sensitive than growth performance as well as morphological abnormalities in response to metal stressors, and can be used as an indicator to reflect habitat conditions and contaminant levels.

  • preliminary home range study of juvenile chinese horseshoe crabs Tachypleus tridentatus xiphosura using passive tracking methods
    2015
    Co-Authors: Billy K Y Kwan, Paul K S Shin, S G Cheung
    Abstract:

    Three passive tracking methods, using colored plastic tag (CPT), passive integrated transponder (PIT) tag, and CPT plus PIT were compared to track the movements of juvenile Chinese horseshoe crabs, Tachypleus tridentatus, in summer 2013 on a mudflat in Hong Kong. The study site was re-visited within 2 months after the release of the tagged individuals on ten occasions during low tides. The cumulative recovery rates of the tagged juveniles ranged from 70 to 82 %, with the number of position fixes where each individual was recovered during the repeated field visits varying from one to seven. Based on the adaptive kernel density estimation approach, the mean home range size (indicated by 95 % utilization distribution) tracked by different methods varied between 269 and 462 m2. While the effects of tracking methods on home range size of the juveniles were statistically indistinguishable, PIT tags could be used as a longer-term tracking device for juvenile horseshoe crabs because the tag injected into animal bodies did not cause noticeable effects on survival, growth and molting. Within the body size range of 7th–10th instar juveniles (prosomal width 31–59 mm) used in the present study, no significant correlation was found between body size and home range area. From the analysis of utilization distribution, the juveniles were noted to exhibit residential and nomadic movement patterns, which might be associated with the distribution of food patches on the mudflat. The restricted movements of juveniles in this study suggest potential for high susceptibility to localized habitat disturbance.

  • population structure and growth of juvenile horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda xiphosura in southern china
    2015
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Billy K Y Kwan, Paul K S Shin
    Abstract:

    The abundance, population structure and growth of juvenile Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda are rarely reported in the literature. This study investigated the density and growth allometry of these sympatric species on the intertidal areas of three spawning and nursery beaches, Xi Bei Ling (XBL), Jin Hai Wan (JHW) and Xi Chang (XC) along the coast of Beibu Gulf, southern China. While T. tridentatus and C. rotundicauda coexisted on JHW and XC beaches, only T. tridentatus was found at XBL. The density of T. tridentatus (0.9–3.2 individuals/100 m2) was significantly higher than that of C. rotundicauda (0.1–1.7 individuals/100 m2) at JHW, but densities were similar at XC. Juvenile T. tridentatus ranged in size (prosomal width) from 14 to 89 mm and were estimated to represent instars 4–12 and ages 2–8 years based on previous studies. C. rotundicauda juveniles were 16–75 mm in prosomal width and represented instars 5–15. The Hiatt growth model on the relationship between pre- and post-molt size data showed similar growth increments in juvenile T. tridentatus and C. rotundicauda. Growth rates for T. tridentatus varied from 4.4 to 19.7 mm/year, depending on instar stage and site. Growth rates were not determined for C. rotundicauda due to lack of data. These data establish a baseline for density and growth allometry of juvenile T. tridentatus and C. rotundicauda horseshoe crabs in Asian waters and will support future monitoring and assessment of juvenile populations and habitat resources.

  • digestible dietary protein and energy requirements of juvenile asian horseshoe crabs Tachypleus tridentatus and carcinoscorpius rotundicauda
    Aquaculture Research, 2014
    Co-Authors: Menghong Hu, Youji Wang, S G Cheung, Paul K S Shin
    Abstract:

    A 84-day feeding experiment of two juvenile horseshoe crab species, including nine formulated diets with three digestible protein (DP) levels (36%, 40% and 44%) and three digestible energy (DE) levels (14, 16 and 18 kJ g−1) versus the control, fed on frozen brine shrimp (Artemia salina), was conducted. The results showed that the survival rate of Tachypleus tridentatus ranged from 67% to 100%, while that of Carcinoscorpius rotundicauda varied from 44% to 100%. The results also indicated that the formulated diet containing 40% DP with 14 kJ g−1 DE was the best, in terms of growth and feed utilization, for the two juvenile horseshoe crab species. Final body weight (FBW), thermal-unit growth coefficient (TGC), feed efficiency (FE), nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) of T. tridentatus fed 40% DP and 14 kJ g−1 DE were significantly higher than that of T. tridentatus fed the control diet. However, for C. rotundicauda, only significantly higher FE, NRE and ERE were found in juveniles fed 40% DP and 14 kJ g−1 DE than the control diet. The present findings revealed that the optimum DP/DE ratio for the two species was 28 g protein MJ−1.

Nurlisa A. Butet - One of the best experts on this subject based on the ideXlab platform.

  • KEPASTIAN TAKSONOMI DAN SEBARAN BELANGKAS Tachypleus tridentatus Leach 1819 DI PERAIRAN BALIKPAPAN TIMUR
    Jurnal Ilmu dan Teknologi Kelautan Tropis, 2018
    Co-Authors: Erwyansyah, Yusli Wardiatno, Rahmat Kurnia, Nurlisa A. Butet
    Abstract:

    ABSTRAK Belangkas Tachypleus tridentatus adalah salah satu hewan bentik laut yang menghuni perairan pesisir Balikpapan Timur. Informasi tentang populasi belangkas di lokasi masih terbatas, dan IUCN secara luas mengklasifikasikannya dalam kategori data deficient . Penelitian ini bertujuan untuk menjelaskan kepastian taksonomi secara genetik dan sebaran T. tridentatus di perairan pesisir Balikpapan Timur. Belangkas diperoleh menggunakan alat tangkap nelayan setempat (dogol - sejenis pukat dan jaring insang) di daerah Teritip dan Manggar, masing-masing pada jarak sekitar 1 dan 2 mil dari garis pantai. Pengambilan belangkas dilakukan mulai Januari hingga Maret 2018 pada fase bulan berbeda. Belangkas yang tertangkap dihitung dan dicatat lokasi penangkapannya serta diamati karakter morfologinya untuk analisis sebaran dan sebagian belangkas diambil darahnya untuk analisis kepastian taksonomi dengan menggunakan penanda gen CO1. Karakter morfologi utama berupa telson yang berbentuk segitiga dan duri kecil yang banyak terdapat pada ophisthosoma, secara genetis menunjukkan bahwa jenis yang dikumpulkan adalah T. tridentatus . Sebagian besar belangkas yang ditemukan di lokasi penelitian adalah belangkas dewasa yang menyebar secara acak, dengan lebar prosoma berkisar antara 22,5 hingga 30,5 cm untuk jantan dan 28,5 hingga 37,5 cm untuk betina. Jumlah belangkas terbanyak ditemukan di daerah Teritip dan berdasarkan fase bulan terjadi pada kuarter ketiga. Penelitian ini menguatkan kepastian adanya jenis T. tridentatus di lokasi penelitian dengan ciri yang mudah dikenali serta konektivitas pergerakan T. tridentatus ke lokasi lain di sekitar perairan Balikpapan Timur. ABSTRACT The tri-spine horseshoe crab Tachypleus tridentatus is one of marine benthic animals inhabiting East Balikpapan coastal waters. Information on horseshoe crab population in the location is still limited and IUCN broadly classifies the crab in deficient data category. This study was aimed at elucidating t he taxonomic certainty genetically and distribution of T . tridentatus in coastal waters of East Balikpapan. The crabs were collected by local gear of fisherman (dogol – a trawl like fishing-gear and gill net) in the Teritip and Manggar areas, each at a distance of 1 and 2 miles from coastline. Collecting takes place between January to March 2018 at different moon phases, location, number and morphological characters of the crabs was recorded and blood was taken from some individuals. Primary morphological characters in the form of triangular shape of telson and abundant tiny spines on ophisthosoma, genetically ascertained that the collected crab is T . tridentatus . Most of these crabs found was adult and randomly dispersed; with the width of prosoma ranged from 22.5 to 30.5 cm for males and 28.5 to 37.5 cm for females. The highest number of crab was found in the Teritip area and in the third quarter moon phase. This study reinforce the certainty of T. tridentatus in the study site with easily recognized morphological characters and the connectivity with other sites around Eastern Balikpapan waters.

  • kepastian taksonomi dan sebaran belangkas Tachypleus tridentatus leach 1819 di perairan balikpapan timur
    Jurnal Ilmu dan Teknologi Kelautan Tropis, 2018
    Co-Authors: Yusli Wardiatno, Rahmat Kurnia, Nurlisa A. Butet
    Abstract:

    Belangkas Tachypleus tridentatus adalah salah satu hewan bentik laut yang menghuni perairan pesisir Balikpapan Timur. Informasi tentang populasi belangkas di lokasi masih terbatas, dan IUCN secara luas mengklasifikasikannya dalam kategori data deficient. Penelitian ini bertujuan untuk menjelaskan kepastian taksonomi secara genetik dan sebaran T. tridentatus di perairan pesisir Balikpapan Timur. Belangkas diperoleh menggunakan alat tangkap nelayan setempat (dogol - sejenis pukat dan jaring insang) di daerah Teritip dan Manggar, masing-masing pada jarak sekitar 1 dan 2 mil dari garis pantai. Pengambilan belangkas dilakukan mulai Januari hingga Maret 2018 pada fase bulan berbeda. Belangkas yang tertangkap dihitung dan dicatat lokasi penangkapannya serta diamati karakter morfologinya untuk analisis sebaran dan sebagian belangkas diambil darahnya untuk analisis kepastian taksonomi dengan menggunakan penanda gen CO1. Karakter morfologi utama berupa telson yang berbentuk segitiga dan duri kecil yang banyak terdapat pada ophisthosoma, secara genetis menunjukkan bahwa jenis yang dikumpulkan adalah T. tridentatus. Sebagian besar belangkas yang ditemukan di lokasi penelitian adalah belangkas dewasa yang menyebar secara acak, dengan lebar prosoma berkisar antara 22,5 hingga 30,5 cm untuk jantan dan 28,5 hingga 37,5 cm untuk betina. Jumlah belangkas terbanyak ditemukan di daerah Teritip dan berdasarkan fase bulan terjadi pada kuarter ketiga. Penelitian ini menguatkan kepastian adanya jenis T. tridentatus di lokasi penelitian dengan ciri yang mudah dikenali serta konektivitas pergerakan T. tridentatus ke lokasi lain di sekitar perairan Balikpapan Timur.