2020 Vol. 42, No. 6
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2020, 42(6): 1-8.
doi: 10.3969/j.issn.0253-4193.2020.06.001
Abstract:
Currently, the global nitrogen and phosphorus cycles are out of balance due to anthropogenic activities which produce a large amount of reactive nitrogen and phosphorus annually. The incremental N and P are mainly derived from production and application of synthetic N fertilizers, manure application, large areas of cultivated leguminous crops that could fix atmospheric N2, and NOx emitted from fossil fuel combustion. It should be noted that crop and livestock production systems are the major cause of human alteration of the global N and P cycles. Increased human sewage and fertilizer application in agricultural production have significantly raised the inputs of N and P nutrients to coastal ecosystems leading to a global spread of eutrophication. Most of these inputs are transported to the coastal ocean via river runoff and atmospheric deposition. More than half of the incremental N and P loads are related to anthropogenic sources. The Baltic Sea and East China Sea present typical eutrophication condition in developed country and developing country respectively. The mitigation strategies should focus on dual nutrient strategy for successful N and P reduction, including reduction of leaching and runoff from agricultural fields, growing perennial crops, effective application of fertilizers, and planting winter cover crops.
Currently, the global nitrogen and phosphorus cycles are out of balance due to anthropogenic activities which produce a large amount of reactive nitrogen and phosphorus annually. The incremental N and P are mainly derived from production and application of synthetic N fertilizers, manure application, large areas of cultivated leguminous crops that could fix atmospheric N2, and NOx emitted from fossil fuel combustion. It should be noted that crop and livestock production systems are the major cause of human alteration of the global N and P cycles. Increased human sewage and fertilizer application in agricultural production have significantly raised the inputs of N and P nutrients to coastal ecosystems leading to a global spread of eutrophication. Most of these inputs are transported to the coastal ocean via river runoff and atmospheric deposition. More than half of the incremental N and P loads are related to anthropogenic sources. The Baltic Sea and East China Sea present typical eutrophication condition in developed country and developing country respectively. The mitigation strategies should focus on dual nutrient strategy for successful N and P reduction, including reduction of leaching and runoff from agricultural fields, growing perennial crops, effective application of fertilizers, and planting winter cover crops.
2020, 42(6): 9-19.
doi: 10.3969/j.issn.0253-4193.2020.06.002
Abstract:
In this study, 40 groupers belonging to 10 genera of the subfamily Epinephelinae from Western Pacific were collected, and partial sequences of 16S rRNA gene and COI gene were amplified and determined. The molecular phylogenetic relationships were constructed and analyzed using maximum likelihood method. The results showed that the length of COI gene was 651 bp, encoding 227 amino acids. While the consensus sequences of 16S rRNA gene were 566 bp, with certain base insertion and deletion. The sequences of 16S rRNA gene were more conserved than those of COI gene. The phylogenetic tree of the 10 genera of the subfamily Epinephelinae was constructed and the results showed that Plectropomus was first separated and rooted at the base of the tree, indicating its evolutionary status was most primitive. 6 species from Plectropomus were clustered as a monophyletic group. Aethaloperca was close to Cephalopholis, which tightly clustered together. Variola was located between Plectropomus and Cephalopholis. Epinephelus was located at the top of the tree, indicating its advanced evolutionary status. The species from Epinephelus in the tree were clustered as two parallel branches, instead of a monophyletic group; Cromileptes, Triso, Hyporthodus, Anyperodon and Promicrops could not form an independent branch but cluster together with species from Epinephelus, indicating their close relationship within Epinephelus and some species might belong to Epinephelus.
In this study, 40 groupers belonging to 10 genera of the subfamily Epinephelinae from Western Pacific were collected, and partial sequences of 16S rRNA gene and COI gene were amplified and determined. The molecular phylogenetic relationships were constructed and analyzed using maximum likelihood method. The results showed that the length of COI gene was 651 bp, encoding 227 amino acids. While the consensus sequences of 16S rRNA gene were 566 bp, with certain base insertion and deletion. The sequences of 16S rRNA gene were more conserved than those of COI gene. The phylogenetic tree of the 10 genera of the subfamily Epinephelinae was constructed and the results showed that Plectropomus was first separated and rooted at the base of the tree, indicating its evolutionary status was most primitive. 6 species from Plectropomus were clustered as a monophyletic group. Aethaloperca was close to Cephalopholis, which tightly clustered together. Variola was located between Plectropomus and Cephalopholis. Epinephelus was located at the top of the tree, indicating its advanced evolutionary status. The species from Epinephelus in the tree were clustered as two parallel branches, instead of a monophyletic group; Cromileptes, Triso, Hyporthodus, Anyperodon and Promicrops could not form an independent branch but cluster together with species from Epinephelus, indicating their close relationship within Epinephelus and some species might belong to Epinephelus.
2020, 42(6): 20-28.
doi: 10.3969/j.issn.0253-4193.2020.06.003
Abstract:
Based on the bottom trawl surveys in the Haizhou Bay and adjacent waters during spring and autumn of 2011 and 2013−2018, the performance of regular GAM and PCA-GAM was compared, and the distribution of Cynoglossus joyneri in this area was predicted. The predictive ability and fitting effect of the two GAMs were evaluated by cross-validation. The results showed that the goodness of fit and prediction effects of PCA-GAM were better than those of regular GAM. In spring and autumn, the abundance of C. joyneri in the southern waters was higher than that in the northern waters, and the abundance in the near-shore shallow waters was larger than that in the deep waters. The higher water temperature in the coastal waters of the southern Haizhou Bay was conducive to the development of gonads for the spawning groups during spring and autumn. The lower salinity was conducive to the growth and development of fish eggs and larvae. At the same time, the abundant prey resources in the coastal waters provides a large amount of food for it after spawning period. In this study, two GAMs were used to predict the resource distribution of C. joyneri in the Haizhou Bay in spring and autumn of 2018. The results showed that the predicted abundance by PCA-GAM were more consistent with the actual catches, and the performance of PCA-GAM was better than the regular GAM. This study provides a new method for studying the spatial distribution of marine organisms in the future.
Based on the bottom trawl surveys in the Haizhou Bay and adjacent waters during spring and autumn of 2011 and 2013−2018, the performance of regular GAM and PCA-GAM was compared, and the distribution of Cynoglossus joyneri in this area was predicted. The predictive ability and fitting effect of the two GAMs were evaluated by cross-validation. The results showed that the goodness of fit and prediction effects of PCA-GAM were better than those of regular GAM. In spring and autumn, the abundance of C. joyneri in the southern waters was higher than that in the northern waters, and the abundance in the near-shore shallow waters was larger than that in the deep waters. The higher water temperature in the coastal waters of the southern Haizhou Bay was conducive to the development of gonads for the spawning groups during spring and autumn. The lower salinity was conducive to the growth and development of fish eggs and larvae. At the same time, the abundant prey resources in the coastal waters provides a large amount of food for it after spawning period. In this study, two GAMs were used to predict the resource distribution of C. joyneri in the Haizhou Bay in spring and autumn of 2018. The results showed that the predicted abundance by PCA-GAM were more consistent with the actual catches, and the performance of PCA-GAM was better than the regular GAM. This study provides a new method for studying the spatial distribution of marine organisms in the future.
2020, 42(6): 29-35.
doi: 10.3969/j.issn.0253-4193.2020.06.004
Abstract:
Illex argentinus was a short life cycle species. Its resource abundance is susceptible to changes in the marine environment, especially in its early life history stage. According to the production statistics of the Chinese squid jigging fleet during 2003−2016 in the Southwest Atlantic and the sea surface temperature (SST) of the spawning ground from satellite remote sensing, the correlation analysis method was used to select the featured area representing SST changes during the spawning season (June) of I. argentinus. Based on the assumption that the ratio of optimum SST range to the total area (Ps) of the spawning ground of I. argentinus is positively correlated with the abundance index (catch per fishing unit, CPUE, t/ship), the optimum spawning area and suitable sea water temperature range of I. argentinus were traced back, and a variety of multivariate linear prediction models of abundance index based on the environmental factors were established. The correlation analysis shows that there are significant correlations between SST and CPUE in two consecutive sea areas (Area 1, Area 2) in June. They are 42.5°−44°S, 57.5°−59°W (Area 1) and 39°−39.5°S, 45°−46°W (Area 2) respectively. The inferred spawning area of I. argentinus ranges from 37.5°S to 44°S and 41.5°W to 51.5°W, and the optimum SST in the spawning area is 16°C to 17.5°C. The SSTs of two featured areas (Area 1, Area 2) and Ps in the inferred spawning area are used to establish four types of multivariate linear prediction models of abundance index (ICPUE), the results show that the fourth model containing the featured areas and Ps in the inferred spawning area is superior to the other 3 models, and its prediction model of abundance index is ICPUE=1.390 4×Ps+0.261 9×SSTArea 1+0.096 2×SSTArea 2−3.248 0.
Illex argentinus was a short life cycle species. Its resource abundance is susceptible to changes in the marine environment, especially in its early life history stage. According to the production statistics of the Chinese squid jigging fleet during 2003−2016 in the Southwest Atlantic and the sea surface temperature (SST) of the spawning ground from satellite remote sensing, the correlation analysis method was used to select the featured area representing SST changes during the spawning season (June) of I. argentinus. Based on the assumption that the ratio of optimum SST range to the total area (Ps) of the spawning ground of I. argentinus is positively correlated with the abundance index (catch per fishing unit, CPUE, t/ship), the optimum spawning area and suitable sea water temperature range of I. argentinus were traced back, and a variety of multivariate linear prediction models of abundance index based on the environmental factors were established. The correlation analysis shows that there are significant correlations between SST and CPUE in two consecutive sea areas (Area 1, Area 2) in June. They are 42.5°−44°S, 57.5°−59°W (Area 1) and 39°−39.5°S, 45°−46°W (Area 2) respectively. The inferred spawning area of I. argentinus ranges from 37.5°S to 44°S and 41.5°W to 51.5°W, and the optimum SST in the spawning area is 16°C to 17.5°C. The SSTs of two featured areas (Area 1, Area 2) and Ps in the inferred spawning area are used to establish four types of multivariate linear prediction models of abundance index (ICPUE), the results show that the fourth model containing the featured areas and Ps in the inferred spawning area is superior to the other 3 models, and its prediction model of abundance index is ICPUE=1.390 4×Ps+0.261 9×SSTArea 1+0.096 2×SSTArea 2−3.248 0.
Decadal variations in habitat suitability of Dosidicus gigas in the Southeast Pacific Ocean off Peru
2020, 42(6): 36-43.
doi: 10.3969/j.issn.0253-4193.2020.06.005
Abstract:
Dosidicus gigas is an important fishing target by Chinese squid-jigging fisheries, which is widely distributed in the Southeast Pacific Ocean. Its population is largely affected by climatic and environmental conditions on the fishing ground. In this study, we calculated the habitat suitability index (HSI) on the fishing ground of D. gigas in the Southeast Pacific Ocean off Peru from January to December during 1950 to 2015 based on sea surface temperature (SST) and the anomalies of sea surface height (SSHA), and variability in the environmental variables and habitat quality were further analyzed under the warm and cold phases of the Pacific Decadal Oscillation (PDO). The results suggested that PDO showed cold, warm and cold phases from 1950 to 2015. The anomalies of SST (SSTA) and SSHA during the cold PDO were significantly lower than those during the warm PDO. The cross correlation analysis suggested that both the SSTA and the SSHA were significantly positively correlated with the PDO index. However, and the HSI values on the fishing ground of D. gigas were significantly negatively correlated with the PDO index, SSTA and SSHA. During the cold PDO, the water temperature became cold, and the SSH decreased, these changes led to enlarged areas of suitable SST and SSHA for D. gigas, therefore, the favorable habitats largely increased. However, during the warm PDO, the water temperature became warm, the SSH elevated, whereas the ranges of suitable SST and SSHA contracted, all these changes resulted in the decrease of the suitable habitat of D. gigas. Our findings suggested that PDO regulated the environmental conditions on the fishing ground of D. gigas off Peru, and further significantly affected the habitat quality and suitable ranges of the habitat.
Dosidicus gigas is an important fishing target by Chinese squid-jigging fisheries, which is widely distributed in the Southeast Pacific Ocean. Its population is largely affected by climatic and environmental conditions on the fishing ground. In this study, we calculated the habitat suitability index (HSI) on the fishing ground of D. gigas in the Southeast Pacific Ocean off Peru from January to December during 1950 to 2015 based on sea surface temperature (SST) and the anomalies of sea surface height (SSHA), and variability in the environmental variables and habitat quality were further analyzed under the warm and cold phases of the Pacific Decadal Oscillation (PDO). The results suggested that PDO showed cold, warm and cold phases from 1950 to 2015. The anomalies of SST (SSTA) and SSHA during the cold PDO were significantly lower than those during the warm PDO. The cross correlation analysis suggested that both the SSTA and the SSHA were significantly positively correlated with the PDO index. However, and the HSI values on the fishing ground of D. gigas were significantly negatively correlated with the PDO index, SSTA and SSHA. During the cold PDO, the water temperature became cold, and the SSH decreased, these changes led to enlarged areas of suitable SST and SSHA for D. gigas, therefore, the favorable habitats largely increased. However, during the warm PDO, the water temperature became warm, the SSH elevated, whereas the ranges of suitable SST and SSHA contracted, all these changes resulted in the decrease of the suitable habitat of D. gigas. Our findings suggested that PDO regulated the environmental conditions on the fishing ground of D. gigas off Peru, and further significantly affected the habitat quality and suitable ranges of the habitat.
2020, 42(6): 44-51.
doi: 10.3969/j.issn.0253-4193.2020.06.006
Abstract:
According to the demersal trawling survey data in the Haizhou Bay and its adjacent waters in autumn of 2011 and 2013−2018, we studied the habitat suitability of Saurida elongata, using biotic and abiotic factors data, such as bottom water temperature, bottom salinity, water depth, resource density, bait biology, collected synchronously. The weight of each environmental factor was determined by using the model of boost regression tree (BRT), and the habitat suitability index (HSI) model was established by using arithmetic mean method and geometry mean method respectively, and the optimal model was determined by cross validation. The results show that the most suitable bottom water temperature range for the Saurida elongata to inhabit in fall was 17.5−18℃, the most suitable bottom salinity range was 31.3−32, and the most suitable water depth range was 24−37 m. Three main bait organisms were selected as biological factors, namely, Loligo spp., Metapenaeopsis dalei and Amblychaeturichthys hexanema. The HSI model was established with the bottom water temperature, bottom salinity and water depth as the influencing factors. The results show that the feed factors contributed most significantly to the total deviation of spatial distribution, followed by the water depth and bottom water temperature. Through cross validation, it is found that the weighted HSI model with arithmetic mean method algorithm has lower Akaike Information Criterion (AIC). The results show that the most suitable habitat (HSI≥0.7) of Saurida elongata in autumn was 34.5°−36°N, 119°−121°E, among which 35°−36°N was the most suitable habitat, and the HSI increased from near shore to sea.
According to the demersal trawling survey data in the Haizhou Bay and its adjacent waters in autumn of 2011 and 2013−2018, we studied the habitat suitability of Saurida elongata, using biotic and abiotic factors data, such as bottom water temperature, bottom salinity, water depth, resource density, bait biology, collected synchronously. The weight of each environmental factor was determined by using the model of boost regression tree (BRT), and the habitat suitability index (HSI) model was established by using arithmetic mean method and geometry mean method respectively, and the optimal model was determined by cross validation. The results show that the most suitable bottom water temperature range for the Saurida elongata to inhabit in fall was 17.5−18℃, the most suitable bottom salinity range was 31.3−32, and the most suitable water depth range was 24−37 m. Three main bait organisms were selected as biological factors, namely, Loligo spp., Metapenaeopsis dalei and Amblychaeturichthys hexanema. The HSI model was established with the bottom water temperature, bottom salinity and water depth as the influencing factors. The results show that the feed factors contributed most significantly to the total deviation of spatial distribution, followed by the water depth and bottom water temperature. Through cross validation, it is found that the weighted HSI model with arithmetic mean method algorithm has lower Akaike Information Criterion (AIC). The results show that the most suitable habitat (HSI≥0.7) of Saurida elongata in autumn was 34.5°−36°N, 119°−121°E, among which 35°−36°N was the most suitable habitat, and the HSI increased from near shore to sea.
2020, 42(6): 52-61.
doi: 10.3969/j.issn.0253-4193.2020.06.007
Abstract:
Based on the macrobenthos materials samples collected in August 2009, October 2009, May 2010 and August 2010 in the Laizhou Bay, the present study analyzed species composition, abundance, biomass, community structure and compared with historical data of macrobenthos. The results suggested that 272 species of macrobenthos were identified in the research region, including 122 species of Polychaetea, 64 of Crustacea, 46 of Mullusca, 18 of Echinodermata, 9 of Pisces and 13 of other groups. The total average abundance was (1102.56±216.32) ind./m2, average biomass was (28.16±8.45) g/m2, Polychaetes were the most dominant groups in the abundance and Mollusks were dominant in the biomass. Regarding the spatial influence on macrobenthos, low values of abundance and biomass usually appeared in stations outside of the Huanghe River Estuary in the west of the bay, but high values occurred in the central of Bohai Sea. Regarding the temporal influence on macrobenthos, significant seasonal variations in the abundance and biomass were observed. The dominant species were distinct, the relative important species were Sternaspis sculata, Glycinde gurjanovae and Alvenius ojianus. Compared with the historical data, the species composition and dominant species had showed an obvious miniaturization trend.
Based on the macrobenthos materials samples collected in August 2009, October 2009, May 2010 and August 2010 in the Laizhou Bay, the present study analyzed species composition, abundance, biomass, community structure and compared with historical data of macrobenthos. The results suggested that 272 species of macrobenthos were identified in the research region, including 122 species of Polychaetea, 64 of Crustacea, 46 of Mullusca, 18 of Echinodermata, 9 of Pisces and 13 of other groups. The total average abundance was (1102.56±216.32) ind./m2, average biomass was (28.16±8.45) g/m2, Polychaetes were the most dominant groups in the abundance and Mollusks were dominant in the biomass. Regarding the spatial influence on macrobenthos, low values of abundance and biomass usually appeared in stations outside of the Huanghe River Estuary in the west of the bay, but high values occurred in the central of Bohai Sea. Regarding the temporal influence on macrobenthos, significant seasonal variations in the abundance and biomass were observed. The dominant species were distinct, the relative important species were Sternaspis sculata, Glycinde gurjanovae and Alvenius ojianus. Compared with the historical data, the species composition and dominant species had showed an obvious miniaturization trend.
2020, 42(6): 62-69.
doi: 10.3969/j.issn.0253-4193.2020.06.008
Abstract:
Coral reef is one of the most diverse ecosystem in the ocean, and benthic shellfish is an important component of this ecosystem. We used the SCUBA diving line intercept transect quantitative method to investigate the community status and characteristics of benthic shellfish in the coral reef area of Weizhou Island, Beibu Gulf, covered 6 sites. Sectional benthic shellfish were qualitatively and quantitatively collected in the fall (October 2015) and spring (May 2018). The species composition, abundance, biodiversity index and so on were analyzed. Based on the two survey results, 128 species of benthic shellfish were found in the coral reefs of Weizhou Island, belonging to 1 family, 1 genera, 3 species of Polyplacophora, and 25 families, 46 generas, 68 species of Gastropoda, and 22 families, 31 generas, 57 species of Bivalvia. Dominant species are Parahyotissa numisma, Beguina semiorbiculata, Thais echinata, Trochus maculatus, Euplica versicolor, Barbatia obliquata, Atrina verxillum, Cantharus cecillei, Cerithium dialeucum, Drupa margariticola. We recorded 2 class, 14 family, 43 species in quantitative transects in spring of 2018 and the total species, biomass, Shannon-Wiener index, Margalef index and Pielou index are 3.39 ind./m2, 86.94 g/m2, 3.31, 3.50 and 0.37. By comparing and analyzing the ecological indices of benthic shellfish in different years, the shellfish biomes in the coral reefs showed good succession development during 2015 to 2018. The shellfish community in the coral reef area of the South China Sea may be affected by both the intensity of anthropogenic disturbance and latitude. This study provided valueable data to rationally develop and utilize marine biological resources, biological protection and ecological restoration for the coral reef ecosystem in the Weizhou Island.
Coral reef is one of the most diverse ecosystem in the ocean, and benthic shellfish is an important component of this ecosystem. We used the SCUBA diving line intercept transect quantitative method to investigate the community status and characteristics of benthic shellfish in the coral reef area of Weizhou Island, Beibu Gulf, covered 6 sites. Sectional benthic shellfish were qualitatively and quantitatively collected in the fall (October 2015) and spring (May 2018). The species composition, abundance, biodiversity index and so on were analyzed. Based on the two survey results, 128 species of benthic shellfish were found in the coral reefs of Weizhou Island, belonging to 1 family, 1 genera, 3 species of Polyplacophora, and 25 families, 46 generas, 68 species of Gastropoda, and 22 families, 31 generas, 57 species of Bivalvia. Dominant species are Parahyotissa numisma, Beguina semiorbiculata, Thais echinata, Trochus maculatus, Euplica versicolor, Barbatia obliquata, Atrina verxillum, Cantharus cecillei, Cerithium dialeucum, Drupa margariticola. We recorded 2 class, 14 family, 43 species in quantitative transects in spring of 2018 and the total species, biomass, Shannon-Wiener index, Margalef index and Pielou index are 3.39 ind./m2, 86.94 g/m2, 3.31, 3.50 and 0.37. By comparing and analyzing the ecological indices of benthic shellfish in different years, the shellfish biomes in the coral reefs showed good succession development during 2015 to 2018. The shellfish community in the coral reef area of the South China Sea may be affected by both the intensity of anthropogenic disturbance and latitude. This study provided valueable data to rationally develop and utilize marine biological resources, biological protection and ecological restoration for the coral reef ecosystem in the Weizhou Island.
2020, 42(6): 70-82.
doi: 10.3969/j.issn.0253-4193.2020.06.009
Abstract:
To better understand the ecological characteristics of the macro-fouling community in the northeastern waters of Pingtan Island, East China Sea, a study was conducted by test panels from June 2017 to May 2018. A total of 92 species of fouling organisms belonging to 13 phyla were recorded. The community composition was dominated by coastal warm-water species, and the main dominant species were sessile Amphibalanus reticulatus, Biflustra grandicella, Balanus trigonus, Ectopleura crocea, and motile Jassa falcata, and Maeropsis serratipalma. Bioattachment occurred throughout the year, the main period of settlement extended from June to August (the biomass ranged from 7 326.0 g/m2 to 12 970.0 g/m2), and the off-seasons of settlement extended from December to February of next year (the biomass ranged from 39.5 g/m2 to 1 580.5 g/m2). The main functional feeding group of macro-fouling organisms was suspension feeder. Temperature and salinity were the most important environmental factors affecting the geographical distribution of macro-fouling organisms. Water transparency, hydrodynamic conditions, surface runoff as well as human activity (such as aquaculture production) also had important impact on the settlement of macro-fouling organisms.
To better understand the ecological characteristics of the macro-fouling community in the northeastern waters of Pingtan Island, East China Sea, a study was conducted by test panels from June 2017 to May 2018. A total of 92 species of fouling organisms belonging to 13 phyla were recorded. The community composition was dominated by coastal warm-water species, and the main dominant species were sessile Amphibalanus reticulatus, Biflustra grandicella, Balanus trigonus, Ectopleura crocea, and motile Jassa falcata, and Maeropsis serratipalma. Bioattachment occurred throughout the year, the main period of settlement extended from June to August (the biomass ranged from 7 326.0 g/m2 to 12 970.0 g/m2), and the off-seasons of settlement extended from December to February of next year (the biomass ranged from 39.5 g/m2 to 1 580.5 g/m2). The main functional feeding group of macro-fouling organisms was suspension feeder. Temperature and salinity were the most important environmental factors affecting the geographical distribution of macro-fouling organisms. Water transparency, hydrodynamic conditions, surface runoff as well as human activity (such as aquaculture production) also had important impact on the settlement of macro-fouling organisms.
2020, 42(6): 83-89.
doi: 10.3969/j.issn.0253-4193.2020.06.010
Abstract:
To elucidate the characteristics of macro-fouling communities on discus buoys, an assessment was conducted on 4 buoys deployed in offshore waters southeast of the Zhujiang River Delta and the northeastern Beibu Gulf, respectively. The abundance and biomass of macro-fouling organisms colonizing the side of buoys were 400.00−78 296.00 ind./m2 and 659.42−62 276.00 g/m2, respectively, whereas those on the bottom were 412.00−66 585.00 ind./m2 and 1 861.60−60 784.00 g/m2. At most stations, the abundance and biomass of macro-fouling organisms on the bottom of buoys were higher than on the side. The diversity index (H′) on the bottom of buoys ranged from 2.39 to 3.06, the richness index (d) from 4.02 to 6.98 and the evenness index (J′) from 0.88 to 0.91; and those on the side of buoys were from 0.64 to 2.79, 1.10 to 4.89 and 0.58 to 0.96, respectively. Both of the H′ and the d on the bottom of buoys were higher than on the side. According to the results of Hierarchical Cluster Analysis and Non-metric Multi-Dimensional Scaling, the macro-fouling communities of buoys could be clustered into 4 groups at 30% similarity. Of them, the communities on the bottom of the buoys could be basically clustered into a group while those on the sides varied with locations. Moreover, one-way Analysis of Similarities and Similarity Percentages-Species Contributions not only indicated that the macro-fouling community structure differed significantly between the side and bottom of the offshore buoys but also highlighted that the cirripedians and cnidarians made the greatest contribution to the difference. Overall, macro-fouling organisms preferentially colonized the bottom of discus buoys rather than the side.
To elucidate the characteristics of macro-fouling communities on discus buoys, an assessment was conducted on 4 buoys deployed in offshore waters southeast of the Zhujiang River Delta and the northeastern Beibu Gulf, respectively. The abundance and biomass of macro-fouling organisms colonizing the side of buoys were 400.00−78 296.00 ind./m2 and 659.42−62 276.00 g/m2, respectively, whereas those on the bottom were 412.00−66 585.00 ind./m2 and 1 861.60−60 784.00 g/m2. At most stations, the abundance and biomass of macro-fouling organisms on the bottom of buoys were higher than on the side. The diversity index (H′) on the bottom of buoys ranged from 2.39 to 3.06, the richness index (d) from 4.02 to 6.98 and the evenness index (J′) from 0.88 to 0.91; and those on the side of buoys were from 0.64 to 2.79, 1.10 to 4.89 and 0.58 to 0.96, respectively. Both of the H′ and the d on the bottom of buoys were higher than on the side. According to the results of Hierarchical Cluster Analysis and Non-metric Multi-Dimensional Scaling, the macro-fouling communities of buoys could be clustered into 4 groups at 30% similarity. Of them, the communities on the bottom of the buoys could be basically clustered into a group while those on the sides varied with locations. Moreover, one-way Analysis of Similarities and Similarity Percentages-Species Contributions not only indicated that the macro-fouling community structure differed significantly between the side and bottom of the offshore buoys but also highlighted that the cirripedians and cnidarians made the greatest contribution to the difference. Overall, macro-fouling organisms preferentially colonized the bottom of discus buoys rather than the side.
2020, 42(6): 90-100.
doi: 10.3969/j.issn.0253-4193.2020.06.011
Abstract:
According to two years (2018−2019) spring plankton surveys in the Zhoushan coastal waters, the zooplankton community structure (species composition, abundance of dominant species) were investigated, the canonical correspondence analysis (CCA) was used to study spring interanuual difference of zooplankton community and causes of their dynamics, the mechanism of community dynamics were discussed according to our results.The results show that the study region is divided into three groups according to cluster analysis of sea surface temperature (SST) and sea surface salinity (SSS): Hangzhou Bay water masses (Area I), upwelling water masses in Zhoushan Island (Area II), and water masses in Zhoushan offshore area (Area III). Water mass groups have significant influence on the composition of zooplankton community. The main species contributing to the difference between the three water masses in spring 2018 and spring 2019 (contribution rate >10%) are Calanus sinicus. The contribution species of the same water mass in two years were: Tortanus derjugini (56.91%) and Labidocera euchaeta (12.34%) in Area I, Calanus sinicus (72.64%) and Muggiaea atlantica (13.35%) in Area II, Calanus sinicus (41.93%) and Noctiluca scintillans (22.94%) in Area III. CCA shows that the first CCA axis (CCA1) and the second CCA axis (CCA2) explained 46.14% of the accumulated variance of the dominant species of zooplankton and 97.82% of the species-environment accumulated variance in spring 2018 and spring 2019. CCA1 mainly reflects the spatial difference between the offshore water mass and the Hangzhou Bay water mass. CCA2 mainly reflects the interannual difference between the stations in 2018 and 2019. Salinity is the main factor influencing the spatial difference of zooplankton community structure in spring, while temperature and chlorophyll a concentration are the main factors controlling the interannual difference of zooplankton community structure in spring.
According to two years (2018−2019) spring plankton surveys in the Zhoushan coastal waters, the zooplankton community structure (species composition, abundance of dominant species) were investigated, the canonical correspondence analysis (CCA) was used to study spring interanuual difference of zooplankton community and causes of their dynamics, the mechanism of community dynamics were discussed according to our results.The results show that the study region is divided into three groups according to cluster analysis of sea surface temperature (SST) and sea surface salinity (SSS): Hangzhou Bay water masses (Area I), upwelling water masses in Zhoushan Island (Area II), and water masses in Zhoushan offshore area (Area III). Water mass groups have significant influence on the composition of zooplankton community. The main species contributing to the difference between the three water masses in spring 2018 and spring 2019 (contribution rate >10%) are Calanus sinicus. The contribution species of the same water mass in two years were: Tortanus derjugini (56.91%) and Labidocera euchaeta (12.34%) in Area I, Calanus sinicus (72.64%) and Muggiaea atlantica (13.35%) in Area II, Calanus sinicus (41.93%) and Noctiluca scintillans (22.94%) in Area III. CCA shows that the first CCA axis (CCA1) and the second CCA axis (CCA2) explained 46.14% of the accumulated variance of the dominant species of zooplankton and 97.82% of the species-environment accumulated variance in spring 2018 and spring 2019. CCA1 mainly reflects the spatial difference between the offshore water mass and the Hangzhou Bay water mass. CCA2 mainly reflects the interannual difference between the stations in 2018 and 2019. Salinity is the main factor influencing the spatial difference of zooplankton community structure in spring, while temperature and chlorophyll a concentration are the main factors controlling the interannual difference of zooplankton community structure in spring.
2020, 42(6): 101-109.
doi: 10.3969/j.issn.0253-4193.2020.06.012
Abstract:
Based on the data obtained from bottom trawl investigation in the Haizhou Bay and adjacent waters in 2018, a mass-balance model for the Haizhou Bay ecosystem was constructed by Ecopath with Ecosim software, consisting of 26 functional groups. Using Ecopath model, we evaluated the trophic structure, trophic impact relationship and ecosystem characters of the Haizhou Bay to provide a theoretical basis for the implementation of ecosystem-based fisheries management. The result showed that in this ecosystem trophic levels of functional groups varied from 1.00 to 4.19, and the range of fish trophic level was wide, ranging from 3.22 to 4.19. Phytoplankton and molluscs were in important nutritional positions in the ecosystem facing with the pressure from both the primary producers and predators. The evaluation of the ecosystem structure and function showed that the total primary production/total respiration (TPP/TR) was 7.096, total primary production /total biomass (TPP/B) was 56.866, the connectance index (CI) and system omnivory index (SOI) were 0.429 and 0.204, indicating that the Haizhou Bay ecosystem was in an immature, unstable state and was susceptible to external disturbances. Through the study of the Haizhou Bay and its adjacent waters ecosystem model, we analyzed the nutrient structure and phylogenetic status of the sea area, which would provide a theoretical basis for the sustainable utilization and scientific management of fishery resources in the Haizhou Bay.
Based on the data obtained from bottom trawl investigation in the Haizhou Bay and adjacent waters in 2018, a mass-balance model for the Haizhou Bay ecosystem was constructed by Ecopath with Ecosim software, consisting of 26 functional groups. Using Ecopath model, we evaluated the trophic structure, trophic impact relationship and ecosystem characters of the Haizhou Bay to provide a theoretical basis for the implementation of ecosystem-based fisheries management. The result showed that in this ecosystem trophic levels of functional groups varied from 1.00 to 4.19, and the range of fish trophic level was wide, ranging from 3.22 to 4.19. Phytoplankton and molluscs were in important nutritional positions in the ecosystem facing with the pressure from both the primary producers and predators. The evaluation of the ecosystem structure and function showed that the total primary production/total respiration (TPP/TR) was 7.096, total primary production /total biomass (TPP/B) was 56.866, the connectance index (CI) and system omnivory index (SOI) were 0.429 and 0.204, indicating that the Haizhou Bay ecosystem was in an immature, unstable state and was susceptible to external disturbances. Through the study of the Haizhou Bay and its adjacent waters ecosystem model, we analyzed the nutrient structure and phylogenetic status of the sea area, which would provide a theoretical basis for the sustainable utilization and scientific management of fishery resources in the Haizhou Bay.
2020, 42(6): 110-118.
doi: 10.3969/j.issn.0253-4193.2020.06.013
Abstract:
In this paper, the net primary productivity (NPP) of the northern islands of Miaodao Archipelago in 2005, 2010 and 2017 was estimated by using ArcGIS10.2, ENVI5.1, SPSS26 and other software based on the classic CASA model, and analyzed the spatial-temporal heterogeneity of NPP from the perspectives of season, individual of island, landscape type, terrain gradient, and then analyzed the spatial-temporal heterogeneity of the landscape pattern of the five northern islands in 2005, 2010 and 2017. The relationships between them and the reasons were discussed. The results showed that: the total NPP for the five northern islands of Miaodao Archipelago was 7 520.54 t/a in terms of carbon; the mean density of NPP was 406.07 g/(m2·a) in terms of carbon; the distribution of NPP showed a significant spatial-temporal heterogeneity; the order of the average area of each landscape type from largest to smallest was coniferous forest, broad-leaved forest, construction land, grassland, arable land; the mean density of NPP from largest to smallest was broad-leaved forest, coniferous forest, arable land, grassland, construction land; the mean density of NPP of each landscape increased first with the increase of slope and height difference, and then decreased slowly; the aspect had a great influence on the NPP of forest, and the mean density of NPP of half shady slope is the largest; the annual mean density of NPP of different terrain gradients decreased with the time; the high value of NPP appeared in the mountainous area, and the low value of NPP is mainly in the flat area; due to the natural geographical conditions and the plant growth strip, the distribution of NPP was influenced by season, geographical location and landscape type.
In this paper, the net primary productivity (NPP) of the northern islands of Miaodao Archipelago in 2005, 2010 and 2017 was estimated by using ArcGIS10.2, ENVI5.1, SPSS26 and other software based on the classic CASA model, and analyzed the spatial-temporal heterogeneity of NPP from the perspectives of season, individual of island, landscape type, terrain gradient, and then analyzed the spatial-temporal heterogeneity of the landscape pattern of the five northern islands in 2005, 2010 and 2017. The relationships between them and the reasons were discussed. The results showed that: the total NPP for the five northern islands of Miaodao Archipelago was 7 520.54 t/a in terms of carbon; the mean density of NPP was 406.07 g/(m2·a) in terms of carbon; the distribution of NPP showed a significant spatial-temporal heterogeneity; the order of the average area of each landscape type from largest to smallest was coniferous forest, broad-leaved forest, construction land, grassland, arable land; the mean density of NPP from largest to smallest was broad-leaved forest, coniferous forest, arable land, grassland, construction land; the mean density of NPP of each landscape increased first with the increase of slope and height difference, and then decreased slowly; the aspect had a great influence on the NPP of forest, and the mean density of NPP of half shady slope is the largest; the annual mean density of NPP of different terrain gradients decreased with the time; the high value of NPP appeared in the mountainous area, and the low value of NPP is mainly in the flat area; due to the natural geographical conditions and the plant growth strip, the distribution of NPP was influenced by season, geographical location and landscape type.
2020, 42(6): 119-126.
doi: 10.3969/j.issn.0253-4193.2020.06.014
Abstract:
In present study, the morphology and species identification of the Neobenedenia parasites (Isolate Batam/IB) in the cage aquaculture were studied via morphological and molecular marker methods at Batam Island, Indonesia. The isolate Batam is morphological similar with Neobenedenia girellae, and it is considered to belong to the Neobenedenia genera. 394 bp of the 28S rRNA was amplified, and its similarity with other genera was between 85.86%−99.47%. The phylogenetic tree shows that IB, Neobenedenia melleni and Neobenedenia girellae are in a same cluster, and other Benedeniinae species form their own cluster. To sum up, IB is identified as the specie of Neobenedenia girellae and we support the theory that N. melleni and N. girellae are synonyms.
In present study, the morphology and species identification of the Neobenedenia parasites (Isolate Batam/IB) in the cage aquaculture were studied via morphological and molecular marker methods at Batam Island, Indonesia. The isolate Batam is morphological similar with Neobenedenia girellae, and it is considered to belong to the Neobenedenia genera. 394 bp of the 28S rRNA was amplified, and its similarity with other genera was between 85.86%−99.47%. The phylogenetic tree shows that IB, Neobenedenia melleni and Neobenedenia girellae are in a same cluster, and other Benedeniinae species form their own cluster. To sum up, IB is identified as the specie of Neobenedenia girellae and we support the theory that N. melleni and N. girellae are synonyms.
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