Tingting Han, Rongjun Shi, Zhanhui Qi, Honghui Huang, X. Gong
In this study, the variations of the seawater carbonate system parameters and air−sea CO2 flux (FCO2) of Shen’ao Bay, a typical subtropical aquaculture bay located in China, were investigated in spring 2016 (March to May). Parameters related to the seawater carbonate system and FCO2 were measured monthly in 3 different aquaculture areas (fish, oyster and seaweed) and in a non-culture area near the bay mouth. The results showed that the seawater carbonate system was markedly influenced by the biological processes of the culture species. Total alkalinity was significantly lower in the oyster area compared with the fish and seaweed areas, mainly because of the calcification process of oysters. Dissolved inorganic carbon (DIC) and CO2 partial pressure (pCO2) were highest in the fish area, followed by the oyster and non-culture areas, and lowest in the seaweed area. Oysters and fish can have indirect influences on DIC and pCO2by releasing nutrients, which facilitate the growth of seaweed and phytoplankton and therefore promote photosynthetic CO2 fixation. For these reasons, Shen’ao Bay acts as a potential CO2 sink in spring, with an average FCO2 ranging from −1.2 to −4.8 mmol m −2 d−1. CO2 fixation in the seaweed area was the largest contributor to CO2 flux, accounting for ca. 58% of the total CO2 sink capacity of the entire bay. These results suggest that the carbonate system and FCO2 of Shen’ao Bay were significantly affected by large-scale mariculture activities. A higher CO2 sink capacity could be acquired by extending the culture area of seaweed.
本研究以2016年春季(3 - 5月)中国典型的亚热带水产养殖海湾神澳湾为研究区域，对其海水碳酸盐系统参数和海气CO2通量(FCO2)的变化进行了研究。在3个不同的养殖区域(鱼、牡蛎和海藻)和海湾口附近的非养殖区域每月测量海水碳酸盐系统和FCO2相关参数。结果表明，海水碳酸盐系统受培养种生物过程的影响显著。牡蛎区总碱度明显低于鱼类和海藻区，主要原因是牡蛎的钙化过程。溶解无机碳(DIC)和CO2分压(pCO2)在鱼类区最高，牡蛎区次之，非养殖区次之，海藻区最低。牡蛎和鱼类可以通过释放营养物质间接影响DIC和pco2，这些营养物质促进海藻和浮游植物的生长，从而促进光合作用CO2的固定。由于这些原因，神鳌湾在春季作为一个潜在的CO2汇，平均FCO2在- 1.2到- 4.8 mmol m - 2 d - 1之间。海藻区的CO2固定是CO2通量的最大贡献者，约占整个海湾总CO2汇容量的58%。这些结果表明，大规模海水养殖活动对沈坳湾的碳酸盐系统和FCO2有显著影响。通过扩大海藻的养殖面积，可以获得更高的CO2吸收能力。
{"title":"Impacts of large-scale aquaculture activities on the seawater carbonate system and air-sea CO2 flux in a subtropical mariculture bay, southern China","authors":"Tingting Han, Rongjun Shi, Zhanhui Qi, Honghui Huang, X. Gong","doi":"10.3354/AEI00400","DOIUrl":"https://doi.org/10.3354/AEI00400","url":null,"abstract":"In this study, the variations of the seawater carbonate system parameters and air−sea CO2 flux (FCO2) of Shen’ao Bay, a typical subtropical aquaculture bay located in China, were investigated in spring 2016 (March to May). Parameters related to the seawater carbonate system and FCO2 were measured monthly in 3 different aquaculture areas (fish, oyster and seaweed) and in a non-culture area near the bay mouth. The results showed that the seawater carbonate system was markedly influenced by the biological processes of the culture species. Total alkalinity was significantly lower in the oyster area compared with the fish and seaweed areas, mainly because of the calcification process of oysters. Dissolved inorganic carbon (DIC) and CO2 partial pressure (pCO2) were highest in the fish area, followed by the oyster and non-culture areas, and lowest in the seaweed area. Oysters and fish can have indirect influences on DIC and pCO2by releasing nutrients, which facilitate the growth of seaweed and phytoplankton and therefore promote photosynthetic CO2 fixation. For these reasons, Shen’ao Bay acts as a potential CO2 sink in spring, with an average FCO2 ranging from −1.2 to −4.8 mmol m −2 d−1. CO2 fixation in the seaweed area was the largest contributor to CO2 flux, accounting for ca. 58% of the total CO2 sink capacity of the entire bay. These results suggest that the carbonate system and FCO2 of Shen’ao Bay were significantly affected by large-scale mariculture activities. A higher CO2 sink capacity could be acquired by extending the culture area of seaweed.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69593190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In coastal areas of China, high-density aquaculture has caused environmental problems and fish health concerns. Bacillus subtilis D9 is a new strain isolated from coastal soils which could be used in aquaculture to improve the water environment. We investigated the effect of B. subtilis D9 on the purification of coastal aquaculture wastewater and the resistance of grass carp Ctenopharyngodon idellus to pathogenic Vibrio infection. Three inoculation levels of B. subtilis D9 were used (5.5 × 107, 5.5 × 108 and 5.5×109 cfu ml-1 as BD7, BD8 and BD9, respectively), together with sterilized saline water without B. subtilis D9 as the Control. B. subtilis D9 at the inoculation level of BD8 showed the best performance with 81, 87, 91, 52 and 86% removal of NH4+-N, NO3--N, total nitrogen (TN), NO2--N and turbidity, respectively, after 25 d of treatment. These values were significantly higher than at the BD7, BD9 and Control levels. Under aeration (AIR) conditions, B. subtilis D9 at the inoculation level of BD8 showed removal efficiency of 93, 91, 95, 76 and 89%, respectively. In contrast it was only 26, 29, 16, 10 and 57% in an inactivated bacteria liquid (IBL) treatment. After 22 d of infection by Vibrio parahaemolyticus, significant differences were found in weight gain, specific growth rate and relative percentage of survival among grass carp grown on AIR, BD8 or IBL wastewater. In summary, B. subtilis D9 with aeration has beneficial effects on the purification of coastal aquaculture wastewater and on the resistance of grass carp to disease caused by V. parahaemolyticus.
{"title":"Use of Bacillus subtilis D9 to purify coastal aquaculture wastewater and improve grass carp resistance to Vibrio infection","authors":"Y. Shao, H. Zhong, L. Wang, Mma Elbashier","doi":"10.3354/aei00404","DOIUrl":"https://doi.org/10.3354/aei00404","url":null,"abstract":"In coastal areas of China, high-density aquaculture has caused environmental problems and fish health concerns. Bacillus subtilis D9 is a new strain isolated from coastal soils which could be used in aquaculture to improve the water environment. We investigated the effect of B. subtilis D9 on the purification of coastal aquaculture wastewater and the resistance of grass carp Ctenopharyngodon idellus to pathogenic Vibrio infection. Three inoculation levels of B. subtilis D9 were used (5.5 × 107, 5.5 × 108 and 5.5×109 cfu ml-1 as BD7, BD8 and BD9, respectively), together with sterilized saline water without B. subtilis D9 as the Control. B. subtilis D9 at the inoculation level of BD8 showed the best performance with 81, 87, 91, 52 and 86% removal of NH4+-N, NO3--N, total nitrogen (TN), NO2--N and turbidity, respectively, after 25 d of treatment. These values were significantly higher than at the BD7, BD9 and Control levels. Under aeration (AIR) conditions, B. subtilis D9 at the inoculation level of BD8 showed removal efficiency of 93, 91, 95, 76 and 89%, respectively. In contrast it was only 26, 29, 16, 10 and 57% in an inactivated bacteria liquid (IBL) treatment. After 22 d of infection by Vibrio parahaemolyticus, significant differences were found in weight gain, specific growth rate and relative percentage of survival among grass carp grown on AIR, BD8 or IBL wastewater. In summary, B. subtilis D9 with aeration has beneficial effects on the purification of coastal aquaculture wastewater and on the resistance of grass carp to disease caused by V. parahaemolyticus.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69593367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developing payment for ecosystem service schemes for coastal aquaculture in southwestern Taiwan","authors":"Jl Chen, YJ Hsiao, C. Chuang","doi":"10.3354/aei00422","DOIUrl":"https://doi.org/10.3354/aei00422","url":null,"abstract":"","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69594536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genetic evidence of farmed straying and introgression in Swedish wild salmon populations","authors":"S. Palm, S. Karlsson, O. Diserud","doi":"10.3354/aei00423","DOIUrl":"https://doi.org/10.3354/aei00423","url":null,"abstract":"","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69594543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shielding skirts are widely used as a non-invasive preventive measure against salmon lice Lepeophtheirus salmonis infestations on Atlantic salmon Salmo salar in sea-cages. Low levels of dissolved oxygen (DO) are reported from some sites, but not others. This disparity is usually explained by local variations in current flow and hydrography. The aim of the present study was to investigate these local variations through vertical mapping of DO and hydrography at 2 hydrographically different sites equipped with shielding skirts. The 2 sites chosen, Fornes and Soløya, are in northern Norway and are equipped with a permeable and a non-permeable skirt, respectively. Over a period of 3 d, current speed and direction were recorded outside the cage, while DO and hydrography were measured both inside and outside the cage, above and below the skirt. At Fornes, the DO inside the cage varied throughout the study period, while DO outside remained stable. The variation in DO inside the cage co-occurred with variations in strength and depth of a present pycnocline that broke down during the study period. At Soløya, DO levels were high throughout the study, and there was no gradient in salinity, temperature or density, indicating good vertical mixing. These data illustrate how the interaction between skirts and local conditions can influence the temporal and spatial variations of DO inside shielded cages and highlight the importance of studying local current conditions and hydrography when applying shielding skirts.
{"title":"Dynamics of dissolved oxygen inside salmon seacages with lice shielding skirts at two hydrographically different sites","authors":"KE Jónsdóttir, Z. Volent, J. A. Alfredsen","doi":"10.3354/aei00384","DOIUrl":"https://doi.org/10.3354/aei00384","url":null,"abstract":"Shielding skirts are widely used as a non-invasive preventive measure against salmon lice Lepeophtheirus salmonis infestations on Atlantic salmon Salmo salar in sea-cages. Low levels of dissolved oxygen (DO) are reported from some sites, but not others. This disparity is usually explained by local variations in current flow and hydrography. The aim of the present study was to investigate these local variations through vertical mapping of DO and hydrography at 2 hydrographically different sites equipped with shielding skirts. The 2 sites chosen, Fornes and Soløya, are in northern Norway and are equipped with a permeable and a non-permeable skirt, respectively. Over a period of 3 d, current speed and direction were recorded outside the cage, while DO and hydrography were measured both inside and outside the cage, above and below the skirt. At Fornes, the DO inside the cage varied throughout the study period, while DO outside remained stable. The variation in DO inside the cage co-occurred with variations in strength and depth of a present pycnocline that broke down during the study period. At Soløya, DO levels were high throughout the study, and there was no gradient in salinity, temperature or density, indicating good vertical mixing. These data illustrate how the interaction between skirts and local conditions can influence the temporal and spatial variations of DO inside shielded cages and highlight the importance of studying local current conditions and hydrography when applying shielding skirts.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43597068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Richard, F. Forget, A. Mignucci, Serge Mortreux, P. L. Gall, Callier, A. Weise, C. McKindsey, J. Bourjea
Bivalve predation by seabream has been observed worldwide and is a major concern for bivalve farmers. Farmed bivalve-seabream interactions must be better understood to ensure the sustainability of bivalve aquaculture. The objectives of this study were to characterize gilthead seabream Sparus aurata presence in a bivalve farm in Prevost Lagoon (Mediterranean Sea) using acoustic telemetry and to evaluate monthly losses of mussels Mytilus galloprovincialis and oysters Crassostrea gigas due to seabream predation over an 18 mo period inside the farm and at an unprotected experimental platform. Large (281 to 499 mm TL) seabream were more commonly detected in the bivalve farm than were small (200 to 280 mm TL) seabream. In contrast to small seabream, 90% of large seabream returned to and spent extended periods in the study area the following year, suggesting inter-annual site fidelity for large fish that used the bivalve farm as a feeding site. Signs of predation were observed on mussels and oysters throughout the year at the unprotected experimental platform. Farmers noted losses in the farm from April to September. Maximal losses (90 to 100%) were observed post-oyster ‘sticking’ and mussel socking. Despite the deployment of nets as mechanical protection to reduce predation, oyster losses represented 28% of the annual value of oysters sold while mussel losses were estimated at ca. 1%. These results suggest that bivalves must be protected by nets throughout the year to avoid predation, particularly post-handling. A collaboration between shellfish farmers and fishermen could be a sustainable solution for bivalve farming, by regularly fishing for seabream in farms, between tables and inside protective nets.
在世界范围内都观察到海鲷捕食双壳类动物的现象，这是双壳类养殖者主要关注的问题。必须更好地了解养殖双壳类与海洋生物的相互作用，以确保双壳类水产养殖的可持续性。本研究的目的是利用声波遥测技术表征Prevost泻湖(地中海)双壳类养殖场中金头海鲷(Sparus aurata)的存在，并在养殖场内和无保护的实验平台上评估18个月期间由于海鲷捕食而导致的贻贝(Mytilus galloprovincialis)和牡蛎(crasstrea gigas)的月损失。在双壳类养殖场中，大(281 ~ 499 mm TL)的海鲷比小(200 ~ 280 mm TL)的海鲷更常见。与小型海目相比，90%的大型海目在第二年返回并在研究区域停留较长时间，这表明以双壳类养殖场为觅食场所的大型鱼类的年间地点保真度。在无保护的实验平台上，贻贝和牡蛎全年都有被捕食的迹象。农民们注意到从4月到9月农场的损失。在牡蛎“粘”和贻贝“嵌套”后，观察到最大损失(90%至100%)。尽管部署了渔网作为机械保护以减少捕食，但牡蛎的损失仍占牡蛎年销售额的28%，而贻贝的损失估计约为1%。这些结果表明，双壳类动物必须全年都有网保护，以避免捕食，特别是在处理后。贝类养殖户和渔民之间的合作可能是双壳类养殖的可持续解决方案，通过定期在农场、工作台之间和防护网内捕捞海鲷。
{"title":"Farmed bivalve loss due to seabream predation in the French Mediterranean Prevost Lagoon","authors":"M. Richard, F. Forget, A. Mignucci, Serge Mortreux, P. L. Gall, Callier, A. Weise, C. McKindsey, J. Bourjea","doi":"10.3354/aei00383","DOIUrl":"https://doi.org/10.3354/aei00383","url":null,"abstract":"Bivalve predation by seabream has been observed worldwide and is a major concern for bivalve farmers. Farmed bivalve-seabream interactions must be better understood to ensure the sustainability of bivalve aquaculture. The objectives of this study were to characterize gilthead seabream Sparus aurata presence in a bivalve farm in Prevost Lagoon (Mediterranean Sea) using acoustic telemetry and to evaluate monthly losses of mussels Mytilus galloprovincialis and oysters Crassostrea gigas due to seabream predation over an 18 mo period inside the farm and at an unprotected experimental platform. Large (281 to 499 mm TL) seabream were more commonly detected in the bivalve farm than were small (200 to 280 mm TL) seabream. In contrast to small seabream, 90% of large seabream returned to and spent extended periods in the study area the following year, suggesting inter-annual site fidelity for large fish that used the bivalve farm as a feeding site. Signs of predation were observed on mussels and oysters throughout the year at the unprotected experimental platform. Farmers noted losses in the farm from April to September. Maximal losses (90 to 100%) were observed post-oyster ‘sticking’ and mussel socking. Despite the deployment of nets as mechanical protection to reduce predation, oyster losses represented 28% of the annual value of oysters sold while mussel losses were estimated at ca. 1%. These results suggest that bivalves must be protected by nets throughout the year to avoid predation, particularly post-handling. A collaboration between shellfish farmers and fishermen could be a sustainable solution for bivalve farming, by regularly fishing for seabream in farms, between tables and inside protective nets.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46119953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kelly A. Muething, F. Tomas, G. Waldbusser, B. Dumbauld
Estuaries are subject to diverse anthropogenic stressors, such as shellfish aquaculture, which involve extensive use of estuarine tidelands. Pacific oyster Crassostrea gigas aquaculture is a century-old practice in US West Coast estuaries that contributes significantly to the regional culture and economy. Native eelgrass Zostera marina also commonly occurs in intertidal areas where oyster aquaculture is practiced. Eelgrass is federally protected in the USA as ‘essential fish habitat’, restricting aquaculture activities within or near eelgrass. To contribute scientific information useful for management decisions, we sought to compare fish habitat use of oyster aquaculture and eelgrass, as well as the edges between these 2 habitats, in Willapa Bay, Washington, USA. Furthermore, given a recent shift towards off-bottom culture methods, in part to protect seagrasses, long-line and on-bottom oyster aquaculture habitats were compared. A combination of direct (underwater video, minnow traps) and indirect (predation tethering units, eelgrass surveys) methods were employed to characterize differences in fish habitat use. Eelgrass density declined within both aquaculture habitats but less so within long-line aquaculture. Most fish species in our study used long-line oyster aquaculture and eelgrass habitats similarly with minimal edge effects, and on-bottom aquaculture was used less than either of the other 2 habitat types. These results are consistent with previously observed positive relationships between fish abundance and vertical habitat structure, but also reveal species-specific behavior; larger mesopredators like Pacific staghorn sculpins were sighted more often in aquaculture than in interior eelgrass habitats.
{"title":"On the edge: assessing fish habitat use across the boundary between Pacific oyster aquaculture and eelgrass in Willapa Bay, Washington, USA","authors":"Kelly A. Muething, F. Tomas, G. Waldbusser, B. Dumbauld","doi":"10.3354/AEI00381","DOIUrl":"https://doi.org/10.3354/AEI00381","url":null,"abstract":"Estuaries are subject to diverse anthropogenic stressors, such as shellfish aquaculture, which involve extensive use of estuarine tidelands. Pacific oyster Crassostrea gigas aquaculture is a century-old practice in US West Coast estuaries that contributes significantly to the regional culture and economy. Native eelgrass Zostera marina also commonly occurs in intertidal areas where oyster aquaculture is practiced. Eelgrass is federally protected in the USA as ‘essential fish habitat’, restricting aquaculture activities within or near eelgrass. To contribute scientific information useful for management decisions, we sought to compare fish habitat use of oyster aquaculture and eelgrass, as well as the edges between these 2 habitats, in Willapa Bay, Washington, USA. Furthermore, given a recent shift towards off-bottom culture methods, in part to protect seagrasses, long-line and on-bottom oyster aquaculture habitats were compared. A combination of direct (underwater video, minnow traps) and indirect (predation tethering units, eelgrass surveys) methods were employed to characterize differences in fish habitat use. Eelgrass density declined within both aquaculture habitats but less so within long-line aquaculture. Most fish species in our study used long-line oyster aquaculture and eelgrass habitats similarly with minimal edge effects, and on-bottom aquaculture was used less than either of the other 2 habitat types. These results are consistent with previously observed positive relationships between fish abundance and vertical habitat structure, but also reveal species-specific behavior; larger mesopredators like Pacific staghorn sculpins were sighted more often in aquaculture than in interior eelgrass habitats.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"12 1","pages":"541-557"},"PeriodicalIF":2.2,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42309624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Lupo, B. L. Dutta, S. Petton, P. Ezanno, D. Tourbiez, M. Travers, F. Pernet, C. Bacher
Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to 12 mo, depending on the location in which infection was initiated. The effect of temperature was captured by the basic reproduction number (R0), which was >1 at high seawater temperatures, as opposed to values <1 at low temperatures. At the ecosystem scale, simulations showed the existence of long-distance dispersal of free-living bacteria. The western part of the bay could be reached by bacteria originating from the eastern side, though the spread time was greatly increased. Further developments of the model, including the consideration of the anthropogenic movements of oysters and oyster-specific sensitivity factors, would allow the development of accurate maps of epidemiological risks and help define aquaculture zoning.
{"title":"Spatial epidemiological modelling of infection by Vibrio aestuarianus shows that connectivity and temperature control oyster mortality","authors":"C. Lupo, B. L. Dutta, S. Petton, P. Ezanno, D. Tourbiez, M. Travers, F. Pernet, C. Bacher","doi":"10.3354/aei00379","DOIUrl":"https://doi.org/10.3354/aei00379","url":null,"abstract":"Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to 12 mo, depending on the location in which infection was initiated. The effect of temperature was captured by the basic reproduction number (R0), which was >1 at high seawater temperatures, as opposed to values <1 at low temperatures. At the ecosystem scale, simulations showed the existence of long-distance dispersal of free-living bacteria. The western part of the bay could be reached by bacteria originating from the eastern side, though the spread time was greatly increased. Further developments of the model, including the consideration of the anthropogenic movements of oysters and oyster-specific sensitivity factors, would allow the development of accurate maps of epidemiological risks and help define aquaculture zoning.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47884355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Atalah, L. Fletcher, I. Davidson, PM South, B. Forrest
The global proliferation of marine artificial habitats is rapidly altering the physical structure of coastlines, with knock-on effects on physical, chemical, and ecological processes at seascape scales. Ecological consequences of maritime sprawl associated with aquaculture are poorly understood, despite the fact that these suspended structures are particularly prone to biofouling, which can affect the industry and seascape around it. We characterised seascape-scale spatial and temporal distribution patterns of 10 biofouling taxa in relation to the presence and distance to Perna canaliculus mussel farms in New Zealand’s largest aquaculture region. Seven of 10 taxa had significantly higher cover on farms than in natural habitats throughout the region. The cover of 4 of those 7 taxa, including the high-profile pests Mytilus galloprovincialis and Undaria pinnatifida, exponentially decreased with distance from the nearest farm, while some taxa were absent from natural habitats (e.g. the ascidian Ciona robusta). In contrast, several opportunistic macroalgal species, such as Cladophora ruchingeri and Pylaiella littoralis, had colonised extensive areas of natural habitat. Our results suggest that biofouling is a persistent issue on mussel farms and that farm structures may act as reservoirs or ‘stepping stones’ for the dispersal of potential marine pests. These distributional and dispersal patterns can inform integrated pest management efforts focusing on spatial management strategies, such as ‘firebreaks’ in farm connectivity, avoidance of pest hotspots, and farm fallowing.
{"title":"Artificial habitat and biofouling species distributions in an aquaculture seascape","authors":"J. Atalah, L. Fletcher, I. Davidson, PM South, B. Forrest","doi":"10.3354/aei00380","DOIUrl":"https://doi.org/10.3354/aei00380","url":null,"abstract":"The global proliferation of marine artificial habitats is rapidly altering the physical structure of coastlines, with knock-on effects on physical, chemical, and ecological processes at seascape scales. Ecological consequences of maritime sprawl associated with aquaculture are poorly understood, despite the fact that these suspended structures are particularly prone to biofouling, which can affect the industry and seascape around it. We characterised seascape-scale spatial and temporal distribution patterns of 10 biofouling taxa in relation to the presence and distance to Perna canaliculus mussel farms in New Zealand’s largest aquaculture region. Seven of 10 taxa had significantly higher cover on farms than in natural habitats throughout the region. The cover of 4 of those 7 taxa, including the high-profile pests Mytilus galloprovincialis and Undaria pinnatifida, exponentially decreased with distance from the nearest farm, while some taxa were absent from natural habitats (e.g. the ascidian Ciona robusta). In contrast, several opportunistic macroalgal species, such as Cladophora ruchingeri and Pylaiella littoralis, had colonised extensive areas of natural habitat. Our results suggest that biofouling is a persistent issue on mussel farms and that farm structures may act as reservoirs or ‘stepping stones’ for the dispersal of potential marine pests. These distributional and dispersal patterns can inform integrated pest management efforts focusing on spatial management strategies, such as ‘firebreaks’ in farm connectivity, avoidance of pest hotspots, and farm fallowing.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"12 1","pages":"495-509"},"PeriodicalIF":2.2,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46630089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Closed recirculation aquaculture systems (RAS) in combination with integrated multitrophic aquaculture (IMTA) are considered best management practices, but high material costs and difficult maintenance still hinder their implementation, especially in developing countries and the tropics. Few case studies of such systems with tropical species exist. For the first time, an extremely low-budget system was tested combining the halophyte sea purslane Sesuvium portulacastrum and a detritivore, sandfish Holothuria scabra, with finfish milkfish Chanos chanos over 8 wk on Zanzibar, Tanzania. In a 2 m3 RAS, milkfish and sea purslane showed good growth, producing an average (±SD) of 1147 ± 79 g fish and 1261 ± 95 g plant biomass, while sea cucumber growth was variable at 92 ± 68 g. The system operated without filter units and did not discharge any solid or dissolved waste. Water quality remained tolerable and ammonia levels were reliably decreased to <1 mg l−1. A NO2 peak occurred within the first 30 d, indicating good biofilter performance of the different system compartments. Changes in dissolved inorganic nitrogen (DIN) species support the notion that the sea cucumber tank was the main site of nitrification, while the hydroponic halophyte tank acted as a net sink of NO3. A nitrogen budget accounted for 63.7 ± 5.3% of the nitrogen added to the system as fish feed. Increasing the plant to fish biomass ratio to 5:1 would fully treat the DIN load. The experiment provides proof-of-concept of a simple pilotscale RAS, integrating tropical species at 3 trophic levels.
{"title":"Low-technology recirculating aquaculture system integrating milkfish Chanos chanos, sea cucumber Holothuria scabra and sea purslane Sesuvium portulacastrum","authors":"Paula Senff, P. Blanc, M. Slater, A. Kunzmann","doi":"10.3354/aei00377","DOIUrl":"https://doi.org/10.3354/aei00377","url":null,"abstract":"Closed recirculation aquaculture systems (RAS) in combination with integrated multitrophic aquaculture (IMTA) are considered best management practices, but high material costs and difficult maintenance still hinder their implementation, especially in developing countries and the tropics. Few case studies of such systems with tropical species exist. For the first time, an extremely low-budget system was tested combining the halophyte sea purslane Sesuvium portulacastrum and a detritivore, sandfish Holothuria scabra, with finfish milkfish Chanos chanos over 8 wk on Zanzibar, Tanzania. In a 2 m3 RAS, milkfish and sea purslane showed good growth, producing an average (±SD) of 1147 ± 79 g fish and 1261 ± 95 g plant biomass, while sea cucumber growth was variable at 92 ± 68 g. The system operated without filter units and did not discharge any solid or dissolved waste. Water quality remained tolerable and ammonia levels were reliably decreased to <1 mg l−1. A NO2 peak occurred within the first 30 d, indicating good biofilter performance of the different system compartments. Changes in dissolved inorganic nitrogen (DIN) species support the notion that the sea cucumber tank was the main site of nitrification, while the hydroponic halophyte tank acted as a net sink of NO3. A nitrogen budget accounted for 63.7 ± 5.3% of the nitrogen added to the system as fish feed. Increasing the plant to fish biomass ratio to 5:1 would fully treat the DIN load. The experiment provides proof-of-concept of a simple pilotscale RAS, integrating tropical species at 3 trophic levels.","PeriodicalId":8376,"journal":{"name":"Aquaculture Environment Interactions","volume":"12 1","pages":"471-484"},"PeriodicalIF":2.2,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46865911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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