Aquaculture Change Research Articles

A photonic sensor system for real‐time monitoring of turbidity changes in aquaculture

AbstractObjectiveThe objective of this study was to test the compatibility and performance of a developed photonic sensor system, which can serve as a dependable and practical device for continuous monitoring of turbidity changes in aquaculture tanks.MethodsThe fabricated photonic sensor system consisted of an integrated data logger and sensor probe. The sensor probe exhibited a precise emission of infrared light at a wavelength of 850 nm. Moreover, the sensor evaluates the ambient light across the red‐green‐blue spectrum. To ensure accuracy and reliability, the entire system underwent a thorough calibration process, referencing nephelometric turbidity unit values acquired through a specialized handheld turbidimeter. Rigorous trials were systematically conducted in 600‐L seawater tanks featuring tubular sea cucumber Holothuria tubulosa and Gilt‐head Sea Bream Sparus auratus to ensure the sensitivity and robustness of the photonic sensor system to the aquaculture environment.ResultA calibration curve revealed a significant correlation between the infrared channel values of the sensor (photon counts) and the turbidity values measured by the turbidimeter. The photonic sensor effectively captured turbidity changes in the aquaculture tanks, with significant differences observed between the tanks. The sensor performance was evaluated in trials with Gilt‐head Sea Bream, which showed sensitivity to high turbidity changes. The photonic sensor system accurately reflects turbidity changes continuously using its own active light source, independent of ambient light intensity, which is essential for turbid water conditions or for taking measurements in total darkness.ConclusionThe photonic sensor is a reliable tool for the continuous and accurate monitoring of turbidity changes in aquaculture systems. However, there are specific usage limitations under low‐turbidity conditions that can be improved in further studies.

Analysis of temporal and spatial dynamics and driving factors in the aquaculture industry of Fuding City, China

BackgroundThe sustainable development of aquaculture is a crucial determinant of food security, the well-being of aquaculture practitioners, and economic growth within coastal regions. Considering the existing gap in research regarding spatial and temporal development of aquaculture, this study investigates the progression of aquaculture practices over time and across various locations in Fuding City, China. MethodsWe retrospectively collected temporal and spatial data on aquaculture, as well as demographic, social, and economic data for Fuding City from 2010 to 2020. By employing 3D kernel density analysis, we illustrated the temporal and spatial changes in aquaculture. Furthermore, we utilized Ordinary Least Squares regression to investigate the driving factors behind the spatial changes in the aquaculture industry. ResultsOver the past decades, we observed that in Fuding City, both the number of fishing rafts and aquaculture households initially decreased and then increased. The spatial distribution of aquaculture experienced a shift from the west (inner bay area) to the east (coastal area). Additionally, the type of fishing rafts also varied by region, with traditional rafts dominating the western inner bay and plastic rafts prevalent in the eastern offshore areas. Analysis of driving factors revealed that at least six factors have a significant positive correlation with the eastward shift of the aquaculture industry's center, including the proportion of migrant population, proportion of aquaculture to total fishery output, average temperature, investment in aquaculture technology, total fish sales, and GDP of Fuding City. ConclusionThis study examines the spatial and temporal dynamics of aquaculture in Fuding City from 2010 to 2020, proposing an innovative approach to spatial optimization that integrates both horizontal and vertical strategies. These insights aim to guide the development of coastal aquaculture policies and support sustainable regional development, fostering a balanced coexistence between human activities and marine environments.

Dynamic Evolution of Aquaculture along the Bohai Sea Coastline and Implications for Eco-Coastal Vegetation Restoration Based on Remote Sensing.

The expansion and intensification of coastal aquaculture around the Bohai Sea in China has reduced the tidal flats and damaged the coastal vegetation environment. However, there are few studies on the relationship between the evolution of coastal aquaculture and the variability of coastal vegetation, which limits our understanding of the impact of human activities on the coastal ecosystem. In this study, based on remote sensing technology, we firstly used a combination of a neural network classifier and manual correction to monitor the long-term dynamic changes in aquaculture in the Bohai Sea from 1984 to 2022. We then analyzed its evolution, as well as the relationship between the evolution of coastal aquaculture and the variability of coastal vegetation, in detail. Our study had three main conclusions. Firstly, the aquaculture along the coast of the Bohai Sea showed an expanding trend from 1984 to 2022, with an increase of 538%. Secondly, the spatiotemporal changes in the aquaculture centroids in different provinces and cities varied. The centroid of aquaculture in Liaoning Province was mainly distributed in the Liaodong Peninsula, and moved northwest; that in Hebei Province was distributed in the northeast and moved with no apparent pattern; the centroid of aquaculture in Tianjin was mainly distributed in the southeast and moved westward; and the centroid of aquaculture in Shandong Province was mainly distributed in the northwest and moved in a northwesterly direction. Finally, the expansion of aquaculture of the Bohai Sea has increased the regional NDVI and length of the corresponding coastline, and has made coastlines move toward the sea. Our results provide reliable data support and reference for ecologically managing aquaculture and coastal environmental protection in the Bohai Sea.

Impacts of disaster and land-use change on food security and adaptation: Evidence from the delta community in Bangladesh

Climate-related disasters severely threaten the livelihoods and food security of millions of Bangladesh is living in deltaic areas. The study looked at shifting patterns of land use, the state of food security, and adaption mechanisms in pre-and post-disaster contexts to anticipate the future situation and its influence on livelihood. The study used Landsat 5 and 8 satellite images to evaluate land cover changes from 1990 to 2015. The study also used various interview tools to assess disaster impacts on land-use change, food security, and adaptive measures. In addition, logistic regression was used to determine land-use change factors and people's perceptions of disaster risk. Satellite image analysis in this study reveals significant positive changes in aquaculture and negative changes in fallow and agricultural land. The changes due to natural disasters considerably affect their socio-ecological system, family income, agriculture production, and out-migration in the study area. Land ownership has a substantial impact on food security. According to the study, disasters disrupt ecosystem services, agriculture production, and food security and impair people's capabilities. Human activity and land accretion are the major physical driving forces influencing land use and land cover changes. People's risk perceptions should be factored into disaster management planning at the local level; this could lead to a better understanding of the policy requirements for reducing food insecurity and poverty in deltaic Bangladesh, as well as strengthening community resilience.

Impacts of population growth in relation to changes in aquaculture and fisheries prices

The paper reviewed the impacts of population growth and the ways it affects aquaculture and fisheries prices. As the world population continues to grow arithmetically, great pressure is placed on arable lands, water, energy, and biological resources to provide an adequate supply of food while maintaining the integrity of the ecosystem. In 2010, FAO projected the world population to double from 6.2 billion in October, 1999 to 12.5 billion in the year 2050. This had created serious negative impacts on the aquaculture and fisheries prices. At present fertile crop lands had been lost at an alarming rates while some abandoned during the past 50 years because erosions made it unproductive. Other vices such as food crisis, political unrest and war (Mexico, Uzbekistan, Turkistan, Yemen, Iraq, Afghanistan, Syria, Morocco and Sudan), civil strife and multiple years of draught (Niger, Mauritania and Senegal), impacts of HIV/AIDS Ebola, Lassa fever and Coronavirus the world over, clashes between cattle rearers and farmers and boko haram issues (Nigeria) as well as kidnapping and corruptions have severely affected aquaculture and fisheries production and accompanied prices. Thus, this review was conducted to raise a cry for farmers and citizens to engage and participate in intensive culture and fisheries practices in order to fill the demand - supply gap so as to make fish food products available for the teeming masses.

Design of a Water Salinity Difference Detector for Monitoring Instantaneous Salinity Changes in Aquaculture

A water salinity difference detector is proposed herein for monitoring instantaneous salinity changes in aquaculture. The detector comprises a water salinity difference sensor and a proposed water salinity difference sensor transducer. The proposed sensor transducer can linearly convert the water salinity difference into a frequency output. Moreover, a technique for automatically changing the sensitivity of the proposed sensor transducer is presented. By using this functionality, the instantaneous salinity changes can be detected with high sensitivity when aquatic organisms are in water with high salinity difference. The performance of the proposed water salinity difference detector was verified through measurements. The measured input current range of the proposed sensor transducer was 12.5– $60~\mu \text{A}$ , and the sensitivities of 1.6, 2.38, 3.17, and 4.05 kHz/ $\mu \text{A}$ were automatically adjusted. The water salinity difference ranged from 7.5 to 35‰, and the sensitivities of 2.492, 2.72, and 3.56 kHz/‰ were also successfully guaranteed. The maximum linear error measured was 0.47%, and the chip area was $1.49\times1.49$ mm2. Finally, a case for monitoring instantaneous salinity changes in aquaculture was developed through experimentation. The results of this study revealed that the proposed chip is suitable for detecting water salinity difference.

Spatio-Temporal Patterns of Coastal Aquaculture Derived from Sentinel-1 Time Series Data and the Full Landsat Archive

Asia is the major contributor to global aquaculture production in quantity, accounting for almost 90%. These practices lead to extensive land-use and land-cover changes in coastal areas, and thus harm valuable and sensitive coastal ecosystems. Remote sensing and GIS technologies contribute to the mapping and monitoring of changes in aquaculture, providing essential information for coastal management applications. This study aims to investigate aquaculture expansion and spatio-temporal dynamics in two Chinese river deltas over three decades: the Yellow River Delta (YRD) and the Pearl River Delta (PRD). Long-term patterns of aquaculture change are extracted based on combining a reference layer on existing aquaculture ponds for 2015 derived from Sentinel-1 data with annual information on water bodies extracted from the long-term Landsat archive. Furthermore, the suitability of the proposed approach to be applied on a global scale is tested based on exploiting the Global Surface Water (GSW) dataset. We found enormous increases in aquaculture area for the investigated target deltas: an 18.6-fold increase for the YRD (1984–2016), and a 4.1-fold increase for the PRD (1990–2016). Furthermore, we detect hotspots of aquaculture expansion based on linear regression analyses for the deltas, indicating that hotspots are located in coastal regions for the YRD and along the Pearl River in the PRD. A comparison with high-resolution Google Earth data demonstrates that the proposed approach can detect spatio-temporal changes of aquaculture at an overall accuracy of 89%. The presented approach has the potential to be applied to larger spatial scales covering a time period of more than three decades. This is crucial to define appropriate management strategies to reduce the environmental impacts of aquaculture expansion, which are expected to increase in the future.

Changes in mangrove vegetation, aquaculture and paddy cultivation in the Mekong Delta: A study from Ben Tre Province, southern Vietnam

In this paper, we analyzed the changes in mangrove forests along the coastal districts of Ben Tre Province in Mekong Delta, in southern Vietnam from 1998 to 2015 using Landsat image series (TM and OLI) using vegetation and water indices, and field data. Decadal changes in aquaculture ponds and area of rice crops were also estimated using satellite and field data in order to understand the influence of intensive aquaculture on mangrove deforestation and agriculture in this region. Furthermore, predictions have been made on the changes in mangrove forests, rice crops and aquaculture ponds in case of 1 m and 2 m sea level rise. About 52.5% of the mangrove forests were cleared between 1998 and 2015 for aquaculture and infrastructure developments in Ben Tre during the study period. Thanh Phu District showed highest loss of mangrove forests (59.3%) and increase in the area covered by aquaculture ponds (120%) during this period. Overall reduction in the rice crops areas in Ben Tre was 23.4% whereas this was 31.5% in the coastal districts due to the conversion of freshwater rice fields into brackish shrimp ponds. It is estimated that a 1 m rise in the current sea level would clear 45.2% of the remaining mangrove forests, 60.9% of the current areas planted with rice, 65% of the aquaculture ponds and 46% of the entire province would be under the water. This study shows a clear picture of the coastal environmental changes going on in the Mekong Delta of Vietnam.

Antimicrobial resistance in Chile and The One Health paradigm: Dealing with threats to human and veterinary health resulting from antimicrobial use in salmon aquaculture and the clinic.

The emergence and dissemination of antimicrobial-resistant bacteria (ARB) is currently seen as one of the major threats to human and animal public health. Veterinary use of antimicrobials in both developing and developed countries is many-fold greater than their use in human medicine and is an important determinant in selection of ARB. In light of the recently outlined National Plan Against Antimicrobial Resistance in Chile, our findings on antimicrobial use in salmon aquaculture and their impact on the environment and human health are highly relevant. Ninety-five percent of tetracyclines, phenicols and quinolones imported into Chile between 1998 and 2015 were for veterinary use, mostly in salmon aquaculture. Excessive use of antimicrobials at aquaculture sites was associated with antimicrobial residues in marine sediments 8 km distant and the presence of resistant marine bacteria harboring easily transmissible resistance genes, in mobile genetic elements, to these same antimicrobials. Moreover, quinolone and integron resistance genes in human pathogens isolated from patients in coastal regions adjacent to aquaculture sites were identical to genes isolated from regional marine bacteria, consistent with genetic communication between bacteria in these different environments. Passage of antimicrobials into the marine environment can potentially diminish environmental diversity, contaminate wild fish for human consumption, and facilitate the appearance of harmful algal blooms and resistant zoonotic and human pathogens. Our findings suggest that changes in aquaculture in Chile that prevent fish infections and decrease antimicrobial usage will prove a determining factor in preventing human and animal infections with multiply-resistant ARB in accord with the modern paradigm of One Health.