Expansion Of Aquaculture Research Articles

Fostering the Development of Western Black Sea Aquaculture: A Scientific Case Study for Finfish Cage Farming Allocated Zone Designation

Mariculture offers enormous potential for providing sustainable food, playing a key role in achieving nutrition security, employment, and Blue Growth. This is particularly true in geographical areas where the dependence of local economies on fishery products is high and yet access to sustainable landings is hindered by environmental drawbacks. One such area is represented by the Black Sea, which offers different degrees of suitability for aquaculture development. While the southern and eastern shores are sheltered enough to allow for the development of large aquaculture activities, the north-western shoreline is characterized by wide environmental fluctuations and the strong influence of the Danube. This study aimed at investigating the suitability of a selected area of the Romanian coast (Mangalia) for finfish cage farming by adapting an internationally endorsed methodology for determining its Degree of Compatibility (DC). The development and expansion of finfish aquaculture depends on the availability of space, so designating Allocated Zones for Aquaculture (AZAs) is essential. The result obtained (DC = 80) indicates that the Mangalia area is suitable for finfish aquaculture activities: there is no major interference with other uses of the maritime space, no conflicts with nature conservation, and the environmental conditions are appropriate for fish culture in floating cages. The novel information provided by this study can be the building block for authorities to settle the governance gap that has so far impeded the development of marine aquaculture in Romania. At a larger scale, this study can serve as a good practice example at the regional Black Sea level.

Dietary replacement of Undaria pinnatifida by Sargassum horneri in feed formulation for abalone Haliotis discus hannai: Effect on growth, gut microbiota, and taste sensory profile

The necessity for additional macroalgal biomass is warranted amid the ongoing expansion of abalone aquaculture. In the current study, an in-depth investigation of the food value of Sargassum horneri as a replacement for Undaria pinnatifida on growth, body composition, body histology, gut microbiota, and the taste sensory profile of abalone Haliotis discus hannai was carried out. After a 12-week feeding trial, the results indicated that 25% replacement (SH25) induced the highest shell-growth performance and best feed utilization values, although there was no significant difference in weight-related growth parameters with the basal (no inclusion of S. horneri) and 50% replacement (SH50) diets. Interestingly, the highest protein content was detected in abalone fed the basal diet followed by SH25 and SH50. The high replacement of S. horneri in the diet showed signs of structural integrity loss in the digestive gland. The results from the pyrosequencing of the genomic DNA from the gut of the abalone indicated an insignificant difference in α-diversity parameters and only a clear boundary was observed between SH0 and SH100 diets based on principal coordinate analysis. The bacterial genera Psychrilobacter, Vibrio, and Mycoplasma predominantly occupied the gut of the abalone, although there is a difference in their relative abundance. The taste screening experiment through the use of an electronic tongue showed a comparable taste profile of the abalone and is independent of the diets given. The findings of the present study showed that S. horneri, up to 50% replacement of macroalgal ingredients, can be utilized in feed formulation for H. discus hannai. These, in turn, contribute to the expanding knowledge on the utilization of biofouling and non-traditional macroalgae for sustainable abalone aquaculture practices.

To Tell or Not to Tell: Preference Elicitation with and without Emphasis on Scientific Uncertainty

<h3>Abstract</h3> Decisions about the optimal use of coastal and marine resources must be taken under high uncertainty about environmental impacts and may conflict with public perception of the risk associated with current blue growth initiatives. In a discrete choice experiment conducted in valuation workshops in five communities in Arctic Norway, we examine public preferences for various aquaculture expansion paths. Respondents prefer a smaller expansion in terms of the number of aquaculture sites compared to the planned expansion. Emphasizing scientific uncertainty regarding the negative environmental impacts of aquaculture leads to lower resistance against the planned expansion.

Comparison of five commercial kits for isolation of total RNA in samples of WSSV-infected shrimp.

Viral diseases are the most serious threat to the expansion and development of shrimp aquaculture. Rapid diagnosis of the white spot syndrome virus (WSSV), a lethal shrimp pathogen, is essential to restrict its spread and reduce the mortality of infected shrimp. This virus has globally affected the shrimp farming industry, with a devastating economic impact. Several studies have focused on the expression of WSSV transcripts to understand the molecular mechanisms governing the pathological development of the disease. Since gene expression studies and molecular diagnostics at the early stages of infection depend on the efficient isolation of high-quality RNA, the extraction methods should be carefully selected. However, previous comparisons of the performance of RNA isolation kits have yet to be systematically investigated. In this study, 5 commercial RNA extraction methods were compared in WSSV-infected shrimp. The highest total RNA yield (ng mg-1 tissue) was obtained using TRIzol. Even though the 260/280 nm absorption ratios showed significant differences, the methods showed good purity values (>2.0). RNA integrity was evaluated in a denaturing agarose gel electrophoresis, and degradation was observed after the total RNA samples were treated with DNase I. Finally, the method that allowed the earlier detection of WSSV transcripts by qRT-PCR was the Zymo Direct-zol RNA MiniPrep kit. This study shows that the amount of observed (or estimated) WSSV transcripts might be affected because of the RNA isolation method. In addition, these results may contribute to improve the accuracy of the results obtained in gene expression studies, for more sensitive and robust detection of WSSV.

The status and challenges of aquaculture development in Dodoma, a semi-arid region in Tanzania

Demand for fish is growing rapidly in Tanzania due to population growth and rising incomes. However, as fewer wild fish are being caught, there is a gap in fish supply. Aquaculture is a viable alternative source to meet the gap in fish demand. Tanzania has the perfect climate and land for fish farming. Aquaculture in fresh and salt water has grown quickly, yet the potential is not being fully tapped. Thus, the study assessed the growth of aquaculture in Dodoma, a rapidly developing semi-arid region of Tanzania, in order to determine its potential, challenges, and solutions. Thirty-six fish farmers from Dodoma urban district were visited and interviewed. The interviews gathered information about management practices, fish yield, and challenges. The findings show that aquaculture in the region began around 9 years ago, when the region began to expand. The aquaculture includes small-scale pond farming of Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus). Fish yield was about 1925 kg ha−1 per culture cycle, and fish customers are definitely available. The main challenges were limited supply and high prices of fish feed and seeds, and limited water supply. Use of commercial feed, pond fertilisation, access to extension services, and ownership of a borehole were related to high fish yields in both species. Expansion of aquaculture in the region is possible with the improvement of extension services and training of farmers in proper breeding, feeding, and water management. To decrease water demands, integrated aquaculture, water recycling, and aquaponics should be encouraged.

Assessment of greenhouse gases emissions and intensity from Chinese marine aquaculture in the past three decades

Marine aquaculture is increasingly gaining importance as a source of food with high nutritional value. However, the expansion of aquaculture could be responsible for water contamination that influences the environmental quality of coastal ecosystems, and emissions of greenhouse gases (GHG) that affect global climate. China is the world's largest producer of marine aquaculture protein, which demands robust studies to assess the corresponding GHG emissions and intensity. To fill in this knowledge gap, the current study quantifies and analyzes GHG emissions and intensity (emission intensity is defined as GHG emissions per unit of production) from Chinese marine aquaculture (marine aquaculture production) over the past 30 years (1991–2020). The production of marine aquaculture comes from the China Fisheries Statistical Yearbooks. And the GHG emissions and intensity were calculated based on five sectors (commercial feed, trash fish, N2O, CH4, and energy) by Emission-Factor Approach. The results suggest that, excluding shellfish and algae, GHG emissions of ten coastal provinces (excluding Shanghai, Hong Kong, Taiwan, and Macau) increased from 2 Mt (109 kg) CO2-eq in 1991 to 25 Mt CO2-eq in 2020. In contrast, GHG emission intensity decreased in the same period from 7.33 (t CO2-eq/t production) to 6.34 (t CO2-eq/t production), indicating a progressive mitigation in GHG emissions per unit of product, hence sustainably satisfying a growing demand for food. As a result, China's marine aquaculture seems to be paving a promising way towards the neutrality of GHG emissions. In most provinces, GHG is on the rise, and only in Tianjin is on the decline in recent years. For the emissions intensity, the values of more than half provinces showed the downtrends. In addition, by considering the ratio of shellfish and algae, Chinese marine aquaculture can improve the net zero goal for GHG emissions of the sector. Finally, results also reveal for the first time the changes in taxonomic composition and spatial GHG emissions and intensity, providing new understanding and scientific bases to elaborate consistent mitigation strategies for an expanding global marine aquaculture.

Computational estimation of sediment symbiotic bacterial structures of seagrasses overgrowing downstream of onshore aquaculture

Coastal seagrass meadows are essential in blue carbon and aquatic ecosystem services. However, this ecosystem has suffered severe eutrophication and destruction due to the expansion of aquaculture. Therefore, methods for the flourishing of seagrass are still being explored. Here, data from 49 public coastal surveys on the distribution of seagrass and seaweed around the onshore aquaculture facilities are revalidated, and an exceptional area where the seagrass Zostera marina thrives was found near the shore downstream of the onshore aquaculture facility. To evaluate the characteristics of the sediment for growing seagrass, physicochemical properties and bacterial ecological evaluations of the sediment were conducted. Evaluation of chemical properties in seagrass sediments confirmed a significant increase in total carbon and a decrease in zinc content. Association analysis and linear discriminant analysis refined bacterial candidates specified in seagrass overgrown- and nonovergrown-sediment. Energy landscape analysis indicated that the symbiotic bacterial groups of seagrass sediment were strongly affected by the distance close to the seagrass-growing aquaculture facility despite their bacterial population appearing to fluctuate seasonally. The bacterial population there showed an apparent decrease in the pathogen candidates belonging to the order Flavobacteriales. Moreover, structure equation modeling and a linear non-Gaussian acyclic model based on the machine learning data estimated an optimal sediment symbiotic bacterial group candidate for seagrass growth as follows: the Lachnospiraceae and Ruminococcaceae families as gut-inhabitant bacteria, Rhodobacteraceae as photosynthetic bacteria, and Desulfobulbaceae as cable bacteria modulating oxygen or nitrate reduction and oxidation of sulfide. These observations confer a novel perspective on the sediment symbiotic bacterial structures critical for blue carbon and low-pathogenic marine ecosystems in aquaculture.

Aquaculture in tourist destinations: the need to consider economic aspects in environmental impact studies

ABSTRACT The search for sustainable alternative food sources has led to the expansion of aquaculture, with the proliferation of marine farms in more and more places, some of them very touristic. The installation of these farms in the waters of consolidated Sun and Beach tourist destinations represents a planning challenge, which requires consideration of the potential environmental and economic impacts of those activities on tourism attractions. This article critically analyzes the implementation of marine farms in the Costa Blanca (Alicante), one of the most consolidated Sun and Beach tourist destinations in the Mediterranean. The case study shows that the environmental impact studies and other documentation accompanying these projects do not include tourism aspects, which represents a deficiency that jeopardizes the economic and social sustainability of the projects.

Temporal dynamics of lateral carbon export from an onshore aquaculture farm

Many coastal areas are hotspots of aquaculture expansion, where the overuse of artificial feeds results in the accumulation of organic carbon in nearshore aquaculture ponds. In rural areas, wastewater from the aquaculture ponds is discharged to the nearshore waters through artificial ditches causing lateral carbon export from the land to the ocean. Such flux may be meaningful in coastal carbon budgets since aquaculture is the hotspot of carbon sequestration and storage. To quantify the magnitude and temporal dynamics of lateral carbon export from aquaculture ponds, we used high-frequency in-situ monitoring of turbidity, fluorescent dissolved organic matter, etc. across different temporal scales. We measured water levels and velocity profiles in a ditch cross-section to obtain year-round water exchange. Carbon export was integrated from water fluxes and organic carbon concentrations. Our results suggested that aquaculture ponds were a source of particular organic carbon (POC) and dissolved organic carbon (DOC). The net lateral flux of POC and DOC was 148 ± 38 kg yr−1 and 296 ± 18 kg yr−1. Temporally, the export of POC and DOC is influenced by both tides and wastewater discharge. Under the disturbance with aquaculture wastewater discharge, the mean DOC export in the ditch increased by 497 kg, which was 1.5 times that of the undisturbed; the mean POC export increased by 190 kg, which was 1.8 times that of the undisturbed. Thus, aquaculture activities can considerably disturb the coastal carbon balance by facilitating carbon-rich fluid exchange from onshore farms to nearshore estuaries. As aquaculture expands across Asia and the globe, this study provides important insights into the impacts of aquaculture on coastal carbon budgets.

Trade-offs in the transition to a blue economy - Mapping social acceptance of aquaculture expansion in Norway

Aquaculture is currently the fastest growing food industry globally, and proposed expansion plans include substantial increases in production over the next decades. While this will improve global food security, contribute to the blue economy and create jobs locally, the potential negative impacts on the marine environment could be massive. The existing literature suggests that further research needs to be conducted into the dynamic nature of the social-ecological systems which host aquaculture. This paper presents the results of a choice experiment survey of Norwegian households' trade-offs between salmon production and job creation, and the detrimental impacts on the marine environment. Most respondents were at the outset neutral or supportive of plans for a substantial increase in aquaculture production. However, when informed about potential environmental impacts in terms of marine plastics and salmon lice affecting wild salmon stocks, and asked to trade these off against the positive effects, the majority opposed the plans and expressed a positive willingness-to-pay to avoid the planned expansion. Applying a hybrid mixed multinomial logit model we find that income, education and to some extent age, along with environmental attitudes, explain most of the variation in people's preferences. Support for large aquaculture expansion is higher among people who consume farmed salmon frequently and those living in areas with a high density of aquaculture farms. Hence, we do not find the so-called “not in my backyard” (NIMBY) effect. These results, which arguably contrast with previous studies of environmental impacts from aquaculture, can be useful for public planners globally as they consider expanding the blue economy.

Current status and development prospects of aquatic vaccines.

Diseases are a significant impediment to aquaculture's sustainable and healthy growth. The aquaculture industry is suffering significant financial losses as a result of the worsening water quality and increasing frequency of aquatic disease outbreaks caused by the expansion of aquaculture. Drug control, immunoprophylaxis, ecologically integrated control, etc. are the principal control strategies for fish infections. For a long time, the prevention and control of aquatic diseases have mainly relied on the use of various antibiotics and chemical drugs. However, long-term use of chemical inputs not only increases pathogenic bacteria resistance but also damages the fish and aquaculture environments, resulting in drug residues in aquatic products, severely impeding the development of the aquaculture industry. The development and use of aquatic vaccines are the safest and most effective ways to prevent aquatic animal diseases and preserve the health and sustainability of aquaculture. To give references for the development and implementation of aquatic vaccines, this study reviews the development history, types, inoculation techniques, mechanisms of action, development prospects, and challenges encountered with aquatic vaccines.

Applying the DPSIR framework to qualitatively assess the globally important mangrove ecosystems of Indonesia: A review towards evidence-based policymaking approaches

Indonesia has the largest extent of mangroves globally, supporting communities at the local scale while contributing to climate change mitigation at the global scale. Yet, they are highly threatened by multiple anthropogenic and natural stressors. Thus, in this study, we aim to qualitatively assess Indonesia’s mangrove ecosystems by conducting a literature review applying the Driver-Pressure-State-Impact-Response (DPSIR) framework. By using the framework, we identified multiple stressors and existing management efforts in 27 provinces of Indonesia. For instance, we identified aquaculture expansion as the most frequented driver of mangrove loss leading to the conversion of mangroves to shrimp farms in 20 provinces. In terms of responses, mangrove rehabilitation and community-based management have a long history in Indonesia while economic valuation and payment of ecosystem services are yet to be established across the country. The identification of multiple stressors and/or threats is instrumental to addressing the causes of degradation of globally-important mangroves in Indonesia if effectively translated into policies, which remains a future challenge.

Safeguarding Imperiled Biodiversity and Evolutionary Processes in the Wallacea Center of Endemism.

Wallacea-the meeting point between the Asian and Australian fauna-is one of the world's largest centers of endemism. Twenty-three million years of complex geological history have given rise to a living laboratory for the study of evolution and biodiversity, highly vulnerable to anthropogenic pressures. In the present article, we review the historic and contemporary processes shaping Wallacea's biodiversity and explore ways to conserve its unique ecosystems. Although remoteness has spared many Wallacean islands from the severe overexploitation that characterizes many tropical regions, industrial-scale expansion of agriculture, mining, aquaculture and fisheries is damaging terrestrial and aquatic ecosystems, denuding endemics from communities, and threatening a long-term legacy of impoverished human populations. An impending biodiversity catastrophe demands collaborative actions to improve community-based management, minimize environmental impacts, monitor threatened species, and reduce wildlife trade. Securing a positive future for Wallacea's imperiled ecosystems requires a fundamental shift away from managing marine and terrestrial realms independently.

Assessment of Environmental Impact of Aquaculture Ponds in the Western Delta Region of Andhra Pradesh

Aquaculture is persistent and well-established in the delta region of Andhra Pradesh. In recent years, the expansion of aquaculture has conferred positive economic growth in the newly formed state. However, the enormous development of aqua ponds increases the effluents from aquaculture which contain various chemical compounds that can cause negative impacts when released into the environment. This paper presents the effect of unengineered aquaculture on the environment in the delta region of Andhra Pradesh. The expansion rate of aquaculture practice in the delta region has been carried out using remote sensing and a geospatial information system. An experimental investigation was carried out on soil and water samples collected from the aquaculture ponds to evaluate the water quality parameters and soil characterization. Analysis of the geotechnical properties and microstructure was carried out to determine the interaction between the soil and the aquaculture contaminants. Based on the geospatial data and field survey, the aquaculture practice in the delta region of Andhra Pradesh was intensive and extended towards the northeast from the southwest. Between 2016 and 2020, aquaculture practice significantly increased by 6.08%. Moreover, the water quality parameters and pond bottom soil showed a higher concentration of ammonia and nitrates. Further, aquaculture leachate may interact with the subsoil and have a negative impact on soil mineralogy and hydraulic conductivity. The extensive experimental data and field surveys reveal that adequate guidelines are needed to control the pollution load on the ecosystem.

RaftNet: A New Deep Neural Network for Coastal Raft Aquaculture Extraction from Landsat 8 OLI Data

The rapid development of marine ranching in recent years provides a new way of tackling the global food crisis. However, the uncontrolled expansion of coastal aquaculture has raised a series of environmental problems. The fast and accurate detection of raft will facilitate scientific planning and the precise management of coastal aquaculture. A new deep learning-based approach called RaftNet is proposed in this study to extract the coastal raft aquaculture in Sansha Bay using Landsat 8 OLI images accurately. To overcome the issues of turbid water environments and varying raft scales in aquaculture areas, we constructed the RaftNet by modifying the UNet network with dual-channel and residual hybrid dilated convolution blocks to improve the extraction accuracy. Meanwhile, we adopted the well-known semantic segmentation networks (FCN, SegNet, UNet, UNet++, and ResUNet) as the contrastive approaches for the extraction. The results suggested that the proposed RaftNet model achieves the best accuracy with a precision of 84.5%, recall of 88.1%, F1-score of 86.30%, overall accuracy (OA) of 95.7%, and intersection over union (IoU) of 75.9%. We then utilized our RaftNet to accurately extract a raft aquaculture area in Sansha Bay from 2014 to 2018 and quantitatively analyzed the change in the raft area over this period. The results demonstrated that our RaftNet is robust and suitable for the precise extraction of raft aquaculture with varying scales in turbid coastal waters, and the Kappa coefficient and OA can reach as high as 88% and 97%, respectively. Moreover, the proposed RaftNet will unleash a remarkable potential for long time-series and large-scale raft aquaculture mapping.

Stable isotope and fatty acid analysis reveal the ability of sea cucumbers to use fish farm waste in integrated multi-trophic aquaculture

Stable isotope ratios, carbon (δ13C) and nitrogen (δ15N), and fatty acids validated the trophic connection between farmed fish in a commercial nearshore fish farm and sea cucumbers in the Mediterranean Sea. This dual tracer approach evaluated organic matter transfer in integrated multi-trophic aquaculture (IMTA) and the ability of sea cucumbers to incorporate fish farm waste (fish faeces and uneaten artificial fish feed) into their tissue. Between October 2018 and September 2019, Holothuria (Roweothuria) poli Delle Chiaje, 1824, co-cultured at IMTA sites directly below one of the commercial fish cage , at 10m and 25m from the selected fish cage, and at two reference sites over 800m from the fish farm. Sea cucumbers were sampled from each site in February, May and September, except at 0m due to mass mortalities recorded here in the first month of study. Isotopic mixing models revealed that fish farm organic waste was the dominant dietary source for H. poli in IMTA at 10m and 25m from the cage. The contribution of marine plant-derived organic matter, Posidonia oceanica leaves and rhizomes, was least important. The isotopic signatures of sea cucumber tissues at reference sites were not explained by the sampled food resources. Importantly, fatty acid profiling revealed a high abundance of individual terrestrial plant fatty acids, such as oleic (18:1n-9), linoleic (18:2n-6) and eicosenoic (20:1n-9) acids in sea cucumber tissue at 10m and 25m from the fish cage, presumably linked to the terrestrial plant oil content of the fish feeds. At the reference sites, sea cucumber tissues were characterised by higher relative abundance of arachidonic acid (20:4n-6) acid, and the natural marine-based eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids. These analyses revealed important differences in the composition of H. poli between the IMTA and reference locations, driven by aquaculture-derived waste near fish cages. Moreover, this study revealed temporal variation in food availability and quality, and possible differences in the physiological responses of H. poli. Stable isotope analysis and fatty acid profiling provided complementary evidence for the important dietary preferences of H. poli and validated the potential of sea cucumbers to uptake aquaculture organic waste as part of inshore fish-sea cucumber IMTA. It reveals the important implications that an established trophic link has on the viability of using sea cucumbers for the development of IMTA and the sustainable expansion of aquaculture.

Expansion of aquaculture threatens the existence of wetlands in Bangladesh

Despite positive role of aquaculture in food production, the practice may impact the environment negatively and it is difficult to quantify the loss. In this study, we assessed land use changes in four important wetlands (Hardoho Beel, Angrar Beel, Shaoil Beel and Gopalpur Beel) of Bangladesh through analysis of historical satellite images (1990 – 2020) to show how expansion of aquaculture activities threatens the existence of freshwater wetlands. Since 1990, the water area of all four wetlands decreased significantly over time (all p &lt; 0.001). Mean yearly loss of 47.9 ± 79.3 ha, 99.2 ± 185.5 ha, 51.2 ± 61.9 ha and 2.6 ± 4.7 ha were recorded for Hardoho Beel, Angrar Beel, Shaoil Beel and Gopalpur Beel respectively. A decreasing trend in wetland area was recorded in all wetlands, primarily due to excavation of aquaculture ponds. In 2020, aquaculture ponds represented 72% of the core wetland areas. Two wetlands (Hardoho and Gopalpur) were almost totally lost and converted to aquaculture ponds and agricultural lands. This study concludes that the existence of freshwater wetlands in Bangladesh is at stake and recommends further studies to determine its impacts on people's livelihood and biodiversity.

Global Mangrove Extent Change 1996–2020: Global Mangrove Watch Version 3.0

Mangroves are a globally important ecosystem that provides a wide range of ecosystem system services, such as carbon capture and storage, coastal protection and fisheries enhancement. Mangroves have significantly reduced in global extent over the last 50 years, primarily as a result of deforestation caused by the expansion of agriculture and aquaculture in coastal environments. However, a limited number of studies have attempted to estimate changes in global mangrove extent, particularly into the 1990s, despite much of the loss in mangrove extent occurring pre-2000. This study has used L-band Synthetic Aperture Radar (SAR) global mosaic datasets from the Japan Aerospace Exploration Agency (JAXA) for 11 epochs from 1996 to 2020 to develop a long-term time-series of global mangrove extent and change. The study used a map-to-image approach to change detection where the baseline map (GMW v2.5) was updated using thresholding and a contextual mangrove change mask. This approach was applied between all image-date pairs producing 10 maps for each epoch, which were summarised to produce the global mangrove time-series. The resulting mangrove extent maps had an estimated accuracy of 87.4% (95th conf. int.: 86.2–88.6%), although the accuracies of the individual gain and loss change classes were lower at 58.1% (52.4–63.9%) and 60.6% (56.1–64.8%), respectively. Sources of error included misregistration in the SAR mosaic datasets, which could only be partially corrected for, but also confusion in fragmented areas of mangroves, such as around aquaculture ponds. Overall, 152,604 km2 (133,996–176,910) of mangroves were identified for 1996, with this decreasing by −5245 km2 (−13,587–1444) resulting in a total extent of 147,359 km2 (127,925–168,895) in 2020, and representing an estimated loss of 3.4% over the 24-year time period. The Global Mangrove Watch Version 3.0 represents the most comprehensive record of global mangrove change achieved to date and is expected to support a wide range of activities, including the ongoing monitoring of the global coastal environment, defining and assessments of progress toward conservation targets, protected area planning and risk assessments of mangrove ecosystems worldwide.

Trophic state index ( TSI ) and carrying capacity estimation of aquaculture development; the application of total phosphorus budget

The aquaculture industry is crucial for sustainability and food security. Nevertheless, it is also one of the significant causes of water quality degradation, reducing water bodies' carrying capacity. One of the degradation factors is the improper discharge of phosphorus. This study aimed to evaluate the trophic state index (TSI) and carrying capacity for tilapia aquaculture development at the Temengor Reservoir, Malaysia, based on the Dillon–Rigler phosphorus budget model. The data permit the evaluation of the limit for fish production capacities that could retain acceptable water quality conditions. This study was carried out monthly from January 2014 to May 2015, focusing on cage sites within the Aquaculture Industrial Zone (AIZ). A total of 15 sampling points were established within a 5-km radius of the fish cages at 1 km horizontal intervals. The TSI values based on three indicators, total phosphorous, Secchi depth and chlorophyll-a, showed a significant difference (p < 0.05) among sampling points. Areas in the vicinity of the fish cages (<3 km) were at a eutrophic state. However, the current aquaculture production at 9.13 × 103 tonnes per year, which comprises three fish cage modules, has not yet reached the optimum capacity of 325.23 × 103 tonnes per year. Although the lake could accommodate another 105 fish cages, the eutrophic state near the cages signalled water quality deterioration. As there is a plan to increase the number of cages, it is hoped that these findings will be taken into serious consideration in the implementation of any aquaculture expansion in this man-made lake.

Ecological niche models for the assessment of site suitability of sea cucumbers and sea urchins in China

In the present study, the maximum entropy model (MaxEnt) based on the data of sea surface temperature (SST) and published information was used to assess the site suitability for the aquaculture expansion of the sea cucumber Apostichopus japonicus and the sea urchin Strongylocentrotus intermedius in China. According to the current assessment, the coastal areas of Hebei province and Tianjin have great prospects for A. japonicus aquaculture, while is currently being underutilized. In the south, more than 94% of the coastal areas in Zhejiang, Fujian, and Guangdong provinces are suitable for the growth of A. japonicus for six months, especially the coastal areas of Lianjiang, Changle, Fuqing and Putian in Fujian province. The water temperatures in more than 94% of China's coastal areas are higher than 25 °C in July and August, which probably results in the mortality of S. intermedius in aquaculture. This clearly indicates that high water temperature is the bottleneck of S. intermedius aquaculture and well explains the limited expansion of this commercially important exotic species since the introduction in 1989. We suggest a new aquaculture model of S. intermedius that extends the seed production to November to avoid the mass mortality in summer. In the south, 64% of coastal areas in Zhejiang and Fujian provinces are suitable for the transplantation of S. intermedius to the south. The present study suggests the ecological niche model MaxEnt based on the data of SST and published information as a new tool for the assessment of the site suitability of sea cucumbers and sea urchins in China. This provides new insights into the aquaculture expansion of native and exotic species.