Aquaculture Resources Research Articles

Improved growth performance and physiological state in hybrid abalone (Haliotis rufescens and Haliotis fulgens) facing ocean acidification conditions

Abalone (Haliotis spp.) is a valuable global aquaculture resource in Mexican abalone industry, particularly red (Haliotis rufescens) and green (H. fulgens) abalone, showing significant growth. However, climate change -particularly ocean acidification (OA)- threatens production by negatively impacting mollusks, leading to recruitment failures, poor fertilization, malformations, and reduced calcification and growth jeopardizing sustainability and food security. This study aims to assess robustness of a hybrid abalone cross RF (H. rufescens ♀ x H. fulgens ♂) to OA conditions by evaluating biological performance (survival, growth in weight and length) and metabolic response (oxygen consumption, ammonia excretion rate, and atomic O:N ratio). Juveniles from hybrid RF cross and two pure parental crosses (RR, FF) were exposed to three pH levels: control (pH ≈ 8.0) and two reduced pH scenarios (pH 7.8 and 7.5), representing moderate and severe OA conditions. The results showed hybrid cross exhibiting better growth and metabolic response than pure crosses under all conditions. Notably, hybrid length growth was superior under moderate OA conditions (pH 7.8) compared to control (pH 8.0) and intense OA conditions (pH 7.5). Enhanced physiological hybrid status was evidenced by increased oxygen consumption and stable ammonia excretion, reflected in higher atomic O:N ratio. This study demonstrates hybrid cross RF robustness under OA conditions and supports interspecific hybridization as potential mitigation strategy to alleviate negative OA effects for sustainable abalone production.

UICE-MIRNet guided image enhancement for underwater object detection

Underwater object detection is a crucial aspect of monitoring the aquaculture resources to preserve the marine ecosystem. In most cases, Low-light and scattered lighting conditions create challenges for computer vision-based underwater object detection. To address these issues, low-colorfulness and low-light image enhancement techniques are explored. This work proposes an underwater image enhancement technique called Underwater Image Colorfulness Enhancement MIRNet (UICE-MIRNet) to increase the visibility of small, multiple, dense objects followed by underwater object detection using YOLOv4. UICE-MIRNet is a specialized version of classical MIRNet, which handles random increments of brightness features to address the visibility problem. The proposed UICE-MIRNET restrict brightness and also works on the improvement of the colourfulness of underwater images. UICE-MIRNet consists of an Underwater Image-Colorfulness Enhancement Block (UI-CEB). This block enables the extraction of low-colourful areas from underwater images and performs colour correction without affecting contextual information. The primary characteristics of UICE-MIRNet are the extraction of multiple features using a convolutional stream, feature fusion to facilitate the flow of information, preservation of contextual information by discarding irrelevant features and increasing colourfulness through proper feature selection. Enhanced images are then trained using the YOLOv4 object detection model. The performance of the proposed UICE-MIRNet method is quantitatively evaluated using standard metrics such as UIQM, UCIQE, entropy, and PSNR. The proposed work is compared with many existing image enhancement and restoration techniques. Also, the performance of object detection is assessed using precision, recall, and mAP. Extensive experiments are conducted on two standard datasets, Brackish and Trash-ICRA19, to demonstrate the performance of the proposed work compared to existing methods. The results show that the proposed model outperforms many state-of-the-art techniques.

Chromosome-scale genome assembly of the tropical abalone (Haliotis asinina)

Abalone (family Haliotidae) are an ecologically and economically significant group of marine gastropods that can be found in tropical and temperate waters. To date, only a few Haliotis genomes are available, all belonging to temperate species. Here, we provide the first chromosome-scale abalone genome assembly and the first reference genome of the tropical abalone Haliotis asinina. The combination of PacBio long-read HiFi sequencing and Dovetail’s Omni-C sequencing allowed the chromosome-level assembly of this genome, while PacBio Isoform sequencing across five tissue types enabled the construction of high-quality gene models. This assembly resulted in 16 pseudo-chromosomes spanning over 1.12 Gb (98.1% of total scaffolds length), N50 of 67.09 Mb, the longest scaffold length of 105.96 Mb, and a BUSCO completeness score of 97.6%. This study identified 25,422 protein-coding genes and 61,149 transcripts. In an era of climate change and ocean warming, this genome of a heat-tolerant species can be used for comparative genomics with a focus on thermal resistance. This high-quality reference genome of H. asinina is a valuable resource for aquaculture, fisheries, and ecological studies.

Synthesis of 6-bromo-7-arylaminoisoquinoline-5,8-quinones and its effects on Piscirickettsia salmonis infection invitro.

Among the most important aquaculture resources for our country, salmon and trout stand out. Their production has increased significantly in recent decades, making them two of the most valuable resources in economic terms. However, high aquaculture production has allowed many pathogens to proliferate, causing infectious diseases and significant production losses. Piscirickettsia salmonis is a gram-negative, facultative intracellular bacterium that is responsible for causing severe disease in a variety of salmonid fish species. Despite the significant impact of P. salmonis on aquaculture, effective treatments for this disease remain limited. Current prevention and control strategies often include antibiotics and vaccines. However, these treatments have shown varying degrees of efficacy. A promising approach involves synthesizing bioactive analog compounds with antibacterial properties. Quinones, secondary metabolites that are abundant in nature, have become a focal point of interest due to their diverse physiological activities, including antibiotic, insecticidal, antifungal, and anticancer properties. In this study, it is shown the synthesis of series 6-bromo-7-arylaminoisoquinoline-5,8-quinones, the characterization of these compounds using classical spectroscopic methods such as one-dimensional nuclear magnetic resonance (NMR), FT-IR (infrared), mass spectrometry, and the biological activity against Piscirickettsia salmonis. The brominated derivative compounds showed no cytotoxicity at any concentration evaluated. Furthermore, the infectivity of P. salmonis after treatment with the analog compounds indicated that derivatives methyl 6-bromo-7-((4-methoxyphenyl)amino)-1,3-dimethy-5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylate (4b) and methyl 7-((4'-amino-[1,1'-biphenyl]-4-yl)amino)-6-bromo-1,3-dimethy-5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylate (4g) reduced the bacterial load at 25 μg/mL concentration.

Genetic Variability in Mediterranean Coastal Ecosystems: Insights into Ostrea spp. (Bivalvia: Ostreidae).

Oysters are sessile, filter-feeding bivalve molluscs widely distributed in estuarine and coastal habitats worldwide. They constitute a valuable resource for fisheries and extensive aquaculture and provide essential ecological services. Yet, their genetic diversity and distribution remain understudied. The variability in shell morphology complicates species classification, which is influenced by environmental and genetic factors. Although molecular phylogenetics research has refined oyster taxonomy and identified approximately 100 extant species, numerous taxonomic uncertainties persist. In the present study, we aimed to document the occurrence of small flat oysters of the genus Ostrea along the Mediterranean coastal areas of Liguria and Sardinia (Italy). Specifically, 16S rRNA sequence data were used to identify Ostrea species. Our findings offer novel insights into the O. stentina species complex and O. neostentina, a new species in the Mediterranean coastal areas of Italy. The study data further our understanding of Ostrea species diversity, distribution, and evolutionary patterns.

Mental models of aquaculture governance in Indonesia

Aquaculture stakeholders have mental models, which are the internal cognitive representations of how they understand and prioritize the different features of their aquaculture systems. Individuals and stakeholder groups are likely to have different mental models, with implications for making cooperative governance work and guiding the rapidly emerging sector’s sustainable development. We apply a participatory approach called fuzzy cognitive mapping to capture and compare the mental models of community-based coastal pond aquaculture stakeholders in Indonesia, including farmers, government managers, and researchers who need to work together to govern a rapidly expanding aquaculture sector which faces critical sustainability challenges. To conceptually structure our comparison, we use Elinor Ostrom’s social–ecological systems framework. Our results highlight important differences between stakeholder group mental models which represent potential conflicts of interest and barriers for collaborative governance. Fish farmer models emphasize resource system challenges relating to production instability and risk, while government managers emphasize increasing production intensity to meet sectoral growth targets. Researchers, in contrast, tend to focus on pond waste treatment and water quality management. Governance attributes were consistently perceived as less frequent and less influential compared to other social–ecological dimensions, reflecting perceptions of weak governance in the sector. We identify a critical need for programs aimed at strengthening community-level institutional arrangements for governing shared aquaculture resources, increasing technical knowledge capacity, and managing financial risk. By merging all stakeholder models into a single “community” model, we identify key consensus action situations across the three groups as potential focal points for aquaculture development which may serve as a starting point for actors to work together to identify context-appropriate institutional solutions to these sustainability challenges.

From image-level to pixel-level labeling: A weakly-supervised learning method for identifying aquaculture ponds using iterative anti-adversarial attacks guided by aquaculture features

Aquaculture mapping is essential for monitoring and managing aquaculture resources. However, accurately geotargeting individual aquaculture ponds from medium-resolution remote sensing imagery remains challenging, and convolutional deep learning methods for identifying aquaculture ponds require labor-intensive pixel-level annotations. This paper presents a novel weakly-supervised learning method to derive pixel-level labels from image-level annotations for aquaculture ponds. Our approach uses iterative anti-adversarial attacks to refine localization results from multi-scale class activation maps (CAMs). The improved method integrates two regularization methods guided by aquaculture features to form a joint loss function for adversarial samples: discriminative water region suppression and non-aquaculture water class suppression. We also propose an aquaculture feature termed CFNDWI to constrain the localization results and generate high-quality pseudo-labels. As a result, the pseudo-labels are used to train semantic segmentation networks for accurately identifying aquaculture ponds. We evaluated the performance of our method using commonly-used backbones on 10 m Sentinel-2 imagery. Our method achieves Intersection over Union (IoU) values of 0.618–0.655 for pseudo-label generation, and IoU values of 0.664–0.708 for semantic segmentation, outperforming state-of-the-art weakly-supervised methods and public datasets. The effectiveness of each module of our method was also testified through ablation experiments. Our method leverages knowledge-driven aquaculture features to guide the data-driven adversarial learning process, addressing the lack of high-quality aquaculture datasets for model training. The code for implementing our method will be accessible at https://github.com/designer1024/WSLM-AQ.

The Presentation of the Risks That Oil Pollution Poses to Aquaculture

Aquaculture has emerged as the most rapidly growing technology for food production on a global scale. The current growth trajectory of aquaculture production surpasses that of all other meat production types and is anticipated to persist in its ascent with the continuous expansion of the agriscience industry. The contribution of aquaculture to food security varies based on species and country, either directly through domestic consumption or indirectly through the stimulation of economic growth via exports. In Türkiye, the share of aquaculture in overall production has increased over the years and has become a significant contributor to the country’s economic development through exports. Fish farms concentrated in the Eastern Black Sea and Southern Aegean regions also draw attention due to their proximity to sea areas with intense maritime activities. Potential marine pollution in these regions poses a serious risk to these economically important resources, making it crucial to predict the extent of this risk in advance and take preventive measures. This study aims to simulate, through a scenario, how a possible oil spill in the Southern Aegean region would spread in the sea, how quickly it would reach the fish farms in this region, and how long it would take to impact the fish population to a certain extent. The values derived from this simulation will shed light on intervention plans to be implemented by both local and central authorities, serving as exemplary models for formulating similar plans for all aquaculture resources.

Metals and Natural Radioactivity Investigation of Danube River Water in the Lower Sector

In this paper high-resolution continuum source atomic absorption spectrometry (HRCS AAS) was used for the determination of metal concentrations in Danube water collected in the river lower sector in SE Romania (Braila-Galati-Tulcea). The evaluation of the water natural radioactivity was only performed in Galati sector based on selected radiological parameters: gross alpha/beta activity and radionuclides (210Po, 210Pb, natU, natTh and 226Ra) activity concentrations. The results indicate a temporal and spatial variability of contaminant levels due to anthropogenic inputs and seasonal conditions. For several heavy metals, the registered concentrations exceed the legislated values, imposing a regular monitoring of water quality especially in the case of using the water resource for human consumption, irrigation or aquaculture.

Refining the Farm Aquaculture Resource Management Model for Shellfish Nitrogen Removal at the Local Scale

Nutrient-related environmental degradation in coastal waters is a continuing global problem. Bivalve shellfish farms show nutrient removal capabilities similar to some traditional management strategies and in some places have been incorporated into nutrient management programs to help achieve water quality goals. Bioextractive nutrient removal varies by farmed species and is influenced by environment parameters; thus, data and information for both are needed to estimate nutrient mitigation potential of shellfish farms. The Farm Aquaculture Resource Management (FARM) model, calibrated for farmed species, uses local environmental and farming practice data to simulate interactions between the farmed population and the local environment and to optimize cultivation practices for economic gain. We calibrated the model to predict nitrogen removal by Eastern oyster (Crassostrea virginica) farms with specific field and experimental data on oysters, their local environment, and farm practices in Long Island Sound, CT, USA. Previous FARM applications were not validated for nitrogen removal with local data. In the harvest when ready (HWR) model scenario (oysters are harvested when they reach harvest size), the farm removed 159 kg N ha−1 year−1 while the non-HWR scenario (all oysters are harvested at one time) removed 274 kg N ha−1 year−1. These estimates are within the range of previously reported in-water bioextraction studies in the Northeastern USA. The robust outputs from this validated model can be reliably used in marine spatial planning efforts and by nutrient managers to predict the nitrogen removal benefits that could be achieved through new or expanded eastern oyster farms in eutrophic environments.

Spatial Distribution and Differentiation Analysis of Coastal Aquaculture in China Based on Remote Sensing Monitoring

Multiple datasets related to pond and marine aquaculture have been published using diverse remote sensing technologies, yet a comprehensive dataset detailing spatial distribution on both land and sea sides is lacking. Firstly, a meticulous comparison of datasets which we selected related to aquaculture ponds and marine, ensuring consistency in trends. Subsequently, the datasets published by our team were edited and integrated to illustrate aquaculture activities on both sides of China’s coastal zone. Finally, a spatial differentiation of coastal aquaculture in major provinces was analyzed. This analysis also utilizes the types of coastline and statistical data, guiding coordinated resource management efforts. The results unveil a distinctive spatial distribution pattern, concentrating aquaculture in the northern regions—Bohai Sea, Jiangsu, Fujian, and Pearl River coasts in Guangdong. The provinces rich in aquaculture resources, such as Shandong, Guangdong, and Liaoning, exhibit extensive coastlines. However, remote sensing monitoring suggests an underestimation of Liaoning’s marine aquaculture compared to statistical yearbook data. Furthermore, southern provinces like Guangdong and Fujian exhibit significantly higher aquaculture output than Liaoning. Zhejiang leads in fishing output. The paper outlines the future development direction of coastal aquaculture, emphasizing a strategic, integrated land–sea approach for sustainable development.

Harnessing the Potential of Naturally-stabilized Earthen Ponds for Hill Aquaculture: A Demonstration Using Fish Species Combinations in Meghalaya

Aquaculture plays a pivotal role in sustaining livelihoods in the hilly regions of India. However, these areas face challenges in aquaculture production due to prolonged cold climates and suboptimal water temperatures. This study aimed to develop a low-input aquaculture system tailored for hilly conditions in Meghalaya, Northeast India, by employing naturally-stabilized earthen ponds. Ranging in area from 700 to 1500 m2 and with a depth of 1.5 to 2m, these ponds were stocked with fish of different feeding niches at a density of 5000 fish per hectare, with the following compositions: 20% Catla, 40% Rohu, and 40% Gonia in Pond 1; 20% Catla, 40% Rohu, and 40% Common carp in Pond 2; and 20% Catla, 40% Rohu, 20% Gonia, and 20% Common carp in Pond 3. The average size was 28.4±1.8 g for Catla, 7.5±0.4 g for Rohu, 7.6±0.5 g for Gonia, and 10.8±1.3 g for Common carp. The culture duration spanned 8 months, with the initial two months involving feeding fish with commercial feed and the subsequent 6 months with farm-made feed at 2% body weight. Monthly assessments of water quality parameters and bi-monthly evaluations of fish growth attributes were conducted. Analysis of water temperature revealed suboptimal average temperatures ranging from 19.5°C to 20.2°C. Fish production attributes at the end of 8-month was found to be better in Pond 2 (survival 83.2%; biomass 1227.5 kg/ha; FCR 1.53), followed by Pond 3 (survival 82.3%; biomass 1114.8 kg/ha; FCR 1.60) and Pond 1 (survival 81.1%; biomass 998.7 kg/ha; FCR 1.64). Ponds containing Common carp exhibited lower biomass, potentially due to their aggressive feeding behavior leading to competition with co-habiting fishes. It is concluded that naturally-stabilized earthen ponds in hilly areas could serve as a valuable resource for hill aquaculture. However, optimizing productivity requires appropriate fish combinations to minimize inter-specific competitions.

Specific Diversity of Fish Ponds in the Haut-sassandra and Risks of Contamination by Potential Pathogens among Oreochromis niloticus (Tilapia)

Fishery and aquaculture products are an important source of protein in the human diet and a real source of income for producers. However, fish farming is still less well known among the Ivorian population, and does not yet benefit from technical assistance. This could have an impact on the quality of aquaculture resources. This study was therefore carried out firstly to assess the current state of fish farming in the Haut-Sassandra region, and then to evaluate contamination by potential bacterial pathogens of tilapia fish from fish ponds in this region. To this end, a survey was carried out from June to December 2022 using questionnaires. The survey consisted of direct interviews and farm visits to collect data. Tilapia fish were then sampled and analyzed. It emerged that fish farming is a fast-growing activity in the Haut-Sassandra region, but is practiced in a related way. It is mostly practiced by people aged between 35 and 50, most of whom have a primary education. Females account for 2.66%. The dominant system is extensive, practiced in dam and diversion ponds where several activities coexist. In this region, 100% Tilapia (Oreochromis niloticus), 21% Cameroon (Heterotis niloticus) and 48% Catfish (Clarias gariepinus) are found on all farms. Of the two pond types, the barrage ponds had the best characteristics. Microbiological analyses revealed the presence of potentially pathogenic species, notably Escherichia coli, Staphylococcus aureus Salmonella spp and Enterococcus in tilapia from these fish ponds. Fish farming is a fast-growing activity, but it needs special attention to meet the needs of the Ivorian population.

Multi-omics analysis revealed the dysfunction of ovary and testis induced by chronic hypoxia in Pelteobagrus fulvidraco

Hypoxia is a global problem that not only impairs parental fish reproductive functions and fertility but can also decrease offspring fertility through the transgenerational effect, further resulting in the degradation of fish germplasm resources in aquaculture. However, an in-depth exploration of the comprehensive mechanisms of hypoxia-induced gonadal impairment in teleosts is lacking. In this study, the juvenile yellow catfish (Pelteobagrus fulvidraco) were continuously exposed to hypoxic conditions (1.9 ± 0.3 mg/L dissolved oxygen) for one month. The transcriptome, proteome, and metabolome were integrated to study the gonadal response to hypoxia in yellow catfish comprehensively. Hypoxia altered gonadal biological processes involved in angiogenesis, energy metabolism, apoptosis, and steroidogenesis. The testes and ovaries exhibited different adaptive mechanisms in response to chronic hypoxia. Angiogenesis was activated in the testes to increase oxygen delivery. Angiogenesis was inhibited in the ovaries when ovarian hemoglobin levels increased. Activated glycolysis and catabolism of glycogenic amino acids were observed in the testes. The energy metabolism in the ovaries was disrupted by hypoxia, as reflected by disordered glycolysis and suppressed synthesis of amino acids and fatty acids. Gonadal dysfunction and suppression of germ cell development by hypoxia were observed. The decrease in synaptonemal complex protein 1 (SYCP1), SYCP3, Piwi like RNA-mediated gene silencing 2 (PIWIL2), and Nanos C2HC-type zinc finger 3 (Nanos3) in the testes reflected suppressed meiosis and spermatogenesis. The downregulation of vitellogenin 1 (VTG1), zona pellucida (ZP), growth differentiation factor 9 (GDF9), inhibin subunit beta B (Inhbb), and insulin-like growth factor (IGF) signaling inhibited folliculogenesis and vitellogenesis in the ovaries. Our results provide insight into the molecular mechanisms underlying hypoxia-induced reproductive impairment in teleosts.

The relationship between business strategy and internal control in aquaculture firms

Any company that wants to achieve both financial and non-financial performance needs to have internal controls. Internal controls are intended to reduce risks, safeguard resources, guarantee accurate financial reporting, boost productivity, and ease compliance (Bashaija, 2022). The purpose of this study is to investigate how internal control and business strategy interact in Vietnamese aquaculture companies. To gather information, a survey of 225 workers in Vietnamese aquaculture companies was done. Through qualitative and quantitative methodologies, we used Cronbach’s alpha, exploratory factor analysis (EFA), and regression analysis to determine the relationship between business strategy and internal control. The results showed that the business strategy had a positive relationship with internal control. In particular, the defensive strategy is the strongest. From the findings, this study suggests several recommendations to improve internal control, such as improving business strategy. The findings are thought to be a helpful resource for Vietnamese aquaculture companies looking to move toward sustainable development.

Assessing impacts of coastal warming, acidification, and deoxygenation on Pacific oyster (Crassostrea gigas) farming: a case study in the Hinase area, Okayama Prefecture, and Shizugawa Bay, Miyagi Prefecture, Japan

Abstract. Coastal warming, acidification, and deoxygenation are progressing primarily due to the increase in anthropogenic CO2. Coastal acidification has been reported to have effects that are anticipated to become more severe as acidification progresses, including inhibiting the formation of shells of calcifying organisms such as shellfish, which include Pacific oysters (Crassostrea gigas), one of the most important aquaculture resources in Japan. Moreover, there is concern regarding the combined impacts of coastal warming, acidification, and deoxygenation on Pacific oysters. However, spatiotemporal variations in acidification and deoxygenation indicators such as pH, the aragonite saturation state (Ωarag), and dissolved oxygen have not been observed and projected in oceanic Pacific oyster farms in Japan. To assess the present impacts and project future impacts of coastal warming, acidification, and deoxygenation on Pacific oysters, we performed continuous in situ monitoring, numerical modeling, and microscopic examination of Pacific oyster larvae in the Hinase area of Okayama Prefecture and Shizugawa Bay in Miyagi Prefecture, Japan, both of which are famous for their Pacific oyster farms. Our monitoring results first found Ωarag values lower than the critical level of acidification for Pacific oyster larvae in Hinase, although no impact of acidification on larvae was identified by microscopic examination. Our modeling results suggest that Pacific oyster larvae are anticipated to be affected more seriously by the combined impacts of coastal warming and acidification, with lower pH and Ωarag values and a prolonged spawning period, which may shorten the oyster shipping period and lower the quality of oysters.

Development and Application of an Integrated System for the Detection and Prediction of Harmful Algal Blooms in Korea

Harmful algal blooms (HABs) are types of phytoplankton overgrowth that adversely affect marine ecosystems and aquaculture resources. One such HAB species, Cochlodinium polykrikoides, occurs irregularly and causes significant damage to the aquaculture industry along the coastal regions of Korea. In this study, we developed and implemented an integrated system to detect and predict HAB occurrences in real time. This system comprises four main components: (1) a real-time detection system utilizing acoustic sensing, ocean weather, water temperature, salinity, and chlorophyll, satellite images, genetic analysis, and optics; (2) a prediction model system based on current and tidal, HAB occurrence, and HAB movement and diffusion models; (3) an additional data based on HAB information of sampling data and HAB information of GPS data, and (4) an integrated information system utilizing data storage servers and a visualization platform. We applied and assessed the efficiency of this integrated system in the South Sea of Korea from 2017 to 2019. Particularly, HABs occurred significantly in 2019, and the system demonstrated the feasibility of detection and prediction under field conditions. Implementing a more advanced integrated detection and prediction system in the field is anticipated to minimize the damage caused by irregular HAB occurrences every year.

Cryopreservation effect on DNA methylation profile in rainbow trout spermatozoa

Spermatozoa are the cells that are most commonly used for cryopreservation of valuable genetic resources in aquaculture. It is known that fish spermatozoa transmit to the embryo not only their genetic but also their epigenetic profile, especially DNA methylation. Therefore, any alteration of the DNA methylation profile in spermatozoa induces the risk of transmitting epigenetic alterations to the offspring. The aim of this study was to assess the effect of cryopreservation on DNA methylation in rainbow trout spermatozoa. To trigger variable cellular response after freezing–thawing, spermatozoa from mature males were cryopreserved with dimethyl sulfoxide, methanol or glycerol as cryoprotectant. We observed that dimethyl sulfoxide was the best to preserve thawed spermatozoa functions. Methanol only slightly preserved all the cellular parameters, while glycerol failed to protect motility and fertilization ability. The consequences on DNA methylation were assessed using Reduced Representation Bisulfite Sequencing (RRBS). Sperm cryopreservation did not thoroughly impact DNA methylation, although 335–564 differentially methylated cytosines were characterized depending on the cryoprotectant. Very few of them were shared between cryoprotectants, and no correlation with the extent of cellular damage was found. Our study showed that DNA methylation was only slightly altered after sperm cryopreservation, and this may render further analysis of the risk for the progeny very challenging.

Sustainability level of the pearl lobster (Panulirus ornatus) aquaculture business using the systems of floating-net cage and fixed-net cage: A case study in South Sulawesi Province, Indonesia

Marine aquaculture is currently the fastest-growing seafood industry globally, offering a potential solution to overfishing problems, while enhancing food security and income generation. South Sulawesi, a province in Indonesia, is rich in aquaculture resources, one of which is lobster. The two commonly used aquaculture systems are the floating-net cage (KJA) and fixed-net cage (KJD). The growing market demand and rising lobster prices pose a threat to resource sustainability due to overexploitation. This is issue have to be addressed to achieve sustainable fishery development. Sustainability is the primary focus on global fishery development. According to the United Nations, sustainable development encompasses three dimensions: the economy, social and ecology. Therefore, sustainable fishery, particularly aquaculture, relies on obtaining significant benefits while minimizing environmental damage. Hence, this study aimed to analyze the sustainability level of the pearl lobster (Panulirus ornatus) aquaculture in South Sulawesi, based on the provided background information. The study included a sample of 62 farmers. The sample selection involved the use of the stratified sampling method, with 51 farmers from (KJA) and 11 farmers from (KJD). The sustainability analysis, conducted through assessment of based farmers’ perceptions, served as the analytical method. The findings revealed that pearl lobster (Panulirus ornatus) aquaculture has a medium level of sustainability. Employing Integrated Multi Tropic Aquaculture (IMTA) and Regional Integrated Multi Tropic Aquaculture (RIMTA) techniques is a recommended sustainability level.

Transcriptome analysis reveals the molecular mechanisms of heterosis on thermal resistance in hybrid tilapia (Oreochromi niloticus ♀×Oreochromi aureus ♂)

Heterosis is a widely observed biological phenomenon in fishes, in which hybrids exhibit superior traits to their parents. However, the underlying molecular mechanisms for heterosis are not well understood. Tilapia is an economically important aquaculture resource with high commercial value, and the phenomenon of high temperature tolerance in hybrid tilapia (Oreochromis niloticus ♀ × Oreochromis aureus ♂, AN) has been observed in recent studies. Uncovering the molecular mechanisms underlying this phenomenon could provide theoretical support for heterosis in thermal tolerance. To investigate the gene expression patterns and alternative splicing events associated with heat stress in tilapia, RNA Sequencing was conducted at control temperature (28 °C) and heat stress temperatures (36 °C and 39 °C). A total of 280, 260, and 261 genes with significantly divergent alternative splicing events were identified in O.niloticus (NL), O.aureus (AR), and O. niloticus ♀ × O.aureus ♂ (AN), respectively. In the heat stress groups (39 °C groups), 83.59% (23779 out of 28446) of the expressed genes showed non-additive expression patterns, and the highest proportion (35.14%) of these genes exhibited over-dominance expression patterns. KEGG pathway enrichment analysis showed that the overlapping genes among common differentially expressed genes (DEGs) and non-additively expressed genes (NAGs) were significantly enriched in apoptosis, adipocytokine signaling, and insulin signaling pathways. Furthermore, among these overlapping genes, 32 genes had undergone alternative splicing events in AN, which may play an important role in the thermal resistance of hybrid tilapia. These findings shed light on the physiological regulation mechanisms that allow hybrid tilapia to exhibit better thermal resistance than their parents. They provide important insights into the molecular basis of heterosis in tilapia and have potential implications for improving aquaculture practices.