The current study is a new approach for investigating the ameliorative effects of chia seeds powder (CSP) ( Salvia hispanica ) against haemato‐biochemical dysfunction, oxidative stress, and DNA damage induced by zinc oxide nanoparticles (ZnONPs) in Oreochromis niloticus . Four fish groups were allocated in triplicates as follows: group I‐control, group II‐treated with 10 g/kg diet CSP, group III‐exposed to 1/20 LC 50 of ZnONPs, and group IV‐exposed to 1/20 LC 50 of ZnONPs + 10 g CSP/kg diet for 30 days. Blood, liver, and kidney tissue samples were collected at the end of the experiment for haemato‐biochemical, oxidative stress biomarkers, and DNA damage evaluations. Results revealed that CSP administration significantly ameliorated the ZnONPs toxic effect. Where, CSP effectively increased WBCs, and serum total proteins, albumin, globulin, and immune parameters (IgG, IGM, and lysozyme [LYZ] activity), which were decreased after exposure to ZnONPs toxicity. In addition to the prominent ability of CSP to decrease the elevated levels of stress indicators (glucose and cortisol), liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), kidney products (creatinine and urea), catalase (CAT), superoxide dismutase (SOD), and hepato–renal lipid peroxidation (LPO) of Nile tilapia exposed to ZnONPs. Furthermore, CSP sustained the activity of the reduced glutathione (GSH), total antioxidant capacity (TAC), and WBCs, Hb, and Ht content were significantly declined in ZnONPs‐exposed O. niloticus compared to the control group. Meanwhile, administration of 10 g CSP/kg diet restored the hemato‐biochemical profile and reduced oxidative damage induced by ZnONPs toxicity as the WBCs and hepatic DNA damage were significantly increased in exposed fish. The study suggested that CSP treatment has hepato‐renal protective functions and antioxidative effect against ZnONPs toxicity in Nile tilapia.

Significant growth heterogeneity is prevalent in farmed Japanese eels ( Anguilla japonica ), whereas its underlying causes remain poorly understood. The study investigated the metabolic, digestive, and behavioral phenotypic differences between fast‐ and slow‐growing A. japonica . A total of 100 elvers (22.88 ± 1.11 g) were randomly allocated into four net cages (25 individuals per cage). After 8 weeks of rearing, the three heaviest and three lightest individuals from each cage were selected and designated as fast‐growing eel (FGE) and slow‐growing eel (SGE), respectively. Plasma metabolic profiling revealed that SGE showed significantly lower levels of total cholesterol (TC), low‐density lipoprotein cholesterol (LDL‐C) and lactate compared to FGE, while aspartate aminotransferase (AST) was higher ( p < 0.05). Moreover, oxygen consumption rate (OR) and ammonia excretion rate (AR) in SGE were significantly higher than FGE. Significant differences in digestive and metabolic enzyme activities were observed, with SGE displaying lower amylase, trypsin, Na + ‐K + ‐ATPase, and ATPase levels than FGE ( p < 0.05). In behavioral phenotypes, SGE exhibited a longer latency time, along with reduced total feed intake and amount of feces than FGE, while no significant differences in relative feed intake or relative amount of feces. Additionally, compared to FGE, the expression levels of neuropeptide Y ( npy ) and ghrelin were significantly downregulated in SGE, whereas corticotropin‐releasing hormone ( crh ) mRNA upregulated ( p < 0.05). Multivariate analysis identified that AST and crh may serve as primary discriminators for SGE classification. In conclusion, the differences in feeding behavior, metabolic level, and digestive capacity were related to growth disparity between individual eels. These findings advanced our mechanistic understanding of growth variation in A. japonica and provided valuable insights for promoting uniform growth.

Two additives, rosemary oil and a commercial herbal product (HP; AROTEC‐G) containing garlic essential oil, carvacrol and thymol were investigated for their potential to reduce the parasitic burden in yellowtail kingfish (YTK; Seriola lalandi) infected with Zeuxapta seriolae. Naturally infected fish were fed diets supplemented with either 2.5 mL.kg−1 rosemary oil or two concentrations of HP (5 and 10 g.kg−1) for 20 days. At 10 and 20 days, the effect of the diets on parasite abundance was evaluated. Feed intake and growth were similar across treatments (p > 0.05). By day 10, both rosemary oil and HP significantly reduced parasite burden compared to the control (p = 0.03). Praziquantel (PZQ) baths on days 10 and 20 found that the supplements were more effective in reducing new parasite recruitment rather than eliminating adult parasites. The HP product, at both doses, significantly reduced reinfection by day 20. Rosemary oil reduced parasite load by 43% compared to the control by day 20. Liver and kidney function remained unaffected. This study concluded that rosemary oil and blended essential oils can assist in the management of Z. seriolae infection in YTK culture.

Aquatic organisms experience oxidative stress due to environmental stressors that promote oxygen exchange, such as eutrophication, algal photosynthetic activity, or changes in water temperature. This study aimed to clarify the effects of oxidative stress on the liver of juvenile rainbow trout (Oncorhynchus mykiss) exposed to hypoxia and hyperoxia by examining the physiological roles of hydrogen peroxide, glutathione (GSH) redox status, malondialdehyde (MDA) concentration, antioxidant enzyme activity, and antioxidant gene expressions. Dissolved oxygen levels were maintained at 4.0 ± 0.5 mg/L for hypoxia, 7.5 ± 0.5 mg/L for normoxia, and 12 ± 1.2 mg/L for hyperoxia. Liver samples were collected from each experimental group following exposure (6, 12, 24, 48, and 72 h) and chronic exposure (28 days). Under both hypoxia and hyperoxia conditions, reduced GSH levels and the oxidative stress index (OSI) decreased compared to normoxia (control group), whereas oxidized glutathione (GSSG) levels, the GSH/GSSG ratio, and MDA concentrations increased. Hydrogen peroxide levels were unstable. Superoxide dismutase (SOD) activity remained consistently lower than that of the control group. Catalase (CAT) activity decreased with chronic exposure to hyperoxia. Glutathione peroxidase (GPx) activity fluctuated with varying oxygen treatments. Glutathione‐S‐transferase (GST) activity increased after 12 h of hypoxia exposure but decreased with acute hyperoxia; however, chronic hyperoxia exposure eventually increased GST activity. Glutathione reductase (GR) activity is generally reduced under hypoxia. The expressions of SOD and CAT increased at 24 h but decreased at other times. GPx expression increased under chronic hypoxia but decreased under hyperoxia, while GST expression decreased with chronic treatments. Hypoxia and hyperoxia influence the antioxidant defense system in the fish liver through different pathways. While a coordinated relationship between gene expression and enzyme activities is observed under acute exposures, this coordination diminishes during chronic exposures, leading to the depletion of defense mechanisms. This suggests that the capacity of aquatic organisms to adapt to oxidative stress is limited and that post‐transcriptional mechanisms play a significant role in regulating antioxidant responses.

Aquaculture techniques for marine ornamental fish have advanced rapidly but remain in their early stages, with challenges in providing suitable food for larvae. This study investigated using inorganic fertilization to raise Cirrhitichthys falco larvae. The fertilized group (F group) received inorganic nitrogen and phosphorus (N: 700 µg L−1, P: 100 µg L−1) without supplemental feeding, while the control group (C group) was fed the ciliate Euplotes sp. without fertilization. Key measurements included nutrients, water conditions, chlorophyl a, zooplankton density and diversity, and larval survival. Results showed higher phosphorus, nitrogen, dissolved oxygen (DO), pH, chlorophyl a, and zooplankton density in the F group (p < 0.05), with zooplankton mainly composed of Strombidium spp. The F group also had significantly higher larval survival rates and growth compared to the C group (p < 0.05). This suggests that inorganic fertilization stimulates natural prey production, enhancing survival and growth, and reducing the need for specific feeding strategies in marine fish larviculture.

Inappropriate use of antibiotics in aquaculture, livestock, and agriculture contributes significantly in the development of antimicrobial resistance. This study assessed antimicrobial residues and heavy metals in fish, water, and sediments within Nairobi County, Kenya. Eighteen (18) fish farms were visited and water (17), fish (11), and sediment (9) samples were collected. The samples were analyzed using liquid chromatography coupled with tandem double mass spectrometry (LC‐MS/MS) and ICP‐MS for antimicrobial residues and heavy metals, respectively. Thirteen (13) antimicrobial residues: trimethoprim, sulfadiazine, sulfamethoxazole, sulfamethazine, tetracycline, doxycycline, oxytetracycline, erythromycin, azithromycin, ampicillin, penicillin G, amoxicillin, and cloxacillin tested were detected in all three sample types at concentrations below the recommended maximum residue levels. The overall percentage of tetracylines, sulfonamides, trimethoprim, beta‐lactams, and macrolides antibiotic residues classes positive in water, fish, and sediment samples were (94.12%, 100%, 100%), (94.12%, 100%, 100%), (100%, 100%, 100%), (35.29%, 9.09%, 33.33%), and (94.12%, 0%, 11.11%), respectively. The mean tetracylines, sulfonamides, trimethoprim, beta‐lactams, and macrolides antibiotic residues classes concentrations in water, fish, and sediment samples were (2.38 ± 5.687, 5.04 ± 2.116, 17.81 ± 21.782 ppb), (0.19 ± 0.124, 1.83 ± 3.641, 3.26 ± 1.434 ppb), (0.68 ± 0.503, 1.80 ± 1.679, 14.46 ± 10.638 ppb), (0.25 ± 0.263, 1.80 ± 1.679, 2.26 ± 2.25 ppb), and (0.76 ± 0.719 ppb, <LOD, 0.05 ± 0 ppb), respectively. Heavy metals mean concentrations for chromium (Cr), lead (Pb), arsenic (As), and cadmium (Cd) in water, fish, and sediment samples (0.05 ± 0.08, 0.73 ± 0.60, 2.69 ± 1.06 mg/kg), (0.003 ± 0.002, 0.14 ± 0.11 , 3.51 ± 2.61 mg/kg), (<LOD, 0.001 ± 0, 0.45 ± 0.17 mg/kg), and (<LOD, <LOD, 0.02 ± 0.02 mg/kg). Mercury (Hg) tested negative for all the samples analyzed. All fish samples tested had Cr concentrations exceeding the set maximum residue limit (MRL) of 0.05 mg/kg in fish muscle according to European Commission regulation 2016. Sediments recorded the highest concentrations, followed by fish and water, for both heavy metals and antimicrobial residues. Levels of heavy metals detected in fish were not associated with noncarcinogenic risks. However, Pb and Cr levels detected in the fish tissues were noted to pose carcinogenic health risks and, therefore, threatens the public health safety of fish consumption in this area of study.

To explore the effects of temperature on the reproductive performance and embryonic development of female Eriocheir sinensis broodstock, the reproduction experiments of broodstock crabs under different temperatures (6, 9, 12, 15, 18, and 21°C) were carried out. Each temperature was replicated in three parallel tanks, with 5 male and 10 female crabs stocked in each tank for feeding. The results showed that with the rising of temperature, the mating rate of broodstock crabs increased gradually, the spawning rate, spawning amount, fecundity and reproductive index increased first and then decreased. At 15°C, the spawning rate, spawning amount, fecundity and reproductive index of the broodstock reached the highest and significantly higher than other temperature groups (p < 0.05). At 18°C, the egg diameter of embryos reached the largest. At 18°C, the contents of crude protein, triglyceride (TG) and total cholesterol (CHL) of embryos in E. sinensis were the highest. With the rising of temperature, the embryonic development rate of E. sinensis accelerated, the embryonic development time of the crabs was shortened and the effective cumulative temperature was gradually decreased. At 6°C, embryos stagnate at the fertilized egg stage, while at 9°C, they develop to the multicell stage but cease division thereafter. In conclusion, the best reproductive performance of the Chinese mitten crab was achieved at 15°C and the quality of embryos produced at 18°C was relatively good. The results of this study not only provided basic data for the breeding biology of E. sinensis but also provided scientific support for the conservation of fishery resources in the Yangtze River Estuary.

Aquaponics and biofloc‐based aquaculture systems are environmentally sustainable food production systems. When biofloc technology is combined with hydroponic systems, it expands economic diversity by producing additional value‐added products. Dietary additives were incorporated into fish feeds in this trial to improve food production in decoupled aquaponic systems. In this decoupled aquaponic system, the biofloc aquaculture system consisted of nine cylindrical tanks of 3750 L with 170 juvenile Nile tilapia (9.99 ± 0.54 g) stocked in each tank. The fish were randomly assigned to one of three treatment groups: fish fed a commercial feed (Com), commercial diet + protease complex (PC; AG175 by Jefo Nutrition; 175 g 1000 kg−1), and commercial feed + humic substance (HS; MFG50 by Kent Nutrition; 2500 g 1000 kg−1). The feeding trial was conducted for 60 days. A deep‐water culture hydroponic system with nine 109 L troughs was used. Each trough corresponded to each tank and contained 15 romaine lettuce plants. The first 4 weeks were fish growth trials, and the last four were fish and plant growth trials. Fish and plant growth parameters showed no differences between treatments. However, the leaf greenness in romaine lettuce plants in the PC treatment had significantly higher chlorophyll content than the other treatments (p = 0.002). When microbial communities were analyzed, significant differences were found in the Shannon diversity indices (fecal, water, and root p < 0.001), Chao1 (fecal p < 0.002, water p < 0.001, and root p < 0.001), and observed species (feca; p = 0.046, water p = 0.017, and root p = 0.015). When beta diversity was analyzed through the Bray–Curtis dissimilarity index, fecal samples (p = 0.001) and root samples (p = 0.002) showed clear differences. The most abundant phyla found in all samples were Pseudomonadota. Overall, this study concluded that these additives did not affect the growth of Nile tilapia and romaine lettuce but influenced the bacterial composition of fish feces, water, and root samples and the chlorophyll content of the plants.

Liaodong Bay is an important aquaculture base in the northernmost part of China’s sea area. With the rapid development of aquaculture and the rapid expansion of aquaculture ponds, the ecological environment of many aquaculture areas has been deteriorating, which has brought about a series of ecological and environmental problems, so it is necessary to carry out rapid, accurate, and sustained monitoring of the near‐coastal aquaculture areas. In this study, we utilized the Google Earth Engine (GEE) platform to extract the spatial distribution and temporal distribution information of aquaculture ponds in Liaodong Bay in a long‐term time series from 1985 to 2020 using Landsat image data, which was validated by accuracy assessment, and then analyzed the distribution, area change, and spatial and temporal evolution of aquaculture ponds. The results showed that the spatial distribution of aquaculture ponds in Liaodong Bay was uneven, with hotspots mainly located in Linghai, Jinzhou; Gaizhou, Yingkou; Suizhong, Huludao; Changxingdao, Dalian; and part of Panjin. The process of change in the area of aquaculture ponds in Liaodong Bay is divided into three phases: the fluctuation period of 1985–1995, the rapid expansion period of 1995–2010, and the stabilization period of 2010–2020, and the aquaculture ponds in Liaodong Bay show a shift from continuous expansion to sustainable development, from quantitative growth to quality and efficiency, and from single‐emphasis on production to energy‐saving and environmentally friendly modes. The results of the study are expected to reveal the current situation, dynamics and development pressure of aquaculture ponds in the coastal area of Liaodong Bay, and to provide information support and decision support for scientific planning of aquaculture in Liaodong Bay.

The study investigated how phytobiotic‐supplemented diets impact the growth performance, feed utilisation and resistance of Nile tilapia (Oreochromis niloticus) to Streptococcus agalactiae. Fish with a total mean initial mass (37.6 g) of 180 and a random stocking of 15 fingerlings per 150 L tank in triplicate were divided into four groups and fed isonitrogenous (299 g kg−1 crude protein) and isoenergetic (15.7 kJ g−1 gross energy) control diets supplemented with 1% turmeric (Curcuma longa; TUD), garlic (Allium sativum; GAD) and ginger (Zingiber officinale; GID) powder for 56 days. After the trial period, growth performance, feed utilisation and blood health were measured. Ten fish from each replicate were infected with S. agalactiae and mortality was observed for 14 days. The results showed a significantly higher weight gain (g), specific growth rate (SGR; %/day) and average daily growth (ADG; g) in GAD (80.3 ± 1.0, 2.04 ± 0.05 and 1.434 ± 0.02, respectively) and GID (77.03 ± 0.8, 2.0 ± 0.04 and 1.376 ± 0.01, respectively) compared to the control group (60.4 ± 2.5, 1.71 ± 0.02 and 1.079 ± 0.04, respectively). However, these metrics were not significantly higher in TUD (63.8 ± 2.2, 1.8 ± 0.05 and 1.139 ± 0.04, respectively) when compared to the control group. TUD, GAD and GID feed conversion ratio (FCR) and efficiency, as well as protein efficiency ratio (PER), were improved as compared to the control. The haemoglobin (HGB), haematocrit (HCT), platelets (PLTs), white blood cells (WBCs), serum biochemistry and respiratory burst activity (RBA) of TUD, GAD and GID were significantly better than the control. Lysozyme and bactericidal activities were also significantly improved in TUD, GAD and GID as compared to the control. Following the S. agalactiae infection, the fish survival rates of GAD (67.7%), GID (53.3%) and TUD (46.7%) were better than those of the control (26.3%). Dietary supplementation with the above‐mentioned phytobiotics in Nile tilapia culture can help to increase production in view of the current challenges posed by the increased incidence of disease in fish farms. They are recommended to enhance growth, immunity and resistance to disease.