Aquaculture, Fish and Fisheries最新文献

Sea cucumber ranching has been proposed as a sustainable, low-trophic source of seafood while remediating organic aquaculture waste. This exploratory study investigates the bioaccumulation and depuration of two finfish veterinary therapeutants, emamectin benzoate (EB) and oxytetracycline (OTC), in the European black sea cucumber (Holothuria forskali) within controlled conditions. Sea cucumbers (n = 80) were fed medicated aquafeed for 7 days, followed by tissue sampling at intervals up to 33 days. Mean initial tissue concentrations were 12.18 ± 0.99 ng/g for EB and 3.45 ± 2.90 µg/g for OTC. The elimination half-lives (t_1/2) were 10.7 days for EB and 23.1 days for OTC. Notably, 78% of sea cucumbers eviscerated their internal organs after exposure, and seven mortalities occurred. The sampled control animals (n = 20) were intact, indicating potential physiological stress from ingesting therapeutants. This exploratory study provides critical initial data on therapeutant impacts after ingestion by H. forskali, highlighting the need for further field validation to establish appropriate withdrawal periods for sea cucumber ranching within aquaculture systems using veterinary therapeutants.

The Nannochloropsis oceanica microalgae contain a high content of polyunsaturated fatty acids, amino acids, and proteins, which are essential in diets intended for the cultivation of mollusks, crustaceans, and fish to ensure good larval growth and better survival. Counting any microalgae is fundamental to maintaining the good health of mollusks and other species that base their diet on this organism. Currently, in different aquaponics processes, counting is done manually, which is tedious for the technician and prone to errors. This study proposes an automatic counting system based on computer vision and machine learning. We describe the development of two applications. The first one allows the technician to manually count the microalgae, marking them manually to build a microalgae dataset. Once we generated the dataset, we trained classical machine learning models and compared them against a convolutional neural network (CNN). Finally, we integrated these models into a second desktop application in which the technician selects the region of interest within the microscopy image, and the app counts the microalgae based on the previously trained models. We report 91% accuracy in the CNN-based model we trained, which is an adequate percentage given the noise and variable lighting conditions of the microalgae dataset.

Protein sparing is an established practice in feed manufacturing where relatively inexpensive ingredients, such as lipids, are incorporated to reduce or ‘spare’ expensive protein ingredients. In this 84-day study, Yellowtail Kingfish, Seriola lalandi (2.13 ± 0.23 kg, mean body mass ± SD; 504 ± 19 mm, fork length ± SD), were fed six different diets formulated on a digestible basis that contained highly palatable and digestible ingredients at realistic commercial inclusion levels to evaluate lipid digestion and storage. Diets were formulated to graded crude protein (CP) levels (40%, 44% and 48%) and either 25% or 30% crude lipid (CL). Lipid and glycogen storage were not significantly affected by CP or CL level. However, a negative relationship between increased CP and hepatocyte vacuolisation was indicated. Crude protein did not influence the bile acid concentrations in digestive tissues, whereas diets with a 30% CL level decreased the total bile acid concentration of gallbladder content compared to that of fish fed diets with a 25% CL level, but no other digestive parameters were affected. Fish fed a dietary CL level of 25% had elevated taurine concentrations in the liver compared with fish fed diets containing a 30% CL level. Liver 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) concentration of fish fed diets containing 40% CP level was reduced compared to fish fed diets containing 48% CP levels. Total bilirubin of fish fed 48% CP was less than that of fish fed 44% CP but not fish fed 40% CP, which was similar to that of fish fed both 44% CP and 48% CP. At the water temperatures recorded in this study, Yellowtail Kingfish can be fed diets with up to 30% CL and 48% CP without affecting total bile acid synthesis, storage and liver lipid storage.

In Brazil, a large quantity of shrimps captured through commercial fishing is marketed as labelled frozen packages following current legislation (Normative Instruction No. 23, of 20 August 2019). This study tested the possibility of errors in species identification (forensic analysis) listed on the labels of packages sold in the country by using mitochondrial molecular marker. Labelled samples (packages) were acquired in supermarkets in different states of Brazil, and specimens were selected on the basis of apparent morphological differences for analysis. DNA was extracted from each specimen selected from packages, with 16S marker amplification, DNA purification and sequencing. Generated sequences were compared with those available in GenBank using BLAST and grouped by neighbour-joining method. Mislabelling was detected regarding species identification. Specimens of Pleoticus muelleri (Solenoceridae) were labelled as ‘pink shrimp’, which should be some species from the genus Penaeus (Penaeidae). Furthermore, representatives of Artemesia longinaris and P. muelleri were found under the label ‘seabob shrimp’ (i.e., Xiphopenaeus spp.). On the other hand, most of the samples were in accordance with the regulations regarding species identification. Our results indicated that some packages (8.8%) do not comply with the regulations. This finding means lack of precision about what is being commercialized and suggests the necessity to propose adjustments in-line with consumer rights and species conservation.

This study evaluates the performance of an integrated aquaponic system combining gravel bed and NFT modules within a recirculating loop, focusing on nutrient dynamics, plant growth and sensory quality. Conducted in a semi-controlled greenhouse, the system utilized Nile tilapia (Oreochromis niloticus) and cultivated lettuce, Swiss chard and pepper. Water quality analysis showed reduced nitrate levels after the NFT module (0.792 mg/L) compared to source RAS water (1.04 mg/L), while the gravel bed demonstrated superior phosphate removal (0.052 mg/L) and the lowest ammonia concentration (0.074 mg/L). Lettuce grown in NFT exhibited significantly greater shoot biomass (187.00 ± 15.53 g) than gravel-grown plants (105.33 ± 11.79 g), with similar differences observed in root biomass. Plant performance was significantly influenced by the cultivation system, plant variety and their interaction. Pepper plants in NFT produced more fruits (9.00 ± 1.47 vs. 5.50 ± 0.96) and longer fruits, while gravel-grown fruits had ∼8% greater average mass, although this difference was not statistically significant. Sensory evaluation indicated a general preference for NFT-grown lettuce in appearance, aroma, texture, flavour and overall acceptability, though these differences were not statistically significant. Economically, the NFT system yielded higher returns and lower media costs, resulting in a net financial benefit of 11,804.52 ETB. Overall, the NFT system outperformed the gravel bed in plant productivity, nutrient efficiency and economic viability, while gravel beds may offer advantages in contexts requiring greater phosphate or ammonia retention.

Genetic selection for carcass traits has always presented difficulties, because it is necessary to slaughter the animals to collect direct measurements of these traits. So, we evaluate, by path analysis, the cause-and-effect relationship between morphometric measurements and carcass traits on pacu Piaractus mesopotamicus, a very important species for aquaculture in Latin America. A total of 120 fish, at different ages, were anaesthetized, measured in standard length (SL), head length (HL), body height (BH) and body width (BW), slaughtered and processed to obtain the weights and yields of carcass, head, fillet, rib and residue. Path analysis was employed to estimate direct and indirect effects, with body part weight and yields as dependent variables and morphometric measurements and relationships as explanatory variables. Body and rib weights, as well as head yield, are strongly influenced by morphometric variables; HL/BH ration and SL can be used efficiently to determine and indirectly select these traits. With less efficiency, it is possible to indirectly select animals with higher weights and fillet yields and lower residual weights using BH, BW and SL, respectively.

The cover image is based on the Original Article by Evaluation of Nutrient Flow Through and Media-Bed Aquaponic Systems by Belay Abdissa et al., https://doi.org/10.1002/aff2.70122.

The three key processes in the breeding of redclaw crayfish are nutrient enhancement by parents, catching and hatching of egg-holding crayfish and maintaining a feed supply for juveniles. An appropriate combination of green ecological additives is beneficial for improving the production efficiencies of the three key processes. Three experiments were conducted. Experiment 1: Five additive combinations were added to the feed of the parents. The results showed that adding 30% special feed powder (25% methyl farnesyl ester + 10% schizonts powder + 10% purple algae powder + 5% serotonin creatinine sulphate + 7.5% flaxseed oil + 7.5% alanine hydroxamic acid) to the feed was beneficial for improving the egg-holding effect of crayfish. Experiment 2: The application of a mixed ecological preparation composed mainly of eugenol for the anaesthesia and disinfection of red crayfish was investigated. The results showed that 400 mg/L eugenol + 10 mg/L cinnamaldehyde + 50 ppm acacia essential oil + 60 mmol/L trehalose + 4 ppm vitamin C + 2 ppm vitamin A + 2 ppm vitamin E had good anaesthetic and disinfectant effects, reducing the loss of eggs caused by stress-induced tail bouncing during the grasping process and achieving a high hatching and survival rate of juveniles, and high activity of antioxidant and immune-related enzymes. Experiment 3: Six additive combinations were added to the feed of the juveniles. We speculated that adding 10% spirulina powder + 3% astaxanthin + 2% flaxseed oil + 3% Antarctic krill oil + 2% riboflavin to the feed improved the survival rate, growth rate and digestive enzyme activity of juveniles. We recommended that these three combinations of green ecological additives be widely applied in the breeding of redclaw crayfish.

Red tilapia is an increasingly important aquaculture species due to its rapid growth and high consumer preference. However, variation in pigmentation, particularly blotched phenotypes, reduces market value and uniformity of fingerlings. This study assessed the effects of broodstock pigmentation phenotype on progeny survival, growth performance, reproductive success and pigmentation inheritance. Four broodstock cross combinations were established: Cross A (plain red × plain red), Cross B (blotched male × plain red female), Cross C (blotched × blotched) and Cross D (plain red male × blotched female). Broodstocks were stocked in hapas and reared under standardised conditions in a ratio of 1 male to 3 females. Each treatment group was done in triplicate hapas. Data were collected on hatching success, survival, growth performance and pigmentation phenotype distribution. Survival, hatching success and growth performance did not differ significantly amongst the four crosses (p > 0.05), with survival averaging 85.6%–86.9% and weight gains 7.1–7.4 g. In contrast, pigmentation segregation showed significant differences (p < 0.05). Cross A produced significantly higher plain red progeny (94.6% [18.2:1 ratio]), while Cross C recorded markedly higher blotched offspring (73.4% [1:2.7 ratio]). Crosses B and D yielded intermediate distributions (40%–43% blotched; 1.3–1.4:1 ratio). Maternal versus paternal blotched origin did not significantly alter body pigmentation outcomes. The study concludes that pigmentation inheritance in red tilapia is heritable and consistent with a polygenic model with major-effect alleles. Plain red male × plain red female crosses are the most effective for producing uniform progeny with high market value. Hatchery managers are advised to prioritise plain red broodstock and avoid blotched parents when the goal is consistent pigmentation. Future research should integrate molecular tools to refine selective breeding strategies and strengthen sustainable seed production systems.

Maternally inherited transcripts are crucial for the developmental competence of salmon embryos. Due to the wide variety of broodstock conditioning approaches used in commercial aquaculture, there is a need to understand how dynamic commercial environments impact the egg transcriptome and subsequent quality. In this study, the transcriptomic profile of eggs was dependent on the broodstock conditioning approach, with 156 isoforms significantly down-regulated and 105 significantly up-regulated in the flow-through (FT) relative to the recirculating aquaculture system (RAS)-based group. In FT-based eggs, a down-regulation of genes related to survival (CCCTC-binding factor), growth (DEAH (Asp-Glu-Ala-His) box polypeptide 33), left-right pattern development (Protein canopy-1), and yolk hydrolysis (Cathepsin B) was observed, whereas up-regulation was observed for genes related to bone and tissue development (Metalloproteinase inhibitor 2) and energy production (Cytochrome c oxidase II, mitochondrial). Subsequent embryo quality (neural streak development, embryo survival, and developmental progression) was apparently lower in the FT-based group. As such, there is evidence to suggest that routine husbandry approaches (and associated differences in water quality) have a significant impact on egg quality, and this is underpinned, at least in part, by changes in the maternally inherited transcriptome.