Fish Weight Research Articles

Health risks of potentially toxic elements in Cyprinus carpio in the karst plateau lake, China.

Elevated potentially toxic elements (PTEs) in aquatic products could threaten the health of ordinary consumers. Levels of chromium (Cr), arsenic (As), lead (Pb), and mercury (Hg) in Cyprinus carpio in karst plateau freshwater Lake, Caohai Lake, China were quantified using inductively coupled plasma mass spectrometry (ICP-MS) and evaluated using a risk method with Monte Carlo simulation. Levelsof Cr, As, Pb, and Hg in muscle tissue were substantially lower than those in viscera. The maximum concentration of muscle-bound Cr, As, Pb, and Hg were less than the standard references set by Chinese Food Codex (GB 2762-2022). The levels of Cr, As, Pb, and Hg in muscle tissue were independent of fish weight and length. The hazard index of all investigated elements in muscle tissue wereless than one for adults and children, whereas the target hazard quotients of muscle-bound PTEs for children were higher than those for adults. Results indicated that exposure duration was the largest contributor to the hazard quotient of Cr, As, and Hg, whereas the concentration of Pb in muscle was the most sensitive factor affecting the variation in hazard quotient of Pb. There is no risk related to the normal intake of muscle-bound Cr, Pb, As and Hg with the consumption of Cyprinus carpio. A better definition of the probability distribution for exposure duration and PTEs concentration could result in a more accurate hazard quotient. © 2024 Society of Chemical Industry.

Levels and Classification of Microplastics and Their Impact on the Wellbeing of Selected Commercially Important Fish Species in Kisumu Bay, Lake Victoria.

Microplastics (MPs) are emerging pollutants of concern in aquatic ecosystems. Fish ingest MPs accidentally during normal feeding because they resemble prey or by ingesting prey that previously consumed them. Despite severe plastic pollution in Africa, some countries, including Kenya have implemented laws to curb this pollution menace. MPs have scantly been studied in African freshwaters. This study provides empirical data and describes the levels of MPs in four commercially important fish species in Lake Victoria. A total of 95 fish samples were collected from four sampling sites (inshore-offshore waters) between March and May 2022. Microscopy and Attenuated Total Reflectance Fourier Transformed Infrared (ATR-FTIR) spectroscopy methods were used to identify MPs. In this study, 62 out of 95 (65.26%) of the gastrointestinal tracts of the sampled fish contained MPs. The four species showed different proportions of detected MPs among the sampled individuals: 75.00% (Clarias gariepinus), 75.00% (Synodontis victoriae), 71.43% (Lates niloticus), and 59.26% (Oreochromis niloticus). Polystyrene (PS) and poly (perfluorobutadiene) were the main plastic polymers in the fish samples. The condition factors estimated for O. niloticus, S. victoriae, and L. niloticus were > 1 and < 1 for C. gariepinus, respectively. Positive correlations were observed between microplastic numbers and fish length and microplastic numbers and fish weight. However, the low R2 values obtained implied no strong relationship exists between these parameters. These findings provide evidence of microplastic contamination in fish in Kisumu Bay.

Insight into the effect of the ectoparasites on estimating the ontogenetic accumulation of trace and rare earth elements in fish: a case study of Mackerel icefish (Champsocephalus gunnari)

The ontogenetic bioaccumulation of trace elements in marine species is influenced by both biotic and abiotic factors, including parasitic infestation. The Mackerel icefish (Champsocephalus gunnari) plays a significant role in the Antarctic ecosystem. Yet the impact of parasites on trace element accumulation in this species remains unclear. This study aims to gain insight into the ontogenetic accumulation patterns of trace elements in C. gunnari and how parasitic infestations affect these patterns. Two ectoparasites (Eubrachiella antarctica and Notobdella nototheniae) were found on C. gunnari, but no endoparasites were detected. Concentrations of 34 elements in C. gunnari were analyzed, including essential elements (e.g., Ca, Mg, P), trace elements (e.g., As, Co, Cr, Cu, Fe, Mn, Mo, Ni, V, Zn, Li, Ti, Ba, Cd, Pb, Sr, Zr, Ga, Rb, Cs), and rare earth elements (e.g., Sc, Ce, Eu, Gd, La, Nd, Pr, Sm, Dy, Er, Yb). Major essential elements, such as magnesium (Mg, 1420-2380 μg g-1) and calcium (Ca, 436-1850 μg g-1), were significantly higher than minor elements like zinc (Zn, 19.5-29.3 μg g-1) and iron (Fe, 6.59-19.4 μg g-1) in both infested and non-infested fish. Strontium (Sr), though a non-essential element exhibited concentrations comparable to Fe of ranging from 2.45-13.6 μg g-1. Although the rare earth elements were detected, their concentrations were significantly lower, several orders of magnitude below those of the major and trace elements. Scandium (Sc, 0.06-0.27 μg g-1) was the only rare earth element comparable in magnitude to certain trace elements. Parasitic infestation altered the relationships between certain elements (e.g., P, Zn, and Dy) and fish length, as well as (e.g., Li, Co, Cu, and Sr) with fish weight. Nevertheless, all elements displayed consistent relationships with the condition factor, indicating that it remains a reliable indicator of trace element bioaccumulation in C. gunnari, even in the presence of ectoparasites.

Enhancing Aquaculture Productivity through Integrated Farming Systems: A Comparative Study of Fish-Pig and Fish-Duck Systems

Integrated farming systems involving fish-animal are of high relevance in current scenario. Studies like this asses the suitability of such systems in improving the aquaculture productivity and overall benefits to the ecosystem. It plays a crucial role in optimizing the use of small water resources in rural areas to enhance animal production. Given the potential of pig and duck manure as nutrient inputs in fish culture, a grow-out trial was conducted in a 0.1 ha earthen pond located in Elangitampatty, Kezhisenkattupatti, and Asakkattuppatti villages of Kollihills Taluk in Namakkal district, Tamil Nadu. The pond was stocked with four carp species: Catla, Rohu, Mrigal, and Grass carp in a ratio of 40:20:30:10 at a density of 7500 fish per hectare. Three treatments were employed: (1) Control (T0), where fish were fed with commercial feed, (2) Integrated fish-duck farming (T1), and (3) Integrated pig-fish farming (T2). In the control group (T0), fish were fed commercial fish feed (24% crude protein, 4 mm pellet size) at 4% of body weight, while in T1 and T2, fish received 50% of the commercial feed and were supplemented with duck and pig excreta, respectively. After an 8-month grow-out period, fish weights and total production in each group were recorded. Water quality parameters, such as pH, dissolved oxygen, free carbon dioxide, alkalinity, and hardness, were measured using standard methods (APHA, 2019). Results showed that pond fertilization with pig and duck excreta promoted the growth of algae, phytoplankton, and zooplankton, providing a natural food source for the fish. Total fish production was highest in the fish-pig integration system (T2), with a recorded yield of 4960.09 kg. Catla (Catla catla) had the highest individual species yield, with a total harvested weight of 2225.98 kg, followed by Grass carp (Ctenopharyngodon idella) at 1490.37 kg. The final average weight of Grass carp in T0, T1, and T2 was 1047 ± 13.27 g, 1151.10 ± 12.85 g, and 1490.37 ± 13.52 g, respectively. For Catla, the final average weight in T0, T1, and T2 was 910 ± 9.45 g, 960 ± 10.26 g, and 980 ± 12.20 g, respectively. Similarly, Rohu in T0, T1, and T2 weighed 850 ± 7.98 g, 900 ± 11.23 g, and 910 ± 11.16 g, respectively, while Mrigal in T0, T1, and T2 weighed 600 ± 6.04 g, 720 ± 8.50 g, and 730 ± 10.56 g, respectively. The results highlight that the fish-pig system outperformed the fish-duck system in terms of fish productivity, which may be due to the better nutrient composition in pig manure and the genetic potential of the fish species. An economic analysis revealed that the fish-pig integration system generated the highest net income (Rs. 555,353.90) and benefit-cost ratio (2.12), indicating that integrated fish-pig farming is more profitable than both fish-duck farming and the control group without integration.

Physiological traits and population dynamics of Schizothorax niger (Heckel, 1838): Insights from Dal Lake and the Jhelum River, Kashmir, Himalayan region.

This study examines the physicochemical characteristics, morphometric features, biometric growth parameters, biological indices, physiological parameters, and biochemical profiles of Schizothorax niger population. The physicochemical analysis revealed a maximum temperature of 12.93 ± 1.33°C and hardness of 156.53 ± 12.82 mg/L in Dal Lake, whereas the Jhelum River had a minimum level of 10.94 ± 1.12°C temperature and 128.31 ± 11.62 mg/L of hardness. Dal Lake had a neutral pH (7.5 ± 0.2) and lower dissolved oxygen (6.8 ± 0.4 mg/L) compared to the Jhelum River (pH 7.2 ± 0.3; dissolved oxygen 7.5 ± 0.5 mg/L). Morphometric analysis showed significant differences (p < 0.05) in fish length (Dal Lake: 18.4 ± 2.1 cm; the Jhelum River: 21.0 ± 1.8 cm) and weight (Dal Lake: 74.5 ± 9.8 g; the Jhelum River: 92.2 ± 7.4 g) between the sites. Biometric growth parameters demonstrated a positive allometric growth pattern, with Dal Lake having a steeper slope (b = 3.15) than the Jhelum River (b = 2.98). Biological indices revealed gender-based variations in the gonado-somatic index (GSI) and hepato-somatic index (HSI), with GSI being higher in Dal Lake (0.21 ± 0.02) and HSI in the Jhelum River (1.04 ± 0.09). Haematological and biochemical analyses showed significant differences in parameters such as haematocrit (Dal Lake: 29.2 ± 2.1%; the Jhelum River: 32.4 ± 1.8%), glucose (Dal Lake: 85.3 ± 5.4 mg/dL; the Jhelum River: 68.1 ± 4.2 mg/dL), and total protein (Dal Lake: 6.2 ± 0.4 g/dL; the Jhelum River: 5.8 ± 0.3 g/dL) between sites. These findings provide valuable insights into the physiological traits and population dynamics of S. niger, informing species-specific conservation strategies and ecosystem management practices.

Assessing microplastic abundances in freshwater fishes in a subtropical African reservoir

Microplastics are emerging pollutants of global concern, and their presence in the aquatic environment poses a serious risk for aquatic biota. While many studies have been conducted on the presence of microplastics in marine habitats, little research has been done in freshwater African reservoirs on microplastic pollution and their impacts on fish within the subtropical regions. To bridge this gap, the current study investigated microplastic abundances and distribution in freshwater fish within Nandoni reservoir, South Africa, across two seasons (i.e., hot–wet, cool–dry). Fish were randomly sampled using seine and gill nets from seven sites within the reservoir. In the laboratory, fish were then sorted according to taxa before dissecting them to remove the gills and the gastrointestinal tract (GIT). The organs were digested using hot hydrochloric acid and hydrogen peroxide, and the microplastics were classified according to their colours and shapes. Among the 94 fishes (i.e., 8 species) examined, microplastics were detected in 86.6% of the eight species caught. Microplastics were dominant in the gills and GIT during the cool–dry and hot–wet seasons, respectively. High microplastic abundances were found in the gills of Micropterus salmoides and the GIT of Coptodon rendalli, where fibres and the transparent colour were the most dominant. The results further showed high microplastic abundances in benthopelagic feeders highlighting that habitat influences fish consumption of microplastics whether directly or indirectly. Significant differences were observed in the feeding zone and season for all microplastic types. Microplastic sources in the reservoirs could be due to anthropogenic activities such as illegal dumping, fishing, and agriculture. Thus, there is a need for further investigation into the relation of fish weight, fish sex and body in relation to microplastic pollution. The highlighted ecological factors should be taken into consideration for future research and management actions aimed at mitigating and protecting the negative impacts of microplastic pollution on environmental and human health.

Recent data of the biology of the twaite shad, Alosa fallax returning for spawning to the Szczecin Lagoon (southern Baltic Sea)

In 2022–2023 specimens of A. fallax are recorded for the first time in approximately 17 years in Szczecin Lagoon. We collected 11 specimens of juveniles, 9 premature and mature females, and 9 premature and mature males (20.3–40.7 cm of total length, aged from 1+ to 4+). The 2+ aged fish was slightly dominated (34.5% of the whole sample). Females in the Szczecin Lagoon were ready to spawn in the age of 3+ and 4+ years, while males partly in 2+, and in the age of 3+ and 4+. Fulton’s condition factor of this fish was 0.93±0.14 and Clark’s 0.78±0.14. Analysis of correlations between the total length and individual weight of fish revealed that the growth of A. fallax was allometric (b &amp;lt; 3.0). The range of gonadosomatic index (GSI) was 0.12–26.59%, while the mean of the absolute and relative fecundity was 58,756 eggs per female and 139,650 eggs per kilogram of body weight. The obtained results indicate the occurrence of an anadromous population of Alosa fallax in the studied water areas. However, there is still a need to obtain detailed information on the population status and the biology of A. fallax in these areas in order to designate special conservation areas (SACs) for their protection, especially taking into account spawning habitats.

Effect of Spirulina Flour Addition in Feed on the Increase of Colour Brightness Nemo Fish (Premnas biaculeatus)

The nemo fish (Premnas biaculeatus) is a type of marine ornamental fish in Indonesia that is in high demand among the general public. The popularity of this fish can be attributed to several factors, one of which is the brightness of its coloration. One of the plants that can be employed as a color enhancer for ornamental fish is spirulina. Spirulina is a microalgae that has been demonstrated to enhance the brightness of fish coloration. Therefore, it is necessary to research on the effect of adding spirulina flour to feed on increasing the brightness of the color of nemo fish (Premnas biaculeatus). The method used in this research is an experimental method with a completely randomized design. This treatment was carried out with 5 treatments and 3 repetitions, namely: P0 : 0%/kg, P1 : 2%/kg, P2 : 4%/kg, P3 : 6%/kg and P4 : 8%/kg. The 5 treatments were repeated 3 times, resulting in 15 experimental units. The results of the researches carried out, it can be concluded that the addition of spirulina flour to feed on the brightness of the color of nemo fish (Premnas biaculeatus) is proven to increase the brightness of the color of nemo fish and the best treatment is p3 with a dose of 6%. The addition of spirulina flour to feed on the growth of length and absolute weight of nemo fish (Premnas biaculeatus) has a significant effect, while the survival rate has no significant effect.

Characterization of the myostatin gene in the neotropical species Piaractus mesopotamicus and the possibility of its use in genetic improvement programs.

The myostatin gene has played an important role in the genetic improvement of the main species of economic importance; however, it has not yet been described for some Neotropical fish essential for aquaculture. This study aimed to characterize the myostatin gene of pacu, Piaractus mesopotamicus, and investigate the association of a microsatellite marker in this gene with the weight of fish. The myostatin gene sequence was obtained after following a RACE-PCR strategy based on a partial mRNA sequence available in the GenBank database and the alignment of myostatin sequences from other fish species. The obtained sequence for the P. mesopotamicus gene was analyzed for short tandem repeats, and one dinucleotide was observed at the 3´untranslated region. A short tandem repeat polymorphism was verified in a wild population. Subsequently, the STR was evaluated in a test population of 232 animals in two 220m² concrete tanks at the Aquaculture Center of Unesp. Eight alleles and 22 genotype combinations were identified. A significant association was observed between microsatellite marker polymorphisms and the weight traits (WEIGHT1 and WEIGHT2). Alleles 210, 222, 226, and 230 were found to favor weight gain. In summary, this study contributes to the characterization of the myostatin gene in pacu fish and identifies an association between a STR and weight traits. Thus, this gene could be used as a target for genetic breeding using molecular strategies such as CRISPR and quantitative strategies such as marker-assisted selection, which would contribute to improving the production of the species.

Vertebral deformities in cultured big size Rainbow Trout: Radiological analysis from juvenile to harvest size

Vertebral deformities are a big challenge in Rainbow Trout seawater aquaculture. However, supportive scientific literature is missing. The present study used radiology to follow the development of vertebral deformities in a population of farmed Rainbow Trout as they grew from 36 g to 5.5 kg. In addition, separately collected deformity screening data from three other farmed populations were included for comparison.The fish developed deformities in different vertebral regions over time, eventuating to affect almost the entire vertebral column. At this point, the fish were ∼ 5.5 kg and 93 % of the fish had one or more deformed vertebrae. A negative relationship between severity of deformity (number of deformed vertebrae per individual), and fish length and weight strongly suggest a negative impact on fish welfare. The most frequently affected area was the ural region of the vertebral column. This region is a part of the caudal fin complex which also suffered from degradation of the fin rays. Ural region deformities were also frequent in the separately investigated populations.The current results indicate that Rainbow Trout are not able to maintain normal bone development under current farming conditions, consequently, jeopardizing the welfare of the fish.

Design and Construction of an Arduino-Driven Weight-Based Fish Sorting Tool

This research aims to design and develop a weight-based fish sorting tool that uses a strain gauge sensor under Arduino Uno control. We designed this tool to enhance the effectiveness and accuracy of the fish sorting process, focusing on three size categories: small, medium, and large. The system consists of a strain gauge sensor that measures the weight of the fish, an HX711 module that converts analog data to digital, a servo motor to move the fish, and a conveyor that moves the fish through the sorting process. We conducted testing to measure the accuracy of the system in determining the fish's weight and its success in classifying it based on its size. The test results show that this device has an average accuracy rate of 99.5%. However, minor differences in weight measurements suggest the need for further improvements. Overall, the fishing industry has enormous potential to implement this tool to increase productivity and reduce reliance on manual methods.

Growth and Depuration of Off‐Flavors in Rainbow Trout Oncorhynchus Mykiss in a Partial Recirculating Aquaculture System (PRAS)

ABSTRACTIn recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production.

Multi-biomarker assessment of chronic toxicity induced by the chemical warfare agent adamsite in Danio rerio

Several hundred thousand tons of chemical warfare agents (CWAs) were disposed of at sea, leading to environmental contamination. Among the most toxic and persistent CWAs is adamsite; however, the ecotoxicological data on this compound is limited. Presented research focuses on the long-term effects of adamsite on fish. A 28-day exposure study was conducted, evaluating the impact of adamsite on life history parameters (body length, body mass, growth rate), tissue accumulation, and the expression/activity of detoxification-related enzymes in the model fish species, Danio rerio. Results indicate that chronic adamsite exposure significantly reduces body length, weight, and growth rate of fish at trace concentrations (0.20 and 0.25 μg × L−1). Adamsite-related compounds accumulate in fish muscle tissues, increasing by approximately 4 μg per gram (dry weight) for every microgram of adamsite per litre of water during chronic exposure. The mRNA expression and activity of detoxification-related enzymes were elevated in the gills of fish, indicating oxidative stress. This study highlights the severe chronic toxicity of adamsite, which could not be anticipated based on acute toxicity. It underscores the need for comprehensive long-term toxicity assays for CWAs and emphasizes the potential ecological and health risks posed by adamsite, necessitating more stringent risk assessments.

Studying the application of a microbiological complex in sterbel growing

Abstract The main goal of the research is to establish the effect of the Bonaka-APK microbiological complex, which is a metabiotic for the management of fish autoflora and the comprehensive prevention of bacterial infections for fingerling sturgeon (sterbel). To achieve the goal, the following tasks were set: to establish the effect of Bonac-APK on fingerling sturgeon; establish the economic efficiency of its use for aquaculture. The study of the effect of the additive for growing aquaculture for yearling sturgeon fish (sterbel) was carried out with a fish weight of 130 g. The study showed that in an experiment on Sterbel the weight of fish at the end of rearing increased in experimental groups by 3.5-15.6%. The body length of fish in experimental groups increased by 1.1-2.2%. The survival rate of fish in all groups was 100%. Biochemical blood parameters of fish were within normal limits in both the control and experimental groups, which indicates that the probiotic feed additive Bonaka-APK does not have a harmful effect on the fish body. The level of lipid peroxidation increased, which indicates an increase in the antioxidant defense of the Sterbel body. The decrease in feed costs per 1 kg of weight gain compared to the control was 8.0-12.0% in experimental groups. It is recommended to use the microbiological complex Bonaka-APK in an amount of 0.4% by weight of the feed, which is a metabiotic for managing fish autoflora and complex prevention of bacterial infections for sturgeon fingerlings of the BONAKA Company.

Investigation of Microplastic Contamination in the Gastrointestinal Tract of Fish: A Comparative Study of Various Freshwater Species

The aqueous environment has been reported to be seriously threatened by the pollution of microplastics (MPs), which has been confirmed in numerous studies affecting various aquatic habitats. Despite this, few investigations exist on MP contamination in fish of specific regions. Thus, the current study aims to determine MP concentrations in the fish species of the Chhota Nagpur zone of eastern India. From August to September 2023, fish samples were collected from 10 km distance between two locations of Subarnarekha and Kharkai river banks through fishermen. Microplastics were found in the gastrointestinal tract of 45 fish of 8 species out of 48 samples. Of these species, six species were secondary consumers, while the remaining two were primary consumers. The average amount of microplastics consumed by each fish (n = 48) was 3.0 ± 1.8. A total of 144 microplastics were found in collected samples of fish species. Among the analyzed sample of MPs, 69.4% were fibers, films were (22.3%), and (8.3%) were fragments. The least contaminated species was T. ilisha (0.8 ± 0.7 particles/ind.), while L. rohita had the highest microplastic contamination (4.5 ± 1.7 particles/ind.). The present study found a negative correlation of - 0.83 between MP consumption and the mean body weight of fish. Similarly, a negative correlation of - 0.5 was found between the length of fish and MP intake. Polyamide (nylon), polypropylene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, and polyethylene polymers were found. The size of MPs ranged from 45-355 μm and mainly were fibers. They were also predominantly blue and black. Polyamide and polyvinyl chloride were the common MP types in every specimen. The possible sources of MPs were fishing nets, ropes, and packaging material. This investigation points to MP contamination in aquatic ecosystems and particular species. It provides advanced knowledge of MP pollution, sources, and effects on regional ecosystems and public health.

A Preliminary Study of the Age and Growth Patterns of a Sea Toad, Chaunax abei Le Danois, 1978, in Suruga Bay, Japan

Chaunax abei Le Danois, 1978, is a bottom-dwelling species caught by bottom trawls in Suruga Bay. In the present study, we assessed the age and growth pattern of C. abei from Suruga Bay during the period of 2021–2022 for the first time. The total length (TL) of the population ranged from 37.4–268.8 mm (mean ± SD: 124.7 ± 3.64 mm), and the fish weight (W) between 1.11–491.75 g (mean ± SD: 58.40 ± 7.25 g). The length-weight relationship was estimated as 𝑊𝑊=(2.07 × 10−5)𝑇𝑇𝑇𝑇2.996 (r2 = 0.937). Age determination was based on annual growth ring counts of transverse sections of the sagittal otoliths and age ranged from 1 to 12 years, with the majority of fish aged 4 (32.79 %) years old. The von Bertalanffy growth function was used to model the growth, and the parameters were found as: TL∞ = 468.1 mm, K = 0.056 year-1, t0 = -0.402 year. This research provides the first results on the growth of C. abei and enriches the regional fisheries biology database. Furthermore, it presents the primary population data on the growth patterns of one of the chaunacid species.

Characterisation of Snakehead Fish, Channa striata (Bloch, 1793), Byproduct and Its Gelatin Properties

This study aims to identify the characteristics of skin, bones, and scales as a biomaterial byproduct of snakehead fish, Channa striata (Bloch, 1793) before and after the extraction process into gelatin, based on 36 fresh snakehead fish samples. The biomaterials were identified, including their proximate composition (by weight of protein, fat, moisture, ash) collagen, amino acids. The physicochemical properties of gelatin in terms of yield, gel strength, viscosity pH, and functional groups were determined for scales, skin and bones. Combined, these biomaterials made up about 47.74 % of the total byproduct by weight of snakehead fish that would usually be discarded. Moisture and protein content of the skin was higher than that of scales and bone (P &lt; 0.05), and fat content was higher in bone than in skin and scales (P &lt; 0.05). The lowest ash content was in skin (&lt;1 %), compared to scales and bone (P &lt; 0.05). The collagen content of scales was higher than that of skin and bone (P &lt; 0.05). Glycine and proline in the three biomaterials were nearly equal and highest in skin, scale, and bone, respectively. There were significant differences in viscosity and gel strength of the three types of gelatin (P &lt; 0.05), the highest viscosity was in skin gelatin while the best gel strength was in scale gelatin, while pH was not significantly different (P &gt; 0.05). The application of the same method and solvent can produce different properties and characteristics of gelatin, and the presence of functional groups helps determine the occurrence of changes in the secondary structure of gelatin from the three biomaterials.

The Bioaccumulations of Metal(loid)s in the Tissues of Invasive Carassius gibelio (Bloch, 1782) Fish from the Kızılırmak River (Türkiye) and Health Risk Assessment.

The present research was an examination of the concentration levels of 10 metal(loid)s that had accumulated in the muscle, gills, and liver tissues of Carassius gibelio (Prussian carp) fish. The fish species, used as samples in the study, were obtained from the part of the river in Gülşehir (Türkiye). Besides, possible health risks to consumers were specified based on the daily estimated intake (EDI) of metal(loid)s in adults. Additionally, considering the inhabitants' frequency of fish consumption in the area, target hazard quotient (THQ), hazard index (HI), carcinogenic risk (CR), and maximum safe consumption quantity (MSCQ) values were assessed. All of the examined metal(loid)s in the research were determined in all of the tissues of the fish. Also, Fe and Zn had the highest levels in the tissues, and Pb had the lowest level. There were statistically significant differences of Fe, Co, Cu, Zn, As, Cd, and Pb among the tissues (p < 0.05). It was determined that the gender of the fish did not affect the accumulation of the metal(loid)s in the tissues. According to the research results, no significant statistical difference was found between the accumulation of the metal(loid)s (except Ni) and the size of the fish (length and weight) (p > 0.05). The estimated daily intake levels of the metal(loid)s accumulating in the eatable muscle of the samples were calculated to be lower than the reference dose limit. Besides, the THQ and the HI values lower than 1 were found. Carcinogenic risk values related to inorganic As were below 10-6. This result specifies that consumption of the fish poses no carcinogenic risks to consumers' health. It was concluded that less than 70g of C. gibelio daily consumption would not harm consumers' health.

Discarded blue mussel (Mytilus edulis): a feed ingredient that maintains growth performance of juvenile gilthead seabream (Sparus aurata) while fishmeal and fish oil are removed

ABSTRACT The total substitution of fishmeal (FM) and fish oil (FO) with sustainable feed ingredients, while maintaining acceptable growth performances and fish composition, is a challenge. Mussels have a high protein content, with essential amino acid and fatty acid (FA) profiles similar to those of FM. This study aimed to assess the potential to rear gilthead seabream (Sparus aurata) on a plant-based feed (without FM and FO) to which mussels were added. Subsequent effects on growth performance, protein content, and FA concentrations were studied. Juvenile gilthead seabream were reared for 46 days in water temperature of 21°C, in a recirculated aquaculture system composed of three fish tanks, each corresponding to one treatment: in the FMFO treatment, 342 fish were fed a commercial feed that contained FM and FO; in the plant-based feed (PBF) treatment, 345 fish were fed an experimental feed that contained only plant-based ingredients; in the mussel feed (MF) treatment, 342 fish were fed the feed from PBF supplemented with fresh mussel flesh from which the shells had been removed. Fish weighed a mean of 6.7 ± 1.3 g at stocking in each treatment. At harvest, the mean weight of fish from FMFO and MF were significantly different (23.1 ± 4.3 and 23.1 ± 5.2 g, respectively) than that from PBF (15.5 ± 3.6 g) (p < .05). Compared to the feed from FMFO, the feed from PBF decreased the percentages of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and saturated FA (14:0, 16:0) in fish, but increased those of 18:1, 18:2 n-6 and 18:3 n-3 FA. Compared to the feed from PBF, the feed from MF increased the EPA+DHA concentration in fish by 21%. Thus, adding fresh mussels to a plant-based feed yielded similar growth performances and survival rate as a commercial feed. It also improved the FA composition of fish compared to that of fish fed a plant-based feed.

Plastics at an Offshore Fish Farm on the South Coast of Madeira Island (Portugal): A Preliminary Evaluation of Their Origin, Type, and Impact on Farmed Fish

Plastic pollution is a global problem affecting all ecosystems, and it represents most of the marine litter. Offshore aquaculture is a sector particularly vulnerable to this issue. To investigate this concern, the present study employed videography to monitor macroplastics at an offshore fish farm on Madeira Island (Portugal) and analysis of fish gut content to evaluate macroplastic ingestion by farmed sea bream Sparus aurata. Our analysis revealed that the majority of identified plastic debris originated from domestic use (66.66%) and fisheries/aquaculture activities (24.99%). While the number of dead fish suitable for sampling was limited (1.05% of the total mortality), macroplastic debris ingestion was identified in 5.15% of the total mortalities and reported for the first time in species in offshore farming conditions. Fish ingested fragmented plastic sheets, with the amount positively correlated with fish weight (r = 0.621, p = 0.031, n = 12). Notably, the stretched length of these fragments exceeded 50% of the standard length of most fish. Inconsistencies were observed in the number of samples collected per cage and per week. To ensure robust results, these discrepancies should be rectified in future studies. Additionally, extending the sampling period to encompass all seasons would be beneficial for a more comprehensive understanding of seasonal variations in plastic occurrence.