Commercial Fish Species Research Articles

Transcriptome analysis identifies potential molecular mechanisms for growth of fast muscle in Chinese perch juvenile

Chinese perch (Siniperca chuatsi) is an important commercial fish species in China. Understanding the molecular mechanisms of growth and development of skeletal muscle is helpful for selection breeding and improving the growth rate of Chinese perch. We analyzed histological and transcriptomic differences in fast muscle of Chinese perch between 30 days post hatching (dph) and 60 dph using histological sections and high-throughput RNA-Seq. The results showed that the diameter of muscle fibers in 30 dph Chinese perch was mainly distributed in range of 30 − 40 μm, and that of 60 dph was primarily in the range of 40 − 50 μm. 34 differentially expressed genes (DEGs) were identified in the fast muscle of Chinese perch between 30 and 60 dph, of which 9 were up-regulated and 25 were down-regulated (60 dph vs 30 dph). The DEGs, including MYH4, ENO3, Bag3, krt13 and krt18, are associated with muscle cell differentiation and fusion in Chinese perch. The analysis of the protein–protein interaction network of DEGs revealed that FOS, junb and EGR1 may involve in the development of fast muscle. KEGG enrichment results showed that the up-regulated genes in the 60 dph were associated with several pathways related to metabolism and protein synthesis, such as glycosphingolipid biosynthesis and aminoacyl-tRNA biosynthesis. The results suggest that the development of fast muscle in Chinese perch from 30 to 60 dph is accompanied by an increase in muscle fiber diameter and changes in gene expression related to muscle cell differentiation and protein synthesis.Abbreviations: DEGs, differentially expressed genes; dph, days post hatching; FC, fold change; FDR, False Discovery Rate; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; MyHCs, Myosin heavy chains; qRT-PCR, quantitative real-time PCR.

Exploring Fish Parvalbumins through Allergen Names and Gene Identities

Parvalbumins are the main source of food allergies in fish meat, with each fish possessing multiple different parvalbumins. The naming convention of these allergens in terms of allergen codes (numbers) is species-specific. Allergen codes for parvalbumin isoallergens and allergen variants are based on sequence identities relative to the first parvalbumin allergen discovered in that particular species. This means that parvalbumins with similar allergen codes, such as catfish Pan h 1.0201 and redfish Seb m 1.0201, are not necessarily the most similar proteins, or encoded by the same gene. Here, we aim to elucidate the molecular basis of parvalbumins. We explain the complicated genetics of fish parvalbumins in an accessible manner for fish allergen researchers. Teleost or modern bony fish, which include most commercial fish species, have varying numbers of up to 22 parvalbumin genes. All have derived from ten parvalbumin genes in their common ancestor. We have named these ten genes “parvalbumin 1-to-10” (PVALB1-to-PVALB10), building on earlier nomenclature established for zebrafish. For duplicated genes, we use variant names such as, for example, “PVALB2A and PVALB2B”. As illustrative examples of our gene identification system, we systematically analyze all parvalbumin genes in two common allergy-inducing species in Japan: red seabream (Pagrus major) and chum salmon (Oncorhynchus keta). We also provide gene identifications for known parvalbumin allergens in various fish species.

Description of three new species of Kudoa Meglitsch, 1947 (Myxozoa: Multivalvulida) in commercial marine fishes from southern China, and new host records.

Multivalvulidan myxosporeans (Multivalvulida) of the genera Unicapsula Davis, 1924 and Kudoa Meglitsch, 1947 are mostly causative agents of latent and imperceptible infection in marine fishes. However, they are sometimes incriminated in causing post-mortem myoliquefaction or unsightly cyst formation in commercial fish. Despite the great commercial impacts of multivalvulidan infection, the biodiversity, host range and epidemiology of multivalvulidan species remain to be explored further, including infection of alternative annelid hosts. Therefore, this study aimed to identify multivalvulidan species and their host and/or distribution records in commercial fishes in China. Multivalvulidan infection was detected in ten commercial fish species of seven families from the South and East China Seas (Northwest Pacific Ocean) and the Eastern Central Atlantic Ocean (an imported Dagetichthys lusitanicus [de Brito Capello]). Based on morphological and molecular-genetic analyses of their small and large subunit of ribosomal RNA genes, five new host and/or geographical distribution records for five fish species are presented, and three new species in five fish species are described, namely Kudoa neoscomberomori sp. n. in Scomberomorus commerson (Lacépède); Kudoa pilosa sp. n. in Helicolenus hilgendorfi (Döderlein) (type host) and Sebastiscus tertius (Barsukov et Chen); and Kudoa tumidisporica sp. n. in Photopectoralis bindus (Valenciennes) (type host) and Nuchequula nuchalis (Temminck et Schlegel). This study provides new data on multivalvulidan diversity in the ocean ecosystem.

Pervasive Microplastic Ingestion by Commercial Fish Species from a Natural Lagoon Environment

Microplastics have emerged as a significant global environmental concern in the recent decade. The aim of this study was to elucidate microplastic contamination of commercial fish species in a natural lagoon environment. Microplastic contamination was examined in the gastrointestinal tracts and gills of 157 commercial fish from 18 species with varying feeding habits in a vital and sensitive lagoon ecosystem, which connects to the Indian ocean. Microplastics were extracted using digestion, followed by stereomicroscopic inspection using Nile Red stain, and identified via μ-FTIR analysis. Over half of studied fishes ingested microplastics (54.14%). Filaments (50%) and blue items (43%) were the most commonly ingested. Of all the fish species, Eubleekeria splendens had the highest average concentration of microplastics in GIT (1.41 ± 2.52 items/g w.w. tissues), although no statistically significant difference in amount of ingested microplastics (items/g w.w. tissues) was observed among species. The highest concentrations of inhaled microplastics were recorded in Sillago vincenti (1.38 ± 1.30 items/g w.w. tissues). The majority of the extracted microplastics (33%) belonged in the size class 500–1500 μm with rayon, polyethylene terephthalate, and polypropylene as the primary polymers. This study found no correlation between microplastic ingestion and fish species and feeding habits, but a positive correlation with fish size was observed. These findings reveal widespread microplastic contamination in edible fish, posing potential risks to commercially important species due to increasing pollution in lagoon ecosystems.

The mechanisms of effects of oil-derived polyaromatic hydrocarbons on cardiac electrical activity in navaga cod (Eleginus nawaga)

The intensive development of oil and gas industries in the Arctic threatens Arctic aquatic ecosystems. The toxic and primarily lethal cardiotoxic effects of oil in living organisms are believed to be associated with polyaromatic hydrocarbons (PAHs), and previous works revealed the electrophysiological mechanisms of action of individual oil-derived PAHs. However, the physiological effects of a complex PAHs mixture in oil water-soluble fraction (WSF) have not been previously studied. This study is focused on the effects of oil WSF on electrical activity and major ionic currents in the working myocardium of navaga (Eleginus nawaga), which is one of the most important commercial fish species in the Arctic. We found that 1% and 10% solutions of oil WSF cause a marked increase in the duration of action potentials (APs) in navaga cardiomyocytes. This effect appears to be due to the suppression of rapid delayed rectifying current IKr (IC50 about 3% in ventricular and atrial myocardium). At higher concentrations, oil WSF also suppressed calcium current ICaL (IC50 = 10.6%), which led to a decrease in the contractile activity in isolated myocardial preparations. Unlike individual tricyclic PAHs, oil WSF did not affect fast sodium current INa and AP upstroke velocity. An assessment of the content of tricyclic PAHs in 10% solution of oil WSF showed that their total concentration is relatively low and does not exceed 100 nM. Thus, oil WSF also has a powerful cardiotoxic effect in fish myocardium, but its effects differ from the previously studied effects of tricyclic PAHs and suggest the presence of yet unexplored oil compounds that have a more powerful toxic potential against ERG channels.

High temperature and hyperkalemia increase vulnerability of navaga cod (Eleginus nawaga) cardiomyocytes to the ecotoxicant 3-methyl-phenanthrene

Oil and gas mining and transportation in the Arctic can lead to release of polycyclic aromatic hydrocarbons (PAHs) in the ocean and freshwater basins. PAHs are known for their toxic effects in fish hearts, including the inhibition of main ionic currents (IKr, INa and ICaL) in fish cardiac myocytes. The present study is the first one to assess the effect of a particular PAH abundant in crude oil and diesel, namely 3-methyl-phenanthrene (3-MP), on the electrical excitability (EE) of cardiomyocytes from navaga cod (Eleginus nawaga), commercial fish species from the Arctic. Action potentials (APs) were elicited in current-clamp experiments at 9, 15 and 21 °C, and AP characteristics and the current needed to elicit APs were examined. Also, the effects of 3 μM 3-MP were tested at 3 temperatures and in normal (3.5 mM) and high (8 mM) extracellular K+ concentrations.Elevation of temperature leads to hyperpolarization of resting membrane potential and AP shortening, but does not decrease EE. 3-MP was found to suppress EE in cardiomyocytes at 9 and 15 °C, but not at 21 °C. High extracellular K+ itself drastically decreases EE, although it does not worsen the effect of 3-MP. However, combination of hyperthermia and high K+ leads to augmentation of depressive effect of 3-MP on EE. We hypothesize that hyperthermia rescues Na+ channels from inactivation due to membrane hyperpolarization, thereby compensating for the partial inhibition of INa by 3-MP. However, elevation of extracellular K+ nullifies this protective mechanism by depolarizing the resting potential and aggravates the effect of 3-MP.

Mercury content and consumption risk of the invasive Arapaima gigas (paiche) in Bolivia

Mercury is a global pollutant present in the environment. The most frequent non-occupational human exposure pathway is fish consumption. Generally, fish species of large size and with carnivorous or omnivorous feeding habits have higher mercury concentrations. The invasive fish Arapaima (popularly known as paiche), an omnivorous large-sized species introduced in northern Bolivian Amazon about 50 years ago after escape from aquaculture in Peru, has successfully colonized this region and is now the main commercial fish species. Consumption of this species in Bolivia is increasing, and an evaluation of the risk of mercury exposure for human health is warranted. Muscle samples from 86 fish were taken from four different sub-basins (Orthon, Madre de Dios, Beni and Yata). 8.1% of the samples showed mercury content above the safe consumption recommendation of the World Health Organization (0.5 mg kg-1). Samples from the Madidi and Yata rivers scored the highest mean concentrations (0.367 and 0.306 mg kg-1, respectively), whereas individuals from the lower Beni subbasin showed the lowest (0.105 mg kg-1). According to our results, the maximum recommended paiche meat consumption is 316 g per week, divided into two meals, which is in agreement with international recommendations for fish consumption (227 g to 340 g per week), although this can vary according the place of origin of the meat. Following these recommendations, mercury exposure through paiche consumption should not represent a risk for human health.

Fisheries and biological characteristics and state of stocks of the main commercial fish species in Beloye Lake

The current composition of the ichthyofauna and the importance for fisheries of the main fish species in Beloye Lake (Vologda Region) is described in the article based on research materials from 2018 – 2022. The biological features and commercial use of twelve most valuable fish species are summarized as result of the composition of industrial and research catches studies. The size and age composition of catches, the age of puberty, the timing and conditions of spawning, and the feeding patterns of fishes were studied. The influence of net fishing gear with different mesh spacing on commercial fish populations and the magnitude of nets fishing productivity (fishing effort) were studied for the first time. The role of the most important fish species for industrial fisheries in Beloye Lake was assessed.

Status of the fish stocks and fisheries of the main commercial fish species of Lake Ladoga in the XXI century

In the 21st century, there has been decrease in stocks and catches of aquatic biological resources in Lake Ladoga as well as a change in the structure of the fish population in the Lake, primarily due to changes in the trophic capacity of the reservoir. Smelt dominates in the commercial catches. Stocks and catches of autumn-spawning whitefish and lakecisco show obvious downward trend. Biological and commercial indicators of the pike-perch population are at a low level. Stocks of bream, roach and perch are in good condition.

Whether the summer fishing moratorium can improve the status of fisheries resources in the yellow sea and Bohai Sea

The China government has introduced many strategies in fisheries management of the Yellow Sea and the Bohai Sea, the most stringent of which is the summer fishing moratorium. Whether the summer fishing moratorium can restore fishery resources has always been a concern. In this study, we selected eight representative commercial fish species the Yellow Sea and Bohai Sea, including Pampus argenteus, Trichiurus lepturus, Scomberomorus niphonius, Ilisha elongata, Thamnaconus modestus, Scomber japonicus, Engraulis japonicus and Larimichthys polyactis, and used the JABBA method to study their historical exploited dynamics and current stock status. We evaluated the effectiveness of the summer fishing moratorium based on the increments of biomass and catch after its implementation and adjustments. P. argenteus and S. niphonius stocks were in the healthy status in 2022, the other six fisheries stocks were overexploited. The summer fishing moratorium had a strong conservation effect, especially after the first implementation in 1995, with the biomass of six fish species increased and the catch of seven species increased, and the total average biomass and catch increments were 21.22 % and 89.72 %. This positive effect was also reflected after the first adjustment in 2003. Although the moratorium duration was continuously extended after the second and third adjustment, the conservation effect was offset by the flooding of fishing efforts immediately after the moratorium. For the six overexploited stocks, we suggest that the allowable catch of E. japonicus, T. lepturus, L. polyactis, S. japonicus, I. elongata and T. modestus is at most 527.91 kt, 147.51 kt, 93.43 kt, 81.51 kt, 1.25 kt and 4.95 kt in the Yellow Sea and Bohai Sea, respectively.

Diving into the fish pathology of an important commercial fish species: the case of the European hake (Merluccius merluccius Linnaeus, 1758) in the northwest Mediterranean Sea

Diving into the fish pathology of an important commercial fish species: the case of the European hake (<i>Merluccius merluccius</i> Linnaeus, 1758) in the northwest Mediterranean Sea

Liquid-liquid phase separation is essential for reovirus viroplasm formation and immune evasion.

Grass carp reovirus (GCRV) poses a significant threat to the aquaculture industry, particularly in China, where grass carp is a vital commercial fish species. However, detailed information regarding how GCRV viroplasms form and their specific roles in GCRV infection remains largely unknown. We discovered that GCRV viroplasms exhibit liquid-like properties and are formed through a physico-chemical biological phenomenon known as liquid-liquid phase separation (LLPS), primarily driven by the nonstructural protein NS80. Furthermore, we confirmed that the liquid-like properties of viroplasms are essential for virus replication, assembly, and immune evasion. Our study not only contributes to a deeper understanding of GCRV infection but also sheds light on broader aspects of viroplasm biology. Given that viroplasms are a universal feature of reovirus infection, inhibiting LLPS and then blocking viroplasms formation may serve as a potential pan-reovirus inhibition strategy.

Assessment of microplastic pollution in eleven commercial fish species in the Gulf of İzmir (Aegean Sea, eastern Mediterranean)

With global plastic production reaching 400 million tons in 2022, concerns about plastic pollution in the seas are increasing day by day. Therefore we focused on the abundance, characteristics, and chemical composition of potential anthropogenic origin MPs within the gastrointestinal tracts (GITs) of 11 commercial fish species in the Gulf of İzmir, an area heavily impacted by human activities. Within the scope of the study, 152 fish were sampled, and microplastics were found in 64 fish. In total, 77 MPs were identified based on ATR-FTIR analysis. Significant differences were found between species regarding MP abundance. Among the species, Scomber scombrus showed the highest MP ingestion. The MP abundance in the GIT of fish decreases from surface to deeper waters. There were also significant differences (p < 0.05) in MP abundance between pelagic and demersal fish species. Results showed that 50.6 % of MPs were fragments, and 49.4 % were fibers. The most common color was black. Seven polymer types were identified, and PE was the most common. The size of the identified MPs ranged from 101 to 4901 μm, and the average value was 715.83 ± 860.66 μm. This study sheds light on the MP contamination within commercial fish species in the Gulf of İzmir and emphasizes the urgent need for enhanced marine ecosystem conservation strategies. Our findings can serve as a basis for future studies by providing essential baseline data for implementing necessary policies and regulations.

Sustainable valorisation of freshwater fish by‐products to gelatin and fish oil by hydrothermal extraction

SummaryThis study explores the potential of hydrothermal extraction as an innovative valorisation method for the simultaneous production of gelatin and fish oil from fish byproducts. It offers an environmentally friendly alternative to conventional solvent‐based techniques by minimising the use of chemical solvents and water. We researched various major commercial freshwater fish species: striped catfish, catfish, and tilapia, and achieved a gelatin product that reflects commercial standards in chemical structure, gel strength, and pH level. The striped catfish gelatin showed the highest gel strength and viscosity (66.01 ± 0.83 g bloom and 15.3 ± 0.1 cP), but was produced at a lower yield than the catfish gelatin. On the other hand, striped catfish produced the highest yield of fish oil (13.56 ± 0.21%) and has the highest omega 3 content (3.72 ± 0.02%) than other fish oil. This innovative study demonstrates the potential of hydrothermal extraction as a sustainable method for producing gelatin and fish oil, offering eco‐friendly and nutritional benefits across a range of applications.

Environmental drivers affecting the status of top commercial fish stocks in the Baltic Sea: review

IntroductionLike in many parts of the world, the Baltic Sea experiences a multitude of processes and stressors that influence fish stock dynamics. This paper compartmentalizes 250 publications that examine the cumulative effects and trade-offs of some of the most significant environmental drivers (temperature change, hypoxia, nutrient enrichment, acidification, low salinity, and food-web dynamics) on the ecology of top commercial fish species in the Baltic Sea (cod, sprat, whiting, herring, flounder, and plaice).MethodsA systematic review method was applied to ensure rigorous coverage of existing literature and to provide a comprehensive synthesis of the current knowledge on the subject.ResultsThe results illustrate the extent of scientific research applicable to commercial fisheries knowledge in the Baltic Sea and identify which pressures have the greatest negative impacts on which stocks. Additionally, the findings demonstrate how well top commercial fish species have adapted to the changing environmental conditions of the Baltic Sea. In doing so, the review illustrates the upcoming challenges and underscores which stocks are likely to dominate in the future and which will face difficulties.DiscussionBy considering ecosystem-based fisheries management, this paper emphasizes the need to account for complex ecosystem interactions beyond single-stock monitoring. With increased natural hazards, top commercial fish species have reacted differently, depending on the region and their adaptive capabilities. In most cases, Clupeidae species have adapted the best to their new surroundings, Pleuronectidae resilience is varied, while Gadidae species are finding the Baltic Sea increasingly challenging.

Methylmercury in commercial fish species from the Erhai Lake Basin, Southwest China: concentrations, health risk assessment, and implications for future monitoring.

Erhai Lake, a highland lake situated in Southwest China, provides critical aquatic protein sources for the local community, and its preservation is vital due to the sensitivity of alpine freshwater ecosystems to disturbance. However, there is a lack of research on the contamination status of methylmercury (MeHg) in aquatic organisms of the Erhai Lake Basin. MeHg concentrations in important commercial fish species from the Erhai Lake were examined, and the potential health risks associated with human consumption were assessed. Our results showed significant inter-species differences in fish muscle MeHg: the carnivorous S. asotus exhibited the highest level (303ng/g; ww), while that of the detritivorous R. ocellatus was the lowest (3.86ng/g). Moreover, MeHg concentrations in P. fulvidraco and C. auratus collected from the Luoshi River (a major tributary of Erhai Lake) were significantly higher compared to those from the Erhai Lake, indicating possible river-based input of MeHg into the Erhai Lake. Additionally, our study revealed a significant positive correlation between the MeHg levels and the length as well as weight of the examined fish species. All the fish species analyzed in our study had MeHg concentrations within the limits of China's food safety standard. Nevertheless, a relatively low consumption quantity of 16g per day of certain species (i.e., S. asotus) may still pose potential health risks especially for children. The present study provides baseline data for MeHg monitoring and risk assessment in the Erhai Lake Basin, and warrants continued monitoring and source investigation.

Baseline Study on Microplastic Contamination in Commercial Fish from the Vellar Estuary, South India

Microplastic (MP) contamination has emerged as a serious worldwide issue. Human activity, commercial operations, and fishing are all concentrated around the coast, resulting in high levels of fish MPs contamination. This preliminary investigation aims to examine MP accumulation in commercial fish caught in the Vellar estuary region. Fish samples were collected from the estuary, and MPs in the gills and gastrointestinal tracts of three commercial fish species were analyzed for quantity, type, shape, and color using standard laboratory techniques. MPs particles were found in 2.55-4.35 items per individual fish, with an overall average of 3.2 particles in the gills and 5.5 in the gastrointestinal tract. The majority of the MPs were blue and green fibers with a diameter of 0.5-1 mm. Fragmented pieces of MPs and fibers were abundant in the gut. These findings demonstrated the extent of MPs contamination in Vellar estuary fish tissues, serving as a baseline for MPs loading in the estuary. This study has significant implications for food safety, highlighting the dangers of MPs in fisheries and aquaculture. It also identifies knowledge gaps in the long-term effects of MPs, suggesting a need for further research in this sector.

Some biological aspects of chacunda gizzard shad, Anodontostoma chacunda (Hamilton, 1822) from the Bay of Bengal, Bangladesh

Anodontostoma chacunda is a commercial fish species in the market and is usually consumed in fresh, smoked, and dried forms. This study investigated the population structure, length-weight relationships (LWR), condition factor (KF), size at sexual maturity (Lm), and breeding season of A. chacunda in the Bay of Bengal, Bangladesh, using the data collected from January to December 2020. A total of 1061 individuals were collected in the sampling period with the help of fishers. Total length (TL) and body weight (BW) were measured using a measuring board and an electronic balance. The TL ranged from 12.50 to 26.70 cm. The allometric coefficient (b) value was 3.34, indicating positive allometric growth in this species. The fish is in good condition, evidenced by its condition factor (KF) ranging between 0.88 and 1.73. Maturity size ranged from 15.40 to 16.80 cm (TL) based on three distinguished models. Spawning time lasts from January to May and from September to December. The peak spawning time was December of A. chacunda in the Bay of Bengal. This information could prove valuable for fisheries researchers and biologists, facilitating efforts toward the conservation and sustainable management of this species.

Содержание железа в органах и тканях каспийского рыбца Vimba vimba persa (Pallas)

The object of research in this work is the Caspian vimba Vimba vimba persa (Pallas), one of the commercial fish species of the Caspian Sea. Fish samples taken in the middle part of the Caspian Sea in the autumn period from 2020 to 2023 were analyzed. The work includes studies of Fe concentration in organs and tissues (muscle tissue, gonads, liver, gills, gastrointestinal tract) and food coma of the Caspian vimba Vimba vimba persa (Pallas) aged 2 and 3 years old. It was revealed that Fe accumulation in the liver occurs to a greater extent in the body of the Caspian vimba, and to a lesser extent in muscle tissue. A comparative analysis of the metal concentration was carried out depending on the sex and age of the fish. It was found that females accumulate Fe to a lesser extent than males. The average concentration of Fe in the body of 2-year-old females was 184.11 mg/kg of dry matter, and in 3-year-old females 163.58 mg/kg of dry matter. The average concentration of Fe in the body of males aged 2 years was 203.39 mg/kg of dry matter, and in males aged 3 years 225.92 mg/kg of dry matter. There is also an increase in the concentra-tion of Fe in the body of males upon reaching the age of 3, and a slight decrease in concentration in females. There are sexual differences in the distribution of metal in fish organs (liver, gills, gonads). Of particular interest is the dynamics of metal in the gonads (increases in females, decreases in males). There occurs redistribution of metal in the organs and tissues of fish.

Are microplastics a new cardiac threat? A pilot study with wild fish from the North East Atlantic Ocean

Global environmental contamination by microplastics (MPs) is a growing problem with potential One Health impacts. The presence of MPs in vital organs, such as the heart, is of particular concern, but the knowledge is still limited. The goal of the present pilot study was to investigate the potential presence of MPs in the heart of wild specimens of three commercial fish species (Merluccius merluccius, Sardina pilchardus, and Trisopterus luscus) from the North East Atlantic Ocean. Heart samples from 154 fish were analysed for MP content (one heart sample per fish). A total of 44 MPs were recovered from heart samples from the three species. MPs had varied chemical composition (5 polymers), shapes (4) and colours (5). Differences in the profile of the MPs among species was observed (p ≤ 0.05). Thirty fish (19%) had MPs in their hearts, with a total mean (±SD) concentration of 0.286 ± 0.644 MPs/fish. S. pilchardus had the highest heart contamination (p ≤ 0.05). There were no significant (p > 0.05) differences between M. merluccius and T. luscus. These findings in fish with different biological and ecological traits together with literature data suggest that heart contamination likely is a disseminated phenomenon. Therefore, further research on the presence of MPs in the cardiovascular system and its potential health effects is very much needed.