Bio-economic indicators of fisheries: impact of variations in landings and fish size on market prices in Istanbul Fish Market.

Fisheries are of immense importance to Mediterranean countries, for protein, employment and livelihoods. Studies addressing the factors affecting fish price dynamics are of interest to examine their drivers as prices often dictate target fisheries. This study investigates fish market prices in relation to landings and fish sizes from Türkiye's largest fish market in Istanbul as the study site. A total of 39 wild marine taxa were examined for their landed catch (kg) and average prices (per unit/TRY) from 2006 to 2019. We found fish prices increased from small pelagic to medium pelagic to demersal fish. GAM model results for inter-species tests showed a strong positive effect of local maximum length (p < 0.01) and a weaker positive effect of trophic level and vulnerability (p < 0.1) on fish market price, but that landings amounts have no significant effect as a single predictor. Monthly price variations of bluefish and bonito were completely different than other species dynamics, as the last substantial commercial medium pelagic fish species left; highest monthly prices were related to the highest monthly landings for bonito and for the non-closure period for bluefish. Market prices as economic indicators for fisheries may have the potential to reveal ecosystem variations as well as socioeconomic drivers. Databases including extensive data for key fish sales centers can be used to help understand fishery dynamics from an ecosystem perspective, especially for data-poor regions like Türkiye.

Diversity and characteristics of commercial Red Sea fish species based on fish market survey: informing management to reduce the risk of overfishing.

In small-scale fisheries (SSFs), where the sampling of many small boats and landing sites sometimes is not practical, fish market surveys represent an alternative way to obtain key fisheries data. This study analyses the diversity and characteristics of commercial Red Sea fish species landed in the Egyptian coast, including family, species-specific abundance, biomass, size and price by surveying the largest local fish market on the Egyptian Red Sea coast, over the course of a year (July 2021-June 2022) to also reflect any seasonality of these variables. Based on 53 survey visits, a total of 131,795 fish individuals, belonging to 111 species, and 22 families, were identified, recorded and measured. The analysis focused on the 60 most abundant species (104,420 individuals, 15 families). The surveys revealed that the most abundant families were Serranidae, Lethrinidae and Scaridae. Carangidae also was one of the most important families in terms of biomass. The most abundant species were Lethrinus mahsena, Sargocentron spiniferum and Lethrinus nebulosus. About 60% of revenue comes from the four families Serranidae, Lethrinidae, Scaridae and Lutjanidae. In terms of prices, the most expensive categories were species belonging to Serranidae, Lethrinidae and Lutjanidae families, such as Plectropomus pessuliferus marisrubri, Argyrops spinifer, L. nebulosus and Variola louti. The overall mean prices were higher in spring and summer months likely due to tourism flows. The mean size of many species, including the most valuable and abundant ones, is below the length of maturity. These results provide important benchmarks for monitoring future changes and shed important insights for fisheries management. Co-organised Dutch auctions would provide reliable data when combined with a strict monitoring effort to avoid any sale of the catch outside these official auctions. Other monitoring tools and methods are also recommended in the discussion.

Unusual Localization of Hysterothylacium incurvum in Xiphias gladius (Linnaeus 1758) Caught in the Atlantic Ocean.

This study represents the first report of Hysterothylacium incurvum within swordfish (Xiphias gladius) heart chambers. Swordfish is a large pelagic teleost, considered one of the most appreciated fish worldwide. Among swordfish parasites, Anisakis sp. and Hysterothylacium sp. have been used to evaluate biological and ecological aspects of this teleost. Between 2021 and 2022, 364 X. gladius hearts, caught from the Atlantic Ocean (FAO 27.IXa and FAO 34 areas), were collected at the Milan fish market (Lombardy, Italy). Three specimens from FAO 27.IXa was positive for seven adult nematodes (p = 1.55%) within the heart chambers. Of these, three specimens were found within the bulbus arteriosus and 4 in the ventricle. All parasites were stored in 70% ethanol and processed for parasitological and molecular analysis using Cox2, ITS regions/ITS-I-5.8S-ITS-II, and rrnS genes. The analysis allowed us to identify the retrieved parasite as H. incurvum. According to our evaluation, the final localization is due to the movement of L3 larvae from the coelomic cavity to the bloodstream, with consequent development to the adult stage within the heart. Finally, the parasite localization, considered non-marketable fish parts, does not pose a significant risk to consumers, also considering the low zoonotic potential of H. incurvum.

Metals Bioaccumulation in 15 Commonly Consumed Fishes from the Lower Meghna River and Adjacent Areas of Bangladesh and Associated Human Health Hazards.

The lower Meghna River, the easternmost part of the Ganges Delta, faces severe anthropogenic perturbations as it receives a huge discharge and industrial effluents. To measure the metal concentrations and human health hazards, edible tissues of 15 commercially important fish species were collected from the local fish markets and the lower Meghna River, Bangladesh. Trace and heavy metals such as Pb, Cr, Cu, Zn, Mn, Fe, Hg, Ni, Ca, Co, Se, Rb, Sr, and As were detected using the Energy Dispersive X-ray Fluorescence (EDXRF) method. The hierarchy of mean metal concentrations obtained was: Fe (162.198 mg/kg) > Zn (113.326 mg/kg) > Ca (87.828 mg/kg) > Sr (75.139 mg/kg) > Cu (36.438 mg/kg) > Se (9.087 mg/kg) > Cr (7.336 mg/kg) > Mn (6.637 mg/kg) > Co (3.474 mg/kg) > Rb (1.912 mg/kg) > Hg (1.657 mg/kg) > Ni (1.467 mg/kg) > Pb (0.521 mg/kg) > As (BDL). Based on the metal concentration obtained, the carnivorous species contained more metals than omnivores and herbivores. Similarly, the euryhaline and benthic feeder fishes had more metals than the stenohalines and demersal fishes. The metal pollution index (MPI) suggested that the highly consumed fish species Tilapia (Oreochromis mossambicus) and Rui (Labeo rohita) accumulated higher metals than other fishes. Both the Targeted Hazard Quotient (THQ) and Hazard Index (HI) values for adult and child consumers were <1, indicating that consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, carcinogenic risk (CR) exposure of Cr for all the consumers was found in the acceptable range (10−6 to 10−4), but the CR exposure of Pb was negligible for all the consumers. The correlation, principal component analysis (PCA), and cluster analysis were conducted to identify the sources of metals identified from the fish tissue. The results indicated that the probable sources of the pollutants were anthropogenic, arising from agricultural activities, electroplating materials, and lubricants used near the study area. However, the present study showed a different metal concentration in the samples at different levels but within the threshold levels non-carcinogenic and carcinogenic health risks; hence, the fishes of the area, in general, are safe for human consumption.

Drawing the line between sustainable and unsustainable fish: product differentiation that supports sustainable development through trade measures.

BACKGROUND: Unsustainable production practices and increased demand for fish have aggravated negative social, ecological, and environmental impacts in fisheries and aquaculture. Measures to correct bad practices have mainly been introduced by private actors. However, there is increased demand for state intervention, particularly regarding trade regulations for fish and other agricultural products. Building on discussions about product differentiation through trade measures that favour sustainable products, this study looked at how sustainable and unsustainable fish has been distinguished in Switzerland. In interviewing experts in the fish trade and sales business in Switzerland, the research aimed at understanding the actors and forces that shape the concept of sustainable fish in the country. RESULTS: Three ways of product differentiation for sustainable fish by private actors were identified in Switzerland: ecolabels, "Swiss produce", and recommendations in the form of a "consumer guide for fish". Currently, price is the main constraint on consumption of sustainable products in the country. Defining "sustainable fish" is challenging and subject to interpretation. All existing measures to differentiate sustainable from unsustainable fish products in Switzerland have shortcomings, particularly in terms of discrimination and inclusiveness. Fish ecolabels play a key role in product differentiation, but experts believe that they fail to accommodate all aspects of sustainability. CONCLUSION: Our findings imply that the Swiss state should play a more important role if it aims to fulfil the promise of article 104a of the Swiss Constitution, which seeks to foster sustainable production and cross-border trade relations that contribute towards this goal. Preferred trade treatment for sustainable fish products is a potential option to increase the production and consumption of sustainable fish. When designing measures for product differentiation, a careful choice is paramount to address sustainability in a holistic, inclusive, and transparent way and in order not to violate existing trade obligations. Due to similarities between the Swiss and other fish markets, we assume that governments in general and members of the European Union in particular must play an active role in shaping the definition and trade of sustainable fish products if they seek to comply with their sustainability commitments. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12302-021-00551-6.

Treatment of fish market wastewater and energy production using halophiles in air cathode microbial fuel cell.

The present study is aimed to treat the fish market wastewater coupled with electricity production using halophiles in microbial fuel cell (MFC) technology under saline condition (4.6%). Halophilic consortium obtained from desalination plant brine water was used in the lab scale air cathode microbial fuel cell (ACMFC) reactor equipped with carbon brush and carbon cloth as anode and cathode. ACMFC (260 mL capacity) was operated with fish market saline wastewater at different organic load (OL) from 0.41 to 2.01 g COD/L with 20 day HRT (Hydraulic Retention Time). Total chemical oxygen demand (TCOD) removal at OL 0.41, 0.82 and 1.21 g COD/L was 68%, 77% and 84% in ACMFC. Correspondingly, soluble chemical oxygen demand (SCOD) removal was 63%, 74% and 81% respectively. The optimized OL for the treatment of fish market wastewater was 1.62 g COD/L, where the TCOD (90%), SCOD (88%), TSS (Total Suspended Solids) removal of 71% coupled with power generation of 902 mV (Power density 420 mW/m2, Current density 550 mA/m2) was recorded. Columbic efficiency at OL 0.41 g COD/L was 56% and declined at OL 0.82, 1.21, 1.62 and 2.01 g COD/L to 48%, 39%, 29% and 17%. Increment in OL to 2.01 g COD/L revealed decrease in TCOD (64%), SCOD (60%), TSS (45%) removal and energy production. The bacterial strains present in the halophilic consortium were Ochrobactrum, Marinobacter, Bacillus, Rhodococcus, Flavobacterium, Alicyclobacillus, Pseudomonas, Martelella, Stenotrophomonas, Xanthobacter, and Microbacterium. High dominance of Ochrobactrum, Marinobacter and Bacillus was observed at optimized OL of 1.62 g COD/L in ACMFC. Further research on pilot scale MFC lead the way to technology transfer for the treatment of wastewater with corresponding energy production in industrial sector.

Prevalence of antibiotic resistance genes in wastewater collected from ornamental fish market in northern China.

Large amounts of antibiotics/disinfectants are used in the farming of ornamental fish so as to prevent and treat bacterial infection. This may exert considerable selection pressures on the prevalence and propagation of antibiotic resistance genes (ARGs). However, the levels of ARGs and their potential prevalence mechanism in the wastewater of the ornamental fish industry remains unclear. In this work, wastewater is collected from a representative ornamental fish market (OFM) that is located at the northern China to study the occurrence and abundance of 21 ARGs and 2 integrase genes. Results indicated that 15 different ARGs and 2 integrase genes are existent and prevalent in the wastewater of OFM, whereby concentrations range from 2.01 to 10.34 copies/L. Proteobacteria, Bacteroidetes, Verrucomicrobia, and Firmicutes are the predominant phyla in the wastewater samples. 17 species of human opportunistic pathogens are present with relative abundance of up to 0.01%, which suggests a considerable risk of pathogens acquiring and disseminating ARGs. Moreover, oxytetracycline, ciprofloxacin, norfloxacin, sulfadiazine, and chloramphenicol are most frequently detected in wastewater, with concentrations of up to 1150, 877, 514, 1970, and 1700 ng/L, respectively. Notably, good correlations have been determined among ARGs and antibiotics, non-antibiotic environmental factors in wastewater of OFM. This current study reveals, for the first time, that OFM is a previously unperceived reservoir for ARG prevalence in aquatic environment and water environmental factors (particularly antibiotics), and their induced shifts in the microbial communities are the key factors for distribution of ARGs in OFM.

Kudoa yasai n. sp. (Multivalvulida: Kudoidae) from the skeletal muscle of Macrodon ancylodon (Sciaenidae) on the northern Atlantic coast, Brazil.

A new parasite species, Kudoa yasai n. sp. (Multivalvulida), is described from the king weakfish (Macrodon ancylodon), which is an important commercial fishery resource on the Brazilian Amazon coast. A total of 190 M. ancylodon specimens were obtained from the central fish market of the town of Bragança, and pseudocysts were found in the skeletal muscle fiber samples of all (100%) of the specimens, although no inflammatory reaction was observed in any of the cases. The myxospores are quadrate in shape with four polar capsules of equal size, 6.9 ± 0.94 µm long, 8.2 ± 0.39 µm wide, and 5.5 ± 0.60 µm thick. The polar capsules are 1.8 ± 0.26 µm in length and 1.4 ± 0.18 µm in width. The morphological and morphometric parameters, together with the phylogenetic analysis of a partial sequence of the 18S (SSU rDNA) gene, all indicate conclusively that Kudoa yasai n. sp. is a new species, distinct from all other Kudoa species. The study also verified the loss of quality in the meat of the host fish (M. ancylodon) sold in the Bragança market, which reinforces the need for the more systematic control of the quality of the product and the prevention of possible health problems for the consumer.

Molecular Detection and Antibiotyping of Multidrug-Resistant Salmonella Isolated from Houseflies in a Fish Market.

Houseflies (Musca domestica) are well-known mechanical vectors for spreading multidrug-resistant bacteria. Fish sold in open markets are exposed to houseflies. The present study investigated the prevalence and antibiotypes of multidrug-resistant (MDR) Salmonella spp. in houseflies captured from a fish market. Direct interviews with fish vendors and consumers were also performed to draw their perceptions about the role of flies in spreading antibiotic-resistant bacteria. A total of 60 houseflies were captured from a local fish market in Bangladesh. The presence of Salmonella spp. was confirmed using PCR method. Antibiogram was determined by the disk diffusion method, followed by the detection of tetA, tetB, and qnrA resistance genes by PCR. From the interview, it was found that most of the consumers and vendors were not aware of antibiotic resistance, but reported that flies can carry pathogens. Salmonella spp. were identified from the surface of 34 (56.7%) houseflies, of which 31 (91.2%) were found to be MDR. This study revealed 25 antibiotypes among the isolated Salmonella spp. All tested isolates were found to be resistant to tetracycline. tetA and tetB were detected in 100% and 47.1% of the isolates, respectively. Among the 10 isolates phenotypically found resistant to ciprofloxacin, six (60%) were found to be positive for qnrA gene. As far as we know, this is the first study from Bangladesh to report and describe the molecular detection of multidrug-resistant Salmonella spp. in houseflies in a fish market facility. The occurrence of a high level of MDR Salmonella in houseflies in the fish market is of great public health concerns.

Qualitative and quantitative assessment of the presence of ciguatoxin, P-CTX-1B, in Spanish Mackerel (Scomberomorus commerson) from waters in New South Wales (Australia).

Ciguatera Fish Poisoning (CFP) is a tropical disease caused by the consumption of fish contaminated with ciguatoxins (CTXs). Currently, the only feasible prevention methods for CFP are to avoid the consumption of fish of certain species from some regions, avoid larger fish of certain species, or avoid all fish caught from specific regions. Here, we quantified levels of P-CTX-1B in Spanish Mackerel (Scomberomorus commerson), which is the main fish species that causes CFP in New South Wales and Queensland, Australia, using LC-MS detection against a toxin standard. We found detectable P-CTX-1B in both flesh and liver tissues in fish from New South Wales (n = 71, 1.4% prevalence rate, with a confidence interval of 1%-4%, and 7% prevalence, 1%-12%, in flesh and liver, respectively). In the small sample of fish from Queensland, there was a 46% prevalence (19-73%, n = 13). Toxin levels found were 0.13 µg kg-1 to <0.1 µg kg-1 in flesh, and 1.39 µg kg-1 to <0.4 µg kg-1 in liver, indicating that liver tissue had a significantly higher concentration (∼5 fold) of P-CTX-1B. No apparent relationship was observed between the length or weight of S. commerson and the detection of P-CTX-1B in this study. Footnote.

Isolation and identification of bacteria from marine market fish Scomberomorus guttatus (Bloch and Schneider, 1801) from Madurai district, Tamil Nadu, India.

The present study was conducted to evaluate the hygienic quality and freshness of fish Indo-pacific King Mackerel "Scomberomorus guttatus" through the investigation of the occurrence of bacteria which is an indicator for fish quality. Fishes were collected every fortnight from Madurai fish market on monthly twice of January 2014 to March 2014. Skin surface of the fish was examined. Escherichia coli, Proteus vulgaris, Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa and Staphylococcus aureus were identified by Biochemical tests (IMViC Tests). Among the six bacterial species E. coli and K. pneumonia were found in all the collected samples where as other bacterial species were not found. The result of this study revealed that raw fish sold in Madurai fish market has high contamination so the presence of the bacterial species has strongly suggested the urgent need to improve the quality control systems in Madurai fish market.

It is the economy, stupid! Projecting the fate of fish populations using ecological-economic modeling.

Four marine fish species are among the most important on the world market: cod, salmon, tuna, and sea bass. While the supply of North American and European markets for two of these species - Atlantic salmon and European sea bass - mainly comes from fish farming, Atlantic cod and tunas are mainly caught from wild stocks. We address the question what will be the status of these wild stocks in the midterm future, in the year 2048, to be specific. Whereas the effects of climate change and ecological driving forces on fish stocks have already gained much attention, our prime interest is in studying the effects of changing economic drivers, as well as the impact of variable management effectiveness. Using a process-based ecological-economic multispecies optimization model, we assess the future stock status under different scenarios of change. We simulate (i) technological progress in fishing, (ii) increasing demand for fish, and (iii) increasing supply of farmed fish, as well as the interplay of these driving forces under different scenarios of (limited) fishery management effectiveness. We find that economic change has a substantial effect on fish populations. Increasing aquaculture production can dampen the fishing pressure on wild stocks, but this effect is likely to be overwhelmed by increasing demand and technological progress, both increasing fishing pressure. The only solution to avoid collapse of the majority of stocks is institutional change to improve management effectiveness significantly above the current state. We conclude that full recognition of economic drivers of change will be needed to successfully develop an integrated ecosystem management and to sustain the wild fish stocks until 2048 and beyond.

Organochlorine contaminants in different tissues from Platichthys flesus (Pisces, Pleuronectidea).

Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) are organic contaminants that tend to accumulate in fish. Estuaries are exposed to high anthropogenic activities, therefore tending to accumulate more contaminants than the adjacent coastal waters. Platichthys flesus, a fish with high economic value, was analysed for PCBs and HCB along its different age groups, in liver, gills, gonads and muscle. Younger fishes were caught in the estuary, whereas older fishes were caught in the adjacent coastal waters and acquired at Figueira da Foz Regional Office of Docapesca-Portos e Lotas, SA. Both contaminants concentrations follow the pattern: liver>gills>muscle. Hepatosomatic index had the lowest values in younger fishes and the highest values in older fishes. Condition factor values remain stable with age. Younger fishes had higher PCBs concentrations than the older fishes. In opposition HCB was only detected in fish from 3+ to 5+ and its concentration tended to increase with age. Overall P. flesus is considered safe for human intake.

Incidencia de histamina y de bacterias indicadoras de calidad higiénica, en filetes, ruedas y trozos de pescado de especies pelágicas comercializadas en un mercado de pescado de la isla de Margarita (Venezuela) / Incidence histamine and hygienic quality indicators´s bacteria in fillets, slice and pieces pelagic fish´s marketing in one fish´s market of Margarita´s Island (Venezuela)

Se estudió la incidencia de histamina y de bacterias indicadoras de manejo higiénico en filetes, ruedas y trozos de diez especies de pescado en estado fresco, (Euthynnus alletteratus; Caranx latus; Ophisthonema oglinum; Alectis crinitus; Sardinella aurita; Thunnus alalunga; Sarda sarda; Scomberomorus cavalla; Coryphaena hippurus y Xyphias gladius), comercializadas en un mercado de pescado de Isla de Margarita (Venezuela). Según normas COVENIN se enumeraron (UFC g-1) aerobios a 25 y 32 °C, coliformes fecales y Escherichia coli (NMP g-1); histamina (mg/100 g) y pH. También recuentos (UFC g-1) de enterobacterias (ICMSF) y bacterias descarboxiladoras de histidina (Niven y otros). Todos los recuentos de aerobios a 25 °C excedieron el valor m (Log10 = 5,70 UFC g-1) fijado por ICMSF (1986). La prueba r de Pearson indicó que los recuentos a 25 y 32 °C estuvieron altamente relacionados (n = 90; r = 0,89; p < 0,01). E. coli superó en el 76% de las muestras el valor m (Log10 = 1,04 NMP g-1). Las mayores cifras de histamina se detectaron en T. alalunga (promedio 43,5 mg/100 g en uno de tres muestreos); seguido por S. aurita (promedios de 23,7 y 28,0 mg/100 g respectivamente, en dos muestreos). Sólo en muestras de T. alalunga se detectaron olores penetrantes y músculos con elasticidad disminuida. Estos datos y la observación de factores adversos, tales como contacto directo con superficies y utensilios sucios, restos de vísceras, desangrado deficiente, presencia de insectos, utilización de agua no potable y la exposición a temperaturas no apropiadas, reflejan que la manipulación del pescado no fue adecuada. Se recomienda que inspectores sanitarios implementen acciones tendentes a corregir estas deficiencias.

The incidence of histamine and of bacteria that indicate hygienic handling of fillets, slices and pieces of ten pelagic fresh fish (Euthynnus alletteratus; Caranx latus; Ophisthonema oglinum; Alectis crinitus; Sardinella aurita; Thunnus alalunga; Sarda sarda; Scomberomorus cavalla; Coryphaena hippurus and Xyphias gladius), sold in a fish market at Margarita Island (Venezuela) was assessed. According to COVENIN´s norms, total aerobic plate count (FCU g-1) at 25 and 32 °C; fecal coliforms and Escherichia coli (MPN g-1); histamine (mg/100 g) and pH were measured. Also, members of the Enterobacteriaceae family (FCU g-1) and histamine producing bacteria were counted, according to ICMSF and Niven et al respectively. All total aerobic plate count at 25 °C surpassed the m number (Log10 = 5.70 CFU g-1) established by ICMSF (1986). The Pearson test (r) showed that bacteria total counts at 25 and 32 °C were highly related (n = 90; r = 0.89; p < 0.01). E. coli exceeded in 76% of samples the number (Log10 = 1.04 MPN g-1). Histamine biggest numbers were detected in T. alalunga (average 43.5 mg/100 g in one of three samplings), followed by S. aurita (averages of 23.7 and 28.0 mg/100 g respectively, in two samplings). Only in T. alalunga samples were penetrating odors detected and muscles with reduced elasticity. This data and the adverse factors observed, such as: fish in direct contact with dirty areas and utensils, leftover viscera, faulty bleeding, presence of insects, use of non potable water and the exposition of fish at inappropriate temperatures, revealed the handling of fish was not suitable. It is recommended that sanitary officers carry out actions necessary to correct these deficiencies.