Horse Mackerel Research Articles

Seabird distribution is better predicted by abundance of prey than oceanography. A case study in the Gulf of Cadiz (SW, Iberian Peninsula)

AbstractQuantifying factors that influence marine predator distributions is essential to understanding the current and future change in marine biodiversity. Here, we test whether marine predator distribution relates to prey, or is better predicted by other specific habitat features. We examine the correlation between spatial distribution of three seabird species and their prey, as well as environmental proxies (oceanographic characteristics) in the Gulf of Cadiz, NE Atlantic. We modeled the at-sea distribution of Cory's shearwater, Balearic shearwater and Northern gannet, based on: (i) pelagic fish abundance according to acoustic surveys, and (ii) a forecast-model of remotely sensed environmental variables (productivity, sea surface temperature, and salinity). In general, seabird distributions were better predicted by abundance of fish than by environmental variables at the habitat scale. We obtained consistent correlations between seabird presence and the abundance of medium-sized (10–20 cm) sardines, anchovies and Mediterranean horse mackerel, providing information on their preferred prey. Additionally, oceanographic productivity variables moderately contributed to seabird distribution models, with better predictive value for the critically endangered Balearic shearwater and Northern gannet in the summer, whilst the model for Cory's shearwater's produced poorer predictions. Predator–prey combined studies may represent essential tools for an efficient ecosystem-based management of marine environments.

Suspected microplastics in Atlantic horse mackerel fish (Trachurus trachurus) captured in Portugal

Microplastics have been found in fish, but most studies have focused on the digestive system without considering additional organs. Herein, the objective was to assess the presence of microplastics in internal organs (gills, guts, kidney, heart) of the Atlantic horse mackerel (Trachurus trachurus) captured of the coast of Portugal (Northeast Atlantic Ocean). Suspected microplastics were present in all organs, with particles of larger size (i.e., equivalent diameter) found in the gut and those of lower size in the heart and its luminal blood. Suspected microplastics of 1–10 μm were the most abundant (65.4%), more likely to translocate, owing to their minute size, but more difficult to properly characterize. These results highlight the need to expand the analytical work on organs and tissues for assessing microplastics in organisms, but also emphasize the actual need for developing analytical methods that allow for an accurate isolation, identification, and characterization of microplastics in biota.

Exploring the mechanics of fish escape attempts through mesh

Predictive selectivity modelling is used to study fishing gear selectivity. These models rely on fish morphology parameters and fall-through experiments. Here, we developed a model of the mechanical interaction between a fish and a netting mesh during an escape attempt. In this model, the fish is described with three parameters: the first parameter measures its mechanical ability to penetrate a mesh and the others are body stiffness coefficients accounting for fish body deformation under mesh twine pressure. These parameters were identified from the results of a bench test simulating a fall-through experiment through a single 60-mm Polyethylene (PE) mesh. A rigid circular cone, a rigid elliptical cone and a small number of horse mackerel and haddock, offering a limited length range, were tested. Results were generalised and compared with those obtained on a piece of netting. Within the model's assumptions, it is possible to predict the success of an escape attempt if one knows the three fish parameters and the mesh load in normal and transverse directions. The study showed that escape potential is greater through an actual deformable mesh than through a non-deformable mesh. The potential size of this difference depends on the mesh load and orientation.

Effect of smoking on the microbiological quality of horse mackerel (Trachurus trachurus) processed and marketed by artisanal fishermen from Vilankulos, Mozambique

Smoking is one of the fish conservation techniques used by some artisanal fishing communities. Horse mackerel is a fish widely traded and consumed in Mozambique. This study aimed to evaluate the effect of smoking on the microbiological quality of horse mackerel sold in district Desse in Vilankulos. Twelve samples were collected and analyzed for following microbiological parameters (total viable microorganisms, total coliforms, thermotolerant coliforms, Escherichia coli, Salmonella spp., Staphylococcos aureus, Vibrio cholerae and Vibrio parahaemolyticus). The total viable microorganisms were quantified by the NMKL method and the total coliforms, fecal coliforms, and Escherichia coli were quantified by the MPN method. Statistical analysis were performed using the SPSS program, and data were submitted to the normality test using the Shapiro-Wilk test at a significance level of 5%. The results showed the existence of significant differences in the amount of aerobic microorganisms between frozen horse mackerel (3.59 ± 0.87 CFU/g) and smoked horse mackerel (2.39 ± 0.88 CFU/g), total coliforms (0.22 ± 0.53 CFU/g), and (0.06 ± 0.19 CFU/g), respectively, and thermotolerant coliforms (0.12 ± 0.25 CFU/g) and (0.06 ± 0.19 CFU/g), respectively. Smoked horse mackerel had less contamination compared to the frozen fish. There was no significant growth of other microorganisms analyzed.

Predatory species left stranded following the collapse of the sardine Sardinops sagax (Pappe, 1854) stock off the northern Benguela upwelling system: A review

Sardine Sardinops sagax (Pappe, 1854) is an important forage species, in the northern Benguela Upwelling System (nBUS). Sardine was a key forage species of the pelagic component in the nBUS, but the population collapsed due to a combination of overfishing and ecosystem change and variability in the nBUS. Multiple predators depended on sardine as high-quality food at the time when it was abundant. This study reviewed the current knowledge of predators' diet pre- and post-collapse of the sardine population stock in the nBUS. Data were sourced from previous studies on the trophic interaction in the nBUS. The historical and contemporary diets of commercially exploited species that prey on sardine were found to be relatively well documented while there are data deficiencies for non-commercially exploited species including cetaceans, sharks and some non-commercially exploited fish species. Amongst the species most reliant on sardine as prey are African penguin Spheniscus demersus, Cape gannet Morus capensis, Cape cormorant Phalacrocorax capensis, Cape monkfish Lophius vomerinus, shallow-water hake Merluccius capensis, deep-water hake M. paradoxus, snoek Thyrsites atun, Albacore tuna Thunnus alalunga, Cape fur seal Arctocephalus pusillus, Common dolphins Delphinus delphis, Dusky dolphins Lagenorhynchus obscurus, Heaviside's dolphins Cephalorhynchus heavisidii, six gills shark Hexanchus griseus, copper sharks Carcharhinus brachyurus, school shark Galeorhinus galeus and pelagic sharks Prionace glauca. Some predatory species such as the African penguin, Cape cormorant, Cape gannet, and school shark, are considered endangered as per the International Union for the Conservation of Nature (IUCN) Red List criteria. Populations of Albacore tuna and Cape monkfish are near threatened, while Cape fur seals, common dolphins, and shallow-water hake are considered the least concerned on the IUCN list. Although the collapse of sardine has affected the food webs it has not resulted in collapse, rather there have been changes. Three prey species; bearded goby, Cape horse mackerel, and jellyfish, were identified as alternative prey for some of the predators that previously fed on sardine. This review showed how overexploitation of sardine could have had far-reaching effects on the nBUS through feeding linkages. Goby, although a low-quality prey, is a successful substitute for sardine probably mostly due to its high abundance, tolerance to low oxygen and ability to thrive in warm waters. However, further studies are needed to establish the strength of the ecological linkages of the prey species that replaced sardine in the diets of the predators.

Seasonal variation in fish school spatial distribution and abundance under the Kuroshio regular pattern and the large meander in Suzu coastal waters

The Kuroshio Current can take two paths; usually it follows the regular pattern but occasionally it follows a pattern known as the large meander. In this study, we investigated the abundance of fish that migrate to coastal waters and the spatial distribution of fish schools under both Kuroshio patterns in Suzu district, Kochi prefecture, where the set net is the main fishery industry. We clarified the seasonal variation in the density and distribution of fish schools using a quantitative echo sounder. The effects of the Kuroshio large meander (LM) depended on the season. There was no effect of current pattern in summer or autumn, but in winter and spring the LM altered the marine environment and fish distributions. Cold water masses were formed in the survey area during winter and spring during the LM, and the water temperature dropped significantly compared with during the Kuroshio non-large meander (NLM). This altered the fish species and the distribution of fish schools in the survey area. The catches of Japanese horse mackerels (Trachurus japonicus) and Yellowtails (Seriola quinqueradiata) were much higher during the LM compared with those during the NLM. Unlike these two species, the small-sized pelagic fishes in spring has decreased significantly during the LM.

Structure and functioning of the Bay of Biscay ecosystem: A trophic modelling approach

Characterizing the structure and functioning of marine ecosystems requires a deep understanding of the dynamics of its populations and the biotic interactions among them. To this end, we developed a mass-balanced food-web model of a regional sea in the Northeast Atlantic, the Bay of Biscay (BoB), considering one of the most important anthropogenic disturbance in the area, the fishing pressure.The food-web model was performed for the whole BoB region for the first time. The model represents the ecosystems in the early 2000s, encompassing 120433 km2 between 0 and 1000 m depth. The model was composed of 52 functional groups, ranging from primary producers to top predators, and considering both Spanish and French fishing fleets. Input data included biomass obtained locally from bottom trawl and acoustic surveys, data from stock assessment, official fishery statistics, published and unpublished data on stomach content analyses and the use of empirical equations to estimate consumption and production rates.Our results highlight the importance of the pelagic domain, since the main trophic flows are determined by the interaction between phytoplankton, zooplankton and forage fishes. The role of the detritivore pathway was also relevant due to the relatively high abundance of detritivores organisms and the large percentage of primary production flowing to the detritus. Forage fish have resulted to be a key compartment fostering the connectivity between the benthic and pelagic domains. Pelagic sharks, dolphins, anglerfish, large hake and large demersal fishes were identified as potential keystone functional groups in the BoB model. The results also showed an intense exploitation by fisheries in early 2000s. Different strategies between Spanish and French fleets were also found. French fleets were mainly focussed on low trophic level forage fish (e.g., sardine and anchovy) and had larger impacts on higher trophic levels, while Spanish fleets mostly focussed on higher trophic level forage fishes (e.g., mackerel, horse mackerel and blue whiting) but also targeting sardine and anchovy; and displayed lower impacts on higher trophic levels. Overall, our model demonstrates the importance of combining data sources from different countries to regionally address the sought-after implementation of the ecosystem-based management approach.

Understanding the Dynamics of Ancillary Pelagic Species in the Adriatic Sea

The status of fishery resources in the Mediterranean Sea is critical: most of the fish and shellfish stocks are in overexploitation and only half of them are routinely assessed. This manuscript presents the use of Surplus Production Models (SPMs) as a valid option to increase the number of assessed stocks, with specific attention to the Adriatic basin. Particularly, the stock of European sprat (Sprattus sprattus), Mediterranean horse mackerel (Trachurus mediterraneus), and Atlantic horse mackerel (Trachurus trachurus) living in the Adriatic Sea have been evaluated comparing three SPMs: Catch Maximum Sustainable Yields (CMSY), Stochastic surplus Production model in Continuous Time (SPiCT), and Abundance Maximum Sustainable Yields (AMSY). The different approaches present some variations; however, they generally agree on describing all the stocks close to the reference values for both biomass and fishing mortality in the most recent year. For the European sprat, AMSY results are the most robust model for this species’ survey data allow depicting a clearer picture of the history of this stock. Indeed, for the horse mackerel species, CMSY or SPiCT results are the preferred models, since for these species landings are not negligible. Notwithstanding, age-structured assessments remain the most powerful approach for evaluating the status of resources, but SPMs have proved to be a powerful tool in a data-limited context.

How is artificial lighting affecting the catches in deep water rose shrimp trawl fishery of the Central Mediterranean Sea?

The effect of artificial lights mounted on the headrope trawl net on the catch of deep water rose shrimp (Parapenaeus longirostris), European hake (Merluccius merluccius), and Atlantic horse mackerel (Trachurus trachurus) was tested in a survey carried out on-board a commercial trawler off the SW Sicilian coast. A total of 18 repeated nocturnal hauls, alternating without (control) and with (test) LED lights (10 green and 10 white) according to the fishers’ setup, were conducted. Overall, the test net catch rates were not significantly higher than those of the control net (Kruskal-Wallis test, p > 0.05), except for P. longirostris (p < 0.05). Conversely, the two-tailed Kolmogorov–Smirnov test revealed statistical differences in the size structure of P. longirostris, M. merluccius, and T. trachurus between the test and control nets (p < 0.05). Using generalised linear mixed models, the test net was found to yield higher catches of undersized individuals of the three species and adults of P. longirostris than the control net. Our study results are discussed in the context of the exploitation and management of Mediterranean trawl fisheries.

Vibrio vulnificus infection in horse mackerel (Trachurus mediterraneus) and its characteristic symptoms: An experimental study

In the present study, the mortality and characteristic symptoms (bilateral exophthalmia and skin lesions) associated with Vibrio vulnificus infection in horse mackerel (Trachurus mediterraneus) are presented from an experimental infection trial.

Evaluation of the Physico-Chemical Characteristics and Sensory Qualities of Mackerel and Horse Mackerel Smoked with Fruit Peels and Rice Husk Residues in Benin

ABSTRACT Smoked fish quality depends on the fuel used for smoking. This study aimed to improve smoked fish quality using fruit peels, rice husks, and palm kernel charcoal (PCH) as fuels. Thirty fish (15 Atlantic mackerel and 15 horse mackerel) were smoked traditionally, while 75 horse mackerel and 75 Atlantic mackerel were smoked with experimental fuels. Physico-chemical characteristics and sensory quality of the smoked fish were assessed. The highest weight loss after smoking was found for the fish smoked with pineapple skin (32.79%), peanut shells (30.06%), and orange peel (29.84). The skin color of the fish smoked with rice husks was less white, redder, and more yellowish than the other fish. Those smoked traditionally had darker skin. The sensory quality of the fish smoked with rice husks, pineapple skin, and peanut shells was more acceptable. In summary, these fuels can be used to improve the appearance and quality of smoked products.

Lifelong mercury bioaccumulation in Atlantic horse mackerel (Trachurus trachurus) and the potential risks to human consumption

Atlantic horse mackerel is one of the most commercially important species in Europe. It can reach a longevity of 30 years, with potential implications in lifespan mercury contamination. This study conducted along the Portuguese coast aimed at evaluating the total Hg content and tissue distribution, to determine the annual mercury bioaccumulation patterns and the associated risk for consumption. The T-Hg accumulation patterns observed followed the order: muscle (0.34) > liver (0.28) > heart (0.19) > gills (0.11) > brain (0.041 mg kg−1). Significant differences between tissues reflect the role of the different tissues in storage and redistribution. Significant relationships observed between age and T-Hg for all tissues highlight the continuous nature of the bioaccumulation process. European food safety guidelines signalled significant risk of consumption in about 30% of the samples. Still, there was an overall low risk from the consumption of this species, which can be further minimized through consumer options to avoid health issues.

Designing of specialized fish food products with a reduced content of nitrogen extractives

The authors consider the possibility of using low-value pelagic fish species in the diet of people with restrictions on the consumption of nitrogenous extractive substances including nucleic acids which are sources of purine base metabolism. The objects of the study were chopped mackerel fillets from boiled fish and chopped boiled fillets from raw fish, quick-frozen minced horse mackerel of industrial processing in a boiled form. The studies were carried out in accordance with the experimental plan in which the duration of the heat treatment and the temperature of the cooking medium were the variable factors. The technology of combined fish masses with the addition of functional plant components has been proposed. It has been established that the dynamics of dry matter losses and heat losses of fish fillets is determined by the duration of cooking. In terms of organoleptic characteristics boiled minced meat from raw mackerel fillets is significantly inferior to the organoleptic characteristics of minced meat from pre-boiled fillets. When comparing the data for frozen and freshly prepared mince from horse mackerel, it has been found that the loss of nucleic acids in industrially prepared minced meat is 4.6-13.1 % higher ( T = 82 ± 2 and 98 ± 2 °C), the loss of nucleic acids by absolutely dry matter is higher by 11.3-5.8 %, mass - by 8.4-14.6 %. The content of the total amount of nucleic acids in industrial minced meat is 11.1 % lower than in freshly prepared minced meat. Obviously, in the process of preparing products for specialized purposes, including for preventive nutrition, it is preferable to use minced meat from boiled fish fillets.

Fishing under climate change: Dynamics of composition and structure of catches in the Russian Black Sea in the XXI century

Currently, the Black Sea ecosystem is undergoing significant changes, and that affects the dynamics of the species composition of catches. The main reasons for the change in the Black Sea ichthyofauna are considered to be: fishing, anthropogenic water pollution, invasion of new species, and the effect of large-scale climatic and related oceanological and hydrological processes on the productivity characteristics of commercial Black Sea fish. With no understanding the patterns of the effect of these factors on ichthyofauna, it is impossible to rationally use bioresources and protect nature. The aim of the work was to study the effect of climate warming on the species composition and structure of catches in the Russian Black Sea in the XXI century. The authors had used: the results of own ichthyological observations; data published on the composition of the Black Sea catches; and the information available on the official websites of the Ministry of Agriculture of the Russian Federation, the Federal Agency for Fishery, and its Sea of Azov – Black Sea Territorial Administration. The analysis of the possible effect of global warming on the results of fishing in the Russian Black Sea was carried out. It is shown that in the XXI century, the ratio of thermophilic fish, which spawn in the summer, increased; those species are European anchovy Engraulis encrasicolus (Linnaeus, 1758), red mullet Mullus barbatus Linnaeus, 1758, and horse mackerel Trachurus mediterraneus (Steindachner, 1868). As established, the dynamics of the ichthyofauna in the area is determined by at least four processes related to water warming: improvement of reproduction conditions and increased survival of eggs and juveniles of thermophilic species; change in the intraspecific structure; invasion and naturalization of Mediterranean species with the subsequent change in the food relationships within the ecosystem; and concentration of psychrophilic species at greater depths. The need for a thorough study of this issue is concluded, aimed at long-term forecasting of the raw material base state of the fishing industry in the Russian Black Sea.

Balıkçılık ve su ürünlerinin Türk dış ticaretine katkısı: Hibrit çok kriterli karar verme yöntemi ile bir değerlendirme

Fisheries and aquaculture industry, which provides a continuous and high-return market advantage to potential countries, is also one of the priority industries for Turkey. Although Turkey has important advantages with its geographic position and bio-diversity, the industry's contribution to foreign trade is not at an acceptable level. Accordingly, it is important to evaluate the capture fishery and aquaculture products, which provide the best contribution to the foreign trade of Turkey. Thus, the present paper aims to provide foreign trade executives with an intuition about the most appropriate products to invest in and contributing products to Turkish foreign trade within the scope of market strategies. Entropy-WASPAS, which is a hybrid multi-criteria decision-making method, is used for evaluating the contribution of fishery and aquaculture products to Turkish foreign trade. This model includes both criteria (production, import quantity, import value, export quantity, export value) and alternatives (trout, sea bream, sea bass, sprat, atlantic bonito, anchovy, horse mackerel, pilchard, sea snail, prawn, cuttle fish, mussel). Entropy is used to determine the criteria weights, and WASPAS is applied for ranking the fishery and aquaculture products. According to the results, export value is the most important criteria while Sea Bream is found as the most significant product for Turkey’s foreign trade.

Enhancing sunflower oil by the addition of commercial thyme and rosemary essential oils: The effect on lipid quality of Mediterranean horse mackerel and anchovy during traditional pan-frying

The effect of sunflower oil treated with varying proportions of rosemary and thyme essential oils (0.3%, 0.6%, 0.9%, and 1.2%) on the lipid quality of Mediterranean horse mackerel and anchovy during traditional pan-frying was assessed in this research. Concentrations of rosemary and thyme essential oils greater than 0.9% applied to sunflower oil tend to reduce the lipid content of horse mackerel, while anchovies fried in sunflower oil with only a few concentrations of rosemary essential oil seemed to avoid a rise in lipid content that leads to frying. The addition of thyme and rosemary essential oils with the different percentages in frying oil significantly caused a reduction in the peroxide and thiobarbituric acid values of all fish samples after pan-frying (p < 0.05). However, the free fatty acid contents of all fried fish samples did not change significantly by the addition of EOs to sunflower oil (p > 0.05). According to our results, the amount of EPA and DHA in Mediterranean horse mackerel during traditional pan-frying was affected by the type of essential oils and their concentration in sunflower oil. Using EOs at different concentrations, on the other hand, has no noticeable impact on the retention of highly unsaturated fatty acids in anchovies. It shows that all of the essential oils used significantly reduce lipid oxidation and protect against EPA and DHA reduction as a result of frying in Mediterranean horse mackerel.

Observations on the trophodynamics of sawtooth barracuda,Sphyraena putnamaefrom the Bay of Bengal, northern Indian Ocean

AbstractMarine capture ofSphyraena putnamaealong western Bay of Bengal has been increasing. Owing to scarcity of information available on feeding dynamics globally, the present study was conducted using 763 individuals captured during 2017–19, to decipher trophic ecology and relationships. Of the individuals analysed, 54.8% had their stomachs either empty or with trace amounts of food, 27.3% had part-full stomachs and 18.0% had full stomachs. Stomach vacuity and fullness as well as predator–prey weight ratio varied with increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was highest during July–November and lowest during March–April. The species is an opportunistic piscivorous pelagic predator that feeds on teleosts (&gt;85%) and cephalopods. Sardines were the major prey, followed by whitebait, squid, bigeye scad, Indian scad, silverbellies and Indian mackerel. Diet contents were similar between sexes (82.17%); however, it varied among seasons (56.86–69.85%). Shifts in prey preferences from sardines, squid and bigeye scad to ribbonfish, shad, grunter, Indian mackerel, horse mackerel andAceteswere observed with increase in fish size, and diet varied between individuals sized &lt;60.0 and &gt;60.0 cm. Trophic level value was 3.51 ± 0.13 and Levin's Standardized Niche Breadth Index was 0.21. Dietary niche breadth varied across seasons and sizes, with higher values during summer and winter (0.36–0.41) and in fish measuring &gt;45.0 cm (0.50–0.68), which implies generalized feeding behaviour. The present study represents the first detailed report on the diet ofS. putnamaeand will provide a substantial contribution to stock management through understanding of trophic interactions.

Human health risks and benefits assessment based on OCPs, PCBs, toxic elements and fatty acids in the pelagic fish species from the Adriatic Sea

Benefits and risks of the fish consumption should be assessed to balance the ingestion of healthy omega-3 fatty acids and adverse chemicals. Persistent organic pollutants-POPs (organochlorine pesticides-OCPs and polychlorinated biphenyls-PCB), macro- and micro-elements and fatty acid contents were determined in six fish species from the Adriatic Sea to assess health risks for consumers (worst-case scenario, diseases development risks and benefit-risk). 16 element, 24 POPs and 14 fatty acid contents were determined in six pelagic species which can be used in human diet. Element concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS), POPs by high-resolution gas chromatography and fatty acid content by gas–liquid chromatography. Diet based on chub mackerel and round sardinella showed lower daily intake (DI) of POPs and highest DI of essential omega-3 fatty acids than other investigated species. Lower ingestion of toxic elements can be observed by consuming anchovy and round sardinella. Based on POP concentrations, there was not observed non-carcinogenic (HI) nor carcinogenic (CR) risks for consumers. Based on element concentrations, there was low HI (0.1 ≥ HI ≥ 1), while the maximum HIs and outlier values (horse mackerel and anchovy samples) implied the presence of HI (HI > 1). The most significant contributor to total non-carcinogenic and carcinogenic risks was inorganic arsenic (inorganic As). Acceptable CR for consumers was assessed, but maximum CR for consumers of horse mackerel and anchovy (CR ≥ 1 × 10–6) showed adverse effects on human health. There were low HIs for developing cardiovascular, nervous, and reproductive diseases, and maximum HIs were higher than 1. Acceptable (1 × 10−4≥CR ≥ 1 × 10−6) risks were observed for developing cancer of nervous system and reproductive organs. Among investigated fish samples, those with higher ƩBR (benefit-risks) and BR for arsenic (As) than median value have a higher risk than benefits in the human diet.

Microbial Assessment and Health Risks of Consumption of Uncooked Smoked Horse Mackerel Fish (Trachurus trachurus) Sold in Open Markets in Owerri Metropolis, South Eastern Nigeria

Aim: To assess the microbiological quality of uncooked smoked horse mackerel fish (Trachurus trachurus) sold in Owerri and ascertain the presence and prevalence of microorganisms of public health importance.&#x0D; Study Design: Random sampling was done.&#x0D; Place and Duration of Study: Department of Microbiology, Federal University of Technology, Owerri; from October, 2019 to April, 2020.&#x0D; Methodology: Smoked fish samples (n=20) were purchased randomly from retailers in Relief, Naze, Eziobodo and Obinze markets and taken to the laboratory for isolation and identification of microorganisms. Standard microbiological methods were employed to analyze for viable heterotrophic bacterial and fungal counts on nutrient agar and potato dextrose agar respectively, using the spread and streak plate techniques. Coliform counts were done on MacConkey agar. Biochemical characterization of the microorganisms was adopted for their identification.&#x0D; Results: Bacteria identified included Staphylococcus, Escherichia, Proteus, Salmonella and Micrococcus species. Total heterotrophic bacterial counts and coliform counts ranged from 2.8 x 106 cfu/g to 1.6 x 108 cfu/g and 2.7 x 104 cfu/g to 5.3 x 105 cfu/g respectively. Fungal species identified were Penicillium, Rhizopus, Mucor, Aspergillus and Fusarium spp and fungal counts as high as 4.5 x 105 cfu/g were recorded.&#x0D; Conclusion: The high level of microbial contamination of the samples and the presence of organisms of public health importance signifies an obvious danger to human health. Eating smoked fish without proper cooking should be discouraged by the relevant authorities. Also, food safety authorities should intensify their monitoring efforts towards controlling such contaminations and averting possible outbreaks of diseases.

Characteristics of fish-bone foreign bodies in the upper aero-digestive tract: The importance of identifying the species of fish.

BackgroundFish bones are common foreign bodies in the upper aero-digestive tract, but their clinical features in relation to fish species have not been confirmed. We aimed to clarify the clinical characteristics of fish-bone foreign bodies and their location and removal methods depending on the fish species.Study designRetrospective, observational, monocentric study.MethodsFrom October 2015 to May 2020, 368 patients visited the Department of Otolaryngology-Head and Neck Surgery at Tohoku University Hospital complaining of dysphagia, sore throat, or pharyngeal discomfort after eating fish. We analyzed the patients’ sex and age distribution, foreign-body location, type of the fish, and the techniques used for removing the foreign body.ResultsFish bones were confirmed in the upper aero-digestive tract in 270 cases (73.4%), of which 236 (87.4%) involved fish-bone foreign bodies in the mesopharynx. The most frequently involved site was the palatine tonsil (n = 170). Eel was the most frequently observed fish species (n = 39), followed by mackerel (n = 33), salmon (n = 33), horse mackerel (n = 30), and flounder (n = 30). Among the 240 cases in which the bones did not spontaneously dislocate, 109 (45.4%) were treated by endoscopic removal (103 cases) or surgery (6 cases). In pediatric cases (<12 years old), almost all fish bones were found in the mesopharynx (138/139, 99.3%), and 31 cases (22.3%) required endoscopic removal. Flounder fish bones were often lodged in the hypopharynx and esophagus (9/30, 30%), hindering spontaneous dislocation and frequently necessitating endoscopic or surgical removal (19/29, 65.5%).ConclusionThe characteristics of fish-bone foreign bodies differed depending on the fish species. Flounder bones were often stuck in the hypopharynx and esophagus and were likely to require more invasive removal methods. Confirming the species of the fish could facilitate appropriate diagnosis and treatment of fish-bone foreign bodies.