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The mean weight-at-age of fish species is an indicator of fish growth and physiological condition, as well as a basic parameter for assessing and managing fish stocks. Here, we investigate the temporal trends of the mean weight-at-age of four different commercial species with different life strategies: (i) the short-lived pelagic European sardine (Sardina pilchardus), (ii) the horse mackerel (Trachurus trachurus) and two medium-lived benthic, (iii) the megrim (Lepidorhombus whiffiagonis) and iv) the four-spotted megrim (Lepidorhombus boscii), in North Atlantic Iberian waters from 2000 to 2018. Generalised additive models were implemented to identify the main (density-dependent and density-independent) drivers of fish weight-at-age variability: abundance, sex, maturity, sea surface temperature, sea bottom temperature, North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation indices. In all four species, abundance had a negative effect on mean weight-at-age. Temperature affected mean weight-at-age in sardine and megrim, while NAO influenced it in horse mackerel and four-spotted megrim. In the case of the sardine, we observed a progressive decrease in the mean weight-at-age of adults in the series in contrast to the four-spotted megrim; however, there was no effect of year on either horse mackerel or megrim. We discuss the influence of life strategy on fish response to drivers. [ABSTRACT FROM AUTHOR]

The present study focuses on the detailed description of postovulatory follicles (POFs) resorption and atresia in horse mackerel from Algerian waters. From February 2013 to February 2014, 155 female horse mackerel were randomly collected. Histological sections of ovaries were analyzed. Few POFs (7.28% of early POFs and 2.91% of old POFs of the total observed oocytes) were detected. Morphological changes of POF resorption were discussed in the current study. No particular shape was observed. Four types of atretic oocytes were determined: α = 34.38%, β = 5.28%, δ = 2.37% and γ = 0.94%, which was reported for the first time in horse mackerel. The incidence of α atresia was higher in the yolked (21.48%) than in the unyolked oocytes (12.89%). α atretic oocytes can be classified into two main types: non-bursting (capsulated, lipoidal and cystic atresia) and bursting (multiple bursts, single bursts, phagocytic bursts and liquified bursts). Further studies are required to better understand the reproductive strategies of fish in relation to postovulatory follicle resorption and atresia.

Background: Parvalbumin Gad c1 is a major cod allergen used as a follow‐up marker of fish‐allergic children. However, the diagnostic efficacy of recombinant Gad c 1 (rGad c 1) for fish allergy diagnosis remains controversial. This study aimed to evaluate the efficacy of rGad c1 for diagnosing cod and horse mackerel allergy. Methods: This single‐centered, retrospective study obtained oral food challenges (OFCs) information performed for cod and horse mackerel. Cod‐, horse mackerel‐, and rGad c1‐specific immunoglobulins (sIgEs) were investigated. Diagnostic performances of these parameters were compared using areas under the curve (AUC). Results: We enrolled 45 and 38 children with suspected cod and horse mackerel allergies, respectively. The median age (interquartile range) of children with suspected cod allergy was 5.7 (0.7–11.7) years and that of children with suspected horse mackerel allergy was 6.0 (1.0–12.3) years. Fourteen and 22 children reacted to OFCs with 25 (10–40) g of cooked pacific cod and 40 (10–40) g of cooked horse mackerel, respectively. The cod sIgE and rGad c 1 sIgE AUCs for cod allergy diagnosis were 0.85 and 0.90, respectively. For horse mackerel allergy diagnosis, AUCs of horse mackerel and rGad c 1 sIgE were 0.76 and 0.72, respectively. Both AUCs for cod and mackerel allergy were significantly different. Conclusion: rGad c 1 sIgE is more effective than cod sIgE as a diagnostic marker of cod allergy, but less effective than horse mackerel sIgE as a diagnostic marker of horse mackerel allergy. Further studies are warranted to explore the potential applications of rGad c 1 sIgE in the diagnosis of various fish allergies. [ABSTRACT FROM AUTHOR]

Freshness is one of the most important qualities of food products. However, quantifying the welfare value of freshness is challenging because reliable measures of freshness are rarely available for researchers. We overcome this challenge by using a newly developed device that generates objective and continuous measures of freshness via bioimpedance analysis. We sample whole horse mackerel and sardines at randomly selected retail stores in Tokyo, Japan, and examine the consumers' marginal willingness to pay for freshness in the hedonic price framework. By using spatial fixed-effects estimation, we find that the marginal willingness to pay is both statistically and economically significant for horse mackerel, with a one standard deviation increase in freshness leading to a 10.75% increase in price. In contrast, there is no statistically or economically significant freshness premium for sardines. These results are consistent with the dietary habits in Japan; horse mackerel are often eaten raw, while sardines are often eaten cooked. [ABSTRACT FROM AUTHOR]

Hysterothylacium aduncum is a parasitic nematode that infects mainly marine fish. The information on the heterogeneity in the aggregation of macroparasites in fish species is still limited, particularly for the Raphidascarid nematode H. aduncum that infects exploitable marine fish species including horse mackerel (Trachurus trachurus). This study aimed to investigate the heterogeneity of the distribution of H. aduncum to better understand macroparasite aggregation in marine fish. Weibull tests comprising Maximum likelihood were used to analyze the frequency distribution of parasites within a fish host population over the three years period. The parasite, H. aduncum (third larval stage) prevalence was found to be 88% and the condition factor was 1.30∓0.029 in un-infected fish and 1.12∓0.022 in infected fish. The clustered pattern was observed in H. aduncum in horse mackerel. The relation between parasite load and the fish condition factor was found to be significant and conformity of length and weight was affected by parasite load. It is the first time that aggregation has been observed in H. aduncum distribution and forecasts of nematode intensity in horse mackerel. The findings related to the large individual variations suggest that this pattern is significant and should be considered for host-parasite dynamics. [ABSTRACT FROM AUTHOR]

Namibia's population of Cape fur seals Arctocephalus pusillus pusillus is a major constituent of top predator biomass in the northern Benguela upwelling system. Understanding their diet is key to comprehending their role in the ecosystem and potential drivers of recent population changes, such as a northward extension of the population's range. Using prey remnants retrieved from 1 413 scat samples collected monthly at 12 Cape fur seal colonies along the Namibian coast over 28 years (1994-2021), we assessed seasonal and geographical differences in their diet. We include the first comparison of diet between the growing colonies in the far northern area of Namibia and the colonies to the south, many of which have been in decline. Four fish species dominated in the diet. The bearded goby Sufflogobius bibarbatus, which is ubiquitous throughout the northern Benguela ecosystem, was the mostabundant prey item in the diet. However, Cape fur seals appeared to show a preference for the more-nutritious fish species Cape horse mackerel Trachurus capensis and the lanternfish Lampanyctodes hectoris by switching to those prey during autumn and spring in the north and south, respectively, coinciding with the greater availability of those species during upwelling periods. The availability of Cape horse mackerel, especially during a critical period for the growth and development of pups before the onset of winter, may be key to the greater productivity of Cape fur seal colonies in the north relative to those in the south of Namibia, and warrants further investigation. Juveniles of Cape horse mackerel and Cape hake Merluccius capensis were the only fishery species of commercial importance that were relatively abundant in the seals' diet, while the sardine Sardinops sagax, which was historically dominant, was found in negligible proportions. [ABSTRACT FROM AUTHOR]

The combined effects of thermal processing (i.e., sterilisation treatment) and the prior frozen storage time (3 or 6 months at −18 °C) on the quality loss in canned Atlantic horse mackerel (Trachurus trachurus) were determined. Thus, the sterilisation step led to a remarkable (p < 0.05) formation in the canned fish muscle of fluorescent compounds, free fatty acids (FFAs), and trimethylamine and an increase in the L* and b* colour parameters; meanwhile, a decrease (p < 0.05) in the total ω3 FA/total ω6 FA ratio and the a* colour value were detected. The prior frozen storage period led to an increased (p < 0.05) lipid oxidation (peroxide, thiobarbituric acid reactive substance, and fluorescent compound formation) and hydrolysis (FFA formation) development and to increased L* and b* colour values in the corresponding canned samples; additionally, a lower (p < 0.05) polyene index and phospholipid content were observed in canned fish previously subjected to frozen storage. In most indices, physico-chemical changes related to quality loss were found to be higher if the previous storage period was increased. According to the marked effects of the sterilisation step and the prior frozen storage period, the optimisation of such processing conditions is recommended to maximise the quality of canned horse mackerel. [ABSTRACT FROM AUTHOR]

The antioxidant properties of the liquor resulting from commercial octopus cooking were analysed for this study. Two different concentrations of octopus-cooking liquor (OCL) were tested as glazing systems during the frozen storage period (−18 °C for up to 6 months) of whole Atlantic horse mackerel (Trachurus trachurus). Compared to water-control glazing samples, an inhibitory effect (p < 0.05) on lipid oxidation development (the formation of thiobarbituric acid reactive substances and fluorescent compounds) was detected in frozen fish treated with the most concentrated OCL-glazing system. Additionally, a preservative effect (p < 0.05) on polyunsaturated fatty acids (measurement of polyene index) was also proved. However, no effect (p > 0.05) on the free fatty acid content and on the ω3/ω6 ratio was detected with the presence of the OCL in the glazing system. An increased lipid quality in frozen horse mackerel was established by including the OCL solution in the glazing system. According to previous research, the observed preserving properties were explained on the basis of the presence of antioxidant compounds in the cooking liquor. A novel and valuable combination of glazing processing and the employment of a marine waste substrate is proposed to enhance the lipid stability of frozen fish. [ABSTRACT FROM AUTHOR]

Modori-inducing proteinases (MIPs) in horse mackerel and the effect of sodium citrate on the modori phenomenon were investigated. Cysteine protease caused the modori phenomenon only at 60 ℃, while metalloproteinase caused it at both 60 ℃ and 70 ℃. Moreover, the autolysis of myofibrillar proteins was mainly inhibited by ethylene diamine tetra-acetic acid (EDTA), verifying the existence of insoluble metalloproteinase. From the results comparing thermal gel properties and protease activities, we confirmed that increased activity of insoluble metalloproteinase corresponded to the weakening of the thermal gel. Thus, insoluble metalloproteinase was the major MIP in horse mackerel. Moreover, sodium citrate could markedly inhibit insoluble metalloproteinase activity at 60 ℃. The addition of sodium citrate significantly improved the breaking force of the thermal gel at 60 ℃ and 70 ℃, suggesting that sodium citrate could suppress the modori phenomenon by inhibiting insoluble metalloproteinase. Therefore, it is desirable to use sodium citrate in horse mackerel surimi-based products to prevent the modori phenomenon. [ABSTRACT FROM AUTHOR]

The combined effects of thermal processing (i.e., sterilisation treatment) and the prior frozen storage time (3 or 6 months at −18 °C) on the quality loss in canned Atlantic horse mackerel (Trachurus trachurus) were determined. Thus, the sterilisation step led to a remarkable (p < 0.05) formation in the canned fish muscle of fluorescent compounds, free fatty acids (FFAs), and trimethylamine and an increase in the L* and b* colour parameters; meanwhile, a decrease (p < 0.05) in the total ω3 FA/total ω6 FA ratio and the a* colour value were detected. The prior frozen storage period led to an increased (p < 0.05) lipid oxidation (peroxide, thiobarbituric acid reactive substance, and fluorescent compound formation) and hydrolysis (FFA formation) development and to increased L* and b* colour values in the corresponding canned samples; additionally, a lower (p < 0.05) polyene index and phospholipid content were observed in canned fish previously subjected to frozen storage. In most indices, physico-chemical changes related to quality loss were found to be higher if the previous storage period was increased. According to the marked effects of the sterilisation step and the prior frozen storage period, the optimisation of such processing conditions is recommended to maximise the quality of canned horse mackerel.

The effects on lipid damage in canned horse mackerel (Trachurus trachurus) of a prior frozen storage (−18 °C) period and the presence of an octopus (Octopus vulgaris) cooking juice (OCJ) in the packing medium were investigated. An increase of the frozen storage time favoured an increase (p < 0.05) of free fatty acid (FFA), peroxide, and thiobarbituric acid reactive substance contents and a decrease (p < 0.05) of the phospholipid (PL) value and polyene index. Furthermore, an increased presence of OCJ in the packing medium led to an inhibitory effect (p < 0.05) on fluorescent compound formation as well as to a retention (p < 0.05) of the PL and FFA compounds. Colour determination showed a substantial increase (p < 0.05) of L* and b* values in canned fish with previous frozen storage time. Nevertheless, this increase was partly reduced (p < 0.05) by the OCJ presence in the packing medium. It is concluded that previous holding time has led to an increased lipid oxidation development and loss of beneficial lipid constituents (i.e., PLs and polyunsaturated fatty acids). Remarkably, the presence in the packing medium of preservative compounds (i.e., antioxidants) included in waste juice obtained from octopus processing provided an effective tool for lipid preservation and quality enhancement in canned fish. [ABSTRACT FROM AUTHOR]

The antioxidant properties of the liquor resulting from commercial octopus cooking were analysed for this study. Two different concentrations of octopus-cooking liquor (OCL) were tested as glazing systems during the frozen storage period (−18 °C for up to 6 months) of whole Atlantic horse mackerel (Trachurus trachurus). Compared to water-control glazing samples, an inhibitory effect (p < 0.05) on lipid oxidation development (the formation of thiobarbituric acid reactive substances and fluorescent compounds) was detected in frozen fish treated with the most concentrated OCL-glazing system. Additionally, a preservative effect (p < 0.05) on polyunsaturated fatty acids (measurement of polyene index) was also proved. However, no effect (p > 0.05) on the free fatty acid content and on the ω3/ω6 ratio was detected with the presence of the OCL in the glazing system. An increased lipid quality in frozen horse mackerel was established by including the OCL solution in the glazing system. According to previous research, the observed preserving properties were explained on the basis of the presence of antioxidant compounds in the cooking liquor. A novel and valuable combination of glazing processing and the employment of a marine waste substrate is proposed to enhance the lipid stability of frozen fish.

It is supported by studies that heavy metals and other water pollutants can reach humans through the food chain because of accumulation in organs of digestion, respiration, and muscles of fish, and may cause toxic effects depending on the amount of pollution and accumulation. This study was carried out by obtaining Horse mackerel samples from the Çanakkale Strait, which are fish species with high economic and nutritional value, as well as frequently consumed, seasonally (spring, summer, autumn, and winter). In the study, the tissues dissected from the dorsolateral muscles of the fresh fish were taken into Bouin's fixative, and sections were taken after routine histological follow-up. The findings revealed degenerative and inflammatory findings in the muscle tissues of fish caught especially in the autumn season. In addition, a statistically significant difference was found in autumn samples in terms of immunoreactivity (p<0.05). [ABSTRACT FROM AUTHOR]

This study aims to investigate a new method of glazing for improving the storage quality of frozen horse mackerel. Specifically, this study explored the effect of double-glazing with theaflavins on the quality of horse mackerel stored at −20°C for 28 weeks by comparing with unglazed and those single glazed with theaflavins. Chemical indicators were used to assess deterioration during storage, the water-holding capacity (WHC), weight loss, drip loss, and low-field nuclear magnetic resonance (LF-NMR) were used to analyze the water retention of fish and water migration in tissues. The water retention analysis results showed that double-glazing can maintain higher WHC, T22 values and lower weight loss, drip loss, T23 values at the end of storage. Chemical analysis results showed that double-glazing combined with theaflavins was highly effective in maintaining lower TVB-N, FAAs, MDA values, and higher SH, IFI values in frozen horse mackerel, especially theaflavins as inner layer glazed material, perhaps due to the synergistic effect of anti-crushing and antioxidant abilities. Therefore, the double-glazing with TF inner layer was more effective in controlling quality changes of frozen horse mackerel.

The concentration levels of Zn, Pb, Cd and Cu were evaluated in the gonads and fillets of Horse mackerel (Trachurus trachurus) collected from Ghazaouet bay. The results showed the accumulation of Pb, Cd, Cu and Zn in the gonads and fillets. The metal concentrations in the fillets and gonads decreased in the following order: Zn >Cd >Pb >Cu and Zn >Cd >Cu >Pb, respectively. The levels of essential metals (zinc and copper) in both target organs generally complied with the recommended value for fish while the levels of non-essential metals like cadmium and lead, which are toxic and present in traces, greatly exceeded the recommended values in both target organs, which are ascribed mainly to the industrial pollution in Ghazaouet area. Therefore, it can be concluded that these heavy metals in different tissues of Horse mackerel, which is highly consumed in the Algerian coastal regions, could pose adverse health effects on consumers. [ABSTRACT FROM AUTHOR]

Background. Atlantic horse mackerel, Trachurus trachurus (Linnaeus, 1758), is among bento-pelagic species subject to discard within deep-water rose shrimp fisheries, and how such species would react to light wavelength is therefore important, to be consistent with the Common Fishery Policy (CFP). Despite the existing literature currently available, there is still paucity of relevant information about how artificial light wavelengths affects the behaviour of T. trachurus juveniles. In this context, the effects of different artificial light wavelengths on some behavioural features of juvenile T. trachurus were investigated. Materials and methods. Maintained in a fish tank, the juveniles of Atlantic horse mackerel, after acclimatization, were subject to six different light wavelengths, representing the following colours: white, violet, blue, green, yellow, and red. Subsequently, behavioural features, specifically phototaxis (degree of attraction or repulsion toward the light source) were tested. Results. By phototaxis per light wavelength, the studied juvenile individuals produced statistical differences in the presence frequency (P < 0.05) revealed by blue that noticeably attracted some, relative to the white light that repulsed others. Yet, violet and red lights produced much less but no significant attraction of these juveniles (P > 0.05). Conclusion. The presently reported study has provided additional information about ecological knowledge and understanding specific to juvenile T. trachurus individuals, which can further the development of (selective) light fishing techniques, aimed at reducing unwanted catches of commercial pelagic fisheries.

The aim of the present study was to perform a pilot assessment and analysis of the oxidative stress (OS) level in four commercially important fish species (round goby, red mullet, sprat and horse mackerel) from different localities of the Bulgarian Black Sea coast. The fish were sampled during trawl selectivity experiments. The OS level in the fish was assessed by measuring lipid peroxidation (LPO), glutathione concentration (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as acetylcholine esterase (AChE) in gills and liver. Round goby and red mullet caught in the Nessebar Bay showed clear signs of OS with the highest levels of LPO and GST activities, accompanied by the lowest AChE activities in both liver and gills. On the contrary, round goby caught near Maslen Nos (a region with good ecological conditions) were least affected by OS with low LPO and high GSH concentrations and SOD activity. There were no significant differences in the OS bioindicators of horse mackerel from the different localities. Sprat caught in Nessebar Bay, compared to those caught from the other localities, showed presence of OS indicated by lower GSH levels and relatively higher CAT, GPx and GST activities, accompanied by low AChE activity in gills. It can be concluded that round goby and red mullet were more vulnerable to OS induced by marine environmental factors than the horse mackerel and sprat. However, their antioxidant defense system allows them to tolerate and adapt to the environment of their habitats. Further studies are needed for the assessment of OS in important fish species in the Bulgarian part of the Black Sea. [ABSTRACT FROM AUTHOR]

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.

The Marmara Sea is a semi closed fishing area in Turkey and has valuable fish species such as the common sole, black scorpionfish and horse mackerel. Domestic waste, generated by the population of over 25 million living in the coastal zone as well as industrial facilities in the region are the main causes of pollution in the Marmara Sea. In the current study, the levels of toxic metals (arsenic, cadmium, mercury, and lead) in samples of three fish tissue were analysed over a year-long period and compared with international results. The health risks for different age groups caused by the consumption of these fish were estimated. The results revealed that regular weekly consumption of sole and horse mackerel caught from the Marmara Sea posed health risks for child and youth populations. These fish species should be consumed more carefully due to potential arsenic-related hazards and carcinogenic risks for vulnerable consumer groups.

The effects on lipid damage in canned horse mackerel (Trachurus trachurus) of a prior frozen storage (−18 °C) period and the presence of an octopus (Octopus vulgaris) cooking juice (OCJ) in the packing medium were investigated. An increase of the frozen storage time favoured an increase (p < 0.05) of free fatty acid (FFA), peroxide, and thiobarbituric acid reactive substance contents and a decrease (p < 0.05) of the phospholipid (PL) value and polyene index. Furthermore, an increased presence of OCJ in the packing medium led to an inhibitory effect (p < 0.05) on fluorescent compound formation as well as to a retention (p < 0.05) of the PL and FFA compounds. Colour determination showed a substantial increase (p < 0.05) of L* and b* values in canned fish with previous frozen storage time. Nevertheless, this increase was partly reduced (p < 0.05) by the OCJ presence in the packing medium. It is concluded that previous holding time has led to an increased lipid oxidation development and loss of beneficial lipid constituents (i.e., PLs and polyunsaturated fatty acids). Remarkably, the presence in the packing medium of preservative compounds (i.e., antioxidants) included in waste juice obtained from octopus processing provided an effective tool for lipid preservation and quality enhancement in canned fish.

Microplastics (MP) have been confirmed as emerging pollutants in the marine environment due to their ubiquity, bioavailability, persistence and potential toxicity. This study contributes with valuable data regarding the abundance and characteristics of the MP found in five species collected from Portugal. The mussel Mytilus galloprovincialis (n = 140) was collected from the Tagus estuary and Porto Covo coastal area, the peppery furrow shell Scrobicularia plana (n = 140) and the polychaete Marphysa sanguinea (n = 30) both from the Sado estuary, and Trachurus trachurus (n = 82) and Scomber colias (n = 82) fished off Figueira da Foz and Sesimbra. Soft tissues of all individuals were digested using a KOH (10%) solution, which allowed the extraction of MP. All studied species presented MP. In a total of 502 MP observed from all samples, 80% were fibers and 20% were fragments, with a size range of 73 μm–4,680 μm and blue was the most common color recorded (46%). The frequency of occurrence of MP was higher in T. trachurus (70%) and lowest in M. sanguinea (17%). MP abundance ranged from 0.30 ± 0.63 MP. ind−1 in S. plana, to 2.46 ± 4.12 MP. ind−1 in S. colias. No significant correlation was found between the individual biometric parameters and total MP, fibers and fragments ingested by each species. The FTIR analysis revealed that polyester and polyethylene were the most common polymers present. These results can be used as a reference for future studies regarding the use of indicator species for monitoring MP pollution in the coast of Portugal.

This study aims to investigate a new method of glazing for improving the storage quality of frozen horse mackerel. Specifically, this study explored the effect of double-glazing with theaflavins on the quality of horse mackerel stored at −20°C for 28 weeks by comparing with unglazed and those single glazed with theaflavins. Chemical indicators were used to assess deterioration during storage, the water-holding capacity (WHC), weight loss, drip loss, and low-field nuclear magnetic resonance (LF-NMR) were used to analyze the water retention of fish and water migration in tissues. The water retention analysis results showed that double-glazing can maintain higher WHC, T22 values and lower weight loss, drip loss, T23 values at the end of storage. Chemical analysis results showed that double-glazing combined with theaflavins was highly effective in maintaining lower TVB-N, FAAs, MDA values, and higher SH, IFI values in frozen horse mackerel, especially theaflavins as inner layer glazed material, perhaps due to the synergistic effect of anti-crushing and antioxidant abilities. Therefore, the double-glazing with TF inner layer was more effective in controlling quality changes of frozen horse mackerel. [ABSTRACT FROM AUTHOR]

The gill tissue is the main site of metabolic enzymes or compensation, with the kidney tissue playing a supporting role. At the gill tissue, carbonic anhydrase enzymes (CAs) catalyze the hydration of CO2 to HCO3− and H+ for production to the H2O. In this work, the CA enzyme was purified from horse mackerel (Trachurus trachurus) gill with a specific activity of 21,381.42 EU/mg, purification fold of 150.61, total activity of 2347.68 EU/mL, and a yield of 16.13% using sepharose 4B-L-tyrosine-sulfanilamide affinity gel chromatography. For recording the enzyme purity, gel electrophoresis was performed, and single band was seen. The molecular weight of this enzyme was found approximately 35 kDa. Also, the inhibitory effects of different pesticides such as thiram, clofentezine, propineb, deltamethrin, azoxystrobin, and thiophanate and heavy metal ions such as Fe2+, Cu2+, Co2+, Pb2+ Hg2+, and As3+ on horse mackerel gill tissue CA enzyme activities were investigated. Our results indicated that these pesticides and metal ions showed inhibitory effects at low nanomolar and millimolar concentrations for fish gill CA enzymes, respectively. [ABSTRACT FROM AUTHOR]

This study estimated the growth of horse mackerel, Trachurus mediterraneus (Steindachner), populations from the western parts of the Black, Marmara, and Aegean seas. Dependencies of individual daily weight gain at age were determined. The calculations showed that in the area studied the highest absolute weight gain was 45.4 mg day−1 for fish at the age of 2.46 years from Zonguldak (Black Sea). The relative annual increase in the population biomass of T. mediterraneus inhabiting different areas of the Black, Marmara and Aegean seas was determined. It was revealed that the annual relative increase in the biomass of horse mackerel caught in the Black Sea exceeded that in the Marmara and Aegean seas. At the same time, the highest relative annual biomass increase (94.8%) was observed in populations from the Varna-Bourgas region and in the coastal waters of Sevastopol (70.9%) in the Black Sea. [ABSTRACT FROM AUTHOR]

Background. Atlantic horse mackerel, Trachurus trachurus (Linnaeus, 1758), is among bento-pelagic species subject to discard within deep-water rose shrimp fisheries, and how such species would react to light wavelength is therefore important, to be consistent with the Common Fishery Policy (CFP). Despite the existing literature currently available, there is still paucity of relevant information about how artificial light wavelengths affects the behaviour of T. trachurus juveniles. In this context, the effects of different artificial light wavelengths on some behavioural features of juvenile T. trachurus were investigated. Materials and methods. Maintained in a fish tank, the juveniles of Atlantic horse mackerel, after acclimatization, were subject to six different light wavelengths, representing the following colours: white, violet, blue, green, yellow, and red. Subsequently, behavioural features, specifically phototaxis (degree of attraction or repulsion toward the light source) were tested. Results. By phototaxis per light wavelength, the studied juvenile individuals produced statistical differences in the presence frequency (P < 0.05) revealed by blue that noticeably attracted some, relative to the white light that repulsed others. Yet, violet and red lights produced much less but no significant attraction of these juveniles (P > 0.05). Conclusion. The presently reported study has provided additional information about ecological knowledge and understanding specific to juvenile T. trachurus individuals, which can further the development of (selective) light fishing techniques, aimed at reducing unwanted catches of commercial pelagic fisheries. [ABSTRACT FROM AUTHOR]

In the South Eastern Black Sea, anchovy (Engraulis encrasicolus), sprat (Sprattus sprattus), and horse mackerel (Trachurus mediterraneus) are the most important small pelagic fish both ecologically and economically. The stomach contents of 1485 fish, including anchovy, sprat, and horse mackerel, were examined. Fish fed on 35 prey taxa, and there were dietary differences among predators. Anchovies predominantly consumed calanoid copepods and bivalves; sprats had a diet dominated by calanoid copepods and Chaetognatha (Parasagitta setosa); horse mackerel consumed mainly decapods and calanoid copepods. Copepods in the stomachs of sprat were more abundant and more frequent than in the stomachs of anchovy or horse mackerel during all year. As the anchovies and horse mackerel grew, their copepod consumption increased, but despite their size, sprats consumed a similar amount of copepods. Seasonal shifts in diet were observed in all three species. In winter and autumn months, all small pelagic fish consumed copepod species. The bivalve larvae were mostly consumed in summer by anchovies (N%: 72.98) and in spring by sprats and horse mackerel (N%: 88.59 and 81.08, respectively). Decapod species were preferred in spring months by horse mackerel. P. setosa was mostly consumed in autumn and winter by sprat. Anchovy showed a low dietary overlap with sprat but had a high dietary overlap with horse mackerel. The feeding strategy of anchovy seems to be mixed, while horse mackerel is a generalist at the individual level, and sprat is a specialist at the population level. [ABSTRACT FROM AUTHOR]

In this study, the effects of seasonal and sexual differences on the nutritional composition, macro (Na, Mg, P, K, Ca), trace element (Mn, Fe, Co, Cu, Zn, Mo, Ni, Se) and potential toxic metal levels (Cd, Pb, As) of horse mackerel (Trachurus trachurus) caught in the middle Black Sea coast during all seasons were investigated. The metal levels of muscle tissues of the examined specimens were determined using ICP-MS instrument. The results showed that horse mackerel had a high nutritional value in terms of protein and lipid levels. Metal levels were found to be different in terms of sexual and seasonal factors. With regard to macro element levels, horse mackerel muscle was found to be rich. Zn and Cu levels of the trace elements were below the legal limits specified by the codex. It was also observed that the levels of Cd and Pb in horse mackerel muscle tissue were below the FAO (Food Agriculture Organ U N 464:5–10, 1983) limit values and above the TFC (Turkish Food Codex 2011) limit values. In terms of EWI and EDI values, horse mackerel was found to be non-toxic. This study suggests that horse mackerel is beneficial seafood for human health and nutrition. [ABSTRACT FROM AUTHOR]

In this study, the concentrations of lead, cadmium and manganese were determined in horse mackerel (Trachurus mediterraneus) and whiting (Merlangius merlangus euxinus) that were caught in the Sea of Marmara. These are commonly consumed fish species in this region. Fish were provided by a fishermen quarterly between March 2013 and December 2013 and, separated according to size (small, medium and large). Pb(II), Cd(II) and Mn(II) levels were determined using the wet digestion method by Graphite furnace atomic atomic absorption spectrophotometer. According to this study, for horse mackerel, the highest concentration of lead, cadmium, and manganese was 6.69 µg kg−1 (September), 5.24 µg kg−1 (March) and 9.24 µg kg−1 (June), respectively. For whiting, the highest concentration of lead, cadmium, and manganese was 2.25 µg kg−1 (June), 0.263 µg kg−1 (September) and 10.4 µg kg−1 (June), respectively. These heavy metal levels in fish were found to be acceptable for human consumption according to World Health Organization border values. [ABSTRACT FROM AUTHOR]

Bu çalışma istavrit balığının Trachurus mediterraneus Steindachner, 1868 Doğu Karadeniz’de kafeslerde kültür potansiyeli üzerine yapılan ilk çalışmadır. Balıklar, ağ tuzaklarla doğadan yakalanmış ve doğrudan kafeslere transfer edilmiştir. Büyütme çalışması Ekim 2010 ile Ekim 2011 arasında yürütülmüştür. Ebatları 5x5x3 m olan kare kafes, birbirinden tamamen bağımsız eşit hacimli üç eşit küçük kafese 5x1,6x1.5 m bölünmüş ve her bir küçük kafese yaklaşık 1000’er adet balık stoklanmıştır. Balıklar ticari deniz levreği yemi ile doyuncaya kadar elle günde iki kez yemlenmiştir. Çalışmanın başında 12.20±0.97 cm ve 24.09±3.25 g olan ortalama boy ve ağırlık değerleri çalışma sonunda 19.61±1.47 cm ve 76.80±16.24 g’a n= 100 ulaşmıştır. Ortalama yem değerlendirme ve yaşama oranları sırasıyla 2.33±0.21 2.122.54 ve % 95.58-98.59 olarak hesaplanmıştır. Bu sonuçlara göre, deniz kafeslerinde istavrit balığının su sıcaklığının 12 °C’nin altına düştüğü kış ayları haricinde büyüyebildiği sonucuna varılmıştır

An endogenous protease in fish muscle, cathepsin B, was partially purified and characterized from horse mackerel meat. On SDS-PAGE of the purified enzyme under reducing conditions, main protein bands were detected at 28 and 6 kDa and their respective N-terminal sequences showed high homology to heavy and light chains of cathepsin B from other species. This suggested that horse mackerel cathepsin B formed two-chain forms, similar to mammalian cathepsin Bs. Optimum pH and temperature of the enzyme were 5.0 and 50 °C, respectively. A partial cDNA encoding the amino acid sequence of 215 residues for horse mackerel cathepsin B was obtained by RT-PCR and cloned. The deduced amino acid sequence contains a part of light and heavy chains of cathepsin B. The active sites and an N-glycosylation site were conserved across species. We also confirmed that the modori phenomenon was avoided by CA-074, a specific inhibitor for cathepsin B. Therefore, our results suggest that natural cysteine protease inhibitor(s), such as oryzacystatin derived from rice, can apply to thermal-gel processing of horse mackerel to avoid the modori phenomenon. Meanwhile, this endogenous protease may be used for food processing, such as weaning meal and food for the elderly.

The Mediterranean horse mackerel Trachurus mediterraneus, (Steindachner, 1868) is one of the most exploited commercial species of the fisheries in the Black Sea basin. Their economic importance and the need of adequate measures for conservation and management of this resource, require more information about their population dynamics. This paper presents results on temporal variations of total length and weight, age composition, growth parameters and sex ratio of the Mediterranean horse mackerel populations, on the Romanian Black Sea coast. Their mean total length was higher in 2018 than in 2017. One and two year old individuals dominated during the period 2017 to 2018. Females dominated in both 2017 (63%) and 2018 (57%). [ABSTRACT FROM AUTHOR]

Abstract: It is known that the formation of ice crystals has a negative impact on the flesh quality of frozen meat. This study focuses on how the formation of ice crystals in the dorsal ordinary muscle affects the flesh quality of frozen horse mackerel (Trachurus japonicus). Freeze‐thawed muscle specimens (F‐TMS) of horse mackerel were first stored at −24C and then thawed. The K‐value, expressible water, breaking strength of unfrozen muscle specimens (UMS) and F‐TMS, and histological structure (light microscope [LM], scanning electron microscope [SEM] of UMS, frozen muscle specimens [FMS], and F‐TMS) were investigated. K‐values were higher in the F‐TMS than in the UMS, and the increasing rate of K‐value in F‐TMS was approximately 1.4‐fold higher than UMS. Similarly, the percentage of expressible water was higher in the F‐TMS than in the UMS. The breaking strength of the UMS decreased with storage period, but it remained at a higher level than that of F‐TMS. Numerous ice crystal formations in muscle cells of FMS and small interstices between cells of F‐TMS were observed under LM. Moreover, we observed a relatively collapsed honeycomb structure of the extracellular matrix (ECM) under SEM, and found that collagen fibril networks of endomysiums became looser after thawing. Therefore, ice crystals contribute to vulnerabilities in the ECM. These results suggest that a decrease of freshness and the degradation of physical properties caused by ECM destruction may be due to the formation of ice crystals in muscle structures during freezing, leading to the deterioration of flesh quality during storage. Practical applications: The flesh quality deteriorated after thawing on the basis of degradation of physical properties. Moreover, it could be presumed that the K‐value increase was exacerbated by ice crystals, and the decreasing speed of chemical freshness was sped up accompanied by ice storage after thawing. Thus, the formation of ice crystals, which destroyed the muscle cells and structures, may be one of the dominant factors causing the deterioration in the flesh quality. [ABSTRACT FROM AUTHOR]

Gear selectivity and discards are important issues related to fisheries management but separately modelled. This work examines for the first time the overall size-selection pattern on the total amount of individuals of a species entering the trawl codend. An innovative approach was used based on modelling the escapement through the codend in the sea and the subsequently selection process by the fisher on the deck of the fishing vessel resulting into the discards and landings. Three different trawl codends and three species were investigated in the case study conducted. A dual sequential model accounting for both gear size-selectivity and the subsequent fisher-size-selectivity was applied, under the hypothesis that a fish entering the codend can follow a multinomial distribution with three probabilities, the escape, the discard and the landing probability, respectively. The model described the escape probability through the gear and the landing probability by the fisher as S-shaped curves leading to a bell-shaped curve for the discard probability affected by both gear and fisher selection. The model described well the experimental data in all cases. Sampling scheme of three compartments proved adequate. The model provides at the same time selectivity and discards parameters useful in fisheries management. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The taxonomic status of the horse mackerel, Trachurus mediterraneus ponticus (Aleev, 1956), which inhabits the Black Sea, has been clarified based on the analysis of variation in the nucleotide sequence of the mtDNA cytochrome b (Cyt-b) locus. A comparison of this species with the horse mackerel from the Mediterranean basin and the World Ocean has shown that the Black Sea horse mackerel is neither an independent species nor a subspecies and can only be qualified as the species Trachurus mediterraneus (Steindachner, 1868) distributed throughout the Mediterranean Sea basin. A hypothesis has been made about the possible cause of the origin and existence of two forms, “large” and “small”, of the horse mackerel. By using the technique of calculating ontogenetic trajectories, it has been found that these are two morpho-ecological forms, whose differentiation is most likely determined by the type of feeding. [ABSTRACT FROM AUTHOR]

Port landing specimens of torpedo scad, Megalaspis cordyla were collected at monthly intervals from August 2013 to June 2014 from the northern Arabian Sea coast of Pakistan. The life history characteristics revealed that torpedo scad has a prolonged breeding season which occurred with two peaks: from May to June and from November to February. The spawning seasonality was also validated with microscopic gonad examination.The highest GSI value was noted in May and January whereas the lowest in November was recorded for both sexes. The age at which individuals of both sexes become 50% mature (t50) was estimated as 2.44 year. Life span (tmax) calculated as 3.96 years for male and females. The size of 270 and 265 mm at which 50% individuals attained sexual maturity (L50) was determined for males and females respectively. The reproductive potential (fecundity)was made from ten ripe females ranged from 29-43.8 cm TL and weighing 220-540 g of IV-V developmental stage was enumerated as 32306-236677 eggs (CV = 2.135) with an average number of eggs 86544 counted per ripe female/season. This study contains fundamental data of an important fish species in the northern Arabian Sea coast of Pakistan. It provides vital information to the fisheries managers for implementation on sustainable use of the resource during spawning season. [ABSTRACT FROM AUTHOR]

The horse mackerels of the genusTrachurus(Pisces: Carangidae) are commercially important pelagic fish resources worldwide. There have been several studies of the parasites infecting fishes of this genus, the first one concerning the occurrence of the coccidianGoussia cruciataThélohan, 1892. Horse mackerels have been targeted in recent projects, in a number of countries that exploit this fish resource (Argentina, Chile, European and Mediterranean countries, North America), with a view of using parasites to define population structure, in conjunction with other methods and techniques, to achieve a better understanding of fish stocks and to minimize risks of localized extinctions. However, information on the occurrence of parasites in this fish genus is scattered through a substantial number of scientific journals, some of them of difficult access. The present review aims to compile the up-to-date knowledge on the occurrence of parasites of horse mackerels, from protozoans to metazoans, their distribution in diverse geographical areas, and to review and provide references to the studies of parasites as indicators of population structure. [ABSTRACT FROM PUBLISHER]

Horse mackerel (Trachurus trachurus, Linnaeus 1758) fillets were inoculated with bacteriocin-like metabolite producer (Group A) and non-producer (Group B) strains of Pediococcus spp. (7 log CFU g-1), then samples were vacuum packaged and stored (4°C 10 days-1). pH values did not display differences between the groups (P>0.05). TVB-N and TMA-N values, total mesophilic and psychrophilic aerobic bacteria counts of all groups (Control, A and B) increased rapidly (TVB-N: 30.15, 33.86, 34.65 mg 100g-1; TMA-N: 11.63, 13.07, 13.20 mg 100g-1; mesophilic aerobic bacteria: 6.02, 6.30, 5.94 log CFU g-1; psychrophilic aerobic bacteria: 6.30, 6.24, 6.09 log CFU g-1), and exceeded the limits at the 2nd day of storage. However, sensory scores of the inoculated samples were higher than that of the controls during the storage. Sensory qualities of group A and B samples were acceptable until the 6th day, while control samples spoiled at the 4th day. Therefore, it was concluded that sensory quality of treated samples were better, but Pediococcus strains used in this study were not proper for preserving horse mackerel fillets especially at low storage temperatures.

Anisakidosis is a fish-borne zoonosis caused by parasitic nematodes of the family Anisakidae, of which the species belonging to Anisakis simplex complex are the most representative. It is considered an emerging disease in Spain. The objective of this study is to analyse the presence of larvae in fish frequently consumed in Spanish supermarkets, inferring the risk of infection. In total 1,786 specimens of 9 different fish species, from two geographical origins (Atlantic and Mediterranean), acquired fresh and not eviscerated were examined for anisakid nematodes. Analysis showed that 33.7% of the samples were parasitized by Anisakis larvae. The horse mackerel (Trachurus trachurus) presented the highest total prevalence (66.0%), followed by the silver hake (Merluccius bilinearis) (59.5%), the mackerel (Scomber scombrus) (58.4%), the blue whiting (Micromesistius poutassou) (53.9%) and the European hake (Merlucius merlucius) (45.0%). In general, the prevalence was higher in Atlantic than in Mediterranean fish. In all the species analysed, a higher presence of the parasite was detected in the viscera than in the flesh, although in the most parasitized species a noteworthy prevalence and abundance was observed in the flesh. In conclusion, risk factors, like fish species and origin, should be considered by consumers, in addition of following the recommendations established by Commission Regulation (EU) No1276/2011 and the Spanish Royal Decree 1420/2006.

Mechanically separated meat (MSM) is the product obtained by removing meat from bones by pressure application. Whole fillets and fish burgers from minced muscle and from mechanical separation of Atlantic horse mackerel ( Trachurus trachurus ) were evaluated immediately after processing (T 0 ) and after 90 days of storage at − 20 °C for parameters related to quality loss. Firstly, mechanical separation inhibited water losses (2.67% against 4.57 and 5.57% in whole fillets and burgers from minced muscle, respectively), but the colour of MSM was duller and redder than the samples from other groups. Horse mackerel contained low fat (< 1 g/100 g muscle), and high PUFAω3 content (around 57 g/100 g total fatty acids), especially EPA and DHA (around 52 g/100 g) regardless the treatment. However, the species was susceptible to oxidation, as revealed by the high TBARS content at T 0 (> 8 mg MDA-eq/100 g muscle). Nevertheless, Atlantic horse mackerel showed a high antioxidant capacity (ABTS, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid, DPPH, 2,2-diphenyl-1-picrylhydrazyl, and FRAP, ferric-reducing ability) at T 0 which may protect muscle against oxidative damages both during processing treatment and storage. Industrial relevance The mechanical separation process described in the article has been largely utilized for terrestrial animal products. However, it is seldom adopted by fish industry, especially for recovering discard fish species. Horse mackerel is an underutilized species, normally transformed into animal feed despite its high levels of omega-3 polyunsaturated fatty acids. Therefore this study was conducted in order to determine the effect of a mechanical separation technique on the physicochemical properties of horse mackerel. Our study showed that, although this species is susceptible to oxidative changes, mechanically separate meat can be a high-quality ingredient in burgers, nuggets, sticks, or even sauces which may represent a way for the valorisation of discard species. [ABSTRACT FROM AUTHOR]

Following the classic lines of evidence of Hunter et al. (Hunter, J. R., Macewicz, B., Lo, N. C. H., and Kimbrell, A. 1992. Fecundity, spawning, and maturity of female Dover sole Microstomus pacificus, with an evaluation of assumptions and precision. Fishery Bulletin US, 90: 101-128.) on the fecundity type of fishes (determinate vs. indeterminate), the stock of horse mackerel (Trachurus trachurus) in Atlantic Iberian waters (ICES Division IXa) was shown to exhibit a mixed picture. Total fecundity, the total number of secondary growth (SG) oocytes dropped during the spawning season and there were reproductively active individuals with a distinct size hiatus between primary growth (PG) oocytes and SG oocytes, while no massive atresia was observed in late-season spawners. All of these characteristics matched with evidence for determinate fecundity. However, daily decrease rate of total fecundity was lower than daily specific fecundity (i.e. the number of eggs produced daily per unit weight) by orders of magnitude which suggested that the stock of SG oocytes was replenished during the spawning period through de novo oocyte recruitment. In addition, the maximum number of batches in reproductively active females was lower than the predicted annual number of spawnings, while total fecundity in recent spawners--those containing post-ovulatory follicles--was not lower than the fecundity of the remaining reproductively active females. All of these results suggest that, despite the aforementioned mixed lines of evidence, the fecundity of horse mackerel is clearly indeterminate. We attribute these mixed characteristics to the fact that, unlike most typical indeterminate spawners, horse mackerel ceases to recruit new SG oocytes during the latter part of its spawning season. [ABSTRACT FROM AUTHOR]

The article presents study to compare proximate composition and fatty acid profile of on-growing and wild horse mackerels to evaluate the effect on their nutritional value, and reveals seasonal variations in the proximate contents and fatty acid profile of both on-growing and wild fish groups.