Scomber Scombrus Research Articles

Nijerya Kwara eyaletinde seçilmiş iki soğuk oda işletmesinde Scomber scombrus ve Clupea harengus’taki aflatoksin, bakteri ve ağır metal birikimi

Impurities found in fish have been a major cause of disease and illness to consumers. This study's objective was to evaluate the total aflatoxin, heavy metal and microbial load in two frozen fish: Scomber scombrus and Clupea harengus from two (2) cold room facilities in Omu-Aran and Ilorin. Heavy metals, aflatoxin and microbial load were investigated using standard methods. Health risk was also determined using health risk index (HRI), daily intake of metals (DIM), and health quotient (HQ), and total toxicity of metals (TTM). Cd, Cu, Ni, Pb, Mn and Cr did not differ significantly (p>0.05) in both species from both locations. Nickel was lower than the recommended limit by World Health Organization (WHO). Level of Mn and Cr were higher in both species. Mn load was higher in the muscles of the sampled fish than in the gills from September through to November with highest value of 1.26±0.08 and 1.30±0.12 obtained for S. scombrus and C. harengus. Highest concentrations of all metals was observed in the gills except manganese and copper [Cd = 0.03 (S. scombrus), Cr = 1.22±0.13 (S. scombrus), Ni = 0.025±0.04 (S. scombrus), Pb = 0.06±0.02 (S. scombrus)]. HRI was > 1 in the different age groups for the different metals. TTM was > 1 in both species. Total aflatoxin level was higher in the gills (4.25 – 5) ppb than in the muscle (1.5 - 3) ppb for both locations respectively. Vibrio spp. and non-coliform bacteria were high in both species from both locations. The study concludes that heavy metal loads (Mn, Cd, Cu, Cr, and Ni) were more than the permitted limitations imposed by FAO, WHO and EU legislation for fish and fish products placing consumers at health risk.

DNA metabarcoding of cloacal swabs provides insight into diets of highly migratory sharks in the Mid-Atlantic Bight.

The abundances of migratory shark species observed throughout the Mid-Atlantic Bight (MAB) during productive summer months suggest that this region provides critical habitat and prey resources to these taxa. However, the principal prey assemblages sustaining migratory shark biomass in this region are poorly defined. We applied high-throughput DNA metabarcoding to shark feces derived from cloacal swabs across nine species of Carcharhinid and Lamnid sharks to (1) quantify the contribution of broad taxa (e.g., invertebrates, fishes) supporting shark biomass during seasonal residency in the MAB and (2) determine whether the species displayed distinct dietary preference indicative of resource partitioning. DNA metabarcoding resulted in high taxonomic (species-level) resolution of shark diets with actinopterygian and elasmobranch fishes as the dominant prey categories across the species. DNA metabarcoding identified several key prey groups consistent across shark taxa that are likely integral for sustaining their biomass in this region, including Atlantic menhaden (Brevoortia tyrannus), Atlantic mackerel (Scomber scombrus), and benthic elasmobranchs, including skates. Our results are consistent with previously published stomach content data for the shark species of similar size range in the Northwest Atlantic Ocean, supporting the efficacy of cloacal swab DNA metabarcoding as a minimally invasive diet reconstruction technique. The high reliance of several shark species on Atlantic menhaden could imply wasp-waist food-web conditions during the summer months, whereby high abundances of forage fishes sustain a diverse suite of migratory sharks within a complex, seasonal food web.

UV-photochemical vapor generation coupled to hydride generation AAS in the study of dietary intake of Se, Hg, Cd, and Pb from fish

The consumption of fish by pregnant and lactating women is at the center of attention both from the point of view of ensuring healthy nutrition for fetal and neonatal development, and from the toxicological point of view. This research included a questionnaire survey on the frequency of fish consumption and the particular fish species consumed by 180 pregnant and lactating women in the Czech Republic, as well as the determination of Se, Hg, Cd, and Pb in the most commonly consumed species available on the Czech market. For this purpose, an analytical method for the determination of total selenium in biological samples using UV-photochemical vapor generation coupled to hydride generation atomic absorption spectrometry (UV-PVG-HG-AAS) was developed. This unique UV-photoreactor enables accurate and precise determination of Se with a detection limit of 0.007 mg/kg. Fish consumption by female respondents was generally low compared to the EU average. The determined Se contents in samples indicate a low intake of Se from fish in the Czech Republic; one third of the samples had Se contents below the detection limit. The highest Se contents were observed in the species Scomber scombrus, Sander lucioperca, and Thunnus albacares. The Hg content in fish samples did not exceed the EU maximum permissible values for mercury and methylmercury. The Tolerable Weekly Intake (TWI), which is 1.3 μg/kg of body weight per week, was not exceeded by any of the respondents. The maximum permissible value for Cd given by the European Commission was exceeded in the case of one sample of Scomber scombrus. Most of the samples had Cd content below the detection limit (0.002 mg/kg). The content of Pb in the analyzed samples was below the detection limit (0.013 mg/kg).

Deep‐sea sponge derived environmental DNA analysis reveals demersal fish biodiversity of a remote Arctic ecosystem

AbstractThe deep‐sea is vast, remote, and largely underexplored. However, methodological advances in environmental DNA (eDNA) surveys could aid in the exploration efforts, such as using sponges as natural eDNA filters for studying fish biodiversity. In this study, we analyzed the eDNA from 116 sponge tissue samples and compared these to 18 water eDNA samples and visual surveys obtained on an Arctic seamount. Across survey methods, we revealed approximately 30% of the species presumed to inhabit this area and 11 fish species were detected via sponge derived eDNA alone. These included commercially important fish such as the Greenland halibut and Atlantic mackerel. Fish eDNA detection was highly variable across sponge samples. Highest detection rates were found in sponges with low microbial activity such as those from the class Hexactinellida. The different survey methods also detected alternate fish communities, highlighted by only one species overlap between the visual surveys and the sponge eDNA samples. Therefore, we conclude that sponge eDNA can be a useful tool for surveying deep‐sea demersal fish communities and it synergises with visual surveys improving overall biodiversity assessments. Datasets such as this can form comprehensive baselines on fish biodiversity across seamounts, which in turn can inform marine management and conservation practices in the regions where such surveys are undertaken.

Proximate and Mineral Composition of Atlantic Mackerel (Scomber scombrus) and Atlantic Horse Mackerel (Trachurus trachurus)

Atlantic mackerel (Scomber scombrus) and Atlantic horse mackerel (Trachurus trachurus), locally known as kote, are fishery species consumed in Nigeria due to their high nutritional values. This research determined the nutritional composition of the local dried fish, Scomber scombrus and Trachurus trachurus. Results for Scomber scombrus shows the mean value of the moisture, ash, crude fat, crude fiber, and crude protein contents in percent (%) as: 5.260.00, 5.200.10, 35.600.00, 2.900.10 and 46.300.01 respectively. For Trachurus trachurus, the moisture, ash, crude fat, crude fiber, and crude protein contents in percent (%) were 9.520.00, 32.260.01, 24.140.00, 11.910.85 and 40.950.00 respectively. The mineral composition of Scomber scombrus was as follows: Sodium (Na) had the highest mineral composition with 78.90 mg/100g, followed by magnesium (Mg) with 15.90 mg/100g, manganese (Mn) with 0.86 mg/100g, zinc (Zn) with 0.282 mg/100g, and iron (Fe) with 0.10 mg/100g. Trachurus trachurus has magnesium (Mg) at 27.00 mg/100g as its highest mineral composition, followed by sodium (Na) at 22.50 mg/100g, zinc (Zn), iron (Fe) at 0.17 mg/100g, and manganese (Mn) at 0.09 mg/100g. It is concluded from the study, that Scomber scombrus and Trachurus trachurus are good sources of essential nitrates, fat, proteins containing essential amino acids, and other micronutrients that are beneficial to human health.

Classification of Fish Species Using Multispectral Data from a Low-Cost Camera and Machine Learning

This work creates a fish species identification tool combining a low-cost, custom-made multispectral camera called MultiCam and a trained classification algorithm for application in the fishing industry. The objective is to assess, non-destructively and using reflectance spectroscopy, the possibility of classifying the spectra of small fish neighborhoods instead of the whole fish for situations where fish are not completely visible, and use the classification to estimate the percentage of each fish species captured. To the best of the authors’ knowledge, this is the first work to study this possibility. The multispectral imaging device records images from 10 horse mackerel, 10 Atlantic mackerel, and 30 sardines, the three most abundant fish species in Portugal. This results in 48,741 spectra of 5 × 5 pixel regions for analysis. The recording occurs in twelve wavelength bands from 390 nm to 970 nm. The bands correspond to filters with the peculiarity of being highpass to keep the camera cost low. Using a Teflon tape white reference is also relevant to control the overall cost. The tested machine learning algorithms are k-nearest neighbors, multilayer perceptrons, and support vector machines. In general, the results are better than random guessing. The best classification comes from support vector machines, with a balanced accuracy of 63.8%. The use of Teflon does not seem to be detrimental to this result. It seems possible to obtain an equivalent accuracy with ten cameras instead of twelve.

Contribution of glass jar packaging to the environmental assessment of canned seafood products: Albacore tuna (Thunnus alalunga) and Atlantic chub mackerel (Scomber colias) as case studies

Canned seafood is a practical option for consumers with high nutritional value. However, packaging plays a key role in its environmental impacts due to the production of metal cans made by aluminium or tinplate and glass jars. The aim of this study was to perform a life cycle assessment of four seafood canned products in glass jars with Atlantic chub mackerel and albacore tuna. The contribution of end-of-life options for glass jar (reuse, recycle or landfill) was also evaluated, as well as environmental burden of storage at home scenarios of canned, chilled and frozen fish productspotential seafood waste in the different supply chains.Glass jar packaging contribution to environmental assessment of products was half compared with metal cans. The production of ingredients was the life cycle phase with highest contribution in all products followed by primary packaging for climate change impact category. Results pointed out the benefits of recycling glass jar with 8% GHG emissions reduction on average. Storage at the consumer stage represented less GHG emissions for canned products when compared to frozen when considering a period of more than one month.

Microbiome-based study in wild-caught Scomber scombrus fish products at the end of the supply chain

Fresh fish remain the dominant seafood forms and preservation technologies have enabled them to access ever more distant markets. In this study, we used metabarcoding of the 16S rRNA gene to generate gill microbiomes from Scomber scombrus bought at fishmonger's stores as fresh products but whose labels showed they had been harvested in the Atlantic or Mediterranean FAO fishing areas. Microbial data were analysed with the aim of evaluating their ability to maintain signals from their different geographical origins and the presence of taxa which can potentially act as spoilers, foodborne pathogens, or histamine producers. Results revealed that microbiota, at the end of the wild fish supply chain, had differences related to the two FAO fishing areas (Atlantic vs Mediterranean). Despite the presence of microbial genera potentially associated with spoilage, histamine-production or foodborne pathogens, their patterns confirmed that low-temperature storage is a traditional but effective method of preservation. However, the ongoing spoilage processes were more evident in fresh non-local specimens, dominated by psychrophilic Gram-negative bacteria, whereas fresh local specimens contained Planctomycetes taxa. Therefore, despite the current limitations mainly related to time and cost of the method, our study highlighted that microbiome-based applications are an emergent tool for food system transformation.

Environmental DNA reveals spatial patterns of fish and plankton diversity at a floating offshore wind farm

AbstractIn this study, we collected water eDNA from sampling stations at the first full scale floating offshore wind farm (OWF), the Hywind Pilot Park, east of Peterhead, UK, and a nearby reference area. We combined targeted droplet digital PCR (ddPCR) quantification of two commercially important species, Atlantic mackerel (Scombrus scombrus) and Atlantic herring (Clupea harengus), with metabarcoding of fish and plankton communities. The goal of this study was to assess the performance of eDNA data to characterize pelagic communities and its use for environmental monitoring. The metabarcoding recovered 26 fish species including both pelagic and demersal taxa. The plankton data were dominated by dinoflagellates (Karenia) and calanoid copepods. We found that both specific quantification of eDNA from mackerel and herring and eDNA metabarcoding of fish communities were able to reveal spatial patterns: Mackerel was most abundant in the surface across both OWF and reference sites; herring was present at a wider depth range. While ddPCR and metabarcoding data for these two species were broadly congruent, we observed detection/non‐detection mismatches for both methods, highlighting the need for robust sampling design. There was no consistent OWF versus reference area pattern in the demersal fraction of fish assemblages. We interpret our findings as representing a snapshot of fish school location around the time of sampling, and do not consider the single timepoint data from this pilot study to be sufficient to attribute any effects to the OWF itself. As a non‐invasive tool, we conclude that eDNA has a high potential in future environmental monitoring of OWFs. We recommend further ground‐truthing and biomass correlation of eDNA data with catch data and establishing eDNA time series as next steps towards implementation of eDNA in OWF environmental monitoring.

Evaluating the inhibition effect of a novel bio-packaging on histamine content in mackerel (Scomber scombrus): a new strategy with environment respect

This is the first study in which the impact of a new bio-packaging on histamine formation in mackerel was investigated. To monitor the preservation of fresh fish samples a treatment with innovative polymeric film and a soaking procedure in liquid new biomaterial was adopted. Ultra HPLC diode array detection (UHPLC-DAD) analyses for histamine monitoring were performed on fresh, packaged, and soaked mackerel samples at different time. The histamine content threshold value was up to 7 days, and after this period the results showed that histamine levels were affected by application of biomaterial. Significant increase was detected in sample that was not treated with biofilm. The new biofilm extended the shelf-life and reveals a promising packaging system to prevent histamine biosynthesis.

Epidemiology and antibiogram of listeria species from retail raw frozen atlantic mackerel fish (Scomber scombrus) in Nigeria

This study was undertaken to determine the epidemiology and antibiogram of Listeria species isolated from raw frozen Atlantic Mackerel (Scomber Scombrus) fish sold in Enugu State Southeastern Nigeria. Twentyfive grams each of raw fish gut and skin were collected from 800 raw fish sold in 8 major markets randomly selected from the study area. Isolation of Listeria was done using half and full fraser broths, and polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PALCAM) agar. Confirmation of the genus Listeria was done by a polymerase chain reaction. Identification of species was done using an analytic profile index (API) kit specific for Listeria. The antibiotic resistance of the isolates was determined using disc diffusion method. Out of the 800 fish samples, 38 (4.75%) were positive for Listeria species. Enugu North (6.50%) had significantly (P<0.05) higher prevalence than Enugu East (3.0%). Five Listeria species were identified. Listeria innocua (71.1%) predominated, followed by Listeria welshimeri (10.5%), Listeria ivanovii (7.9%), Listeria grayi (5.3%) and Listeria monocytogenes (5.3%). All the isolates were susceptible to the tested antibacterial agents. The occurrence of Listeria species in raw frozen Atlantic mackerel fish, poses a threat, when consumed raw or lightly cooked, to people especially the immunocomprormised persons whose population is increasing as a result of improvement in medical technology. Also, the possibility of cross contamination in the kitchen or food service establishments is also a concern. Since all the Listeria species got in this study showed 100% susceptibility to all the antimicrobials tested, therefore, there is no fear of acquiring and transferring antibiotic resistance genes from raw frozen Atlantic mackerel fish to the general human population.

Poleward spawning of Atlantic mackerel (Scomber scombrus) is facilitated by ocean warming but triggered by energetic constraints

Abstract The Northeast Atlantic mackerel is an income breeder with indeterminate fecundity, spawning in multiple batches at optimal temperatures around 11°C in the upper water column during February–July along the continental shelf from 36–62°N. Based on macroscopic staging of gonads (N ∼62000) collected in 2004–2021, we detected an on-going extension of spawning activities into the Norwegian Sea feeding area (62–75°N), reaching stable levels around 2012 onwards. This poleward expansion increased as more fish entered the area, whilst the maximum proportions of spawners concurrently dropped from about 75 to 15% from May to July. Detailed histological examinations in 2018 confirmed the macroscopic results but clarified that 38% of the spawning-capable females in July terminated their spawning by atresia. We suggest that increased access to suitable spawning areas (≥10°C), following ocean warming from 2002 onwards, functions as a proximate cause behind the noticed expansion, whereas the ultimate trigger was the historic drop in body growth and condition about 10 years later. Driven by these energetic constraints, mackerel likely spawn in the direction of high prey concentrations to rebuild body resources and secure the future rather than current reproduction success. The ambient temperature that far north is considered suboptimal for egg and larval survival.

Güllük Körfezi’nde (Ege Denizi) balık çiftlikleri etrafında yapılan kupes (Boops boops) uzatma ağı avcılığından elde edilen hedef-dışı av oranları

This study aims to reveal the by-catch rates for gillnet fishery, targeted Boops boops by small-scale fisheries around fish farms in Güllük Bay (Aegean Sea), and to determine the by-catch per unit effort (BPUE) rates. The study was carried out through deck sampling at Göltürkbükü, Gündoğan, Yalıkavak, and Torba fishing ports during two seasons between November and April (2017-2018 / 2018-2019). A total of 147 fishing operations from 13 boats were randomly monitored. In gillnet fishing for bogue, a total of 18163 kg of the catch was caught from 48 species belonging to 30 families, including invertebrates. The target Boops boops was the most common species with a rate of 91.9%, of which 8.1% was determined as a by-catch. The most caught by-catch species are Diplodus annularis (Linnaeus, 1758), Scomber colias (Gmelin, 1789), Trachurus trachurus (Linnaeus, 1758), Pagellus acarne (Risso, 1827), Scomber scombrus (Linnaeus, 1758). While the average BPUE was 4.77 ± 0.85 kg.1000 m-1 in 2018, it was 3.20 ± 0.58 kg.1000 m-1 in 2019. November gives the highest average in terms of BPUE values. The average BPUE ranged from 0 to 19.1 kg.1000 m-1 (mean: 7.97 ± 2.83 kg.1000 m-1). Statistically, there is a significant difference in BPUE values between the months (Kruskal-Wallis test, p < 0.05).

Enhancement of Lipid Stability of Frozen Fish by Octopus-Waste Glazing.

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.

Effect of Previous Frozen Storage and Coating Medium on the Essential Macroelement and Trace Element Content of Canned Mackerel.

The effect of previous frozen storage (-18 °C for 6 months) and different coating media (aqueous: water and brine; oily: sunflower, refined olive, and extra-virgin olive oils) on the essential macroelement and trace element content of canned Atlantic mackerel (Scomber scombrus) was studied. Previous frozen storage led to an increased (p < 0.05) content of canned samples of K (oil-coated samples) and Ca (all coating conditions) and to a decreased (p < 0.05) content of P (aqueous-coating samples) and S (water- and oil-coated samples). For trace elements, a content increase (p < 0.05) in Cu and Se (brine-canned samples) and Mn (water- and refined-olive-oil-coated samples) was detected in canned fish muscle with frozen storage. Concerning the coating effect, aqueous-coating samples showed lower (p < 0.05) Mg, P, S, K, and Ca contents than their corresponding oil-coated samples. For trace elements, lower average contents were found for Co, Cu, Mn, Se, and Fe in aqueous-coating fish muscle when compared to their counterparts coated in oily media. Content changes in the different elements in canned fish muscle are discussed based on interactions with other tissue constituents and modifications that such constituents undergo during processing (i.e., protein denaturation, liquor losses from the muscle, lipid changes).

Fish length, diet, and depth drive Anisakis levels in a zooplankton-feeding fish

Parasites play a key but overlooked role in the functioning of marine systems. Understanding the drivers of parasite infection in fish is thus crucial. Anisakis levels in the Atlantic horse mackerel Trachurus trachurus resulted from both biotic and environmental drivers. Ontogenic variation of the diet was the first driver of Anisakis level. The nonlinear pattern confirmed that the variation in parasitism was related to ontogenetic dietary shifts. The impact of depth on diet also explained the effect of depth on parasites. In deeper areas, fish only access pelagic prey, where Anisakis presence is high, consistent with the pelagic nature of the parasite. Finally, relative proportions of parasitic burden by tissue appeared to be driven by lipid content. In lipid-rich species like T. trachurus, Anisakis can find favorable conditions in the body cavity and in muscle and avoid the liver. Parasitism levels in fish are thus the result of patterns at play at different levels, and these factors should be better considered before being able to include parasites in an integrated vision of marine ecosystem functioning.

The genomic basis and environmental correlates of local adaptation in the Atlantic horse mackerel (Trachurus trachurus).

Understanding how populations adapt to their environment is increasingly important to prevent biodiversity loss due to overexploitation and climate change. Here we studied the population structure and genetic basis of local adaptation of Atlantic horse mackerel, a commercially and ecologically important marine fish that has one of the widest distributions in the eastern Atlantic. We analyzed whole-genome sequencing and environmental data of samples collected from the North Sea to North Africa and the western Mediterranean Sea. Our genomic approach indicated low population structure with a major split between the Mediterranean Sea and the Atlantic Ocean and between locations north and south of mid-Portugal. Populations from the North Sea are the most genetically distinct in the Atlantic. We discovered that most population structure patterns are driven by a few highly differentiated putatively adaptive loci. Seven loci discriminate the North Sea, two the Mediterranean Sea, and a large putative inversion (9.9 Mb) on chromosome 21 underlines the north-south divide and distinguishes North Africa. A genome-environment association analysis indicates that mean seawater temperature and temperature range, or factors correlated to them, are likely the main environmental drivers of local adaptation. Our genomic data broadly support the current stock divisions, but highlight areas of potential mixing, which require further investigation. Moreover, we demonstrate that as few as 17 highly informative SNPs can genetically discriminate the North Sea and North African samples from neighboring populations. Our study highlights the importance of both, life history and climate-related selective pressures in shaping population structure patterns in marine fish. It also supports that chromosomal rearrangements play a key role in local adaptation with gene flow. This study provides the basis for more accurate delineation of the horse mackerel stocks and paves the way for improving stock assessments.

Integrating machine learning with otolith isoscapes: Reconstructing connectivity of a marine fish over four decades.

Stable isotopes are an important tool to uncover animal migration. Geographic natal assignments often require categorizing the spatial domain through a nominal approach, which can introduce bias given the continuous nature of these tracers. Stable isotopes predicted over a spatial gradient (i.e., isoscapes) allow a probabilistic and continuous assignment of origin across space, although applications to marine organisms remain limited. We present a new framework that integrates nominal and continuous assignment approaches by (1) developing a machine-learning multi-model ensemble classifier using Bayesian model averaging (nominal); and (2) integrating nominal predictions with continuous isoscapes to estimate the probability of origin across the spatial domain (continuous). We applied this integrated framework to predict the geographic origin of the Northwest Atlantic mackerel (Scomber scombrus), a migratory pelagic fish comprised of northern and southern components that have distinct spawning sites off Canada (northern contingent) and the US (southern contingent), and seasonally overlap in the US fished regions. The nominal approach based on otolith carbon and oxygen stable isotopes (δ13C/δ18O) yielded high contingent classification accuracy (84.9%). Contingent assignment of unknown-origin samples revealed prevalent, yet highly varied contingent mixing levels (12.5-83.7%) within the US waters over four decades (1975-2019). Nominal predictions were integrated into mackerel-specific otolith oxygen isoscapes developed independently for Canadian and US waters. The combined approach identified geographic nursery hotspots in known spawning sites, but also detected geographic shifts over multi-decadal time scales. This framework can be applied to other marine species to understand migration and connectivity at a high spatial resolution, relevant to management of unit stocks in fisheries and other conservation assessments.

FoodSmarTag: An innovative dynamic labeling system based on pyranoflavylium-based colorimetric films for real-time monitoring of food freshness

A colorimetric pyranoflavylium-based pH-indicator with an improved formulation was obtained and studied as an intelligent label for food freshness monitoring. Pyranoflavylium pigment at 0.2% (w/w) and glycerol at 30% (w/w) were immobilized in a cellulose acetate matrix, and a thin film was obtained by the solvent casting method. The pH-responsive properties of the film were evaluated in solutions at different pH values (pH 4 to 8) and compared with a previous formulation. Film photostability and pigment migration over time were assessed. The label's performance was evaluated using real samples (fish and meat) at controlled conditions (3 °C and modified atmosphere packaging). The results showed that increased pigment concentration visually favored its colorimetric efficacy. Regarding pigment migration and photostability, the label showed to be suitable for application in fresh meat and fish packaging. The best performance was observed for the freshness monitoring of fish samples. The indicator demonstrated high efficacy in detecting spoilage of Atlantic horse mackerel (Trachurus trachurus). After 5 days of storage, freshness parameters exceeded the limit defined by EU regulations, indicating that the fish was unfit for consumption. Simultaneously, the yellow label started to turn purple, effectively indicating the beginning of the spoilage process.

Growth variability in Atlantic horse mackerel Trachurus trachurus (Linneus, 1758) across the central Mediterranean Sea: contrasting latitudinal gradient and different ecosystems

Data on Atlantic horse mackerel Trachurus trachurus (Linneus, 1758) were collected along 8-year acoustic surveys (2011-2018). Age and growth variability of horse mackerel from the Central Mediterranean Sea were investigated within different, contrasting habitats, from the south of Sicily to the north Tyrrhenian (Ligurian Sea). Data from satellite provided the habitat features along the study period over the whole surveyed area. For comparison purposes, according to the ecosystems difference the study area has been split into four subareas: Strait of Sicily (SoS), North of Sicily (NS), south Tyrrhenian Sea (ST) and north Tyrrhenian Sea (NT). In terms of the FAO Geographical Sub-Area definition the SoS corresponding to GSA15 and 16, NS to GSA 10 south, ST to GSA10 north and NT to GSA 9. Results showed a growth homogeneity in the study area, suggesting a unique stock inhabiting these waters. The only exception was recorded for juveniles (Age 0 class) in the SoS, where a lower size at age was detected compared to other areas. A multiple linear modelling analyses suggested that variability in length at age 0 was mainly linked to the oceanographic differences between an upwelling driven system (Strait of Sicily) and the other ecosystems, where enrichment processes are mainly due to river runoff (relevant in ST and NT). Namely, Absolute Dynamic Topography (ADT) and body condition factor (Kn) were significantly related to differences in length at age 0. Results revealed that currents (and gyres) are among the principal abiotic factors controlling Atlantic horse mackerel growth in its first year of life, suggesting that circulation and food-related processes (i.e., zooplankton concentration) are of major importance for this species. Finally preliminary observations suggest the Strait of Sicily may be the main spawning area among those analyzed.