Search Results (51)

Novel therapeutic approaches for wound healing have included biomaterials from the Atlantic cod (Gadus morhua L.), with promising results in wound management. The use of extracellular vesicles (EVs), which can be isolated from cod biofluids, remains to be studied. EVs play key roles in cellular communication, and their use both as biomarkers and as therapeutic agents is widely reported in human pathologies, particularly with respect to mesenchymal stem cells. This pilot study characterized the total proteomic cargo content of EVs from cod serum and mucus and assessed the EVs’ potential for regenerative activity in wound-healing processes, using human and mouse fibroblast and keratinocyte in vitro scratch injury models. The pro-regenerative potential of both cod serum EVs and mucus EVs was identified, with differing capacities for accelerating wound closure in fibroblast and keratinocyte cells. This was further supported by varying effects of the cod serum EVs and mucus EVs on cellular vimentin and FGF-2 levels. The serum EV and mucus EV protein cargoes differed with respect to abundance of protein hits and associated enriched functional GO and KEGG pathways, but both were associated with immune, stress and wound-healing processes. Cod EVs may present as innovative therapeutic options for regenerative medicine applications, and our reported findings provide valuable insights for future in-depth studies. Full article

This study investigates the effects of warming water on growth in seven demersal fish species including Atlantic cod (Gadus morhua), American plaice (Hippoglossoides platessoides), Greenland halibut (Reinhardtius hippoglossoides), roughhead grenadier (Macrourus berglax) and three species of redfish (Sebastes spp.) in the Northwest Atlantic and compares the changes in growth across species. Length-at-age data were collected from EU bottom trawl surveys from 1993 to 2018, and bottom temperature data were obtained from the Copernicus Marine Service. Generalised additive mixed models (GAMMs) were used to describe the temperature effects on growth. The analysis was carried out separately for males and females. Both sexes of all species except American plaice showed significant temperature effects on growth. To obtain the growth parameters, von Bertalanffy growth functions (VBGFs) were fitted to the predictions from best-fit GAMMs for all species and both sexes under five different bottom temperature scenarios (3, 3.5, 4, 4.5 and 5 °C). The predictions from all best-fit GAMMs were broadly similar in form to the fitted von Bertalanffy growth functions (R² > 90%). Increased bottom temperature generally resulted in a decrease in the asymptotic length (L_∞) and an increase in the growth rate (k). The species with the most dramatic increase in k over the temperature range of 3 °C to 5 °C was Atlantic cod, for which k increased from 0.05 to 0.13 year⁻¹ in females and from 0.08 to 0.14 year⁻¹ in males. The maximum length (L_max), predicted by the VBGF at maximum age generally declined from 3 °C to 5 °C. The species with the most pronounced decline in L_max was beaked redfish (S. mentella). An increase in the proportion of smaller individuals could impact population productivity and result in lower biomass available to fisheries. Uneven changes in fish growth in the warming ocean could also have wider ecological implications and alter the trophic landscape. Full article

The visual underwater monitoring of fish size, position, and swimming speed is experiencing increasing interest in aquaculture and marine research. Despite the long-standing use of video monitoring, there is no methodological consensus, but numerous researchers and developers advocate for 3D video capture techniques to facilitate biometric estimations. Most of the previous systems, however, use partially synchronized cameras (within one frame), which causes an inherent error if observing moving fish in relation to the camera. This study proposes the use of a completely synchronized 3D camera system for underwater video capture, which can be calibrated, and which allows analyses to be performed using open-source software(s). We present data on the maximum theoretical error in the size estimation of swimming fish. This article presents a guide on how to build and set up the camera hardware and run the system, including a formal study investigating pre-measured lengths, and an informal study investigating the lengths of Atlantic cod (Gadus morhua). Full article

Acellular tissue matrices of fish skin origin are highly promising materials for tissue engineering due to their low biological risks and few religious restrictions. The main component of acellular fish skin matrices (AFSMs) is collagen, but collagen properties significantly differ between marine and freshwater fish. Although the characteristics of acellular matrices may vary, relevant reports about them are few. In this study, we used cod and tilapia fish skin as raw materials to prepare acellular matrices with low DNA content (≤50 ng/mg) and low endotoxin. They were denoted as C-AFSM (cod) and T-AFSM (tilapia) and had endotoxin removal rates of 92.47% and 96.73%, respectively. Their physicochemical properties, cytotoxicity, and wound healing effects were evaluated and compared. Scanning electron microscopy images showed that C-AFSM and T-AFSM had collagenous meshwork and high porosity. They also did not induce skin irritations. Their proliferation rates on mouse fibroblasts at 36 h were 192.21% ± 33.25% and 162.89% ± 36.47%, respectively. The wound healing effect of C-AFSM was faster than that of T-AFSM group (7 and 14 days: 45.3% ± 5.99% and 93.77% ± 1.58% for C-AFSM and 39.7% ± 2.84% and 93.35% ± 1.1% for T-AFSM, respectively). Therefore, the two acellular fish skin matrices can be used as tissue-engineering materials for wound repair, with C-AFSM being more effective than T-AFSM. Full article

Managing fishery resources is crucial to ensure the marine environment continues to provide diverse goods and services. To overcome difficulties of classical methods used for fish stock management, molecular tools have shown potential to address this issue assessing both targeted and non-targeted species. This study aims to evaluate the spatiotemporal diversity of fish using 12S rRNA gene eDNA metabarcoding sequencing in the Berlengas archipelago and compare two seawater eDNA sampling sources: samples collected by fishermen during their activities and those collected by our research team. The results indicated that autumn presented the highest diversity and that the area around Berlenga Island was the richest area, increasing biodiversity across the region. Fisher-collected samples were generally less diverse than those by the research team but detected species typical of deeper and open-ocean habitats, validating this sampling method. Our study also highlighted eDNA’s role in monitoring fish species by detecting unexpected species for the region, such as Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua), while cautioning against false positives like orange clownfish (Amphiprion percula) and blue tilapia (Oreochromis aureus). Future optimisation of our eDNA sampling methodology could better refine marine ecosystem dynamics around the UNESCO Biosphere Reserve of the Berlengas Archipelago, Portugal. Full article

Animals form functional units with their microbial communities, termed metaorganisms. Despite extensive research on some model animals, microbial diversity in many species remains unexplored. Here, we describe the taxonomic profile of the microbes from the outer gut mucus layer from the Northeast Arctic cod using a shotgun DNA sequencing approach. We focused on the mucus to determine if its microbial composition differs from that of the fecal microbiota, which could reveal unique microbial interactions and functions. Metagenomes from six individuals were analyzed, revealing three different taxonomic profiles: Type I is dominated in numbers by Pseudomonadaceae (44%) and Xanthomonadaceae (13%), Type II by Vibrionaceae (65%), and Type III by Enterobacteriaceae (76%). This stands in sharp contrast to the bacterial diversity of the transient gut content (i.e., feces). Additionally, binning of assembled reads followed by phylogenomic analyses place a high-completeness bin of Type I within the Pseudomonas fluorescens group, Type II within the Photobacterium phosphoreum clade, and Type III within the Escherichia/Shigella group. In conclusion, we describe the adherent bacterial diversity in the Northeast Arctic cod’s intestine using shotgun sequencing, revealing different taxonomic profiles compared to the more homogenous transient microbiota. This suggests that the intestine contains two separate and distinct microbial populations. Full article

Coastal aquaculture and local fisheries interact in shared marine environments, influencing each other synergistically and/or antagonistically. Salmon farming, notably with open-net sea cages along the Norwegian coast, attracts wild fish due to increased food availability from uneaten feed, but it also exposes wild fish to farm emissions like waste and toxic chemicals (de-lice treatments, antifouling and medical agents). The attraction behaviour of wild fish can impact fatty acid composition in fish tissues, influenced by the high terrestrial fat content in salmon aquafeed. We study how the Atlantic cod, aggregating around salmon farms in a subarctic fjord in Northern Norway, can be affected, potentially altering their natural diet and fatty acid profiles. Our study compares the muscle-tissue fatty acid compositions of cod caught near aquaculture facilities (impact) versus fish caught in neighbouring fjords (control), and we hypothesise decreased omega-3 fatty acids near farms. The analysis revealed no significant differences in the fatty acid concentrations or categories between the impacted and control fish, challenging our initial expectations. However, differences were found for C18:1(n9)t (elaidic acid), with a higher value in the impacted fish. These findings suggest that salmon farming’s influence on cod’s fatty acid profiles in the flesh (i.e., relevant for the nutritional quality of the fillets that consumers eat) may be limited or minimal despite their aggregative behaviours around farms. The threshold levels of salmon feed consumed by wild cod before it affects the quality and survival of, e.g., sperm or other life stages, are not known and require new investigations. This study underscores the complexity of interactions between aquaculture and wild fisheries, impacting both ecological dynamics and consumer perspectives on seafood quality and health benefits. Full article

The results of our preliminary studies indicated that the diets of predatory fishes can be bioindicators of faunistic changes in ecosystems and indirectly of changes taking place in aquatic environments in the Pomeranian Bay. We examined the diet composition of top predators Gadus morhua, Sander lucioperca, Perca fluviatilis, and the mesopredator Neogobius melanostomus. The diet composition of the perch, pikeperch, and round goby in the Pomeranian Bay was analyzed for the first time. Our findings indicated that perch, an euryphagous species, is the best potential bioindicator because it is present in the area studied most of the year and has a low to moderate feeding index (FI). Baltic cod, also an euryphagous species, could be a good bioindicator in the areas where it is abundant and occurs frequently, but not in the Pomeranian Bay, where it is caught mainly in the fall. Round goby, which is present in the area studied and had a low FI, is a stenophagous species that preys mainly on benthic species, while pikeperch had a very high FI and the least number of prey species in its diet. The results of trophic interaction analysis among the predators analyzed and their non-native/invasive prey are also provided. Full article

During the desalting of salted cod, significant textural, histological, and biochemical changes occur. Understanding these changes is crucial for enhancing the preservation and extending the shelf life of desalted cod. This study aimed to investigate the physicochemical quality parameters and enzymatic activities during the desalting process of cod (16 h at 4 and 20 °C) and to extend the shelf life of desalted cod through high-pressure processing (HPP) at 400 and 550 MPa for 5 min. During desalting, a correlation was noted between the pH and trimethylamine content in samples desalted at 20 °C, with both parameters increasing in the initial 4 h and stabilizing thereafter. The soluble protein in cod muscle decreased over desalting time, as it dissolved into the desalting water. Enzymatic activity showed a decline in cathepsins (B and D) and acid phosphatase throughout desalting, whereas lipase activity increased, particularly at 20 °C. HPP effectively extended the shelf life of desalted cod by controlling endogenous microbial growth, enabling an extension to 14–21 days compared to the 7 days observed in untreated control samples. This study highlights quality changes during desalting, with lesser effects at lower temperatures. Subsequent HPP improved the microbiological quality of desalted cod during refrigerated storage. Full article

There is a need to find novel sources of fertilizers to meet the increasing food demands of a growing human population and alternatives to mined and synthetic fertilizers for the certified organic sector. Composting is a common method for processing and stabilizing organic residues for use in horticulture. To that end, a small-scale composting experiment with six combinations of dried and ground rockweed (Ascophyllum nodosum), algae fiber from chemically processed rockweed, ground bones and fishmeal from cod (Gadus morhua), and ground blue mussels (Mytilus edulis) was conducted in Dewar flasks to assess whether these residues are suitable for composting and have potential for use as fertilizers. Expanded clay aggregates were used as a bulking material. Physicochemical analyses were performed on the residues and their mixtures before and after composting, and the temperature in the flasks was monitored for 92 days. Suitability was determined by evaluating the temperature dynamics, changes in physiochemical parameters, and nutrient profiles. All treatments generated heat, with reductions in C/N ratio, weight, and volume, demonstrating suitability for composting. The treatments with algae fiber had a higher mean temperature (34.5 vs. 29.0 °C) and more degree days above the thermophilic range (mean = 176- vs. 19-degree days), the greatest reduction in volume (mean = 35% vs. 27%), and the lowest C/N ratios at the end of active composting (18 vs. 24) compared to the treatments with dried and ground seaweed. In terms of fertilizer value, none of the finished composts were balanced for use as fertilizers alone and, in some cases, contained too much Na, but contained sufficient concentrations of K, S, Mg, and Ca and could be a valuable source of these nutrients and organic matter in combination with other N- and P-rich sources. Full article

In the marine environment, fish parasites are present in most seafood species. The most common are nematodes of the genus Anisakis, which can parasitize human tissues, causing anisakiasis and allergies—in some cases with a strong reaction, such as anaphylactic shock. This happens when people ingest live or dead larvae present in the muscles or viscera of a wide range of fish and cephalopods. Consumer education has been positioned as one of the most effective alternatives for its prevention. This study, carried out in Asturias (northwest Spain), sought to identify the seafood products that present the greatest risk of anisakiasis for consumers, taking into account their consumption, the prevalence of Anisakis, and consumer knowledge about this parasitosis. In the results, hake (Merluccius merluccius) and cod (Gadus morhua), frequently consumed in the region and with high parasite prevalence, do not pose a great risk because they are consumed when well cooked. Instead, sardine (Sardina pilchardus), highly consumed and less parasitized, and anchovy (Engraulis encrasicolus), highly parasitized and less consumed, would exhibit a medium risk. Young participants know more about the risks of anisakiasis from raw seafood. The gaps detected in the knowledge about the ability of temperature treatments to eliminate parasites, especially in allergic people, must be addressed for better prevention. We suggest campaigns adapted to the population sectors. Full article

Egg quality in fishes is commonly determined by fertilisation success and cleavage patterns as a phenotypic outcome of underlying regulatory mechanisms. Although these phenotypic estimators of egg quality are useful in farming conditions, these “good quality” egg batches do not always translate to good larval growth and survival. The identification of genes involved in embryonic development may help find links between genetic factors of maternal origin and egg quality. Herein, the relative expression of seven stage-specific developmental genes of Atlantic cod was analysed using quantitative PCR to understand the function during embryogenesis and its relationship with egg quality. Genes ccnb2 and pvalb1 showed significant differential expression between developmental stages and significant upregulation from blastula and somite stages, respectively. The comparison of spawning batches showed that the relative gene expression of genes ccnb2, acta, tnnt3 and pvalb1 was significantly higher from the middle of the spawning season where phenotypic quality estimators establish the best egg quality. Moreover, a positive significant correlation was observed between quality estimators based on egg morphology and the genetic expression of genes acta and acta1 during somitogenesis. This study suggests that the combination of quality estimators, genetics and batch timing could help optimise reproductive protocols for commercial stocks of Atlantic cod. Full article

Otoliths of the fish’s inner ear serve as a natural chronological recorder because of their continuous formation marked by daily, monthly, and annual increments. Despite their importance, the comprehensive protein content of otoliths remains not fully identified. Using the label-free shotgun proteomics method with one-dimensional liquid chromatography coupled to electrospray ionization-orbitrap tandem mass spectrometry, we quantified a broad range of proteins, with individual otoliths containing between 1341 and 1839 proteins. The identified proteins could potentially serve as a blueprint for fish growth from embryo to adult. We quantified eleven heat-shock proteins (HSPs) in both sexes and several proteins impacted by endocrine disruptors, indicating the otolith’s capacity to reflect environmental stress, potentially linked to climate change effects and altering of hormonal and neuroendocrine functions. Our bioinformatic ontology analysis confirmed the presence of proteins critical for various biological processes, including structural and enzymatic proteins. Protein–protein interaction (PPI) mapping also identified key interactions between the identified proteins. These findings significantly advance our understanding of otolith proteomics, offering a solid foundation for future work. Most of the identified proteins deposited daily and influenced by the environment were not implicated in the biomineralization of otolith, raising the potential for the otolith proteome to recreate details of fish life history at previously unrealized levels. Full article

The overall objective of the study presented in this paper was to evaluate the selectivity properties of three innovative codends in Baltic cod fishing: (1) an ultracross codend of 120 mm square mesh, (2) an ultracross codend with additional devices reducing the speed of water flow—one tarpaulin diffuser and one net confusor of 120 mm mesh, and (3) an ultracross codend with two tarpaulin diffusers and two net confusors of 120 mm mesh. These codends were firstly tested at sea by single trawls and compared to T90 and herring codend trawls, allowing assessment of caught fish mass and dimensions. Additionally, a special divided small-mesh coat for the innovative codends enabled determination of the amount as well as the length and mass of cod escaping from the codend both while the trawling gear was towed and while it was hauled. Further validation of codend selectivity was carried out by a double (twin) bottom trawl set deployed from one cutter in various variants of innovative codends compared to standard ones. The results of the study indicate that the use of an innovative ultracross codend and innovative devices reducing the water flow speed (tarpaulin diffusers and 120 mm net confusors) significantly reduces the number of undersized cod (<35 cm), even down to 1.3%, in the haul and contributes to a reduction in invisible mortal discard. Full article

In the context of global warming and the concurrent decrease in ectothermic fish body size, the mechanisms driving this phenomenon remain a subject of scientific debate. This study, utilizing the Atlantic cod (Gadus morhua) as a model organism, delves into the behavioral size-dependent temperature preference in the context of climate change. A significant negative correlation between temperature preference and fish size was discovered, aligning with in situ habitat temperatures and optimal physiological performance metrics from other studies. This correlation suggests that larger fish exhibit a behavioral preference for colder areas, potentially leading to shifts in distribution toward polar regions or deeper waters in response to local global warming. The findings contribute to predictions of species distribution shifts, emphasizing the critical role of size-dependent temperature preference in shaping fish populations and offering valuable insights for conservation efforts. Additionally, the study uncovers a noteworthy relationship between body size and thermal safety margins in fish behavior, providing a novel avenue for future research into the intricate dynamics of thermal regulation in response to climate change. Overall, this research enhances our understanding of the complex interplay between temperature, fish size, and ecological responses, offering crucial information for informed conservation and management strategies. Full article