The global trade in ornamental fish involves c. 125 countries worldwide and is worth c. US $15–30 billion each year. This total is dominated (90%) by freshwater fishes, most of which are sourced from ...breeding facilities located in developing countries, typically in Asia or South America, but also in Israel, USA and Europe. Some fish are still obtained from natural (wild) sources, but the exact percentage of wild‐caught fish is difficult to quantify given a lack of reliable data. Although c. 1000 species of freshwater fishes are widely available (from a total of > 5300 on sale), the most dominant freshwater fishes in the market comprise only 30 species from the orders Cyprinodontiformes, Perciformes, Characiformes and Siluriformes. In this perspectives review paper, illustrative example case studies of wild‐fish collecting (Barcelos and Rio Xingu, Brazil) and breeding projects (Java, Indonesia) are described. In addition, wild‐collecting expeditions to West Papua, Indonesia are discussed, focused on discovering novel species of rainbowfish (Melanotaeniidae) for breeding in captivity. Sustainability of the aquarium industry is considered in its broadest sense. The aquarium industry has been portrayed as both a major threat to natural ecosystems, but also as being part of the solution in terms of helping to maintain species when they have gone extinct in the wild or offering an income to impoverished citizens who might otherwise engage in much more destructive practices.
Fish oil has been broadly reported as a potential supplement to ameliorate the severity of some skin disorders such as photoaging, skin cancer, allergy, dermatitis, cutaneous wounds, and ...melanogenesis. There has been increasing interest in the relationship of fish oil with skin protection and homeostasis, especially with respect to the omega-3 polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). The other PUFAs, such as α-linolenic acid (ALA) and linoleic acid (LA), also show a beneficial effect on the skin. The major mechanisms of PUFAs for attenuating cutaneous inflammation are the competition with the inflammatory arachidonic acid and the inhibition of proinflammatory eicosanoid production. On the other hand, PUFAs in fish oil can be the regulators that affect the synthesis and activity of cytokines for promoting wound healing. A systemic review was conducted to demonstrate the association between fish oil supplementation and the benefits to the skin. The following describes the different cosmetic and therapeutic approaches using fatty acids derived from fish oil, especially ALA, LA, DHA, and EPA. This review summarizes the cutaneous application of fish oil and the related fatty acids in the cell-based, animal-based, and clinical models. The research data relating to fish oil treatment of skin disorders suggest a way forward for generating advances in cosmetic and dermatological uses.
The immunomodulatory effects of omega-3 and omega-6 fatty acids are a crucial subject of investigation for sustainable fish aquaculture, as fish oil is increasingly replaced by terrestrial vegetable ...oils in aquafeeds. Unlike previous research focusing on fish oil replacement with vegetable alternatives, our study explored how the omega-6 to omega-3 polyunsaturated fatty acid (PUFA) ratio in low-fish oil aquafeeds influences Atlantic salmon's antiviral and antibacterial immune responses. Atlantic salmon were fed aquafeeds rich in soy oil (high in omega-6) or linseed oil (high in omega-3) for 12 weeks and then challenged with bacterial (formalin-killed Aeromonas salmonicida) or viral-like (polyriboinosinic polyribocytidylic acid) antigens. The head kidneys of salmon fed high dietary omega-3 levels exhibited a more anti-inflammatory fatty acid profile and a restrained induction of pro-inflammatory and neutrophil-related genes during the immune challenges. The high-omega-3 diet also promoted a higher expression of genes associated with the interferon-mediated signaling pathway, potentially enhancing antiviral immunity. This research highlights the capacity of vegetable oils with different omega-6 to omega-3 PUFA ratios to modulate specific components of fish immune responses, offering insights for future research on the intricate lipid nutrition-immunity interplay and the development of novel sustainable low-fish oil clinical aquaculture feeds.
Abstract
Introductions of non‐native freshwater fish continue to increase globally, although only a small proportion of these introductions will result in an invasion. These invasive populations can ...cause ecological impacts in the receiving ecosystem through processes including increased competition and predation pressure, genetic introgression and the transmission of non‐native pathogens. Definitions of ecological impact emphasize that shifts in the strength of these processes are insufficient for characterizing impact alone and, instead, must be associated with a quantifiable decline of biological and/or genetic diversity and lead to a measurable loss of diversity or change in ecosystem functioning. Assessments of ecological impact should thus consider the multiple processes and effects that potentially occur from invasive fish populations where, for example, impacts of invasive common carp
Cyprinus carpio
populations are through a combination of bottom‐up and top‐down processes that, in entirety, cause shifts in lake stable states and decreased species richness and/or abundances in the biotic communities. Such far‐reaching ecological impacts also align to contemporary definitions of ecosystem collapse, given they involve substantial and persistent declines in biodiversity and ecosystem functions that cannot be recovered unaided. Thus, while not all introduced freshwater fishes will become invasive, those species that do develop invasive populations can cause substantial ecological impacts, where some of the impacts on biodiversity and ecosystem functioning might be sufficiently harmful to be considered as contributing to ecosystem collapse.
This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa, and ...Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture.
Vast global declines of freshwater and marine fish diversity and population abundance pose serious threats to both ecosystem sustainability and human livelihoods. Environmental DNA (eDNA)‐based ...biomonitoring provides robust, efficient, and cost‐effective assessment of species occurrences and population trends in diverse aquatic environments. Thus, it holds great potential for improving conventional surveillance frameworks to facilitate fish conservation and fisheries management. However, the many technical considerations and rapid developments underway in the eDNA arena can overwhelm researchers and practitioners new to the field. Here, we systematically analysed 416 fish eDNA studies to summarize research trends in terms of investigated targets, research aims, and study systems, and reviewed the applications, rationales, methodological considerations, and limitations of eDNA methods with an emphasis on fish and fisheries research. We highlighted how eDNA technology may advance our knowledge of fish behaviour, species distributions, population genetics, community structures, and ecological interactions. We also synthesized the current knowledge of several important methodological concerns, including the qualitative and quantitative power eDNA has to recover fish biodiversity and abundance, and the spatial and temporal representations of eDNA with respect to its sources. To facilitate ecological applications implementing fish eDNA techniques, recent literature was summarized to generate guidelines for effective sampling in lentic, lotic, and marine habitats. Finally, we identified current gaps and limitations, and pointed out newly emerging research avenues for fish eDNA. As methodological optimization and standardization improve, eDNA technology should revolutionize fish monitoring and promote biodiversity conservation and fisheries management that transcends geographic and temporal boundaries.
Thousands of Scottish wild fish were screened for pathogens by Marine Scotland Science. A systematic review of published and unpublished data on six key pathogens (Renibacterium salmoninarum, ...Aeromonas salmonicida, IPNV, ISAV, SAV and VHSV) found in Scottish wild and farmed fish was undertaken. Despite many reported cases in farmed fish, there was a limited number of positive samples from Scottish wild fish, however, there was evidence for interactions between wild and farmed fish. A slightly elevated IPNV prevalence was reported in wild marine fish caught close to Atlantic salmon, Salmo salar L., farms that had undergone clinical IPN. Salmonid alphavirus was isolated from wild marine fish caught near Atlantic salmon farms with a SAV infection history. Isolations of VHSV were made from cleaner wrasse (Labridae) used on Scottish Atlantic salmon farms and VHSV was detected in local wild marine fish. However, these pathogens have been detected in wild marine fish caught remotely from aquaculture sites. These data suggest that despite the large number of samples taken, there is limited evidence for clinical disease in wild fish due to these pathogens (although BKD and furunculosis historically occurred) and they are likely to have had a minimal impact on Scottish wild fish.
Global marine fish harvests have reached a plateau over the last decade, and efforts to increase aquaculture tend to face limitations in terms of water resources and contamination problems. Of the ...current fish harvest, at least 50% is discarded as waste. The current situation requires efforts to process, preserve, and utilize the fish capture to minimize waste. Chemical and microbiological contamination limit the utilization of harvested fish. There is a need to improve fish preservation to minimize spoilage and to process them into more appealing products. Instead of resorting to individual food-processing methods, the efficiency of processing could best be increased by a combination of conventional and modern processing methods or by combinations of modern processing methods. Fish waste is a rich source of oils containing essential fatty acids, polypeptides, and amino polysaccharides that could be utilized through the upscaling of current scientifically proven methods to new processing technologies. The separation of collagens, gelatins, bioactive peptides, edible fish oils, and chitosan form the primary stages in the utilization of fish waste. The products need purification to meet food quality and safety standards and to have desirable industrial characteristics. The diversity of information and products generated through new methods require advanced data handling and prediction systems, such as artificial intelligence, to address food safety and to derive the best out of fish processing and utilization.
Vertebrate vision is accomplished through light-sensitive photopigments consisting of an opsin protein bound to a chromophore. In dim light, vertebrates generally rely on a single rod opsin rhodopsin ...1 (RH1) for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their
gene repertoires. Among these, the silver spinyfin (
) stands out as having the highest number of visual opsins in vertebrates (two cone opsins and 38 rod opsins). Spinyfins express up to 14
s (including the most blueshifted rod photopigments known), which cover the range of the residual daylight as well as the bioluminescence spectrum present in the deep sea. Our findings present molecular and functional evidence for the recurrent evolution of multiple rod opsin-based vision in vertebrates.
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