Fishing Activities Research Articles

Distribution models of baleen whale species in the Irish Exclusive Economic Zone to inform management and conservation

Irish waters are under increasing pressure from anthropogenic sources including the development of offshore renewable energy, vessel traffic and fishing activity. Spatial planning requires robust datasets on species distribution and the identification of important habitats to inform the planning process. Despite limited survey effort, long-term citizen science data on whale presence are available and provide an opportunity to fill information gaps. Using presence-only data as well as a variety of environmental variables, we constructed seasonal ensemble species distribution models based on five different algorithms for minke whales, fin whales, humpback whales, sei whales, and blue whales. The models predicted that the coastal waters off the south and west of Ireland are particularly suitable for minke, fin and humpback whales. Offshore waters in the Porcupine Seabight area were identified as a relevant habitat for fin whales, sei whales and blue whales. We combined model outputs with data on maritime traffic, fishing activity and offshore wind farms to measure the exposure of all the species to these pressures, identifying areas of concern. This study serves as a baseline for the species presence in Irish waters over the last two decades to help develop appropriate marine spatial plans in the future.

Quantifying the spatial nonstationary response of environmental factors on purse seine tuna vessel fishing

To investigate the spatial and temporal patterns of environmental factors influencing the activity of purse seine tuna fishing vessels, data on fishing efforts of purse seine tuna fleets and environmental factors in the Western and Central Pacific Ocean (WCPO) from 2015 to 2020 were utilized to develop a geographically weighted regression (GWR) model. The results showed that fishing activity was primarily concentrated in the area between 140°E and 175°W, and between 10°S and 5°N. The GWR model showed excellent fitting performance and was suitable for correlation analysis. The environmental factors had a significant spatially heterogeneous effect on the fishing activity of purse seine tuna fishing vessels. The sea surface temperature, primary productivity at 200 m depth, and dissolved oxygen below the surface had the greatest spatially heterogeneous effect and are important environmental variables influencing the activity of purse seine tuna vessels in the WCPO. This study provides new methods for exploring the spatial distribution of fishing vessel activity to support science-based conservation and management.

Is nutrition‐sensitive fish farming a panacea for Africa's increasing malnutrition burden? The case of Sierra Leone

AbstractFish is vital for reducing hunger and malnutrition. However, the combined impact of climate change and overfishing is increasing the hunger and malnutrition burden on the African continent and its population of over 200 million people who depend on marine capture fishing and related activities for survival. Fish farming was introduced to alleviate these problems, and our study assessed the extent to which current fish farming activities in the least developed countries (LDCs) like Sierra Leone provide sufficient micro‐ and macro‐nutrients for local communities. The present study which is based on data from 300 survey questionnaires and 77 semi‐structured interviews administered in three communities in Sierra Leone, and from two expert judgments which investigated the nutritional impact of fish farming activities in Sierra Leone, revealed that (1) there is a range of sub‐standard fish farming activities from sampled farms; (2) that these activities could diminish the nutritional quality of farmed fish; and (3) that coastal communities were suspicious of eating or investing in fish farming. To alleviate Africa's increasing malnutrition, burden, our research highlights the need for investment in nutrition‐sensitive fish farming – a refocus from an emphasis on increasing production and income. The nutritional quality of farmed fish is a more basic consideration than the quantity of production for securing a healthy and economically viable fish farming sector for LDCs like Sierra Leone.

Deep learning and machine learning classification technique for integrated forecasting

Smart fisheries are increasingly using artificial intelligence (AI) technologies to increase their sustainability. The potential fishing zone (PFZ) forecasts several fish aggregation zones throughout the duration of the prediction in any sea. The autoregressive integrated moving average (ARIMA) and random forest model are used in the current study to provide a technique for locating viable fishing zones in deep marine seas. A significant amount of data was gathered for the database's creation, including monitoring information for Indian fishing fleets from 2017 to 2019. Using expert label datasets for validation, it was discovered that the model's detection accuracy was 98%. Our method uses salinity and dissolved oxygen, two crucial markers of water quality, to identify suitable fishing zones for the first time. In the current research, a system was created to identify and map the quantity of fishing activity. The tests use a number of parameter measurements to evaluate the contrast-enhanced computed tomography (CECT) approach to machine learning (ML) and deep learning (DL) methodologies. The findings showed that the CECT had a 94% accuracy rate compared to a convolutional neural network's 92% accuracy rate for the 80% training data and 20% testing data.

Effect of solid-state fermentation of Brewer's spent grain on digestibility and digestive function of european seabass (Dicentrarchus labrax) juveniles

This study assessed the effects of dietary inclusion of solid-state fermented (SSF) brewer’s spent grain (BSG) with Aspergillus ibericus on nutrient and energy digestibility, digestive enzyme activity, and intestinal histomorphology of juvenile European seabass (Dicentrarchus labrax). Five diets (18 % crude lipids and 45 % crude protein) were formulated, including a control diet (without BSG), two diets with 10 % and 20 % unfermented BSG (10BSG and 20BSG), and two other diets with 10 % and 20 % fermented BSG (10BSG-SSF and 20BSG-SSF). SSF affected the BSG's nutritional composition, including a 21 % increase in protein content and reductions in lipid (49 %), cellulose (30 %), hemicellulose (34 %), and lignin (7.3 %) content. Antioxidant activity and total phenolic compounds were minimal before SSF but significantly increased after SSF. Dietary incorporation of 20 % BSG-SSF increased the digestibility of dry matter (p<0.01), protein (p=0.03), isoleucine (p=0.03), glutamate (p=0.02), lipids (p=0.04) and energy (p=0.04) compared to the 20BSG diet. Moreover, SSF also modulated digestive enzyme activity, reducing total protease (p=0.03) and trypsin (p=0.01) activities in fish fed the 10BSG-SSF diet compared to the control diet. Fish fed the 20BSG diet showed changes in intestinal histomorphology compared to those fed the control diet, and SSF of BSG appeared to mitigate these effects.Overall, these results indicate that SSF is a promising technique for enhancing the nutritional quality of low-value agro-industrial by-products, such as BSG, increasing their potential use as feed ingredients and contributing to reducing the climate and environmental footprint of aquaculture production.

Developing management plans for sprat (Sprattus sprattus) in the Celtic Sea to advance the ecosystem approach to fisheries

Sprat are commercially valuable and are an important component of the North-East Atlantic ecosystem as major predators of zooplankton, competitors with herring, and prey for piscivorous fish, marine mammals, and seabirds. Despite this, insufficient information exists for Celtic Seas sprat, one of five North-East Atlantic stocks, to estimate stock status. To ensure the sustainable exploitation of sprat, the health of the Celtic Seas ecosystem, and the wider fisheries sector, we conduct a management strategy evaluation to stress test the current single-species advice framework. The aim is to evaluate whether ecosystem objectives can be achieved under single-species maximum sustainable yield and precautionary advice frameworks. An operating model was conditioned on life history theory and strategic information from ecosystem models. We showed that in-year advice using an empirical rule could achieve management objectives and help balance the trade-offs between fishing activities and ecosystem health. The approach allows ecosystem understanding to be incorporated within existing precautionary and maximum sustainable yield frameworks to provide a robust management framework that can meet multiple objectives despite uncertainty.

Pengembangan Pelabuhan Perikanan “Tanjung Adikarto” di Kabupaten Kulonprogo dengan Pendekatan Arsitektur Ekologi

In the context of carrying out fisheries activities, the Tanjung Adikarto Fishing Port does not fully meet the requirements as a Coastal Fishing Port (Type C). Complete facilities such as cold storage, shops, ship maintenance and fishing equipment, as well as places for handling and processing fishery products are still not available, while several other facilities also do not meet adequate standards. In this section, the author will describe the actual conditions of the facilities at Tanjung Adikarto Port and their comparison with the standard facilities that a Coastal Port (Type C) should have. This is the first step to evaluate what needs to be improved in order to increase the capacity and feasibility of the port to support more optimal fishing activities. Observations of the existing condition of the port have revealed several problems that need attention. Buildings that are damaged and uninhabitable are one of the main issues that need to be addressed immediately. The aim is not only to ensure port operations run optimally, but also to align port activities with environmental sustainability, so that their contribution to the community's economy can be realized in a sustainable manner.

Inuit Traditional Ecological Knowledge of Anadromous Arctic Char, iqalukpik (Salvelinus alpinus) Under Changing Climatic Conditions in the Amundsen Gulf, Western Canadian Arctic

Inuit in the western Canadian Arctic have observed climate change impacts in marine and freshwater environments that have resulted in changes in the abundance, movement ecology, and health of Arctic char, iqalukpik (Salvelinus alpinus), with implications for their fisheries. This research was co-designed with Inuit to investigate reported changes in anadromous Arctic char in waters near Ulukhaktok, Northwest Territories, Canada. An analysis of semi-structured interviews with 26 Inuit fishers not only documented changes in Arctic char population abundance, spatial movement, appearance, and taste but also changes in access to the fishery. Over the past several decades and becoming pronounced in recent years, fewer fish and specifically fewer medium-sized fish that are preferred by fishers, have been caught using nets near the settlement, with some showing poor body condition, and others appearing to originate from lakes outside of the expected spatial range, earlier in an extended summer coastal fishing season. Inuit have observed changes in individual fish with broader environmental changes that are also disrupting fishing activities: the increasing prevalence of Pacific salmon, warmer air and marine sea surface temperatures, inconsistent sea and lake ice conditions, stronger and more frequent wind and wave activity, fluctuating water levels in rivers, and a seasonal tunicate bloom. Inuit have responded to these changes by altering personal subsistence fishing practices and temporarily halting a small-scale community-based commercial fishery because of observations in stock declines and in order to prioritize the subsistence fishery.

Rancang Bangun Sistem Monitoring Cuaca Berbasis Google Spreadsheet Untuk Nelayan Di Wilayah Pesisir Pantai

Coastal areas are vital areas for fishing activities, and the weather in this area plays a very important role in the safety and efficiency of fishermen's operations. Fishermen on the coast often face the challenges of weather that is changeable and can be very extreme, including strong winds that can cause high waves and unsafe sea conditions. Therefore, the development of a Google spreadsheet-based weather monitoring system for fishermen in coastal areas is very relevant and strategic to support safer and more productive fishing activities. This research aims to make it easier for fishermen to monitor the weather in coastal areas in real time. Testing is carried out by running the system for observation for a predetermined time duration. This research uses an anemometer, DHT11 and raindrop sensors connected to a NodeMCU ESP32 microcontroller to send data to a Google spreadsheet, with readings of wind speed, temperature, air humidity and rain values. This research was carried out at the Nusantara Prigi fishing port, Trenggalek, challenging the work of anemometer sensors, DHT11 and raindrop sensors. Testing of tools and data obtained by comparing data on wind speed, temperature and air humidity using a digital anemometer and digital thermometer hygrometer humidity. The results of this research are that a Google spreadsheet-based weather monitoring design for fishermen in coastal areas can monitor wind speed, air humidity, temperature and detect rain online using a spreadsheet application and functions well with an average error accuracy of 3%.

Using social media image to identify threatened elasmobranch species caught by a small-scale fishery in a data-poor area.

Sharing fishing activity via social media attracts millions of views. The data from these shares includes key information for a fisheries database such as the species present in the catches and in many cases the number of specimens caught. Many countries in the Global South do not have official information about basic data on fishing activity, especially small-scale activity. In many of such countries like Brazil, overfishing poses a significant threat to numerous threatened species, including elasmobranchs, due to the frailty of fisheries management and law enforcement. The lack of a national (Brazil) data collection program makes sharing data on social media a potential source of fisheries related information. Hence, this study aimed to verify the potential of social media data to describe artisanal fishing and identify elasmobranch species caught by a small-scale fleet in a data-poor Equatorial Southwest Atlantic region. The identification of elasmobranch species was made based on 250 videos shared by local fishers publicly on social media (Youtube™). Among these, sharks and rays were observed in 19 (8%) and 42 (17%) videos, respectively. A total of 98 specimens were recorded, of which 80% could be identified to a species level. Most of the records comprised the stingrays Hypanus berthalutzae and Hypanus guttatus, while Ginglymostoma cirratum was the most recorded shark. More than half of the elasmobranch species recorded are listed at some level of threat according to the IUCN Red List. According to the Brazilian legislation, at least 20% of the species identified in these videos are considered Endangered (EN) or Critically Endangered (CR). Therefore, fishing activity shared via social media can be considered effective in identifying threatened elasmobranch species, as well as providing data on species occurrence, number of specimens, or rare sightings. It is suggested that fishing activity shared via social media be used in parallel with traditional methods (e.g. on-board data and landing observations) to obtain fisheries information and data about endangered species in data poor areas.

Evaluation of Gamma-Aminobutyric Acid (GABA) as a Functional Feed Ingredient on Growth Performance, Immune Enhancement, and Disease Resistance in Olive Flounder (Paralichthys olivaceus) under High Stocking Density.

Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is found in the brain and central nervous system of animals as an inhibitory neurotransmitter. It has been shown to have a variety of physiological functions, including stress reduction and immune enhancement. This study investigated the effects of dietary supplementation with GABA on growth, serum biochemistry, innate immunity, and disease resistance in juvenile olive flounders (Paralichthys olivaceus) challenged with Edwardsiella tarda under high-stocking density. A control diet and three experimental diets were prepared, with 150 mg/kg (GABA150), 200 mg/kg (GABA200), and 250 mg/kg (GABA250) of GABA added to each diet, respectively. Each experimental diet was fed to olive flounders in triplicate with an initial weight of 12.75 g ± 0.3 g in 40 L tanks at two stocking densities: normal density (20 fish/tank) and high density (40 fish/tank). After 8 weeks of the feeding trial, growth, feed utilization, whole-body proximate compositions, blood analyses, and non-specific immune responses were measured, and challenge tests were performed. There were no significant differences in the weight gain (WG) and specific growth rate (SGR) among fish fed the GABA-supplemented diets at the two stocking densities. However, the normal-density groups showed significantly higher WG and SGR than the high-density groups (p < 0.05). There was no significant difference in feed efficiency and protein efficiency ratio among all groups. Moreover, there was no significant difference in the whole-body proximate composition analysis (p > 0.05). There were no significant differences in cortisol levels in fish fed the GABA at both densities, but the high-density group showed a significantly higher cortisol than the low-density group. Blood GABA significantly increased in a dose-dependent manner regardless of the density groups (p < 0.05). Superoxide dismutase activity showed significantly higher levels than the control group, but there was no significant effect of the stocking densities in fish fed the GABA diets (p < 0.05). Myeloperoxidase activities in fish fed the GABA200 and GABA250 diets showed significantly higher levels at both of the stocking densities (p < 0.05). Lysozyme activity was significantly higher in the GABA150 group than in the CON, GABA200, and GABA250 groups (p < 0.05). After 15 days of challenge tests with Edwardsiella tarda, the cumulative survival rates of the GABA150, GABA200, and GABA250 groups were significantly higher than that of the CON group (p < 0.05). The results suggested that the optimal dietary GABA level for juvenile olive flounder culture is 150 mg/kg, regardless of rearing density, to enhance growth, immunity, and disease resistance.

Sustainable management of predatory fish affected by an Allee effect through marine protected areas and taxation

Ecological balance and stable economic development are crucial for the fishery. This study proposes a predator–prey system for marine communities, where the growth of predators follows the Allee effect and takes into account the rapid fluctuations in resource prices caused by supply and demand. The system predicts the existence of catastrophic equilibrium, which may lead to the extinction of prey, consequently leading to the extinction of predators, but fishing efforts remain high. Marine protected areas are established near fishing areas to avoid such situations. Fish migrate rapidly between these two areas and are only harvested in the nonprotected areas. A three-dimensional simplified model is derived by applying variable aggregation to describe the variation of global variables on a slow time scale. To seek conditions to avoid species extinction and maintain sustainable fishing activities, the existence of positive equilibrium points and their local stability are explored based on the simplified model. Moreover, the long-term impact of establishing marine protected areas and levying taxes based on unit catch on fishery dynamics is studied, and the optimal tax policy is obtained by applying Pontryagin’s maximum principle. The theoretical analysis and numerical examples of this study demonstrate the comprehensive effectiveness of increasing the proportion of marine protected areas and controlling taxes on the sustainable development of fishery.

Dietary chitosan positively influences the immunity and reproductive performances of mature silver barb (Barbonymus gonionotus)

This research was carried out to assess the effects of dietary chitosan on the immunity and reproductive performance of adult Barbonymus gonionotus. The fish (average weight 66.7 ± 0. 86 g) were randomly divided into four treatments: control (0.00 g/kg), CHT-1 (1.00 g/kg), CHT-2 (2.00 g/kg) and CHT-3 (3.00 g/kg) and were fed the appropriately formulated diets for 60 days. The results showed significant differences in the immunological parameters such as lymphocytes, neutrophils, monocytes, immunoglobulin (IgM), and lysozyme activity in the chitosan-fed fish compared to those in the control diet-fed fish. The reproductive hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were significantly enhanced in chitosan fed fish compared to the control. Furthermore, the chitosan-treated diet significantly improved the reproductive performance of adult B. gonionotus compared to control fish. Qualitative histological studies showed that chitosan significantly improved egg morphology and showed mature and uniformly sized eggs compared to the control fish. Similarly, a quantitative histological investigation revealed that chitosan significantly increased oocyte area (µm2) and number of oocyte-3 compared to the control. In conclusion, our study found that dietary chitosan at optimal dose of 1.00 g chitosan/kg feed enhanced immunity, regulated reproductive hormone levels, and promoted reproductive performance and ovarian development in B. gonionotus.

KAPASITAS PERIKANAN CANTRANG DI PELABUHAN PERIKANAN PANTAI TEGALSARI KOTA TEGAL PROVINSI JAWA TENGAH PADA PENGELOLAAN PERIKANAN DEMERSAL

Demersal fish resources are one of the main commodities in the waters of the Java Sea. Tegalsari coastal fishing port is one of the fish landing locations around the Java Sea where most of the demersal commodities landed at the port were caught by cantrang fishing gear. Generally, every fishing activity expects ideal catches by using an efficient input. Technical efficiency can be used as an indicator of performance measurement of fishing gear. This study aimed to determine the fishing capacity of cantrang fisheries in Tegalsari fishing port. The fishing capacity analysis was carried out using fish landing data from PPP Tegalsari from 2008 to 2019. The measurement of technical efficiency by using the DEA (Data Envelopment Analysis) approach. The result showed that fishing capacity in 2013, 2015, 2017, 2018, and 2019 have to be maintained because it is in a fully utilized, and the rest of them were overcapacity caused by an excess capacity of the value of fishing gear and number of efforts. Keywords: Data Envelopment Analysis, Decision Making Unit, fish resources, fishing efficiency, Java Sea-Indonesia

Digital sailmate: enhancing safety through low-cost stability monitoring in artisanal fishing

Despite overall mortality decreasing, offshore fishing remains one of the riskiest work-based activities worldwide. For example, fishing communities in East Africa have a 43-fold higher rate of drowning than the general population. A lack of safety culture and knowledge around vessel stability contributes to this issue. Formal safety measures can be difficult to enforce, especially in small scale and subsistence fishing activities dominated by small artisanal boats. Digital technologies hold potential to effectively improve fishing safety. A digital safety device based on commonly held and relatively low-cost consumer products such as smartphones can provide increasing information to fishers enabling more informed safety decisions to be taken during vessel use. This paper proposes the algorithms for a prototype device to monitor stability of fishing vessels, with focus on the capabilities of low-fidelity data in stability assessment. The findings of experimental results at model and full scale are presented. The research indicates that an inclining test can be carried out with minimal training or knowledge base to allow an adequate stability assessment of a vessel before departure on a fishing trip. This baseline measure can then be used to track stability whilst underway as vessel motion is recorded and processed continually updating the stability assessment.

The complementary relationship between illegal fishing and maritime piracy: A case study of the Gulf of Guinea

This research paper investigates the interrelationship between maritime crime, specifically sea piracy, and illegal fishing. Existing studies primarily focus on the link between piracy and illegal fishing activities carried out by foreign trawlers, drawing evidence from Somali piracy cases. A causal narrative in past works highlights the detrimental effects of foreign trawlers on local marine resources, ecosystems, and livelihoods, thereby driving local fishers to turn toward piracy and prompting coastal states to address the key issue of illegal fishing by foreign vessels.However, this emphasis on external perpetrators can lead states to pay less attention to local actors involved in illegal fishing and maritime piracy. Therefore, this study redirects our attention to local perpetrators who engage in illegal fishing and maritime piracy. It explores the complementary relationship between these two types of crimes. Our findings indicate that reducing illegal fishing activities in a local area enhances the likelihood of maritime piracy occurrence. By shedding light on the complementarity between illegal fishing and maritime piracy, this research provides valuable insights for policymakers and law enforcement agencies involved in combating maritime crime. It underscores the importance of locally addressing illegal fishing and piracy using a more holistic approach.

Behavioral and electrocardiographic evaluation of Colossoma macropomum (Cuvier, 1818) indicates a safe concentration window for the use of Spilanthol in immersion baths

The use of natural products for the sedation and anesthesia of fish is already well established, with characteristics similar to or potentially superior to synthetic anesthetics. There is a significant advantage in terms of commercial accessibility compared to synthetic drugs, without compromising effectiveness and safety. Var. Oleracea, commonly known as jambu, is considered a medicinal plant. It contains spilanthol, an olefinic N-alkyl-amide with an isobutyl side chain. The supercritical oil of Spilanthes acmella (SOSA) exhibits anesthetic and sedative activity in fish. Our study aimed to evaluate the behavior and cardiac activity (ECG) of SOSA in seven groups: control, control vehicle, 20, 30, 40, 50 and 60 μL.L−1 in tambaqui (Colossoma macropomum). The animals were divided into two experiments: Experiment 1 (Behavioral), in which the latency for the loss and recovery of the animals' posture reflex in contact with the concentrations was evaluated. Experiment 2 (ECG), in which morphographic changes in the ECG were identified during treatment with various concentrations of SOSA. We conclude that concentrations of 20 μL.L−1 to 40 μL.L−1of SOSA were the most suitable for anesthesia due to the rapid reversibility of effects and minimal changes in the hemodynamics of C. macropomum in short-duration anesthesia.

STATUS PEMANFAATAN IKAN KAKAP (Lutjanus spp.) BERBASIS DATA PANJANG IKAN DI PERAIRAN TAMAN NASIONAL TAKA BONERATE

Snappers (Lutjanus spp.) are the most common reef fish caught in Taka Bonerate National Park due to its high economic value and primarily targeted species. Without proper management measures, intensive fishing activities might result in unsustainable fish stocks. Therefore, in order to maintain sustainable utilization, it is important to understand the stock status of snapper fisheries. This study aimed to analyze the snappers' stock status in Taka Bonerate National Park's waters. Data were collected from January to December 2022 at three small-scale fisheries landing sites. The results showed that snappers are classified as slow-growing species with growth rates for species L. bohar, L. quinquelineatus, L. gibbus respectively 0,12, 0,39, and 0,35 per year to reach their respective asymptotic lengths of 83,41 cm, 29,5 cm, and 46,80 cm. The stock status of L. gibbus and L. bohar were indicated at overfished status where the exploitation rate (E) was &gt; 0.5 and the SPR was &lt; 0.3, hence a proper management measures is required. Furthermore, the species of L. quinquelineatus has a value of E is 0.5 and SPR is at 0.3, indicating that the utilization level of this species was at an optimal level. Keywords: Snapper, Taka Bonerate, Fisheries Management.

Implementasi Kebijakan Penanganan dan Penanggulangan Kegiatan Penangkapan Ikan yang Merusak (Destructive Fishing) di Indonesia

Destructive fishing activities are a threat to the sustainability of fishery resources and harm fish stocks as well as environmental ecosystems. Comprehensive regulations are needed to cope with destructive fishing and ensure the regulations will be implemented well and appropriately. Using a qualitative approach, this study aims to scrutinize the implementation of policies issued by the central government in the regions, including laws and other national regulations related to coping with destructive fishing. North Maluku Province is the focus of the study to identify the implementation of national regulations in the region. In addition, this study also identifies the roles of maritime law enforcement agencies involved in efforts to supervise and implement national policies related to overcoming and preventing destructive fishing. The results reveal that existing laws are insufficient to cope with the destructive fishing criminal act. So far, eight actors have roles in the prevention and coping of destructive fishing activities, consisting of elements of maritime law enforcement agencies such as the Police, Indonesian Navy, Indonesian Coast Guard, and Directorate General of PSDKP, as well as civil or community elements such as the PWP3K Special Police, Forestry Police, Department of Marine Affairs and Fisheries, and Monitoring Community Supervisory Groups (Pokmaswas). Keywords: destructive fishing, Law, Maritime Law Agency, Gap

Molecular characterization, expression analysis and function identification of Pf_IL-12p35, Pf_IL-23p19 and Pf_IL-12p40 genes in yellow catfish (Pelteobagrus fulvidraco)

The interleukin-12 (IL-12) family is a class of heterodimeric cytokines that play crucial roles in pro-inflammatory and pro-stimulatory responses. Although some IL-12 and IL-23 paralogues have been found in fish, their functional activity in fish remains poorly understood. In this study, Pf_IL-12p35a/b, Pf_IL-23p19 and Pf_IL-12p40a/b/c genes were cloned from yellow catfish (Pelteobagrus fulvidraco), four α-helices were found in Pf_IL-12p35a/b and Pf_IL-23p19. The transcripts of these six genes were relatively high in mucus and immune tissues of healthy individuals, and in gill leukocytes. Following Edwardsiella ictaluri infection, Pf_IL-12p35a/b and Pf_IL-23p19 mRNAs were induced in brain and kidney (or head kidney), Pf_IL-12p40a mRNA was induced in gill, and Pf_IL-12p40b/c mRNAs were induced in brain and liver (or skin). The mRNA expression of these genes in PBLs was induced by phytohaemagglutinin (PHA) and polyinosinic-polycytidylic acid (poly I:C), while lipopolysaccharides (LPS) induced the mRNA expression of Pf_IL-12p35a and Pf_IL-12p40b/c in PBLs. After stimulation with recombinant (r) Pf_IL-12 and rPf_IL-23 subunit proteins, either alone or in combination, mRNA expression patterns of genes related to T helper cell development exhibited distinct differences. The results suggest that Pf_IL-12 and Pf_IL-23 subunits may play important roles in regulating immune responses to pathogens and T helper cell development.