Fish Production Research Articles

Fish products market of the Kamchatka Region: features of activities, implementations and problems

The article is devoted to the study of the characteristics of the fishery market in the Kamchatka Territory, which is one of the key regions of Russia for the extraction and processing of aquatic biological resources (ABR). The study includes a detailed analysis of the production of various types of FBR. The directions for the sale of fish products, both on the domestic market of Russia and on international markets, are discussed, identifying the main export directions and barriers that arise in conditions of foreign economic instability and sanctions pressure. Particular attention is paid to the dynamics of the consumer price index (CPI) for fish products, including factors influencing price increases.

Comparison of the trophic sources and pathways of mesozooplankton and ichthyoplankton in the Kuroshio current and its neighboring waters

Commercially important fish spend their vulnerable early life stages in the Kuroshio Current, resulting in high fishery production even in the vicinity of poor prey availability under oligotrophic conditions. Nevertheless, little information is available on how ichthyoplankton are supported by trophodynamics in complicated food webs. Here, we have explored trophic sources and pathways toward ichthyoplankton in the Kuroshio and its neighboring waters based on metabarcoding analysis of gut DNA content for major taxonomic groups of mesozooplankton and ichthyoplankton. Calanoids were found to be the most predominant and frequently appearing prey, whereas non-crustaceans were the secondary prey for most mesozooplankton and ichthyoplankton groups. Trophic networks based on gut DNA content demonstrated that calanoids were the most important sector with multiple linkages among their prey and predators, and gelatinous and non-crustacean mesozooplankton were the secondary sectors. These findings suggest that calanoids are important hubs of trophic pathways toward ichthyoplankton, and that gelatinous and non-crustacean mesozooplankton groups strengthen trophic relationships with multiple components. Contrary to general thought, our metabarcoding analysis has revealed that trophodynamics toward ichthyoplankton are not strongly dependent on the grazing food chain, but are supported by multiple trophic pathways in the Kuroshio and its neighboring waters.

PRODUK OLAHAN IKAN (PROKAN) UPAYA MENINGKATKAN INOVASI PRODUK PERIKANAN DI DESA SISARAHILI TELUK SIABANG, KECAMATAN SAWO, KABUPATEN NIAS UTARA

Sisarahili Village is one of the underdeveloped villages that has a lot of potential in the fisheries sector. Based on survey information in the village, the income and economy of the people of Sisarahili Teluk Siabang Village have decreased since the Covid-19 pandemic in 2020. The problem faced by the community in Sisarahili Teluk Siabang Village is the lack of knowledge and skills possessed by the community to process fishery products into processed fish products that are highly nutritious and have high selling value. In order to solve this problem, this service activity aims to provide knowledge and skills to the community in Sisarahili Teluk Siabang Village about the technology of processing fishery products into processed fish products (PROKAN) which are highly nutritious and can increase the income and economy of the community. The implementation method used to achieve the target of service activities is by conducting counseling, training on the technology of processing fishery products into Processed Fish Products (PROKAN): nuggets and meatballs and mentoring. The community group that is the special target of this service activity is fisherwomen. Through the Student Organization Capacity Strengthening Program (PPK ORMAWA), it becomes a student movement in providing knowledge about the technology of processing fishery products into Processed Fish Products (PROKAN). This community service activity was welcomed enthusiastically by the community by attending the counseling and training of Processed Fish Products (PROKAN). The community stated that they got additional insights and skills in processing fish into various products, namely nuggets and meatballs.

PENERAPAN BLUE ECONOMY DALAM PENGEMBANGAN PENDAPATAN PELAKU USAHA PERIKANAN DI KAMPUNG HAMADI KOTA JAYAPURA

Processed products in Hamadi Village only rely on the type of processed fish smoked produced by Fishery Business Actors, namely POKLAHSAR Mama Papua. Efforts to maximize the acceptance of processed fishery products and meet market demands can be done by improving the appearance of the product, so that old buyers want to buy more products with a new appearance both in terms of shape, size, style, packaging, and taste. This can be done by making other breakthroughs such as value-added processed fishery products. This program used PRA (Participatory Rural Appraisal) method is one of the methods that can be applied. After getting pretest and posttest scores, must conduct an analysis to get the score obtained. The analysis used is uji normalitas gain. This test is used to determine the effectiveness of the treatment given. Implementation of community partnership service activities to POKLAHSAR Mama Papua in Hamadi village with providing training in the manufacture of a variety of processed fishery products. A variety of processed fishery products that have been made such as; Meatballs, Shredded Fish, Suir-Suir and Sambal whose meat is from Yellow Fin Tuna (Thunnus albacares). Furthermore, make packaging for a variety of processed fisheries and don't forget to teach partners about the importance of making simple bookkeeping by making pre-test and post test about bookkeeping knowledge. Then socialization about making NIB (Nomor Izin Berusaha) online and training in making social media in marketing a variety of processed fishery products, This is done to increase income POKLAHSAR Mama Papua in Hamadi village.

Assessing Listeria monocytogenes Growth in Artificially Inoculated Sea-Farmed Product—Raw Sea Bass (Dicentrarchus labrax) Fillet, Produced in Greece

Listeria monocytogenes (Lm) is responsible for listeriosis, a serious foodborne disease, with high hospitalization and mortality rates worldwide. The main cause of listeriosis in humans is the consumption of ready-to-eat (RTE) foods; Commission Regulation (EC) No 2073/2005 establishes microbiological criteria for Lm in RTE foods. Raw fish products are widely consumed, e.g., in sushi and various seafood recipes (e.g., carpaccio, sashimi, maki, nigiri, tartare, etc.), but are not subjected to RTE food safety criteria. The aim of our study was to assess the growth potential of Lm in raw sea bass fillets obtained from a leading aquaculture company in Greece. In order to assess the growth of Lm in raw sea bass fillets, we applied the “challenge test”, a scientific experiment designed to assess the growth of Lm within a specific food product under controlled conditions. According to our results, and taking into consideration the health risk for the listeriosis-vulnerable population, raw fish products utilized in the preparation of RTE foods, including sushi and an array of seafood dishes, should be incorporated in the Category of Safety Criteria of Regulation (EC) No 2073/2005 “Ready-to-eat food able to support the growth of Listeria monocytogenes”.

Joint cultivation of fish and vegetable crops in an aquaponics system using floating beds

Comparative results of the cultivation of Silver crucian carp in conditions of aquarium circulation systems are presented, in one of which aquaponic cultivation of tomatoes and peppers on a floating bed in a fish tank was used. In comparison with the control, a significant improvement in hydrochemical parameters for dissolved oxygen and a group of nitrogen-containing compounds was noted in the experimental aquarium. The ratio of the specific formation as a result of the vital activity of fish and the absorption of nitrates by plants was 0,8 units. The results showed that for 1 kg of ichthyomass, 26 tomato plants or 34 bell pepper bushes can be planted on a floating bed. In the obtained fruits, the nitrate content turned out to be 2 times lower than the MPC for open and 4 times lower than the MPC for protected soil. The increase in the total ichthyomass of crucians in the experiment turned out to be 1,6 times higher, and feed costs 1,5 times lower than in the control. At the same time, the fish productivity of the aquarium with a floating vegetable garden increased by 9,7%.

Herbicide paraquat dichloride augments the expression of the c-abl-noxa-apoptotic pathway, instigating ovarian atresia in edible fish, Channa punctatus.

Ovarian cells of animals undergo atresia to regulate egg numbers and their release. However, unrestrained atretic activity decreases the chances of oocyte maturity and further process, ultimately resulting in a reduced population. Edible fishes are a critical source of nutrition and it is required to regulate their population. The application of herbicides at fish production sites is a threat to their population by altering female reproductive activity. In concern to this, here, this 60-day study investigates herbicide paraquat dichloride (PD)-induced atresia in ovarian cells of Channa punctatus (C. punctatus). Further, 96-h LC50 of PD for C. punctatus was calculated as 58.40mg/L. At the end of each exposure period, an increase in intracellular ROS in blood cells and activities of SOD and CAT in ovary tissue were observed in PD-treated fish with increasing concentration. The frequency of micronuclei in blood cells subsequently increased with the highest PD concentration. A significant (p < 0.05) increase in the relative expression of target genes was observed at the 30th and 60th day of the sampling periods in the fish treated with the highest concentration of PD. The histological study confirmed the occurrence of atretic ovary cells in PD-exposed fish. From the results it can be concluded that PD enhances the uncontrolled death of ovarian cells and has consequences of impairing the ovary health and reproductive potential of fish, hence reducing the fish population.

Trends in the development of the fisheries complex and consumption of fish products in the country

The purpose of the work is to analyze current trends in the development of the Russian fisheries complex and identify the causes of the stagnant dynamics of consumption of fish products by the population.Methods used: general scientific research methods, as well as methods of statistical analysis of time series, graphical and coefficient methods.The element of novelty: The current interdependence between the dynamics of fish catch, the actual financial results of economic activities of enterprises, as well as the general level of consumption of fish products by the population has been revealed. The study based on quantitative analysis complements the existing economic theory with new empirical data necessary to clarify the current directions of development of the country’s fisheries complex for its sustainable development.The results of the study: the actual catch of fish in Russia, which reached its historical maximum in modern history of 5.3 million tons in 2023, with simultaneously high levels of exports of fish products, provided an increased level of profitability of economic activities of enterprises and an increase in their financial independence in comparison with other sectors of the economy, however, the studied trends in the development of the fisheries complex were not broadcast in advance the increase in consumption of fish products by the population, in particular, from 2010 to 2022.Practical significance: the obtained research results and empirical data can be used by the authorities in developing relevant directions for the sustainable development of the country’s fisheries complex.

Shellfishing, sea levels, and the earliest Native American villages (5000–3800 yrs. BP) of the South Atlantic Coast of the U.S

Shell ring archaeological sites are one of the most visible site types along the lower South Atlantic Coast of the United States. These cultural sites are large, circular to arcuate piles of mollusk shells with some reaching over three meters in elevation and over 100 m in diameter. They are comprised largely of mollusk shells (e.g., Eastern oyster, Crassostrea virginica), but also contain early pottery, nonhuman faunal remains, and other artifacts. Our work establishes that they represent the earliest widespread Native American villages occupied year-round in the Eastern Woodlands of North America. Significantly, our results from sea-level modelling and isotope geochemistry on mollusks establish that the inhabitants of these earliest villages (ca. 5000–3800 yrs. BP) lived within a fluctuating coastal environment, harvested certain resources year-round, and targeted diverse habitats across the estuaries. Both the growth and decline of these earliest villages are associated with a concomitant rise and lowering of sea level that impacted the productivity of the oyster reef fishery along the South Atlantic Coast. Despite these large-scale environmental changes, this research indicates that Native American fishing villages persisted along the coast for over 1000 years.

Nutrition of the Baikal seal and its role in the trophic structure of the Baikal ecosystem

The purpose of the work was to give as complete an overview as possible of the currently available publications related to the nutrition of the Baikal seal (Pusa sibirica).More than 50 sources devoted to the stated topic served as materials for writing the review.The results of the analysis of published sources showed that the Baikal seal feeds mainly on 4–6 species of small pelagic fish throughout the year, and the main food is two species of golomyankas of the Comephoridae family. The hypothesis according to which the well-being of the species is largely determined by the use of the pelagic crustacean Macrochectopus branickii for food does not stand up to criticism and is unlikely to reflect the real picture. The distribution of the Baikal omul is such that it does not exclude, but does not in any way contribute to the fact that the seal consumes it in significant quantities. However, the consumption of salmonids as food has become more frequent in recent years (the reasons for this cannot be established), but even now these fish constitute &lt;3% of the biomass of fish consumed by the entire population of the Baikal seal per year. All adaptive morphophysiological, anatomical and behavioral features of the species clearly indicate that the seal has developed a food strategy aimed at the effective production and utilization of the above-mentioned fish species.Conclusion: the basis of the diet of the Baikal seal is made up of small non-commercial pelagic fish species, therefore, even with a large population, seals cannot be the reason for the reduction in commercial omul stocks.The practical significance of the work lies in the fact that its conclusions must be taken into account when developing rules and strategies for exploiting the Baikal seal population.

Nationwide survey in Korea for risk assessment of pesticide residues in fishery and seaweed products

Pesticide residues in fishery products are a concern due to environmental contamination. However, it is not sufficiently managed because of a lack of established standards. This study was conducted to monitor pesticide residues in fishery and seaweed product samples and assess the risk to humans. A total of 454 fishery products and 38 seaweed products were examined, and seven pesticides were detected. Among these, ethoxyquin was the most frequently detected. The risk of ethoxyquin via chronic exposure was 0.16 % and 83 % for the average and 97.5th intake, respectively. A risk exceeding 80 % is concerning; however, this concentration is considered safe in real-world circumstances, such as washing and cooking processes. Therefore, the detected pesticide residues in this study were assessed to be safe level for Korean intake level of fishery products. However, DDT, the prohibited pesticide decades ago, was still found and it is necessary to keep monitor considering persistent of pesticides. Considering newly regulated pesticides, sufficient monitoring and risk assessment data such as this study should be provided for policy standards setting and management.

Dietary overlap of invasive cyprinids and common carp in fishponds of Central Europe

Freshwater fishponds are an important part of the global aquaculture fish production, but they also are a source of invasive species with potentially negative impacts on pond ecosystems. In this study, we investigated dietary competition between common carp (Cyprinus carpio) and two invasive cyprinids, Pseudorasbora parva and Carassius gibelio, in fishponds of Central Europe. Using δ13C and δ15N stable isotopes analysis, we evaluated the extent of isotopic niche overlaps and the utilization of dietary sources by these species in fishponds that differ in the intensity of fish production. The isotopic niche of C. carpio and the invasive cyprinids overlap more in ponds with intensive (south-eastern Czechia) and semi-intensive (northern Austria) fish production then in ponds with low intensity production (eastern Slovakia). Our results also suggest that both invasive species opportunistically adjust their diet to their gape size and that they predominantly assimilate dietary energy from zooplankton and macroinvertebrates rather than from primary producers and detritus. Our study highlights the high potential of these invasive cyprinids to compete with C. carpio in fishponds of Central Europe.

Framework assessment of sustainability: Methodology for evaluating the conformance of fishery and aquaculture management systems to FAO guidelines

Sustainability is about meeting the needs of current generations without compromising those of future generations. For fished and aquacultured products, sustainability is often gauged on an individual fishery or farm basis but can be driven by a well-designed and implemented regulatory management system, or set of laws, rules, and policies promulgated by a governmental entity. To achieve global coverage via current assessment approaches requires enormous effort and resources due to the sheer number of individual operating units. System assessments are well established in assuring seafood safety, but much less so in regard to sustainability. This paper presents a tool to measure sustainability based on the prevailing regulatory management system and invites other researchers and practitioners to gauge the applicability of the methodology to new contexts. Evaluating how management systems support sustainable practices is key for assessing current reality and planning change. The methodology presented is based on international criteria for sustainability set forth in United Nations Food and Agriculture Organization (FAO) guidelines for the ecolabelling of fish and fishery products as well as aquaculture certification. The assessment tools are the distillation of qualitative criteria found within the FAO guidelines into simple propositions called “Topics of Pertinence” that enable a straightforward cross-checking of whether the requirements and provisions of regulatory management systems reflect broadly accepted sustainability criteria in fisheries and aquaculture sectors. Assessments document what management systems aim to do via laws, regulations, and policies, and verify mechanisms within the systems that support implementation and compliance. While other sustainability assessments exist, the methodology described here is unique in that it is the only process that provides a system-based approach targeting higher management levels, which can increase global coverage of sustainability assessment from the current lower-tiered approach of certifying at individual production entities.

Immunostimulant In Fish Hatchery- A Tool In Pharmacological Research

Fish is an aquatic animal that is used as food and presently they are used in scientific research. They provide a simple system for biomedical research and hence there is an increase in demand for fish production due to its dynamic purposes. The fish are less sentient and they have a high potency with the homology of mammals hence they are used as a model in pharmacological research. The various fish that are used are zebra fish, rainbow trout fish, medaka fish, etc. Various husbandry techniques were introduced to increase the production of fish. Their intensification led to poor-quality of fish production. Immunostimulants are drugs that enhance the innate immunity of fish and increase their resistance to the disease. They are biological and synthetic compounds that increase phagocytic, lysosomal, and bactericidal activity by directly activating the immune cells and NK cells and helping in the control of disease. They are used in the pharmacological research of toxicology, genetics, cancer research, biomedicine, neurobiology, endocrinology, ecology, and gerontology, and also in the development of biology and act as a model to provide elemental knowledge on biological science.

Exploring economic viability: A study on profitability and resource efficiency in Polycarp production within the fish super zone of Dhanusha district, Nepal

Dhanusha district of Nepal is recognized as a fish hub of the country still operative fish farming in a semi-commercial level. This study evaluated and analyzed the profitability and resources utilization efficiency in the Polycarp production within the fish super zone of Dhanusha district. Along with it, the study covers socio-demographic characteristic of respondent, determine the factor affecting fish production, rank such challenges based on farmer’s experience, and evaluate returns to scale fish production of this site. 64 farmers were randomly selected and surveyed through a semi-structured questionnaire. In order to collect primary data, pre-tested interview schedule, focus group discussion, key informant Interview, and field survey were conducted. Secondary data were collected by reviewing relevant publications. Analysis of socio-demographic data revealed a predominantly male participation rate (98.44%), with overall aged between 30 and 50 years, among whom the Yadav caste showed maximum engagement (27%). Regarding land ownership, the majority (68.76%) leased land for this activity. Carp polyculture exhibited an average water surface area of 1.55 hectares. The average yearly cost of producing carp fish was Rs.1069644.00, or Rs. 891370.00 per hectare of water surface, per year with fixed costs 15.55% and variable costs 84.45%. Notably, feed costs constituted the largest expense at 49.87%, followed by labor (15.52%) and fingerlings (9.40%). Silver carp emerged as the primary market contributor, comprising 22.96% of total production (6010 kg), followed by common carp, Grass carp, Rohu, Naini, Bighead carp, and Bhakur. Net returns per hectare was Rs. 2,24,348.87, with a resulting B:C ratio of 1.33, indicating economic viability. Challenges identified in the study area included the timely unavailability of fingerling, high feed cost and theft.

Effects of feeding regime on growth, production, and economics of Oreochromine cichlids (Oreochromis mossambicus) in earthen ponds of Bangladesh

The experiment was carried out to evaluate the effects of feeding frequency on the growth, production, and economic aspects of Oreochromine cichlids (Oreochromis mossambicus) in nine earthen ponds for 120 days. Three different feeding regimes (T1, T2, and T3) with three replications each were used. The stocking density was uniform across all treatments at 25,000 fish per hectare. The fish were fed a commercially available pelleted feed with the same feeding rate in all treatments, but the feeding frequency varied. The feeding rate was 10%, 8%, 7%, 6 %, 5%, and 4% which was consecutively adjusted after each fortnightly sampling and 3% for the last 4 weeks of the study period. Feeding frequencies were once a day for T1, twice a day for T2, and three times a day for T3. The average weight gain of Oreochromine cichlids in T3 (295±5 gm) was significantly higher (P&lt;0.05) than those of T2 (240.67±6.66 gm) and T1 (217.17±7.64 gm). The survival rates were 95.20%, 96.99%, and 97.33% for T1, T2, and T3, respectively. The net production of fish in T3 (2882.00±62.00 kg/ha) was significantly higher (P&lt;0.05) than in T2 (2413.00± kg/ha) and T1 (2223±30.55). Furthermore, the highest net return (USD 1163/ha with a cost-benefit ratio of 1.42) was achieved from T3, followed by T2 (USD 527/ha with a cost-benefit ratio of 1.19) and T1 (USD 270/ha with a cost-benefit ratio of 1.09). The results demonstrated that increasing the feeding frequency has positive effects on the growth and production of Oreochromine cichlids.

Multi-tier captive relations in the global value chain of tuna: The case of Fair Trade certification of small-scale tuna fishery in Indonesia

Voluntary sustainability standards have been used as a governance mechanism to ensure the sustainability of fisheries products traded from developing countries. Different standards have become market forces that actors along the value chain are expected to follow to access markets and remain competitive. Recent attention is also being paid to small-scale fisheries, but there is relatively little information about the efficacy of the translation of standards by all actors in the value chain. This study examines how a voluntary sustainability standard is translated from an international buyer down to the producer and the effectiveness of this on social and environmental sustainability. The global value chain (GVC) modular framework is applied to assess the implementation of and compliance with the standard. The analysis is done at the micro, meso, and macro levels. We use the first-ever Fair Trade USA certification for handline small-scale tuna fishery in Maluku, Indonesia, as our case study. The findings indicate that the captive forms of governance prevailing at the micro and meso levels of the value chain vary considerably. This adds a layer of complexity to the extent to which a sustainability standard changes the structure and governance of the value chain. The efficacy of such changes in promoting social and environmental sustainability is constrained by the unequal power dynamics among the various actors operating at the different levels. The findings from this study may contribute to optimizing the value chain for greater sustainability outcomes by involving local actors and accommodating various governance mechanisms to organize the value chain.

Fluorescent-based bile acid triazole-phenothiazine derivatives: Multiphase detection of biogenic amines and application in spoiled foods

Amines are ubiquitous in biological world, yet are toxic and harmful in nature. To preserve the quality and safety of these packaged meals, it’s critical to identify biogenic amines that are emitted from spoiled meat, fish, or dairy products. To this endeavour, herein we report bile acid based triazole derivative with phenothiazine that are capable of sensing various amines by rapid change of fluorescence colour or intensity. The triazole derivatives exhibit a multiphase sensing platform by effectively sensing amine vapours or solutions in both solid and solution phases. Probes in the vapour state exhibit very quick interaction to primary amines (26 s for CTPTZ) and strong sensitivity to putrescine, which is a common example of biogenic amines (BAs). We have employed our unique sensing triazole derivative as a spoilage indication for meat. It detects biogenic amines from spoiled food and produces an optical response. Significant changes in both visual and luminescent were noted within 4–18 h of packaging at room temperature (∼25 °C). The rapid response that biogenic amines provide to these molecular sensors makes them highly promising for applications in the food packaging industry, medical diagnostics, and other sensory devices.

Dmrt1 Is Responsible for Androgen-Induced Masculinization in Nile Tilapia.

17α-Methyltestosterone (MT) is a widely used androgen for all-male fish production in aquaculture. However, the molecular mechanism underlying MT-induced masculinization remains unclear. In this study, we aim to identify the key gene responsible for MT-induced masculinization using the Nile tilapia (Oreochromis niloticus) amhy, dmrt1, and gsdf mutants, which exhibit male-to-female sex reversal. Nile tilapia fry from these three mutant lines were treated with 50 μg/g MT from 5 to 30 days after hatching (dah). The results showed that amhy and gsdf mutants, but not dmrt1 mutants, were masculinized by the MT treatment. Gonadal transcriptome analysis revealed that genes involved in steroidogenesis and germ cell development in MT-treated dmrt1 mutants exhibited a similar expression pattern to that of the wild type (WT) XX. In addition, the dmrt1 mutants cannot be masculinized by co-treatment with MT and the aromatase inhibitor fadrozole. The MT treatment completely blocked early steroidogenic enzyme (Star2, Cyp17a2, and Cyp19a1a) expression independent of amhy, gsdf, and dmrt1. A luciferase analysis showed that MT directly suppressed basal and Sf-1-activated cyp19a1a promoter activity through ara and arb in cultured HEK293 cells. Furthermore, MT treatment inhibited germ cell proliferation in amhy and gsdf mutants but not in dmrt1 mutants. Consistently, dmrt1 expression was induced in MT-treated WT XX, -amhy, and -gsdf mutants. Taken together, these results suggest that dmrt1 is indispensable for MT-induced masculinization in Nile tilapia and that MT functions by inhibiting early steroid synthesis and activating dmrt1 to promote testis development.

Identification of Key Volatile Compounds in Tilapia during Air Frying Process by Quantitative Gas Chromatography-Ion Mobility Spectrometry.

Air frying as a new roasting technology has potential for roasted fish production. In this study, the changes in volatile compounds (VCs) during air frying of tilapia were studied by quantitative gas chromatography-ion mobility spectrometry, followed by the identification of key VCs based on their odor activity value (OAV). There were 34 verified VCs, of which 16 VCs were identified as the key VCs with OAV ≥ 1. Most of the VCs were improved by air frying and peaked at 20 min. During the air frying, the total sulfhydryl content markedly decreased, while the protein carbonyl and MDA content significantly increased, suggesting the enhancement in the oxidation of lipids and proteins. The correlation network among the chemical properties and key VCs was constructed. The change in total sulfhydryl, protein carbonyl, and MDA showed significant correlation with most of the key VCs, especially 2-methyl butanal, ethyl acetate, and propanal. The results indicated that the oxidation of lipids and proteins contributed the most to the flavor improvement in air-fried tilapia. This study provides a crucial reference for the volatile flavor improvement and pre-cooked product development of roasted tilapia.