Surplus Production Research Articles

Fruits and vegetables dietary intake and its estimated consumption among adults receiving antiretroviral therapy in health facilities in Northcentral Ethiopia: a multi-facility cross-sectional study.

Despite the significant role of fruit and vegetables (FAVs) in preventing a variety of chronic diseases and their potential to bolster immune responses and slow the progression of HIV infection to AIDS, there is a lack of studies on the dietary intake of FAVs among HIV-infected adults in Africa, including Ethiopia. Hence, this study aimed to investigate the magnitude of FAV intake and estimated consumption among HIV-infected adults receiving antiretroviral therapy (ART) in northcentral Ethiopia. A multifacility cross-sectional study was conducted on the FAV intake among 865 HIV-infected adults receiving ART. A Poisson regression model with robust variance was used to identify factors associated with FAVs dietary intake. The study indicated that 655 (76.34%; 95% CI: 73.38, 79.07) HIV-infected adults reported consuming FAVs less than once per day, with 838 (97.67%, 95% CI: 96.41, 98.49) and 676 (78.79%, 95% CI: 75.92, 81.40) HIV-infected adults reporting consuming fruits and vegetables less than once per day, respectively. The median (IQR) total FAV intake was 271.3 (IQR: 92.5, 439.5) g/day, with the median (IQR) intake of fruits being 248.1 (IQR: 100.0, 400.0) g/day and vegetables being 273.78 (IQR: 82.44, 348.33) g/day, respectively. We found that being divorced (APR = 1.57, 95% CI: 1.16, 2.12), employed as a daily laborer (APR = 2.08, 95% CI: 1.36, 3.20), being employed (APR = 1.77, 95% CI: 1.10, 2.84), merchants (APR = 1.59, 95% CI: 1.03, 2.47), having children as caregivers (APR = 1.61, 95% CI: 1.02, 2.55), an advanced WHO clinical stage (APR = 1.32, 95% CI: 1.32(1.03, 1.69), and receiving ART for more than 8 years (APR = 1.78, 95% CI: 1.18, 2.67) were found to be independent predictors of FAV dietary intake among HIV-infected adults. From the findings, we understood that farmers were less likely to consume FAVs compared to employed individuals, daily laborers, and merchants. The finding indicated a very low level of FAV dietary intake among HIV-infected adults receiving ART, falling well-below the minimum recommendation for physically active adults. Despite living in areas with surplus production and producing these items, farmers are less likely to consume FAV. The study emphasizes the importance of focusing on the early stage of ART treatment for patients and family therapy, including counseling and guidance on consuming healthy diets such as FAVs, to enhance the role of children as caregivers for their families. Additionally, there is a need for comprehensive nutritional counseling to improve FAV consumption, with a particular emphasis on educating individuals about portion size estimation for the consumption of FAVs.

Economic impact and food security effects of trade disruptions in agricultural products for Sweden

The COVID-19 pandemic and geopolitical conditions in 2022–2023 highlighted the vulnerabilities of food supply chains to trade disruptions in agricultural inputs and foods, with the ensuing economic effects on producers and consumers. This study calculated the impact of various disruptions in the trade of agricultural inputs and outputs for Swedish producers and consumers and for food security. To this end, a mathematical programming model of the food sector with a spatial dimension was applied, which accounts for adjustments and interactions between producers and consumers of food. Food security is measured in terms of the self-sufficiency ratio, the ability to produce minimum dietary needs, and economic access for low-income households. The trade scenarios included disruptions to imports of agricultural inputs (fertilisers, fuel, feed, pesticides and foreign labour) and foods. The results showed that the economic effects for producers can be considerable, with a reduction in producer surplus by up to 75%. The decrease in consumer surplus is smaller, amounting to a maximum decrease of 21%. The self-sufficiency ratio and the ability to produce minimum dietary needs can be reduced by 55% and 61%, respectively, but may rise if the disruption to feed imports increases. Economic access to foods is slightly decreased in all scenarios. These results showing different impacts of trade disruptions on producers and consumers and food security metrics highlight the need to undertake extensive assessments to determine whether and how to prevent and mitigate their effects. The economic effects on producers and consumers and the associated impacts on food security are likely to differ, which affects the selection and targeting of policies, such as compensation for economic losses and promotion of food security.

Evaluation of proposals from key suppliers of small-scale photovoltaic installations for single-family homes considering current regulations and environmental and economic criteria—A case study in Malaga, Spain

The economic viability of a photovoltaic (PV) installation depends on regulations regarding administrative, technical and economic conditions associated with self-consumption and the sale of surplus production. Royal Decree (RD) 244/2019 is the Spanish legislation of reference for this case study, in which we analyse and compare PV installation offers by key suppliers. The proposals are not optimal in RD 244/2019 terms and appear not to fully contemplate power generation losses and seem to shift a representative percentage of consumption to the production period. In our case study of a residential dwelling, the best option corresponds to a 5 kWp installation with surplus sale to the market, with a payback period of 18 years and CO2 emission reductions of 1026 kg/year. Demand-side management offers a potential improvement of 6%–21.8%. Based on the increase in electricity prices since 2020, the best option offers savings of up to €1507.74 and amortization in 4.24 years. Considering costs and savings, sale to the market could be considered as the only feasible regulatory mechanism for managing surpluses, accompanied by measures to facilitate administrative procedures and guarantees for end users.

Cassava Flour as a Possible Replacement for Wheat Flour: A Comprehensive Review Considering the Sri Lankan Scenario

Cassava (Manihot esculenta) is a long tuberous starch-containing root crop that stands as a significant staple food globally. Its adaptability to various climates has increased its commercial growth. However, challenges such as toxic cyanogenic glucosides and rapid perishability in cassava demand its processing for safety and extended shelf-life. In Sri Lanka, where cassava is widely consumed, surplus production can be a highly prospective revenue. This review summarizes the utilization of cassava flour as a potential alternative for wheat flour emphasizing the Sri Lankan scenario. The cassava flour production process involves cleaning, peeling, slicing, drying, grinding, and sieving. Nutritional composition varies among cultivars, with variations in starch, amylase, fiber, protein, and ash. The cyanogenic levels also depend on the cultivars. Cassava flour emerges as a promising wheat flour substitute due to its abundance, effortless cultivation practices, nutritional profile, and unique functional properties. Furthermore, cassava flour is gluten-free and considered as the most comparable gluten-free substitute to wheat flour in terms of texture and taste. The incorporation of cassava flour into bakery products shows an opportunity to reduce the massive dependence on costly wheat flour imports in developing countries, which improves the country’s revenues. This review focuses on diverse food applications of cassava flour, including cookies rackers, biscuits, and commercial products, highlighting cassava flour's market potential in Sri Lanka amidst the increasing demand for gluten-free products.Keywords: Cassava Flour, Wheat Flour, Substitute, Sri Lanka, Food Products

The Impact of CSR Implement Modes on Sustainable Supply Chain Pricing and Green Decision Making

Green transformation is an effective way for supply chains to achieve sustainable development. In the heterogeneous substitute product coexistence environment, it is valuable to explore the motivation behind CSR implementation as well as the advantages and differences associated with different members’ CSR implementations. In this study, we consider that the manufacturer produces both green products and ordinary products that are substitutes for each other and construct a CSR-absence scenario (Model N), a retailer implementing CSR scenario (Model R), and a manufacturer implementing CSR scenario (Model M). Applying a game-theory-based method, we obtain the optimal pricing, green decision, and supply chain profit under different scenarios. We analyze the effects of consumers’ green preference, green product function coefficient, and CSR level on decision making and performance. Through comparison and numerical analysis, we find the following: (1) Although the CSR behaviors of the manufacturer and the retailer squeeze the market demand space of the ordinary products, the greenness of the green product increases, and the retail price decreases. This not only enhances the consumer surplus of green products but also increases the profit and social welfare of the supply chain system. (2) The eco-friendliness of green products, product demand, and social welfare levels are the highest when the retailer implements CSR, followed by when the manufacturer implements CSR, and are the lowest in the CSR-absence scenario. In addition, the following retailer can enhance both its and the manufacturer’s profits through implementing CSR within a reasonable range. (3) The numerical analysis results show that, when the functional attributes of the green products meet a certain level, supply chain members implementing CSR does not affect consumers’ choice of green products.

The impact of green credit guidelines on environmental performance: Firm-level evidence from China

The Green Credit Guidelines (GCG) regulates the environmental behaviour of firms with high pollution, high energy consumption, and surplus production capacity (known as “two high and one surplus”, THOS) through environmental and social risk assessment and credit management, thereby improving firms' environmental performance. Adopting the panel data of 461 Chinese A-share listed firms from 2008 to 2020 and the Difference-in-Differences (DID) model, this paper employs the promulgation of GCG in China as a quasi-natural experiment to investigate the effect of GCG on THOS firms' environmental performance and its potential mechanisms. The main findings are reported as follows. Firstly, the promulgation of GCG significantly improves the THOS firms' environmental performance. Secondly, after dividing the firms' environmental performance into the environmental strengths and concerns, the policy effect is stronger on environmental strengths that focus on process control. Thirdly, the firms' environmental performance improvement effect of the GCG is mainly achieved by promoting green innovation and exacerbating financing constraints. Finally, the improvement effect of the GCG on firms' environmental performance is more pronounced in firms with weaker external monitoring, environmental information disclosure and lower capital dependence.

Glycerol-Free Biodiesel via Catalytic Interesterification: A Pathway to a NetZero Biodiesel Industry

Conventional biodiesel manufacturing uses alcohol as an acyl acceptor, resulting in glycerol as a side product. The increased demand for biodiesel has led to the production of a substantial surplus of glycerol, exceeding the market need. Consequently, glycerol is now being regarded as a byproduct, and in some cases, even as waste. The present study aims to suggest an economically viable and ecologically friendly approach for maintaining the viability of the biodiesel sector. This involves generating an alternative byproduct of higher value, rather than glycerol. Triacetin is produced through the interesterification of triglycerides with methyl acetate, and is a beneficial ingredient to biodiesel, reducing the need for extensive product separation. The primary objective of this research is to improve the interesterification reaction by optimising process parameters to maximise biodiesel production while using sulphuric acid as an economically viable catalyst. The study utilised the Box–Behnken design (BBD) to investigate the influence of various process variables on biodiesel yield, such as reaction time, methyl acetate to oil molar ratio, and catalyst concentration. An optimisation study using Response Surface Methodology (RSM) focused on key process reaction parameters, including the methyl acetate to oil (MA:O) molar ratio, catalyst concentration, and residence time. The best conditions produced a biodiesel blend with a 142% yield at a 12:1 MA:O molar ratio, with 0.1 wt% of catalyst loading within 1.7 h. The established technique is deemed to be undeniably effective, resulting in an efficient biodiesel production process.

Experimental investigation of BIPV/T application in winter season under Şanlıurfa's meteorological conditions

AbstractConsidering that nearly 39% of the total CO2 emission released into the atmosphere today are thought to be due to the energy consumed by buildings, the importance of taking measures through buildings to combat global warming is evident. Therefore, the concept of nearly zero‐energy buildings (NZEB) is come to the forefront. Building integrated photovoltaic thermal (BIPV/T) systems are used to enable buildings to generate their own energy. However, buildings have limited facade and roof areas required for BIPV/T systems. Therefore, in this study, various configurations of bifacial (double‐sided) and monofacial (single‐sided) panels were compared to investigate ways to enhance the efficiency of BIPV/T systems. Different air flow velocities and varying air gap distances were tested for both panel types. By placing a reflective surface on the wall behind the bifacial panel, the electrical efficiency of the bifacial panel was increased and proven through PVsyst analysis. Both panels provided maximum heat efficiency at the shortest air gap distance under high air flow conditions. In addition, it was shown in both the experimental setup and Comsol CFD analysis that it provides significant benefit in the thermal energy load of the building when heating the interior environment in winter. In terms of electrical power production surplus, the bifacial panel outperformed the monofacial panel in all configurations, with a minimum advantage of 8.33% and a maximum of 12.73%. Additionally, the maximum electrical efficiency was obtained from the bifacial panel in configurations with the longest air gap distance. Using the bifacial panel in the BIPV/T system with the shortest air gap distance during the heating season and the longest air gap distance during other seasons can provide the highest efficiency for the building throughout the year.

Antibacterial resistance and the cost of affecting demand: The case of UK antibiotics

Consumption of broad-spectrum antibiotics is associated with rising antimicrobial resistance (AMR) levels. The use of broad-spectrum drugs, particularly of cephalosporins, quinolones, and co-amoxiclav contributes the most to the rise in AMR. We use aggregate sales data on antibiotics from the UK to estimate structural demand models and reveal drug substitution patterns. We then simulate alternative tax schemes to evaluate the effectiveness of shifting demand from broad- to narrow-spectrum drugs. Our estimates suggest that these policies can be highly effective in demand management and come at a relatively low cost regarding changes in consumer and producer surplus.

The Meṣad Ḥashavyahu Ostracon in its Regional, Economic, and Political Context

ABSTRACT This article uses updated models of the 7th-century bce economy to argue that the harvesting activities reported in the Meṣad Ḥashavyahu ostracon occurred at a small grain-cultivating site located in the Judahite highlands. The distance between this farmstead and the inscription’s coastal findspot explains why the ostracon was inscribed in the first place: the harvester could not appeal his case in person. As can be detected in the complaint, the granary complex in the Judahite highlands specialised in cereal products and was conversely not designed for the cultivation of a diversity of crops for local subsistence. This economic choice likely originated in Judah’s effort to contribute its own grain surpluses to a broader regional network of trade and commerce, one which was defined by specialised zones of surplus production that originated in the wake of Sennacherib's campaign in 701 bce. Because Egypt built the fortress in which the inscription was found and moreover coerced Judah's king and people into a new system of obligatory payment (2 Kgs 23:29-35), the ostracon represents a stunning glimpse into a time when Judah’s own administration was forcing its labourers to meet the extractive demands of an external power. The commander (śar) in the fortress was the logical authority for the harvester’s case, as (1) a high-ranking figure close to both the Egyptian and Judahite powers, (2) a recipient of inland grain products, and (3) a potential keeper of important transactional documents.

Novel curled cooler to enhance the efficiency of a photovoltaic panel system

The overheating of photovoltaic panels can result in decreased efficiency, potential long-term damage, and reduced energy production. This study proposes a passive cooling system with a new curled aluminum fin profile to mitigate these issues. The thermal response of solar panels with variations in the geometrical parameters of the new curled fin design was studied using computational fluid dynamics (CFD) simulations, where the best-curled fin design option was selected for its implementation. Experimental tests were conducted to determine the thermal-energy response in a PV panel with the new design, compared with a rectangular fin design and without a cooling system as a reference. An economic analysis was also conducted to quantify the payback time based on the energy cost and surplus production rate. The experimental results showed that the new proposed system reduces the panel temperature to 8 °C, knowing that the no-fins system increases the PV panel temperature to 16 °C above ambient. Additionally, the energy production was increased by 4 % with the proposed curled fins, and the payback time varied between 1.1 to 6.4 years, depending on the kWh energy cost per country.

О равновесных ценах и законах спроса и предложения

As a result of the equalization of the profitability of capitals (which is associated with the formation of a surplus of commodities and production), with the constancy of the volume of circulating money (which maintains the constancy of the price level), as a result of the selective inclusion of consumption requests in the market, in a certain interval of the ratio of satisfied demand to total supply, there is observed, due to a number of reasons that prevent the reduction of prices, the stabilization of the prices of final commodities in relation to their value, their maintenance in equilibrium even with some redistribution of satisfied demand between goods. Continuing the logic of marginalism, we must conclude that the partial marginal utilities of less rare commodities, through the limitation of their consumption, are necessarily equated with the marginal utility of the rarer commodity, which has unaccounted consequences. The «laws of supply and demand» (where price is not defined as a concept [1, p.24]) are incompatible with the theory of marginal utility, which means that price is a function of the amount of consumption, but not vice versa. The law of demand, in essence, asserts the tendency of the partial rarity of a commodity, due to the growth of purchases, to its market rarity without observing marginal ratios. The assertion that when the price rises, it is advantageous to increase production, is inconsistent with the marginal position that the price rises with an increase in the scarcity of the commodity, which corresponds to a decrease in the amount of utilities that go into income. The dependence of demand on price is consistent with the labor theory of value.

Social and Seasonal Organisation of Red Deer Hunting from the Neolithic to the Late Iron Age (c. 2000 BC to AD 1000)

This is the first paper to examine social and seasonal organization of red deer hunting using stone-set hunting blinds in Norway. The paper examines seven hunting blinds discovered in Gjesdal, western Norway. Four of the hunting blinds are unique; it was possible to date them directly with radiocarbon dating. The sites exhibit multiple construction phases, with a usage period ranging from the Neolithic to the Mid Iron Age, and we would suggest likely extending into the Late Iron Age and Middle Ages. The datings and multiple phases make it possible to discuss temporal change in the construction of the hunting blinds, which is unprecedented in a Fennoscandian context. Hunting appears to align with social trends, becoming more prominent during periods of settlement decline and increased use of outfield resources for surplus production. While hunting in the lowlands of western Norway, particularly between 0 and 900 metres above sea level, appears to have been smaller in scale compared to mass-scale hunting in Norway’s high-altitude zones and eastern regions, the high population of red deer until about 500 years ago indicates profitable hunting opportunities during specific seasons. The cluster of hunting blinds suggests organized cooperation among neighbours and families, with surplus products potentially sold and exported to local and regional markets.

POSTHARVEST EVOLUTION OF PECTINOLYTIC ERWINIA AND ERWINIA SOFT ROT DURING COLD STORAGE OF CONSUMPTION POTATOES PRODUCED IN ALGERIA

In Algeria, potatoes ranks second among the twenty main food crops. It’s characterized by periods of overproduction corresponding to seasonal crops. Except these periods, supply tends to fall. In order for the availability of potatoes to be constant throughout the non-harvest periods, it is imperative to store the surplus production to ensure a constant supply during periods of unavailability of a new harvest. The storage of the potato must maintain a satisfactory quality and minimize losses and the postharvest development of bacteria and fungi. This work aims to identify and follow the evolution of pectinolytic Erwinia and Erwinia soft rot during storage at 4 and 10° C of two varieties of potato grown in Algeria, i.e. Spunta and Désirée. The results indicated the presence of three species of Erwinia: E. carotovora subsp. carotovora, E. carotovora subsp. atroseptica and E. chrysanthemi. Initially, for both varieties, E. carotovora subsp. carotovora predominates followed by E. carotovora subsp. atroseptica and finally E. chrysanthemi. During storage, the three species evolve almost in the same way and their multiplication is more important at 10° C than at 4° C, particularly on the Spunta. About the total bacteria, the highest levels are recorded on Spunta, especially at 10° C. In addition, the Erwinia spp. / total bacteria ratio showed that Erwinia spp. are very most abundant compared to the total bacteria. The assessment of soft rot losses has also shown that they are greater in the Spunta variety whether at 4 or 10° C.

Synergies and competition: Examining flexibility options in the European electricity market

The electricity market transitions from a market clearing in which flexible generation meets inflexible demand to one in which inflexible generation meets flexible demand. Consequently, new types of flexibility are needed to balance generation and demand. This paper mainly aims to analyse competition and synergy between various flexibility options in the electricity market. The developed European electricity market model maximises the joint socio-economic welfare of the electricity and the hydrogen market. Transmission grid,- storage expansion, electric vehicle demand side flexibility and hydrogen sector coupling are flexibility options. This work examines the implementation of different flexibility options in the bidding zones Austria and Germany. Austria, with a very high storage capacity in the alpine arc and Germany, with massive wind turbine capacities serve as representative case study. Results show that the storage location heavily influences the corresponding socio-economic welfare increase. Hence, location-dependent synergy and competition between storage and transmission line expansion can occur. In contrast, sector coupled hydrogen production and storage expansion compete with each other as both will reduce very low electricity prices. Demand-side flexibility primarily benefits end-users while producer surplus reduces. In combination with storage expansion, further positive synergistic effects for end-users occur. The combination of storage expansion and demand-side flexibility can replace transmission line expansion and vice versa if used comprehensively. Further efforts could address the evaluation of these effects if the individual flexibility providers aim for something other than a system-wide but individual optimum.

Capitalist, Evolution, Financial Innovations and Financial Literacy: A Study of their Dynamics in Shaping Modern Capitalism

Finance has had its root in human history since human being started a settled civilized life. As production for trade took a shape, various means of transactions and storage of value kept on evolving. Gradually, finance took the center stage with the evolution of modern capitalism. In early stages the financial instruments remained a scattered individual means of financial practice, no central regulation existed in the early era. Hence the acquaintance with these instruments was also confined to individual users, the traders, particularly. Since economic productivity was quite low, ordinary individuals had little surplus to save, not many had much to do with financial literacy. The modern capitalism required industrial workers, surplus of agricultural products, more consumers for market, more means of production to produce trade surplus and more financial savings and instruments to channelize investments. Also the producers were required to be alienated from the product of labour so that the trade of commodities could be taken in control by the trading class. Also the means of production, which was otherwise the ownership of the households, was to be turned marketable to facilitate the transfer the ownership from ordinary owners to the trading class. The trinity of commodity production, wage labour and market system altogether had to evolve for capitalism to come into existence. Accordingly, various financial instruments took shape, the traditional ones became more formalized and many new ones were invented. The evolution of different forms of business, the 'company' form particularly, helped this process in a big way. Simultaneously, the financial anarchy put the systems in turmoil and hence regulatory bodies became a compulsion. These regulatory bodies assumed the twin role of regulation of financial markets, financial facilitation, as well as creating financial literacy among ordinary people to link their savings to the mainstream trade and commerce lines. The paper attempts to portray the evolution of modern financial system and find out how this evolution has been linked to the financial literacy of the common masses. Also the paper would throw lights on imminent market and systemic hazards caused by excess leliance on financialisation of economic system.

Effects of time-of-use pricing for residential customers and wholesale market consequences in South Korea

Using a large-scale pilot test on time-of-use (TOU) pricing for residential customers, this study analyzes the effects of TOU pricing on the load patterns of residential customers and on producer surplus in South Korea. We estimate the difference in the electricity demand functions of residential customers across peak, intermediate, and off-peak periods before and after TOU pricing. In addition, we assess the supply curve in the wholesale electricity market and calculate the changes in electricity purchase costs by integrating the supply curve over the range of consumption changes across the periods. This study simulates the effects of TOU pricing on producer surplus that would be obtained if all residential customers in South Korea switch from increasing block pricing to TOU pricing. Our results show that TOU pricing can be an effective measure for load transfer and simultaneously increase producer surplus. We find that although the revenue of electric utility generally decreases, the cost savings are greater and thus producer surplus increases. The results can be a valuable reference for the South Korean government regarding the nationwide expansion of TOU for residential electricity in the future.

Good practices for surplus production models

Surplus production models (SPMs) have a long history in fisheries ecology and are important for the assessment and management of marine species and stocks. However, the implementation, application, and usage of these models vary across regions and case studies. Good practice guidelines can streamline modelling workflows, inform the acceptance or rejection of an assessment, and facilitate the derivation of management advice from accepted assessments. This paper discusses current practices in the application of SPMs and proposes good practice guidelines for their use in stock assessment. We complement our recommendations with results from a simulation study examining the performance of an age-based operating model and a SPM assessment model under 60 scenarios with various assumptions regarding data quantity, quality, and model priors. We provide specific good practice guidelines for two widely used state-space SPMs: SPiCT and JABBA. Finally, we discuss current limitations and suggest avenues for future developments for SPMs.

Gross ecosystem product accounting in Miyun County: the supply and use of ecosystem services

The ability of an ecosystem to provide services differs from its actual consumption and use by human society. Overuse of ecosystems can degrade ecosystems. In order to evaluate the supply capacity and use status of the ecosystem in Miyun County, so as to better apply the ecosystem services to different policies and management, the supply and use of 10 types of ecosystem services in Miyun County were calculated by using value indicators, namely potential gross ecosystem product (GEP) and actual gross ecosystem product. The results show that: (1) In 2020, potential gross ecosystem product of Miyun County is 254.32 billion yuan, and actual gross ecosystem product is 53.28 billion yuan, accounting for 21% of the potential gross ecosystem product. (2) Among all kinds of ecosystem services, the contribution of water conservation services in potential gross ecosystem product is the highest, and the contribution of climate regulation services in actual gross ecosystem product is the highest. (3) The contribution of wetland was the highest in potential gross ecosystem product, while the contribution of forest was the highest in actual gross ecosystem product. (4) Natural ecosystem area and vegetation coverage are the main factors affecting potential gross ecosystem product, while actual gross ecosystem product is mainly affected by GDP and population. (5) By studying the potential supply and actual use of ecosystem services, we evaluated and distinguished between the services that ecosystem could produce and the services that were actually used by humans, and compared the supply capacity and actual use to assess the sustainability of ecosystem services, in order to formulate different policies and management measures for gross ecosystem product surplus and deficit regions. Potential gross ecosystem product could provide data support for the assessment of ecological protection benefits. Actual gross ecosystem product could be included in the system of national accounts, and as a standard for ecological compensation and ecological trading. Confusing potential supply and actual use in policy application would affect the effect of policy implementation, and distinguishing them could ensure policy implementation. The relative size of the relationship between the two could reflect the present and future levels of human well-being in a region. Both together provided management basis and policy-making support for guiding regional ecological protection and sustainable development.

POTENTIAL AND LEVEL UTILIZATION OF SKIPJACK (Katsuwonus pelamis) IN THE BUNGUS OCEAN FISHING PORT WEST SUMATERA PROVINCE

The skipjack (Katsuwonus pelamis) in Bungus Ocean Fishing Port has been evaluated for its sustainable potential using the surplus production approach method. The findings indicate a strong alignment with the Fox approach model. The estimated sustainable potential for skipjack is 471 tonnes per year, with an ideal effort of 45 trips annually. The analysis indicates a moderate utilization status, with an average skipjack utilization rate of 62.76%. It is evident that around 37.24% of its maximum sustainable potential, equivalent to 154.74 tonnes per year, is still unexplored. In addition, the catch rate of skipjack is relatively high at 96.14%, indicating that there is still some untapped potential, with 3.86% of the optimal fishing effort or two trips per year remaining unused. As a result, it is recommended that a total allowable catch of 341 tons be set in order to ensure the long-term sustainability of skipjack harvesting in the area.