Competitive trends of Atlantic bluefin tuna farming among major Mediterranean producers, with special emphasis on human capacity by population growth

MARINE REPORTS, 4(2) 2025 : 130-138 DOI: 10.5281/zenodo.17477669 [email protected] MARINE REPORTS e-ISSN: 2822-5155 Journal homepage: https://scopesscience.com/index.php/marep/ Received: 20 October 2025; Received in revised form: 29 October 2025 Accepted: 29 October 2025; Available online: 21 December 2025 RESEARCH PAPER Citation: Yigit, Ü. (2025). Competitive trends of Atlantic bluefin tuna farming among major Mediterranean producers, with special emphasis on human capacity by population growth. Marine Reports, 4(2), 130-138. https://doi.org/10.5281/zenodo.17477669 COMPETITIVE TRENDS OF ATLANTIC BLUEFIN TUNA FARMING AMONG MAJOR MEDITERRANEAN PRODUCERS, WITH SPECIAL EMPHASIS ON HUMAN CAPACITY BY POPULATION GROWTH Ümüt YIGIT* * Underwater Technology Program, School of Maritime, Çanakkale Onsekiz Mart University, Dardanos Campus, Çanakkale 17020, Türkiye Ümüt Yigit: [email protected], https://orcid.org/0000-0002-1378-2422 * Corresponding author: Ümüt YIGIT, [email protected], +90-549-5350122 Abstract This study aims to investigate the economic dynamics among five major tuna producing countries in the Mediterranean: Malta, Spain, Türkiye, Croatia and Tunisia which provide significant amounts of tuna for the growing demand in the market network. Major drivers of the tuna farming were identified based on annual production yields provided by FAO statistics. The growth trends and economic development of the tuna production industries in the three key producers of tuna have been evaluated and superimposed with the increasing trends in population densities between 2006 and 2023. Tuna harvests from farms in Malta increased around 3-fold from 6,069 to 18,623.7 tons between in 2006-2023, while in Spain approximately 4-fold increase was noted in the last 18 years, from 2,572 to 10,652.8 tons. Among the five major producers in the Mediterranean, Türkiye increased its harvest by 9.4-fold between the same years, reaching 3,674 tons in 2023 from the relatively low level of 390 tons in 2006. Tunisian production increased by 3.2-fold from 450 to 1,439 tons between 2006-2023, whereas Croatian tuna farming declined by 0.49-fold from 6,700 to 3,242 tons over the past 18 years. In terms of economic gain, tuna producers of Malta achieved around 9% higher economic gain than Spain, and around 72, 83, and 94% higher economic efficiency than Croatia, Türkiye, and Tunisia, respectively. Considering the importance of skilled labor in production, the relationship between harvest volumes and population growth by country was examined through correlation. Strong correlation between production and population growth was observed in both Malta and Türkiye over the 18-year period (R=0.91, Malta; R=0.90, Turkey), whereas no such strong correlation was found in Spain (R=0.68), followed by Tunisia (R=0.49) and Croatia Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 131 (R=0.14) for the same years of investigation. The results of this study highlight the importance of manpower in the production and operational processes of the aquaculture industry, in addition to other factors. Furthermore, considering the need for more comprehensive studies on human capacity in aquaculture, findings of the present study shed light and encourage future research. Keywords: Bluefin tuna, export, manpower, Mediterranean aquaculture, population growth Introduction For the global food security, marine cage aquaculture industry plays an important role with remarkable economic inputs for Mediterranean countries. While the economic dynamics of aquaculture depend on many factors, infrastructure, marketing networks, and human resources are important drivers for successful farm operations. Investments in infrastructure and human resources, in particular, may increase production efficiency over time, contributing significantly to business profits and economic growth (Hishamunda et al., 2009). Further, planning and management of production systems in aquaculture operations also depends on long lasting practices and are linked to skilled human resources and the availability of finance for beneficial outcomes (Verdegem et al., 2023). The shortage of manpower has been reported as one of the most significant challenges facing aquaculture producers (Engle et al., 2019; van Senten & Engle, 2017; van Senten et al., 2020a, b). Declines in trained human resources and manpower during the recent pandemic of Covid-19, for example, disrupted production processes, that in turn reduced yields and further result in food shortages. Lockdowns and border closures as measures for epidemic spreads, caused severe consequences for the supply chain of the food business (Maqbool et al., 2024). Dolgui et al. (2020) and Mahmood et al. (2022) underlined that the pandemic outbreak disrupted the global supply chain with goods shortages due to shipping delays, and increased transportation costs. Interruptions in logistics resulted in decline of manpower that further caused delays in good transportation, which broke the network of trade continuity and export distribution. Atlantic bluefin tuna (Thunnus thynnus), the most important tuna species in Mediterranean tuna farming industry, has a remarkable high value in the global fish trade market, making it a major contributor to Mediterranean Economy (Jelic Mrcelic et al., 2023). Therefore, any disruption in the production yields of tuna harvest, either due to manpower shortage, trade restrictions or price fluctuations may have severe impacts on economic indicators. The present study aims to evaluate competitive economic trends of Mediterranean tuna aquaculture among the major producers of Malta, Spain and Türkiye, with a special reference to production quantity and economic value in the trade network with super-imposure of human population growth, a major driver to the availability of manpower. Through evaluation of several parameters, this study provides understanding of the vulnerability and resilience of the tuna cage farming industry under severe conditions during periods of crisis. The results of this study may help farm managers and policy makers to improve the strength of the supply chain resilience, contribute to future challenges and sustainability of tuna farming in the Mediterranean region. Material and Method Data collection and analyses Production quantity for the Atlantic Bluefin tuna was back dated 16 years of market value and harvest yields from 2006 to 2023, and data collected using statistical query panels provided by Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 132 Food and Agricultural Organization. (2025a, b). Variables measured in the present study are provided as means ± SD. The growth trend of production yields over 16-years has been formulated following the equation provided earlier (Yigit & Kusku, 2022; Yigit et al., 2023); 𝐻𝐺=(𝐹𝐻−𝐼𝐻) 𝐼𝐻 )𝑥)100 where, HG: harvest growth of tuna in tons FH: final year of tuna harvest in tons IH: initial year of tuna harvest in tons Sales price per unit for each export country has been calculated by dividing the production value by quantity following the equation of Yigit et al. (2023): 𝑆𝑃𝑢=𝑝𝑣 𝑝𝑞 where, SPu: unit sales price pv: production value in $US pq: production quantity in tons Relative population growth was calculated using the following equation (Yigit et al., 2023): 𝑅𝑃𝐺=(𝑓𝑖𝑛𝑃−𝑖𝑛𝑖𝑃) 𝑖𝑛𝑖𝑃 )𝑥)100 where, RPG: relative population growth iniP: initial population finP: final population Statistical analyses The correlation between the growth of population and increase of yields have been evaluated by using MacBook Pro, macOS Big Sur (11.7.3), running a Microsoft Excel program for Mac, based on the following formulae: 𝐶𝑜𝑟𝑟𝑒𝑙)(𝑥,𝑦)=∑?𝑥− ` 𝑥@?𝑦− ` 𝑦@ A)∑?𝑥− ` 𝑥@!)∑)?𝑦− ` 𝑦@! where,`x and`y indicates the sample means for two different series, that was set as growth in tuna production in countries for Serie 1, and human population growth in countries for Serie 2. Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 133 Results and Discussion Tuna farming constitutes an important fisheries industry in the Mediterranean and, with its continuous development and new investments, supports new employment opportunities (Miyake et al., 2003). With its high commercial interest, the Atlantic bluefin tuna (Thunnus thynnus) supports economic development of countries bordering the Mediterranean, via capture-based fattening aquaculture operations (Ottolenghi, 2008). The production of Atlantic Bluefin tuna in the Mediterranean has been steadily growing over the last decade and reached a peak level of 37,864.34 tons in 2023 (Food and Agricultural Organization, 2025c). While scientific research on tuna generally focuses on its biology and population dynamics, studies on the economic evaluation of tuna farming are quite limited (Bjørndal, 2023). Five major producers of Atlantic bluefin tuna in the Mediterranean, identified by the annual production reports of FAO statistics (Food and Agricultural Organization, 2025a). Malta, Spain, Türkiye, Croatia and Tunisia, providing a significant amount of tuna for the growing demand in the market network, were evaluated in terms of their production performance and competitive economic trends. The present study investigates the growth and economic developments over the last 18 years because Malta, one of the largest tuna producers in the Mediterranean area, began tuna farming in 2006. Particular attention was paid to ensuring that data analysis was conducted over the same time-frame across all countries covered in the study. Therefore, the study focuses on growth and economic developments between 2006 and 2023. Based on data evaluation in this study, Malta gave a first record of Atlantic bluefin tuna harvest with 6,069 tons in 2006 and reached 18,623.7 tons in 2023. Over the last 18 years, Malta provided a total harvest yield of 170,394.41 tons with around 3.07-fold growth from 2006 to 2023. Spanish production hit a peak of 13,145.3 tons in 2022, with a total production of 97,063.9 tons for the same time-span, that was around 4.14-fold increase from 2,572 to 10,652.8 tons in the last 18 years. Türkiye provided a total of 37,648 tons with around 9.42-fold growth from 390 tons to 3,674 tons between 2006-2023. Tunisia demonstrated a 3.2-fold production increase from 450 tons in 2006 to 1439 tons in 2023. Even though the total production yield (60,896.50 tons) of Croatian tuna farming over the past 18 years ranked third among the main producers, its production growth showed a 0.49-fold decline from 6700 tons in 2006 to 3242 tons in 2023. According to the latest statistical information (Food and Agricultural Organization, 2025a), Malta alone supplied nearly half (49.19%) of the total Mediterranean Atlantic bluefin tuna production, whereas Spain produced 28.13 %, Türkiye 9.7 %, Croatia 8.59%, and Tunisia 3.8% of the total production delivered to international markets from marine cage farming sites in the Mediterranean area (Figure 1). In comparison of the economic gain among the main producers of the Mediterranean tuna farming industry, Malta demonstrated approximately 9%, 72%, 83%, and 94% greater economic income compared to Spain, Croatia, Türkiye, and Tunisia, respectively (Figure 2). When evaluating the relationship through correlation between harvest volumes and population growth by country, in consideration of the importance of skilled human capacity in fish farms, a relatively strong correlation was assessed between production and population growth of both Malta (R=0.91) and Türkiye (R=0.90) over the past 18-years span, compared to Spain (R=0.68) and Tunisia (R=0.49), where no such strong correlation was found. The correlation between production and population growth for Croatia however was remarkably low (R=0.14), in comparison to the other main producers in the Mediterranean (Table 1). Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 134 Despite the fact that the highest production of Atlantic bluefin tuna was recorded in Malta (170,394.41 tons) between 2006-2023, the percent production increase was highest (842.05%) for the Turkish tuna production, followed by Spain (314.19%), Tunisia (219.78%), and Malta (206.87%). Percent production increase of Croatia, however declined by 51,46% over the past 18 years (Table 1). Figure 1. Production trend of Atlantic bluefin tuna in the Mediterranean (top five producers, 2006-2023) (produced based on data provided by the Food and Agricultural Organization, 2025a). Figure 2. Production value of Atlantic bluefin tuna in the Mediterranean (top five producers, 2006-2023) (produced based on data provided by the Food and Agricultural Organization, 2025b). Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 135 Table 1. Total Atlantic bluefin tuna production, production growth in percent, and correlation between production growth (PG) and population increase (PI) in the top-five Mediterranean producers over the past 18 years from 2006 to 2023. Country Malta Spain Croatia Türkiye Tunisia Variables PG* PI** PG* PI** PG* PI** PG* PI** PG* PI** Year 2006 6069 415454 2572 44695448 6700 4315800 390 70045349 450 10346410 2007 6813 417197 4076 45516507 4180 4315954 870 70750586 511 10441702 2008 5039 418969 3216.7 46235054 3711 4314631 710 71562338 611 10542635 2009 3441 420795 2378.6 46635180 4200 4310530 910 72464848 380 10650681 2010 4955 422651 1793.4 46840471 3368 4301145 580 73346769 373 10765980 2011 1759 424628 2866 46998043 3368 4280824 100 74215203 350 10886035 2012 3904 426611 2987.7 47018323 1906.7 4259236 395 75197198 841 11009642 2013 6123 428452 2902.6 46860389 2616.3 4242398 470 76403031 380 11141361 2014 5451 434485 3088.4 46720188 2223.8 4219479 1136 78036154 479 11274288 2015 8051 444981 4690.7 46683686 2603.4 4183729 1710 80014226 199 11402264 2016 11292 455269 4562.3 46732771 2934.3 4136444 3834 81652088 218 11528674 2017 13120 467902 5136.1 46868596 2161.6 4079200 3802 83083662 0 11650498 2018 17326 484558 7574.6 47092821 3227.1 4024868 3571 84415969 0 11765514 2019 11970 504015 8107.8 47435119 2746.7 3986334 2327 85357672 1310 11875081 2020 17093 518207 8913.4 47679489 3323 3953958 4338 86091692 1194 11974057 2021 13548.8 524376 8399.5 47735664 5103.9 3924610 4952 86686253 1318 12048622 2022 15815.9 528192 13145.3 47828382 3270.7 3907027 3879 87058473 997 12119334 2023 18623.7 532956 10652.8 47911579 3252 3896023 3674 87270501 1439 12200431 ∑-TP 170,394.41 97,063.90 60,896.50 37,648.00 11,050.00 RGR 206.87 314.19 -51.46 842.05 219.78 GFI 3.07 4.14 0.49 9.42 3.20 Correlation 0.907959 0.681484 0.136632 0.897047 0.490741 RGR: relative growth rate (percent production growth), 2006-2023 GFI: growth as fold-increase, 2006-2023 Correlation between production growth (PG) and population increase (PI), 2006-2023 ∑-P: Total tuna production (2006-2023) * PG: Food and Agricultural Organization (2025a) ** PI: Worldometer (2025a-e) While many factors, such as infrastructure and marketing networks, play a role in the economic gains of aquaculture, human resources are particularly crucial for the success of production activities. Therefore, investments in human resources, as well as investments in infrastructure, may increase production efficiency and significantly contribute to the return on investment, thus driving the economic growth of the enterprise (Hishamunda et al., 2009). Despite the fact that long-term operational plans are necessary for successful business management in aquaculture facilities, qualified human resources, as well as the presence of financial resources, play an important role in achieving productive and efficient business goals (Verdegem et al., 2023). Earlier investigations highlight that one of the biggest problems in aquaculture enterprises is the shortage and continuity of manpower (Engle et al., 2019; van Senten & Engle, 2017; van Senten et al., 2020a, b). For instance, during the Covid-19 pandemic, one of the Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 136 largest epidemics Humanity has faced in recent times, countries restricted border crossings to prevent the spread of the epidemic, and even lockdowns resulted in a decrease of workforce, resulting in shortage of skilled human resources, that in turn affected the production process. Consequently, production efficiency decreased, leading to food shortages in many countries. Quarantines and border closures implemented as part of measures to combat the spread of the epidemic significantly affected the supply chain of food businesses (Maqbool et al., 2024), underlining the importance of human capacity and skilled manpower in food production, including aquaculture business. Further, delays in the transportation during the pandemic led to shortages in goods. The severe decline in manpower and human resources also affected the entire process, lead to increase production cost, transportation costs, that in turn created disruptions in the global supply chain (Dolgui et al., 2020; Mahmood et al., 2022). Obviously, earlier reports especially those evaluating the lockdown periods during pandemics, underlined the importance of human capacity in the entire food industry, including logistics, trade network linkage, export chain etc., that eventually highlights the close relation of manpower and the continuity of the food industry. The aquaculture sector is crucial for meeting the food demand of the ever-growing world population, that is expected to reach around 9 billion in the next 20 years, and nearly 10 billion in year 2050, from its current 8.2 billion (Worldometer, 2025f). Aquaculture production worldwide reached 130.9 million tons, accounting for 51% of total aquatic production, that is expected to reach 205 million tons by 2032. The fisheries and aquaculture sector constitutes a significant source of income in the effort to meet the world's growing food demand. While the number of people employed in the fisheries and aquaculture industry, the primary sector of food production, was 62.8 million in 2020, this number decreased to approximately 61.8 million people in 2022 over the challenging times of pandemics. The proportional distribution of total employment in primary production was determined as 54% in fishing, 36% in aquaculture and 10% in other food sectors (Food and Agricultural Organization, 2024). As an outcome from these reports, it can be noted that the aquaculture industry will clearly have a greater responsibility in meeting the increasing food demand as the world's population grows, and issues such as employment and the availability of qualified personnel will become increasingly important. Therefore, while the growth of the aquaculture sector depends on many factors, such as finance, investment, technological advancements, it appears that the importance of the human factor will be increasingly discussed in the very near future. Conclusion Based on the correlation between tuna production growth with population increase on country basis, it can be predicted that a shortage of human capacity may constrain the sectoral development in countries with weak correlation of production growth versus population increase, such as the case in Spain (R= 0.68), Tunisia (R= 0.49), and Croatia (R= 0.14). In contrast however, population growth is compatible with production increase in Malta (R= 0.91) and Türkiye (R= 0.90), indicating that these two countries may have a wider availability of manpower with higher human capacity linkage to correlative population increase, with promising indication of the sustainable growth of farm activities and the future of the Mediterranean tuna aquaculture industry. The results in the present investigation highlight the importance of manpower in both production and operational processes of the food production activities such as the aquaculture industry, in addition to several other factors. Furthermore, considering the need for more comprehensive studies on human capacity in aquaculture, findings of the present study highlights and encourage future research. Yigit. Production and human resources in Mediterranean Tuna farming Marine Reports 4(2) (2025) 130-138 137 Ethical approval Not applicable as no humans or animals were involving in this study. Informed consent Not available as single author is present in this study. Data availability statement The author declares that data can be provided by corresponding author upon reasonable request. Conflicts of interest There is no conflict of interests for publishing this study. Funding organizations No funding available for this study. Contribution of authors Ümüt Yigit: Conceptualization, methodology, resources, data curation, analysis, writing original draft, finalizing paper. References Bjørndal, T. (2023). The Northeast Atlantic and Mediterranean bluefin tuna fishery: Back from the brink. Marine Policy, 157, 105848. https://doi.org/10.1016/j.marpol.2023.105848 Dolgui, A., Ivanov, D., & Rozhkov, M. (2020). Does the ripple effect influence the bullwhip effect? An integrated analysis of structural and operational dynamics in the supply chain. International Journal of Production Research, 58(5), 1285-1301. Engle, C. R., van Senten, J., & Fornshell, G. (2019). 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