Abstract
The carbon footprint (CF) of animal production systems can be estimated by their standings against global protein demand. Türkiye is the largest producer of rainbow trout in Europe, but there is little data on its CF. This study aimed to evaluate the CF expended of concrete pond rainbow trout (CPRT) farming. The data were obtained from a farm with an annual project production capacity of 350 tonnes (APC) over a three-year production (TYP) with different harvest amounts. The total CF expended was the summation of CF expended on compound diets, general management, transportation and machinery, equipment, and construction. The total CF expended was calculated at 1.78 and 1.67 kg CO2e on average for TYP and APC, respectively. The TYP average values of CF expended per kg of protein deposited in harvested/fresh weight fish and CF expended per Mcal of cultural energy expended during production were 10.66 and 0.36 kg CO2e, respectively. The CF expended per 100 kcal food energy in harvested fish was calculated at 0.1263 and 0.1173 kg CO2e on average for TYP and APC, respectively. Aquafeed production and transportation are the important CF expended sources in CPRT. Future studies must be species-specific and culture-specific.
HIGHLIGHTS
The carbon footprint (CF) expended analysis of aquaculture is a reliable criterion for determining sustainability.
Concrete pond rainbow trout farming generates over 80% of the CF for aquafeed and aquafeed transportation.
The CF of the harvested rainbow trout for kg protein and calorie production was lower than that of farm animals.
CF budget calculations should be standardized and made clearer for evaluations.
Graphical Abstract
INTRODUCTION
The increase in the world population, which is expected to reach 10 billion by 2050, and the economic growth of developing countries will increase the demand for animal-derived protein such as meat, milk, and fish (Wu et al. 2014; NRC 2015). Global fisheries production, which has turned into an aquaculture-based food sector since 2013 (FAO 2022), is a qualified protein and fat source to meet the food demand in the face of the increasing world population. It is estimated that the thriving aquaculture sector will produce 62% of food fish by 2030 (TheWorldBank 2013). The sustainability of needs and demands for animal products should be supported by research on food safety (NRC 2015). As a reflection of increasing industrialization and developing technology, with the unplanned use of world resources, aquaculture has turned into an intensive production model aiming to obtain higher productivity per unit area, especially in countries with high industrial levels, in the face of increases in input costs. Especially, the production of carnivore finfish species is also included in these models. Türkiye, which makes a production based on these models, is an industrially important country in carnivorous finfish farming in the world and the Mediterranean Basin (FAO 2022). World production of rainbow trout (Oncorhynchus mykiss) from these species reached 916,540 tonnes in 2019 (FAO 2022). Türkiye, on the other hand, is the second country in world production after Iran, with 144,182 tonnes of rainbow trout production in 2020, and is the leading country in Europe and the Mediterranean Basin (GDFA 2021; FAO 2022).
The biggest source of climate change is greenhouse gas (GHG) emissions from anthropogenic fossil fuels, mostly from energy, industry, transportation, agriculture, and land use sectors (Shahid & Behnassi 2014; UN 2021; Islam et al. 2022a). The greenhouse effect of CO2, which is one of the GHG emission sources, is 25% and its average residence time is approximately 100 years (Eggleton 2018). The carbon footprint (CF), an evaluation criterion in monitoring the effects of climate change, is calculated as CO2equivalents (CO2e) per product (Alley et al. 2007; Weidema et al. 2008; Liu et al. 2016). For this reason, the sum of potential climate effects due to potential climate impact or global warming potential, GHG emission differences in food production systems and the amount of protein in the product, and global warming potential differences of GHG is considered a CO2e measurement unit (ISO 2006a, 2006b; Shahid & Behnassi 2014; Liu et al. 2016; Weidema et al. 2008; IPCC 2022; Jones et al. 2022).
Seventy-seven per cent of the agricultural lands with a habitable land of 48 million km2 of agriculture are livestock (meat and dairy) and 23% of agricultural lands are crops (excluding feed) agricultural land. The global protein support of these lands is 37% for meat and dairy and 63% for plant-based food (Ritchie & Roser 2019). As in all industries, the determination of strategies to reduce crop and crop-based GHG emissions and increase crop yields of the agricultural sector, and water management models that contribute to global warming potential on the basis of CO2e, will make significant contributions to global climate change (Cheng et al. 2022; Islam et al. 2022a, 2022b). The share of livestock production with an annual CO2e value of 8.1 Giga tonnes in total anthropogenic emissions is at the level of 14.5% (Gerber et al. 2013). In addition, if the transition from traditional diets to global diets based on industrial products is not controlled by 2050, an estimated 80% increase in world agricultural GHG emissions from food production and global land use is assumed (Tilman & Clark 2014).
Of the fisheries and aquaculture sources with low GHG emissions, aquaculture has a lower CF than beef and pork and similar to that of poultry (Cochrane et al. 2009; Sonesson et al. 2010; Boyd et al. 2020; Raul et al. 2020; D'Abramo 2021; Table 1). Low CF aquaculture is a potential production area in terms of each of the economic, social, and environmental sustainability principles that need to be addressed at a local, regional, and international scale, and CF values are at a level that can further be improved (Cochrane et al. 2009; Henriksson et al. 2013; Angel et al. 2019; Boyd et al. 2020). Aquaculture, which has an important potential to feed the world population, is included in the sustainable bioeconomy (Boyd et al. 2020). The strategic goal in food production should be based on the principles of sustainability and circular economy (Boyd et al. 2020; Hamam et al. 2021; Tacon et al. 2022; Viles et al. 2022). However, the potential stress effect of climate change can also have an impact on food security and nutrition, as the vulnerability of the system can be increased or decreased depending on vulnerabilities (Gitz et al. 2016). CF analysis can be considered as an approach within the scope of this purpose (Henriksson et al. 2017; Boyd et al. 2020; Rossi et al. 2021; Diken et al. 2022). For this purpose, in order to provide standardization in the CF assessments used in determining the potential situation of aquaculture in sustainability and climate change, kg CO2 emission value per kg of the edible product obtained as a result of all activities should be calculated (Lutz 2021; Diken et al. 2022). In carrying out these studies, empirical studies from the feed and producer sectors are needed, especially in order to calculate aquaculture emissions (MacLeod et al. 2020).
Average daily dietary energy need per | References | ||||
2,373 kcal for 1969–1971 and 2,950 kcal for 2020 | Alexandratos & Bruinsma (2012) and FAO (2021) | ||||
3,025 kcal for forecast 2030 | OECD/FAO (2021) | ||||
Total climate change values of aquaculture (CO2e) | References | ||||
291.2 megaton (Mt) for 2008, 385 Mt for 2010 and 674.6 Mt for forecast 2030 | Hall et al. (2011) | ||||
245 Mt for 2017, 93% of which is calculated, and a forecast 263 Mt with the remaining 7% the share of aquaculture species in total emissions is about 0.49% (263 Mt/53.5 Gt) | MacLeod et al. (2020) | ||||
Edible meat production value in kg | References | ||||
1.8–3.3 | 1.5–7 | 3–6 | 16–40 | FEAP (2022) | |
3–15 | 2–6 | 4–11 | 10–50 | 9–129 | Nijdam et al. (2012) |
2–7 (4) | 3–4 | 4–8 | 12–16 | Boyd (2013) | |
2.7 | 5.9 | 30 | MH (2017) | ||
1.8 | 3.2 | 18.5 | 14.5 | Nemry et al. (2001) | |
3.28 | MacLeod et al. (2020) |
Average daily dietary energy need per | References | ||||
2,373 kcal for 1969–1971 and 2,950 kcal for 2020 | Alexandratos & Bruinsma (2012) and FAO (2021) | ||||
3,025 kcal for forecast 2030 | OECD/FAO (2021) | ||||
Total climate change values of aquaculture (CO2e) | References | ||||
291.2 megaton (Mt) for 2008, 385 Mt for 2010 and 674.6 Mt for forecast 2030 | Hall et al. (2011) | ||||
245 Mt for 2017, 93% of which is calculated, and a forecast 263 Mt with the remaining 7% the share of aquaculture species in total emissions is about 0.49% (263 Mt/53.5 Gt) | MacLeod et al. (2020) | ||||
Edible meat production value in kg | References | ||||
1.8–3.3 | 1.5–7 | 3–6 | 16–40 | FEAP (2022) | |
3–15 | 2–6 | 4–11 | 10–50 | 9–129 | Nijdam et al. (2012) |
2–7 (4) | 3–4 | 4–8 | 12–16 | Boyd (2013) | |
2.7 | 5.9 | 30 | MH (2017) | ||
1.8 | 3.2 | 18.5 | 14.5 | Nemry et al. (2001) | |
3.28 | MacLeod et al. (2020) |
Industry studies supported by scientific methods are evaluated with solution-oriented approaches against the devastating effects of global climate change originating from the Anthropocene. For this purpose, salmon farms have set innovation plans in feed, transportation, and operations as priority targets in line with the targets of reducing carbon emissions in efforts to tackle climate change (Hogan 2021). In order to ensure sustainability, the leading global aquafeed factories in world production have started their plans for environmentally friendly low-emission feed production. These management plans are low-emission feed production based on low-emission feed ingredients without decreasing feed quality (HatcheryFeedManagement 2021), and the other is the on-farm planning of feed production to reduce the CF values caused by transporting the feed to the farm (HatcheryInternationalStaff 2021). The second private company mentioned continues to work on the production of feed ingredients that enables the conversion of methane into protein-based solutions and feed formulation with 10% lower CF than standard diets, in line with its sustainability goals (EFA News 2022; HatcheryInternational Staff 2022). Another private company aims to reduce the CF of seafood farming by 30% by 2030, saving 2 billion kg of CO2 per year (Cargill 2022).
In this study, in which the anthropogenic effects of aquaculture were determined, the CF expended of the rainbow trout farm, which was grown in concrete ponds using spring water, was evaluated and some suggestions were made to policymakers and producers.
MATERIALS AND METHODS
Management of concrete pond rainbow trout farming (CPRT)
This study is a follow-up study determining the CF (kg CO2e) expended in concrete pond rainbow trout farming (CPRT) from Türkiye and it stemmed from data used in the study of Diken & Koknaroglu (2022). Rainbow trout farming and management information can be followed in the cited article. In of this study, ethical approval is not required as farm records were used.
CF (kg CO2e) analysis of CPRT farming
The study data were obtained from the operating data of the Canlar Alabalık farm. In the design of the CF calculation, CF expended (kg CO2e kg−1) values were determined according to the total production of the CPRT in three different years. After calculating the CF expended values of the total production in three different years in which different rainbow trout were produced, adaptation was made according to APC. The CF (kg CO2e) inputs and outputs of CPRT were calculated according to the unit values in Table 2. The proximate composition of Diet-1 and 2 used consisted of 55% crude protein (CP), 14% crude oil (CO), 12% crude ash (CA), 1% crude fiber (CF), 3.900 Mcal ME kg−1; Diet-3 used consisted of 55% CP, 14% CO, 11.8% CA, 0.9% CF, 3.900 Mcal ME kg−1; Diet-4 used consisted of 55% CP, 14% CO, 12.5% CA, 0.9% CF, 3.900 Mcal ME kg−1; Diet-5 and 6 used consisted of 53% CP, 15% CO, 12% CA, 1% CF, 3.800 Mcal ME kg−1; Diet-7 and 8 used consisted of 48% CP, 18% CO, 11.5% CA, 1.2% CF, 4.100 Mcal ME kg−1; Diet-9 used consisted of 46% CP, 19% CO, 10% CA, 1.5% CF, 4.000 Mcal ME kg−1; Diet-10 to 14 used consisted of 45% CP, 20% CO, 9.5% CA, 1.7% CF, 4.000 Mcal ME kg−1; and Diet-15 used consisted of 48% CP, 16% CO, 16.5% CA, 1.6% CF, 3.815 Mcal ME kg−1, respectively. Considering proximate composition information, the diets were formulated according to feed ingredients (according to IAFFD (2020)'s feed ingredients’ proximate composition; fish meal, fish oil, soybean meal, wheat grain, wheat byproducts, vitamins, and minerals) provided in the prospectus (Diken & Koknaroglu 2022). The CF expended values of compound diets given in Table 3 were calculated by multiplying the usage rate of feed ingredients (Diken & Koknaroglu 2022) with the unit values of feed ingredients given in the literature (Table 2). CF expended on general management were values that were formed by management practices such as antibiotics, oxygen, chemicals, fuel, electricity, and labor in rainbow trout farming. CF expended on machinery, equipment, and construction was items that ensure the installation and continuity of the enterprise (Table 2). CF expended on transportation was the transportation value calculated by multiplying the transportation distance, the load, and the coefficient (Table 2). All calculations were analyzed with the method in Table 4 in relation to the number of items used according to the unit values given in Table 2. The CF input and production output per kg fish of the total production of harvested fish rainbow trout were calculated according to the analysis method given in Table 4. CF (kg CO2e) input for total production, kg harvested fish (), and output for production years are given in Table 5. The one-way ANOVA, followed by Tukey’s HSD test, was used to detect the differences between the groups at a significance of 5% (SPSSInc 2015).
Energy content of inputs (Mcal per kg of processed fish as) | |||
Items | Unit | Mcal unit−1 | References |
Fish fingerling | kg | 1.45 | Calculated according to Mehrabi et al. (2012) |
CF expended on consumed compound diet | |||
Items | Unit | kg CO2e unit−1 | |
Feed ingredients | |||
Fish meal | kg | 0.99 | Hognes et al. (2011) |
Fish oil | kg | 0.99 | Hognes et al. (2011) |
Soybean meal | kg | 0.541 | Hognes et al. (2011) |
Wheat grain | kg | 0.51 | Hognes et al. (2011) |
Wheat middlings | kg | 0.306 | Vellinga et al. (2013) |
Vitamin | kg | 1.62 | Rotz et al. (2019) |
Mineral | kg | 1.62 | Rotz et al. (2019) |
Pellets production | kg | 0.13 | Hognes et al. (2011) |
Diet-1 and 2 | kg | 1.08 | Calculated |
Diet-3 | kg | 1.08 | Calculated |
Diet-4 | kg | 1.08 | Calculated |
Diet-5 and 6 | kg | 1.01 | Calculated |
Diet-7 and 8 | kg | 0.98 | Calculated |
Diet-9 | kg | 0.97 | Calculated |
Diet-10–14 | kg | 0.97 | Calculated |
Diet-15 | kg | 0.96 | Calculated |
CF expended on general management | |||
Antibiotic | kg | 2.02 | Ecoinvent database v3.4 |
Vitamin | kg | 1.62 | Rotz et al. (2019) |
Oxygen | L | 0.2865 | Šulc & Ditl (2021) |
Commercial product with chloramine-T | kg | 0.97 | Ecoinvent database v3.4 (Calculated based on ammonia and chlorine values) |
Potassium permanganate | kg | 1.79 | Ecoinvent database v3.4 |
Hydrogen peroxide | L | 1.13 | Ecoinvent database v3.4 |
Formalin, 37% formaldehyde | L | 0.267 | Ecoinvent database v3.4 |
Salt | kg | 0.0389 | Ecoinvent database v3.4 |
Labor | h | 0.70 | Nguyen & Hermansen (2012) |
Electricity | kWh | 0.24 | Robertson et al. (2015) |
Diesel | L | 3.11 | Robertson et al. (2015) |
Gasoline | L | 2.74 | Robertson et al. (2015) |
CF expended on machinery, equipment, and construction | |||
Aluminum | kg | 8.24 | Sabnis et al. (2015) |
Fiberglass incubation channel | kg | 6.42 | Calculated (fiberglass, polyester, and galvanized, Hammond et al. (2011)) |
Glass (toughened) | kg | 1.27 | Hammond et al. (2011) |
Plastics (PVC) | kg | 2.61 | Hammond et al. (2011) |
Timber, softwood (air-dried, dressed) | kg | 0.83 | Hammond et al. (2011) |
Timber, softwood (air-dried, roughsawn) | kg | 0.58 | Hammond et al. (2011) |
Timber, softwood (particle board) | kg | 0.84 | Hammond et al. (2011) |
Stone | kg | 0.056 | Sabnis et al. (2015) |
Concrete | kg | 0.117 | Sabnis et al. (2015) |
Cement sand screed | kg | 0.145 | Hammond et al. (2011) |
Mortar (normal bricklaying) | kg | 0.208 | Hammond et al. (2011) |
Mortar (general plastering) | kg | 0.200 | Hammond et al. (2011) |
Limestone | kg | 0.032 | Hammond et al. (2011) |
Ceramic (tile) | kg | 0.74 | Hammond et al. (2011) |
Brick | kg | 0.22 | Sabnis et al. (2015) |
Rebar | kg | 1.06 | Taffese & Abegaz (2019) |
Iron strip | kg | 2.09 | Pomponi & Moncaster (2018) and Gan et al. (2017) |
Metal sheets | kg | 2.45 | Ecoinvent database V3.4 |
Excavation (0.6 m3) | h | 51.7 | Kawai (2011) |
Cage net and rope | kg | 8.13 | Ecoinvent database V3.4 |
CF expended on transportation | |||
Truck tonne kg | 0.206 | Robertson et al. (2015) | |
Energy content of outputs (Mcal per kg of processed fish as) | |||
Harvested/fresh weight fish | 1.93 | Calculated according to Welker et al. (2018) | |
Carcass and fillet | 1.02 and 0.72 | Calculated according to Tatıl (2019) | |
CF expended per 100 kcal food energy | |||
Harvested/fresh weight fish | 141 kcal per 100 g serving | Calculated according to Fry et al. (2018) |
Energy content of inputs (Mcal per kg of processed fish as) | |||
Items | Unit | Mcal unit−1 | References |
Fish fingerling | kg | 1.45 | Calculated according to Mehrabi et al. (2012) |
CF expended on consumed compound diet | |||
Items | Unit | kg CO2e unit−1 | |
Feed ingredients | |||
Fish meal | kg | 0.99 | Hognes et al. (2011) |
Fish oil | kg | 0.99 | Hognes et al. (2011) |
Soybean meal | kg | 0.541 | Hognes et al. (2011) |
Wheat grain | kg | 0.51 | Hognes et al. (2011) |
Wheat middlings | kg | 0.306 | Vellinga et al. (2013) |
Vitamin | kg | 1.62 | Rotz et al. (2019) |
Mineral | kg | 1.62 | Rotz et al. (2019) |
Pellets production | kg | 0.13 | Hognes et al. (2011) |
Diet-1 and 2 | kg | 1.08 | Calculated |
Diet-3 | kg | 1.08 | Calculated |
Diet-4 | kg | 1.08 | Calculated |
Diet-5 and 6 | kg | 1.01 | Calculated |
Diet-7 and 8 | kg | 0.98 | Calculated |
Diet-9 | kg | 0.97 | Calculated |
Diet-10–14 | kg | 0.97 | Calculated |
Diet-15 | kg | 0.96 | Calculated |
CF expended on general management | |||
Antibiotic | kg | 2.02 | Ecoinvent database v3.4 |
Vitamin | kg | 1.62 | Rotz et al. (2019) |
Oxygen | L | 0.2865 | Šulc & Ditl (2021) |
Commercial product with chloramine-T | kg | 0.97 | Ecoinvent database v3.4 (Calculated based on ammonia and chlorine values) |
Potassium permanganate | kg | 1.79 | Ecoinvent database v3.4 |
Hydrogen peroxide | L | 1.13 | Ecoinvent database v3.4 |
Formalin, 37% formaldehyde | L | 0.267 | Ecoinvent database v3.4 |
Salt | kg | 0.0389 | Ecoinvent database v3.4 |
Labor | h | 0.70 | Nguyen & Hermansen (2012) |
Electricity | kWh | 0.24 | Robertson et al. (2015) |
Diesel | L | 3.11 | Robertson et al. (2015) |
Gasoline | L | 2.74 | Robertson et al. (2015) |
CF expended on machinery, equipment, and construction | |||
Aluminum | kg | 8.24 | Sabnis et al. (2015) |
Fiberglass incubation channel | kg | 6.42 | Calculated (fiberglass, polyester, and galvanized, Hammond et al. (2011)) |
Glass (toughened) | kg | 1.27 | Hammond et al. (2011) |
Plastics (PVC) | kg | 2.61 | Hammond et al. (2011) |
Timber, softwood (air-dried, dressed) | kg | 0.83 | Hammond et al. (2011) |
Timber, softwood (air-dried, roughsawn) | kg | 0.58 | Hammond et al. (2011) |
Timber, softwood (particle board) | kg | 0.84 | Hammond et al. (2011) |
Stone | kg | 0.056 | Sabnis et al. (2015) |
Concrete | kg | 0.117 | Sabnis et al. (2015) |
Cement sand screed | kg | 0.145 | Hammond et al. (2011) |
Mortar (normal bricklaying) | kg | 0.208 | Hammond et al. (2011) |
Mortar (general plastering) | kg | 0.200 | Hammond et al. (2011) |
Limestone | kg | 0.032 | Hammond et al. (2011) |
Ceramic (tile) | kg | 0.74 | Hammond et al. (2011) |
Brick | kg | 0.22 | Sabnis et al. (2015) |
Rebar | kg | 1.06 | Taffese & Abegaz (2019) |
Iron strip | kg | 2.09 | Pomponi & Moncaster (2018) and Gan et al. (2017) |
Metal sheets | kg | 2.45 | Ecoinvent database V3.4 |
Excavation (0.6 m3) | h | 51.7 | Kawai (2011) |
Cage net and rope | kg | 8.13 | Ecoinvent database V3.4 |
CF expended on transportation | |||
Truck tonne kg | 0.206 | Robertson et al. (2015) | |
Energy content of outputs (Mcal per kg of processed fish as) | |||
Harvested/fresh weight fish | 1.93 | Calculated according to Welker et al. (2018) | |
Carcass and fillet | 1.02 and 0.72 | Calculated according to Tatıl (2019) | |
CF expended per 100 kcal food energy | |||
Harvested/fresh weight fish | 141 kcal per 100 g serving | Calculated according to Fry et al. (2018) |
Compound diets . | Feed ingredients (FI) . | FM . | FO . | SM . | WG . | WM . | V . | M . | PP . | Diet CF . |
---|---|---|---|---|---|---|---|---|---|---|
CFFI (kg CO2e kg−1) . | 0.99 . | 0.99 . | 0.541 . | 0.51 . | 0.306 . | 1.62 . | 1.62 . | 0.13 . | ||
1 and 2 | FI diet (%) | 79.78 | 8.81 | 1.00 | 8.91 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.01 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
3 | FI diet (%) | 80.00 | 8.78 | 0.50 | 9.22 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.00 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
4 | FI diet (%) | 80.00 | 8.78 | 0.50 | 9.22 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.00 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
5 and 6 | FI diet (%) | 64.30 | 9.40 | 19.80 | 4.00 | 1.50 | 0.50 | 0.50 | 1.01 | |
CFFI diet (kg CO2e kg−1) | 0.64 | 0.09 | 0.11 | 0.02 | 0.00 | 0.01 | 0.01 | 0.13 | ||
7 and 8 | FI diet (%) | 58.90 | 12.30 | 14.50 | 6.90 | 6.40 | 0.50 | 0.50 | 0.98 | |
CFFI diet (kg CO2e kg−1) | 0.58 | 0.12 | 0.08 | 0.04 | 0.02 | 0.01 | 0.01 | 0.13 | ||
9 | FI diet (%) | 50.47 | 14.48 | 23.15 | 9.23 | 1.67 | 0.50 | 0.50 | 0.97 | |
CFFI diet (kg CO2e kg−1) | 0.50 | 0.14 | 0.13 | 0.05 | 0.01 | 0.01 | 0.01 | 0.13 | ||
10–14 | FI diet (%) | 50.31 | 15.12 | 20.54 | 10.36 | 2.67 | 0.50 | 0.50 | 0.97 | |
CFFI diet (kg CO2e kg−1) | 0.50 | 0.15 | 0.11 | 0.05 | 0.01 | 0.01 | 0.01 | 0.13 | ||
15 | FI diet (%) | 55.50 | 11.00 | 19.00 | 4.00 | 9.50 | 0.50 | 0.50 | 0.96 | |
CFFI diet (kg CO2e kg−1) | 0.55 | 0.11 | 0.10 | 0.02 | 0.03 | 0.01 | 0.01 | 0.13 |
Compound diets . | Feed ingredients (FI) . | FM . | FO . | SM . | WG . | WM . | V . | M . | PP . | Diet CF . |
---|---|---|---|---|---|---|---|---|---|---|
CFFI (kg CO2e kg−1) . | 0.99 . | 0.99 . | 0.541 . | 0.51 . | 0.306 . | 1.62 . | 1.62 . | 0.13 . | ||
1 and 2 | FI diet (%) | 79.78 | 8.81 | 1.00 | 8.91 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.01 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
3 | FI diet (%) | 80.00 | 8.78 | 0.50 | 9.22 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.00 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
4 | FI diet (%) | 80.00 | 8.78 | 0.50 | 9.22 | 0.50 | 0.50 | 0.50 | 1.08 | |
CFFI diet (kg CO2e kg−1) | 0.79 | 0.09 | 0.00 | 0.05 | 0.00 | 0.01 | 0.01 | 0.13 | ||
5 and 6 | FI diet (%) | 64.30 | 9.40 | 19.80 | 4.00 | 1.50 | 0.50 | 0.50 | 1.01 | |
CFFI diet (kg CO2e kg−1) | 0.64 | 0.09 | 0.11 | 0.02 | 0.00 | 0.01 | 0.01 | 0.13 | ||
7 and 8 | FI diet (%) | 58.90 | 12.30 | 14.50 | 6.90 | 6.40 | 0.50 | 0.50 | 0.98 | |
CFFI diet (kg CO2e kg−1) | 0.58 | 0.12 | 0.08 | 0.04 | 0.02 | 0.01 | 0.01 | 0.13 | ||
9 | FI diet (%) | 50.47 | 14.48 | 23.15 | 9.23 | 1.67 | 0.50 | 0.50 | 0.97 | |
CFFI diet (kg CO2e kg−1) | 0.50 | 0.14 | 0.13 | 0.05 | 0.01 | 0.01 | 0.01 | 0.13 | ||
10–14 | FI diet (%) | 50.31 | 15.12 | 20.54 | 10.36 | 2.67 | 0.50 | 0.50 | 0.97 | |
CFFI diet (kg CO2e kg−1) | 0.50 | 0.15 | 0.11 | 0.05 | 0.01 | 0.01 | 0.01 | 0.13 | ||
15 | FI diet (%) | 55.50 | 11.00 | 19.00 | 4.00 | 9.50 | 0.50 | 0.50 | 0.96 | |
CFFI diet (kg CO2e kg−1) | 0.55 | 0.11 | 0.10 | 0.02 | 0.03 | 0.01 | 0.01 | 0.13 |
FM, fish meal, anchovy; FO, fish oil; SM, soybean meal; WG, wheat grain; WM, wheat middlings; V, vitamin; M, mineral; PP, pellets production; CF, carbon footprint expended. The difference is reflected in the calculation due to rounding.
Carbon footprint budget | |
A | CFCD: expended on consumed compound diet |
B | CFGM: CF expended on general management |
C | CFT: CF expended on transportation |
D | CFMEC: CF expended on machinery, equipment, and construction |
Carbon footprint expended for outputs | |
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Carbon footprint budget | |
A | CFCD: expended on consumed compound diet |
B | CFGM: CF expended on general management |
C | CFT: CF expended on transportation |
D | CFMEC: CF expended on machinery, equipment, and construction |
Carbon footprint expended for outputs | |
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10 | |
11 |
Items . | First year (2016–2017) 260.04 t . | Second year (2017–2018) 320.44 t . | Third year (2018–2019) 366.44 t . | Mean ± SD . | ||
---|---|---|---|---|---|---|
CF budget | CF expended on consumed compound diet (CFCD) | 309.452,48 | 332.902,55 | 371.401,94 | 337.918,99 ± 31.277,9a | |
1.19 | 1.04 | 1.01 | 1.08 ± 0.10 | |||
CF expended on general management (CFGM) | 28.694,08 | 25.911,92 | 27.261,79 | 27.289,27 ± 1.391,29c | ||
0.11 | 0.08 | 0.07 | 0.09 ± 0.02 | |||
CF expended on transportation (CFT) | 105.758,85 | 113.795,38 | 126.862,52 | 115.472,25 ± 10.651,30b | ||
0.41 | 0.36 | 0.35 | 0.37 ± 0.03 | |||
CF expended on machinery, equipment, and construction (CFMEC) | 74.955,77 | 74.955,77 | 74.955,77 | 74.955,77b | ||
0.29 | 0.23 | 0.20 | 0.24 ± 0.04 | |||
Total CF expended | 518.861,19 | 547.565,62 | 600.482,02 | 555.636,28 ± 41.404,61 | ||
* | 2.00 | 1.71 | 1.64 | 1.78 ± 0.19 | ||
CF expended for outputs | CF expended for compound diet per day | 2.161,92 | 2.262,67 | 2.450,95 | 2.291,85 ± 146,71 | |
0.01 | 0.01 | 0.01 | 0.01 ± 0.00 | |||
CF expended per kg live weight gain | 2.00 | 1.71 | 1.64 | 1.78 ± 0.19 | ||
CF expended per kg carcass gained during feeding | 2.46 | 2.11 | 2.02 | 2.20 ± 0.23 | ||
CF expended per kg fillet gained during feeding | 3.47 | 2.97 | 2.85 | 3.10 ± 0.33 | ||
CF expended per Mcal energy deposited in harvested fish gained during feeding | 1.03 | 0.89 | 0.85 | 0.92 ± 0.10 | ||
CF expended per Mcal energy deposited in carcass during feeding | 1.96 | 1.68 | 1.61 | 1.75 ± 0.18 | ||
CF expended per Mcal energy deposited in fillet during feeding | 2.76 | 2.37 | 2.27 | 2.46 ± 0.26 | ||
CF expended per kg of protein deposited in harvested fish gained during feeding | 11.93 | 10.23 | 9.81 | 10.66 ± 1.12 | ||
CF expended per kg of protein deposited in carcass gained during feeding | 13.70 | 11.75 | 11.26 | 12.24 ± 1.29 | ||
CF expended per kg of protein deposited in fillet gained during feeding | 19.29 | 16.55 | 15.87 | 17.24 ± 1.81 | ||
CF expended per Mcal of cultural energy expended during production | 0.36 | 0.36 | 0.36 | 0.36 ± 0.00 | ||
Cultural energy expended per Mcal of CF expended during production | 2.74 | 2.60 | 2.37 | 2.57 ± 0.19 | ||
CF expended per 100 kcal food energy in harvested fish (kg CO2e) | 0.1415 | 0.1212 | 0.1162 | 0.1263 ± 0.0134 |
Items . | First year (2016–2017) 260.04 t . | Second year (2017–2018) 320.44 t . | Third year (2018–2019) 366.44 t . | Mean ± SD . | ||
---|---|---|---|---|---|---|
CF budget | CF expended on consumed compound diet (CFCD) | 309.452,48 | 332.902,55 | 371.401,94 | 337.918,99 ± 31.277,9a | |
1.19 | 1.04 | 1.01 | 1.08 ± 0.10 | |||
CF expended on general management (CFGM) | 28.694,08 | 25.911,92 | 27.261,79 | 27.289,27 ± 1.391,29c | ||
0.11 | 0.08 | 0.07 | 0.09 ± 0.02 | |||
CF expended on transportation (CFT) | 105.758,85 | 113.795,38 | 126.862,52 | 115.472,25 ± 10.651,30b | ||
0.41 | 0.36 | 0.35 | 0.37 ± 0.03 | |||
CF expended on machinery, equipment, and construction (CFMEC) | 74.955,77 | 74.955,77 | 74.955,77 | 74.955,77b | ||
0.29 | 0.23 | 0.20 | 0.24 ± 0.04 | |||
Total CF expended | 518.861,19 | 547.565,62 | 600.482,02 | 555.636,28 ± 41.404,61 | ||
* | 2.00 | 1.71 | 1.64 | 1.78 ± 0.19 | ||
CF expended for outputs | CF expended for compound diet per day | 2.161,92 | 2.262,67 | 2.450,95 | 2.291,85 ± 146,71 | |
0.01 | 0.01 | 0.01 | 0.01 ± 0.00 | |||
CF expended per kg live weight gain | 2.00 | 1.71 | 1.64 | 1.78 ± 0.19 | ||
CF expended per kg carcass gained during feeding | 2.46 | 2.11 | 2.02 | 2.20 ± 0.23 | ||
CF expended per kg fillet gained during feeding | 3.47 | 2.97 | 2.85 | 3.10 ± 0.33 | ||
CF expended per Mcal energy deposited in harvested fish gained during feeding | 1.03 | 0.89 | 0.85 | 0.92 ± 0.10 | ||
CF expended per Mcal energy deposited in carcass during feeding | 1.96 | 1.68 | 1.61 | 1.75 ± 0.18 | ||
CF expended per Mcal energy deposited in fillet during feeding | 2.76 | 2.37 | 2.27 | 2.46 ± 0.26 | ||
CF expended per kg of protein deposited in harvested fish gained during feeding | 11.93 | 10.23 | 9.81 | 10.66 ± 1.12 | ||
CF expended per kg of protein deposited in carcass gained during feeding | 13.70 | 11.75 | 11.26 | 12.24 ± 1.29 | ||
CF expended per kg of protein deposited in fillet gained during feeding | 19.29 | 16.55 | 15.87 | 17.24 ± 1.81 | ||
CF expended per Mcal of cultural energy expended during production | 0.36 | 0.36 | 0.36 | 0.36 ± 0.00 | ||
Cultural energy expended per Mcal of CF expended during production | 2.74 | 2.60 | 2.37 | 2.57 ± 0.19 | ||
CF expended per 100 kcal food energy in harvested fish (kg CO2e) | 0.1415 | 0.1212 | 0.1162 | 0.1263 ± 0.0134 |
= one kg harvested/fresh weight/marketed fish, whole body rainbow trout. *CF expended for per kg live weight gain and CF expended for kg harvested fish gained during feeding. t = tonne year−1. CF, carbon footprint. The difference is reflected in the calculation due to rounding. SD, standard deviation, abcMeans with different superscripts in the same column differ (P < 0.05).
RESULTS AND DISCUSSION
This study was carried out on a private farm with an annual project production capacity of 350 tonnes APC. Farm production was realized as 74.4, 91.55, and 104.70% of the APC in the first, second, and third years, respectively. The ratio of 122 inland finfish farming facilities with a project capacity of 251–500 tonnes year−1, where almost all of Türkiye's inland finfish production realized by rainbow trout is 25.23% (GDFA 2021). Based on APC value, this private farm is included in this group of assessments based on project capacities.
CF budget
According to the CF budget or total CF values of CPRT farming in Table 5, the value of APC is determined in Table 6. This value reflects the CF project value for the establishment of CPRT, which is not taken into account in the projects when the farms are established but is likely to be taken into account in the future.
Items . | The linear regression equation . | kg CO2e . | |
---|---|---|---|
CF budget | CF expended on consumed compound diet | y = −0.0017x + 1.6179 (R² = 0.9056) | 1.02 |
CF expended on general management | y = −0.0003x + 0.1978 (R² = 0.9256) | 0.09 | |
CF expended on transportation | y = −0.0006x + 0.5534 (R² = 0.9077) | 0.34 | |
CF expended on machinery, equipment, and construction | y = −0.0008x + 0.4923 (R² = 0.9915) | 0.21 | |
Total CF expended | y = −0.0034x + 2.8614 (R² = 0.9344) | 1.67 | |
CF expended on consumed compound diet | y = 0.0207x + 54.233 (R² = 0.9974) | 61.48% | |
CF expended on general management | y = −0.0095x + 7.9344 (R² = 0.9331) | 4.61% | |
CF expended on transportation | y = 0.007x + 18.563 (R² = 0.9987) | 21.01% | |
CF expended on machinery, equipment, and construction | y = −0.0182x + 19.269 (R² = 0.9569) | 12.90% | |
CF expended for outputs | CF expended per kg live weight gain | y = −0.0034x + 2.8614 (R² = 0.9344) | 1.67 |
CF expended for kg carcass gained during feeding | y = −0.0042x + 3.521 (R² = 0.9352) | 2.05 | |
CF expended for kg fillet gained during feeding | y = −0.0059x + 4.96 (R² = 0.9352) | 2.90 | |
CF expended per Mcal energy deposited in harvested fish gained during feeding | y = −0.0018x + 1.4781 (R² = 0.9352) | 0.85 | |
CF expended per Mcal energy deposited in carcass during feeding | y = −0.0033x + 2.8036 (R² = 0.9352) | 1.65 | |
CF expended per Mcal energy deposited in fillet during feeding | y = −0.0047x + 3.9494 (R² = 0.9352) | 2.30 | |
CF expended per kg of protein deposited in harvested fish gained during feeding | y = −0.0203x + 17.078 (R² = 0.9352) | 9.97 | |
CF expended per kg of protein deposited in carcass gained during feeding | y = −0.0233x + 19.605 (R² = 0.9352) | 11.45 | |
CF expended per kg of protein deposited in fillet gained during feeding | y = −0.0329x + 27.617 (R² = 0.9352) | 16.10 | |
Cultural energy expended per Mcal of CF expended during production | y = −0.0034x + 3.6557 (R² = 0.9569) | 2.47 | |
CF expended of calories deposited in harvested fish gained during feeding | y = −0.0002428x + 0.2029332 (R² = 0.9344) | 0.1173kg CO2e/100 kcal |
Items . | The linear regression equation . | kg CO2e . | |
---|---|---|---|
CF budget | CF expended on consumed compound diet | y = −0.0017x + 1.6179 (R² = 0.9056) | 1.02 |
CF expended on general management | y = −0.0003x + 0.1978 (R² = 0.9256) | 0.09 | |
CF expended on transportation | y = −0.0006x + 0.5534 (R² = 0.9077) | 0.34 | |
CF expended on machinery, equipment, and construction | y = −0.0008x + 0.4923 (R² = 0.9915) | 0.21 | |
Total CF expended | y = −0.0034x + 2.8614 (R² = 0.9344) | 1.67 | |
CF expended on consumed compound diet | y = 0.0207x + 54.233 (R² = 0.9974) | 61.48% | |
CF expended on general management | y = −0.0095x + 7.9344 (R² = 0.9331) | 4.61% | |
CF expended on transportation | y = 0.007x + 18.563 (R² = 0.9987) | 21.01% | |
CF expended on machinery, equipment, and construction | y = −0.0182x + 19.269 (R² = 0.9569) | 12.90% | |
CF expended for outputs | CF expended per kg live weight gain | y = −0.0034x + 2.8614 (R² = 0.9344) | 1.67 |
CF expended for kg carcass gained during feeding | y = −0.0042x + 3.521 (R² = 0.9352) | 2.05 | |
CF expended for kg fillet gained during feeding | y = −0.0059x + 4.96 (R² = 0.9352) | 2.90 | |
CF expended per Mcal energy deposited in harvested fish gained during feeding | y = −0.0018x + 1.4781 (R² = 0.9352) | 0.85 | |
CF expended per Mcal energy deposited in carcass during feeding | y = −0.0033x + 2.8036 (R² = 0.9352) | 1.65 | |
CF expended per Mcal energy deposited in fillet during feeding | y = −0.0047x + 3.9494 (R² = 0.9352) | 2.30 | |
CF expended per kg of protein deposited in harvested fish gained during feeding | y = −0.0203x + 17.078 (R² = 0.9352) | 9.97 | |
CF expended per kg of protein deposited in carcass gained during feeding | y = −0.0233x + 19.605 (R² = 0.9352) | 11.45 | |
CF expended per kg of protein deposited in fillet gained during feeding | y = −0.0329x + 27.617 (R² = 0.9352) | 16.10 | |
Cultural energy expended per Mcal of CF expended during production | y = −0.0034x + 3.6557 (R² = 0.9569) | 2.47 | |
CF expended of calories deposited in harvested fish gained during feeding | y = −0.0002428x + 0.2029332 (R² = 0.9344) | 0.1173kg CO2e/100 kcal |
Compound diets . | Carbon footprint (kg CO2e) expended . | % . |
---|---|---|
Diet-1 (150–300 μ) | 80.67 ± 38.03d | 0.02 ± 0.01 |
Diet-2 (Granular-1; 300–500 μ) | 430.25 ± 53.78d | 0.12 ± 0.02 |
Diet-3 (Granular-2; 500–800 μ) | 566.53 ± 65.65d | 0.16 ± 0.02 |
Diet-4 (Granular-3; 800–1,200 μ) | 898.78 ± 105.53d | 0.26 ± 0.03 |
Diet-5 (1 mm) | 2.435,85 ± 145.48d | 0.72 ± 0.09 |
Diet-6 (1.5 mm) | 3.712,57 ± 162.00d | 1.09 ± 0.13 |
Diet-7 (2 mm) | 8.694,64 ± 284.14d | 2.58 ± 0.29 |
Diet-8 (2.5 mm) | 4.347,32 ± 512.25d | 1.29 ± 0.21 |
Diet-9 (3 mm) | 71.852,81 ± 8.106,64b | 21.27 ± 1.07 |
Diet-10 (4 mm) | 56.354,94 ± 13.944,23c | 16.55 ± 2.62 |
Diet-11 (5 mm) | 82.278,21 ± 4.383,02ab | 24.43 ± 1.23 |
Diet-12 (6 mm) | 96.608,46 ± 8.366,54a | 28.65 ± 1.63 |
Σ (Diet-9/3 mm, Diet-10/4 mm, Diet-11/5 mm, Diet-12/6 mm) | 90.90 ± 1.02 | |
Diet-13 (8 mm) | 4.347,38 ± 483.04d | 1.29 ± 0.14 |
Diet-14 (10 mm) | 4.492,29 ± 846.36d | 1.32 ± 0.13 |
Diet-15 (10 mm) | 845.18 ± 120.40d | 0.25 ± 0.01 |
Compound diets . | Carbon footprint (kg CO2e) expended . | % . |
---|---|---|
Diet-1 (150–300 μ) | 80.67 ± 38.03d | 0.02 ± 0.01 |
Diet-2 (Granular-1; 300–500 μ) | 430.25 ± 53.78d | 0.12 ± 0.02 |
Diet-3 (Granular-2; 500–800 μ) | 566.53 ± 65.65d | 0.16 ± 0.02 |
Diet-4 (Granular-3; 800–1,200 μ) | 898.78 ± 105.53d | 0.26 ± 0.03 |
Diet-5 (1 mm) | 2.435,85 ± 145.48d | 0.72 ± 0.09 |
Diet-6 (1.5 mm) | 3.712,57 ± 162.00d | 1.09 ± 0.13 |
Diet-7 (2 mm) | 8.694,64 ± 284.14d | 2.58 ± 0.29 |
Diet-8 (2.5 mm) | 4.347,32 ± 512.25d | 1.29 ± 0.21 |
Diet-9 (3 mm) | 71.852,81 ± 8.106,64b | 21.27 ± 1.07 |
Diet-10 (4 mm) | 56.354,94 ± 13.944,23c | 16.55 ± 2.62 |
Diet-11 (5 mm) | 82.278,21 ± 4.383,02ab | 24.43 ± 1.23 |
Diet-12 (6 mm) | 96.608,46 ± 8.366,54a | 28.65 ± 1.63 |
Σ (Diet-9/3 mm, Diet-10/4 mm, Diet-11/5 mm, Diet-12/6 mm) | 90.90 ± 1.02 | |
Diet-13 (8 mm) | 4.347,38 ± 483.04d | 1.29 ± 0.14 |
Diet-14 (10 mm) | 4.492,29 ± 846.36d | 1.32 ± 0.13 |
Diet-15 (10 mm) | 845.18 ± 120.40d | 0.25 ± 0.01 |
The difference is reflected in the calculation due to rounding. SD, standard deviation, abcdMeans with different superscripts in the same column differ (P< 0.05).
Items . | Carbon footprint expended (kg CO2e) . | % . |
---|---|---|
Labor | 12.705,00a | 46.64 ± 2.38 |
Diesel | 9.081,20 ± 1.613,61b | 33.14 ± 4.22 |
Electricity | 3.434,69 ± 578.23c | 12.65 ± 2.47 |
Gasoline | 799.17 ± 259.34d | 2.90 ± 0.80 |
Antibiotic | 201.66 ± 1.17d | 0.74 ± 0.04 |
Vitamin | 178.74 ± 15.40d | 0.66 ± 0.08 |
Oxygen | 14.80 ± 7.07d | 0.05 ± 0.02 |
Formalin, 37% formaldehyde | 494.93 ± 49.32d | 1.82 ± 0.27 |
Potassium permanganate | 232.10 ± 12.79d | 0.85 ± 0.08 |
Hydrogen peroxide | 69.68 ± 14.22d | 0.26 ± 0.07 |
Commercial product with chloramine-T | 77.27 ± 13.63d | 0.28 ± 0.06 |
Salt | 0.02 ± 0.00d | 0.00 ± 0.00 |
Items . | Carbon footprint expended (kg CO2e) . | % . |
---|---|---|
Labor | 12.705,00a | 46.64 ± 2.38 |
Diesel | 9.081,20 ± 1.613,61b | 33.14 ± 4.22 |
Electricity | 3.434,69 ± 578.23c | 12.65 ± 2.47 |
Gasoline | 799.17 ± 259.34d | 2.90 ± 0.80 |
Antibiotic | 201.66 ± 1.17d | 0.74 ± 0.04 |
Vitamin | 178.74 ± 15.40d | 0.66 ± 0.08 |
Oxygen | 14.80 ± 7.07d | 0.05 ± 0.02 |
Formalin, 37% formaldehyde | 494.93 ± 49.32d | 1.82 ± 0.27 |
Potassium permanganate | 232.10 ± 12.79d | 0.85 ± 0.08 |
Hydrogen peroxide | 69.68 ± 14.22d | 0.26 ± 0.07 |
Commercial product with chloramine-T | 77.27 ± 13.63d | 0.28 ± 0.06 |
Salt | 0.02 ± 0.00d | 0.00 ± 0.00 |
The difference is reflected in the calculation due to rounding. SD, standard deviation, abcdMeans with different superscripts in the same column differ (P< 0.05).
Carbon footprint expended on consumed compound diet (CFCD)
CF input for the total production of harvested fish as kg is given in Table 5. First, second, and third years, and average CFCD values per kg of harvested fish were 1.19, 1.04, 1.01, and 1.08 kg CO2e, respectively (Table 5). According to the three-year CFCD values, when the farm is reared with an APC, the CFCD value will be 1.02 kg CO2e (Table 6). Cage rainbow trout farming in the same basin has a lower CFCD mean of 0.82 kg CO2e values (Diken et al. 2022; Table 9). CF shares of diets in CFCD are given in Figure 2. It has been determined that CFCD constituted 59.64, 60.80, 61.85, and 60.76% of the total kg CO2e expended for the first, second, and third years, and average, respectively. Because of the high values of emissions associated with fishmeal with high protein values and emissions due to land-use change (soybean production), feed emissions were high in salmonids (MacLeod et al. 2020). An increase in the CFCD was observed due to increased feed consumption as the fish grew. The CFCD ratio of the 3, 4, 5, and 6 mm compound diets of the growing-out period was calculated as 90.90% (P < 0.05) (Table 7). It has been stated that there is a relationship between CF analysis and energy calculations (Flos & Reig 2017). With this expression, a similar relationship was found between the 73.69% of the cultural energy expended on consumed compound diet share of CPRT in the cultural energy budget (Diken & Koknaroglu 2022) and the 60.76% of the CFCD share in CPRT was calculated in this study. Eighty-five per cent of the total CF feed share in caged salmon production reported by Ziegler et al. (2020) and 73.69% of the CFCD share in cage rainbow trout reported by Diken et al. (2022) and 60.72% of the CFCD shares in CPRT in this study reveal the differences in the production systems of aquaculture (Table 9).
Rainbow trout farmed in concrete ponds (CPRT) | ||||
CF expended on consumed compound diet (CFCD) | ||||
First | Second | Third | Mean | APC |
1.19 kg CO2e; 59.64% | 1.04 kg CO2e; 60.85% | 1.01 kg CO2e; 61.48% | 1.08 kg CO2e; 60.76% | 1.02 kg CO2e; 61.85% |
Referenced citations | ||||
mean 0.82 kg CO2e and 73.69% cage RT (Diken et al. 2022) and 73.69% salmon cage (Ziegler et al. 2020) | ||||
CF expended on general management (CFGM) | ||||
0.11 kg CO2e; 5.53% | 0.08 kg CO2e; 4.73% | 0.07 kg CO2e; 4.54% | 0.09 kg CO2e; 4.93% | 0.09 kg CO2e; 4.61% |
Referenced citation | ||||
mean 0.16 kg CO2e and 13.08% cage RT (Diken et al. 2022) | ||||
CF expended on transportation (CFT) | ||||
0.41 kg CO2e; 20.38% | 0.36 kg CO2e; 20.78% | 0.35 kg CO2e; 21.13% | 0.37 kg CO2e; 20.76% | 0.34 kg CO2e; 21.01% |
Referenced citation | ||||
mean 0.03 and 2.52% cage RT (Diken et al. 2022) | ||||
CF expended on machinery, equipment, and construction (CFMEC) | ||||
0.29 kg CO2e; 14.45% | 0.23 kg CO2e; 13.69% | 0.20 kg CO2e; 12.48% | 0.24 kg CO2e; 13.54% | 0.21 kg CO2e; 12.90% |
mean 0.13 kg CO2e and 10.71% cage RT (Diken et al. 2022) | ||||
Total CF expended | ||||
2.00 | 1.71 | 1.64 | 1.78 | 1.67 |
Referenced citations | ||||
General | 1.8–3.3 kg CO2e (FEAP 2022) and 3.27 kg CO2e (MacLeod et al. 2020) and 2–7 kg CO2e (Boyd 2013) and 3–15 kg CO2e (Nijdam et al. 2012) | |||
Freshwater fish | 3.47 kg CO2e (MacLeod et al. 2020) | |||
Marine fish | 5.18 kg CO2e (MacLeod et al. 2020) | |||
Rainbow trout | 1.13 kg CO2e cage (Diken et al. 2022) and 2.75 kg CO2e flow-through (Aubin et al. 2009) and different systems 250–300 g 1.76–1.85 kg CO2e, 900–1,500 g 1.96–2.29 kg CO2e, and 2,000–3,000 g 2.43–2.76 kg CO2e (Papatryphon et al. 2004) | |||
Salmonids | 3.17 kg CO2e (MacLeod et al. 2020) | |||
Atlantic salmon | 2.9 kg CO2e (MH 2017) and 7.01 kg CO2e RAS and 3.39 kg CO2e cage (Liu et al. 2016) and 2.16 kg CO2e (Pelletier et al. 2009) and 1.90–2.77 kg CO2e different systems (Ayer & Tyedmers 2009) and 1.2–2.7 kg CO2e (Pelletier & Tyedmers 2007) | |||
Cyrinids | 3.25 kg CO2e (MacLeod et al. 2020) | |||
Indian carp | 2.92 kg CO2e (MacLeod et al. 2020) and 1.84 (Robb et al. 2017) | |||
Pangasisus | 5.91 kg CO2e big farm, 6.73 kg CO2e small farm (Robb et al. 2017) | |||
Catfish | 3.05 kg CO2e catfish (MacLeod et al. 2020) and 1.37 striped catfish culture (Robb et al. 2017) | |||
Tilapia | 3.70 kg CO2e (MacLeod et al. 2020) and 5 kg CO2e RAS (Hagos 2012) and 1.58 kg CO2e Nile tilapia (Robb et al. 2017) and 2.10 kg CO2e Indonesian tilapia (Pelletier & Tyedmers 2010) | |||
Cobia | 8 kg CO2e cage (Hagos 2012) |
Rainbow trout farmed in concrete ponds (CPRT) | ||||
CF expended on consumed compound diet (CFCD) | ||||
First | Second | Third | Mean | APC |
1.19 kg CO2e; 59.64% | 1.04 kg CO2e; 60.85% | 1.01 kg CO2e; 61.48% | 1.08 kg CO2e; 60.76% | 1.02 kg CO2e; 61.85% |
Referenced citations | ||||
mean 0.82 kg CO2e and 73.69% cage RT (Diken et al. 2022) and 73.69% salmon cage (Ziegler et al. 2020) | ||||
CF expended on general management (CFGM) | ||||
0.11 kg CO2e; 5.53% | 0.08 kg CO2e; 4.73% | 0.07 kg CO2e; 4.54% | 0.09 kg CO2e; 4.93% | 0.09 kg CO2e; 4.61% |
Referenced citation | ||||
mean 0.16 kg CO2e and 13.08% cage RT (Diken et al. 2022) | ||||
CF expended on transportation (CFT) | ||||
0.41 kg CO2e; 20.38% | 0.36 kg CO2e; 20.78% | 0.35 kg CO2e; 21.13% | 0.37 kg CO2e; 20.76% | 0.34 kg CO2e; 21.01% |
Referenced citation | ||||
mean 0.03 and 2.52% cage RT (Diken et al. 2022) | ||||
CF expended on machinery, equipment, and construction (CFMEC) | ||||
0.29 kg CO2e; 14.45% | 0.23 kg CO2e; 13.69% | 0.20 kg CO2e; 12.48% | 0.24 kg CO2e; 13.54% | 0.21 kg CO2e; 12.90% |
mean 0.13 kg CO2e and 10.71% cage RT (Diken et al. 2022) | ||||
Total CF expended | ||||
2.00 | 1.71 | 1.64 | 1.78 | 1.67 |
Referenced citations | ||||
General | 1.8–3.3 kg CO2e (FEAP 2022) and 3.27 kg CO2e (MacLeod et al. 2020) and 2–7 kg CO2e (Boyd 2013) and 3–15 kg CO2e (Nijdam et al. 2012) | |||
Freshwater fish | 3.47 kg CO2e (MacLeod et al. 2020) | |||
Marine fish | 5.18 kg CO2e (MacLeod et al. 2020) | |||
Rainbow trout | 1.13 kg CO2e cage (Diken et al. 2022) and 2.75 kg CO2e flow-through (Aubin et al. 2009) and different systems 250–300 g 1.76–1.85 kg CO2e, 900–1,500 g 1.96–2.29 kg CO2e, and 2,000–3,000 g 2.43–2.76 kg CO2e (Papatryphon et al. 2004) | |||
Salmonids | 3.17 kg CO2e (MacLeod et al. 2020) | |||
Atlantic salmon | 2.9 kg CO2e (MH 2017) and 7.01 kg CO2e RAS and 3.39 kg CO2e cage (Liu et al. 2016) and 2.16 kg CO2e (Pelletier et al. 2009) and 1.90–2.77 kg CO2e different systems (Ayer & Tyedmers 2009) and 1.2–2.7 kg CO2e (Pelletier & Tyedmers 2007) | |||
Cyrinids | 3.25 kg CO2e (MacLeod et al. 2020) | |||
Indian carp | 2.92 kg CO2e (MacLeod et al. 2020) and 1.84 (Robb et al. 2017) | |||
Pangasisus | 5.91 kg CO2e big farm, 6.73 kg CO2e small farm (Robb et al. 2017) | |||
Catfish | 3.05 kg CO2e catfish (MacLeod et al. 2020) and 1.37 striped catfish culture (Robb et al. 2017) | |||
Tilapia | 3.70 kg CO2e (MacLeod et al. 2020) and 5 kg CO2e RAS (Hagos 2012) and 1.58 kg CO2e Nile tilapia (Robb et al. 2017) and 2.10 kg CO2e Indonesian tilapia (Pelletier & Tyedmers 2010) | |||
Cobia | 8 kg CO2e cage (Hagos 2012) |
RT, rainbow trout.
The increase in production caused an increase in CFCD and total CF as it would also increase feed consumption due to feed conversion rate (FCR), which was also stated by Ziegler et al. (2020). Adhikari et al. (2013) reported that feed constitutes 90% of the CF in different aquaculture culture systems in India. Although this result is above the CPRT's CF value, it reveals the necessity of studying the CF values of species (species-specific) and culture system (culture-specific) differences in aquaculture on a national and global scale. Depending on the feed ingredients of the trout feed, the climate change potential (kg CO2e) of the plant-based low fisheries diet was 6% lower than the fishmeal-based standard diet (Boissy et al. 2011). This situation reveals that the CF of feed formulations can be improved in trout farming. da Silva Pires et al. (2022) reported that strategies reducing the influence of gathering individual feed ingredients from different production systems and distances to make the final feed on the environmental impact is preferred in the LCA analysis of aquaculture. This would also be reflected in the lesser global warming effect of aquafeeds. This is consistent with the statement that a high impact of CFCD on the sustainability of CPRT rearing systems was the case in the present study.
Carbon footprint expended on general management (CFGM)
First, second, and third years, and average CFGM values per kg of harvested fish were 0.11, 0.08, 0.07, and 0.09 kg CO2e, respectively (Table 5). According to the three-year CFGM values, when the farm is reared with an APC, the CFGM value will be 0.09 kg CO2e (Table 6). This value was determined between 0.11 and 0.19 kg CO2e in cage rainbow trout farming (Diken et al. 2022; Table 9). The shares of CFGM in the total kg CO2e expended were calculated in the first, second, and third years, and the average was 5.53, 4.73, 4.54, and 4.93%, respectively (Figure 2). Labor had an average share of 46.64% in CFGM and an average share of 2.30% in total CO2e expended (P < 0.05) (Table 8). The shares of diesel and electricity in CFGM were calculated as 33.14 and 12.65%, respectively (P < 0.05). The shares of these three items in total CO2e expended were determined as approximately 1.63% diesel and 0.62% electricity, respectively (Table 8).
Carbon footprint expended on transportation (CFT)
Since fish farming is an integrated facility from egg to harvested fish, transportation only includes the value at which the compound diet is transported. Depending on the annual production amount, due to the increased feed consumption, also the total CFT increased. The total CFT value in the second and third years increased by 7.60 and 11.48%, respectively, compared with the previous year. On the other hand, production increased by 23.23 and 14.36, respectively. First, second, and third years, and their average CFT values per kg of harvested fish were 0.41, 0.36, 0.35, and 0.37 kg CO2e, respectively (Table 5). The shares of CFT in the total kg CO2e expended were calculated in the first, second, and third years and the average was 20.38, 20.78, 21.13, and 20.76%, respectively (Figure 2). Since the percent change in the total CFT value remained lower than the percent change in the production change value, the CFT value per kg decreased over the years. According to the three-year CFT values, when the farm is reared with an APC, the CFT value will be 0.34 kg CO2e (Table 6). This value was determined between 0.01 and 0.06 kg CO2e in cage rainbow trout farming (Diken et al. 2022; Table 9). Here, attention should be paid to the transportation differences between the two fish farmings (Diken et al. 2022). Similarly, it is reported that the consumed compound diets and compound diets transportation depending on the FCR values of rainbow trout farms produced in Karacaören-I Dam Lake in the same basin caused an increase in CF values of the basin (Diken 2022).
The recent reports highlight the importance of reduction of distances between feed production and usage sites, employment of feed production facilities in aquaculture sites, and selection of locally available feed ingredients in diet formulations to reduce transportation emission or preference for low-carbon emission feedstuffs in diets to reduce the environmental impact of aquaculture (HatcheryFeedManagement 2021; HatcheryInternationalStaff 2021; da Silva Pires et al. 2022). Likewise, our results support the need to decrease CFCD and CFT associated with diet and transport in CPRT farming systems.
Carbon footprint expended on machinery, equipment, and construction (CFMEC)
Since machinery, equipment, and construction were fixed items, the total value of CFMEC has been calculated at the same value for three years (Table 5). However, it was determined that the kg value of the harvested fish decreased depending on the production amount. The production of the first, second, and third years and their average were calculated as 0.29, 0.23, 0.20, and 0.24, respectively. According to the three-year CFMEC values, when the farm is reared with an APC, the CFMEC value will be 0.21 kg CO2e (Table 6). The shares of CFMEC in the total kg CO2e expended were calculated as the first, second, and third years and the average was 14.45, 13.69, 12.48, and 13.54%, respectively (Figure 2). This value was determined between 0.09 and 0.16 kg CO2e in cage rainbow trout farming (Diken et al. 2022; Table 9). Concrete constitutes 42.08% of CFMEC (Figure 3). According to the average CFMEC share is 13.54% as given in Figure 2, the share of concrete in the total CF expended is 6.50%. According to the average total CF expended value, it can be stated that the CF expended value of the concrete in the production of per kg rainbow trout was 0.12 kg CO2e (Table 5; Figures 2 and 3).
Total carbon footprint expended
The kg value of total CO2e expended can also be used as CO2e expended per kg live weight gain and CO2e expended per kg harvested fish. The increase in production has increased the CF budget, that is, the total amount of CF. However, the total kg CO2e value decreased. The kg CO2e value against the annual tonne production of the first, second, and third years was calculated as 260.04 vs 2.00, 320.44 vs 1.71, and 366.44 vs 1.64, respectively (Table 5).
According to many reports, aquaculture is the most efficient-food animal protein producer compared with other farm animals’ production (Table 1). In this report, it is determined as 1.8–3.3, 3.27, 2–7, and 3–15 kg CO2 per kg of edible products. The values showed that CF expended per kg harvested fish decreases depending on the annual production capacity and the values that should be made according to the APC are also lower than the values in these reports. The CF of CPRT is much lower than the overall CF values in the MacLeod et al. (2020) report on world freshwater and marine fish farming given in Table 9. Therefore, microdata of aquaculture such as CPRT will make an important contribution to national and global interpretations.
The kg CO2e CF value of rainbow trout harvested at approximately the same market size was found to be high in CPRT compared with inland water cage aquaculture (Diken et al. 2022; Table 9). Similarly, the value of 1.67 kg CO2e year−1 of CPRT CF expended, adapted to the APC, is higher than the value of cage rainbow trout reared in inland waters (Diken et al. 2022; Table 9). The CF values of Turkish CPRT are similar to the CF values of portion size (250–300 g) of rainbow trout farmed in France (Papatryphon et al. 2004). However, it is lower than the CF of flow-through rainbow trout farming in the same country (Aubin et al. 2009; Table 9). Rainbow trout have CF values according to the principle differences and different farming techniques (Table 9).
The CF value of CPRT is lower than that of 2.16 kg CO2e Atlantic salmon farming given in the Pelletier et al. (2009) report (Table 9). Ayer & Tyedmers (2009) and Pelletier & Tyedmers (2007) reported a 1.9–2.77 and 1.2–2.7 kg CO2e value per kg live weight gain of cultured Atlantic salmon, which is similar to our study results. This result is similar to the fact that the salmon CF value produced in land-based closed containment water recirculating aquaculture systems is higher than that of open net-pen systems (Liu et al. 2016). However, the CF values of the rainbow trout rearing in the inland waters of Türkiye were lower than those of RAS and open-cage Atlantic salmon (Liu et al. 2016; Diken et al. 2022; Table 9).
In the life cycle analysis of fish farming systems, Hagos (2012) found that the CF of the cobia cage farm is higher than that of the Asian sea bass recirculation farm. Hagos (2012) calculated these values as 8 kg CO2e kg−1 fish output for cobia cage farm CF and 1.7 kg CO2e kg−1 fish output for Asian sea bass recirculation farm CF (Table 9). On the other hand, the 1.64–2.00 (1.67, APC) kg CO2e CF value given in Table 5 was similar to the striped catfish culture system, while the values of carp culture and Nile tilapia (Robb et al. 2017) were higher than the composite fish culture, shrimp culture, seabass (Srinivasa Rao et al. 2016), and shrimp in the pond (Kauffman et al. 2018). Moreover, da Silva Pires et al. (2022) emphasized that the climate warming potential of aquaculture operations in terms of kg CO2e is greatly influenced by the selected aquaculture methods and species. The reason for this depends on the species and aquaculture system differences of aquaculture. Cultivation of rainbow trout, a carnivorous species, in intensive concrete ponds reveals species and system differences.
Besides being the primary producer of macroalgae, the bivalves are fed with natural foods, so there are no feed emissions and therefore their CF is low (MacLeod et al. 2020; Jones et al. 2022). The CF budgets of such types consist of logistics resources based on investment and transportation. Freshwater fish such as carp, catfish, and tilapia are omnivorous or herbivorous and require low levels of protein and fish meal due to their nutritional characteristics, and breed easily, and are tolerant to oxygen and nutrient wastes, and are farmed with low-cost technologies (MacLeod et al. 2020). Therefore, the CF, and the effects of climate change, may be low (Table 9). On the other hand, the most important factors in CF calculations are the CF of compound diets, which consists of nutritional needs based on species differences and feed ingredients, and the CF of feed consumption based on FCR (Henriksson et al. 2015; Diken 2022; Diken et al. 2022). Therefore, for the sustainability of aquaculture, feed safety based on feed ingredients is needed (Hognes et al. 2011; D'Abramo 2021). On the other hand, transportation and system differences that reveal the budget value of the investment and CF values of energy resources based on the aquaculture system, as well as the project capacity and the changing production amount of the project capacity over the years affect these calculations (Henriksson et al. 2015; Diken 2022; Diken et al. 2022). In these calculations, intensive production generally has a lower CF as it increases production efficiency (Lutz 2021). As in the results of the study, the decrease in CF values due to the increased production capacity is similar to the fact that the product obtained from rice-fish symbiosis systems has higher carbon emissions in small farms compared with large farms (Cui et al. 2020), and the CF of pangasius farming compared with large farms. The fact that it is higher in small-scale family companies (Henriksson et al. 2015) reveals the decreasing CF value in production due to increased production capacity.
As a result, the differences in the rearing systems are the main reasons for the similarities and differences between the CF results of rainbow trout and Atlantic salmon rearing (Table 9). If the use of feed ingredients based on similar carnivorous rations of these two species is ignored, the production of machinery and equipment used in land-based facilities and marine systems, and the structural value differences cause the difference in kg CO2e unit values, thus affecting the climate potentials of the facilities. As a result, in addition to the CF-based climate identities of rainbow trout and salmon species in the same family, the CF differences of species belonging to other families reveal the necessity of climatic identity species definitions based on the aquaculture system.
The inability of fish and crustacean species to produce CH4 through enteric fermentation, their direct secretion of ammonia, high reproductive ability and low FCR values, less energy requirement for locomotion, and cold-blooded vertebrates indicate that aquaculture species have a lower emission than ruminant monogastric species such as pigs and chickens (MacLeod et al. 2020). Additionally, globally, aquaculture has a much lower energy density than ruminant meat, while it has similar proportions to the main monogastric commodities (pig and broiler meat) (MacLeod et al. 2020). The CF expended for harvested fish was lower than for sheep, cattle, cows, pork/pig, poultry, and buffalo (Nemry et al. 2001; Rotz et al. 2010, 2019; MacLeod et al. 2020; Table 1). In addition, the effects of climate change on sectorial growth in ensuring food security of the aquaculture sector (Cubillo et al. 2021) have become an inevitable reality that will affect the CF of aquaculture. Reducing energy in feed production in aquaculture, improving FCR, increasing the variety of feed ingredients used, selecting species with high portion sizes, considering FCR, and practices that increase production efficiency will reduce CF values together with energy savings (Flos & Reig 2017).
CF for outputs
CF expended per kg carcass and fillet gained during feeding
The average CF expended for kg carcass and fillet gained during feeding 2.20 and 3.10 kg CO2e CF values, respectively in given Table 5 were similar to the 2–7 kg CO2e kg−1 meat CF of the aquacultured fish reported by Boyd (2013). The emission intensity of 2–4 kg (kg CO2e/carcass weight) of salmon aquaculture in the European region is more similar to the Eastern Europe emission intensity of 2.05 CF expended per kg marketed carcass value adapted to the project capacity of our study (MacLeod et al. 2020). Considering the regression analysis of these three-year production (TYP) values, the CF expended for kg carcass and fillet gained during feeding value of the APC was determined as 2.05 and 2.90 kg CO2e, respectively (Table 6). On the other hand, it was higher than the kg CO2e value of cage rainbow trout farming (Diken et al. 2022). It was determined that CF expended for kg carcass gained during feeding of CPRT was higher than cage rainbow trout farming. However, the ratio of the CF expended per kg marketed carcass to the CF expended per kg marketed fillet for cage rainbow trout farming and CPRT was similarly around 41% (Diken et al. 2022). The reason for this is the dressing percentage for carcass and fillet (81% vs 57.5%). The CF value of the total CF expended budget per kg of harvested fish, compared with the carcass and fillet ratios, increased by 23.4 and 73.8%, respectively (1.78 vs 2.20 vs 3.10).
CF expended per Mcal energy deposited in harvested fish gained, carcass, and fillet during feeding
The average CF expended per Mcal energy deposited in harvested fish gained during feeding was 0.92 kg CO2e (Table 5). These values increased by 89.7% and 167.2 compared with the carcass and fillet ratio of the harvested fish (0.92 vs 1.75 vs 2.46). Considering the regression analysis of these TYP values, the CF expended per Mcal energy deposited in harvested fish, carcass, and fillet gained during feeding value of the APC was determined as 0.85, 1.65, and 2.30 kg CO2e, respectively (Table 6).
CF expended per kg of protein deposited in harvested fish, carcass, and fillet gained during feeding
The average CF expended per kg of protein deposited in harvested fish gained during feeding was 10.66 kg CO2e (Table 5). These values increased by 14.8 and 61.7% compared with the carcass and fillet ratio of the harvested fish (10.66 vs 12.24 vs 17.24). Considering the regression analysis of these TYP values, the CF expended per kg of protein deposited in harvested fish, carcass, and fillet gained during feeding value of the APC was determined as 9.97, 11.45, and 16.10 kg CO2e, respectively (Table 6). While the protein increase rates of the CF were similar to the cage rainbow trout results (Diken et al. 2022), the energy increase rates were found to be low. This was because the total energy value of fingerlings stocked in cage farming is deducted from the total energy value of the harvested fish. The high protein retention efficiency for harvested fish, carcasses, and fillets in rainbow trout farming can be explained by the fact that rainbow trout is a good converter of feed protein to edible meat protein (Diken & Koknaroglu 2022; Diken et al. 2022). At the same time, since salmon produces twice as much protein as beef (MH 2017), the recovery of carcass and fillet waste products will support the sustainability of the blue economy in terms of CF.
CF expended per Mcal of cultural energy expended during production and cultural energy expended per Mcal of CF footprint expended during production
The average CF expended per Mcal of cultural energy expended during production was calculated as 0.36 kg CO2e (Table 5). In other words, kg CO2e was calculated for each 2.57 Mcal cultural energy expended during the production period. Considering the regression analysis of these TYP values, cultural energy expended per Mcal of CF expended during the production value of the APC was determined as 2.47 (Table 6). In cage rainbow trout farming, these values were determined as the average CF value of 0.35 kg CO2e per Mcal of cultural energy consumed during production and kg CO2e expended value for each 2.86 Mcal cultural energy expended during the production period, respectively (Diken et al. 2022). According to this evaluation which shows the relationship between carbon emission and cultural energy use depending on external energy (fossil fuel) input (Diken et al. 2022), it can be stated that rainbow trout cage farming was more sustainable than CPRT.
CF expended per 100 kcal food energy in harvested fish (kg CO2e)
The first, second, and third years and averages of our study indicate that the CF expended per 100 kcal food energy in harvested fish were 0.1415, 0.1212, 0.1162, and 0.1263 kg CO2e, respectively (Table 5). Considering the regression analysis of these TYP values, CF expended per 100 kcal food energy in harvested fish value of the APC was determined as 0.1173 (Table 6). Chang et al. (2017)'s CF analysis was the result of the shrimp farm life cycle assessment, while this study was the CF value per Mcal of cultural energy expended during production. When the kg CO2e kg−1 meat CF of the aquacultured fish and other farm animals as described in the report by Boyd (2013), and the carbon emissions related to producing various foods (kg CO2/100 kcal) as described in the report by Chang et al. (2017) were examined; the status of aquaculture is correlated with the results of our analysis of total CO2e expended (CF for per kg live weight gain or CF expended for per kg harvested fish) and CF expended per 100 kcal food energy in harvested fish. When the protein and calorie retention rates of aquatic and farm animals species by Fry et al. (2018) and the carbon emissions (kg CO2/100 kcal) associated with food production reported by Chang et al. (2017) were compared; it is seen that the species with high protein and calorie retention rates have low carbon emissions. When these reports (Chang et al. 2017; Fry et al. 2018; Boyd et al. 2020) and the results of the present study for the total CF expended, CF expended per Mcal of cultural energy expended during production, and CF expended per 100 kcal food energy in harvested fish were taken together, CPRT farming can be considered as sustainable production. In terms of the effects of climate change on sectorial growth in ensuring food safety in the aquaculture industry (Cubillo et al. 2021), it has become an inevitable reality that aquaculture will affect the CF.
In addition to the results given in the carbon budget, it is extremely important to determine the effects on food security based on the global climate crisis. I can recommend that this should be handled in two ways. Sustainable protein safety based on the climate identities of the crop, animal, and aquaculture production should be determined and discussed globally. It will determine the roadmaps in which these countries’ agricultural, animal and aquatic products will turn into policies and targets that will support their positive contributions to the world ecosystem. Secondly, the critical lines of the species within these production areas and the breeding systems of these species, namely the threshold lines, should be determined, regardless of which production areas of agricultural, animal, and aquatic products they have in the global sense. The establishment of a taxation system based on this will reach a level where sustainable food production will contribute to the sustainable world ecosystem. For example, after determining the threshold lines of food production of different aquaculture systems such as RAS, cage, and open-cage of rainbow trout, tax reductions should come for businesses with production values below the threshold line of this species’ rearing system with follow-up warning models. The climate identity labeling of the products should be handled within this framework. As a result, using less buried carbon resources will contribute to a sustainable world by reducing the pressures on the world's ecosystems and positively affecting the effects of the climate crisis. All these positive ethics also include attributes that are adaptive to the low CF circular economy definitions of aquaculture, which are very prone to circular economy models in which all the products obtained and product wastes are used.
CONCLUSION
Due to the decrease in the carbon footprint expended (CF, CO2e) value of the product obtained as a result of the increase in the production capacity in CPRT farming, the potential global warming impact has been reduced due to the reduction in fossil fuel use per product. In this case, production with the project capacity will positively affect climate change. In aquaculture farm management, it is important to obtain products with a high survival rate without wasting resources, for the protein value with low CF value in meeting the global food protein demand. In this respect, software programs such as Aqua Manager, which determine the CF values of the product obtained, should be evaluated within the farm management. Due to the effects of global warming and climate change, CF label values should become a necessity in the marketability of products globally and taxations based on CF values should also be regulated. In our world evolving toward a new order, this approach offers expansions to the paradigm of society 5.0 (effects of industrial nutrition) and industry 5.0 (artificial intelligence and software in terms of products, raw materials, and feed ingredients).
The results show that rainbow trout has a very important place in CF expended based on compound diet and compound diet. Therefore, in rainbow trout farming, alternative feed ingredients that do not affect the physiological development and FCR values of the rainbow trout and have low CF values (kg CO2e) should be emphasized. This analysis method, in which the direct and indirect effects of production steps in a farm are determined and monitored, shows that the CF values of the species (species-specific) and culture system (culture-specific) differences of aquaculture can be revealed on a national and global scale. The projections of sustainable food production should be presented by comparing the CF of fisheries species and aquaculture systems with the protein values of animal origin. With this approach, the results revealed that one of the carnivorous species, rainbow trout farming in concrete ponds is a sustainable industry. In line with the increasing food demands of aquaculture specific to the species and culture system due to anthropogenic climate change and global population growth, studies on the ‘sustainability of the blue economy’ that reveal the results of global food security are recommended.
ACKNOWLEDGEMENTS
The author would like to thank Dr. Hayati Koknaroglu, Dr. Hüseyin Sevgili, Dr. Joël Aubin, and Dr. Jacopo Bacenetti for their help during the study, and Fisheries Technician İsmail Can for fieldwork support.
DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.
CONFLICT OF INTEREST
The authors declare there is no conflict.
ETHICS APPROVAL
In this study, animals were not used.