Evolution and Drivers of Embodied Energy in Intermediate and Final Fishery Trade Between China and Maritime Silk Road Countries

Abstract

Fishery plays an important role in world trade; however, the embodied energy associated with fishery remains incompletely quantified. In this study, we applied the multi-regional input-output (MRIO) model and logarithmic mean Divisia index (LMDI) approach to understand the evolution and drivers of embodied energy in the intermediate and final fishery trade between China and countries along the 21st century Maritime Silk Road (MSR) from 2006 to 2021. The findings are as follows: (1) Embodied energy in the intermediate fishery trade averaged 92.2% of embodied energy from the total fishery trade. China has gradually shifted from being a net exporter to a net importer of embodied energy in intermediate, final, and total fishery trade with countries along the MSR. (2) From a regional perspective, the embodied energy in China’s fishery trade with Japan, South Korea, and Southeast Asia comprises the majority of the embodied energy from China’s total fishery trade (82.0% on average annually). From a sectoral perspective, petroleum, chemical and non-metallic mineral products, and transport equipment were prominent in the embodied energy of China’s intermediate fishery trade (64.0% on average annually). (3) Economic output increases were the main contributors to the increasing embodied energy in all types of fishery trade in China. The improvement in energy efficiency effectively reduced the embodied energy in all types of fishery trade in China, but its negative driving force weakened in recent years owing to minor energy efficiency improvements. Understanding the embodied energy transactions behind the intermediate and final fishery trade with countries along the MSR can provide a theoretical reference for China to optimize its fishery trade strategy and save energy.

1. Introduction

Substantial economic growth in China has been accompanied by significant energy consumption and consequential environmental damage. China’s primary energy consumption reached 163.51 EJ in 2021, constituting 27.5% of global energy consumption [1]. Fossil fuel consumption leads to detrimental environmental impacts, such as the emission of environmental pollutants, including carbon oxides, sulfur oxides, and nitrogen oxides. For example, China’s carbon emissions account for nearly one-third of global carbon emissions [2], and almost 90% of China’s carbon emissions originate from energy consumption [3]. Saving energy and reducing carbon emissions have therefore become important challenges for China’s sustainable development. Indirect energy consumption caused by the supply chain is less commonly considered in energy consumption estimates than direct energy consumption. Indirect energy consumption in China accounts for more than 80% of the total consumption [4]. The sum of the direct and indirect energy required to produce goods and services is called embodied energy [5]. A large component of overall energy consumption results from embodied energy flow due to interregional trade. Embodied energy flow due to the global trading of goods and services exceeds 70% of the energy resources themselves [6]. Measurements and analyses of trade-embodied energy are essential for advancing sustainable development [7].

Fishery goods are among the most widely traded food products worldwide, with the fishery trade accounting for 10% of the global food trade [8]. According to the United Nations Comtrade Database [9], the value of China’s fishery trade has increased from USD 6.10 billion in 2002 to USD 41.97 billion in 2022, with its share in the global fishery trade rising from 5.7% to 9.3% over the same period (see Figure A1 in Appendix A). Countries along the 21st century Maritime Silk Road (MSR) are important fishery trade partners for China. Since the introduction of the Belt and Road Initiative, fishery trading between China and countries along the MSR has increased, with trading between countries accounting for more than one third of China’s total fishery trade. The fishery trade between China and countries along the MSR causes a high cross-country flow of embodied energy and therefore the transfer of environmental impacts. In addition, China and countries along the MSR are markedly different in terms of their energy resource endowments (see Figure A2 in Appendix A). The fishery trade may increase or decrease the pressure on energy resources and the related pollution emissions from energy consumption in these countries.

Embodied energy is an important component of embodied resource–environmental element flows [10] and has been shown to be a powerful tool for explaining energy consumption in product supply chains and engineering projects [11,12,13,14]. The extensive application of input–output analysis (IOA), especially the multi-regional input–output (MRIO) model and the compilation of MRIO tables, has promoted the study of trade-embodied energy and other resource–environmental elements from regional and sectoral perspectives [15,16]. Existing research into sectoral trade-embodied energy can be classified into multi-sector and single-sector areas. Research has tracked the embodied energy among various sectors at national and global levels [4,17,18]. For example, Liu et al. [4] used the IOA to measure embodied energy use across 29 sectors in China. Shi et al. [17] found that the key embodied energy flows, which accounted for only 0.02% of the total edges of the network, accounted for 80% of the network’s embodied energy. Existing single-sectoral trade-embodied energy studies have mostly focused on sectors such as construction [19,20,21], transportation [22], information and communication technology (ICT) [23], and agriculture [24]. For example, Liu et al. [20] revealed the indeterminacy and network characteristics of the embodied energy flow network of the global construction sector from a systemic perspective. Guo et al. [19] traced the embodied energy in the construction sector at the provincial level in China and at the national level globally based on nested input–output tables.

Based on embodied energy analyses, researchers have explored the drivers of embodied energy, mostly using structural decomposition analysis (SDA) or logarithmic mean Divisia index (LMDI) methods. Wang et al. [25] applied the spatial SDA method to study drivers of the net trade of embodied energy and virtual water between China and other major global economies. Their results showed that the production structure effect and export scale effect are the main factors contributing to China’s outflow of embodied energy and virtual water. Jiang et al. [26] measured drivers of embodied energy in the import and export trade of 39 countries using the LMDI approach, and showed that both energy intensity and economic output are major contributors to embodied energy flows in international trade. However, research on the drivers of embodied energy in the trade sector is lacking. Related research has mainly focused on direct energy consumption and carbon emissions, e.g., China’s energy consumption in the logistics sector [27], and carbon emissions from China’s construction sector [28], power sector [29], and the global ICT sector [30].

Although most existing studies analyze embodied energy use and its inter-industry and interregional flows, the studies generally focus on one aspect of intermediate, final, or total trade and lack a comparison of the embodied energy of intermediate and final trade. Increasing globalization and the fragmentation of global supply chains have increased the role of intermediate trade in world trade [31]. To compare the differences between intermediate and final trade patterns, research has focused on the analysis of global energy consumption [32], the structure of China’s trade-related carbon emissions [33], carbon emission imbalances in global supply chains [34], and global arable land use [35]. Some studies have demonstrated a large heterogeneity between the embodied energy in intermediate and final trade. Xia et al. [36] found that the embodied energy in intermediate trade contributes to approximately 80% of China’s international trade. Wu et al. [37] showed that China’s embodied energy from intermediate trade is close to five times that from final trade. Therefore, it is feasible and necessary to estimate sector-embodied energy and its drivers in terms of both intermediate and final trade patterns.

Embodied energy and other implicit resource–environmental elements related to fishery or the fishery trade have been briefly mentioned in existing studies [38,39,40]. Studies on resource–environmental elements based on fishery or fishery trade have focused on direct energy consumption in fisheries [41], carbon emissions and carbon neutrality [42,43], environmental footprints and carbon emissions from aquaculture [44,45,46], and the virtual water trade of aquatic products [47]. For example, Guzman-Luna et al. [44] measured the water, energy, and land footprints of tilapia in Mexico and found that tilapia had a much higher water footprint than other livestock, such as cattle, pigs, and poultry.

In summary, existing studies do not reveal the issue of embodied energy flows in international fishery trade, and the category of embodied energy trade in other sectors seldom distinguishes between intermediate and final trade. In view of this, this study takes the fishery trade between China and the countries along the MSR as an example and explores the evolution and driving factors of the embodied energy in the intermediate and final trade in fishery trade between China and the countries along the MSR, so as to enrich the perspective of the research on embodied energy in industrial trade and provide a reference path for energy savings in China’s fishery trade. Specifically, the main contents and contributions of this study are as follows: (1) We used the Eora MRIO table and MRIO model to analyze the regional and sectoral structures of embodied energy in the fishery trade between China and the countries along the MSR at the levels of intermediate and final trade. We propose suggestions for how China could realize energy savings in fishery by adjusting its trade structure. (2) We applied the LMDI approach to investigate key drivers of embodied energy in the intermediate and final fishery import and export trades between China and countries along the MSR. Knowledge of driving factors can provide China’s fishery industry with insights into energy conservation. (3) We discussed potential energy savings and embodied energy imbalances in the intermediate and final fishery trades between China and the countries along the MSR.

2. Material and Methods

2.1. Study Area

The MSR is an open and inclusive cooperation platform that does not have a clear geographic scope, but rather involves a wide range of countries [48]. In this study, we selected 44 countries involved in MSR–China trading, taking data availability into consideration. For analytical purposes, the 44 countries were divided into 7 regions (see

Table 1. Countries studied and aggregate regions in this study.

No.	Country	Abbreviation	Aggregate Region
1	China	CHN	China
2	Japan	JPN	Japan and South Korea
3	South Korea	KOR
4	Brunei	BRN	Southeast Asia
5	Cambodia	KHM
6	Indonesia	IDN
7	Malaysia	MYS
8	Myanmar	MMR
9	Philippines	PHL
10	Singapore	SGP
11	Thailand	THA
12	Vietnam	VNM
13	Bangladesh	BGD	South Asia
14	India	IND
15	Pakistan	PAK
16	Sri Lanka	LKA
17	Iran	IRN	West Asia
18	Iraq	IRQ
19	Kuwait	KWT
20	Lebanon	LBN
21	Oman	OMN
22	Qatar	QAT
23	Saudi Arabia	SAU
24	Turkey	TUR
25	United Arab Emirates	ARE
26	Yemen	YEM
27	Albania	ALB	Mediterranean Europe
28	Bosnia and Herzegovina	BIH
29	Croatia	HRV
30	Cyprus	CYP
31	Greece	GRC
32	Italy	ITA
33	Malta	MLT
34	Montenegro	MNE
35	Slovenia	SVN
36	Algeria	DZA	North and East Africa
37	Egypt	EGY
38	Kenya	KEN
39	Libya	LBY
40	Morocco	MAR
41	Mozambique	MOZ
42	South Africa	ZAF
43	Tunisia	TUN
44	Tanzania	TZA

).

2.2. Method

2.2.1. Multi-Regional Input–Output Model

The MRIO method traces the economic flow of production-driven intermediate trade and consumption-driven final trade. Resource–environmental element flows embodied in economic flows can be analyzed by attaching resource–environmental extension matrices to the MRIO table. The structure of the Eora MRIO table is presented in

Table 2. Structure of the Eora global multi-regional input–output table.

		Output	Intermediate Use							Final Demand			Total Output
			Region 1			…	Region n			Region 1	…	Region n
Input			1	…	n		1	…	n
Intermediate input	Region 1	1	$u_{ij}^{rs}$							$y_i^{rs}$			$x_i^r$
		…
		n
	…	…
	Region n	1
		…
		n
Value added			$v_i^r$
Total input			$x_i^r$
Energy use			$d_i^r$

.

The economic flow balance equation is expressed as follows:

$$x_i^r={\displaystyle \sum _{s=1}^m{\displaystyle \sum _{j=1}^n{u}_{ij}^{\mathrm{rs}}}}+{\displaystyle \sum _{s=1}^m{y}_i^{rs}}$$

(1)

where $x_i^r$ denotes the total output of sector i in region r, $u_{ij}^{\mathrm{rs}}=a_{ij}^{rs}{x}_j^s$ denotes the intermediate inputs in monetary form from sector i in region r to sector j in region s, $a_{ij}^{rs}$ denotes the direct consumption coefficient, and $y_i^{rs}$ is the final demand in region r driven by sector i in region s.

The material balance of energy utilization in the Eora MRIO table can be expressed as follows:

$$d_i^r+{\displaystyle \sum _{s=1}^m{\displaystyle \sum _{j=1}^n{\epsilon }_j^s}}{u}_{ji}^{sr}={\epsilon }_i^r{x}_i^r$$

(2)

where $d_i^r$ represents direct energy use in sector i in region r, and ${\epsilon }_j^s$ indicates the embodied energy intensity of sector j in region s, that is, the embodied energy consumption per unit of output in sector j in region s. From the perspective of energy use, some studies have shown that applying embodied energy intensity to intermediate trade can lead to double accounting [49]. But the embodied energy content of intermediate and final products is related to their production processes [36]. Therefore, this study applies embodied energy intensity to intermediate trade.

The matrix form of Equations (1) and (2) can be expressed as

$$\widehat{X}=U+\widehat{Y}$$

(3)

$$D+EU=E\widehat{X}$$

(4)

where ${\widehat{X}}_{mn\times mn}$ is the diagonal matrix of total output, $U_{mn\times mn}$ is the intermediate input matrix, ${\widehat{Y}}_{mn\times mn}$ is the diagonal matrix of final demand, $D={[d_i^r]}_{1\times mn}$ is the direct energy use matrix, and $E={[{\epsilon }_i^r]}_{1\times mn}$ is the embodied energy intensity matrix.

Based on the above quantitative relationships, the embodied energy intensity matrix E can be expressed as

$$E=D{\left(\widehat{X}-U\right)}^{-1}=e{(I-A)}^{-1}$$

(5)

where I is an identity matrix, A is the direct consumption coefficient matrix, matrix e denotes the direct energy intensity, and ${(I-A)}^{-1}$ is the Leontief inverse matrix, that is, the full demand coefficient matrix.

In this study, the intermediate fishery trade refers to the intermediate use of an economy’s fishery sector in the relevant sectors of other economies to satisfy the final demand for fishery. The final fishery trade refers to the final use provided by the fishery sector of one economy to other economies. Therefore, the embodied energy in China’s intermediate fishery exports and imports to countries along the MSR can be expressed as follows:

$$EI{E}^c={\displaystyle \sum _{r=1(r\ne c)}^m{\displaystyle \sum _{i=1}^n({\epsilon }_i^c}{u}_{if}^{cr})}$$

(6)

$$EI{I}^c={\displaystyle \sum _{r=1(r\ne c)}^m{\displaystyle \sum _{i=1}^n({\epsilon }_i^r}{u}_{if}^{rc})}$$

(7)

where $EI{E}^c$ is the embodied energy in China’s intermediate fishery exports, $EI{I}^c$ is the embodied energy in China’s intermediate fishery imports, $u_{if}^{cr}$ is the intermediate demand from the fishery sector in region r for each sector in China, and $u_{if}^{rc}$ is the intermediate demand from the fishery sector in China for each sector in region r.

The embodied energy in China’s final fishery exports and imports to countries along the MSR can be calculated as follows:

$$EF{E}^c={\displaystyle \sum _{r=1(r\ne c)}^m({\epsilon }_f^c}{y}_f^{cr})$$

(8)

$$EF{I}^c={\displaystyle \sum _{r=1(r\ne c)}^m({\epsilon }_f^r}{y}_f^{rc})$$

(9)

where $EF{E}^c$ is the embodied energy in China’s final fishery exports, $EF{I}^c$ is the embodied energy in China’s final fishery imports, $y_f^{cr}$ is the final demand from region r for China’s fishery sector, and $y_f^{rc}$ is the final demand from China for the fishery sector in region r.

2.2.2. LMDI Decomposition Method

The LMDI method enables a dynamic analysis of the evolution mechanisms of resource–environmental elements. Moreover, compared with the structural decomposition analysis (SDA) approach, the LMDI method has the advantages of relatively simple data processing and no residuals [50]. The LMDI is available in both additive form, suitable for quantitative analysis, and multiplicative forms, suitable for intensity analysis [51]. In this study, we used the additive LMDI method to decompose the drivers of embodied energy in China’s intermediate and final fishery imports and exports to countries along the MSR. The various types of embodied energy can be decomposed as follows:

$$EI{E}^c={\displaystyle \frac{EI{E}^c}{IT{F}_{ex}}}{\displaystyle \frac{IT{F}_{ex}}{GD{P}_f}}{\displaystyle \frac{GD{P}_f}{P_f}}{\displaystyle \frac{P_f}{P}}P$$

(10)

$$EI{I}^c={\displaystyle \frac{EI{I}^c}{IT{F}_{im}}}{\displaystyle \frac{IT{F}_{im}}{GD{P}_f}}{\displaystyle \frac{GD{P}_f}{P_f}}{\displaystyle \frac{P_f}{P}}P$$

(11)

$$EF{E}^c={\displaystyle \frac{EF{E}^c}{FT{F}_{ex}}}{\displaystyle \frac{FT{F}_{ex}}{GD{P}_f}}{\displaystyle \frac{GD{P}_f}{P_f}}{\displaystyle \frac{P_f}{P}}P$$

(12)

$$EF{I}^c={\displaystyle \frac{EF{I}^c}{FT{F}_{im}}}{\displaystyle \frac{FT{F}_{im}}{GD{P}_f}}{\displaystyle \frac{GD{P}_f}{P_f}}{\displaystyle \frac{P_f}{P}}P$$

(13)

where $IT{F}_{ex}$, $IT{F}_{im}$, $FT{F}_{ex}$, and $FT{F}_{im}$ are the monetary flows of China’s intermediate fishery exports, intermediate fishery imports, final fishery exports, and final fishery imports to countries along the MSR, respectively. $GD{P}_f$ is the GDP of China’s fishery sector, $P_f$ is China’s fishery population, and $P$ is China’s total population, to indicate the population scale effect. The right-hand sides of Equations (13)–(16) represent the drivers of the embodied energy in each type of fishery trade, where $EI{E}^c/IT{F}_{ex}$, $EI{I}^c/IT{F}_{im}$, $EF{E}^c/FT{F}_{ex}$, and $EF{I}^c/FT{F}_{im}$ are the embodied energy intensities of China’s intermediate fishery exports, intermediate fishery imports, final fishery exports, and final fishery imports, respectively. Specifically, $EI{E}^c/IT{F}_{ex}$ represents China’s sector-wide average embodied energy intensity, $EI{I}^c/IT{F}_{im}$ represents the sector-wide average embodied energy intensity of the countries along the MSR, $EF{E}^c/FT{F}_{ex}$ represents the embodied energy intensity of China’s fishery sector, and $EF{I}^c/FT{F}_{im}$ represents the average embodied energy intensity of the fishery sector of the countries along the MSR. $IT{F}_{ex}/GD{P}_f$, $IT{F}_{im}/GD{P}_f$, $FT{F}_{ex}/GD{P}_f$, and $FT{F}_{im}/GD{P}_f$ are the ratios of China’s intermediate fishery exports, intermediate fishery imports, final fishery exports, and final fishery imports to the GDP of China’s fishery sector, respectively, to indicate the dependence of China’s fishery sector on the various types of fishery trade with the countries along the MSR. $GD{P}_f/P_f$ and $P_f/P$ denote the economic output and population structure, respectively.

We take 0 to represent the base year and t to represent the target year. The impact of each driver on the embodied energy in each type of fishery trade can then be expressed as follows.

Energy intensity effect:

$$\Delta EI{E}_{{\displaystyle \frac{EI{E}^c}{IT{F}_{ex}}}}^c={\displaystyle \frac{EI{E}_t^c-EI{E}_0^c}{\ln EI{E}_t^c-\ln EI{E}_0^c}}\left[\ln \left({\displaystyle \frac{EI{E}_t^c}{IT{F}_{ext}}}\right)-\ln \left({\displaystyle \frac{EI{E}_0^c}{IT{F}_{ex0}}}\right)\right]$$

(14)

$$\Delta EI{I}_{{\displaystyle \frac{EI{I}^c}{IT{F}_{im}}}}^c={\displaystyle \frac{EI{I}_t^c-EI{I}_0^c}{\ln EI{I}_t^c-\ln EI{I}_0^c}}\left[\ln \left({\displaystyle \frac{EI{I}_t^c}{IT{F}_{imt}}}\right)-\ln \left({\displaystyle \frac{EI{I}_0^c}{IT{F}_{im0}}}\right)\right]$$

(15)

$$\Delta EF{E}_{{\displaystyle \frac{EF{E}^c}{FT{F}_{ex}}}}^c={\displaystyle \frac{EF{E}_t^c-EF{E}_0^c}{\ln EF{E}_t^c-\ln EF{E}_0^c}}\left[\ln \left({\displaystyle \frac{EF{E}_t^c}{FT{F}_{ext}}}\right)-\ln \left({\displaystyle \frac{EF{E}_0^c}{FT{F}_{ex0}}}\right)\right]$$

(16)

$$\Delta EF{I}_{{\displaystyle \frac{EF{I}^c}{FT{F}_{im}}}}^c={\displaystyle \frac{EF{I}_t^c-EF{I}_0^c}{\ln EF{I}_t^c-\ln EF{I}_0^c}}\left[\ln \left({\displaystyle \frac{EF{I}_t^c}{FT{F}_{imt}}}\right)-\ln \left({\displaystyle \frac{EF{I}_0^c}{FT{F}_{im0}}}\right)\right]$$

(17)

where $\Delta EI{E}_{{\displaystyle \frac{EI{E}^c}{IT{F}_{ex}}}}^c$, $\Delta EI{I}_{{\displaystyle \frac{EI{I}^c}{IT{F}_{im}}}}^c$, $\Delta EF{E}_{{\displaystyle \frac{EF{E}^c}{FT{F}_{ex}}}}^c$, and $\Delta EF{I}_{{\displaystyle \frac{EF{I}^c}{FT{F}_{im}}}}^c$ represent the energy intensity effects of intermediate fishery exports, intermediate fishery imports, final fishery exports, and final fishery imports, respectively.

Trade dependence effect:

$$\Delta EI{E}_{{\displaystyle \frac{IT{F}_{ex}}{GD{P}_f}}}^c={\displaystyle \frac{EI{E}_t^c-EI{E}_0^c}{\ln EI{E}_t^c-\ln EI{E}_0^c}}\left[\ln \left({\displaystyle \frac{IT{F}_{ext}}{GD{P}_{ft}}}\right)-\ln \left({\displaystyle \frac{IT{F}_{ex0}}{GD{P}_{f0}}}\right)\right]$$

(18)

$$\Delta EI{I}_{{\displaystyle \frac{IT{F}_{im}}{GD{P}_f}}}^c={\displaystyle \frac{EI{I}_t^c-EI{I}_0^c}{\ln EI{I}_t^c-\ln EI{I}_0^c}}\left[\ln \left({\displaystyle \frac{IT{F}_{imt}}{GD{P}_{ft}}}\right)-\ln \left({\displaystyle \frac{IT{F}_{im0}}{GD{P}_{f0}}}\right)\right]$$

(19)

$$\Delta EF{E}_{{\displaystyle \frac{FT{F}_{ex}}{GD{P}_f}}}^c={\displaystyle \frac{EF{E}_t^c-EF{E}_0^c}{\ln EF{E}_t^c-\ln EF{E}_0^c}}\left[\ln \left({\displaystyle \frac{FT{F}_{ext}}{GD{P}_{ft}}}\right)-\ln \left({\displaystyle \frac{FT{F}_{ex0}}{GD{P}_{f0}}}\right)\right]$$

(20)

$$\Delta EF{I}_{{\displaystyle \frac{FT{F}_{im}}{GD{P}_f}}}^c={\displaystyle \frac{EF{I}_t^c-EF{I}_0^c}{\ln EF{I}_t^c-\ln EF{I}_0^c}}\left[\ln \left({\displaystyle \frac{FT{F}_{imt}}{GD{P}_{ft}}}\right)-\ln \left({\displaystyle \frac{FT{F}_{im0}}{GD{P}_{f0}}}\right)\right]$$

(21)

where $\Delta EI{E}_{{\displaystyle \frac{IT{F}_{ex}}{GD{P}_f}}}^c$, $\Delta EI{I}_{{\displaystyle \frac{IT{F}_{im}}{GD{P}_f}}}^c$, $\Delta EF{E}_{{\displaystyle \frac{FT{F}_{ex}}{GD{P}_f}}}^c$, and $\Delta EF{I}_{{\displaystyle \frac{FT{F}_{im}}{GD{P}_f}}}^c$ represent the trade dependence effects of intermediate fishery exports, intermediate fishery imports, final fishery exports, and final fishery imports, respectively.

Economic output effect:

$$\Delta EI{E}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c={\displaystyle \frac{EI{E}_t^c-EI{E}_0^c}{\ln EI{E}_t^c-\ln EI{E}_0^c}}\left[\ln \left({\displaystyle \frac{GD{P}_{ft}}{P_{ft}}}\right)-\ln \left({\displaystyle \frac{GD{P}_{f0}}{P_{f0}}}\right)\right]$$

(22)

$$\Delta EI{I}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c={\displaystyle \frac{EI{I}_t^c-EI{I}_0^c}{\ln EI{I}_t^c-\ln EI{I}_0^c}}\left[\ln \left({\displaystyle \frac{GD{P}_{ft}}{P_{ft}}}\right)-\ln \left({\displaystyle \frac{GD{P}_{f0}}{P_{f0}}}\right)\right]$$

(23)

$$\Delta EF{E}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c={\displaystyle \frac{EF{E}_t^c-EF{E}_0^c}{\ln EF{E}_t^c-\ln EF{E}_0^c}}\left[\ln \left({\displaystyle \frac{GD{P}_{ft}}{P_{ft}}}\right)-\ln \left({\displaystyle \frac{GD{P}_{f0}}{P_{f0}}}\right)\right]$$

(24)

$$\Delta EF{I}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c={\displaystyle \frac{EF{I}_t^c-EF{I}_0^c}{\ln EF{I}_t^c-\ln EF{I}_0^c}}\left[\ln \left({\displaystyle \frac{GD{P}_{ft}}{P_{ft}}}\right)-\ln \left({\displaystyle \frac{GD{P}_{f0}}{P_{f0}}}\right)\right]$$

(25)

Population structure effect:

$$\Delta EI{E}_{{\displaystyle \frac{P_f}{P}}}^c={\displaystyle \frac{EI{E}_t^c-EI{E}_0^c}{\ln EI{E}_t^c-\ln EI{E}_0^c}}\left[\ln \left({\displaystyle \frac{P_{ft}}{P_t}}\right)-\ln \left({\displaystyle \frac{P_{f0}}{P_0}}\right)\right]$$

(26)

$$\Delta EI{I}_{{\displaystyle \frac{P_f}{P}}}^c={\displaystyle \frac{EI{I}_t^c-EI{I}_0^c}{\ln EI{I}_t^c-\ln EI{I}_0^c}}\left[\ln \left({\displaystyle \frac{P_{ft}}{P_t}}\right)-\ln \left({\displaystyle \frac{P_{f0}}{P_0}}\right)\right]$$

(27)

$$\Delta EF{E}_{{\displaystyle \frac{P_f}{P}}}^c={\displaystyle \frac{EF{E}_t^c-EF{E}_0^c}{\ln EF{E}_t^c-\ln EF{E}_0^c}}\left[\ln \left({\displaystyle \frac{P_{ft}}{P_t}}\right)-\ln \left({\displaystyle \frac{P_{f0}}{P_0}}\right)\right]$$

(28)

$$\Delta EF{I}_{{\displaystyle \frac{P_f}{P}}}^c={\displaystyle \frac{EF{I}_t^c-EF{I}_0^c}{\ln EF{I}_t^c-\ln EF{I}_0^c}}\left[\ln \left({\displaystyle \frac{P_{ft}}{P_t}}\right)-\ln \left({\displaystyle \frac{P_{f0}}{P_0}}\right)\right]$$

(29)

Population scale effect:

$$\Delta EI{E}_P^c={\displaystyle \frac{EI{E}_t^c-EI{E}_0^c}{\ln EI{E}_t^c-\ln EI{E}_0^c}}\left[\ln \left(P_t\right)-\ln \left(P_0\right)\right]$$

(30)

$$\Delta EI{I}_P^c={\displaystyle \frac{EI{I}_t^c-EI{I}_0^c}{\ln EI{I}_t^c-\ln EI{I}_0^c}}\left[\ln \left(P_t\right)-\ln \left(P_0\right)\right]$$

(31)

$$\Delta EF{E}_P^c={\displaystyle \frac{EF{E}_t^c-EF{E}_0^c}{\ln EF{E}_t^c-\ln EF{E}_0^c}}\left[\ln \left(P_t\right)-\ln \left(P_0\right)\right]$$

(32)

$$\Delta EF{I}_P^c={\displaystyle \frac{EF{I}_t^c-EF{I}_0^c}{\ln EF{I}_t^c-\ln EF{I}_0^c}}\left[\ln \left(P_t\right)-\ln \left(P_0\right)\right]$$

(33)

The changes in embodied energy in each type of fish trade from base year 0 to target year t can be calculated as follows:

$$\Delta EI{E}^c=EI{E}_t^c-EI{E}_0^c=\Delta EI{E}_{{\displaystyle \frac{EI{E}^c}{IT{F}_{ex}}}}^c+\Delta EI{E}_{{\displaystyle \frac{IT{F}_{ex}}{GD{P}_f}}}^c+\Delta EI{E}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c+\Delta EI{E}_{{\displaystyle \frac{P_f}{P}}}^c+\Delta EI{E}_P^c$$

(34)

$$\Delta EI{I}^c=EI{I}_t^c-EI{I}_0^c=\Delta EI{I}_{{\displaystyle \frac{EI{I}^c}{IT{F}_{im}}}}^c+\Delta EI{I}_{{\displaystyle \frac{IT{F}_{im}}{GD{P}_f}}}^c+\Delta EI{I}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c+\Delta EI{I}_{{\displaystyle \frac{P_f}{P}}}^c+\Delta EI{I}_P^c$$

(35)

$$\Delta EF{E}^c=EF{E}_t^c-EF{E}_0^c=\Delta EF{E}_{{\displaystyle \frac{EF{E}^c}{FT{F}_{ex}}}}^c+\Delta EF{E}_{{\displaystyle \frac{FT{F}_{ex}}{GD{P}_f}}}^c+\Delta EF{E}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c+\Delta EF{E}_{{\displaystyle \frac{P_f}{P}}}^c+\Delta EF{E}_P^c$$

(36)

$$\Delta EF{I}^c=EF{I}_t^c-EF{I}_0^c=\Delta EF{I}_{{\displaystyle \frac{EF{I}^c}{FT{F}_{im}}}}^c+\Delta EF{I}_{{\displaystyle \frac{FT{F}_{im}}{GD{P}_f}}}^c+\Delta EF{I}_{{\displaystyle \frac{GD{P}_f}{P_f}}}^c+\Delta EF{I}_{{\displaystyle \frac{P_f}{P}}}^c+\Delta EF{I}_P^c$$

(37)

2.3. Data Sources

The MRIO database is an important basis for calculating embodied resource–environmental elements. Currently available global MRIO databases include Eora, WIOD, EXIOBASE, OECD, and GATP. The Eora MRIO database covers 26 sectors in 189 economies globally, spanning 33 years (1990–2022), with corresponding environmental satellite accounts, such as water footprints, land use, and energy use [52,53]. The Eora MRIO table has been widely used in studies of embodied resource–environmental elements, such as water footprint [54], embodied land [55], embodied energy [56], and carbon footprint [34]. The Eora MRIO table is the only global MRIO table that fully covers the study area, and by considering the availability of other data, we were able to select the Eora MRIO table from 2006 to 2021. Eora MRIO tables and energy use data corresponding to each sector of each economy are available from the Eora Global Supply Chain Database [57]. In the Eora MRIO table, fishery corresponds to the International Standard Industrial Classification (ISIC) for capture, aquaculture, and services related to capture and aquaculture [53].

Since China’s fishery GDP data were not published from 2016, we instead considered China’s total fishery output data. Data on the total fishery output and fishery population were collected from the China Fishery Statistical Yearbook [58]. Data on the total fishery output value were deflated in Chinese Yuan at the constant 2006 price to enhance the comparability of the results of the study in different years. China’s total population data are available from the World Bank database [3]. It should be noted that we considered only mainland China and excluded Hong Kong, Macao, and Taiwan.

3. Results

3.1. Embodied Energy in China’s Foreign Fishery Trade

Figure 1 shows the evolution of embodied energy in China’s fishery trade with countries along the MSR from 2006 to 2021 and the proportion of each type of embodied energy in the total fishery trade. The evolution of embodied energy in China’s total, intermediate, and final fishery trades and the import and export trades with the countries along the MSR showed similar patterns (see Figure 1 and Figure 2), all showing fluctuations with an upward trend. During 2006–2021, the embodied energy in China’s total fishery trade and fishery imports increased by 6345 TJ and 6630 TJ, respectively, while the embodied energy in fishery exports declined by 284 TJ. Fishery imports contributed more to the growth of embodied energy in China’s total fishery trade than fishery exports.

Notably, China’s embodied energy in the total fishery trade showed two minimal values during the study period, in 2009 and in 2015. The minimal value in 2009 could be attributed to the economic crisis of 2008–2009. The reason for the minimal value in 2015 may be the increasing downward pressure on China’s economy in that year. In response, the Chinese government proposed supply side structural reform at the end of 2015, which was followed by a rapid increase in China’s embodied energy in the total fishery trade. From 2006 to 2021, China’s embodied energy in the intermediate fishery trade increased by 7953 TJ, while the embodied energy in the final fishery trade decreased by 1607 TJ. Embodied energy in the intermediate fishery trade was the major component (92.2% on average) of China’s fishery trade. In terms of net trade, China has gradually shifted from being a net exporter to a net importer of embodied energy in the intermediate, final, and total fishery trades with countries along the MSR (see Figure A3 in Appendix A).

3.2. Regional and Sectoral Characteristics of China’s Embodied Energy Trade

To analyze the heterogeneity between the intermediate and final fishery trades, we explored China’s embodied energy trade structures in fishery from a regional perspective (see Figure 3). The regions of Southeast Asia and Japan and South Korea were the main recipients of China’s intermediate fishery exports, accounting for 59.5% and 28.8% of the country’s’ intermediate fishery exports, respectively. Japan and South Korea, Southeast Asia, and West Asia were the major sources of China’s fishery intermediate imports of embodied energy, and the embodied energy in China’s fishery intermediate imports to the three accounted for on average 42.9%, 32.0%, and 18.5% of China’s total fishery intermediate trade, respectively. The regional flows of embodied energy in China’s final fishery trade are more concentrated than those in its intermediate fishery trade. Japan and South Korea were the main destinations for China’s final fishery exports of embodied energy in the regions along the MSR. On average, Japan and South Korea received 91.8% of embodied energy from China’s final fishery exports, while Southeast Asia received 7.5%. The combined share of the other four regions was less than 1%. Southeast Asia, Japan and South Korea, and North and East Africa were the main suppliers of China’s final fishery consumption, with China importing 55.1%, 27.8%, and 15.7% of its total energy from these countries, respectively.

Across the study period (2006–2021), the shares of South and Southeast Asia in China’s intermediate fishery exports of embodied energy increased by 3.0% and 4.0%, respectively, whereas those of Japan and Korea decreased by 5.9%. From 2006 to 2021, the share of each region in China’s intermediate fishery imports of embodied energy remained stable. Compared with the intermediate trade, there has been a greater change in the regional structure of embodied energy in China’s final fishery trade. Specifically, the shares of Japan and South Korea in China’s final fishery exports of embodied energy increased, while their shares in imports decreased. The shares of Southeast Asia in China’s final fishery exports decreased, whereas their shares in imports increased. The share of North and East Africa in China’s final fishery imports of embodied energy increased from 4.9% in 2006 to 9.9% in 2021, during which time North and East Africa became important sources of embodied energy in China’s fishery demand chain. Collectively, the embodied energy in China’s fishery trade with Japan, South Korea, and Southeast Asia dominates the embodied energy in China’s fishery trade with countries along the MSR (82.0% on average annually).

From a sectoral perspective, the most intermediate trade export embodied energy is provided to the fishery sector of countries along the MSR from China’s petroleum, chemical, and non-metallic mineral products (55.2%), transport (9.6%), transport equipment (8.8%), and textiles and wearing apparel (8.5%) (see Figure 4) industries. Of these, the shares of petroleum, chemical, and non-metallic mineral products and of transport showed a fluctuating upward trend from 2006 to 2021, whereas the shares of transport equipment and of textiles and wearing apparel showed a fluctuating downward trend.

China’s intermediate fishery imports received the most embodied energy from petroleum, chemical, and non-metallic mineral products (48.5%), transport equipment (14.0%), metal products (7.8%), agriculture (6.9%), transport (6.7%), and electrical and machinery (6.2%) in the countries along the MSR. The share of petroleum, chemical, and non-metallic mineral products in China’s intermediate fishery imports of embodied energy showed a fluctuating downward trend, whereas the shares of transport equipment, metal products, agriculture, transport, and electrical and machinery all showed a fluctuating upward trend. Taken together, petroleum, chemical, and non-metallic mineral products and transport equipment were prominent in China’s intermediate fishery trade of embodied energy (64.0% on average annually).

3.3. Drivers of Embodied Energy in China’s Foreign Fishery Trade

From 2006 to 2021, China’s intermediate fishery exports and imports of embodied energy to countries along the MSR increased by 2004 TJ and 5949 TJ, respectively. In contrast, China’s final fishery exports decreased by 3278 TJ, while final fishery imports increased by 817 TJ. The contributions of each driver to the embodied energy in China’s intermediate imports, intermediate exports, final imports, and final exports in fishery are presented in Figure 5, Figure 6, Figure 7 and Figure 8, respectively. Positive driver values indicate an increase in embodied energy, whereas negative values indicate a decrease.

Economic output effect was the key positive driver, increasing the embodied energy in China’s intermediate fishery exports (by 1806 TJ, 13.3%) and imports (by 2191 TJ, 13.4%) and final fishery exports (213 TJ, 12.9%) and imports (117 TJ, 13.4%) during 2006–2021. The per capita output value of China’s fishery population grew by CNY 207,005 during the study period, which consequently drove an increase in embodied energy in China’s intermediate fishery exports (by 27,090 TJ) and imports (by 32,859 TJ) and final fishery exports (by 32,010 TJ) and imports (by 1758 TJ).

Energy intensity effect was the predominant negative driver of embodied energy in China’s intermediate fishery exports and imports and final fishery exports and imports. Specifically, the reduction in the average sector-wide embodied energy intensity for China and countries along the MSR from 2006 to 2021 decreased China’s intermediate fishery exports (by 16,667 TJ, on average 8.1% per year) and intermediate fishery imports (by 13,440 TJ, on average 6.3% per year), respectively. The decrease in the embodied energy intensity of fisheries in China and countries along the MSR decreased China’s final fishery exports (by 2895 TJ, on average 7.4% per year) and final fishery imports (by 787 TJ, on average 6.9% per year), respectively. However, as the growth rate of energy efficiency slowed, the negative driving force of the energy intensity effect on the embodied energy in China’s fishery trade gradually reduced. For example, the embodied energy in China’s intermediate fishery exports decreased by 11,660 TJ from 2006 to 2010, owing to a reduction in China’s average sector-wide energy intensity. There was a smaller reduction of 355 TJ from 2018 to 2021, owing to the slow decline in energy intensity.

Heterogeneity exists in the impact of trade dependence on the embodied energy in China’s fishery trade. Specifically, all types of trade dependence effects showed relatively frequent positive and negative changes during the study period, resulting in both positive and negative calculated driving forces. The intermediate fishery export and import dependence effects were mainly negative drivers in 2008, 2011–2015, and 2018–2021; however, over the entire study period, both showed negative drivers, with average contributions of −1.6% and −2.2%, respectively. During 2006–2021, the final fishery export and import dependence effects were generally negative and positive drivers, respectively, with average contributions of −11.5% and 2.0%, respectively. The final fishery export dependency effect is another key negative driver of China’s final fishery exports of embodied energy, likely primarily due to the decrease in China’s fishery exports to countries along the MSR and significant reductions in the embodied energy intensity of China’s fisheries.

Population structure changes decreased China’s intermediate fishery exports (by 4811 TJ) and imports (by 5828 TJ) and final fishery exports (by 318 TJ) and imports (by 355 TJ) of embodied energy. With the gradual decline in China’s fishery population and the slow growth of China’s total population, population structure effects have the potential to reduce future energy consumption. The population scale effect increased China’s intermediate fishery exports (by 1007 TJ) and imports (by 1245 TJ) and final fishery exports (by 122 TJ) and imports (by 66 TJ) of embodied energy. The role of the population scale effect in increasing the embodied energy in China’s fishery trade will diminish further in the future due to a decrease in China’s population growth rate.

4. Discussion

4.1. Energy Savings in the Fishery Trade

Embodied resource savings may be achieved through the reallocation of resources through the global supply chain [21,47]. In this section, we discuss energy savings in the fishery trade between China and the countries along the MSR in terms of the domestic fishery supply chain and international trade. In particular, we compare whether the fishery import trade has a greater energy-saving effect if fishery demand is met by the domestic fishery supply chain instead of the fishery import trade. The calculation of the energy savings of the fishery trade and domestic fishery supply chain is presented in the Supplementary Materials.

From 2006 to 2021, China saved 69,395 TJ of its own energy use from intermediate fishery import trade with countries along the MSR (see

Table A2. Energy saving (TJ) for China and countries along the MSR in bilateral fishery trade and domestic fishery supply chain.

Years	China		Countries Along the MSR
	CIFI	CFFI	CIFE	CFFE
2006	9318	136	−6204	−990
2007	4305	−61	−1683	427
2008	6222	−134	−78	602
2009	4075	−168	2312	496
2010	5570	−200	3268	600
2011	6605	−216	3846	664
2012	6225	−245	3791	717
2013	3463	−317	4984	1118
2014	3724	−254	3915	1051
2015	2311	−288	4540	1033
2016	1202	−32	4686	1177
2017	4681	71	5311	985
2018	4208	94	4372	1038
2019	3026	118	4916	991
2020	2751	104	5068	1020
2021	1711	48	5776	1141
TEST	69,395	570	56,784	13,059
TESD	0	−1914	−7964	−990

Note: CIFI = China’s intermediate fishery imports; CFFI = China’s final fishery imports; CIFE = China’s intermediate fishery exports; CFFE = China’s final fishery exports; TEST = total embodied energy savings in trade; TESD = total embodied energy savings in domestic supply. Positive values represent energy savings in the fishery trade, and negative values represent energy savings in the domestic fishery supply chain.

in Appendix A); however, energy savings showed a downward annual trend. China’s energy savings from the final fishery import trade were much lower than those from the domestic fishery supply chain. Therefore, it would be more energy efficient to utilize the domestic fishery supply chain to meet China’s final fishery demand, provided that production conditions are available and domestic market resources are harmonized. From an economic perspective, China’s final fishery import trade promotes the economic development of related countries.

From 2006 to 2021, countries along the MSR avoided 56,784 and 13,059 TJ of their own energy use from China’s intermediate and final fishery export trade, respectively. Moreover, the energy savings gained by countries along the MSR generally exhibit an increasing annual trend. Although China imported and saved a large amount of embodied energy in the intermediate fishery import trade, these intermediate fishery products containing embodied energy were also delivered to countries along the MSR in the form of final or intermediate products processed in the next stage. In the process, the economic demands of countries along the MSR were met, and their energy savings were realized, contributing to a reduction in the pressure on energy resources in relevant low-energy-resource-endowment countries. This complementary fishery economy and embedded energy cycle are mutually beneficial for both China and the countries along the MSR.

4.2. Embodied Energy Trade Imbalances Behind the Fishery Trade

Section 3.2 presented differences in the embodied energy trade behind China’s fishery trade at the regional level. At the national level, each country along the MSR may play a different role in China’s fishery trade in terms of embodied energy. Indeed, imbalances in inter-regional embodied resource trade have become unavoidable due to production fragmentation and differences in resource endowments [59]. Figure 9 shows the intermediate and final fishery trade imbalances in embodied energy between China and its major partner countries along the MSR. The values represent the net imports of embodied energy from each country to China and the sphere size indicates the total embodied energy trade volume of fisheries from major partner countries to China. Over time, the regions showed an increased imbalance in intermediate trade and a decreased imbalance in final trade. In terms of embodied energy in the total fishery trade, Japan, South Korea, and Vietnam were China’s three largest trade partners in the MSR. From 2006 to 2021, Japan’s total trade volume decreased, whereas South Korea’s and Vietnam’s total trade volumes increased.

In terms of the intermediate net embodied energy trade in fishery, Japan, South Korea, Singapore, Thailand, the United Arab Emirates, South Africa, and the rest of the MSR were generally in surplus in their intermediate trade with China, and among these Japan’s surplus soared from 2006 to 2021. In contrast, Vietnam, India, Indonesia, and Malaysia were generally in deficit in intermediate trade with China, and Vietnam’s deficit showed a notable increase from 2006 to 2021. In terms of the final net embodied energy trade in fishery, Japan and South Korea had high deficits in their final trade with China. Vietnam and Thailand had a surplus in their final trade with China, and these two countries were the main sources of China’s net embodied energy imports for the final fishery demand.

In general, with the evolution of globalization and the decentralization and expansion of supply chains, the embodied energy imbalance in China’s final fishery trade is tending to ease. However, the embodied energy imbalance in China’s total fishery trade has remained severe owing to a serious intensification of the embodied energy imbalance in intermediate fishery trade. The trade imbalance in embodied energy indicates an optimal allocation of energy resources and a shift in energy pressure. For example, China imports large amounts of embodied energy through the fishery trade from energy-rich regions, such as the United Arab Emirates and Iran, thus partially optimizing the allocation of energy resources. In 2006, Japan net-imported large amounts of embodied energy from China through the final fishery trade, thus avoiding the consumption of its own energy resources and the related environmental impacts. As a result, China suffers from high energy consumption and the associated environmental pollution. This unfavorable situation was somewhat mitigated by improvements in technology and energy efficiency. Vietnam net-imported large amounts of embodied energy from China’s intermediate fishery trade, and China received some of the embodied energy from its final fishery trade with Vietnam. Hence, we suggest that adjusting fishery trade strategies with different countries is one way to save energy. Additionally, considering the economic benefits, improving energy efficiency remains an important path for China to realize energy-saving developments in fishery.

4.3. Comparisons with Previous Studies

With globalization and increasing imbalances between the supply of and demand for energy resources, trade-embodied energy has received much attention.

Table 3. Comparisons with previous studies on trade-embodied energy at regional and sectoral levels.

Type	Reference and Period	Focus	Method	Trade Pattern
Regional	Xia et al. [36]	China’s foreign trade	IOA	Intermediate trade
	1995–2018	Energy flows and drivers	SDA	Final trade
	Sun and Shi [63]	China’s foreign trade	IOA	Intermediate trade
	2002–2015	Energy flows and drivers	Gravity model	Final trade
	Lan et al. [60]	International trade	IOA	Final trade
	1990–2010	Drivers	SDA
	Jiang et al. [26]	International trade	IOA	Total trade
	1995–2011	Energy flows and drivers	LMDI
	Yan et al. [61]	China’s domestic trade	IOA	Final trade
	2012, 2015, 2017	Drivers	SDA
	Yang [62]	China’s foreign trade	IOA	Final trade
	1995–2015	Energy flows	Network analysis
Sectoral	Tang et al. [18]	All sectors	IOA	Intermediate trade
	2010	China’s domestic trade	Network analysis
		Energy flows
	Shi et al. [17]	All sectors	IOA	Intermediate trade
	1995–2009	International trade	Network analysis
		Energy flows
	Liu et al. [20]	Construction sector	IOA	Intermediate trade
	2000–2014	International trade	Network analysis
		Energy flows
	Liu et al. [21]	Construction sector	IOA	Intermediate trade
	1995–2009	International trade		Final trade
		Energy flows
	Li et al. [22]	Transportation sector	IOA	Intermediate trade
	2012	China’s domestic trade
		Energy flows
	Shi et al. [23]	ICT sector	IOA	Final trade
	2018	China’s domestic trade
		Energy flows
	Feng et al. [64]	Manufacturing sector	IOA	Intermediate trade
	2002, 2005, 2007, 2010, 2012	China’s domestic trade	Network analysis
		Energy flows
	This study	Fishery	IOA	Intermediate trade
	2006–2021	China’s foreign trade	LMDI	Final trade
		Energy flows and drivers

provides a summary of the previous literature and its comparison to this study. Trade-embodied energy at the regional level was extensively examined in terms of energy flows and their drivers, as well as differences in trade patterns. Relevant empirical studies at various regional scales found that improvements in energy efficiency significantly reduced embodied energy flows [26,60,61]. Similarly, our study shows the same conclusion even though our scale is precise to a specific sector (fishery) in a particular region (China and MSR countries). Globally, studies based on final trade found that China was a net exporter of embodied energy [62]. However, on the intermediate trade side, some studies found that China is a net importer of embodied energy globally and in the Belt and Road Initiative (BRI) region and that intermediate trade had greater potential for energy savings [36,63], which is similar to the findings of our study.

Differences in the regions, sectors, and time series studied may produce different findings. On the one hand, micro-scale studies can corroborate the adaptability of the findings of previous macro-scale studies to high-resolution regions and specific sectors, and on the other hand, the particular conclusions obtained may be more informative for the formulation of relevant policies. It is worth mentioning that our study takes into account higher-precision regional scales and sectoral types, more comprehensive trade patterns, and newer time series than previous studies, resulting in conclusions and recommendations with higher reliability and pertinence. For example, we reveal the impacts of fishery trade dependence and fishery population structure on China’s fishery embodied energy trade, which provides a theoretical reference for policymakers in formulating fishery trade strategies and population policies.

With regard to sector-specific trade-embodied energy, most existing studies explored the embodied energy flows between multiple sectors of global and domestic trade [17,18,23,64] or the interregional embodied energy flows of a specific sector (especially the construction) [20,21,22] from the perspectives of the volume, direction, and structure of flows. To better map embodied energy flows between sectors, some studies introduced the network analysis approach to the IOA framework. However, most studies only considered intermediate or final trade and did not sufficiently explore the heterogeneity of embodied energy flows in intermediate and final trade at the sectoral level. In addition, the impact mechanisms of sector-specific embodied energy flows were not sufficiently revealed.

By contrast, this study highlights the differences between intermediate and final trade in embodied energy at the sector-specific level and analyses the factors influencing intermediate and final imports and exports of embodied energy separately. Given the important share of fisheries in food trade, the influence of MSR countries in world fishery trade, and the prominence of intermediate trade in the global supply chain, our study reveals the embodied energy flows and their drivers in the intermediate and final trade of fisheries between China and MSR countries, enriching the content of sector-specific inter-regional embodied energy studies.

4.4. Limitations

Although the Eora MRIO database used in this study has good reliability [65] and its data errors are within acceptable limits, the data quality is poor compared to other MRIO databases such as EXIOBASE, GTAP, OECD, and WIOD [66]. However, the Eora MRIO database has the widest coverage area, which was an important reason for choosing it for this study. In addition, this study involves time series analyses of embodied energy in the fishery trade, but we did not deflate the Eora MRIO’s table for 2006–2021 at constant prices, which reduces the comparability of the study results in different years.

The LMDI method also has some limitations. Although the LMDI method offers advantages of aggregation consistency and complete decomposition, it ignores the influence of intermediate production structures. In contrast, although the SDA method has disadvantages of large calculations and residual errors, it can reflect the impact of intermediate production structure effects on embodied energy because the SDA method is based on input–output tables. Meanwhile, because it is constrained by input–output tables, the SDA method has fewer driver choices than the LMDI method. Therefore, a combined SDA–LMDI method, or a combination of one method with geographic or economic models, may be more appropriate for analyzing drivers of embodied energy [67].

Despite these limitations, we revealed the embodied energy flows in the fishery-production-driven intermediate trade and consumption-driven final trade, and we have therefore provided a new way of thinking about the study of embodied energy and other embodied resource elements in single-sector cross-border trade. Based on this study, future research could expand upon the content of embodied resource–environmental elements, such as by comprehensively analyzing the evolution of embodied energy, virtual water, virtual land, and embodied carbon in China’s foreign sectoral trade, and their interrelationships.

5. Conclusions and Policy Implications

5.1. Conclusions

Using the MRIO model, we calculated the embodied energy in China’s intermediate and final fishery trade with countries along the MSR and analyzed structural characteristics and evolutionary trends from regional and sectoral perspectives. We applied the LMDI method to explore driving factors of embodied energy in the intermediate and final fishery trade between China and countries along the MSR. The main conclusions of this study are as follows:

(1)

From 2006 to 2021, the evolutionary trends in embodied energy in the total fishery trade, fishery import and export trade, intermediate fishery trade, and final fishery trade between China and the countries along the MSR were generally similar, and all showed an increase with fluctuations. Embodied energy in the intermediate fishery trade was the major component (92.2%) of embodied energy in China’s fishery trade. China gradually changed from a net exporter to a net importer of embodied energy in intermediate, final, and total fishery trades with countries along the MSR.

(2)

From a regional perspective, the embodied energy in China’s fishery trade with Japan, South Korea, and Southeast Asia is the major part of the embodied energy in China’s fishery trade with countries along the MSR. Southeast Asia has gradually become the main region for China’s intermediate fishery exports and final fishery imports in terms of embodied energy. Japan and South Korea were major destinations for China’s final fishery exports in terms of embodied energy. Japan, South Korea, Southeast Asia, and West Asia were the leading sources of embodied energy in China’s intermediate fishery imports. From a sectoral perspective, petroleum, chemical, and non-metallic mineral products and transport equipment were the primary components (64.0%) of embodied energy in China’s intermediate fishery trade.

(3)

The results of the LMDI decomposition showed that economic growth was the major cause of increase in embodied energy in all types of fishery trade in China, and the positive driving force of the economic output effect gradually increased with time. Improvements in energy efficiency substantially reduced the embodied energy in all types of China’s fishery trade during the study period; however, as the improvement in energy efficiency slowed down, the negative driving force of the energy intensity effect gradually reduced. The trade effect showed a strong negative impact only on the embodied energy in China’s final fishery export trade and a weak impact on embodied energy in the remaining types of fishery trade. A decrease in the proportion of the Chinese fishery population had an inhibitory effect on the growth of embodied energy in all types of fishery trade in China. A decrease in population growth rate led to a decrease in the population effect on embodied energy in all types of fishery trade.

5.2. Policy Implications

Based on the findings of this study, we suggest that Chinese policymakers should attach great importance to embodied energy use in the fishery production chain. At regional and sectoral levels, China needs to consolidate its fishery production and trade cooperation with key regions such as Southeast Asia, Japan, and South Korea. Petroleum, chemical, and non-metallic mineral products and transport equipment had the highest embodied energy outflows in China’s intermediate fishery exports; thus, China should focus on improving the energy efficiency of these two sectors.

Improving sector-wide energy efficiency is also a necessary way to save energy in fisheries. For this purpose, China should increase investment in technology and capital to reduce sector-wide energy intensity and introduce and implement relevant energy efficiency standards to eliminate high-energy-consuming enterprises. Developed countries along the MSR, such as Japan and South Korea, obtained a large amount of embodied energy from the fishery consumption side. These countries should assume consumer responsibility and transfer part of the capital and technology to reduce China’s energy use and related environmental pollution.

In addition, China could contribute to promoting regional energy conservation in the fishery industry. For example, China could advocate for countries along the MSR to establish a fair and equitable environmental management system through the international platform of the Belt and Road Initiative. This could help to clarify each country’s responsibilities for energy saving and carbon reduction, and promote low energy consumption in fisheries in countries along the MSR.