Influencing Factors of Shellfish Consumption at the National Level

XiuHui Sun; Zifei Liu; Jun Li; Lintao Zhao; Zexi Yin; Shiwei Xu

doi:10.46989/001c.145767

1. Introduction

Under the dual pressures of escalating climate change and increasing natural resource constraints, the global food system is facing unprecedented challenges. The 2024 State of Food Security and Nutrition in the World report highlights that, in 2023, approximately 2.33 billion people worldwide faced moderate or severe food insecurity, and in 2022, over 2.8 billion people were unable to afford a healthy diet.¹ Promoting sustainable development in agriculture and fisheries, while improving resource use efficiency, is essential to ensure global food security.² Aquatic products have become an integral part of global food security, gaining increasing importance. This is due to growing awareness of their health benefits and the rising social preference for seafood. The scale of aquaculture is likely to expand in the future (Clark et al., 2019).³ Optimizing the international trade structure of aquatic products, strengthening fisheries resource management, and promoting green and healthy aquaculture practices will help better secure global food security. (Chen et al., 2023).⁴

Current studies generally agree that economic development, market maturity, technological advancements, and cultural backgrounds are key factors determining aquatic product consumption. (Lu et al., 2002; Hu & Wang, 2009; Yue et al., 2017; Tian et al., 2024).^5–8 From a national perspective, there are significant regional differences in aquatic product consumption. While accelerating urbanization, it is essential to consider the differentiated characteristics of aquatic product consumption across regions. (Zhang & Sun, 2009).⁹ At the global level, significant differences exist among countries in terms of consumption patterns, structures, and levels of aquatic products. These differences are not only related to income levels but are also influenced by market maturity and cultural factors. (Zhang et al., 2021).¹⁰ Understanding these differences is crucial for developing the aquatic economy and formulating relevant policies. (Zhang & Zhao, 2018).¹¹

As a high-nutrient and low-environmental-impact aquatic product, shellfish holds significant socio-economic and ecological value. From an industrial economics perspective, shellfish aquaculture has become a key sector driving employment growth, promoting rural economic development, optimizing dietary structures, and improving living standards (Que & Zhang, 2016).¹² In terms of sustainability, studies have shown that shellfish products are an important source of sustainable animal protein. Through innovative technological advancements in shellfish production models, traditional agricultural resource constraints can be overcome, providing marginalized groups in the global food security system with a sustainable protein source (Hallström et al., 2019; Willer & Aldridge, 2020).^13,14 Compared to land-based livestock farming, shellfish aquaculture offers significant advantages in carbon emissions (Ray et al., 2018; Ray et al., 2019; Jones et al., 2022),^15–17 making it an ideal choice for the transition to sustainable diets. In comparison to other aquatic products, shellfish provides a more environmentally friendly protein source. However, the resource potential of shellfish aquaculture remains underutilized, and its consumption remains marginal within the broader structure of aquatic product consumption. Therefore, how to leverage the unique advantages of shellfish to promote sustainable development while contributing to global food security and dietary nutrition is a critical issue that requires urgent attention.

Although the drivers of seafood consumption have been extensively explored in existing studies, research specific to shellfish consumption remains limited, particularly regarding the regional and national variations in shellfish consumption patterns. Given this, the aim of this study is to conduct a comparative analysis of apparent shellfish consumption in major producing countries, employing empirical research with a two-way fixed effects model. The study will investigate the mechanisms through which factors such as economic development, trade openness, demographic structures, and climate change influence shellfish consumption. Using major global shellfish-consuming countries as a sample, this study will explore the global and regional differences in shellfish consumption patterns, and propose policy recommendations for optimizing the shellfish industry within the context of global consumption structure upgrades and sustainable development. .

2. Research Methodology and Data Description

2.1. Variables and Research Hypotheses

From an industrial impact perspective, this study selects the top ten global shellfish-producing countries in 2022, using production volume as an indicator. The study examines the changes in overall shellfish consumption at the national level and conducts an empirical analysis on the factors influencing consumption in eight countries with relatively complete data. To more accurately reflect the shellfish consumption capacity and future potential of these countries, the study refers to the FAO Food and Nutrition Balance Sheets ,as well as the research by Li Xue et al. (2024)¹⁸ and Sun Xiuhui et al (2025),¹⁹ using per capita apparent consumption as the key indicator to compare and analyze the differences and changes in shellfish consumption across countries, which is then used as the dependent variable in the empirical study.

Based on consumer theory and demand elasticity theory, key variables such as household consumption capacity, consumption structure, and the shellfish substitute index are considered. Taking into account economic, social, consumer behavior, and environmental factors, this study integrates international trade theory, the life cycle hypothesis, and the Environmental Kuznets Curve theory, with reference to the works of Gao et al. (2013)²⁰ and Xiang & Zhong (2013),²¹ to include fisheries trade openness, population aging, and climate change as control variables in the analysis to ensure the robustness of the model results. (Shi et al., 2015; Huo et al., 2021; Ivanovich et al., 2022; Bianchi et al., 2022).^22–25

Based on existing literature and theoretical analysis, the following research hypotheses are proposed:

(1) Impact of Economic Development

Economic development level is a concentrated reflection of consumption capacity. Relevant studies generally align with economic theory, suggesting that economic development is conducive to increasing consumption, including shellfish consumption. (Cai et al., 2018).²⁶ This study uses per capita GDP as a proxy for economic development level. Additionally, considering that the conversion of consumption capacity into food expenditure is often constrained by the share of food expenditure in total consumption, this can be assessed through the Engel coefficient, an important indicator of household income levels and consumption structure. Theoretically, as economic development progresses, residents’ incomes increase, consumption levels rise, and the proportion of food expenditure in total consumption decreases, driving increased demand for higher-nutrient, higher-quality, and more diversified foods, such as shellfish.

Based on this, Hypothesis 1 and Hypothesis 2 are proposed:

Hypothesis 1: There is a positive correlation between per capita GDP and shellfish consumption.

Hypothesis 2: There is a negative correlation between the Engel coefficient and shellfish consumption.

(2) Impact of Substitutes

According to consumption theory, the price and quality of substitutes (in this study, other aquatic products excluding shellfish) can reduce shellfish consumption through substitution, price competition, and other factors. This study uses the shellfish substitute index as a proxy variable, specifically the ratio of non-shellfish aquatic product output to shellfish output, which reflects the level of competition between shellfish and other aquatic products. The higher the shellfish substitute index, the greater the competition pressure on shellfish in the market, which is unfavorable for shellfish consumption.

Based on this, Hypothesis 3 is proposed

Hypothesis 3: There is a negative correlation between the shellfish substitute index and shellfish consumption.

2.2. Model Specification

The following regression model is used to empirically analyze the determinants of per capita apparent shellfish consumption across countries. The general model equation is:

\[\begin{aligned}{SCC}_{it} = &\ \beta_{0}{{+ \beta}_{1}GDP}_{it} + {\beta_{2}Engel}_{it} + {\beta_{3}SSE}_{it} \\& + {\delta_{1}Trade}_{it} + \delta_{2}{Age}_{it} + \delta_{3}{Gas}_{it} + \gamma_{it} \\& + \lambda_{it} + \varepsilon_{it} \end{aligned}\tag{1}\]

Where:

${SCC}_{it}$：represents the per capita apparent consumption of shellfish in country 𝑖 at time 𝑡, which is calculated as shown in formula (2):

\[\begin{array}{r} SCC＝\frac{I_{shellfish} - E_{shellfish}＋P_{shellfish}}{pop} \end{array}\tag{2}\]

Here,$I_{shellfish}$，$E_{shellfish}$ and $P_{shellfish}$ refer to the import, export, and production volumes of shellfish, respectively; $SCC$represents the per capita apparent consumption, and $pop$ represents the population of the corresponding country or region.

${GDP}_{it}$：denotes the per capita GDP of country 𝑖 at time 𝑡;

${Engel}_{it}$is Engel’s coefficient for country 𝑖 at time 𝑡, which is calculated as shown in formula (3)

\[\begin{array}{r} Engel = \frac{E_{\ food\ }}{E_{\ total}\ } \end{array}\tag{3}\]

Where，$E_{\ food\ }$refers to the total expenditure on food, and $E_{\ total}$ refers to the total consumption expenditure.

${SSE}_{it}$：represents the shellfish substitute index for country 𝑖 at time 𝑡, calculated as shown in formula (4):

\[\begin{array}{r} SSE = \frac{P_{non - shellfish}}{P_{shellfish}} \end{array}\tag{4}\]

Where $P_{non - shellfish}\ $ refers to the production volume of non−shellfish aquatic products, and $P_{shellfish\ }$ refers to the production volume of shellfish；

${Trade}_{it}$：represents the fisheries trade openness for country i at time 𝑡, calculated as shown in formula (5):

\[\begin{array}{r} Trade = \frac{T_{water}}{P_{water}} \end{array}\tag{5}\]

Where $T_{water}$ refers to the trade volume of aquatic products, and $P_{water}$ refers to the production volume of aquatic products.

${Age}_{it}$ represents the degree of population aging for country 𝑖 at time 𝑡；
${Gas}_{it}$ refers to the greenhouse gas emissions of country 𝑖 at time 𝑡;
$\beta_{1}{,\beta}_{2}{,\beta}_{3}$represent the coefficients of the core explanatory variables, indicating the marginal effect of each independent variable on shellfish consumption. A positive value indicates a positive influence, while a negative value indicates a negative influence;
$\delta_{1},\delta_{2},\delta_{3}$represent the coefficients of the control variables;
$\gamma_{it}$ represents the country fixed effect, which controls for country-level invariant factors;
$\lambda_{it}$ represents the time fixed effect, controlling for global time trends;
$\varepsilon_{it}$ is the error term, representing the unexplained part of the model and reflecting other factors that may influence shellfish consumption.

The regression model includes year dummy variables, and the overall model is significant. However, as the coefficients of the year dummy variables have minimal impact on the conclusions of this study, their specific coefficients are not displayed in detail.

2.3. Data Description

Considering data availability, this study selects the period from 1976 to 2022 (a total of 47 years) as the timeframe for estimating per capita apparent shellfish consumption. The empirical analysis includes panel data from eight countries: China, Japan, the United States, South Korea, Spain, France, Canada, and New Zealand, with a total sample size of 376 observations.

Data on fishery and shellfish production, as well as import and export trade, were obtained from the Food and Agriculture Organization (FAO) Fisheries Statistics Software FishstatJ.²⁷ The shellfish production category includes species such as abalones, mussels, snails, clams, oysters, and cockles—bivalve mollusks in general. The data cover both aquaculture and capture production methods. Shellfish product processing types include live, fresh, chilled, smoked, salted, and dried forms. Population data, per capita GDP, and aging indicators for each country were sourced from the World Bank Group.^28–30 Greenhouse gas emissions data were retrieved from Our World in Data.³¹ The raw data required for calculating the Engel coefficient for each country were sourced from national statistical offices, specifically household or residential consumption expenditure data.

Given the differences in consumption expenditure reporting standards across countries, as well as the significant variations in the dimensionality of the variables, logarithmic transformations were applied to all non-index variables, and all variables were standardized prior to the empirical analysis. This ensured the practical relevance of the model and achieved comparability across different indicators. To handle missing values in the panel data, both forward and backward interpolation methods were employed. Specifically, forward interpolation was first applied, followed by backward interpolation to fill in any remaining missing values. This approach ensured both the smoothness and consistency of the data, while minimizing the impact of missing values on subsequent analyses. It is important to note that missing data was primarily concentrated in the Engel’s coefficient data for Spain, Japan, New Zealand, and Canada prior to the 21st century.

Table 1.Descriptive Statistics and Expected Signs for Major Variables

	Variable	Variable Meaning	N	Mean	Standard Deviation
Dependent Variable	SCC	Per capita apparent shellfish consumption (kg)	376	6.21	3.461
Independent Variables	GDP	Per capita GDP (USD)	376	22649.46	16122.98
	Engel	Engel coefficient（interpolated where applicable）	376	0.19	0.123
	Engel（raw）	Engel coefficient (raw, non-missing values only）	282	0.20	0.129
	SSE	Shellfish substitute index	376	6.72	3.494
Control Variables	Trade	Fisheries trade openness	376	0.74	0.611
	Age	Proportion of population aged 65 and above（%）	376	12.739	4.903
	Gas	Greenhouse gas emissions (Tonnes of CO₂ equivalents)	376	2041094199	2986743681

3. Results and discussion

3.1. Global Shellfish Consumption Status

Between 1976 and 2022, global per capita apparent shellfish consumption showed a continuous upward trend, rising from 0.74 kg per person to 2.40 kg per person, with an average annual compound growth rate of 2.53% (see Figure 1). Countries such as Chile, New Zealand, and South Korea exhibited significantly higher per capita consumption levels than the global average, reaching 18.75 kg per person, 12.84 kg per person, and 10.59 kg per person, respectively, in 2022. This phenomenon is closely tied to these countries’ well-established consumption habits and the widespread availability of shellfish in their markets (Lopez et al., 2008).³² For instance, New Zealand has a long-standing shellfish industry with a well-developed supply chain. The industry heavily relies on sustainable development models, leveraging advanced mechanized farming techniques and stringent marine environmental protection policies. As a result, New Zealand’s shellfish products are known for their high quality and are highly sought after in international markets.

From a global supply perspective, the total production of fisheries and aquaculture reached 223 million tons in 2022, with Asian countries contributing over 70% of the total (FAO, 2024).³³ China, as a central driver of this growth, is not only the largest producer but also the fastest-growing consumer. Between 1976 and 2022, its per capita consumption rose from 0.30 kg to 10.52 kg, with an annual compound growth rate of 7.9%. This remarkable leap is primarily attributed to breakthroughs in aquaculture techniques and seedling breeding technologies.

In contrast, traditional consumer countries like Japan, the United States, and Spain have experienced a long-term decline in per capita shellfish consumption. This trend can largely be attributed to factors such as the neglect of local species protection, water pollution, illegal fishing, and unfavorable economic conditions (MacKenzie, 2007; German et al., 2015; White, Ruesink, & Trimble, 2009).^34–36 For example, Japan’s per capita shellfish consumption peaked at 7.99 kg in 1990, but declined to 5.11 kg by 2022, a reduction of 36.3%. This decline is mainly due to overfishing, which led to the depletion of marine resources (Kyuji et al., 2005),³⁷ the aging population shrinking the consumer base (Ohtake et al., 1998),³⁸ and environmental crises such as the 2011 Fukushima nuclear disaster, which triggered a trust crisis in seafood consumption (International Atomic Energy Agency et al., 2011).³⁹

Figure 1.Per Capita Apparent Shellfish Consumption in Global and Major Shellfish Producing Countries from 1976 to 2022

Data Source: FAO FishStatJ, World Bank World Development Indicators Database

3.2. Cross-Country Indicator Analysis

(1) As shown in Figure 2, per capita GDP and apparent shellfish consumption exhibit generally similar trends across countries. However, in several developed economies—such as France, the United States, and Japan and Canada after the year 2000—an inverse trend emerges, with GDP increasing while shellfish consumption declines.