Abstract
This article examines the relationship between economic growth, international trade, and marine freight transportation. For this reason, annual data for marine transport and economic growth determinants is used, from 1978 to 2017 with the application of Auto Regressive Distributed Lag model to control the dynamics structure of the system in both growth and marine transportation models. Results indicate that an investment in the marine transportation sector causes economic growth and that marine transportation has a significant effect on international trade. Based on the results, it's proposed to increase marine transport facilities to improve trade balance.
 

INTRODUCTION

The dispersion of natural resources and the heterogeneity of the labor force and as a result the existence of comparative advantage in different countries prompt the countries of the world to mass produce the goods and services in which they have expertise to increase the welfare of their nation and surplus. They export their needs to other countries and in return import goods and services that do not have a comparative advantage in their production, and thus international trade has developed and its share in the world economy is increasing. Meanwhile, transportation plays an essential role and facilitates international trade. This industry is divided into four aspects: road, rail, sea, and air; with the expansion of various maritime activities and the increase in the volume of commercial exchanges between countries, the importance of transporting goods by ship has been revealed more than in the past, so that a large share of the added value of the transportation sector is related to the activities of moving goods through it is the sea. Therefore, it can be said that providing efficient services in sea transportation is one of the influential factors in the development of international trade and the main means of meeting the various needs of economic operators. Among other reasons for the value of sea transportation compared to other transportation issues, we can mention (the cheap price of transporting goods, the large volume and weight of goods, and the importance of shipping).
 

MATERIALS AND METHODS

Most of the data used were extracted and downloaded from the economic time series section of the Central
Bank, and the data related to non-oil exports were taken from the Trade Development Organization of Iran. In addition, the statistics related to sea transportation have been extracted from the statistical yearbooks of transportation. In time series models, economic variables are tried to be predicted and modeled only by using the information available in their past values ​​and the current and past values ​​of disturbance components. Structural models are multi-variable and try to explain the changes of one variable based on the changes of other variables. The model used in this article for the descriptive statistics of the research is the system of vector auto-regression equations. Before implementing this system, it is necessary to get information about the accumulation status of the variables and the accumulation of the whole system. As mentioned in the previous part, the main feature of accumulated series is that their mean, variance, and correlation coefficients do not remain constant over time and the effect of shocks on the variable will not remain constant over time.
 

RESULTS

Maritime transportation mainly affects the GDP and its growth through the change in trade volume. So, in the first equation, the effect of sea transportation on international trade and in the second equation, the effect of international trade on economic growth was examined. In examining the model related to estimating the impact of sea transportation on international trade and to examine the existence of a long-term relationship, Banerjee Dolado and Master's statistic was used, which is equal to 6.305. Considering that the marginal distribution of this statistic follows the T-Student distribution, compared to the critical values, at a significant level of 1%, we can confirm the existence of a long-term relationship in this equation.
 

DISCUSSION AND CONCLUSION

The raw outputs from the model estimates show that each one percent increase in the value of sea freight transportation will lead to an increase of 0.82 percent in international trade in the short term and 2.552 percent in the long term. The research findings show that with more than 99% confidence, the increase in trade will lead to an increase in the national gross product and then economic growth. Also, the increase in capital and the production of services in the maritime transport sector will increase international trade.