Assessing the Importance of the Marine Chokepoint: Evidence from Tracking the Global Marine Traffic

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper presents an innovative application of AIS data, which has good potential for future economic analysis (also outside the specific subject of choke-points). Some suggestions for improvement are as follows:

p.6, last line: Asia-Pacific route is not from NW-Europe to east coast of North America.

p.7, 3rd line above 4.1.2: 'In 2019 etc. ' text seems to be in contradiction with the red line in Fig. 2b.

p.9, Fig. 4b: why not give numbers to the vertical axis?

p.11, l.6 below Fig.5: 'With the eastern borders encompassing the Bohai Sea and parts of the Yellow Sea, etc.'

         l.10 above 4.3.2: 'Similarity .... goods supply' --> Apparently the transport through Belgian ports has been allocated to the Netherlands. 

And delete 'a hub for foreign-owned distribution and logistic centers'. This gives an entirely wrong picture of the trade situation in the Netherlands and NW-European ports.

p.14, last line: 'Moreover the pursuit of ...... transport'--> this is the core of the issue. As long as alternate routes exist the influence of choke-points is relatively modest. Where these do not exist (e.g. the Bosphorus), the influence is large.

p.15, l.10 above Reference: 'Our analysis ..... patterns' --> I would suggest to write: 'Factors such as ...... influences contribute to the observed patterns'.

The maritime transport has now been treated as a whole. Analysing different trades, i.e. container traffic, liquid and dry bulk and general cargo may allow to derive more distinct results with respect to these influences.

Author Response

Dear Reviewer,

We sincerely appreciate your insightful comments and constructive feedback on our manuscript. Your expertise has been invaluable in enhancing the quality and rigor of our research. We have carefully considered each of your suggestions and made the necessary revisions to address the highlighted points.

In response to your guidance, we have refined the whole articles, please refer to the revised manuscript and response letter.

We would like to express our gratitude once again for your time and expertise in reviewing our manuscript. Your thorough evaluation has been pivotal in shaping the final version of our paper. We look forward to any additional guidance you may provide.

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

REVIEWER’S COMMENTS

Title of the article reviewed:

Assessing the importance of the marine chokepoint: Evidence from tracking the global marine traffic

Summary

This work uses the spatiotemporal data of the Automatic Identification System (AIS) and the method of Location Quotient to evaluate the importance of 15 critical chokepoints in global shipping and the dependence of countries on them, which has specific practical significance. But there are major problems that need to be modified. The article is poorly logical and readable. The article's content makes fewer references to sustainability-related content, which is not consistent with the scope of the journal. It is recommended that the logic be enhanced and clearly stated the internal logic between the article and sustainability. The authors should be careful with the grammar of the statements. There are given below.

Major Issues

Abstract:

·       At the end of the abstract section, the authors should add some specific information about their research results.

Introduction:

·       The introduction lacks an elaboration of the research question. It is recommended that the description of the research problem in the abstract could be more succinct.

·       The introduction should demonstrate the innovations and contributions of the paper.

·       It is recommended to add the implications of this study for sustainable development, such as the author's proposal for "sustainable national maritime security".

·       The current application fields and coverage areas should be provided.

Literature review:

·       The description of each literature in the literature review section should be shorter and refined.

·       The literature review should be summarised and analysed.

·       The first paragraph discusses "the impact of shipping routes and critical sea areas on optimising shipping processes", but this is not reflected in the literature review.

·       The literature review part is only a simple listing of the literature, and the logic is not strong, and it fails to clearly lead to the inheritance and innovation of the existing research. The literature review should reflect the shortcomings of the existing research and the differences between this paper and the existing research.

Data and methodology:

·       It is recommended that Figure 1 be improved for clarity.

Empirical results:

·       When presenting and analysing the graphs, it should reflect which graph is being analysed. In section 4.1.2, the author tries to use "(4b)" to refer to "Figure 4(b)", which should be clearly labelled. It is recommended to adjust for similar issues.

·       In section 4.1.1, the author suggests that "The actual footprint of shipping routes, while slightly shifted along the spatial paths of shipping routes compared to the official traditional route maps…". Additional references are suggested here.。

·       In section 4.1.2, the authors provide a forecast of marine traffic for 2012-2022. It is recommended to provide a basis.

·       In section 4.4, it is recommended to focus more on discussing the findings. Policy implications are more appropriately placed in the Conclusions

Conclusions:

·       In this section, the contribution of this paper should be condensed.

·       The conclusion should briefly mention the significance of this research and what kind of help it can provide.

Other issues:

·       The article has more problems with grammatical and punctuation errors. Check the English presentation of this paper to remove the typos and mistakes.

·       It is recommended to strengthen the essay's logic, such as between chapters and sentences.

General Comments

Finally, I hereby suggest rejecting this paper, but encourage the author to make changes to the above comments.

 

Author Response

Dear Reviewer,

We sincerely appreciate your insightful comments and constructive feedback on our manuscript. Your expertise has been invaluable in enhancing the quality and rigor of our research. We have carefully considered each of your suggestions and made the necessary revisions to address the highlighted points.

In response to your guidance, we have refined the whole articles, please refer to the revised manuscript and response letter.

We would like to express our gratitude once again for your time and expertise in reviewing our manuscript. Your thorough evaluation has been pivotal in shaping the final version of our paper. We look forward to any additional guidance you may provide.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

 

This article deals with an original issue and produces some very interesting results for the analysis of international maritime flows and their geopolitical and economic implications.

Overall, in terms of form, and as far as my English abilities allow me to assess it, it is well written, well structured and well argumented. It makes relevant use of the literature presented.

However, in detail I'm not convinced by the introduction, which lists generalities that aren't very well connected, particularly because they mix up the scales (international and national). Why not start the article with the second paragraph?

The literature review also needs to be revised, as the ideas are not always well connected. In particular, it contains incomplete sentences: "influencing factors" at the end of the 3rd paragraph; last sentence of the 4th paragraph.

The figures are generally well presented. Figure 3, however, deserves to be improved: it is very complex, with a large number of very small vignettes, and the map backgrounds interfere too much with the thematic information, which is not always clearly visible

In figure 4b, the legend does not correspond to the elements in the diagram (some symbols of the legend are not visible on the diagrams : Mean Different range of traffic flow). The titles of figures 4a and 4b seems to be inverted.

In figures 6 to 10, it would be interesting to position each chokepoint on the corresponding map, for easier reading and understanding.

 

In fact, my main criticism concerns the methodological approach and its description. Although the idea of using the Location Quotient model seems very interesting, the use of AIS data for a diachronic analysis seems to me to have a major bias. The study analyses trends in global maritime traffic from 2012 to 2022 using data from exactEarth Ltd. However, the period under consideration is also the one during which exactEarth, like its competitors, deployed their satellite constellations to complete the spatial coverage of maritime space and receive signals emitted by all ships, particularly offshore. As this deployment has been gradual, it is quite likely that the changes observed reflect as much, if not more, the improvement in the information received than the increase in maritime traffic, particularly in areas far from shore reception stations. This essential point is not discussed or even mentioned in the article. However, in the opinion of several data providers that I myself had the opportunity to consult prior to the acquisition of a Sat-AIS dataset (exactEarth, Spire and Orbcom in 2020), the evolution of the satellite constellation does indeed influence the exhaustiveness of the coverage of maritime space, and therefore the quality of the datasets produced.

Although my editorial comments would require only minor corrections, this significant methodological bias requires, in my opinion, a major revision of the proposed article.

Author Response

Dear Reviewer,

We sincerely appreciate your insightful comments and constructive feedback on our manuscript. Your expertise has been invaluable in enhancing the quality and rigor of our research. We have carefully considered each of your suggestions and made the necessary revisions to address the highlighted points.

In response to your guidance, we have refined the whole articles, please refer to the revised manuscript and response letter.

We would like to express our gratitude once again for your time and expertise in reviewing our manuscript. Your thorough evaluation has been pivotal in shaping the final version of our paper. We look forward to any additional guidance you may provide.

 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

  

REVIEWER’S COMMENTS

Title of the article reviewed:

Assessing the importance of the marine chokepoint: Evidence from tracking the global marine traffic

Summary

This work uses the spatiotemporal data of the Automatic Identification System (AIS) and the method of Location Quotient to evaluate the importance of 15 critical chokepoints in global shipping and the dependence of countries on them, which has specific practical significance. The article has been revised according to the comments of the reviewer. Clearly describe the relationship between the research issues and sustainability. However, there are still major problems that need to be modified. They are given below.

Major Issues

Introduction:

·       It is recommended to update the case. In the introduction, the article cites the 21 year Suez Canal crisis. Recently, the Suez Canal has been in crisis again. Cases are updated to ensure the novelty of the article.

Literature review:

·       The last paragraph of the literature review: the content after the second sentence is better placed at the end of the introduction. Present it as the research question posed by this study. This section should summarize the literature, including the several areas into which the existing research is divided, and which part of the gap is supplemented by the research in this paper.

Data and methodology:

·       The introduction of formula variables is not detailed enough. It is suggested to improve.

Other issues:

·       Check the English presentation of this paper to remove the typos and mistakes.

 

General Comments

Finally, I hereby recommend acceptance of this article after minor revision.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

I sincerely appreciate the time and effort you dedicated to reviewing my manuscript, titled "Assessing the importance of the marine chokepoint: Evidence from tracking the global marine traffic." Your constructive feedback has been invaluable in refining the quality of the paper. I have carefully considered each of your comments and suggestions, and I am grateful for the insights you provided.

Here are my responses and revisions based on your feedback:

1. Introduction:

1) It is recommended to update the case. In the introduction, the article cites the 21 year Suez Canal crisis. Recently, the Suez Canal has been in crisis again. Cases are updated to ensure the novelty of the article.

We greatly appreciate your correction. please refer to the revised manuscript P2L4 (also provided below).

“A notable instance is the "Suez Canal Crisis." According to Lloyd's Register, this canal, averaging between 205 to 223 meters in width, has witnessed almost 10 instances of vessel blockages in the past three years. The most recent incident occurred in June 2023 when the Maltese-flagged oil tanker "SEAVIGOUR" experienced a malfunction within the Suez Canal channel, fortunately resolved after causing a delay of several hours. However, not every occurrence concludes as smoothly. In March 2021, the Panama-flagged cargo ship "Ever Given," owned by Taiwan's Evergreen Marine Corporation, ran aground in the Suez Canal, resulting in a six-day blockade. Estimates by the Allianz Group suggest daily losses ranging from $6 to $10 billion due to the strait's obstruction.”

 

2) The last paragraph of the literature review: the content after the second sentence is better placed at the end of the introduction. Present it as the research question posed by this study.

I sincerely appreciate your valuable suggestions on the structure of the paper. I have taken into consideration the observation that the initial placement of the crucial research questions at the end of the literature review paragraph resulted in a disorganized content structure. Additionally, I acknowledge that the description of the problems the paper aims to address in the introduction was not sufficiently clear. In light of this, I have undertaken a revision of the second-to-last paragraph in the introduction to enhance its clarity and coherence. please refer to the revised manuscript P2L30 (also provided below).

“The pivotal role of maritime chokepoints in driving global maritime economic prosperity and fostering sustainable development in countries, both economically and politically, is evident. However, a nuanced interpretation of the strategic significance of different maritime chokepoints is essential. Is there a variation in the level of importance among distinct marine chokepoints? Furthermore, what is the extent of the impact of the unique characteristics of marine chokepoints on various geographical locations? Adopting a perspective of mutual interdependence, does a pronounced reliance of nations on particular marine chokepoints exist? To address these inquiries, this paper adopts a geographical perspective and utilizes spatiotemporal trajectory data of maritime vessels. Specifically, the study employs a dual perspective of supply and demand to identify key maritime regions and critical maritime chokepoints. Additionally, an innovative application of the Location Quotient (LQ) model is introduced to characterize the spatial impact of maritime chokepoints on a national scale.”

 

2. Literature review:

The last paragraph of the literature review: the content after the second sentence is better placed at the end of the introduction. Present it as the research question posed by this study. This section should summarize the literature, including the several areas into which the existing research is divided, and which part of the gap is supplemented by the research in this paper.

Thank you for your valuable suggestions on the logical structure of the literature review; we find them highly beneficial. We have comprehensively rewritten the final paragraph of the literature review, reinforcing the summary of current research and highlighting the innovative aspects of our study.

“In antecedent research, the safety and economic value of straits have been duly underscored. However, contemporary inquiries exhibit certain constraints. Previous research has often inclined towards a qualitative evaluation of the safety value of marine chokepoints or confined economic analyses to specific ones, thereby lacking an objective depiction of their strategic importance and a comprehensive global perspective. Given the rapid advancements in big data technology, a meticulous examination of marine chokepoints utilizing spatiotemporal vessel data has become of paramount significance. Consequently, by building upon the existing research framework, this study embraces a global perspective, fully harnessing the nuanced attributes of spatiotemporal vessel traffic data. The primary aim is to delineate global maritime patterns and discern the hierarchical characteristics of chokepoints, with the overarching objective of providing enhanced guidance for the development of global maritime strategies, the optimization of trade routes, and the safeguarding of international security.”

 

3. Data and methodology:

The introduction of formula variables is not detailed enough. It is suggested to improve.

Thank you very much for your valuable suggestions regarding the explanation of the formula variables in the paper. We have further interpreted and analyzed the relevant formulas to ensure that their content is clearer and more understandable.

“In this context, maritime dependence signifies a maritime nation's reliance on a specific strategic chokepoint. This reliance reflects the appeal of the chokepoint to the nation's maritime transport. It can be divided into demand-side marine traffic flow and supply-side marine traffic flow according to the differences in the import and export trade of each state. For a more comprehensive understanding of a chokepoint's maritime transport scope, the study employs the Location Quotient (LQ) model [24-25]., signifies a state's reliance on a specific chokepoint, computed through the formula:

 In Equation (1), where i represents the nation and j denotes the strategic chokepoint,denotes the maritime traffic flow of the ith nation through the jth strategic chokepoint,  represents the total maritime traffic flow of the ith nation, while  corresponds to the total maritime traffic flow through the jth strategic chokepoint, and  signifies the aggregate maritime traffic flow across all strategic chokepoints.

In essence, the equation calculates the ratio of a specific nation's maritime traffic through a particular chokepoint  to the total traffic through that chokepoint across all nations  This ratio is then normalized by the overall maritime traffic across all chokepoints and nations. A value greater than 1 indicates significant maritime dependence of nation i on chokepoint j, with higher values representing stronger dependence. Conversely, a  value less than 1 suggests lower maritime dependence.”

 

4. Other issues:

Check the English presentation of this paper to remove the typos and mistakes.

Thank you sincerely for your valuable suggestions regarding the adherence to writing standards in the article. Each sentence has been meticulously revised and refined to meet the criteria of clarity and precision.

 

 

Author Response File: Author Response.docx