Can Biological Traits Serve as Predictors for Fishes’ Introductions, Establishment, and Interactions? The Mediterranean Sea as a Case Study

Round 1

Reviewer 1 Report

General comments:

This is a very timely and interesting paper given that the topic of biological invasion has got increasing attention from diverse fields. Overall I found the paper to be excellent and the end results and conclusions are not surprising. I don’t confess to be an expert in the field of functional trait and biological invasion, but the approach is easy to understand and looks logical. The discussion is very good. Each time I thought of something that might be missing, it showed up a few sentences later. It is very thorough. Well done.

I suggest that this paper be published after the authors solve the following minor suggestions.

 

Some minor observations:

1) I suggest the authors upload their complete dataset as supplementary data. This information is important for readers who want to conduct further research in the future.

2) The abbreviations of NIS and NEO are a little confusing for me. Are the NIS and NEO two areas? Are there clearer words to describe this point?

3) I suggest the authors add a figure to describe the five study sites and the potential migration channels of invasive fishes. This figure will make readers clearer to the research background.

Author Response

Reviewer 1

The authors would like to thank the reviewer for his/her constructive review. Below responses to individual comments are provided.

 

 

1) I suggest the authors upload their complete dataset as supplementary data. This information is important for readers who want to conduct further research in the future.

We fully agree with the reviewer about the openness of data. Indeed, we have indicated in our cover letter that “All data used for the purposes of the analyses were extracted from FishBase (Froese & Pauly, 2021) and the specific dataset used could be made available upon request.”. The full dataset is in excel spreadsheets and should the reviewer/editor request it, we can provide it as supplementary material. Yet, as FishBase is constantly updated with new data/information, any reader/researcher that wants to conduct further research will have to update it.

 

2) The abbreviations of NIS and NEO are a little confusing for me. Are the NIS and NEO two areas? Are there clearer words to describe this point?

These abbreviations were used as suffixes of non-indigenous species (NIS) and neonatives (NEO). The former is widely used in the literature, whereas the latter is just a recent term. We hope that by adding the graphical abstract (see also comment #3) it will be easier for any reader to follow the text.

 

3) I suggest the authors add a figure to describe the five study sites and the potential migration channels of invasive fishes. This figure will make readers clearer to the research background.

We would like to thank the reviewer for this comment. We have added a map with migration channels as a graphical abstract

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript focus on biological traits as predictors for fishes’ establishment in the Mediterranean Sea. I think some questions need to be revised and corrected.

General comments：

1.This title needs to be revised. The center of the manuscript is not clear. The title is “Biological Characteristics Associated with fish habitat Establishment in the Mediterranean: The Role of Temperature, Habitat Type, and Body Length”, but the exposition about these three biological characteristics is only a small part of manuscript.

2.The highlight is that the biological traits of organisms in a certain region are not only analyzed, but also the biological traits of adjacent sea areas and invasive organis are analyzed and compared.

3.Materials and methods as well as discussion sections should be explained by subheadings to make the logic more clear .

Special comments：

4.Line 361: “In addition, Mediterranean Sea species also exhibit higher PD50 values (Phyloge- netic uniqueness, index of distinctiveness) compared to Red Sea and NIS species, and no difference with those of the Atlantic and NEO species.”

Interesting phenomenon, It deserves to be continued to discuss.

5.Line 368: “In general, Mediterranean fishes show few differences in traits with the Atlantic species, whereas differences in all traits between the Mediterranean and Red Sea fish fauna were observed.”

It is not appropriate that there are no differences between the Mediterranean and Altantic fish fauna. In 3.1 section of this manuscript, the species in the two regions are clearly different in important biological traits such as habitat type, mean temperature, etc.

6.The manuscript selects a variety of analysis methods, but some conclusions respectively obtained by these methods overlap. For example, chi-square tests for categorical variables are consistent with previous statistical descriptions of the biological traits of each region. The information reflected in the box-whisker plot can be fully obtained from Table 1.

7.Table 1 is suggested to be replaced by a more concise presentation.

8.Line 380: “Principal functional differences among species were associated with vulnerability, lifespan, k, resilience levels, Lmax, and preferred temperature.”

What's the basis for the conclusion? why not include habitat type?

9.Based on the results of principal component analysis, the overlapping degree of species traits space in different regions is discussed, but further discussion lack.

10.Line 402: “Based on the results of the analyses, demersal and pelagic species that prefer high temperatures are those from the Atlantic that are most likely to expand their range distribution in the Mediterranean.”

What is the basis for that judgment?

11.Line 414: “The Atlantic species, being on average dominated by carnivores, invade higher up in the Mediterranean food webs.”

What does the Atlantic specie mean, ATL or NEO species?

12.Line 455: “However, such an increase in fishing pressure will soon decrease the biomasses of local species to a threshold beyond which competition with NIS might possibly drive some of the local species to extinction. This will provide more space for both existing and other potential NIS (i.e., of the >1350 fish species inhabiting the Red Sea species to establish themselves.”

Won't the NIS species be caught?

13.The results of random forest can be combined with the analysis in the later section of P16.

Author Response

Reviewer 2

The authors would like to thank the reviewer for his/her constructive review. Below responses to individual comments are provided. Given the needs of the comments, an additional reference has been added, resulting in changes in the numbering.

 

 

General comments：

 

1.This title needs to be revised. The center of the manuscript is not clear. The title is “Biological Characteristics Associated with fish habitat Establishment in the Mediterranean: The Role of Temperature, Habitat Type, and Body Length”, but the exposition about these three biological characteristics is only a small part of manuscript.

The title has now been changed

 

 

2.The highlight is that the biological traits of organisms in a certain region are not only analyzed, but also the biological traits of adjacent sea areas and invasive organis are analyzed and compared.

This is true (see lines 71-74, introduction), and a small addition was been made in the abstract to depict this.

 

 

3.Materials and methods as well as discussion sections should be explained by subheadings to make the logic more clear .

Subheadings are now added, as suggested by the reviewer

 

 

 

Special comments：

 

4.Line 361: “In addition, Mediterranean Sea species also exhibit higher PD50 values (Phyloge- netic uniqueness, index of distinctiveness) compared to Red Sea and NIS species, and no difference with those of the Atlantic and NEO species.”

Interesting phenomenon, It deserves to be continued to discuss.

This is an excellent point, and we thank the reviewer. Relevant text has now been provided in the Discussion section

 

 

5.Line 368: “In general, Mediterranean fishes show few differences in traits with the Atlantic species, whereas differences in all traits between the Mediterranean and Red Sea fish fauna were observed.”

It is not appropriate that there are no differences between the Mediterranean and Altantic fish fauna. In 3.1 section of this manuscript, the species in the two regions are clearly different in important biological traits such as habitat type, mean temperature, etc.

We would like to thank the reviewer for this comment, the sentence was rephrased in order to be more clear.

 

 

 

6.The manuscript selects a variety of analysis methods, but some conclusions respectively obtained by these methods overlap. For example, chi-square tests for categorical variables are consistent with previous statistical descriptions of the biological traits of each region. The information reflected in the box-whisker plot can be fully obtained from Table 1.

This is indeed true, and they are all presented (as brief as possible) in order to strengthen the results obtained. In addition, and combined with comment #7, Tables 1 and 2 were moved in to the supplement section.

 

 

7.Table 1 is suggested to be replaced by a more concise presentation.

See reply in comment #6

 

 

8.Line 380: “Principal functional differences among species were associated with vulnerability, lifespan, k, resilience levels, Lmax, and preferred temperature.”

What's the basis for the conclusion? why not include habitat type?

We regret the omission. Text modified accordingly.

 

 

9.Based on the results of principal component analysis, the overlapping degree of species traits space in different regions is discussed, but further discussion lack.

It is not clear to us what the reviewer is requesting. Yet, we have made changes in the discussion (as also requested by the remaining comments) that hope to satisfy this comment too

 

 

10.Line 402: “Based on the results of the analyses, demersal and pelagic species that prefer high temperatures are those from the Atlantic that are most likely to expand their range distribution in the Mediterranean.”

What is the basis for that judgment?

This is mainly based on the profile of NEO species, ie those that enter in the Mediterranean and are of Atlantic origin. An explanation is added in the text

 

 

11.Line 414: “The Atlantic species, being on average dominated by carnivores, invade higher up in the Mediterranean food webs.”

What does the Atlantic specie mean, ATL or NEO species?

Thank you for pin-pointing this. It has been corrected

 

 

12.Line 455: “However, such an increase in fishing pressure will soon decrease the biomasses of local species to a threshold beyond which competition with NIS might possibly drive some of the local species to extinction. This will provide more space for both existing and other potential NIS (i.e., of the >1350 fish species inhabiting the Red Sea species to establish themselves.” Won't the NIS species be caught?

 

Yes, NIS will also be caught, but their resilience and vulnerability values indicated that the impact of fishing pressure on them will not be as high as the one on MED species. This part has been rephrased.

 

 

13.The results of random forest can be combined with the analysis in the later section of P16.

We thank you for the constructive comment. The text has been modified following this comment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I have no other comments. The manuscript can be published.

Author Response

We would like to thank the reviewer for having a second look on our manuscript. As no additional comments were made, we made no changes on the ms.