Evaluation of the Residency of Black Rockfish (Sebastes schlegelii) in Artificial Reef Areas Based on Stable Carbon Isotopes

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

First, the reviewer wants to thank the authors for their efforts. Although the presented manuscript presents an interesting approach to analyse the traceability and residency of Black Rockfish captured in Artificial Reefs (AR), it needs significant improvement to be published. The data and sources of data should be presented more objectively, and the manuscript can be more straightforward in the results presentation. One of reviewer’s main concern are the traceability conclusions based on a small sample size. Discussion need to be revised and better structured, since it was sometimes hard to follow the authors line of argumentation (below particular suggestions). I therefore recommend major revisions. I apologize if any of my comments are due to a lack of or mis-understanding on my end.

 

ABSTRACT

Abstract must be objective and focus on results. Most of the text in lines 22 to 27 justifies the study, and I suggest skipping most of it. English improvement is mandatory.

 

INTRODUCTION

Line 44-45: This sentence is incomplete and needs further in-depth, since you mention fish assemblages in the previous sentence and here you talk about restoration of fisheries.

Line 52-53: This sentence needs references.

Line 55-57: Improve English to clarify the idea. It is not production that is characterized, is the reef.

Line 57-64: The English is not clear. First you used the word “however” in the beginning of the sentence. It is the second time in this paragraph. You can delete it and just say: “Several researchers…”. Second, you use both and simultaneously in the same sentence. This is not well written. For example, rephrasing can be something like: “For instance, several pelagic fish species can temporarily prey and wander in these habitats due to the availability of food and the complex flow fields in the area, but they use other habitats to complete their life cycle, not contributing to the production function of artificial reefs.”

Line 66: Rephrase. Instead of use “whether the pre-deployment goals are met pre-deployment” you can say “if the purpose of using artificial reefs is achieved”.

Line 68-70: Rephrase. You use challenge 2 times.

Line 73: “the long-term site fidelity and continuous habitat utilization” of what? You need to add AR in the sentence. In fact, the whole paragraph does not mention if the studies are done or need to be done in AR.

Line 93-100: Improve English. For instance, if I understood it wright, you use black rockfish as a case study (and not as a target) to understand the relationship between attraction and production in AR. If this is wright you should say it. You must be clear to explain if your interest is to study the black rockfish ecology or the AR functions.

 

METHODS

Sample sites coordinates would be recommended.

Line 103-104: You don’t need the full stop and can continuing saying “(…) and covered three areas: AR area 1 (…)” or simple substitute the word “encompassed” by “covered”.

Line 113: From what the map shows there are more than three sampling sites. In fact, how will you compare the samples if they were collected in different sites in each season? The sampling seems highly random…

Line 118-119: Explain how the samples were preserved before processing in the laboratory.

Line 130-131: Incomplete sentence. Do you mean the composition of Rockfish diet?

Line 133-135: What does this mean? Is it a significant difference between zooplankton and rockfish or the diet of rockfish?

Line 135-143: This is very confusing, and you must change it. You mix sampling design and data analysis. I don’t understand what is the geographic isotopic season.

Line 150-151: This procedure is taken in account when using the correction Gelpi et al. method?

Line 167-172: This should be in the introduction, not in methods.

Line 173: Better explain what is the average natural tissue-based offset. I don’t understand.

Line 175: Why did you considered to 2% to be the limit if Fry et al (2003) suggest 1% and you mention this reference in the previous paragraph.

Line 184-186: How does a good adjustment of the linear regression (high R²) indicate residency?

 

RESULTS

Line 204-205: Body length results should be presented before carbon stable isotopic values since it characterizes the sample. I suggest to considerer to change the plots to put length in the x axis, to make it more intuitive.

Line 222-232: How do you explain the low correlation between δ13C values in the liver and muscle tissues? In methods you considered “Higher R2 values indicated a stable diet and higher residency, whereas lower R2 values indicated lower residency with additional diet sources.”

Line 246: Table 2 caption should be improved. Instead of “basic information” write “body length of black rockfish classified as non-resident”, which is what you are presenting.

Line 251: Erase “were”

Line 252-254: You must be clear and formal in presenting the results and avoid writing “offshore area > reef area > shore area”. Although I understood you are referring to the δ13C values in each area, it is not correct to describe results in this way.

Line 260: Clarify test results. Capital letters refers to ANOVA results between areas, but you don’t explain what different letters represent.

Line 269-271: This sentence is a conclusion/discussion on results. It should be in the discussion or, at least, after presenting results.

Line 271-271: This is on methods. You don’t need to repeat it.

Line 275-291: All this is very confusing. I don’t see the purpose of presenting these results since it is a very small sample, and no patterns can be detected. Also, the plots are not very easy to follow.

Line 285: English suggestion: “The δ13C values in the muscle of the three non-resident (…)”

 

DISCUSSION

Line 301-303: The goal was to determine if black rockfish captured in reef areas were resident or not. Your results don’t show differences between black rockfish captured in reef areas and control areas, and therefore, I have would be more caution in saying that stable carbon isotope technology successfully determine the origin of black rockfish.

Line 306-309: This is not accurate to say. First your sample is very small. Second, results show that only 50% of non-resident individuals had δ13C values in the muscle within the range of reef area, which in some cases is overlapped with inshore area. You also have only 1 non-resident fish that presented, in only one season, δ13C values in the liver within the range of inshore area.

Line 320-322: Clarify the sentence and Yu et al. results. I cannot understand what is said.

Line 323-336: This does not discuss paper results. This only led me to question what the purpose of the paper was if several authors already confirmed that AR are relevant for black rockfish.

Line 336-339: As I said previously, the paper does not determine the origins of non-resident individuals, and therefore this sentence is not wright considering the obtained results.

Line 352: Maybe you mean that it exceeded the length at which black rockfish are reported to mature. Correct accordingly.

Line 353-357: This should be rephrased since you lack a reference in the first sentence.

Line 359-361: In Summer the value of δ13C in the liver of Fish 1 is not within the range of any of the areas studied, and therefore your hypothesis is too much speculative. You should deliver more support, namely the releasing date or the growth rate. Also, I don’t understand the connection between this hypothesis and blooms of macroalgae and phytoplankton. Where do they occur?

Line 369: Is 92.6% a low resident rate?

Line 369-378: I do not follow the rational of this paragraph. You should have mentioned in results what is the length of fished sampled in each area. How can you just say that juveniles are no longer non-resident? This lacks consistency.

Line 381-383: In summer non-resident fish is juvenile, in autumn juvenile individuals were no longer identified as non-residents, and in winter both the non-resident individuals were juveniles. You explain these differences based on a very small sample which does even have inconsistent results in spring. You can't be so affirmative.

Line 401-409: I agree, and you should expand your explanation. Why is it uncertain? You start the following sentence with “Firstly” (you should use first and not use firstly), where you seem to question the criteria you used to define the non-resident fish. I don’t understand the rationale behind this explanation. You then start to talk about the independence between stable carbon isotopes and black rockfish body length. What does this have to do with the uncertainty of the method? All the paragraph is confusing.

Line 410-419: Precisely because these differences occur throughout the year I believe that with the samples you analysed (insufficient N) you cannot conclude anything about traceability. English language must be improved in all the paragraph but particularly in the last sentence because it is illegible.

Line 427-429: What do you mean by “concurrently sampling and treating the isotopes of zooplankton and rockfish to maintain similar environmental conditions”. The sampling design for fish was generally correct but for zooplankton was highly random.

Line 429-432: Why do you use the word additionally if you didn’t present any measure of nitrogen isotopes? You should have done it to derive conclusions.

Line 432-434: I must disagree. I didn’t observe any tendency. I also advise that these considerations are included at front, when discussing the results. Improve the English because “clear tendency for non-resident traceability” is illegible. What is traceability tendency?

Line 434: You start the sentence with “In addition” and we expect that you continue to argue about the use of stable carbon isotope technology in traceability studies. However, you talk about the use of acoustic telemetry to study fish movement and residence. It doesn’t make sense.

Line 451-459: Please explain the second reason why it is important. The rationale is not clear maybe because difficulties to explain it in English.

Line 460-466: Very confusing. First sentence talks about the potential of the study; second sentence about the effectiveness of stock enhancement; last sentence ends by affirming the relevance of combining approaches and mention modelling and climate change. I don’t understand which approach you mean and recommend you to better explain what you want to say.

Comments on the Quality of English Language

Throughout the text it was difficult to follow the authors English writing, and sometimes it resulted in lack of comprehension of the rationale. English improvement is mandatory, and I made several suggestions to improve it.

 

Author Response

Dear Reviewer,

Many thanks for your comments. We have provided detailed responses to each of your comment. Please see the attachment.

Best wishes!

Sincerely,

Authors

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In recent years, artificial reef (AR) construction has become an important way to restore the marine environment and fishery resources. Due to the lack of profound understanding of the function of AR ecosystem, many AR construction activities lack reasonable basis.

The manuscript provides interesting information for researchers working on the traceability and residency of reef-associated species. This is generally a well-written and convincing paper, and I think utilizing a stable isotope approach for this system is appropriate and interesting. The work is novel in that it compares isotopic values between liver and muscle tissues to determine residency and constructs an isoscape to explore the potential traceability of black rockfish. I recommend this article to be published in this journal after revision. The specific modification suggestions are as follows:    

 

Introduction: It covers a wide range of information for this study, but I suggest adding a sentence at the end of the last paragraph in Line 100 about the implication or importance of this work.

 

Line 78: “Black rockfish serve as a representative species for interpreting the ecological functions of Ars…” There should be added a reference to support.

 

Methods: Clear and detailed

The question about the experiment was the description of the ‘fish movement patterns’ (Line 129). Comparing isotopic values between zooplankton and fish tissues cannot clearly show the fish movement patterns and it is not related to this paper. I suggest rewriting the first sentence in this paragraph like “To investigate the potential traceability of the black rockfish, we constructed…”

 

Line 122: It is necessary to provide more information about why you did not select a fixed number of sites from different places, like inland, reef, or offshore areas. Is there some special design? Why?

 

Line 131: I suggest authors add a sentence to provide more information about why chose zooplankton to construct isoscape. For example, it may start as the zooplankton is at the bottom of the food chain with a lack of swimming ability that can represent the basic food sources.

 

Line 141: It is better to provide information about what software the author used to complete the interpolation. Is it in the R program?

 

Results

Section 3.2: "Spatial distribution of isoscape". The determination of isoscape has already shown the spatial variation in isotopic values. I suggest this heading and line 250 should be rewritten.

 

Table 3: There should be added the unit “‰” at the header or the caption of the table

 

Conclusion

Line 471: I still do not think we detected related contents about the ‘movement patterns’, maybe you can change the ‘movement pattern’ into ‘residency’ in that sentence.

 

Comments on the Quality of English Language

The text is well-written, with clear and concise language, and effectively conveys the intended meaning. The grammar and syntax are appropriate, and the usage of professional and technical terminology is accurate. However, there are a few instances where sentence structure could be improved for better clarity and flow. Overall, the writing is of a high standard and effectively communicates the ideas and findings presented in the manuscript.

Author Response

Dear Reviewer,

Many thanks for your comments. We have provided detailed responses to each of your comment. Please see the attachment.

Best wishes!

Sincerely,

Authors

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors performed a substantial improvement in the manuscript. However, one major concern remains to the reviewer. The method used to discriminate between resident and non-resident fishes, which is the core of the study, is not properly addressed. Authors employed an alternative method in the second version of the manuscript to describe residency. They have computed the Euclidean distance between data points but fail to present the thresholds of each category and the rational or reference that supports this method. Despite the improvement performed the reviewer recommends major revision due to the nature of the concerns. I apologize if any of my comments are due to a lack of or mis-understanding on my end.

Further comments below and suggestion in the pdf file.

Kind regards,

---------------

ABSTRACT

Line 23: You must clarify which local reef areas since only in line 25 you mention the study area.

Line 28: Maybe “consistent” is not the appropriate word. Consistent with what? With each other?

Line 28-31: If you present results with bullets 1) and 2), skip the full stop. Suggestion: “(…) with significant variations observed across seasons; 2) residency ratios of individuals (…)”.

 

INTRODUCTION

Line 38-42: Try to reduce these 3 sentences to one. There are several word repetitions: “fish assemblages” is used 3 times and “underlying” is used 2 times.

Line 52-54: Suggestion for English improvement “On the other hand, biocapacity in enhanced in reef habitats, since they provide sufficient food resources to the proliferation and growth of organisms, which contribute to the ‘production’ function.”

Line 55-55: Suggestion for English improvement “The contribution of ARs to both ‘attraction’ and ‘production’ ecological functions has been described in other studies”.

Line 86-89: Use the word “while” to connect sentences “(…) suggesting resident fish, while inconsistent δ13C values indicate (…)”

Line 94-99: This describes methods and don’t need to be in the introduction. I suggest the authors to erase it. Other suggestions to improve the paragraph in the pdf.

 

METHODS:

Coordinates can be in supplementary material, especially Table 2.

Line 193: move the formula to the end of the sentence.

Line 204-208: I don’t understand the criteria. How much is “Lower Euclidean distance” and “Higher Euclidean distance”? Which are the thresholds?

Line 209: Speculation is not a good word in a scientific paper since it means the forming of a theory or conjecture without firm evidence. Better not to say anything if no firm evidence can be presented.

 

RESULTS

Line 247-255: You need to clearly explain the criteria in methods to be able to present these results for residency.

Line 284-290: Table 5 caption explanations are still very confusing. You need to find a better way to explain the significant differences. Besides, to ensure that the ANOVA results are valid sample data should be from a normal population, or each sample should be > 15 or 20. I think you cannot use ANOVA to test differences between all factors (sites and season).

Line 295-320: The performed changes and author answers were clear but not convincing. Authors did not provide argumentation to sustain the relevance of results. I understand the purpose of the analysis but as I said before, the sample is very small and that’s probably the reason why no patterns can be detected.

 

DISCUSSION

Line 336-359: Discussion section purpose is to discuss the study results not to simple present findings from other studies without connecting them properly with the results obtained by the authors. This section should be improved and state more clearly what is the authors rationale and what was the increase knowledge about ARs produced by the study.

Line 382: Change “we speculate” to “possibly” or “likely”.

Line 400-402: Clarify the sentences. A temporary stay where? (Line 402). Editing suggestions in pdf.

Line 407: Change the word “speculate”.

Line 430: “remain consistent” with what? What the authors found was that there is no correlation between δ13C values and length…

Line 434: “The second concern is…” should begin the sentence considering the above. Rephrase.

Line 447: The same comment as previous. You should also indicate after the first sentence the factors enumerated in lines 452-454.

Line 452: Which studies? A reference is necessary.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

English can be improved. Several suggestions were made to improve it.

Author Response

Dear Reviewer,

Many thanks for your comments.

Please see our point-by-point response in the attached WORD file.

Best wishes!

Authors

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

Congratulations to the authors. The manuscript was greatly improved through the revision process and deserves publication.

Comments on the Quality of English Language

English Language deserves a final revision by an expert with proficiency in English. Some details/wording could be improved.