Larval Dispersal Modelling of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) from the Crab Banks along the Coast of Trang Province, Southern Thailand
, Phurich Boonsanit 1, Kattinat Sagulsawasdipan 2 and Suriyan Saramul 1,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsEnglish should be edited since many areas are not so clear. Some comments are embedded in the attached pdf file. There is no statistical analysis of the data where many tests could be conducted. For example, ANOVA could be used to compare the abundance of larvae before and after the release and between the different crab banks
Comments for author File: 
Comments.pdf
English should be edited since many areas are not so clear. Some comments are embedded in the attached pdf file.
Author Response
We would like to thank two anonymous reviewers for their valuable comments and suggestions. The authors agree with all suggestion and comments provided by the reviewers, and we believe that those suggestions could strengthen and improve our manuscript prior to publication. Therefore, we have corrected and added more details regarding the comments and suggestions assigned by the reviewers. In our revised version, all corrections and modifications are highlighted with yellow colour with the comments.
Reviewer I
English should be edited since many areas are not so clear. Some comments are embedded in the attached pdf file. There is no statistical analysis of the data where many tests could be conducted. For example, ANOVA could be used to compare the abundance of larvae before and after the release and between the different crab banks.
Answer: The authors would like to thank for valuable comments on our manuscript. In our revised version, we have revised many contexts and sections reading to comments and suggestions provided by both reviewers (please see our revised version). We have also sent our revised version for English proofreading, ensuring that English in our revised manuscript is suitable for scientific publication. Regarding your suggestions and comments in the attached PDF file, we have already corrected all points following your suggestions. For minor points suggested by the reviewer I, we have corrected all grammatical errors as suggested by your comments. For expressing the unit of zoeae, the zoeal abundance was calculated and reported in zoeal individuals per m3(see Line 279-280 ).
Reviewer 2 Report
Comments and Suggestions for AuthorsI have thoroughly reviewed the manuscript titled “Larval Dispersal Modelling of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) from the Crab Banks along the Coast of Trang Province, Southern Thailand”. Overall, I find the manuscript particularly interesting in the context of the analysis, given its focus on the monsoon period, an important marine resource, and relatively under-explored sites. The study holds considerable implication for conservation, especially in the realms of fisheries and seagrass meadows, and for contributing to ecological knowledge.
However, the content of the manuscript needs to go through major revisions to improve clarity, the coherence of the analysis and its relevance to existing knowledge gaps. As to date, the manuscript falls short to valorise the knowledge extractable from the model. I think the objectives of the study can be more ambitious than “understanding of the larval dispersal and recruitment”. You have a nice approach and results to suggest strategies based on marine connectivity for conservation of a marine resources in a context of extreme hydrodynamic variability due to the monsoon. The Methodology, as it is, lacks details for reproducibility. The Results is somewhat vague and miss the points that would align with the mns objectives and provide the reader with new information. The Discussion appears to be somewhat superficial.
I recommend that the authors refine the scientific writing of their research. Encouragement is provided to address all the comments outlined below for manuscript improvement.
Main Comments:
- The vocabulary should be accurate every time there is a risk of confusion. It was challenging to understand which transported objects were referred too (e.g., buoys, laboratory-reared larvae and virtual larvae).
- Your introduction should be reordered and modified. It is hard to follow the narrative line. a) Don’t blend fisheries and biology as you did in the initial paragraphs of your manuscript. This was my understanding of the current state of the introduction: L.28-31: General Biology, L.31-33: Economic activity. L.33-42: Reproductive ecology. L.42-50: Economic activity again. L.50-56: Conservation. L.56-59/60: Methodology (It should be removed from the introduction). L.60-65: Knowledge gap. L.66-87: Benefit of modelling. L.97-101: a melting pot of various information. L.101-105: Benefits of the study. b) I think you need to enhance the importance of the monsoon in the introduction. I am not familiar with this event and I don’t know if it is common to study its impact on dispersal studies like yours. d) State more specific objectives. Understanding the dispersal of a species is one thing you did, but in the results, there was a clear interest in the larval arrival over seagrass bed and on the monsoon event. You should articulate your objectives for this.
- Although I feel a scientific protocol in your methodology has been respected, you don’t provide enough details for the methodology to be trusted. a) Restructure the Methodology. The Paragraph 2.1. included laboratory details that should be provided in another section. More exactly, in the Paragraph 2.1., I would expect information on the hydrodynamics, monsoon and wind (maps and references included) on the study area. Paragraph 2.2 is messy. Improve clarity and clearly divide the text between: field/observation works and modelling. To sum up, structure your methodology in: study area, particle tracking modelling experience (hydrodynamic model description, particle transport model description and its set up, description of outputs analysis), laboratory/field experiments (collection of crabs, water tank conditions, larval release and sampling description, larval analysis), validation of models with buoy release (buoy type, release and tracking description) and larval sampling (description of analysis). b) Is the hydrodynamic model validated? Has the model been used in other studies? c) Clarify the timeframes of your study. When were female collected? When were laboratory-reared larvae released? When was the buoy released?
- Results should be reordered. a) First, talk about the general results on connectivity and dispersal around Table 2. b) Then, talk about the variability of larval spread with monsoon period through Figures 3,4,5. c) You should focus the description of your outputs on releavant seabed and/or sources. For example, at l.216-217, you stated that the larval transport was distinct accordingly to its source location but it was hardly supported with values. To illustrate your results for specific locations, I suggest to focus on a few relevant sources, either noticed from the results in Table 2, sources you mention in the Discussion because of their proximity to estuary, or because the dispersal patterns from these sources were interesting (see next sentence). I suggest to make a new table where the dispersal information is clearly visible for each sources (I provided more information in the technical comments).
- L.269: The whole section is challenging to understand. You mixed in so many information that I had trouble to associate the methodology with the results. I suggest to create two subsections to distinguish results from the pelagic sampling and megalopa collection experience
- a) Rewrite discussion for better comparison with published papers and cleared organisation of ideas per paragraph. Valorise your results and compare them to other studies, particularly emphasising the significance of monsoon influence. From what I read, I understood that: * First paragraph is about Coastal retention while passive. Discuss the importance of having the tides and a short pelagic life. * Second paragraph is about the importance of being transported to estuary. The idea is good but the text should be refined. * Third paragraph ia on the importance of the monsoon schedule in the larval transport. I think you had already good material in the current discussion, but it should be more valorised (is it one of the first studies with monsoon influence?) and compared to other studies. * Fourth paragraph is on the use of the discovery of crab connectivity to seagrass for conservation. * Fifth paragraph is to remind the model estimation aligned with real data. It needs a bit of improvement for clarity, but it was interesting. b) The discussion mention a new conservation action (releasing laboratory-reared larvae to key location that are favourable for connectivity) without defining and developing the idea properly. Develop and define this idea, addressing potential risks associated with this "seeding" method.
Technical comments
L.10: Clarify the scope of “well-known”. Is it specific to Thailand only? or widely studied worldwide? In Asian countries?
L.11-12: “while studies…not well-understood”. Make a transition from fisheries to the knowledge gap more explicitly. You shall make a statement about the general ecological knowledge of the crab, eventually emphisizing its importance for the fisheries.
L.12: Delete “here”.
L.14-15: For Delft3D-PART and afterwards, clearly stat that Delft3d-PART is the Lagrangian module of Delft3d, not the hydrodynamic model. Keep the name of that module for the main manuscript not the abstract. In the abstract, just state that you used a Particle transport model to simulate the larval dispersal. Also, explain briefly why you were interested in the monsoon event? It is needed to justify your interest for this.
L.17: “that the crab larvae significantly arrived along both…”
L.17: What do you mean by “upper and lower”?
L.18: You mention hydrodynamic factors, but in your manuscript and in your abstract, I did not know which one you are talking about. Be more specific.
L. 19: Tie “seasonality” to the "monsoon" feature. It is the backbone of your analysis, after all.
L.34-35: “are dominantly missing”
L.36: “ovigerous females release their carrying eggs” is confusing. Did you mean “The berried females releases their eggs”? Specify wether eggs hatched immediately or within a short time frame after their release. It is important information that should appear in the main text of the manuscript.
L.37: “eggs hatch and larvae moult through four zoeal stages until metamorphosing in one megalopa…” or something like this.
L.38: Provide information about the size of young crab.
L.44: “ Thailand contributes the fishery…” Please rewrite for clarity.
L.46: Provide the timeframe for the observed decrease in crab population
L.47-48: “which it probably has a significant threat” Do you mean “which probably causes a significant threat…”?
L.48: Delete “likewise”
L.49: what do you mean by “harvesting”? Harvesting is related to crop fields and not a suitable term.
L. 50: delete “key”
L.54: Provide the ID number and the hosting institution for the “crab Bank project”
L.55: “on a mission to protect and recover P. pelagicus populations/stocks to reach its sustainable exploitation and fishery management.”
L.56-59: This sounds like Methodology and it was a confusing text. About “carrying eggs”: see earlier technical comment. “after hatching for a day”, do you mean the incubation time was one day? Or did you wait one day before collecting larvae? I think these two sentences should be replace by specific concepts. In the next sentence, you refer to “enhancing restoration”. So, talk about active restorations facts which seed individuals (it is done with corals, for example).
L.63-65: Avoid the repeatiton from L.41-42.
L.66: Delete “In the present day”.
L.66-67: Please rewrite “a numerical model …hydrodynamic model” for clarity
L.68: “This result based on the model…” It is confusing and I don’t think it fits here.
L.72-74: Why these species? Why these studies? Nowadays, many studies exist on the larval transport. It is better to refer to general articles talking about larval transport concepts than giving examples that are not related to your study. It could have been interesting to mention studies of dispersal for P. pelagicus, for examples, or other species near your study area.
L.76: Instead of assuming no swimming activity for larvae, which is very unlikely, state that the passive larval transport relies solely on oceanography. It is quite acceptable to simulate passive particles if nothing is known on the larvae
L.78-79: Provide more relevant and specific information about larval traits, which should, somehow, be related to your text written below.
L.80: Delete: “As mentioned in a previous study”.
L.81: “based on laboratory and field observations”.
l.82: Where does 56% come from? Reference [16]? In that case, put the reference next to the number.
l.83: “over their development”
L.87: Delete “likely” + modify the sentence to “to set up biophysical models”
L.89: How many is in “there are many”? Can you provide an idea of the meadow coverage in your study area?
L.90: Specify the size for “*Large* seagrass meadows” and discuss their protection status, seagrass species compositions, and potential ecosystem services in a few words. More details can supplied in the section 2.1.
L.91-92: This is repetitive with previous texts.
L.93: Delete Here.
L.94: “approach with the Delft3D-Part model”
L.94-96: this should be move to methodology.
L.97: Delete period after “cm/s” + delete “likewise”
L.98. Delete period after “cm/s”
L.99-101: Please rewrite the sentence and place it in methodology.
L.101-102: Please improve the sentence for better clarity.
L.108: Avoid mentioning this time frame in the first line of the paragraph when the aim is to present the study area. Secondly: it was not clear to what does this time frame correspond: releases of passive larvae? collection of ovigerous female?
L.112: “artisanal fishery grounds”
L.113: How did you define the places were “crab banks”?
L.114: “were collected by” + what were the conditions of captivity? (water temperature, salinity, light)
L.1116: what was the "controlled system”?
L.117-118: After reading the manuscript, I assume this information should be moved to the section giving details on the particle tracking model. I thought you were talking about the laboratory-reared larvae.
L.118: the reference to Figure 1 should be put when you first mention the crab banks in the text. It is useless to make a descriptive sentence like this one. This technical comment is valid for other sentences in the text that state that “results appear in Table/figure X”
Figure 1. To improve the figure, I strongly advise to:
- Show a little map of Thailand in a corner of that map. This will spatially contextualise your study area.
- Indicate the CRS you are using in the caption.
- Be careful with the colour suggestion. Think about the colorblinded people looking at your article. It exists palettes of color for them.
- The seagrass areas are hardly seen if I don’t zoom in on your figure. I suggest to fill in the polygons, and to absolutely not use green for the filling.
- The size of the legend name of the crab banks is too small. See my suggestion below.
- What do station “test 4” and “test 5” correspond to?
- Map Legend Clarity: The legend in the map is challenging to interpret. You used a blue dot for crab banks in the legend, but they have diverse colors on the map. Additionally, numbering both crab banks and seagrass areas with Arabic numerals is confusing. Here are suggested improvements:
- Crab Banks:
- Retain Arabic numerals for the blue crab banks.
- On the right side of the graph, place the names of the crab banks corresponding to each number, similar to the approach used for seagrass areas. Keep them in black color
- Remove the names from the maps.
- Seagrass Areas:
- Use letters for seagrass areas on the map. Keep them in black color.
- On the right side of the graph, indicate the names of the seagrass areas for each letter.
By implementing these changes, the legend will be more intuitive and facilitate a clearer understanding of the map.
L.130: It is better to say “horizontal swimming”. Motion can refer to their advection with the currents.
L.130. A reference to the host website or a reference presenting Delft3D is required.
L.137-150: If this computation is described by Delft3d documents, it is useless to present these equations here. Keep the essential to describe how the model works. For inspiration, look at one recent publication like the one of Dr. Sato: https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.12399
L.159: Units are missing for the coefficients of diffusivity.
L.160: What does quoting the reference 20 bring to your mns? Was it them who set up the number of particles to be 10000? + Better specify that 10000 particles were released at each crab bank location.
L.161: Give reference for setting releases at spring tide and low tide? + “banks at spring tides” + “1 meter deep”
L. 164: it is confusing to read “behaviour” when you stated particles were passive. Please, clarify.
L.164: “accounting for…within our study area”. Are you referring to the monsoon? What do you mean with this part of the sentence?
L.166: “the transport duration was set to 14 days in reference to the duration of the planktonic life of the crab [REFERENCE NEEDED]” or something like this.
L.168-169. Delete this sentence and describe the Table 1 with words. You should also remind the reader why you select to carry out particle transport model in the year 2022.
L.175: Clarify this section of the sentence. What happen to the crabs between the moment they were caught to the moment they arrived at the laboratory?
L. 176: Provide information on the water temperature of the tank and the feeding of the females.
L.178: How long was the egg incubation?
L.180: “To assess the accuracy of the larval dispersal simulations”
L.181: “4 million zoea”: how did you know you had that many? When (date) were they released? + It is not named “Sukorn Station” in Figure 1 but Test 4. Please, modify.
L.182-183: Why was it representative? + “ for larval release”
L.185: what is the frame size of the plankton net? What was the velocity of the boat when sampling with the net? + “(mesh of 103 micrometers)”
L.187: the buoy release has not been mentioned. Nor the way the buoy was tracked + you should represent the trajectory of the buoy with the stations were larvae were sampled.
L.187: “all Zoea” do you mean : the plankton in general? Did you sample only the zoeal stage of the crab in your net? Or did you get other species, hence the need for microscope taxa identification?
L. 189: “and represented in the unit of individual”. I suggest deleting. It is not relevant.
L.191: “To validate the modelled settlement sites of”
L.192: “using 20 collectors… deployed in a coastal area…”
L.193-194: Are they the transport simulation you described above? I have issue to understand the timeline of the study? When was the buoy deployed and when was released the laboratory-reared larvae? When were the collectors put in water?
L.196: Why 24 hours only?
Figure 2: This is not an “illustration” but a picture. I would have liked to have an illustration of your collectors concepts and the process of trapping the larvae.
L.205 the subhead sounds very methodological. Change your subhead with a title summarising the findings you made.
L.206: Delete “this investigation examined”.
L.207: “and field observation”. this information does not fit with the subhead of the section.
L.208: “influenced by various hydrodynamic variables”: you don’t specify which ones. Please explain why do you think they influenced the dispersal.
L.213:214: Specify the range of the vertical water velocity values and identify the locations you mentioned. This result is going nowhere as it is written and is very conceptual.
L.214-216: This does not mean anything as it is written. Do you mean megalopa went towards northern and southern places from their origin? Which sources were the ones with Megalopae going to upper region or lower region. Add indications to the reader. I am lost and I don’t know where to observe these patterns in the figures.
L.216-217: See my fourth main comment.
L.217-218: Specify the majority: what percent was it? How do you consider they were dispersed “near” their source? What was the distance of dispersal for these larvae. Similarly, specify percentages for the larvae you esteemed as going offshore, and how far they went from their sources. Specify if some sources were providing more larvae going offshore. All this information is for the future readers to use it and to quote you. This information can also help for conservations. I suggest to put percentages and other information per sources in a new table.
L.219: “prediction” is a word that is used for statistical modelling. Here, and for the rest of the mns, I recommend using the word “estimations”
L.219-220: This sentence is too general. Your whole place is coastal. So where else would they settle? This information repeated with the information you said in the previous sentence.
Figure 3. To improve the figure and the clarity of your results, I strongly advise to:
1. Redefine the colour palette to accommodate colour-blinded readers.
2. Improve the context of the Figure caption.
3. Increase the visibility of the Seagrass areas.
4. Redesign the two figures to ensure they effectively convey the key point of your results described in the text. The current representation lacks clear illustrative value. Present information about larval dispersal per sources and time in a new table (% offshore, % retained). For Figure 3. a), consider presenting the spread information for relevant sources based on the results stored in the suggested new table. This figure a) is too complex for an accurate understanding of the spread, and you probably have overlapped dots that prevent to see the full scale of the larval spread. For Figure 3.b), opt for a density (i.e., heatmap) maps instead of discrete ranges. Please, maintain the consitency in the value range across all figures.
- Pay attention to the order of your elements on the maps to avoid obscuring the harbour name with the discrete points.
- Like for Figure 1, keep the names of the harbour on the side, increase the size of the source number ID for better visibility.
L.220-228: Improve this sentence and provide more details on connectivity to seagrass zones. Specify the percentage of particles reaching seagrass beds, regardless of the destination. For example, “X% of megalopa during Inter-Monsoon reached all (?or does some seabed not connect at all?) defined seagrass beds.” Then, you can go into the details you have. Clarify whether sources of larvae connected to nearby seabed.
L.233: Replace “the most” by “the highest”
L.234: Begin your sentence with “During the southwest moonsoon”.
L.238: “due to the higher”.
L.237-239: Include this statement earlier in the text, around l.228-229. Provide the context: “During the three release time, the settlement was always relatively high for the seabeds Koh Mook and Ao..” or something similar.
Table 2:
1. Modify this table in line with the suggestions made for Figure 1.
2. Rename the column “source of Crab Bank” to “Source of Crab Bank connected to Seagrass Bed”.
3. Order the IDs of the sources in ascending order. For example, in the first row, you put 1,2,3,[…] for inter-monsoon, but 6,1,2,[…] for Southwest monsoon.
L.243: “southwest monsoon wind” it will be interesting for the reader to have an idea of the Wind field for the three release events.
L.244: “within the study areas”: which areas are you talking about?
L.247: “(see Figure 4a)”. I clearly saw the presence of particles in river mouths in the Figure 3. Why was it not mentioned in the previous paragraph?
L.248: Don’t go to the next line. This paragraph aligned with the information given in the previous sentences.
L.250: This statement is out of relevance.
Figure 4: Please refer to my technical comments on Figure 3.
L.262-263: I don’t observe this statement in Figure 5. It is hard to know about what you are referring.
Figure 5: Please refer to my technical comments on Figure 3.
L.270-272: Please, refine this text. Don’t refer to a figure at the beginning of a paragraph. You should put the location of the sampled larvae on the figure.
Figure 6: Add the release locations of the laboratory larvae and virtual larvae. Respect colour-blinded people (no green and red). Replace “observation” by “buoy trajectory”.
L.282: “Fourteen days after releasing laboratory-reared larvae that had recently hatched”
L.283: Do you mean “all deployed collectors”? You should nuance your findings, because it seems that the tracked larvae went into the indented area and not over the area with collector.
Figure 7, left panel: do a density map. Indicate the location of larval release. Right panel: if the big yellow dot indicate the CBLC location, please change the format and the color of the dot. It is confusing. What does the number on dots mean? Tracked virtual larvae? It would be better, again, to do a density map.
L.292-304. I suggest rewriting this paragraph. This is highly repeated with the methodology, and hardly discussed the results. Figure should never be new and mention in Discussion. It would have been better to show it in the Methodology. If you wish to talk about the dispersal results of your study, focus on the fact your species was quite a coastal resident into your study area, and compare this results with other similar studies on crabs.
Figure 8: If you put coloured arrows to represent the velocity intensity, keep the arrows at the same size and indicate the direction of the currents. “vertically averaged current velocity” What about the inter-monsoon period?
L.3111-314: Refine the sentence. A piece of this sentence belongs to results.
L.322: “the release of crab larvae”: Which larvae? laboratory-reared? Or virtual particles? If virtual particles, I disagree with this suggestion. If laboratory-reared, clarify if a program of releasing laboratory-reared larvae is planned for the recovery of the crab population and discuss with existing program of active population restoration (I know it exists publications of active restoration of corals, for example). You can also valorise the fact that transport modelling can be a tool to select locations of larval releases that are favourable to their settlement.
L.339: Again: “releasing the crab larvae”: which ones? Virtual or Laboratory-reared?
L.352-354: this should be refined and put in Results.
L.354-356: This should be in the section about the study area in Methodology.
L.360: the cluster of crab larvae was not clear in your figures nor it was properly described in Results.
L.373: “25 millimetres” that is an information that should have been provided earlier in the mns, when you mention “young and small-sized crab”.
L.386-288: Improve the clarity of this sentence
Comments on the Quality of English LanguageI hope the journal offers English editing services to assist the authors in refining their phrasing.
Author Response
Responses to the reviewer’s comments
Water-2781630: Larval Dispersal Modelling of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) from the Crab Banks along the Coast of Trang Province, Southern Thailand
Section: Oceans and Coastal Zones
Special issue: Coastal Management and Nearshore Hydrodynamics
Authors: Nikom Onsri, Itchika Sivaipram, Phurich Boonsanit, Kattinat Sagulsawasdipan, Suriyan Saramul*
******************************************************************************
We would like to thank two anonymous reviewers for their valuable comments and suggestions. The authors agree with all suggestion and comments provided by the reviewers, and we believe that those suggestions could strengthen and improve our manuscript prior to publication. Therefore, we have corrected and added more details regarding the comments and suggestions assigned by the reviewers. In our revised version, all corrections and modifications are highlighted with yellow colour with the comments.
Reviewer II
Main Comments:
- The vocabulary should be accurate every time there is a risk of confusion. It was challenging to understand which transported objects were referred too (e.g., buoys, laboratory-reared larvae and virtual larvae).
Answer: Thank you so much for this comment, we apologised for some points that we made confusion in the results and discussion section. Therefore, we have already corrected to specify the vocabulary for a better understanding and accuracy, as suggested by the reviewer II. We used “virtual larvae” to refer to the results of larvae based on our modelled simulations, while “laboratory-reared larvae” mean the larvae that were hatched and reared in our laboratory.
- Your introduction should be reordered and modified. It is hard to follow the narrative line. a) Don’t blend fisheries and biology as you did in the initial paragraphs of your manuscript. This was my understanding of the current state of the introduction: L.28-31: General Biology, L.31-33: Economic activity. L.33-42: Reproductive ecology. L.42-50: Economic activity again. L.50-56: Conservation. L.56-59/60: Methodology (It should be removed from the introduction). L.60-65: Knowledge gap. L.66-87: Benefit of modelling. L.97-101: a melting pot of various information. L.101-105: Benefits of the study. b) I think you need to enhance the importance of the monsoon in the introduction. I am not familiar with this event and I don’t know if it is common to study its impact on dispersal studies like yours. d) State more specific objectives. Understanding the dispersal of a species is one thing you did, but in the results, there was a clear interest in the larval arrival over seagrass bed and on the monsoon event. You should articulate your objectives for this.
Answer: We have already modified our introduction a bit regrading the comments and suggestions of the reviewer II. We reordered some paragraphs in the introduction section. We started the first paragraph with the biology and ecology of the blue swimming crab Portunus pelagicus, followed by economic activities of P. pelagicus in Thailand and neighbouring countries, decreased populations of P. pelagicus caused by overfishing and overexploitation, the Crab Bank project and its activities in relevant to the conservation and fishery management of P. pelagicus in Thailand (please see our revised version; 1st-3rd paragraph in the introduction section).
In the third paragraph mentioned about the Crab Banks, we also defined the knowledge gaps about this conservation strategy, which shed the light to our research introduction and rationale.
For the 4th paragraph, we highlighted the importance of determining larval dispersal and settlement patterns that these studies are very crucial for understanding population ecology and recruitments of marine animals having their larvae as meroplankton.
For the 5th paragraph, we introduced the use of numerical models, such as a particle tracking model to assess dispersal patterns and transport of marine larvae.
For the 6th paragraph, we described ecological information about seagrass meadows in our study site (Trang coastline, southern Thailand) following the suggestion of the reviewer II.
- Although I feel a scientific protocol in your methodology has been respected, you don’t provide enough details for the methodology to be trusted. a) Restructure the Methodology. The Paragraph 2.1. included laboratory details that should be provided in another section. More exactly, in the Paragraph 2.1., I would expect information on the hydrodynamics, monsoon and wind (maps and references included) on the study area. Paragraph 2.2 is messy. Improve clarity and clearly divide the text between: field/observation works and modelling. To sum up, structure your methodology in: study area, particle tracking modelling experience (hydrodynamic model description, particle transport model description and its set up, description of outputs analysis), laboratory/field experiments (collection of crabs, water tank conditions, larval release and sampling description, larval analysis), validation of models with buoy release (buoy type, release and tracking description) and larval sampling (description of analysis). b) Is the hydrodynamic model validated? Has the model been used in other studies? c) Clarify the timeframes of your study. When were female collected? When were laboratory-reared larvae released? When was the buoy released?
Answer: We have revised the materials and methods in our revised manuscript. We have added significant information in the section of materials and methods and also reordered the subheadings following your suggestions (please see our revised version).
In the section of the study area, we provided additional information about hydrodynamics, monsoon and wind patterns which occur in the study site. We made a new figure demonstrating the wind direction and speeds in each monsoon period (please see the figure 2). Necessary details about seagrass meadows along the Trang coastline, including the status, seagrass coverages, the numbers of seagrass species and the dominant seagrass species, have been added into the study area section regarding your suggestions.
In the subheading of particle tracking modelling experience , we have described the calibration of our hydrodynamic models, ensuring that our hydrodynamic models are valid prior to simulating the particle transport model.
For the laboratory experiments, we have revised this section a bit following your comments and suggestions. We explained more about the collection and source of the berried crabs, water tank conditions, and the egg incubation time and protocols.
In the section of validation of models with buoy release, we described more details about the setup and timeframe of a particle tracking model, buoy’s release, buoy’s monitoring after the release, and the larval release (a release location and release time). For the larval release and sampling, we have added more necessary information about the diameter of plankton nets, a mesh size of plankton nets, and the boat’s velocity during sampling the zoeae using zooplankton nets (please see our revised version).
B: Is the hydrodynamic model validated?
We have already calibrated the hydrodynamic model prior to applying the model to the particle tracking model. Our hydrodynamic model simulated by Delft3D-FLOW was calibrated with the water levels and currents obtained from our field investigation at Sukorn Island (for the water level calibration), the Rajamangala CBLC station (for the water level calibration), and Koh Njai (for water current calibration). Following the calibration, we ensure that our hydrodynamic model is valid and has high accuracy, as evidenced by the coefficient of determination (r2), mean absolute error (MAE), and root mean square error (RMSE) as shown in the table and figure below.
A table demonstrates information of calibrated stations, locations, and statistical results based on the calibration between our hydrodynamic model and data obtained from field investigation.
|
station |
location |
r2 |
MAE |
RMSE |
|
Sukorn Island |
533580.54 m.E and 786492 m. N |
0.97 |
0.10 |
0.13 |
|
the Rajamangala CBLC station |
564425.79 m. E and 832707.05 m. N |
0.99 |
0.07 |
0.09 |
|
Koh Njai |
524917 m. E and 818533 m N |
0.98 |
0.08 |
0.10 |
A figure demonstrates the calibration of water levels over time (each hour) between our hydrodynamic model and data obtain from field observation at Sukorn Island in April 2022. The statistical values, including r2 , MAE and RMSE, and amplitudes and phases of water levels are shown in the figure.
A figure demonstrates the calibration of water levels over time (each hour) between our hydrodynamic model and data obtain from field observation at the Rajamangala CBLC station in April 2022. The statistical values, including r2 , MAE and RMSE, and amplitudes and phases of water levels are shown in the figure.
A figure shows the calibration of current speeds and directions between our hydrodynamic model and data obtain from field observation at Koh Njai in April 2022.
- Results should be reordered. a) First, talk about the general results on connectivity and dispersal around Table 2. b) Then, talk about the variability of larval spread with monsoon period through Figures 3,4,5. c) You should focus the description of your outputs on releavant seabed and/or sources. For example, at l.216-217, you stated that the larval transport was distinct accordingly to its source location but it was hardly supported with values. To illustrate your results for specific locations, I suggest to focus on a few relevant sources, either noticed from the results in Table 2, sources you mention in the Discussion because of their proximity to estuary, or because the dispersal patterns from these sources were interesting (see next sentence). I suggest to make a new table where the dispersal information is clearly visible for each sources (I provided more information in the technical comments).
Answer: Thank you for your suggestions, we have already reordered our results. Firstly, we described an overview of larval dispersal patterns simulated by our particle tracking model coupled with hydrodynamic variables. For the second paragraph, we mentioned about the larval dispersal patterns, relying on the effects of monsoon wind patterns. In our revised version, we counted and calculated the numbers of virtual crab larvae which were transported into offshore areas (water depth > 20 m), inshore areas (water depth < 20 m), and estuarine areas (river mouths and tributaries), following your suggestion. This additional analysis could make the results of larval dispersal clearer, having the significance and implications for the crab larval releasing activities by the Crab Banks in the future. As the larvae dispersal patterns likely depended on released stations, we also divided the dispersal patterns into three main regions, including Region a, b and c. Overall, the most virtual larvae released from each region were still retained within inshore areas near their released stations (please see in Figure 4-6).
- L.269: The whole section is challenging to understand. You mixed in so many information that I had trouble to associate the methodology with the results. I suggest to create two subsections to distinguish results from the pelagic sampling and megalopa collection experience
Answer: We have already revised the result version (please see our revised version).
- a) Rewrite discussion for better comparison with published papers and cleared organisation of ideas per paragraph. Valorise your results and compare them to other studies, particularly emphasising the significance of monsoon influence. From what I read, I understood that: * First paragraph is about Coastal retention while passive. Discuss the importance of having the tides and a short pelagic life. * Second paragraph is about the importance of being transported to estuary. The idea is good but the text should be refined. * Third paragraph is on the importance of the monsoon schedule in the larval transport. I think you had already good material in the current discussion, but it should be more valorised (is it one of the first studies with monsoon influence?) and compared to other studies. * Fourth paragraph is on the use of the discovery of crab connectivity to seagrass for conservation. * Fifth paragraph is to remind the model estimation aligned with real data. It needs a bit of improvement for clarity, but it was interesting. b) The discussion mention a new conservation action (releasing laboratory-reared larvae to key location that are favourable for connectivity) without defining and developing the idea properly. Develop and define this idea, addressing potential risks associated with this "seeding" method.
Answer: The authors are in agreement with your suggestions, and we have already refined the discussion part following your comments (please see our revised version). Firstly, we discussed the coastal retention of virtual larvae after the release from the Crab Banks, such as possible factors regulating the coastal retention of virtual larvae. We also highlighted the importance of a short-pelagic duration of P. pelagicus larvae and their coastal retention regulated by tidal-driven currents. For the second paragraph, we discuss the effects of monsoon periods on the larval dispersal patterns, followed by the third paragraph that explained about the influences of the southwest monsoon on being transport of virtual larvae into estuaries (river mouths and estuarine tributaries). We also suggested some strategies in larval releasing activities during the southwest monsoon, avoiding being transported into estuaries (please see our revised version).
Technical comments suggested by the reviewer II
L.10: Clarify the scope of “well-known”. Is it specific to Thailand only? or widely studied worldwide? In Asian countries?
Answer: We have clarified this sentence in the abstract (please see our revised version).
L.11-12: “while studies…not well-understood”. Make a transition from fisheries to the knowledge gap more explicitly. You shall make a statement about the general ecological knowledge of the crab, eventually emphisizing its importance for the fisheries.
Answer: We have already refined this sentence (please see our revised version).
L.12: Delete “here”.
Answer: We have corrected this point following your comment.
L.14-15: For Delft3D-PART and afterwards, clearly stat that Delft3d-PART is the Lagrangian module of Delft3d, not the hydrodynamic model. Keep the name of that module for the main manuscript not the abstract. In the abstract, just state that you used a Particle transport model to simulate the larval dispersal. Also, explain briefly why you were interested in the monsoon event? It is needed to justify your interest for this.
Answer: We have corrected this point, and we replaced the Lagrangian particle tracking with the hydrodynamic model to specific a type of our models.
L.17: “that the crab larvae significantly arrived along both…”
Answer: We have corrected this point following your comment.
L.17: What do you mean by “upper and lower”?
Answer: We have revised this sentence to make it clearer (Please see our revised version).
L.18: You mention hydrodynamic factors, but in your manuscript and in your abstract, I did not know which one you are talking about. Be more specific.
Answer: We have specified hydrodynamic factors influencing the larval dispersal and settlements of virtual larvae P. pelagicus. The primary hydrodynamic variables are tidal-driven currents and monsoonal wind induced currents (Please see our revised version).
- 19: Tie “seasonality” to the "monsoon" feature. It is the backbone of your analysis, after all.
Answer: We have refined our abstract following your comments (please see our revised version).
L.34-35: “are dominantly missing”
Answer: We have corrected this point following your comment.
L.36: “ovigerous females release their carrying eggs” is confusing. Did you mean “The berried females releases their eggs”? Specify wether eggs hatched immediately or within a short time frame after their release. It is important information that should appear in the main text of the manuscript.
Answer: We have refined this section. We mean “The berried females release their eggs”, and we have specified that the eggs hatch into the 1st zoeal stage immediately.
L.37: “eggs hatch and larvae moult through four zoeal stages until metamorphosing in one megalopa…” or something like this.
Answer: We have refined this section following your suggestion.
L.38: Provide information about the size of young crab.
Answer: We have added the size of young crabs (please see our revised version).
L.44: “ Thailand contributes the fishery…” Please rewrite for clarity.
Answer: We have modified this sentence to make it clearer.
L.46: Provide the timeframe for the observed decrease in crab population
Answer: We have revised and added this information (Line:47-50).
L.47-48: “which it probably has a significant threat” Do you mean “which probably causes a significant threat…”?
Answer: Yes, we mean as your understanding, we have revised this sentence.
L.48: Delete “likewise”
Answer: We have removed it.
L.49: what do you mean by “harvesting”? Harvesting is related to crop fields and not a suitable term.
Answer: We have changed the word to make it more suitable for crab fisheries (please see our revised version).
- 50: delete “key”
Answer: We have removed it.
L.54: Provide the ID number and the hosting institution for the “crab Bank project”
Answer: We have added information about the hosting institution for the “crab Bank project” in the introduction section (Line: 54-57).
L.55: “on a mission to protect and recover P. pelagicus populations/stocks to reach its sustainable exploitation and fishery management.”
Answer: We have already corrected this point following your suggestion.
L.56-59: This sounds like Methodology and it was a confusing text. About “carrying eggs”: see earlier technical comment. “after hatching for a day”, do you mean the incubation time was one day? Or did you wait one day before collecting larvae? I think these two sentences should be replace by specific concepts. In the next sentence, you refer to “enhancing restoration”. So, talk about active restorations facts which seed individuals (it is done with corals, for example).
Answer: We have revised this section (see Line 57-59).
L.63-65: Avoid the repeatiton from L.41-42.
Answer: We have already corrected this point.
L.66: Delete “In the present day”.
Answer: We have deleted that phase.
L.66-67: Please rewrite “a numerical model …hydrodynamic model” for clarity
Answer: We have revised this section (Please see the introduction section in our revised version).
L.68: “This result based on the model…” It is confusing and I don’t think it fits here.
Answer: We have corrected this point following your suggestion.
L.72-74: Why these species? Why these studies? Nowadays, many studies exist on the larval transport. It is better to refer to general articles talking about larval transport concepts than giving examples that are not related to your study. It could have been interesting to mention studies of dispersal for P. pelagicus, for examples, or other species near your study area.
Answer: We have refined a structure of storytelling of this section (see line 67-83).
L.76: Instead of assuming no swimming activity for larvae, which is very unlikely, state that the passive larval transport relies solely on oceanography. It is quite acceptable to simulate passive particles if nothing is known on the larvae
Answer: We would like to convince readers that passive models are still useful and effective tools for assessing larval dispersal patterns of marine animals, despite having active models in the present day. Moreover, our animal model (P. pelagicus larvae) also lacks the ability to swim against horizontal currents, indicating that passive models can be employed in our study.
L.78-79: Provide more relevant and specific information about larval traits, which should, somehow, be related to your text written below.
Answer: We have revised this paragraph (please see the introduction section in our revised version).
L.80: Delete: “As mentioned in a previous study”.
Answer: We have removed that phase.
L.81: “based on laboratory and field observations”.
Answer: We have corrected it following your suggestion.
l.82: Where does 56% come from? Reference [16]? In that case, put the reference next to the number.
Answer: we have added the reference for this fact (line 93).
l.83: “over their development”
Answer: We have corrected it following your suggestion.
L.87: Delete “likely” + modify the sentence to “to set up biophysical models”
Answer: We have corrected it following your suggestion.
L.89: How many is in “there are many”? Can you provide an idea of the meadow coverage in your study area?
Answer: We have already added more information (see line 100-116).
L.90: Specify the size for “*Large* seagrass meadows” and discuss their protection status, seagrass species compositions, and potential ecosystem services in a few words. More details can supplied in the section 2.1.
Answer: We have already added more information (see line 100-116).
L.91-92: This is repetitive with previous texts.
Answer: We have corrected it following your suggestion.
L.93: Delete Here.
Answer: We have removed it.
L.94: “approach with the Delft3D-Part model”
Answer: We have corrected it following your suggestion.
L.94-96: this should be move to methodology.
Answer: We have removed these sentences to the materials and methods.
L.97: Delete period after “cm/s” + delete “likewise”
Answer: We have corrected it following your suggestion.
L.98. Delete period after “cm/s”
Answer: We have corrected it following your suggestion.
L.99-101: Please rewrite the sentence and place it in methodology.
Answer: We have removed these sentences to the materials and methods.
L.101-102: Please improve the sentence for better clarity.
Answer: We have refined this sentence (Please see our revised version).
L.108: Avoid mentioning this time frame in the first line of the paragraph when the aim is to present the study area. Secondly: it was not clear to what does this time frame correspond: releases of passive larvae? collection of ovigerous female?
Answer: We have revised this section (Please see the materials and methods in our revised version).
L.112: “artisanal fishery grounds”
Answer: We have revised this section (Please see the materials and methods in our revised version).
L.113: How did you define the places were “crab banks”?
Answer: We adopted the exact locations (latitude and longitude) of the Crab Banks along the Trang coastline and plotted them in a map.
L.114: “were collected by” + what were the conditions of captivity? (water temperature, salinity, light)
Answer: We have refined this section and added more details about the conditions of captivity in the Crab Banks (line 165-176).
L.1116: what was the "controlled system”?
Answer: We have refined this section and added more details about the conditions of captivity in the Crab Banks (line 165-176).
L.117-118: After reading the manuscript, I assume this information should be moved to the section giving details on the particle tracking model. I thought you were talking about the laboratory-reared larvae.
Answer: We have removed this information to the section of a particle tracking model.
L.118: the reference to Figure 1 should be put when you first mention the crab banks in the text. It is useless to make a descriptive sentence like this one. This technical comment is valid for other sentences in the text that state that “results appear in Table/figure X”
Answer: We have already removed that sentence.
Figure 1. To improve the figure, I strongly advise to:
- Show a little map of Thailand in a corner of that map. This will spatially contextualise your study area.
- Indicate the CRS you are using in the caption.
- Be careful with the colour suggestion. Think about the colorblinded people looking at your article. It exists palettes of color for them.
- The seagrass areas are hardly seen if I don’t zoom in on your figure. I suggest to fill in the polygons, and to absolutely not use green for the filling.
- The size of the legend name of the crab banks is too small. See my suggestion below.
- What do station “test 4” and “test 5” correspond to?
Answer: We have corrected the figure 1 following your suggestion (please see our revised version). For stations named test1-6, these stations refer to additional stations that have been planning to establish in near-future. Hence, we also added the locations of those stations in our study.
- Map Legend Clarity: The legend in the map is challenging to interpret. You used a blue dot for crab banks in the legend, but they have diverse colors on the map. Additionally, numbering both crab banks and seagrass areas with Arabic numerals is confusing. Here are suggested improvements:
- Crab Banks:
- Retain Arabic numerals for the blue crab banks.
- On the right side of the graph, place the names of the crab banks corresponding to each number, similar to the approach used for seagrass areas. Keep them in black color
- Remove the names from the maps.
- Seagrass Areas:
- Use letters for seagrass areas on the map. Keep them in black color.
- On the right side of the graph, indicate the names of the seagrass areas for each letter.
By implementing these changes, the legend will be more intuitive and facilitate a clearer understanding of the map.
Answer: We have corrected a map following your suggestion (please see our revised version).
L.130: It is better to say “horizontal swimming”. Motion can refer to their advection with the currents.
Answer: We have corrected this word.
L.130. A reference to the host website or a reference presenting Delft3D is required.
Answer: We have already added the reference for Delft3D.
L.137-150: If this computation is described by Delft3d documents, it is useless to present these equations here. Keep the essential to describe how the model works. For inspiration, look at one recent publication like the one of Dr. Sato: https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.12399
L.159: Units are missing for the coefficients of diffusivity.
Answer: The coefficients of diffusivity does not have a unit.
L.160: What does quoting the reference 20 bring to your mns? Was it them who set up the number of particles to be 10000? + Better specify that 10000 particles were released at each crab bank location.
Answer: The numbers of released particles can be varied from 100-10, 000 particles. An increase in released particles could increase the accuracy and help us to observe dispersal patterns clearer. Hence, in our study, we designed to use 10,000 released particles to assess the larval dispersal pattern.
L.161: Give reference for setting releases at spring tide and low tide? + “banks at spring tides” + “1 meter deep”
Answer: For this protocol, we follow the protocol of Crab Bank’s activities along the Trang province. Zoeae are generally released by the Crab Bank’s staffs during the spring tide and the low tide period to increase the dispersal of larvae after release. This is a reason why we set the water depth during releasing the larvae at 1 m to mimic larval releasing activities of Crab banks in daily life.
- 164: it is confusing to read “behaviour” when you stated particles were passive. Please, clarify.
Answer: We have corrected this word.
L.164: “accounting for…within our study area”. Are you referring to the monsoon? What do you mean with this part of the sentence?
Answer: We have revised this section (Please see the materials and methods in our revised version).
L.166: “the transport duration was set to 14 days in reference to the duration of the planktonic life of the crab [REFERENCE NEEDED]” or something like this.
Answer: We have already added the reference (line 232).
L.168-169. Delete this sentence and describe the Table 1 with words. You should also remind the reader why you select to carry out particle transport model in the year 2022.
Answer: We have revised this section (Please see the materials and methods in our revised version).
L.175: Clarify this section of the sentence. What happen to the crabs between the moment they were caught to the moment they arrived at the laboratory?
Answer: We have revised this section and added more information about collecting the berried crabs (line 243-259).
- 176: Provide information on the water temperature of the tank and the feeding of the females.
Answer: We have revised this section and added more information about collecting the berried crabs (line 243-259).
L.178: How long was the egg incubation?
Answer: We have added this information (line 255).
L.180: “To assess the accuracy of the larval dispersal simulations”
Answer: We have corrected this point.
L.181: “4 million zoea”: how did you know you had that many? When (date) were they released? + It is not named “Sukorn Station” in Figure 1 but Test 4. Please, modify.
Answer: Prior to the larval release at Sukorn Station, we sampled our laboratory-reared zoeae to count and calculate the density of them briefly. We have added the date of larval release (line 261-262). We have also mentioned in a paragraph that Sukorn Island station is named as Test 4 in the figure 1.
L.182-183: Why was it representative? + “ for larval release”
Answer: We chose Sukorn Island station as a representative site for larval release because there is one of the Crab Banks learning centre, which has routine activities of crab larval release. Moreover, this location is suitable for our larval release-experiment, enhancing the dispersal of crab larvae after release.
L.185: what is the frame size of the plankton net? What was the velocity of the boat when sampling with the net? + “(mesh of 103 micrometers)”
Answer: We have provided additional information (see line 271-280).
L.187: the buoy release has not been mentioned. Nor the way the buoy was tracked + you should represent the trajectory of the buoy with the stations were larvae were sampled.
Answer: We have revised and added more information about the buoy release and tracking (see line 261-280).
L.187: “all Zoea” do you mean : the plankton in general? Did you sample only the zoeal stage of the crab in your net? Or did you get other species, hence the need for microscope taxa identification?
Answer: Actually, when we sampled zoeae using zooplankton nets, we got many species of crab zoeae, not only P. pelagicus. Hence, we have to preserve the sample and identify under a light-compound microscope to count only zoeae of P. pelagicus.
- 189: “and represented in the unit of individual”. I suggest deleting. It is not relevant.
Answer: We have revised this one (please see our revised version).
L.191: “To validate the modelled settlement sites of”
Answer: We have corrected this one.
L.192: “using 20 collectors… deployed in a coastal area…”
Answer: We have corrected this one.
L.193-194: Are they the transport simulation you described above? I have issue to understand the timeline of the study? When was the buoy deployed and when was released the laboratory-reared larvae? When were the collectors put in water?
Answer: We have corrected these sections (see line 260-300).
L.196: Why 24 hours only?
Answer: Due to semi-diurnal tides in the study area, the settlement behaviour of megalopa P. pelagicus might rely on light (at daytime and at night). Therefore, we designed to place the megalopa collectors for 24 h to cover daytime and night-time, ensuring that the time period may be enough for the megalopa’s settlements in the sampling areas.
Figure 2: This is not an “illustration” but a picture. I would have liked to have an illustration of your collectors concepts and the process of trapping the larvae.
Answer: We have revised this illustration (see more details; Figure 3 with a figure caption).
L.205 the subhead sounds very methodological. Change your subhead with a title summarising the findings you made.
Answer: We have revised this point following your suggestion.
L.206: Delete “this investigation examined”.
Answer: We have deleted it from our manuscript.
L.207: “and field observation”. this information does not fit with the subhead of the section.
Answer: We have revised this section (please see the result section).
L.208: “influenced by various hydrodynamic variables”: you don’t specify which ones. Please explain why do you think they influenced the dispersal.
L.213:214: Specify the range of the vertical water velocity values and identify the locations you mentioned. This result is going nowhere as it is written and is very conceptual.
L.214-216: This does not mean anything as it is written. Do you mean megalopa went towards northern and southern places from their origin? Which sources were the ones with Megalopae going to upper region or lower region. Add indications to the reader. I am lost and I don’t know where to observe these patterns in the figures.
L.216-217: See my fourth main comment.
L.217-218: Specify the majority: what percent was it? How do you consider they were dispersed “near” their source? What was the distance of dispersal for these larvae. Similarly, specify percentages for the larvae you esteemed as going offshore, and how far they went from their sources. Specify if some sources were providing more larvae going offshore. All this information is for the future readers to use it and to quote you. This information can also help for conservations. I suggest to put percentages and other information per sources in a new table.
L.219: “prediction” is a word that is used for statistical modelling. Here, and for the rest of the mns, I recommend using the word “estimations”
L.219-220: This sentence is too general. Your whole place is coastal. So where else would they settle? This information repeated with the information you said in the previous sentence.
Answer: Regarding the queries above, we have revised many points following your suggestion (please see our revised version in the result section).
Figure 3. To improve the figure and the clarity of your results, I strongly advise to:
- Redefine the colour palette to accommodate colour-blinded readers.
- Improve the context of the Figure caption.
- Increase the visibility of the Seagrass areas.
- Redesign the two figures to ensure they effectively convey the key point of your results described in the text. The current representation lacks clear illustrative value. Present information about larval dispersal per sources and time in a new table (% offshore, % retained). For Figure 3. a), consider presenting the spread information for relevant sources based on the results stored in the suggested new table. This figure a) is too complex for an accurate understanding of the spread, and you probably have overlapped dots that prevent to see the full scale of the larval spread. For Figure 3.b), opt for a density (i.e., heatmap) maps instead of discrete ranges. Please, maintain the consitency in the value range across all figures.
- Pay attention to the order of your elements on the maps to avoid obscuring the harbour name with the discrete points.
- Like for Figure 1, keep the names of the harbour on the side, increase the size of the source number ID for better visibility.
Answer; we have already refined the figure following your suggestion (please see our revised version).
L.220-228: Improve this sentence and provide more details on connectivity to seagrass zones. Specify the percentage of particles reaching seagrass beds, regardless of the destination. For example, “X% of megalopa during Inter-Monsoon reached all (?or does some seabed not connect at all?) defined seagrass beds.” Then, you can go into the details you have. Clarify whether sources of larvae connected to nearby seabed.
Answer: We have revised many points following your suggestion (please see our revised version in the result section).
L.233: Replace “the most” by “the highest”
Answer: We have corrected this point.
L.234: Begin your sentence with “During the southwest moonsoon”.
Answer: We have corrected this point.
L.238: “due to the higher”.
Answer: We have corrected this point.
L.237-239: Include this statement earlier in the text, around l.228-229. Provide the context: “During the three release time, the settlement was always relatively high for the seabeds Koh Mook and Ao..” or something similar.
Answer: We have revised many points following your suggestion (please see our revised version in the result section).
Table 2:
- Modify this table in line with the suggestions made for Figure 1.
- Rename the column “source of Crab Bank” to “Source of Crab Bank connected to Seagrass Bed”.
- Order the IDs of the sources in ascending order. For example, in the first row, you put 1,2,3,[…] for inter-monsoon, but 6,1,2,[…] for Southwest monsoon.
Answer: We have modified this table and added more information relevant to the current status and coverage of seagrass meadows (table 3 in our revised version).
L.243: “southwest monsoon wind” it will be interesting for the reader to have an idea of the Wind field for the three release events.
Answer: We have added a figure demonstrating wind speeds and directions across three monsoon periods (figure 2 in our revised version).
L.244: “within the study areas”: which areas are you talking about?
Answer: We have corrected this point.
L.247: “(see Figure 4a)”. I clearly saw the presence of particles in river mouths in the Figure 3. Why was it not mentioned in the previous paragraph?
Answer: We have revised this point.
L.248: Don’t go to the next line. This paragraph aligned with the information given in the previous sentences.
Answer: We have corrected this point.
L.250: This statement is out of relevance.
Answer: We have corrected this point.
Figure 4: Please refer to my technical comments on Figure 3.
Answer: We have corrected this figure following your suggestion.
L.262-263: I don’t observe this statement in Figure 5. It is hard to know about what you are referring.
Answer: We have revised this point.
Figure 5: Please refer to my technical comments on Figure 3.
Answer: We have corrected this figure following your suggestion.
L.270-272: Please, refine this text. Don’t refer to a figure at the beginning of a paragraph. You should put the location of the sampled larvae on the figure.
Answer: We have corrected this point.
Figure 6: Add the release locations of the laboratory larvae and virtual larvae. Respect colour-blinded people (no green and red). Replace “observation” by “buoy trajectory”.
Answer: We have corrected this figure following your suggestion.
L.282: “Fourteen days after releasing laboratory-reared larvae that had recently hatched”
Answer: We have corrected this point following your suggestion.
L.283: Do you mean “all deployed collectors”? You should nuance your findings, because it seems that the tracked larvae went into the indented area and not over the area with collector.
Answer: We have revised and explained more about the results (please see our revised version).
Figure 7, left panel: do a density map. Indicate the location of larval release. Right panel: if the big yellow dot indicate the CBLC location, please change the format and the color of the dot. It is confusing. What does the number on dots mean? Tracked virtual larvae? It would be better, again, to do a density map.
Answer: We have revised the figure and explained more details in the figure caption.
L.292-304. I suggest rewriting this paragraph. This is highly repeated with the methodology, and hardly discussed the results. Figure should never be new and mention in Discussion. It would have been better to show it in the Methodology. If you wish to talk about the dispersal results of your study, focus on the fact your species was quite a coastal resident into your study area, and compare this results with other similar studies on crabs.
Answer: We have revised the whole section in our discussion (please see our revised version).
Figure 8: If you put coloured arrows to represent the velocity intensity, keep the arrows at the same size and indicate the direction of the currents. “vertically averaged current velocity” What about the inter-monsoon period?
Answer: We have made a new figure demonstrating the current speeds and directions (see figure 10 in our revised version).
L.3111-314: Refine the sentence. A piece of this sentence belongs to results.
L.322: “the release of crab larvae”: Which larvae? laboratory-reared? Or virtual particles? If virtual particles, I disagree with this suggestion. If laboratory-reared, clarify if a program of releasing laboratory-reared larvae is planned for the recovery of the crab population and discuss with existing program of active population restoration (I know it exists publications of active restoration of corals, for example). You can also valorise the fact that transport modelling can be a tool to select locations of larval releases that are favourable to their settlement.
Answer: We have revised the whole section in our discussion (please see our revised version).
L.339: Again: “releasing the crab larvae”: which ones? Virtual or Laboratory-reared?
Answer: We have revised the whole section in our discussion (please see our revised version).
L.352-354: this should be refined and put in Results.
Answer: We have revised the whole section in our discussion (please see our revised version).
L.354-356: This should be in the section about the study area in Methodology.
Answer: We have revised the whole section in our discussion (please see our revised version).
L.360: the cluster of crab larvae was not clear in your figures nor it was properly described in Results.
Answer: We have revised the whole section in our discussion (please see our revised version).
L.373: “25 millimetres” that is an information that should have been provided earlier in the mns, when you mention “young and small-sized crab”.
Answer: We have already mentioned the size of young crabs in the introduction section (please see our revised version).
L.386-288: Improve the clarity of this sentence
Answer: We have revised the whole section in our discussion (please see our revised version).
Author Response File: Author Response.pdf
