Using Drone Footage to Analyze the Effect of Diver Presence on Juvenile Manta Ray Behavior

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents an interesting topic, but it needs improvement in the references, clarity of methodology, figure presentation, and depth of discussion. Careful revision will increase both readability and scientific impact.

• Some key statements are presented without sufficient citation (e.g., Line 55–60).
• Suggestion: Add references to recent studies (last 5 years) to strengthen the research gap and context.
• Suggestion: Improve the logical flow by clearly linking background studies to the objectives.
• The gap is mentioned but not clearly distinguished from previous works.
• Suggestion: Explicitly highlight how your study is different and why it is necessary.
• The description of methodology is brief and lacks detail in sampling and experimental design.
• Suggestion: Provide clearer step-by-step descriptions, including parameters, instruments, and data processing techniques, to allow reproducibility.
• Suggestion: Include justification for chosen methods (why these were selected over others).
• Mistake: While results are presented, some figures and tables are not fully explained in the text (e.g., Table 2 at Line 230).
• Suggestion: Ensure that every figure and table is clearly described and interpreted within the results section.
• Figures & Tables (Throughout, esp. Lines 220–240, 260–280)
• Some figures lack sufficient resolution and clarity, and table captions are not always self-explanatory.
• Suggestion: Improve the formatting and ensure all figures are high quality with clear legends.
• The discussion overlaps with results; some sentences repeat findings without deeper analysis.
• Suggestion: Focus more on interpretation, comparison with existing literature, and implications of findings.
• Mistake: Several references are outdated and formatting is inconsistent (missing page numbers, incomplete journal names).
• Suggestion: Update with recent studies, check all formatting according to journal guidelines, and ensure every in-text citation appears in the reference list.
• Some sentences are too long and difficult to follow (e.g., Line 65–70, Line 145–150).

Comments on the Quality of English Language

The English language is generally understandable, but the quality is average and requires improvement.

• 1. Long and complex sentences reduce clarity (e.g., Lines 65–70, 145–150).

  2. Grammatical errors and awkward phrasing appear in several places (e.g., misuse of verb tenses and prepositions).

  3. Inconsistent use of technical terms—some terms are repeated in slightly different forms, which may confuse readers.

  4. Transition between paragraphs is sometimes weak, affecting the flow of ideas.

  5. Minor punctuation and formatting issues (missing commas, inconsistent use of capital letters).

Author Response

Please see attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors collected drone imagery before and after a diver entered the water and used the imagery to estimate the impact of the diver on the manta behavior. There is a good background in the introduction, but the paper is very long and should be condensed. The methods section also needs a better explanation, specifically why the Marvok models were chosen and the steps for video annotation. The figures can be repetitive, and I would encourage the authors to move some of them to the supplementary section. Overall, the study is an interesting pilot study that others can build on.  

• The introduction is very long and should be condensed. It is also missing how your methods compare to traditional methods. How do researchers collect these data without the drone? Why is the drone better? What are the limitations of using the drone for this research? 
• There is no mention of what a Markov Model is in the introduction. It should be included, as well as past applications and relevance to the study. It is not introduced until the methods, and its value is not clear. If it is not that important, it should be removed from the title. 
• Line 142 - 10 meters is a relatively low flight altitude. What evidence do you have to suggest the drone itself is not affecting manta ray behavior? There are a few studies that have explored the minimum flight altitude for cetaceans and elasmobranchs; they should be cited here. 
• Line 147 - this is a major design flaw, or at least something that needs to be addressed. Your study is not looking at the impact of divers, it is looking at the impact of boat activity and divers. Did you have a minimum distance that the boat had to maintain? How much distance did the diver maintain? Did the diver actively chase the manta to collect the image? This will have a large impact on your results and needs to be clarified. 
• The video analysis section is missing some important information, such as the software used to annotate the video. Did you annotate it? What were your quality assurance and quality control procedures? Did only one author annotate? Line 233 suggests multiple observers. I am not sure what that means, but I am assuming it is related to this comment. 
• Table 1 is missing a caption.
• A figure of a manta displaying the different behaviors would be extremely helpful. This could be a diagram or just drone image examples of the different behaviors. 
• I am not sure if the videos are long enough to properly determine the impact of divers on the manta behaviors. Did you collect any videos long enough to see how long it took the mantas to return to "no diver" behavior after the diver left? 
• Table 2 - remove the significance column and replace it with asterisks that demonstrate significance. This table needs to be formatted better so the text does not spill over. There appears to be a row of data missing for the "no diver" row for Lobes (excluding feeding). Format the wingbeat line in the same way as the rows before, only mention once.
• The figures are low quality; make sure to provide the full resolution version for the final MS.
• Fix spelling mistake in the first caption in the supplementary section.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript titled "Using drone footage and Markov models to analyze the effect of diver presence on juvenile manta ray behavior" presents interesting information on the behavior of juvenile rays. The study presents innovative research methodologies, as well as thorough data collection and analysis. The authors provide an assessment of the potential use of tourism activities in the area. Although the manuscript has certain details that need to be corrected, I believe it can be accepted after these corrections are made.

Introduction

Line 53: “Some species of dolphins (Tursiops spp.)” probably is more adequate.

Lines 103-106: It should be moved to the beginning of the introduction. Authors repeated the concept.

Lines 106-120: I think authors should consider eliminating this paragraph. The introduction is too long, and I think this paragraph doesn’t add any important information. Maybe is more interesting if you use this paragraph in the discussion.

Line 124: reference in italics

Methods

Line 138: Present the characteristics of both drones (weight, size, sound, etc.)

Please add information about how the actors identified the juvenile stage.

Line 143: double spaced.

Line 189: double enter.

Line 218: ANOVA? (acronym?)

Results

Line 227: The beginning of this paragraph looks strange, it is hard to understand, please simplify. I think is better if you simplify this paragraph: “ We analyzed 162 ethograms and 27 of them could be identified..”

Line 230: “Manta 188”…maybe authors should change the way they name individuals. Manta N° 188, individual N° 188 or individual ID 188.

Figure 3: Authors should change the palette of colors, this figure has the same colors as the others figures, could be confusing.

Sup. Material: Table 2 and 4, authors should include “*” in significate p values to an easy read.

Discussion

Line 368: I found double space in several parts of the discussion. Authors should check double space throughout all the discussion.

I think the manuscript lack of final bullets showing the conclusions of the study. This could facilitate to the lector to close the manuscript reading in a better way.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

A very interesting paper about the possible effects that recreational divers may have on manta ray behavior. It is well written and thorough, but the description of the method is lacking, which makes it difficult to evaluate the soundness of the study. 

Please elaborate on the video collection of the diver-interactions, including dive sites/locations (roughly), time of day, and time of year (seasonal variances?). 

Were the diver interactions also recorded with a drone? Was it recorded right after the "natural state” and snorkeling recordings?

Was it a well-used dive site, or was it unusual for the mantas to experience divers here? 

Was it experienced divers, who are more calm in the water than less experienced divers, and how big were the group of divers? Were they stationary or moving?

Was the dive site a cleaning station, feeding grounds of high prey concentration, or was it chance encounters?

Were all 27 individuals part of the same overall population? Were they all juveniles? Same age group? In the introduction and discussion you mention that it was juvenile manta rays in a nursery habitat - please elaborate in the method. 

It is not described how objective 2, line 133, has been examined. Please elaborate on the method. How could you distinguish between the effect of the interaction and the personality (line 367)? Maybe a table with the individuals and their responses could help?

Maybe include some lines in the introduction about movement patterns, or other relevant ecology facts, on the early life of manta rays?

Could some of the observations be social communication (cephalic fin position fx.)?

Consider including some pictures/screenshots.

Personally, I would prefer a separate Conclusion paragraph. 

 

Other comments:

line 4: comma after Pate

line 218: Anova should be written ANOVA

line 426: Does this also include habitats where juvenile manta rays are not present?

line 461: …likelihood of juvenile mantas…

 

All in all, a very interesting study. If the method could be described more clearly, and this reveals no major concerns in the experimental design, I would recommend minor revisions.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is well-written, methodologically sound, and clearly presented. Only minor grammatical, typographical, and stylistic improvements are recommended.

Line 52–53:
Sentence: "it is crucial that to develop sustainable tourism initiatives, especially when imperiled species are involved."
➤ Suggestion: Remove “that” for clarity.
Revised: “It is crucial to develop sustainable tourism initiatives, especially when imperiled species are involved.”

Line 87–88:
Sentence: "they were unable to evaluate the behavior of undisturbed mantas."
➤ Suggestion: Clarify the reason — e.g., due to the footage being collected during active tourism operations.

Line 105–107:
Sentence: "Our specific objectives are to: 1) to quantify..."
➤ Suggestion: Remove the second “to” — grammatical redundancy.
Revised: “Our specific objectives are to: 1) quantify how the presence of divers affects…”

Line 131–135:
Sentence: "No noticeable changes in manta ray behavior were observed while lowering the drone altitude and other studies have found that drone altitude did not affect stingray behavior [32]."
➤ Suggestion: Split into two sentences for readability.
Revised: “No noticeable changes in manta ray behavior were observed while lowering the drone altitude. Other studies have found that drone altitude did not affect stingray behavior [32].”

Line 181–183:
Sentence: "It is worth noting that divers may have been present in the water, but not recorded as 'present' until they appeared in the video frame."
➤ Suggestion: This could be a potential source of bias—consider acknowledging it explicitly in the discussion.

Line 223–224:
Sentence: "𝛽0We choose a𝛽1 [34,36], and its successful application..."
➤ Suggestion: Typographical formatting issue with β characters.
Revised: “We chose β₀ and β₁ following [34,36] and their successful application…”

Line 372–376:
Sentence: "At the same time, researchers approach in small groups of one to two divers, with less disturbance (e.g. kicking and splashing) and know when to end an encounter if the animal is showing signs of stress."
➤ Suggestion: Split into two sentences for clarity.
Revised: “At the same time, researchers approach in small groups of one to two divers, with less disturbance (e.g., kicking and splashing). They also know when to end an encounter if the animal shows signs of stress.”

Line 385–387:
Sentence: "Compared to the observational methods utilized by [25], our study provides a unique opportunity..."
➤ Suggestion: Replace “utilized by” with “used in” for smoother academic tone.
Revised: “Compared to the observational methods used in [25], our study provides…”

Line 456–458:
Sentence: "including the inability to document subsurface behaviors and oceanographic data that may influence behavior, as well as reduced continuous observation due to flight duration restrictions."
➤ Suggestion: Consider rewording for smoother flow.
Revised: “These include the inability to document subsurface behaviors or oceanographic factors influencing behavior, and limitations on continuous observation due to drone flight duration.”

- Occasional long sentences could be broken up for clarity and readability.

- Ensure consistent use of terms — e.g., “manta rays” vs. “mantas.”

- Minor formatting inconsistencies in mathematical notation (e.g., β, γ, δ symbols) should be checked during typesetting.

Author Response

Please see the attachment

Author Response File: Author Response.pdf