New Record of Geoduck Clam Collected from the East Coast of South Korea and Its Reproductive Characteristics
Round 1
Reviewer 1 Report
This study reports the discovery of geoduck clams in South Korea and describes their complete mitochondrial genome as well as their reproduction. The work is very complete, using adequate tools and methodologies and obtaining relevant information for geoduck clams in the region.
Reviewing the document, my only concern is about some values of the size of the clams, since they are too large and exceed the commonly reported values. The rest of the document I find well written with a good organization of information. Here are some specific observations:
Abstract
Line 20. It is P. globosa
Line 29. Geoduck clam is already in the title, you can change it to a different keyword to widen the range of impact
Table 1. Check the scientific names; Panopea abrupta, P. globosa
Figure 3 (d). The reference line indicates 100 mm (10 cm), but it seems that it does not correspond to the real size of the clam (too big!), please check the scale
Lines 153-155. I see the measurements reported and they seem too big for clams when I convert them to centimeters: postvalvular extension is 71 cm long, siphons; length of up to 96 cm, and a height of up to 59 cm (particularly this last one). Please check the reported values since in Table 3 the largest clams are around 136 mm.
Line 158. Apparently, the automatic corrector changes P. globosa to P. globose, please verify throughout the document.
Line 224. Include mm: “Table 3. Number and size ranges (mm)………”
Lines 249 and 254. I suggest changing photomicrographs for images
Author Response
Reviewer1:
Comments and Suggestions for Authors
This study reports the discovery of geoduck clams in South Korea and describes their complete mitochondrial genome as well as their reproduction. The work is very complete, using adequate tools and methodologies and obtaining relevant information for geoduck clams in the region. Reviewing the document, my only concern is about some values of the size of the clams, since they are too large and exceed the commonly reported values. The rest of the document I find well written with a good organization of information. Here are some specific observations:
-> Thank you for your comments According to your comments, we have revised the manuscript and incorporated changes as suggested by your comments. The revisions are marked in red in the revised manuscript and the details have been revised as below, as your comments.
Abstract
1) Line 20. It is P. globosa
Response: Corrected.
2) Line 29. Geoduck clam is already in the title, you can change it to a different keyword to widen the range of impact
Response: Thank you for your comment. We have modified according to the reviewer’s suggestion in the revised manuscript.
3) Table 1. Check the scientific names; Panopea abrupta, P. globosa
Response: Corrected.
4) Figure 3 (d). The reference line indicates 100 mm (10 cm), but it seems that it does not correspond to the real size of the clam (too big!), please check the scale
Response: We apologize for the confusion. We have corrected in the revised manuscript.
5) Lines 153-155. I see the measurements reported and they seem too big for clams when I convert them to centimeters: postvalvular extension is 71 cm long, siphons; length of up to 96 cm, and a height of up to 59 cm (particularly this last one). Please check the reported values since in Table 3 the largest clams are around 136 mm.
Response: Corrected.
6) Line 158. Apparently, the automatic corrector changes P. globosa to P. globose, please verify throughout the document.
Response: Corrected.
7) Line 224. Include mm: “Table 3. Number and size ranges (mm)………”
Response: Thank you for your comments. We have corrected in the revised manuscript.
8) Lines 249 and 254. I suggest changing photomicrographs for images
Response: We have provided the original image. However, this is the limit in original image as they have been edited to fit the journal format. I hope you will consider this matter. Thank you.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors Jeonghoon Han, Jong Guk Kim, O-Nam Kwon, Young-Ung Choi have conducted an advanced and practical experimental study for determining the complete mitochondrial genome of a Panopea sp. specimen and investigating its seasonal reproductive pattern.
The present paper describes exhaustively the materials and methods involved in the experiment. However, I am not an expert in biological sciences, so I cannot evaluate properly the methods and results presented in this paper.
The manuscript is well organized and well written. The strong points of this paper are the novelty of the investigation for Panopea sp. in South Korea, the clarity of the exposition, and the concise nature of the paper. The weak point for my point of view is the lack of species-level identification of the specimens, which is really important in this type of work, so the main suggestion is to identified the studied species as reported in other works of the same topic (Bisbal-Pardo et al. 2016, a & b; Yu et al., 2016). If the Authors are sure about that the specimens belong to a new species, it is very important to highlight this point and think about establish a new species. It is a pity to write that is a new species and then only say “Panopea sp.”, I think.
In addition, only few small suggestions:
Line 84: “Figure 2” I think, not 1
Line 85: Panopea in Italic
Table 1: Panopea abrupta (Please, check in the entire paper and literature that the name is correct)
Line 180: Panopea in Italic
Line 181: Panopea in Italic
Line 190: I think that the citation 3 is erroneous. The cited paper is not mentioning fossil Panopea abrupta.
Line 254: Panopea in Italic
Line 267: Panopea abbreviata
Line 267: shows
I suggest publication after minor revision and after a review regarding English and biological aspects of which I am not an expert.
Author Response
Reviewer2:
Comments and Suggestions for Authors
The authors Jeonghoon Han, Jong Guk Kim, O-Nam Kwon, Young-Ung Choi have conducted an advanced and practical experimental study for determining the complete mitochondrial genome of a Panopea sp. specimen and investigating its seasonal reproductive pattern. The present paper describes exhaustively the materials and methods involved in the experiment. However, I am not an expert in biological sciences, so I cannot evaluate properly the methods and results presented in this paper. The manuscript is well organized and well written. The strong points of this paper are the novelty of the investigation for Panopea sp. in South Korea, the clarity of the exposition, and the concise nature of the paper. The weak point for my point of view is the lack of species-level identification of the specimens, which is really important in this type of work, so the main suggestion is to identified the studied species as reported in other works of the same topic (Bisbal-Pardo et al. 2016, a & b; Yu et al., 2016). If the Authors are sure about that the specimens belong to a new species, it is very important to highlight this point and think about establish a new species. It is a pity to write that is a new species and then only say “Panopea sp.”, I think.
-> Thank you for your comments According to your comments, we have revised the manuscript and incorporated changes as suggested by your comments. The revisions are marked in red in the revised manuscript and the details have been revised as below, as your comments.
Response: We agreed that your comments. To date, the genus Panopea includes 10 extant and 13 extinct species. To establish a new species bivalve species, it is essential to compare internal structures such mantle, heart, gills, etc. However, information on these morphologies of the other congeners is poor as yet. Thus, this study is focused on the species identification based on complete mitochondrial DNA and brief morphological characterization. Pending a revision of morphology of Panopea species, we decided to report this Korean species as Panopea sp. Thus, we expect that reviewer try to focus on the novelty of experimental design and the adequate result of this study. Thank you.
In addition, only few small suggestions:
1) Line 84: “Figure 2” I think, not 1
Response: Corrected.
2) Line 85: Panopea in Italic
Response: Corrected.
3) Table 1: Panopea abrupta (Please, check in the entire paper and literature that the name is correct)
Response: Corrected.
4) Line 180: Panopea in Italic
Response: Corrected.
5) Line 181: Panopea in Italic
Response: Corrected.
6) Line 190: I think that the citation 3 is erroneous. The cited paper is not mentioning fossil Panopea abrupta.
Response: We apologize for the confusion. We have corrected in the revised manuscript.
7) Line 254: Panopea in Italic
Response: Corrected.
8) Line 267: Panopea abbreviata
Response: Corrected.
9) Line 267: shows
Response: Corrected.
I suggest publication after minor revision and after a review regarding English and biological aspects of which I am not an expert.
Response: Thank you for your comments and great suggestion.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript is well written, and all the data was discussed related to the monthly sampling, sea surface temperature, and reproductive cycle. However, some improvement are neeed. Firstly, The study did not mention any ethical committe invovled or it was not needed? Secondly, what happened to the collected clams after they have been used for histology and other experiment? Thirdy, please provide more details on how author randonly collected the clams in various areas? the choosen areas was not affected the reproductive stage of the clams? Finally, please add more referece in the discussion section.
Author Response
Reviewer3:
Comments and Suggestions for Authors
The manuscript is well written, and all the data was discussed related to the monthly sampling, sea surface temperature, and reproductive cycle. However, some improvement is need.
-> Thank you for your comments According to your comments, we have revised the manuscript and incorporated changes as suggested by your comments. The revisions are marked in red in the revised manuscript and the details have been revised as below, as your comments.
Firstly, the study did not mention any ethical committee involved or it was not needed?
Response: In Korea, according to the Animal Protection Act, in the case of vertebrate animals, a ethical committee must be operated by classifying them (Common class B - E). However, invertebrates or dead individuals (Common class A) are not considered. However, even for invertebrates, if the journal requests a review number, it can be reviewed and given a review number.
Secondly, what happened to the collected clams after they have been used for histology and other experiment?
Response: In the Act on Laboratory Animals, laboratory animals are subject to the Waste Management Act. However, according to the Waste Management Act, only when special management is required for health and environmental protection, it must be treated as medical waste as prescribed by the Presidential Decree, but shellfish testing sites are not included in medical waste generating institutions. Therefore, it is treated the same as general food waste, not special waste as mice. In case of morphological characteristics analysis, after the experiment is completed, samples were deposited at the Honam National Institute of Biological Resources (HNIBR).
Thirdly, please provide more details on how author randomly collected the clams in various areas?
Response: These clams are buried 50-80 cm deep on the sea bottom, exposing their siphons only. In this case, the diver digs the surrounding mud by high-pressure sprayer and catches them one by one. While keeping the clams caught in this way in a land-based sea-water tank with sand, they are using in experiments such as egg spawning.
The chosen areas was not affected the reproductive stage of the clams? Finally, please add more reference in the discussion section.
Response: Thank you very much for your comments. In bivalve species from temperate regions, spawning well as gonad growth and gematogensis, are correlated to changes in ambient seawater temperature (Giese and Pierce, 1979). In burrowing species such as Panopea abbeviata, P. japonica, Protothaca antiqua, Ensis macha, these species have the protracted spawning season or two periods of spawning seaons (Borozon, 1989; Barón et al., 2004; Molen et al., 2007; Zhao et al., 2022). Regarding this spawning activity patterns, Molen et al. (2007) suggested that the burrowing species with lives buried deep in soft sediments and thermal stability inside the sediment could be the explanation for the above patterns of protracted spawning period. Thus, in our study, geoduck clam is a burrowing species, and the protracted spawning season is seems due to thermal stability inside temperature conditions in sediment. However, we acknowledge that some expressions may be overinterpreted in Line268-Line169. Therefore the manuscript has been amended and added more references as follows;
“In previous studies, the maturing stages of male P. generosa and P. japonica were observed every month [33, 34]. Moreover, a previous study reported that P. abbreviate populations in northern Argentinean Patagonia show a protected spawning season with no clear pattern of spawning peaks and suggested that P. abbreviata live in environments less affected by temperature changes, such~”
à “In previous studies, burrowing species such as Panopea abbeviata, P. japonica, Protothaca antiqua, and Ensis macha, these species have a protracted spawning season or two periods of spawning seasons [28, 33, 34, 35, 36]. Moreover, a previous study reported that P. abbreviate populations in northern Argentinean Patagonia show a protected spawning season with no clear pattern of spawning peaks and suggested that P. abbreviata live in thermal stability environments, such~”
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
the article has been improved
