Evidence for Initial Infestation by Mothocya parvostis (Isopoda: Cymothoidae) on Body Surface of Juvenile Japanese Halfbeak, Hyporhamphus sajori (Beloniformes: Hemiramphidae)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I reviewed the manuscript (MS) entitled “Evidence for initial infestation by Mothocya parvostis on body surface of juvenile Japanese halfbeak, Hyporhamphus sajori”, submitted as interesting images by Hiroki Fujita and Kentaro Kawai.

 

The present MS provides potential interesting information on Cymothoidae parasites collected from live fish in many areas of Japan, an area where these parasites have already been found. Overall, the MS is interesting, though some improvements are necessary. The authors provided a list of pictures that, in my opinion, should be better reported. In particular, figure 1b is not so clear, I would like to suggest the authors to provide better quality image. Moreover, I strongly suggest the authors to provide more particular related to the images submitted, just to add more particular to the description.

Furthermore, the absence of the line number did not allow an easy and quick evaluation of the MS.

No issues related to the language were found.

 

 

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

I reviewed the manuscript (MS) entitled “Evidence for initial infestation by Mothocya parvostis on body surface of juvenile Japanese halfbeak, Hyporhamphus sajori”, submitted as interesting images by Hiroki Fujita and Kentaro Kawai.

 

The present MS provides potential interesting information on Cymothoidae parasites collected from live fish in many areas of Japan, an area where these parasites have already been found. Overall, the MS is interesting, though some improvements are necessary. The authors provided a list of pictures that, in my opinion, should be better reported. In particular, figure 1b is not so clear, I would like to suggest the authors to provide better quality image. Moreover, I strongly suggest the authors to provide more particular related to the images submitted, just to add more particular to the description.

Furthermore, the absence of the line number did not allow an easy and quick evaluation of the MS.

No issues related to the language were found.

 

Response: Thank you for your helpful comments and suggestions. We do not have a replacement photo for Fig. 1b, but a higher resolution image will be provided at the time of publication. The figure captions have been added in more detail. Line numbers follow the style specified in this journal and are shown at the right margin of the manuscript.

 

Reviewer 2

 

 

Comments and Suggestions for Authors

Title

I recommend that the authors include basic taxonomic information in the title. Currently, the title mentions the scientific names of a parasite and a host, but it would be helpful to indicate that the study concerns a parasitic isopod and a fish host, to make the context clearer for a broader scientific audience. For example, including terms like “(Isopoda)” and “(Teleostei)” would enhance clarity and improve discoverability.

 

Response: Thank you for your helpful comments and suggestions. We revised the title as you pointed out.

 

Abstract

Line 12. In the Abstract, the host species is mentioned by its scientific name, but it is not clear that it is a marine fish. For clarity and broader accessibility, I recommend explicitly stating that the host is a marine fish and including its family name, at least. This will help readers unfamiliar with the species understand the biological context of the study.

Introduction

 

Response: Agreed and revised as your suggestion. 

 

Line 26. The authors state that the isopod uses a fish as its “final host.” This phrasing suggests that the parasite may have an indirect life cycle with one or more intermediate hosts. However, the life cycle of parasitic isopods is not clearly explained. I suggest briefly describing the complete life cycle of the species studied (direct or indirect) to clarify the host-parasite relationship and avoid confusion.

 

Response: Agreed and revised as your suggestion.  We mentioned about intermediate hosts in the text.

 

Line 29. The sentence suggests that the release of mancae, their development into males, and subsequent sex change to females all occur in July, which may not be accurate. If this process was observed specifically during that month in Inoue's study, please clarify that it refers to seasonal observations, and avoid implying that it only occurs in July. Otherwise, rephrase to reflect the general reproductive pattern more accurately.

 

Response: Inoue describe the timing of these phenomena, but because we do not agree with all of them, we deleted “July.”

 

Reviewer 3

 

Comments and Suggestions for Authors

The photographs provided, along with the species' DNA barcoding data, are useful for understanding an important stage in the life cycle of parasitic isopods: the primary site of invasion. Therefore, despite the photographs could be sharper, I believe that publishing this information is valuable.

However, the accompanying text could be improved.

 

Response: Thank you for your helpful comments and suggestions. We responded to each of the points raised as follows. 

 

The following remarks are listed in the order they appear in the text:

1. Line 23. According to the guidelines for this type of publication, sections such as "Introduction," etc., should not be included.

 

Response: Agreed and revised as your suggestion. 

 

 

1. Brief information on the practical significance of parasitic isopods as potential pathogens, especially for juvenile fish, should be added to justify why details of their life cycles are important.

 

Response: Agreed and revised as your suggestion (L30–31).

 

1. Lines 32–35. The reasoning is not logically presented. The statement “Among cymothoids, reports of cases such as Mothocya lineata (Miers, 1876), where males parasitize the gills and females inhabit the buccal cavity of the host, are extremely rare” is, first, given without a reference and, second, discusses differences in the places of parasitism between males and females. Therefore, it is unclear how this leads to a comparison with data on differences in localisation between juvenile and mature individuals of another species discussed in this study.            The order of presentation should be revised: the information on difference in the localisation of females and males should be moved to the previous paragraph, which describes the known data on the life cycles of these isopods, and only the information concerning the change in the habitat of juvenile individuals should be left in this paragraph: such a change has not been described for other species, therefore...

 

Response: In terms of the parasitic site changing depending on the growth stage, these two examples are the same phenomenon. The text was revised to make this clearer.

 

1. Line 43 – Start a new paragraph here.

 

Response: Agreed and revised as your suggestion. 

 

1. Lines 46, 69–71 – This information would be more logically placed after the sentence “The presence or absence of cymothoids was confirmed and photographed”, i.e.: “In this study, H. sajori juveniles were collected from the surface waters around oyster-culturing rafts off Ohkurokamishima Island, Etajima, Hiroshima Prefecture, Japan (see Kawai et al. [13]), on May 30, 2019, using paper cups. The presence or absence of cymothoids was confirmed and photographed. The cytochrome c oxidase subunit I (COI) sequence of the parasite was analyzed for species identification. DNA extraction and PCR amplification were performed following the protocol outlined by Fujita et al. [14]. The PCR product was sent to Eurofins Genomics (Tokyo, Japan) for sequencing using the dye terminator method.”

 

Response: Agreed and revised as your suggestion. 

 

1. The GenBank accession number (AN) should be added before publication, since obtaining it takes no more than a day.

 

Response: GenBank accession number was obtained and added to the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

Title

I recommend that the authors include basic taxonomic information in the title. Currently, the title mentions the scientific names of a parasite and a host, but it would be helpful to indicate that the study concerns a parasitic isopod and a fish host, to make the context clearer for a broader scientific audience. For example, including terms like “(Isopoda)” and “(Teleostei)” would enhance clarity and improve discoverability.

 

Abstract

Line 12. In the Abstract, the host species is mentioned by its scientific name, but it is not clear that it is a marine fish. For clarity and broader accessibility, I recommend explicitly stating that the host is a marine fish and including its family name, at least. This will help readers unfamiliar with the species understand the biological context of the study.

Introduction

Line 26. The authors state that the isopod uses a fish as its “final host.” This phrasing suggests that the parasite may have an indirect life cycle with one or more intermediate hosts. However, the life cycle of parasitic isopods is not clearly explained. I suggest briefly describing the complete life cycle of the species studied (direct or indirect) to clarify the host-parasite relationship and avoid confusion.

 

Line 29. The sentence suggests that the release of mancae, their development into males, and subsequent sex change to females all occur in July, which may not be accurate. If this process was observed specifically during that month in Inoue's study, please clarify that it refers to seasonal observations, and avoid implying that it only occurs in July. Otherwise, rephrase to reflect the general reproductive pattern more accurately.

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

I reviewed the manuscript (MS) entitled “Evidence for initial infestation by Mothocya parvostis on body surface of juvenile Japanese halfbeak, Hyporhamphus sajori”, submitted as interesting images by Hiroki Fujita and Kentaro Kawai.

 

The present MS provides potential interesting information on Cymothoidae parasites collected from live fish in many areas of Japan, an area where these parasites have already been found. Overall, the MS is interesting, though some improvements are necessary. The authors provided a list of pictures that, in my opinion, should be better reported. In particular, figure 1b is not so clear, I would like to suggest the authors to provide better quality image. Moreover, I strongly suggest the authors to provide more particular related to the images submitted, just to add more particular to the description.

Furthermore, the absence of the line number did not allow an easy and quick evaluation of the MS.

No issues related to the language were found.

 

Response: Thank you for your helpful comments and suggestions. We do not have a replacement photo for Fig. 1b, but a higher resolution image will be provided at the time of publication. The figure captions have been added in more detail. Line numbers follow the style specified in this journal and are shown at the right margin of the manuscript.

 

Reviewer 2

 

 

Comments and Suggestions for Authors

Title

I recommend that the authors include basic taxonomic information in the title. Currently, the title mentions the scientific names of a parasite and a host, but it would be helpful to indicate that the study concerns a parasitic isopod and a fish host, to make the context clearer for a broader scientific audience. For example, including terms like “(Isopoda)” and “(Teleostei)” would enhance clarity and improve discoverability.

 

Response: Thank you for your helpful comments and suggestions. We revised the title as you pointed out.

 

Abstract

Line 12. In the Abstract, the host species is mentioned by its scientific name, but it is not clear that it is a marine fish. For clarity and broader accessibility, I recommend explicitly stating that the host is a marine fish and including its family name, at least. This will help readers unfamiliar with the species understand the biological context of the study.

Introduction

 

Response: Agreed and revised as your suggestion. 

 

Line 26. The authors state that the isopod uses a fish as its “final host.” This phrasing suggests that the parasite may have an indirect life cycle with one or more intermediate hosts. However, the life cycle of parasitic isopods is not clearly explained. I suggest briefly describing the complete life cycle of the species studied (direct or indirect) to clarify the host-parasite relationship and avoid confusion.

 

Response: Agreed and revised as your suggestion.  We mentioned about intermediate hosts in the text.

 

Line 29. The sentence suggests that the release of mancae, their development into males, and subsequent sex change to females all occur in July, which may not be accurate. If this process was observed specifically during that month in Inoue's study, please clarify that it refers to seasonal observations, and avoid implying that it only occurs in July. Otherwise, rephrase to reflect the general reproductive pattern more accurately.

 

Response: Inoue describe the timing of these phenomena, but because we do not agree with all of them, we deleted “July.”

 

Reviewer 3

 

Comments and Suggestions for Authors

The photographs provided, along with the species' DNA barcoding data, are useful for understanding an important stage in the life cycle of parasitic isopods: the primary site of invasion. Therefore, despite the photographs could be sharper, I believe that publishing this information is valuable.

However, the accompanying text could be improved.

 

Response: Thank you for your helpful comments and suggestions. We responded to each of the points raised as follows. 

 

The following remarks are listed in the order they appear in the text:

1. Line 23. According to the guidelines for this type of publication, sections such as "Introduction," etc., should not be included.

 

Response: Agreed and revised as your suggestion. 

 

 

1. Brief information on the practical significance of parasitic isopods as potential pathogens, especially for juvenile fish, should be added to justify why details of their life cycles are important.

 

Response: Agreed and revised as your suggestion (L30–31).

 

1. Lines 32–35. The reasoning is not logically presented. The statement “Among cymothoids, reports of cases such as Mothocya lineata (Miers, 1876), where males parasitize the gills and females inhabit the buccal cavity of the host, are extremely rare” is, first, given without a reference and, second, discusses differences in the places of parasitism between males and females. Therefore, it is unclear how this leads to a comparison with data on differences in localisation between juvenile and mature individuals of another species discussed in this study.            The order of presentation should be revised: the information on difference in the localisation of females and males should be moved to the previous paragraph, which describes the known data on the life cycles of these isopods, and only the information concerning the change in the habitat of juvenile individuals should be left in this paragraph: such a change has not been described for other species, therefore...

 

Response: In terms of the parasitic site changing depending on the growth stage, these two examples are the same phenomenon. The text was revised to make this clearer.

 

1. Line 43 – Start a new paragraph here.

 

Response: Agreed and revised as your suggestion. 

 

1. Lines 46, 69–71 – This information would be more logically placed after the sentence “The presence or absence of cymothoids was confirmed and photographed”, i.e.: “In this study, H. sajori juveniles were collected from the surface waters around oyster-culturing rafts off Ohkurokamishima Island, Etajima, Hiroshima Prefecture, Japan (see Kawai et al. [13]), on May 30, 2019, using paper cups. The presence or absence of cymothoids was confirmed and photographed. The cytochrome c oxidase subunit I (COI) sequence of the parasite was analyzed for species identification. DNA extraction and PCR amplification were performed following the protocol outlined by Fujita et al. [14]. The PCR product was sent to Eurofins Genomics (Tokyo, Japan) for sequencing using the dye terminator method.”

 

Response: Agreed and revised as your suggestion. 

 

1. The GenBank accession number (AN) should be added before publication, since obtaining it takes no more than a day.

 

Response: GenBank accession number was obtained and added to the manuscript.

Reviewer 3 Report

Comments and Suggestions for Authors

The photographs provided, along with the species' DNA barcoding data, are useful for understanding an important stage in the life cycle of parasitic isopods: the primary site of invasion. Therefore, despite the photographs could be sharper, I believe that publishing this information is valuable.

However, the accompanying text could be improved.

The following remarks are listed in the order they appear in the text:

1. Line 23. According to the guidelines for this type of publication, sections such as "Introduction," etc., should not be included.
2. Brief information on the practical significance of parasitic isopods as potential pathogens, especially for juvenile fish, should be added to justify why details of their life cycles are important.
3. Lines 32–35. The reasoning is not logically presented. The statement “Among cymothoids, reports of cases such as Mothocya lineata (Miers, 1876), where males parasitize the gills and females inhabit the buccal cavity of the host, are extremely rare” is, first, given without a reference and, second, discusses differences in the places of parasitism between males and females. Therefore, it is unclear how this leads to a comparison with data on differences in localisation between juvenile and mature individuals of another species discussed in this study.            The order of presentation should be revised: the information on difference in the localisation of females and males should be moved to the previous paragraph, which describes the known data on the life cycles of these isopods, and only the information concerning the change in the habitat of juvenile individuals should be left in this paragraph: such a change has not been described for other species, therefore...
4. Line 43 – Start a new paragraph here.
5. Lines 46, 69–71 – This information would be more logically placed after the sentence “The presence or absence of cymothoids was confirmed and photographed”, i.e.: “In this study, H. sajori juveniles were collected from the surface waters around oyster-culturing rafts off Ohkurokamishima Island, Etajima, Hiroshima Prefecture, Japan (see Kawai et al. [13]), on May 30, 2019, using paper cups. The presence or absence of cymothoids was confirmed and photographed. The cytochrome c oxidase subunit I (COI) sequence of the parasite was analyzed for species identification. DNA extraction and PCR amplification were performed following the protocol outlined by Fujita et al. [14]. The PCR product was sent to Eurofins Genomics (Tokyo, Japan) for sequencing using the dye terminator method.”
6. The GenBank accession number (AN) should be added before publication, since obtaining it takes no more than a day.

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

I reviewed the manuscript (MS) entitled “Evidence for initial infestation by Mothocya parvostis on body surface of juvenile Japanese halfbeak, Hyporhamphus sajori”, submitted as interesting images by Hiroki Fujita and Kentaro Kawai.

 

The present MS provides potential interesting information on Cymothoidae parasites collected from live fish in many areas of Japan, an area where these parasites have already been found. Overall, the MS is interesting, though some improvements are necessary. The authors provided a list of pictures that, in my opinion, should be better reported. In particular, figure 1b is not so clear, I would like to suggest the authors to provide better quality image. Moreover, I strongly suggest the authors to provide more particular related to the images submitted, just to add more particular to the description.

Furthermore, the absence of the line number did not allow an easy and quick evaluation of the MS.

No issues related to the language were found.

 

Response: Thank you for your helpful comments and suggestions. We do not have a replacement photo for Fig. 1b, but a higher resolution image will be provided at the time of publication. The figure captions have been added in more detail. Line numbers follow the style specified in this journal and are shown at the right margin of the manuscript.

 

Reviewer 2

 

 

Comments and Suggestions for Authors

Title

I recommend that the authors include basic taxonomic information in the title. Currently, the title mentions the scientific names of a parasite and a host, but it would be helpful to indicate that the study concerns a parasitic isopod and a fish host, to make the context clearer for a broader scientific audience. For example, including terms like “(Isopoda)” and “(Teleostei)” would enhance clarity and improve discoverability.

 

Response: Thank you for your helpful comments and suggestions. We revised the title as you pointed out.

 

Abstract

Line 12. In the Abstract, the host species is mentioned by its scientific name, but it is not clear that it is a marine fish. For clarity and broader accessibility, I recommend explicitly stating that the host is a marine fish and including its family name, at least. This will help readers unfamiliar with the species understand the biological context of the study.

Introduction

 

Response: Agreed and revised as your suggestion. 

 

Line 26. The authors state that the isopod uses a fish as its “final host.” This phrasing suggests that the parasite may have an indirect life cycle with one or more intermediate hosts. However, the life cycle of parasitic isopods is not clearly explained. I suggest briefly describing the complete life cycle of the species studied (direct or indirect) to clarify the host-parasite relationship and avoid confusion.

 

Response: Agreed and revised as your suggestion.  We mentioned about intermediate hosts in the text.

 

Line 29. The sentence suggests that the release of mancae, their development into males, and subsequent sex change to females all occur in July, which may not be accurate. If this process was observed specifically during that month in Inoue's study, please clarify that it refers to seasonal observations, and avoid implying that it only occurs in July. Otherwise, rephrase to reflect the general reproductive pattern more accurately.

 

Response: Inoue describe the timing of these phenomena, but because we do not agree with all of them, we deleted “July.”

 

Reviewer 3

 

Comments and Suggestions for Authors

The photographs provided, along with the species' DNA barcoding data, are useful for understanding an important stage in the life cycle of parasitic isopods: the primary site of invasion. Therefore, despite the photographs could be sharper, I believe that publishing this information is valuable.

However, the accompanying text could be improved.

 

Response: Thank you for your helpful comments and suggestions. We responded to each of the points raised as follows. 

 

The following remarks are listed in the order they appear in the text:

1. Line 23. According to the guidelines for this type of publication, sections such as "Introduction," etc., should not be included.

 

Response: Agreed and revised as your suggestion. 

 

 

1. Brief information on the practical significance of parasitic isopods as potential pathogens, especially for juvenile fish, should be added to justify why details of their life cycles are important.

 

Response: Agreed and revised as your suggestion (L30–31).

 

1. Lines 32–35. The reasoning is not logically presented. The statement “Among cymothoids, reports of cases such as Mothocya lineata (Miers, 1876), where males parasitize the gills and females inhabit the buccal cavity of the host, are extremely rare” is, first, given without a reference and, second, discusses differences in the places of parasitism between males and females. Therefore, it is unclear how this leads to a comparison with data on differences in localisation between juvenile and mature individuals of another species discussed in this study.            The order of presentation should be revised: the information on difference in the localisation of females and males should be moved to the previous paragraph, which describes the known data on the life cycles of these isopods, and only the information concerning the change in the habitat of juvenile individuals should be left in this paragraph: such a change has not been described for other species, therefore...

 

Response: In terms of the parasitic site changing depending on the growth stage, these two examples are the same phenomenon. The text was revised to make this clearer.

 

1. Line 43 – Start a new paragraph here.

 

Response: Agreed and revised as your suggestion. 

 

1. Lines 46, 69–71 – This information would be more logically placed after the sentence “The presence or absence of cymothoids was confirmed and photographed”, i.e.: “In this study, H. sajori juveniles were collected from the surface waters around oyster-culturing rafts off Ohkurokamishima Island, Etajima, Hiroshima Prefecture, Japan (see Kawai et al. [13]), on May 30, 2019, using paper cups. The presence or absence of cymothoids was confirmed and photographed. The cytochrome c oxidase subunit I (COI) sequence of the parasite was analyzed for species identification. DNA extraction and PCR amplification were performed following the protocol outlined by Fujita et al. [14]. The PCR product was sent to Eurofins Genomics (Tokyo, Japan) for sequencing using the dye terminator method.”

 

Response: Agreed and revised as your suggestion. 

 

1. The GenBank accession number (AN) should be added before publication, since obtaining it takes no more than a day.

 

Response: GenBank accession number was obtained and added to the manuscript.