Comparison of Target Strength of Pacific Herring (Clupea pallasii Valenciennes, 1847) from Ex-Situ Measurements and a Theoretical Model

Round 1

Reviewer 1 Report

GENERAL COMMENT:

The Target Strength comparison between Ex Situ Measurements and a Theoretical Model reported in this study is interesting and of value for fisheries management. The methodologies are appropriate and state-of-the art. The manuscript is well organized, with a good description of methodology and results.

However, there are some minor suggestion and correction to improve clarity and importance of the manuscript.

The authors should describe the aim and what is the gap of knowledge, this study aims to fill, describing them with more emphasis extending the introduction and the conclusion.

The manuscript would also greatly benefit from English proofreading and doublecheck to avoid Grammarly errors and defects (e.g., her-ring, measure-ments, ecc.).

TITLE:

Write on a correct way the name of species, in italic and with the author’s name (Clupea Pallasii, Valenciennes, 1847)

The title should be modified. I suggest:” Target Strength comparison of Pacific Herring (Clupea 2

Pallasii) from Ex Situ Measurements and a Theoretical Model”

INTRODUCTION:

LINE 25: As for title, the scientific name of the species should be written fully and correctly (Clupea Pallasii, Valenciennes, 1847)

LINE 45: As suggested in general comments, The authors should describe the aim and what is the gap of knowledge, this study aims to fill, describing them with more emphasis

MATERIALS AND METHODS:

LINE 49: What the authors means for “individually sampled”? Please explain

In addition, I strongly suggest shifting the number of specimens analyzed from results to materials and methods, in LINE 49

CONCLUSIONS:

As suggested in general comments, I strongly recommend emphasizing the gap of knowledge which this study aims to fil, introducing also the future purpose and the benefit in fisheries management which the results of this study could make.

Author Response

Thank you for providing these insights.

Reviewer 2 Report

In their original research article entitled: “Comparison of the Target Strength of Pacific Herring (Clupea pallasii) from Ex Situ Measurements and a Theoretical Model” Yoon et al. describe how they studied the target strength of 14 Pacific herring using x-ray and subsequent KRM backscatter modelling as well as in-situ measurements in a laboratory setting using 38 and 120 KHz echosounders. The authors also provide ex-situ target strength values for various tilt angles in an interesting and to my knowledge quite novel set-up. When the authors related the swimbladder radius to the GSI no significant relationship was found which may have had to do with the time of sampling.

Overall this is a very well-written and well-structured paper which provides important insights on the target strength of a commercially important species and thus makes a significant contribution to the field. I would have liked to see a larger sample size than 14 fish even though it is understandable that relatively elaborate set-up for the ex-situ measurements may have made this difficult. The only main point of concern I have is the method by which the herring were preserved. The authors write that the herring were frozen in seawater in plastic bottles. With the water becoming frozen in an enclosed space there is a risk that the swimbladder may have been compressed. If the authors can address this, I would suggest only minor edits:

1. In title: Clupea pallasii – “Pallasii” should not be capital P.
2. Throughout the texts words are separated by dashes – please go through the text and correct this, also I spotted 1-2 typos I think but nothing major
3. Clarify why the KRM model is used and mention any assumptions of the model
4. L70-72 and in Figure 1 boxes of “signal generator” and “video capture card”: this is the only section in the paper which could be explained better
5. Figure 1: picture of the acoustic system is not really important or relevant – I would be more interested to see a picture of the tank set-up or underwater footage of the fish being moored
6. L98-99: The text reads:” The TS from the KRM model was calculated at three frequencies, 38 and 120 kHz 98 (also used in the ex situ measurements), in the range of –90° to 90°, at 1° intervals. “ – what is meant with the three frequencies here?
7. Figure 3: The swim-bladder looks well defined and clear in the picture – I am wondering whether this was the case for all 14 fish. Including x-rays of all fish in Supplementary Information would be better practice for transparency.
8. In the discussion I think the authors should provide a perspective for future work – for instance to sample herring throughout the year to get a better idea of the GSI- swimbladder radius relationship

Author Response

Thank you for providing these insights.

Author Response File: Author Response.docx