Suitability Assessment of Fish Habitat in a Data-Scarce River

Round 1

Reviewer 1 Report

This paper reports on a field study and subsequent GIS and modeling analysis of water quality and quantity in a 42-km river reach, including a hydraulic model and a habitat suitability model. In its current state, there is not enough description in the paper for a reader to be able to duplicate the study in any of its steps, further discussion of related work needs to be included, and the results of the work need to be discussed more in depth.

The second sentence of the paper takes an incorrectly strong stance; DO, COD, and BOD are by no means the sole "basic parameters" of river water quality, though they are of course important ones. The first paragraph tries to do too much; instead of a sentence introducing everything the paper will present later, a focused introduction on water quality and fish habitat would better direct the reader's attention. Every element that is introduced in the current paragraph should have an entire paragraph with relevant background information devoted to it instead of a single sentence. The second paragraph contains more appropriate information for an introduction, and the authors should describe the fish species of interest (why it was chosen and other important things about its life history and water quality needs).

The first paragraph of the methods section is an unnecessary overview that should be described in a separate section for each step (a section for the field survey, one for the Delft3D model, one for PHABSIM).

The description of the spatial extent of the field survey is good, but the temporal description needs to be improved. The sampling parameters are discussed too quickly and are mixed together with bathymetric data. Instead of discussing the survey as "datasets" the authors should just describe the field campaign in more depth. Did the authors measure velocity themselves?

Section 3.2 describes equations related to the numeric model but not the authors' setup of the model.

Is figure 7 measured or modeled? This step needs to be described more in depth.

In Table 1, what is the Spatial column? A difference or error value for the different parameters measured vs modeled should be included in the table for quick reference by the reader. The model and parameter that Table 2 is describing should be included in the Table 2 title/description.

Dissolved oxygen levels of 3 mg/L are generally considered very low and point to problems in a river, and values of 2 or below are highly problematic for aquatic life. The implications of this DO for the fish of interest should be discussed further. The nitrogen and phosphorous measurements should be visualized.

The process leading up to the creation of Figure 12 should be further discussed.

This paper combines an immense amount of work. The authors might be better served by splitting it into two publications: the first describing the field campaign (especially if it is truly a novel one for the area, which the authors should ensure is the case), conducting an interpolation, and describing patterns and potential restoration efforts, and the second paper addressing the modeling efforts. 

There are a few minor typos that should be fixed, though it is beyond the scope of this review to list every edit (e.g., on line 6, there is a semicolon instead of a paranthesis; later on in the first large paragraph, there is a space between the parenthesis and text, section 3.3's title is not capitalized, etc.).

This research will potentially be very interesting to readers, but the paper requires restructuring and much more description of the methods, results, discussion, and related work.

Author Response

Thank you very much for your comments. Please see the attachments.

Author Response File: Author Response.docx

Reviewer 2 Report

Despite the interesting and valuable results presented in the manuscript, the authors did not prepare manuscript according to Instructions for Authors for this journal. The title suggest that main topic is fish habitat, but the complete research is related to water quality parameters, and only small part is about habitat suitability for fish species Labeo rohita. The scientific name of the species is not written correctly according to zoological nomenclature Code. The references in the text must be pointed by numbers in square brackets, not writing e.g. (Chen et al., 2012)., and complete chapter References is written in wrong way. This is not a technical issues but indicates a lack of seriousness by the authors. 

Author Response

Thank you very much for your comments. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

This study validate a hydrodynamic model. An interpolation technique, i.e. inverse distance weighted (IDW), generates a map using ArcGIS software to determine the spatial and temporal analysis of DO in the river. The Delft3D model was applied to simulate the flow and representative parameters of the water quality of the Karnafuli River to establish a relationship between the flow of the river and the water quality. This involved demonstrating the quality of the habitat for Labeo rohita (Rohu fish) in the river. What highlights its importance to be replicable in other areas.

It is necessary to improve the portability of the tests carried out in the laboratory for the water quality parameters, in order to validate their application. It is important to mention in the conclusion.

Author Response

Thank you very much for your comments. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 4 Report

Article Suitability assessment of fish habitat in a data-scarce river

Aysha Akter  Md. Redwoan Toukir  and Ahammed Dayem

abstract

1.       The abstract can be improved by highlighting the specific need for the analysis (such as interpolation (IDW)). Less important info can be removed from the abstract to make some room for more crucial information.

2.       State the specific fish sp’s name in the abstract.

3.       The abstract is missing the results part.

 

Introduction

1.       It is suggested to split the facts by component in a separate paragraph rather than lump the discussions in one paragraph especially when there is no continuity or order flow for the discussion points.

 

Materials and methodology

1.       Since many approaches and analyses/models are used in the study, it is suggested to split the detailed explanation on each into separate paragraphs. The current state of methodology presentation is confusing and insufficient.

2.       The water quality parameter selection (as highlighted in Figure 1) needs to be justified and tally with the earlier sections (eg: in abstract and in introduction section). Why these parameters are chosen and how it is more significant in contributing towards the overall fish habitat suitability analysis compared to the others?

3.       Detail information on the study area (Karnafuli River) is lacking. Crucial input such as the hydrologic properties, overall catchment characteristics, whether there is any water abstraction or regulation along the river or not, and other information on the current river properties could enrich the section.

4.       Labels on Figure 2b are not clear. The map is not acceptable in its current form, due to the lack of standard elements in a scientific map.

5.       The exact procedures on the bathrimetry survey are missing, including the secondary reference from CPA for validation.

6.       The hourly measurement of DO using portable DO meter was done for the 90 sampling sites across the river stretch? How the measurement timing was done at each sampling points to ensure the DO variability is in a comparable range, given the fact that the DO concentration varies depending on the diurnal pattern of the day. No information on how the measurement was done, considering the stratified sampling approach at different water column layer could lengthen the exact time needed at each sampling point.

7.       Why would the DO being retested in the lab while the in situ measurements were already done at site (in situ) using portable DO meter?

8.       State the method’s name and procedure number according to APHA standard method or nitrate and phosphate tests rather than stating the reagents used in the analysis.

9.       The scale in the x-axis and y-axis in Figure 3 and Figure 4 are inconsistent.

10.   Figure 5 might not relevant to the context of explanation. It is more important to state the significance of such interpolation analysis to be done in relating the tested components of the study.

11.   Revisit the writing style for the scientific name of the fish species.

12.   No justification on the fish species selection for the study  (significant of the species towards the socioeconomic, conservation or any other values). Whether it is native and suitable to be used as indicator species throughout the entire stretch of the river.

13.   It is suggested to put the standard deviation in the observed values in Table 1 (page 9), to support the explanation for the simulated values.

14.   The standard deviation values for most sampling stations in Table 3 are mostly in extreme range of deviation, therefore it is suggested to conduct a distribution data test for extreme/unusual values detection, otherwise it might not convincing to generalize the tds pattern due to this wide range of variation.

15.   The grid labels in Figure 9 are illegible.

16.   It is suggested to mark/point the said industrial area (Kalurghat heavy industry area) within the plot in Figure 10, and to be supported with relevant reference on why those activities contribute to higher DO content in the water? Was it coincidence with the hydrologic and hydraulic properties of the river section at that particular river reach, or was it influenced by the industrial activities itself? The discussion is not clear.

17.   The hydrologic properties including the flow regime across the longitudinal stretch of the river could be incorporated into the discussion. This is especially critical to support on certain higher n lower trend of particular parameters (eg: DO), given the fact that the DO concentration is governed majorly by the flow characteristics (to support the discussion in last paragraph page 14)

18.   The tidal activity and its pattern is missing in the discussion or in the results

Conclusion

The overall conclusion could be improved to address the need of the study in its applicability context.

 

Reference

Please standardize the reference list and writing style.

 

 

 

 

Author Response

Thank you very much for your comments. Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This paper still requires reorganization and rewriting. There have been thousands of studies using hydraulic and habitat modeling such as PHABSIM for fish, and many of them are freely available from the past few years; recent studies should be described and cited, preferably from rivers similar to the one being studied and with relevant fish species. The fish species needs to be described, including its life history, distribution, dissolved oxygen requirements, and why it is of interest.

The methodology must be rewritten to the degree that it could be duplicated by other researchers. The methods sections should be organized similar to other papers that describe field work, including time periods/dates of the field campaign (including how often the sampling happened, or if it was just once per site). Relevant weather data should be discussed (i.e., was it a representative year, much wetter or drier than usual, etc.). Additional information should be included about why only some of the 90 sites were selected for lab work.

The modeling sections should also be organized similar to existing papers that conduct modeling. Such questions that need to be addressed are the calibration, validation, error, and confidence bounds related to each set of models created, especially since model results are then fed into other models. The authors must address the question of how accurate any of the results are. The tidal influence section must be expanded upon because there is not enough information presented in the paper to draw any sort of conclusion.

Author Response

Response to Reviewer 1 Comments

 

Comments and Suggestions for Authors

This paper still requires reorganization and rewriting. There have been thousands of studies using hydraulic and habitat modeling such as PHABSIM for fish, and many of them are freely available from the past few years; recent studies should be described and cited, preferably from rivers similar to the one being studied and with relevant fish species. The fish species needs to be described, including its life history, distribution, dissolved oxygen requirements, and why it is of interest.

 

Response 1: Revised with the recent information on hydraulic modeling and similar fish studies.

 

The methodology must be rewritten to the degree that it could be duplicated by other researchers. The methods sections should be organized similar to other papers that describe field work, including time periods/dates of the field campaign (including how often the sampling happened, or if it was just once per site). Relevant weather data should be discussed (i.e., was it a representative year, much wetter or drier than usual, etc.). Additional information should be included about why only some of the 90 sites were selected for lab work.

 

Response 2: Changed

 

The modeling sections should also be organized similar to existing papers that conduct modeling. Such questions that need to be addressed are the calibration, validation, error, and confidence bounds related to each set of models created, especially since model results are then fed into other models. The authors must address the question of how accurate any of the results are. The tidal influence section must be expanded upon because there is not enough information presented in the paper to draw any sort of conclusion.

 

Response 3: Changed

Author Response File: Author Response.docx

Reviewer 2 Report

All comments and suggestions to author are given  in the pdf document of the second version of the submitted manuscript. The authors still have to re-arrange the manuscript according to Instructions for Authors. Check the latest published paper in the journal Hydrology and see how it is done in proper manner. The autors still have to make significant corrections in the manuscript.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

 

All comments and suggestions to author are given  in the pdf document of the second version of the submitted manuscript. The authors still have to re-arrange the manuscript according to Instructions for Authors. Check the latest published paper in the journal Hydrology and see how it is done in proper manner. The autors still have to make significant corrections in the manuscript.

Our responses as below:

 

1. Scarce – updated
2. font size !! -corrected
3. All reference in the paper must be written by number in square brackets, according to Instructions for Author. Check the latest published papers in the journal Hydrology – updated accordingly
4. Page 2: Add some notes about Labeo rohita fish species. Readers across the world are not familliar with this fish. So, add some zoological characteristics, to which family of fish it belongs, is it native, endangered species....included
5. rohita – corrected
6. specify which three stages- specified
7. Reverse the order of diagrams according to description given for Figure 5. Station 45 (up), Station 50 (below): Reversed
8. rohita – corrected
9. Field Test- corrected
10. not in bold – updated
11. Variations– updated
12. specify value, repet it !-revised
13. correct 6.5 to 7 (according to range given in legend of Figure 8)- corrected
14. Correct number of subtitle 4.2 to 4.3. variations = Variations : corrected
15. 4. Model Outcome – updated
16. 5. Tidal Influence– updated
17. Figure 11 is not appropriate. Please, consider that it is not useful to provide identical numbers in table and by column diagramme. Above each of the column the values are given, and the identical values are given in table. You must decide to present this results by graph or in the table. If you select graph with columns, take care on font size and graphical presentations.- replaced by the new table 4
18. 6. Habitat Modelling – corrected
19. rohita – corrected
20. rohita – corrected
21. Chapter References is still not wirtten according the Instructions for Authors.

Check the latest published papers in the journal Hydrology and see how the authors respect the Instructions for Authors.

Journal Names must be abbreviated, not full name.

There is no reason to put signs: ' at the beginning and on the end of the reference title-revised

 

22. Journal name, abbreviated, is missing here Provided : J. Waterw. Port Coast. Ocean Eng.;
23. Journal name, abbreviated, is missing here Clean (Weinh) CLEAN-SOIL AIR WATER
24. Not full name of the journal but abbreviated: River Res Appl
25. Wrong citations. Correct citation is: Beland, K.F., Jordan, R.M., Meister, A.L. Water depth and velocity preferences of spawning Atlantic salmon in Maine Rivers. N. Am. J. Fish. Manag. 1982, 2, 11-13- revised
26. Ecol Appl
27. Zhang, H., Wang, C.Y., Wu, J.M., Du, H., Wei, Q.W., Kang, M. Physical habitat assessment of a remaining high-biodiversity reach of the Upper Yangtze River, China. Appl. Ecol. Environ. Sci. 2016, 14, 129-143- updated

 

Author Response File: Author Response.docx