Characteristics of the Stone Crayfish Population along a Disturbance Gradient—A Case Study of the Kustošak Stream, Croatia

Round 1

Reviewer 1 Report

no comment

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In the manuscript entitled "Characteristics of the stone crayfish population along a disturbance gradient – a case study of the Kustošak Stream, Croatia" by Tarandek et al., the water quality and stone crayfish population structure from three sites were compared to assess how habitat alteration affect crayfish population. The authors conclude that habitat alteration caused reduction in population abundance and structure, however, did not yet result in detectable genetic differences.

The work done is worthful that will be of interest to the readers of the journal. As a reviewer, I feel that, though commendable work has been done, there are many detail errors in the manuscript. I have pointed out only some of the errors that I came across. Accordingly, in my opinion it could be accepted after minor corrections.

 

Some of the major drawbacks of the manuscript are as follows:

*The distance of the three sampling sites is too close. In my perception, most crayfish such as Procambarus clarkii have strong swimming ability and can migrate for a long distance within a few days, especially in flowing water. This may be the reason that there is no detectable genetic differences among the three sites.

*Is there the special crayfish catching tools, such as crayfish ground cage? The stone crayfish capture amount in the three sites was insufficient, especially for the sites 2 and 3. Or each site should have at least three replicates (> 30 individuals for each repeat).

*Can the oil-based marker pen be used to mark stone crayfish? In my experience, the oil-based pen markers at the exoskeleton are easily worn out.

*there are more bigger crayfish in sites 2 and 3 than that of site1, which may be attributed to that the big crayfish can move more far distance, but the small one can not?

*I suggest the author provide the photograph of stone crayfish in the revised manuscript.

 

Specific comments:

*Line 186, Line 267, Line 286, Line 351: ‘P’ should be italic.

*Line 226-227, Line 338, Line 347: ‘HO’, ‘HE’ should be italic.

*Line 356: ‘ΔK’ K should be italic.

*Line 491: ‘COI’ gene name should be italic.

 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The authors study a key species (the stone crayfish) in freshwater habitats which is under protection in many European countries and present new information on its population structure and genetic diversity. The study although of local importance is still necessary for the conservation and management of the species in the area and especially since part of the study is taking place in a national park. Furthermore, new information such as new haplotypes and new microsatelite markers are produced that complements previous studies on the species in Croatia and in turn aid further its conservation. For the above reasons I recommend this paper to be published but before doing this I have to raise my concern regarding the sampling that only took place once. 

The study is based on a one-time collection (in a span of a week) of crayfish specimen, which I find barely sufficient for a population study. A repeated sampling throughout a year (ideally monthly or seasonal) will have had significant outcome concerning the crayfish characteristics and the population parameters. The repeated sampling will have showcase whether there is a strong relationship between these parameters and habitat degradation, while a more holistic picture of the population in the specific habitat will have formed. Although most likely the authors are correct on their explanation that habitat degradation is responsible for the reduced numbers of individuals and the absence of age classes as well as a reduced genetic diversity this is not strongly supported based on the sampling design, but rather the results are over-explained. The authors should keep this in mind when discussing their results and be more restrained in their explanations. 

Finally, I am including a pdf with some corrections on the text as well as some comments to be addressed. 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I think it can be accepted now.