Geographic Variation in Opisthonema oglinum (Lesueur, 1818) in the Southeastern Brazilian Bight Inferred from Otolith Shape and Chemical Signatures
, Kathleen Angélica Rautenberg 1, Cristiane Gallego Augusto 2, Eduardo Luis Cupertino Ballester 3, Paulo Ricardo Schwingel 4, Edgar Pinto 5, Agostinho Almeida 6 and Alberto Teodorico Correia 7,8,9,*
Round 1
Reviewer 1 Report
Dear Authors,
I found this manuscript well-written and organized, with an important amount of analyses and some essential key results for the topic. Well done!
Despite the sample collection being rather old, and some ecological relapses could be weak, I've appreciated your results exposition and discussions, but please highlight this limitation linking to the last part of the discussion section in a more clear form.
Please add the reference to the species' scientific name in the title and first-time mention in the abstract section, (Lesuer, 1818).
Lines 294-306: this is an essential part of the discussion section, in my opinion, related to very important ecological relapses of otolith sciences applications. Please better argue and compare your results on shape analysis with some other references from upwelling areas to enhance the soundness of these particular zones and their influences on otolith’s variability which is still largely unknown. See for example:
10.1371/journal.pone.0281621
No mention of the study of lagenar and utricular otoliths was done within the entire manuscript. Considering the importance that these other tools are acquiring in the last years, even more comparable with the saccular one, both in introduction and in the last part of the discussion section (as a limitation) should mentioned something about this topic. Even if the sample collection has not foreseen at the time the collection of these samples, should still be justified to correctly frame your good study, also to better argue the conclusion section. See for example:
10.1071/MF12132
10.1046/j.1095-8649.2003.00106
10.3989/scimar.2005.69n2259
Best regards
The Reviewer
Author Response
Please see the rebuttal letter (Reviewer 1)
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear authors. Your paper represent a good peace of work for analysis of stock structure of small pelagic commercially important fish species.
Here is my line-by-line reocommendations.
Line 91. You say about behavior. What do you mean? Please specify or rephrase the sentence.
Line 94. It is not clear what pattern you talking about. Increasing the landings of clupeids in comparison of scombrids?
Line 109. You say “The current scenario demands”. Is that mean “ The aim of this study”? Please rephrase if so.
Line 111-112. What was the basement of your hypothesis? Please put some references.
Line 118-136. At the study area section please specify the difference on environmental characteristics between two cites. There is some information on RJ but not about SC cite.
Line 136. Did you mean “the most productive” ?
Line 148 -150. You used fish of the same size for the analysis and also analyzed the age. Is it correct? If so, why you did not compare the growth of the fish from two fishing areas you studied? Later in the discussion you say that Santa Catarina inshore waters are less productive area (Line 298). That mean that fish from this area can be older than fish from Rio de Janeiro. That can be the biological marker for the stocks you studied. Please compare the fish growth and include this data to the paper.
Line 220. Please cut the repetition of the word “transformed”.
Line 284-291. The figure and the table are showing the same information. I suggest to cut table 1 and include results of t-test showing significant difference on the graphs on Fig 5. Otherwise, you can cut figure 5 without any loss of information.
Line 353-354. You say: “Current results did not follow the expected pattern in relation to the temperature”. Did you statistically check the effect of temperature at sampling cites on Mg/Ca? If so, please insert the following information to the “Materials and Methods” section. Also, you mentioned that Santa Catarina cite is less productive. Following this logic, fish consume less food there what should result in low Mg/Ca. But your results showing opposite pattern. Please rework the paragraph (Line 352-361) to exclude this contradiction.
Author Response
See rebuttal letter (Reviewer 2)
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors completed correction of the manuscript which can be published.
