Can the Life History Trait Divergence of Two Extremes of a Cold-Water Genus Distribution Offer Evidence for Their Vulnerability to Sea Warming?

Round 1

Reviewer 1 Report

 

The manuscript titled “Can life history traits divergences between the extremes of a 2 cold-water genus distribution tell us something about their vulnerability to sea warming?” contributes to improve the knowledge gap on aspects of Molva species biology, essential for the application of robust conservation measures.

The authors took care of the reproductive aspects very well with particular attention to the histological analysis, especially for M. macrophthalma in which the study is based on an annual sampling. The weak aspect of this study concerns the few samples of M. dypterygia, only two months of sampling, which makes the comparison between the two species difficult.

More detailed information on the reproductive period of M. dypterygia should have representative samples of the four seasons, consequently in this study the authors should revise the sampling plan to return more robust and comparable results between the two species.

The analyses carried out have the correct setting but for the aspect linked to sampling of M. dypterygia, the manuscript needs major revisions for publication in this journal.

Other comments are within the text.

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Reviewer 2 Report

The manuscript is generally well written except that is seems a little lengthy (especially result and discussion sections). I wonder if the author can cut down their Results and Discussion Sections a little bit. The full name of DV, SC et al should also be provide in Table 1. Furthermore, why did the authors not provide the statistical results of the difference between two cites (which is the main finding of this study) in Table 1 (and other figures and tables as well). There were only 89 and 81 species in two cites,and the sample can only collected in November and March for one fish species. I do understand that it is difficult to get enough samples, however, i suggest the authors discuss a little bit in discussion section whether it might has some effect on the results of the study.

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Reviewer 3 Report

The manuscript showed the different strategy of Molva species lives in Mediterranean Sea and Icelandic Ocean. The data was processed correctly, and the results are important in regard to the research on the climate changes, especially the change of marine temperature, on the vitellogenesis of fish. The research is suitable to be published on Fishes. There is one question on the research before the MS can be accepted.

 

The research focused on the comparison of two Molva species, M. macrophthalma and M. dypterygia. The parameters measured, for instance, body condition and reproductive cycle, were different in the comparison. However, this difference could be because they are different species, other than the difference of water temperature. For example, there are difference in the breeding strategy between horse (Equus caballus) and dunkey (Equus asinus). Could the authors explain the reason using two species in the research other than using one species living in different zone, like gilthead sea bream which is distributed from British Isles to Canary Island?

Author Response

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Round 2

Reviewer 1 Report

The authors have answered in an exhaustive way to the perplexities presented by me, especially explaining that the main subject of this paper is the population of M. macrophthalma presented in depth with congruous results and well discussed. Moreover, they also highlighted that the two seasons of sampling selected for M. dypterygia represent two phases relevant in terms of reproduction: autumn, when gonads are supposed to be developing; and late-winter and beginning of spring, when specimens are expected to be ready to spawn. This is a strong point in weak sampling for M. dypterygia.

The authors made the right corrections within the text, consequently my opinion is that the manuscript can be accepted for the publication.