All reviews of published articles are made public. This includes manuscript files, peer review comments, author rebuttals and revised materials. Note: This was optional for articles submitted before 13 February 2023.
Peer reviewers are encouraged (but not required) to provide their names to the authors when submitting their peer review. If they agree to provide their name, then their personal profile page will reflect a public acknowledgment that they performed a review (even if the article is rejected). If the article is accepted, then reviewers who provided their name will be associated with the article itself.
The authors have addressed the majority of concerns raised in the previous version. Overall, the revised version of the study is deemed satisfactory.
[# PeerJ Staff Note - this decision was reviewed and approved by Xavier Pochon, a PeerJ Section Editor covering this Section #]
The manuscript is much improved and ready for publication although I feel the figures could get polished a bit more and the terms for the treatments are still hard to catch. But these are trivial things and the editors might ask for changes here.
-
-
-
Dear Editor,
While I believe there are still some unclear methodological aspects, I also noticed that the authors have addressed most of the points raised in the previous version. Th result of the study remains the same, which may raise some controversy among readers, as I think there is no strong evidence for their conclusion. But science is this, generating discussion. I am happy with the revised version of the study.
The authors provided clarification in some of the points raised in previous versions.
The conclusions need to be interpreted under the scope of limited number of individuals and tested under very unnatural conditions.
There are two main concerns regarding your manuscript. The first one is that the study exhibits a lack of sufficient methodological details, rendering it unfeasible to comprehensively evaluate the quality and robustness of its results and conclusions. Essential information is absent, such as the number of offspring per dam in each of the four treatments. Inquiries arise regarding the unequal utilization of male species, the distribution of male species among treatments, and the rationale for measuring growth and mass exclusively from day 90 onwards. Verification of the results necessitates additional information.
The second is that the study demonstrated an effect solely in the early phase (see figure 6), which may be attributed to inadequate statistical and biological knowledge. Growth rates are asymptotic rather than infinite and linear, resulting in rapid initial growth followed by a deceleration. Research indicates a slight increase in growth immediately preceding death (see David Reznick articles). Consequently, when growth rates are categorized, early growth rates appear higher than later ones, independent of treatment effects. Analyzing treatment effects exclusively in early life is insufficient.
The limited methodological information and the utilization of box plots to represent early, middle, and late life growth do not permit a valid assessment of the study's findings. Please, Please bear all these considerations in mind for the next version of your work because they are essential for it to be reproducible and to draw valid conclusions.
[# PeerJ Staff Note: This was a resubmission of an earlier manuscript which received an 'open rejection' decision. R1 and R3 reviewed the prior version #]
This version of the manuscript is much tighter than the first version. All of my original criticisms have been addressed, typically within re-written sections of the manuscript. Presentations of statistical tests of data are more convincing, maybe simply because the writing is better.
-
-
-
This study is an important research especially for people using poeciliid fishes in lifehistory assays where individuals are often raised in isolation. The findings that environmental enrichment and visual social contact increases some welfare aspects will be important for future study designs. I only have some minor comments and recomment publication of this manuscript after minor revision:
Abstract: the abreviations of the treatments hamper a quick and easy following of the authors explanations (especially in the figures). I recomment to change to something more intuitive like social-non-social and enriched - non-enriched.
Introduction: Please consider also early works by Parzefall/ PEters and Zeiske as well as newer works by Timo Thünen on Social Deprivation ("Kaspar-Hauser-Syndrome) in poeciliid and cichlid fishes.
Line278: The behavioral description of the deprived fish should be first mentioned in the results before refered to in the discussion
Line 290ff: Please avoid detailed mentioning of statistical tests etc in the discussion. Same at line 321. Please put stats in the results and focus on interpreations in the discussion.
Figures: I feel figure 2 and 3 can be removed as these data seem to be given in figures 4 and 5. Please only provide figures necessary and move all others to supplement. I suggest to only leave figures in the main text that show treatment effects.
-
-
-
The text is clear and well structured. The topic is well discussed. Some key references are missing. The link between results and discussion is difficult to assess given the unclarity of methodological detail.
The study addresses a scientifically relevant topic. However, there are some critical errors and lack of methodological detail that prevent the accurate assessment of the validity of the results. More information and justification is needed.
Please see point above. The methods are vague and key information is missing and in some stages wrong. The main result cannot be scientifically assess.
COMMENTS
Lines 30-31 – “Environment” is a broader concept. In your specific case the two aspects tested were “physical” and “social” components. I suggest a change to reflect the scale of the results and avoid making extrapolations.
Line 30 – I do not want to be picky here, but as mentioned above the study examined two very specific components of the environment.
Line 106 – please see papers by Michael Webster and Christian Rutz (https://www.nature.com/articles/d41586-020-01751-5 and https://onlinelibrary.wiley.com/doi/full/10.1111/eth.13118). I believe these two key papers shouldn’t be omitted.
Lines 109-110 – Social isolation not always produce negative impacts. For example, in poecilids there are no sexual behaviour impacts of social deprivation. This paper should probably be mentioned (https://onlinelibrary.wiley.com/doi/full/10.1111/eth.12087)
Lines 123 and 136 – This is rather confusing. Is meiosis absence of present in this species?
Line 124 – please explain what you mean by “variability documented”? this needs to be more specific
Line 134 – more detail is needed here. How many individuals were housed in the 9 l and on the 40 l tanks? Given that the aims of the study are to tease the effects of physical and social enrichment, it is probably important that the rearing conditions of the mothers are consistent.
Lines 140-141 – more information is needed here. How many of the 9 mothers gave birth? Were the offspring allocated to their treatments by mother linage? Ie. I am confused because if siblings are all allocated to the same experimental treatment, this could bias the result. It is critical that you provide more detail about number of offspring per mother and how these were allocated to each treatment.
Line 30 – Were all offspring maintained in the same tank? Were they separated by Mother ID? Why waiting 30 days to allocated to the treatment?
Line 30 – Further, nn lines 109-110 you mentioned that social isolation has an effect. Were the offspring reared in sociality until reaching 30 days? How were the holding tanks? Ie size, plastic plants, etc? You need to provide more information so the reader can fully understand what was done and if conditions prior to 30 days may have had an effect
Line 160 – from which treatment?
Line 161 – from which treatment?
Line 165 – More information is required here. I do not understand how growth rate was estimated after 90 days (from what I understand the first measure was done on day 90). Also, what is the rationale for measuring length once every month? I suggest Reading David Reznick’s papers of life history traits to better understand how growth rate should be estimated. Given that Poecilids grow faster at the start of their lifes, I am concern that by just starting length measurements at 90 days an important aspect of the variable is missed
Lines 167-171 – Please provide the units of measurement
Lines 173 – 179 – Please provide more information about how the splitting of the P Mexicana and P latipinna was done across the 4 treatments? Why not use a single species? I am concern that the variability in male species may have affected the results
Lines 177-178 – 29 individuals were paired with P Mexicana. And 11 with P latipinna. Were these individuals allocated to which experimental treatments? 29/4 = 7.25, which means that some treatments got more P Mexicana males than others. 11/4 =2.7, again how was this balanced across treatments?
More information about how the split of males was done across treatments. Maybe add a diagram of the sampling design?
Line 189 – (Figure 1) After allowing …. I believe there is a stop missing here
Lines 189-190- why 10 minutes? Can you provide support for this? My understanding is that individuals show signs of settled once they start swimming normally. This can take somewhere between 30 seconds to more than 10 minutes (please see Evolutionary Ecology by Anne Magurran). By having a set 10 minutes you may have started the observation when the individual was not settled.
Line 206 – Chi-square or binomial test? Please provide more detail when one, or the other was used. At the moment this decision seems rather random.
Line 207 – “when appropriate”. Care to expand on this?
Line 208 – please explain what life history measurements were taken? At the moment number of offsprings and growth are the only variables I notice were recorded. Also, how many broods were recorded? At the moment it is not clear if reproduction and growth were estimate across lifetime.
Lines 209 – 210 – Well this needs to be explained. The CLT has assumptions which I don’t think are met here. Further, 20 replicates is not a large sample size. Also, this number is probably smaller when you split individuals by Mother ID and father species. You always need to test the probability distribution to assess in a Gaussian can or not be used in the model. Further, there were only nine fish that produce a brood…
Lines 211- 212 – posthoc tests need to be corrected to avoid Type I error. Please provide evidence that this was done
Line 216 – Repetition “Fish were not measured before day 90 to avoid harm associated with handling”
Lines 219-220 – was Bonferroni correction applied? “Pairwise post hoc comparisons using Tukey HSD tests revealed that EN fish weighed more than”
Lines 224-226 – this is not results and should be moved to methods “We recorded an increase in body size (standard length) (Figure 4) and weight (grams) (Figure 5) over study time. In principle, fish have indeterminate growth, but independent of the treatment, the raw growth slowed down considerably after Day 210.
Lines 245-246 – As mentioned above please justify why using two species of males and not making a balanced design?
Lines 281- 283 – was this recorded? There is no information in the methods
Line 283 – what was the stress response metric used?
Line 261 – I am not sure what this is showing. Was the comparison of mortality rate between treatments? Or within treatments? Also, was the binomial used? If not I suggest removing it from the methods.
Lines 297-299 – this is not mentioned in the results
Figure 9 is misleading. Growth rate is asymptotic. It is faster at the start of life and then slows down. By pooling the data into categories (start, mid, and end) off course the larger box will always be the one at the start. This does not mean that the effect will be greater at the start of the life. A better way to depict an effect would be to have time on the x and growth rate on the y, and plot the raw data for each treatment. Fit lines and look at the slope.
All text and materials provided via this peer-review history page are made available under a Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.