Endurance Swimming Is Related to Summer Lake Survival of Rainbow Trout in a Warm Lake with Avian Piscivores
Round 1
Reviewer 1 Report
The manuscript: "Endurance Swimming is Related to Summer Lake Survival of Rainbow Trout in Warm High Predation Lakes: A Comparison of Diploid and Triploid Swimming Endurance and Survival in the Wild" is interesting and well written. I have only minor comments.
Minor comments:
L: 32 - Delete repetition of "in a warm"
L: 68 - Scientific name "Poecilia reticulata" should be written in italic
L: 147 - Delete a bracket
L: 227 - Delete repetition of "cf"
L: 247 - Delete brackets
Please, discuss possible interaction of trouts with other organisms as signal crayfish and cite positions as below:
Peay et al. 2009. The impact of signal crayfish (Pacifastacus leniusculus) on the recruitment of salmonid fish in a headwater stream in Yorkshire, England. KMAE 394-395, 12.
Dobrzycka-Krahel et al. 2017. Signal crayfish Pacifastacus leniusculus – distribution and invasion in the southern Baltic coastal river. Polish Journal of Ecology 65 (3): 444-450.
Author Response
Please see attached file for responses.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
General comments
This study assesses the link between locomotion performance and fitness in rainbow trout. More specifically, differences in survival were related with locomotion performance by stocking two experimental lakes during summer high temperatures with sibling diploid and triploid rainbow trout populations of genetically identical origin, given the lower triploid fish aerobic swimming performance. Individual fish were tested for endurance prior to stocking and marked for their endurance quantile, being stocked into the two lakes as yearlings to assess survival as a function of ploidy, temperature, and endurance. Moreover, temperature and depth habitat utilization were tracked for a few diploid and triploid specimens. Aerobic swimming endurance, particularly for 3N, was related with the summer survival of trout in the lake with higher predation pressure from piscivorous birds.
The study is interesting and is likely to be of interest to readers of Fishes. Although aspects of the experimental design could be subjected to some criticism, namely the lack of a more robust assessment of the differential predation pressure in the two experimental lakes, and the fact that given the distinct morphometry of the two lakes it is not possible to disentangle the effects of morphometry (and the higher temperature in the lake with higher trout mortality) from the ones influenced by the variable predation pressure. Nevertheless, recognizing the effort made and the interest of the material reported I believe the study is solid enough to merit eventual publication.
Below are some specific comments that should be addressed by the authors.
Specific comments
Lines 301-303. Please complete the Figure 2 caption. The temperature color scale is missing, as is the O2 scale.
Lines 411-416. Table 2 - Please add more details for the analysis performed other than the significance levels.
Lines 423-429. Do not repeat in the text the values that are presented in Table 3. Please review all the text with the aim of reducing the overall ms. length.
Lines 434-435. “The best-fit generalized liner model testing for a significant effect of endurance quartile on fish survival in 2008 included a three-way interaction among ploidy, endurance, and lake (p=0.047) (Table 2)”. The analysis p value is not concordant with the one presented in Table 2 (p<0.001). Please also note that you refer to use a significance cutoff of p<0.01.
Author Response
Please see attached file for responses.
Author Response File: Author Response.pdf
Reviewer 3 Report
I have read through the manuscript entitled as 'Endurance Swimming is Related to Summer Lake Survival of Rainbow Trout in Warm High Predation Lakes: A Comparison of Diploid and Triploid Swimming Endurance and Survival in the Wild'. The authors conducted a nice and comprehensive study. The conclusion is solid, and the manuscript is well written. I think the manuscript is ready to publish on the present version. The only concern is the length of the paper. I wonder if it possible for the author to shorten the discussion section and introduction section (e.g. combine the third and fourth paragraph of introduction section) a little bit.
Author Response
Please see attached file for responses.
Author Response File: Author Response.pdf
Reviewer 4 Report
MS : ID fishes-2285880
Title : Endurance swimming is related to summer lake survival of rainbow trout in warm high predation lakes: a comparison of diploid and triploid swimming endurance and survival in the wild.
Verhille, Farrell.
In this paper project, the authors tried to establish a link between swimming endurance of the rainbow trout and survival under wild conditions (in lakes). If it is a new approach mixing laboratory data (on the swimming endurance) and wild information (on habitat use and survival of fish), this manuscript suffers of a lot of problems to be considered for publication in fishes. There are difficulties on the form to make the text easier to read and to understand, and also fundamental problems.
First on the form:
- In the introduction remove the paragraph on the economic data (lines 86-94) that do not bring any interesting information for your porpose
- In the material and methods, please precise how do you realize capture and recapture?
- The main problem is in the “results” chapter (pages 7 to 12).
I suggest dividing this paragraph into two different parts:
- First all data that concern with the characteristics of the lakes (O2, temperature) should be used to describe the physical environment and could be inserted as “supplementary data” (with tables and figures 2 and 3).
- Second all the data that are related to the habitat use by the fishes during the warmest months of the year (figures 4, 5 and 6) should be maintained in the chapter Results (You can illustrate the data with one figure or two figures - 4 or 5 and 6- and put the other as supplementary data).
Second, I have two problems with your work: one with the concept of “survival” and the second one with that of “swimming endurance”.
- For the first, for you, what are the origins of fish mortality? Is it the predation by birds and/or the warm temperatures during summer? If you can discuss this last point in relation to the lake temperatures, fish tolerance and habitat use, it seems to me more difficult to introduce the level of predation. You did not give any data on these levels in the two lakes just by listing the potential predators and also I have a question: is there other fish species in the lakes and if it is the case how do they support the avian predation? This situation could influence the level of predation on your introduced brown trout.
- The second point is linked to the previous one. Swimming endurance is related to temperature and so to habitat use. Is there competition between 2N and 3N for this habitat use? In this case, 3N could be stocked in the upper part of the lakes near the surface where there is more food (as you suggest) but also where the risks of predation were higher. So, I think that you have to separate the swimming endurance in two different groups as you did lines 45 – 46 in the introduction. If swimming endurance based on prolonged speeds is important to survive, and burst speeds are essential to avoid predators; but in your work, you forgot this last one and we had no information of the differences between the two strains.
So I suggest to focalize your work on the relationships between fish characteristics (survival and swimming endurance) and the physical environmental features (temperature, O2), and to forget the influence of predation because you have no argument for it.
Other comments:
Reduce the title: “Swimming endurance and survival of brown trout are linked to environmental characteristics in lakes”.
We have no information on the social life of your fishes: do they live in shoal of solitary?
L40: remove “specific”
L51: how do you define “swimming performance” relatively to burst or prolonged speeds?
Figure 1: give “failures” in percentage.
Table 1 put it in a supplementary data and remove Predators.
Did you get authorization from a national ethical committee to realize surgery on fish?
In your statistical model, did you use Akikae information criteria (AIC) to select the best model? Moreover in your results, pay attention to the fact that when interaction between variables is significant, you can’t interpret the effect of the variable alone.
In all the result chapters, don’t begin your sentence by “the best fit general model….”, but give directly the results (make tables with all the results of the models not only with the two significant models as in table 2).
How did you obtain the “recapture rate”?
Author Response
Please see attached file for responses.
Author Response File: Author Response.pdf
Round 2
Reviewer 4 Report
The authors made some important corrections to their manuscript and answered to my main comments.
I would have liked some data on the different predation rates in the different lakes (even if they were got from other studies) to maintain the predation as a solid hypothesis for fish survival.
