Spatial and Temporal Variability of Parasite Communities: Implications for Fish Stock Identification
Round 1
Reviewer 1 Report
This Ms look on the use of parasites as biological tags for fish stock identification. Particularly focusing in spatial and temporal variability in composition and abundance of the parasites as a key issue of parasites as biological tags for fish stock identification. It is a well disigned study, the analyses are correct and well done. The results are original and important. This Ms deserves publication.
However, I would strongly encourage the authors to restructure the discusion section. The results are not sufficiently interrogated in the discusion. We suggest shortening the section by cutting the generalities. Instead, highligth the principal findings of this research. It is a must for the discussion.
I would suggest also the next to the authors:
To objectively determine the helminth taxa most responsible for grouping. For example by using SIMPER analysis of the data by each host. This approach cn be used to determine the parasite taxa that contribute to differences between communities.
ANOSIM analysis can confound the differences between groups and dispersion between groups, therefore the results can be difficult to interpret. Most R values presented in this Ms suggest that dissimilarities are greater within groups than between groups. However, ANOSIM is very sensitive to heterogeneity and dispersion. In contrast PERMANOVA is largely unaffected by heterogeneity. It would be useful for a strongest conclusion to evaluate simultaneously both the differences in location and spread by applying PERMANOVA analysis. The idea of PERMANOVA is to determine the possible differences in the location (means) and spread (dispersion) of the parasite taxa from the compared groups. When getting a PERMANOVA statistically significant output, then one is lead to believe that there are differences between groups. These differences can be because the community composition of parasite taxa in groups are distinct.
Finnally, add a legend for each excel table in supplementary material. And present these tables with a more definitive format.
Comments for author File: 
Comments.pdf
Author Response
To objectively determine the helminth taxa most responsible for grouping. For example by using SIMPER analysis of the data by each host. This approach cn be used to determine the parasite taxa that contribute to differences between communities.
Response: The referee is right when indicate the need for the objective identification of parasite taxa (not only helminth) in studies regarding stock identification using parasites as biological tags. Our goal is not to evaluate the stock structure of the studied fish species, (done early), but evaluate the potential spatial and temporal variability of parasite communities as confounding factor in stock identification.
ANOSIM analysis can confound the differences between groups and dispersion between groups, therefore the results can be difficult to interpret. Most R values presented in this Ms suggest that dissimilarities are greater within groups than between groups. However, ANOSIM is very sensitive to heterogeneity and dispersion. In contrast PERMANOVA is largely unaffected by heterogeneity. It would be useful for a strongest conclusion to evaluate simultaneously both the differences in location and spread by applying PERMANOVA analysis. The idea of PERMANOVA is to determine the possible differences in the location (means) and spread (dispersion) of the parasite taxa from the compared groups. When getting a PERMANOVA statistically significant output, then one is lead to believe that there are differences between groups. These differences can be because the community composition of parasite taxa in groups are distinct.
R: Following reviewer suggestion, PERMANOVA was included as a statistical tool. Result do not change
Aadd a legend for each excel table in supplementary material. And present these tables with a more definitive format.
R: Done. A paragraph was included
Reviewer 2 Report
General comments
The study "Fishes - 1450080" presents data on the impact of spatial and temporal variability when metazoan parasite communities are used as a tool for stock identification. I believe the study will be of interest to “Fishes” readers, but first I recommend carrying out a minor revision of the manuscript.
Introduction: The introduction is well written and presents the main theme of the article. In addition, it is possible to observe the mention of previous studies and the objectives of the study conducted.
Materials and methods: I don't understand how was estimated fish age. How was the age group assigned? By otoliths? Please specify
Discussion Line 244-245: More references should be provided … “studies have used the length of fishes to compare groups of fishes from different localities
for instance:
P.E. Braicovich* and J.T. Timi Parasites as biological tags for stock discrimination of the Brazilian flathead Percophis brasiliensis in the south-west Atlantic (2008) Journal of Fish Biology 73, 557–571
Bottari T., Gaglio G., Mobilia V., Garofalo G., Iaria C., Fiorentino F. 2020. Discrimination of red mullet populations (Teleostean, Mullidae) off the Sicilian coasts (Mediterranean Sea) on the basis of metazoan parasites. Thalassas: An International Journal of Marine Sciences
References
Line 421: Froese and Pauly, 2021
Figures: The supplied images are of limited resolution.
Author Response
Materials and methods: I don't understand how was estimated fish age. How was the age group assigned? By otoliths? Please specify
R: In Material and Methods section (lines 102-105 original submission), the parameters for the von Bertalanffy growth function (L∞ To and K) are given as well as the corresponding reference. The von bertalanffy growth function allows us to estimate the age at the size provided we known the parameters already indicated.
Discussion Line 244-245: More references should be provided … “studies have used the length of fishes to compare groups of fishes from different localities
R: Done. New references were included
