Optimal Method for Biomass Estimation in a Cladoceran Species, Daphnia Magna (Straus, 1820): Evaluating Length–Weight Regression Equations and Deriving Estimation Equations Using Body Length, Width and Lateral Area

Round 1

Reviewer 1 Report

 

Comments of Reviewer: Manuscript ID sustainability-1785744

 

Entitled „Optimal method for biomass estimation in a cladoceran species (Daphnia magna): evaluating length-weight regression equations and deriving estimation equations using body length, width and lateral area”

 

General comments: The manuscript is well written, gives us a new approach for the biomass calculation in laboratorial conditions in case of Daphnia species. The introduction part covers the most significant existing literature of biomass estimations and general knowledge of Cladocera species. The used specimens are a very well accepted model organism over the world, and the used statistical methods are appropriate for the estimations. The results are clear and concise. The discussion section can be detailed more, with some comparison with other results. In this form only states the authors findings without giving explanations. The manuscript English is good, but a few sentences are too long and (very) complex, which can sometimes be confusing and hardly interpretable.

 

Minor comments:

The overall length of the introduction is acceptable, but I would like to see some more information about why the biomass is important (not just repeating the importance of food web and energy flow).

line 74: (visually dependent predators) be a little more specific, not just the visibility the only factor, there are a lot of planktivorous fish species which are not depending on the visibility when feeding

line 95 and title: when species name mentioned first, please indicate the descriptor and year too

Section 2.1.: there are no information on the repetitions number and for how many days they cultured the Daphnia species, and the volume of the aquarium (or tank) used for the culturing. Also lack of information about the volume of food (Chlorella sp.) added per day. Please indicate these.

line 201-203: its not a result, it needs to go to the discussion section.

 

Major comments:

Aims/hypothesis: for me it seems that the authors not aimed or hypothesized anything. They got the data and based on; they wrote down what they did. It will be a little luckier if they write down their previously aimed targets. It gives us a more predictable finding. E.g.: aimed on to evaluate the suitability…. we hypothesized that our regression equation will be more suitable for biomass estimation, etc… please refine and specify your aims.

 

Discussion: as it stands, this section lack on explanations. The authors got useful data during the experiment, but the interpretations of it is scarce. Please include more available data (previously published data), what other find, those are higher/lower, better/worser than your data, etc… In this form with the lack of aim/hypothesis, just a freer explanation of the authors finding. Please put in more information, comparison and with that the authors discussion/conclusions stands way way harder.

Author Response

Dear Reviewer,

Thank you for your valuable opinion on our research paper. Please refer to the attached file for our detailed responses to your comments.

Best regards,

Author Response File: Author Response.pdf

Reviewer 2 Report

Review

Paper title: Optimal method for biomass estimation in a cladoceran species (Daphnia magna): evaluating length–weight regression equations and deriving estimation equations using body length, width and lateral area

 

The authors measured the biomass of the common cladoceran Daphnia magna through a direct method (weighing using a microbalance). They compared the results with the data obtained from standard length-weight regression equations and found significant differences between the actual and calculated data. The authors concluded that actual biomass values in Daphnia can be underestimated. The authors suggested that body length is a more appropriate parameter for size-weight relationships than body width and body area and that a linear regression equation provides the best data fit when compared to logarithmic and exponential functions. These results are important for a more accurate measurement of zooplankton biomass in freshwater ecosystems.

 

All these reasons explain the relevance of the paper by Doyeong Ku and co-authors submitted to "Sustainability".

 

General scores.

 

The data presented by the authors are original and significant. The study is correctly designed and the authors used appropriate sampling methods. In general, statistical analyses are performed with good technical standards. The authors conducted careful work that may attract the attention of a wide range of specialists focused on plankton ecology.

 

Major concern.

The authors used a parametric test (one-way ANOVA). This approach requires normal distribution and heterogeneity of the data. The authors should provide the methods used to test these assumptions. The authors should also clarify the method used for post hoc comparisons between pairs of biomass values and mention it in L. 174.

 

Specific comments.

L 150. Change “from model fitting” to “from the model fitting”

L 151. Change “value” to “values”

L 173. Change “among” to “between”

L 187. Change “regression  analysis” to “the regression  analysis”

Author Response

Dear Reviewer,

Thank you for your valuable opinion on our research paper. Please refer to the attached file for our detailed responses to your comments.

Best regards,

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

 

In this present form, with all of the suggested modification, I'll accept all of your answers.