Production of Marine Shrimp Integrated with Tilapia at High Densities and in a Biofloc System: Choosing the Best Spatial Configuration
, Wilson Wasielesky, Jr. 1, Gabriele Rodrigues de Lara 2,* and Luís H. Poersch 1Round 1
Reviewer 1 Report
This paper entitled “Production of marine shrimp integrated with tilapia at high densities and in a biofloc system: choosing the best spatial configuration” describes the effectiveness of the integrated multitrophic aquaculture (IMTA) system and shows the high growth performance of shrimp and fish cultured in different tanks.
Aquaculture together with multitrophic animals itself is not a novel technique. However, the authors demonstrated that IMTA in different tanks gave significantly higher yields than that in the same tank. This point is very important for sustainable aquacultures in high animal density using a recirculation system.
However, there are some points to be revised in the text. The authors are requested to revise MS carefully according to the reviewer’s comments before accepting and publishing the manuscript.
In general
Although “biofloc” was emphasized in the Title and Introduction, very few descriptions on biofloc were in the text. The authors should explain; 1) how different biofloc and TSS, 2) how biofloc was prepared in the experiment, 3) what characteristics it had, and 4) how biofloc functioned in IMTA, if they want to emphasize it.
Specific comments
1. Introduction, line 28
Please give the definition of “biofloc” and “biofloc system”. At least, brief descriptions on them should be added to the Introduction.
2. Introduction, l. 42
Please give more explanation on “clarifiers”. Is it a precipitation tank?
3. Introduction, l. 56
What is BFT? Please give the full text when abbreviations are present at first. Is it “biofloc technique”?
4. M & M, l. 87
How long shrimp juveniles were acclimated? Same as tilapia (two weeks)?
5. M & M, l. 97
How did you prepare “mature biofloc”? What does “20% of the volume of the experimental tank” mean? Total volume of biofloc was 44 L (220L x 0.2)?
6. Tables 1 and 2
Reliability of parameters measured will be usually the 3 decimal places except for some parameters (such as salinity). Please correct all the figure expression.
For example, TSS 293.67 should be 294.
7. Table 1
Concentrations of NO3-N were around 31-32 mg L-1, which corresponds to about 2.2 mM. In spite of such very high concentrations of nitrate, pH values were not acid (around 7.9). Is it due to the high alkalinity? Please add some description on this point.
8. Table 2
Total final biomass of IMTA DT is 646.8. Is it correct? It should be 627.1, a reviewer supposes. Please check all the values in Tables once again.
9. Discussion, l. 271
[to increase the biomass produced in the IMTA DT treatment by 211%].
A reviewer cannot understand how 211% was obtained. Please show how did you calculate and obtain this value.
Author Response
September 29th of 2022
Dear Editorial Board of Fishes and Reviewers,
We appreciate you taking the time to consider our work. We addressed the queries made by the referees below and the changes are highlighted in yellow in the manuscript.
Reviewer: 1
This paper entitled “Production of marine shrimp integrated with tilapia at high densities and in a biofloc system: choosing the best spatial configuration” describes the effectiveness of the integrated multitrophic aquaculture (IMTA) system and shows the high growth performance of shrimp and fish cultured in different tanks.
Aquaculture together with multitrophic animals itself is not a novel technique. However, the authors demonstrated that IMTA in different tanks gave significantly higher yields than that in the same tank. This point is very important for sustainable aquacultures in high animal density using a recirculation system.
However, there are some points to be revised in the text. The authors are requested to revise MS carefully according to the reviewer’s comments before accepting and publishing the manuscript.
Response: We appreciate the considerations.
In general
Although “biofloc” was emphasized in the Title and Introduction, very few descriptions on biofloc were in the text. The authors should explain; 1) how different biofloc and TSS, 2) how biofloc was prepared in the experiment, 3) what characteristics it had, and 4) how biofloc functioned in IMTA, if they want to emphasize it.
Response:
- There is no difference, we just use the term TSS to refer to the analysis performed. To remove the doubt between the use of the terms, we add a short reference in line 41, after the first reference to TSS.
- We have modified part of the methodology to make it clearer: [20]. The inoculum was taken from a 60 day culture of vannamei with a density of 400/m³ in 35 m³ tanks from a L. vannamei cultivation in a greenhouse, molasses with a carbon source was used in initial phases of cultivation for ammonia control, with initial concentration ±350 mg L−1 of TSS and ±70 mg L-1 of nitrate, indicating that the nitrification process was taking place in this matrix tank.
- same comment as in item 2
Specific comments
- Introduction, line 28: Please give the definition of “biofloc” and “biofloc system”. At least, brief descriptions on them should be added to the Introduction.
Response: Changed in the text: Biofloc technology (or biofloc system or BFT system - Biofloc Technology system) is characterized by super intensive production of aquatic organisms, minimal or no water renewal and cycling of the nutrients in the tank itself by the stimulation of a microbiota that forms microbial aggregates [2]. Besides maintaining water quality in the system, as the ammonia is removed by heterotrophic bacteria [3], these aggregates also serve as food for the reared animals [4]. The removal of toxic nitrogen compounds in the biofloc system is the key to the success of this technology in aquaculture.
- Introduction, l. 42: Please give more explanation on “clarifiers”. Is it a precipitation tank?
Response: Changed in the text: For this purpose, mechanical clarifiers, which function as particle decanters for the removal of particulate organic matter by gravitational action in a slow radial water flow, are generally used [7].
- Introduction, l. 56: What is BFT? Please give the full text when abbreviations are present at first. Is it “biofloc technique”?
Response: We removed the abbreviations and standardized the expression bioflocc throughout the text
- M & M, l. 87: How long shrimp juveniles were acclimated? Same as tilapia (two weeks)?
Response: modified in manuscript: Shrimp juveniles of L. vannamei were obtained from a commercial hatchery and they were acclimated in a biofloc system for two weeks.
- M & M, l. 97: How did you prepare “mature biofloc”? What does “20% of the volume of the experimental tank” mean? Total volume of biofloc was 44 L (220L x 0.2)?
Response: modified in manuscript: A biofloc inoculum was used in the experimental units were stocked with mature bioflocs, corresponding to 20% of the volume of the experimental tank (44 L of inoculum + 176 L of sea water), according Krummenauer et al., [20]. The inoculum was taken from a 60-day culture of L. vannamei with a density of 400/m³ in 35 m³ tanks from a L. vannamei cultivation in a greenhouse, molasses with a carbon source was used in initial phases of cultivation for ammonia control, with initial concentration ±350 mg L−1 of TSS and ±70 mg L-1 of nitrate, indicating that the nitrification process was taking place in this matrix tank.
- Tables 1 and 2: Reliability of parameters measured will be usually the 3 decimal places except for some parameters (such as salinity). Please correct all the figure expression.
For example, TSS 293.67 should be 294.
Response: modified in manuscript
- Table 1: Concentrations of NO3-N were around 31-32 mg L-1, which corresponds to about 2.2 mM. In spite of such very high concentrations of nitrate, pH values were not acid (around 7.9). Is it due to the high alkalinity? Please add some description on this point.
Response: Added to the text: Despite the high nitrate values at the end of the experimental period, the pH values were above 7.9, without acidification of the medium because of the successive pH and alkalinity corrections during the experiment as described by Furtado et al., [25].
- Table 2: Total final biomass of IMTA DT is 646.8. Is it correct? It should be 627.1, a reviewer supposes. Please check all the values in Tables once again.
Response: We checked the results and made the modification suggested by the reviewer.
- Discussion, l. 271: [to increase the biomass produced in the IMTA DT treatment by 211%]. A reviewer cannot understand how 211% was obtained. Please show how did you calculate and obtain this value
Response: We check the results and change the value. If we compare the total biomass produced in the IMTA DT treatment to the Monoculture treatment, the gain in final biomass was 175%.
Reviewer 2 Report
This is a straightforward and robust study. I have made some minor changes on the annotated pdf. The abstract could do with a little more attention.
Comments for author File: 
Comments.pdf
Author Response
September 29th of 2022
Dear Editorial Board of Fishes and Reviewers,
We appreciate you taking the time to consider our work. We addressed the queries made by the referees below and the changes are highlighted in yellow in the manuscript.
Reviewer: 2
Line 12: A viable alternative to what?
Response: modified in manuscript: Integrating marine shrimp and tilapia has been shown to be a viable alternative in a system based on bioflocs, but there is no consensus on the spatial arrangement of farmed animals.
Line 19: Put the species names with the common names
Response: modified in manuscript
Line 56: What is the full term for this abbreviation?
Response: We have removed abbreviations and standardized the use of the term biofloc throughout the text.
Line 102: Can a reference be provided for this method? Why is it being neutralized? – more explanation needed please.
Response: A blend of sea water (previously chlorinated and neutralized with ascorbic acid, according Roselet et al., [21]).
Line 128: Were these animals returned to the tanks or were they sacrificed?
Response: To perform the biometrics, the tilapias were anesthetized with 50 mg L-1 benzocaine hydrochloride in aqueous solution, and after complete recovery, were returned to the experimental units
Line 203-204: a space or a hyphen is needed here
Response: modified in manuscript
Round 2
Reviewer 1 Report
Please see the attached file.
Comments for author File: Comments.pdf
Author Response
We appreciate you taking the time to consider our work. We addressed the queries made by the referees below and the changes are highlighted in green in the manuscript.
best regards
Luis Poersch
Author Response File: Author Response.pdf
