The Effect of Husbandry and Original Location on the Fouling of Transplanted Panels

Round 1

Reviewer 1 Report

Review of paper

The effect of husbandry and original location on the fouling of transplanted panels

The study is well conducted and nicely documented. The results presented in an illustrative way with thorough statistics. The figures are explanatory and color coding makes it easy to follow. The scope of the paper, investigating hull husbandry for outcome of biofouling after transplant is novel and useful. The transplant is conducted between two sites where I guess there is commercial traffic and salinity vary between the sites. To add a paragraph on the general validity of the results and or limitations would improve the manuscript.

The division into macrofouling and microfouling is logic and could perhaps be included already in the hypothesis 1 and 2 (as is later discussed divided into these groups)

Please find my comments/ questions below:

1)    The hydroids were treated separately, but I did not get if they were removed from the macrofouling dataset (or included in this) I think that should be added for clarification 

2)    I miss some more information about the surfaces, Intersleek are commercial silicone paints, what is DC3140?

3)    I also think some background or rationale for choosing these coatings should be included. Are they commonly used in the area? Is there any previous data on how to perform cleaning on them?

4)    The salinity did differ between the sites but not the temperature. Are the salinity differences expected to have impact on the species abundant at the different sites?

5)    In hypothesis 4 I wonder what “recolonize similarly” mean (same fouling cover? same groups of organisms?) and what was the general outcome/ finding regarding this in the study?

6)    Considering the “NIS-introduction framing”, in regard to what the results from this study means for the issue of NIS-introduction, I think it is somewhat difficult to follow completely. In this study there was no identification to species level so I understand the reasoning has to be more general. NIS are found within all groups investigated in this study (perhaps also in the microfouling?). I think however one great asset with grooming (that can be included) is that with grooming the species are not allowed to grow into the adult and reproductive stages and thereby the possible introduction risk of NIS would decrease.

Author Response

Thank you for the review. Your comments were insightful. I will respond specifically below:

1) I clarified that macrofouling cover is the total macrofouling cover in the methods (lines 168-170) and that the specific taxa are presented separately. I also emphasized that it is total macrofouling cover in Figure captions for 6-8.

2&3) I added a paragraph giving a fuller description of the coatings, and justification for their use in section 2.2.

4) Environmental data was included to characterize the sites. It is possible that some species would be impacted by the difference between the stable and variable salinity at the two sites, as you note, we did not identify taxa to species. 

5) I clarified this by specifying that it was in terms of cover and composition (line 129).

6) Thank you for this comment. I tried to emphasize this in the last paragraph of the discussion. I have added an additional conclusion to more directly state that we believe one of the best ways to limit the transportation of NIS is by continuing to groom to maintain clean hulls.

Reviewer 2 Report

The manuscript introduced an interesting issue regarding the possible management strategies to limit biofouling on boat hulls. This is an aspect poorly investigated and of a crucial importance for limiting the introduction of alien species. In my opinion the manuscript in well written and the results obtained very interesting and useful for the management of the biofouling vector of alien species introduction. On the other hand is very confused the transplant experiment carried out. I would suggest to better explain the role of transplantation in this study and the reason of performing such manipulation to assess hull husbandry, because without considering the transplantation of panels you collected interesting data. Please, justify this transplant experiment and describe accurately the experimental design, because in many parts of the manuscript is unclear if all the panels were transplanted or not, or if all the panels were cleaned before the transplant or not. Furthermore, in the “materials and methods” section is reported that all transplanted panel were previously carefully cleaned, thus I really cannot understand the scope of this movement of panels between sites, because in my opinion is equal to transplant bare panels, no colonized by organisms. I encourage the author to clarify this aspect in all the parts of the manuscript (abstract, introduction and methods). There are just few examples of transplanted experiments of fouling communities, but they all include the transplant of panels colonized and not cleaned (e.g., Gestoso et al. Mar. Pollut. Bull. 119, 72–80; Tamburini et al., 2022 Marine Pollution Bulletin 182: 113961).

Additional specific comments are listed here below:

-Lines 150-153: It is really difficult to understand the structure of the PVC panels used, I would suggest to include an image or a scheme of the structure with the frames described. 

-Line 158: please, briefly specify the protocol followed.

-Line 170: I would suggest to run a PERMANOVA test to analyze the structure of the fouling community, using the abundance dataset, and assess differences among treatments.

-Lines 188-195: These considerations must be statistically verified.

-Line 196: What is the meaning of IS700? And later IS900?

-Figures 6-9: Specify the meaning of the letters in the figures, both letters included for the ANOVA analyses and in the axes (U, C, G).

-Line 317: At that point it is not clear if no-transplanted panels were cleaned or not when transplanted panels were moved. If not, it’s obvious that the succession of fouling communities is different between transplanted and no-transplanted one. Furthermore, in materials and methods you do not have specified if a set of panels remained in the original site or not. Please, improve the description of the experimental design in the methods section and clarify the results.

-Line 461: Not all alien species are ecosystem engineers, I would suggest to delete it.

Author Response

Thank you for the review. Your comments and recommendations were insightful and addressing them has improved the manuscript. I have added detail to the methods to clarify what we did in the experiment. In addition, I have added an extra conclusion emphasizing the importance of continuing to groom surfaces to maintain clean hulls. One of the hypotheses was to look at the conditioning of surfaces after husbandry. As we show that grooming and cleaning leave behind some kind of cue that affects recruitment, this was an important point and why we performed the transplant.

We will address the point by point comments below:

• Lines 150-153: I added images of the two static immersion barges and a diagram showing the set up of the frames to clarify how panels are immersed.
• LIne 158: I added a short sentence describing the ASTM method.
• Line 170 & 188-195: The community information was included to describe the two sites. Care was used to avoid language that suggested we did statistics on these data. Specific differences were examined separately with SIMPER and Anova, and shown in break out graphs. Further statistical analysis is beyond the scope of this manuscript and does not address the specific hypotheses.
• Line 196: A paragraph was added to the methods describing the coatings in greater detail and defining the acronyms (Intersleek 700 = IS700; Intersleek 900 = IS900).
• Figures: I added sentences to the figure captions defining the treatments, and explaining the time notations. An additional sentence was added to explain that the letters over the bars denote statistical significance.
• Line 317: Sentences were added to the methods clarifying that one set of replicates was transplanted and one remained in the original location. I also clarified that all panels were cleaned completely prior to the transplant, regardless of whether they moved or stayed.
• Line 461: While I agree that not all NIS are ecosystem engineers, I was referencing the conclusions from the Bax paper. In order to address your concerns and still maintain the connection to the Bax paper, I added invasive species to the sentence.