The Diversity, Structure, and Development of the Epibiont Community of Paramuricea clavata (Risso, 1826) (Cnidaria, Anthozoa)

Round 1

Reviewer 1 Report

 

The article by Canessa et al. deals with a the sometimes forgotten topic of epibiontic communities, focusing on those occurring on the endangered gorgonian Paramuricea clavata (an emblematic species from Mediterranean waters). Particularly, the authors focus on stablishing possible link between epibiontic communities’ prevalence and diversity on P. clavata in regards to the effects by both heatwave events as well as anthropogenic pressures, such as fishing or SCUBA. The authors work on a topic of increasing importance, VME health status, with the added dimension of working on an MPA where artisanal fisheries still operate. The article’s methodology is sound, it is well-written and its results are properly discussed; references are up to date and they are aware and reference the main limitations of their study, which regards the temporality of the observation.

Below are some minor suggestions and comments I believe could help enrich their work:

Lines 41-42: While no one would discuss the validity of the statement made by the authors in these lines, I’d still suggest them to add at least a few references referencing the impact the mentioned activities have in gorgonian populations.

Lines 54-56: This lines as they are now, break a bit the flow of the paragraph. I’d suggest the authors to rewrite them as in “large population of P. clavata, which forest settle both on Tavolara Island’s limestones and Tavolara Channel’s granitic outcrops [26, 27]. Said population has been widely studied in recent years, with several surveys…” or similar.

Line 60: substitute ‘regards’ for ‘only includes/covers’

Lines 68-71: I’d suggest the authors to develop a bit more on the establishment and legal status of the MPA itself, as I think will provide a historical perspective to readers whom might not be familiar with the area.

Line 85: Suitable perspective is a bit ambiguous, the authors should properly define which perspective they used (e.g. frontal view).

Line 105. Specific examples are given for other macrobenthic taxa except for bryozoans. I’d suggest the authors to also mention the most abundant accompanying species for as long as they were able to identify them to at least genus level.

Line 128: The authors followed the ICZN code recommendation of citing the authorship for a species the first time is mentioned in the text, something not many researchers do, and which I personally appreciated. I’d then suggest to also add the authorship for Savaglia savalia, which is only mentioned in this caption.

Lines 257-259: The authors later assume in the sentence the reader knows the Medes Island is an MPA, although this is not properly stated. I’d suggest the following (highlighted) changes: Medes Islands MPA (Catalan Sea) indicated that between 10% and 33% of the colonies of unprotected populations were partially colonized by epibionts, whereas only from 4% to 10% of the populations in the MPA were affected…

Lines 303-307: Although I agree with the authors reasoning and conclusions in this section, they do not have any concrete evidence on the recurrence and extent of the damage artisanal fisheries have into particular gorgonian individuals. One way to strengthen this conclusion would be to place it after line 326 (See comment below)

Line 326. The authors state that "...the appearance of the opportunistic tube-dwelling polychaetes Filograna/Salmacina spp. after summertime is a proof that fisheries rather than scuba might be the main factor to cause epibiosis in the area", yet they do not provide any reasoning for such. I assume that perhaps fishing practices mostly occur in summer in the area, prior to this increase in Filograna? If so, this is highly interesting, and could help strengthen the linkage between artisanal fishing practices and calcareous epibionts (currently in lines 303-307). Yet it needs to be further developed for readers not familiarized with the area to properly follow.

Lines 359-364: I’d suggest the authors to consider this as a conclusions section, setting it aside from the rest of the discussion.

Finally, I want to congratulate the authors for a sound and compelling work, and encourage them to continue working on the topic.

 

Author Response

WE WOULD LIKE TO THANK THE REVIEWER FOR THE USEFUL SUGGESTIONS.

THE ANSQUER TO THE COMMENTS ARE HERE BELOW: 

 

Lines 41-42: While no one would discuss the validity of the statement made by the authors in these lines, I’d still suggest them to add at least a few references referencing the impact the mentioned activities have in gorgonian populations.

WE ADDED A REFERENCE

Lines 54-56: This lines as they are now, break a bit the flow of the paragraph. I’d suggest the authors to rewrite them as in “large population of P. clavata, which forest settle both on Tavolara Island’s limestones and Tavolara Channel’s granitic outcrops [26, 27]. Said population has been widely studied in recent years, with several surveys…” or similar.

OK DONE

Line 60: substitute ‘regards’ for ‘only includes/covers’

OK DONE

Lines 68-71: I’d suggest the authors to develop a bit more on the establishment and legal status of the MPA itself, as I think will provide a historical perspective to readers whom might not be familiar with the area.

OK DONE

Line 85: Suitable perspective is a bit ambiguous, the authors should properly define which perspective they used (e.g. frontal view).

OK DONE

Line 105. Specific examples are given for other macrobenthic taxa except for bryozoans. I’d suggest the authors to also mention the most abundant accompanying species for as long as they were able to identify them to at least genus level.

OK DONE

Line 128: The authors followed the ICZN code recommendation of citing the authorship for a species the first time is mentioned in the text, something not many researchers do, and which I personally appreciated. I’d then suggest to also add the authorship for Savaglia savalia, which is only mentioned in this caption. 

OK DONE

Lines 257-259: The authors later assume in the sentence the reader knows the Medes Island is an MPA, although this is not properly stated. I’d suggest the following (highlighted) changes: Medes Islands MPA (Catalan Sea) indicated that between 10% and 33% of the colonies of unprotected populations were partially colonized by epibionts, whereas only from 4% to 10% of the populations in the MPA were affected…

OK DONE

Lines 303-307: Although I agree with the authors reasoning and conclusions in this section, they do not have any concrete evidence on the recurrence and extent of the damage artisanal fisheries have into particular gorgonian individuals. One way to strengthen this conclusion would be to place it after line 326 (See comment below)

THIS EVIDENCE IS DERIVED BY DIRECT OBSERVATIONS ON ENTANGLED COLONIES. WE HAVE CLARIFIED THE SENTENCE

Line 326. The authors state that "...the appearance of the opportunistic tube-dwelling polychaetes Filograna/Salmacina spp. after summertime is a proof that fisheries rather than scuba might be the main factor to cause epibiosis in the area", yet they do not provide any reasoning for such. I assume that perhaps fishing practices mostly occur in summer in the area, prior to this increase in Filograna? If so, this is highly interesting, and could help strengthen the linkage between artisanal fishing practices and calcareous epibionts (currently in lines 303-307). Yet it needs to be further developed for readers not familiarized with the area to properly follow.

THE SENTENCE WAS UNCLEAR. WE HAVE REARRANGED THE TEXT

Lines 359-364: I’d suggest the authors to consider this as a conclusions section, setting it aside from the rest of the discussion.

THIS IS A MATTER OF OPINION. WE PREFER MAINTAIN THIS PARAGRAPH WITHIN THE DISCUSSION SECTION. NEVERTHELESS, IF THE EDITOR ASKS FOR THIS CHANGE, NO PROBLEMS

Finally, I want to congratulate the authors for a sound and compelling work and encourage them to continue working on the topic.

THANK A LOT FOR THE APPRECIATION OF OUR WORK

Reviewer 2 Report

Attached are my comments.

 

 

Comments for author File: Comments.pdf

Author Response

Please find the response to the reviewer's comment in the attached PDF. 

We thank for the suggestions.

Author Response File: Author Response.pdf

Reviewer 3 Report

see attached comments

Comments for author File: Comments.pdf

Author Response

WE REALLY APPRECIATED ALL THE REVIEWER'S COMMENTS AND SUGGESTIONS. HERE BELOW THE ANSWERS TO THE COMMENTS:

 

Review of: “Diversity, structure and development of the epibiontic community of Paramuricea clavata (Risso, 1826) (Cnidaria, Anthozoa); Martina Canessa, Ilaria Amedeo, Giorgio Bavestrello, Pier Panzalis, Egidio Trainito.

This study makes a significant contribution to our understanding of an important yet poorly understood habitat. Deeper water coral habitats are often difficult to sample yet may provide an important structural community and serve as foundational systems.

THANK A LOT FOR APPRECIATION

This study utilized photographs from SCUBA dives in a study area 35-55m depth, utilizing the photographic images to estimate the percent cover of various epibionts. While SCUBA is one of the primary methods for sampling at these depths, there have been recent discussion in the literature and at conferences on the need to clearly take into account the limitations of this technique when interpreting the data for percent or actual abundance patterns, especially for deeper areas such as the 55m deeper depth indicated in the study site description for this research where time limits may prohibit extensive quality control procedures. The manuscript may benefit by briefly addressing some of the following aspects of the methodology:

- What measures were taken to ensure angle and distance to object did not vary among photos in a manner that may impact the ability to accurately assess percent cover (e.g. visual distortion effects with increasing angles)? This may be especially challenging in deeper areas where bottom time for SCUBA censuses may be limited.

THE PERCENTAGES ARE CALCULATED NOT AS ABSOLUTE VALUES, BUT AS RELATIVE VALUES ​​FOR EACH COLONY, AND THEREFORE ANY DISTORTION DOES NOT AFFECT THE ESTIMATION. CLARIFIED IN THE TEXT.

- How was the 3-dimensionality of the structure taken into account in determining overall percent cover (e.g. some areas hidden from view by the structural complexity)? The excellent photographic information provided in the manuscript indicates considerable 3-dimentsionality even with a planar target species.

THE THREE-DIMENSIONAL DEVELOPMENT OF THE EPIBIONTS WAS NOT CONSIDERED AS OUR FOCUS WAS THE PERCENTAGE OF THE INVOLVED COLONIES THAT, GENERALLY, HAVE A PLANAR DEVELOPMENT. CLARIFIED IN THE TEXT.

- The author compared their photographic information to a photographic archive. Are there any differences in techniques that may alter the accuracy of comparing percent abundances among these data sets (e.g. type of photography, greater accuracy because of shallow sites, some of the considerations mentioned above)? Also, to what extent has percent cover been used for some species and percent abundance for others?

ALL THE IMAGES PRESENT IN THE ARCHIVE AND USED IN THE ANALYSIS WERE MADE WITH THE SAME TECHNIQUE. TO EVALUATE THE ABUNDANCE OF AN EPIBIONT WE USED THE PERCENT OF P. clavata COLONIES IN WHICH A SPECIES APPEARS (RECURRENCE).  THE PERCENT COVER WAS EMPLOYED EVALUATE THE EXTENT OF A P. clavata COLONY IN THE EPIBIOSIS. MOREOVER, THE COVER WAS USED TO DESCRIBE THE TEMPORAL DEVELOPMENT OF EPIBIOSIS ON A SINGLE COLONY. SOME CLARIFICATIONS IN THE TEXT

- How accurate were the species identifications based upon the photographic images? Some taxa may not be accurately identified by this approach unless accompanied by verification from collections. While very understandable, comparison of large taxonomic groups such as hydroids to species level patterns presents some challenges in understanding the relation of overall diversity to community dynamics.

WE HAVE A DEEP EXPERIENCE IN THE SPECIES IDENTIFICATION FROM UNDERWATER IMAGES. WE CONFIRM THAT SPECIES IDENTIFICATIONS ARE ACCURATE. WHEN THE IDENTIFICATIONS WERE NOT POSSIBLE WE USED HIGHER TAXA (E.G. HYDROZOA). IT IS CLEAR THAT OUR EVALUATION  OF DIVERSITY IS UNDERESTIMATED. THIS STATEMENT WAS INCLUDED IN THE DISCUSSION

- Addressing the above aspects in the methodology section, which is currently somewhat limited, may greatly enhance the ability to compare the results of this study to other research.

WE AGREE WITH THIS SUGGESTION AND WE HOPE TO HAVE ENHANCED THE DESCRIPTION OF OUR METHODOLOGY

In lines 172-173, the authors suggest a facilitative model of succession (later species “need” earlier species to become established). It has been well-documented that a tolerance model of succession (based upon recruitment dynamics and life history characteristics without later species requiring earlier ones to become established) can also lead to a predictable sequence.

In lines 338-340 the authors suggest that the epibiont patterns indicate that these species “cooperate” rather than compete. I am not sure there is sufficient information to make this suggestion. A founder-controlled system with a non-dominance hierarchy can lead to the same patterns without having significant mutualisms dominating the system.

OK, WE AGREE WITH THE REF SUGGESTIONS THAT WE INCORPORATED IN THE TEXT