This manuscript provides interesting and important insight into the potential practical extension of valvometry beyond ecotoxicology to reveal the impacts of physical water conditions on biota in their environment. It also demonstrates alternative means of assessing behaviour in such systems. It is well written and quite thorough. However, I think that it would benefit from some minor alterations, partly through some restructuring, some shortening or additional information, and occasional clarification of language.

In the Abstract, I think that you could mention what was done in a more logical order, as it was the laboratory experiments that helped inform what was best to do in the following field experiment – i.e. include the sentence “The experimental results demonstrate that stuck mussels produce signals…” before “Subsequently, we examined the response of…”. I would also recommend changing the word “stuck” to “immobilized” throughout the manuscript, as the former sounds too colloquial.

It seems that the Materials and Method section could be written more concisely. Make sure that when you first refer to the field site, you also then call it the “Enterprising site” (as it appears in Fig. 1), and consistently use a single term for the site throughout, as it seems strange to switch between multiple terms for the same thing later in the manuscript. You could also perhaps give a grid reference of the site. It may also be sensible to use a different shade for Italy in Fig. 1, as it seems too similar in shade to that of the Lakes. The letters seem to be missing from Fig. 2. I recommend you label each animal as it is numbered – i.e. say “FM4 did…” rather than “the FM numbered 4 did…”. As you effectively used two cohorts of FMs, 8 in the laboratory and 13 in the field, I would recommend each having its own number or letter – perhaps call animals in laboratory FMa to FMh and animals in field FM1 to FM13. I think there is no need to include Table 1, as these details are clear enough in the text, and are not so extensive as to necessitate a table. Make sure you refer to the discharge in L/s, with a space between the number and unit – i.e. at L157, 158, 159, 161. It would probably be best to consistently use the term, “vertical rods”, rather than changing to “bars” occasionally. When mentioning the probe, I think it is unnecessary to provide the resolution and accuracy. I find L173-188 needlessly long. I think the important details could easily be said more succinctly. I also think it is unnecessary to include the equation for what is essentially only converting values to percentage opening using the minimum and maximum voltage readings. I think it is important to make clear that the scale was assumed to be linear. Could you provide a little more detail on the Matlab function/mean (L194) – I presume it is a running mean calculated within an individual over a certain time frame? Perhaps you could label where the multiparametric probe is positioned in Fig. 3. I also wonder whether you could include a little more detail and justification for detrending and removal of step changes, otherwise it could sound arbitrary. I think you should include key dates, such as when you collected specimens, when you attached sensors, how long after attachment of sensors that you started work, as it is important to know the time frames. I also think you should include temperatures the specimens were maintained at for completeness.

I think the Materials and Method section should be slightly restructured to provide details in a more logical way, and avoid repetition as far as possible. I think you can start as you have with the site choice, how that dictated choice of mussel species for investigating both in the laboratory and in the field. Then give the details of the Hall sensor method. Then I think you should give the details of the conversion of the mV readings, then highlight that you were particularly interested in the opening amplitude – that you extracted the median opening for multiple specimens and looked at the mean within each specimen, with Matlab determining abrupt changes – and the frequency, using CWT, including an explanation of that. Then describe the laboratory work, explain its purpose was to determine if there were differences between free and immobilized mussels because only immobilized mussels could realistically be used in the field. Then give details of what the work in the river entailed. I think you need to make it clear that you deliberately recorded behavior in the field during a flood event here too.

L250 “The difference…” – this sentence explains the observation, which is a point that should really be saved for the Discussion section.  Make sure you consistently use either “pseudo-frequency” or “pseudofrequency” but not both. In Fig.s 4 and 5, it would be best to have a little more detail than just “Magnitude” for the scalograms. I think in the Results section, the observation that the immobilized laboratory mussels returned to baseline behavior quicker should be highlighted, but inferring that this suggests they adapted quicker (and what this suggests) should be kept for the Discussion. L273 – I wonder if you should say consistent “responsiveness” rather than “responses”, as the actual response of free and immobilized were only similar through CWT analysis (though of differing duration) and rather different in terms of opening amplitude. Also, I recommend saying it “supported the suitability” rather than “possibility” (L274). I think the dates should be mentioned in the Materials and Method section rather than here, although it is obviously fine to mention the missing data/technical issue here. Also, probably best to refer to the shift as “marked” rather than “significant” unless significance tests were done. I would avoid classifying the behavior and explaining the observations (“state of resting”, “regular valve movements as expected during respiration and filtration”, “displayed avoidance behavior” and “trying to restore their normal activity”) and save explanation and classification of behaviour for the Discussion. I also think that it would be best to slightly change the structure, i.e. to first mention the observations in the hydrodynamic conditions, then mention the behavioral observations, and then to tie the observations within both together, rather than giving details sporadically. The details of which mussel(s) were excluded from Fig. 4 b-d should be mentioned in the caption for that figure.

In the Discussion, make sure you highlight all the key findings and explain observations where appropriate – first from the laboratory, then the field. As mentioned before, I think “responsiveness” may be more appropriate than “responses” (in L325). Details of method/calculation of the incipient discharge (L345-359) should be included in the Materials and Method section, and the outcome of the calculation included in the Results, with only its implications mentioned here.  I think the details about logistical challenges (L360-366) should be mentioned in brief, and only after the findings. After that I would include a reiteration of the particular value of the findings, specifically how it extends the use of valvometry for hydrodynamic factors (including ideas mentioned in Introduction). Then you can include the bullet points. I think the Supplementary Figures should all have been referred to in the Results section and no figures should really be referred to in the Discussion. I presume it should read as “d₉₀” in L351, and I presume it should not read “0.2[-]” in L354. I presume that a separate bullet point starts  at “continuous wavelet transform proves…” in L388.

In the Supplementary Figures, I think the plots should have labels for the FM from which the data was taken (as in Fig. 5a). I presume it would be better for the captions of Fig.s S3 and S4 to refer to the “removal of step changes”. I also think it might be better for what appears as Fig. S2 to instead appear after what is currently Fig. S3, and for the supplementary figures to all be mentioned in the Results section.

Make sure that you use a consistent version of English. I noticed that most words used US English spelling, but a few used the British version of “behaviour” and “set-up” too.

The manuscript is generally easy to understand. It may be beneficial for a native English speaker to read through it to make minor changes. Here are some possible changes that would make it easier to read as written English:

“FMs” should appear as “FMs’” in L3,5, in L189 (second occurrence), in L262 (second occurrence), and as “FM” in L15,135,169, in L189 (first occurrence), and L193,197,226,249,268

“have been” should be changed to “were” in L4,234, and “has been” should be changed to “was” in L109,225,236,239,373,374

L12 – change “thus confirming” to “consistent with”

L34 – format of source seems to be inconsistent

L40 – change “temporal horizons” to “time frames”

L42 – little unsure of what you mean by “event-time-scale”

L55 – reference order should be 1979 then 1981

L60 – remove the extra bracket on the reference

L65-66 – change the end of the sentence (“become important and unique”) to something that does not suggest its use before was neither of these things, such as by saying “enhance the importance and highlight the unique insight of this approach”.

L69-70 – change “was” to “were”

L71 – remove “be”

L76 – change “was” to “is”

L93 –  remove “is”

L95 – change “final” to “overall”, so it’s clear that this is the main aim of the work, not the last in a list of aims

L114 – add comma after “(Figure 1)” and change to “for the laboratory and in situ installation”

L126 – presume should read “Honeywell”

Make sure that when giving dimensions, you use a consistent format in spacing, i.e. L126 and 127

L148 – insert “considered” before “necessary”, as it was a conscious decision

L164 – change “was necessary” to “was deemed necessary”

L244 – remove “occurred” and put a comma before and after “10 hours after the start of the experiment”

L247 – change “various” to “varied” and “those from” to “that of”

L248 – change “are not” to “appear not to be” as it is speculative

L263 – change “prompted” to “promptly”

L264 – change “pseudo-frequency” to “pseudo-frequencies”