“JNCC would like to register as an interested party for the Mona Offshore Wind Farm DCO application/examination. JNCC are statutory advisors to the UK Government and devolved administrations on issues relating to nature conservation in UK offshore waters (beyond the territorial limit). Our key areas of interest are birds, marine mammals and benthic receptors, as well as Marine Protected Areas, which may be impacted by the Mona Offshore Wind Project. Below we include our advice in relation to the above project, which we will separately submit to [email protected]. Mona Offshore Wind Project Development Consent Order Application – Environmental Statement and Management Plans – EN010137 Thank you for consulting JNCC on the Mona Offshore Wind Project Development Consent Order (DCO) Application including the Environmental Statement (ES) and Management Plans. Notification of acceptance for examination by the Secretary of State for Energy Security and Net Zero was received on 2 April 2024. The advice contained within this minute is provided by JNCC as part of our statutory advisory role to the UK Government and devolved administrations on issues relating to nature conservation in UK offshore waters (beyond the territorial limit). We have subsequently concentrated our comments on aspects of the documents that we believe relate to offshore waters and defer to comments provided by Natural Resources Wales Advisory (NRW-A) for aspects relating to inshore waters. The advice below relates to marine ornithology, marine mammals, and offshore benthic ecology and is captured under the following headings:  Overarching comments on the Environmental Statement  Marine ornithology comments  Marine mammal comments  Benthic ecology (offshore) Overarching comments on the Environmental Statement The following documents were reviewed in providing this response: Environmental Statement:  Volume 1, Chapter 3: Project Description  Volume 1, Chapter 5: Environmental Impact Assessment Methodology  Volume 2, Chapter 1: Physical Processes  Volume 2, Chapter 2: Benthic subtidal and intertidal ecology  Volume 2, Chapter 4: Marine mammals  Volume 2, Chapter 5: Offshore ornithology  Volume 2, Chapter 11: Inter-related Effects – Offshore  Volume 5, Annex 3.1: Underwater sound technical report  Volume 5, Annex 5.1: Cumulative effects screening matrix  Volume 5, Annex 5.2: Transboundary impacts screening.  Volume 6, Annex 1.1: Physical Processes Technical Report  Volume 6, Annex 2.1: Benthic Subtidal and Intertidal Ecology Technical Report  Volume 6, Annex 4.1: Marine mammal technical report  Volume 6, Annex 5.1: Offshore ornithology baseline characterisation report  Volume 6, Annex 5.2: Offshore ornithology displacement technical report  Volume 6, Annex 5.3: Offshore ornithology collision risk technical report  Volume 6, Annex 5.5: Offshore ornithology apportioning technical report  Volume 6, Annex 5.6: Offshore ornithology population viability analysis technical report  Volume 8, Annex 2.2: Climate change risk assessment Habitat Regulations Assessment (HRA):  Stage 1 Screening report  Stage 2 Information to support an Appropriate Assessment  Part 1, Introduction and background  Part 2, Special Areas of Conservation (SAC) assessments  Part 3, Special Protection Areas and Ramsar sites Assessments  HRA integrity matrices  Marine Conservation Zone Screening Report Offshore Plans:  Mitigation and monitoring schedule  Outline underwater sound management strategy  Outline offshore operations and maintenance plan  Measures to minimise disturbance to marine mammals and rafting birds from transiting vessels  Outline marine mammal mitigation protocol  Offshore In-Principle Monitoring Plan  Mona Array Area – Site Characterisation Report  Offshore Cable Corridor Site Characterisation Report Throughout the Environmental Statement and DCO documentation there is little distinction between inshore and offshore, distinguished by the 12nm/territorial waters limit. Given the remit of Statutory Nature Conservation Bodies (SNCBs) is divided based on this factor it would be helpful to have impacts broken down into these remits. In particular, it would have been useful to have this delineation identified on all the maps provided. Marine ornithology comments The following documents were reviewed in providing this response: Environmental Statement:  Volume 2, Chapter 5: Offshore ornithology  Volume 6, Annex 5.1: Offshore ornithology baseline characterisation report  Volume 6, Annex 5.2: Offshore ornithology displacement technical report  Volume 6, Annex 5.3: Offshore ornithology collision risk technical report  Volume 6, Annex 5.5: Offshore ornithology apportioning technical report  Volume 6, Annex 5.6: Offshore ornithology population viability analysis technical report HRA:  Stage 1 Screening report  Stage 2 Information to support an Appropriate Assessment  Part 3, Special Protection Areas and Ramsar sites Assessments  HRA integrity matrices Overall comments We disagree with several elements of the assessment to offshore ornithology within the ES and the HRA. In addition, there are multiple errors within the tables and text, and errors when using values in subsequent stages of the assessment. Many aspects of the assessment are difficult to follow what has been done or where values have come from. Due to these disagreements, errors, and lack of clarity, we do not have confidence in the results, nor are we able to agree with the overall conclusions, either within the EIA or the HRA, particularly with regards to Skomer, Skokholm and the Seas off Pembrokeshire/Sgomer, Sgogwm a Moroedd Penfro Special Protected Area (SPA). Aspects of JNCC advice appear to have been misinterpreted, for instance foraging values and agreements and disagreements on breeding Biologically Defined Minimum Population Scales (BDMPS) reference populations. Some aspects of JNCC advice also appear to have been taken on board in some circumstances, then not taken on board in other circumstances, despite being agreed to during pre-application meetings and correspondence. For instance, using a range of displacement rates in the ES, but specific displacement rates being used in the HRA. We advise that the below disagreements, errors, and unclear aspects are addressed through submission of revised documents related to offshore ornithology. We have identified errors to the best of our ability with the time available, but this may not be an exhaustive list of all errors, and we recommend that a full and thorough check of all tables and in-text values is conducted. JNCC can only comment on sites for which we have jurisdiction (UK marine sites wholly or partly in waters beyond 12nm). We note that NRW and Natural England (NE) have been involved in pre-application discussions and defer to those agencies on their respective sites. We also note that a number of SPAs in Irish and Scottish waters are screened in at Likely Significant Effect (LSE), and recommend consultation with the relevant nature conservation advisers. Volume 2, Chapter 5: Offshore ornithology We disagree with the use of the term ‘JNCC avoidance rates’, or similar, to describe the Ozsanlav-Harris report. Although Ozsanlav-Harris et al. (2023) is a JNCC report, it does not in itself constitute our recommended avoidance rates. Referring to it as ‘JNCC avoidance rates’ incorrectly gives the message that JNCC advise use of every number in the report as it appears, which is not necessarily the case. Our advice on implementation of the results of Ozsanlav-Harris et al. (2023) is included in the joint SNCB guidance note on Collision Risk Modelling (CRM). This uses the rates from Ozsanlav-Harris et al. (2023), but species grouping is an important aspect of this. This information is contained within advice which Natural England provided on 7 July 2022 directly to the Applicant and is also used. Those rates should be regarded as and named joint SNCB avoidance rates, whilst the Ozsanlav-Harris et al. (2023) should be named as Ozsanlav-Harris et al. (2023) rates. This has been iterated to Mona Offshore Wind during the Expert Working Group (EWG) several times, for example during the 6th Ornithology EWG held on 19 October 2023, and within JNCC comments provided on 23 November 2023 on the minutes of the 6th Ornithology EWG. The applicant’s response to JNCC comments on the minutes of the 6th Ornithology EWG meeting state “Applicant response: Thank you – we have updated the reference throughout our documents” yet clearly this is not the case. This comment also applies to the HRA Integrity Matrices document and Volume 6, Annex 5.5: Offshore ornithology apportioning technical report. Table 5.13 and Table 5.14: Seasonal definitions differ across tables and documents, so it is not clear which is being used in each circumstance it is used. Sections 5.3.9.10 to 5.3.9.12: We maintain our disagreement over the breeding season BDMPS reference population used for the alone assessment as has previously been advised. In the offshore ornithology EWG07 meeting, we agreed to disagree on EIA breeding reference population "RB - We will need to “agree to disagree” on other species but for gannet and Manx shearwater the lower number should be used", the lower value meaning whichever is lower between the SNCB approach and the applicant's proposed approach. Our agreement log maintains our disagreement with the proposed approach. The Applicant states in Section 5.3.9.12 of Volume 2, Chapter 5: Offshore ornithology that "During the seventh EWG meeting (held 8 December 2023), it was agreed that for the project alone assessment, foraging range populations could be used, however if the foraging range population is greater than the regional seas populations (BDMPS from Furness, 2015) then impacts would also be assessed against this population." This doesn't quite reflect the discussion or minutes of the EWG07 meeting. Our advised approach remains to consider breeding adult birds at colonies within the relevant BDMPS in which the project is located, plus the immatures associated with those colonies. Data should come from the tables in Appendix A of Furness (2015) for both breeding adults and immatures. Table 5.22: We welcome the seasonal restriction on installation of offshore cables throughout the wintering period for works inside the Liverpool Bay SPA, and that this will be secured through DCO requirement. However, it is unclear whether this includes a buffer around the SPA. Disturbance from vessels have been demonstrated for a number of species, and the zone of influence of this type of disturbance has been shown to extend to 2km for red-throated diver and 2.5km for common scoter. JNCC would recommend that the exclusion of operating within the Liverpool Bay SPA during the period stated is extended to within 2.5km of the SPA boundary. Table 5.25: The incorrect Mean Seasonal Peak abundance appears to have been calculated for Atlantic puffin in the non-breeding season. Comparing Volume 6, Annex 5.1: Offshore Ornithology Baseline Characterisation Technical Report, Volume 6, Annex 5.2: Offshore Ornithology Displacement Technical Report, and Volume 2, Chapter 5: Offshore ornithology, suggests that the Mean Seasonal Peak was 22 for Atlantic puffin during the non-breeding season. Therefore, the predicted displacement mortalities during both the non-breeding season and annually may be incorrect. This may then have implications for the subsequent assessment, such as the need for apportioning of impacts, and LSE screening. We recommend a thorough review of the Mean Seasonal Peak calculation and the need for any subsequent assessment. Sections 5.7.2.105 to 5.7.2.106: We note the lack of Population Viability Analysis (PVA) for common guillemot against the reference population relevant to the 1% baseline mortality trigger prompting the need for a PVA within the ES. It is acknowledged that during the breeding season the worst-case scenario of 70% displacement and 10% mortality, an increase in baseline mortality greater than 1% is predicted for common guillemot. It is then stated that PVAs have been carried out on two Sites of Special Scientific Interest (SSSI) breeding colonies. It is not clear why impacts have been assessed against those colony populations, when the reference population against which the predicted displacement mortalities were assessed was the foraging range breeding BDMPS population. Therefore, we would expect to see a PVA carried out for the breeding season alone impact mortalities against the breeding season reference population. Section 5.7.5: We disagree with the use and presentation of only mean or central collision estimates throughout. The Confidence Intervals associated with collision estimates should also be provided and taken through the assessment to assess the full range of potential effects. This comment also applies to the HRA Integrity Matrices document, Section 1.2.5, and the HRA Stage 1 Screening Report document, Section 1.4.6. Section 5.7.5.13: We note the lack of PVA for breeding season collision impacts to great black-backed gull. Predicted collisions are above 1% baseline mortality during the breeding season, yet a PVA have not been carried out. Therefore, we would expect to see a PVA carried out for the breeding season alone impact mortalities against the breeding season reference population. Tables 5.38; 5.39; 5.42; and 5.44: For some species it would appear, though it is unclear, that impacts for a particular month which is within two BDMPS seasons have been split between the two seasons. Clarity is required if this is the case, and when this has been undertaken, and whether this is an appropriate use of the survey data, for instance when within a month the survey was carried out. For example, if data was calculated at one end of a month, is it appropriate to halve this value and associate one half with the other end of the month? Tables 5.38; 5.39; 5.42; and 5.44: If it is the case that impacts for a particular month which is within two seasons have been split between the two seasons, it is unclear whether this approach is appropriate when put into context of seasonal reference populations (e.g. Furness (2015)). Do the seasonal reference populations used also split populations in the one month between seasons? Section 5.9: We maintain our disagreement over the approach to cumulative (EIA) and in-combination assessments (HRA), and specifically the inclusion of projects with unquantified levels of impact (either because modelling techniques have changed, or their impacts were not quantitatively assessed), and this disagreement has been raised in Preliminary Environmental Information Report (PEIR) responses and during the EWGs. In October 2023, the SNCBs supplied bespoke advice to the Mona, Morgan generation and Morecambe generation projects (Proposed methodology for ‘gap-filling’ the Irish Sea R4 cumulative & in-combination assessments, circulated by Natural England), providing a suggested approach to filling in gaps in data on impacts from relevant projects for cumulative/in-combination assessment. The Applicant has not followed this approach and has presented a qualitative approach for the projects with no data. We do not consider that the qualitative assessments presented by the Applicant are sufficient and do not consider that conclusions can be drawn without reasonable scientific doubt, regarding the accumulating scale of impact to some species. We therefore reiterate that our advice for a pragmatic method to address the lack of impact assessments for a number of historical Offshore Wind Farms (OWFs) in the region remains as detailed in the original SNCB advice. Sections 5.9.2; 5.9.3; and 5.9.4: In the cumulative assessment, the abundance estimates at Erebus offshore wind farm are incorrect for several species. This was also the case in the Section 42 PEIR, and JNCC responded to these errors in our Section 42 PEIR response. However, the same errors remain. The abundance estimates to use should be those within Table 5-1 for common guillemot and Table 5-3 for Atlantic puffin in the Project Erebus: Supplementary Environmental Information Addendum Report (2022). The abundance estimates for gannet should be those within Table 23 of the Erebus: Offshore Ornithology 11.4 Technical Appendix – Displacement Analysis (2021). The abundance estimates for kittiwake should be those within Table 18 to 20 of the Erebus: Offshore Ornithology 11.4 Technical Appendix – Displacement Analysis (2021). Sections 5.9.3 and 5.9.4: In the cumulative assessment, the collision estimates for gannet at Erebus are incorrect. The collision estimates to use should be those within Table 5-31 of the Project Erebus: Supplementary Environmental Information Addendum Report (2022). Sections 5.9.2; 5.9.3; and 5.9.4: Impacts in the cumulative tables often do not add up to the totals at the foot of the tables, and have multiple other errors in them, such as figures apparently attributed to the wrong wind farms, seasonal impacts not adding up to annual impacts. Section 5.9.3: For the ES cumulative assessment, it appears that collision estimates from other offshore wind farm projects have been adjusted to account for different avoidance rates. However, it is not stated that this has been done, nor how this has been done. Therefore, we cannot replicate the findings, or determine whether the method or results are correct. Volume 6, Annex 5.5: Offshore ornithology apportioning technical report Table 1.4: The last column in Table 1.4 should be titled “Proportion of adult birds (%)” not “Proportion of immature birds (%)”. Section 1.3.3: No information is provided on the number of adults and immatures identified from Digital Aerial Surveys (DAS). Without an understanding of the number of birds identified to age classes, as a proportion of the total number of birds (per species), it is hard to know whether a representative sample was identified, and whether this was appropriate to use when applying a ratio of adults and immatures to unidentified birds. Section 1.3.3: We disagree with the calculation of kittiwake age classes. This approach was not raised by the applicant during EWG meetings or subsequently, and therefore JNCC has not agreed to this approach. The Hornsea Offshore Wind Farm Project Two approach to apportioning to age class referred to in Section 1.3.3.5 relies on reliable counts of first year birds, i.e. in the case of kittiwake first summer birds which by August of that year have largely transitioned to adult plumage and therefore indistinguishable from adults. Therefore, the identification rate of first summer kittiwake is questionable and calculations derived from this, for example, applying survival rates to define an age class structure is also questionable. It is noticeable that more recent projects such as Hornsea Offshore Wind Farm Project Four and the East Anglia projects have not used this approach. Further, we advise that stable age structures are not derived using population viability analysis, and the method outlined in this report is effectively a manual version of this, which we do not recommend. We therefore disagree with the percentage of kittiwake adults and immatures in the breeding season in Table 1.6. Section 1.3.3: We disagree with the methods of apportioning impacts between adults and immatures during the non-breeding season. We advise that the same approach is taken as for the breeding season, as has been advised previously during EWG meetings and correspondence, by using the proportions of adults and immatures identified by surveys, and otherwise assuming all adult-type birds are adults. Section 1.3.5: We disagree with the method of apportioning impacts to SPAs during the non-breeding season. We recommend that to calculate apportion impacts to colonies in the non-breeding season, this should be based on the proportion of the SPA adult birds, across the BDMPS total of birds of all ages, for each relevant non-breeding BDMPS season, as has been advised previously during EWG meetings and correspondence. Table 1.7: It is not clear whether sabbatical birds have been removed from the assessment or not. There is suggestion that they haven't, yet the heading of Table 1.7 suggests that sabbatical rates are considered within the HRA. Volume 6, Annex 5.6: Offshore ornithology population viability analysis technical report Table 1.4: The BDMPS and baseline mortality values for great black-backed gull appear to be associated with the wrong seasons. For the annual assessment the BDMPS should be 44,753 with a baseline mortality of 4,252. For the non-breeding season, the BDMPS population should be 17,742 with a baseline mortality of 1,685. The PVA logs in Appendix A2.1 and A2.2 appear to have associated the correct reference populations per season, therefore the PVA itself appear to have used the correct values, but the values in Table 1.4 are incorrect. Table 1.12 and Table 1.13: The extremely high predicted growth rates associated with great black-backed gull are at odds with the general trend in Global and European (where non-breeding great black-backed gull in UK waters are likely to originate) and UK breeding populations being that of decline (albeit with range expansion). For example, Burnell et al. (2023) highlights the overall declines in breeding great black-backed gull in Britain and the UK since the previous national census (Seabird 2000) of -55% and -52%, respectively. England has suffered a smaller decline (-3%), with the breeding population of the Isles of Scilly increasing slightly (14%). Given the overall picture of decline, we question whether increases in population of ~12,000% predicted by the PVA would ever be realised in reality, and hence the reliability of the PVA predictions. We recommend a sense check of the PVA input and outputs before having reliance on the outputs. HRA Stage 1 Screening Report There are multiple discrepancies between the main text of the HRA Stage 1 Screening Report and the appendix tables of the same document. All values (text and tables) should be double-checked and updated where necessary. The HRA Stage 1 Screening Report provides very little information to cross reference which values from other documents have been used, and through what calculation, in order to generate results. Therefore, it is nearly impossible to follow what values have or have not been used. We strongly recommend that the HRA Stage 1 Screening Report contains a clear audit trail of what values and parameters have been used, where they have been used, and how they have been applied. Without this, we cannot confidently replicate the results, and hence we cannot have confidence in the results. Table 1.2 and Table 1.7: We disagree with the application of foraging ranges for Atlantic puffin. Although breeding season apportioning has not been carried out, our view is that it should be when using the correct Mean Season Peak value (see comment on Atlantic puffin MSP error), therefore it is important to use the correct foraging range. It is not accurate to state, in Tables 1.2 and 1.7 of the HRA Stage 1 Screening Report, that “JNCC requested (via their S42 response) that all SPAs to the north of the Mona Offshore Wind Project within 265.4km be considered for Atlantic puffin.”. In JNCC correspondence to the Applicant on 28 June 2023, we advised “We confirm that the foraging range to use for Atlantic puffin is 265.4km (MM+SD). Woodward et al. (2019) state (page 138) that “As was the case for common guillemot and razorbill, foraging distances travelled by Atlantic puffin from Fair Isle are higher than those at most other sites (RSPB dataset), although they are not as exceptional when compared to other sites as those of the other two auk species” and “Observations of birds carrying fish have been made at distances of 250km from the Faeroe Islands (Harris & Wanless 2011), offering further speculative evidence that Atlantic puffins forage at longer distances than the other auk species. Hence the distances observed from Fair Isle and Hermaness should not necessarily be considered exceptional until more data and data from additional colonies have been collected, particularly data from colonies where local prey availability may be greater”. Therefore, we advise using the generic mean max +1SD value as stated in Table 5.”. Therefore, we advised that the foraging range within Table 5 of Woodward et al. (2019) (137.1 ± 128.3 = 265.4km) should be applied to all SPAs. There is no exception to this value for Atlantic puffin. This value should be used throughout. Table 1.2 and Table 1.7: We disagree with the application of foraging ranges for common guillemot and razorbill. It is not accurate to say, in Tables 1.2 and 1.7 of the HRA Stage 1 Screening Report, that “JNCC requested via their S42 response all SPAs to the north of the Mona Offshore Wind Project within 153.7km be considered for common guillemot” and “JNCC requested via their S42 response all SPAs to the north of the Mona Offshore Wind Project within 164.6km be considered for razorbill”. We do recommend that these values are applied in certain circumstances. However, these circumstances are not “all SPAs north of Mona”, the circumstances are for all Northern Isle SPAs. Therefore, it is unclear whether the correct SPAs and other sites have been screened in with regard to Atlantic puffin, common guillemot, and razorbill. It is therefore also unclear whether the calculations in Volume 6, Annex 5.5: Offshore Ornithology apportioning technical report are correct, and subsequently, any of the values relevant to these species and SPAs in the HRA. Section 1.4.6.17: We disagree with the use of only specific displacement rates and mortality ranges in the HRA displacement assessment. We advise that the full range of displacement and mortality ranges previously advised are used and presented within the HRA to assess the full range of potential effects. It is odd that the full range of displacement rates and mortality rates have been presented and assessed within the ES, yet specific rates have been used within the HRA. Whilst we would not base our advice solely on the worst-case likely scenario, it is important to look at the range likely to scenarios in order to determine whether there is a realistic possibility of impact that would need further consideration (i.e. through Appropriate Assessment). It is important to follow the stepwise process of the Habitats Regulations Assessment process in order to systematically consider the impacts of a Plan or Project to an appropriate level. Section 1.4.6.30: While we have accepted the approach to LSE screening and Appropriate Assessment in this case, it should be noted that the LSE test is a course filter, as per our advice given during pre-application meetings, our response to the Section 42 PEIR, and as summarised in Table 1.2 of the HRA Stage 1 Screening report. The screening presented in this application has gone beyond an assessment of whether an impact pathway has the potential to compromise the ability of the site to meet its conservation objectives, and has additionally examined the magnitude of impact, as apportioned to each relevant MPA, and whether this would represent an LSE (e.g. through examining whether mortality would be increased by >1%). We are of the view that this approach may not be appropriate for projects where larger magnitude impacts are expected. Table 1.68: Throughout the HRA, the qualifying features of Skomer, Skokholm and the Seas off Pembrokeshire/Sgomer, Sgogwm a Moroedd Penfro SPA appear to be incorrect. We recommend the features and assemblages are carefully checked against the SPA designation information (found here: https://jncc.gov.uk/our-work/skomer-skokholm-and-the-seas-off-pembrokeshire-mpa), and the details within the HRA updated. We have advised on errors in the description of features of Skomer, Skokholm and the Seas off Pembrokeshire/Sgomer, Sgogwm a Moroedd Penfro SPA during the Section 42 PEIR response, yet the errors remain. This comment also applies to the Volume 2, Chapter 5: Offshore ornithology, Table 5.10. Section 1.4.6.49: As far as we are able to calculate, we generate different values of apportioned adult impacts for at least great black-backed gull and kittiwake compared to those in the HRA Stage 1 Screening Report appendix tables. Due to the unclear method and values used, it is not known whether there are errors in the calculation, or a different method has been applied, or different values are being used, to those we assume are used. We recommend a thorough check of the values and calculations used to generate the results in the HRA Stage 1 Screening Report, and that the values and method of apportioning impacts are fully presented. Without these, we cannot confidently replicate the results, and hence we cannot have confidence in the results. HRA Stage 2 Information to Support an Appropriate Assessment Part Three: Special Protection Areas and Ramsar sites Assessments We disagree with several elements of the assessment to offshore ornithology within the HRA. In addition, there are multiple errors within the tables and text, and errors when using values in subsequent stages of the assessment. Many aspects of the assessment are difficult to follow what has been done or where values have come from. Due to these disagreements, errors, and lack of clarity, we do not have confidence in the results, nor are we able to agree with the overall conclusions of the HRA, particularly with regards to Skomer, Skokholm and the Seas off Pembrokeshire/Sgomer, Sgogwm a Moroedd Penfro SPA. Section 1.4.6.3: The threshold of using 0.05% baseline mortality from the project alone to screen whether impacts should be considered in-combination was not raised by the applicant during EWG meetings or subsequently, and therefore JNCC has not agreed to this approach. We recommend that the Applicant be clear on what this percent increase in baseline mortality would be in absolute mortality terms. We are not aware that similar thresholds have been applied in other cases to screen in or out from in-combination assessment, and note that the East Anglia Two OWF HRA does not refer to such a threshold when considering whether a project should be considered in-combination with other Plans and Projects (https://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010078/EN010078-010066-EA2-HabitatsRegulationsAssessment.pdf). We request that the Applicant provide justification for the appropriateness of this approach. Section 1.6.3.20: Note that predicted works (cable repair and reburial) would not need to occur concurrently in order to have the predicted impacts (just within the same non-breeding season). However, we welcome that the assessment is based on the total predicted habitat loss, irrespective of when it may occur. Section 1.6.3.44: We disagree with the interpretation that birds on migration are not specifically part of the Liverpool Bay/Bae Lerpwl SPA citation and therefore are not considered part of the non-breeding season assemblage. The SPA citation refers to non-breeding birds. There are no breeding red-throated divers in England or Wales, and therefore any birds present within the SPA will be non-breeding birds (even when present during the defined breeding season cited). We therefore do not agree that they can be discounted as not part of the protected population. We do note however that as per the SPA Conservation Advice, April and September represent months where smaller numbers of this species can be expected, and significant Impact and Adverse Effect on Integrity (AEOI) is less likely than in ‘core’ months of the non-breeding period. Marine mammal comments The following documents were reviewed in providing this response: Environmental Statement:  Volume 1, Chapter 5: Environmental impact assessment methodology  Volume 2, Chapter 4: Marine mammals  Volume 2, Chapter 11: Inter-related effects – Offshore  Volume 5, Annex 3.1: Underwater sound technical report  Volume 5, Annex 5.1: Cumulative effects screening matrix  Volume 6, Annex 4.1: Marine mammal technical report  Volume 8, Annex 2.2: Climate change risk assessment HRA:  Stage 1 Screening report  Stage 2 Information to support an Appropriate Assessment  Part 1, Introduction and background  Part 2, Special Areas of Conservation (SAC) assessments  HRA integrity matrices Offshore Plans:  Mitigation and monitoring schedule  Outline underwater sound management strategy  Outline offshore operations and maintenance plan  Measures to minimise disturbance to marine mammals and rafting birds from transiting vessels  Outline marine mammal mitigation protocol Overall comments JNCC previously provided comment on the Mona Offshore Wind Project Preliminary Environmental Information Report (OIA Reference OIA-09444, dated 1 June 2023). Our current review and subsequent comments have focussed on outstanding issues with particular attention given to the information to support HRA and proposed mitigation measures. We maintain our advice that unexploded ordnance (UXO) clearance is not included as a licensed activity in the DCO/marine licence (particularly high order clearance) due to the lack of information available and the over precaution that must be incorporated into the impact assessment at this stage. For example, Section 1.6.2.1 of the draft Sound Management Strategy states the likely maximum size of UXO to be encountered is 130kg Net Explosive Quantity (NEQ), however, it also states the size of device could range between 25kg and 907kg. Without further information on what size of devices will need to be cleared, and confirmation of what clearance method will be used, the impact assessment (and associated mitigation plans) must consider the worst-case scenario, i.e. all clearances will involve high order detonation of a 907kg device. This is contrary with the Government et al. Joint Position Statement (for which an update will be published this month), which states low noise methods of clearance should always be prioritised with high order clearance only to be used in exceptional circumstances. While noise abatement for piling (described as a secondary mitigation measure) is now referred to in the impact assessment and mitigation plans, in practice it is considered last in the mitigation hierarchy i.e. after measures built into the project design and the use of marine mammal observers/acoustic deterrents. We are aware that Defra will be publishing a noise policy paper soon (announced at the Marine Management Organisation, MMO, workshop, 13 March 2024) which will include the expectation from the MMO that all offshore wind pile driving activity in English waters to demonstrate that they have utilised best endeavours to deliver noise reductions through the use of primary and/or secondary noise mitigation methods in the first instance from January 2025. While the array area for this project no longer overlaps with English waters, we strongly recommend that noise abatement and/or the use of alternative hammers are considered as a key part of the noise mitigation plan, with the assumption that it will be used appose to it may/could be. Such an approach will also support future European Protected Species (EPS) licence applications if required (use of alternatives), which are usually applied for post-consent. General comments We highlight the following for information:  JNCC (in collaboration with the other SNCBs) will be reviewing the current Effective Deterrent Ranges (EDRs) this coming year and identify new ones for activities not currently included (e.g. Acoustic Deterrent Devices, ADDs). Once available, these should be used in future assessments.  JNCC will be publishing new mitigation guidance specifically for when clearing UXO within the next month. We advise that the most recent guidance is used to inform future UXO clearance licence application and subsequent marine mammal mitigation plans.  An addendum to the SNCB mitigation guidance for piling will be published in the next two months, to bring the 2010 guidance up to date and reflect the preference for noise abatement to be used to mitigate impacts from noise. HRA Stage 1 Screening report Table 1.6: This document states that the distance to the North Anglesey Marine SAC from the Mona Array Area is 22.58km, whereas in other documents it is stated as 23.67km. Please clarify and ensure consistency between documents. Section 1.4.5, Table 1.125 and Paragraph 1.6.1.5: JNCC agree with the conclusion of potential LSE on the North Anglesey Marine SAC due to underwater sound from piling, and UXO clearance. We advise LSE is unlikely for the other harbour porpoise sites due to their distance from the proposed project. HRA Stage 2 Information to support an Appropriate Assessment We defer to NRW-A regarding SACs in territorial waters e.g. for seals and bottlenose dolphins. We agree with the use of EDRs to assess disturbance within the harbour porpoise SACs and assess overlap in the context of published temporal-spatial thresholds. Table 1.78: We question why the Bristol Channel Approaches SAC has been included here, whilst the West Wales Marine SAC has not? Bristol Channel Approaches SAC lies 274.8km from the Array Area, whereas West Wales Marine SAC is considerably closer (95.4km). Table 1.84: We reiterate our advice that UXO clearance is not included in the DCO as a licensed activity. We do, however, agree with the hierarchy provided here with regard to clearance options, i.e. that low order will be considered before high order, as required in the Government et al. UXO position statement. Table 1.100: This presumes the worst-case scenario that all UXOs would require high order clearance and applies the maximum 26km EDR. Submitting a separate application for UXO clearance once it is known precisely what is required would enable this assessment to be more realistic and not be over precautionary. Outline underwater sound management strategy Overall, we agree in principle with the plan to develop an underwater noise strategy, and that it should identify all potential noise sources associated with the project with further detail provided in associated mitigation plans. We also agree the draft strategy could be finalised post-consent (following refinement of the project design and further surveys being undertaken), provided we are confident the information to be provided within the final strategy will demonstrate potential impacts to marine mammals from noisy activities can be adequately mitigated/managed. The information provided in the current draft is, however, incomplete. We note the following in the draft document provided:  Generally, the proposed layout is acceptable however we recommend that Section 1.6 (construction activities) includes some information on how the design envelope has changed, rather than only discussing it in Section 1.7.  Noise abatement for piling is considered a secondary mitigation measure however the implication is that in practice, it will be considered last in the mitigation hierarchy. The use of noise abatement should be given more serious consideration, and we encourage investigating the feasibility of using hammer types that will result in lower levels of noise such as the Menck system mentioned in paragraph 1.8.2.11.  We reiterate our advice that UXO clearance is not included as a licenced activity in the DCO/marine licence (particularly high order clearance) due to the lack of information available and the over precaution that must be incorporated into the impact assessment at this stage. For example, Section 1.6.2.1 of the strategy states the likely maximum size of UXO to be encountered is 130kg NEQ, however, it also states the size of device could range between 25kg and 907kg. Without further information on what size of devices will actually need to be cleared, and confirmation of what clearance method will be used, this strategy (and associated mitigation plans) must consider the worst-case scenario presented within the ES (907kg) and describe mitigation measures that will reduce those predicted impacts.  We do, however, agree to UXO clearance being included in this document at this stage as the strategy represents a holistic view of all noisy activities.  In line with the Governments Joint Position Statement (for which an update will be published this month), low noise methods of clearance should always be prioritised with high order clearance only to be used in exceptional circumstances.  JNCC do not recommend the use of scare charges prior to UXO clearance as a form of soft start (Section 1.5.4.3).  It is unclear why this document only appears to be focussing on two marine mammal species (bottlenose dolphin and harbour porpoise). Without mitigation, all marine mammals are sensitive to injury and disturbance from piling and UXO clearance; and as European Protected Species, all cetacean species are protected from both throughout their natural range. While some species may be more abundant in the development area, the current wording suggests (incorrectly) that only two species are at risk. Mitigation and monitoring schedule The purpose of this document is to demonstrate how the Mona Offshore Wind Project has considered mitigation and monitoring commitments regarding environmental impacts identified through the Environmental Impact Assessment. Table Ref 29-34: JNCC agrees with the commitment to develop and adhere to a Marine Mammal Mitigation Plan; see below for comments on the plan provided. Ref 35: The Underwater Sound Management Strategy (UWSMS) is J16 of the Marine Plan, and not J19 as stated here. Outline Offshore Operations and Maintenance Plan We encourage the developer to submit spatial and temporal information data on all licensed noisy activities to the Marine Noise Registry (MNR), including geophysical surveys which do not require a marine licence. This information will be added to other data provided for licensed activities therefore helping generate a more accurate picture of impulsive noise occurring in UK waters. The MNR is an online platform administered by JNCC for industry and regulators to enter activity information including location, date, and source property data. Outline marine mammal mitigation protocol In line with our previous advice that UXO clearance is not included as a licenced activity in the DCO/deemed marine licence, we do not recommend that a single mitigation plan is developed for this and piling. Instead, a separate Marine Mammal Mitigation Protocol (MMMP) should be developed to support any future licence application. To support this, we highlight that:  Defra will be publishing an update to the Government et al. UXO position paper in the next month. This strengthens the requirement to prioritise low noise methods of clearance and provides guidance on suitable evidence to support the use of such methods.  JNCC will be publishing new mitigation guidelines specifically for when clearing UXOs in the next month. These should be considered when designing mitigation plans for this activity.  JNCC do not advocate the use of scare charges as a soft start for UXO as their scaring effect is not proven (Lewis 1996, Keevin and Hempen 1997), and would result in unnecessary additional noise being emitted into the environment.  The mitigation zone should cover the full range of predicted injury and not be restricted to the 1km referred to in the 2010 guidelines. A minimum radius of 1km should be applied.  Two marine mammal observers should be used to reflect the size of the mitigation zone. If Passive Acoustic Monitoring (PAM) is to be used to supplement the visual searches, an additional team member will be required to monitor this (so three in total).  UXO clearance should not be undertaken at night or during periods of limited visibility. JNCC recently published guidance on the use of PAM as mitigation, which may be found here https://hub.jncc.gov.uk/assets/fb7d345b-ec24-4c60-aba2-894e50375e33. We recommend that this guidance is considered when finalising the piling MMMP. An update to McGarry et al. (2017) reviewing evidence to support the use of ADDs is being finalised and will be available soon and additional guidance for when using ADDs is currently being developed; refer to the JNCC webpage for updates. JNCC currently advise that a visual search is undertaken prior to activating ADDs and visual searches should be adapted to accommodate this. Paragraph 1.7.2.3 states that ‘PTS onset ranges will be further reduced by the application of ADDs’. This is incorrect. The Permanent Threshold Shift (PTS) onset range remains the same, the ADD is used to encourage animals to leave this area before the sound source is activated. Volume 6, Annex 4.1: Marine mammal technical report We previously requested that a qualitative review of survey coverage during baseline aerial surveys be provided to better understand the value of the survey data. For example, was coverage even and were key areas of the Mona array areas covered by the surveys? We note the proportion of the survey area analysed has increased from 12 to 15% however our previous comment remains valid. It would also be beneficial to understand how this increase have been achieved and what benefits are provided. Benthic ecology (offshore) The following documents were reviewed in providing this response: Environmental Statement:  Volume 1, Chapter 3: Project Description  Volume 1, Chapter 5: Environmental Impact Assessment Methodology  Volume 2, Chapter 1: Physical Processes  Volume 2, Chapter 2: Benthic subtidal and intertidal ecology  Volume 2, Chapter 11: Inter-related Effects – Offshore  Volume 5, Annex 5.1: Cumulative effects screening matrix  Volume 5, Annex 5.2: Transboundary impacts screening.  Volume 6, Annex 1.1: Physical Processes Technical Report  Volume 6, Annex 2.1: Benthic Subtidal and Intertidal Ecology Technical Report HRA:  Stage 1 Screening report  Stage 2 Information to support an Appropriate Assessment  Part 1, Introduction and background  HRA Integrity Matrices  Marine Conservation Zone Screening Report Offshore Plans:  Offshore In-Principle Monitoring Plan  Mona Array Area – Site Characterisation Report  Offshore Cable Corridor Site Characterisation Report The following advice relates to the offshore environment, extending out from the 12nm limit. For benthic ecology advice within 12nm, we defer to Natural Resources Wales (NRW). Overall comments JNCC are of the opinion that not all seabed impacts have been fully considered and it was not always clear that the correct footprint values have been utilised within the analysis or between chapters. Further detail of this is provided in the below sections. JNCC do not agree with the values attributed within the assessment of significant effects, covered in Sections 2.9 and 2.11 of Volume 2, Chapter 2. The magnitude of impact has been assessed too low, incorrect assumptions of feature sensitivity has been applied to the seapens and burrowing megafauna communities Important Ecological Features (IEF), and the subsequent adverse significance has been under-represented. As an example, taking the ‘as is’ situation with a ‘Low’ magnitude of impact and a ‘High’ sensitivity, the adverse significance would be ‘Minor or Moderate’, as detailed on page 17 of Volume 1, Chapter 5, but has been reported as ‘Minor’. We believe it would be more appropriate to take the worst-case scenario and apply a ‘Moderate’ adverse significance. We would therefore recommend that, as a minimum, all significance of effect be reassessed taking into account the worst-case scenario. In Section 5.3.6.8 and Table 5.4, of Volume 1 Chapter 5, the spatial extent of the impact is defined as "Geographical area over which the impact may occur". Including the whole licence area as the spatial extent is not proportionate to the identified impact pathway especially if the whole area has no opportunity to be impacted. This then gives an unrealistic percentage of impact area and subsequently a magnitude of impact that is not representative. Some more detailed examples are covered for specific sections below but we would recommend that all magnitude of impacts are re-assessed taking this into account. JNCC have concerns around the expected decommissioning of the infrastructure, in particular around the decommissioning of gravity-based infrastructure and the full removal of all cables. Lessons learnt from the oil and gas industry have shown that the decommissioning of gravity-based infrastructure is not always feasible, or possible, leading to permanent habitat change. The impacts of this scenario should be considered. JNCC welcomes the proposal to remove all cabling from the Array Area and Cable Corridor. Based on our current experience, this is not always possible, especially when the cable is buried. Leaving buried cables in situ and removing un-buried sections would normally include protection of the cut end with rock dump increasing the final footprint of the project. Although JNCC acknowledge future advancement of decommissioning technology may solve this issue, this scenario has not been considered. Volume 1, Chapter 3: Project Description Section 3.5.4.3, page 10: “If Mona infrastructure crosses any out of service cables, these will be removed where feasible.” It is not clear if any remediation (i.e. rock dump for protection) will be carried out on the cut ends of the out of service cables left on the seabed. Table 3.4, page 12: As the cable corridor includes both the inshore and offshore (outside 12nm) waters, it is not possible to determine the maximum design parameters for sandwave clearance in the offshore. We assume that the majority of sandwave clearance within this area will be inshore. Table 3.11 and 3.12, page 22, and Tables 3.14 to 3.17, pages 25 to 28: Values for the maximum seabed area (total foundations and scour protection for all foundations) were found to be incorrect in all six of the above listed tables. Assuming the values for the maximum seabed area per foundation and scour protection per foundation are correct, the total foundations and scour protection for all foundations values were found to be significantly underestimated (see table below). By our calculations, the following totals should be: Table 3.11: Original total = 284,360m2; corrected total* = 401,472m2; underestimated difference = 117,112m2 Table 3.12: Original total = 10,745m2 ; corrected total* = 35,336m2; underestimated difference = 24,591m2 Table 3.14: Original total = 735,488m2; corrected total* = 1,038,336m2; underestimated difference = 302,848m2 Table 3.15: Original total = 24,964m2 ; corrected total* = 60,116m2; underestimated difference = 35,152m2 Table 3.16: Original total = 612,084m2; corrected total* = 724,896m2; underestimated difference = 112,812m2 Table 3.17: Original total = 24,941m2 ; corrected total* = 74,508m2; underestimated difference = 49,567m2 * This is based on our interpretation of the data within the ES, notwithstanding our comments above on the numerous numerical errors throughout the ES. Section 3.5.8.7, page 23: Drill arisings from drilling of pin piles will create cuttings piles. A maximum seabed impact area should be calculated for these as cutting piles will impact the local environment and should be considered in more detail. Section 3.13.2.3, page 80: Wording in relation to cable decommissioning was found to be inconsistent between documents. This section suggests cables “may be retrieved” at decommissioning while Volume 2, Chapter 2, ‘Mona ES Benthic subtidal and intertidal ecology’ (Table 2.18, page 79) states all cables “will be removed” at decommissioning. JNCC assume all cables will be removed at decommissioning but this needs to be clarified by the applicant. Section 3.13.2.4, page 80: JNCC would expect all mattresses (concrete and frond) and rock bags used for cable protection to be removed at decommissioning. Section 3.13.2.5, page 81: We would agree that the cable installation and removal impacts would have the same temporary impact. However, if cables were left in situ and required protection through rock dump (for example through cut ends or free spans), this would increase the permanent impact to the seabed and should be considered further. Volume 2, Chapter 1: Physical Processes Section 1.9.5.10, page 83: We believe that the total Offshore Substation Platforms (OSP) footprint should be 20,180m2 and not 19,500m2 as detailed in comments above regarding the tables in Volume 1, Chapter 3. Note, the calculations detailed here are based on our interpretation of the data within the ES, notwithstanding our comments above on the numerous numerical errors throughout the ES. Volume 2, Chapter 2: Benthic subtidal and intertidal ecology Table 2.8, page 31: We agree that Jack up vessel events on their own would be a temporary habitat loss/disturbance. However, jack up events regularly require extra stabilisation through rock dumping, particularly in softer seabed environments and/or within high dynamic environments. The extra rock dump required for jack up events has not been accounted for and should be considered a permanent impact and be included within the long term habitat loss/habitat alteration impact during construction, operation and maintenance, and also during decommissioning. Foundation removal does not address gravity-based structures for turbines or OSPs. If these are not possible to decommission (see comments above), they should be treated as a permanent habitat change. Introduction of additional rock protection has not been considered. For example, at cable cut ends if not fully removed, at cable free spans, jack up vessel stabilisation (as discussed above), cable crossings and protection, or scour protection. Table 2.18, page 84: We welcome the suggested removal of all scour protection, cable protection, and crossing protection. However, the detail provided within this table contradicts details provided in Volume1, Chapter 3, Section 3.13.2.4, page 80 (see previous comment). Furthermore, if rock dump were to be used for protection, it is highly unlikely that the rock will be able to be removed and would therefore remain a permanent impact. Table 2.18, page 85: Changes in physical processes will occur at all three phases, not just the operation and maintenance phase. Decommissioning will affect physical processes, although at a much smaller scale, with the addition of rock dump and infrastructure that will be permanently left in situ. Section 2.9.2.27, page 103: We would not agree with a reduction in the sensitivity of the seapens and burrowing megafauna communities from ‘High’ to ‘Medium’. We acknowledge that seapens have not been recorded within the site-specific surveys to date but seapens do not have to be present to define this OSPAR T&D habitat, as also acknowledged within this section. For this reasoning, it would not be appropriate to reduce the sensitivity to ‘Medium’ and it should remain as ‘High’. This would also apply to all subsequent sections (e.g. Section 2.9.2.32). Section 2.9.2.51, page 110: We agree that the seabed will recover after the removal of the jack-up vessel’s spud cans but only when no rock dump has been used for stabilisation or scour protection of the spud cans (see comment on Table 2.8 above). Section 2.9.5.10, page 146: JNCC do not agree with a low magnitude of impact, considering over two million square meters (Section 2.9.5.7) of seabed will be permanently impacted/changed. Section 2.9.5.7 highlights the impact area and gives a percentage of that compared with the Mona benthic subtidal and intertidal ecology study area (0.17%). This is not helpful as those areas include large portions that will not be directly impacted by the operations. A more useful area comparison for calculating the impact percentage would be of the total direct and indirect (temporary) impact areas. Combining the Long-term habitat loss and Temporary habitat loss areas would provide a more meaningful impact percentage and subsequent meaningful magnitude. Section 2.9.5.22, page 150: JNCC do not agree with the suggestion that the permanent presence of cable and scour protection should be considered as permanent habitat alteration rather than permanent habitat loss. The permanent introduction of hard substrates into a soft sediment environment would be a permanent habitat loss that leads to a regime shift of that habitat (i.e. a permanent habitat alteration). It should therefore be considered as permanent habitat loss. This should be taken into account when re-assessing the magnitude of impact (Section 2.9.5.23, page 151). Section 2.9.6.6, page 153: JNCC recognise that settlement and subsequent recruitment on clean artificial structures is very complex. It should not be expected that colonisation will consist entirely of already present flora and fauna. Opportunistic colonisation will occur from flora and fauna that would not normally be recorded in the area due to the clean artificial surfaces allowing for opportunistic settlement. This has the potential to alter subsequent settlement and recruitment that can lead to a different final community composition. Additionally, temporal variation will also determine the final community composition (e.g. studies have shown different community composition depending on the time of year when the artificial structure was introduced). Please contact JNCC with any questions regarding the above comments.”