GREAT SOUTH BASIN CHECKSHOT SURVEY Marine Mammal Impact Assessment Prepared for: OMV GSB Limited Level 20, The Majestic Centre 100 Willis Street PO Box 2621 Wellington 6015 New Zealand SLR Ref: 740.10083.00300-R01 Version No: -v1.0 December 2019 OMV GSB Limited SLR Ref No: 740.10083.00300-R01-v2.0 OMV GSB Checkshot Survey Great South Basin Checkshot Survey MMIA 20191220.docx Marine Mammal Impact Assessment December 2019 PREPARED BY SLR Consulting NZ Limited Company Number 2443058 6/A Cambridge Street Richmond, Nelson 7020 New Zealand (PO Box 3032, Richmond 7050 New Zealand) T: +64 274 898 628 E: [email protected] www.slrconsulting.com BASIS OF REPORT This report has been prepared by SLR Consulting NZ Limited (SLR) with all reasonable skill, care and diligence, and taking account of the timescale and resources allocated to it by agreement with OMV GSB Limited (the Client). Information reported herein is based on the interpretation of data collected, which has been accepted in good faith as being accurate and valid. This report is for the exclusive use of the Client. No warranties or guarantees are expressed or should be inferred by any third parties. This report may not be relied upon by other parties without written consent from SLR. SLR disclaims any responsibility to the Client and others in respect of any matters outside the agreed scope of the work. DOCUMENT CONTROL Reference Date Prepared Checked Authorised 740.10083.00300-R01-v2.0 20 December 2019 SLR Consulting NZ Limited 740.10083.00300-R01-v1.0 10 December 2019 SLR Consulting NZ Limited Page 2 OMV GSB Limited SLR Ref No: 740.10083.00300-R01-v2.0 OMV GSB Checkshot Survey Great South Basin Checkshot Survey MMIA 20191220.docx Marine Mammal Impact Assessment December 2019 EXECUTIVE SUMMARY OMV GSB Limited (OMV) will be undertaking a multi-well Exploration and Appraisal Drilling (EAD) Programme within the Great South Basin (GSB); hereafter referred to as the GSB EAD Programme. The GSB EAD Programme is expected to commence in Q1 2020 with the drilling of the Tāwhaki-1 well. Drilling activities associated with the GSB EAD Programme will be undertaken within OMV’s Petroleum Exploration Permit (PEP) 50119. A checkshot survey, which is a form of borehole seismic survey used to identify specific characteristics about geological features below the seafloor that have been intersected during drilling activities, may be undertaken in the event that hydrocarbon accumulations are discovered during the GSB EAD Programme (GSB Checkshot Survey). In the event that no hydrocarbon accumulations are discovered, no checkshot survey is likely to be required; however, that will not be known until the well has been drilled and appropriate formation evaluation has been undertaken. The objective of the GSB Checkshot Survey is to ascertain further information about the velocity characteristics of the strata penetrated by the wellbore, in order to accurately translate between sonic/density properties measured within the well and acoustic data from seismic surveys recorded in the vicinity of the well. Under the Exclusive Economic Zone and Continental Shelf (Environmental Effects - Permitted Activities) Regulations (Permitted Activities Regulations), seismic operations in New Zealand’s Exclusive Economic Zone (EEZ) must comply with the Department of Conservation’s (DOC) 2013 Code for Conduct for Minimising Acoustic Disturbance to Marine Mammals from Seismic Survey Operations (Code of Conduct). Under the Code of Conduct, a Marine Mammal Impact Assessment (MMIA) is required in order to describe the proposed seismic operations, provide a description of the baseline environment, identify any potential environmental effects from the seismic operations, and to specify any proposed mitigation measures to minimise environmental effects. An Operational Area has been drawn around the Tāwhaki-1 well location in order to describe the marine environment and potential effects of the GSB Checkshot Survey. Supplementary MMIAs will be submitted if additional wells are required in the GSB EAD Programme, specific to the characteristics of those locations. Where seismic activities are undertaken within an Area of Ecological Importance, Sound Transmission Loss Modelling (STLM) is also required; although the Operational Area for the GSB Checkshot Survey does not occur within an Area of Ecological Importance, STLM has been carried out to ensure the standard mitigation zones will provide adequate protection to marine mammals. An Environmental Risk Assessment (ERA) process has been utilised within this MMIA to assess the significance of any predicted adverse effects on biological, socio- economic, and cultural environments of relevance to the Operational Area. Stakeholder engagement has been carried out by OMV as a key part of the GSB Checkshot Survey and wider GSB EAD Programme. Utilising data within DOC’s stranding and sighting database, and knowledge of migration paths and habitat preferences of each species (obtained from published scientific literature), the following marine mammals are likely to be present within the Operational Area: bottlenose dolphin, dusky dolphin, false killer whale, Gray’s beaked whale, killer whale, long-finned pilot whale, New Zealand sea lion, New Zealand fur seal, southern elephant seal, southern right whale, southern right whale dolphin, sperm whale, Shepherd’s beaked whale and strap-toothed whale. Andrew’s beaked whale, Antarctic minke whale, common dolphin, Cuvier’s beaked whale, dwarf minke whale, Hector’s beaked whale, Hector’s dolphin, pygmy sperm whale, southern bottlenose whale, and spectacled porpoise are considered to have a possible presence within the Operational Area. Page 3 OMV GSB Limited SLR Ref No: 740.10083.00300-R01-v2.0 OMV GSB Checkshot Survey Great South Basin Checkshot Survey MMIA 20191220.docx Marine Mammal Impact Assessment December 2019 EXECUTIVE SUMMARY OMV’s proposed checkshot survey falls within the classification of a Level 1 marine seismic survey under the Code of Conduct due to the proposed source volume (i.e. > 427 in3). Compliance with the Code of Conduct for a Level 1 marine seismic survey is the primary mitigation measure that OMV will employ during the GSB Checkshot Survey. The full protocol of operational procedures and control measures that will be followed during the GSB Checkshot Survey are detailed in the Marine Mammal Mitigation Plan (MMMP, Appendix D) which will be used as a working document during the checkshot survey. The following specific actions are particularly important with regard to operating in accordance with the Code of Conduct: • Where available, two qualified Marine Mammal Observers (MMO) and two qualified Passive Acoustic Monitoring (PAM) Observers will be present for the duration of the GSB Checkshot Survey. In the event that two qualified MMOs or PAM Operators are unable to be engaged, the Code of Conduct provides for a qualified observer to act in a supervisor/mentor role to a trained observer; • The MMOs will be present onboard the mobile offshore drilling unit (MODU) and the PAM Operators will be present onboard a support vessel to visually and acoustically detect for the presence of any marine mammals prior to the commencement of the checkshot surveys and for the duration of the survey. Due to the noise interference from the actively-operating MODU, PAM (Appendix B) will be deployed from the support vessel, which will circle the MODU within a radius of approximately 1 km; • Seismic operations will be delayed if marine mammals are detected within the mitigation zones as defined in the Code of Conduct; • The power of the acoustic source will be gradually increased through a ‘soft start’ procedure prior to any seismic operations commencing to ensure any undetected marine mammals have an opportunity to leave the mitigation zones before full operational power is reached; and • The acoustic source will be shut down if a marine mammal enters the relevant defined mitigation zones. STLM (Appendix A) has been used to verify the thresholds for the standard mitigation zones specified within the Code of Conduct. The short-range modelling prediction demonstrates that the maximum received Sound Exposure Level (SEL) will comply with the limits of 186 dB re 1µPa2·s at 200 m, and 171 dB re 1µPa2·s at 1.0 km and 1.5 km. While the focus of this MMIA is on marine mammals, potential effects on other environmental and socio- economic receptors have also been considered. Overall, the predicted effects of the GSB Checkshot Survey are considered to be sufficiently managed by the proposed mitigation measures, predominantly compliance with the Code of Conduct. Due to the small volume acoustic source that will be utilised during each survey, the potential for temporary threshold shift (TTS) to affect marine mammals will be restricted to within 123.5 m of the acoustic source, as demonstrated by STLM. The STLM results have confirmed that the proposed GSB Checkshot Survey is compliant with the requirements stipulated for SEL thresholds within the Code of Conduct. Page 4 OMV GSB Limited SLR Ref No: 740.10083.00300-R01-v2.0 OMV GSB Checkshot Survey Great South Basin Checkshot Survey MMIA 20191220.docx Marine Mammal Impact Assessment December 2019 CONTENTS 1 INTRODUCTION ......................................................................................................... 10 2 PROJECT DESCRIPTION .............................................................................................. 13 2.1 Marine Seismic Surveys – Overview ..........................................................................