The Western Platform Multi Client 3D Seismic Survey Marine Mammal
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The Western Platform Multi Client 3D Seismic Survey Marine Mammal Impact Assessment Report Number 740.10032-R02 23 November 2017 Schlumberger New Zealand Ltd 94 Paraite Road New Plymouth 4373 Version: v1.0 Schlumberger New Zealand Ltd Report Number 740.10032-R02 The Western Platform Multi Client 3D Seismic Survey 23 November 2017 Marine Mammal Impact Assessment v1.0 Page 2 The Western Platform Multi Client 3D Seismic Survey Marine Mammal Impact Assessment PREPARED BY: SLR Consulting NZ Limited Company Number 2443058 5 Duncan Street Port Nelson 7010, Nelson New Zealand (PO Box 5061, Port Nelson 7043 Nelson New Zealand) +64 274 898 628 [email protected] www.slrconsulting.com This report has been prepared by SLR Consulting NZ Limited with all reasonable skill, care and diligence, and taking account of the timescale and resources allocated to it by agreement with 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 Schlumberger New Zealand Ltd. 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 740.10032-R02-v1.0 23 November 2017 740.10032-R02 -v0.2 14 November 2017 740.10032-R01-v0.1 25 October 2017 SLR Consulting NZ Limited Schlumberger New Zealand Ltd Report Number 740.10032-R02 The Western Platform Multi Client 3D Seismic Survey 23 November 2017 Marine Mammal Impact Assessment v1.0 Page 3 Executive Summary Schlumberger New Zealand Ltd (Schlumberger) is proposing to acquire a three dimensional (3D) multi- client marine seismic survey in the Taranaki Basin. The ‘Western Platform Multi-Client 3D Seismic Survey’ is located off the west coast of central and southern North Island. The seismic survey is predicted to occur between December 2017 and March 2018 with an acoustic source volume of 5,085 in3. Under the Exclusive Economic Zone (Environmental Effects) Permitted Activities Regulations 2013, seismic operations in New Zealand’s Exclusive Economic Zone (EEZ) must comply with the Department of Conservation’s (DOC) 2013 Code of Conduct for Minimising Acoustic Disturbance to Marine Mammals from Seismic Survey Operations (the ‘Code of Conduct’). The preparation of a Marine Mammal Impact Assessment (MMIA) is a requirement of the Code of Conduct in order to describe the proposed seismic operations, provide a description of the baseline environment, identify potential effects of the operations on the environment, and to specify any proposed mitigation measures. An Environmental Risk Assessment (ERA) process is utilised throughout this MMIA to assess the significance of any predicted effects on the biological, socio-economic and cultural environments of relevance to the Operational Area. Engagement with stakeholders was also undertaken by Schlumberger as a key part of the development of this MMIA. Evaluations of the baseline environment of the Operational Area indicate that minke whales, bottlenose dolphins, dusky dolphins, false killer whales, killer whales, Gray’s beaked whales, long-finned pilot whales, pygmy blue whales, sperm whales, pygmy sperm whales, common dolphins and New Zealand fur seals are the marine mammal species most likely to be present. It is well recognised that acoustic disturbance from seismic surveys has the potential to impact marine mammals. The Code of Conduct was developed by DOC in order to address both behavioural and physiological effects associated with acoustic disturbance. Compliance with the Code of Conduct is the primary mitigation measure that will be employed during the Western Platform Multi-Client 3D Seismic Survey. The following specific actions are particularly important with regards to implementing the Code of Conduct: Marine Mammal Observers (MMO) will be present on the seismic survey vessel to detect marine mammals using both visual and acoustic techniques; Seismic operations will be delayed if marine mammals are detected in close proximity to the acoustic source when starting up; The power of the acoustic source will be gradually increased during a ‘soft start’ prior to any operations to ensure that any undetected marine mammals have an opportunity to leave the vicinity before full operational power is reached; and The acoustic source will be shut down if marine mammals enter the defined mitigation zones. Sound transmission loss modelling predicts how far sound emitted from the seismic survey is predicted to travel underwater, and is used to assess the validity of the mitigation zones specified in the Code of Conduct. The modelling results did not comply with the Sound Exposure Level thresholds for the standard mitigation zones at 1 km for parts of the Western Platform Multi-Client 3D Seismic Survey; hence, a larger mitigation zone has been proposed for this particular survey to ensure compliance levels are met. In particular, a mitigation zone of 1.5 km will be adopted for all ‘Species of Concern’ (with or without calves) throughout the Operational Area. In addition to compliance with the Code of Conduct, Schlumberger have committed to the following actions to avoid, remedy or mitigate potential adverse effects on ecological, socio-economic and cultural components of the environment during the Western Platform Multi-Client 3D Seismic Survey: SLR Consulting NZ Limited Schlumberger New Zealand Ltd Report Number 740.10032-R02 The Western Platform Multi Client 3D Seismic Survey 23 November 2017 Marine Mammal Impact Assessment v1.0 Page 4 Executive Summary Schlumberger has undertaken source modelling to ensure that their survey is using the lowest possible acoustic source volume while still ensuring the geological objectives of the survey can be fulfilled; Seismic operations will continue around the clock (as possible) to reduce the overall duration of the survey; Marine mammal sightings will be collected whilst off-survey (e.g. during transit to and from the Operational Area to the local port etc.); MMOs will be vigilant for entanglement incidents and will report any dead marine mammals observed at sea; MMOs to notify DOC immediately of any Hector’s/Maui’s dolphin sightings; Weekly MMO reports to be provided to the regulators; Schlumberger will consider covering the cost of necropsies on a case-by-case basis in the event of marine mammal strandings; Schlumberger will operate in accordance with industry best practice, including compliance with international conventions relating to waste disposal, atmospheric emissions, oil pollution and biosecurity; Iwi Marine Mammal Operators (MMOs) and Passive Acoustic Monitoring (PAM) operators will be provided with employment opportunities during the survey; The seismic vessel will receive an iwi blessing before the survey commences; Iwi will be updated on any non-compliance issues that may arise during the survey; Post-survey engagement to be conducted to inform iwi and stakeholders of key survey outcomes; and Post-survey bathymetry information will be offered to stakeholder groups. This MMIA identifies all potential environmental effects from the Western Platform Multi-Client 3D Seismic Survey and describes the mitigation measures that will be implemented to ensure that any potential effects are reduced to levels as low as reasonably practicable. Although the MMIA focusses on marine mammal impacts, potential effects on other components of the marine ecosystem and existing maritime activities are also considered. In summary, the predicted effects of the Western Platform Multi-Client 3D Seismic Survey are generally considered to be low to medium, with medium effects representing a small environmental impact that is sufficiently managed by the mitigation measures that have been proposed. There is however a high risk of auditory masking of marine mammals (particularly blue whales in South Taranaki Bight); however the long acquisition lines will provide a period of relative relief from masking every 24 hours. SLR Consulting NZ Limited Schlumberger New Zealand Ltd Report Number 740.10032-R02 The Western Platform Multi Client 3D Seismic Survey 23 November 2017 Marine Mammal Impact Assessment v1.0 Page 5 1 INTRODUCTION 9 1.1 Background 9 1.2 General Approach 9 2 PROJECT DESCRIPTION 11 2.1 Marine Seismic Surveys - overview 11 2.1.1 2D and 3D surveys 11 2.1.2 Underwater sound 11 2.1.3 The acoustic source 12 2.1.4 The streamers 13 2.2 Western Platform Multi-Client 3D Seismic Survey 13 2.3 Navigational Safety 16 2.4 Survey design considerations 16 3 LEGISLATIVE FRAMEWORK 19 3.1 Crown Minerals Act 1991 19 3.2 Resource Management Act 1991 19 3.3 Marine Mammals Protection Act 1978 20 3.4 Exclusive Economic Zone & Continental Shelf (Environmental Effects) Act 2012 20 3.5 2013 Code of Conduct 21 3.5.1 Notification 21 3.5.2 Marine Mammal Impact Assessment 21 3.5.3 Areas of Ecological Importance 22 3.5.4 Observer Requirements 24 3.5.5 Operational and Reporting Requirements 25 3.5.6 Pre-start Observations 25 3.5.7 Soft Starts 26 3.5.8 Delayed Starts and Shutdowns 27 4 ENGAGEMENT 28 5 DESCRIPTION OF THE OPERATIONAL AREA 29 5.1 Physical Environment 29 5.1.1 Meteorology 29 5.1.2 Currents and Waves 29 5.1.3 Thermoclines and Sea Surface Temperature 32 5.1.4 Bathymetry and Geology 32 5.2 Biological Environment 35