Māui 4D Seismic Survey Marine Mammal Impact Assessment Report Number 740.10033-R01 11 January 2018 Shell Taranaki Limited 167 Devon Street West New Plymouth Version: v1.0 Shell Taranaki Limited Report Number 740.10033-R01 Māui 4D Seismic Survey 11 January 2018 Marine Mammal Impact Assessment Version v1.0 Page 2 Māui 4D 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 Shell Taranaki Limited. 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 740.10033-R01-v1.0 11 January 2018 Helen McConnell and Dan Govier Dan Govier Nicole Pannell 740.10033-R01-v0.2 31 December 2017 Helen McConnell and Dan Govier Dan Govier Nicole Pannell 740.10033-R01-v0.1 8 December 2017 Helen McConnell and Dan Govier Dan Govier Nicole Pannell SLR Consulting NZ Limited Shell Taranaki Limited Report Number 740.10033-R01 Māui 4D Seismic Survey 11 January 2018 Marine Mammal Impact Assessment Version v1.0 Page 3 Executive Summary Shell Taranaki Limited proposes to undertake a marine seismic survey, the ‘Māui 4D Seismic Survey’, in the Taranaki Basin. The objective of this survey is to monitor changes in the Māui Field hydrocarbon reservoir since the last seismic survey in 2002. Seismic operations are predicted to take place over a period of approximately 40 days; with the start of the survey planned for February 2018. The Operational Area for this survey is located off Cape Egmont and in waters to the southwest. Seismic operations will not occur in any waters within 21 km of shore, and the majority of operations will occur in water depths greater than 100 m. No seismic operations will occur within 6.5 km of the boundary to the West Coast North Island Marine Mammal Sanctuary. The nearest major settlement to the Operational Area is the coastal city of New Plymouth, located approximately 55 km to the northeast. The seismic survey would be undertaken using a specialised 3D seismic survey vessel, the MV Amazon Warrior, which will tow eight streamers, each measuring 3 km in length separated by 100 m spacings. The acoustic source of the proposed survey will also be towed by the MV Amazon Warrior and will consist of two 3,147 in3 arrays at a water depth of 6 m, which will be activated alternatively at an operating pressure of 2,000 psi. The acoustic sources are typically set off so that the shot-point interval is 18.75 m apart, and with an average vessel speed of 4.5 knots, this equates to activation every eight seconds. One support vessel and one chase vessel will accompany the MV Amazon Warrior to provide supplies, scout the area ahead for obstructions and to ensure other vessels are aware of the presence and extent of the streamers behind the seismic vessel. The Department of Conservation’s 2013 Code of Conduct for Minimising Acoustic Disturbance to Marine Mammals from Seismic Survey Operations (the ‘Code of Conduct’) defines three levels of marine seismic surveys based on acoustic source capacity. Based on this classification, the Māui 4D Seismic Survey is considered a ‘Level 1’ seismic survey and requires a Marine Mammal Impact Assessment (MMIA) to be assessed as sufficient to meet the requirements of the Code of Conduct by the Department of Conservation (DOC) before the survey commences. An important part of the MMIA development is consultation with interested parties and technical experts, and in preparation for the Māui 4D Seismic Survey, Shell Taranaki Limited is undertaking consultation with a wide range of stakeholders whose concerns will be taken into account. In assessing the potential impacts of the seismic survey on marine mammals the following steps were undertaken: all potential environmental sensitivities which could be vulnerable to seismic operations were identified; all potential environmental effects of the seismic operations were identified; mitigation actions were developed to avoid, remedy or mitigate each potential effect; and an assessment of the significance of each potential effect (based on likelihood, magnitude, geographical scale, and mitigation actions) was conducted. A thorough understanding of the existing environmental sensitivities in the offshore Taranaki region provides a fundamental basis for this MMIA. Environmental sensitivities include marine mammals, seabirds, fish species, benthic marine fauna and plankton. The MMIA process has identified that up to thirteen species of marine mammal could be present in the Operational Area; of these species only two, killer whales (Nationally Critical) and bottlenose dolphins (Nationally Endangered) are considered to be threatened under the New Zealand Threat Classification System. SLR Consulting NZ Limited Shell Taranaki Limited Report Number 740.10033-R01 Māui 4D Seismic Survey 11 January 2018 Marine Mammal Impact Assessment Version v1.0 Page 4 Executive Summary Other species of marine mammals could also be utilising habitat in the vicinity, including a number of ‘Species of Concern’ as defined by the Code of Conduct. Pygmy blue whales in particular use the South Taranaki Bight for foraging and recent evidence suggests that this area may also support a nursery ground for this species. Numerous seabird species are likely to be present in the Operational Area; however, Antipodean albatross, back-billed gull, fairy tern, Gibson’s albatross, Salvin’s mollymawk, black-fronted tern, black petrel, caspian tern, flesh-footed shearwater, grey-headed albatross, pied shag, red-billed gull, and Hutton’s shearwater have a DOC threat listing of nationally vulnerable or greater so are of greatest significance. The most commonly caught commercial fish species in this area are jack mackerel and barracouta, accounting for about 95% of the total catch in offshore Taranaki waters. As part of this MMIA, a range of potential effects on the environment have been assessed. To address these potential effects Shell Taranaki Limited will implement mitigation measures which aim to eliminate or minimise any negative environmental consequences as far as practicable. The introduction of sound into the marine environment is considered to be the most significant potential effect from the Māui 4D Seismic Survey. The primary mitigation tool to address these effects is compliance with the Code of Conduct which Shell Taranaki Limited commits to do for the duration of the survey, both in the EEZ and in the territorial sea. The Code of Conduct is highly regarded internationally, and is often cited as one of the most comprehensive management regimes in the world with regard to mitigating the effects of seismic operations on marine mammals (e.g. Wright & Cosentino, 2015). In accordance with the Code of Conduct, the measures that will be employed include: The use of pre-start observations by Marine Mammal Observers (MMOs) and Passive Acoustic Monitoring (PAM) to detect marine mammals (both visually and acoustically) prior to the commencement of seismic operations; The delay of operations in the event that marine mammals are detected; The use of ‘soft starts’ whereby the acoustic source volume is gradually increased over 20–40 minutes at the start of the survey to give any marine mammals the opportunity to leave the survey area before full power is reached; and The shutdown of the acoustic source if ‘Species of Concern’ are detected. Sound transmission loss modelling was conducted as part of this MMIA whereby acoustic propagation is modelled to predict the received sound levels at various underwater distances from the acoustic source. This modelling indicated that the proposed acoustic source was compliant with the standard mitigation zones and associated thresholds defined in the Code of Conduct. Hence no tailored mitigation zones are required during the Māui 4D Seismic Survey. In addition to full compliance with the Code of Conduct, Shell Taranaki Limited commits to the following management actions over and above those required: Whilst transiting to and from the Operational Area, and during daylight hours and good sighting conditions, a MMO will be on watch and recording marine mammal sightings; Weekly MMO reports will be provided to DOC and the Environmental Protection Authority (EPA); DOC will be notified immediately of any sightings of Māui or Hector’s dolphins; and SLR Consulting NZ Limited Shell Taranaki Limited Report Number 740.10033-R01 Māui 4D Seismic Survey 11 January 2018 Marine Mammal Impact Assessment Version v1.0 Page 5 Executive Summary If any stranding’s occur that result in mortality during the Māui 4D Seismic Survey or within 14 days of the survey completion date, Shell Taranaki Limited will, on a case-by-case basis, consider covering the costs of undertaking a necropsy in an attempt to determine the cause of death. Other potential environmental effects (outside those directly relating to marine mammals and noise) are addressed by adherence to the International Convention for the Prevention of Pollution from Ships 1978 (MARPOL), and the International Regulations for the Prevention of Collisions at Sea 1972 (COLREGS). In summary, the environmental effects associated with the Māui 4D Seismic Survey, when assessed in light of the proposed mitigation measures, are considered to be mostly minor or moderate whereby recovery is predicted within 24 hours.