Before the EPA Trans-Tasman Resources Ltd Ironsands Extraction Project

In the matter of the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012

And

In the matter of a board appointed to consider a marine consent application made by Trans-Tasman Resources Ltd to undertake iron ore extraction and processing operations offshore in the South Taranaki Bight

Executive Summary of Evidence of Dr Tara Anderson on behalf of Trans-Tasman Resources Ltd

29 March 2014

Introduction

1. My name is Tara Julie Anderson. I am a Scientist in Marine Ecology at the Nelson campus of the National Institute of Water and Atmospheric Research (NIWA), where I have been employed since March 2013. Prior to that I have been employed as a Scientist in Australia and the United States.

2. TTR’s proposal to extract seabed sediments and then redeposit de-orded sediment within the proposed mining area has direct implications for benthic assemblages within this area, while suspended sediments released into the water column have potential implications for benthic organisms within the broader region.

3. As an expert witness in marine benthic ecology I present evidence to the Decision-making Committee on the findings of two benthic ecology studies: The first, covering the mining and adjacent non-mining areas within the broader Patea Shoals region (an area of approximately 50 x 35 km in size) in water depths of 16-97 m, and the second, along the nearshore region of the South Taranaki Bight (approximately 35 km alongshore) between Hawera and Foxton in water depths of 3-32 m. These studies provide baseline characterisations of the types of benthic habitats and assemblages surveyed within these two regions. The findings of these studies provide a significantly increased understanding of the benthos of the South Taranaki Bight, particularly knowledge of benthic habitat types, their distribution and the associated communities of infauna and epifauna. Discussion of the potential effects of TTR’s proposed activities on the benthos is to be addressed in the evidence of Dr Dan McClary.

Key Conclusions - Patea Shoals Region:

4. Seven habitat types were recorded within the Broader Patea shoals region. Inshore of the 12 nm limit (depths < ~20 m) the inshelf zone comprised dynamic sand waves, rippled sands, wormfields, and small, patchy, low-relief rock outcrops. Beyond the 12 nm limit, the midshelf zone – within which the TTR mining area occurs –comprised two habitat types. Rippled sands occur in the shallower depths of the mining area (in depths <30 m) and extensively across the south mid-shelf. These areas were characterized by coarse grained sands with some gravels (mean grain size of 500.8 um, and a range of 300-781 um). Conversely, wormfields occurred in the deeper depths of the mining area (depths >30 m) and across the northern midshelf zone, and were characterized by much finer grained sands (mean grain size of 248.5, and a range of approx. 182-331 um).

5. Rippled sands in both mining and non-mining sites supported low epifaunal and infaunal abundance and diversity typical of highly disturbed environments, and did not differ significantly from those assemblages found in dynamic sand wave habitats inshore or Tucetona beds offshore.

6. Wormfields were significantly different from all other habitats, and supported intermediate numbers of epifauna and significantly higher numbers of infauna - driven by high albeit patchy numbers of the Sabellid tube worm Euchone sp A., along with a few characteristic but much lower density (i.e. Aricidea nd [motile worms], Cyclaspis sp, [cumacean crustacea], and three species of amphipod – shrimp-like crustaceans (Lysianassoidea and Photidae and Phoxocephalidae sp1).

7. Mining sites did not differ significantly from non-mining sites with similar depths and sediment characteristics. This was because both wormfield and rippled sand habitats were common across the midshelf region, albeit distributed inversely alongshore.

8. The majority of key epifauna and infauna were more abundant in non-mining sites, or were absent from mining sites. Only the Sabellid worm, Euchone sp A - that characterised the wormfields - was significantly more abundant in mining sites. Although, Euchone sp A were also abundant in non-mining sites north of the mining area.

9. Other than higher abundances of this worm there was no evidence within any of the datasets to suggest that the mining area is “unique” with respect to sediment characteristics or benthic organisms.

10. Beyond depths of around 45-50 m the shelf steepens. Here three habitats were recorded. Along the upper edge, rippled sands with live Tucetona but no shell rubble were apparent. Below this, two low-relief biogenic habitats - bivalve rubble down to 60 m and bryozoan rubble in depths > 60 m - supported the highest numbers and diversity of epibenthic assemblage, dominated by suspension feeders (700 ± 150 specimens compared with less than 200 ± 5 specimens in all other habitats, and 50 ± 5 species compared with less than 20 ± 2 species, Refer to Figure 18 – Patea Shoals report).

11. The shallower bivalve rubble, were characterised by earlier-staged colonisers, such as encrusting coralline paint and encrusting invertebrates (e.g. sponges); while the deeper bryozoan rubble supported later-stage colonisers, such as branching and foliose bryozoans, erect sponges and epiphytic bivalves. Of the 161 bryozoan species collected during the entire survey, 140 of these species were collected from the bryozoan rubble habitat.

12. Although diverse, the bryozoan community was not in a pristine state, rather communities were patchy with bryozoans mostly broken or part of the rubble making up this habitat. Dr Alison MacDiarmid has identified that areas along the 50m bathymetric contour where this bryozoan rubble habitat occurs are subject to intermittent bottom trawling (Benthic Ecology Joint statement Part 2).

13. Although rock outcrops were present inshore and supported diverse epibenthic assemblages characterised by mostly turfing red algae, bryozoans and sponges, these outcrops supported significantly fewer organisms and species than biogenic habitats offshore - likely due to the very small amount (<4%) of rocky outcrop available inshore.

14. Although large canopy-forming kelps (such as Ecklonia radiata) and many brown seaweeds are likely to be susceptible to small increases in suspended sediment concentrations, very few brown seaweed were collected or seen. The only species recorded commonly was Zonaria turneriana a short robust seaweed that grows on rock and sand, and can cope with periods of sediment burial. Similarly, the turf-forming, filamentous and branching red species that comprised the majority of macroalgae seen and collected on these outcrops, have sediment-trapping morphologies that enable them to dominate space under high depositional conditions.

15. Macroalgal assemblages growing on rock outcrops along the nearshore are already exposed to high background levels of turbidity and suspended sediments and consequently support species that can tolerate these conditions. The sediment veneer covering sections of these outcrops, along with the presence of detached macroalgae and invertebrates in adjacent soft sediment habitats indicate that these small low-lying outcrops likely undergo ongoing physical disturbance from water movement, sand scouring and sediment inundation. Based on Hadfield’s models of suspended sediments across this region these macroalgal assemblages are unlikely to change in response to mining activities. Although I address this further in my response to issues raised below.

16. Further offshore, several deep-water red macroalgal species were seen and collected within the bivalve-rubble habitat in depths of 45-60 m. Species consisted of encrusting coralline paint growing on the remnant Tucetona shells (0-30% cover on shells), and very small-sized branching or foliose red algae (3 species were collected, but these generally accounted for < 0-2% of still images). Although these algal groups are found in deep-water/low-light conditions, very little is known about algal species occurring in depths >30 m, as until recently very few intensive sampling studies were carried out in these deep offshore environments. Consequently little is known about how these species might respond to changing environmental conditions.

17. In contrast to inshore and offshore zones, the midshelf (or 20-40 m) supported almost no macroalgae within either the mining area or adjacent non-mining sites.

18. Iron concentrations were positively correlated with the occurrence of very fine sands (63-125 um), but did not appear to play a significant role in structuring marine benthic communities within the Patea Shoals region.

19. Very few studies, especially of this spatial intensity, have been undertaken on the exposed continental shelf of New Zealand’s west coast. Some new species were recorded during this survey along with northern or southern extensions of previously known species distributions, but these findings may to some extent simply reflect the lack of study in this high-energy environment.

20. To reiterate, discussion of the potential effects of TTR’s proposed activities on the benthos will be addressed by Dr Dan McClary.

Key Conclusions - Nearshore Region:

21. Along the nearshore region of the STB, 92% of the seabed consisted of soft sediments while rock outcrops accounted for 8% of the seabed.

22. Three types of soft-sediment habitats were recorded. In the north and central areas, the seabed is characterised by “well-sorted fine sands in dynamic rippled bedforms”, while further south past Whanganui the seabed is “flat or subtly rippled with higher proportions of mud”, further offshore in depths >20 m the seabed was characterised by “coarse shell material”.

23. These soft-sediments support low species abundance and diversity, characterized by small motile deposit feeders, predators and scavengers – such as small gastropods and hermit crabs - and small suspension feeding bivalves. These species are likely to be tolerant to suspended sediments and deposition of sediment as they live in benthic sediments that are regularly disturbed, with sediments resuspended and re-deposited to the seabed, and occur in nearshore areas with high river runoff and high background levels of suspended sediment.

24. Two types of rock outcrops (hard rock and mudstone) were recorded. Mudstone outcrops were soft and very crumby and supported very few organisms. In contrast, hard rock outcrops of low to moderate relief were characterised by high proportions of sessile suspension feeders (dominated by bryozoans and sponges) and primary producers (dominated by turf- forming red macroalgae). Although hard rock outcrops comprised only a small amount of the available seabed (<6%), they represented a substantive

component of the overall abundance and diversity of the nearshore region (25% of specimens and 61% of all species).

25. Rock outcrop-associated species, particularly bryozoans, erect and massive sponge growth forms, and large canopy forming species, such as kelps and seaweeds, are likely to be susceptible to small increases in suspended sediments.

26. Macroalgal assemblages on these rocky reefs were dominated by turf-forming red algal species along with filamentous and branching red macroalgal species that have sediment-trapping morphologies that enable them to dominate space under high depositional conditions. Similarly, the brown algae, Zonaria turneriana, was commonly seen across these rocky outcrops. This species grows on both rocks and sand and can cope with periods of sediment burial. Although no kelp forests or Ecklonia plants (ie the common kelp forest species) were recorded on these low patch outcrops, isolated Ecklonia plants were recorded on the more extensive low to moderate relief outcrop off Hawera.

Response to issues raised in evidence, submissions or expert conferencing that have now been resolved.

27. In their peer review SKM (on behalf of the EPA) stated that the nearshore survey did not present information on the North and South Traps. North and South Traps and Graham Bank were not sampled in this survey, but are addressed in the evidence of Dr Dan McClary.

28. However, on the 6th March 2014, TTR provided me with habitat maps and associated video footage of North and South Traps collected in 2005 by ASR Ltd. North and South Traps were identified as discrete rock outcrops located in 20 m water depth but in some sections rise to approx. 10 m below the sea surface (particularly on the northern sections of North Traps).

29. Although video of the North and South Traps was not able to be linked with the bathymetric map-display, the series of short video clips taken by ASR Ltd in 2005 and presented to all participants at the expert benthic ecology Conference (Friday the 21 March - Part 2) clearly showed: i) extensive urchin-barrens (areas devoid of macroalgae due to urchin grazing), dominating much of the lower-relief areas of these features, ii) discrete patches of the native green alga, Caulerpa flexilis, at a range of locations across the Traps. Patches ranged from healthy plants to completely denuded areas with only the underlying rhizomes present, while other areas show rhizome mats with new small shoots re-growing. This variability in health is indicative of ongoing disturbance, possibly due to

storms and/or periods of sediment burial and exposure. iii) Variable sized patches of moderately-dense Ecklonia forests were seen on the upper higher-relief sections of these reefs. iii) In deeper areas around the base of these features, rock-and-sand gulley features were seen, with narrow rocky-ridge supporting isolated Ecklonia plants, and some sponges and other sessile invertebrates iv) Adjacent to these features were expansive areas of mobile soft- sediments.

30. According to the revised sediment plume modelling, experts agreed (Joint statement Part 2, pg11) that the North and South Traps are beyond the primary area regularly exposed to elevated concentrations of mining-derived suspended sediments, and so are unlikely to be affected by mining activities. However due to their regional significance as having outstanding coastal value, it was agreed that these areas should be monitored to detect potential effects of mining.

31. In their peer review report, SKM (for the EPA), along with a number of other submitters, including Douglas Gordon (on behalf of fisheries submitters) and Karen Pratt, stated that the nearshore and Patea Shoals reports did not address impact sensitivities/thresholds in relation to changes in the physical environment. As mentioned above, NIWA was contracted to provide baseline information on the types of habitats and ecological assemblages present in these areas, but was asked not to address risks or impacts as these were to be assessed independently by a non-NIWA contractor (Dr Dan McClary) and will be presented in Dr McClary’s expert testimony.

32. In the joint statement on Ecological Effects, with respect to impact sensitivities and thresholds, experts agreed that some species within this region are likely to be tolerant to sediment deposition (for e.g. some soft-sediment bivalves, turfing red algae and commonly occurring brown and green seaweeds such as Zonaria turneriana and Caulerpa flexilis), but that sensitivity thresholds are simply not known for many of the species recorded from this region. However it was agreed (Joint statement Part 2, pg9) that we do know a lot about the types of communities present and their functional roles (e.g., suspension vs deposit feeders etc.) to predict how community function might change.

33. Douglas Gordon also stated in his evidence that our “analyses do not comment on whether the plume would contain any sediments or elements that are hostile to the organisms” and that “mixing a cocktail of heavy metals, is not dealt with”. The amount or importance of heavy metals was not assessed in the benthic ecology surveys, but the experts at the second expert conferencing session on benthic ecology (paragraph 72) agreed that

“concentrations of nickel and copper in the discharged seawater were unlikely to negatively affect the recolonisation of the seafloor”.

34. The technical review by SKM (for the EPA) and the Department of Conservation submission stated that outputs of the SSC modelling are from an outdated interim report and do not correspond to final outputs in Hadfield (2013). The nearshore survey did select sampling sites and the extent of the survey based on an out-dated interim report, but this was the best available data at that time the survey was undertaken. Knowledge on the types of habitats and benthic assemblages present along this stretch of coast is still relevant to potential nearshore impacts. Importantly, these sites still have the same habitats and organisms irrespective of what models are run. Experts agreed that based on Hadfield’s recent models, mining-derived suspended sediments would not have a significant effect on this nearshore region (Joint statement, Part 2 attachment: Hadfield report to Benthic Ecology Experts.pdf), but these predicted physical parameters should be measured as a part of a monitoring program to determine their actual values (Joint statement Part 2, pg17, paragraph 89).

35. Karen Pratt in her submission raised several issues regarding Ministry for the Environment’s defined Sensitive species list, but inaccurately defined more sensitive habitats than identified by the benthic ecology reports. For example, i) Euchone sp A do not have calcareous tubes and are not a sensitive species as defined/listed by the Ministry of the Environment, therefore many of the comments/issues raised around this point are not relevant to this system. ii) Similarly, although sponges and brachiopods were recorded in the offshore biogenic habitats, no sponge gardens or brachiopod beds per se were recorded within the Patea Shoals or Nearshore regions (Beaumont et al., 2013 and Anderson et al., 2013). iii) In my evidence I stated that three sensitive habitats were recorded in the Patea Shoals region. However based on the terminology of sensitive species defined by the Ministry of the Environment, I refine this statement to include only two sensitive and spatially overlapping habitats. These included beds of large bivalve molluscs (i.e. the Tucetona laticostata beds offshore in depths of approx. 45-80 m) and bryozoan beds (i.e. the bryozoan rubble habitats offshore in 60-80 m water depth). iv) The third sensitive species I had previously listed was inner-shelf beds of the small dog , modesta. However this species has a maximum shell size of approx. 3 cm so would not be considered a large bivalve as defined in the Ministry for the Environment’s sensitive species list.

36. Recent results from the Optical properties models by Matt Pinkerton indicated a reduction in light levels that might impact on benthic primary production (Fig. 6 of Optical Properties report dated 18 March). Benthic microalgae were visible on the seabed at several nearshore sites, particularly sites at or

adjacent to the Whanganui sewage outflow pipe. Some benthic diatoms were also recorded in the river mouth at site 15 where a high number of deposit feeding sand dollars were collected. However no surveys were undertaken to quantify benthic microalgae within the sediments of this region.

37. The area where there is sufficient light for benthic photosynthesis (offshore of Hawera/Patea in 20-40 m water depth) had no visible benthic microalgae - based on still images and deck photographs of the surface sediments collected in cores.

38. Macroalgae was also ecologically absent from this 20-40 m depth zone, within both mining and non-mining sites across the midshelf.

39. Experts agreed that monitoring benthic microalgae would prove difficult due to high spatial and temporal variability, but that analysing chlorophyll-a to distinguish between fresh benthic and decaying pelagic pigments would be straight forward and would determine the relative importance of these two sources of production (Joint statement Part 2, pg5, point 19).

Response to issues raised in evidence, submissions or expert conferencing that have not been resolved.

40. Evidence submitted by Dr Brain Paavo, on behalf of KASM, raised a series of issues regarding the adequacy of the two benthic ecology studies to support evidence based decision making. These issues were also cited by Associate Professor Slooten in her evidence [pg 3 paragraph 16] in reliance on Dr Paavo). It is unclear at the time of writing this executive summary what areas of disagreement still exist as following the expert conferencing Dr Brian Paavo refused to sign the Joint Statement-Part 1. As a result, I address several key issues below that Dr Paavo identified in his evidence.

41. Evidence submitted by Dr B. Paavo, on behalf of KASM, criticizes the sampling design, specifically relating to the time taken to sample the entire survey and that sites were systematically sampled with respect to bathymetry and a southeastern progression. The sampling design undertaken for both surveys reflects the best available information given several temporal constraints. The initial survey design for the mining project was to survey the seabed inside and adjacent to TTR’s original extraction area. After sampling began, TTR requested that we include sites further offshore to examine inside and outside of the initially proposed deposition and FPSO sites, designated offshore in water depths of approx. 60-80 m. These sites were subsequently surveyed and identified a diverse bryozoan rubble habitat. TTR, when informed of these findings, proposed an alternative deposition sites to the south-east in 40-50 m water depth, and

requested the inclusion of sites inside and outside this new area – later identified as the bivalve rubble habitat. Each of these areas is indicated in Figure 2 of Beaumont et al., 2013. Further sites were also added to the south-east as initial plume effects were examined. This sequence of planning adjustments in combination with the extremely arduous task of working offshore on the exposed west coast meant that the sampling design although spatially intensive was not temporally optimal. This criticism is not disputed. We have clearly stated this in the report, and addressed and clarified this fact in the review-phase of our reporting.

42. However, this is the best available data and even if we were able to go back and redesign the survey I do not believe the spatial patterns would differ. Offshore biogenic habitats would still be offshore, patchy rocky reefs would still occur inshore, while wormfields and rippled sands would still occur where they do. For wormfields, this point is validated by decadal comparisons with Page et al., 1993.

43. In addition, due to extremely difficult weather conditions, equipment failure and other issues, numerous sites were resurveyed in time (44 video sites; 9 infaunal core sites). No observed temporal difference in seabed geomorphology, habitat type or biological composition was found for these sites, with the exception of an observed layer of silt seen at five inshore sites, following storm events.

44. Consequently the time frame used although not optimal, was deemed acceptable for the purposes of providing a baseline description of benthic habitats and assemblages across the region. I believe that the benthic surveys carried out provide substantial spatial information on the types of habitats present, their distributions and the associated benthic infaunal and epifaunal communities, and I believe that they provide adequate information to support evidence based decision making. However, these surveys were not temporal studies of the natural changes of these systems. I would therefore recommend more detailed temporal studies be undertaken within a BACI type design for any benthic monitoring purposes.

45. At the conclusion of the expert conferencing Part 1, a joint statement addressing A) Methodological adequacy to support evidence-based decision making, and B) Levels of uncertainty around predicted effects, was signed by all benthic ecology experts except Dr Brian Paavo. I do note however that in the signed joint statement part 1, all of the participating experts (except Kristina Hillock who refrained from comment) agreed that the existing spatial ecological data provided adequate information to support evidence based decision making but also agreed that 1-2 years of temporal sampling was required to determine seasonal variability as part of a baseline monitoring survey.

46. Evidence submitted by Dr Brain Paavo, on behalf of KASM, criticized the sampling design in that it did not account for deeper mature communities. Due to the variable hardness of the seabed, only the top 5 cm of core sediments were used for the region-wide site comparisons. This was deemed adequate as the majority (89% in this study) of infaunal organisms occur in the top few cm’s. Comparisons of deeper vertical sections were also undertaken where collected, but these deeper sections contained very few specimens (<2% in the 10-15 cm strata). Deeper sediments had the same suite of species found in surface sediments, just much lower numbers. However, as Euchone sp A lives in buried worm tubes that are often 4 times longer that the worm itself, Euchone sp A densities per volume were also calculated over the entire core depth. No information is available on the infauna that might occur in sediments deeper than 23 cm, but I note that there was no evidence, based on close inspection of high resolution still images of the seabed, to indicate that these types of deeper assemblages were present (e.g. mantis shrimp burrows, exposed siphons or burrows of deeper buried species).

47. Evidence submitted by Dr Brian Paavo, on behalf of KASM, criticizes the study for not recording taxa to species, but rather that these studies lumped taxa within families, further stating that “this fundamental ignorance weakens the biodiversity data presented”. With the exception of Dr Paavo, all other experts agreed that all infauna and epifauna specimens that were collected in the benthic ecology studies were identified to the lowest taxonomic level practicable that would enable between-site comparisons (Joint statement Part 1, pg 3, paragraph 12). I believe the results of these studies provide a significant contribution to our understanding of epifaunal and infaunal species and assemblage types within the South Taranaki Bight and continental shelf communities of New Zealand’s West Coast.

______Dr Tara Anderson

29 March 2014