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IN THE MATTER of the Resource Management Act 1991 AND IN THE MATTER of a Board of Inquiry appointed under section 149J of the Resource Management Act 1991 to consider The New Zealand King Salmon Co. Limited's private plan change requests to the Marlborough Sounds Resource Management Plan and resource consent applications for marine farming at nine sites located in the Marlborough Sounds STATEMENT OF EVIDENCE OF ANGUS LINCOLN MACKENZIE IN RELATION TO WATER COLUMN EFFECTS: HARMFUL ALGAL BLOOMS FOR THE NEW ZEALAND KING SALMON CO. LIMITED JUNE 2012 D A Nolan / J D K Gardner-Hopkins Phone 64 4 499 9555 Fax 64 4 499 9556 PO Box 10-214 DX SX11189 Wellington TABLE OF CONTENTS EXECUTIVE SUMMARY QUALIFICATIONS AND EXPERIENCE 1 SCOPE OF EVIDENCE 3 THE PROPOSAL 4 HARMFUL ALGAL BLOOMS: AN INTRODUCTION 4 NOTABLE HARMFUL ALGAL BLOOMS IN NEW ZEALAND COASTAL WATERS 6 PHYTOPLANKTON ECOLOGY AND NUTRIENT CHEMISTRY OF THE MARLBOROUGH SOUNDS WITH SPECIAL REFERENCE TO HARMFUL ALGAL BLOOMS 11 OVERSEAS EVIDENCE OF LINKS BETWEEN HABS AND SEA CAGE FISH FARMING 20 Scotland 21 Chile 22 Korea 24 USA and Canada 24 Japan 25 Scandinavia 26 Baltic Sea 28 A SUMMARY OF THE OVERSEAS EVIDENCE LINKING HARMFUL ALGAL BLOOMS AND SEA CAGE FISH FARMING 28 POTENTIAL EFFECTS OF FISH FARM EFFLUENTS WITH RESPECT TO HARMFUL ALGAL BLOOMS IN THE MARLBOROUGH SOUNDS 29 MONITORING RECOMMENDATIONS 36 SUBMISSIONS 36 CONCLUSIONS 39 Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 EXECUTIVE SUMMARY A. My work in relation to New Zealand King Salmon Company Limited (NZ King Salmon) has been to undertake an assessment of the effects of the company's proposal on the potential for harmful algal blooms (HABs) in the Marlborough Sounds. This includes a discussion of what is understood internationally about the relationship between sea cage fish farming and HABs, the New Zealand experience of HABs over the last several decades, and what this means in relation to NZ King Salmon's proposed farm sites. B. My evidence provides a brief discussion of the ecology of phytoplankton communities throughout New Zealand and the Marlborough Sounds with a focus on toxic and noxious species. I discuss the nature of the water column and associated phytoplankton in different parts of the Sounds and what this means in relationship to the proposed farms. I also provide a synopsis of the international literature on the association between the incidence of HABs and effluents from sea cage fish farming operations. C. Frequent blooms of planktonic micro-algae in coastal waters are a natural and essential ecosystem process. Occasionally blooms of some species (usually flagellates) affect human interests and so become known as harmful algal blooms (HABs). There have been many accounts of HABs in New Zealand coastal waters but few if any of these can be attributed to anthropogenic effects on water quality. D. Globally, increased exploitation and awareness of the ecology of coastal seas has revealed that the potential for HABs is greater than formerly realised. HAB events of various types are common in New Zealand and many that do not cause significant environmental or economic effects go largely unnoticed. E. A link has been made between coastal seawater nutrient enrichment and eutrophication in some counties although the relationship is complex and depends on the specific environment and micro-algae involved. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 The record of major HABs shows that coastal eutrophication is not a factor in their incidence in New Zealand. F. Effluent emissions from sea cages is often cited as a potential cause of HABs but there is no evidence from routine phytoplankton monitoring programmes that salmon cages in the Marlborough Sounds have contributed to the generation of HABs in this region to date. G. Neither is there convincing evidence from the international literature of an association with HABs and sea cages, except in some shallow, confined and poorly flushed locations subject to heavy nutrient loads. However it is acknowledged in several studies that there is an inadequate understanding of how nutrient discharges from sea cages affect the structure and function of the wider pelagic ecosystem. H. Pelorus and Queen Charlotte Sounds differ most markedly in the influence that oceanic sea water and freshwater inflows have on the physical structure and nutrient chemistry of the water column and phytoplankton communities. Both Sounds usually support dinoflagellate dominated communities in summer. I. Inner Queen Charlotte Sound often experiences higher biomass blooms, probably due to nutrient enrichment via inflows of upwelled water entering the sound through Tory Channel. Surface waters in Tory Channel contain high levels of nitrate throughout the year. The various inlets and bays where reduced flushing and strongly stratified water columns predominate are preferred flagellate habitats and may contain high numbers of resting cysts in the sediments. These environments are sometimes the origin of more widespread HABs. J. Inner Pelorus and Kenepuru Sounds are strongly influenced by nutrient enrichment from the Pelorus and Kaituna Rivers which is the reflected in the turbidity, high phytoplankton biomass and productivity of inner sound waters. Outer Pelorus Sound is influenced by oceanic water from Cook Strait and wind and tide induced upwelling of nutrient enriched waters. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 K. With the exception of the Papatua Site (Port Gore) the proposed farms are sited in deep, high current locations with well mixed water columns where ambient inorganic nutrient concentrations are naturally high. These are not the type of environments conducive to HAB development. Although the Papatua Site does not have high current flows, it is situated on the margins of Cook Strait and is near regions (Capes Lambert and Jackson) typified by high current and turbulent well mixed nutrient-rich waters. L. It is not expected that the increased nitrogen loads with their sources spread over a wide geographic area in naturally nutrient rich environments will lead to an increase in problems with HABs. The lack of evidence of an association between HABs and existing salmon farms in the Marlborough Sounds and Stewart Island suggests the effects of the proposed increased nutrient inputs will be minimal. An appropriate water column monitoring programme should be able to detect any significant changes in Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 this regard. Page 1 of 41 QUALIFICATIONS AND EXPERIENCE 1 My full name is Angus Lincoln MacKenzie. 2 I hold a BSc (Hons) from the University of Otago. 3 I am an elected member of the council of the International Society for the Study of Harmful Algae (ISSAH) and serve on the editorial board of the journal, "Harmful Algae". 4 I am currently a Senior Research Scientist at the Cawthron Institute (Cawthron), in Nelson. I have held this position for the last 32 years. My work at Cawthron has focused primarily on the ecology, productivity, physiology, taxonomy, biochemistry and toxicology of marine phytoplankton and the effects of aquaculture on the marine environment. 5 Prior to working at Cawthron I was employed as a Research Technician at Freshwater Section of DSIR for three years. My area of work at DSIR was involved with research on the eutrophication of NZ lakes. 6 My expertise includes aquatic ecology and environmental effects of aquaculture; phytoplankton systematics, ecology and physiology; microalgal biotoxin analytical methodologies; shellfish metabolism and physiology; biogeochemical processes in environments; biosecurity risk assessment. coastal and freshwater I have authored or co- authored more than 80 primary publications in refereed journals, and 135 consultancy reports, popular publications and conference papers on various aspects of coastal marine ecology, harmful algal blooms (HABs), aquaculture development and biosecurity. 7 I have been contracted as an expert witness on one previous occasion to provide evidence relating to coastal phytoplankton ecology to a Council Resource Consent hearing. 8 This evidence is given in support of a request for a change to the Marlborough Sounds Resource Management Plan and nine resource Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 2 of 41 consent applications, lodged with the Environmental Protection Authority (EPA) 3 October 2011 and collectively referred to as 'the proposal'. 9 My work in relation to New Zealand King Salmon Company Limited (NZ King Salmon) has been to undertake an assessment of the effects of the company's proposal on the potential for harmful algal blooms (HABs) in the Marlborough Sounds. This includes a discussion of what is understood internationally about the relationship between sea cage fish farming and HABs, the New Zealand experience of HABs over the last several decades, and what this means in relation to NZ King Salmon's proposed farm sites. The work was carried out in collaboration with Cawthron colleagues Dr Paul Gillespie and Mr Ben Knight. I am one of the authors of the report1 appended to the proposal application, and refer to that report in this evidence as the Water Column Effects Report/August 2011. My evidence is an extension of information provided in this report and references contained therein. 10 In preparing this brief of evidence I have reviewed the evidence of Dr Paul Gillespie and Mr Ben Knight on the water column effects of the proposed developments and the international literature on what is known of the relationships between coastal eutrophication, sea cage fish farming and HABs. I have also reviewed unpublished material that relates to the nature and incidence of HABs in New Zealand and the Marlborough Sounds in particular. 11 I have read the Code of Conduct for Expert Witnesses as contained in the Environment Court of New Zealand Practice Note 1 November 2011 and I agree to comply with it. My qualifications as an expert are set out above. I confirm that the issues addressed in this brief of evidence are within my area of expertise. I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed. 1 Gillespie, P., Knight, B.R., MacKenzie, L. 2011. The New Zealand King Salmon Company Limited: Assessment of Environmental Effects-Water Column. Prepared for the New Zealand King Salmon Co. Ltd. Cawthron Report No. 1985. 79 p. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 3 of 41 SCOPE OF EVIDENCE 12 The structure of my evidence is as follows: 12.1 The Proposal 12.2 Harmful Algal Blooms: An Introduction 12.3 Notable Harmful Algal Blooms in New Zealand Coastal Waters 12.4 Phytoplankton Ecology and Nutrient Chemistry of the Marlborough Sounds With Special Reference to Harmful Algal Blooms 12.5 Overseas Evidence of Links Between Harmful Algal Blooms and Sea Cage Fish Farming 12.6 12.5.1 Scotland 12.5.2 Chile 12.5.3 Korea 12.5.4 USA and Canada 12.5.5 Japan 12.5.6 Scandanavia 12.5.7 Baltic Sea Summary of the Overseas Evidence Linking Harmful Algal Blooms and Sea Cage Fish Farming 12.7 Potential Effects of Fish Farm Effluents with Respect to Harmful Algal Blooms in the Marlborough Sounds 12.8 Monitoring Recommendations 12.9 Submissions Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 4 of 41 12.10 Conclusions THE PROPOSAL 13 I confirm that my evidence is based on the project proposal as described in chapter 3 of the Sustainably Growing King Salmon Assessment of Environmental Effects prepared by Boffa Miskell Limited October 2011; and chapter 3 of the Sustainably Growing King Salmon White Horse Rock Assessment of Environmental Effects prepared by Boffa Miskell Limited October 2011. HARMFUL ALGAL BLOOMS: AN INTRODUCTION 14 A high biomass of a single or a limited group of species of planktonic micro-algae is generally referred to as an algal bloom. Blooms are the result of the transient dominance by one or a few species over others, due to favourable physical (e.g. salinity/temperature), chemical (e.g. nutrients) or biological (e.g. life cycle behaviours) factors that enhance their growth. Algal blooms are essential to the normal functioning of the marine ecosystem. For example the spawning of many invertebrates is timed to take advantage of the extra algal-food resources available during blooms. 15 There are some algal species which through various mechanisms (often the production of poisonous secondary metabolites),can cause natural mass mortalities of marine flora and fauna, kill fish in sea cages or contaminate shellfish with toxins. HABs are usually natural events, however, there is a growing scientific consensus (Anderson et al., 20082;Heisler et. al., 20083) that degraded coastal sea-water quality can promote the development and persistence of HABs and is one of the reasons for their apparent global expansion. 2 The Baltic Sea, Aegean Anderson, D.M. et al., 2008. Harmful algal blooms and eutrophication: Examining linkages from selected coastal regions of the United States. Harmful Algae 8: 39-53. 3 Heisler J. et al., 2008. Eutrophication and harmful algal blooms: A scientific consensus. Harmful Algae 8: 3-13. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 5 of 41 Sea, Northern Adriatic and Black Sea all have regions where increases in HABs have been coincident with increases in nutrient loading from urban, industrial and agricultural sources. Comparable situations are not known in New Zealand and it is unlikely that eutrophication is an important factor in the incidence of HABs here, except perhaps in some small coastal impoundments (e.g. Jones & Rhodes 19944) 16 Most HAB species are flagellates, i.e. they belong to a number of different taxonomic groups that have whip-like flagella which enable them to swim and rapidly change position within the water column in response to light, nutrients, temperature and salinity gradients. Non-motile diatoms usually dominate the highest biomass phytoplankton blooms (usually in late winter-spring and autumn) which represent the annual productivity maxima, but few diatoms have harmful effects. 17 Because of their motility, the growth of flagellate dominated phytoplankton communities are favoured in locations where the water column becomes strongly stratified in summer, due to the buoyancy of warm surface waters overlying colder deeper waters. Vertical salinity gradients also play an important role in the stratification of coastal sea waters. The development of a strongly stratified water column occurs more frequently in sheltered embayments with weak current flows, minimal turbulence and long water residence times. 18 Good quantities of dissolved silica are an essential nutrient for diatoms because of their silica impregnated cell walls. Dissolved silica is not required for the growth of flagellates. Consequently, flagellate growth is often favoured under conditions where silica becomes a limiting nutrient for diatoms. Long term changes in the N/P/Si ratios have been shown to correlate with changes in the ratio of abundance of diatoms and flagellates in large drowned river valley estuarine systems similar to the 4 Jones, J.B. and Rhodes, L.L. (1994) Suffocation of pilchards (Sardinopssagax) by a green microalgal bloom, Wellington Harbour,New Zealand, December 1993. New Zealand Journal of Marine and Freshwater Research 28. 379-384 Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 6 of 41 Marlborough Sounds (Smayda & Borkman 20055 ). It has been suggested that because the nutrient inputs from sea cage farms are rich in nitrogen and phosphorus, but deficient in silica, these effluents can favour the growth of flagellate dominated HABs. NOTABLE HARMFUL ALGAL BLOOMS IN NEW ZEALAND COASTAL WATERS 19 Harmful algal blooms in New Zealand can be localised events occupying only a small bay or inlet, or very extensive phenomena where cells are transported, and resident populations established, around much of the coastline of either main island. Blooms originating in the North Island have been observed to cross Cook Strait and intrude into the Marlborough Sounds. There are a few locations where resident populations of particular species result in the formation of HABs every year and other locations which are rarely, if ever, affected. Some species may for a period of several years become a major component of the phytoplankton only to eventually decline in abundance and disappear. The ability to form long-lived resting cysts that reside in the sediments is an important feature of the life cycle of some HAB species that enables their establishment and long term residence. Over the last 20 years there have been numerous minor HAB blooms that have required some response from the aquaculture industry or food safety regulators, and a number of very large events which have had significant economic and social consequences. The most important major events that have been documented are listed below: 19.1 In the years of 1860, 1900-1901, 1956, 1960, 1964, 1979, and 1981 there were recorded accounts of Tasman Bay slime blooms, which were caused by dinoflagellate mucilage exudates 5 Smayda, T., Borkman, D. 2005. Multi-decadal changes in the diatom:flagellate ratio and Si:N and Si:P ratios in Narragansett Bay, and influence of Si:N supply ratios on diatom species competition. In Proceedings of the Open Science Meeting on HABs and Eutrophication, 7-10 March 2005, Baltimore Maryland, USA.p 60 of abstracts. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 7 of 41 associated with massive fish kills and a hindrance to fishing activities (MacKenzie et al., 20026). 19.2 In the summer of 1982-83, an intense and persistent diatom bloom (Ceratulina pelagica) on the North Island east coast caused widespread shellfish and some fish mortalities, probably through anoxia (Taylor et al., 19857) 19.3 In January 1989 in Big Glory Bay, Stewart Island a Heterosigma bloom occurred, that resulted in a loss of more than 600 tonnes of farmed salmon. This was a costly blow to the developing industry (Chang et al., 19908; MacKenzie, 19919). The bloom took place after an unusually long period of fine calm weather which reduced flushing and water exchange. It is not possible to say whether the salmon farm effluents played a significant role in stimulating this bloom, but it was noted at the time that high nutrient concentrations occurred in Paterson Inlet which was attributed to incursions of fertile oceanic water. To our knowledge there has been no repetition of major algal bloom events in Big Glory Bay since 1989, although a routine phytoplankton monitoring programme with weekly sampling has been in place ever since and salmon production is now around 3,000 tonnes per year. 19.4 During the 1992-93 summer a dinoflagellate bloom (Karenia sp.) in Northland and the Hauraki Gulf contaminated shellfish with brevetoxins and a large number of people became ill from eating them. There were reports of marine fauna mass mortalities in 6 MacKenzie, L., Sims, I., Beuzenberg, V., Gillespie, P. 2002: Mass accumulation of mucilage caused by dinoflagellate polysaccharide exudates in Tasman Bay, New Zealand. Harmful Algae 1. 69-84. 7 Taylor, F.J., Taylor, N.J., Walsby, J.R. 1985.A bloom of the planktonic diatom Cerataulinapelagica, off the coast of Northeastern New Zealand in 193, and its contribution to an associated mortality of fish and benthic fauna. Internationale Revue der gesamten Hydrobiologie und Hydrographie. 70(6): 773-795. 8 Chang, F. H., C. Anderson and N. C. Boustead 1990: First record of a Heterosigma (Raphidophyceae) bloom with associated mortality of cage-reared salmon in Big Glory Bay, New Zealand. New Zealand Journal of Marine and Freshwater Research 24: 461-469. 9 MacKenzie, A.L. 1991. Toxic and noxious phytoplankton in Big Glory Bay, Stewart Island, New Zealand. Journal of Applied Phycology 3: 19-34. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 8 of 41 Northland and prolonged closures of shellfish harvesting nationwide (MacKenzie et al., 199510). This event resulted in the commencement of the national marine shellfish biotoxin and toxic phytoplankton monitoring programmes. 19.5 In 1993-1994 blooms of the toxic dinoflagellate Alexandrium minutum in outer Pelorus Sound resulted in extensive and prolonged closures of mussel harvesting within the sound, resulting in significant losses to growers, processors and their employees. These were relatively minor events but unreliable and inaccurate toxin testing methods used at the time made them appear more serious than they were. 19.6 During the summers of 1993-94 and 1995-96 blooms of Karenia selliformis contaminated Foveaux Strait oysters with a toxin (now known as gymnodimine) and caused widespread mortalities of fish and shellfish in Southland and the east coast of the South Island, possibly as far north as Port Underwood (MacKenzie et al., 199611). 19.7 In March-April 1996 and 1997 the first blooms of the saxitoxin producing dinoflagellate, Alexandrium catenella were identified in the Bay of Plenty associated with high levels of saxitoxins in surf clams. Since then blooms of A. catenella and shellfish contamination have become common on the North Island east coast from the Bay of Islands to the Bay of Plenty, most recently in January 2012. 19.8 During March 1998 a bloom of Karenia brevisulcata in Wellington Harbour caused mass mortalities of marine fauna and flora and 10 MacKenzie A. L., L. L. Rhodes, D. Till, F. H. Hoe Chang, H. Kaspar, A. Haywood, J. Kapa and B. Walker 1995: A Gymnodinium sp. bloom and the contamination of shellfish with lipid soluble toxins in New Zealand, Jan - April 1993. In P. Lassus, E. Erard, P. Gentien and C. Marcaillou [Eds] Harmful Marine Algal Blooms Lavoisier Science Publishers, Paris pp. 795-800. 11 MacKenzie, L., A. Haywood, J. Adamson, P. Truman, D. Till, M. Satake and T. Yasumoto. 1996. Gymnodimine Contamination of Shellfish in New Zealand. In: Yasumoto,T., Oshima, Y., and Fukuyo, Y. (Eds) Harmful and Toxic Algal Blooms. Intergovernmental Oceanographic Commission of UNESCO. pp 97-100. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 9 of 41 adversely affected the Mahanga Bay shellfish hatchery (Chang, 199912). The bloom was preceded by reports of dead fish (tuna, bill-fish) abalone, seals and penguins along the Wairarapa coast. 19.9 In May 2000 the toxic dinoflagellate, Gymnodinium catenatum was first identified in samples from the North Island west coast. Over subsequent months a major bloom developed that spread along the entire coast of the North Island, through Cook Strait and up the east coast as far as Hawke Bay. The bloom impinged on the Marlborough Sounds but did not become established in this area. The contamination of juvenile mussels collected on Ninety Mile Beach (‘Kaitaia Spat’) with resting cysts of G. catenatum, halted the transport of this valuable resource to the Marlborough Sounds. This had a major effect on the productivity of the mussel industry (MacKenzie & Taylor 2004)13. Annual blooms occurred in Hawke Bay until 2004, after which it gradually dwindled in abundance and eventually disappeared. The last cells of G. catenatum were seen in Hawke Bay in 2007. 19.10 During the spring of 2002 Karenia spp.blooms (K. mikimotoi, K. brevisulcata, K. concordia) caused mass mortalities of fish (flounder, mullet etc.) in the Hauraki Gulf and the total loss of cultured abalone on a farm in Kennedys Bay, Coromandel Peninsular (Chang et al., 200114). 19.11 June 2010 a Pseudochattonella verruculosa bloom in inner Queen Charlotte Sound caused substantial mortalities (>200 tonnes) of salmon at the Ruakaka Bay salmon farm. Commercially this was the most serious fish kill event since the 12 Chang, F.H., 1999. Gymnodnium brevisulcatum sp. nov.(Gymnodiniales, Dinophyceae), a new species isolated from the 1998 summer bloom in Wellington harbour, New Zealand.Phycologia 38(5): 377-384. 13 MacKenzie, A.L., Taylor, M. 2004. Risk assessment of the transfer of Kaitaia spat contaminated with Gymnodiniumcatenatum cysts. A report for the NZ Mussel Industry Council, Cawthron Report No. 868. 14 Chang, F.H. et al., 2001. Occurrence and distribution of Karenia brevisuclata (Dinophycae) during the summer toxic outbreaks on the central east coast of New Zealand. Phycologia 40: 215-222. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 10 of 41 1989 Big Glory Bay bloom (MacKenzie et al., 2011a15). The bloom was generated in the Grove Arm and throughout its duration was confined to the inner sound, with its seaward limit extending onto the farm at Ruakaka Bay. 19.12 During February-April 2011the first recorded bloom of Alexandrium catenella occurred in Tory Channel which eventually spread to other regions of Queen Charlotte Sound and resulted in shellfish harvest closures of up to three months (MacKenzie et al.,2011b16). A sampling survey of seafloor sediments showed that A. catenella resting cysts, were widely distributed around the Sound with highest densities in Opua Bay, Tory Channel. In February 2012 a bloom of A. catenella again developed in Opua Bay but inclement weather during early autumn prevented the bloom from becoming more widespread. 19.13 An example of a chronic HAB phenomena, is the annual appearance of the resident toxic dinoflagellate, Dinophysis acuminata in Port Underwood. Without exception over 20 years of monitoring, blooms of this species have occurred very year, usually in spring or late summer. Fortunately the toxicity of this species is relatively mild and only occasionally have harvest closures been necessary when cell numbers have become exceptionally high. 15 MacKenzie, L., Smith, K. F., Rhodes, L. L., Brown, A., Langi, V., Lovell, G., Preece, M. 2011a. Mortalities of sea cage salmon (Oncorhynchustshawytscha) due to a bloom of Pseudochattonella verruculosa (Dictyophyceae) in Queen Charlotte Sound, New Zealand. Harmful Algae 11: 45-53. 16 MacKenzie, L., Harwood, T., Boundy, M., Smith, K, Knight, B., Jiang, Weimin, McNabb, P., Selwood, A., van Ginkel, R., Langi, V., Edgar, M., Moisan, C. 2011b. An Alexandrium catenella bloom and associated saxitoxin contamination of shellfish, Queen Charlotte Sound, March-June 2011. A report for MAF Food Safety. Cawthron Report No. 1945. 38pp. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 11 of 41 PHYTOPLANKTON ECOLOGY AND NUTRIENT CHEMISTRY OF THE MARLBOROUGH SOUNDS WITH SPECIAL REFERENCE TO HARMFUL ALGAL BLOOMS 20 The Marlborough Sounds with their numerous sheltered inlets and bays, broad open reaches and proximity to the deep turbulent waters of Cook Strait provide a diversity of physical and chemical water column conditions that shape the species composition, successional patterns and biomass of the phytoplankton. Although phytoplankton communities are highly dynamic, there are consistent seasonal patterns in phytoplankton biomass and species succession that are experienced in the Sounds and throughout the wider region (MacKenzie & Gillespie 198617; Gibbs & Vant, 1997; 18) that are typical of temperate latitudes elsewhere (Figure. 1). 21 There are also consistent spatial differences in the hydrodynamic properties, residence time, light and nutrient conditions of different locations that control the biomass and species composition of phytoplankton communities. The index (ISL) devised by Knight (Gillespie et al., 201119) as a guide to the optimum location of fish farms in the Sounds (i.e. those with a high index value) provides a good illustration of locations where flagellate dominated phytoplankton blooms are most likely to occur (i.e. those with a low index indicative of poor flushing characteristics). The model clearly identifies the sound entrances and channel regions as the most suitable for finfish aquaculture in terms of currents and water depth. These areas are also those which are least likely to experience stable water column conditions conducive to the development of nuisance algal blooms. They are also locations where there is the maximum potential for dilution and dispersion of nutrients emanating from the farms. 17 Mackenzie A. L. and P. A. Gillespie 1986: Plankton ecology and productivity, nutrient chemistry and hydrography of Tasman Bay, New Zealand, 1982-1984. New Zealand Journal of Marine and Freshwater Research 20: 365-395. 18 Gibbs M.M., Vant, W.N. 1997. Seasonal changes in factors controlling phytoplankton growth in Beatrix Bay, New Zealand. NZ Journal of Marine and Freshwater Research 31: 237-248. 19 Gillespie, P., Knight, B.R., MacKenzie, L. 2011. The New Zealand King Salmon Company Limited: Assessment of Environmental Effects-Water Column. Prepared for the New Zealand King Salmon Co. Ltd. Cawthron Report No. 1985. 79p. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 12 of 41 Figure 1. Seasonal changes in (A) water column temperature, (B) nutrients (nitrate + nitrite), and (C) phytoplankton biomass in the Marlborough Sounds. This figure is based on observational data from Tennyson Inlet, Pelorus Sound but these patterns are typical of processes in other embayments throughout the Sounds. The patterns are generally maintained from year to year although the timing, magnitude and species involved vary. 22 Light limitation in late autumn/early winter generally leads to a slowdown in phytoplankton growth and nutrient demand. Consequently concentrations of oxidised forms of nitrogen (nitrate and nitrite), formed by the re-mineralisation of organic nitrogen and nitrification of reduced forms of nitrogen (e.g. ammonium) in the sediments and water column, accumulate and reach their annual maximum. Concurrently during this period water column stratification that has been maintained throughout the summer and autumn breaks down. 23 Diatoms respond rapidly to water column mixing and increases in nitrate (Carter 200420), and in late winter to early spring the annual productivity maximum caused by diatom blooms usually takes place. Throughout the 20 Carter, C.M. 2004. Spatial and Temporal Dynamics of Phytoplankton communities in a Coastal Ecosystem.PhD Thesis. University of Canterbury. 177p. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 13 of 41 spring a succession of diatom blooms may occur until early summer, when warming surface waters stabilise the water column, preventing mixing, and favouring phytoplankton communities dominated by flagellates that can take advantage of vertical gradients of light and nutrients. Flagellate communities usually become established at the density interface (pycnocline), typically at 9-12 metres depth, between deeper, darker, cooler, higher-salinity, nutrient rich layers and warmer, lower-salinity, nutrient depleted but illuminated layers in the upper water column. Because flagellates are able to move between these layers throughout the day and night, they are able to optimise their access to nutrients and light. Often there is a secondary productivity maximum in late summer/autumn, when zooplankton grazing pressure that has built up over the spring and summer is relaxed. 24 Superimposed on this general seasonal pattern are nutrient enrichment and water column mixing episodes brought on by floods, storms, upwelling events and complex biological interactions (competition for nutrients, grazing, allelopathy etc.) that also play important roles in structuring phytoplankton communities. Carter (2004)20 provided evidence that long term El-Nino Southern Oscillation(ENSO) changes in upwelling along the Cook Strait continental shelf can impact phytoplankton dynamics in Pelorus Sound and during strong El-Nino phases this can cause diatoms to persist during the summer. Conversely during strong La Niña phases dinoflagellates tend to become dominant in summer. Changes in ENSO also relate to changes in the magnitude of river inflows, and oceanic and riverine nitrogen sources that underpin phytoplankton productivity are complementary in Pelorus Sound (Zeldis et al., 200821). 25 Pelorus and Queen Charlotte Sounds differ most markedly in the influence that freshwater runoff has on the water column. This is a function of the relative size of freshwater catchment areas of each sound. The ratio of catchment to sea surface area is much greater in Pelorus 21 Zeldis, J.R., Howard-Williams, C., Carter, C.M., Schiel, D.R. 2008. ENSO and riverine control of nutrient loading phytoplankton biomass and mussel aquaculture yield in Pelorus Sound, New Zealand. Marine Ecology Progress Series 371: 131-142. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 14 of 41 Sound than Queen Charlotte Sound. These differences in freshwater inflow are reflected in the water chemistry of the Sounds, especially with respect to salinity fields and the amounts and ratios of essential nutrients (Figure 2). For example, the ratios of inorganic nitrogen to dissolved reactive silicates (essential for diatom growth) are higher in Queen Charlotte Sound than Pelorus Sound (Carter 200422, Mackenzie unpublished data). 26 Because of its importance to the mussel farming industry, most research has been focused on the Pelorus Sound system and there are numerous published papers that deal with various aspects of the hydrology, nutrient chemistry and plankton ecology (e.g. Gibbs et al., 199223; Gibbs and Vant, 199724; Gibbs et al., 200225). It is apparent from some of this research (e.g. Ogilvie et al., 200026) that food depletion during periods of low phytoplankton productivity resulting from nitrogen limitation can be a constraint on mussel productivity in some part of Pelorus Sound. There has been less equivalent research on Queen Charlotte Sound and most existing material is contained in unpublished reports and data sets (e.g. the MSQP phytoplankton/biotoxin monitoring database). 22 Carter, C.M. 2004. Spatial and temporal dynamics of phytoplankton communities in a coastal ecosystem. PhD Thesis. University of Canterbury. 177p. 23 Gibbs, M. M., Pickmere, S.E., Woods, P.H., Payne, G.W., James, M.R., Hickman, R.W., Illingworth, J. 1992. Nutrient and chlorophyll a variability at six stations associated with mussel farming in Pelorus Sound, 1984-85. NZ Journal of Marine and Freshwater Research 26: 197-211. 24 Gibbs, M.M., Vant, W.N., 1997. Seasonal changes in factors controlling phytoplankton growth in Beatrix Bay, New Zealand. NZ Journal of Marine and Freshwater Research 31: 237-248. 25 Gibbs, M., Ross, A., Downes, M. 2002. Nutrient cycling and fluxes in Beatrix bay, Pelorus Sound, New Zealand. NZ Journal of Marine and Freshwater Research 36: 675-697. 26 Ogilvie, S.C., Ross, A.H., Schiel, D.R. 2000. Phytoplankton biomass associated with mussel farms in Beatrix bay, New Zealand. Aquaculture 181: 71-80. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 15 of 41 Figure 2. A typical profile of salinity and nitrate concentrations sampled at stations along the axis of Pelorus Sound from Havelock to Cook Strait. The ticks on the isobars are oriented towards increasing concentrations. The arrow marks the location of the proposed farms at White Horse Rock, Post Office Point, Tapipi and Richmond in the Waitata Reach/outer Pelorus Sound. These data are from observations and analyses carried out in April 1987. The figures show the intrusion of high salinity seawater (>34.5 psu) containing elevated concentrations of nitrate (>1.0 mmol m-3) in bottom waters throughout the inner sound, broaching the surface in the outer sound. The proposed farm sites in Waitata Reach are situated where inner sound waters of an estuarine character meet oceanic waters from Cook Strait. 27 The influence of the Pelorus River on the salinity of near surface waters can extend to the entrance of the sound (Figure 2) where high salinity, nitrate-enriched waters from Cook Strait are lifted to the surface by wind induced upwelling and tidal mixing processes. Relatively high levels of Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 16 of 41 nitrate-N (> 2.0 mmol m-3) can be found in surface waters in this area during summer, when euphotic waters within the rest of the sound are nitrogen depleted. 28 Toxic and noxious algal blooms are uncommon in Pelorus Sound and few shellfish harvest closures have been necessary. Occasionally low levels of domoic acid (produced by planktonic diatoms in the genus Pseudonitzchia) are identified, predominately in the inner Sounds. Closures due to yessotoxin contamination occurred in Kenepuru Sound in 2004. The most extensive and lengthy closures occurred in 1993 and 1994 as the result of blooms of the toxic dinoflagellate Alexandrium minutum in Anakoha Bay. Given this history the risk of serious problems with HABs is regarded as low though the future appearance and establishment of nuisance species, previously unknown in the sound, is always a possibility. 29 From a water column perspective there are biogeographical zones in Queen Charlotte Sound. several distinct These include the inner sound and bays south west of Tory Channel terminating in the Grove Arm, Tory Channel itself, the various bays which extend off Tory Channel (e.g. Onapua Bay, Oyster Bay, Deep Bay), and the large northeastern region of the sound opening on to Cook Strait. Within this latter region East Bay and Endeavour Inlet can probably also be regarded as discrete units. From the limited amount of physical and biological data that is available it is clear that the physical properties, nutrient chemistry and hence the phytoplankton ecology of these regions are usually rather different. The hydrodynamics of Queen Charlotte Sound is complicated by having two entrances that differ in tidal phase which affects estimates of the water residence times. 30 Most of the detailed water column analysis that has taken place in Queen Charlotte Sound has been in the Grove Arm since this area has a history of frequent toxic micro-algal blooms (MacKenzie et al., 199827) and 27 MacKenzie L., P. Truman, M. Satake, T. Yasumoto, J. Adamson, D. Mountfort and D. White 1998: Dinoflagellate blooms and associated DSP-toxicity in shellfish in New Zealand. In B. Reguera, J. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 17 of 41 research has been focussed there. There is a new data set being established by the Marlborough District Council which contains data from four sites in the main channel of Queen Charlotte Sound and one site in Tory Channel. This data set provides useful information on nutrient chemistry and water column structure. 31 High salinities, typical of oceanic waters, are common within the inland reaches of the Grove Arm and the area usually supports a high phytoplankton biomass. Inorganic nutrient concentrations generally follow a predictable seasonal pattern, although bottom waters usually contain high levels of nitrate throughout the year and nutrient enrichment episodes associated with intrusions of nutrient rich oceanic water have been identified. The mechanism of these intrusions is not completely understood. It may involve the onset of estuarine-like circulation during heavy rainfall periods and tidally driven jets of deep bottom water from Tory Channel. During summer a dinoflagellate dominated community prevails for long periods and toxic dinoflagellate blooms have occurred here on numerous occasions in the past28. The area may function as an incubator where blooms develop and are dispersed to other areas. There is good evidence (MacKenzie et al., 2011a29) that the flagellate bloom (Pseudochattonella verruculosa) responsible for killing fish at the Ruakaka farm in June 2010 originated in the Grove Arm, under the influence of a bottom water intrusion event, and spread from there throughout the inner sound. 32 In contrast to the inner sound, Tory Channel is a turbulent and dynamic environment. This is reflected in the biomass and species composition of the phytoplankton which (in the Channel proper) is usually relatively low and dominated by diatoms at most times. High nitrate levels exist in the Blanco, M. L. Fernandezand T. Wyatt [Eds], Harmful Algae Xunta de Galicia and Intergovernmental Oceanographic Commission of UNESCO pp. 74-77. 28 MacKenzie, L., Beuzenberg, V., Holland, P., McNabb, P., Selwood, A. 2004. Solid phase adsorption toxin tracking (SPATT): A new monitoring tool that simulates the biotoxin contamination of filter feeding bivalves. Toxicon 44: 901-918 29 MacKenzie, L., Smith, K. F., Rhodes, L. L., Brown, A., Langi, V., Lovell, G., Preece, M. 2011a. Mortalities of sea-cage salmon (Oncorhynchustshawytscha) due to a bloom of Pseudochattonellaverruculosa (Dictyophyceae) in Queen Charlotte Sound, New Zealand. Harmful Algae 11: 45-53. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 18 of 41 surface waters of Tory Channel throughout the year (Figure 3A) because of persistent upwelling off the eastern coast in the vicinity of Tory Channel entrance (Figure 3B). High levels of nitrate persist throughout the water column of Tory Channel during summer when the photic zone in other parts of the sound is usually depleted of inorganic nitrogen. The longer retention time, water column stability and high fertility of the various embayments that extend off Tory Channel gives these areas a different character where flagellate dominated communities flourish in summer. Figure 3. A) Dissolved inorganic nitrogen (DIN) in surface waters of Queen Charlotte Sound. B) Satellite image of sea surface temperatures showing cold (~ 10°C), high nitrate, upwelling water off the east coast of the Marlborough Sounds on 18 Feb 2012.). 33 A recent example of this was a bloom of the toxic dinoflagellate, Alexandrium catenella (MacKenzie et al., 2011b19) that began and persisted for more than two months (March-May 2011) within the southern Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 19 of 41 Tory Channel bays (Onapua/Opua Bay, Oyster Bay). There is evidence suggesting these bays acted as incubators from which the bloom was dispersed through the Sound, leading to widespread shellfish biotoxin contamination and prolonged harvesting closures. 34 Less is known about the water column and plankton ecology of the northern part of Queen Charlotte Sound, except that it is characterised deeper mixing than the inner sound, and the phytoplankton composition more closely resembles that of Tory Channel. It is expected however that East Bay and Endeavour Inlet will have unique characteristics of their own. Figure 4. Distribution of benthic resting cysts of the toxic dinoflagellate Alexandrium catenella in the Marlborough Sounds. 35 Recent research (MacKenzie unpub.) on the dinoflagellate resting cyst communities within the sediments of Pelorus and Queen Charlotte Sounds has shown these provide a good indicator of fundamental Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 20 of 41 differences in the nature of the phytoplankton communities in these different regions. The sediments within the numerous embayments off Queen Charlotte Sound support more abundant and diverse cyst communities (Figure 4) than similar environments in Pelorus Sound. This probably reflects the different salinity regimes and sources and ratios of inorganic nutrient (N,P and Si ) that provide more favourable dinoflagellate habitats in Queen Charlotte Sound. 36 Fish kills due to algal blooms are not a new phenomenon in Queen Charlotte Sound. The earliest known written record is of a fish kill associated with discoloured water in the Grove Armin 1962. (1982)30 recorded: Hurley “Quantities of fish both dead and otherwise were reported to be present on the beaches. Discussion was held with caretaker of the Domain at Ngakuta Bay, and the following information was obtained. The exact date of the occurrence is not clear but given as approximately the second week in April (1962). During this period the waters were calm and the surface appeared as a reddish brown colour almost bloodlike, no smell being apparent from this substance. Fish (spotties, gurnard, flounders, snapper, dogfish) were reported as being ashore literally gasping and showing evidence of general distress.” OVERSEAS EVIDENCE OF LINKS BETWEEN HABS AND SEA CAGE FISH FARMING 37 The following evidence has been obtained from searches of the international literature pertaining to the effects of fish farming on coastal sea water quality and the incidence of HABs. 30 Hurley, D.E 1982. The ‘Nelson Slime’ observations on past occurrences. NZOI Oceanographic Summary No. 20 October 1982 Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 21 of 41 Scotland 38 Over several decades there was a large increase in farmed salmon production in Scotland, from 598 tonnes in 1980 to 159,000 tonnes in 2001 (‘Marine Scotland’ statistics),accompanied by a concomitant increase in annual N and P waste loadings from fish farms. The Scottish salmon industry is the 3rd largest in the world after Norway and Chile. Rydberg et al., (2002)31 estimated that the total annual N and P loads into Scottish waters from fish farming in 2001 were 7,900 and 1,580 tonnes respectively. Because of emerging problems with a variety of toxic algal bloom phenomena in the 1990s, the focus came on the fish farming industry as a contributor to these problems and several studies (e.g. Smayda 200632) were initiated to investigate this. There were three major concerns which these studies addressed: 38.1 Plant nutrients from fish farms were leading to an increase in algal blooms. 38.2 Plant nutrients from fish farms had disturbed the natural ratios of nutrient elements so favouring the occurrence of toxic over nontoxic species. 38.3 Plant nutrients from fish farms had made potentially toxic algae more poisonous. 39 A report for the Scottish Executive Central Research Unit (2002)33 concluded that the lack of long term monitoring data made it difficult to judge whether the perceived increase in HABs was real and related to expansion in the fish farming industry. The sporadic data that existed did not show conclusively that there has been a wide scale increase in the abundance of organisms responsible for HABs in Scottish waters. 31 Rydberg, L., Sjöberg, B., Stigebrandt, A. 2002. The interaction between fish farming and algal communities of Scottish waters: a review. Draft report to the Scottish Environmental Protection Authority. (cited by Smayda 2006) 32 Smayda, T.J. 2006. Harmful algal Bloom Communities in Scottish coastal Waters: Relationship to Fish Farming and Regional Comparisons: A review. A report for Scottish Executive Environment Group, Natural Scotland Paper 2006/3 168 pp. 33 Scottish Executive Central Research Unit, 2002.Review and Synthesis of the environmental impacts of aquaculture. http://www.scotland.gov.uk/Resource/Doc/46951/0030621.pdf Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 22 of 41 Although the number of incidents of toxicity had increased, this was believed to be probably the result of increased monitoring associated with the expansion of shellfish cultivation. The study concluded, that except in a few enclosed sea-lochs, nutrient enrichment by fish farms was too little relative to natural levels to have the led to an increase in HAB occurrences and that the supply of nutrients to the marine environment was unlikely to be a factor limiting fish farm production in the future. 40 A follow up study was based on a review and analysis of Scottish regional phytoplankton monitoring data carried out by Smayda (2006)29. He concluded that the increase in N and P loads entering coastal waters due to fish farms was not accompanied by an increase in phytoplankton blooms, either of benign or harmful species. Smyada went on to conclude that: 40.1 “There is no evidence of a significant increase in nutrient levels, altered phytoplankton behaviour or an increase in harmful algal blooms in Scottish waters.” 40.2 “Blooms of harmful species present in Scottish waters are not dependent on aquacultural stimulation; all harmful species bloom in habitats not influenced by fish farm wastes.” 40.3 “..the observed phytoplankton behaviour in Scottish coastal waters does not appear to differ significantly from the natural and variable behaviour expected of an indigenous phytoplankton flora exposed to the ‘open system’ features of boreal waters.” Chile 41 Despite problems in recent years with a viral disease (Infectious Salmon Anaemia) the Chilean salmon industry remains the 2nd largest in the world. In 2010 between 250,000 and 300,000 tonnes were harvested, down from 400,000 tonnes in 2009 and a peak of 650,000 tonnes in 2008. The potential induction of HABs as a result of salmon aquaculture is a Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 23 of 41 major concern in Chile where highly toxic dinoflagellate blooms (especially of Alexandrium catenella) are common in the extensive areas of enclosed waters in the south of the country. A laboratory study (Arzul et al., 200134) showed salmon excretion products had no effect on the growth of toxic Alexandrium species, although Buschmann et al. (2006)35 found dinoflagellate growth was stimulated and diatom growth inhibited when fish farm effluents were used to fertilise large volume tanks. A limited field study showed that in the presence of salmon pens, significant increases in dinoflagellate densities occurred in pulses (Vegara, 200136). A. catenella has been associated with mass mortalities of salmon (>1,800 tonnes) on salmon farms in southern Chile (Fuentes et al., 200837). 42 Buschmann et al. (2007)38, in a major study of the nutrient impacts of farmed Atlantic Salmon on the pelagic ecosystem in Chile, stated that “there is little scientific evidence that nutrient loading from salmon farms is sufficient to initiate and sustain harmful algal blooms…”, though they acknowledged that “… nearly all the rigorous pelagic ecosystem science related to HABs has occurred outside the areas directly influenced by salmon farms”. They recommended that further field studies are needed “to answer concerns that elevated nutrients within densely-crowded salmon farming areas with limited flushing can promote the establishment of new harmful algal bloom seed areas.” 34 Arzul, G., Seguel, M., Clement, A. 2001.Effect of marine animal excretions on differential growth of phytoplankton species. ICES Journal of Marine Science58: 386-390. 35 Buschmann, A.H., Riquelme, V. A., Hernandez-Gonzalez, M. C., Varela, D., Jimenez, J.E., Henriquez, L. A., Vergara, P. A., Guinez, R., Filun, L. 2006. A review of the impacts of salmonid farming on marine coastal ecosystems in the southeast Pacific. ICES Journal of Marine Science 63: 1338-1345. 36 Vegara, P. 2001. Efectosambientales de la salmonicultura: El caso de Bahia Metri, Chile {in Spanish]. Master thesis, Universidad de Los Lagos, Osorno, Chile, 188pp. (Quoted by Buschmann et al., 2007). 37 Fuentes, C., Clement, A., Aguilera, A 2008. Summer Alexandrium catenella bloom and the impact on fish farming in the XI Aysen region, Chile. Moestrup, O. et al., [Eds] 12th International Conference on Harmful Algae, Copenhagen, Denmark 4-8 Sept 2006. I.O.C. UNESCO Pub.p.183186. 38 Buschmann, A.H., Costa-Pierce, B. A., Cross, S., Iriarte, J. L., Olsen, Y., Reid, G. 2007. Nutrient impacts of framed Atlantic salmon (Salmosalar) on pelagic ecosystems and implications for carrying capacity. Report of the Technical Working group (TWG) on Nutrients and Carrying Capacity of the Salmon Aquaculture Dialogue.30 August 2007, 68pp. http://www.worldwildlife.org/what/globalmarkets/aquaculture/WWFBinaryitem8844.pdf Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 24 of 41 Korea 43 Some HAB species have caused long term problems for aquaculture in Korean waters (Kim et al., 2010a39). The dinoflagellate Cochlodinium polykrikoides was for many years a persistent bloom former that severely impacted fish farms in enclosed or semi enclosed embayments in South Eastern Korea. It caused massive fish kills and economic losses of more than $100 million in the 1990s: Kudela & Gobler 201240).This species went from being a minor to a major component of the phytoplankton for about a decade before disappearing again. In Korea and other regions where C. polykrikoides blooms have caused major problems, blooms generally originate offshore as the result of large scale oceanographic processes and there is no strong evidence that implicates coastal eutrophication in their origin and development (Kudela et al., 200841). However, there is evidence that their growth is stimulated when offshore blooms intrude into areas where freshwater inflows and intensive fish or shrimp farming has caused localised coastal water enrichment and eutrophication (Ahn et al., 200642, Kim et al., 2010b43). USA and Canada 44 Since at least the 1980s there have been chronic problems with algal blooms causing finfish mortalities in the northeast Pacific regions of Canada and the United States. One species in particular (Heterosigma akashiwo) is notorious for its effects on fish farms in the region. The northwest coast of North America is characterised by regions of intense 39 Kim, H-G 2010a.An Overview on the Occurrences of Harmful Algal Blooms (HABs) and Mitigation Strategies in Korean Coastal Waters. In: Ishimatsu, A., Lie, H-J. [Eds] Coastal Environmental and Ecosystem Issues of the east China Sea. Pub. TERRAPUB and Nagasaki University pp. 121-131. 40 Kudela, R.M., Gobler, C.J. 2012. Harmful dinoflagellate blooms caused by Cochodinium sp. Global expansion and ecological strategies facilitating bloom formation. Harmful Algae 14: 71-86. 41 Philippine Journal of Science. 139(2): 139-147. Kudela, R.M., Ryan, J.P., Blakely, M.D., Lane, J.Q., Peterson, T.D. 2008. Linking the physiology and ecology of Cochlodinium to better understand harmful algal bloom events: A comparative approach. Harmful Algae 7: 278-292. 42 Ahn, Y-H., Shanmugam, P., Ryu, J-H., Jeong, J-C. 2006. Satellite detection of harmful algal bloom occurrences in Korean waters. 5: 213-231. 43 Kim, C-H., Park, T-G., Lee, C. 2010b.Harmful dinoflagellates and mitigation strategies in Korea.Philippine Journal of Science. 139(2): 139-147. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 25 of 41 upwelling and in the enclosed waters of Puget Sound and adjacent areas light, not nutrient supply, generally limits phytoplankton production. 45 Rensel (2007)44 in a review of the ecology and impacts of H. akashiwo blooms in Puget Sound states: “It is evident that fish farms do not cause Heterosigma akashiwo blooms in marine waters of Western Washington and the data suggest that it is unlikely they exacerbate booms.” The blooms generally arise in areas remote from fish farms from where they are transported by tides, winds and estuarine circulation processes. Blooms of H. akashiwo were recorded in the region well before any fish farms were established. In Washington State fish farms are required to be located in regions of naturally high dissolved inorganic nitrogen levels (Newton et al., 200245) and they make a very small contribution to the natural nitrogen loads carried by the waters in these regions. Discharge from major river systems play an important role in the establishment of a vertically stratified water column favourable to the development of blooms and their distribution by estuarine circulation. Heterosigma akashiwo blooms are typically late spring events coinciding with periods of warm weather and strong basin-wide water column stratification. Japan 46 In the 1950-1960s algal bloom outbreaks frequently caused mass mortalities of marine fauna in the Seto Inland Sea, associated with industrial and urban development and eutrophication of coastal waters (Okaichi, 199746). This eutrophication was largely due to inputs of N and P from industrial (2,200 manufacturing plants) and domestic sources (30 million population), although the rapid development of sea cage finfish 44 Rensel, J. E. 2007. Fish kills from the harmful alga Heterosigmaakashiwo in Puget Sound: Recent blooms and review. A technical report Sponsored by the National Oceanic and atmosphere administration; Centre for Sponsored Coastal Ocean Research 58pp. 45 Newton, J.A, Alberton, S.L., Van Voorhis, K., Maloy, C., Siegel, E. 2002. Washington State Marine Water Quality, 1998 through 2000. Washington State Department of Ecology Publication No. 0202-056. 46 Okaichi, T. 1997. Red tides in the Seto Inland Sea. In Okaichi, T. and Yanagi, T. [Eds] Sustainable Development in the Seto Inland Sea Japan from a fisheries point of view.Terra Scientific Publishing Company, Tokyo.329 pp. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 26 of 41 aquaculture at this time was also suspected to be a contributing factor. The main micro-algae species involved in these blooms were the raphidophyte, Chattonella antiqua which appeared in 1969 and the dinoflagellate, Gymnodinum mikimotoi which was mainly involved in the 1990s (Imai et al., 2006)47. Extreme blooms in 1972 caused mass mortality of approximately 14 million cultured yellowtail. This resulted in aquaculturalists taking lawsuits against cities and industries for compensation. As a result, the Japanese authorities instituted the Seto Inland Sea Law that established environmental water quality standards specifying acceptable N and P levels in seawater (0.2-0.6 mg/l and 0.020.05 mg/l respectively), measures to reduce the N and P levels in urban and industrial effluents and controls on reclamation projects. After the imposition of these controls the numbers and intensity of “red tides” decreased rapidly. Ironically, as the waters became less eutrophic a shift in community composition occurred, resulting in a greater incidence of species responsible for shellfish poisoning. In this case effluent controls reduced the number of ‘red-tide’ blooms but did not result in fewer HAB impacts (Anderson et al., 200248). Scandinavia 47 Toxic and noxious algal blooms affecting aquaculture are a frequent problem in the coastal waters of Norway and Sweden, although the species responsible for these effects have changed over time. In the 1960s dinoflagellate blooms (Gymnodinium aureolum, Prorocentrum minutum) caused fish kills and shellfish toxicity. In the 1980s there were a series of blooms of the haptophyte, Chrysochromulina polylepis that had a large impact on the sea cage salmon farming industry in the southern Skagerrak-Kattegat region (Graneli et al., 1993)49. 47 The cause of the Imai, I., Yamaguchi, M., Hori, Y. 2006.Eutrophication and occurrences of harmful algal blooms in the Seto Inland Sea. Plankton and Benthos Research 1(2): 71-84. 48 Anderson, D.M., Glibert, P.M., Burkholder, J.M. 2002. Harmful Algal Blooms and Eutrophication: Nutrient Sources, Composition and Consequences. Estuaries 25 (4b): 704-726. 49 Graneli, E., Paasche, E. Maestrini, S. 1993. Three years after the Chrysochromulinapolylepis bloom in Scandinavian waters in 1988: Some conclusions of recent research and monitoring. In Smayda T.J. and Shimizu, Y. [Eds] Toxic phytoplankton Blooms in the Sea. Elsevier p23-32. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 27 of 41 unusually extensive and intense blooms of C. polylepis was attributed to oceanographic processes that lead to the introduction of nitrate enriched waters into the Kattegat from the Baltic Sea and from eutrophic waters within the German Bight. It was found that low salinities reduced the toxic effect of the algae on fish, so sea- cages were towed from bloom exposed coastal areas into brackish waters of the inner parts of the fjords to mitigate their effect. In April-May 1998 a mass occurrence of Chattonella (now Pseudochattonella) verruculosa caused significant mortalities in salmon sea cages along the southwest coast of Norway and mass mortalities of wild fish populations on the west coast of Demark. The introduction of waters rich in nitrate (and with abnormally high N:P ratios) from the southern North Sea were considered to be a primary cause of the high phytoplankton biomass that became established in the region at the time (Aureet al. 200150). These nutrients were believed to be largely anthropogenic in origin originating from continental river discharges into the German Bight. 48 In 2011 a risk assessment report was made of the environmental impacts of Norwegian aquaculture (Taranger et al., 201151). This report focused on disease dispersal, genetic impact of escapees and the release of nutrient salts, organic waste and drugs. It did not mention the issue of HABs although it made reference to the impact on phytoplankton in general. The Norwegian fin-fish culture industry has an annual production of about 950,000 tonnes per annum distributed at many locations on a very long (approximately 1,900 miles) coastline. The total annual discharge of dissolved nutrients from this level of production is estimated to be approximately 9,800 tonnes of nitrogen and 1,600 tonnes of phosphorus. Acknowledging that the effect of nutrient additions depend on the sea surface area, residence time and current regime in the different growing areas, the authors reached the conclusion that the risk of regional 50 Aure, J., Danielssen, D.S., Skogen, M., Svendsen, E., Soland, H., Pettersson, L. 2001. Environmental conditions during the Chattonella bloom in the North Sea and Skagerrak in May 1998. In Harmful Algal Blooms 2000 Hallegraeff et al., [Eds] IOC UNESCO Pub. p82-85. 51 Taranger, G.L., Boxaspen, K.K., Madhun, A.S., Svasand, T. [Eds] Risk assessment-environmental impacts of Norwegian aquaculture. A report by the Institute of Marine Research, Norway August 2011. 48 pp. http://www.imr.no/filarkiv/2011/08/risk_assessment_engelsk_versjon.pdf/en Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 28 of 41 eutrophication in all areas was low although they could not rule out local impacts when fish farms were located in areas with poor water exchange. The report suggested that on-going monitoring and water quality assessments would provide better knowledge of areas that may be at risk of eutrophication. Baltic Sea 49 A study of the environmental effects of fish farm effluents in the Gulf of Bothnia (Baltic Sea off Finland) mainly found significant effects on nutrient enrichment (especially elevated levels of dissolved phosphorus) and phytoplankton standing crop in small (0.5-0.7 km2) shallow (3-4 m depth) embayments with water retention times of 2-6days supporting production of about 70 tonnes per year (Nordvarg & Johansson, 200252). One larger deeper embayment (8km2, mean depth 6 m) with a water retention time of eight days, which contains a large fish farm producing over 800-1000 tonnes per year, also had some evidence of nutrient enrichment and elevated phytoplankton biomass. A SUMMARY OF THE OVERSEAS EVIDENCE LINKING HARMFUL ALGAL BLOOMS AND SEA CAGE FISH FARMING 50 Concerns regarding sea cage fish farming frequently refer to the potential for coastal eutrophication and stimulation of HABs as a high risk factor. However, my search of the international literature does not reveal a strong relationship between HABs and fish farming, except in the most confined, poorly flushed and grossly polluted situations where the nutrient loads from the farms far exceed the assimilative capacity of the water body (e.g. Romdhane et al., 199853). There is scant evidence that chlorophyll a concentrations (i.e. phytoplankton biomass) are enhanced by nutrient 52 Nordvarg, L., Johansson, T. 2002. The effects of fish farm effluents on the water quality in the Åland archipelago, Baltic Sea. Aquaculture Engineering 25: 253-279. 53 Romdhane, M.S., Eilertsen, H.C., Yahia O.K.D., Yahia, M.N.D. 1998. Toxic dinoflagellate blooms in Tunisian lagoons: cause and consequences for aquaculture. In: Reguera et al., [Eds] Harmful Algae IOC UNESCO. p.80-83. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 29 of 41 inputs from fish farm cages (Beveridge et al., 199454; Pitta et al., 199955; Wu et al., 199456), even when these farms are in enclosed inland locations with restricted water exchange (e.g. Navarro et al., 200857). Most usually it seems that the fish farm operations encounter other water quality and health problems associated with overstocking (disease, parasites, sulphides, de-oxygenation etc.) before HABs become a major issue. Most, if not all, major HAB events that result in shellfish toxin problems and/or mass mortalities of wild or cultivated marine species are entirely natural. POTENTIAL EFFECTS OF FISH FARM EFFLUENTS WITH RESPECT TO HARMFUL ALGAL BLOOMS IN THE MARLBOROUGH SOUNDS 51 In the preceding evidence I have presented material that shows that there is a documented history of many types of naturally occurring HABs in New Zealand’s coastal waters. I have discussed the phytoplankton ecology of the Marlborough Sounds in the context of the physical and nutrient chemistry environment, and reviewed the international literature for evidence of an association between fish farming and HABs. In the following section I will discuss ways in which fish farm effluents could potentially increase problems with HABs. I will explain why, in the light of the present state of our knowledge of the Marlborough Sounds water column, and the history of salmon farming in New Zealand to date I believe these effects will be no more than minor. 52 Potential effects of the salmon farm effluent discharges include: 54 Beveridge, M.C.M., Ross, L.G., Kelly. L.A. 1994. Aquaculture and Biodiversity.Ambio 23: 497-502. Pitta, P., Karakassis, I., Tsapakis, M., Zivanovic, S. 1999. Natural vsmariculture induced variability in nutrients and plankton in the eastern Mediterranean. Hydrobiologia 391: 181-194. 56 Wu R.S.S. Lam, K.S., Mackay, D.W., Lau, T.C., Yam, V. 1994. Impact of marine fish farming on water quality and bottom sediment: A case study in the sub-tropical environment. Marine Environ. Res. 38: 115-145. 57 Navarro, N., Leakey, R.J.G., Black, K.D. 2008. Effect of salmon cage aquaculture on the pelagic environment of temperate coastal waters: seasonal changes in nutrient and microbial community. Marine Ecology Progress Series. 361: 47-58. 55 Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 30 of 41 52.1 Increases of growth limiting nutrients entering the Marlborough Sounds may lead to an elevated phytoplankton biomass and encourage a greater incidence of HABs; 52.2 These nutrient inputs will be at their maximum during summer when the upper water column is often substantially deleted of nutrients and when flagellate dominated phytoplankton communities are most common; 52.3 These nutrients are “unbalanced” in that they are rich in N and P but do not contain the silica essential for diatom growth, and hence are potentially preferential for the growth of harmful flagellates. 53 These potential effects are dealt with in the discussion that follows. The focus of this discussion is on the inputs of combined nitrogen to the system as this is generally acknowledged as the major limiting nutrient in coastal marine ecosystems, including the Marlborough Sounds58. 54 The increases in nitrogen concentrations and their dispersion from the proposed farm sites has been modelled, and is presented in the evidence of Mr Ben Knight. Biological processes are not factored into these models. For over a decade a large, multi-million dollar, interdisciplinary programme run by the Woods Hole Oceanographic Institute has been in progress on the east coast of the USA (Gulf of Maine) to develop a bloom simulation model of the toxic dinoflagellate Alexandrium fundyense (Anderson et al. 201059). This has to date been the only serious attempt to develop a numerical model to provide seasonal forecasts of any type of HAB anywhere. The simulation model has shown some promise but is far from infallible and is specifically applicable only to the Gulf of Maine. To simulate the effect of the salmon farm effluents using a biophysical phytoplankton productivity and community composition model that would be able to predict the probability of an increase in HABs in the 58 Gibbs, N., Ross, A., Downes, M. 2002. Nutrient cycling and fluxes in Beatrix Bay, Pelorus Sound, New Zealand. New Zealand Journal of Marine and Freshwater research 36: 675-697. 59 Anderson, et al. 2010. Bloom dynamics of the red tide dinoflagellate Alexandrium fundyense in the Gulf of Maine a synthesis and progress towards a forecasting capability. IECES CM 201/N:01. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 31 of 41 Marlborough Sounds, would be an extremely large, expensive and difficult task, if it was possible at all. It is doubtful that it would result in predictions that are any better than that which can be achieved by deduction from existing data and experience. 55 An important mitigating factor is that the sites selected for the proposed farms are all in areas of naturally high ambient levels of inorganic nutrients (especially nitrate) as they are close to regions which frequently experience oceanic upwelling of deep nutrient-enriched waters. Recent analyses of seawater in Queen Charlotte Sound by the Marlborough District Council clearly show the importance of Tory Chanel as a source of oceanic nutrients for the sound (Table 1, Figure 3). The concentrations of inorganic nitrogen (mainly nitrate-N) in Tory Channel are always high (approximately 6mmol-N m-3 = 84 mg-N m-3) in surface waters (Figure 3A), even in midsummer when the levels in euphotic waters around the rest of the sound are depleted. 56 Similarly, as referred to earlier in this evidence, upwelling of nutrient enriched waters is known to take place in mid-summer at the entrance to Pelorus Sound and elsewhere along the outer coast of the Marlborough Sounds (Figure 2). These upwelling phenomena have been associated with northwest winds resulting from a negative phase of ENSO (Zeldis et al., 200860). However other field and satellite observations of sea surface temperature (MacKenzie unpub.) clearly show that upwelling also occurs under positive phase (La Nina) conditions and the frequency and mechanism of these events has yet to be properly identified. 57 Although high levels of nutrient loading may be associated with increases in phytoplankton biomass, it is not the case that this necessarily results in an increase in the incidence of HABs. Two examples in New Zealand where this is demonstrated is the Firth of Thames and Big Glory Bay, Stewart Island. 60 Zeldis, J.R., Howard-Williams, C., Carter, C.M., Schiel, D.R. 2008. ENSO and riverine control of nutrient loading phytoplankton biomass and mussel aquaculture yield in Pelorus Sound, New Zealand. Marine Ecology Progress Series 371: 131-142. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 32 of 41 58 The Firth of Thames is a shallow body of water that receives high nitrogen loads (~ 5,000 tonnes N yr-1) from the rivers draining an intensively farmed catchment (Zeldis et al., 201061). River inflow contributes up to 70% of the dissolved inorganic nitrogen load 62 but it is estimated that denitrification removes a very large amount (~10,800 tonnes N y-1) of fixed nitrogen from the system in the form of nitrogen gas. Weekly phytoplankton monitoring has been in place in the Coromandel area adjacent to the Firth of Thames since 1993. Although HAB blooms have been detected from time to time they are not a major problem in this area. The most notable HAB blooms (MacKenzie et al., 199563) have been large scale events associated with upwelling over the Hauraki Gulf shelf break (Sharples & Grieg 199864). 59 Salmon farming has been in progress in Big Glory Bay since the early 1980s. Big Glory is a small (11.9 km2; mean depth~20 m), enclosed embayment with poor flushing characteristics (10-14 days water exchange). As referred to earlier in this evidence, in 1989 a bloom of Heterosigma akashiwo had a catastrophic effect on the farms and a large amount of stock (~600 tonnes) was lost within a few days. At the time annual production in the bay was around 1500 tonnes with an annual soluble nitrogen load of around 200 tonnes (Pridmore & Rutherford 199265). The effect of the salmon farms were estimated to have increased the mean nitrogen content by about 30%, however it was believed that the nitrogen concentrations in the bay were more likely controlled by the concentrations in the adjoining much larger embayment of Paterson Inlet, which in turn was subject to oceanographic upwelling processes. 61 Zeldis, J., Broekhuizen, N., Forsythe, A., Morrisey, D., Stenton-Dozey, J. 2010. Waikato Marine Finfish Farming: Production and Ecological Guidance. A report prepared for MFish Aquaculture Unit. NIWA Client Report CHC2010-147. 111p. 62 Zeldis, J. 2008. Exploring the carrying capacity of the Firth of Thames for finfish farming: a nitrogen mass-balance approach. A report for Environment Waikato. NIWA Client Report CHC2008-02. 28pp. 63 MacKenzie A. L., L. L. Rhodes, D. Till, F. H. Hoe Chang, H. Kaspar, A. Haywood, J. Kapa and B. Walker 1995: A Gymnodinium sp. bloom and the contamination of shellfish with lipid soluble toxins in New Zealand, Jan - April 1993. In P. Lassus, E. Erard, P. Gentien and C. Marcaillou [Eds] Harmful Marine Algal Blooms Lavoisier Science Publishers, Paris pp. 795-800. 64 Sharples, J. Grieg, M.J.N. 1998. Tidal currents, mean flows and upwelling on the north-east shelf of New Zealand. New Zealand Journal of Marine and Freshwater Research 32: 215-231. 65 Pridmore R.D., and Rutherford, J.C. 1992. Modelling phytoplankton abundance in a small enclosed bay used for salmon farming. Aquaculture and Fisheries Management. 23: 525-542. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 33 of 41 60 As a result of the 1989 bloom, weekly phytoplankton monitoring was initiated to provide an early warning of a repeat of this bloom. This monitoring continues to the present day and is now in its 23rd year. Throughout this time there has been no algal bloom which has caused significant mortalities although salmon farming has continued in the bay, to a current production of about 3000 tonnes per year. The nitrogen loads in Big Glory Bay relative to the volume and exchange velocity of the receiving waters are far in excess of those of the proposed Marlborough Sounds sites. 61 Because of the size and economic importance of the aquaculture industry, the Marlborough Sounds is the most intensively monitored region in New Zealand for HAB activity. The Marlborough Shellfish Quality Programme (MSQP) samples the water column and shellfish for phytoplankton and shellfish toxin analysis from 17 sites every week. This monitoring has been in progress continuously since 1993. A number of MSQP’s routine sampling sites are near NZKS’s existing farms in Pelorus and Queen Charlotte Sounds. In addition the company itself has carried out routine phytoplankton monitoring at the farm sites since their establishment, to provide an early warning of blooms that may affect their fish. From this monitoring there is a very large body of data on the occurrence of HAB species in the Sounds. There is no indication from the phytoplankton or biotoxin data of unusual HAB activity associated with the farms (Hopkins et al., 200466) and in fact many HAB events have been at locations far removed from them. 62 There have been two recent HAB events in Queen Charlotte Sound that have had important economic consequences. These have been referred to earlier in this evidence. The bloom of Pseudchattonella verruculosa that caused fish kills on the Ruakaka Bay farm in June 2010 is believed to have originated in the inland reaches of the Grove Arm and throughout its 66 Hopkins, G., Forrest, B., Clarke, M. 2004. Environmental Impacts of the Otanerau Bay Salmon Farm, Marlborough Sounds. A report for The New Zealand King Salmon Co. Ltd. Cawthron Report No. 824. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 34 of 41 duration remained confined to the inner sound67. The bloom was associated with the shoaling of high salinity water containing high levels of nitrate in inner Grove Arm. The mechanism of this upwelling is not known for sure but may relate to a period of high rainfall that set up an estuarine circulation pattern in the inner sound. 63 The bloom of the toxic dinoflagellate, Alexandrium catenella that caused lengthy closures of shellfish harvesting in the sound in 2011, almost certainly had its origin in Opua Bay, an enclosed, isolated bay off Tory channel68. Investigations over the last year have confirmed that Opua Bay has a resident population of the dinoflagellate that blooms in late summer, and analysis of cyst populations in sediment cores suggests that this population has existed for at least several decades. Opua Bay frequently supports a high phytoplankton biomass and is apparently fertilised by the intrusion of nutrient rich bottom water from Toy Channel, possibly under the influence of south easterly winds. There is a concern that A. catenella is in the process of expanding its range throughout the Sounds and its ecology is the subject of on-going research. 64 The two bloom events discussed above were driven by identifiable, natural, nutrient enrichment processes and are illustrative of the preferred flagellate habitats (especially dinoflagellate) of inner Queen Charlotte Sound and the bays off Tory Channel. These blooms developed due to the physical and biological nature of these environments (well stratified, weak current flows, long residence times, established populations) in combination with the abundance and quality of the inorganic nutrients in the oceanic waters from Cook Strait that fertilise these areas. 67 MacKenzie, L., Smith, K. F., Rhodes, L. L., Brown, A., Langi, V., Lovell, G., Preece, M. 2011a. Mortalities of sea-cage salmon (Oncorhynchustshawytscha) due to a bloom of Pseudochattonellaverruculosa (Dictyophyceae) in Queen Charlotte Sound, New Zealand. Harmful Algae 11: 45-53. 68 MacKenzie, L., Harwood, T., Boundy, M., Smith, K, Knight, B., Jiang, Weimin, McNabb, P., Selwood, A., van Ginkel, R., Langi, V., Edgar, M., Moisan, C. 2011b. An Alexandrium catenella bloom and associated saxitoxin contamination of shellfish, Queen Charlotte Sound, March-June 2011. A report for MAF Food Safety. Cawthron Report No. 1945. 38pp. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 35 of 41 Table 1. Seasonal and depth averaged dissolved inorganic nutrient concentrations and ratios in Marlborough Sounds and adjacent coastal waters. DRSi (dissolved reactive silicates); DIN (dissolved inorganic nitrogen); DRP (dissolved reactive phosphorus). DRSi Tasman Bay Water column DIN DRP mmol m-3 5.3 1.4 0.4 Wedge Pt. QC Sound. Water column 5.2 4.3 0.7 8:6:1 Pelorus Sound/Tennyson Inlet Water column 15.4 2.8 0.5 30 : 6 : 1 Tory Channel QC Sound* Surface Deep nd nd 6.0 5.2 0.4 0.4 nd : 15 : 1 nd : 13 : 1 **Redfield ratio DRSi:DIN:DRP 13 : 3 : 1 15 : 16 : 1 nd = not determined *Data courtesy of the Marlborough District Council **The Redfield ratio (Si:N:P = 15:16:1) is the optimum ratio of inorganic macro-nutrients for phytoplankton growth. This ratio is a constant in deep ocean waters throughout the world. Deviations from this ratio in euphotic waters indicate potential growth limitation though lack of an essential nutrient. For example a ratio of 30:6:1 (Pelorus Sound) shows that there is an excess of Si relative to P but N concentrations will probably limit phytoplankton growth. 65 Most streams and rivers naturally carry high loads of dissolved silica, which is an essential nutrient for the growth of diatoms. It is likely that an important factor in the propensity for Queen Charlotte Sound to experience a greater incidence of flagellate blooms than Pelorus Sound relates to the oceanic origin of the seawater and the relatively small amounts of freshwater that flow into it. As a consequence the salinity is high and quantities of dissolved silica that enter into the sound may become substantially exhausted after diatom blooms. This is shown by the low ratio of dissolved silica to N and P (compared with the Redfield ratio) in seawater within the Grove Arm (Wedge Point) of Queen Charlotte Sound and the high ratios found in Pelorus Sound seawater (Table 1.). Unfortunately there are no available silica analyses from Tory Channel but the oceanic origin of the water in this area is shown by the high N:P ratio that is close to the Redfield ratio. Although the salmon farm effluents are high in N and P but contain essentially no silica their input into the highly Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 36 of 41 dynamic, rapidly exchanging and nutrient rich environment of Tory Channel is unlikely to promote a nutrient imbalance within the Sound over and above that exists naturally. 66 An important feature of Pelorus Sound is the estuarine circulation pattern whereby low salinity surface waters from the inland reaches moves seaward to be replaced by deeper higher salinity ocean water from the outer region. This circulation transports lower salinity near-surface water as far as the outer Pelorus Sound/Waitata Reach region, carrying with it elevated concentrations of dissolved silica. In all areas of greater Pelorus and Kenepuru Sounds dissolved silica is usually present well in excess of the optimum requirements for diatom growth. The effluent discharges for the proposed farms into the Waitata reach are unlikely to be sufficient to make any detectable change in the ambient inorganic nutrient ratios and hence to the structure of phytoplankton communities. MONITORING RECOMMENDATIONS 67 Monitoring with regard to water column effects, including effects of nutrient loading on primary production (and potentially HABs) is covered by the evidence of Dr Paul Gillespie and includes a recommendation that NZ King Salmon contribute to and strengthen existing programmes (e.g. that of MSQP).aimed at monitoring and understanding HABs and water quality conditions in the Sounds SUBMISSIONS 68 I am aware that the NZ King Salmon application has attracted a large number of public submissions. While I have not read all of them, my attention has been drawn to a number of submissions (32) that are relevant to my area of expertise. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 37 of 41 69 Many of these submissions raise concerns about the general issue of the potential promotion of HABs due to fish farm effluents, for example: 69.1 “…increased risk of harmful fish toxic and/or shellfish toxic algal blooms (HABs).” (Submission 0061) 69.2 “The extra nutrients from fish waste may also increase the risk of poisonous algal bloom.” (Submission 0361) 69.3 “…the increased nutrient loading…increasing the potential for toxic and non-toxic algal blooms.” (Submission 0415) 69.4 “local mineral enrichment leading potentially to algal blooms” (Submission 0345) 69.5 “…increased nutrification….(and)….the effect this may have on increasing the frequency and length of toxic algal blooms…” (Submission 1000) 69.6 “Increased risk of algal blooms as a result of high nitrogen loading..” (Submission 1036) 69.7 And a number of other submissions containing similarly generic statements. 70 The issue of HABs in New Zealand in general and in the Marlborough Sounds in particular and the international evidence linking sea cage fish farming with HABs is covered in some detail throughout the body of my evidence. 71 Some submissions have raised specific issues which have been dealt with in the evidence but perhaps need more clarification here, I address these below: 71.1 Issue 1: The submission of Sustain our Sounds Inc. (EPA No. 0061) at paragraph 21 contains the statement: “The shellfish sampling programme results for the Marlborough Sounds Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 38 of 41 showing that the Ruakaka area (at least) is showing a lack of resilience and is susceptible to algal blooms.” This statement implies there is evidence that the Ruakaka farm has degraded water quality in this area which has led to an increase in HABs. In fact there is no evidence from the Marlborough Sounds Shellfish Quality Programme (MSQP) database or from the routine sampling that NZKS itself carries out that this is the case. In over 20 years of operation at this site we know of only one HAB event (the Pseudochattonella bloom in June 2010; Section 21.11 which has impacted the farm. There is good evidence that this bloom originated in the Grove Arm and was advected onto the farm. As has been discussed at some length in the my evidence (paragraphs 28-37) the inner part of Queen Charlotte Sound and the embayments off Tory Channel are naturally favourable flagellate habitats during the warmer months of the year and blooms are common in these areas. Ruakaka Bay is situated where inner sound, often strongly stratified water, meets well mixed more oceanic waters from Tory Channel and the outer sound and is influenced more or less by both at different times. 71.2 Issue 2: The submission of Lees (EPA No. 0602) contains the statement: “In Scotland algal blooms are a frequent result of untreated wastes from salmon farms; prior to the expansion of salmon farming in the 1980s there had been no incidence of toxic algal blooms in those areas.” As discussed in my evidence (paragraphs 39-41), Scotland is one of the few countries where there has been rigorous studies that have focussed on this question. These studies have failed to find any relationship between the incidence of HABs and sea cage fish farming. 71.3 Issue 3: Five of the submissions (EPA Nos. 0342, 0559, 0645, 0738 and 1053) make reference to the potential for the generation of blooms in enclosed or ‘blind’ bays. This is a legitimate concern because the weak current flows, long Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 39 of 41 retention time and strongly stratified water columns characteristics of these environments are preferred flagellate habitats. However this is precisely why NZKS has chosen sites on relatively open coastlines, exposed to high current flows of naturally nutrient replete waters so that nutrient enrichment of enclosed water bodies will be minimised. In the specific case of Deep Bay in Tory Channel (Submissions No.0342 and No. 0645) the water in the bay probably already has high levels of nitrate because of its close proximity to Tory Channel however the monitoring of enclosed embayments such as this in close proximity to the proposed farms should be a priority. 71.4 Issue 4: Two submissions (EPA No. 1072 and EPA No. 0111) raise the issue of a shift in phytoplankton species composition from diatom to dinoflagellate dominated communities as a result of increased nitrogen enrichment. I have dealt with this issue in my evidence (paragraphs 66-67) and I believe that within the context of the different nutrient chemistry conditions that prevail in Pelorus and Queen Charlotte Sounds it is unlikely to be important. In any case it is probably worth reiterating here that dinoflagellate dominated communities are natural and common in the Sounds. Dinoflagellates are an important component of the phytoplankton upon which most other marine life in the Sounds depend for their nutrition. CONCLUSIONS 72 The dynamics of algal blooms are determined by rapidly changing and complex interactions between physical, chemical and biological factors. We have a general understanding of how phytoplankton productivity is controlled by physical factors and seasonal and episodic nutrient supply in the Sounds. But except for few localities where resident populations of some species exist we cannot predict with any certainty (except by Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 40 of 41 monitoring) how selection processes will lead to the transient dominance of a ‘harmless’ species or one that has some property which puts it into the category of a ‘harmful algal bloom’. 73 HABs are relatively common in Queen Charlotte Sound but less so in Pelorus Sound, probably due to basic differences in the water chemistry of these regions. Seawater in Queen Charlotte Sound is oceanic in origin whereas seawater throughout much of Pelorus Sound is influenced by large freshwater inflows at the head of the sound and is more estuarine in character. Sheltered inlets with longer water retention times and stratified water columns in both Sounds are prime habitats for the establishment of flagellate dominated communities, including HAB species. 74 A thorough search of the international scientific literature did not provide evidence of a strong relationship between HABs and sea cage fish farming, except in the most confined, poorly flushed situations where the nutrient loads from the farms far exceed the assimilative capacity of the water body. 75 The fact that the nutrient inputs from the farms can be considered ‘unbalanced’ because of the lack of silica for diatom growth is not considered to be an important issue. Queen Charlotte Sound waters are probably naturally silica limited at times and the salmon farm effluents will not make a difference to the current situation. Whereas in Pelorus Sound silica is usually present in excess and so is unlikely to be limiting. 76 Effluents from the proposed sea cages will increase the nitrogen load on the system. However, these inputs need to be seen in the context of the ambient nutrient environment and the high rates of dilution, dispersion, assimilation and recycling that take place in the water column and sediments. The location of the farms in Tory Channel, Port Gore and outer Pelorus Sound where upwelling results in naturally high ambient nutrient levels, alleviates potential concerns that maximum rates of nutrient loading will take place in summer when the upper water column in the Sounds is generally nutrient depleted. Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012 Page 41 of 41 77 The proposed sites have been chosen to maximise the rapid dilution and dispersion of nutrients and minimise the potential for HAB development. The farms will be situated in deep, high current areas, with well mixed water columns and naturally high ambient inorganic nutrient concentrations. These conditions are not conducive to the development of flagellate dominated blooms. 78 It is not expected that the increase in nitrogen loads with their sources spread over a wide geographic area will lead to an increase in problems with HABs, or in fact, given the high natural variability, easily measurable increases in phytoplankton biomass (see evidence of Mr Ben Knight). The lack of evidence of an association between HABs and existing salmon farms in the Marlborough Sounds and Stewart Island suggests the effects of the proposed increased nutrient loads will be minimal. Name: Angus Lincoln MacKenzie Signature: Date: 21 June 2012 Statement Of Evidence In Relation To Water Column Effects: Harmful Algal Blooms Of Angus Lincoln MacKenzie For The New Zealand King Salmon Company Limited June 2012