COOK ISLANDS MARAE MOANA Marine Outlook Report 2020

Prepared by

Teina Rongo, Ph.D. Marine Biology

Teariki-Taoiau Rongo Jackalyn Rongo

COOK ISLANDS MARAE MOANA

Marine Outlook Report 2020

Disclaimer The authors have made reasonable efforts to ensure that the contents of this report are factually correct – borrowing the format of the well- established Great Barrier Reef Outlook Report, which Section 34 of the Cook Islands Marae Moana Act 2017 alludes to. However, the authors do not make any representation or give any warranty regarding the accuracy, completeness, currency or suitability for any particular purpose of the source material contained in this report. Readers should consult the source material referred to and, where necessary, seek appropriate advice about the suitability of the publication for their needs. The authors shall not be liable for any loss, damage, cost or expense that may be occasioned directly or indirectly through the use of or reliance on the contents of this publication.

How to cite this report Rongo, T.*, Rongo, T.T., Rongo, J. 2020. Cook Islands Marae Moana: Marine Outlook Report 2020. Government of the Cook Islands. 123 p.

*Corresponding author: PO Box 881, Avarua, Rarotonga, Cook Islands; [email protected]. 2

TABLE OF CONTENTS

LETTER OF TRANSMITTAL...... 7 ACKNOWLEDGEMENTS...... 8 EXECUTIVE SUMMARY...... 9

1. ABOUT THIS REPORT...... 10 1.1 Background ...... 10 1.2 Scope ...... 11 1.3 Methodology of assessment...... 13 1.3.1 Assessing values…………...... 13 1.3.2 Assessing trends………...... 14 1.3.3 Management of threats and risks...... 14 1.3.4 Evidence used…………………………...... 14

2. ECOSYSTEM HEALTH...... 15 2.1 Background ...... 15 2.2 Current condition and trends of physical processes ...... 16 2.2.1 Currents ...... 16 2.2.2 Cyclones and wind ...... ……………………………17 2.2.3 Freshwater inflow ...... ………………20 2.2.4 Sedimentation ...... 22 2.2.5 Sea level ...... 25 2.2.6 Sea temperature ...... 26 2.2.7 Light ...... 27 2.3 Current condition and trends of chemical processes ...... 28 2.3.1 Nutrient cycling...... 28 2.3.2 Ocean pH...... 29 2.3.3 Ocean salinity...... 30 2.4 Current condition and trends of ecological processes...... 31 2.4.1 Microbial processes ...... 31 2.4.2 Particle feeding...... 32 2.4.3 Primary production...... 32 2.4.4 Herbivory...... 34 2.4.5 Predation...... 35 2.4.6 Recruitment ...... 36 2.4.7 Connectivity...... 37 2.5 Current condition and trends in terrestrial habitats that support the islands of Marae Moana ...... 37 2.5.1 Saltmarshes ...... 37 2.5.2 Wetlands...... 38 2.5.3 Riparian zone………………………………………………………………………………………………………… 38 2.6 Current condition and trends of outbreaks of disease, pests and introduced species………………...... 39 2.6.1 Outbreaks of disease...... 39 2.6.2 Outbreaks of Crown-Of-Thorns starfish...... 40 2.6.3 Introduced species ...... 41 2.6.4 Other outbreaks...... 41 2.7 Assessment summary – Ecosystem health...... 42 2.7.1 Physical processes...... 42 2.7.2 Chemical processes ...... 42 2.7.3 Ecological processes ...... 42 2.7.4 Terrestrial habitats that support the islands of Marae Moana...... 42 2.7.5 Outbreaks of disease and introduced species...... 43 2.7.6 Overall summary of ecosystem health ...... 43

3. BIODIVERSITY………………………………………………………………...... 44 3.1 Background ...... 44 3.2 Legacies and shifted baselines ...... 44 3.3 Current condition and trends of habitats to support species...... 45 3.3.1 Land beaches and coastlines...... 45 3.3.2 Coral reefs ...... 45 3.3.3 Islands ...... 45

Northern Cook Islands 3.3.3.1 Manihiki...... 46 3.3.3.2 Rakahanga...... 47 3.3.3.3 Penrhyn...... 47 3.3.3.4 Pukapuka...... 48 3.3.3.5 Nassau...... 49 3.3.3.6 Suwarrow...... ,...... 50 Southern Cook Island 3.3.3.7 Rarotonga...... 51 3.3.3.8 Mangaia...... 53. 3.3.3.9 Aitutaki...... 54 3.3.3.10 Manuae...... 55 3.3.3.11 Takūtea...... 57 3.3.3.12 Atiu...... 59 3.3.3.13 Mitiaro...... 60 3.3.3.14 Ma’uke...... 62 3.3.3.15 Palmerston…...... 63 3.3.4 Mesophotic Coral Ecosystems...... 64. 3.4 Current condition and trends of populations of species and groups of species ...... 65 3.4.1 Macroalgae ...... 65 3.4.2 Benthic microalgae...... 66 3.4.3 Corals...... 66 3.4.4 Other invertebrates...... 66 3.4.4.1 Crabs………………………………………………………………………………………………… 66 3.4.5 Sharks and rays ...... 67 3.4.6 Marine turtles...... 68 3.4.7 Seabirds...... 68 3.4.8 Cetaceans...... 69. 3.5 Assessment summary – Biodiversity ...... 70 3.5.1 Habitats to support species ...... 70 3.5.2 Populations of species and groups of species ...... 70 3.5.3 Overall summary of biodiversity...... 70

4. HERITAGE VALUES...... 71 4.1 Background...... 71 4.2 Current state and trends of Indigenous heritage values...... 72 4.2.1 Cultural practices, observances, customs and lore ...... 72 4.2.2 Sacred sites, sites of particular significance and places important for cultural tradition…………………… 73 4.2.3 Stories, songlines, and languages...... 74 4.2.4 Indigenous structures, technology, tools and archaeology...... 75 4.3 Current state and trends of historic heritage values...... 76 4.3.1 Historic voyages and shipwrecks ...... 76 4.3.2 Other places of historic significance...... 76 4.4 Assessment summary — Heritage values ...... 77 4.7.1 Indigenous heritage values ...... 77 4.7.2 Historic heritage values ...... 77 4.7.3 Overall summary of heritage values ...... 77

5. COMMERCIAL AND NON-COMMERCIAL USE...... 78 5.1 Background ...... 78 5.2 Traditional use of marine resources ...... 78 5.2.1 Current state and trends of traditional use of marine resources……………………………………………… 80 5.2.2 Benefits of traditional use of marine resources...... 80 5.2.3 Impacts of commercial marine tourism...... 80 5.3 Commercial marine tourism ...... 81 5.3.1 Current state and trends of commercial marine tourism ...... 81 5.4 Fishing ...... 82 5.4.1 Current state and trends of fishing...... 82 5.4.1.1 Coastal fisheries & aquaculture…………………………………………………………………… 82 5.4.1.2 Offshore fisheries ……………………………………………………………………………………83 5.4.2 Benefits of fishing ...... 86 5.4.3 Impacts of fishing ...... 87

5.4.3.1 Bycatch...... 87 5.5 Recreation (not including fishing) ...... 87 5.5.1 Current state and trends of recreation...... 88 5.6 Shipping ...... 88 5.6.1 Current state and trends of shipping ...... 88 5.6.2 Benefits of shipping...... 89 5.6.3 Impacts of shipping ...... 89 5.7 Deep sea mining...…...... 90 5.7.1 Current state and trends of deep sea mining...... 90 5.7.2 Benefits of deep sea mining...... 90 5.7.3 Impacts of deep sea mining ...... 90 5.8 Assessment summary — Commercial and non-commercial use ...... 91 5.8.1 Economic and social benefits of use ...... 91 5.8.2 Impacts of use on the Region’s values ...... 91 5.8.3 Overall summary of commercial and non-commercial use...... 91

6. RISKS TO MARAE MOANA VALUES…………………...... 92 6.1 Identifying and assessing the threats...... 92 6.1.1 Identifying the threats...... 93 6.1.1.1. Coral bleaching………………………………………………………………………………………93 6.1.1.2 Marine disease…………………………………………………………………………………… 98 6.1.1.3. Ciguatera poisoning………………………………………………………………………………. 98 6.1.1.4 Watershed pollution………………………………………………………………………………..101 6.1.2 Assessing threats ...... 101 6.1.2.1. Coral bleaching……………………………………………………………………………………. 101 6.1.2.2 Marine disease…………………………………………………………………………………….. 102 6.1.2.2.1 Algal disease……………………………………………………………………….. 102 6.1.2.2.2 Pearl oyster disease…………………………………………………………………102 6.1.2.2.3 Urchin disease………………………………………………………………………..103 6.1.2.3. Ciguatera poisoning…………………………………………………………………………………104 6.1.2.4 Watershed pollution…………………………………………………………………………………105 6.1.3 Understanding community views...... 105 6.3 Assessment summary – Risks to the Region’s values ...... 105 6.3.1 Risks to the ecosystem ...... 105 6.3.2 Risks to heritage values ...... 106 6.3.3 Overall summary of risks to the Region’s values ...... 106

7. EXISTING PROTECTION AND MANAGEMENT………...... 107 7.1 Background ...... 107 7.1.1 Roles and responsibilities...... 107 7.1.2 Focus of management...... 108 7.1.3 Management approaches and tools ...... 108 7.2 Assessment of existing protection and management measures...... 108 Managing direct use ...... 108 7.2.1 Research activities...... 108 7.2.2 Traditional use of marine resources ...... 110 Managing external factors ...... 111 7.2.3 Climate change ...... 111 7.2.4 Coastal development...... 112 7.2.5 Land-based run-off...... 112 Managing to protect the Region’s values ...... 112 7.2.6 Biodiversity values ...... 112 7.3 Assessment summary — Existing protection and management ...... 113

8. FACTORS INFLUENCING MARAE MOANA VALUES...... 114 8.1 Background...... 114 8.2 Climate change ...... 114 9.3.1 Trends in climate change ...... 114 8.3 Coastal development ...... 115 8.3.1 Trends in coastal development ...... 115 8.4 Assessment summary – Factors influencing Marae Moana values ...... 116

9. LONG-TERM OUTLOOK...... 117 9.1 Background ...... 117 9.2 Knowledge for management ...... 117 9.2.1 Improved understanding ...... 118 9.2.2 Remaining information gaps ...... 118 9.3 Assessment summary – Long-term outlook ...... 118 9.3.1 Outlook for the Marae Moana’s ecosystem...... 118

REFERENCES...... 119

LETTER OF TRANSMITTAL

Hon. Minister Henry Puna Prime Minister Cook Islands Government

Marae Moana Council Cook Islands Government

Kia Orana Honourable Prime Minister Puna and Marae Moana Council members,

I am pleased to provide the Marae Moana Outlook Report 2020 to you as our country’s Prime Minister and Marae Moana Council members, and through you to the Cook Islands Parliament and the people of the Cook Islands.

The Marae Moana Outlook Report 2020 has been prepared by our local marine experts based on the best available information, and fulfilling the requirements of Section 34 of the Cook Islands Marae Moana Act 1975. It has not been without challenges for these small number of researchers to capture the plethora of information to produce our country’s first Marae Moana Outlook Report. Legislation calls for the Marae Moana Outlook Report to be reviewed every six years, and the 2nd report to be produced in 2026 should provide a follow-up to the initial outlooks provided in this report.

______Maria Tuoro Marae Moana Coordinator Office of the Prime Minister

ACKNOWLEDGEMENTS

The first Marae Moana Outlook Report was prepared by Rongo Consultants, a local team consisting of expertise in our country’s marine environment through years of observation and interaction. Information was supplied by associated Government Ministries of the Cook Islands and relevant stakeholders to build this report.

Meitaki Ma’ata to all who assisted and provided information in the development of this report.

EXECUTIVE SUMMARY

The outlook for the Marae Moana, is at a crossroad, and what the world and especially the Cook Islands Government decide in the next few years are likely to determine its long-term future. Indeed, the predictions of climate change paint a very bleak future for the most over the next few decades with thermal stress becoming more frequent, severe cyclone events, and increased disease prevalence on coral reefs, just to name two. Nevertheless, the persistence of these impacts will depend to a large degree on the direction desire that international community take to mitigate climate change. Despite limited information for the Cook Islands, anecdotal and local knowledge suggest that the state of marine ecosystem throughout the Cook Islands have declined, and will likely continue in this downward trajectory with continued increased of carbon dioxide concentration and sea surface temperatures. With these changes hard corals would likely become functionally extinct and coral reefs would be eroding rapidly. Although much considerations are implemented to improve the resilience of the Cook Islands’ marine ecosystem (e.g., establishment of a network of rā`ui by the traditional leaders), some national initiatives are worrying (e.g., ocean outfall options, deep sea mining) because of the risks. Therefore, the resilience will depend in large part on how effectively the risks of these initiative are managed. Variations in ecosystem response to the threats will differ depending on the proximity to concerned sites. Such differences are now observable and are likely to become more obvious over time if these risks are not managed accordingly. Generally, the areas at most significant risk are those closest to already developed areas that have already deteriorated more because of catchment runoff and coastal development. For some, threats related to climate change (e.g., coral bleaching in the northern group) these are predicted to worsen. Ultimately, if changes to the world’s climate become too severe, no management actions will be able to climate-proof these ecosystems in the Marae Moana.

1. ABOUT THIS REPORT

1.1 Background The Marae Moana Act 2017 passed by the Parliament of the Cook Islands in July 2017 created the largest multi-use (Figure 1) marine protected area in the world covering the country’s entire Exclusive Economic Zone (EEZ) of approximately two million square kilometres (Figure 2). The Cook Islands is made up of 15 islands with a land area of approximately 240 km2 and a reef area of approximately 667 km2 (Jonhson et al., 2016). Twelve islands in the Cook Islands are inhabited: Rarotonga, Mangaia, Aitutaki, Atiu, Mitiaro, Ma’uke, Palmerston, Pukapuka, Nassau, Manihiki, Rakahanga, and Penrhyn; the three uninhabited islands are Manuae and Takūtea in the southern Cook Islands, and Suwarrow in the northern Cook Islands. There are four island systems found in the Cook Islands; high island system (Rarotonga), atoll system (Manihiki, Rakahanga, Suwarrow, Penryhn, Pukapuka, Palmerston and Manuae), almost atoll system (Aitutaki), makatea island system (Atiu, Mitiaro, Ma’uke and Mangaia), and sand cays islands (Nassau and Takūtea). The main island is Rarotonga, and the rest of the islands are referred to as the Pa Enua (outer islands).

Figure 1. A multiple-use Marine Park concept for Marae Moana. Taken from an information sheet released in 2011 by the Office of the Prime Minister of the Cook Islands in collaboration with the House of Ariki, Park proponent Kevin Iro, Conservation International, and the Secretariat of the Pacific Regional Environment Programme (SPREP).

1.2. Scope

Section 34 of the Marae Moana Act 2017 requires the Marae Moana Outlook Report be prepared every 6 years. This report is the first Marae Moana Outlook Report and it describes and assesses the following, as required under Section 34 of the Act: . The current health of the ecosystems within the Marae Moana and of the ecosystems outside the Marae Moana to the extent that they affect the Marae Moana . The status of biodiversity within the Marae Moana . Commercial and non-commercial use of the Marae Moana . Risks to the ecosystems within the Marae Moana . The resilience of ecosystems within the Marae Moana . Existing measures in place to protect and manage ecosystems within the Marae Moana . Factors influencing the current and projected future environmental, economic, and social values of the Marae Moana . The long term outlook for ecosystems within the Marae Moana . Any other matter prescribed by regulations for the purpose of this section

The preparation of the Marae Moana Outlook Report will involve a desktop review and collating of existing reports, input from an organized peer review, and input from participants to the stakeholder’s workshop. This will provide the Cook Islands Marae Moana Council with the information needed upon which to base its decisions. This project is a part of the GEF-UNDP funded Ridge to Reef project administered by the Cook Islands National Environment Service and entitled “Conserving biodiversity and enhancing ecosystem functions through a ‘Ridge to Reef’ approach in the Cook Islands”. Specifically, this falls under Activity 1.3.6 of that project – “Strengthen Knowledge Management Systems for Ridge to Reef approaches and for Protected Areas”.

Figure 2. Left: Map of the Pacific with the location of the Cook Islands indicated in the boxed region. Right: the Cook Islands’ Exclusive Economic Zone in black outline, which encircles the red circles around each island indicating the 50-nautical-mile marine protected areas within Marae Moana; map provided by the Office of the Prime Minister of the Cook Islands.

1.3. Methodology of assessment

1.3.1. Assessing values

For each component, describe, using best available evidence, the state of the component.

 Provide long-term outlook of the Marae Moana biodiversity values.

Example 1: for biodiversity and ecosystems, define the component and use the following criteria and sub-criteria to assess. Criteria Sub-Criteria 1. State of habitat to support the species Factors influencing Resilience of Risks to Existing protection and management 2. Population of the species Factors influencing Resilience of Risks to Existing protection and management

 Provide long-term outlook of the Marae Moana heritage values.

Example 2: for heritage values, define the component and use the following criteria and sub-criteria to assess both tangible and intangible values. Criteria Sub-Criteria 1. Tangible and intangible values Factors influencing Resilience of Risks to Existing protection and management

 Provide long-term outlook of the Marae Moana commercial and non-commercial use values.

Example 3: for commercial and non-commercial use, define the component and use the following criteria and sub- criteria to assess. Criteria Sub-Criteria 1. Commercial use Factors influencing Resilience of Risks to Existing protection and management 2. Non-Commercial use Factors influencing Resilience of Risks to Existing protection and management

1.3.2. Assessing trends

Describe the trends for each component by comparing previous records to most current records. For biodiversity, ecosystem, commercial and non-commercial uses, there are four categories used here: . Improved. . Stable. . Deteriorated. . No consistent trend.

For no consistent trend, it is applied if the available information is too variable to establish a trend (e.g., where there is strong variation across broad areas or across species within a group in the case of biodiversity).

In the case of heritage values trends would be described as:

. No longer practiced or recognized. . At risk of being no longer practiced or recognized. . Still practiced, recognized and have a future in the long-term outlook as is or with some improvement.

1.3.3. Management of threats and risks

Based on the work of managing agencies, research individuals and institutions, traditional knowledge practitioners, topic experts and informed stakeholders, and from their past and present works, assessment of existing protection and management are provided to minimize the risks to the values described. In assessing the benefits, impacts, threats and risks, the terms ‘improved’ and ‘deteriorated’ are replaced with ‘increased’ and ‘decreased’. The information used in assessing components fall under the following categories: . Adequate high quality evidence and high level of consensus. . Limited evidence or limited consensus. . Inferred, very limited evidence.

1.3.4. Evidence used

The information in this report is only a portion of all that is known about Marae Moana. The evidence used is derived from existing research and information sources. It is drawn from best available published and unpublished information and based on the following:

. Relevance to the required assessments. . Duration of study. . Extent of area studied. . Reliability (such as consistency of results across different sources, peer-reviewed and rigor of study). 14

2. ECOSYSTEM HEALTH

2.1 Background The 15 islands of the Cook Islands are further referred to geographically as the following (Figure 3):

Northern Cook Islands or ‘northern group’  Suwarrow (uninhabited)  Nassau  Pukapuka  Manihiki  Rakahanga  Penrhyn

Southern Cook Islands or ‘southern group’  Rarotonga (main island)  Mangaia  Ma’uke  Atiu  Takūtea (uninhabited)  Mitiaro  Manuae (uninhabited)  Aitutaki  Palmerston

Figure 3. Map showing the 15 islands of the Cook Islands by their geographical reference, northern Cook Islands and southern Cook Islands. Rarotonga is the main island. Uninhabited islands are Suwarrow, Manuae, and Takūtea. Figure is not to scale. Source: http://www.vidiani.com/map-of-cook-islands/ 15

Table 1 is taken from the 5th National Report to the Convention on Biological Diversity (Butler, 2017), which summarizes the island by island review of the 4th National Report to the Convention on Biological Diversity (Passfield and Rongo, 2011), including land area, highest elevation, island type, terrestrial habitats, and inshore marine habitats.

Table 1. Information on the 15 islands of the Cook Islands, geographically referred to as the southern Cook Islands or ‘southern group’ and northern Cook Islands or ‘northern group’. Of note is all the atolls and sand-cays should be coconut forest with some broadleaf. Taken from Butler (2011) and Ponia (2000).

Island Land Area Highest Island type Terrestrial habitats Inshore marine habitats (km2) elevation (m)

Southern Group Rarotonga 67.4 652.0 Volcanic island Cloud, upland, lowland, & coastal forests, Fringing coral reef and shallow wetlands lagoon Mangaia 48.3 169.0 Raised limestone island Makatea forest, volcanic shrub, wetlands Fringing reef Ma’uke 19.1 29.0 Raised limestone island Makatea forest Fringing reef Atiu 26.9 72.0 Raised limestone island Makatea forest, volcanic shrub, wetlands Fringing reef Takūtea 1.0 5.0 Uninhabited sand cay Coconut forests & some broadleaf Fringing reef Mitiaro 22.3 15.0 Raised limestone island Makatea forest, lake Fringing reef Manuae 6.2 10.0 Uninhabited atoll Coconut forests & some broadleaf Fringing & barrier reefs, lagoon Aitutaki 18.0 124.0 Volcanic island/atoll Coconut forests, some broadleaf, & Lagoon, saltwater marshes, fringing wetlands reef Palmerston 2.1 5.3 Atoll Coconut forests & some broadleaf Lagoon, fringing reef Northern Group Suwarrow 0.4 3.0 Atoll Coconut forests & some broadleaf Lagoon Nassau 1.3 9.0 Sand cay Coconut forests & some broadleaf Barrier reef, deep lagoon Pukapuka 3.8 4.0 Atoll Coconut forests & some broadleaf Barrier reef, deep lagoon Manihiki 4.9 5.0 Atoll Coconut forests & some broadleaf Lagoon, brackish ponds Rakahanga 4.0 3.0 Atoll Coconut forests & some broadleaf Lagoon Penrhyn 10.0 3.0 Atoll Coconut forests & some broadleaf Lagoon

2.2 Current condition and trends of physical processes

2.2.1 Currents Ocean currents have many profound impacts on marine life, moving not only animals and plants around the ocean but also redistributing heat and nutrients. Surface ocean currents are critical for understanding the connectivity among islands and among reefs respectively. The Cook Islands is part of a Pacific wide ocean circulation system that interacts with atmospheric system (e.g., temperature and tradewinds) that influence the distribution of migratory species and larvae between regions, islands, and reefs. Currents are essential for the survivals of marine ecosystems of the world. However, very little is known about the regional current flows and especially with nearshore coastal environments in the Cook Islands. Treml et al (2008) indicated that a southwestward current from French Polynesia may facilitate larval supply to the Cook Islands during El Niño years. In addition, deep water currents also influence the distribution of deep water minerals and heat in the Pacific. In particular, the “thermohaline circulation” – also referred to as the meridional overturning circulation (MOC) that enters the Cook Islands from the south in a northward direction (Figure 4) – is an important deep water current that facilitates mineral formation in the region (Lusty and Murton, 2018). The Northward surface flow of the MOC transfers a substantial amount of heat energy from the tropics and Southern Hemisphere toward the North Atlantic.

Figure 4. Meridional Overturning Current (MOC). http://www.geologyin.com/2014/05/thermohaline- circulation-thc.html

2.2.2 Cyclones and wind Cyclones are very much part of living in the tropics. For centuries of experiencing and observing cyclones, Pacific people have learned to predict them and how to cope with their impacts, post cyclone. With a shift from simple living requirements to the westernized intricate infrastructure, we have also seen an increase in damage and economic loss due to cyclones in recent years. A report by the World Bank (2011), estimated an economic loss of $USD 5 million for the Cook Islands, following the six major cyclones in 2005. Cyclones also play an important role in determining the state of reefs. For example, De’ath et al. (2012) showed that from 1985 to 2012 using data from 2,258 surveys of 214 reefs in the Great Barrier Reef that cyclones contributed to 48% of coral loss. Rongo et al. (2009) suggested that the six major cyclones that passed in the region from 2004 and 2005 likely hindered the recovery of Rarotonga’s reefs, following the Crown-of-thorns Starfish (COTS) outbreak from 1995 to 2001. In addition, Rongo and van Woesik (2012) showed that higher frequency of cyclones was important to increasing the incidence of ciguatera poisoning on Rarotonga. Trade winds are also important and scientists have recorded an increased velocity of the easterlies within the last 20 years, which is expected to generate stronger and higher wind driven wave surges, which cause increase sediment transport, affect recruitment of marine organisms, and coastal erosion. In the Cook Islands, the position and intensity of the South Pacific Convergence Zone (SPCZ), an area of convergence between low-latitude easterly trade winds and the higher-latitude southeast trades, play an important role in cyclone formation during the months of November to April, the cyclone season for Niño 3.4 Region. Over a period of 186 years (1820 – 2006), cyclone frequency in the Cook Islands has seen an increase (de Scally, 2008; Figure 5 & 6), and the recurrence interval is higher in the southern group than the northern group (Table 2). The study also showed that Palmerston is the most visited by cyclones.

Figure 5. Generalized tracks of 104 cyclones in the Cook Islands, 1820–2006. The origin of cyclones tracking from west of 175ºW longitude is not shown, and many cyclones tracked east or south out of the map area before decaying or undergoing extratropical transition. Solid black line delineates the Exclusive Economic Zone of the Cook Islands. Figure taken from de Scally (2008).

Figure 6. Number of cyclones per season in the Cook Islands from 1820 to 2006. Taken from de Scally (2008).

Table 2. Cyclone occurrence from 1970 - 2006 for the Cook Islands as a whole and also by group. Taken from de Scally (2008).

Average Cyclones Area Total Cyclones per season (1970 - 2006) Recurrence Interval (yr) Cook Islands 65 1.8 0.6 Southern Groupa 58 1.6 0.6 Northern Groupa 25 0.7 1.4 Group unknown 0 – – Palmerston 25 0.7 1.4 a Each group’s tally includes cyclones that affected both groups.

The El Niño Southern Oscillation strongly influence cyclone occurrence in the region. de Scally (2008) showed that 56% of cyclones from 1970 to 2006 was reported during El Niño years, 34% during Neutral years, and 9% during La Niña years (Table 3). Considering that ENSO events can be predicted accurately three months prior, this information has been critical for preparation purposes during cyclone season.

Table 3. Cyclone occurrences during El Niño, La Niña, and Neutral ENSO Conditions as defined by SST anomalies in the Niño 3.4 Region. Taken from de Scally, 2008.

No. of cyclone occurrences (%) 1870 - 1969 1970 -2006 El Niño events 28 (41) 36 (56) Neutral conditions 29 (42) 22 (34) La Niña events 12 (17) 6 (9) Total number of cyclones 69 64

The low pressure area near the equator (10° N to 10°S) and an area of high pressure centred around the 30°S are impotant because the pressure gradient between two areas generate a wind that is referred to as the “trade winds”. The trade winds are an important feature for the region because it can influence the availability of rainfall, ocean and atmosperic temperaures, and the migration and recruitment of marine species. In the Cook Islands, trade winds are predominantly from the east with seasonal variations corresponding to tropical depressions or cyclones during summer and the wet season (Baldi et al., 2009). According to the IPCC report (2018) using emission scenarios of low (B1), medium (A1B) and high (A2) for the years 2030, 2055 and 2090, the Cook Islands can expect more severe cyclones with less frequency. Increase in average maximum wind speed between 2% and 11% will impact fragile infrastructure and various ecosystems in the Cook Islands.

2.2.3 Freshwater inflow The South Pacific Convergence Zone (SPCZ) is an important climatic feature not only in the Cook Islands, but also for the tropical southwest Pacific because it determines the long-term distribution of rainfall in this region. On average for the Cook Islands, the SPCZ lies to the west and south of the northern group, but north of the southern group stretching in a northwest to southeast orientation (Figure 7; see Cook Islands Meteorological Service et al., 2011). During the wet season (November to April), the SPCZ is active, bringing unsettled weather and rain over the Cook Islands. However, during the dry season (May to October), the SPCZ is weak and roughly lies to the north of the southern group bringing dry southeast trades winds over the group.

Figure 7. The average positions of the major climate features in November to April, including the South Pacific Convergence Zone. The arrows show near surface winds, the blue shading represents the bands of rainfall convergence zones, the dashed oval shows the West Pacific Warm Pool and H represents typical positions of moving high pressure systems. Taken from: Cook Islands Meteorological Service et al., 2011.

A slight displacement in the SPCZ location can cause drastic changes to hydroclimatic conditions and the frequency of extreme weather events in the region, and therefore understanding its behaviour has broad scientific and economic implications. The SPCZ position varies from its mean location with the El Niño Southern Oscillation (ENSO), moving a few degrees northward during moderate El Niño events and southward during La Niña events (Vincent, 1994; Folland et al., 2002; Vincent et al., 2011). During strong El Niño events, however, the SPCZ could undergo an extreme swing up to 10 degrees of latitude toward the Equator (Cai et al., 2012), bringing severe weather impacts to vulnerable small island nations in the region. At the decadal scale, Pacific-wide variability in climate that results in abrupt ‘shifts’ in climate patterns can persist for decades. The Interdecadal Pacific Oscillation (IPO; Latif et al., 1997; Folland et al., 1998; Zhang et al., 1997) and the Pacific Decadal Oscillation (PDO; Mantua et al., 1997) have been used interchangeably in the literature to describe these decadal oscillations, because they are highly correlated and equivalent in describing Pacific-wide variations in ocean climate (Power et al., 1999; Verdon & Franks, 2006); in this report, we used both IPO and PDO interchangeably as well to describe interdecadal climate variability in the Cook Islands region. At the inter-annual scale, the El Niño Southern Oscillation (ENSO), which has a similar effect as the decadal oscillations mentioned above but is more intense, operates at approximately two to seven years before phase shifts compared with the IPO and PDO that undergo phase shifts approximately every 15 – 30 years. Although the link between ENSO and PDO remains ambiguous, Verdon & Franks (2006) suggested a coupling effect in which El Niño events tend to be frequent during the positive PDO phase, and La Niña events frequent during the negative PDO phase. During the negative IPO/PDO phase and La Niña years, the southern Cook Islands experience warm and wet conditions, while the northern Cook Islands experience the opposite (Figure 8). On the contrary, the positive IPO/PDO phase and El Niño years tend to bring cool and dry conditions to the southern group, and warm and wet conditions to the northern group (see Figure 8).

Figure 8. Sea surface temperature anomalies in the Pacific with regards to the El Niño Southern Oscillation and the Pacific Decadal Oscillation. The black box indicates the southern Cook Islands region. Figure modified from http://jisao.washington.edu/.

2.2.4 Sedimentation Human impacts on adjacent land masses as well as in the marine environment have resulted in the widespread degradation of coral reefs and the loss of related resources (Richmond 1993; Pandolfi et al. 2003). Overfishing, mass bleaching events tied to global climate change and poor land-use practices in adjacent watersheds are among the greatest threats to reef ecosystems. There are two types of sediments that are important in the marine environment; 1) terrigenous, which are volcanic in origin, and 2) sand, which are eroded calcium carbonate from dead calcified organisms. Over the past several decades, substantial increases in terrigenous sedimentation have occurred from runoff into the marine environment in many areas of the Pacific Ocean (Birkeland 1977; Acevedo et al. 1988; Victor et al., 2006). Depending on the type of watershed alterations, rates of sedimentation from land erosion can increase by as much as 100-fold over natural levels (Doolette and Magrath 1990; Wolanski, et al. 2003). In the absence of human activities, natural levels of suspended sediments on reefs are usually < 5 mg/l and rarely exceed 40 mg/l (Larcombe et al. 1995; Kleypas 1996). During tidal changes and storms (both of which re-suspend sediments) or following periods of terrestrial runoff from heavy rains, suspended sediment levels can range from approximately 20 to 200 mg/l (Gilmour 1999). However, sedimentation levels that are the result of anthropogenic alterations often exceed 200 mg/l.

Wave action is a factor that causes sediments to be re-suspended. Waves can be put into two broad categories: swells, which are generated by tropical storms over greater distances and are generally large; and local wind-generated- waves, which are generally smaller. Understanding the wind conditions on certain coasts can give information on how waves are generated and how they might affect sediment re-suspension. Larcombe et al., (1995) examined the effects of waves on (SSCs); they showed that swells (long wavelengths with periods of > 7s) and wind-waves (shorter wavelengths with periods of < 7s) had an effect on suspended sediment concentrations at different depths. Longer wavelengths would suspend sediments in both shallow and deep waters, while those with shorter wavelengths would suspend sediments only at shallow depths. Sediment movements within the marine environment are especially detrimental to recruiting organisms such as corals and other invertebrates, which can compromise the resilience of reefs. Studies on sedimentation in the Cook Islands are very limited and we can only draw from the literature and observations to understand its impact. For example, Kirk (1980) conducted a study of sedimentation for Ngatangiia Harbour and Muri Lagoon on Rarotonga, which included information on current flow and change in delta position (Figure 9 & 10). Indeed, the last 20 years in the Cook Islands have seen an increase in swell frequency due to increased cyclones (de Scally, 2008), and has driven changes of coastal areas and sand movements within lagoons to increase accordingly. The impact of these changes are likely exacerbated by poorly planned coastal development and lagoon dredging projects, especially on Rarotonga and Aitutaki. In addition, run-off sediment from development on sloping lands, especially on Rarotonga and to a lesser extent Aitutaki, have also increased, brining large plumes of sediment to the marine environment during heavy rain events. In the northern group and some islands in the southern group (i.e., Palmerston, Manuae, Aitutaki), sand movement within the lagoon as a result of increased frequency of high seas in the last 20 years may also explain the noted decline in pa`ua populations and slow recovery of reefs throughout the Cook Islands (Rongo and Dyer, 2014).

Figure 9. Current directions in Muri lagoon. Water comes in over the reef and most moves in a northerly direction and out Ngatangiia passage (reproduced from Kirk, 1980).

Figure 10. Change in the position of the Avana delta between 1955 and 1979.

2.2.5 Sea level Paleoshoreline records of sea levels in the Pacific region (e.g., Linsley et al., 2000; Moriwaki et al., 2006; Goodwin & Harvey, 2008) can provide insight into forecasting and understanding trends (Dickinson, 2001). In 1993, a SEAFRAME (Sea Level Fine Resolution Acoustic Measuring Equipment) gauge was installed at Avatiu Harbour, Rarotonga, Cook Islands, by AusAID for the South Pacific Sea Level and Climate Monitoring Project (“Pacific Project”), to assist FORUM member countries in monitoring potential impacts of climate change on sea levels in the region (AusAid, 2009; Figure 11). The gauge is part of an array deployed across the Pacific, collecting high resolution data on sea level, air and water temperature, atmospheric pressure, and wind speed and direction since installation. Sea level rise predicted from 3 – 4 mm per year will severely impact the livelihood of low lying atoll communities. Already coastal communities are experiencing regular king tides and storm surge events that cause coastal erosion (e.g., Pukapuka in the northern group; Figure 12), crop damage, affect drinking water wells, and devastate coral reefs and wetland ecosystems as well as domestic dwellings and public infrastructure. For Rarotonga, sea level has been rising at 4.3 mm per year for the past 20 years (Blacka et al., 2013), which is a slightly higher rate than the global average of 3.2 ± 0.4 mm per year, and it is predicted to keep rising at an average rate of 4.7 mm per year. At this rate, future coastal damages from tropical cyclones will be unprecedented.

Figure 11. The regional distribution of the rate of sea-level rise measured by satellite altimeters from January 1993 to December 2010, with the location of Cook Islands indicated. Taken from Ngari et al., 2011.

The Special Report on Global Warming of 1.5°C held in Incheon, Republic of Korea was approved by the IPCC, which highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. The report suggested that by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. 25

Figure 12. Eroded coastline on the island of Penrhyn. Photo taken in 2016 by Teina Rongo.

2.2.6 Sea temperature The temperature of the ocean is an important factor that can influence – among other factors – the availability of food, composition of species, the migration of species, the severity of natural disasters, the salinity of the ocean, and overall the health of an ecosystem especially in the marine environment. For example, Hiddink and ter Hofstede (2008) showed that in the North Sea, temperature has increased from 1975 to 2006 by 2 °C. Subsequently, they noted that species diversity has increased from 60 to 90 species, as lower latitude species have expanded their range to higher latitudes. Most of these species were the more resilient types (faster growth rate, smaller sized, early maturation) with very little commercial values. Also, Meekan et al. (2003) showed a positive correlation between temperature and larval growth. Similarly, Green and Fischer (2004) showed that increased temperatures can lead to increased larval development and the swimming ability in fishes. Because connectivity among populations depends on the pelagic larval duration of marine organisms (Shanks et al., 2003), these result suggests that warmer ocean can lead to higher natal retention and population fragmentation, which can increase the risk of extinction. Perhaps the most important for the tropics is that warmer temperatures will increase coral bleaching; it is predicted that coral bleaching will become an annual event rather than the 4 – 7 year cycles note in the last few decades (Hoegh Guldberg, 1999; Hoegh Guldberg et al. 2007; Veron et al. 2009). Warming trends are evident in the Cook Islands with data from Rarotonga showing an increase in the annual number of ‘warm’ nights and a decrease in the number of ‘cold’ nights from 1934 – 2011 (Figure 13; PACCSAP 2014). No such trends were recorded at Penrhyn in the northern group from 1941 – 1991. There is high confidence that temperatures will continue to rise in the Country (see PACCSAP 2014).

Figure 13. Observed time series of annual average values of mean air temperature (red dots and line) and total rainfall (bars) at Rarotonga. Light blue, dark blue and grey bars denote El Niño, La Niña and neutral years respectively. Solid black trend lines indicate a least squares fit. Figure taken from PACCSAP 2014.

Although we lack long term ocean temperature data for the Cook Islands, it is assumed that ocean temperatures are also getting warmer based on the increased frequency of coral bleaching events (e.g., Hughes et al., 2017). Under a high global carbon emission scenario, sea surface temperatures are predicted to increase between 0.5 and 0.9 ºC in the Southern Group and 0.4 and 1.0 ºC in the Northern Group by 2030. Such changes could move temperatures beyond the range tolerated by some native species. Therefore, there is an urgent need for countries of the world to immediately reduce greenhouse gas emission in order to curb future warming to secure the future for coral reefs.

2.2.7 Light The availability of light is central to the health and productivity of seagrasses and other plants as well as the symbiotic relationship between some animals (for example corals and clams) and algae. Levels of available light control the depth range of marine plants as well as animals which rely on photosynthesis through symbiosis with plants (Week et al., 2012). Light levels in the marine environment is determined by both depth and turbidity that also depends on habitat. In the Cook Islands today, the lagoon environment tends to have low light levels when compared to most fore reef habitats. Turbidity is affected by a number of external factors, such as sediment becoming re-suspended by wind, currents and tidal changes, sediments from land-based run-off, and resuspension of dredged materials. The latter is a big concern for Aitutaki; multiple dredging over the years within the lagoon has created a turbid environment for most of the nearshore areas of Aitutaki (Figure 14).

Mean; Whisker: Mean±0.95 Conf. Interval

20 Pacific Resort Arutanga Wharf Maina Sunset Waste Management 16 Tautu Wharf Tepaki 12

TSS(mg/L)

0 2008 2009 2010 2011 2012 Year Figure 14. Left: Turbid waters have become the norm for nearshore lagoon sites on many islands in the Cook Islands (photo taken in 2008 by Teina Rongo in Aitutaki). Right: Total Suspended Solids (TSS [mg/L]) recorded for selected sites along the coast of the Aitutaki (modified from main island monitored by the Ministry of Marine Resources; dotted red line indicates the threshold level of TSS (4 mg/L) considered detrimental for coral reefs.

2.3 Current condition and trends of chemical processes 2.3.1 Nutrient cycling Nutrient cycling is enabled by a great diversity of organisms and leads to the creation of a number of physical structures and mechanisms that regulate the fluxes of nutrients among compartments. Nutrient cycling describes the movement within and between the various biotic or abiotic entities in which nutrients occur in the global environment. These elements can be extracted from their mineral or atmospheric sources or recycled from their organic forms by converting them to the ionic form, enabling uptake to occur and ultimately returning them to the atmosphere or soil. The flux of particles sinking from the surface ocean is key for driving ocean biogeochemical cycling. While atmospheric dust play an important role in supplying Particulate Organic Carbon (POC) to the deep seafloor, a model suggested that lithogenic associated POC flux from riverine or directly erosional in origin was also important (Dunne, et al., 2007). Nutrients such as nitrate and phosphate which are naturally present in seawater are essential for the growth of phytoplankton and other marine plants which form the base of the food web. Elevated nutrients concentrations can lead to increased marine plant biomass for both macro-algae and phytoplankton; the latter can also lead to outbreaks of the coral predator Acanthaster planci (Birkland, 1982) that can decimate an entire reef (Devaney and Randall, 1973; Sapp, 1999). The guidelines for nutrient concentrations for the protection of coral reef health are 14μg/L for dissolved inorganic nitrogen (DIN), which is made up of nitrate and ammonia (NO3-N + NH4-N), and 2.6μg/L for dissolved reactive phosphorus (DRP) (Bell 1992). The ANZECC (2000) guideline values for streams that are a cause for concern in tropical areas, based on measured values, are 10μg/L for nitrate (NO3-N) and ammonia (NH4-N), and 4μg/L for DRP (ANZECC 2000).

2.3.2 Ocean pH

The ocean absorbs around 30% of carbon dioxide (CO2) released into the atmosphere. Consequently, with more CO2 going into the atmosphere, more is taken up by the ocean. With more CO2, the ocean will become more acidic, decreasing the availability of carbonate ions needed by calcifying organisms like corals, clams, and crustaceans (e.g., crabs and lobsters) to make their skeleton (Kleypas et al., 1999; Hoegh-Guldberg et al., 2007; Veron, 2011). Although there is limited information available on the impact of ocean acidification on coastal ecosystems to date, studies have shown that increased CO2 in the ocean ̶ especially at levels projected for the middle and the end of this century ̶ can reduce fertilization and settlement success of reef-building corals (Albright et al., 2010), which is problematic for small island nations considering the goods and services these ecosystems provide. Furthermore, the impact of acidification on reef health is likely to be compounded by other stressors including coral bleaching, storm damage, and fishing pressure. Ocean acidification is expressed in terms of aragonite saturation state – aragonite is a form of calcium carbonate used by hard reef-building corals to build skeletons so it can be treated as a proxy measure for coral reef growth rate. In the Cook Islands, the aragonite saturation state has declined from about 4.5 in the late 18th century to an observed value of about 4.1 ± 0.2 in 2000, and there is very high confidence that it will continue to decrease as atmospheric CO2 concentrations increase (PACCSAP 2014). Under business-as-usual scenarios, scientists say oceans could be 150% more acidic by 2100. There is very high confidence in this projection as the rate of ocean acidification is driven primarily by the increasing oceanic uptake of carbon dioxide, in response to rising atmospheric carbon dioxide concentrations. Ngari et al. 2011 suggest that “[p]rojections from all analyzed CMIP3 models indicate that the annual maximum aragonite saturation state will reach values below 3.5 by about 2050 in the Southern Cook Islands and 2065 in the Northern Cook Islands” (Figure 15).

Figure 15. Multi-model projection, and their associated uncertainty (shaded area represents two standard deviations) of the maximum annual aragonite saturation state in the sea surface waters of the Northern Cook Islands (top) and the Southern Cook Islands (bottom) under the different emission scenarios. The dash black line indicates the aragonite saturation state at 3.5. Taken from Ngari et al, 2011.

2.3.3 Ocean salinity Salinity varies little in most marine environments and saltwater is normally between 34 ppt and 36 ppt in areas away from freshwater influences (Smith 2004), and plays an important role in the distribution of aquatic species. Some species have very specific optimal ranges for salinity while others easily transition. For example, the mud crabs (Scylla serrata) found on Aitutaki and Rarotonga can live in a wide range of salinity from brackish to ocean salt water. Many species of fish and invertebrates will move from the ocean into the estuaries or vice versa during different parts of their life cycles. A number of species in the Cook Islands (e.g., Macrobrachium lar) spend the early part of their life cycle in the brackish conditions of stream-mouths and the adult phase in a fresh water environment upstream. Salinity is one of the parameter measured in water quality monitoring programs on Rarotonga, Aitutaki, and to a lesser extent Manihiki (e.g., Anderson et al, 2004). There are two reasons to measure salinity: 1) to gather information

30 on the rates of evaporation and precipitation, and therefore the hydrological cycle, and 2) to gather information on the density of water (i.e., fresh water is less dense, and salty water is heavier). Salinity and temperature together, can help determine the varying density fields within a lagoon or ocean area that can help determine which way the currents are flowing.

2.4 Current condition and trends of ecological processes 2.4.1 Microbial processes Chlorophyll a and total suspended solids measure phytoplankton biomass, inorganic and organic particulate material in the water respectively. Elevated concentrations of both have been shown to impact negatively on coral reef health above concentration of 0.5mg/L and 4-5mg/L respectively (Bell, 1992). Increased inorganic and organic materials entering lagoons are often associated with increases in bacteria numbers and are disease-causing organisms. Enterococci bacteria are used to indicate the potential presence of human pathogens in marine and freshwater environment. Guidelines have been developed by the World Health Organisation (WHO) for contact recreation using Enterococci numbers (Table 4). This guideline is also used for freshwater samples to evaluate the bacterial water quality of the streams as they flow directly into the lagoon and are likely to impact the bacterial water quality of the lagoon.

Table 4. WHO Standards for Bathing Water Quality (taken from the Cook Islands Ministry of Marine Resources water quality reports).

There is little known about the deep sea environment due to the challenges of accessing this zone. For example, there is still much to learn on the formation and maintenance of deep-sea ferromanganese/polymetallic nodules 140 years after their discovery, though global interest has increased to mine these resources for their concentration of rare metals (Tully and Heidelberg, 2013) for use in modern technological devices today. Microbial metabolisms may play a role in the community structure of microbes associated with nodules and their surrounding sediment (see Tully and Heidelberg, 2013). In light of the Cook Islands’ interest in mining Manganese nodules in our region (see Section 5.10 for deep sea mining overview), understanding the different biological, ecological, and chemical processes operating at these depths is critical.

2.4.2 Particle feeding Many sessile marine animals have adapted to extracting organic matters from the surrounding water as food and are referred to as particle feeders, which also include filter feeders and detritivores. Particle feeders can range from the large migratory baleen whales to the microscopic zooplanktons aggregating in nutrient rich waters of upwelling regions. Most marine invertebrates, such as sea cucumbers, vermetid snails, crustaceans, sponges, giant clams, and corals are particle feeders. Some play a critical role in the food web (i.e., zooplankton and phytoplankton) and play an important part in the cycling of energy and nutrients. Many of the reefs today host a variety of particle feeders due to its degraded state from nutrient loading. In the Cook Islands, the Ministry of Marine Resources has conducted stock assessments of sea cucumbers on islands in-country (e.g., Aitutaki, Mangaia, Palmerston, and Rarotonga; Raumea et al., 2013). However, poor land-use- practices and development on sloping lands, coastal areas, and marine dredging activities within the lagoon have increased sediment load on coral reef habitats and have destroyed populations of particle feeders. For example, the kuku (Mylitus spp.), a tropical mussel that used to cover entire reef flats on Rarotonga, are now rare (T. Rongo, pers.com.). In Aitutaki, increased dredging activities within the lagoon in the last 20 years have increased sediment load within; according to residents of Aitutaki, their lagoon has become more turbid (Rongo and Dyer, 2014). Sedimentation and turbidity can not only affect coral survival and growth, but can also change coral composition with the prevalence of a few species that can tolerate such conditions (Rogers, 1990); it is likely that such a situation is occurring on many coral reefs in the Cook Islands, especially those with lagoon habitats.

2.4.3 Primary production When nutrients are available in the marine environment, it can drive the proliferation of microscopic plants also known as phytoplankton – as observed via satellite using chlorophyll-a concentration. In the ocean, high primary production tends to occur at upwelling regions where nutrients from the bottom of the ocean are transported via upward currents. To the north of the Cook Islands, there is an upwelling region that is associated with the equatorial counter currents (Figure 16), and thus primary productivity there is higher when compared to the southern group. It has been shown that subtropical regions of the Pacific are low in primary productivity (Figure 17). Therefore, the Cook Islands is a nutrient poor region with chlorophyll-a concentration < 0.1 mg/m3 in the open ocean. However for nearshore environments, primary productivity is high especially around the most developed islands (i.e., Rarotonga and Aitutaki), where nutrient levels are above the recommended standards (e.g., Bell, 1992).

Figure 16. Chlorophyll-a concentration (mg/m3) in the Pacific ocean (taken from https://www.youtube.com/watch?v=sGB- sqrLZ9U). Area delineated in white is the Cook Islands EEZ.

Figure 17. Zonal integrals of primary production in units of Pg C a-1 deg-1 . Lines represent the three primary productivity algorithms of Behrenfeld and Falkowski [1997] (solid line), Carr [2002] (dashed line), and Marra et al. [2003] (dotted line). This plot was modified from Dunne et al. (2007).

2.4.4 Herbivory Although nutrient limitation on reefs may influence phase shifts on reefs (i.e., coral- to algal-dominated), the general consensus among top-down advocates is that grazing by herbivorous species are important in keeping algal biomass low to promote recovery (Ogden & Lobel 1978; Sammaco, 1980; Carpenter, 1981; Hughes, 1994); alternatively, bottom-up advocates refer to the concentration of nutrients in the environment (i.e., nitrate, phosphate, silica, iron, etc.), that can control plant growth. For example, Carpenter & Edmund 2006 showed that the recovery of urchins after disease was related to the recovery of corals in the Caribbean. In addition, a large-scale caging experiment conducted on the Great Barrier Reef by Bellwood et al. (2006) showed that certain functional groups (i.e., batfish) can reverse phase shifts. Subsequently, there is much debate in the literature as to which herbivorous functional groups are more important (i.e., vertebrates vs invertebrates). Some argue that overfishing of herbivorous fishes were the reason for the algal phase shift in the Caribbean (Jackson et al. 2001; Pandolfi et al. 2003; Bellwood et al. 2004). In addition, Mumby et al. (2006) showed that grazing by large herbivorous fishes were more effective at removing algae; Aronson & Precht (2001, 2004), on the other hand, argue that urchin grazing was more important, and referred to overfishing in the Caribbean mainly targeting carnivores (e.g., snappers, sharks) not herbivorous fishes, yet reefs remain algal-dominated (Aronson & Precht, 2006). The argument that urchins may be more important was supported by Szmant (2002) who suggested that large macroalgae (e.g., Lobophora, Dictyota) that are chemically defended (Hay, 1984) has escaped herbivory and can only be removed by urchins. In the Cook Islands, and like most reefs in the Pacific, functional redundancy is high; such that if the abundance of one species is compromised through overfishing or disease, other species will fill their role on reefs and prevent phase shifts. For example, a mass die-off of the urchin Echinothrix diadema on Rarotonga (Cook Islands News 2016 a,b), Mauke, and Mitiaro, which is an important grazer did not result in a phase shift. Indeed, the abundance of herbivorous fish species have been noted to be healthy, especially on Rarotonga (Rongo and van Woesik, 2013). When compared with other reefs in the Pacific, a recent study showed that herbivorous fish biomass was higher even against uninhabited islands like Millennium Island in the Line Islands (Sandin et al., 2018; Figure 18), arguably the most pristine reef in the world. However, a healthy herbivorous fish population can also indicate a degraded reef dominated by algae. The prevalence of ciguatera fish poisoning on Rarotonga over almost 30 years has indeed reduced fishing pressure drastically, which contributed to the increase of herbivorous fish biomass over the years.

Figure 18. Total reef fish biomass by trophic guilds of a select number of Pacific islands compared to Rarotonga (taken from Sandin et al., 2018).

2.4.5 Predation

Over the past 60 years, global ocean has lost more than 90% of large predatory fishes (Myer and Worm, 2003), a trend that is also evident for inshore fisheries (e.g., Jackson et al., 2001). To date, there are limited reliable data in the Cook Islands to show a decline of fisheries for both inshore and pelagic species, although local knowledge ascertain otherwise (Rongo and Dyer, 2014). Species like sharks have limited information to determine their trend, but local knowledge suggest some mix results. While for some islands fishers argue that shark populations has increased, others suggest a decline. Rarotonga is one island where local knowledge suggests a decline in shark populations over the years for reasons unknown. The extraction of predators such as tuna and billfish species in the Cook Islands via foreign fishing vessels has been recorded by the Western and Central Pacific Fisheries Commission via Annual Country Report (Table 5; Ministry of Marine Resources, 2018).

Table 5. Annual catch estimates in metric tonnes for all licensed foreign vessels by gear within the Cook Islands EEZ, for tuna and billfish species in 2017. Operational log sheet data was raised using VMS data, with 79% log sheet coverage for foreign flagged longline vessels and 86% log sheet coverage for foreign purse seine vessels. Taken from the Ministry of Marine Resources (2018).

2.4.6 Recruitment Recruitment refers to the first settlement of individuals from the pelagic environment to juvenile habitats. During the latter part of the 19th century and early 20th century, migration of pelagic fisheries was believed to be the reason for fluctuations in catches over time. Such that during years of low yield, only a few are returning to the fishing ground. However, Hjort (1914) proposed the recruitment limiting hypothesis as a reason for the fluctuation. Subsequently, early life histories studies of marine organism increased to understand population distribution and dynamics. This important process on reefs are poorly understood in the Cook Islands. To date, there are no published field studies that examined recruitment processes in the Cook Islands for any species. Yet, local knowledge has confirmed that the recruitment of important food fishes and invertebrates (i.e., giant clam Tridacna maxima; Figure 19) have declined significantly throughout the Cook Islands (Rongo and Dyer, 2014). For example, large schools of surgeonfish (e.g., Ctenocheatus striatus and Siganus argeantus) used to be common sights during the months of February to April in Rarotonga.

Figure 19. Pa’ua (Tridacna maxima) is an important food source in the Cook Islands. Today, Manuae is the only island in the Cook Islands where a healthy population still exists (photo taken on Manuae by Teina Rongo in 2005).

2.4.7 Connectivity Connectivity in the marine system is critical for the replenishment/recovery and the resilience of an ecosystem. The issue of whether marine ecosystems are “open” (replenishment of populations rely on outside sources) or “closed” (populations are self-seeding) has been a topic of much debate in the literature for decades. While there is less support for “open” systems (e.g., Swearer et al., 1999; Jones et al., 1999), marine systems are not entirely closed (e.g., Baums et al., 2005). In support, Treml et al. (2008) suggested that recruitment to reefs in the Cook Islands may be fed by a strong westward current from French Polynesia during El Niño years (Figure 20). Connectivity also depends on the pelagic larval duration of marine species and the distance between source and the receiving habitat. In 2014, Rongo et al. (2014) suggested that connectivity among islands may be key to the survival of marine ecosystems for islands between Aitutaki in the northwest to Ma’uke in the southeast.

Figure 20. Difference in connectivity between years for a 30-day PLD (pelagic larval duration) during the coral mass spawning season of October through December. Taken from Treml et al. (2008).

2.5 Current condition and trends in terrestrial habitats that support the islands of Marae Moana 2.5.1 Saltmarshes Saltmarshes are coastal ecosystems in the upper coastal intertidal zone between land and open saltwater, or brackish water that is regularly flooded by tides. Saltmarshes are nursery grounds for a diversity of marine species, but also a feeding ground a diversity sea birds and people. The majority of these habitats exist in the northern group, where they are important nursery ground for milk fish or locally known as ava (Chanos chanos), which is an important food fish for people on these islands. On Rarotonga and Aitutaki, many of the saltmarshes have been dredged and filled for development while the remaining also await a similar fate.

2.5.2 Wetlands Wetland habitats are places where land is covered by freshwater. Globally, 300 to 400 million people live near a wetland and depend on them for the cultivation of a variety of food crops and a diversity of fish, invertebrates, birds, and other animals (https://www.worldlife.org). On high islands in the Cook Islands, these habitats are remnants of past marine lagoons that have been cut-off from ocean circulations over years of coastal buildup from a combination of reef growth and cyclone events. These habitats are often undervalued, yet they are considered “the planets natural waste water treatment facility”. This treatment process is critical for coral reefs that require an oligotrophic environment to survive. While wetland habitats in the Cook Islands are often planted with taro (Figure 21), westernization and lifestyle change have now led to the abandonment of these habitats for agricultural purposes and are now being filled for development. For example, many wetland habitats on the south-eastern exposure of Rarotonga have been filled for tourism development. Consequently, this likely increased nutrient loading in the marine environment causing frequent episodes of algal blooms along this coast. Indeed, wetland protection needs to be stringent, to protect the interest of the Marae Moana.

Figure 21. Taro plantation in Ruatonga on the island of Rarotonga. Photo by Jackalyn Rongo.

2.5.3 Riparian zone Riparian zones are the interface between the land and the stream or simply the stream bank. These zones are critical for the maintenance of a healthy downstream habitat, especially during flood events where large amounts of terreginous sediment can be transported to the marine environment. In particular, riparian vegetation can secure stream banks and minimize erosion. However, there is no concerted effort to manage riparian zones properly. In most places, they are overgrown by invasive vegetation, and to a lesser extent are gabion rock walls constructed to protect and prevent further erosion of roads and private properties. Indeed many of the stream banks have been eroded and are contributing to sedimentation in the marine environment.

2.6 Current condition and trends of outbreaks of disease, pests and introduced species

2.6.1 Outbreaks of disease Diseases of scleractinian corals and associated species have increased in number in recent years, and they are now recognized as important phenomena capable of altering the structure and composition of coral reefs. Since the early 1990s, there has been a concerted effort to characterize coral diseases, including the application of novel molecular tools to confirm identities of pathogens and understand mechanisms of host response including resistance. Diseases affecting corals around the world have increased in frequency and severity. Coral reef disease is especially a problem in the Caribbean, with the last three decades seeing major community shifts from coral-dominated to algal- dominated reefs. Yet we are only beginning to understand enough about drivers of disease outbreaks to consider management actions. While diseases affecting corals have increased since the 1970’s, information on disease are still scarce especially in the Pacific. A survey conducted in Manuae in 2013, recorded the presence of yellow-band disease that appeared to be in an outbreak situation which devastated a large reef slope area (Rongo et al, 2013; Figure 22).

Figure 22. Extensive reef slope area on Manuae was devastated by a coral disease believed to be yellow- band disease. Disease lesions were apparent on large, platy Astreopora colonies (a & c), and other species such as Millepora platyphyla (b) and Acropora spp. (d); turf algae were seen overgrowing the recently killed colony. Red arrow indicates area of the disease. Photos taken from Rongo et al. (2013). 39

2.6.2 Outbreaks of Crown-Of-Thorns Starfish Crown-Of-Thorns Starfish (COTS) outbreaks are likely the most important disturbance on reefs in the Cook Islands. During COTS outbreaks, most large coral colonies are killed off, and often the small and encrusting colonies survive (Figure 23). In the 1970s, Devaney & Randall (1973) documented the first reported COTS outbreak on Rarotonga during a Pacific-wide outbreak (Sapp, 1999). According to their report, most of the damage occurred between Ngatangiia/Matavera (northeastern side) counter-clockwise to Arorangi (western side). A second COTS outbreak in the mid- to late-1990s, limited to fore reef communities, reduced coral cover from more than 40% to less than 5% in 2006 (Rongo et al., 2006). The recovery after the 1970s outbreak occurred over a period of less than 10 years according to interviews with locals. However, reef recovery from the second COTS outbreak has been slow, even after 12 years. Similar COTS outbreaks were reported in Aitutaki in the early 1970s and again in the mid-1990s and 2010 (Rongo et al, 2010, Bruckner et al, 2014). Similar outbreaks may have also occurred on other islands in the southern group, but reports on these are not available. In the northern group, Devaney & Randall (1973) reported an outbreak in the late 1960s to the early 1970s in Penrhyn. With regards to controlling COTS outbreak, a proactive containment of outbreaks at source reefs is critical (e.g., Walshe and Anthony, 2017).

Figure 23. Crown-of-thorns starfish outbreak in Japan (Photo by Robert van Woesik)

2.6.3 Introduced species An introduced species is a species living outside its native distributional range, but which has arrived to the new location by human activity, either deliberate or accidental. Deliberate introductions have been for food and commercial purposes, while others are as biological control agents to combat pests. In the Cook Islands, the impact of introduced species is more prevalent in the terrestrial environment especially with plants (e.g., Cook Islands News 2018); there has also been several introductions into the marine environment. The most documented is the introduction of trochus (Trochus niloticus; Figure 24) by the late Ronald Powell to Aitutaki in 1957 from Fiji, where 600 shells were transferred and only 320 survived (Nash et al., 1992); the species was further introduced to other islands in country during the 1980’s. In 1983, 200 trochus were transferred to Rarotonga from Aitutaki and placed on the reef flat at Avatiu. A second transfer took place in 1986, when 2,000 adult trochus were placed on the shallow reef slope off Muri.

Figure 24. Trochus niloticus. Photo by Gustav Paulay taken on a Guam reef.

2.6.4 Other outbreaks Ciguatera poisoning was also a major problem in Rarotonga in the 1990s onwards (Lewis, 1986; Rongo and van Woesik, 2011; 2013), which may have contributed to Cook Islanders shifting away from consuming reef fishes to more imported goods, which had negative health implications (Rongo and van Woesik, 2012). Temporal studies of fisheries in the Cook Islands, namely Aitutaki and Mangaia, were collated which examined a shift in fish hook technology over time (Allen, 1992). Cook Islander Dr. Teina Rongo utilized this information along with examining paleoclimate data (Linsley et al., 2006) to formulate a novel theory that ciguatera may have prompted the late Holocene Polynesian voyages of discovery (Rongo et al., 2009); this theory received international coverage (e.g., EurekAlert! 2009; Honolulu Advertiser, 2009; Phys.org, 2009; ScienceDaily, 2009) and was also incorporated into Disney’s movie Moana that was released in 2016 (Smithsonian Magazine, 2016).

2.7 Assessment summary – Ecosystem health This assessment examines five main areas – physical processes, chemical processes, ecological processes, terrestrial habitats, and outbreaks of disease.

2.7.1 Physical processes Because we have limited data, it is difficult to suggest with confidence how physical processes have changed in the last few decade, especially with most variables in the marine environment. While changes to these physical processes will be influenced by the natural fluctuations associated with climate oscillations (i.e., ENSO and IPO/PDO), there is a general consensus that changes particularly with rainfall, sedimentation, sea temperature, light, and cyclone intensity are expected to create a challenging environment for the desirable marine life within Marae Moana. In addition, the contribution of climate change will worsen the situation.

2.7.2 Chemical processes Although we lack reliable data (except for Rarotonga and Aitutaki) to determine the status of the chemical environment for the Cook Islands, based on local knowledge, the coastal environment has seen to be deteriorating especially in the lagoon and reef flat habitats are evident with regards to the loss of hard corals and other food resources (e.g., pa`ua or Tridacna maxima), and the increased cover of macro-algae. For example, Ngatangiia lagoon is the most studied lagoon in the Cook Islands with studies suggesting that water quality is below the recommended standard (McCue et al., 2018). Conditions are expected to continue to worsen as development increases with poor land-use practices to cater for tourism. Moreover, as the concentrations of atmospheric carbon dioxide increases, we also expect ocean acidification to emerge as a serious threat for the coral reefs of the Cook Islands.

2.7.3 Ecological processes Most ecological processes remain intact for most islands of the Cook Islands, but noted changes with coral loss associated with bleaching due to elevated sea surface temperatures may be expected to worsen in the future. There is little to no information on other processes such as predation, herbivory, and primary production.

2.7.4 Terrestrial habitats that support the islands of Marae Moana Terrestrial habitats supporting the marine environment such as wetlands, salt water marshes, riparian zones, and slope lands have very little information.

2.7.5 Outbreaks of disease and introduced species Outbreaks of disease such as those noted in Manihiki and Penrhyn in the 1990s, which devastated the pearl industry, are well documented (e.g., Ponia, 2000); other diseases affecting other invertebrates (i.e., corals and urchins) have been recorded but not properly studied and monitored over time. Thus, it is difficult to determine the cause and trend of these diseases in the Cook Islands at present.

2.7.6 Overall summary of ecosystem health Indeed, there is a need to develop a robust monitoring program to measure these parameters, especially with predictions of climate change impacts worsening in the future. Most importantly, to build local capacity to be able to carry out this work efficiently.

3. BIODIVERSITY

3.1 Background A variety of marine-related research has been conducted in the Cook Islands that provide some record of biodiversity within the country. Species identified through research and by visiting taxonomists to the Cook Islands has been recorded in a database established in 2003 under the Cook Islands Natural Heritage Project (http://cookislands.bishopmuseum.org/search.asp) . In 2011, the Cook Islands National Environment Service compiled the Cook Islands’ first report on biological diversity (Passfield and Rongo, 2011), with the second report compiled in 2017 (Butler, 2017). It is clear that of the terrestrial biodiversity is better understood in the Cook Islands when compared with its marine counterpart; it is likely that new marine species or new records for the region will be discovered in the future not only in the deep water environment but also in the shallow coral reef environment. For example, the coral family Acroporidae is yet to be properly identified for the Cook Islands; there have been recent efforts around June 2019 through collaboration with researchers from James Cook University (e.g., Dr. Thomas Bridge, Senior Curator - Corals) to help elucidate identification of this family in the Cook Islands.

3.2 Legacies and shifted baselines The term “shifting baseline” was first coined by Daniel Pauly in 1995. Since then “the idea of humans perceiving nature inaccurately, through ‘shifting baselines’, has taken the conservation world by storm: the theory appeared to describe a commonly noticed problem regarding people’s view of the natural world around them. The shifting baseline syndrome is the situation in which over time knowledge is lost about the state of the natural world, because people don’t perceive changes that are actually taking place” (Mongabay, 2009). Our understanding of the marine environment is from research that has been conducted in ecosystems that are to some extent degraded, and there is limited information of how these ecosystems operated in the absence of human activity (Knowlton & Jackson, 2008). Marine monitoring in the Cook Islands started in the early 1990s, particularly for Rarotonga and Aitutaki. Before this period, our understand of reefs come from sporadic studies by foreign researchers. Apart from research, our knowledge of shifting baselines come from elders in the community who remember how conditions were for the different islands in the Cook Islands (Rongo and Dyer, 2014).

3.3 Current condition and trends of habitats to support species Reef ecosystems in the Cook Islands consist of a variety of habitats from the intertidal and lagoon/reef slopes to open ocean. Although more biodiversity work is needed for the Cook Islands, most of what we know stem largely from nearshore habitats (e.g., lagoon/reef flat and forereef slopes). Indeed, the overall condition of the region’s biodiversity depends on not only managing the use of these habitats effectively and maintaining the interconnections between them, but also managing land-based activities that can also have significant impact on marine habitats.

3.3.1 Land beaches and coastlines The beaches and coastlines are an important link to the marine environment and their condition can influence the state of adjacent habitats. Sandy beaches support a wide range of species including nesting grounds for seabirds and marine turtles. Saltwater marshes that are typically enclosed embayment for the low lying atolls or adjacent to river mouths and estuaries on high islands like Rarotonga are critical nursery and feeding ground for many species. They also act as depositional areas for sediments and nutrients discharged from the catchment or transported along the coast. Unfortunately, beaches and coastline are being threatened by development in the Cook Islands. For example, the health of these habitats are being degraded by coastal dredging activities and the construction of artificial barriers (e.g., sea walls) and in some places the removal of trees.

3.3.2 Coral reefs Coral reefs make up only 0.2 % of marine areas, yet they host approximately one-third of all described marine biodiversity (Reaka-Kudla, 1997, 2003). However, it is widely accepted that coral reefs around the world are in serious decline with 30% already degraded while another 60% loss is predicted in the next few decades (Wilkinson, 2002; Wilkinson, 2004; also see Hughes et al., 2003). The causes of reef degradation range from nutrient enrichment, increased sedimentation from terrestrial runoff, overfishing, global climate change (Lapointe, 1997; Richmond et al., 2008; Jackson et al., 2001; Hoegh-Guldberg, 1999; Hoegh-Guldberg et al., 2007; Veron et al., 2008, 2009), and Crown- of-thorns Starfish infestation (Birkeland, 1982).

3.3.3 Islands The Cook Islands have a total land area 241km², however this land is scattered over 2 million km2 of sea. There are 15 islands with a diversity of island formations, which are divided into a northern and a southern group spanning 1000 km across open sea (see Table 1). The islands that form the northern group are older, low lying, and predominantly coral atolls with large lagoons (Manihiki, Rakahanga, Penhryn, Pukapuka). The islands that form the southern group are the continuation of the Austral Islands, lying along the same north-east south-west fracture of the earth's crust and constitute about 90% of the total land area of the Cook Islands (Geology of Cook Islands, 2019). The largest island,

Rarotonga is volcanic with the highest point of 650 m above sea level. The second highest is Aitutaki, which has a small mountain surrounded by a atoll reef, a formation that is referred to as "almost atoll". Four islands in the southern group (Atiu, Mauke, Mitiaro and Mangaia) are called "raised makatea" that has a remarkable topography showing signs of karstification and cave development. Two of the islands (Takutea and Nassau) are referred to as “sand cays”. The diversity of islands in the Cook Islands are also a key factor that determines biodiversity within Marae Moana.

Northern Cook Islands 3.3.3.1 Manihiki Manihiki (Figure 25) is an atoll located in the northern Cook Islands at 10º 25’ S and 161 º 00’ W. It consists of two main motu, Tauhunu and Te Pae Rao Ngake e Tukao, and more than 50 smaller motus of varying sizes. There is only one small boat passage into the lagoon near the Tukao at the northern end of the atoll, and most of the reef flats between the motu are less than 1 m deep. The lagoon is studded with small islands (kāoa) on top of steep pinnacle reefs, and is characterized by a raised outer rim, which permits only minor exchanges between the lagoon and the surrounding oceans except during significant wave events. The economy of Manihiki is dominated by the cultivation of black pearls and there are pearl farms dotted around the lagoon. At its peak in 2000, the Cook Islands black pearl industry was worth $18m annually produced by 200 farmers; now there are around 25 pearl farmers who sell most of their pearls locally (Enjoy Cook Islands, 2020).

Figure 25. Google Earth map of Manihiki (10º 25’ 19.14”S, 161º 00’ 00.95”W). indicating the general areas visited in 2016 inside the lagoon (yellow), reef flat (white), and on the fore reef (red).

3.3.3.2 Rakahanga Rakahanga (Figure 26), traditionally called Tapuahua, lies approximately 162 degrees west and 10 degrees south of the Equator. It is an atoll island, located close to the island of Manihiki, and is the second farthest island from Rarotonga – the main island of the Cook Islands. Rakahanga has a very productive fisheries sector with products that are often sold in markets on Rarotonga. Black pearls have previously been farmed on the island on two pearl farms – one owned and run by the Island Council, the other by the Church. The industry however collapsed due to high population of pearl shells in the small lagoon, which led to the onset of disease in the pearl crops.

Figure 26. Google Earth map of Rakahanga (10º 00’ 57.94”S, 161º 05’ 28.61”W) with the general areas visited in 2016 on the fore reef (red dots) and in the lagoon (yellow dots) indicated.

3.3.3.3 Penrhyn Penrhyn (Figure 27) is a coral atoll with a circumference of approximately 77 km, enclosing a lagoon with an area of 233 km2. The atoll is atop the highest submarine volcano in the Cook Islands, rising 4,876 m from the ocean floor. The atoll is low-lying, with a maximum elevation of less than 5 m. The total land area is 9.84 square kilometres. Black pearl farming was previously the only significant economic activity on the island which began in 1997 – 1998, but in 2000 a disease caused by a virus killed the pearl oysters; stocks never recovered and the final harvest was in 2003. Penrhyn is also considered the most important turtle nesting ground in the Cook Islands (Michael White, pers. comm.). While Penrhyn was severely hit by the recent bleaching events associated with the El Niño event of 2015/2016 (Rongo, 2016), Penrhyn remains unknown with regards to its marine biodiversity.

Figure 27. Google Earth map of Penrhyn (8º 59’ 32.46”S, 157º 58’ 21.02”W) with the general areas visited in 2016 on the fore reef (red dots) and in the lagoon (yellow dots) indicated.

3.3.3.4 Pukapuka Pukapuka (Figure 28) consists of three islets on this manta ray-shaped island, with a total land area of approximately 3 km2: 1) Motu Kō, the biggest island is to the southeast; 2) Motu Kotawa is to the southwest; and 3) Wale, the main island to the north. Kō and Motu Kotawa are uninhabited food reserves, with taro and puraka (wild taro) gardens and coconut plantations.

Figure 28. Google Earth map of Pukapuka (10º 53’ 01.91”S, 165º 51’ 06.22”W) with the general area of sites visited in the lagoon (yellow dots) and fore reef (red dots) indicated. White dot indicates lagoon site in front of the main settlement on Pukapuka where unique coral assemblages were noted. Arrow indicates passage to the main harbour.

Rongo (2016) examined the bleaching event on Pukapuka that was associated with the 2015/16 El Nino events, and noted two species of coral in the Pukapuka lagoon that has not been reported elsewhere in the Cook Islands (e.g., Stylophora pistillata and Pavona decussata; Figure 29). Considering that Pukapuka is the westernmost island in the Cook Islands and the above-mentioned corals are common in the western Pacific, this information may be important to understand the distribution of marine species across the region. Yet, little remains known about Pukapuka’s marine environment, and more research is needed to determine their value within Marae Moana.

Figure 29. Left: Stylophora pistillata. Right: Pavona deccusata. Both corals have not been seen anywhere else in the Cook Islands, but are common in other reefs in the western Pacific. Photos by Teina Rongo.

3.3.3.5 Nassau Nassau (Figure 30) is one of two sand cay islands in the Cook Islands, located 90 km south of Pukapuka. The island has a land area of 1.3 km² with the highest point being 9 meters above sea level. Nassau is surrounded by a narrow reef flat, and is the only island of the northern group without a lagoon. The island is the most isolated of all the islands in the Cook Islands, only accessible by boat. Inland, there are rich taro swamps and fruit groves, and offshore fishing is normally good. The population of Nassau has remained relatively stable with 72 in 2001 to 78 in 2016 (Cook Islands Population Census, 2016). Very little is known about its marine biodiversity. In terms of fishing, Nassau is known for catching pelagic species. In 2017, a small cargo ship was stranded on its reef flat; in 2019s storm activities moved the ship into the island’s harbor, blocking the passage (see Figure 30).

Figure 30. Top: Nassau island (11º 33’ 40.38”S, 165º 24’ 52.36”W). Photo taken from http://www.cookislands.org.uk/nassau.html#.XllIMGhKiHs). Bottom: A stranded shipping vessel blocking the harbor entrance of Nassau. Photo taken from http://cookislandsnews.com/national/outer- islands/item/74957-750k-salvage-job-on-remote-nassau).

3.3.3.6 Suwarrow Suwarrow (Figure 31) is a roughly quadrilateral-shaped coral atoll, 80 km in circumference and with over 20 small islets surrounding a central lagoon measuring around 19 km x 8 km. In 1978, the island was declared a National Park of the Cook Islands due to the plentiful marine and bird wild life it supports. Suwarrow has rich marine biodiversity, which is rich enough to support megafauna such as sea turtles, sharks and mantas, and cetaceans including humpback, sperm, and false killer whales. Suwarrow was declared a National Heritage Park in 1978; it is an important sea-bird breeding site not only for the Cook Islands but for the region and the world, with the largest congregation of Lesser Frigatebirds in the South Pacific (Cook Islands National Environment Service, 2020).

Figure 31. Google Earth map of Suwarrow (13º 16’ 52.36”S, 163º 07’ 39.62”W).

Southern Cook Islands 3.3.3.7 Rarotonga Rarotonga (Figure 32) is the main island of the Cook Islands, with the majority of the country’s population residing here. Stoddart and Fosberg (1972) described the reef islands of Rarotonga and provided some background into visiting researcher’s general descriptions of the reefs from 1928 to the date of their publication in 1972.

Figure 32. Map of Rarotonga (21° 14’ 02.31” S, 159° 46’ 39.12” W) depicting the fore-reef sites surveyed in 1994 (Miller et al., 1994, i.e., Avatiu, Motutapu, Titikaveka), 1999 (Ponia et al., 1999, i.e., Avarua, Motutapu, Titikaveka, Kavera, Tumunu, Nikao), 2003 (Lyon, 2003, i.e., Avatiu, Avarua, Kiikii, Motutapu, Taakoka, Titikaveka, Vaimaanga, Kavera, Tumunu, Nikao), 2006 (Rongo et al., 2006, i.e., Avatiu, Avarua, Kiikii, Motutapu, Taakoka, Titikaveka, Vaimaanga, Kavera), 2009 (Rongo et al., 2009a, i.e., Avatiu, Avarua, Kiikii, Taakoka, Vaimaanga, Kavera, Tumunu, Nikao), and 2011 (i.e., Avatiu, Avarua, Kiikii, Motutapu, Taakoka, Titikaveka, Tumunu, Nikao); not all sites were surveyed in each survey year. Yellow and blue dots mark fore reef sites surveyed in 2011 as well as in previous surveys by the Ministry of Marine Resources and the National Environment Service. Red stars indicate lagoon sites surveyed in 2006 by NES and in 2011. Picture taken from Google Earth.

For the last 18 years, reefs on Rarotonga have steadily recovered despite the various disturbance regimes during this period. In 2006 the mean percent coral cover was around 1%, around 5% in 2009, 8% in 2011, 16% in 2014, and 26% in 2016 (Figure 33); a 39% increase in coral cover per year over a 10-year period, which is significantly higher than the 2.85% reported for the Great Barrier Reef in the absence of reef disturbances associated with COTS outbreak, coral bleaching, and cyclone (De’ath et al., 2012). A similar trend was indicated in the coral size class data where a significant increase of larger colonies in 2016 were noted when compared with 2006. In support, coral associated fish species (i.e., pomacentrids; e.g., Chromis vanderbilti) showed an increase as well. It was estimated that coral cover will reach the pre-COTS conditions of the 1990s (at >30%) by 2020 — a period of 19 years since the end of the COTS outbreak around 2001 (Rongo et al, 2016). In contrast, anecdotal reports suggest that recovery following the 1970s COTS outbreak took less than 10 years.

Percent Coral Cover (%) Cover Coral Percent 10

0 1994 1999 2000 2003 2006 2009 2011 2014 2016 Year Figure 33. Mean percent coral cover for all sites lumped for each year. Data taken from 1994 (Miller, 1994), 1999 (Ponia et al., 1999), 2000 (Lyion, 2000), 2003 (Lyion, 2003), Rongo et al., 2006), 2009 (Rongo et al., 2009), 2011 (Rongo & van Woesik, 2013), 2014 (Rongo et al., 2015) and (Rongo et al., 2016). Dotted red line represents the Indo-Pacific average of 21.1% estimated in 2003 (Bruno & Selig, 2007).

Indeed, factors such as cyclones, coral bleaching, eutrophication, and climate change (i.e., elevated sea surface temperature and acidification) have all increased in the last few decades and are likely contributors to the slow recovery following the recent COTS outbreak. Considering the improved state of Rarotonga’s reefs, the likelihood of COTS returning in the near future is high. Also, the mass die-off of vana (Echinothrix diadema) on Rarotonga, where a 99% loss was noted when compared with 2014 densities; the E. diadema die-off was also reported on the island of Ma’uke and Mitiaro. E. diadema is an important grazer and its loss would likely increase algal cover in habitats where

52 this species were found (i.e., forereef slope and reef crest habitats). Although, Rongo et al. (2016), suggested that the extensive coral bleaching experienced on Rarotonga that occurred during the preparation of their report from October to April of 2016 would likely show a significant decline of coral cover by 2018, this did not occur; Palumbi (2017) discovered that Rarotonga corals (i.e., Acropora hyacinthus) host thermal stress tolerant symbiodiniums that may be key for helping corals survive in the face of the various climate change scenarios.

3.3.3.8 Mangaia Mangaia (Figure 34) is the southernmost island of the Cook Islands, located around 21° 55’ 41.04” S, 157° 55’ 10.86” W; the island is approximately 196 km southeast of Rarotonga. It has a central volcanic plateau surrounded by a high ring of raised makatea cliffs of fossil coral 60 m high. The highest point is Rangi-motia, which is 169 m above sea level. According to the most recent census, Mangaia has a population of 499 (Cook Islands Population Census, 2016). There are very few marine research that has been conducted on Mangaia, especially on the fore reef habitat. Most are those conducted on reef flat habitats by the Ministry of Marine Resources to examined invertebrate and finfish populations (e.g., Morejohn et al., 2018). Mangaia perhaps well known for its archeological research pertaining to its extinct bird populations (e.g., Steadman, 1986). Mangaia is the only island in the southern group that has not reported any incidents of ciguatera poisoning.

Figure 34. Mangaia (21° 55’ 41.04” S, 157° 55’ 10.86” W). Map indicating puna boundaries, survey sites conducted by MMR in 2018, and the ra’ui areas on the western exposure (taken from Morejohn et al., 2018).

3.3.3.9 Aitutaki Aitutaki (Figure 40) is located around 18º 53’ S and 159º 46’ W, and approximately 263 km north of Rarotonga. Geologically, the island is an almost-atoll around 18 km2 in area, with a substantial residual volcano about 124 m high aged ~8.1 million years. The mainland is about 16 km2 in area with a moderate-sized lagoon and 15 small islets (motu) around its perimeter. In 2011, the total population was 2,038, which has remained relatively stable in the last 10 years; Aitutaki is the second most populated island in the southern Cook Islands after Rarotonga (Cook Islands Census, 2011). Aitutaki was once a hub of agriculture activities in the 1950’s and 60’s second to mainland Rarotonga, exporting bananas to the New Zealand market and oranges to the Island Foods Canning factory in Rarotonga. Aitutaki also produced and supplied pia (arrowroot starch), pa`ua (clams), remu (seaweed), tupa (crabs) and fish to families and friends on other islands and those travelling abroad. Currently, tourism is well established as the main economic activity on the island, offering employment opportunities for the local population. Increasingly, a lot of fertile land is uncultivated due to a lack of reliable transportation and market opportunities, population decline, and pest infestations of agricultural crops. Increasing development in the last twenty years to meet the demand of the tourism industry, along with reef disturbances (e.g., climate change impacts, COTS outbreaks, coral disease, and cyclones), pose threats to the existence of this delicate ecosystem.

Figure 40. Map of Aitutaki (18º 53’ 07.36” S, 159º 46’ 36.05” W). with yellow dots indicating the two sites surveyed during this expedition; these two sites were established in 2008 (see Rongo, 2008). Green area near motu Maina indicates the area where the team conducted a snorkeling tour as part of the survey preparation. Taken from Google Earth.

Over the last 20 years, several coral reef surveys have been conducted in Aitutaki that have been critical in our understanding of temporal changes on these reefs. During the 1990s, the reefs of Aitutaki went through several natural disturbances; a bleaching event in the early 1990s (Goreau & Hayes, 1995) followed by a COTS outbreak in the late 1990s (Rongo, 2008), likely damage from cyclone Pat in 2010, and a recent outbreak observed in 2013 (Bruckner, 2013; Rongo et al. 2013). A detailed report was published in 2000 regarding the various fishing marine activities conducted in Aitutaki, ranging from traditional to modern fishing methods (MMR & SPC, 2000).

The Cook Islands Ministry of Marine Resources have been monitoring Aitutaki’s lagoon water quality since 2004 where 11 sampling sites established, and new sites were added in subsequent years including stream sites (e.g., Turua et al., 2006). Parameters measured include temperature, dissolved oxygen, pH, salinity, nutrients, chlorophyll a, suspended solids and bacterial contamination.

3.3.3.10 Manuae Manuae (Figure 41) is a small atoll approximately 16 km2, located about 87 km southeast of Aitutaki (19º 16’S 158º 57’W). Although Manuae is currently uninhabited with minimal anthropogenic stresses, the island in the earlier part of the 1990s was inhabited and exporting copra. The pristine coral reef ecosystem on Manuae invites the development of the island as a tourist destination. As an effort to develop Manuae for ecotourism, a dirt airstrip that could cater for small aircraft was established. However, this idea did not come to fruition. Today, the island’s marine resources are intermittently exploited by local fishing parties from Aitutaki and, to lesser extent, from Rarotonga; this has raised concerns because of the lack of monitoring of such visits. Also, some landowners have indicated that Manuae’s marine resources are showing signs of overfishing. Despite this, Manuae is now the only remaining island in the southern Cook Islands with very high densities of Tridacna clams.

Figure 41. Map of Manuae (19° 16’ 08.44” S, 158° 56’ 29.46” W) with yellow dots indicating the fore reef sites surveyed during this expedition. Green star indicates one of the fore reef sites established in 2005 (Rongo et al., 2005) that could not be resurveyed in 2013 due to rough conditions on the latter expedition. Taken from Google Earth.

Several reef surveys have been carried out on Manuae. The Ministry of Marine Resources conducted an assessment from 1994 – 1997 (Ponia et al., 1998a) to identify ideal sites for establishing Marine Protected Areas on the island, while the National Environment Service carried out a coral reef survey in 2005 to establish baseline information for the island (Rongo et al., 2005; see Figure 41). According to the 2005 report, Manuae’s fore reefs were depauperate of corals (e.g., 7% and 8% cover on windward and leeward exposures respectively). However, the complexity of reef structure — particularly on the leeward exposure — suggested that a much healthier and diverse reef community existed

55 here in the past, possibly destroyed by COTS outbreaks (Figure 42). A recent survey in 2013 (Rongo et al. 2013), showed a 30% increase when compared to 2005 (Rongo et al. 2005) indicating that Manuae’s reefs have been recovering well (Figure 43 & 44).

a b

c d

Figure 42 a & b) Acropora schmitti, one of the most common coral species on the shallow fore reef slopes of Manuae; c & d) Astreopora expansa, a hard coral found dominant on the steeper reef slope areas and only common on Manuae, Takutae, and Mitiaro. Photos taken by Teina Rongo.

90 Mean; Whisker: Mean±0.95 Conf. Interval Hard coral 80 Pavement 70 CCA 60 50 40 30 20

Average percent cover (%) percent Average 10 0 Site 1 (2005) Site 1 (2013) Site

Figure 43. Comparison of the average percent cover of hard coral, pavement, and crustose coralline algae (CCA) from one fore reef site surveyed in Manuae in 2005 (Rongo et al., 2005), and 2013 (Rongo et al., 2013).

Figure 44. Left: High densities of the small giant-clam (Tridacna maxima) were observed within Manuae’s lagoon; photo taken by Teina Rongo. Right: Aggregates of the purple queen anthias (Pseudanthias pascalus; photo taken by Graham McDonald). Both species used to be common on other islands in the Cook Islands.

Because the prevailing ocean current around Manuae is westward (towards Aitutaki), it was suggested that Manuae is a potential source population for Aitutaki, and its establishment as a Marine Protected Area may be critical for the recovery of Aitutaki’s reefs (see Rongo et al., 2005).

3.3.3.11 Takūtea Takūtea (Figure 45) is a small sand cay island (19°48’ S and 158° 17’ W), located 22 km northwest of Atiu. The island has a land area of around 1.2 km2 with a maximum elevation of around 6 m above sea level. The island is surrounded by a narrow and shallow fringing reef flat often exposed during low tide. Takūtea is one of two uninhabited islands in the southern group, considered an important nesting ground for turtles, is an Important Bird Area, and a wildlife sanctuary. Administratively, the island is considered part of Atiu and is owned equally by all inhabitants. Currently, the 57 wildlife sanctuary is administered by a Trust consisting of the traditional leaders of Atiu, with the High Chief Rongomatane as the chairman of the Trust; visits to the island have to seek the permission of the trustees. Although marine-related information on Takūtea is limited, a survey was conducted in 1998 by the Ministry of Marine Resources (MMR; Ponia et al., 1998c) to identify and quantify common reef resources on the island. This survey was commissioned by the Takūtea trustees to provide an estimate of a sustainable harvest quota for the main exploitable marine resources (i.e., Tridacna maxima) as overfishing was becoming a concern. Coincidentally, the MMR also facilitated the introduction of the trochus (Tectus niloticus) to the island in hopes that these will establish and serve as reserve stock for the island of Atiu. In 2013, Rongo et al. (2013) surveyed the fore reef communities, where a total of four sites were established (Figure 46).

Figure 45. Google Earth map of Takūtea (19° 48’ 45.93” S, 158° 17’ 18.57” W) with yellow dots indicating the sites surveyed during this expedition.

90 Mean; Whisker: Mean±0.95 Conf. Interval

80 Pavement CCA Hard coral 70

Average percent cover (%) cover percent Average 20

0 Tak 1 Tak 2 Tak 3 Tak 4 Site

Figure 46 Average percent cover of pavement, crustose coralline algae (CCA), and hard coral from four fore reef sites surveyed in Takūtea in 2013.

3.3.3.12 Atiu Atiu (Figure 47) is an uplifted makatea island located at latitude 19°58ʹ S and longitude 158° 06ʹ W, about 23 km southeast of Takūtea and around 200 km southeast of Aitutaki. Atiu is the biggest (27 km2 of land area) and the highest (72 m) of the Ngaputoru islands, which is dated around 8 - 9 million years old. Atiu has a narrow fringing reef with the widest reef flat area located on the southern exposure of the island (~ 120 m wide). In 2011, there were less than 500 people living on Atiu (Cook Islands Census, 2011), with the population declining since 1996 from migration to Rarotonga and beyond for job opportunities. While people on Atiu still practice a subsistence lifestyle, Atiu is one of the islands in the southern group that occasionally have reported cases of ciguatera poisoning from consuming Acanthurids (i.e., Ctenochaetus striatus). Notably, the first cases of ciguatera poisoning in the southern Cook Islands were reported from Atiu in the early 1980s (Losacker, 1992). According to locals, these poisonings tend to occur from consuming reef fishes caught on the leeward exposure of the island, particularly around the harbour site.

To date, information on the coral reefs of Atiu, particularly on the fore reef, is scant. Although the Ministry of Marine Resources has carried out an assessment of exploitable reef resources on Atiu in 1998 to gather information on their abundance and distribution (Ponia et al., 1998d), the assessment was limited to the reef flat areas of the island.

Figure 47. Google Earth map of Atiu (19° 59’ 37.28” S, 158° 06’ 56.88” W) with yellow dots indicating the sites surveyed in 2013.

3.3.3.13 Mitiaro Mitiaro (Figure 48), located at 19º 52’S 157º 41’W, is one of three sister islands in the southern group that includes Ma’uke and Atiu, with the three commonly referred to as Ngaputoru. This sunken island, dated around 12.3 million years old, was uplifted by tectonic activity associated with the formation of Rarotonga. During this period of uplift, the raised coral island, or makatea, reached a maximum elevation of around 11 m. The reefs of Mitiaro are fringed with places partially overlain by a sequence of late Pleistocene reef limestone. The total land area of the island is approximately 22 km2 and the circumference of the bench reef is approximately 18 km. Mitiaro has a population of under 200 people, residing mainly in the village of Taka`ue. To date there has been limited amount of marine research that has been conducted on Mitiaro. In 1998, a baseline assessment was carried out by the Ministry of Marine Resources (Ponia et al., 1998b) to quantify exploitable marine resources on the reef flat area. In 2002, a coral reef assessment was conducted on the fore reef (Lyon, 2002) as part of an Environmental Impact Assessment undertaken by the National Environment Service for a proposal by Government to upgrade the harbour. A total of six sites were surveyed on Mitiaro in 2013 (Figure 49); this survey added to the baseline information for the island (Figure 50).

Figure 48. Google Earth map of Mitiaro (19° 51’ 52.96” S, 157° 42’ 10.87” W) with yellow dots indicating the sites surveyed during this expedition. Site 3, 5, and 6 were established in 2002 (Lyon, 2002) and were revisited in 2013.

90 Mean; Whisker: Mean±0.95 Conf. Interval

80 CCA 70 Hard coral Soft coral Pavement 60

Average Average percent cover (%) 20

0 Ati 1 Ati 2 Ati 4 Ati 5 Ati 6 Site Figure 49. Average percent cover of crustose coralline algae (CCA), hard coral, soft coral, and pavement from six fore reef sites surveyed in Atiu in 2013.

Figure 50. Large colonies of Pocillopora spp. were common on the leeward exposure of Atiu. These colonies may have survived previous COTS outbreak due to the presence of Trapezia crabs that have been known to defend its host colony from COTS. The colony pictured was measured at around 2 m in diameter. Photo taken by Graham McDonald at Site 6 on the leeward exposure of Atiu.

3.3.3.14 Ma’uke Mauke (Figure 51) has several similarities to Atiu, Mitiaro, and Mangaia in that they are upraised coral islands surrounded by a narrow fringing reef with limited access through the reef. They all have two main habitat type (i.e., reef flat and fore reef). As a result, the diversity and abundance of fish and invertebrates are relatively low. While agriculture was an important industry from the 1970s to the early 90s that was exported to Rarotonga, however these came to a halt due to the moderate supply and strong competition from other countries. Today, small scale activities such as handicrafts, agriculture exports, and a limited tourist industry contribute to the islands’ economy, with the majority of people relying on government employment. In addition, subsistence agriculture and fishing still remain an important part in supporting their nutritional needs.

Figure 51. Google Earth map of Ma’uke (20º 09’ 38.34”S, 157º 20’ 34.89”W).

3.3.3.15 Palmerston Palmerston (Figure 52) is home to a small population of less than 100 people. The people of Palmerston rely heavily on a range of marine resources (i.e., reef fish, pelagic fishes, a variety of invertebrates, turtles) and sea birds. The lagoon has a maximum depth of 35 meters, and is largely an enclose reef. The islanders catch a wide range of fish and shellfish. At least one member of each household fishes or gleans daily. Hook-and-line fishing is conducted either from a boat beyond the reef or inside the lagoon, or by walking along the reef-flat and casting into surge channels. Ature (big eye scad), koperu (mackerel scad) and ungaunga (hermit crabs) are used for bait. Pelagic fishing is generally carried out on the leeward (NW) side of the island although some trolling occurs on the windward side. Spear guns are not widely used. The Palmerston Island Council, and fishermen and women have expressed growing concern for the future of the parrotfish fishery, and occasionally put the parrotfish under partial ra’ui. Pa’ua, mainly Tridacna maxima, have recently been harvested for sale because of an increase in demand and price offered for them. Lobsters are captured all around the reef at night by hand, usually on rising tides on dark nights. The crayfish resource is believed to be small and vulnerable to heavy exploitation. Adult green turtles and, to a lesser degree hawksbill turtles, are occasionally captured at night. Commercial fisheries and in particular the parrotfish fishery are important to the local economy.

Figure 52. Google Earth map of Palmerston (18º 02’ 49.63”S, 163º 09’ 18.81”W).

3.3.4 Mesophotic Coral Ecosystems The Mesophotic coral ecosystems (Figure 53) are zones found at depths between 30 and 150 meters where sunlight is limited. For the Cook Islands, these ecosystems are poorly known, yet, like shallow coral reef ecosystems serve as essential fish habitats for some economically and ecologically important fish species that use these areas for spawning, breeding, feeding, and growth to maturity. The majority of observations and data are from SCUBA diving expeditions from 1989 to 2012, which focuses on fishes (Pyle et al., 2019).

Figure 53. A typical mesophotic coral ecosystems in Rarotonga at 100m plus depths hosting antipatharian and gorgonian corals, sponges, and other encrusting invertebrates, and fishes. (Photo taken from Pyle et al., 2019)

3.4 Current condition and trends of populations of species and groups of species 3.4.1 Macroalgae Macroalgae are seaweed visible to the naked eye on reefs. Like all marine plants, they are autotrophic organisms that produce complex organic compounds (such as carbohydrates) from simple substances available in the environment using energy from the sun. While seaweeds are an essential part of the marine ecosystem, they are often overlooked when compared to their more conspicuous neighbors such as corals, fishes, and molluscs. Yet, they are an important source of food for a large number of marine organisms and humans. They also host useful compounds that can be extracted for use ranging from cosmetics, medicine, to preservative in the food industry. Earlier studies of macroalgae in the Cook Islands is very limited. Dickie (1877) recorded 21 species from Mangaia, while Cranwell (1933) recorded 4 species from Manihiki. Subsequently, Chapman (1977), recorded 24 species (1 Cyanophyta, 8 Chlorophyta, 9 Phaeophyta, 6 Rhodophyta) from Rarotonga. The most recent study was conducted by N’Yeurt (1999) on Rarotonga and Aitutaki, where he recorded over 58 species representing 43 genera (3 Cyanophyta, 14 Chlorophyta, 9 Phaeophyta, 17 Rhodophyta); the marine flora of the northern group has yet to be investigated. Considering that primary productivity is higher in the northern Cook Islands (due largely to its proximity to the equatorial upwelling), unique species may be found.

3.4.2 Benthic microalgae Benthic microalgae are microscopic plants which grow on a variety of habitats and substrates including sediment and pavement. Some are epiphytic in nature where they are found on a variety of macroalga or they can also be found in the water column. Microalgae play an important roles in primary production and nutrient dynamics (Heil et al, 2004). The biomass of benthic microalgae is typically several orders of magnitude higher than that of plants in the water column (phytoplankton; MacIntyre et al, 1996). Although very little is known about these species with regards to their taxonomy and distribution throughout the Cook Islands, the Ministry of Marine Resources has examined and monitored a few species of microalgae mainly those responsible for ciguatera poisoning in the 1990s. Subsequent studies have focused largely on these ciguatoxic species (e.g., Smith et al., 2016; Rhodes et al., 2017).

3.4.3 Corals Corals are perhaps the most important invertebrate used in marine monitoring as indicators of reef health. Since the early 1990s, marine surveys began in the Cook Islands especially for Rarotonga and Aitutaki (e.g., Miller et al, 1994; see also Rongo et al, 2014 and reference therein). To date, the number of coral species remain unresolved for the Cook Islands considering the difficulty with skeletal identification methods and the opportunity to travel to the outer islands. Recent genetic approaches to taxonomy are currently examining some of the genera (i.e., Acropora). Yet, corals are experiencing a diversity of stressors that are likely to determine their survival in the future.

3.4.4 Other invertebrates There are numerous species of invertebrates other than those mentioned in this section that are not assessed. While some exploitable species (e.g., sea cucumbers, urchin, giant clams) have been monitored over the years through the Ministry of Marine Resources (e.g., Raumea et al., 2000; Raumea and Makikiriti, 2001; Raumea et al., 2013), the status of many of them are unknown.

3.4.4.1 Crabs Edible crabs are an important food source for our Pa Enua including for some people on Rarotonga. The most sought-after of the crabs is the largest of them all, the unga-kaveu or coconut crab, Birgus latro. The unga-kaveu is slow-growing — taking 7-12 years to reach sexual maturity — and can live up to 40 years old. They are nocturnal omnivores and prefer coconut meat (McCormack, G, 2007), living close to the coast and spawning occurring usually during full moon. They also live inland close to water sources (Matamaki et al, 2016). It takes around 20 years for unga- kaveu to grow to edible size. Other edible crabs include the tupa (mud crab, Cardisoma carnifex). Tupa is commonly found along mudflats in Aitutaki along the coastline and on some parts of Rarotonga where there are mudflats. There are also other edible crabs such as the ‘opaki (Convex Pebble Crab, Carpillus convexus) and mānia (Spotted Pebble Crab, Carpillus 66 maculatus), found on all reefs of the Pa Enua. There are also the delicacies from the island of Ma’uke – the pāpaka tuapuku (Hump-backed Shore Crab, Plagusia tuberculate) and the pāpaka toetoe (Flat-Rock Crab, Percnon planissimum); both crabs are found on other islands in the Cook Islands, but because the Ma’uke community is known for harvesting these crabs for their families, this is why reference is made to this particular island. There are also the varo (Zebra mantis shrimp, Lyslosquilla maculata), found mainly on Aitutaki in the nearshore lagoon environment in muddy sand. Not much attention has been placed on the conservation of the other edible crabs, but they are worth mentioning as they form part of the food security resources of the Pa Enua and are found in the Marae Moana. The unga-kaveu, however, because of the time it takes to grow to a decent edible size, communities — especially in the northern group — have put into place measures to ensure its sustainability. Under the Pukapuka and Nassau rāhui programme, unga-kaveu have a long-term conservation program where protection of the crab starts after the young crabs starts to move onto the land. The community’s conservation practice prohibits burning of bush and dry coconut fronds and waste as these are places where young coconut crabs would be sheltering. Pukapuka have laws that are enforced by chosen rangers on their island, and because the system has been in place for many centuries, residents understand the benefits of their laws and compliance is maintained (see Munro, 1996). When it is time to harvest the unga-kaveu, each family member from young to old will have a share. Penalties for breaking the law will see an adult treated as a child indefinitely — not only in regards to receiving the same share as a child, but also in behaviour from other adults (Teki’i Lazaro, pers. comm). Other islands in the northern group have tried to follow the Pukapuka/Nassau program, but have not been as successful. Surveys in the Pa Enua of Ma’uke (Matamaki et al., 2016) and Mitiaro have been conducted to determine population size structure and distribution. The survey — a joint SPC and NES initiative — also provided an estimate of coconut crab abundance on each island and trained people to continue the survey for monitoring purposes. Results indicated signs of over-exploitation, and recommendations included regulations to be prepared and rā’ui areas, in the case of Ma’uke, to be increased.

3.4.5 Sharks and rays The 2013 listing of five species of sharks and all manta rays by the Convention on International Trade in Endangered Species (CITES) leaves no doubt that elasmobranch conservation is a major global concern (https://www.wcpfc.int/node/28674). For example, the thresher shark species suffer from low productivity and high susceptibility to longline fishing compared with most other pelagic sharks. In addition, the bigeye thresher shark (Alopias superciliosus) has the widest distribution, yet is the most vulnerable of the three thresher species to fishing pressure in the Pacific. Silky shark (Carcharhinus falciformis) is another species that has seen decline around the world, and has prompted the IUCN to reassess its conservation status to vulnerable in 2017. Similarly, rays are globally threatened through both high levels of bycatch and targeted exploitation and they are currently at risk of extinction. Improved

67 management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery. Unfortunately, the Cook Islands have limited data on sharks and rays and many of the information are anecdotal accounts from fishers throughout the islands (Rongo and Dyer, 2014). While those in Rarotonga and Aitutaki have suggested a decline, those in the northern islands have suggested an increase especially with sharks. In 2013, the Cook Islands established the world’s largest and strictest shark sanctuary; a minimum fine of $73,000 is given to any vessel found possessing any shark parts within Cook Islands waters. Although research on sharks in the Cook Islands is underway, information on rays is very limited. There are 18 different species of shark found in Cook Islands waters. The more common sharks include the white-tip reef shark, the black-tip reef shark and the grey reef shark. Other sightings include hammerhead sharks, oceanic white-tip sharks, tiger sharks and whale sharks.

3.4.6 Marine turtles ‘Onu or turtle is a very important resource in both the northern and southern Cook Islands, but more so in the northern group as a sought-after food source. Information provided in the Cook Islands Biodiversity Database showed that the two most common species in the Cook Islands are endangered turtles — ‘Onu kai or green turtle, Chelonia mydas, and the critically endangered ‘Onu Taratara or hawksbill turtle, Eretmochelys imbricata. Locally, people are eating less turtle meat, mainly because of increased awareness programs over the past decades on the declining state of turtles worldwide. It is apparent over the past two decades that there has been a move away from this food source and turtle meat is no longer served at feasts in the northern Pa Enua. Turtle research has been conducted in the Cook Islands since the 1970s (Anon., 1978). More recently, the Cook Islands Turtle Project (CITP) collected tagging and nesting information to determine current distribution, abundance and population status since 2009, and subsequently added to the Turtle Research and Database System (TREDS) of SPREP (Trevor, 2009; Siota, 2010; White, 2011, 2012; Bradshaw & Bradshaw, 2012; Bradshaw, 2013; Ischer et al., 2015). According to Ischer et al. (2015), “nesting activity, turtle sightings and/or anecdotal evidence has been reported in Aitutaki, Manihiki, Nassau, Palmerston Atoll, Pukapuka, Rakahanga, Suwarrow, Tongareva, Manuae, Rarotonga and Ma’uke.” Turtle conservation efforts include education and community outreach initiatives. The CITP has identified that aside from people eating turtles, turtle nests are also prone to wild pigs interference as is the case in Manihiki and Penrhyn; on Manihiki, some areas known to be turtle nesting areas are also sand mining sites.

3.4.7 Seabirds The avifauna of the Cook Islands include a total of 50 species, of which six are endemic, one has been introduced by humans, and three are rare or accidental. Ten species are globally threatened. Birds described from subfossil remains that became extinct as a consequence of human settlement of the islands and the introduction of exotic mammals include the Mangaia rail (Gallirallus ripleyi) and the Mangaia crake (Porzana rua) (Staedman, 1986).

3.4.8 Cetaceans For over 20 years of whale research in the Cook Islands, our understanding of humpbacks (Megaptera novaeangliae) migration patterns have improved. Photo-identification and genetic studies of humpbacks have identified at least five discrete breeding populations in Australia and Oceania: western Australia (D), eastern Australia (E (i)), New Caledonia (E (ii)), Tonga (E (iii)), French Polynesia and the Cook Islands (F) (Franklin et al., 2014). These breeding stocks have migratory connections to feeding grounds in the Antarctic (IWC 1998). Although there is no current abundance estimate, the Cook Islands aggregation of humpbacks appears to be small and transient – the Cook Islands is not a primary migratory destination, but rather a part of a migratory corridor used by one or more breeding stocks – through photo-identification matches, connections were identified with other areas especially Tonga (e.g., Garrigue et al. 2002). While whales ultimately migrate to their feeding grounds in Antarctica, tagging studies showed that from Rarotonga, humpbacks migrate west to northwest towards Samoa and American Samoa before tracking the Tonga trench south (Hauser et al., 2010). Tagging results reinforced the connection between the Cook Islands and Tonga, as well as with Samoa/American Samoa. To date, photo-identification comparisons have found 11 matches between the Cook Islands and Tonga, and one with American Samoa (Hauser et al., 2010; Garrigue et al., 2011). In support, genetic research in 2007 (Olavarria et al.) showed Cook Islands whales to be nearly indistinguishable from those of Tonga. In 2007 the six Rarotonga whales with satellite tags all departed to the west or northwest (Hauser et al. 2010, Horton et al. 2011), which further supported the link that Cook Islands’ whales have with the Tonga whale population. In 2015, after 18 years of monitoring, there had been only two resightings in the Cook Islands (Hauser, unpublished), which showed that whales rarely reuse the corridor. According to the Cook Islands Whale Research Center for Cetacean Research & Conservation website, the following species are commonly observed in the Cook Islands: Humpback Whale (Megaptera novaeangliae) Sei Whale (Balaenoptera borealis) Blue Whale (Balaenoptera musculus) Dwarf Minke Whale (Balaenoptera acutorostrata) or Antarctic Minke Whale (Balaenoptera bonaerensis) Sperm Whale (Physeter macrocephalus) Killer Whale (Orcinus orca) Short-Finned Pilot Whale (Globicephala macrorhynchus) Peale’s Dolphin (Lagenorhynchus australis) Cuvier’s Beaked Whale (Ziphius cavirostris) Blainsville’s Beaked Whale (Mesoplodon densirostris) Spinner Dolphin (Stenella longirostris) Striped Dolphin (Stenella attenuata) Fraser’s Dolphin (Lagenodelphis hosei) Melon-Headed Whale (Peponocephala electra) Risso’s Dolphin (Grampus griseus)

3.5 Assessment summary – Biodiversity This assessment is based on two assessment criteria: • Habitats to support species. • Populations of species and groups of species.

3.5.1 Habitats to support species Some inshore lagoon habitats on two of the islands (i.e., Rarotonga and Aitutaki) have deteriorated, caused mostly by reduced water quality and rising sea temperatures. This is likely to have affected species that rely on these habitats. Little is known about the state for most islands. Also, many of the habitats have little to no information to determine their state.

3.5.2 Populations of species and groups of species With limited data available, it is difficult to suggest with confidence the state of most of the species and group of species in the Cook islands. Populations such as sharks, seabirds and marine turtles, are still poorly understood and there are concerns that with human activities, climate change and declining environmental conditions, many of these species may not cope. In addition, many species are yet to be discovered and for others, very little is known about their status.

3.5.3 Overall summary of biodiversity While many of the habitats and species and group of species seems to be intact, more research is needed to understand their state. The lack of information means the assessment of many habitats and species or groups of species is essentially based on limited evidence and anecdotal information. Key gaps in knowledge include understanding of many of the reefs in the outer islands due to limited access; taxonomic issues are also a concern because it is difficult to study a species without a name. Biological and ecological information are also lacking on many species (e.g., dolphins).

4. HERITAGE VALUES

4.1 Background The assessment of heritage values is not a specific requirement of the Outlook Report under Section 34 of the Marae Moana Act 2017, however, as with its neighboring Pacific Island countries, the Cook Islands indigenous people have a very strong link with their lands and the sea that surrounds them. It is a way of life that includes plants, animals and the environment both on land and in the sea, making nature inseparable from cultural identity. It is to be noted that heritage values are strongly linked to our way of life which is directly linked to how we use our terrestrial and marine resources. With the changing lifestyle in the Cook Islands where people are now more dependent on imported foods, especially on the more developed islands of Rarotonga and Aitutaki, cultural values are at risk. This assessment of heritage values will attempt to assess the following: indigenous values, historic heritage, other heritage values, national heritage values, and natural heritage values. Each of the values is broken down into groups to help with the assessment. The groups are:

. Indigenous values: cultural practices, observances, customs and traditions; sacred sites, sites of particular significance, and places important for cultural tradition; stories, songs, tattoos, chants and language; and indigenous structures, technology, tools and archaeology. . Historic heritage values: historic voyages and ship wrecks; World War II features and sites; and other places of historic significance. . Other heritage values: social heritage values, aesthetic heritage values, and scientific heritage values. . National heritage values: natural beauty and natural phenomena; major stages of the Earth’s evolutionary history; ecological and biological processes; and habitats for conservation of biodiversity, integrity, and benchmarking outstanding universal value . Natural heritage values: See Biodiversity.

It is important to note that in the Cook Islands, a person of Cook Islands descent have land rights and therefore are strongly linked to the indigenous heritage values from where his or her ancestors come from in the Cook Islands. If the person is from Aitutaki and living in Rarotonga, normally he or she will refer to himself/herself as an Aitutakian and may wish to participate in community activities of the Aitutaki community on Rarotonga. With the inter-marriages between the different people from each island, a person may have more than one community group and this nowadays is not uncommon. The indigenous values of each person may be expressed by way of how much the person has learned from their parents and where they grew up and this includes traditional practices, observations, customs, traditions, beliefs or history.

4.2 Current state and trends of Indigenous heritage values Indigenous heritage values recognize the customs and traditions of each of the inhabited islands of the Cook Islands. The customs and traditions of each island are kept by the Tumu Kōrero (traditional knowledge holders) or Ta’unga (traditional knowledge practitioners) under the umbrella of the traditional leaders. Traditionally, a Ta’unga is a part of a group known as the Vaka Ta’unga or a group of specialist practitioners. For example, Ta’unga Vairakau refer to traditional medicine practitioners, and Ta’unga Tarai Vaka are canoe or vaka builders. Our Tumu Kōrero and Ta’unga express customs and traditions through their relationships with the people as well as their beliefs, knowledge, teachings, language, songs, symbols, and ways of living, and use of marine and terrestrial resources. Practicing traditional cultural practices in the Cook Islands maintains the knowledge. The Traditional Knowledge Act 2013 recognizes an ‘Are Kōrero or house of knowledge on each island. The ‘Are Kōrero of each island is a place where knowledge holders meet and where the knowledge is kept and passed on to the next generation. In view of our changing lifestyle where our knowledge is at risk of being lost, or stolen, the Act recognizes the ownership of knowledge and has set a mechanism to register any traditional knowledge. For those that still have a strong link to the land, especially those in the Pa Enua, their way of living has kept them close to the land and sea, and therefore the people still practice some of our customs such as the use of the ‘arāpo or traditional calendar based on the moon phases — used to plan fishing and agricultural activities. Also, for those in the Pa Enua, being away from the main island of Rarotonga where the use of modern medicine is associated with trained medical practitioners, the Pa Enua still retain their traditional medicine practitioners as they are closer to them than they are to the doctors trained in Western medicine. In this section, cultural values are grouped in the following broad components: . Cultural practices, observances, customs and traditions . Sacred sites, sites of particular significance and places important for cultural tradition . Stories, songs, tattoos and languages . Indigenous structures, technology, tools and archaeology While this section presents information on cultural values under discrete headings, in reality, they cannot be separated. All values are connected and interrelated and the descriptions of each value should be viewed in this context.

4.2.1 Cultural practices, observances, customs and lore The practice of selection and investiture of a chief is widely practiced on islands that are represented in the ‘Are Ariki (Council of High Chiefs) or are a part of the Koutu Nui (Council of sub-chiefs). Each Matakeinanga or clan (in the case of an Ariki or High Chief) or sub-clan (in the case of a Mata’iapo or sub-chief) will go through the investiture ceremony on the Marae (sacred site) of the Ariki or Mata’iapo once the chiefly family has chosen the member of their family to take the title. This practice still occurs today and it is a prerequisite to enter the ‘Are Ariki or the Ko’utu Nui. The relevance of this practice to the Marae Moana is that the chiefs have traditional power over the resources within the 72 coastal waters and are responsible for the rā’ui of resources in the nearshore marine environment. The Ariki and Mata’iapo of each island overlook the functions of the ‘Are Kōrero on those islands. Rā’ui, the traditional conservation practice of setting aside areas of a particular resource — whether on land or sea to help replenish supply — is still being practiced today. On Rarotonga, sections of reefs and lagoons are placed under rā’ui and managed by the Chiefs upon which the area is located. This system of management is not as effective as before because of the inadequate understanding amongst the community of how the system works. In addition, the fragmentation of communities into a variety of social networks has also led to limited participation in and awareness of the declaration of rā’ui; education and awareness programs about the location of rā’ui and the rules associated with them are also scant (Jacqueline Evans, pers. comm.). Nonetheless, it is still being practiced as not everyone is disrespectful of this age-old practice. Rā’ui is common in the northern Cook Islands because of the limited supply of certain resources (e.g., unga-kaveu or coconut crabs).

4.2.2 Sacred sites, sites of particular significance and places important for cultural tradition Marae or sacred sites fall under a number of groups: the marae of a high Chief or sub chief (Mata’iapo and Rāngatira) where their investiture ceremony takes place, or a sacred site where important ceremonies are held for the island. There are also the paepae, which is a marae where a high chief or someone that is important to the Matakeinanga lived. The relevance of this to Marae Moana is that, usually, for those high chiefs and sub chiefs (in the case of a sub-chief, Mata’iapo Tutara), the mana (power) to lift a rā’ui stems from the chief’s marae or his paepae. The Marae ‘Ōrongo is a chain of marae on most islands and is commonly located near the main landing passages of each island. The islands where the remains of this type of marae are still evident are Ma’uke, Atiu, Aitutaki and Mangaia. It is widely believed that this provides evidence that these islands were closely linked during pre- Christianity times and the chiefs of those islands communicated with each other. Tu’oro, commonly known as Blackrock, on Rarotonga is said to be where the spirit of an important person leaves to go back to Avaiki when they pass on. The belief was, as with that of our Polynesian neighbors, we don’t go up to heaven, instead we go down to Avaiki. There are other similar sites in the Cook Islands, but more work is required to compile the information on other locations. It is understood that these sites are all near shore. Te Rua Mangā is the name given to the famous needle-like peak in the middle of the island of Rarotonga, which is more commonly known as ‘The Needle’. Traditional knowledge says that the peak is used by fisherman to align themselves to a mangā (snake mackerel) fishing ground. There are many such landscapes with significance that surround Rarotonga as well as on the other islands in the Pa Enua. For some islands, passages are named after a major historic event or places where legendary characters once stood. For example, today there is a headland on the northern coastline of Enuāmanu (Atiu), where the renowned warrior Taratoa left the island to join another legendary warrior Marouna to fight the aitu (warriors) in Aitutaki. This place is called Te-Tau-O-Tara or “the headland of Tara”.

This illustrates how places along coastlines of islands have been named, and, for the Atiuans, it helps them to remember their heritage. Wetlands have a special significance for nearshore marine environments as it acts as a filter of waters from inland catchments flowing towards the sea. They are usually located inside of the coastal zone, supporting a wealth of plants that are used by traditional medical practitioners for making medicine. It is also a habitat for freshwater eels that help aerate wetlands as they burrow through the wetland substrate. For decades, these areas have been extensively modified by the indigenous Māori through the planting of taro using the pa’i taro or taro patch method of planting. When early Polynesians arrived on the islands, they used the wetlands by manipulating water flow and planted wetland taro. Wetlands are significant areas to Marae Moana because of its influence on the nearshore marine environment, and also for its biodiversity which supports a big part of our heritage. Foreshore is defined as the area 30 meters inland of the mean high water mark, and 5 meters from the center of streams. Like wetlands, the foreshore supports a variety of biodiversity useful to our traditional living. It is also our first line of defense during times of high seas and severe cyclones. Traditionally, our ancestors did not have permanent housing in this area because of these reasons; they respected this area and the services provided. Fish traps or sites of fish traps are also important areas of Cook Islands Māori heritage. It provides information on fish species caught, current flow as well as general information about the area. Some fish traps are named according to who built it, the name of the nearby motu, or the fish that was being caught. Because of changes effected by climate change, some of these sites are no longer used but the names are still being used to identify one’s location in the area; such is the case in Manihiki where some of the fish traps are no longer used.

4.2.3 Stories, songlines, and languages With increased Westernization over time, the Cook Islands Māori language is one that is at risk of no longer being used. If careful measures are not quickly put in place, the cultural heritage of the indigenous people is very much at risk. The annual Te Maeva Nui event which celebrates the Cook Islands Constitution Day in the week leading up to August 4, is a platform that encourages keeping the culture alive. Songs, chants, stories and legends are a feature of Te Maeva Nui where songs relevant to the theme of the event are re-sung or new ones composed. In 2005, a song competition was organized for World Turtle Day and World Environment Day, which resulted in new songs composed for turtles and for the local environment. The lyrics incorporated old sayings and old names for places such as Moana-Nui-O-Kiva, or what is better known as the Pacific Ocean. The art of tattooing has in recent years made a comeback after almost 100 years of not being a feature of our heritage due to missionary influence in the Cook Islands linking tattoos to people who have been in prison. The reemergence of tattooing is perhaps linked to the regional, if not international, trend in fashion. This has encouraged local tattooists to conduct research on Cook Islands motifs, and subsequently incorporating these symbols into their

74 designs. For most Cook Islanders, it is no longer just about a pretty or unusual picture; tattoos have a personal story to tell, which is normally linked to one’s family or ancestry. There are many examples of stories told on each of the islands that reflect the origin of the names of their islands, and all of them have thing in common: the person who named the island sailed across the sea and discovered the place. Story has it that Manihiki was fished out of the ocean by the demi-god Maui. In the case of Atiu or Enuāmanu, a warrior by the name of Māriri-tutu-a-manu arrived from Avaiki and landed on the island now called Takūtea just before nightfall. After he landed, he prepared to go fishing and the first fish he caught was a white kū, and therefore he named the island after his catch: taku kū tea, my white kū.

4.2.4 Indigenous structures, technology, tools and archaeology For the Cook Islands, there is limited information on indigenous structures, and it is the understanding of the authors of this report that these would be naturally-formed or become part of the coastal landscape. Notably, information from each of the Pa Enua needs to be compiled to identify any structures that may exist; the Tumu Kōrero of each island should be consulted. As an example, a volcanic rock outcrop on the makatea of Ma’uke is called Te-Tūtau-o-Tangi’ia (anchor of Tangi’ia’s vaka) and located almost in the middle of the island. Legend has it that Tangi’ia while on the run from the warrior Tutapu, left the tūtau on the island. There may be other structures on other islands and along the coastline relevant to heritage that should be captured under the Marae Moana Outlook report. As mentioned in Section 4.2.2, the indigenous people on each of the inhabited islands of the Cook Islands did not live or build permanent structures on the coastline because of the effect of high seas and surges during times of cyclones and extreme weather. However, they had the technology to make items such as paiere (dug-out outrigger wooden canoes), ‘īnaki or fish traps from woven coconut husks, woven baskets from coconut fronds of either green or dried fronds, and fish spears from taiki (the hard core of iron wood or the ‘ano), fish hooks from parau (black-lipped oyster; Ministry of Cultural Development, 2018) and ariri (Turbo spp.) shells (Allen, 1992). Of note is the 800-year-old fish hooks on display at the National Museum on Rarotonga. The indigenous people also developed fishing techniques for catching tuna using plant materials to package crushed bait while using volcanic rock as a sinker to take the bait down to the required depth (Anon, 2000). They developed many other tools and technology such as the hand nets made from coconut sennit used for māroro fishing (Anon, 2000). In the last 30 years, there has been a lot of interest in the building of traditional ocean-going canoes, and one of the Cook Islands very own, the late Sir Thomas Davis and also former Prime Minister, was at the forefront of this development. A former National Aeronautics and Space Administration (NASA) researcher, he first built the Takitumu, a double-hull vaka following the Samoa alia. Takitumu would sail from Rarotonga to Tahiti, onto Hawai’i and back to Rarotonga. Later, he built the vaka, Te Au O Tonga, which later became the model for seven ocean- going vaka that sailed around the world and were built by the Okeanos Foundation in 2009 (Okeanos Foundation, 2018) that sailed

75 around the world. Marumaru Atua is the name of the newest Cook Islands vaka that was part of the fleet of seven new vaka.

4.3 Current state and trends of historic heritage values 4.3.1 Historic voyages and shipwrecks The early ‘great fleet theory’ (Smith, 1921), suggested that a single wave of seven canoes colonized New Zealand around AD 1350. It is now generally accepted that multiple waves of migrations occurred, originating from the East Polynesian ‘homeland’ (Rolett, 2002), with the first canoe arriving in New Zealand around AD 1280 (Wilmshurst et al., 2008). There is a famous site on Rarotonga — famous among Polynesians — which marks the departure of the seven canoes of the ‘great fleet theory’ at Avana passage in Ngatangi’ia, seaside across from Ngatangi’ia church. Legend has it that the seven canoes — Aotea, Kurahaupō, Mātaatua, Tainui, Tokomaru, Te Arawa and Tākitimu — left from this point. Families on Rarotonga and in the Pa Enua have associated oral traditions and stories of this voyage in their family oral histories; there is a need to compile the information so that it is accurately recorded. The British ship, SS Maitai, is perhaps the most famous shipwreck in the Cook Islands, which can be seen to the west of Avarua Harbor in Rarotonga. The SS Maitai ran aground on Christmas Eve 1916, while on a voyage from San Francisco to Wellington (Wreck Site, 2018). After 101 years, the engine block is still visible, cemented to the reef and withstanding many cyclones over the years.

4.3.2 Other places of historic significance Other historic places that do not receive much attention include those found on Mangaia; the giant foot print of Moke, the son of Tavera, a giant supposedly the largest of the South Pacific, who stood at no less than 20 meters tall still remain today on the coast of Mangaia. On Motu Rakau in Aitutaki, is perhaps one of the most important archaeological site in the Cook Islands where ancient middens has provided researchers information about fishing practices in the Cook Islands (Allen, 1992). Other important archaeological site included Te Kainga of Rakahanga, which is the original settlement of Rakahanga before the arrival of the missionaries. On the island of Mauke, the look-out point at Anaiti was the site where Kea who is the wife of Paikea, the famous voyager who was part of the fleet that colonized New Zealand, wept and died waiting for Paikea to return. There are many more historic sites in the Cook Islands that needs to be protected especially from the impacts of climate change. Other sites are threatened by development. For example, the land Vairota in Avana on Rarotonga, is a historic land mark for the Cook Islands traditional voyagers, was sold to a foreigner for development (Cook Islands News, 2019a). These sites and their associated stories needs to be integrated into the local education curriculum for greater awareness among the local population.

4.4 Assessment summary — Heritage values 4.4.1 Indigenous heritage values Heritage values have not been assessed for the Marae Moana. There is a risk that traditional owners are disconnected from their cultural practices and customs, particularly on Rarotonga. The knowledge associated with indigenous heritage values are passed on to the next generation, and it is likely that knowledge has been lost or is at risk of being lost.

4.4.2 Historic heritage values Many of the historic sites in the Cook Islands are poorly known especially among the local population. For example, information of the SS Maitai in Avarua is poorly known among the local population.

4.4.3 Overall summary of heritage values Indeed there has been very little effort to protect places of historic significance in the Cook Islands. Most importantly, there is little effort to educate the indigenous people of these places. It is critical that historic sites and their stories are included in the school curriculum of the Cook Islands. There is also a need to properly assess the value of these site to help monitor trends in the future.

5. COMMERCIAL AND NON-COMMERCIAL USE

5.1 Background With the majority of the Cook Islands’ Exclusive Economic Zone of almost two million square kilometers covered by ocean, there are an abundance of commercial and non-commercial marine-related activities that have occurred, are occurring, or could potentially occur within the territorial waters ranging from fisheries, tourism, deep sea minerals exploration, marine transportation as well as a variety of related research. This chapter examines these marine-related activities.

5.2 Traditional use of marine resources The traditional use of marine resources include the following: food, arts & craft, construction, and medicinal. Tākiri pātuki, a traditionally fishing method that is carried out in the surf zone, is one method that has been practiced for centuries (Figure 54).

Figure 54. Tākiri pātuki, a traditionally fishing method that is carried out in the surf zone, is one method that has been practiced for centuries. These young girls are picture in Nikao fishing for patuki (Epinephalus spp.). Photo by Teina Rongo in 2009.

In the northern group, we see the use of the black pearl oyster shell (Pinctada margaritifera) for a variety of art and craft products (e.g., rito hats and fans; Figure 55). In addition, many of the cowry shells (e.g., Cypraea moneta) are used for making necklaces. Before the use of cement, a specific coral species called punga (Porites spp.) was used for making lime or locally known as ngaika for building concrete homes or for panting walls. Typically, a large number of punga are taken out of the lagoon or reef flat areas alive and are piled up in a pit to be burned for a few days. The end result of this process is a very white and fine powder of lime.

Figure 55. Rito hats (left top), fans (left bottom), and cowrie necklace (right) handmade from the island of Penrhyn in the northern Cook Islands by master weaver, Leida Tapu (https://www.facebook.com/leidatapucreations/). Photos provided by the Rongo family.

Some marine resources are used for medicinal purposes. For example, rori toto (Holothuria atra) and vana (Echinothrix diadema) have been used for the treatment of cancer (Ngapoko Marsters, pers. comm.; Figure 56).

Figure 56. Left: Rori toto or Holothuria atra. Right: Vana or Echinothrix diadema. Photos by Gustav Paulay.

5.2.1 Current state and trends of traditional use of marine resources The current state and trends of traditional use of marine resources is very limited.

5.2.2 Benefits of traditional use of marine resources The traditional use of marine resource can provide information that can help manage the target resource. These information include knowledge on the timing and location of spawning activities, and life history traits. Most importantly, it keeps indigenous people connected to their environment and aware of the status of their resources. For the most part, the use of traditional practices can help ensure that the health of a particular species remains healthy.

5.2.3 Impacts of traditional use of marine resources Traditional practices can have negative impact on resources and some have been outlawed in the Cook Islands. For example, the use of fish poison plants (e.g., barringtonia and derris plant) as a form of fishing has been banned by the National Environment Service Act (2003). Considering that important marine food resources over the last few decades have seen a noticeable decline (e.g., Rongo and Dyer, 2014), the long standing traditional practices by local residents to obtain marine resources may need to be examined. In particular, many fishing practices in the northern Cook Islands are timed around the spawning months of some species. For instance, the traditional fishing of hapuku (Epinephelus polyphekadion; Figure 57) in Penrhyn during the months of July to August when this species aggregates in large numbers can have a direct impact to the survival of this species, especially when their numbers have struggled to return over the last 20 years. In addition, the mass harvest of marine resources as gifts to families and friends or to sell, during the Constitution Celebrations can be problematic. In recent years, this has been particularly true for the pa`ua (Tridacna maxima), a species that has seen a drastic decline in its population throughout the Cook Islands over the last 20 years.

Figure 57. Hapuku or Epinephelus polyphekadion. Photos from the Cook Islands Biodiversity website.

5.3 Commercial marine tourism 5.3.1 Current state and trends of commercial marine tourism The total fisheries sector contributes over 6% to the country’s growth (GDP) and is the second most productive sector after tourism. Game and artisanal/coastal fishing component within this sector is presented in two time periods. Previous work estimated about $3.1 m of economic growth was attributed to subsistence and coastal commercial fishing (Gillet, 2007). The game fishing estimates are based on assumptions for 2011 and gives $2.4 m as the conservative contribution of game fishing activities and operations to the Cook Islands. Bearing in mind the aged estimates for subsistence and coastal commercial fishing, a conservative total of $5.5 m from coastal commercial/subsistence/game fishing is presented for this report as artisanal and game fishing contribution to economic growth in 2011. Though artisanal and game fishing operations compared with the other subsectors of the fisheries sector may seem small in terms of contribution into national accounts and visibility in the economy, the socio-cultural significance should not be understated. The demand for fresh fish remains an unsatisfied constant, and this fine balance of small fishers effort alongside the local longliners and the Pa Enua frozen and dried fish suppliers observes a very fine equilibrium supply and demand chain (Wichman, 2012). Slight negative shifts in catch will have harmful effects on our local fishers. In other areas, marine-based tourism activities are almost exclusively nature-based, with coral reefs and other marine life such as whales, marine turtles, and sharks as observed via lagoon tours, diving, snorkelling, fishing, sailing, and kayaking. Swimming, snorkelling, scuba diving and viewing animals are consistently popular tourist activities. The industry offers a wide range of tourism experiences, from cruise ships and live-aboard vessels to day trips on high speed catamarans, fishing charters and kayaking tours. Rarotonga and Aitutaki have a large number of giant trevally on their reefs. The giant trevally or ‘GT’ is a great sport fish with light tackle and many an angler experiences the thrill of this catch-and-release species. Fishing on Rarotonga is unique as the island only has a 36 km circumference around the reef, meaning fishing locations in nearly all weather conditions. According to the Cook Islands Government 2018/19 Half-year Economic and Fiscal Update, “total landed value of fishery catches decreased between 2014 and 2016 to $40.6 million, before recovering in 2017 to $55.3 million (Table 6). The decrease is largely due to change in methodology used by FFA in 2014 and 2016 to estimate catch values. The exchange rate of NZD to USD and Japanese Yen are also important factors”.

Table 6. Landed value of fishery catches ($m), taken from Table 4.8 in the Cook Islands Government 2018/19 Half-year Economic and Fiscal Update.

The Cook Islands Government 2018/19 Half-year Economic and Fiscal Update continues in identifying “the one domestic commercial fishing company, with three Cook Islands’ flagged vessels, operates in the southern Cook Islands waters, offloads its fresh catch at Rarotonga for sale in the domestic market and to be exported. In 2017, 286 MT of fish was unloaded from Cook Island’s domestic vessels in Rarotonga, compared to 179MT in 2016. The volume of exports increased from 15 to 25 MT over this period.”

5.4 Fishing 5.4.1 Current state and trends of fishing 5.4.1.1 Coastal fisheries & aquaculture Pacific Islanders have had a close association with their natural environment for millennia, relying on terrestrial and marine resources to sustain them. Coastal fisheries and aquaculture have been historically used for non- commercial, community and subsistence purposes, and more recently for commercial purposes such as the black pearl industry. Much local knowledge exists in the Cook Islands of these practices, which will be examined further in Chapter 3: Cultural and Traditional Use of Resources. The Cook Islands Ministry of Marine Resources summarizes many of the different fishing methods practiced in the Cook Islands and the different resources targeted by each method (MMR & SPC, 2000). Using the Western approach of quantitative analysis, the Secretariat of the Pacific Community (SPC) has supported much work in the region including the Cook Islands. A bibliography of the Cook Islands fisheries was generated in 1989 (Gillett and Tearii, 1989), and of Pacific Islands marine resources 2006 to capture much of their regional data collection efforts as well as other work conducted on respective islands (Gibert, 2006). Coastal fisheries surveys of finfish and invertebrates including socioeconomic assessments have been conducted on Aitutaki, Palmerston, Mangaia, and Rarotonga in the Cook Islands (Pinca et al., 2009) as part of a regional programme, CoFish and PROCFish/C, to collect baseline information on the status of reef fisheries to assist in its effective management (Pinca et al., 2010). The report examined the black-lipped pearl oysters (Pinctada margaritifera), topshell (Trochus niloticus), giant clams (Tridacna maxima), bêche-de-mer, and other invertebrates as well as finfish

82 production. Topshell and giant clam research including size and abundance assessments were also made by SPC in the Cook Islands (Adams et al., 1992; Nash et al., 1995; Chambers, 2007a, 2007b). Passfield (1988) examined tropical spiny lobsters in Rarotonga, and in the northern Cook Islands, Passfield (1996) described spawning aggregations of hāpuku (Epinephalus polyphekadion) in Penrhyn, which local fisherman would utilize to harvest these fish. The first coconut crab assessment conducted by the Cook Islands National Environment Service was on the island of Ma’uke in October 2015, where population size structure and distribution information was collected to estimate abundance (Matamaki et al., 2016). The Secretariat of the Pacific Community (SPC) also assessed outer reef fisheries in Aitutaki (Hume, 1976) and the ungakoa fishery in Aitutaki, Mangaia and Rarotonga (Lasi and Kronen, 2008). In 2008, a preliminary assessment was conducted on post-larval fish capture and culture on Aitutaki (Malpot et al., 2008); a bonefish sport fishing feasibility study was also carried out by SPC Aitutaki in the following year (Hamon and Blanc, 2009), which was identified as a good location to develop if strict conservations measures were put into place. Investigations into the pearl shell industry in the Cook Islands began in the 1950s (Noakes, 1959; Hynd, 1960), but would not be until 1982 that a family in Manihiki began this venture (Sims, 1993). Genetic and growth studies of P. margaritifera were conducted in the northern Cook Islands (Sims, 1994; Benzie & Ballment, 1994), as well as general research to support cultured pearl production in the Cook Islands (Sims, 1992a,b; Rowntree, 1993; Hine, 1998; Norton et al., 2000; Ponia et al, 2000). The commercial exploitation of aquarium fish in the Cook Islands was also an important source of revenue, which was established in 1988. One foreign-owned company was granted permission to operate on Rarotonga by the Cook Islands Government. This relatively small operation earned around NZ$80,000 at its initial stage in 1988 and in 1996 earnings were around NZ$240,000 per year (Bertram, 1996). There are five main fish taken from the Cook Islands, these include flame angel (35%), red hawkfish (30%), ventralis (15%), Scotts’ wrasse (7%) and lemonpeel angelfish (7%). With regards to over fishing of coastal resources, only some may be at risk of being overfish (e.g., Pa’ua in the northern islands and the parrotfish population of Palmerston). For the most part, people in the Cook Islands relying more on imported goods and marine resource consumption has declined along with fishing activities.

5.4.1.2 Offshore fisheries The Western and Central Pacific Fisheries Commission (WCPFC) is the central decision making body for management of tuna fishing in the Western and Central Pacific Ocean. Conservation and management measures (CMMs) of the Commission are legally binding and apply to all WCPFC members and the Convention area. Whereas members of FFA are from the Pacific Islands, members of WCPFC are FFA members and distant water fishing nations. WCPFC's current members include Australia, China, Canada, Cook Islands, European Community, Federated States of Micronesia, Fiji, France, Japan, Kiribati, Korea, Republic of Marshall Islands, Nauru, New Zealand, Niue, Palau, 83

Papua New Guinea, Philippines, Samoa, Solomon Islands, Chinese Taipei, Tonga, Tuvalu, United States of America and Vanuatu. The Western and Central Pacific Ocean accounted for 54% of the world's tuna catch in 2007 making tuna a key economic resource. Rarotonga and Aitutaki’s tuna longline fleet benefited from technical assistance provided by SPC (Beverly and Chapman, 1998). The distribution and the migration of pelagic fish species have been linked to multiple climate variability in the Pacific. In particular, ENSO strongly influences the longitudinal migration of skipjack tuna through the transport of warm water in the region (e.g., Lehodey et al. 1997), which therefore dictates the aggregation of macrozooplankton and micronekton that are their major food source. Based on catch data for skipjack tuna, catch rates were higher in the western Pacific during La Niña years while catch rates increased toward the east during El Niño years (see Bell et al., 2011 and references therein). For this reason, the availability of tuna in the Cook Islands is expected to fluctuate at an inter-annual time scale in response to ENSO. In addition, tuna availability can also be influenced by climate variability at the decadal scale. For example, Maunder & Watters (2001) have shown that the recruitment of yellow-fin tuna decreased during the negative phase of the PDO and increased during the positive phase in the eastern Pacific. Fishing activities in the Cook Islands Exclusive Economic Zone (EEZ) is divided into the Northern and Southern fishery grounds, with the majority of fishing activity taking place in the Northern grounds which is more productive and stable. The longline albacore fishery catch is generally unloaded or transshipped in Apia, Samoa or Pago Pago, American Samoa. In 2017 however, transshipment activities were conducted in Pukapuka under the supervision of a Cook Islands Fisheries Officers. The offshore catches in the Cook Islands zone are currently made by longline and purse seine vessels. The longline vessels are both locally and foreign based while purse seine vessels are all foreign based. The longline catch peaked at 15,500 mt in 2012 during exploratory fishing for Bigeye tuna. This has declined to 5,795 mt in 2016 as the fishery has reverted back to its regulated albacore catches. Over the same period, purse seining has become the dominant fishery in the Cook Islands, rapidly expanding from 476 mt in 2010 to a peak of 13,080 mt in 2015 (Figure 58). The purse seine catch in 2016 was 6,089 mt, and the preliminary 2017 catch estimate was 15,267 mt, which is a considerable increase.

Figure.58. Fishery Catch in the Cook Islands Exclusive Economic Zone. From SPC.

There are many concerns regarding purse seining due to its history of poor fishing practices. In 2015, the general public of the Cook Islands filed a petition to the Parliament of the Cook Islands with the intention of banning this type of fishing within the Marae Moana. The Prime Minster of the Cook Islands presented Government’s view of the issues on 23 April 2015 (Cook Islands News, 2015a). Two public protests were staged on Rarotonga to express their dissatisfaction of the decision to allow purse seining by the European Union for 8 years, with the first held on 24 April 2015 (Figure 59; Cook Islands News, 2015b). The Aronga Mana of Te-Au-O-Tonga with local NGO, Te Ipukarea Society (TIS)filed an application in court seeking a Declaratory Judgement. In an article to the Cook Islands News on 11 May 2019 (Cook Islands News, 2019b), TIS summarized the issue and how a resolution could be found from their perspective: “Conservation conflict can be defined as a situation that occurs when two or more parties with strongly held opinions clash over conservation objectives, and when one party is perceived to affirm its interest at the expense of another. Conservation conflicts occur primarily between people who have opposing values and views, or when there is a lack of trust between stakeholders. More commonly, conflicts can arise due to poor or inadequate consultations that result in key stakeholders being excluded from conservation planning or disadvantaged in negotiations by not being made fully aware of the available evidence to make informed decisions.”

After a decision and an appeal, the case is still pending resolution, and heading to the Privy Council in London in 2020 (Cook Islands News, 2019c).

Figure 59. First anti-purse seining protest in Cook Islands history, taking place on 24 April 2015 on Rarotonga.

The Cook Islands also supports a small local fishery of artisanal (small-scale) and game charter operators. In 2015, 142 mt of fish was caught by local fishers, increasing to 163 mt in 2016. Albacore and Yellowfin tuna together accounted for around 80 per cent of species caught by longline in 2016, with a decrease in Yellowfin in 2016 compared to 2015. However, some challenges were note with fish stock assessment especially in the outer islands because of the difficulties collecting catch data from fishers.

5.4.2 Benefits of fishing In 2016/17, fish accounted for $16.5 million of the total marine exports of $16.7 million for the Cook Islands. The main benefit to the Cook Islands Government from fishing activities is revenue from treaty arrangements, license fees and the sale of catch quotas. Revenue from fisheries activities in 2016/17 was $18.5 million. While it is uncertain how the benefit of game fishing and small-scale fishing in the Cook Islands are distributed in the population, a socioeconomic assessment on Rarotonga gave a conservative estimate of $2.4 million annually (Wichman, 2012). In fact, some argue that the benefit of small-scale fisheries far exceeds the benefits of large-scale commercial fisheries (Figure 60; Pauly and Zeller, 2016).

Figure 60. Comparing large-and small-scale fisheries during the period 2000 – 2010, which contrasts the performance of large-scale (industrial) and small- scale (artisanal and subsistence) fisheries on key criteria. Taken from Pauly and Zeller (2016).

5.4.3 Impacts of fishing Overfishing is one of the biggest concerns with any fishery, and there is a plethora of information in the literature discussing this issue (e.g., Jackson et al., 2001). For example, the latest stock assessment for Pacific bluefin tuna, released in 2016, found that nearly a century of overfishing has depleted the population to just 2.6 percent of its historic unfished size (PEW, 2016). Although the distribution of tuna is likely influenced by climate variability in the Cook Islands, there was an overall decline in all pelagic species throughout the Cook Islands based on interviews conducted by Climate Change Cook Islands in 2013 (Rongo and Dyer, 2014). In the northern group, elders shared stories of their catch 30 to 50 years ago; the size and quantity of their catch was bigger and more in comparison to what has been caught in recent years (Youtube link: https://www.youtube.com/watch?v=RejAyW2Ewmk). For example, a fisherman in Rakahanga indicated that yellowfin tuna with heads too big to fit into a 200-litre drum were often caught using the drop- stone method (P. Ropati, pers. comm.; see Youtube link), which is a story that would be seen as an exaggeration today. Yellowfin and skipjack tuna were abundant in the past, and time spent fishing was much shorter when compared with today. Furthermore, pelagic fishes were often caught close to land where at times the reef bottom was visible from a canoe (P. Toto, pers. comm.). However today, powered boats are used and fishing has become costly due to fuel usage, especially as fishers need to venture further away from land to fish.

5.4.3.1 Bycatch Fishing is about targeting certain profitable species as fishers would catch as many as possible within the specified management limits. However while fishing, some other species are caught which are not sold – this is known as ‘bycatch’. Bycatch is often thrown back to sea (in other cases, particularly with juvenile tuna that cannot be traded, it might end up in local markets, and this is known as ‘byproduct’). Over the years, steps have been taken to minimize bycatch. For example, member countries of WCPFC must implement the FAO Guidelines to vessels carrying out purse seine fishing and longline fishing for swordfish to avoid catching turtles (Pacific Island Species, 2019).

5.5 Recreation (not including fishing) Marine recreational activities in the Cook Islands are enjoyed by tourism and local residents alike. These activities include SCUBA diving, snorkelling, lagoon tours, surfing, wind surfing, kite surfing, banana boating (Figure 61) and paddling just to name the most popular. Some activities require powered motors, while others unpowered. Although most operate within the confinement of the lagoon for safety reasons, more and more activities are moving to the open ocean.

Figure 61. Banana boating is one of the newer activities that are operating in open ocean. Photo by Nana Tokari.

5.5.1 Current state and trends of recreation With tourism growth over the years, recreational activities in the Cook Islands have also seen an increase, especially on Rarotonga and Aitutaki. All of which have also injected a considerable amount of revenue into the country’s economy. Although most recreational activities are confined to the lagoon, there are more over-the-reef activities being offered to locals and tourists alike. In 2014, a total of 26 businesses were recorded that operates in the marine sector that includes fishing charters, diving, and other marine activities (Wilson et al, 2015).

5.6 Shipping

5.6.1 Current state and trends of shipping Hundreds of domestic and international ships transit the Cook Islands EEZ every year, bringing cargoes to and from the Cook Islands, including inter-island ships providing services for cargo and passengers to the Pa Enua. Shipping, as described in this report, includes vessels greater than 50 metres in overall length or carrying specialised product regardless of length (for example, oil tankers, liquefied gas carriers, cargo vessels). It also includes cruise ships and super yachts.

5.6.2 Benefits of shipping The benefit for shipping in the Cook Islands is extremely important considering the heavy reliance of the local population to imported goods. In fact, the frequency of cargo ships and the size of ship seem to have increased in the last 20 years.

5.6.3 Impacts of shipping In the last 20 years, several ships have run aground in the Cook Islands, one international ship, one cruiseline tender, and the rest are from local shipping company that service the outer islands (Figure 62). The damage of these groundings are mainly to coral reefs. However, none have been assessed. Other impacts such as the possible introduction of new species, oil spills within the harbour, and anchoring is not known. For example, the impacts of the fuel line leak in Avatiu Harbour in September-October 2019 – which took some time to repair – was not assessed (Radio New Zealand, 2019).

Figure 62. Top: Local shipping vessel ran aground near the entrance of the Avatiu harbour on Rarotonga. Photo taken from https://i1.trekearth.com/photos/19765/img_6240-rarop.jpg). Bottom: a tender ferrying passengers from the cruise ship MS Amsterdam became stuck on the reef at Arorangi, Rarotonga, in 2016 (Cook Islands News, 2016a).

5.7 Deep sea mining 5.7.1 Current state and trends of deep sea mining The Cook Islands Exclusive Economic Zone (EEZ) was reported to contain an abundance of manganese nodules by Russian and American vessels in the early 1970s (Kingan, 1998). Kingan (1998) chronologically summarizes the findings of fourteen exploratory research cruises within the Cook Islands EEZ undertaken by various countries under a United Nations-funded organization — the Committee for the Coordination of Offshore Prospecting in the South Pacific (CCOP/SOPAC) — from 1974 to 1990 (see references therein).

5.7.2 Benefits of deep sea mining The main minerals in the Cook Islands’ nodules (Figure 63) are Manganese, Cobalt, Nickel, Copper, Titanium as well as “Rare Earth Elements plus Yttrium” (REY); while harvesting this resource could potentially provide a significant revenue stream for the Cook Islands when global metal prices improve (McCormack, 2016). In 2013, Cook Islands Minister of Finance stated that “mining the minerals on the bottom of the South Pacific could increase gross domestic product a hundredfold” (The Guardian, 2013).

Figure 63 Top: Manganese nodules. Bottom: quick facts about seabed minerals in the Cook Islands. Photos taken from a presentation by Cook Islands Seabed Minerals Commissioner, Paul Lynch, at the Future Ocean Deep Sea Minerals Workshop in Kiel, Germany, in March 2013.

5.7.3 Impacts of deep sea mining It is questionable whether the benefits of deep sea mining would outweigh the potential environmental risks. It is argued that the Precautionary Principle should unequivocally be practiced in relation to deep sea mining considerations (McCormack, 2016). Environment NGOs on Rarotonga, Te Ipukarea Society and Kōrero o te ‘Ōrau, had the opportunity to review the amendments to the Seabed Mining Bill in 2019, which the Cook Islands Government moved to pass prior to opening tenders for five-year, deep sea mining exploration licenses. In the opinion of the environmental NGOs, there were not enough protections incorporated to address the potential environmental risks of these operations.

5.8 Assessment summary — Commercial and non-commercial use

5.8.1 Economic and social benefits of use Marine activities occurring within the Marae Moana continue to contribute to local communities and the national economy. The main benefit to the Cook Islands Government from fishing activities is revenue from treaty arrangements, license fees and the sale of catch quotas. Commercial marine tourism and artisanal fishing also continue to contribute to the economy, while shipping remains an important lifeline with the importation of goods into the country through the main port in Avatiu, Rarotonga. Traditional use of marine resources occurs with subsistence activities benefitting the household practitioners. The Cook Islands also continues to pursue interests in deep sea mining in hopes that revenue will substantially increase the country’s Gross Domestic Product, and diversify our economy because of the environmental and social impacts associated with tourism, which is currently the Cook Islands main industry.

5.8.2 Impacts of use on the Region’s values The impact of use on the Region’s values has limited information available, though events have occurred including ship groundings and fuel spills that would have a detrimental impact on marine life in the vicinity and adjacent areas.

5.8.3 Overall summary of commercial and non-commercial use There is limited information in relation to direct use of the Region, which are necessary to inform long-term risk assessment. It will be important to improve our understanding of community benefits derived from the Region and how factors around population and economic growth as well as changing societal attitudes affect the commercial and non- commercial use of the Marae Moana.

6. RISKS TO MARAE MOANA VALUES

6.1 Identifying and assessing the threats Coral reef monitoring throughout the Cook Islands has been ongoing in the Cook Islands for more than 20 years, albeit inconsistently (i.e., methodology, intervals, and also the government ministry involved) and primarily on the main island of Rarotonga over time (Table 7). One of the main objectives was to resurvey sites established as part of a long-term monitoring program designed to understand spatial and temporal changes of reef communities on the fore reefs. The first monitoring effort for Rarotonga was in 1994 (Miller et al., 1994) and subsequently in 1999 (Ponia et al., 1999), 2000 (Lyon, 2000) 2003 (Lyon 2003), 2006 (Rongo et al., 2006), 2009 (Rongo et al., 2009), 2011 (Rongo, 2011), 2014 (Rongo et al., 2014), and 2016 (Rongo et al., 2016). The Ministry of Marine Resources has also undertaken marine surveys in the Pa Enua, and visiting researchers sharing their survey results where relevant (e.g., Brucker, 2013; Newell et al, 2015 on their Aitutaki research; Figure 64).

Table 7. Coral reef monitoring on Rarotonga from 1994 – 2016.

Year Entity Reference 1994 Australian Institute of Marine Sciences Miller et al., 1994 1999 Cook Islands Ministry of Marine Resources Ponia et al., 1999 2000, 2003, 2006, 2009 Cook Islands National Environment Service Lyon 2000, 2003 Rongo et al., 2006, 2009 2011 Teina Rongo (Ph.D. dissertation) Rongo and van Woesik, 2013 2014 Climate Change Cook Islands (OPM) Rongo et al., 2015 2016 Climate Change Cook Islands (OPM) Rongo et al., 2017

Figure 64. Channel Islands researchers Newell et al. (2015) examining threats to coral reef communities in Aitutaki, Cook Islands in 2015.

6.1.1 Identifying the threats 6.1.1.1 Coral bleaching Coral bleaching is a stress response by a diversity of coral genera, often associated with a period of prolonged elevated ocean temperatures (Glynn, 1993; Goreau & Hayes, 1995; Brown, 1997; Hoegh-Guldberg, 1999). Consequently, this causes the symbiotic zooxanthellae (a photosynthetic dinoflagellate from the genus Symbiodinium) within the coral host tissue to be expelled, leaving the coral looking ‘bleached’. In the past, records of coral bleaching in the Cook Islands were mainly from the southern group (Table 8). In particular, the 1991/1992 and 1993/1994 bleaching event (associated with a mild El Niño event) were recorded in Aitutaki and Rarotonga respectively (Goreau & Hayes, 1995; Rongo et al., 2013). On the contrary, reports of coral bleaching in the northern group are limited to anecdotal accounts (see Table 1; Table 2 for La Niña and El Niño events since 1964). In the southern Cook Islands, coral bleaching has been reported during extreme low tides events associated with El Niño years where coral colonies on reef flats were exposed for several hours (Rongo et al., 2009; Rongo and van Woesik, 2013). In addition, coral communities in lagoon habitats during these extreme low tides can experience stagnant condition which can become warm. Also, El Niño events are associated with high irradiance due to higher probability of clearer skies in the southern group. As a result, such conditions have resulted in extensive bleaching in lagoons, reef

93 flat habitats, and also fore reef habitats at the mouth of passages that drain lagoon waters. For example, a mass bleaching event was noted on the reef flat and lagoon habitat of Aitutaki in 2014 (Figure 65; see Table below). While bleaching events tend to occur during El Niño events, they also occur during weak El Niño and Neutral ENSO events.

Figure 65. Top left & right; Coral bleaching observed in the Aitutaki lagoon and reef flat habitat during an extreme low tide event in 2014. Bottom left; bleaching due to exposure during extreme low tide on Rarotonga reef flat in Rarotonga in 2009. Bottom right; extensive fore reef bleaching in Rarotonga during a regional warming event in 2016. Photos taken by Teina Rongo.

Table 8. Bleaching event and associated ENSO phase throughout the Cook Islands. Bleaching include both those associated with regional warming and those local events associated with extreme low tides. YEAR ISLAND ENSO PHASE IMPACTS NOTED 1982/83 Rarotonga, Penrhyn, possibly Very strong El Niño Bleaching from extreme low tide; other southern and northern other southern and northern islands may have been affected as well, but not recorded. In group islands Penrhyn, micro-atolls (kava) were exposed for weeks and massive die-off of corals, clams and oysters were noted (Manata Akatapuria, pers. comm.). 1991/92 Aitutaki, Rarotonga Moderate El Niño Bleaching noted on the fore reef of Aitutaki and Rarotonga (Teina Rongo, pers. obs.) from extreme low tides. 1994/95 Aitutaki, Rarotonga, Manihiki Weak El Niño Maximum temperature was 30.1°C in Manihiki; extensive bleaching on Aitutaki and Rarotonga fore reef habitats (Goreau & Hayes, 1995). Also the beginning of the COTS outbreak 1997/98 Rarotonga, Penrhyn, Very strong El Niño Coral bleaching noted in the lagoon and reef flat habitats of Manikihi, Rakahanga Rarotonga and Penrhyn; bleaching on Rarotonga was due to extreme low tides. Although bleaching likely occurred on Manihiki and Rakahanga, this was not noted due to the overwhelming impact of cyclone Martin. COTS continue to degrade the fore reefs of Rarotonga

2001 Rarotonga Weak La Niña Large pulse recruitment of maito. In some place, maito recruits were washed up on the beaches dead. End of the COTs outbreak

2003 Rarotonga Moderate El Niño Coral bleaching in the lagoon from warm and stagnant conditions from extreme low tide. The “Titikaveka Irritant Syndrome” also occurred during this time (Rongo & van Woesik, 2013).

Coral bleaching noted in lagoon and reef flat habitats in Ngatangiia from extreme low tides (Rongo et al., 2006). 2006 Rarotonga Weak El Niño Large recruitment of Ctenocheatus striatus was noted on Rarotonga between January and February.

2009 Rarotonga Moderate El Niño Coral bleaching noted in the lagoon and reef flat habitats (Rongo et al., 2009).

2014 Aitutaki, Rarotonga, possibly Neutral ENSO Extensive bleaching noted in the lagoon and reef flat habitats from other southern group islands extreme low tides (Rongo et al., 2015).

2016 Rarotonga, Mitiaro, and Neutral ENSO Mass die-off of Echinothrix diadema. It is possible that other islands Ma’uke in southern group also had the problem. Mangaia was the only island confirmed to have avoided the disease

2016 Rarotonga and the whole Weak La Niña Extensive bleaching observed in the lagoons and fore reef of of the southern group. Rarotonga during the months of October 2016 to February 2017. Bleaching was also observed on Atiu, Mitiaro, and Ma’uke in the same months, where Tai Tu`a (extreme low tide during mid-day) was reported. It is likely that bleaching also occurred on the other southern islands.

Large pulse recruitment of Ctenocheatus striatus noted on 2018 Rarotonga Weak La Niña Rarotonga between January and February.

Information on bleaching events in the northern group are limited, thus observation from the 2015/16 bleaching event was critical (i.e., White, 2016; Rongo, 2016). Rongo (2016). It was noted that over 60% of corals were bleached

(both partial and whole colony bleaching). Differential bleaching was noted among habitats, with severity increasing from shallow reef flat habitats, followed by deeper lagoon habitats to fore reef habitats. Mortality of colonies was most predominant among Pocilloporids (i.e., Pocillopora meandrina and P. verrucosa) which is a branching species common on the fore reefs in the northern islands (Figure 67 with corals on the following page). Recovery from bleaching seem prevalent among the Montipora species, the second most common coral species on the fore reefs in the northern group. Coral colonies hosting multiple clades of the symbiotic microalgae Symbiodinium with different tolerance levels to thermal stress (Rowan, 2004; Berkelmans and van Oppen, 2006), may explain these differential bleaching among species. It has been suggested that branching corals are more susceptible to thermal stress due to their ability to scatter light efficiently within the colony (Enriques et al. 2017), this may explain the high mortality noted among branching Pocillopora species throughout the northern group. In support, Loya et al (2001) showed that increased bleaching events will also shift coral communities from the branching types (that are faster growing but low metabolism) to more massive types (slower growth rate with high metabolism). Also, Nakamura and van Woesik (2001) suggested that with forecast of increased frequency of bleaching episodes, size frequency distributions will be right skewed (smaller colonies), where reproduction will be reduced. During the very strong 2015/16 El Niño event, there was a latitudinal pattern noted with thermal stress across the northern group; severe bleaching was noted in the eastern most island Penrhyn, while Pukapuka, the western-most island was the least affected by bleaching (Figure 66). Whether this longitudinal pattern is historically the case or stochastic, is unknown, however the latitudinal pattern of bleaching is consistent with the contrasting effects of ENSO between the north and southern group (see section 2.2.3).

Figure 66. Four-week coral bleaching outlook map of the central Pacific region taken in January 2016 (http://cosppac.bom.gov.au/products- and-services/ocean-portal/). The Cook Islands EEZ outlined with the blue elliptical shape delineating northern group islands Penrhyn, Manihiki and Rakahanga in Alert Level 2 for coral bleaching. Pukapuka, Nassau, and Suwarrow (islands southwest of the delineation) were within Alert Level 1.

Figure 67. Top: Fore reef community in Penrhyn following the major bleaching event during the 2015/16 El Niño event. Partially bleached colonies of a Montipora species (lettuce type corals) recovering, and dark patches disbursed among the Montipora are

97 dead colonies of Pocillopora overgrown by turf algae. Bottom: Colonies of partially bleached Pocillopora species on the fore reef of Pukapuka recovering from the 2015/16 bleaching event. Photos taken by Teina Rongo.

6.1.1.2 Marine disease The health and continued existence of coral reef ecosystems are threatened by an increasing array of environmental and anthropogenic impacts (e.g., Harvell et al. 2002; Rosenberg and Ben-Haim 2002). These causes of decline, including global climate change, invasive species, shoreline development, habitat destruction, nutrient runoff, sedimentation and overfishing overwhelm the natural plasticity of these systems and have contributed to an estimated loss of 27% of the world’s reefs. If current pressure continues unabated, nearly 60% of the world’s reefs may be lost by 2030, due to reduced coral growth rates, bleaching, disease outbreaks and increased mortality. In particular, marine disease is now considered a major threat to the future sustainability of reefs (Green and Bruckner 2000; Aronson and Precht 2001). In the last few decades, diseases have increased for both marine fauna and flora. The Coralline Lethal Orange Disease (CLOD; Figure 68) was first identified in Aitutaki in1992 by Littler and Littler (1995). CLOD was reported to have affected an extensive area of Aitutaki’s reef slopes. Crustose coralline algae (CCA) plays an important role in cementing reefs together (e.g., Harrington et al., 2004) and a dominant substrate on the fore reef of Aitutaki (Rongo, 2008).

Dead tissue

Figure 68. Coralline Lethal Orange Disease (CLOD) found on the fore reef of Aitutaki; white area indicates dead tissue of the coralline algae Porolithon onkodes, with the orange band indicating the active area Live tissue of the disease. Photos taken by Mareike Sudek.

Although marine diseases are a natural part of ocean ecosystems, many have economic consequences for fisheries or aquaculture. Marine disease, especially on reefs, are receiving little attention in the Cook Islands; they only become noticed if they affect an important resource (e.g., urchin die-off in 2016; Rongo et al, 2016) or cause economic consequences (e.g., black pearl disease in 2000; Ponia 2000). Non-problematic diseases are only discovered by visiting scientists (e.g., Littler and Littler, 1995).

6.1.1.3 Ciguatera poisoning Ciguatera poisoning, a form of ichthyo-sarcotoxism, occurs when reef fishes inadvertently ingest dinoflagellates that produce ciguatoxins. Ciguatera poisoning is characterized by various symptoms, including gastrointestinal,

98 neurological, and cardiovascular. The symptoms can last from several weeks to several years (Lewis, 2006). Although rarely fatal, ciguatera poisoning is the most common seafood poisoning worldwide, affecting approximately 50,000– 500,000 people annually (Ragelis, 1984). With increased globalization of markets, ciguatera poisoning has become a concern well beyond the communities where the ciguatoxic fishes were caught (Van Dolah,2000; Wong et al., 2005; Dickey and Plakas, 2010). For the Cook Islands, reports of ciguatera dates back to the 1940s in Aitutaki and 1960s from the island of Penrhyn (Losacker, 1992). It was until the 1980s that ciguatera became a problem again in the southern group. First reports of this period was from Atiu in 1983, followed by Mitiaro. It was until the early 1990s when ciguatera became a problem for Aitutaki and Rarotonga (Rongo et al., 2009).

Causes of ciguatera poisoning outbreaks are still inconclusive, though several studies have suggested the contribution of various factors, including high nutrient loading (Carlson, 1984), natural and human destruction of reefs (Randall, 1958; Cooper, 1964; Banner, 1976; Tebano, 1992), loss of corals (Yasumoto et al., 1980; Kohler and Kohler, 1992; Bagnis et al., 1992a), elevated sea surface temperatures associated with global climate change (Tosteson et al., 1988; Hales et al., 1999; Chateau-Degat et al., 2005; Tester et al., 2010), and decadal climate oscillations (Rongo et al., 2009), are likely contributing to outbreaks of ciguatera.

Given that Rarotonga’s reefs has remained degraded for much of the 1990s and 2000s, it was suggested that such reef state accompanied by high frequency of disturbance events (e.g., cyclone, coral bleaching etc...) may have facilitated the establishment of the ciguatoxic dinoflagellates that causes fish poisoning – reef disturbance provide reef space for the opportunistic ciguatoxic dinoflagellates to colonize – this ultimately led to increased incidence of ciguatera poisoning in previous years (Rongo et al., 2009). Because ciguatera poisoning renders reef fish unusable in the last few decades, Rongo & van Woesik (2013) suggested that ciguatera may have also led to the increase of fish abundance especially herbivorous species (reported in the 2006 survey) which are particularly important during recovery period of reefs. On Rarotonga, Rongo et al. (2009) showed a significant correlation between ciguatera and reef disturbances (Figure 69), especially those associated with cyclones. Most importantly, they showed that the frequency of cyclones was key in determining the outbreaks (i.e., higher frequency leads to higher incidence).

Fig. 69. Cases of ciguatera poisoning from Rarotonga’s hospital data from 1994 – 2017 (Cook Islands Statistics Office). Blue star indicates minor anecdotal cases of ciguatera poisoning noted in 1972. Sun-shapes and horizontal arrows indicate periods of two major Acanthaster planci outbreaks: 1969–1976 (Devaney and Randall, 1973; Dahl, 1980), and 1995/96–2001 (Lyon, 2003; Rongo et al., 2006). Also shown are the years of Category 3 or less cyclones (open) (1970, 1972, 1976, 1978, 1989, 1991, 1992, 1993, 1997, 2001) and Categories 4 and 5 cyclones (black) (1987, 2003, 2004, 2005) impacted Rarotonga (Baldi et al., 2009). Black arrows indicate years of coral bleaching from extreme low tides, and red arrows indicate periods of extensive coral bleaching.

For the last 20 years, the world’s highest incidence of ciguatera poisoning has been reported in Rarotonga, in the southern Cook Islands. The Cook Islands Ministry of Health (CIMH) recorded a total of 2,327 cases of ciguatera poisoning between 1994 and 2006 (~194 cases yr-1). However, this number is an underestimate as only serious cases were reported; locals suffering from minor cases usually resort to traditional herbal Maori medicine. Rongo et al (2012) estimated that when ciguatera was severe (i.e., 2005 to 2006), up to 10% (~1000 individuals) of the resident population suffer from ciguatera annually.

In 2011, Rongo and van Woesik (2012) collected information from 179 households in Rarotonga and compared food consumption to a previous study by Solomona et al. (2009). This study showed that ciguatera poisoning halved the per-capita fresh fish consumption, from 149 g/person/day in 1989 to 75 g/person/day in 2006. Furthermore, it was suggested that ciguatera contributed largely to 71% of Rarotonga residents to excluded lagoon fish from their diet (Hajkowicz, 2006). Rongo and van Woesik (2013) estimated that the economic consequences of ciguatera poisoning amounted to approximately NZD $750,000 per year. Approximate costs associated with dietary shifts amounted to NZD $1 million per year. With the decline in cases of ciguatera poisoning in recent years, fresh fish has returned to the menu of residents, and the per-capita fresh fish consumption increased to 104 g/person/day in 2011. Yet over the last two decades, the impact of ciguatera poisoning on the local Rarotongan community may have had long-term health-related consequences, and may have changed the social, cultural, and traditional characteristics of a once subsistence fishing lifestyle.

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6.1.1.4 Watershed pollution Although coral reef ecosystems have been long regarded as oligotrophic (Odum & Odum, 1955; Johannes et al. 1972), it is generally accepted today that they are not limited to low nutrient environments (Hatcher, 1997). For example, Glynn (1977, 1981) noted that reefs exist in regions that experience seasonal upwelling. To date, it is poorly understood as to what role nutrients play on reef dynamic. Such knowledge gap has resulted in several heated discussions in the literature (e.g., Rinkevich, 2003 vs Loya, 2003; 2004). Perhaps the most controversial however was Lapointe’s (1997) proposed nutrient threshold hypothesis. This hypothesis, suggested that the nutrient concentrations at the sites studied were beyond the threshold levels of algal growth (i.e., 1 μM ammonia and nitrate, and 0.1 μM of phosphate; levels proposed by Bell, 1992); it was suggested this was largely sourcing from land. Watershed pollution has been suggested as the cause for the marine health hazards (Hajkowicz, 2006). However, information needed to make this connection can only be obtained through a consistent long-term monitoring program (Rogers et al., 1994). For the last 20 years the Cook Islands Ministry of Marine Resources have been conducting water quality testing around sites on Rarotonga and Aitutaki. Parameters tested include, dissolved oxygen, pH, salinity, nutrients, chlorophyll a, suspended solids, and bacterial contamination.

6.1.2 Assessing threats 6.1.2.1 Coral bleaching

The impacts noted from this 2015/2016 El Niño event (Figure 70) emphasize the need for more research in the northern islands to understand how various ecosystems respond to climate variability. In particular, we need to understand the synergy of impacts (if any) of an El Niño event and the La Niña event that follows. Certainly, the impacts noted in this 2015/2016 event alerts us to what to expect under a scenario of a warmer planet given the International Panel on Climate Change projections.

Figure 70. Left. bleached Pocillopora eyedouxi on the fore reef of Penrhyn. Right: bleached Montipora spp. on back reef habitat in Manihiki. Photos taken by Teina Rongo in 2016.

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Certainly, the impacts noted from this 2015/2016 El Niño event provides a snapshot of what to expect in our region with the projected warmer planet given the Intergovernmental Panel on Climate Change projections. They also indicate that no reef can escape the impact of thermal stress despite the different management efforts implemented, and whether they are inhabited or not. Hughes et al. (2017), continue to stress the importance of immediately curbing global carbon emission. Based on the Special Report on Global Warming of 1.5°C held in Incheon, Republic of Korea, highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. The report suggested that coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2°C. A promising study conducted on corals of Rarotonga (Palumbi, 2017), showed that some Rarotonga coral species (i.e., Acropora hyacinthus) host thermal stress tolerant symbiodiniums. They found that under experimental conditions, these corals were able to recover following severe thermal stress. In support, the recovery of corals in the southern group following the 2016/17 severe bleaching event was remarkable, with more than 85% of corals recovered (T.Rongo. pers.comm.).

6.1.2.2 Marine disease 6.1.2.2.1 Algal disease CLOD is a concern given the role that CCA plays in cementing together sand, dead corals, and debris to create a stable substrate for coral recruit and establish. Furthermore, Littler and Littler (1995) indicated that reefs affected by CLOD have a tendency to shift from being CCA and coral-dominated to being dominated by turf and fleshy algae. Rongo et al. (2013) also reported the presence of CLOD on Aitutaki in 2013, and suggested that more research is needed to understand the cause of CLOD on Aitutaki’s reefs and its distribution in the Cook Islands.

6.1.2.2.2.Pearl oyster disease In 1999 and 2000, black-lipped pearl oysters of Penrhyn and Manihiki experienced a severe disease outbreak respectively. With the impact of oyster disease along with the low international pearl prices, the export revenue for black pearls declined from NZD $18.4 million in 2000, to NZD $2.8 million in 2003, and to NZD $313,000 in 2016/17 (Cook Islands Statistical Bulletin, 2017). It was reported that the disease noted in Manihiki had never been previously seen by pearl farmers of Manihiki, suggest that the outbreak was unprecedented. Cultured oyster density in Manihiki lagoon was at an all-time high prior to the disease outbreak of 2000 (Ponia, 2000). Overcrowding, abnormally high temperatures and/or poor water quality was suggested as factors driving the outbreak. Subsequent investigations identified the pathogen causing the disease as strains of Vibrio bacteria; oysters were also checked (Figure 71). While the investigation around this disease focused around the pathogen, understanding climate conditions that drive disease outbreaks are just as important. In particular, climatic shifts associated with El Niño Southern Oscillation have been shown to drive disease outbreaks among humans (e.g., Pascual et al., 2012).

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Rongo (2016) suggested that degraded reefs from thermal stress associated with El Niño events likely harbour pathogens, while La Niña events that often follow these periods provide the ideal climatic conditions (i.e., clear skies, high irradiance stress, and calm conditions) for the pathogens to proliferate. In support, Rongo (2016) suggested that the disease outbreak observed in Manihiki in 2000, occurred during the calm conditions associated with the La Niña event from 1999 – 2001 following the severe El Niño event of 1997/98. A similar mass mortality of oysters occurred in the Gambier Islands of French Polynesia in 1985, and subsequently on a number of atolls in the Tuamotu group (SPC, 1985; Chagot et al., 1993); these events also occurred during a La Niña period (1983 – 1985) that followed the very strong El Niño event of 1982/1983.

Figure 71. Regrowth of nacre over conchiolin deposits immediately proximal to a prominent check in shell growth (arrows) in an oyster taken from Manihiki lagoon in 2003, three years after the disease outbreak in November 2000. Photo taken from Diggles et al. (2007).

In support, mass mortality of oysters noted in Manihiki in 2011 (CI News, 2012) was attributed to the shoaling of a dense layer of an anoxic water mass during a La Niña period (2010 – 2012) sitting near the bottom of the lagoon at around 40 – 50 m (Peter Nielsen, pers. comm.). In 2016, with a degraded reef, limited flushing in the lagoon (Callaghan et al., 2006), and climatic conditions normally associated with a La Niña event beginning to emerge in the northern group (i.e., clear skies, high irradiance stress, and calm conditions) following the El Niño event of 2015/16, based on past situations, conditions seemed ripe for pathogens and algal proliferation leading to disease outbreak and anoxic conditions; Rongo (2016) cautioned that a disease outbreak may occur, however there was no outbreak. Of note was the significant reduction in oyster density and active farmers in recent years (e.g., Ponia, 2000), and a New Zealand Aid clean-up of the Manihiki lagoon in 2017 (Cook Islands News, 2017a,b,c), which likely contributed to the disease-free outcome of 2017 and for much of 2018.

6.1.2.2.3 Urchin disease A mass die-off of vana (Echinothrix diadema; Figure 72), an important grazer on reefs, occurred between May and October 2016 on Rarotonga (Cook Islands News, 2016b), where a 99% loss was noted when compared with 2014 densities (Rongo et al., 2016). The die-off was first reported by dive operators on the fore reef, but by October, a significant number of E. diadema on the reef flat were killed off by the disease (Cook Islands News, 2016c); die-off was

103 also reported on the islands of Ma’uke and Mitiaro. Although, the cause of the disease is yet to be determined, a similar die-off was noted in the Caribbean in the 1980 (e.g., Lessios, 2016 and references therein), which to this day the cause is still unknown. Specimens of the diseased urchins analyzed by CAWTHRON Institute in New Zealand found toxins associated with a freshwater bacteria, Nostoc spp.

Figure 72 Left. Diseased Echinothrix diadema found on the reef flat of Avarua. Right: dead tests of E. diadema on the shores of Ma’uke in the southern Cook Islands. Photo by Teina Rongo.

6.1.2.3 Ciguatera poisoning What has become increasingly evident in recent years is the increased consumption of reef fishes by residents due to the decline of ciguatera poisoning. Consequently, many of the low risk species and those that are no longer high risk are heavily targeted by fishers (Figure 73). Considering the size of Rarotonga’s reefs, the size of human population, and improved fishing gears, the risk for low-risk species to be overfished is high. Unfortunately, many of the low risk species are important grazers (e.g., Acanthurids and Kyphosids) and can help strengthen the resilience of reefs. Adequate grazing on reefs is widely accepted as a necessary component for coral recovery (Edmunds & Carpenter 2001; Carpenter & Edmunds, 2006; Mumby, 2006).

Figure 73. Known low-risk reef fishes that are currently targeted heavily by fishers.

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6.1.2.4 Watershed pollution A watershed is an area of land of various sizes that catches rain and drains into streams or wetlands and eventually to sea. Watersheds provide water for drinking, irrigation, industry, and recreation; a healthy watershed is important for a healthy environment. Unfortunately, poor land-use practices such as landscaping for development, use of fertilizers and pesticides, and illegal dumping) within watersheds can not only contaminate our drinking water, but can also degrade downstream habitats and resources. It has been suggested that poorly managed watersheds of Rarotonga contributed to the problem of ciguatera fish poisoning that have plaque the island for the last 20 plus years. A socioeconomic study conducted in Rarotonga in 2005, estimated that if anthropogenic factors degrading reefs are prevented or reduced, the country would save NZD $7.4 million annually (Hajkowicz, 2006). Indeed, the majority of watershed research conducted in the Cook Islands are from Rarotonga, considering the problems observed in the lagoon environment over the last few decades.

6.1.3 Understanding community views In order to get the buy-in of a community to any management regime in the marine environment, it is important that the views of the community are integrated into the plan. Consultation at the different levels of the community (e.g., traditional leaders, church communities, tourist operators, fishers, and schools) are critical. However, obtaining these views may be challenging because consultations often are conducted through community meetings, which are convenient to those tasked to carried out the work; unfortunately, in such setting, only the views of those that are comfortable at public speaking are collected. Consultation with individuals, especially the users of the resource are also critical to get a wider view of the situation at hand.

6.3 Assessment summary – Risks to the Region’s values Risks to the Marae Moana needs to be assessed, but like many regions around the world, ecosystems within the Marae Moana continues to be at risk, and threats are likely to increase in the future. The most serious risks arise from climate change, nutrient loading, and, coastal development. The latter is likely a serious threat for the most developed islands (i.e., Rarotonga and Aitutaki). Potential threats to the Marae Moana come from fishing pressure associated with offshore fisheries and deep sea mining.

6.3.1 Risks to the ecosystem All ecosystems within the Marae Moana are connected, and therefore the impact on one will likely have a direct or indirect effect on another. However, for the most part, it is difficult to make these connections and especially the level of that impact when information is limited.

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6.3.2 Risks to heritage values The close connections between ecosystems and many of its heritage values mean that the projected risk of almost all threats is likely to be the same.

6.3.3 Overall summary of risks to the Region’s values The Marae Moana’s ecosystems and heritage values face a range of increasing risks into the future. Although we don’t fully understand the impact because of limited data, climate change impacts appear to be the most important threat to the Marae Moana ecosystems and heritage value. Other activities such as coastal development and fishing are likely contributing factors to risks and are likely to weaken the resilience of the relevant ecosystems. Concerns around activities such as deep sea mining pose potential threats to ecosystems and heritage values as well. Indeed, more information is needed for the entire Marae Moana before the next Outlook Report to have a better understanding of the changes, or to establish a baseline for some ecosystems.

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7. EXISTING PROTECTION AND MANAGEMENT

7.1 Background In the past, many marine fishes that have migratory and sedentary adults with large geographical ranges have been typically managed by controlling fishing efforts over large geographical scales (Palumbi, 2004). Today, a smaller scale management approach has been suggested. For example, Marine Protected Areas (MPA) has been widely adopted around the world (Almany et al, 2009). MPAs are not only beneficial for increasing density and biomass of exploitable resources but are becoming an effective tool for enhancing ecosystem resilience (Jackson et al, 2002; Bellwood et al, 2004). With small island nations in the Pacific, the ocean and its resources have sustained people for millennia. Yet, with the increasing impacts associated with climate change, climate variability, development, and overfishing, the need to conserve and sustainably manage resources is now more important than ever. Raùi (marine protected areas) has been a tool used by Pacific Islanders as well as other indigenous people for centuries to help populations of target species within a given area recover from the pressures of exploitation (e.g., Johannes, 1978; Veitayaki, 1997; Thornton & Scheer, 2012). In the Cook Islands, they are small-scale conservation zones established and managed by traditional leaders of each island. While raùi primarily focus on inshore marine ecosystems, these can also be established on coastal and inland sites. Typically, raùi put a temporary no-take on target species for a few months to a few years. Except for Pukapuka and Nassau in the northern group, the use of raùi has diminished over the last century in the Cook Islands. However within the last 30 years, the use of raùi has re-emerged, albeit in a more holistic approach where the entire ecosystem is considered.

7.1.1 Roles and responsibilities Challenges to establish and maintain raùi areas in the Cook Islands have been ongoing over the last few decades. Not only have there been funding challenges, but those tasked to carry out the process leading to the establishment of raùi have lacked the capacity and resources to do so effectively. In particular, the process relied heavily on the ‘western’ concepts of MPAs that are foreign to indigenous stakeholders, and as a result it minimized the inclusion of local and traditional knowledge in their management. Moreover, established raùi has mostly failed to gain the support of the community because the consultation process was too brief, lacked linkage between the traditional raùi and the western concepts of MPAs, mostly had inadequate socio-economic considerations of communities, and stakeholder roles have been ambiguous leading to lack of ownership and buy-in. On Rarotonga and Aitutaki for example, people complained that established rāùi primarily benefits a few – especially those in the tourism industry (e.g., some raùi are located in front of major hotels or used primarily by tour operators) – and limits the rights of the indigenous people to harvest marine resources for subsistence. However, the shift to benefit tourist operators and hotels have only occurred after 2000. In addition, some rāùi established after 2000 were too large that it became a

107 problem for local fishers. In some cases, areas known to be critical for conservation and ecosystem services that lack aesthetic value (e.g., nursery grounds in marshland environments adjacent to wetland areas) are not considered and are at risk of development. Nevertheless, the establishment of ra`ui has shown results. For example, a study of the Tikioki ra’ui found that there were more fish species inside the ra’ui than outside (Ponia et al., 1999, 1998; Raumea et al., 2000).

7.1.2 Focus of management Only recently have Cook Islanders come to appreciate the importance of using traditional and local knowledge to understand the impacts of climate change (Rongo and Dyer, 2014), and how the information can be used to guide the development of adaptation approaches without the aid of rigorous scientific studies. Similarly, traditional and local knowledge are important to guide the effective establishment and management of ra`ui, which includes the following: location and timing of target species recruitment, oceanographic patterns (e.g., areas where eddying occurs promoting larval retention), use of the lunar cycle to determine the availability of target species, location and timing of spawning aggregation events of target species, nursery grounds, oral traditions and anecdotal accounts of catch histories and fishing grounds, impacts of climatic shifts and natural disturbances on reef state and fisheries, the use of sustainable traditional fishing techniques, environmental indicators, and how terrestrial changes influence the state of the marine environment.

7.1.3 Management approaches and tools Traditional knowledge augmented with scientific knowledge can establish a more effective ra`ui without the use of elaborate scientific tools to facilitate the process; these scientific tools are often difficult for communities to use and understand, and therefore decreases the likelihood of buy-in. Traditional and local knowledge is also embedded in the language, cultural practices, and lifestyle of indigenous people (Berkes et al., 2000; Gómez-Baggethun et al., 2013).

7.2 Assessment of existing protection and management measures

Managing direct use

7.2.1 Research activities Over a century of on-going research, there is a plethora of information available on the Cook Islands covering a range of topics. Many of these research has shaped policy development in the Cook Islands across many sectors of government, the private sector, and the community. Most researchers are conducted by foreign academic institutions or organizations who have been issued a permit by the Office of the Prime Minister (OPM); Policy division, to carry out

108 their research in the Cook Islands. As a requirement, researchers would provide a 3 copies of their report to government (i.e., OPM) who will then distribute them accordingly. Often, a number of research would also take the next step to published their work in peer reviewed journals and many of these published researches are not easily accessible to Cook Islanders. Unfortunately, numerous researchers have also come into the Cook Islands without a permit; often their research are only discovered when published. Below is a summary of research in the Cook Islands from 1988 – 2013 (Table 9; Figure 74)

Table 9. Recorded research proposals for each island in the Cook Islands. A total of 368 proposals submitted and given a permit from 1988 to January 2013.

Study Island No. of Studies Percentage (%) Rarotonga 217 38.5 Aitutaki 63 11.2 Mangaia 52 9.2 Atiu 43 7.6 Mauke 23 4.1 Manihiki 21 3.7 Mitiaro 14 2.5 Penrhyn 12 2.1 Pukapuka 12 2.1 Palmerston 8 1.4 Suwarrow 6 1.1 Rakahanga 4 0.7 Manuae 3 0.5 Takutea 1 0.2 Nassau 1 0.2

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Figure 74. Recorded research proposals for each island in the Cook Islands. A total of 368 proposals submitted and given a permit

7.2.2 Traditional use of marine resources The Marae Moana Act 2017 passed by the Parliament of the Cook Islands in July 2017 created the largest multi-use Marine Protected Area in the world covering the country’s entire Exclusive Economic Zone (EEZ) of approximately two million square kilometres. The Act outlines the framework to managing the sanctuary, and Part 3 of the Act provides for the development of policies and spatial planning on individual islands within the Cook Islands. While the implementation of the Act is yet to start, the establishment of raùi on each island are at various stages: yet to commence, completed, or reassessment and evaluation needed. Traditional leaders with the support of a Technical Advisory Group for the Marae Moana ̶ consisting of appointed members from the relevant government agencies and non-government organizations ̶ are tasked to establish, monitor, and develop regulations for the raùi of each island. Currently there are 25 raùi established throughout the Cook Islands, covering an estimated area of 30.036 km2, which is less than 0.002% of the entire EEZ (see Figure 1); all raùi recorded are located in the southern group. Twelve islands in the Cook Islands are inhabited, and three are uninhabited (i.e., Suwarrow, Manuae, and Takūtea).

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Managing external factors 7.2.3 Climate change In the last few decade, climate change has become the most important issue globally, because of its cross cutting impacts affecting economies, people, ecosystems, weather patterns, and so on. While cutting greenhouse gas emissions sharply enough to reach the more ambitious climate mitigation goal requires a massive global shift in energy use, its impact will continue to shift the marine environment to undesirable states. Climate changes can influence factors that determine the distribution and survival of millions of marine species. These factors include, ocean currents, salinity and ocean pH, primary productivity, and ocean temperatures. One important factor to marine organisms is temperature, which is expected to increase under all model scenarios of climate change. Green and Fischer (2004) showed that elevated temperatures will increase larval development and swimming ability in fishes. Because connectivity among populations depends on the pelagic larval duration of marine organisms (Shanks et al., 2003), faster larval development would suggest that natal retention will be much higher and populations will become fragmented. Warmer temperatures will also result in higher metabolism and therefore higher demand for energy (Meekan et al. 2006). Because larval food resources are scarce in nature, these high energy demand will result in starvation (Edwards & Richardson, 2004). In addition, warmer temperatures will also increase the incidence of coral bleaching events globally (coral bleaching is covered in section 6.1.2.1). The least understood factor, which is also known as the “evil twin of climate change” is ocean acidification. The oceans are an incredible carbon sink — it absorbs about 25 % of the carbon dioxide produced by humans every year. Unfortunately, with more CO2 released into the atmosphere, the concentration of CO2 absorbed by the ocean also increase, making the ocean acidic. The result of an acidic ocean will upset the delicate pH balance that millions of marine organisms rely on. To date, most of our understanding of ocean acidification come from studies done in open ocean and less on the coastal environment. While there is very high confidence that the impact of climate change and ocean acidification will continue to increase, the concern here is the rate at which they are occurring; they rate is incredibly high that marine life may not be able to adapt and many will likely face extinction. For the most part, the impact of climate change in the Cook Islands is difficult to determine, because it is often confused with climate variability (e.g., ENSO). Because of the limited studies focused around climate change, a few have relied on traditional and local knowledge to understand the climate change. For example, the impact of sea level rise on atoll islands of the northern group are evident with the loss of coastlines, and the saltwater intrusion of water wells and agricultural lands (Rongo and Dyer, 2014). This is not to say that the impact of climate change is minimal in the Cook Islands. Indeed, with more research many more climate related impacts will surely be revealed.

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7.2.4 Coastal development Coastal areas are important habitats that connects the land to the sea; changes to the coast can cause changes to nearby land areas and marine ecosystems that can be detrimental or beneficial. In the Cook Islands, the last few decades have seen drastic changes on the coast. These include, loss of beaches and vegetation, loss of entire motus (islet), increased development for residential and tourist accommodations, and more reclaimed lands and seawalls; the last two are especially true for Rarotonga and Aitutaki. Many of the coastal developments are simply an attempt to climate proof. For example, more seawalls have been built on Rarotonga in the last 20 years, and in recent years, harbor on most islands have been upgraded. With increased awareness on climate change, we expect two scenarios of climate proofing to occur, 1) more climate proofing will take place on the coast, and 2) development will move away from the coast. Considering that land is limited in the Cook Islands, the former is most likely, despite climate models suggesting more severe cyclones for the region.

7.2.5 Land-based run-off Numerous land activities within the catchment especially on a few of the islands (i.e., Rarotonga, Aitutaki, Atiu, and Mangaia) can impact downstream ecosystems. Poor land use practices such pesticide and fertilizer use for agriculture purposes, animal husbandry, stormwater and sewage management, and landscaping works influence the quality and amount of freshwater that flows into downstream ecosystems. Components of runoff known to affect the marine ecosystems include nutrients, sediments, pesticides and other pollutants such as heavy metals and plastic debris. Some land uses result in diffuse contributions, while others have a more point-source signature. The contribution of pollutants from terrestrial point source discharges to the marine environment, such as sewage and stormwater runoff compared to non-point pollutant sources can be significant particularly during flood events for the latter. However, more research and monitoring is needed to understand the contribution of point source and non- point source pollutants for islands that have runoff problems.

Managing to protect the Region’s values 7.2.6 Biodiversity values The management and the protection of the regional values are mentioned in several of the Cook Islands’ legislations. The Marae Moana Act, 2017, is the primary legislation that is set out to protect and conserve the ecological, biodiversity, and heritage values of the Cook Islands marine environment. However, other legislations such as the Marine Resource Act 2005, also mention the conservation, management, development of the living resources in the fishery waters; the principals and measures of the Marine Resource Act must take into account that the biological diversity of the aquatic environment and habitat of particular significance for fisheries management should be protected.

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While the protection of biodiversity per se is not mentioned in any of the relevant Acts (e.g., Environment Act, 2003), biodiversity is protected through the protection of important habitats (e.g., wetland, coral reefs) from anthropogenic threats. For example, Part 6 of the Environment Act 2003, cover biodiversity protection.

7.3 Assessment summary — Existing protection and management Challenges exist to effectively monitor, manage, and protect the Marae Moana via the lack of capacity and funding to enable these activities. However, it is noted that the Marae Moana is still relatively ‘young’ in regards to its establishment in 2017, and the Cook Islands Government is currently looking into a sustainable financing mechanism scheme to support the various activities and responsibilities of the Marae Moana.

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8. FACTORS INFLUENCING MARAE MOANA VALUES

8.1 Background Factors external to the Marae Moana itself are playing an increasing role in determining its condition. Threats from climate change and climate variability have already been witnessed and ecosystem are vulnerable to its increasing effects especially coral reef habitats. Coastal development, primarily dredging, industry and population growth, is still significantly affecting coastal habitats that support nearshore habitats and the water quality. Despite improvements in local land management, the quality of catchment run-off entering lagoons will continues to cause deterioration in the water quality and reef health especially for Rarotonga and Aitutaki.

8.2 Climate change Increased global greenhouse gas concentrations drives climate change. Increased concentrations of greenhouse gases (particularly carbon dioxide) in the atmosphere will lead to more heat being trapped, increasing the Earth’s temperature, which can also drive sea level rise. Indeed, examples of climate change impacts in the marine environment have been reported extensively in the literature. Some of these impacts have contributed to the degradation of coral reef ecosystems worldwide. These included the loss of corals through bleaching events associated with elevated ocean temperatures, coral diseases, cyclones, and ocean acidification. With the latter, the ocean absorbs around 30% of carbon dioxide (CO2) released into the atmosphere. Consequently, increased atmospheric CO2, will lower the pH of the ocean, decreasing the availability of carbonate ions needed by calcifying organisms like corals, clams, and crustaceans (e.g., crabs and lobsters) to make their skeleton (Kleypas et al., 1999; Hoegh-Guldberg et al., 2007; Veron, 2011). Although there is limited information available on the impact of ocean acidification on coastal ecosystems, studies have shown that increased ocean CO2 ̶ especially at levels projected for the middle and the end of this century ̶ can reduce fertilization and settlement success of reef-building corals (Albright et al., 2010). In this report, elevated global temperature, sea level rise, and ocean acidification are key climate change factors that will likely influence the state of the Marae Moana.

8.2.1 Trends in climate change The climate projections for the Cook Islands are based on three IPCC emissions scenarios: low (B1), medium (A1B) and high (A2), for time periods around 2030, 2055 and 2090. Since individual models give different results, the projections are presented as a range of values. Projections for all emissions scenarios indicate that the annual average air temperature and sea surface temperature will increase in the future in the Cook Islands (Table 10). By 2030, under a high emissions scenario, this increase in temperature is projected to be in the range of 0.5–0.9°C in the Northern Group and 0.4–1.0ºC in the Southern Group; a similar trend is projected for ocean acidification . These changes will likely increase coral bleaching 114 events, diseases on coral reefs, and reduce recruitments. In terms of cyclones, projections tend to show a decrease in the frequency of tropical cyclones by the late 21st century and an increase in the proportion storm severity. Cyclone damage has been shown to bring significant damage to reefs and has also been linked to ciguatera fish poisoning (Rongo et al, 2012). Similarly, more intense flooding events are also projected that will likely increase terrigenous sediments on reefs especially for Rarotonga. All of these changes does not paint an optimistic view of Marae Moana in the future.

Table 10: Projected annual average air temperature changes for the Cook Islands for three emissions scenarios and three time periods. Values represent 90% of the range of the models and changes are relative to the average of the period 1980-1999 (Table taken from Pacific Climate Change Science Program, 2011) .

8.3 Coastal development Coastal development is likely a key factor influencing the health of the marine environment. This is especially true for Rarotonga and Aitutaki, the two most populated and developed islands for tourism. Activities on the coastline include construction of homes and tourist accommodation, seawall constructions, and dredging.

8.3.1 Trends in coastal development Since tourism became the main industry for the Cook Islands in the late 1970s, coastal development has increased especially in the last 30 years. Considering the number of tourist visiting the Cook Islands increasing, it is likely that coastal development will continue to increase as well.

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8.4 Assessment summary — Factors influencing Marae Moana values Climate Change and coastal development will continue to be factors influencing Marae Moana values. Consistent monitoring of these factors needs to be implemented to assist in determining what part these factors continue to play in Marae Moana values.

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9. LONG-TERM OUTLOOK

9.1 Background The outlook for the Marae Moana, is at a crossroad, and what the world and especially the Cook Islands Government decide in the next few years are likely to determine its long-term future. Indeed, the predictions of climate change paint a very bleak future for the most over the next few decades with thermal stress becoming more frequent, severe cyclone events, and increased disease prevalence on coral reefs, just to name two. Nevertheless, the persistence of these impacts will depend to a large degree on the direction desire that international community take to mitigate climate change. Despite limited information for the Cook Islands, anecdotal and local knowledge suggest that the state of marine ecosystem throughout the Cook Islands have declined, and will likely continue in this downward trajectory with continued increased of carbon dioxide concentration and sea surface temperatures. With these changes hard corals would likely become functionally extinct and coral reefs would be eroding rapidly. Although much considerations are implemented to improve the resilience of the Cook Islands’ marine ecosystem (e.g., establishment of a network of rā`ui by the traditional leaders), some national initiatives are worrying (e.g., ocean outfall options, deep sea mining) because of the risks. Therefore, the resilience will depend in large part on how effectively the risks of these initiative are managed. Variations in ecosystem response to the threats will differ depending on the proximity to concerned sites. Such differences are now observable and are likely to become more obvious over time if these risks are not managed accordingly. Generally, the areas at most significant risk are those closest to already developed areas that have already deteriorated more because of catchment runoff and coastal development. For some, threats related to climate change (e.g., coral bleaching in the northern group) these are predicted to worsen. Ultimately, if changes to the world’s climate become too severe, no management actions will be able to climate-proof these ecosystems in the Marae Moana.

9.2 Knowledge for management There is certainly a considerable gap in knowledge and understanding of the Marae Moana and there is a need to improve that through more research from institutes abroad, government agencies, NGOs, as well as research by commercial companies and consultants, Traditional leaders, and community members. Improving the understanding of the Marae Moana’s values and the threats that it faces will play a major role in securing their long-term future. Of course this will depend on a number of variables which will depend largely on the priorities of government.

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9.2.1 Improved understanding While research in the Cook Islands are sporadic, it has provided some baseline to work from for a few of the islands. In the order of good to moderate, Rarotonga, followed by Aitutaki, then Manihiki are the only islands that has some decent data available to serve as baseline. For example, we have some data on reef health on Rarotonga from the early 1990s up to 2016. In addition, the Ministry of Marine Resources have conducted water quality testing on Rarotonga and to a lesser extent Aitutaki and Manihiki for a period of the 2000s. Since the early 2000s reefs on Rarotonga has shown some improvement in the percentage of live corals following the devastation brought upon by the crown-thorn-starfish outbreak of the mid 1990s.

9.2.2 Remaining information gaps Indeed, marine monitoring efforts in the Cook Islands remain a gap, which is making it difficult to understand the drivers of change in the Marae Moana space. While monitoring has been focused largely on Rarotonga, and to a lesser extent Aitutaki and Manihiki, these have been inconsistent because they are project driven instead of a being a core responsibility for a ministry. Nevertheless, there is a need to develop a long term monitoring program for all the islands of the Cook Islands. More importantly, these needs to be guided or working alongside local and traditional knowledge systems that are available for each island.

9.3 Assessment summary – Long-term outlook 9.3.1 Outlook for the Marae Moana’s ecosystem Although more information is needed to confidently consider the outlook of the Marae Moana ecosystems, the overall outlook will likely vary among islands, and it is difficult to determine with the limited data available. Even with efforts to improve resilience, catastrophic damage to the some ecosystem may need considerable efforts to fix the problem (e.g., Aitutaki’s lagoon). Building the resilience of reef ecosystem within Marae Moana, from what lies ahead with climate change will vary depending on the island.

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Top photo: Teina Rongo. Fish photos: Graham McDonald

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