Most Impaired" Coral Reef Areas in the State of Hawai'i
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Final Report: EPA Grant CD97918401-0 P. L. Jokiel, K S. Rodgers and Eric K. Brown Page 1 Assessment, Mapping and Monitoring of Selected "Most Impaired" Coral Reef Areas in the State of Hawai'i. Paul L. Jokiel Ku'ulei Rodgers and Eric K. Brown Hawaii Coral Reef Assessment and Monitoring Program (CRAMP) Hawai‘i Institute of Marine Biology P.O.Box 1346 Kāne'ohe, HI 96744 Phone: 808 236 7440 e-mail: [email protected] Final Report: EPA Grant CD97918401-0 April 1, 2004. Final Report: EPA Grant CD97918401-0 P. L. Jokiel, K S. Rodgers and Eric K. Brown Page 2 Table of Contents 0.0 Overview of project in relation to main Hawaiian Islands ................................................3 0.1 Introduction...................................................................................................................3 0.2 Overview of coral reefs – Main Hawaiian Islands........................................................4 1.0 Ka¯ne‘ohe Bay .................................................................................................................12 1.1 South Ka¯ne‘ohe Bay Segment ...................................................................................62 1.2 Central Ka¯ne‘ohe Bay Segment..................................................................................86 1.3 North Ka¯ne‘ohe Bay Segment ....................................................................................94 2.0 South Moloka‘i ................................................................................................................96 2.1 Kamalō ......................................................................................................................126 2.2 Kamiloloa..................................................................................................................133 2.3 Kaunakakai................................................................................................................137 2.4 Kawela.......................................................................................................................145 2.5 Pālā‘au.......................................................................................................................150 3.0 South O‘ahu ..................................................................................................................161 3.1 Ala Wai Segment ......................................................................................................179 3.2 Kapalama-Nu‘uanu Segment ....................................................................................199 3.3 Ke‘ehi Segment.........................................................................................................208 4.0 West Maui .....................................................................................................................221 4.1 Kahekili Segment......................................................................................................239 4.2 Honokōwai Segment .................................................................................................242 4.3 Kahana Segment .......................................................................................................245 4.4 Honokahua Segment .................................................................................................248 4.5 Honolua Segment .....................................................................................................251 5.0 Establishment of New CRAMP Sites ............................................................................260 5.1 Site Locations............................................................................................................260 5.2 Benthic Results .........................................................................................................260 5.3 Reef Fish Results ......................................................................................................263 6.0 Data summaries..............................................................................................................266 6.1 Moku o Lo‘e CRAMP site ........................................................................................267 6.2 He‘eia CRAMP site...................................................................................................271 6.3.Ka‘alaea CRAMP site...............................................................................................275 6.4 Kamalō CRAMP site ................................................................................................279 6.5 Kamiloloa CRAMP site ............................................................................................282 6.6 Pālā‘au CRAMP site .................................................................................................285 6.7 Kahekili CRAMP site ...............................................................................................289 6.8 Honolua CRAMP site ...............................................................................................293 Final Report: EPA Grant CD97918401-0 P. L. Jokiel, K S. Rodgers and Eric K. Brown Page 3 0.1 Introduction. This project focused on four major coastal areas identified on the "Most Impaired" list for the State of Hawai'i in relation to monitoring and assessment sites throughout the state of Hawai'i. Each of the four broad target areas selected for this investigation include streams and water bodies identified by EPA and DOH as failing to meet water quality standards. This project represents the initial stage in a long-term commitment of the Coral Reef Assessment and Monitoring Program (CRAMP) to develop data syntheses that eventually will be web- accessible or available on CD ROM. The goal is to produce syntheses of information for each watershed in the main Hawaiian Islands. These syntheses will be updated as new information is produced. The four major study sites selected for this initial investigation were: 1. Kāne'ohe Bay, Oahu. The Kāne'ohe Bay watershed is urbanized (mostly residential) at lower elevations, especially in the southern portion. Low elevations to the north are in agricultural use. Land at higher elevations is generally in conservation use. 2. South Moloka’i - segment from Kamalō to Pala'au. The watershed feeding this reef is dominated by agricultural, conservation and light urban (residential) use. Overgrazing of vegetation by feral ungulates is a major issue leading to accelerated erosion and deposition on sediment and nutrient onto the reef. Major impact by sediment with extensive algal growth and evidence of eutrophication. Coastal construction (harbor and construction of a causeway at Kaunakakai) may be a major factor in blocking longshore current with consequent buildup of sediments and organics on the extensive reef flat. 3. South Oahu - segment from Diamond Head to Kewalo Basin with a focus on the reef area receiving discharge from the Ala Wai Canal. This segment has been heavily modified by coastal construction (dredging, fill, beach sand replenishment, shoreline hardening) and receives polluted runoff from Honolulu (industrial, commercial, hotel and dense residential). The area is heavily used for recreation and commercial vessel operation. 4. West Maui - Honokōwai north to Napili Bay and Hawea Point. This area has been impacted by severe sedimentation and nutrients from agricultural land. Honokōwai stream and Kahana stream drain into this area. Sewage injections wells are located in the region. Major algae blooms by Hypnea musciformis and other species occur periodically. Final Report: EPA Grant CD97918401-0 P. L. Jokiel, K S. Rodgers and Eric K. Brown Page 4 0.2 Overview of coral reefs - Main Hawaiian Islands Fig. 0-1. Map of the main Hawaiian Islands showing the 30 CRAMP monitoring sites (labeled by name) and the clusters for the 92 rapid assessment (RAT) sites. At each monitoring site there are two stations, one in shallow water (generally 3m) and one in deep water (generally 10m). General direction of waves influencing the Hawaiian Islands are also shown for reference (After Moberly and Chamberlain 1964). Two more sites were added (SE O'ahu, W. Maui) during 2004 to this array as part of this project. The Hawai'i Coral Reef Assessment and Monitoring Program (CRAMP) has surveyed a number of sites throughout the state (Fig. 1) and has produced a systematic and broadly comprehensive description of the spatial differences and the temporal changes in Hawaiian reef coral communities in the main Hawaiian Islands (Jokiel et al. 2004). These data were analyzed and two more sites (Ala Wai on SE Oahu and Mahinahina off W. Maui) were added to the array as part of this project. The two new sites were not included as they were not complete until 2004. This is a useful framework in which to evaluate the four "most impaired" coastal sectors discussed in this report. Information collected and analyzed to date (prior to the addition of the two additional sites) describes the major ecological factors controlling the status of reef coral communities in the main eight Hawaiian Islands (Jokiel et al. 2004). Methodology is described in Brown et al. (2004). Final Report: EPA Grant CD97918401-0 P. L. Jokiel, K S. Rodgers and Eric K. Brown Page 5 Briefly, the methodology used at the existing sites and the two new sites added as part of this project is as follows: CRAMP monitoring sites were selected to give a cross section of locations with differing accessibility, degree of perceived environmental degradation by expert observers,