CRAMP Study Sites: Island of Moloka‘i
Three standard CRAMP sites have been installed on Moloka‘i as part of an ongoing collaborative research effort with the United States Geological Survey (USGS) under Dr. Michael Field. Also see US Geological Survey, Geologic Studies OF Coral Reefs
Geographic Name: Moloka‘i Island
CRAMP site code: Mo
Geographic Location: (21° 08'N, 157° 00' W) Located between the islands of O‘ahu and Maui.
The Island of Moloka‘i is the fifth largest of the eight main Hawaiian Islands. The joining of two ancient volcanoes formed Moloka‘i: Mauna Loa to the west and Kamakou to the east. Erosion, deposition, slumping and secondary volcanic events modified the topography. The resulting shape of the island is elongated in the east-west direction, much in the shape of a peanut. The crest of the eastern volcano is named Kamakou, the highest peak on Moloka‘i (1515 m or 4970 ft). Steep mountain slopes that are deeply eroded and cut by numerous gorges characterize East Moloka‘i. In contrast, West Moloka‘i is a barren tableland that reaches only 400 m (1200 ft) in elevation. West Moloka‘i supports plantations, ranches and small farms.
Reef Structure, Habitat Classification:
Reefs along the north and west coasts of Moloka‘i are poorly developed due to frequent disturbance from the winter north and north-westerly swells. In addition, much of the north coast is undergoing erosion due to wave undercutting and slumping of volcanic material - a process that is continuing to this day. Reef accretion cannot occur under these conditions. The south coast, however, is protected from the north and northwest swells because of the elongate E-W structure of the island. The south coast is protected from severe south swell by the presence of Maui and Lāna‘i, which block waves from the south. An extremely well developed fringing reef exists along the entire south coast of Moloka‘i.
Adjacent Land Use:
two-thirds of the island is privately owned, 31% is State land and only 0.2% are federal lands (Atlas of Hawai‘i, 1973). Private lands are mainly in the hands of large landowners (45% of the island), the largest being Moloka‘i Ranch, Ltd. Small private landowners hold only 6% of the island land area.
Human Use Patterns:
Sustenance fishing is the major activity on Moloka‘i reefs (Baker, 1987). A variety of techniques ranging from trolling, bottom fishing, netting and spearing are utilized. Gathering of limu (seaweed), shellfish and crustaceans is widely practiced. A limited amount of commercial catch is sold locally with some being air flown to Honolulu markets. Local inhabitants use the reefs for recreational swimming and surfing. Only one commercial dive tour company is in operation. Fishing charters operate from Kaunakakai wharf.
Economic Value and Social Benefits:
Sustenance fishing is an extremely important economic activity to the local population (Baker, 1987). Small commercial fishing operations and fishing/dive charters exist on Moloka‘i, but are not a major economic feature.
Status (Degree of Legal Protection):
No Marine Life Conservation Districts exist on Moloka‘i. A portion of Kaunakakai harbor is restricted to certain types of fishing activity. Authority for managing the marine resources within three miles (4.8 km) of Moloka‘i lies with the Division of Aquatic Resources, Department of Land and Natural Resources. All laws pertaining to the management of state marine resources apply (see pamphlet "Hawai‘i Fishing regulations, September 1999", 51 pp. available from Division of Aquatic Resources, Department of Land and Natural Resources, Kalanimoku Building, 1151 Punchbowl St., Rm. 330, Honolulu, Hawai‘i).
Impact of land-derived sedimentation on the coral reefs of south Moloka‘i has been and continues to be the major environmental concern on Moloka‘i. A related issue is the role of the Kaunakakai causeway in blocking the shoreline transport of sediment, nutrients and other land-derived materials with consequent degradation of the reefs. The Florida Red Mangrove was introduced in an attempt to stabilize mud shorelines on Moloka‘i. These plants have spread throughout the State of Hawai‘i and are often considered to be an invasive alien species. Some local inhabitants are concerned about overfishing by boats that come to Moloka‘i from other islands and harvest using extremely long stretches of gill nets.
Noteworthy Biota or Ecological Conditions:
At least two coral species that are rare throughout the Hawaiian Archipelago can be found on Moloka‘i. Gardenoseris planulata has previously been reported only from Maui (Ahihi Kinau) and Kaho‘olawe. This species is common in shallow water (3 m) at Pālā‘au. Another rare coral species, Montipora studeri, also occurs here. A third rare species, Porites pukoensis, was described from specimens taken at Pukoo and takes its species name from this location. Deep "reef holes" on the southern reef are unique features worthy of further study. A reported infestation by the coral-eating "Crown of Thorns" starfish Acanthaster planci in the late 1960's (Branham et al., 1971) is the only occurrence of this type ever reported from Hawai‘i. The introduction of mangroves along the south shore and subsequent formation of thick mangrove forests to the west of Kaunakakai is of interest to ecologists. The impact of the mangroves on shoreline processes and the ecology of the inshore area is undergoing further study at present.
Impact of land-derived sedimentation on the coral reefs of south Moloka‘i has been and continues to be the major environmental concern on Moloka‘i. A related issue is the role of the Kaunakakai causeway in blocking the shoreline transport of sediment, nutrients and other land-derived materials with consequent degradation of the reefs. The Florida Red Mangrove was introduced in an attempt to stabilize mud shorelines on Moloka‘i. These plants have spread throughout the State of Hawai‘i and are often considered to be an invasive alien plant. some locals are concerned about overfishing by boats that come to Moloka‘i from other islands and harvest using extremely long gill nets.
Historical and Cultural Importance:
Moloka‘i has been called "the last Hawaiian place" because the life style has not been impacted by urbanization and tourist development. Many residents are working to protect Moloka‘i from changes that would alter their way of life. The island is largely rural. Numerous Hawaiian fishponds exist along the south shore. These are believed to have been built between 1500 - 1800 AD.
Scientific Importance and Research Potential:
Moloka‘i is clearly one of the best locations in the State of Hawai‘i to study the effects of land derived sedimentation on coral reefs. Further, the wide fringing reef along the south coast is the longest and best-developed fringing reef in the main Hawaiian Islands. There are many questions about why and how such a massive reef structure has developed. Thus it has become a focal point for joint UH-USGS studies of reef dynamics in Hawai‘i.
Relevance of Location to CRAMP:
Moloka‘i is undoubtedly the best location in Hawai‘i to document the impact sedimentation on coral reefs. Kaho‘olawe has suffered similar impacts of sedimentation, but is relatively inaccessible for study. In addition, Moloka‘i has the most extensive and best-developed fringing reef in the State of Hawai‘i.
Atlas of Hawai‘i (1973) R. W. Armstrong (ed). University of Hawaii Press, Honolulu, Hawaii. 222 pp.
Baker M.E. (1987) Backyard fishing on the south coast of Moloka'i. M.S. Thesis University of Hawai'i. 128 pp.
Branham J.M., Reed S.A., Bailey J.A. and J. Caperon (1971) Coral-eating sea stars Acanthaster planci in Hawaii. Science, 172: 1155-1157
Last Update: 04/21/2008
By: Lea Hollingsworth
Hawai‘i Coral Reef Assessment & Monitoring Program
Hawai‘i Institute of Marine Biology
P.O. Box 1346
Kāne‘ohe, HI 96744