CRAMP Long Term Monitoring Study Sites: Honolua, Maui

Honolua Bay is located on the northwestern coast of Maui, about 10 miles north of Lahaina. Coordinates for MaHonN and MaHonS sites are, respectively,

Chart showing Honolua coastline. Red arrows show location of transect sites. (Click for larger view.)

Honolua Bay is a semi-enclosed bay with an area of approximately 46,000m2 (500,000ft2). Along the north and south slopes the shoreline area consists of a series of basalt cliffs and ledges with larger boulders fronting the shore. This gives way to reef flats on both the north and south faces of the bay. A reef crest occurs on the seaward edge of the reef flat with a steep slope from the crest down to the central channel at a depth of 8-13m. The central portion of Honolua bay consists of a sand channel interspersed with beds of Halimeda sp. This sand is coarse, with the carbonate fraction increasing from the shoreline to the outer edge of the bay. A sand beach interspersed with small rocky boulders exists at the head of the bay.. The intermittent Honolua Stream transports varying amounts of fresh water and silt into Honolua Bay during rains. As a result, inshore waters of the bay near the boat ramp area are can be very murky. The bottom here consists of small boulders and silt. Visibility improves towards the mouth of the bay. The middle of the bay is occupied by a large sand channel, sloping gradually to a depth of about 60 feet at the bay‘s mouth. On either side of the bay are dense coral formations in waters ranging from 10 to 40 feet deep. Coral is more abundant and diverse along the northeastern shoreline. Small caves and archways are found near the point on the bay‘s south margin.

Two coral reefs border the northern and southern flanks of the bay. The south reef has a basalt substrate with coverage around 25-30%. The north reef has coral coverage near 20-25% on the reef flat. Coral coverage increases with depth to approximately 70-80% until finally giving way to the central sand flat. The central sand flat occurs at a depth of 40‘ and is covered with patches of the alga Halimeda sp.

Photoquadrat of the North Honolua Bay 3m transect.

Photoquadrat of the South Honolua Bay 3m transect.

Honolua Bay North, Maui 3m

Total coral cover: 15.3%

Species Richness: 12

Dominant Species: Montipora capitata

Honolua Bay South, Maui 3m

Total coral cover: 20.9%

Species Richness: 11

Dominant Species: Montipora flabellata

Photoquadrats of the Honolua Bay North and South sites from the 3m transects.

The bay is calm during most of the year but is severely impacted by North Pacific Swell during the winter months.

The land surrounding Honolua Bay is owned by Maui Pineapple Co. and is in conservation and agricultural use.

This is one of the most popular water recreation sites on Maui. The only overland access into Honolua Bay MLCD is an unimproved, gated, one lane private dirt road intersecting the Lower Honoapiilani Highway. Use of this road requires a permit from the landowner, Maui Pineapple Company. The only existing improvement is a weathered boat ramp. There are no public restrooms or telephones nor access to electricity or freshwater. Honolua Bay MLCD is undeveloped.

Brown conducted a human use study of Honolua Bay in the late 1990's. Peak human use was between 11am to 2pm with summer months recording the highest visitor traffic. The maximum visitor count of 222 people was observed on August 23rd 1998. The majority of visitors engaged in snorkeling activities over both reef areas from the beach and boats. Less than 5% of the total people were SCUBA diving or surfing and no fishing was ever observed within the MLCD boundary. Human use at Honolua Bay is high compared with other areas on Maui with the possible exception of Kahekili Park. Human use patterns may also negatively impact the reef area, which may help explain observed decreases in coral coverage observed over both reefs within the bay.

Commercial fishermen use the boat ramp at Honolua to launch their vessels and use the shoreline as a base camp for their offshore activities. Commercial tour boat operators bring up to 250 people per day to this site. Primary uses of the bay include recreational diving, snorkeling and boating activities that may or may not involve anchor placement. Over the past few years Honolua Bay has become extremely popular with both tourists and visitors. Up to 600-700 people visit the site daily during peak season (Brown, 1999a).

No marine life can be taken in Honolua, so this MLCD plays a role in production of larvae and fish that enhance other coastal areas that are being subjected to fishing pressure. Honolua bay is an important tourist destination and thereby enhances the economy of the State of Hawai‘i.

Honolua Bay is part of the Honolua-Mokulē‘ia Bay Marine Life Conservation District (MLCD) established in 1978. The MLCD extends from the highwater mark seaward to a line from‘Alaelae Point to Kalaepiha Point, then to the point at the northwestern corner of Honolua Bay. Fishing for, taking or injuring any type of marine life is prohibited, as is the possession in the water of any type of fishing gear. However, possession of fishing gear, or fish taken outside of the District, is permitted aboard boats. Bagging and removing akule netted outside of the District is allowed with a special permit. Authority for managing the marine resources within three miles (4.8 km) of the high tide mark 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).

The major concern at Honolua has been the large number of visitors that utilize the area in spite of very restricted access. Continued growth of the number of visitors could lead to increasing environmental concerns such as those occurring at Hanauma Bay MLCD and Molokini MLCD. Changes in adjacent land use on the watershed draining into Honolua in the future would raise concerns related to increased sedimentation and nutrification. Anchor damage and fish feeding are also concerns.

Honolua Bay Marine Life Conservation District (MLCD) located in the northwestern section of Maui has one of the most diverse, unique and abundant reef formations on the island (Environmental Consultants, 1974; AECOS, 1981). Several resting areas for the threatened green sea turtle (Chelonia mydas) have been identified on both the north and south reefs. The majority (8-9) of turtles observed at Honolua appear to reside on the northwestern section of the reef crest just inside of the MLCD boundary.

Since 1989 the Pacific Whale Foundation (PWF) has been involved in the monitoring of fish and coral within Honolua Bay using benign techniques to access changes in community dynamics. The PWF monitoring protocol was expanded in 1996 to include physical factors. In 1997 this investigation began observations on human use patterns at Honolua and several sites on west Maui in order to assess possible direct anthropogenic factors such as reef walking impact on corals. This site was absorbed into the CRAMP network in 1999 with a continuing partnership with the Pacific Whale Foundation. Studies are continuing under this arrangement.

Studies should be undertaken before any plans to improve access and local facilities are implemented. Improving access will have an impact on the bay. Any change in watershed use could cause damage to the Honolua bay reefs. Commercial diving tour operations must be monitored and kept to a reasonable level of activity. Mooring pins must be maintained to prevent anchor damage.

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CRAMP Study Sites: Honolua, Island of Maui