View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ScholarSpace at University of Hawai'i at Manoa Black Coral: History ofa Sustainable Fishery in Hawai'i1 Richard W Grigg 2 Abstract: The black coral fishery in Hawai'i has been sustainable for the past 40 yr. The fishery began in 1958, shortly after its discovery off Lahaina, Maui, by Jack Ackerman and Larry Windley, who later formed the company Maui Divers of Hawaii. Since that time, the black coral jewelry industry has gradually expanded and is valued in Hawai'i today at about $15 million at the retail level. In the 1970s, studies ofthe population dynamics of the major species established growth, recruitment, and mortality rates and led to the development of man­ agement guidelines including recommendations for a minimum size and maxi­ mum sustained yield. Results of a recent survey in 1998, reported in this paper, show that rates of recruitment and growth are near steady state and appear to account for the long-term stability of the fishery. However, recent technological advances and potential increases in demand could lead to increased rates of harvest. Should this happen, more stringent regulations may be required to avoid overexploitation of the resource. THIS PAPER OUTLINES the history of the 4.8 km west of Lahaina in the middle of the black coral fishery in Hawai'i and reports the 'Au'au Channel between Maui and Lana'i at results of a recent survey of the Maui black depths of 30-90 m (Figure 1). coral bed conducted in 1998. The objectives Subsequent exploration by these pioneers of the survey were to obtain measures of showed that the 'Au'au Channel bed extended abundance, recruitment, and size frequency for many linear kilometers along steep topo­ of the two main species, Antipathes dichotoma graphic drop-offs in the channel between Pallas and A. lVandis Verrill, and to evaluate Maui and Lana'i. Recognizing the value and the sustainability of the resource. In brief, the extent of their find, Ackerman and Windley goal was to reassess maximum sustainable started a small business in Lahaina, Maui, in yield ofblack coral in the 'Au'au Channel bed 1958, for the production and sale of black off Maui. coral jewelry. They named their small com­ pany Maui Divers of Hawaii (Stewart 1962). The harvest of black coral in Hawai'i has History ofthe Black Coral Fishery in Hawai'i traditionally been carried out by scuba divers. The black coral fishery in the Hawaiian Is­ In the early years of the fishery, divers har­ lands began in 1958 when a large bed ofblack vested black coral by cutting or breaking the coral consisting primarily ofA. dichotoma and coral from the bottom with an ax and sledge. A. lVandis was discovered off Lahaina, Maui, They then tied the coral to their boat anchor by Jack Ackerman and Larry Windley (Grigg lines (Figure 2). At the end of the dive, the 1965). The site oftheir original discovery was anchor and coral "trees" were buoyed to the surface by inflating lift bags on the bottom. Lift bags are still used today to float the coral 1 This research was supported by a grant (1448­ to the surface, but the divers no longer an­ 9821O-98-M517) from the U.S. Fish and Wildlife Service Office of Scientific Authority. Manuscript accepted 6 chor over the beds. Instead, they use a "free November 2000. boat" method in which the boat follows lift 2 Department of Oceanography, University of Ha­ bags as they reach the surface. The divers as­ wai'i at Manoa, Honolulu, Hawai'i 96822. cend with their last lift bag (Figure 3) and decompress while the boat drifts above them on the surface. On an average dive, two to Pacific Science (2001), vol. 55, no. 3:291-299 © 2001 by University of Hawai'i Press four trees (colonies) of black coral are har­ All rights reserved vested; each colony weighs between 2 and 291 292 PACIFIC SCIENCE· July 2001 22° N' 2~0 r-----,---r---,...-----,-----,---.----, 22° 21° 20° o loomi _ Abundant (0.1-1.0 colonies/m2) 1-1---r---"'-,...----" 19° 0 100km .. Moderate (0.01-0.1 colonies/m2) 2) 161°W R Rare «0.01 colonies/m FIGURE 1. Map showing the location of black coral beds in Hawai'i. 5 kg (5-10 pounds). The total weight ofcoral abundance, growth, natural mortality, and harvested per dive, per diver, averages ,,-,10 kg recruitment. (22 pounds) and is valued in today's market at During the next 5 yr, two large black coral $25/pound. The depth range of harvested beds were identified in the state and assessed: black coral is 40-75 m (130-250 feet). the Maui bed and a smaller bed off Kaua'i. Between 1960 and 1970, the black coral Both areas were mapped and estimates of jewelry industry in Hawai'i grew steadily. By maximum sustained yield (MSY) were calcu­ 1969, about one dozen small companies had lated. Mapping was based on the catch rec­ joined Maui Divers and together they pro­ ords of commercial divers, as well as about duced about $2 million in gross sales of black 100 dives by the University of Hawai'i re­ coral jewelry. Although the economic poten­ search team (R. Grigg, S. Dollar, M. Palm­ tial of the industry had been firmly estab­ gren, J. Angel, and G. Galiher). The areal lished by that time, little was known about the coverage of the Maui and Kaua'i beds was 2 2 ecology of the resource and whether or not determined to be 1.7 km and 0.4 km , re­ natural growth rates of the coral were suffi­ spectively (Figure 1) (Grigg 1976). Corre­ cient to sustain commercial harvest rates. In sponding estimates of MSY for the two beds response to this need for information, in were found to be 6174 kg/yr and 1480 kg/yr. 1970, a major long-term research program MSY values were calculated using a Beverton began at the University of Hawai'i on the and Holt yield production model (Beverton ecology of precious corals. The study in­ and Holt 1957, Grigg 1976). cluded surveys to establish the distribution Actual values of MSY recommended to and abundance of all black coral beds in the state and federal agencies (5000 kg/yr and state and to determine size limits and opti­ 1250 kg/yr, respectively) were about 15% less mum harvest yields based on measures of than the yield per recruit based on the model Black Coral . Grigg 293 FIGURE 2. In the 1960s, black coral was harvested with axes and sledges. Colonies were tied to the anchor line and then buoyed to the surface. estimates (900 g per recruit versus 1050 g per search in the 1970s, the State of Hawai'i recruit [see Grigg 1976]). This downward re­ enacted a draft regulation for a minimum size vision was recommended to permit the har­ limit of 48 inches (1.2 m) (Draft Regulation vest of slightly smaller colonies consistent 48). No weight quotas were adopted because with traditional fishing practices. Basically, it the size limit was considered a de facto proxy allowed the divers to continue their past for MSY and was more easily enforced. Dur­ practice of harvesting colonies down to a ing the 1980s and 1990s, black coral divers height limit of 48 inches (1.2 m). Industry and industry buyers (jewelry producers) vol­ demand for colonies less than 1.2 m is low untarily complied with Draft Regulation 48. because most branches of colonies less than During the 1980s, several major changes that height are too small in diameter to pro­ took place that affected both the black coral duce jewelry. Hence the 1.2-m size limit can fishery and industry in Hawai'i. The first be considered an "optimum yield" (Gulland change was a slow but steady improvement in 1977). The size limit corresponding to opti­ the efficiency in cutting and polishing black mum yields of 5000 and 1250 kg/yr deter­ coral jewelry products. Cliff Slater (pers. mined by the model is 1.2 m for both A. comm.), CEO of Maui Divers, the largest dichotoma and A. grandis. The same size limit precious coral jewelry company in the state, can be applied to both species because of estimated that technological improvement in similarity in their growth rates: 6.42 cm/yr coral processing during the 1980s led to a and 6.12 cm/yr, respectively (Grigg 1976). several hundred percent decrease in the In the years following this period of re- amount of coral consumed to produce the 294 PACIFIC SCIENCE· July 2001 TABLE 1 Annual Records ofWorked Black Coral Pieces Imported into the United States Year No. of Pieces 1982 408,773 1983 411,723 1984 260,879 1985 511,268 1986 616,978 1987 608,288 1988 425,237 1989 522,703 1990 279,457 1991 183,463 1992 354,656 1993 209,724 1994 606,261 1995 155,194 1996 330,496 1997 293,473 1998 274,188 Source: Ed Green, World Conservation Monitoring Centre, 219 Huntington Road, Cambridge, U.K raw black coral by the industry in Hawai'i during the same period was less than 2000 kg/yr (Oishi 1990) (Table 2). Landings of black coral reported harvested FIGURE 3. Today, float bags are used by the black coral in Hawaiian waters over the past 16 yr are divers to float coral colonies (trees) to the surface. summarized in Table 2 and presented graph­ ically in Figure 4.