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Abstract: A series of scuba dives surveyed patches of black corals and their associated deep-reef fish community in the channel waters (50-73 m depth) of Maui, Hawai'i. Most of the corals were identified as Antipathes dichotoma and averaged 76 cm (±0.37) in height. Forty fish taxa were surveyed in the patches. Only Oxycirrhites typus was found exclusively within these coral trees. Sixty percent of the fish taxa surveyed were observed to frequent and pass through the coral branches. However, only four fish species were documented to reliably take shelter in the coral branches when evading an approaching diver. An archival video monitored movement patterns of fishes around a cluster of black coral trees for a 60-hr period. During daylight hours Dascyllus albisella, Centropyge potteri, Fordpiger flavissimus, Aulostomus chinensis, and Canthigaster jactator were observed to be the routine users of the coral patch, but only Oascyllus albisella and Centropyge potteri appeared to be resident to specific trees. At night Sargocentron sp. were observed feeding around the base of the coral trees, and Heniochus diphreutes dropped from their daytime position high in the water column to hide in the tree branches throughout the night. These observations indicate that black coral trees are used by many fishes as a general form of habitat, and if the coral trees are the largest relief feature at a site, their removal will likely impact the fish assemblage.
RECENT CONCERN ABOUT trawl fisheries damaging deepwater coral beds has spurred considerable interest in understanding the ecological importance of deepwater corals to the marine community (Auster et al. 1996, Freese et al. 1999). The fragile structure of the coral colonies, their patchy distribution, and their slow growth predispose this set of taxa to human impacts. The shallowest deepwater coral species, black corals (Antipathes spp.), are known to occur worldwide and are perhaps the most studied because of their relative accessibility and value as raw material for the jewelry trade (Grigg 1964, Gonzalez et al. 1997, Romero 1997). Despite this, the bulk of black coral resides at depths beyond conventional scuba diving, it is hidden from the public's general awareness and is difficult to study.
In Hawai'i black coral has been a focus of persistent low-level attention since 1958 when independent divers began harvesting...