Mode of access: World Wide Web. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 259-277). / Electronic reproduction. / Also available by subscription via World Wide Web / xvi, 277 leaves, bound ill. 29 cm

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1971. / Bibliography: leaves 159-166. / xi, 166 l illus., tables

Twenty-seven species of known or suspected coral skeletal borers were identified from shallow Hawaiian reefs. In comnarison to inventories of the borer communities collected from other tropical areas Hawaiian corals had an abundance of polychaetous annelids, fewer species of sipunculans,and acrothoracican barnacles, and far fewer boring sponges. Polychaetes were responsible for the majority of the bioerosion of dead coral in Kaneohe Bay, Oahu. Comparisons of living and dead sections of coral colonies indicated that the borer community was more diverse and abundant in areas of the skeletons lacking living tissue. Skeletal densities of three common coral species with branching growth form were found to influence the abundance of coral borers. The least dense skeletons had greater population densities of borers. It is suggested that these three species of corals can coexist in close proximity due, in part, to the development of varying abilities to withstand invasion by skeletal borers. In order to determine rates, si te preference and seasona.li.ty of settlement a series of settlement plates were cut from coral and placed in the field at ten sites in Kaneohe Bay, Oahu. Extrapolating from the surface area of the settlement plates, mean recruitment rates of coral borers were found to be 10,000 - 50,000 individuals m-2 month-1. The recruitment rates and species composition of epibiotic and borer faunas settling; on the dead coral plates differed dramatically between areas in Kaneohe Bay due to the effects of differences in physical and biological factors caused by sewage and slltation. The larvae of coral borers generally lacked clear seasonal settlement periods, suggesting that one or more mechanisms (e.g. continuous reproduction, long pelagic phase, etc.) functioned to assure the presence of larvae throughout the year. The ultimate cause for the development of such a strategy may be that the time and location of the production of suitable settlement sites on the reef surface is. unpredictable. Some of the larvae of both epibiotic and borer species exhibited settlement selectivity with respect to the position of the settlement surface. This finding indicates that the distribution of borers in coral skeletons might be due, in part, to active selection by the laryae for particular conditions. Development of the epibiotic and borer communities of dead coral was monitored using sequentially collected blocks cut from the coral Porites lobata. The abundance and species composition of these communities were found to differ between sites in Kaneohe Bay because of several biological and physical factors. In the south bay increased food supplies (in the form of plankton and plankton-derived detrital material). due to sewage enrichment, support extensive populations of filter and deposit-feeding invertebrates including coral borers. Sewage diversion did not appear to have had any dramatic effect on these communities by the end of the study period. In the north bay, where food availability is lower, fewer borers and epibiotic organisms were collected. The effects of fish grazing are considered to be another important factor determining the species composition and abundance of the coral borer community. Grazing fish were rare in south Kaneohe Bay during the study period, which may help to explain the abundance of sessile epifaunal species. In the north bay fish grazing is extensive and contributes to the growth of encrusting coralline algae on the test blocks and the benthos. Based on the results of the long term block study it was found that in Hawaii sessile filter-feeding invertebrates do not exclude coral borers from the substratum or inhibit their growth. In south Kaneohe Bay, where conditions caused increased abundances and growth rates of filter and depositfeeding invertebrates, bioerosion rates were accelerated. Encrusting coralline algae, which flourish on reefs exposed to fish grazing (eg. north Kaneohe Bay), inhibit settlement of borers and grow over burrow apertures, thus reducing the population of borers within the dead coral. Bioerosion rates of exposed, coralline algal covered, dead coral substrata are very low on pristine shallow Hawaiian reefs. / Bibliography: leaves 181-192.

Analysis of the pattern of zonation of reef corals off the Kona coast of Hawaii revealed the existence of four clearly defined zones. This pattern was confirmed at three sites where corals were counted using a series of 45 meter long transects running parallel to shore from depths of 3 to 40 meters. Clustering analysis dendrographs, spatial changes in illumination and rates of water movement, as well as growth and survival of coral transplants also confirmed the zonation pattern. Each of the four zones is characterized by a dominant coral species, substratum type, depth, and range of physical conditions. Each zone also appears to be in a different stage of community succession due to the frequency of large scale environmental disturbances from winter storm waves. The shallowest zone begins at the base of the shoreline cliff, ranges in depth from 2.5 to 8 meters, and has a bottom cover consisting mainly of irregularly shaped basaltic boulders; Pocillopora meandrina dominates coral cover in this zone. This species appears to be the first to colonize new substrata and persists in large numbers only in the near-shore boulder zone where mechanical stress from wave action is great enough to restrict the growth forms of more competitive species. Due to this high wave stress, the P. meandrina bolder zone appears to be in an early successional stage with low coral cover and dominance and relatively hiqh species diversity. Moving into deeper water the Porites lobata reef building zone ranges in depth from 6 to 14 meters and is characterized by a gently sloping solid basalt and limestone bottom. Porites lobata dominates coral cover by growing in massive lobed and encrusting colonies. While succession seems to be in an advanced stage, monopolization of available space does not appear to be complete enough to exclude a variety of less competitive species, resulting in relatively high species diversities. The third zone occurs on the reef slope and ranges in depth from 14 to 30 meters. Solid substrata is scarce and succession may be a late stage due to domination of bottom cover by thickets of Porites compressa. Most of the other species that persist in this zone avoid competitive interactions by growing above the level of P. compressa. Storm wave stress is most devastating to corals in this zone, and breakage of living colonies seems to increase diversity by reducing P. compressa dominance. Transport of living coral fragments appears to extend zonal boundaries and create new colonies. Extensive "rubble channels" occur in this zone, and these channels may get progressively larger due to churning of rubble fragments with each successive storm. The Porites lobata rubble zone occurs below the deep border of the P. compressa thickets and extends to approximately 50 meters, the depth at which coraIs cease to appear. Substrata consists mostly of fine sand and a variety of small encrusting corals are found growing on scattered rubble fragments. Specialized species with narrow physiological tolerances limited to this zone also increase species diversity. While maximum size of corals may be reduced in this zone due to low light intensity, lack of solid substrata probably determines the lower depth limit of coral occurance. Sand and rubble that is carried downslope during storms cause this zone to be physically unstable and succession appears to be constantly interrupted at early stages. This is in contrast to other deep reef areas, such as off Maui and the Red Sea, where substrata is solid to the depth limit of coral growth. These communities appear to be highly stable and diverse, and in late or climax stages. The depauperate nature of Hawaiian coral fauna is probably due to fairly rigorous environmental conditions in combination with difficulties in larval transport from coral evolutionary centers in the western Pacific. However, reef areas off Kona are relatively rich for Hawaii due to complete protection from tradewind generated seas, partial protection from long period north swells, and the steep nearshore slopes that extend below wavebase. / Typescript. Bibliography: leaves 173-181.