Pacific Science Volume 30, Number 2, 1976
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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.
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ItemThe Correlation of Soil Algae, Airborne Algae, and Fern Spores with Meteorological Conditions on the Island of Hawaii(University of Hawaii Press, 1976-04)Correlations of the generic diversity of soil and airborne algae with altitude on the island of Hawaii are noted. Distribution of the soil algae was determine d by culturing an aqueous soil extract from designated altitudes on agarized inorganic growth media. Distribution of airborne algae and fern spores was determined by investigations of viable particulate impactions on the surface of agarized inorganic growth media identical to that used in culturing the soil samples. Little correlation occurs between the generic diversity of the airborne and soil algae at corresponding altitudes, which suggests a cosmopolitan mixing of airborne propagules that have been released from different altitudes. However, striking relationships were noted in the quantitative determinations of airborne green and blue-green algae and of fern spore impactions with the varying meteorological conditions of rain, fog-mist, and clear, sunny conditions accompanying the altitude change.
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ItemObservations on the Morphology and Taxonomy of Phycopeltis hawaiiensis King (Chroolepidaceae)(University of Hawaii Press, 1976-04)Observations with light and scanning electron microscopes indicate the foliicolous chlorophyte Phycopeltis hawaiiensis King (Chroolepid aceae) is subcuticular and polystromatic, produces sterile hairs, and induces a distinct wounding, reaction in sub tending host tissue. In comparison, similar observations on Pbycopeltis epiphyton and other Phycopeltis species reveal that, although they are also foliicolous, they are supracuticular and monostromatic. Also, they neither produce sterile hairs nor induce a wounding response in the host leaf. Because the observed characteristics of Phycopeltis hawaiiensis are similar to those of Cepbaleuros virescens and other Cephaleuros species, it is suggested that Phycopeltis hawaiiensis is probably a Cepbaleuros species; however, the absence of reproductive structures renders the designation of a specific epithet problematic.
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ItemReproduction of Acacia koa after Fire(University of Hawaii Press, 1976-04)The abundance, distribution, growth, and mortality of koa (Acacia koa Gray) seedlings after fires were monitored periodically on two burned areas on Oahu for 2.5 years. On one area, seedling density peaked at 95,300/ha 6 months after the fire; 21 months later it had declined to 18,500/ha. On the other area, peak seedling density occurred at 2 months, with 20,400/ha; 26 months later, density had dropped to 7900/ha. Seedlings were not distributed uniformly over the burned areas but were concentrated near koa seed trees. Height growth for seedlings on one area averaged 2.6 cm/mo; on the other, 1.9 cm/mo. Several pathogens were identified, but only the root-crown fungus, Calonectria crotalariae, caused serious damage. More than 50 percent of the mortality on one burn was attributed to it. The regeneration in the burned areas studied indicates that koa will continue to be a component of the forest vegetation.
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ItemPresent Knowledge of the Systematics and Zoogeography of the Order Gorgonacea in Hawaii(University of Hawaii Press, 1976-04)Past knowledge of the order Gorgonacea in Hawaii is based almost exclusively on the collections of the United States Fish Commission steamer Albatross in 1902, which contain 52 species. Recent efforts to investigate the ecology of precious coral have produced a new collection based on 183 dredge hauls and 10 dives with a submersible. This program is collectively referred to as the Sango Expedition. Of 59 species of gorgonians obtained by the Sango Expedition, 13 are considered to be new species and 28 new geographic records, bringing the total number of species considered to be present in Hawaii to 93 species. In contrast to the high diversity of gorgonians in the West Indies and the Indo-West-Pacific, the faunal list in Hawaii must still be considered depauperate. This is especially true in shallow water <75 m), where only one species is known. Although climatic deterioration during the Pleistocene could account for the scarcity of gorgonians in shallow water at the present time, this factor is unlikely to have affected deeper species. Furthermore, one would expect to find a modern complement of an ancestral faun a in shallow water if it had existed, as is true in the case of reef corals. The paucity of gorgonians in Hawaii may be due to isolation, which appears to have been a particularly effective barrier in shallow water. It is suggested that the only accessible route to Hawaii for gorgonians has been in deep water where, in the past, there were numerous stepping stones that may have aided dispersal. Moreover, chemical and physical gradients in deep water are relatively low. Why more deepwater species have not migrated into shallow water in Hawaii may be a reflection of their stenotypic character.
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ItemThermal Tolerance in Tropical Versus Subtropical Pacific Reef Corals(University of Hawaii Press, 1976-04)Upper lethal temperature tolerances of reef corals in Hawaii and at Enewetak, Marshall Islands, were determined in the field and under controlled laboratory conditions. Enewetak corals survived in situ temperatures of nearly 34° C, whereas 32° C was lethal to Hawaiian corals for similar short-term exposures. Laboratory determinations indicate that the upper thermal limits of Hawaiian corals are approximately 2° C less than congeners from the tropical Pacific. Differences in coral thermal tolerances correspond to differences in the ambient temperature patterns between geographic areas.
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ItemObservations on the Behavior and Shell Types of Cypraea moneta (Mollusca, Gastropoda) at Enewetak, Marshall Islands(University of Hawaii Press, 1976-04)Aspects of the ecology and behavior of knobby and smooth Cypraea moneta at Enewetak Atoll, Marshall Islands, are presented. The habitats of C. moneta are described. A series of experiments based on aggregation, feeding, and male-female pairing indicated similarities and differences between the smooth and knobby forms. Smooth morphs follow mucous trails only of other smooth-shelled forms of C. moneta, whereas knobby morphs follow the mucous trails of both knobby and smooth forms. The most preferred alga of the smooth morphs is Jania capillacea, the most abundant species in intertidal areas; and that of the knobby morphs is Schizothrix calcicola, a common subtidal species. Male-female pairs constituted 80 percent of the intertidal samples and 81 percent of the subtidal ones. In addition, smooth and knobby morph distributions were investigated in the Line Islands and elsewhere in Micronesia as well as at Enewetak. In all cases the smooth morph was found in the intertidal zone and the knobby morph in the subtidal.
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ItemSex Ratio, Size at Reproductive Maturity, and Reproduction of the Hawaiian Kona Crab, Ranina ranina (Linnaeus) (Brachyura, Gymnopleura, Raninidae)(University of Hawaii Press, 1976-04)Sex ratio and size at reproduction of Ranina ranina (Linnaeus) in Hawaii were investigated. A sample of 1596 Kona crabs collected over 1 year in Hawaiian waters was examined to determine sex ratio and size at reproduction. Males constituted 55 percent of the overall samples and a similar proportion in all size classes. Males attain a larger maximum size than do females and have mature spermatozoa when their carapace length exceeds 60 mm. Secondary sexual characteristics in the male develop at a carapace length of about 75 mm. Females are ovigerous from May to September. Most ovarian growth occurs between February and May. In May, at the beginning of the spawning season, the number of eggs ovulated is a function of maternal body size: a 25-percent increase in carapace length is associated with a 200-percent increase in number of eggs ovulated. This is not so later in the spawning season (August-September). Larger females appear to ovulate at least twice each season, with the primary effort going into the first ovulation. The smallest 5-mm size class in which at least 50 percent of the females are ovigerous during the spawning season is 70.0-74.9 mm in carapace length. The mean minimum size of ovigerous females is 86 ± 8 mm in this dimension. The spermatheca in females is open to the outside at carapace lengths exceeding 60 mm. Eighteen crabs with carapace lengths less than 65 mm were captured. Half (31.9 mm-42.6 mm) were white in color and were all immature; the remaining half (43.6 mm-61.1 mm) were the usual orange color and all of these exhibited active gametogenesis. This correlation of color with size may be of significance for reproductive behavior.
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ItemDistribution, Morphometry, and Seasonal Biology of the Planktonic Copepods Neocalanus robustior and Neocalanus gracilis in the Pacific Ocean(University of Hawaii Press, 1976-04)
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ItemA New Species of Plesionika (Crustacea, Decapoda, Pandalidae) from the Pacific Coast of Colombia(University of Hawaii Press, 1976-04)
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ItemKeloid in the Gray Reef Shark, Carcharhinus amblyrhynchos(University of Hawaii Press, 1976-04)A gray reef shark, Carcharhinus amblyrhynchos, was captured at Enewetak Atoll, the Marshall Islands, in 1972. Near the right pectoral fin was a large fungating tumor. Microscopically, no evidence of microorganisms or definite malignant transformation was observed, and inflammation and necrosis were minimal. However, the tumor appeared to be a keloid, the first to be reported in sharks.