Pacific Science Volume 28, Number 2, 1974
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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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Item Geophysical Observations between Hawaii and Australia(University of Hawai'i Press, 1974-04) Johnson, G.L.; Egloff, J.; Hemler, L.G.A 3.5 kHz high resolution profiling system and a sparker seismic system were utilized along a geophysical traverse from Hawaii to Australia. The delineated sediments range from a total lack of sediment cover on the axis of Woodlark Basin spreading center to a thick pile of biogenic debris beneath the equatorial high productivity zone. The calcareous oozes of the western Darwin Rise and Solomon Rise, the interbedded clays, silts, and volcanic debris of the Hawaiian Arch, and local sediment pockets near topographic highs are discerned by the 3.5 kHz energy source as stratified. The nonfossiliferous deep-sea lutites (red clays) and siliceous oozes in the deeper portion of the central Pacific appear as acoustically transparent sediments. Erosion and redeposition of sediments either in the recent past or at the present time are apparent on the Hawaiian Arch, near the Line Islands, in the central Pacific from 160° to 175° E, between the 2,300 and 2,400 m isobath on the Solomon Rise and along the 4,000 m isobath in the Coral Sea.Item Soil Algae of Eniwetok Atoll, the Marshall Islands(University of Hawai'i Press, 1974-04) Arvik, Jon H.; Willson, Dan L.Item Actiniogeton sesere (Coelenterata, Actiniaria) in Hawaii(University of Hawai'i Press, 1974-04) Dunn, Daphne FautinA species of sea anemone found in shallow water areas of southern Kaneohe Bay, Oahu, but never before reported from Hawaii, is described. It is identified as Actiniogeton sesere, previously recorded and described from the Torres Straits (Haddon and Shackleton 1893).Item Radianthus papillosa (Coelenterata, Actiniaria) Redescribed from Hawaii(University of Hawai'i Press, 1974-04) Dunn, Daphne FautinThe shallow water sea anemone that was described by Verrill (1928) as Macranthea cookei from specimens collected in Hawaii is redescribed and synonymized with Radianthus papillosa, first described by Kwietniewski (1898) as Stichodactis papillosa from Ambon.Item Euchaeta marina (Prestandrea) (Copepoda, Calanoida) and Two Closely Related New Species from the Pacific(University of Hawai'i Press, 1974-04) Bradford, Janet M.Item The Echinoids of Easter Island (Rapa Nui)(University of Hawai'i Press, 1974-04) Fell, F JulianThe known echinoid fauna of Easter Island now comprises seven species. Four of them, Tripneustes gratilla, Echinostrephus sp., Clypeaster reticulatus, and Brissus agassizii are reported here from Easter Island for the first time, Tripneustes gratilla apparently being represented by a previously unknown variant. The value of the pedicellariae and the heavily plated peristome as specific differences in the genus Tripneustes is questioned. Comparison of Easter Island material with specimens from other parts of the Pacific supports the synonymy of Brissus meridionalis with Brissus agassizii. One of the previously reported species, Echinometra insularis, is herein restricted to Easter Island, reports of its occurrence elsewhere being based upon erroneous identifications. The reported occurrence of Diadema mexicanum at Easter Island is discounted.Item Effect of Elevated Temperature on the Metabolic Activity of the Coral Reef Asteroid Acanthaster planci (L.)(University of Hawai'i Press, 1974-04) Yamaguchi, MasashiStandard rate of oxygen uptake in the coral reef asteroid Acanthaster planci(L.) was determined for the temperature range of 25° to 33° C and a metabolic rate-temperature (M-T) curve was drawn. Acanthaster planci is a metabolic conformer. The rate of oxygen uptake increased with increase of temperature to 31 ° C. The rate decreased at 33° C, which is slightly above the ambient temperature for the laboratory-reared Acanthaster planci tested. The decrease indicates a disturbance in the metabolic activity due to the elevated temperature. The incipient thermal death point for the asteroid was estimated to be near 33° C, at which temperature the animals did not maintain a normal behavior in feeding and resting cycles. Increasing modification in thermal conditions by human activity would pose a hazard to the maintenance of coral reef communities if Acanthaster planci represents metabolic conformer invertebrates with narrow tolerance to elevated temperature.Item Growth of Juvenile Acanthaster planci (L.) in the Laboratory(University of Hawai'i Press, 1974-04) Yamaguchi, MasashiSeven juvenile Acanthaster planci were reared from fertilized eggs to sexual maturity in 18 to 21 months in the laboratory. Four-month-old juveniles, about 8 mm in total diameter, began to transform into coral predators from the prior herbivore stage that fed on encrusting coralline algae. The transition period lasted for about 1 month. Many juveniles were injured by coral polyps, which had been offered as food, shortly after the transitional period. Except for severely injured ones, all the coral-feeding juveniles grew steadily after recovering from the injuries and, when the animals were well fed, their growth curve was sigmoid. Mean growth coefficient for the early coral-feeding juveniles, growing exponentially, was nearly half that of the previous algae-feeding stage, and the coefficient value reduced rapidly as the juvenile grew near to maturity. Acropora nasuta and Pocillopora damicornis both sustained full growth of juveniles. However, the juvenile Acanthaster killed about twice as much coral mass of Acropora nasuta as of Pocillopora damicornis to gain the same amount of weight.Item Geographic Variation in the Central Pacific Halfbeak, Hyporhamphus acutus (Gunther)(University of Hawai'i Press, 1974-04) Collette, Bruce B.Hyporhamphus acutus (Gunther) is distinguished from other Central Pacific species of Hyporhamphus by its long upper jaw, long anal fin base (longer than dorsal base), and shape of its preorbital lateral line canal. Two subspecies are recognized: Hyporhamphus acutus acutus (Gunther) with fewer vertebrae and fin rays inhabits the chain of islands from Wake Island and the Marshall Islands in the northwest to the Tuamotu Archipelago and Easter Island in the southeast; Hyporhamphus acutus paciftcus (Steindachner) with more vertebrae and fin rays is found in the Hawaiian Islands and at Johnston Island. Hemiramphus furcatus Philippi from Easter Island and Odontorhamphus chancellori Weed from the Cook Islands are placed in the synonymy of Hyporhamphus acutus acutus.Item The Ophidioid Fish Genus Luciobrotula in the Hawaiian Islands(University of Hawai'i Press, 1974-04) Cohen, Daniel M.