Pacific Science, Volume 60, Numbers 4, 2006
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ItemIndex to Volume 60 : Subject Index(Honolulu, University of Hawaii Press, 2006-10)
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ItemIndex to Volume 60 : Author Index(Honolulu, University of Hawaii Press, 2006-10)
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ItemAssociation Affairs(Honolulu, University of Hawaii Press, 2006-10)
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ItemFirst Record of the Labrid Fish Cymolutes praetextatus from the Hawaiian Islands.(Honolulu, University of Hawaii Press, 2006-10)The labrid fish Cymolutes praetextatus, previously known from East Africa to the Society Islands but not east of the Marshall Islands in the North Pacific, is reported from the Hawaiian Islands from two specimens collected in 18 m and an underwater photograph taken in 27 m. One of the color descriptions by Jordan and Evermann in 1905 in their species account of C. lecluse indicates that they had a specimen of praetextatus.
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ItemEvidence for Sequential Hermaphroditism in Sabellastarte spectabilis (Polychaeta: Sabellidae) in Hawai‘i.(Honolulu, University of Hawaii Press, 2006-10)Understanding the reproductive characteristics of Sabellastarte spectabilis (Grube, 1878), an economically important polychaete worm collected forthe aquarium trade, is essential to the development of artificial propagation and conservation of coral reefs. The purpose of this study was to determine whether S. spectabilis is hermaphroditic. Using histological techniques, 180 individuals were examined for gametes. Gametes were present only in abdominal segments. Primary oocytes were 7–8 mm in diameter in histologically prepared sections. Sperm appeared as round black dots about 2 mm in diameter on histologically prepared slides. Most individuals sampled had only one type of gamete in the coelom, but both eggs and sperm were seen in the coelom of 15% of individuals, demonstrating the occurrence of hermaphroditism in Hawaiian populations of S. spectabilis. The sex ratio of males to females was skewed significantly toward males in both the small (6–8 mm diameter) and medium (9–10 mm diameter) sized worms. Among the largest worms (11–13 mm diameter), the sex ratio did not diverge significantly from 1: 1. There was a significantly higher proportion of hermaphrodites (30%) in the large size class. Worms of unknown gender, although present in all size classes examined, were most frequent (33%) in the medium size class. These
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ItemJaneke D. Impact of Post-typhoon Hunting on Mariana Fruit Bats (Pteropus mariannus).(Honolulu, University of Hawaii Press, 2006-10)We examined the abundance of Mariana fruit bats (Pteropus mariannus Desmarest) on the Pacific islands of Rota and Guam before and after a severe typhoon in December 2002. After the typhoon, bat abundance declined by 70% on Rota. On Guam, bat abundance initially increased by ca. 100 individuals (103%), perhaps due to immigration from Rota, but then declined an average of 32% from pretyphoon levels for the remainder of 2003. An increase in posttyphoon hunting pressure represents at least a partial cause for the decline observed on Rota. Interviews with 29 suspected poachers on the island revealed a 34% increase in bat harvest from 2002 to 2003. Hunting of bats is rare on Guam because access to their remaining habitat is restricted by the U.S. military. However, juvenile bats are preyed on by introduced brown tree snakes (Boiga irregularis Bechstein) on Guam to such an extent that little to no withinisland recruitment occurs. We therefore suggest that the brief increase and subsequent decrease in bat abundance on Guam was due to interisland movements, a reduction in the source population (Rota), and/or changes in roosting patterns on Guam. Rota is vital to recovery prospects for P. mariannus in the southern Mariana Islands because it holds the only viable population in this part of the archipelago. If the species is not conserved, forest ecosystems may suffer because P. mariannus is almost certainly an important seed disperser and pollinator on these depauparate islands. We recommend that agencies responsible for managing hunted fruit bat populations make special efforts to prevent illegal hunting after severe typhoons.
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ItemKiller Whales in Hawaiian Waters: Information on Population Identity and Feeding Habits(Honolulu, University of Hawaii Press, 2006-10)Killer whales (Orcinus orca) have only infrequently been reported from Hawaiian waters, and most of what is known about killer whales worldwide comes from studies in coastal temperate waters. Here we present 21 records of killer whales from within the Hawaiian Exclusive Economic Zone between 1994 and 2004. Killer whales were recorded nine months of the year, most around the main Hawaiian Islands. Although there were more records than expected during the period when humpback whales are abundant around the Islands, there is likely an increase in sighting effort during that period. Killer whales were documented feeding on both a humpback whale and cephalopods, and two species of small cetaceans were observed fleeing from killer whales. Although it is possible that there are both marine mammal–eating and cephalopod-eating populations within Hawaiian waters, it seems more likely that Hawaiian killer whales may not exhibit foraging specializations as documented for coastal temperate populations. Saddle patch pigmentation patterns were generally fainter and narrower than those seen in killer whales from the temperate coastal North Pacific. Analysis of skin samples from two animals indicated two mitochondrial haplotypes, one identical to the ‘‘Gulf of Alaska transient 2’’ haplotype (a mammal eating form), and the other a new haplotype one base different from haplotypes found for mammal-eating killer whales in coastal Alaskan waters.
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ItemNearshore Distribution and an Abundance Estimate for Green Sea Turtles, Chelonia mydas, at Rota Island, Commonwealth of the Northern Mariana Islands.(Honolulu, University of Hawaii Press, 2006-10)Seventy-three green turtles, Chelonia mydas (Linnaeus, 1758), were observed in 84 sightings along 28 transects covering 67% of Rota’s shoreline and outer reef perimeter in the Commonwealth of the Northern Mariana Islands. No other sea turtle species were encountered. Juvenile turtles of various sizes dominated in all surveyed environments, and observations of turtles with estimated straight carapace lengthsa40 cm suggested recent and continuing recruitment at Rota. Distribution of turtles appeared temporally stable when compared with previously reported observations and data, with turtle concentrations highest along northeast, east, and southeast coasts of the island. Approximately 118 turtles were projected to inhabit nearshore habitats at Rota. Although this population may appear minor and indistinct compared with those at nearby Tinian and Saipan, continued monitoring would be useful for comparison of Mariana Islands trends. Thirty-five species of cyanophytes, algae, and a sea grass noted as green turtle forage in other world regions were identified at Rota in this and previous surveys.
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ItemRapid Assessment of Nonindigenous Marine Species on Coral Reefs in the Main Hawaiian Islands(Honolulu, University of Hawaii Press, 2006-10)Coral reefs at Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i were surveyed using a rapid assessment method for marine nonindigenous and cryptogenic species commonly found in Hawaiian harbors and embayments with restricted circulation. In 41 sites surveyed by rapid assessment 26 nonindigenous and cryptogenic species (three algae, 19 invertebrates, and four fishes) were recorded from a total of 486 total taxa identified, and 17 of the nonindigenous and cryptogenic species occurred at only one or two sites. No more than six nonindigenous and cryptogenic species were recorded at any one site, and 21 of the 41 sites had fewer than three. By comparison, laboratory identification of samples collected from seven of the sites closest to harbors found 6–23 nonindigenous and cryptogenic species per site. Values for nonindigenous and cryptogenic species from rapid assessment were compared with factors potentially influencing spread and proliferation of introduced marine species. These factors included distances from harbors, boat-launching ramps, stream mouths, and shorelines; degree of shoreline urbanization; quantity of artificial surfaces in the water; reef condition and isolation from the open ocean; and native species richness. A best subsets regression model explained over 65% of the variance in nonindigenous and cryptogenic species from two predictor variables and their interaction: isolation from the open ocean and number of native taxa, with most of the variance explained by a highly significant relationship of nonindigenous and cryptogenic species with isolation from open-ocean conditions.
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ItemArbuscular Mycorrhizae Effects on Growth of Two Hawaiian Species:Indigenous Osteomeles anthyllidifolia (Rosaceae) and Invasive Psidium cattleianum (Myrtaceae).(Honolulu, University of Hawaii Press, 2006-10)Two important plant species of Hawai‘i, the indigenous Osteomeles anthyllidifolia (Sm.) Lindl., a component of Hawai‘i’s most endangered habitat, and the highly invasive Psidium cattleianum Sabine were grown with or without arbuscular mycorrhizal fungi in a soilless mix at different soil solution phosphorus (P) levels. At P levels similar to those in the field (0.007 mg P/liter), shoot biomass of inoculated plants of O. anthyllidifolia was 189% greater than that of controls, and that of P. cattleianum was 93% greater. Root weight of O. anthyllidifolia and leaf-tissue P of both species also were significantly higher in inoculated plants. At a higher concentration of soil-solution P (0.020 mg P/liter), inoculated plants of O. anthyllidifolia had 176% more biomass than controls, and those of P. cattleianum had 49% more. In a growth medium with soilsolution P equivalent to that of good agricultural soil (0.200 mg P/liter), inoculated plants of O. anthyllidifolia were 101% larger than controls. Results suggest that presence of arbuscular mycorrhizal fungi is of vital importance to establishment of O. anthyllidifolia in Hawaiian soils and that their absence may limit P. cattleianum invasion of sites that are highly deficient in available P.