Pacific Science, vol. 68, no. 3 (2014)

Predominance of Unbalanced Gene Flow from Western to Central North Pacific Colonies of the Black-Footed Albatross (Phoebastria PS68_3.covernigripes)
Haruko Ando, Lindsay Young, Maura Naughton, Hajime Suzuki, Tomohiro Deguchi and Yuji Isagi, 309

Abstract: The Black-Footed Albatross (Phoebastria nigripes) breeds in two remote regions, approximately 4,000 km apart, in the North Pacific. The population in the central North Pacific region (Northwestern Hawaiian Islands), which contains >95% of the total population, is currently stable, although concerns exist about future declines. In contrast, the population in the western North Pacific (Izu and Ogasawara Islands in Japan) is rapidly increasing, and the breeding areas are expanding. To estimate possible gene flow caused by dispersal between populations, we performed genetic analysis on six colonies of Black-Footed Albatross using 10 microsatellite markers. The central and western North Pacific populations were genetically differentiated. However, an estimation of migrants per generation indicated directional dispersal from the western to the central North Pacific. In particular, the population on Kure Atoll, the westernmost atoll in the Hawaiian Islands in the central North Pacific, exhibited weak genetic differentiation from the western North Pacific populations, suggesting frequent immigration from the western North Pacific. The recent expansion of the western North Pacific population may be due to an increase in returning individuals, which may be caused by increased breeding success rates and/or survival rates. Range-wide and long-term monitoring of the Black-Footed Albatross population using genetic markers may help to uncover dispersal dynamics of this highly mobile but philopatric albatross species and to make appropriate conservation decisions in light of environmental changes.

Molecular Phylogenetic Affinities of Scarus obishime Randall & Earle, 1993, Endemic to the Pacific Ocean Archipelago of Ogasawara (Japan)
Kohji Mabuchi and Kaoru Kuriiwa, 321

Abstract: Scarus obishime is a rare parrotfish endemic to the Ogasawara Islands, located in the northwestern Pacific Ocean roughly 1,000 km south of the main Japanese archipelago. It was described as a new species in 1993. Since then it has been speculated to be closely related to Scarus ovifrons occurring on southern coasts of the main Japanese archipelago, but this has never been formally tested. To identify the closest relative of this rare parrotfish, we determined one nuclear (S7 ribosomal protein gene intron 1 [S7I1], ca. 600 bp) and two mitochondrial (control region [CR], ca. 400 bp and 16S rRNA, ca. 600 bp) partial DNA sequences for two specimens of the species and conducted molecular phylogenetic analyses using recently published sequences from 45 of the 52 described species of the genus and 16 of the 18 described species of Chlorurus. Nuclear and mitochondrial sequences were analyzed separately based on results of Basic Local Alignment Search Tool (BLAST) searches using the newly obtained sequences of S. obishime as queries. Phylogenies resulting from two single-region analyses (S7I1 and 16S rRNA) and the concatenation of the two mitochondrial regions (CR + 16S rRNA) supported a close phylogenetic affinity between S. obishime and S. ovifrons. In addition, nuclear (S7I1) analyses demonstrated that the two “East Asian” species formed a robust monophyletic group with the Arabian species Scarus arabicus, whereas mitochondrial data sets significantly rejected monophyly of the three species. This result seems to indicate a partially shared evolutionary history between the “East Asian” and Arabian lineages.

Limnological Characterization of Volcanic Crater Lakes on Uvea Island (Wallis and Futuna, South Pacific)
Ursula Sichrowsky, Robert Schabetsberger, Bettina Sonntag, Maya Stoyneva, Ashley E. Maloney, Daniel B. Nelson, Julie N. Richey and Julian P. Sachs, 333

Abstract: Species composition and vertical distribution of planktonic organisms in Lakes Lalolalo, Lanutavake, and Lano on the Pacific island of Uvea were investigated in relation to physicochemical water column profiles of temperature, conductivity, dissolved oxygen, and pH. The meromictic lakes Lalolalo (maximum depth 88.5 m) and Lanutavake (23.6 m) exhibited a strong chemocline with anoxic conditions below 10 m depth. Mixis was inhibited by sheltered topography, thermal stratification, and in Lalolalo a strong halocline. Crustaceans and rotifers were limited to the oxygenated epilimnion, but diversity and density of ciliates were highest within and below the chemocline. In Lalolalo, euryhaline rotifers dominated the community, reflecting the brackish condition of the lake. Species richness and densities were highest within the shallow lake Lano (3.5 m). On a calm day, hypoxic conditions occurred near the sediment-water interface, but higher oxygen concentrations were observed after heavy winds, indicating occasional mixis. In total, 32 phytoplankton species, 23 ciliate taxa, 18 rotiferan, 1 cladoceran, 1 copepod, and 1 gastrotrich species were identified in the pelagic zones of all three lakes.

Forest Invasion by the African Tulip Tree (Spathodea campanulata) in the Hawaiian Islands: Are Seedlings Shade-Tolerant?
Sébastien Larrue, Curtis Daehler, Franck Vautier and Jennifer L Bufford, 345

Abstract: Native to West Africa, Spathodea campanulata (African tulip tree) is frequently viewed as a shade-intolerant invader. It commonly colonizes roadsides, human-disturbed forests, and abandoned agricultural land in tropical islands, where it can then become dominant in secondary forests. Some authors have suggested that the seedlings may be shade-tolerant and able to establish in closed-canopy forest, but the shade tolerance of seedlings has never been evaluated. We identified tolerated light environments of S. campanulata seedlings in wet forests in Hawai‘i by measuring photosynthetically active radiation (PAR) around naturally occurring seedlings (S. campanulata seedlings in the field were in the range of 50 to 200 µmol photons m-2.sec-1 PAR (i.e., 2.5% to 10% of full sunlight). Among seedlings found growing in shade, minimum saturating light (Ek), determined from chlorophyll fluorescence, averaged 260 µmol photons m-2.sec-1, suggesting that maximum seedling photosynthesis can occur at less than 13% of full sun. Growth rates of young seedlings in shade and sun were comparable. Widespread wind dispersal of seeds, seedling tolerance of low light, and our observations of some S. campanulata saplings establishing in rain forest without recent disturbance suggest that S. campanulata will be a persistent component of Hawaiian lowland rain forests.

Pentalonia nigronervosa Coquerel and Pentalonia caladii van der Goot (Hemiptera: Aphididae) and Their Relationship to Banana Bunchy Top Virus in Micronesia
Julie Anne M. Duay, Ross H. Miller, George C. Wall, Keith S. Pike, and Robert G. Foottit, 359

Abstract: Geographical distribution of Pentalonia nigronervosa and P. caladii, and incidence of banana bunchy top virus (BBTV) were determined in Micronesia. Aphids and plant tissues were collected from banana and nonbanana hosts of Petrtalonia aphids in Palau, Yap, Guam, Rota, Tinian, Saipan, Pohnpei, Kosrae, and Majuro. Aphids were identified based on host species from which they were collected and on morphometric analysis of length of ultimate rostral segment. All plant samples were tested for presence or absence of BBTV using a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). TAS-ELISA analysis confirmed BBTV to be present on Guam, Saipan, and Rota, but BBTV was not detected elsewhere in Micronesia.

Effect of Nestbox Provisioning on Breeding Density of Dollarbirds (Eurystomus orientalis)
Koichi Mine, Akiyo Yamada, Takahiro Nanri, Kenji Maruyama, Hiroshi Nakamura and Masayuki Saigusa, 365

Abstract: The Dollarbird (Eurystomus orientalis) is a secondary cavity-nesting bird that is distributed quite locally in Japan. We carried out extensive surveys across Okayama Prefecture to estimate the number of pairs and found that the major breeding site was holes excavated by woodpeckers in wooden electricity and telegraph poles. Wooden poles were abundant until the 1970s, but most were replaced by concrete poles in the 1980s. Removal of wooden poles containing cavities seriously threatened the breeding population over the first half of the 1990s. In an effort to preserve the Dollarbird population in Japan, beginning in 1991 we provided nestboxes in the village of Kibi (Okayama Prefecture). This resulted in only a small increase in population size over the following 5 yr, but between 1996 and 2001 there was a large annual increase in the breeding population. Increase then leveled off after 2002. Population increase showed a time lag following increase in number of available boxes. Finding new nestboxes may take some time, initially resulting in a low occupation rate for some years after start of box provisioning. Finding of nestboxes by pairs that had bred near Kibi and their subsequent reproduction may have led to a sharp population increase between 1995 and 2002. On the other hand, leveling off of increase in Dollarbird breeding pairs after 2003 may have been directly derived from leveling off of increase in available nestboxes. This suggests a maximum nestbox occupancy rate of 70%–80% in Kibi.

Fishes of Clipperton Atoll, Eastern Pacific: Checklist, Endemism, and Analysis of Completeness of the Inventory
Manon Fourriére, Héctor Reyes-Bonilla, Fabián A. Rodríguez-Zaragoza and Nicole Crane, 375

Abstract: An updated checklist of cartilaginous and bony fishes from reefs and nearby areas around Clipperton Atoll (eastern Pacific) is presented. The register was compiled from field surveys between 1997 and 2012, an exhaustive literature review, and consultation of museum collections and databases. Records were then used to assess completeness of the local fish inventory using six nonparametric rarefaction formulations. A total of 197 species in 62 families was recorded, and of these 106 correspond to reef fishes; most of these are immigrants from the eastern and central Pacific, and only seven species were identified as endemics of the atoll. Estimated level of endemism in reef species (6.6%) is high for the eastern Pacific as a whole but intermediate when compared with data for other oceanic islands of the same region. From nonparametric tests it was estimated that expected number of reef fishes present at Clipperton is 110 + 4 species, and because the difference from the reported number from this new checklist was not significant, we suggest that the current listing is practically complete. Comparisons of completeness of the inventory at Clipperton (~95%) with that reported for fish fauna of the eastern Pacific and worldwide revealed that quality of the current inventory is remarkably high, even in spite of the geographic isolation of the atoll and the still limited scientific data.

Shallow-Water Holothuroids (Echinodermata) of Yap, Federated States of Micronesia
Sun W. Kim, Allison K. Miller, Catherine Brunson, Kristin Netchy, Ronald M. Clouse, Daniel Janies, Emmanuel Tardy and Alexander M. Kerr, 397

Abstract: In December 2002, July 2007, and December 2009, we surveyed the sea cucumber fauna of the western Caroline Island of Yap (Federated States of Micronesia). We collected 37 species of holothuroids, including 32 species of aspidochirotes and five species of apodans. We found all 13 of the previously reported species and 24 new records for the Islands: 19 aspidochirotes and five apodans. At least two of the new records appear to be previously undescribed species. Types of microhabitats and reef zonation were closely correlated with the species distributions of Yapese holothuroids.

Hydropuntia perplexa, n. comb. (Gracilariaceae, Rhodophyta), First Record of the Genus in Hawai‘i
Kimberly Y. Conklin, Daniel C. O’Doherty and Alison R. Sherwood, 421

Abstract: Molecular techniques have proven useful not only in resolving taxonomic and systematic issues among several genera in the red algal family Gracilariaceae but also in the rapid identification of cryptic invasive species (e.g., Gracilaria vermiculophylla and G. parvispora). In Hawai‘i (U.S.A.), Gracilaria is both economically and culturally important, with G. coronopifolia being highly prized. Molecular analyses of chloroplast rbcL and mitochondrial COI sequence data indicate that recent collections of Hawaiian “ G. coronopifolia” are polyphyletic and consist of two species representing two different genera, Gracilaria and Hydropuntia. This is the first formal record of the genus Hydropuntia in Hawai‘i. These results also reveal that collections of Hawaiian Hydropuntia sp. are closely related to an Australian alga, Gracilaria perplexa, with both taxa belonging to a strongly supported Hydropuntia clade, and suggest that both cases represent cryptic invasions. We formally propose the transfer of G. perplexa to Hydropuntia and also recognize Hawaiian specimens of Hydropuntia as that species: Hydropuntia perplexa (Byrne & Zuccarello) Conklin, O’Doherty & A. R. Sherwood, n. comb.

Presence of a Halophila baillonii Asch. (Hydrocharitaceae) Seagrass Meadow and Associated Macrofauna on the Pacific Coast of Costa Rica
Jimena Samper-Villarreal, Amandine Bourg, Jeffrey A. Sibaja-Cordero and Jorge Cortés, 435

Abstract: Seagrasses in the eastern Pacific are mainly confined to temperate and subtropical regions of North America, with limited reports of presence in Central America and Chile. We report a unique monospecific meadow of Halophila baillonii for the Eastern Tropical Pacific in Golfo Dulce, southern Pacific coast of Costa Rica. This report constitutes the first sighting of seagrasses from the Pacific coast of Costa Rica since disappearance of the only reported seagrass meadow, of Ruppia maritima and Halophila baillonii, in 1996. Twenty sediment cores (5 cm diam., 15 cm deep) were taken at 10 locations for characterization of seagrass and associated macrofauna, grain size distribution, and carbonate analysis. Area of the seagrass meadow was 884 m-2, foliar shoot density was 4,841 ± 3,433 shoots m-2, and biomass was 30.7 ± 16.3 g DW m-2. Invertebrate fauna were mainly infaunal, dominated by polychaetes. Seven invertebrate species are new records for Costa Rica and 13 for Golfo Dulce. Further research is needed to elucidate dynamics and ecological drivers of seagrasses in the Eastern Tropical Pacific.

Association Affairs, 445


Comments are closed.