Pacific Science 61, no. 1
Introducing a New Series: Biology and Impacts of Pacific Island Invasive Species
David R. Clements and Curtis C. Daehler, 1-1
Biology and Impacts of Pacific Island Invasive Species. 1. A Worldwide Review of Effects of the Small Indian Mongoose, Herpestes javanicus (Carnivora: Herpestidae)
Warren S. T. Hays and Sheila Conant, 3-16
The small Indian mongoose, Herpestes javanicus (E. Geoffroy Saint-Hilaire, 1818), was intentionally introduced to at least 45 islands (including 8 in the Pacific) and one continental mainland between 1872 and 1979. This small carnivore is now found on the mainland or islands of Asia, Africa, Europe, North America, South America, and Oceania. In this review we document the impact of this species on native birds, mammals, and herpetofauna in these areas of introduction.
Vegetation History of Laysan Island, Northwestern Hawaiian Islands
J. S. Athens, J. V. Ward, and D. W. Blinn, 17-37
Paleoenvironmental investigations were undertaken on Laysan Island in the remote Northwestern Hawaiian Islands to investigate its flora before historical observations. Substantial impacts occurred to the island as a result of late nineteenth- and early twentieth-century guano mining, commercial feather collecting, and denudation of vegetation by feral rabbits. An account of Laysan’s historically known vegetation is presented, followed by discussion of results from the investigation of a 16.41-m sediment core from Laysan’s central hypersaline lake. The 7,000-year pollen and seed record, besides indicating the former importance of Pritchardia palms on Laysan, showed the former presence of seven previously unknown taxa, only four of which could be identified. Diatom analysis indicated fresh to brackish lake water during the early Holocene, a finding supported by the mollusk assemblage. Diatom diversity gradually decreased over time until there is a near monoculture, with types indicating a gradual increase of salinity. Hypersaline conditions were first recognizable near the top of the sequence with the appearance of Artemia zooplankton. Generally wetter conditions seem to have characterized the island before about 5,150 yr B.P., with drier conditions thereafter. The pollen record also suggests two possibly very brief periods of much drier conditions, conceivably related to El Niño–Southern Oscillation episodes.
Avifauna of Lehua Islet, Hawai‘i: Conservation Value and Management Needs
Eric A. VanderWerf, Ken R. Wood, Chris Swenson, Maya LeGrande, Heather Eijzenga, Ronald L. Walker, 39-52
We conducted surveys from 2002 to 2005 and compiled historical information on the avifauna of Lehua Islet, Hawai‘i, to assess its conservation status and management needs. Thirty-five bird species have been observed on Lehua since 1931, including 18 seabirds endemic or indigenous to the Hawaiian Islands, one resident indigenous waterbird, six migratory waterbirds, and 10 alien land birds. We observed 29 of these species during surveys from 2002 to 2005, 13 of which had not been recorded on the islet previously. Over 25,000 pairs of eight seabird species were documented to breed on Lehua, including previously unknown breeding colonies of Black-footed Albatross (Phoebastria nigripes) and Laysan Albatross (P. immutabilis), and the largest breeding colonies of Brown Booby (Sula leucogaster) and Red-footed Booby (S. sula) in the Hawaiian Islands. Remains of a Newell’s Shearwater (Puffinus auricularis newelli) chick and a Band-rumped Storm-Petrel (Oceanodroma castro) chick were found, demonstrating that those species have nested on the islet and probably still do. The nesting season varied among species, with most species breeding from March to August, and at least one species breeding in every month. Predation by alien Polynesian rats (Rattus exulans) and Barn Owls (Tyto alba) is the most serious threat to nesting seabirds on Lehua. Sediment beneath a Barn Owl roost contained hundreds of bones from a variety of bird species, including Brown Noddy (Anous stolidus), which has been extirpated from the islet. Feral rabbits (Oryctolagus cuniculus) are suppressing vegetation that could provide additional nest sites for Red-footed Boobies and help prevent erosion and burying of seabird burrows. The most urgent management needs on Lehua are eradication of alien Polynesian rats, alien Barn Owls, and feral rabbits. Rocky offshore islets like Lehua may become increasingly important in seabird conservation because their small size makes it more feasible to manage threats, and because they are less likely to be affected by increases in sea level associated with climate change.
Molecular Systematics of the Endangered O‘ahu Tree Snail Achatinella mustelina: Synonymization of Subspecies and Estimation of Gene Flow between Chiral Morphs
Brenden S. Holland, Michael G. Hadfield, 53-66
The single-island endemic O‘ahu tree snail Achatinella mustelina Mighels, 1845 is an endangered species with dimorphic shell chirality, persisting in small populations restricted to upper-elevation native forest in the Wai‘anae Mountains. We used an intraspecific molecular phylogeny (n = 21 populations) to evaluate the validity of subspecies, most of them introduced by Welch in 1938 on the basis of shell characters, by determining whether the nominal subspecies examined correspond to detectable molecular partitions and to examine the possibility that opposing shell chirality acts as a reproductive isolating mechanism. We mapped the nominal subspecies and shell chiralities onto a mitochondrial DNA (mtDNA) phylogram based on 86 cytochrome c oxidase I gene fragments and the extant range of the species. Although clear genetic breaks and haplotype clusters with well-defined boundaries exist and correspond to topographic features, each of the five monophyletic clades in the gene tree contains multiple supposed subspecies, haplotypes are shared between different subspecies, and none of the 13 nominal subspecies exhibits monophyly. Furthermore the mtDNA clades in the gene tree do not correspond to observed patterns in shell chirality, and both chiralities occur in all clades. Thus, the subspecies are not taxonomically valid and have no relevance for conserving genetic diversity, and chirality differences do not appear to impart a reproductive barrier in this species. Therefore, all subspecies of A. mustelina are herein synonymized.
Diversity and Biogeography of the Scleractinian Coral Fauna of Easter Island (Rapa Nui)
Peter W. Glynn, Gerald M. Wellington, Bernhard Riegl, Donald B. Olson, Eric Borneman, Evie A. Wieters, 67-90
Three surveys at Easter Island (Rapa Nui) spanning the period 1999–2005, and examination of private and museum collections, have revealed a depauperate zooxanthellate scleractinian fauna. Collections were all made off island shelf exposures, from tide pools to 70 m with scuba, and by dredging to 100 m. With synonymies, reassignments, and two new records in the families Pocilloporidae and Faviidae, the Easter Island coral fauna now comprises 13 species. Pocilloporid and poritid coral abundances were generally high on all island shelves protected from southern swells. A cluster analysis of the coral fauna relationships of 19 south, central, and far-eastern Pacific sites indicates a strong affinity between those of Easter Island and the far-eastern Pacific equatorial region (e.g., Colombia, Ecuador, Panamá, and the Galápagos Islands). The precipitous drop in coral species richness from the Pitcairn Island group (61 species) to Easter Island suggests the presence of a dispersal barrier between these two remote southeastern Pacific areas, separated by ~1,800 km of deep ocean waters. Consideration of the surface circulation based on satellite-tracked surface drifters confirms this conclusion. Surface currents are from east to west along the topography on which Easter and Sala-y-Gómez Islands sit, suggesting a substantial barrier to recruitment from the west.
The Crinoid Fauna (Echinodermata: Crinoidea) of Palau
Charles G. Messing, 91-111
Taxonomic revisions and a recent survey using scuba place the number of shallow-water (<50 m) crinoid species known from Palau at 22. Five are new records: Clarkcomanthus littoralis, Comanthus suavia, Alloeocomatella pectinifera, Oxycomanthus comanthipinna, and O. exilis. A submersible survey (to 310 m) recovered five additional new records, four of which are the first representatives of their families from Palauan waters: Eudiocrinus venustulus (Eudiocrinidae), Glyptometra sp. (Charitometridae), Cosmiometra belsuchel Messing, n. sp. (Thalassometridae), and Porphyrocrinus verrucosus (Phrynocrinidae), the first stalked crinoid recorded from Palau. Two of the three specimens of the latter have regenerating crowns, suggesting that this species may be subject to substantial predation or an unstable environment.
Feeding preferences of the crown-of-thorns sea star, Acanthaster planci (L.), were studied in a series of laboratory-based feeding trials wherein sea stars were provided with equal availability of six different coral species. The order in which corals were consumed was then used to ascertain feeding preferences. Crown-of-thorns sea stars exhibited strong and consistent feeding preferences across replicate feeding trials. The most readily eaten coral species was Acropora hyacinthus, followed by A. gemmifera, A. nasuta, A. formosa, Stylophora pistillata, Montipora undata, and Pocillopora damicornis. Crown-of-thorns sea stars also consumed Goniopora lobata, Fungia fungites, Goniastrea retiformes, and Pavona cactus but only after all Acropora and Montipora (Family Acroporidae) as well as Pocillopora and Stylophora (Family Pocilloporidae) were eaten. The least preferred corals were Favites abidita, Porites lobata, Symphyllia recta, Echinopora horrida, and Porites cylindrica. Of these, P. cylindrica was never eaten in any of the feeding trials in which it was offered. Observed feeding preferences substantiate findings from previous studies, where corals from the families Acroporidae and Pocilloporidae were preferred over all other corals. Further research is required to assess the underlying basis of feeding preferences of A. planci, but this study confirms that these starfish readily distinguish between different corals and have innate preferences for certain species. Still, most corals were eventually consumed, showing that when food is limited (during population outbreaks) A. planci is likely to consume virtually all different coral species, causing extreme devastation to coral reef ecosystems.
Age and Growth of the Finescale Triggerfish, Balistes polylepis (Teleostei: Balistidae), on the Coast of Mazatlán, Sinaloa, Mexico
Ithandehui Barroso-Soto, Emerita Castillo-Gallardo, Casimiro Quiñonez Velázquez, Ramón E. Morán-Angulo, 121-127
To estimate the weight-length relationship, determine age, and describe growth of the finescale triggerfish, Balistes polylepis Steindachner, 1876, 552 specimens were measured and weighed, and 318 first dorsal spines were collected from the artisanal catch in Mazatlán, Sinaloa, Mexico, between October 2000 and October 2001. Fish ranged between 16 and 53 cm in total length (TL), and distribution was biased toward small sizes. Age was assigned according to the number of opaque-hyaline bands in spines, identifying seven age groups (1–7), with age groups 2, 3, and 4 jointly representing over 80% of the collection. The von Bertalanffy model was adequately fitted to the age-TL data and accounted for 91% of the variation in TL. Parameters were estimated as TL∞ = 55:8 cm; K = 0.17 yr -1, and t0 = 1:7 yr. The total weight (TW) of the finescale triggerfish ranged between 75 and 2,200 g, and the TW-TL relationship showed a negative allometric growth (b = 2:7). These results are the first reported for age and growth of this species.
Laboratory Observations of Reproduction in the Deep-Water Zoarcids Lycodes cortezianus and Lycodapus mandibularis (Teleostei: Zoarcidae)
Lara Annette Ferry-Graham, Jeffrey C. Drazen, Veronica Franklin, 129-139
The first observations of reproduction and associated behaviors in captive bigfin eelpout, Lycodes cortezianus, and pallid eelpout, Lycodapus mandibularis, are reported here. One Lycodes cortezianus pair produced 13 transparent and negatively buoyant eggs that were approximately 6 mm in diameter. These were laid on a hydroid-covered rock. The development period was about 7 months, and the young that emerged were approximately 2 cm in total length. An additional captive pair also exhibited mating behavior as the male repeatedly nudged the female and the pair produced a burrow under a sponge; however the male died before any mating. Two gravid female Lycodapus mandibularis were captured and laid between 23 and 46 eggs that were about 4 mm in diameter. These were released on the sandy substrate after the females moved the sand about the tank, and the eggs were negatively buoyant. These eggs were all unfertilized. Additional burrowing behavior was observed from other captive individuals, but no eggs were subsequently produced. Taken together, our observations suggest that burrowing or use of other protective structures is a reproductive behavior of central importance to zoarcids. Contrary to some earlier hypotheses, even midwater species likely return to the sediment to burrow and/or deposit eggs. This behavior means that field data regarding reproduction in this family will continue to be difficult to obtain, and the contribution of further study in laboratory situations should not be underestimated.
Redescription of Yirrkala gjellerupi, a Poorly Known Freshwater Indo-Pacific Snake Eel (Anguilliformes: Ophichthidae)
John E. McCosker, David Boseto, Aaron Jenkins, 141-144
Yirrkala gjellerupi (Weber & de Beaufort, 1916), unknown since the brief and unfigured original description of the holotype from New Guinea, is herein diagnosed, described, and illustrated, based on specimens recently captured in a Fijian freshwater stream. Other eels collected there and nearby include Anguilla megastoma, A. obscura, Lamnostoma kampeni, and an unidentified moringuid. Living far from the sea is very atypical for an adult ophichthid.
New Species of Extinct Rails (Aves: Rallidae) from Archaeological Sites in the Marquesas Islands, French Polynesia
Jeremy J. Kirchman, David W. Steadman, 145-163
We examined 53 bones of rails (Rallidae), previously referred to Gallirallus n. spp., from archaeological sites on four islands in the Marquesas Islands, French Polynesia. We describe three new, extinct, flightless species of Gallirallus: G. roletti (Tahuata), G. gracilitibia (Ua Huka), and G. epulare (Nuku Hiva). Two bones from Hiva Oa, although probably representing another extinct species of Gallirallus, are regarded as an inadequate basis for describing a species. At first human contact, the genus Gallirallus probably included many scores if not hundreds of flightless species on islands from the far western Pacific (Okinawa, Philippines, Halmahera) eastward across most of Oceania. As currently understood, the Marquesas Islands represent the eastern range limit of Gallirallus.
Pacific Science 61, no. 2
Conservation Status of the Endemic Bees of Hawai‘i, Hylaeus (Nesoprosopis) (Hymenoptera: Colletidae)
Karl N. Magnacca, 173-190
The 60 species of native Hylaeus bees in the Hawaiian Islands are important pollinators in native ecosystems, but they have been almost completely ignored in conservation studies. The only previous assessment of the conservation status of the individual species was not based on recent collections. Here I report on conservation status of all known species, based on collections made from 1999 to 2002. Species are arranged into six categories according to degree of threat, and species considered to be threatened are discussed individually. Five species have not been collected recently from one or more islands from which they are historically known, seven are restricted to endangered habitat, 10 are considered to be very rare and potentially endangered, and 10 have not been collected recently and could be extinct. With such a high proportion of rare species and the importance of Hylaeus species as pollinators, further work on their ecology is needed.
Reproductive Biology of the Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae), during Colonization of Guam and Comparison with That in Their Native Range
Julie A. Savidge, Fiona J. Qualls, and Gordon H. Rodda, 191-199
Since their introduction to Guam shortly after World War II, brown tree snakes, Boiga irregularis (Merrem), have seriously impacted the biota and human population of the island. Understanding the biology of this exotic species will likely be important to the success of control programs. We compared the reproductive biology of 782 B. irregularis caught on Guam during the 1980s with results from published studies of native-range populations. Average and maximum sizes of mature snakes on Guam were larger than those from Australian populations. The majority of female brown tree snakes matured at snout-vent lengths (SVLs) of 910–1,025 mm, and most males matured at SVLs of 940–1,030 mm on Guam. Based on growth rates from the early 1990s on Guam, sexual maturity is estimated to occur during a snake’s third or fourth year. Only one female (0.3%) in our data set had oviductal eggs. Clutch size was estimated at 4.3 (SD = 2.2), based on large vitellogenic ovarian follicle (≥30 mm in length) and oviductal egg counts. Unlike their Australian counterparts, the Guam population reproduced year-round. Our data offer insights into the likely reproductive patterns of brown tree snakes should they infest other islands in the Pacific region.
Consistent Frequency of Color Morphs in the Sea Star Pisaster ochraceus (Echinodermata: Asteriidae) across Open-Coast Habitats in the Northeastern Pacific
Peter Raimondi, Raphael D. Sagarin, Richard Ambrose, Christy Bell, Maya George, Steven Lee, David Lohse, C. Melissa Miner, and Steven Murray, 201-210
The sea star Pisaster ochraceus (Brandt, 1835) is among the most conspicuous members of northeastern Pacific rocky-shore fauna due to its dramatic color variation, ranging from bright yellowish orange to brown to deep purple. Despite a large body of ecological and developmental biology information on P. ochraceus, few studies have rigorously examined color patterns or their causes across its geographic range. We used thousands of observations of sea star color and size taken from southern California to northern Oregon to show that the frequency of orange sea stars is approximately 20% with little variation across a broad latitudinal band. However, the frequency of orange sea stars in a population increases with the size of the animals in most populations. We consider several alternative hypotheses for these color patterns but find that the most parsimonious explanation is that adult color is a selectively neutral genetic trait that expresses itself ontogenetically. These novel findings point to the need for renewed study of the basic biology of this key ecological species.
Interspecific Spawning between a Recent Immigrant and an Endemic Damselfish (Pisces: Pomacentridae) in the Hawaiian Islands
Karen P. Maruska and Kimberly A. Peyton, 211-221
The Indo-Pacific damselfish Abudefduf vaigiensis (Quoy & Gaimard, 1825) was first observed in the Hawaiian Islands in the early 1990s and is now clearly established as a breeding population in the Islands. Sightings of fish with color patterns intermediate between those of A. vaigiensis and the very similar endemic Hawaiian sergeant, Abudefduf abdominalis (Quoy & Gaimard, 1825), suggest that hybridization of the two has occurred naturally. This study provides direct evidence of crossbreeding from observations and video footage of two separate spawnings in nearshore waters of O‘ahu and a third spawning in a public aquarium display tank. Reproductive behaviors were similar in intra- and interspecific spawning. However, one important difference was the absence of courtship by the male A. abdominalis toward the female A. vaigiensis in the interspecific spawnings. Instead, the female A. vaigiensis initiated spawning and the male A. abdominalis remained to fertilize, guard, fan, and clean the hybrid clutch along with a previous clutch until the embryos hatched. Embryos collected from one hybrid clutch showed normal embryonic development and subsequently hatched to produce viable swimming larvae. These observations represent a rare example of interspecific spawning in the damselfish family (Pomacentridae) and an exceptional opportunity to study hybridization and introgression in a wild population of coral reef fishes.
Genetic Population Structure of the Hawaiian Alien Invasive Seaweed Acanthophora spicifera (Rhodophyta) as Revealed by DNA Sequencing and ISSR Analyses
Daniel C. O’Doherty and Alison R. Sherwood, 223-233
Acanthophora spicifera (Vahl) Børgesen is the most widespread and invasive alien macroalga on coral reefs throughout the main Hawaiian Islands. This alga disperses from harbors and ports to coral reefs throughout the state, producing high quantities of biomass that affect a wide range of reef flora and fauna. Population samples of A. spicifera from across the main Hawaiian Islands were collected and compared through two kinds of analyses: DNA sequencing (based on a variable region of the nuclear large subunit ribosomal RNA gene, and the mitochondrial cox 2-3 spacer region) and fragment techniques (Inter-Simple Sequence Repeats [ISSRs]). DNA sequencing revealed no variation for the two markers, even when collections from other areas of the Pacific and Australia were included. In contrast, ISSR analyses revealed highly structured Hawaiian populations of A. spicifera with a substantial range of both within- and among-population variation, with individual plants forming discrete clusters corresponding to geographic locality.
Modeling Streamflows and Flood Delineation of the 2004 Flood Disaster, Mānoa, O‘ahu, Hawai‘i
Aly I. El-Kadi and Eric Yamashita, 235-255
In October 2004 a flood caused extensive damage to the University of Hawai‘i (UH) campus and neighboring residential areas in Mānoa Valley, O‘ahu, Hawai‘i. This modeling study was aimed at streamflow evaluation and flood delineation for the area impacted by the flood. The study concluded that the HEC-1 model of the U.S. Army Corps of Engineers is suitable for simulating storm runoff response for the study area, considering the nature of small Hawai‘i watersheds, which generate hydrographs with steep rising and falling limbs. The curve-number method of the U.S. Soil Conservation Service is also suitable because it predicts reasonably well the main features of streamflow hydrographs, including runoff duration and time of peaks. To improve on accuracy, however, there is a need for better characterization of spatial rainfall distribution through measurements. A flood delineation model, which treats the flood as a hypothetical dam break, was used to predict the floodwater pathway, flood zone extent, maximum flood depth, and the time to reach that depth. The model predicted an upper value for storm total flow volume that would not cause flooding on the UH campus. Although not fully validated, the developed models can guide data-collection and decision-making processes. For example, the models demonstrated that it is possible to mitigate the flood through streamflow diversion and stream dredging, realignment, and lining. For efficient management, we recommend defining a new subwatershed of the Ala Wai basin (to be called the West Mānoa Watershed) that contains the university campus.
Endemic Land Snail Fauna (Mollusca) on a Remote Peninsula in the Ogasawara Archipelago, Northwestern Pacific
Satoshi Chiba, Angus Davison, and Hideaki Mori, 257-265
Historically, the Ogasawara Archipelago harbored more than 90 native land snail species, 90% of which were endemic. Unfortunately, about 40% of the species have already gone extinct across the entire archipelago. On Hahajima, the second-largest island and the one on which the greatest number of species was recorded, more than 50% of species are thought to have been lost. We report here the results of a recent survey of the snails of a remote peninsula, Higashizaki, on the eastern coast of Hahajima. Although the peninsula is small (∼0.3 km²) and only part is covered by forest (<0.1 km²), we found 12 land snail species, all of which are endemic to Ogasawara. Among these species, five had been thought to already be extinct on Hahajima, including Ogasawarana yoshiwarana and Hirasea acutissima. Of the former, there has been no record since its original description in 1902. Except for the much larger island of Anijima and the main part of Hahajima, no single region on the Ogasawara Archipelago maintains as great a number of native land snail species. It is probable that the land snail fauna of the Higashizaki Peninsula is exceptionally well preserved because of a lack of anthropogenic disturbance and introduced species. In some circumstances, even an extremely small area can be an important and effective refuge for threatened land snail faunas.
Odonata of Yap, Western Caroline Islands, Micronesia
Donald W. Buden and Dennis R. Paulson, 267-277
Fifteen species of Odonata are recorded from Yap, Micronesia—two Zygoptera and 13 Anisoptera. None is endemic to Yap. Hemicordulia lulico occurs elsewhere only in Palau, whereas most of the other species are widespread in the western Pacific and Indo-Australian regions. Macrodiplax cora and Tramea loewi, both recorded by Lieftinck in 1962, were the only species not encountered during this study; Tramea loewi remains known in Micronesia only from a single male collected in Yap by R. J. Goss in 1950. Six of the breeding species in Yap that are widespread in Indo-Australia occur no farther east in the Caroline Islands except possibly as unusual extralimital records in the cases of Agriocnemis femina and Neurothemis terminata; the four other species reaching only as far east as Yap are Anaciaeschna jaspidea, Agrionoptera insignis, Orthetrum serapia, and Rhyothemis phyllis. Orthetrum serapia is reported from Micronesia for the first time, although a very old single specimen record of O. sabina from Tobi Island may possibly pertain to O. serapia. The odonate fauna of the outer islands of Yap State is poorly known; only six species have been recorded from among four of the 15 island groups. In addition, Tramea transmarina euryale rather than T. t. propinqua was found to be the subspecies occurring in the Chuuk Islands, contrary to earlier publications.
A New Species of Cophixalus (Anura: Microhylidae) from Misima Island, Papua New Guinea
Stephen J. Richards and Paul M. Oliver, 279-287
Cophixalus misimae Richards & Oliver, n. sp., is described from low-altitude rain forest on Misima Island, Louisiade Archipelago, Papua New Guinea. It is a small (males 15.5–16.1 mm, females 19.3–19.6 mm) terrestrial species with a visible tympanum, a snout that is distinctly truncate in dorsal view, unwebbed toes, a dark brown lateral stripe, and a call consisting of a train of high-pitched pulses. It is the third species of Cophixalus known from the Louisiade Archipelago and is currently known only from Misima Island.
First Record of Vegetative Cells of Pyrodinium bahamense (Gonyalucales: Goniodomataceae) in the Gulf of California
Aída Martínez-López, Ana E. Ulloa-Pérez, and Diana C. Escobedo-Urías, 289-1293
As part of an ongoing monitoring study of phytoplankton in coastal lagoons on the east side of the Gulf of California, Pyrodinium bahamense Plate, 1906 var. bahamense was collected in the Topolobampo–Santa Maria–Ohuira coastal lagoon system in the Gulf of California in May 2005. Average concentrations of P. bahamense were 100 cells liter-1. This finding is the first observation of vegetative cells of this tropical species in the Gulf of California and represents its northernmost occurrence to date.
Metopograpsus oceanicus (Crustacea: Brachyura) in Hawai‘i and Guam: Another Recent Invasive?
Gustav Paulay, 295-300
The grapsid crab Metopograpsus oceanicus (Jacquinot, 1852) is recorded from the Hawaiian Islands for the first time; it appears to be established at least in Kāne‘ohe Bay on O‘ahu. I review the ecology of the species in Oceania and argue that it was introduced both to the Hawaiian Islands and Guam, likely by shipping traffic. A brief review of Metopograpsus in the Hawaiian Islands is also presented.
Association Affairs, 301
Pacific Science 61, no. 3
Biology and Impacts of Pacific Island Invasive Species. 2. Boiga irregularis, the Brown Tree Snake (Reptilia: Colubridae)
Gordon H. Rodda and Julie A. Savidge, 307-324
The Brown Tree Snake, Boiga irregularis (Merrem, 1802), was accidentally transported to the island of Guam shortly after World War II. Over the following two decades it spread throughout the island with little public or professional recognition of its extent or impacts. This secretive nocturnal arboreal snake occurs in all habitats on Guam, from grasslands to forests. Under the right conditions, it is capable of high rates of reproduction and population growth. The Brown Tree Snake caused the extirpation of 13 of Guam’s 22 native breeding birds and contributed to the extirpation of several species of native bats and lizards. Guam’s 12 forest birds were especially impacted, with 10 species eliminated and the other two severely reduced. In addition, the snake continues to substantially impact domestic poultry, pets, the island’s electrical power infrastructure, and human health. To protect other vulnerable Pacific islands, the U.S. government annually spends several million dollars inspecting cargo outbound from Guam to exclude Brown Tree Snakes. Cargo destinations most at risk are in Micronesia, especially the Northern Mariana Islands, but Guam also has direct air transportation links to Hawai‘i that will soon be supplemented with direct ship traffic. Ultimately, all Pacific islands are at risk but especially those obtaining cargo through Guam.
Human Impacts on the Nearshore Environment: An Archaeological Case Study from Kaua‘i, Hawaiian Islands
Alex E. Morrison and Terry L. Hunt, 325-345
Archaeology provides a long-term framework to document prehistoric resource use and habitat modification. Excavation at Nu‘alolo Kai, Kaua‘i, yielded a large, well-preserved shellfish assemblage. Analysis determined the susceptibility of mollusk communities to human foraging pressures in the past. Some coral reef and intertidal species, such as Turbo sandwicensis and Strombus maculatus, declined in abundance as a result of heavy exploitation. In contrast, shoreline mollusk communities remained fairly stable through time. Archaeological research provides baselines for modern conservation efforts and fisheries management.
Soil Phosphorus and Agricultural Development in the Leeward Kohala Field System, Island of Hawai‘i
Molly Meyer, Thegn N. Ladefoged, and P. M. Vitousek, 347-353
The leeward Kohala Field System on the island of Hawai‘i was one of the most intensive pre–European contact dryland agricultural systems. Archaeological and soil analysis has documented changes in soil nutrients over time. Soils were collected under agricultural field walls of different relative ages within the Kohala Field System. These field walls preserved soil from the time of their construction (between ca. A.D. 1400 and 1800), so soil samples from underneath older field walls have been exposed to a shorter period of cultivation than the soils under more recent field walls. Total P and P : Nb ratios of these buried soils were greater under walls than in once-cultivated surface soils, and greater under older walls than under younger walls. These results suggest that precontact cultivation decreased soil P reserves in this intensive agricultural landscape.
Coral (Anthozoa: Scleractinia) Recruitment at Bahías de Huatulco, Western México: Implications for Coral Community Structure and Dynamics
R. A. López-Pérez, M. G. Mora-Pérez, and G. E. Leyte-Morales, 355-369
Over the past decades there has been an increasing awareness of community structure and dynamics in eastern Pacific coral reef systems, yet the processes producing these patterns are poorly known. We conducted a quantitative analysis of patterns of sexual and asexual recruitment through fragmentation at six localities in Huatulco, México. Between January 2001 and January 2002, sexual recruitment was evaluated by using terracotta tiles. Fragmentation was addressed twice using quadrats. Two hundred ninety-two corals (291 Porites panamensis Verrill, 1 Pocillopora sp.) were recruited to the settlement tiles. Changes in abundance of recruits among sites were determined by coral cover of P. panamensis at each area. Fragmentation was restricted to Pocillopora spp., and processes producing fragments had no connection with those promoting their reattachment and survival. Sexual and asexual recruitment patterns and potential survival asymmetries displayed by P. panamensis and Pocillopora spp. in the area are of capital importance in the occurrence of local communities and potentially of those of the entire eastern Pacific region. Sexual and asexual recruitment patterns suggest that recovery of frame-building corals following disturbance is highly species-specific. Recovery of P. panamensis following coral removal can be relatively fast, but greatly prolonged for Pocillopora; however, in communities with low to moderate disturbance where patches of Pocillopora were preserved reef recovery can proceed at a moderate to relatively fast pace following disturbance. Coordinated multidisciplinary and interinstitutional efforts, including genetic, histological, and ecological approaches, are necessary to determine unequivocally the processes controlling community structure and dynamics in the area.
Linckia multifora (Echinodermata: Asteroidea) in Rarotonga, Cook Islands: Reproductive Mechanisms and Ecophenotypes
Terry J. Crawford and Bruce J. Crawford, 371-381
In Rarotonga, Linckia multifora (Lamarck) exists in two forms: a blue gray type that is found on the reef intertidally and a red form that is found subtidally. Both types reproduce asexually by regeneration of autotomized arms, as well as sexually, but the relative potential for sexual reproduction varies greatly between these different sites. In the laboratory, reciprocal crosses of the blue gray intertidal form and the red subtidal form developed as successfully as the controls and were indistinguishable in morphology. In addition, both the blue gray intertidal form and the red subtidal form contain two different classes of haplotypes of the mitochondrial gene cytochrome oxidase subunit I (COI), which exhibit 12 fixed differences. These results suggest that L. multifora of Rarotonga has a dual origin and that the two different forms seen in the two environments belong to a single interbreeding population and may represent ecophenotypes.
Estimating Abundance of Reef-Dwelling Sharks: A Case Study of the Epaulette Shark, Hemiscyllium ocellatum (Elasmobranchii: Hemiscyllidae)
M. R. Heupel and M. B. Bennett, 383-394
Benthic reef sharks play an important role in reef ecosystems, but little is known about their abundance or population dynamics. Abundance of the epaulette shark, Hemiscyllium ocellatum (Bonnaterre), on Heron Island Reef, Great Barrier Reef, Australia, was examined via a mark-recapture study. A total of 496 sharks was tagged between July 1994 and August 1997 in a 0.25-km² area of reef flat, with 80 tagged sharks recaptured for a total of 102 recapture events. Captured individuals ranged in size from juveniles to adults (285–750 mm total length). Recaptured sharks were collected after 1–725 days at liberty and at distances of 0–329 m from their original capture point. The overall recapture rate was 20.6% with an estimated 17.5% tag loss. Population size was estimated using both closed and open population models. Closed population models produced various abundance estimates, with the Chao M(th) ranked best in model performance with an estimate of 2,224 sharks and 95% confidence intervals ranging from 1,730 to 2,916. Open population models produced lower estimates, with the Jolly D model producing an estimate of 559 individuals within the study site and confidence intervals ranging from 26 to 1,092. All models produced density estimations of 0.3 to 1.2 sharks per 100 m². Based on thorough examination of model assumptions and results, open population models appear to provide the best population estimate within the study area.
A Visual Sighting and Acoustic Detections of Minke Whales, Balaenoptera acutorostrata (Cetacea: Balaenopteridae), in Nearshore Hawaiian Waters
Shannon Rankin, Tom F. Norris, Mari A. Smultea, Cornelia Oedekoven, Ann M. Zoidis, Ethan Silva, and Julie Rivers, 395-398
Minke whales, Balaenoptera acutorostrata (Lacépède), have been considered a rare species in Hawaiian waters due to limited sightings during visual and aerial surveys. However, our research suggests that they are more common than previously considered. In spring 2005, a combined visual-acoustic survey of cetaceans in Hawaiian waters resulted in the sighting of a minke whale within 22 km of Kaua‘i. Minke whale vocalizations were also detected at several other locations near Kaua‘i and O‘ahu. These 2005 reports are the first from nearshore (<50 km) Hawaiian waters despite years of previous shipboard and aerial surveys. The lack of historical sightings is likely due to misidentification or the inability to detect these animals during poor sighting conditions. We recommend that future cetacean surveys in Hawaiian waters include a passive acoustic component to increase the likelihood of detecting minke whales.
Neosabellaria vitiensis, n. sp. (Annelida: Polychaeta: Sabellariidae), from Shallow Water of Suva Harbor, Fiji
Julie H. Bailey-Brock, D. W. Kirtley, Eijiroh Nishi, and Susanne M. J. Pohler, 399-406
A new species of the genus Neosabellaria Kirtley, 1994, is described from shallow-water locations of Suva Harbor, Fiji. Neosabellaria vitiensis Bailey-Brock, Kirtley, Nishi, & Pohler, n. sp., is a gregarious sabellariid; its tubes are constructed of sand and shell debris and form small “reefs” exposed during low tides. The new species is distinguished by the structure of opercular paleae in the middle row, which are shoe-shaped with circular tips, and paleae in the outer row, which have distal lateral teeth and denticulate median plume. Detailed morphological features of the new species are described and compared with other Pacific sabellariid species, particularly with most closely related N. clandestina (Menon & Sareen, 1966). Neosabellaria vitiensis is endemic to the Fiji Islands.
A new species in the Group II complex of the gekkonid lizard genus Lepidodactylus Fitzinger is described based on recently collected material from Namoluk Atoll, Mortlock Islands, Chuuk State, Federated States of Micronesia. Lepidodactylus oligoporus Buden, n. sp., is distinguished from other members of Group II by differences in the numbers of midbody scale rows (130–134), fourth-toe scansors (15–19), interorbital scales (34–35), and precloacal/femoral pore-bearing scales (12–15) and by the lack of cloacal spurs and the presence of a moderate amount of webbing between the toes. In body size and scutellation, it most resembles L. novaeguineae Brown & Parker from New Guinea and L. pulcher Boulenger from the Admiralty Islands.
Reptiles of Satawan Atoll and the Mortlock Islands, Chuuk State, Federated States of Micronesia
Donald W. Buden, 415-428
Twenty species of reptiles are recorded from the Mortlock Islands, Chuuk, Federated States of Micronesia. The eight geckos and eight skinks together comprise 80% of the herpetofauna; amphibians are absent. Most of the species are widespread in the west-central Pacific, but the recently described gecko Lepidodactylus oligoporus is known only from the type locality on Namoluk Atoll. Hemidactylus frenatus appears to be displacing Gehyra mutilata, which is common only on Namoluk Atoll, where H. frenatus is unrecorded. Five species of skinks of the genus Emoia are sympatric on Satawan Atoll. Partial habitat segregation was observed in three morphologically very similar species of Emoia, with E. cyanura being more frequently encountered in beach strand and other open, sun-exposed areas; E. caeruleocauda in shady forest; and E. impar in sun-dappled forest patches.
First Report of Gastrointestinal Helminths from the Wokan Cannibal Frog, Lechirodus melanopyga (Amphibia: Limnodynastidae) from Papua New Guinea
Stephen R. Goldberg, Charles R. Bursey, and Fred Kraus, 429-432
The initial gastrointestinal helminth list is established for Lechriodus melanopyga (Doria) from Papua New Guinea. Examination of the digestive tracts of 16 L. melanopyga from April–May (n = 14) and October (n = 2) revealed six helminth species: Digenea: Mesocoelium monas; Nematoda: Aplectana macintoshii, Cosmocerca novaeguineae, Oswaldocruzia bakeri, Abbreviata sp. (larvae in cysts); Acanthocephala: Acanthocephalus bufonis. Cosmocerca novaeguineae was present in the greatest numbers (171) and shared the highest prevalence (88%) with Acanthocephalus bufonis. Lechriodus melanopyga represents a new host record for each of these helminths. New Guinea is a new locality record for Mesocoelium monas and Acanthocephalus bufonis.
Pacific Science 61, no. 4
In the Pacific region, the African big-headed ant, Pheidole megacephala, is now widespread in tropical areas; populations are also found at higher latitudes in Australia, New Zealand, and Japan. On most inhabited tropical islands in the Pacific, P. megacephala is well known as a household and agricultural pest. Because P. megacephala does not attack humans, this species is often not recognized as an important threat. The negative ecological impact of P. megacephala, however, may be greater than that of any other invasive ant species. In areas where it occurs at high density, few native invertebrates persist. Loss of invertebrate species that serve key functions in the natural community (e.g., important prey species) may have cascading effects leading to the subsequent loss of additional species. Pheidole megacephala tends to thrive in open, disturbed habitats with weedy vegetation that can support high densities of plant-feeding Hemiptera, which these ants tend for honeydew. Before 1900, P. megacephala was known in the Pacific region only from Aru Island (Indonesia) and Hawai‘i. By the 1930s, it was found through much of Pacific Asia, Melanesia, and Polynesia, but it was not collected in Micronesia until 1950. Currently P. megacephala is known from virtually every tropical island group in the Pacific but not from many islands within the groups, particularly uninhabited islands. Quarantine efforts might be successful in keeping P. megacephala off these islands. Because P. megacephala does not commonly dominate areas with intact natural vegetation, setting aside relatively undisturbed habitat on inhabited islands may also be effective in protecting native invertebrates from attack by this ant.
Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae), a New Semi-Slug Pest on Hawai‘i Island, and Its Potential as a Vector for Human Angiostrongyliasis
Robert G. Hollingsworth, Rachel Kaneta, James J. Sullivan, Henry S. Bishop, Yvonne Qvarnstrom, Alexandre J. da Silva, and David G. Robinson, 457-467
The semi-slug Parmarion cf. martensi Simroth, 1893, was first discovered on O‘ahu, Hawai‘i, in 1996 and then on the island of Hawai‘i in 2004. This species, which is probably native to Southeast Asia, is abundant in eastern Hawai‘i Island, reportedly displacing the Cuban slug, Veronicella cubensis (Pfeiffer, 1840), in some areas. A survey in July–August 2005 found P. cf. martensi primarily in the lower Puna area of Hawai‘i Island, with an isolated population in Kailua-Kona (western Hawai‘i Island). It is now established in commercial papaya plantations, and survey participants reported it as a pest of lettuce and papaya in home gardens. Survey respondents considered P. cf. martensi a pest also because of its tendency to climb on structures where it deposits its feces and because of its potential to transmit disease. Individuals of this species were found to carry large numbers of infective third-stage larvae of the nematode Angiostrongylus cantonensis (Chen, 1935), the causative agent of human angiostrongyliasis and the most common cause of human eosinophilic meningoencephalitis. Using a newly developed polymerase chain reaction test, 77.5% of P. cf. martensi collected at survey sites were found infected with A. cantonensis, compared with 24.3% of V. cubensis sampled from the same areas. The transmission potential of this species may be higher than that for other slugs and snails in Hawai‘i because of the high prevalence of infection, worm burdens, and its greater association with human habitations, increasing the possibility of human-mollusk interactions.
Recent Records of Alien Anurans on the Pacific Island of Guam
Michelle T. Christy, Craig S. Clark, David E. Gee II, Diane Vice, Daniel S. Vice, Mitchell P. Warner, Claudine L. Tyrrell, Gordon H. Rodda, and Julie A. Savidge, 469-483
Eight anuran species were recorded for the first time in Guam in the period May 2003–December 2005, all apparently the result of arrivals to the island since 2000. Three of the eight species (Rana guentheri, Polypedates megacephalus, and Eleutherodactylus planirostris) had well-established breeding populations by 2005. A further three (Fejervarya cf. limnocharis, Fejervarya cancrivora, and Microhyla pulchra) were recorded from a number of individuals, but it is not known whether these species have established breeding opulations. Two species (Kaloula pulchra and Eleutherodactylus coqui) appear to be incidental transportations to the island that have not established. Before 2003, five anuran species, all introductions, had been recorded from Guam. Three of these, Polypedates leucomystax, Pseudacris regilla, and Kaloula picta, were detected on Guam in incoming cargo but destroyed. Two species established: Bufo marinus was deliberately introduced and the Australian hylid Litoria fallax was probably an accidental introduction. Successful establishment of anurans on Guam has increased the risk of frog introductions to nearby islands. By providing additional food sources for the brown tree snake (Boiga irregularis), anuran introductions have increased the chance that B. irregularis might substantially increase in numbers and in turn increase the risk of the snake being accidentally transported to other islands.
Arthropod Surveys on Palmyra Atoll, Line Islands, and Insights into the Decline of the Native Tree Pisonia grandis (Nyctaginaceae)
Alex T. Handler, Daniel S. Gruner, William P. Haines, Matthew W. Lange, and Kenneth Y. Kaneshiro, 485-502
Palmyra Atoll, in the Line Islands of the equatorial Pacific, supports one of the largest remaining native stands of Pisonia grandis forest in the tropical Pacific Ocean. In 2003, we surveyed terrestrial arthropods to document extant native and introduced species richness, compare these lists with historical records, and assess potential threats to native species and ecosystem integrity. In total, 115 arthropod taxa were collected, bringing the total number of taxa recorded since 1913 to 162. Few native species were collected; most taxa were accidental introductions also recorded from the Hawaiian Islands, the presumed main source of introductions to Palmyra. The overlap with previous historical surveys in 1913 and 1948 was low (<40%), and new species continue to establish, with one species of whitefly reaching pest status between 2003 and 2005. We observed numerous dead or dying large Pisonia grandis, and the green scale Pulvinaria urbicola (Coccidae) was particularly abundant on trees of poor health. Abundant introduced ants, particularly Pheidole megacephala, tended this and other hemipterans feeding on both native and introduced plants. We hypothesize that the Pheidole-Pulvinaria facultative mutualism is causing the decline of Pisonia grandis. Because of the unique properties of Pisonia grandis forest on oceanic atolls, its importance for nesting seabirds, and its alarming global decline, immediate conservation efforts should be directed at controlling introduced Hemiptera and disrupting their mutualisms with nonnative ants on Palmyra Atoll.
Scale and Benthic Composition Effects on Biomass and Trophic Group Distribution of Reef Fishes in American Samoa
Marlowe G. Sabater and Saolotoga P. Tofaeono, 503-520
We determined spatial patterns in distribution and biomass of 163 fish species in nearshore waters around Tutuila Island, American Samoa. Visual surveys of reef fishes along 30 by 5 m belt transects were conducted using a hierarchical nested design at five spatial scales from individual transects to tens of kilometers, allowing assessment of broad geographic patterns. Benthic cover data were derived from video transect surveys to test the relationship between habitat and distributions of reef fishes. We found that fish biomass, density, and numerical abundance in American Samoa are dominated by herbivores from relatively few species in the families Acanthuridae and Scaridae. Subsets of carnivore species covaried positively with live coral, algae, and coralline algae cover. Herbivores, in contrast, covaried positively with filamentous algae and coralline algae (i.e., their foods). Biomass of fishes at different trophic categories was associated with higher abundance of food material and habitat availability. Significantly higher biomass occurred along the south shore of Tutuila and at reefs with greater exposure to wave energy, such as topographic points, despite the occurrence of lower live coral cover. Significant variations in fish biomass occurred at large spatial scales, specifically at habitat and exposure levels. Variations at these scales were apparently driven by association of the most dominant trophic group with its food source and the extent but not the quality of habitat.
Life History and Courtship Behavior of Black Perch, Embiotoca jacksoni (Teleostomi: Embiotocidae), from Southern California
Bridgette Froeschke, Larry G. Allen, and Daniel J. Pondella II, 521531
The black perch, Embiotoca jacksoni Agassiz, 1853, is a common reef fish associated with nearshore marine habitats of California, with the majority of the population occurring within the Southern California Bight. Black perch were collected throughout southern California from Santa Barbara to Carlsbad, including Santa Catalina Island, to determine their physical characteristics, growth, sex ratio, periodicity of reproduction, and length of gestation. Courtship observations were conducted using scuba along the King Harbor Breakwater in Redondo Beach, California, from January 2004 to December 2005 to verify periodicity of courting and associated reproductive behaviors. Specimens captured ranged from 75 to 220 mm standard length and from 18 to 487 g in total body weight. Seven age-classes were determined by otolith aging, with the growth rate tapering off after age-class one. Seventy percent of the individuals captured were from age-classes one to three. Growth rates did not differ between sexes. Mean monthly gonosomatic indexes for males peaked from July to November, with the highest mean occurring in October. Gestating females were found from December to May, with youngest gestating females being in age-class one. Courtship behaviors were observed within aggregations and in pairs from July to November, with males being the primary aggressors. Courtship postures occurred along the base of the reef, with pairs departing into caves for copulation. This study suggests that the black perch population within the Southern California Bight has different life history characteristics and reproductive timing than those in northern California.
Vertical Distribution of Fish Larvae and Its Relation to Water Column Structure in the Southwestern Gulf of California
L. Sánchez-Velasco, S. P. A. Jiménez-Rosenberg, and M. F. Lavín, 533-548
The seasonal evolution of vertical distribution of fish larvae and its relationship with seasonal stratification, as measured by a quantitative stability parameter, were analyzed for a region off Bahía de La Paz in the southwestern Gulf of California. Samples were obtained with an opening-closing net (505 μm) in 50-m depth strata from surface to 200-m depth in May, July, and October 2001 and February 2002. Significant differences in total larval abundance and in dominant species (mesopelagic and epipelagic) were found among strata from May to October. More larvae were found in maximum-stability strata (from 16 ± 5 to 48 ± 17 m depth) than below the pycnocline (from 100- to 150-m depth). In February, the 100-m-deep surface mixed layer had a weak pycnocline at its base, and no significant difference was found. Results show that vertical distribution of fish larvae in this area depends mainly on the seasonal evolution of the water column structure, with most fish larvae in the pycnocline, at the most stable stratum of the water column.
Shallow-Water Sea Anemones (Cnidaria: Anthozoa: Actiniaria) and Tube Anemones (Cnidaria: Anthozoa: Ceriantharia) of the Galápagos Islands
Daphne Gail Fautin, Cleveland P. Hickman Jr., Marymegan Daly, and Tina Molodtsova, 549-573
We provide the first inventory of members of orders Actiniaria (sea anemones sensu stricto) and Ceriantharia (tube anemones) from the Galápagos Islands. Based on observations and collections at 48 localities throughout the archipelago that span nearly a decade, we report on eight species of actiniarians (representing families Actiniidae, Actinostolidae, Aiptasiidae, Hormathiidae, and Isophelliidae) and two of cerianthids (in families Arachnactidae and Botrucnidiferidae). We include live photographs and diagnostic features of the animals, as well as a key and map of their occurrence in the Galápagos. Two actiniarians and one cerianthid are resolved only to genus level; of those identified to species, three of the actiniarians and one of the cerianthids have an eastern Pacific distribution, one actiniarian appears to be endemic to the Galápagos Islands, and two actiniarians are broadly distributed in the Indo-West Pacific.
Vegetative and Reproductive Variability of Dictyota crenulata (Phaeophyta: Dictyotales) along the Central and Southwestern Gulf of California, México
María del Carmen Altamirano-Cerecedo and Rafael Riosmena-Rodríguez, 575-586
Dictyota crenulata J. Agardh is widely distributed throughout the Gulf of California. Comparative analyses of morphology, anatomy, and reproductive features of this species were conducted along the central western and southwestern regions of the Gulf of California. Thalli showed geographical variations in length and apical width. No differences were observed in anatomy of vegetative thalli or relative abundance of reproductive structures. Dictyota crenulata had unilayered or multilayered medullas in the basal region and in proliferations. Most thalli presented unilayered medullas in the middle section. Our observations indicate that number of medullary layers is indeed a phenotypically plastic character, in agreement with previously published results. Variations in thallus morphology such as proliferations and length are likely the result of environmental differences, also reflected in the reproduction of D. crenulata. The southwestern region had the highest percentage of all life cycle stages (female gametophytes and sporophytes, both 22%, and vegetative thalli, 14%). Our results demonstrate morphological variability in Dictyota crenulata across its distribution in the Gulf of California.
Checklist of Pacific Operculina (Convolvulaceae), Including a New Species
G. W. Staples, 587-593
A new species of Operculina (Convolvulaceae), O. polynesica Staples, is described from the Pacific. This brings to five the number of species known from Micronesia, Melanesia, and Polynesia. A key for identification is provided, nomenclature and distributions are summarized, and a list of specimens examined is included to aid herbarium curators in naming Pacific material.
Index to Volume 61, 599