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Pacific Science 62, no. 1
Population Characteristics of the Mangrove Crab Scylla serrata (Decapoda: Portunidae) in Kosrae, Federated States of Micronesia: Effects of Harvest and Implications for Management
Kimberly M. Bonine, Eric P. Bjorkstedt, Katherine C. Ewel, and Moses Palik, 1-19
Apparent declines in abundance of mangrove crabs Scylla serrata (Forsskål, 1755) in Kosrae, Federated States of Micronesia, have prompted concern regarding long-term persistence of this important cultural and economic resource. To support development of effective management strategies, we gathered basic biological information about mangrove crabs on this island, where S. serrata is the only mangrove crab species present. In particular, we were interested in understanding movement patterns and evaluating spatial variation in population structure. Many population characteristics, including estimated life span, ontogenetic shifts in habitat use, sex-specific allometric relationships, male-biased sex ratios, and evidence for limited (<2 km) alongshore movement, are similar to those reported elsewhere in the range of the species. Therefore, insights from S. serrata populations elsewhere might usefully inform management of the species on Kosrae. Moreover, information reported in this study, for which there is no ambiguity about species identification, has broader relevance. Spatial variation in size structure of the population appears to be driven by variable harvest pressure that reflects distribution of the human population and location of emerging commercial harvest operations. Effective management of mangrove crabs is therefore likely to benefit from application of size-based or sex-based restrictions on harvest and might usefully incorporate spatially explicit strategies, such as partial or complete reserves. Development and implementation of effective management will necessarily depend on cultural as well as scientific information.
The isolated Kalaupapa region, Moloka‘i Island, Hawai‘i, offers archaeologists and ecologists a unique opportunity to study traditional Hawaiian limpet (‘opihi) (Cellana spp.) harvesting from the Proto-Historic Period (1650–1795), Early Historic Period (1795–1866), and the present day. In this study, archaeological collections, modern harvests, and field observations are used to describe a regular pattern of slightly larger mean limpet size in western shoreline harvests and an increase in average limpet size from the Proto-Historic Period to the present. Although further investigations are necessary to test alternative explanations, these results suggest (1) that shelter from ocean currents and trade winds may provide a microenvironment favorable to local limpet growth, and (2) a lessening of harvesting pressure concurrent with the massive depopulation of the study area after European contact. Future studies should focus on identifying possible ecological factors impacting average size, documenting changes in limpet size using specimens from archaeological deposits, and accounting for the impact of population change on marine resources in historic and prehistoric Hawai‘i.
Growth and Mortality of Coral Transplants (Pocillopora damicornis) along a Range of Sediment Influence in Maui, Hawai‘i
Gregory A. Piniak and Eric K. Brown, 39-55
Fragments of the lace coral Pocillopora damicornis (Linnaeus, 1758) were transplanted to four sites on the south-central coast of Maui, Hawai‘i, to examine coral growth over a range of expected sediment influence. Corals remained in situ for 11 months and were recovered seasonally for growth measurements using the buoyant weight technique. Average sediment trap accumulation rates ranged from 11 to 490 mg cm-2 day-1 and were greater at the wave-exposed reef site than at the protected harbor sites. Coral growth was highest at the donor site and was higher in the summer than in the winter. A stepwise linear regression found significant effects of sediment trap accumulation and light on growth rates, but the partial correlation coefficients suggest that these factors may be only secondary controls on growth. This study did not show a clear link between coral growth and sediment load. This result may be due, in part, to covariation of sediment load with wave exposure and the inability of trap accumulation rates to integrate all sediment effects (e.g., turbidity) that can affect coral growth.
Environmental versus Genetic Influences on Growth Rates of the Corals Pocillopora eydouxi and Porites lobata (Anthozoa: Scleractinia)
L. W. Smith, H. Wirshing, A. C. Baker, and C. Birkeland, 57-69
Reciprocal transplant experiments of the corals Pocillopora eydouxi Milne Edwards & Haime and Porites lobata Dana were carried out for an 18-month period from September 2004 to March 2006 between two back reef pools on Ofu Island, American Samoa, to test environmental versus genetic effects on skeletal growth rates. Skeletal growth of P. eydouxi showed environmental but not genetic effects, resulting in doubling of growth in Pool 300 compared with Pool 400. There were no environmental or genetic effects on skeletal growth of P. lobata. Pool 300 had more frequent and longer durations of elevated seawater temperatures than Pool 400, characteristics likely to decrease rather than increase skeletal growth. Pool 300 also had higher nutrient levels and flow velocities than Pool 400, characteristics that may increase skeletal growth. However, higher nutrient levels would be expected to increase skeletal growth in both species, but there was no difference between the pools in P. lobata growth. P. eydouxi is much more common in high-energy environments than P. lobata; thus the higher flow velocities in Pool 300 than in Pool 400 may have positively affected skeletal growth of P. eydouxi while not having a detectable effect on P. lobata. The greater skeletal growth of P. eydouxi in Pool 300 occurred despite the presence of clade D zooxanthellae in several source colonies in Pool 300, a genotype known to result in greater heat resistance but slower skeletal growth. Increased skeletal growth rates in higher water motion may provide P. eydouxi a competitive advantage in shallow, high-energy environments where competition for space is intense.
Life Cycle of Chrysaora fuscescens (Cnidaria: Scyphozoa) and a Key to Sympatric Ephyrae
Chad L. Widmer, 71-82
The life cycle of the Northeast Pacific sea nettle, Chrysaora fuscescens Brandt, 1835, is described from gametes to the juvenile medusa stage. In vitro techniques were used to fertilize eggs from field-collected medusae. Ciliated planula larvae swam, settled, and metamorphosed into scyphistomae. Scyphistomae reproduced asexually through podocysts and produced ephyrae by undergoing strobilation. The benthic life history stages of C. fuscescens are compared with benthic life stages of two sympatric species, and a key to sympatric scyphomedusa ephyrae is included. All observations were based on specimens maintained at the Monterey Bay Aquarium jelly laboratory, Monterey, California.
A Review of the Octocorallia (Cnidaria: Anthozoa) from Hawai‘i and Adjacent Seamounts: The Genus Narella Gray, 1870
Stephen D. Cairns and Frederick M. Bayer, 83-115
The nine Hawaiian species of Narella are revised, including the description of six new species. All species but one (N. ornata) are described and illustrated using SEM; all species are keyed and included in a detailed table of comparison. A brief history of octocoral taxonomic research in the Hawaiian Islands is presented, resulting in a total of 90 named species for this region, only five of which occur in shallow water. Specimens were collected from throughout the archipelago and adjacent seamounts, including Cross, Pensacola, Bishop, and Bushnell, from depths of 326 to 1,977 m.
Patterns of Nestedness in Remote Polynesian Ant Faunas (Hymenoptera: Formicidae)
Lloyd W. Morrison, 117-127
The entire ant faunas of remote Polynesian islands consist of introduced species. An important question concerning the assembly of Pacific island ant faunas is whether these species are a random assortment of the available species pool, or whether they exhibit highly ordered occurrence patterns (i.e., nested subsets of species). I evaluated nestedness for the ant faunas of two island groups in remote Polynesia: (1) the Hawaiian Islands, and (2) French Polynesia and the Cook Islands. Wilcoxon two-sample tests were used to analyze nestedness patterns for individual species and islands; the degree of nestedness for species assemblages and archipelagos was determined by combining tail probabilities of individual species and islands. Both island groups revealed highly significant nestedness at the level of the assemblage (a per-species approach) as well as the archipelago (a per-island approach). Considered individually, most species (73–95%) and most islands (89–100%) demonstrated significant nestedness. Instances of nonsignificant nestedness were frequently associated with low statistical power. These results reveal a strong deterministic element in the assemblage of remote Polynesian ant faunas. Dispersal opportunities along with presence of appropriate habitat type are likely the most important mechanisms underlying the observed patterns.
Characteristics of the Psidium cattleianum (Myrtaceae) Seed Bank in Hawaiian Lowland Wet Forests
Amanda L. Uowolo and Julie S. Denslow, 129-135
Psidium cattleianum Sabine (strawberry guava) is one of Hawai‘i’s most disruptive alien plants. Dense stands can suppress growth and establishment of native species, support high populations of crop-damaging fruit flies, and preclude restoration or management of native forests. Our research investigated factors affecting persistence of P. cattleianum seeds in lowland wet forest soils. We collected soil cores from four forested sites immediately after fruit fall and 6.5 months later. We found abundant germination of P. cattleianum seeds immediately after fruit drop. Soil collected under mature P. cattleianum clumps yielded 761 viable seeds/m2. We found no viable seeds 6.5 months after fruit drop. We evaluated seed longevity using seed bags buried below the litter layer that we retrieved after 28, 56, 196, and 365 days. Seeds either germinated or deteriorated rapidly after fruit drop; after 28 days, 22.3% of the buried seeds were viable and there were no viable seeds at 196 days. Predator effects were assessed using trays with a known number of seeds with and without predator exclosures. After 28 days, 37% of the seeds in the open trays were damaged by predators. The lack of a persistent seed bank likely is due to a combination of rapid, high germination rates, postdispersal seed predation, and seed mortality. We suggest that chemical or mechanical control efforts would be most efficient and effective if conducted at least 3 months after the fruiting season, when the vast majority of seeds have either germinated or died.
Subfossil Land Snail Fauna (Mollusca) of Central Chichijima, Ogasawara Islands, with Description of a New Species
Satoshi Chiba, Tetsuro Sasaki, Hajime Suzuki, and Kazuo Horikoshi, 137-145
The fossil record provides useful information to estimate what island communities were like before human colonization. We examined the species composition of the subfossil land snail fauna of dune deposits at the Yatsuse River, central Chichijima, Ogasawara Islands, and compared it with the species recorded in Chichijima since the nineteenth century. The 22 species in the dune deposits included 13 species that are now extinct in Chichijima. Live specimens of 11 of these extinct species were recorded in the early twentieth century, but no living Mandarna pallasiana and Ogasawarana obtusa Chiba et al., n. sp., have ever been recorded. Age of the sediment, estimated by radiocarbon (14C) dating, was 720 years B.P., and it is possible that these two land snail species became extinct as a result of the impact of human colonization of the island, which started in 1830. Specifically, Ogasawarana obtusa, n. sp., became extinct before the start of taxonomic studies of the land snails of Ogasawara. The sample included Hawaiia minuscula, which is generally now considered a cosmopolitan species introduced from North America. This finding suggests that Hawaiia minuscula is not alien in Ogasawara but indigenous.
First Record of Fossorial Behavior in Hawaiian Leafroller Moth Larvae, Omiodes continuatalis (Lepidoptera: Crambidae)
Cynthia King and Daniel Rubinoff, 147-150
Larvae of the endemic Hawaiian leafroller moth, Omiodes continuatalis (Wallengren), were used in controlled exposure trials on the island of Maui, Hawai‘i, in May–August 2006, to examine effects of introduced parasitoids on native Hawaiian Lepidoptera. During the trials we observed O. continuatalis larvae burrowing up to 14 cm into the soil beneath plants on which they were deployed. This discovery reflects the first record of fossorial behavior not associated with pupation in larvae of Hawaiian Omiodes and suggests how O. continuatalis, a species once listed as extinct by the U.S. Fish and Wildlife Service, may persist despite intense pressure from introduced biological control agents.
Pacific Science 62, no. 2
Biology and Impacts of Pacific Island Invasive Species. 4. Verbesina encelioides, Golden Crownbeard (Magnoliopsida: Asteraceae)
Kathleen R. Feenstra and David R. Clements, 161-176
Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray, golden crownbeard, is a sunflower-like herbaceous annual plant ranging in height from 0.3 to 1.7 m with showy yellow flowers. It is native to the southwestern United States, the Mexican Plateau, and other parts of tropical America. Its invasive characteristics include high seed production (as many as 300–350 seeds per flower and multiple flowers per plant), seed dormancy, ability to tolerate dry conditions, and possible allelopathic effects. Disturbed areas with a relatively sandy substrate within warm, arid climate zones are vulnerable to invasion by V. encelioides. Verbesina encelioides is found on all of the main Hawaiian islands except Ni‘ihau but is particularly problematic on Midway and Kure Atoll, where it may threaten the habitat of nesting birds such as Laysan and black-footed albatrosses and Christmas and wedge-tailed shearwaters. Many other Pacific islands with similar habitats could be invaded by V. encelioides. The plant has become naturalized in many other U.S. states, parts of South America, the Bahamas, Cuba, the Dominican Republic, Puerto Rico, parts of Europe, Saudi Arabia, India, Ethiopia, Morocco, Botswana, Namibia, Israel, and Australia. It is a pest of various crops in the southern United States and India and is poisonous to sheep and cattle. Verbesina encelioides can be controlled via herbicides or mechanical means, but measures must be repeated due to the presence of persistent seed banks. Further research on V. encelioides is needed to understand its population dynamics, allelopathic properties, and impacts on natural ecosystems.
Exploiting Macrofauna Diadromy for Assessing Anthropogenic Impact in American Samoa Streams
L. M. Wade, F. S. Fanolua, A. M. Vargo, K. van Houte-Howes, E. Bardi, and D. L. Vargo, 177-190
Stream biomonitoring is increasingly used to identify and monitor changes in water quality, stream habitat, and even the surrounding watershed. An effective biomonitoring protocol must comprise attributes able to discriminate human-caused changes from natural variation. We attempted to identify such attributes for streams of American Samoa, which, in turn, might also have widespread applicability to other oceanic islands. Owing to the diadromous nature of the macrofauna, we assessed species richness, diversity, composition, dominance, and biomass of freshwater fishes, crustaceans, and mollusks in 50 m sections in midreaches of five streams with and five streams without anthropogenic influences at the estuarine reach. We electrofished for fishes and crustaceans, and we picked mollusks from stream substrates. We discovered that two species of neritid snails of the pan-Pacific genus Clithon were significantly more abundant in the midreach of streams undisturbed by human impacts at the estuarine reach, making them potentially useful bioindicators throughout the South Pacific.
Life History of the Red Spiny Lobster, Panulirus penicillatus (Decapoda: Palinuridae), in the Galápagos Marine Reserve, Ecuador
Alex Hearn and Juan Carlos Murillo, 191-204
The red spiny lobster, Panulirus penicillatus (Olivier, 1791), is exploited commercially in the Galápagos Marine Reserve by the local fishing sector. Catches and catch per unit effort have declined over the past few years, leading to concerns about sustainability of the fishery. This study supports the processes regarding the fishery management of P. penicillatus by determining its distribution and growth parameters. Nearly 3,000 lobsters were tagged during surveys carried out at 13 islands between 2000 and 2004. Sex ratio did not differ significantly from 1:1, and tagging returns showed little or no movement of individuals. Mean values with 95% confidence intervals for von Bertalanffy growth parameters were estimated to be K=0.201±0.004, L∞=16.91±0.183 (cm carapace length), and Ф’=4.14±0.019 for males; and K=0.264±0.02, L∞=12.34±0.40 (cm carapace length), and Ф’=4.99±0.06 for females. Natural mortality was 0.342 for males and 0.378 for females. These results, together with comparative estimates for red spiny lobster elsewhere, illustrate the geographical variability of growth among populations of P. penicillatus, which may occur within the archipelago itself.
A Comparison of Immature Green Turtles (Chelonia mydas) Diets among Seven Sites in the Main Hawaiian Islands
Karen E. Arthur and George H. Balazs, 205-217
Understanding resource acquisition and feeding ecology of threatened species is integral to their conservation because diet is intimately linked with growth rate and reproductive output. We examined diets of immature green sea turtles, Chelonia mydas (L.), from seven sites on the islands of Hawai‘i, O‘ahu, Moloka‘i, and Lāna‘i in January and August 2003. Diet analysis was based on 191 samples collected from 181 live green turtles by stomach lavage. These samples were identified and quantified using dissection microscopy and the principles of microstereology. Diet of green turtles in the Main Hawaiian Islands was dominated by red algae, and diet items most commonly encountered were Acanthophora spicifera (an introduced species), Hypnea sp., Pterocladiella sp., and Cladophora sp. Sea grasses (Halophila hawaiiana and H. decipiens) were an important component of diet in turtles from Kāne‘ohe Bay. Content of green turtle diets differed among foraging grounds, and these differences may provide an insight into previously documented differences in turtle growth rates among sites.
Evolutionary Lineages in Emballonura and Mosia Bats (Mammalia: Microchiroptera) from the Southwestern Pacific
D. J. Colgan and S. Soheili, 219-232
The microchiropteran bat family Emballonuridae is widely distributed in archipelagos of the southwestern Pacific, with especially strong representation of genera Emballonura and Mosia. DNA sequences from three segments of the mitochondrial genome were collected from four species of Emballonura and from M. nigrescens to investigate the relationship of genetic differentiation to archipelago biogeography. Specimens of each species formed monophyletic clades in maximum parsimony and Bayesian analyses. Mosia nigrescens was genetically distant to the other four species. The other four studied species formed a monophyletic clade composed of the pairs E. beccarii, E. serii and E. raffrayana, E. semicaudata. Clades within species were strongly concordant with geography, with only two counterexamples (E. semicaudata in Fiji and E. raffrayana in the Solomon Islands) to the general finding that each island’s population of a species constitutes a monophyletic clade. Genetic results do not agree with current subspecific designations within M. nigrescens. Samples from Woodlark, Alcester, and Manus Islands are phylogenetically closer to Papuan mainland samples than to Solomon Islands and New Ireland samples supposedly belonging to the same subspecies. Results suggest that Emballonura can establish populations across wide water barriers but does so infrequently. The isolating effect of water barriers is exemplified by the substantial genetic distinctiveness of Solomon Islands and New Ireland populations of both E. raffrayana and M. nigrescens. Absence from New Britain of E. beccarii, E. raffrayana, and E. serii (all known from New Ireland) may also reflect effects of water barriers if not due to collecting artifacts.
Relative Abundance and Distribution of Mariana Swiftlets (Aves: Apodidae) in the Northern Mariana Islands
Justine B. Cruz, Shelly R. Kremer, Gayle Martin, Laura L. Williams, and Vicente A. Camacho, 233-246
The endangered Mariana Swiftlet, Aerodramus bartschi (Mearns, 1909), occurs in its native habitat on only three islands worldwide—Guam, Saipan, and Aguiguan. It is locally extinct on the islands of Rota and Tinian, and numbers have declined on Guam. On Saipan and Aguiguan, the bird remains common. We present previously unpublished data from reports lodged with the Commonwealth of the Northern Mariana Islands Division of Fish and Wildlife combined with an analysis of arrival count data from surveys conducted regularly on Saipan (1985–2005) and opportunistically on Aguiguan (1985–2002). Direct counts of swiftlets arriving at nesting caves did not permit islandwide population estimates but provided an index useful for assessing relative abundance. On Aguiguan, swiftlets occurred in only a few of the available caves; the population was small, more densely concentrated than on the other islands, and relatively stable. On Saipan, swiftlet numbers declined for the first part of the monitoring period (1985–1992), then increased significantly (1998–2005), and now stand at their highest level (>5,000 birds) since 1985. Large between-year fluctuations, high variation in colony attendance patterns, and occasional abandonment and recolonization of some caves were evident during the 20-yr monitoring period. Of the potential constraints to the population, pesticide use, typhoons and supertyphoons, habitat alteration by feral animals, human disturbance in the nesting caves, and predation remain areas of concern. Conservation measures may have lessened some disturbance events and nest damage by cockroaches, while other measures, such as translocation, may improve the species’ chances of persistence.
A New Small-Bodied Species of Bavayia (Reptilia: Squamata: Diplodactylidae) from Southeastern New Caledonia
Aaron M. Bauer, Todd R. Jackman, Ross A. Sadlier, Glenn Shea, and Anthony H. Whitaker, 247-256
A new species of diplodactylid genus Bavayia, B. goroensis, is described from the Plaine des Lacs region of the Province Sud, New Caledonia. The new gecko is the smallest member of the Bavayia cyclura clade (49 mm snout-vent length) and, based on a molecular phylogeny, is basal within this group. It differs from other members of this group in its much smaller size, more gracile body, and lower number of precloacal pores and subdigital lamellae. The new species is known from only two locations, one of which is adjacent to extensive nickel mining operations. Because of its limited distribution and the direct and indirect threats posed by the proximity of mining to one of the populations, the species is here regarded as “Endangered.”
Role of Pro-Thrombolites in the Geomorphology of a Coastal Lagoon
D. A. Siqueiros-Beltrones, 257-269
Thrombolites are lithified biosedimentary structures generated by entrapment, precipitation, and binding of sediments promoted by growth and metabolic activity of cyanobacteria. Beaches of the coastal lagoon known as Ensenada de La Paz in Baja California Sur, México, are bordered by sedimentary formations of cyanobacterial origin identified as pro-thrombolites (incipient thrombolites) that represent a first record for the region and México. Observed thrombolithic structures show grains of varied sizes embedded within a fine-grain micritic matrix, which may be surrounded by medium-grain cementing micrite. Different degrees of consolidation occur—some crumble easily, whereas others require some manual force to break. These pro-thrombolites consist of platforms >20 cm thick and/or fragments of assorted sizes and forms. In some cases the structures have lithified, forming rocky plates (thrombolites). The extension and wide distribution of pro-thrombolites around the La Paz lagoon suggests that these structures could have determined its evolution from an original (primitive) cove into a lagoon. That is, the formation of pro-thrombolites through the entrapment and binding of sediments may have eventually altered water circulation, promoting sand sedimentation causing the formation of the El Mogote sand bar. Likewise, pro-thrombolites may have formed large extensions of headlands through accretion. Thus, several square kilometers of populated land around the La Paz lagoon may have thrombolithic origin.
Additional Marine Benthic Algae from Howland and Baker Islands, Central Pacific
Roy T. Tsuda, Peter S. Vroom, Isabella A. Abbott, Jack R. Fisher, and Kevin B. Foster, 271-290
Marine benthic algae from Howland Island and Baker Island were identified from collections made during earlier expeditions in 1924, 1935, and 1964, and during five separate expeditions between 1998 and 2004. Eighty-nine (six blue-green algae, 53 red algae, five brown algae, and 25 green algae) of the 99 species represent new records for the two islands. Forty-seven and 86 species are documented with voucher specimens from Howland Island and Baker Island, respectively. This study increases the total number of benthic marine algal species from the two islands to 104 species. A similar number (107 species) was previously reported from the nearby low coral islands in the Phoenix Group located 400 km to the southwest. Only 38% (39 of 104 species) of the algal species from Howland Island and Baker Island are reported from the Phoenix Group. The presence of Udotea palmetta Decaisne on Baker Island is of interest because the record is the first for this green algal genus in the central Pacific region.
Association Affairs, 291
Pacific Science 62, no. 3: Tropical Island Ecosystems and Sustainable Development Symposium
Biodiversity Research on Coral Reef and Island Ecosystems: Scientific Cooperation in the Pacific Region
Makoto Tsuchiya, René Galzin, and Neil Davies, 299-301
Pacific Island Forests: Successionally Impoverished and Now Threatened to Be Overgrown by Aliens?
Dieter Mueller-Dombois, 303-308
Indigenous forests in remote islands are generally impoverished of secondary successional tree species. After canopy disturbances, the same indigenous tree species seem to resume dominance by a process known as “autosuccession” or “direct succession.” Primary forest tree species are mostly colonizer species. Mature island forests are difficult to categorize as either pioneer, successional, or climax forests by their canopy species composition. Climax forests, which characterize mature forests in less-isolated areas, are typically of distinctly different canopy species composition than the pioneer forests. In central Canada, for example, pioneer pine forests are replaced in succession by mixed hardwood/softwood forests under exclusion of fire. This process is known as “normal replacement succession” or “obligatory succession.” Another well-known ecological concept distinguishes between “primary” and “secondary” forests in the continental tropics. Secondary forests are formed by fast-growing relatively short-lived second-growth species, which quickly assemble after major disturbances. It usually takes a long time for primary tropical rain forest trees to reappear in secondary forests. In contrast, primary island forests rarely include fast-growing indigenous canopy species that form such secondary forests in the continental tropics. Instead, secondary forests in islands are now made up mostly of introduced species. In this paper I attempt to evaluate alien plant invasion in remote islands in view of these concepts of ecological succession.
Differences in Associated Crustacean Fauna and Seasonality of Sexual Reproduction between Two Color Morphs of the Photosymbiotic Ascidian Didemnum molle (Ascidiacea: Didemnidae)
Takumi Fukuda and Euichi Hirose, 309-316
Photosymbiotic ascidians inhabiting subtropical waters tend to have gonads in spring and summer, whereas those in tropical waters are usually sexually mature year-round. We studied the seasonality of sexual reproduction in two populations of the photosymbiotic ascidian Didemnum molle (Herdman, 1886), sampling monthly for 12 months. Although the two populations were located only about 20 km apart, their color morphs were exclusively distributed: colonies of one population were always dark gray; those of the other population were mostly brown. The seasonality of sexual reproduction differed greatly between the populations (and thus between the color morphs). Sexual reproduction was limited to summer in the population with dark gray colonies, whereas the population with brown colonies possessed embryos with tails almost year-round. Moreover, the resident crustacean fauna in the colonies also differed between the populations. The microenvironment in each habitat may have caused these differences, but there may also be some physiological differences between the color morphs that affect the seasonality of sexual reproduction and the resident crustacean fauna.
Distribution and Possible Impacts of Toxic Organic Pollutants on Coral Reef Ecosystems around Okinawa Island, Japan
S. T. Imo, M. A. Sheikh, K. Sawano, H. Fujimura, and T. Oomori, 317-326
Organic pollutants have detrimental effects on the environment. In this study we evaluated the current status of contamination with organochlorine pesticides (OCPs), organo-tin compounds (OTCs), and polychlorinated biphenyls (PCBs) in the waters in and around Okinawa Island, Japan. Possible toxicological effects of these pollutants on marine life including corals are also discussed. Concentrations of total OCPs in river water were in the range of 1.02–56.4 ng liter-1. Among the OCPs, α-BHC, β-BHC, and aldrin were common in river water. OTCs detected in 30 samples of seawater were (mean ± SD) monobutyl tin (MBT), 0.44 ± 0.75 ng (Sn) liter-1; dibutyl tin (DBT), 1.32 ± 2.70 ng (Sn) liter-1; tributyl tin (TBT), 0.72 ± 2.90 ng (Sn) liter-1; monophenyl tin (MPhT), 0.04 ± 0.42 ng (Sn) liter-1; diphenyl tin (DPhT), 0.007 ng (Sn) liter-1; and triphenyl tin (TPhT), 0.013 ng (Sn) liter-1. Highest concentrations of TBT, 28.5 ng (Sn) liter-1 for water and 172 ng (Sn) g-1 dry weight for sediment, were detected in samples from Itoman Port. Concentrations of total PCBs were 0.05–0.28 ng liter-1 in open ocean and from 1.59 to 2.48 ng liter-1 in coastal waters. Overall, this study shows that the coral reef ecosystems and their adjacent environments around Okinawa Island are contaminated by toxic organic contaminants (OCPs, OTCs, and PCBs). Levels of these contaminants detected in some sites have exceeded the Environmental Quality Target (EQT), which may pose a risk to health of marine life.
Reproductive Biology and Early Development of Two Species of Sleeper, Eleotris acanthopoma and Eleotris fusca (Teleostei: Eleotridae)
Ken Maeda, Nozomi Yamasaki, Masashi Kondo, and Katsunori Tachihara, 327-340
Reproductive biology and early development of two species of sleepers, Eleotris acanthopoma Bleeker, 1853, and E. fusca (Forster, 1801), were investigated in streams on Okinawa Island in southern Japan. Gonadal examination and morphology of the genital papillae indicated that E. acanthopoma matured at a smaller body size (ca. 28 mm in standard length) than E. fusca (ca. 50 mm). Mature ovaries were composed of oocytes that could be categorized into two size classes. Larger females of both species had several hundred thousand developed oocytes in the larger size class and may spawn them at one or several consecutive spawning events. Egg masses of both species were found in habitats typically occupied by adults and were deposited, often sparsely, on the underside of objects. Form of the egg masses and morphology of eggs and newly hatched larvae of both species were almost identical. Eggs were a nearly spherical pyriform in shape, with the widest diameters measuring approximately 0.4 mm. Newly hatched larvae were very small (1.0–1.4 mm in notochord length) and undeveloped. The mouth opened and the eyes became pigmented 3 days after hatching, and all of their yolk was consumed 4 days after hatching. Reproductive strategies of both species were characterized by high fecundity through production of small eggs and small newly hatched larvae, with high fecundity likely to mitigate the presumed increased risk associated with widespread larval dispersal.
Flicker Light Effects on Photosynthesis of Symbiotic Algae in the Reef-Building Coral Acropora digitifera (Cnidaria: Anthozoa: Scleractinia)
Takashi Nakamura and Hideo Yamasaki, 341-350
Reef-building corals inhabit a variety of aquatic habitats with a range of light conditions. Because the coral host depends on photosynthetic products assimilated from endosymbiotic algae, reef-building corals have to cope with irradiance fluctuations on instantaneous to seasonal time scales. Underwater high-frequency light fluctuations resulting from the lens effect on the water surface are prominent in oligotrophic coral reef environments, a phenomenon known as flicker light. Effects of flicker light on endosymbiont photosynthesis of the reef-building coral Acropora digitifera (Dana, 1846) were evaluated with pulse amplitude modulation chlorophyll fluorometry. At supersaturating light intensities, photosynthesis was less inhibited by flicker light than by constant light. Reduction in photoinhibition by flicker light was pronounced at high water temperatures. Flicker light may strongly influence endosymbiont photosynthesis of corals inhabiting shallow reef habitats, especially during periods of strong solar irradiance and high water temperature.
Molecular Phylogeography of the Endemic Five-lined Skink (Plestiodon marginatus) (Reptilia: Scincidae) of the Ryukyu Archipelago, Japan, with Special Reference to the Relationship of a Northern Tokara Population
Masanao Honda, Taku Okamoto, Tsutomu Hikida, and Hidetoshi Ota, 351-362
Phylogenetic relationships were inferred for populations of the Ryukyu five-lined skink Plestiodon marginatus, a species showing an extraordinary distribution across the Tokara Tectonic Strait. Phylogenetic analyses of 809 base positions of the mitochondrial 12S and 16S rRNA genes supported collective divergence of the southern Tokara and northern Amami populations, which have been classified as P. m. oshimensis. A population from Nakanoshima, an island of the Tokara Group north of the Tokara Tectonic Strait, has the closest affinity with the Okinawajima population of P. m. marginatus rather than with the geographically closer southern Tokara and northern Amami populations. This result is concordant with that of a recent allozyme study and suggests an origin of the Nakanoshima population through long-distance dispersal from the Okinawa Island Group. Also, our results strongly suggest a closer relationship of a population of P. m. oshimensis from Okinoerabujima, a southern island of the Amami Group, with P. m. marginatus from Okinawajima than with the “consubspecific” southern Tokara and northern Amami populations. Both Nakanoshima and Okinoerabujima populations are usually referred to as P. m. oshimensis, and therefore our results indicate nonmonophyly of P. m. oshimensis in the current taxonomic arrangement.
Canopy Multilayering and Woody Species Diversity of a Subtropical Evergreen Broadleaf Forest, Okinawa Island
Akio Hagihara, S. M. Feroz, and Masatsugu Yokota, 363-376
Woody species diversity and the spatial distribution of trees in a subtropical evergreen broadleaf forest on a silicate substrate, Okinawa Island, were investigated to determine the forest’s architectural stratification. The forest stand consisted of four architectural layers. The values of Shannon’s index Hʹ and Pielou’s index Jʹ tended to increase from the top layer downward, except for the bottom layer. The lower layers contained many species relative to their smaller height ranges. High woody species diversity of the forest depended on small trees. This trend of species diversity was different from that of forest on a limestone substrate on Okinawa Island, where high woody species diversity depended on large trees. Conservation of small trees in the lower layers, especially the bottom layer, is indispensable to maintain diversity in Okinawan evergreen broadleaf forests. Castanopsis sieboldii (Mak.) Hatusima had the highest importance value in all layers, indicating that it is typically a facultative shade species as well as a climax species. The spatial distribution patterns of trees were found to be random in the lower three layers, but in the top layer clumping seemed to occur at three spatial scales. A high degree of overlapping in spatial distributions of trees among the layers suggested that light cannot penetrate easily into the lower layers. As a result, most species in the lower layers must be shade-tolerant. Mean weight index decreased from the top toward the bottom layer, and tree density increased from the top downward. This trend resembled the mean weight-density trajectory of self-thinning plant populations.
Biogeographic patterns of the Crustacea (Decapoda and Stomatopoda) are given for the tropical Pacific, based on recent taxonomic studies combined with emergence of regional databases. Conclusive results are still difficult to obtain due to incomplete regional inventories and existence of complexes of sibling species with unclear taxonomic status. A time-series graph of the number of new records plotted against time is computed for several central Pacific islands (French Polynesia, Pitcairn, Easter Island, and Clipperton). It demonstrates that the fauna is still insufficiently known in those places. A biodiversity gradient is calculated for several taxa between West and East Pacific. The traditional decrease between Australia and French Polynesia is confirmed for higher taxa (Brachyura, Anomura), but at lower taxonomic levels it is not always verified (e.g., hermit crabs, Calcinus; crabs, Trapezia). A map is presented illustrating the following provisional biogeographic results: (1) cryptic endemic species recognized in the Marquesas Islands; (2) presence of a distinct faunistic province in the South Pacific, along the 25° S parallel, including Rapa and Easter Islands; (3) theoretical position of the border between the Indo-West Pacific (IWP) and East Pacific (EP) faunistic provinces (84 W on the seamounts of Sala y Gómez/Nazca and 110° W on Clipperton); (4) differences between Clipperton, with a mixed IWP-EP fauna (43% IWP versus 57% EP species), and the Galápagos, with obvious EP affinities (10% IWP versus 90% EP species).
Genetic Relationships among Species of Meretrix (Mollusca: Veneridae) in the Western Pacific Ocean
Ayako Yashiki Yamakawa, Masashi Yamaguchi, and Hideyuki Imai, 385-394
We compared allozymes at 12 loci in 12 populations of six species of Meretrix: M. lusoria (Japan, Korea, and Taiwan), M. petechialis (China and Korea), M. ovum (Thailand and Mozambique), M. lyrata (China), M. lamarckii (Japan), and Meretrix sp. A (Okinawa, Japan). Our allozyme results were generally consistent with the major groupings currently recognized within the genus based on morphological characters. However, we found two cryptic or undescribed species: Meretrix sp. A from Okinawa and M. cf. lusoria from Taiwan. The shell characters of Meretrix sp. A were similar to those of M. lamarckii, but the species was genetically distinct (Nei’s genetic distance D > 0.845) from all other species examined. The Taiwanese Meretrix population was morphologically indistinguishable from Japanese M. lusoria, although the genetic distance between the Taiwanese and Japanese populations showed a high degree of genetic differentiation (D > 0.386). Meretrix lusoria seedlings were introduced into Taiwan from Japan in the 1920s, and Japanese M. lusoria was previously thought to be established as a cultured stock. However, our results suggest that the Taiwanese population may represent a sibling or cryptic species of M. lusoria.
Systematic Review of Late Pleistocene Turtles (Reptilia: Chelonii) from the Ryukyu Archipelago, Japan, with Special Reference to Paleogeographical Implications
Akio Takahashi, Hiroyuki Otsuka, and Hidetoshi Ota, 395-402
The Quaternary terrestrial turtle fauna of the Ryukyu Archipelago was reviewed on the basis of recently excavated fossils, as well as literature information. As a result, five extinct species (four geoemydids [Cuora sp., Geoemyda amamiensis, Mauremys sp., and another species with undetermined generic and specific status] and one testudinid [Manouria oyamai]) were recognized from Late Pleistocene cave and fissure deposits. Two of the three turtles currently occurring in this archipelago (C. flavomarginata and G. japonica) were also recognized from comparable deposits on islands, including those where they do not occur at present. These records indicate that the terrestrial turtles of the Ryukyus were much more diverse during the Late Pleistocene than at present, and that extinction has occurred during the last few tens of thousands of years not only for those five fossil species but also for some island populations of the extant species. Distributions of three of the extinct species (G. amamiensis, Cuora sp., and the geoemydid [genus and species undetermined]), confined to the central Ryukyus, are concordant with the currently prevailing hypothesis of Ryukyu paleogeography, which assumes a relatively long isolation of this region and much more recent insularization of the southern Ryukyus. In contrast, distributions of the remaining two extinct species (Man. oyamai and Mau. sp.) must be explained by some ad hoc scenario or, otherwise, drastic modification of the current hypothesis.
Low Genetic Diversity of Oval Squid, Sepioteuthis cf. lessoniana (Cephalopoda: Loliginidae), in Japanese Waters Inferred from a Mitochondrial DNA Non-coding Region
Misuzu Aoki, Hideyuki Imai, Tohru Naruse, and Yuzuru Ikeda, 403-411
Genetic diversity and population structure of Japanese populations of the oval squid, Sepioteuthis cf. lessoniana, were compared with populations from Taiwan and Vietnam using nucleotide sequences of the mitochondrial DNA non-coding region 2. In total, 402 nucleotide sequences representing 242 individuals from Japanese waters (Ishikawa, Japan Sea coast of Honshu; Tokushima, eastern Shikoku; Nagasaki, western Kyushu; and Okinawajima and Ishigakijima Island, in the Ryukyu Archipelago) and the East and South China Seas (Keelung, northern Taiwan; Vietnam, Gulf of Tonkin) were examined. Among the 29 haplotypes recognized, haplotype no. 1 was shared by more than 75% of individuals from Japanese localities, whereas it was found in less than 13% of specimens from the East and South China Seas populations. Conversely, the East and South China Seas populations included more than 30% individuals with haplotype no. 2, whereas less than 10% of haplotype no. 2 individuals were from Japanese localities. The differences of haplotype and nucleotide diversities between pooled Japanese populations (0.2639, 0.23%) and the East and South China Seas populations (0.7900, 1.01%) indicate that S. cf. lessoniana from Japanese waters exhibits lower genetic diversity. An analysis of molecular variance between the Japanese populations and the East and South China Seas populations was highly significant. A minimum spanning tree of 29 haplotypes and an Unweighted Pair Group Method with Arithmetic mean (UPGMA) tree based on pairwise FST comparisons also supported the separation between Japanese and the East and South China Seas populations. We suggest that the Kuroshio Current physically limits gene flow and has thus caused the differences in genetic diversity among the populations examined.
Dispersal distance of planktonic larvae of coral reef organisms is influenced by their ecological characteristics and environmental factors such as current flow and physical structure of reefs. This study reviews the degree and pattern of genetic differentiation in scleractinian corals in the Ryukyu Archipelago, compared with other regions. Small-scale genetic heterogeneity, but broad-scale homogeneity, was detected in some species, including brooders and spawners in the Ryukyus. Comparison with other regions indicated that limited gene flow on a small spatial scale (i.e., self-recruitment) seemed to occur in many regions. However, the degree of gene flow over larger distances was complex and species-dependent. With an implication for conservation in the Ryukyus, the larval source hypothesis, which states that coral larvae were recruited from the Kerama Islands to the Okinawa Islands, was consistent with results illustrating high gene flow in some species. Thus, conservation of corals in the Kerama Islands is high priority. Detection of genetic breaks between the southern and central Ryukyus was not common among species. The genetic structure observed in corals is highly variable and depends on both species and spatial scale in the Ryukyus. In addition, the complex genetic structures of corals may be related to coral-specific destructive events, such as bleaching, outbreaks of crown-of-thorns starfish, and disease. Further studies will provide new insights and a more detailed view of the genetic structure of corals by using different markers (e.g., microsatellites) and approaches (assignment tests and clustering analysis), which will provide useful information for coral reef conservation.
Dietary Habits of the Introduced Cane Toad, Bufo marinus (Amphibia: Bufonidae), on Ishigakijima, Southern Ryukyus, Japan
Noriko Kidera, Nontivich Tandavanitj, Daehyun Oh, Nozomi Nakanishi, Aya Satoh, Tetsuo Denda, Masako Izawa, and Hidetoshi Ota, 423-430
We examined dietary habits of the introduced cane toad Bufo marinus at three sites representing different types of habitats (pond, forest, and rice paddy) on Ishigakijima Island, southern Ryukyus, Japan. Stomach contents analysis revealed that the toad mostly utilizes terrestrial arthropods, of which hymenopterans (mostly ants), adult coleopterans, hemipterans, and araneans dominated in the frequency of occurrence, hymenopterans in the numerical proportion, and larval lepidopterans, adult coleopterans, and larval dipterans in the volumetric proportion. Comparisons in taxonomic composition of the toad’s stomach contents and pitfall and sweeping net samples suggested ignorance or avoidance of Amphipoda by the toad. Our results suggest the possibility of considerable predation pressure of B. marinus upon the native arthropods, and ants in particular, on Ishigakijima Island.
A Framework for Assessing Impacts of Marine Protected Areas in Moorea (French Polynesia)
Thierry Lison de Loma, Craig W. Osenberg, Jeffrey S. Shima, Yannick Chancerelle, Neil Davies, Andrew J. Brooks, and René Galzin, 431-441
Marine Protected Areas (MPAs) have been promoted as effective management tools to protect biodiversity at local and global scales, but there remains considerable scientific uncertainty about effects of MPAs on species abundances and biodiversity. Commonly used assessment designs typically fail to provide irrefutable evidence of positive effects. In contrast, Before-After-Control-Impact (BACI) designs potentially remedy many of these problems by explicitly dealing with both spatial and temporal variation. Here, we document the historical context of implementation and the scientific assessment of MPAs recently established at eight sites around the island of Moorea, French Polynesia. In 2004, we designed and implemented a monitoring plan that uses a BACI-Paired Series (BACIPS) design to quantify the effect of the MPAs. Twice per year, we monitor fish, corals, and other benthic invertebrates at 13 sites (eight within MPAs and five outside MPAs) around Moorea, in three distinct reef habitats (fringing, barrier reef, and outer slope). We present statistical analyses of data collected during five surveys (July 2004 to July 2006), before the initiation of enforcement. We also assessed the potential of our program to detect future responses to the established MPA network. Our estimates of biomass for five categories of fishes (Acanthuridae, Chaetodontidae, Serranidae, Scaridae, and fisheries target species) within MPA sites generally track estimates in paired Control sites through time. Estimated statistical power to detect MPA effects (a 192% biomass increase within the MPA) was high at the MPA network scale but varied among taxonomic categories and reef habitats: power was high on the reefouter slope and lower in the lagoon, and generally high for acanthurids and chaetodontids. It did not vary significantly between sites. We discuss limitations of our approach (shared by all MPA assessments to date) and describe solutions and unique opportunities to redress these limitations in French Polynesia.
Pacific Science 62, no. 4
Historical Tropical Cyclone Activity and Impacts in the Cook Islands
Fes A. de Scally, 443459
Analysis of a recently completed database of 143 tropical cyclones in the Cook Islands revealed a minimum average frequency of 0.8 cyclones per cyclone season between 1820 and 2006, with a more-precise frequency of 1.8 cyclones per season with the beginning of satellite monitoring of cyclones in 1970. Since 1970, 31% of cyclones have reached hurricane intensity. The Southern Cooks have been more than twice as frequently affected by cyclones as the Northern Cooks, with the island of Palmerston having the greatest number of encounters. Since 1820, 96% of cyclones have occurred during the official November–April cyclone season, with February alone accounting for 29%. Since 1970, 46% of cyclones achieving hurricane status have occurred in February. Nevertheless, Cyclone Martin in October–November 1997 demonstrated the dangers of a cyclone occurring outside the official season. An increase in cyclone occurrences since the mid-1970s is probably attributable to satellite monitoring, but it is noteworthy that all six cyclones known for certain to have achieved major hurricane status have occurred since 2002. Since 1970, 56% of cyclones have occurred during El Niño events, an increase of 15% from the 1870–1969 period. Since 1891, cyclones with moderate and major human impacts have occurred on average at least every 3.8 and 8.8 yr, respectively, with the Southern Cooks more than twice as frequently affected as the Northern Cooks. However, past cyclone disasters in the latter group suggest that risk to human life is greater there due to the potential for inundation of the atolls by storm surges. Half of cyclones with human impacts have occurred during El Niño events, with weak to moderate El Niños almost as important in this respect as strong El Niños. Only 13% of cyclone impacts have occurred during La Niña events.
Was Tropical Cyclone Heta or Hunting by People Responsible for Decline of the Lupe (Ducula pacifica) (Aves: Columbidae) Population on Niue during 1994–2004?
R. G. Powlesland, D. J. Butler, and I. M. Westbrooke, 461-471
On 6 January 2004, Tropical Cyclone Heta devastated much of the South Pacific island nation of Niue. The forest suffered extensive damage, particularly to the north-western sector, with many trees uprooted and others stripped of branches and foliage. Even though some patches of forest in the southeast sustained little damage, many lupe (Pacific pigeon, Ducula pacifica) and kulukulu (purple-crowned fruit dove, Ptilinopus porphyraceus) entered eastern villages in search of food and water after the cyclone, a very unusual behavior. This paper details our findings from a survey of some of Niue’s forest birds carried out during September 2004 and compares these with results from a similar survey in September 1994. Five-minute point count data, an index of conspicuousness, from three transects showed that heahea (Polynesian triller, Lalage maculosa) were more abundant in 2004 than in 1994, that the results were variable from transect to transect for miti (Polynesian starling, Aplonis tabuensis) and kulukulu, but that significantly fewer lupe were detected along all three transects in 2004 than previously. We tentatively suggest that the decline in the lupe population was caused mainly by unsustainable human hunting during 1994–2004, rather than mortality caused by the cyclone.
Determining composition and structure of ant communities may help understand how niche opportunities become available for invasive ant species and ultimately how communities are invaded. This study examined composition and structure of an ant community from a tropical rain forest in Fiji, specifically looking at spatial partitioning and presence of invasive ant species. A total of 27 species was collected, including five invasive species. Spatial partitioning between arboreal (foliage beating) and litter (quadrat) samples was evident with a relatively low species overlap and a different composition of ant genera. Composition and abundance of ants was also significantly different between litter and arboreal microhabitats at baits, but not at different bait types (oil, sugar, tuna). In terms of invasive ant species, there was no difference in number of invasive species between canopy and litter. However, the most common species, Paratrechina vaga, was significantly less abundant and less frequently collected in the canopy. In arboreal samples, invasive species were significantly smaller than endemic species, which may have provided an opportunity for invasive species to become established. However, taxonomic disharmony (missing elements in the fauna) could also play an important role in success of invasive ant species across the Pacific region. Invasive ants represent a serious threat to biodiversity in Fiji and on many other Pacific islands. A greater understanding of habitat susceptibility and mechanisms for invasion may help mitigate their impacts.
Ecology of the Endemic Land Crab Johngarthia malpilensis (Decapoda: Brachyura: Gecarcinidae), a Poorly Known Species from the Tropical Eastern Pacific
Mateo López-Victoria and Bernd Werding, 483-493
Johngarthia malpilensis (Faxon, 1893) is the least studied of the eight American species of Gecarcinidae. This land crab is considered endemic to Malpelo, an oceanic island of the Colombian Pacific. Several aspects of its ecology were investigated between 2003 and 2006. We estimated its population density, distribution, daily activity, reproduction, interactions, and diet by marking and monitoring 909 individuals. During our visits we recorded crabs of sizes from 5 to 82 mm carapace width. Johngarthia malpilensis shelters mainly in fissures and hollows between rocks. It is distributed all over the main island except in very steep sectors. An average density of 0.41 adults m-2 and 0.55 juveniles m-2 produced an estimated total population of 833,000. Johngarthia malpilensis showed high mobility, with crabs covering distances over 450 m in a few days on highly irregular surfaces. Activity was higher from dusk till dawn and lowest around noon. Release of larvae took place during the high tides associated with the new moon, at least during the rainy season. It is omnivorous and opportunistic, consuming practically every available resource. The crab is occasionally preyed upon by an endemic lizard and migratory birds. Its general ecology is very similar to that of J. planatus, a closely related species. As a voracious omnivore J. malpilensis is one of the most important components of Malpelo’s food web.
First Records of Butterflies (Lepidoptera) from the Republic of Nauru
Donald W. Buden and W. John Tennent, 495-498
Four species of butterflies are reported from Nauru for the first time and as first records of butterflies from the island republic. None is endemic. Three of the four species are widespread in Oceania: Badamia exclamationis (Fabricius), Danaeus plexippus (Linnaeus), and Hypolimnas bolina (Linnaeus). The other, Petrelaea tombugensis (Röber), belongs to a genus that also is widespread in the Pacific. The small number of widespread species found on Nauru is comparable with the situation encountered on other small, remote, low-lying Pacific islands.
The Reptiles of Nauru
Donald W. Buden, 499-507
Eleven species of reptiles are reported from Nauru in the first systematic treatment of the herpetofauna. Four of the species are marine; the seven others include six lizards (four geckos, two skinks) and one snake. Gehyra mutilata (Wiegman), G. oceanica (Lesson), Pelamis platura (Linnaeus), and Ramphotyphlops braminus (Daudin) are recorded on Nauru for the first time. With the exception of Emoia arnoensis Brown & Marshall, which is endemic to eastern Micronesia, the herpetofauna consists of species that range widely among the west-central Pacific Ocean islands. The only known record of E. arnoensis from Chuuk possibly is based on a misassigned locality, in which case the range of the species would be limited to the Marshall Islands, Nauru, and Kosrae. There is no evidence to suggest that habitat modification on Nauru stemming largely from more than a century of phosphate mining has reduced the number of reptile species.
Inventory of Thysanoptera Collected from French Polynesia
Mark S. Hoddle, Christina D. Hoddle, and Laurence A. Mound, 509-515
A survey for Thysanoptera was conducted in the Society (Tahiti, Moorea, and Raiatea), Marquesas (Hiva Oa, Nuku Hiva, Ua Huka, and Ua Pou), and Austral islands (Rurutu and Tubuai) archipelagos in French Polynesia from September 2003 to November 2005. At least 55 thrips species in 36 genera and three families were identified from 823 slide-mounted specimens that were collected from 61 host plants in 33 families. Twelve species are considered to be important pests. The greatest diversity of species, 43 (77%), was collected from the Society Islands, with 60% being recorded from Tahiti alone. Species diversity was intermediate in the Marquesas Islands at 43% (24 species collected), with 35% or 19 species being recorded from Nuku Hiva. Lowest diversity was recorded for the Austral Islands, with 38% or 21 species being found in that archipelago. Less than 10% of collected species are likely to be native, with the majority of identified thrips (>90%) in French Polynesia representing a high diversity of exotic species (leaf, flower, and fungus feeders, and four predatory species) that have successfully infiltrated other island groups in the South Pacific. Survey results and subsequent estimates of thrips species diversity in French Polynesia should be interpreted with caution due to uncontrolled variation in sampling intensity that was affected by survey duration, time of year, and visitation frequency to islands.
Attempt to control the Invasive Red Alga Acanthophora spicifera (Rhodophyta: Ceramiales), in a Hawaiian Fishpond: Assessment of Removal Techniques and Management Options
Mariska Weijerman, Rebecca Most, Kristy Wong, and Sallie Beavers, 517-532
Acanthophora spicifera (Vahl) Børgesen was unintentionally introduced to Hawai‘i in 1950 and has since become the most common nonindigenous algal species in the main Hawaiian Islands. On the west coast of Hawai‘i Island it has been documented at three sites, including Kaloko Fishpond in Kaloko-Honokōhau National Historical Park. The fishpond has an open connection to the sea, increasing the risk that A. spicifera will establish itself on neighboring shallow coral reefs and rocky intertidal habitats. To diminish that risk and to develop an efficient management strategy, a range of approaches was assessed to control this invasive alga in Kaloko Fishpond. Removal techniques were labor intensive and had limited effect. All experiments showed a substantial initial decrease in algal density, but the long-term effect was minimal because of rapid regrowth. The most promising removal method was the use of submerged shelters to raise local densities of herbivorous fishes. Fishes grazed the alga and quickly reduced the biomass. However, the large number of predators and absence of topographical structure will make it challenging to provide sufficient shelters to increase the herbivorous fish population in the entire fishpond. A management strategy to substantially reduce the algal biomass in the fishpond includes a combination of biological control and periodic manual removal of the alga.
Relationships Between Otolith Size and Body Size for Hawaiian Reef Fishes
Ken Longenecker, 533-539
Estimating body size of fishes from remains recovered from piscivores, archaeological sites, and sedimentary deposits is desirable but rarely accomplished because the relationships between the size of a fish and its durable anatomical structures are largely unknown. Regression equations to predict the size or weight of 41 common Hawaiian reef fishes from sagittae (saccular otoliths) are presented. Data are also grouped into higher taxa to permit size predictions when otoliths cannot be assigned to species.
Maximum Annually Recurring Wave Heights in Hawai‘i
Sean Vitousek and Charles H. Fletcher, 541-553
The goal of this study was to determine the maximum annually recurring wave height approaching Hawai‘i. The motivation was scientific as well as administrative: to enhance understanding of the recurring nature of dominant swell events, as well as to inform the Hawai‘i administrative process of determining the “upper reaches of the wash of the waves” (Hawai‘i Revised Statutes [H.R.S.] § 205-A), which delineates the shoreline. We tested three approaches to determine the maximum annually recurring wave, including log-normal and extremal exceedance probability models and Generalized Extreme Value (GEV) analysis using 25 yr of buoy data and long-term wave hindcasts. The annual recurring significant wave height was found to be 7.7 ± 0.28 m (25 ft ± 0.9 ft), and the top 10% and 1% wave heights during this annual swell was 9.8 ± 0.35 m (32.1 ft ± 1.15 ft) and 12.9 ± 0.47 m (42.3 ft ± 1.5 ft), respectively, for open North and Northwest Pacific swell. Directional annual wave heights were also determined by applying hindcasted swell direction to observed buoy data lacking directional information.
Demographic Parameters of Yellowfin Croaker, Umbrina roncador (Perciformes: Sciaenidae), from the Southern California Bight
Daniel J. Pondella II, John T. Froeschke, Lynne S. Wetmore, Eric Miller, Charles F. Valle, and Lea Medeiros, 555-568
The yellowfin croaker, Umbrina roncador Jordan & Gilbert, 1882, is a common nearshore and surf-zone species in the southern California bight. Age was determined for individuals (n = 1,209) using annual increments in otoliths, and size at age was modeled using the von Bertalanffy growth curve (L∞ = 307.754 mm, k = 0.278 yr-1, t0 = -0.995 yr; maximum age = 15 yr). Females (L∞ = 313.173 mm, k = 0.307 yr-1, t0 = -0.771 yr) grew significantly faster and larger than males (L∞ = 298.886, k = 0.269 yr-1, t_0 = -1.072 yr). Age and growth modeling based upon otolith length (OL) and width (OW) measurements were assessed and were consistent with body measurements. Males and females were found in all size classes and in an overall 51:49 ratio that was not significantly different from a 50% sex ratio, suggesting that these fish are gonochores. Fish were reproductive during summer months, with gonadosomatic indices (females, 5.65%; males, 5.51%) consistent with group-spawning fishes. Data from two separate monitoring programs indicated that yellowfin croaker catch-per-unit-effort (CPUE) fluctuated appreciably from 1992 to 2006 on both spatial and temporal scales. CPUE also declined significantly in the latter years of these programs. Based on samples collected between 2003 and 2004, an estimate of overall annual total mortality was A = 0.4492, and instantaneous coefficient of total mortality was estimated at Z = 0.5964. Recruitment year classes were back calculated using annual survivorship. Year class strength was variable and declined significantly by the end of this study. Considering the high temporal and spatial variation in estimates of abundance and recruitment, coupled with the likelihood that these fish employ a probable group-spawning reproductive behavior, we recommend a cautious approach for the future management of this species.
Acropora (Anthozoa: Scleractinia) Reproductive Synchrony and Spawning Phenology in the Northern Line Islands, Central Pacific, as Inferred from Size Classes of Developing Oocytes
Jean C. Kenyon, 569-578
Little is known of the timing of reproduction in central Pacific coral populations near the equator. Oocyte pigmentation and size comparison with sizes of mature eggs reported in published literature were used to infer intra- and interspecific synchrony and probable spawning phenology in 15 species of Acropora from Palmyra and Kingman atolls in the northern Line Islands. Sampling at both atolls took place in March–April 2002 and 2004. Oocyte sizes were determined from microdissections of fixed, decalcified samples. The majority (91.2%) of samples (n = 209) were gravid, with high levels of fertility in most (84.3%) samples. Statistically discrete oocyte size classes could be distinguished in most taxa at each atoll in each year. These discrete oocyte size classes suggest that several episodes of spawning, involving multiple species, take place over 2 or 3 months beginning in early spring. These data, which are the first observations of coral reproductive synchrony in the Line Islands, support the results of other recent studies, suggesting that reproductive synchrony can be a feature of equatorial reef assemblages where the annual ranges of sea-surface temperature and tidal amplitude are small.
Between October 2003 and July 2005, aggregation behavior of the sea urchin Astropyga pulvinta Lamarck was studied in Bahía Culebra, Costa Rica. This sea urchin forms aggregations during part of the year and then disappears. I quantified the number of individuals present in a defined area each month, their aggregation behavior between day and night, and their size. Also, temperature and nutrient concentrations of the water were sampled. There were significantly more individuals in aggregations during the colder, upwelling season (December to April). Aggregations consisted of adult individuals that exploit food during the upwelling season. Moreover, these aggregations were used as a refuge by several fish species of high commercial value for the aquarium trade. These sea urchin populations could suffer as extraction of ornamental fishes and urchins increases. Their abundance and behavior should continue to be monitored as an indication of the ecological health of the community.
First Record of a Pearlfish, Carapus mourlani, Inhabiting the Aplysiid Opisthobranch Mollusc Dolabella auricularia
Peter W. Glynn, Ian C. Enochs, John E. McCosker, and Abigail N. Graefe, 593-601
Adult individuals of the pearlfish Carapus mourlani (Petit, 1934) occur commonly in the mantle cavity of the opisthobranch mollusc Dolabella auricularia (Lightfoot, 1786) in shallow marine waters of the Gulf of Chiriquí, Pacific Panamá. Nearly 30% of the molluscan hosts collected during the day on a coral reef contained one or two fish. Feeding observations of a captive fish as well as the intact condition of the host’s ctenidium and other internal organs suggest that C. mourlani is an inquiline commensal and not parasitic. Fish curl around the ctenidium during the day and capture microcrustaceans when the fish emerge from their host at night to feed. From low-light infrared video recordings, Carapus was observed to accurately grasp rapidly swimming amphipods in nearly total darkness and ingest them. This symbiotic relationship appears to benefit Carapus by allowing the fish to avoid predators during the day and to forage at night.
Two New Indo-Pacific Sand Lances of the Genus Ammodytoides (Perciformes: Ammodytidae)
John E. Randall and John L. Earle, 603-612
One new sand lance, Ammodytoides idai Randall & Earle, n. sp., is described from 10 specimens, 67.2–121.3 mm standard length, collected on sand substratum in the depth range of 8–25 m from the D’Entrecasteaux Islands, Papua New Guinea. It is characterized by 44–46 dorsal rays, 21–22 anal rays, 14–16 pectoral rays, 103–107 pored lateral-line scales, two or three small scales dorsally on the opercle, 5–6 + 21–23 gill rakers, 55–58 vertebrae; a series of black spots distally in the dorsal fin, and a blackish posterior border on the caudal fin (at least on adult males), broadening toward lobe tips. A second similar species, A. praematura Randall & Earle, n. sp., is described from a single 61 mm specimen from the Chagos Archipelago, differing in having 48 dorsal rays, 24 anal rays, black dots in the dorsal and anal fins, no submarginal black spots in the dorsal fin, and a curved blackish bar across each lobe of the caudal fin. A key is provided for the eight known species of Ammodytoides.
Association Affairs, 613
Index to Volume 62, 617