Pacific Science 58, no. 1
Abstract: For over 40 yr, the black coral fishery in Hawai‘i has been managed successfully. However, three new developments now threaten sustainability of the resource. First, harvesting pressure on increasingly smaller colonies of both species of commercial black coral (Antipathes dichotoma Pallas and Antipathes grandis Verrill) has increased. Since 1976, the biomass of black coral in the overall bed off Maui, Hawai‘i, has decreased by about 25%. Second, at depths between 80 and 110 m off Maui an alien species, Carijoa riisei (Duchassaing & Michelotti), has overgrown large areas of the substratum as well as many adult colonies of both species of commercial black coral. This invasion may be contributing to a decrease in the recruitment of both species of black coral at shallower depths. Third, increasing sales of black coral jewelry in recent years is also placing more demand on the resource. Taken together, these trends suggest a need for more stringent regulations, including a larger size (height) limit, a reduction in the maximum sustained yield, and possible reassessment of the economics of the fishery. Adoption of these or other measures would help to extend and ensure continued sustainability of the black coral fishery in Hawai‘i and long-term conservation of the resource.
Macrofauna of Laufuti Stream, Taú, American Samoa, and the Role of Physiography in Its Zonation
Robert P. Cook, pp. 7–21
Abstract: Laufuti Stream, on the island of Taú, American Samoa, is a complex interrupted perennial stream, consisting of three accessible sections, lower Laufuti (perennial), middle Laufuti (intermittent), and upper Laufuti (perennial), and the inaccessible falls zone, a series of four sheer, intermittent waterfalls separating lower Laufuti from middle Laufuti. The macrofauna consists primarily of amphidromous species that are relatively common and widespread in the tropical Pacific. However, in comparison with stream communities on Tutuila, Laufuti is unusual. Its shrimp community is more diverse and abundant, dominated by Macrobrachium latimanus, a species neither widespread nor abundant on Tutuila. It also supports a relatively diverse, alien-free freshwater fish community of six species representing three families, Gobiidae, Eleotridae, and Anguillidae, including Anguilla megastoma, a species of limited occurrence on Tutuila. The fish community of Laufuti is similar to that of other tropical Pacific high-island streams in terms of dominant families, but zonation of macrofauna differs. There are no euryhaline fish species, and only Anguilla megastoma occurs above the falls zone. There are seven species of shrimps in lower Laufuti, but only Macrobrachium lar and M. latimanus occur above the falls zone. The severe dispersal barrier represented by the falls zone plus the absence of estuarine conditions, both products of the islands’ geologic history, have produced a pattern of species distributions unlike that of most other tropical Pacific high islands.
Hormophysa cuneiformis (Phaeophyta: Fucales) in Micronesia
Roy T. Tsuda, pp. 23–26
Abstract: Specimens of Hormophysa cuneiformis (J. Gmelin) P. Silva, collected by R. E. DeWreede in July 1968 and by the author in January 1971 from Palau, are documented for the first time and represent the first collections of a member of the family Cystoseiraceae from Micronesia. A single specimen 6 cm tall of H. cuneiformis was collected 4.5 yr later in July 1975 on a reef bench tide pool at Pagan Island in the Northern Mariana Islands by R. Rechebei and was reported in a floristic account of the Chlorophyta and Phaeophyta of the Northern Mariana Islands in 1977. Specimens of this large and conspicuous brown alga have not been reported previously from Palau nor other islands in Micronesia.
Topographic History of the Maui Nui Complex, Hawai‘i, and Its Implications for Biogeography
Jonathan Paul Price and Deborah Elliott-Fisk, pp. 27–45
Abstract: The Maui Nui complex of the Hawaiian Islands consists of the islands of Maui, Moloka‘i, Lana‘i, and Kaho‘olawe, which were connected as a single landmass in the past. Aspects of volcanic landform construction, island subsidence, and erosion were modeled to reconstruct the physical history of this complex. This model estimates the timing, duration, and topographic attributes of different island configurations by accounting for volcano growth and subsidence, changes in sea level, and geomorphological processes. The model indicates that Maui Nui was a single landmass that reached its maximum areal extent around 1.2 Ma, when it was larger than the current island of Hawai‘i. As subsidence ensued, the island divided during high sea stands of interglacial periods starting around 0.6 Ma; however during lower sea stands of glacial periods, islands reunited. The net effect is that the Maui Nui complex was a single large landmass for more than 75% of its history and included a high proportion of lowland area compared with the contemporary landscape. Because the Hawaiian Archipelago is an isolated system where most of the biota is a result of in situ evolution, landscape history is an important determinant of biogeographic patterns. Maui Nui’s historical landscape contrasts sharply with the current landscape but is equally relevant to biogeographical analyses.
Mineralogical Variation in Shells of the Blackfoot Abalone, Haliotis iris (Mollusca: Gastropoda: Haliotidae), in Southern New Zealand
Blair E. Gray and Abigail M. Smith, pp. 47–64
Abstract: The New Zealand blackfoot abalone, Haliotis iris Gmelin, is among the few gastropods that precipitate both calcite and aragonite in their shells. The location, composition, and thickness of these mineral layers may affect color, luster, and strength of the shell, which is locally important in jewelry manufacture. Skeletal mineralogy and shell structure of H. iris from three southern New Zealand locations were determined using X-ray diffractometry, scanning electron micrography, and mineral staining. In H. iris an outer calcitic layer is separated from an inner aragonitic surface by both calcified and noncalcified organic layers running longitudinally through the shell. Skeletal mineralogy within individual shells varies from 29 to 98% aragonite, with older shell having significantly higher aragonite content than young sections. Variation within populations ranges from 40 to 98% aragonite, and among three populations from 34 to 98% aragonite. Shell thickness, too, varies within individual shells from 0.2 to 4.2 mm, with a significant positive relationship with age. Within population variation in shell thickness ranges from 2.1 to 5.4 mm, with no significant difference in shell thickness variation among populations. The high degree of variability within and among individual shells suggests that it is essential to test replicate samples from individual mollusk shells, especially when they have complex bimineral structure.
Annotated Checklist of the Fishes of Wake Atoll
Phillip S. Lobel and Lisa Kerr Lobel, pp. 65–90
Abstract: This study documents a total of 321 fishes in 64 families occurring at Wake Atoll, a coral atoll located at 19° 170´ N, 166° 360´ E. Ten fishes are listed by genus only and one by family; some of these represent undescribed species. The first published account of the fishes of Wake by Fowler and Ball in 1925 listed 107 species in 31 families. This paper updates 54 synonyms and corrects 20 misidentifications listed in the earlier account. The most recent published account by Myers in 1999 listed 122 fishes in 33 families. Our field surveys add 143 additional species records and 22 new family records for the atoll. Zoogeographic analysis indicates that the greatest species overlap of Wake Atoll fishes occurs with the Mariana Islands. Several fish species common at Wake Atoll are on the IUCN Red List or are otherwise of concern for conservation. Fish populations at Wake Atoll are protected by virtue of it being a U.S. military base and off limits to commercial fishing.
Survey and Estimates of Commercially Viable Populations of the Sea Cucumber Actinopyga mauritiana (Echinodermata: Holothuroidea), on Tinian Island, Commonwealth of the Northern Mariana Islands
Michael S. Trianni and Patrick G. Bryan, pp. 91–98
Abstract: A survey was conducted in 1997 to assess commercially viable populations of the surf redfish, Actinopyga mauritiana, and establish a harvest quota for those populations on the island of Tinian. A simple random sampling approach was employed using circular plots as samples. Outer reef flat and reef slope habitats were sampled, producing a total of 333 samples over a 2-month period, with a preharvest population estimate of 71,034. A harvest quota of 17,893 surf redfish was established due to stock depletions on both Rota and Saipan, uncertainty of the density required to ensure successful reproduction of the species, and high degree of uncertainty in the population estimates. It was determined that a stratified sampling approach utilizing either simple proportional or optimal allocation would have resulted in more precise estimates, and these approaches are favored for any future survey work. Population estimates should be revised when more accurate estimates of A. mauritiana habitats become available.
Temporal Variation in Forest Bird Survey Data from Tutuila Island, American Samoa
Holly B. Freifeld, Chris Solek, and Ailao Tualaulelei, pp. 99–117
Abstract: Avian census data from tropical Pacific islands often are limited to brief, one-time surveys. These efforts yield information about species’ presence and distribution but reveal little about variation in abundance through time. This variation may be important for refining and optimizing survey methods and, in turn, assessing habitat preferences, population status, activity patterns, or the impact of disturbance on the abundance and distribution of island birds. The objective of this study was to determine if intra- or interannual patterns exist in the recorded abundance of resident land birds. Forest birds on Tutuila Island, American Samoa, were surveyed each month from 1992 to 1996 at 35 stations on six transects distributed around the island. We used multiple regression techniques to determine that seasonal patterns in detected abundance exist in several species, most notably the Purple-capped Fruit-dove, Ptilinopus porphyraceus, and the Wattled Honeyeater, Foulehaio carunculata. Intraannual patterns may be associated with seasonally variable vocalizations or with concentrations of birds at particular resources. Interannual trends in abundance were not islandwide for any native species during the study period; they were localized and as such may be attributable to small-scale changes in habitat rather than to overall changes in population size. The results of this study, especially that the abundance of nonmigratory island birds is seasonally variable, reinforce the importance of year-round monitoring in the study and conservation of Pacific birds.
Pacific Science Association, pp. 139–141
Pacific Science 58, no. 2
Development of Benthic Sampling Methods for the Coral Reef Assessment and Monitoring Program (CRAMP) in Hawai‘i
Eric Brown, Evelyn Cox, Paul Jokiel, Ku‘ulei Rodgers, William Smith, Brian Tissot, Steve L. Coles, and Jonathan Hultquist, pp. 145-158
Abstract: The Coral Reef Assessment and Monitoring Program (CRAMP) of Hawai‘i was established in 1998 to monitor long-term changes in coral reef benthic communities around the state. Development of the methodology involved analysis of results from previous monitoring programs in Hawai‘i to determine precision and statistical power of various methods to detect change. Additional field trials were conducted to examine factors such as repeatability, appropriate transect length, number of transects, number of samples per transect, cover estimation techniques, observer variation, as well as time and financial constraints. Benthic monitoring methods used previously in Hawai‘i generally showed low statistical power for detecting change due to low precision and small sample size. Field trials indicated that repeatability of conventional techniques using transects or quadrats had high variation and consequently low statistical power unless efforts were made to reposition the sampling units with greater precision. Longer transects (e.g., 25 and 50 m) had higher variability than shorter transects (e.g., 10 m), suggesting that smaller sampling units were more appropriate for the habitats sampled. Variability among observers analyzing the same data was low in comparison with other sources of error. Visual estimation techniques showed low initial cost but were inefficient per survey. Digital video required the highest initial monetary investment but yielded the greatest quantity of data per survey with sufficient quality. The cost effectiveness of the digital video method compared with other techniques increased with more surveys and in more remote situations where logistical expenses were incurred. A within-habitat stratified random sampling design was implemented for the CRAMP design. Fixed transects were chosen to reduce temporal variance and allowed efficient resurveying under the high-wave-energy field conditions typically found in Hawai‘i. The method was designed to detect an absolute change of 10% in benthic cover with high statistical power using 50 points per frame, 20–30 frames per transect, and 8–10 transects per depth. Fixed photoquadrats with high precision and high resolution were included in the design to allow detailed monitoring of coral/algal growth, recruitment, and mortality.
Hawai‘i Coral Reef Assessment and Monitoring Program: Spatial Patterns and Temporal Dynamics in Reef Coral Communities
Paul L. Jokiel, Eric K. Brown, Alan Friedlander, S. Ku‘ulei Rodgers, and William R. Smith, pp.159-174
Abstract: The Hawai‘i Coral Reef Assessment and Monitoring Program (CRAMP) was established to describe the spatial and temporal variation in Hawaiian coral reef communities in relation to natural and anthropogenic factors. Sixty permanent reef sites stratified by depth have been monitored in the main Hawaiian Islands since 1999 and formed the basis for analysis of temporal change over the initial 3-yr period. A rapid assessment technique (RAT) was developed to supplement the monitoring site data and provide much wider geographic coverage, but with a focus on spatial patterns rather than temporal change. Analysis of these data supports and amplifies the results of many other ecological studies on Hawaiian reefs. The data revealed that the major natural factors influencing reef coral community structure in Hawai‘i include depth, wave height, wave direction, island age, rugosity, and sediment grain size. Possible anthropogenic influences and trends also appeared in the data. Areas of decline appear to be concentrated on islands with high human population or in areas suffering from extensive sedimentation. Reefs receiving high terrigenous runoff contain sediments with high organic content. Spatial analysis showed an inverse relationship between percentage organics and coral species richness and diversity. Reef coral communities can undergo natural oscillations over a period of years, so continuation of the CRAMP longer-term monitoring is required to establish long-term (decadal) environmental trends.
Evaluating Effectiveness of a Marine Protected Area Network in West Hawai‘i to Increase Productivity of an Aquarium Fishery
Brian N. Tissot, William J. Walsh, and Leon E. Hallacher, pp.175-188
Abstract: A network of nine Fish Replenishment Areas (FRAs) was established in West Hawai‘i in 2000 in response to declines of reef fishes taken by aquarium collectors. In 1999, we established 23 study sites in FRAs, areas open to collectors, and reference areas (existing protected areas) to collect data both before and after the closure of the FRA network in 2000. To date we have conducted 23 bimonthly fish surveys as well as surveys of the benthic habitats of all sites. Baseline surveys, done before FRA closure, document significant effects of aquarium collector harvesting on selected fishes. On average, aquarium fishes were 26% less abundant in newly established FRAs (formerly open) than in adjacent reference areas. Analysis of postclosure surveys in 2000–2002 using a Before-After-Control-Impact procedure provided evidence of a significant increase in two of the 10 species examined, including the yellow tang (Zebrasoma flavescens), the most collected aquarium fish in Hawai‘i. The recovery of yellow tangs to preexploitation levels in the FRAs was probably due to the high number of newly recruited fishes observed in 2001–2002. Large recruitment events are rare in West Hawai‘i but are likely to be an important factor determining the effectiveness of Marine Protected Areas to help replenish depleted fish populations.
An Attempt to Increase Numbers of Herbivorous Fishes as a Means of Controlling Populations of Fleshy Macroalgae on Coral Reefs in Kane‘ohe Bay, Hawai‘i
Eric J. Conklin and John Stimson, pp.189-200
Abstract: This study was conducted to determine the feasibility of enhancing fish populations as a means of controlling macroalgal populations in Kane‘ohe Bay, O‘ahu, Hawai‘i. Fleshy macroalgae have overgrown corals on reef slopes of Kane‘ohe Bay. Such shifts to fleshy macroalgal domination are often thought to be due to a decrease in abundance of herbivorous fishes. This experiment added 650 herbivorous fishes (acanthurids and scarids) to two reefs, constituting a potential addition of approximately 70% to the total populations of the two reefs. Fish censuses and grazing assays were used to assess the effectiveness of these additions in increasing grazing on these reefs and thereby diminishing the abundance of macroalgae. Fish censuses showed a smaller than expected increase in acanthurid abundance across all reefs, including the control reef, and no increase in scarid abundance. Grazing assays did not show any significant differences between pre- and postaddition. The fishes did not appear to remain on the small isolated reefs to which they were added. It is possible that habitat degradation and lack of shelter on the experimental reefs made them unsuitable for enhanced herbivore populations, because initial and postaddition biomass/unit area was smaller than the published values for many sites. Increasing the abundance of shelter may be necessary to increase the number of fishes on these reefs.
A Rapid Ecological Assessment (REA) Quantitative Survey Method for Benthic Algae Using Photoquadrats with Scuba
Linda B. Preskitt, Peter S. Vroom, and Celia M. Smith, pp. 201-210
Abstract: The challenge of assessing seldom-visited, benthic substrates has created the need for a method to describe benthic communities quickly and efficiently. Macroscale rapid ecological assessments (REAs) of algal assemblages provide managers of coral reefs and other benthic ecosystems with the fundamental descriptive data necessary for continued yearly monitoring studies. The high cost of monitoring marine communities, especially remote sites, coupled with the time limitations imposed by scuba, require that statistically valid data be collected as quickly as possible. A photoquadrat method using a digital camera, computer software for photographic analysis, and minimal data collection in the field was compared with the conventional method of point-intersect (grid) quadrats in estimating percentage cover in subtidal benthic communities. In timed studies, photoquadrats yielded twice the number of quadrats (and an almost infinite number of data points) as conventional methods, provided permanent historical records of each site, and minimized observer bias by having only one observer identifying algae in the field. However, photoquadrats required more post-collection computer analyses of digital photographs than conventional methods. In the manual method, observer bias in algal identification can occur depending on the degree of experience of individual divers. On the other hand, photoquadrats rely on one observer in the field and one observer in the laboratory, standardizing algal identification. Overall, photoquadrats do not yield the finer resolution in diversity that was found using point-intersect quadrats but do provide a more precise estimate of percentage cover of the abundant species, as well as establishing a permanent visual record in the time allowed by work with other teams.
2000–2002 Rapid Ecological Assessment of Corals (Anthozoa) on Shallow Reefs of the Northwestern Hawaiian Islands. Part 1: Species and Distribution
James E. Maragos, Donald C. Potts, Greta Aeby, Dave Gulko, Jean Kenyon, Daria Siciliano, and Dan VanRavenswaay, pp. 211-230
Abstract: Rapid Ecological Assessment (REA) surveys at 465 sites on 11 reefs in the Northwestern Hawaiian Islands (NWHI) inventoried coral species, their relative abundances, and their distributions during 2000–2002. Surveys (462) around the 10 islands were in depths of <less than or equal to> 20 m, and three surveys on the submerged Raita Bank were in depths of 30–35 m. Data from 401 REA sites met criteria for quantitative analysis. Results include 11 first records for stony coral species in the Hawaiian Archipelago and 29 range extensions to the NWHI. Several species may be new to science. There are now 57 stony coral species known in the shallow subtropical waters of the NWHI, similar to the 59 shallow and deep-water species known in the better-studied and more tropical main Hawaiian Islands. Coral endemism is high in the NWHI: 17 endemic species (30%) account for 37–53% of the abundance of stony corals on each reef of the NWHI. Three genera (Montipora, Porites, Pocillopora) contain 15 of the 17 endemic species and most of the endemic abundance. Seven Acropora species are now known from the central NWHI despite their near absence from the main Hawaiian Islands. Coral abundance and diversity are highest at the large, open atolls of the central NWHI (French Frigate, Maro, Lisianski) and decline gradually through the remaining atolls to the northwest (Pearl and Hermes, Midway, and Kure). Stony corals are also less abundant and less diverse off the exposed basalt islands to the southeast (Nihoa, Necker, La Pérouse, Gardner), where soft corals (Sinularia, Palythoa) are more abundant. Exposure to severe wave action appears to limit coral development off these small islands and surrounding deep platforms. Temperature extremes and natural accumulation of lagoon sediments may contribute to decline of coral species and abundance at the northwestern end of the chain.
Economic Valuation of the Coral Reefs of Hawai‘i
Herman S. J. Cesar and Pieter J. H. van Beukering, pp. 231-242
Abstract: Hawai‘i’s coral reef ecosystems provide many goods and services to coastal populations, such as fisheries and tourism. They also form a unique natural ecosystem, with an important biodiversity value as well as scientific and educational value. Also, coral reefs form a natural protection against wave erosion. Without even attempting to measure their intrinsic value, this paper shows that coral reefs, if properly managed, contribute enormously to the welfare of Hawai‘i through a variety of quantifiable benefits. Net benefits are estimated at $360 million a year for Hawai‘i’s economy, and the overall asset value of the state of Hawai‘i’s 1660 km2 (410,000 acres) of potential reef area in the main Hawaiian Islands is estimated at nearly $10 billion.
Ecological Economic Modeling of Coral Reefs: Evaluating Tourist Overuse at Hanauma Bay and Algae Blooms at the Kıhei Coast, Hawai‘i
Pieter J. H. van Beukering and Herman S. J. Cesar, pp. 243-260
Abstract: In this paper we present the first ecological economic model of coral reefs in Hawai‘i. This model contains the main elements required to assess the full picture of coral reef management and thereby enables scientists and managers to evaluate ecological and economic impacts effectively. The model is applied to two case studies, tourist overuse in Hanauma Bay, O‘ahu, and algae blooms along the Kıhei coast, Maui. The Hanauma study showed that visitors are willing to pay much more for their experience (around $10) than they are currently doing and that the net benefits of the education program (around $100 million) greatly exceed the cost of the program (around $23 million) over time. The Kıhei coast study concluded that the algae problem causes large losses of real estate value and hotel business and that mitigation could result in benefits of $30 million over time. This would justify major investments in lowering nutrient discharges in the coastal zone.
Impact of Stream Hardening on Water Quality and Metabolic Characteristics of Waimanalo and Kane‘ohe Streams, O‘ahu, Hawaiian Islands
Edward A. Laws and Lauren Roth, pp. 261-280
Abstract: Kane‘ohe and Waimanalo Streams on the windward side of the island of O‘ahu in the Hawaiian Islands have been hardened to prevent flooding. The hardening process has involved elimination of the natural riparian habitat and replacement of the natural stream channel with a concrete-lined conduit having vertical walls and a broad, flat bottom. The shallow depth of the water column and absence of shade have resulted in temperatures that average as much as 4–5 C above ambient and rise as high as 32 C during daylight hours. Unlike most low-order streams, the hardened sections of both streams are autotrophic, as evidenced by elevated pH values and O2 concentrations as high as 150% of saturation. Several allochthonous inputs, one from a storm sewer and the other from a natural spring, introduced water with anomalously low O2 concentrations and very high nitrate concentrations. The absence of sediments in the hardened sections of the streams precludes natural sedimentary microbial proceses, including denitrification. Nitrate concentrations in a section of Waimanalo Stream with a natural streambed drop dramatically from values in excess of 400 <mu>M to concentrations less than 10 <mu>M at the head of the estuary. Although some of this decline is due to dilution with seawater, the concentration of nitrate at the head of the estuary is only 10% of the value that could be explained by dilution effects. Biological processes associated with a natural streambed thus appear very important to functionality of the streams and in particular to their ability to process allochthonous nutrient inputs in a way that minimizes impacts on the nearshore environment. Prevention of flooding can be accomplished by mechanisms that do not involve elimination of riparian buffer zones and destruction of channel habitat. To maintain water quality and stream functionality, it is important that these alternative methods of flood control be utilized. Converting natural streams to storm sewers is an unenlightened way to address flooding problems.
Anthropogenic and Natural Stresses on Selected Coral Reefs in Hawai‘i: A Multidecade Synthesis of Impact and Recovery
Steven J. Dollar and Richard W. Grigg, pp. 281-304
Abstract: In 2002, quantitative phototransect surveys documenting coral community structure off three coastal resorts in Hawai‘i were repeated to produce long-term data sets of 12 to 22 yr duration. At the first site, in Honolua Bay off the Kapalua Resort on Maui, a runoff event from surrounding pineapple fields following a winter storm in early 2002 deposited sediment on the inner reef that remained in the bay for at least 6 months. Between 1992 and 2002 survey data showed that significant declines in coral cover occurred on seven of eight transects, causing an overall reduction in coral cover of about 33% throughout the entire bay. Rainfall records indicate that the 2002 storm was of relatively small magnitude; however subsequent resuspension and flushing by waves did not take place for several months, exacerbating the smothering effects of the sediment. Periodic sedimentation events of various magnitude and duration have resulted in cycles of damage and recovery that have produced a coral community that reflects intermediate disturbance and a coral community structure dominated by sediment-resistant species. The two other long-term surveys, off Mauna Lani Resort on the west coast of the island of Hawai‘i (1983–2002), and Princeville Resort on the north shore of Kaua‘i (1980–2002), both revealed a pattern of consistent increase in coral cover at all stations. At these open coastal sites, anthropogenic effects are undetectable relative to natural factors that affect coral community structure. A lack of maximum wave events during the interval between surveys may partially explain the increase in coral cover. Activities from shoreline development appeared to have no effect on coral community structure during the study interval. The results of these three studies suggest a framework for coral reef management in Hawai‘i by concentrating efforts on embayments and areas with restricted circulation. Because such areas compose less than 10% of the coastal areas, the overall condition of the majority of coral reefs in Hawai‘i is relatively good. Nevertheless, embayments are major recreational sites and it is these environments for which we suggest that the major need for management exists and should be focused. On a global scale, concerns of catastrophic loss from anthropogenic impact to coral reefs may be valid in many areas of the world, but they do not accurately depict the condition of coral reefs in Hawai‘i.
El Nino Influence on Holocene Reef Accretion in Hawai‘i
John Rooney, Charles Fletcher, Eric Grossman, Mary Engels, and Michael Field, pp. 305-324
Abstract: New observations of reef accretion from several locations show that in Hawai‘i accretion during early to middle Holocene time occurred in areas where today it is precluded by the wave regime, suggesting an increase in wave energy. Accretion of coral and coralline algae reefs in the Hawaiian Islands today is largely controlled by wave energy. Many coastal areas in the main Hawaiian Islands are periodically exposed to large waves, in particular from North Pacific swell and hurricanes. These are of sufficient intensity to prevent modern net accretion as evidenced by the antecedent nature of the seafloor. Only in areas sheltered from intense wave energy is active accretion observed. Analysis of reef cores reveals patterns of rapid early Holocene accretion in several locations that terminated by middle Holocene time, ca. 5000 yr ago. Previous analyses have suggested that changes in Holocene accretion were a result of reef growth ‘‘catching up’’ to sea level. New data and interpretations indicate that the end of reef accretion in the middle Holocene may be influenced by factors in addition to sea level. Reef accretion histories from the islands of Kaua‘i, O‘ahu, and Moloka‘i may be interpreted to suggest that a change in wave energy contributed to the reduction or termination of Holocene accretion by 5000 yr ago in some areas. In these cases, the decrease in reef accretion occurred before the best estimates of the decrease in relative sea-level rise during the mid-Holocene high stand of sea level in the main Hawaiian Islands. However, reef accretion should decrease following the termination of relative sea-level rise (ca. 3000 yr ago) if reef growth were ‘‘catching up’’ to sea level. Evidence indicates that rapid accretion occurred at these sites in early Holocene time and that no permanent accretion is occurring at these sites today. This pattern persists despite the availability of hard substrate suitable for colonization at a wide range of depths between 30 m and the intertidal zone. We infer that forcing other than relative sea-level rise has altered the natural ability to support reef accretion on Hawaiian insular shelves. The limiting factor in these areas today is wave energy. Numbers of both large North Pacific swell events and hurricanes in Hawai‘i are greater during El Nino years. We infer that if these major reeflimiting forces were suppressed, net accretion would occur in some areas in Hawai‘i that are now wave-limited. Studies have shown that El Nino/Southern Oscillation (ENSO) was significantly weakened during early-mid Holocene time, only attaining an intensity similar to the current one ca. 5000 yr ago. We speculate that this shift in ENSO may assist in explaining patterns of Holocene Hawaiian reef accretion that are different from those of the present and apparently not related to relative sea-level rise.
Ecology of the Invasive Red Alga Gracilaria salicornia (Rhodophyta) on O‘ahu, Hawai‘i
Jennifer E. Smith, Cynthia L. Hunter, Eric J. Conklin, Rebecca Most, Thomas Sauvage, Cheryl Squair, and Celia M. Smith, pp. 325-344
Abstract: The red alga Gracilaria salicornia (C. Agardh) E. Y. Dawson was introduced intentionally to two reefs on O‘ahu, Hawai‘i, in the 1970s for experimental aquaculture for the agar industry. Some 30 yr later, this species has spread from the initial sites of introduction and is now competing with native marine flora and fauna. The goals of this study were to quantify various aspects of G. salicornia ecology in Hawai‘i in an effort to develop control or eradication tools. Experimental plots were established to determine cover and biomass of G. salicornia per square meter and to determine the amount of time and person hours needed to remove G. salicornia from these plots. Substantial amounts of G. salicornia become dislodged from the reef during large wave events and periodically become deposited onto the beach in front of the Waikıkı Aquarium. Algal beach wash biomass was quantified and positive relationships were established between swell height and the amount of algae that washed up onto the beach in this location. We then quantified the ability of G. salicornia vegetative fragments to regrow after desiccation to determine if algal biomass stranded on shore survives the tidal cycle until being washed back out on the reef at high tide. Gracilaria salicornia was remarkably resistant to temperature, salinity, and chemical treatments examined as possible in situ control options. Herbivore preference tests showed that a native Gracilaria species is consumed far more frequently than the alien congener. Finally, large-scale community volunteer efforts were organized to remove drifting G. salicornia fragments from the reef area in front of the Waikıkı Aquarium. Over 20,000 kg of alien algal fragments were removed from this location in five 4-hr cleanup events. However, based on G. salicornia growth rates, ability to fragment, physical tolerance, and low herbivory, it is clear that a large-scale dedicated effort will be needed to control this invasive species on Waikıkı’s reefs.
Pacific Science Association, pp. 345-348
Pacific Science 58, no. 3
Threat of Invasive Alien Plants to Native Flora and Forest Vegetation of Eastern Polynesia
Jean-Yves Meyer, pp. 357-376
Abstract: Eastern Polynesia, a phytogeographical subregion of Polynesia in the Pacific Ocean, comprises the archipelagoes of the Cook Islands, the Austral Islands, the Society Islands, the Tuamotu Islands, the Marquesas Islands, the Gambier Islands, the Pitcairn Islands, and Rapa Nui, which is the easternmost inhabited island of Polynesia. It consists of a total of about 140 tropical to subtropical oceanic islands that are among the most remote in the world, being over 3,000 km distant from the nearest continents. Because of this strong geographic isolation, the relatively young geological age, and small terrestrial surface (less than 4,000 km2) of these islands, the native flora of eastern Polynesia is impoverished, disharmonic, and with a relative low number of endemic genera (12). However, some high volcanic islands within these archipelagoes display a great diversity of habitats and a highly endemic flora (e.g., 50% for the vascular plants in Nuku Hiva, 45% in Tahiti) with striking cases of adaptative radiation (e.g., in the genera Bidens, Cyrtandra, Glochidion, Myrsine, and Psychotria). Most of these endemic taxa are restricted to montane rain forests and cloud forests. These upland wet forests are not directly threatened by habitat destruction by humans or disturbance by large mammals but rather by invasive alien plants. Native forests of eastern Polynesian islands are invaded by aggressive introduced species (e.g., Lantana camara and Psidium cattleianum in most island groups; Syzygium jambos in Pitcairn, Tahiti, and Nuku Hiva; Ardisia elliptica, Cestrum nocturnum, Spathodea campanulata in Tahiti and Rarotonga; Rubus rosifolius in the Society Islands, Hiva Oa, and Rapa Iti). Therefore, one of the highest priorities for the long-term conservation of the original native flora and forest vegetation of eastern Polynesia should be given to the study (invasion dynamics and ecological impacts) and control (strategy and methods) of the current invasive alien plants and to the early detection and eradication of potential plant invaders. Eastern Polynesia, with its small, diverse, and isolated oceanic islands, also offers opportunities to test hypotheses on the vulnerability of islands to invasion by alien species, with or without disturbance.
Abstract: Specimens of actiniarians from the Gulf of California having a column densely covered with vesicles or verrucae have been attributed to one of three species: Anthopleura dowii, Bunodactis mexicana, or Bunodosoma californica. These three species are difficult to distinguish and are at least partly synonymous: Bunodosoma californica is a pro parte synonym of A. dowii and Bunodactis mexicana is a junior synonym of A. dowii. However, based on anatomy, coloration patterns, types of cnidae in the column, and habitat preferences, I discern three distinct species. I describe specimens attributed to Bunodactis mexicana not belonging to A. dowii as Isoaulactinia hespervolita, n. sp. I redescribe Bunodosoma californica and A. dowii and designate a lectotype for Bunodosoma californica to resolve taxonomic confusion.
Long-Legged Ants, Anoplolepis gracilipes (Hymenoptera: Formicidae), Have Invaded Tokelau, Changing Composition and Dynamics of Ant and Invertebrate Communities
Philip J. Lester and Alapati Tavite, pp. 391-402
Abstract: This report documents the ongoing invasion of the Tokelau atolls by the long-legged ant, Anoplolepis gracilipes ( Jerdon). These ants were collected from two of the three Tokelau atolls. On the island of Fenua Fala of Fakaofo Atoll, long-legged ants appear to be a recent arrival and occur in only a small area around one of the two ports. Most of the inhabited islands of Vao and Motuhuga on Nukunonu Atoll have been invaded, in addition to several of the uninhabited, forested islands. Despite this ant having been previously recorded from at least one island of Fakaofo and Nukunonu, these appear to be new invasions. Densities of up to 3,603 A. gracilipes per pitfall trap were caught per 24 hr. A significant reduction in ant species diversity was observed with increasing A. gracilipes densities. Densities of this ant were not uniformly high, perhaps due to variation in food availability. Prey such as crabs, ant colonies, and other insects were directly observed being attacked, and long-legged ants were observed to feed on honeydew produced by high densities of aphids, mealybugs, and scale insects on a variety of plants. Interspecific competition was investigated as an additional mechanism for the successful invasion. Long-legged ants found and removed bait faster than the dominant resident ant species, Paratrechina longicornis (Latreille), in forested areas of Nukunonu Island, though needing smaller numbers of recruits to achieve this result. This A. gracilipes invasion is of serious concern for the biodiversity of Tokelau and probably many of the other Pacific islands where these ants have invaded.
New Records of the Fish Genus Grammatonotus (Teleostei: Perciformes: Percoidei: Callanthiidae) from the Central Pacific, Including a Spectacular Species in the Northwestern Hawaiian Islands
Bruce C. Mundy and Frank A. Parrish, pp. 403-418
Abstract: A second species of Grammatonotus from the Hawaiian Islands, tentatively identified as G. macrophthalmus Katayama, Yamamoto & Yamakawa (Callanthiidae), is recorded from French Frigate Shoals and the Northampton Seamount based on observations from a research submersible. In the absence of collected specimens, identification was made by comparing characters visible in video images with previously published images and descriptions. The fish were observed from 340 to 440 m at or near rocky habitats with crevices. All of the observations were near current-swept areas that supported gold coral (Gerardia sp.) colonies, although the fish were never seen within the colonies. A habitat feature important for both Grammatonotus and Gerardia, such as current or planktonic food supply, may therefore influence distribution of the fish. Extensive fish surveys conducted in comparable depths at other areas of the archipelago have not encountered this species, with one poorly documented exception from trawling surveys. Two other range extensions of Grammatonotus are included herein: Grammatonotus laysanus Gilbert from the Line Islands with a specimen collected at Christmas Island at 274 m and an unidentified Grammatonotus juvenile from the Tuamotu Archipelago at 705 m. Our examination of specimens and review of previous records of Grammatonotus indicate that this genus needs taxonomic revision.
Plant-Parasitic Algae (Chlorophyta: Trentepohliales) in American Samoa
Fred E. Brooks, pp. 419-428
Abstract: A survey conducted between June 2000 and May 2002 on the island of Tutuila, American Samoa, recorded filamentous green algae of the order Trentepohliales (Chlorophyta) and their plant hosts. Putative pathogenicity of the parasitic genus Cephaleuros and its lichenized state, Strigula, was also investigated. Three genera and nine species were identified: Cephaleuros (five spp.), Phycopeltis (two spp.), and Stomatochroon (two spp.). A widely distributed species of Trentepohlia was not classified. These algae occurred on 146 plant species and cultivars in 101 genera and 48 families; 90% of the hosts were dicotyledonous plants. Cephaleuros spp. have aroused worldwide curiosity, confusion, and concern for over a century. Their hyphaelike filaments, sporangiophores, and associated plant damage have led unsuspecting plant pathologists to misidentify them as fungi, and some phycologists question their parasitic ability. Of the five species of Cephaleuros identified, C. virescens was the most prevalent, followed by C. parasiticus. Leaf tissue beneath thalli of Cephaleuros spp. on 124 different hosts was dissected with a scalpel and depth of necrosis evaluated using a fourpoint scale. No injury was observed beneath thalli on 6% of the hosts, but fullthickness necrosis occurred on leaves of 43% of hosts. Tissue damage beneath nonlichenized Cephaleuros thalli was equal to or greater than damage beneath lichenized thalli (Strigula elegans). In spite of moderate to severe leaf necrosis caused by Cephaleuros spp., damage was usually confined to older leaves near the base of plants. Unhealthy, crowded, poorly maintained plants tended to have the highest percentage of leaf surface area affected by Trentepohliales. Parasitic algae currently are not a problem in American Samoa because few crops are affected and premature leaf abscission or stem dieback rarely occur.
Experimental Release of Endemic Partula Species, Extinct in the Wild, into a Protected Area of Natural Habitat on Moorea
Trevor Coote, Dave Clarke, Carole S. Hickman, James Murray, and Paul Pearce-Kelly, pp. 429-434
Abstract: Extinction of tree snails of the genus Partula on Moorea, following introduction of the predatory snail Euglandina rosea, has challenged conservation biology during years of successive captive breeding of small rescued populations. An experimental release of three Partula species into a predator-proof patch of native forest on Moorea was designed to test effectiveness of physical and chemical methods of predator exclusion and to evaluate behavior of animals bred for up to six generations in highly artificial environments. At the close of the experimental release, there had been multiple incursions of E. rosea, and too few Partula spp. remained to assess effects of captive breeding on ecological responses. However, results demonstrated the effectiveness of the exclosure under ideal maintenance and monitoring. Captive breeding methods were validated by reproduction and growth to sexual maturity in the wild as well as retention of genetic variability in the form of persistent color polymorphism in one species.
Benthic Diatom Assemblages in an Abalone (Haliotis spp.) Habitat in the Baja California Peninsula
David A. Siqueiros Beltrones and Guillermina Valenzuela Romero, pp. 435-446
Abstract: Diatom assemblages from an abalone (rocky) habitat were sampled in April and November 1999 and in April 2000 on the western side of Isla Magdalena, B.C.S., México. Overall 236 taxa were recorded, including 10 new records, and 56 species that have been observed exclusively in this type of habitat in the Baja California peninsula. The rocky habitat surveyed is much more complex than expected because of different substrata (rock, fleshy macroalgae, crustose corallines, erect corallines) available for colonization by diatoms at Isla Magdalena. Although epilithic forms were identified, epiphytic diatoms were more abundant. Thus the potential diet for abalone and other grazers is more diverse than previously assumed (i.e., that mainly epilithic diatoms would be their potential food source). A variation in structure was observed between the two assemblages sampled in April because of a change in the species composition of the samples. Most of the rock surface was covered by macroalgae. Thus, the diatom associations consisted mainly of epiphytic forms. The high values of H’ corresponded to high species richness (S), whereas higher dominance <lambda> corresponded to low S. The highest estimated value of H’ was 5.39 (S 1/4 82) for the November 1999 rock-Lithophyllum assemblage. Similarity measurements, using Morisita’s index, indicate that differences in species composition and in association structure may represent a distribution of diatom taxa according to available substrata within the habitat rather than a year-to-year or seasonal variation.
Land Snail Fauna of Me Aure Cave (WMD007), Moindou, New Caledonia: Human Introductions and Faunal Change
Robert H. Cowie and J. A. Grant-Mackie, pp. 447-460
Abstract: The land snail fauna excavated from a cave at Me´ Aure´ on the central southwestern coast of New Caledonia represents a period of over 3000 yr, from before human arrival in the island to the present. The material excavated represents 20 terrestrial species in nine families. The fauna reflects the overall land snail fauna of New Caledonia in being dominated by small snails in the families Charopidae and Rhytididae, with large Placostylus species (Bulimulidae) present and minor representation of other families. Two alien species are present: Allopeas gracile, probably introduced before European arrival, and Achatina fulica, introduced in 1972. There are suggestions of change in the composition of the fauna, perhaps associated with the arrival of Europeans and the replacement of native by alien vegetation, with Andrefrancia vetula and possibly A. saisseti declining and Rhytida aulacospira increasing.
Degradation and Recovery of Vegetation on Kaho‘olawe Island, Hawai‘i: A Photographic Journey
Steven D. Warren, pp. 461-478
Abstract: Over the past five centuries, the Hawaiian island of Kaho‘olawe has suffered the ravages of slash-and-burn agriculture, interisland warfare, severe overgrazing by domestic and feral livestock, and military training. During the 1930s, Bishop Museum personnel photographed portions of Kaho‘olawe and documented the degraded condition of the island. Many of the same locations were photographed during the early 1990s. Paired comparisons of the photographs illustrate a remarkable recovery of the vegetation on the island. The recovery is attributable to early introductions of plant species for livestock forage, followed by eradication of the livestock, and more recent erosion control and revegetation efforts. Barring renewal of environmentally deleterious activities, the outlook for Kaho‘olawe is promising.
Killer Whale Predation on a Leatherback Turtle in the Northeast Pacific
Robert L. Pitman and Peter H. Dutton, pp. 497-498
Abstract: In November 2001, we observed a herd of killer whales (Orcinus orca) preying upon a leatherback turtle (Dermochelys coriacea) off the coast of California. Here we provide details of the event and speculate that oceanic killer whales may have less specialized diets than nearshore populations. We also suggest that killer whale predation should be considered a factor in the recovery of this critically endangered sea turtle.
Pacific Science Association, pp. 499-501
Pacific Science 58, no. 4
Tropical Transpacific Shore Fishes
D. Ross Robertson, Jack S. Grove, and John E. McCosker, pp. 507-565
Abstract: Tropical transpacific fishes occur on both sides of the world’s largest deep-water barrier to the migration of marine shore organisms, the 4,000- to 7,000-km-wide Eastern Pacific Barrier (EPB). They include 64 epipelagic oceanic species and 126 species of shore fishes known from both the tropical eastern Pacific (TEP) and the central and West Pacific. The broad distributions of 19 of 39 circumglobal transpacific species of shore fishes offer no clues to the origin of their TEP populations; TEP populations of another 19 with disjunct Pacific distributions may represent isthmian relicts that originated from New World populations separated by the closure of the Central American isthmus. Eighty species of transpacific shore fishes likely migrated eastward to the TEP, and 22 species of shore fishes (12 of them isthmian relicts) and one oceanic species likely migrated westward from the TEP. Transpacific species constitute ~12% of the TEP’s tropical shore fishes and 15–20% of shore fishes at islands on the western edge of the EPB. Eastward migrants constitute ~7% of the TEP’s shore-fish fauna, and a similar proportion of TEP endemics may be derived from recent eastward immigration. Representation of transpacific species in different elements of the TEP fauna relates strongly to adult pelagic dispersal ability—they constitute almost all the epipelagic oceanic species, ~25% of the inshore pelagic species, but only 10% of the demersal shore fishes. Taxa that have multiple pelagic life-history stages are best represented among the transpacific species. Among demersal teleosts that have pelagic larvae, pelagic spawners are better represented than demersal spawners among transpacific species, perhaps because offshore larval development and longer pelagic larval durations provide the former with greater dispersal capabilities. There are strong phylogenetic effects on representation in the transpacific fauna: (1) elasmobranchs are proportionally better represented than teleosts, even teleosts with more pelagic life-history stages; (2) a pelagic juvenile stage with great dispersal potential allows tetraodontiforms that produce demersal or pelagic eggs to be well represented; and (3) various speciose central Pacific families with ‘‘adequate’’ larval dispersal characteristics lack transpacific species. El Niños potentially enhance eastward migration by increasing eastward flow and halving transit times across the EPB. However, that effect may be offset by low productivity and high temperatures in those eastbound flows. There is little clear evidence of strongly increased migration across the EPB during El Niños, including recent extreme events (1982–1983 and 1997–1998). During such events shore fishes in the TEP experience range expansions and become locally abundant at marginal areas such as the Galápagos, changes that can be confused with increased migration across the EPB. Although there is a strong bias toward eastward migration among the transpacific shore fishes, there likely is much more westward migration than previously realized: 20–25% of transpacific species may have migrated in that direction. Stronger eastbound than westbound currents can account for this bias. Westward migrants have better developed pelagic dispersal characteristics than many eastward migrants, suggesting that westward migration is more difficult. Many westward migrants associate with flotsam and flotsam-mediated migration is more likely to be westward. All westward migrants occur at Hawai‘i, but only about one-fifth of them at the Marquesas. This bias may be due to: Hawai‘i being a larger target and in the path of most of the flotsam dispersal from the TEP; an eastward current that impinges on the Marquesas, reducing westward arrivals; and most propagules dispersing toward the tropical Marquesas originating in the temperate eastern Pacific. However, the Hawaiian Islands also are much better sampled than the Marquesas. Although the TEP reef-fish fauna may be depauperate relative to that of the Indo-Malayan ‘‘center of diversity,’’ it is as rich as the faunas of islands on the western side of the EPB. Hence a preponderance of eastward migration does not represent a response to a richness gradient across that barrier. There is little evidence that a paucity of ecological groups in the native TEP fauna is primarily responsible for the structure of the eastward-migrant fauna. Rather, eastward migrants may simply represent a cross section of those in the donor fauna, tempered by phylogenetic variation in dispersal ability. Because few central Pacific fishes can live only on live corals and coral reefs, the rarity of such reefs in the TEP is unlikely to strongly limit eastward migration. Differences between oceanic and adjacent continental reef-fish faunas in the West Pacific indicate that each is strongly tied to its respective habitat. Hence, the rarity in the TEP of the (overwhelmingly) most abundant habitat present in the central Pacific—tropical oceanic reefs—may strongly limit migration in both directions across the EPB: there is little suitable habitat for eastward migrants in the TEP and few suitable species and tiny source populations for westward migrants. The global effects that oceanic/continental habitat differences have on reef-fish biogeography need further assessment. Genetic data on ~18% of the transpacific species indicate: that conspecific populations of oceanic species (especially) and shore fishes are genetically well connected across the EPB; that circumtropical taxa in the TEP include isolated isthmian relicts and recent eastward migrants; that all five TEP species of one circumtropical genus (Thalassoma) were derived by several eastward invasions after the closure of the Isthmus of Panama; that some isolated Hawaiian central Pacific populations were established by postisthmian invasion from the TEP; and that Indo-central Pacific species unsuspectedly can co-occur with their endemic sibling sisters in the TEP. Genetic data support distributional data that indicate a strong preponderance of eastward migration across the EPB but also more westward migration than previously thought. Future genetic studies should resolve a question that distributional data cannot: how many widespread presumed eastward-migrant transpacific species actually originated by westward migration from the TEP?
Spatial Distribution of Fish Larvae in a Bay of the Gulf of California (June and November 1997)
Martha Peguero-Icaza and Laura Sánchez-Velasco, pp. 567-578
Abstract: Bahía Concepción is one of the largest coastal bodies of water on the peninsular side of the Gulf of California, which is characterized by great fish species diversity. Spatial distributions of fish larvae in Bahía Concepción during June and November 1997 were analyzed; these months were representative of the extreme hydrographic conditions during an annual cycle in the Gulf. Zooplankton samples (333-µm conical net) and conductivity, temperature, and depth data were obtained at each sampling station. The Bray-Curtis dissimilarity index defined three groups of stations in June (mouth, central, and interior) and two in November (mouth and central-interior), which vary in species composition and dominance. In June, Gerreidae (Eucinostomus gracilis) and Clupeidae (Opisthonema sp.) larvae were the dominant species in the bay mouth; Sciaenidae type 1, Clupeidae (Harengula thrissina), and Pomacentridae (Stegastes rectifraenum) larvae were the dominant species in the central bay; and Gerreidae (E. dowii) larvae in the bay interior. The differentiation of three groups is associated with variations in hydrographic conditions recorded from the mouth to the bay interior, coinciding with a well-defined thermocline throughout the bay as a result of weak winds prevailing in the central Gulf region. In November, Mullidae and Clupeidae (Etrumeus teres) larvae were the dominant taxa in the bay mouth, and Gobiidae (Ilypnus gilberti) and Blenniidae (Hypsoblennius gentilis) larvae dominated in the central and interior bay. The similarity of the larval composition of the central and interior bay is associated with a straight spatial gradient of temperature and salinity and homogeneity in the water column; this condition was caused by strong winds and tides that affect the region in late fall. In addition, the presence of mesopelagic species (e.g., Vinciguerria lucetia) in the bay interior during November indicates a clear influence of the Gulf waters in the bay at that time, possibly as a result of intensive mixing.
A Pygmy Blue Whale (Cetacea: Balaenopteridae) in the Inshore Waters of New Caledonia
Philipe Borsa and Galice Hoarau, pp. 579-584
Abstract: The occurrence of a blue whale is reported for the first time for the New Caledonian archipelago. The whale, a juvenile male in poor condition, entered the shallow inshore waters of the coral reef lagoon (22° 19–24′ S, 166° 46–52′ E) where it spent at least 1 month until it was killed by whaler sharks on 27 January 2002. Live observations, examination of photographic documents, and skull osteology indicated that this was a pygmy blue whale, Balaenoptera musculus brevicauda. Nucleotide sequences of PCR-amplified fragments of its mitochondrial DNA were determined and compared with the few published homologous sequences of North Atlantic blue whales, B. m. musculus, but no obvious differences were apparent.
Population Size and Natural History of Mariana Fruit Bats (Chiroptera: Pteropodidae) on Sarigan, Mariana Islands
Gary J. Wiles and Nathan C. Johnson, pp. 585-596
Abstract: Based on count results, we estimated the population of Mariana fruit bats (Pteropus mariannus Desmarest) on Sarigan, Mariana Islands, to number 150–200 bats in 1999, 185–235 bats in 2000, and about 300–400 bats in 2001. Our results, plus those of two previous surveys, indicate that bat abundance on the island probably remained relatively stable at about 125–235 animals during much of the period from 1983 to 2000, then increased suddenly in 2001, most likely due to immigration from a neighboring island. Sarigan’s population differs from those of larger islands in the archipelago by usually having smaller roost sizes, typically 3–75 bats, and large numbers of solitary bats that at times comprise up to half of the population. Colonies and smaller aggregations were composed primarily of harems with multiple females, whereas a nearly equal sex ratio occurred among solitary animals. Colonies roosted in isolated coconut trees in open grasslands and in native forest stands of various sizes, but avoided dense coconut forest. An estimated 30–50% of harem and solitary females possessed young in July 1999. Bats were recorded feeding on just six species of plants, which partly reflects the island’s impoverished flora. We speculate that fruit bat abundance on Sarigan is limited primarily by food availability rather than hunting losses, in contrast to some other islands in the Marianas. Our study supports the contention that populations of P. mariannus in the northern Marianas are usually sedentary, but that interisland movements of larger numbers of bats may occur rarely.
New Hyocrinid Crinoids (Echinodermata) from Submersible Investigations in the Pacific Ocean
Michel Roux, pp. 597-613
Abstract: A few specimens belonging to the deep-sea family Hyocrinidae (stalked Crinoidea, Echinodermata) collected by submersible in the eastern and western Pacific Ocean are described. Laubiericrinus pentagonalis, n. genus, n. sp., from the North Fiji Rise is the first discovery of a hyocrinid crinoid with a pentaradially symmetrical stalk. Hyocrinus biscoitoi, n. sp., from the East Pacific Rise attains large size and has close affinities with H. giganteus from Horizon Seamount. Additional information is given concerning H. foelli found near cold seeps on the Mexican continental margin; H. cyanae, previously collected on New Caledonian slopes; and Calamocrinus diomedae from the Cocos Ridge and Galápagos slopes. For the latter, the first young specimens known document ontogenetic trends in this famous species.
A Prehistoric, Noncultural Vertebrate Assemblage from Tutuila, American Samoa
David W. Steadman and Gregory K. Pregill, pp. 615-624
Abstract: Ana Pe‘ape‘a is a small cave on the southern shore of Tutuila, American Samoa. Excavations at Ana Pe‘ape‘a yielded 13,600+ bones of small vertebrates, dominated (>95%) by the nonnative Pacific Rat, Rattus exulans. Represented in the owl-derived bone deposit are two species that no longer occur on Tutuila, the Pacific Boa (Candoia bibroni) and the Sooty Crake (Porzana tabuensis). Based on bone counts, C. bibroni was the second most common species at the site. The third most common, the Sheath-tailed Bat (Emballonura semicaudata), is extremely rare on Tutuila today. Compared with bone records in nearby Tonga, we believe that the deposit at Ana Pe‘ape‘a, with a radiocarbon date of A.D. 445 to 640, is at least 1,000 yr too young to be dominated by extinct species.
Distribution of the Chuuk Islands Giant Millipede, Acladocricus setigerus (Spirobolida: Rhinocricidae), and Identification of Its Defensive Compounds
Donald W. Buden, Athula Attygale, and Xiaogang Wu, pp. 625-636
Abstract: The spirobolidan millipede Acladocricus setigerus (Silvestri, 1897) grows to at least 155 mm long and is so far known only from Chuuk Islands, Micronesia. It occurs mainly in well-shaded habitats, usually on the forest floor and on tree trunks. It sprays defensive secretions from paired, lateral ozopores on trunk segments; the major compounds, identified here for the first time, are benzoquinones. The secretion stains human skin a reddish brown and causes a slight burning sensation, occasionally followed by slight blistering and exfoliation.
Pacific Science Association
Index to Volume 58