Pacific Science 56, no. 1
Dispersal, Mimicry, and Geographic Variation in Northern Melanesian Birds
Jared Diamond, pp. 1-22
Abstract: I present new information about 34 of the 195 resident land and freshwater bird species of northern Melanesia, an area characterized by a rich avifauna, high endemism, and great geographic variation in morphology. There are many examples of geographic variation in voice, behavior, habitat preference, altitudinal range, vertical stratum, abundance, and nest. Possible vocal convergence or mimicry between sympatric populations of different species is described between the goshawk Accipiter albogularis and the kingfisher Halcyon chloris, between the cuckoo-shrike Coracina [tenuirostris] and other species in its mixed-species foraging flocks, between the white-eyes Zosterops murphyi and Z. rendovae kulambangrae, and between the starlings Aplonis grandis and Mino dumontii. Hybridization is reported between the Bismarck and New Guinea races of the cuckoo Eudynamys scolopacea on Long Island (described as a new subspecies), between the whistlers Pachycephala pectoralis and P. melanura, and between the honey-eaters Myzomela tristrami and M. cardinalis. Cyclones bring Australian species, some of which occasionally remain to breed. Over-water dispersal ability varies greatly, from species that can be seen flying over water any day to species that rarely or never cross water. For instance, a channel 12 km long and only 0.15-1 km wide divides Florida Island into two halves, one of which possesses and the other of which lacks a resident population of the coucal Centropus milo.
Notes on Hawaiian Snake Eels (Pisces: Ophichthidae), with Comments on Ophichthus bonaparti
John E. McCosker, pp. 23-34
Abstract: The 22 ophichthid eel species of the Hawaiian Islands (including Johnston and the Northwestern Hawaiian Islands) are reviewed, and a key to their identification is provided. New Hawaiian records of Indo-Pacific species include Callechelys catostoma and Ophichthus bonaparti. Callechelys lutea is reported from Johnston Island. Hawaiian and Johnston Island ophichthid species comprise: Apterichtus flavicaudus, Brachysomophis crocodilinus, B. henshawi, Callechelys catostoma, C. lutea, Cirrhimuraena playfairii, Ichthyapus vulturis, Leiuranus semicinctus, Muraenichthys schultzei, Myrichthys colubrinus, M. magnificus, Ophichthus bonaparti, O. erabo, O. kunaloa, O. polyophthalmus, Phaenomonas cooperae, Phyllophichthus xenodontus, Schismorhynchus labialis, Schultzidia johnstonensis, Scolecenchelys cookei, S. gymnota, and S. puhioilo. Additional data are provided for the rare deep-water species Ophichthus kunaloa. The following synonymies are proposed: Ophisurus chrysospilos Bleeker, Poecilocephalus markworti Kaup, Ophichthys episcopus Castelnau, and Ophichthys garretti Günther = Ophichthus bonaparti (Kaup); and Ophichthus retifer Fowler = Ophichthus erabo (Jordan & Snyder). The endemism and distribution of Hawaiian and Johnston Island ophichthids (22.7%) are discussed and compared with those of muraenid eels. Vertebral formulas are provided for all species to facilitate the identification of leptocephali.
Reproductive Ecology of the Gobiid Fish Eviota abax at Nobeoka, Japan, with Notes on Geographic Variation
Masanori Taru and Tomoki Sunobe, pp. 35-40
Abstract: The reproductive behavior and spawning cycle of the gobiid fish Eviota abax were observed in a rocky tide pool at Nobeoka, Miyazaki, Japan. Both sexes maintained nonterritorial, overlapping home ranges. The spawnings took place at the low tide of neap to spring tidal periods. Matings varied in each spawning cycle, but males did not simultaneously mate with multiple females. Males were larger than females in the spawning pairs. After spawning, only the male guarded the egg mass. Although separated by 900 km, the basic patterns of reproductive ecology were similar at Nobeoka to those reported earlier for this species from Kominato, Chiba, Japan; nest entrances were smaller at Nobeoka than at Kominato, and larger males kept their home ranges longer at Nobeoka.
Reinstatement and Rediagnosis of Catapaguroides setosus and Description of a Second Hawaiian Species of the Genus (Decapoda: Anomura: Paguridea: Paguridae)
Patsy A. McLaughlin and Cory Pittman, pp. 41-48
Abstract: A species of the hermit crab genus Catapaguroides recently discovered in a sand-dwelling Halimeda community on the island of Maui, Hawaiian Islands, prompted a reexamination of the holotype of Catapaguroides setosus (Edmondson, 1951), described from off the south coast of O‘ahu. The latter species, currently considered a junior subjective synonym of Catapaguroides fragilis (Melin), is herein adjudged neither synonymous with C. fragilis nor conspecific with the second Hawaiian species. Catapaguroides setosus is reinstated with full specific rank, rediagnosed, and illustrated. The second species, Catapaguroides hooveri McLaughlin & Pittman, n. sp., is described and illustrated.
Predators of the Invasive Mussel Musculista senhousia (Mollusca: Mytilidae)
Jeffrey A. Crooks, pp. 49-56
Abstract: Musculista senhousia (Benson in Cantor, 1842) is a soft sediment–dwelling mussel that has spread anthropogenically from its native Asia to North America, Australasia, and Europe. This byssal mat-forming species can become overwhelmingly dominant and have dramatic impacts within invaded ecosystems, but its invasion may meet “ecological resistance” from native predators. In Mission Bay, San Diego, California, three fish species and two shorebirds were found to prey upon the mussel. Experimental results suggest that predation can dramatically impact intertidal mussel populations and may account for observed seasonal declines in the species. Despite the creation of a byssal cocoon, which may afford the mussel some protection, several taxa worldwide have been found to be Musculista predators. In addition, in areas where the mussel is native, humans impact mussel populations by gathering it for animal feed or bait, or to remove it from commercial shellfisheries grounds.
Redescription of the Indo-Pacific Scorpionfish Scorpaenopsis fowleri and Reallocation to the Genus Sebastapistes
John E. Randall and Stuart G. Poss, pp. 57-64
Abstract: The wide-ranging Indo-Pacific scorpionfish Scorpaenodes fowleri (Pietschmann), long placed in the genus Scorpaenopsis (largely because it lacks palatine teeth), is reclassified in the genus Sebastapistes. It is distinct from the species of Scorpaenopsis in several features: eye not extending above the dorsal profile of the head, large pores of the cephalic lateralis system, nasal pore above and adjacent to posterior nostril with a very small retrorse nasal spine (may be absent) on its upper edge, low ridgelike spines dorsally on the head, preocular spine usually embedded, sphenotic and postorbital spines absent or embedded; posterior lacrimal spine projecting slightly anteriorly, and a single spine posteriorly on the suborbital ridge with a pore-associated spine just below the ridge under the posterior third of the eye. Also significant is its very small size, the smallest of the Scorpaenidae (largest specimen, 37 mm SL; smallest mature female, 18 mm SL). The loss of palatine teeth appears to have occurred independently from the species of Scorpaenopsis. Sebastapistes fowleri is closest to S. strongia, the type species of the genus. In addition to having palatine teeth, S. strongia differs in the strongly retrorse posterior lacrimal spine and in having two spines on the suborbital ridge. The limits of Sebastapistes need reevaluation.
Abstract: Marine isotope stage (MIS) 11 may well represent one of the most significant interglacial highstand events of the past million years. Ocean volume changes charted from coastal exposures imply partial or complete melting of the some of the world’s major ice caps during a middle Pleistocene interglacial. The coastal geology of both Bermuda and the Bahamas yields evidence of an MIS 11 highstand 20 m higher than present. Further support for this catastrophic episode in sea-level history is revealed in subtidal and intertidal deposits at +28 +/- 2 m in O‘ahu, Hawai‘i. The stratigraphy, petrology, and uplift history of the Hawaiian deposits strongly suggest a correlation with MIS 11, and a compilation of amino acid racemization, uranium/thorium (alpha and mass spectrometry), and electron spin resonance ages shows a scatter between 300 and 550 kyr. When corrected for uplift, the Ka‘ena Highstand succession at Wai‘anae Health Center (OWH1) reveals a “stepping up” of sea level through the interglaciation, similar to that described in the Bahamas. Previous studies on O‘ahu attributed all 28 m elevation of the Ka‘ena Highstand to uplift since 0.5 Ma, but now it appears that only 8 m of that was caused by uplift, and the remaining 20 m by eustatic sea-level rise. These findings from O‘ahu strengthen evidence for the complete disintegration of the Greenland and West Antarctic ice sheets and partial melting of the East Antarctic ice sheet during the middle Pleistocene. If the instability of polar ice sheets can be linked to prolonged warm interglaciations as the data suggest, then existing conservative predictions for the magnitude of sea-level change by future “greenhouse” warming are seriously underestimated.
Pacific Science Association, pp. 101-105
Pacific Science 56, no. 2
Two New Species of Deep-Water Corallimorpharia (Cnidaria: Anthozoa) from the Northeast Pacific, Corallimorphus denhartogi and C. pilatus
Daphne G. Fautin, Tracy R. White, and Katherine E. Pearson, pp. 113-124
Abstract: Corallimorpharia is currently considered an order of hexacorallian anthozoans. Being skeletonless, its members are sometimes referred to as sea anemones, but they are morphologically more similar to members of Scleractinia than to members of Actiniaria. We describe two new species of corallimorpharians from deep water off the west coast of North America as Corallimorphus denhartogi, n. sp. and Corallimorphus pilatus, n. sp. The former occurs at depths of 2550-4300 m from Oregon to Baja California, and the latter at depths of 198-900 m from British Columbia to southernmost California. The average size of individuals of C. denhartogi is greater than that of C. pilatus, and tentacles of the latter are more densely arrayed and relatively longer than those of the former. The distribution and sizes of their cnidae distinguish them from one another as well as from their four congeners, which are widely distributed in the world’s oceans. In the collections we examined, specimens of C. denhartogi are more common than those of C. pilatus.
Ants of Tonga
James K. Wetterer, pp. 125-135
Abstract: This paper presents combined published, unpublished, and new ant records from 17 islands of Tonga representing all four island groups: Tongatapu (Tongatapu, ‘Eua, ‘Onevai, Pangaimotu), Ha‘apai (Lifuka, Kao, Tofua, ‘Uonukahahake, Nomuka, Nomuka-iki, Mango, Telekitonga), Vava‘u (Vava‘u, Nuapapu, Kapa), and the Niuas (Niuatoputapu, Niuafo‘ou). These records increase the list of ants known from Tonga to 53 species. Ten species, including six undescribed species, are local endemics found only in Tonga or only in Tonga and Samoa: Adelomyrmex sp., Camponotus conicus, Camponotus nigrifrons, Hypoponera sp., Monomorium sp., Ochetellus sp., Pheidole sp., Pristomyrmex sp., Strumigenys zakharovi, and Vollenhovia samoensis. Another 21 species are broadly distributed Pacific natives: Anochetus graeffei, Camponotus chloroticus, Hypoponera confinis, Monomorium liliuokalanii, Monomorium talpa, Odontomachus simillimus, Oligomyrmex atomus, Pheidole oceanica, Pheidole sexspinosa, Pheidole umbonata, Ponera incerta, Ponera tenuis, Pyramica dubia, Rogeria stigmatica, Solenopsis papuana, Strumigenys godeffroyi, Tapinoma minutum, Technomyrmex albipes, Tetramorium insolens, Tetramorium pacificum, and Tetramorium tonganum. Finally, 22 species are not native to the Pacific region, but were brought to the region by human commerce: Anoplolepis gracilipes, Cardiocondyla emeryi, Cardiocondyla nuda, Hypoponera opaciceps, Hypoponera punctatissima, Monomorium floricola, Monomorium pharaonis, Monomorium sechellense, Paratrechina bourbonica, Paratrechina longicornis, Paratrechina vaga, Pheidole fervens, Pheidole megacephala, Plagiolepis alluaudi, Pyramica membranifera, Solenopsis geminata, Strumigenys emmae, Strumigenys rogeri, Tapinoma melanocephalum, Tetramorium bicarinatum, Tetramorium lanuginosum, and Tetramorium simillimum. The number of ant species now known from Tonga is much as would be expected based on the species-area relationship for the neighboring island groups of Fiji, Wallis and Futuna, and Samoa. Differences in ant species richness among these island groups is primarily due to a greater number of local endemics in the island groups with greater land area.
The Nibbler Girella leonina and the Soldierfish Myripristis murdjan from Midway Atoll, First Records for the Hawaiian Islands
John E. Randall and G. Keoki Stender, pp. 137-141
Abstract: The girellid fish Girella leonina (Richardson) and the holocentrid Myripristis murdjan (Forsskal) are reported for the first time for the Hawaiian Islands from underwater photographs taken at Midway Atoll. Both species can be positively identified by the photographs.
The Land Snails of a Small Tropical Pacific Island, Aunu‘u, American Samoa
Robert H. Cowie and Rebecca J. Rundell, pp. 143-147
Abstract: Survey work on the American Samoan island of Aunu‘u, a small island off the eastern end of Tutuila, combined with review of museum collections, increased the known land snail fauna of the island from 2 to 22 species. Of these species, 12 are native to the Samoan Archipelago, nine are introduced, and one is cryptogenic (of unknown origin). The fauna is a subset of that of the main American Samoan island of Tutuila, although it also includes one species endemic to Aunu‘u but now extinct.
On Two Species of Kallymenia (Rhodophyta: Gigartinales: Kallymeniaceae) from the Hawaiian Islands, Central Pacific
Isabella A. Abbott and Karla J. McDermid, pp. 149-162
Abstract: Two species of Kallymenia from the Hawaiian Islands, one rare, K. sessilis Okamura, and the other described here for the first time, K. thompsonii, n. sp., are examined, compared, and contrasted with other similar Kallymenia species. Both species are unusual because Kallymenia is generally regarded as a temperate taxon, and tropical or subtropical species are seldom encountered. The two species are alike in that they have a female reproductive apparatus that is monocarpogonial: wherein a single carpogonial filament is associated with a supporting cell also bearing an arrangement of subsidiary cells that is characteristic of some of the family Kallymeniaceae. In the genus Kallymenia, vegetative components shown in a cross section are a narrow outer cortex, often only three cells thick, followed inwardly by one to two layers of subcortical cells. In the two species studied here, there appears to be a constant shape and arrangement of subcortical cells in each species, whereas the number of medullary filaments and their arrangements appear to be less stable in their configuration than the subcortical cells. Branched refractive cells or stellate cells, which often occur in species of Kallymenia, were not seen in K. thompsonii and only rarely in K. sessilis. Kallymenia thompsonii commonly has perforations in the maturing blades, whereas K. sessilis does not.
Reproduction in an Introduced Population of the Brown Anole, Anolis sagrei, from O‘ahu, Hawai‘i
Stephen R. Goldberg, Fred Kraus, and Charles R. Bursey, pp. 163-168
Abstract: The reproductive cycle of an introduced population of the brown anole, Anolis sagrei, from O‘ahu, Hawai‘i, was studied from a histological examination of monthly samples collected July 1999 to June 2000. Males undergo a seasonal testicular cycle in which all males > 37 mm snout-vent length are in spermiogenesis from January to August. Although some ovarian activity was found in all months, the period of greatest ovarian inactivity was October-December, which corresponds to the time of male gonadal regression. The reproductive cycle of A. sagrei in Hawai‘i resembles that of populations in Belize, Florida, and Jamaica, where minimum gonadal activity was recorded from November through February. Body sizes at reproductive maturity were similar in all four localities. Anolis sagrei in Hawai‘i has an ovarian cycle typical of other Anolis lizards with a prolonged breeding season and production of single eggs in succession. Because A. sagrei has been in Hawai‘i for only approximately 20 yr, sufficient time has not elapsed to allow evolution of its reproductive cycles, but this study presents baseline reproductive data that can be used for future studies to see if the A. sagrei reproductive cycles are modified as the lizards adapt to the environmental conditions of their newly colonized range.
Mixed Siliciclastic-Skeletal Carbonate Lagoon Sediments from a High Volcanic Island, Viti Levu, Fiji, Southwest Pacific
Oliver A. Gussmann and Abigail M. Smith, pp. 169-189
Abstract: Modern sedimentation in the Navua-Suva Lagoon, southeastern Viti Levu, Fiji, derives from both allochthonous siliciclastics and autochthonous marine carbonates. Sediments are characterized by a high insoluble load, small grain size, a wide range of textures, and a high degree of mixing. The distribution of the two facies (skeletal-dominated muddy sandy gravel and skeletal-bearing very fine sand to mud) is controlled by both the shallow-marine carbonate sediment productivity and sediment supply and dispersal processes from siliciclastic point sources across a narrow lagoon. Mollusks and Halimeda dominate the gravel fraction of the skeletal grains. Sediment budget estimates indicate that 97% of the siliciclastic supply bypasses the lagoon. Some 0.2 Mt/yr is accumulating in the lagoon, not yet enough to inhibit potential carbonate production (~0.1 Mt/yr) by a interreefal benthos that is at least somewhat sediment-tolerant. Contemporary allochthonous siliciclastic and autochthonous skeletal carbonate sedimentation in the lagoon results in true syndepositional (in situ) mixing. The central high volcanic island mass in a tropical setting produces the geomorphological (high topographic relief, narrow shelf), environmental (high rainfall), and ecological (shallow benthic area) conditions that lead to carbonate-siliciclastic mixing in lagoons along adjacent, mostly carbonate, coasts of oceanic islands, a high volcanic island mass effect. We propose that tropical in situ mixing of carbonate and siliciclastic sediments is more common in high volcanic island settings than previously appreciated. Such islands are thus excellent testing grounds for the study of carbonate-siliciclastic interactions. Their special characteristics highlight the need for better understanding of coastal physical processes of tropical Pacific high volcanic islands.
Nonindigenous Species Introductions on Coral Reefs: A Need for Information
S. L. Coles and L. G. Eldredge, pp. 191-209
Abstract: Nonindigenous species invasions have caused disruptions of native communities and detrimental economic impacts to fisheries in many temperate marine areas. However, comparatively little information exists for tropical regions, and even less is known about occurrences and impacts of nonindigenous species on coral reefs. Studies in the Tropics to date have mostly been limited to surveys in harbors and ports where corals and reef organisms are usually missing or rare and environmental conditions are usually quite different from those found on coral reefs. The few studies available for coral reefs suggest that nonindigenous species are thus far a relatively minor component of the total biota, but some species, especially introduced red algae, can be invasive and dominate reef areas. With limited information available, there is a need for studies of the occurrence and impacts of nonindigenous species that are focused on coral reef environments. This review summarizes the information for nonindigenous species from harbors, embayments, and coral reef surveys in the tropical Pacific and outlines procedures for studies to detect species introductions.
Hawaiian Marine Bioinvasions: A Preliminary Assessment
L. G. Eldredge and J. T. Carlton, pp. 211-212
Abstract: Through the Hawaii Biological Survey at Bishop Museum, a count of the total numbers of species in the Hawaiian Archipelago has been accumulated, with the latest listing (1999) totalling 23,150, of which 5047 are nonindigenous species. For the nonindigenous marine and estuarine species, we have been accumulating information from the literature, museum specimens, and through field collections. This preliminary assessment is an extended abstract of a much longer review still in preparation.
Distribution and Biodiversity of Australian Tropical Marine Bioinvasions
Chad L. Hewitt, pp. 213-222
Abstract: Marine invasions have been identified in virtually all regions of the world, yet relatively few introductions have been detected in the Tropics. This has been attributed at least in part to an increase in intrinsic native community resistance at lower latitudes resulting from strongly interacting food webs in high(er) diversity systems. However, recent evidence from surveys in Australia and elsewhere indicate that tropical systems are also susceptible to invasions, though detection ability may be constrained by taxonomic limitations. Preliminary analyses of data from surveys designed to detect introduced species do not support a pattern of decreased invasion success in higher diversity systems but do indicate a strong latitudinal gradient at the mesoscale of Australia. This cannot be attributed to disparities in search effort (controlled for by consistency in survey effort) or taxonomic knowledge. The original hypothesis of a decreased relative susceptibility of tropical versus temperate biota to invasions may remain viable, but may be scale dependent. Additional confounding factors may include differing vector strengths and availability of source bioregions.
Species Introductions and Potential for Marine Pest Invasions into Tropical Marine Communities, with Special Reference to the Indo-Pacific
P. A. Hutchings, R. W. Hilliard, and S. L. Coles, pp. 223-233
Abstract: Introductions of marine species by hull fouling or ballast water have occurred extensively in temperate areas, often with substantial deleterious impacts. However, current information suggests that marine introductions potentially able to achieve pest species status have been fewer in tropical regions. A 1997 risk assessment examining introductions to 12 tropical ports in Queensland (Australia) concluded that far fewer marine species appeared to have been introduced, even at major bulk export ports where the number of ship visits and volume of discharged ballast water are more than at most of Australia’s cooler water ports. Results from recent surveys looking for introduced species in tropical ports across northern Australia are beginning to support this conclusion, although the lack of historic baseline surveys and the poor taxonomic status of many tropical groups are preventing a precise picture. The 1997 report also concluded that, apart from pathogens and parasites of warm-water species, the potential for marine pest invasions in Queensland tropical ports appeared to be low, and not only because much of the discharged ballast water originates from temperate ports in North Asia. In contrast, recent surveys of harbors in Hawai‘i have found over 110 introduced species (including 23 cryptogenic species), the majority in the estuarine embayments of Pearl Harbor and O‘ahu’s commercial harbors. We suggest that the biogeographically isolated and less diverse marine communities of Hawaiian ports have been more susceptible to introductions than those of tropical Australia for several reasons, including the closeness of Australia to the central Indo-Pacific “triangle” of megadiversity (Indonesia-Philippines-Papua New Guinea) and consequent high biodiversity and low endemicity, hence offering fewer niches for nonindigenous species to become established. The isolated central Pacific position of Hawai‘i and its long history of receiving worldwide commercial and naval shipping (including more heavily fouled vessels than contemporary merchant ships) is another key factor, although the estuarine warm-water ports of Townsville, Brisbane, and Darwin also provided anchorages for military units during World War II. Hull fouling remains an important vector, as it is the most likely cause of the recent transfer of the highly invasive Caribbean black-striped mussel (Mytilopsis sallei) to enclosed (lock-gate) marinas in Darwin by international cruising yachts arriving via the Panama Canal. The cost of eliminating this pest (>US$1.6 million) underscores the importance of managing not just commercial shipping but also pleasure craft, fishing boats, and naval ships as vectors of exotic species to ports, harbors, and marinas in coral reef areas.
Do Locals Rule? Interactions between Native Intertidal Animals and a Caribbean Barnacle in Hawai‘i
Chela Zabin and Michael G. Hadfield, pp. 235-236
Abstract: Interactions between Chthamalus proteus and two native Hawaiian species, the barnacle Nesochthamalus intertextus and the pulmonate limpet Siphonaria normalis, were examined. (Extended abstract.)
Pacific Science Association, pp. 237-240
Pacific Science 56, no. 3
Aseraggodes holcomi, a New Sole (Pleuronectiformes: Soleidae) from the Hawaiian Islands
John E. Randall, pp. 247-253
Abstract: The soleid fish Aseraggodes holcomi, the third Hawaiian species of the genus, is described from six specimens collected off O‘ahu, from sand in 0.6-27 m. It is distinct in having 68-72 dorsal-fin rays, 47-50 anal-fin rays, 76-80 lateral-line scales, the snout not overlapping the lower lip, and in its small size (largest, 58.6 mm SL, a mature female).
Inking in a Blue-ringed Octopus, Hapalochlaena lunulata, with a Vestigial Ink Sac
Christine L. Huffard and R. L. Caldwell, pp. 255-257
Abstract: Here we report for the first time that adult Hapalochlaena lunulata (Quoy & Gaimard, 1832), which has a vestigial ink sac, is capable of inking. Ink was released under three different agonistic conditions: female-female aggression, rejection of mating attempt, and when attacked by a predator. We observed no apparent reaction to the ink by the other animals involved in these interactions.
New Host and Ocean Records for the Parasitic Copepod Bobkabata kabatabobbus (Lernaeosoleidae: Poecilostomatoida)
George W. Benz, Kazuya Nagasawa, and Jeremy Wetmore, pp. 259-262
Abstract: The parasitic copepod Bobkabata kabatabobbus Hogans & Benz is reported for the first time from the Pacific Ocean and from the darkfin sculpin, Malacocottus zonurus (Psychrolutidae: Scorpaeniformes). Based on five specimens, several morphological features are reported for the first time for B. kabatabobbus, including a second protuberance on the cephalothorax, a pair of vestigial legs on the neck, and two dark-staining sclerites on the trunk that may represent body segment boundaries or interpodal bars.
The Vegetation of Robinson Crusoe Island (Isla Masatierra), Juan Fernandez Archipelago, Chile
Josef Greimler, Patricio Lopez S., Tod F. Stuessy, and Thomas Dirnbock, pp. 263-284
Abstract: Robinson Crusoe Island of the Juan Fernandez Archipelago, as is the case with many oceanic islands, has experienced strong human disturbances through exploitation of resources and introduction of alien biota. To understand these impacts and for purposes of diversity and resource management, an accurate assessment of the composition and structure of plant communities was made. We analyzed the vegetation with 106 releves (vegetation records) and subsequent Twinspan ordination and produced a detailed colored map at 1:30,000. The resultant map units are (1) endemic upper montane forest, (2) endemic lower montane forest, (3) Ugni molinae shrubland, (4) Rubus ulmifolius-Aristotelia chilensis shrubland, (5) fern assemblages, (6) Libertia chilensis assemblage, (7) Acaena argentea assemblage, (8) native grassland, (9) weed assemblages, (10) tall ruderals, and (11) cultivated Eucalyptus, Cupressus, and Pinus. Mosaic patterns consisting of several communities are recognized as mixed units: (12) combined upper and lower montane endemic forest with aliens, (13) scattered native vegetation among rocks at higher elevations, (14) scattered grassland and weeds among rocks at lower elevations, and (15) grassland with Acaena argentea. Two categories are included that are not vegetation units: (16) rocks and eroded areas, and (17) settlement and airfield. Endemic forests at lower elevations and in drier zones of the island are under strong pressure from three woody species, Aristotelia chilensis, Rubus ulmifolius, and Ugni molinae. The latter invades native forests by ascending dry slopes and ridges. It successfully outcompetes endemic taxa, including its congener Ugni selkirkii. The aggressive herb Acaena argentea severely threatens to overtake native grassland.
Reproductive Phenology of Pterocladiella capillacea (Rhodophyta: Gelidiales) from Southern Baja California, Mexico
Elisa Serviere-Zaragoza and Ricardo Scrosati, pp. 285-290
Abstract: Abundance of vegetative and reproductive fronds of Pterocladiella capillacea (Gelidiaceae) from an intertidal population at Lobos Point, on the Pacific coast of southern Baja California, Mexico, was measured bimonthly between March 1998 and January 1999. Fronds with tetrasporic sori occurred throughout the year, although in low percentages with respect to the total amount of fronds: monthly means ranged between 0.5% (May) and 6.0% (July). Fronds with cystocarps and fronds with spermatangia were found only in January, with even lower percentages: 0.15% and 0.10%, respectively. The overall predominance of reproductive tetrasporophytic fronds over reproductive gametophytic fronds is common in natural populations of the Gelidiaceae. Reproductive phenology, however, varies widely within this family, even within the same species, as is the case for P. capillacea. Little is known about factors affecting the reproductive phenology of this cosmopolitan alga; field and laboratory studies are needed to provide a reliable predictive framework.
Nonindigenous Ascidians in Tropical Waters
Gretchen Lambert, pp. 291-298
Abstract: Ascidians (invertebrate chordates) are abundant in many ports around the world. Most of them are nonindigenous species that tolerate wide fluctuations in temperature, salinity, and even pollution. These sessile suspension feeders have a rapid growth rate, usually a short life span of a few months, reach sexual maturity when only a few weeks old, and produce large numbers of short-lived nonfeeding planktonic larvae. They thrive on marina floats, pilings, buoys, and boat bottoms in protected harbors where there is reduced wave action and enhanced nutrients from anthropogenic activities. Nonindigenous ascidians frequently overgrow oysters and mussels, which are often cultivated in or near busy harbors. Adult ascidians on ship or barge hulls may survive transport over thousands of kilometers to harbors with conditions similar to those they left; occasionally live larvae have also been recovered from ships’ ballast water. U.S. Navy dry dock movements between major Pacific ports have transported large masses of fouling nonindigenous taxa, including ascidians. Transfer between culture sites of oysters, mussels, and associated lines and nets may provide an additional mode of transport. Once nonindigenous ascidians become established, they provide large local sources of larvae for further possible invasions into additional harbors and nearby natural marine communities. Invasive species include both solitary and colonial forms, with a preponderance of large solitary species that thrive in highly disturbed habitats. In Guam, for example, most nonindigenous ascidians are confined to harbor structures and have not as yet significantly colonized natural reefs. In contrast, healthy natural benthic regions both inside and outside the harbors of Guam are usually stable coral reef communities containing a high diversity, but very low biomass, of native colonial ascidian species. However, in several areas of the Caribbean a native colonial didemnid has recently begun overgrowing coral reefs. In the Gulf of Mexico a nonindigenous didemnid now covers many offshore oil rigs and may become a threat to neighboring natural reefs. Additional data on nonindigenous ascidians in Australia, Palau, Hawai‘i, and the Mediterranean are included. Although serious invasion of coral reefs has not yet been reported, more studies and regular monitoring are needed.
Distribution and Reproductive Characteristics of Nonindigenous and Invasive Marine Algae in the Hawaiian Islands
Jennifer E. Smith, Cynthia L. Hunter, and Celia M. Smith, pp. 299-315
Abstract: Quantitative and qualitative surveys were conducted on five of the main Hawaiian Islands to determine the current distribution of nonindigenous algae and to assess the level of impact that these algal species pose to Hawai‘i’s marine ecosystems. Maps were generated to examine the spread of these organisms from initial sites of introduction and to assimilate information regarding habitat characteristics that appear to make some sites more susceptible to invasion than others. Blooms of native invasive algae were also documented when encountered. The potential for vegetative propagation via fragmentation was examined experimentally as a mode of reproduction for four of the most common species of nonindigenous algae in Hawai‘i. This research has demonstrated that each of these algal species currently has a distinctive distribution and reproductive strategies appear to vary among species. More research is needed to further understand the competitive strategies and unique ecological characteristics that allow these nonindigenous species to become highly successful in the Hawaiian Islands.
Abstract: Observations on the temporal occurrence of copulating pairs, ovigerous females, monthly brooding periods, and embryo development stages in Pilumnus vespertilio Fabricius were carried out in the wild on Okinawa Island, Japan. The relationship between the female gonad and hepatopancreas during a reproductive period was also studied. These reproductive activities were observed in relation to the lunar cycles. An inverse relationship between mass of the hepatopancreas and development of the gonad was observed. Mating and breeding activities were perfectly synchronized with the lunar periodicity. Five broods from May to September were observed in a single breeding period, and the average brooding period was 21.2 days with an interlude of 8.5 +/- 3.1 days between broods/months. The shortest interlude was between May and June (4 days). A sixth brood that started in October was not followed to the end because it started with very few ovigerous females. Embryo development time in days decreased with each stage and averaged 5.3 days per stage. Copulating activity and appearance of ovigerous females during successive broods (months) were clearly synchronized with the lunar cycle. Although copulating frequency was highest after the full moon, nearly 100% of females were ovigerous around the new moon. All females of any one sample carried eggs of the same development stage. All females released their larvae 1-3 days before full moon, coinciding with a high tide. Larvae are probably released during this time as a survival strategy against predators such as planktivorous fish and against adverse intertidal conditions during other times.
Influence of Hydrologic Processes on Reproduction of the Introduced Bivalve Potamocorbula amurensis in Northern San Francisco Bay, California
Francis Parchaso and Janet K. Thompson, pp. 329-345
Abstract: Monthly censusing of reproductive condition of the Asian clam Potamocorbula amurensis at four sites in northern San Francisco Bay over a 9-yr period revealed year-to-year differences in local reproductive activity that are associated with patterns of hydrologic variability. Between 1989 and 1992, Northern California experienced a drought, whereas the period between 1993 and 1998 was marked by a mix of wet and dry years. We took advantage of the extreme year-to-year differences to examine reproductive responses to river inflow patterns. Populations of P. amurensis at the upstream sites in Suisun Bay and Carquinez Strait were more reproductively active during wet years than dry years. Conversely, at the downstream site in San Pablo Bay, the population was more reproductively active during dry years than wet years. We suggest that the different reproductive patterns observed reflect the clam’s response to different sources of food. During wet years, organic matter from the rivers augments food supplies in Suisun Bay. During dry years, when inflow into the San Francisco Bay Estuary from the rivers is reduced, water transported from the adjacent ocean into the estuary as far as San Pablo Bay provides a supplemental food supply for the local production. The populations take advantage of these spatially distinct food supplies by initiating and maintaining local reproductive activity. We conclude that the ability of P. amurensis to consume and use various types of food to regulate its reproductive activity is part of the reason for its success as an invasive species.
Two Genetically Distinct Populations of Bobtail Squid, Euprymna scolopes, Exist on the Island of O‘ahu
J. R. Kimbell, M. J. McFall-Ngai, and G. K. Roderick, pp. 347-355
Abstract: Population structure of the endemic Hawaiian bobtail squid, Euprymna scolopes, was examined using both morphological and genetic data. Although allozyme polymorphism was negligible, measurements of eggs, juveniles, and adults, as well as genetic data sequences of mitochondrial cytochrome oxidase I, demonstrated highly significant population structuring between two populations found on the northeastern and southern coasts of the island of O‘ahu. These data suggest that extremely low levels of gene flow occur among these populations. Population subdivision of marine shallow-water invertebrates in Hawai‘i is not expected based on earlier surveys, but may reflect a more general pattern for organisms, both marine and terrestrial, that exhibit limited dispersal. The subdivision also provides insight into the pathway through which coevolution between E. scolopes and its internal symbiont, Vibrio fischeri, may proceed.
Pacific Science Association, pp. 357-360
Pacific Science 56, no. 4
Introduction and Distributional Expansion of Trechus obtusus (Coleoptera: Carabidae) in Maui, Hawai‘i
James K. Liebherr, and Raina Takumi, pp. 365-375
Abstract: Trechus obtusus Erichson (tribe Trechini), native to Europe and North Africa and introduced to the Pacific coast of North America, is recorded for the first time from East Maui Island, Hawai‘i, based on collections made at Haleakala National Park in September 1998. The species subsequently expanded its distribution to include Polipoli Springs State Recreation Area, East Maui. Range expansion has averaged 3 km per year, based on documented absence of T. obtusus from the Polipoli Springs area in 1998. All Hawaiian individuals are macropterous, even though European and North American populations of T. obtusus are dimorphic for wing configuration, with the brachypterous form most common in long-established populations. The source area for the Hawaiian invasion is hypothesized to be Oregon or the San Francisco Bay area, based on the closest match in the frequency of macroptery between specimens from Hawai‘i and those from those mainland areas. Monomorphic macroptery of the Hawaiian populations suggests that the founder population was small, with estimates ranging from as few as 6 individuals to as many as 25, assuming the founding propagule was drawn at random from populations in the western United States. Baseline abundance data are presented for Polipoli Springs State Recreation Area, where T. obtusus co-occurs with seven native Mecyclothorax species (tribe Psydrini), establishing the opportunity for long-term assessment of the impact of the introduced species on the sympatric native fauna. Means to identify T. obtusus in the context of the Hawaiian carabid beetle fauna are presented.
Brown Root Rot Disease in American Samoa’s Tropical Rain Forests
Fred E. Brooks, pp. 377-387
Abstract: Phellinus noxius (Corner) Cunningham causes root and lower stem rot of woody plants throughout the South Pacific region. Its hosts include rubber, mahogany, cacao, and many timber, fruit, and landscape trees. Though endemic to the Tropics, no reports were found describing brown root rot disease in native forests, exclusively. Incidence, distribution, and host range of P. noxius were measured in primary and secondary rain forests on Tutuila Island, American Samoa. Phellinus noxius was recorded in 19 of 20 strip transects and 1.2-ha established plots and in all vegetation types, infecting 37 tree species in 30 genera and 22 families. Species most affected were Myristica fatua, Dysoxylum samoense, and Hibiscus tiliaceus—25, 16, and 10%, respectively. Of 62 infection centers, 33 contained the same tree species and 13 were dominated by a single species. The fewest infections were recorded at primary montane and ridge top sites. Regenerating secondary valley sites had the highest incidence of disease and greatest number of infection centers. Infection centers at these disturbed sites also contained more trees on average than centers at primary sites. Disease incidence was influenced more by human disturbance than by vegetation type, topography, stem diameter, stem density, or soil type. The disturbed sites also appeared to lack the species richness of mature sites. This agrees with other host/pathogen associations, such as Douglas-fir/P. weirii and hardwood/P. noxius plantations, where disease incidence and spread was higher in species-poor than in species-rich stands.
Review of the Hawaiian Razorfishes of the Genus Iniistius (Perciformes: Labridae)
John E. Randall and John L. Earle, pp. 389-402
Abstract: The Indo-Pacific labrid fishes of the genus Xyrichtys Cuvier, popularly referred to as razorfishes, are reclassified in Iniistius Gill. The razorfishes of the Atlantic and eastern Pacific currently placed in Xyrichtys remain in that genus except for the Indo-Pacific Iniistius pavo Valenciennes, which also ranges to the eastern Pacific. The Indo-Pacific Novaculichthys woodi Jenkins, sometimes classified in Novaculops, is shifted to Xyrichtys. Five species of razorfishes of the genus Iniistius are recognized for the Hawaiian Islands: the wide-ranging Indo-Pacific I. aneitensis (Günther), I. baldwini (Jordan & Evermann), I. pavo, the endemic I. umbrilatus (Jenkins), and I. celebicus (Bleeker), a new record for Hawai‘i (otherwise known in the western Pacific from the Mariana Islands, Marshall Islands, and American Samoa). Hemipteronotus evides Jordan & Richardson is a synonym of I. baldwini. Iniistius niger (Steindachner) is a melanistic color phase of I. pavo.
Anthropogenic Biotic Interchange in a Coral Reef Ecosystem: A Case Study from Guam
Gustav Paulay, Lisa Kirkendale, Gretchen Lambert, and Chris Meyer, pp. 403-422
Abstract: Guam is the administrative and economic hub of Micronesia, hosts one of the largest U.S. military bases in the Pacific, and lies at the crossroads among Pacific islands, the United States, and Asia. Although terrestrial introductions, exemplified by the brown tree snake, have received much attention, marine introductions have been little studied until now. We have documented a diverse assemblage of marine species brought to Guam by human-mediated transport: a few intentionally, most unintentionally. Sessile species dominate the nonindigenous biota. Because of Guam’s tourism-based economy, ballast water is not a major source of introductions, but ship’s hulls have brought many invaders. A study of the fauna associated with two dry docks demonstrates the large impact of such structures, moved slowly from harbor to harbor after long residence times. The majority of nonindigenous species have remained confined to artificial substrata in the harbor, but some have invaded adjacent coral reef habitats and spread islandwide. Although several nonindigenous species are now well established, major impacts to reefs on Guam remain to be identified. Space on reefs is vastly dominated by indigenous species; in contrast artificial substrata often have an abundance of nonindigenous species.
Mycorrhizal Status of Two Hawaiian Plant Species (Asteraceae) in a Tropical Alpine Habitat: The Threatened Haleakala Silversword (Argyroxiphium sandwicense subsp. macrocephalum) and the Endemic Dubautia menziesii
R. E. Koske and J. N. Gemma, pp. 423-430
Abstract: Samples of roots and root-zone soil from the threatened species Argyroxiphium sandwicense subsp. macrocephalum and the endemic species Dubautia menziesii, both members of the Asteraceae, were collected in a tropical alpine area in Haleakal_ National Park, Maui, Hawai‘i, and examined for arbuscular mycorrhizal fungi (AMF). All root samples exhibited the Paris-type of mycorrhizae with arbuscules produced on hyphal coils, and all soil collections included spores of AMF. Spores of Acaulospora, Entrophospora, Glomus, and Scutellospora spp. were recovered from this site.
Watershed-Scale Comparisons of Algal Biodiversity in High-Quality Proximate Hawaiian Stream Ecosystems
Alison R. Sherwood and Michael H. Kido, pp. 431-440
Abstract: The stream macroalgal floras of two proximate, high-quality stream valleys (Hanakapi‘ai and Limahuli) located on the northern quadrant of the Hawaiian island of Kaua‘i were inventoried and compared on a watershed scale, providing interesting insight into Hawai‘i’s potential taxonomic diversity and the influential role played by physical factors in shaping community characteristics. A total of 26 species of macroalgae (five Cyanophyta, 18 Chlorophyta, one Rhodophyta, and two Chromophyta) was identified, of which only eight were common to both streams. Chlorophyta composed the majority of macroalgal taxa identified (63.2% in Hanakapi‘ai Stream and 66.7% in Limahuli Stream). Three macroalgal species are new records for Hawai‘i and one (Chamaesiphon curvatus var. elongatum Nordst.) is a Hawaiian endemic. Significant differences in the macroalgal densities between Hanakapi‘ai and Limahuli Streams (Chlorophyta versus Chromophyta, respectively) were attributed to measured differences in riparian canopy cover (34.8% versus 70.0% closed, respectively). Significantly lower densities of macroalgal species in riffle-run habitats in Hanakapi‘ai as compared with Limahuli Stream were potentially explainable by “top-down” control by robust populations of native herbivorous fish species.
Mass Oviposition and Egg Development of the Ocean-Skater Halobates sobrinus (Heteroptera: Gerridae)
Lanna Cheng and Robert L. Pitman, pp. 441-445
Abstract: We report the first observation of mass oviposition by the ocean-skater Halobates sobrinus White in the eastern tropical Pacific Ocean. We netted, in one scoop, 833 insects and a single egg mass with an estimated 70,000 eggs on a plastic gallon (3.785-liter) milk jug. Evidently anthropogenic debris could provide potentially important oviposition substrates for Halobates spp. in the open ocean. Freshly laid eggs incubated at 26–32° C hatched within 8–10 days. Eggs kept at temperatures below 22° C did not hatch even after 20 days.
Rough-Toothed Dolphins (Steno bredanensis) as Predators of Mahimahi (Coryphaena hippurus)
Robert L. Pitman and Charles Stinchcomb, pp. 447-450
Abstract: We present details of four separate observations of rough-toothed dolphins (Steno bredanensis) apparently preying on adult-sized (>1 m) mahimahi (Coryphaena hippurus) in the eastern Pacific. We cite similar sightings from Hawai‘i and some additional behavioral observations (synchronized swimming, food sharing, regular association with flotsam), and suggest that rough-toothed dolphins may be specialized predators on large mahimahi.
Comparison of Managed and Unmanaged Wedge-Tailed Shearwater Colonies on Oahu: Effects of Predation
David G. Smith, John T. Polhemus, and Eric A. VanderWerf, pp. 451-457
Abstract: On O‘ahu, Wedge-tailed Shearwaters (Puffinus pacificus) and other seabirds nest primarily on small offshore islets, but fossil evidence shows that many seabirds formerly bred on O‘ahu itself. Predation by introduced mammals is suspected to be the primary factor preventing shearwaters and other seabirds from reestablishing large nesting colonies on O‘ahu. We investigated the effects of predation on Wedge-tailed Shearwaters by comparing three small unmanaged colonies at Malaekahana State Recreation Area on O‘ahu, where feral cats are fed by the public, with a large managed colony at nearby Moku‘auia Island State Seabird Sanctuary, where predators are absent. During three visits on 19 April, 16 June, and 23 October 2000, we located 69 occupied burrows in three colonies at Malaekahana and 85 occupied burrows in four monitoring plots at Moku‘auia. Many more nests produced chicks at Moku‘auia (62%) than at Malaekahana (20%). Among plots at Malaekahana, reproductive success was lowest (zero) at the colony closest to the cat feeding site. In addition, 44 adult shearwater carcasses were found at Malaekahana near the cat feeding site. Predation, most likely by cats attracted to supplemental food, had a devastating impact on shearwaters at Malaekahana. At one colony there was complete reproductive failure and almost all adults were killed. Populations of long-lived species like seabirds are sensitive to adult mortality, and Malaekahana may act as a sink, draining birds away from other areas.
Polychaetes Associated with a Tropical Ocean Outfall; Synthesis of a Biomonitoring Program off O‘ahu, Hawai‘i
J. H. Bailey-Brock, B. Paavo, B. M. Barrett, and J. Dreyer, pp. 459-479
Abstract: A comparison of benthic polychaete communities off the Sand Island Wastewater Outfall was undertaken to recognize organic enrichment indicator species for Hawaiian waters. Primary-treatment sewage is discharged off the south shore of O‘ahu at 70 m depth. A historical data set spanning 9 yr for seven sites at 70 m and two recent studies at 20, 50, and 100 m depths were analyzed. Geochemical data did not support the assumption that the outfall is an important source of organic enrichment in nutrient-poor sandy sediments within oligotrophic tropical waters. Five polychaete species, however, appeared particularly sensitive, positively or negatively, to environmental conditions near the outfall. Neanthes arenaceodentata (Nereididae) and Ophryotrocha adherens (Dorvilleidae) have been dominant at sites within the outfall’s zone of initial dilution (ZID). Since 1993, N. arenaceodentata has virtually disappeared, and O. adherens concurrently became abundant and continued to flourish at ZID sites. Well-known indicators within the Capitella capitata complex (Capitellidae) were present at ZID and control (far field) sites though their ZID abundance was greater. Two sabellids, Euchone sp. B and Augeneriella dubia were inversely distributed, the smaller Euchone sp. B at far field sites and larger A. dubia within ZID stations. The former was most likely restricted to a greater proportion of fine sediment particles at two far field sites. The most abundant and widespread polychaete off O‘ahu’s south shore was Pionosyllis heterocirrata (Syllidae), which does not seem to represent a sensitive indicator species. Ophryotrocha adherens was the most abundant indicator species within the ZID; P. heterocirrata was the most ubiquitous species at all sites and should always be expected in these sediments. Traditional measurements of numerical abundance, species richness, and diversity (H’) have not shown a clear distinction between ZID and far field sites in annual analyses. An examination of composited data over an 11-yr period does support such a distinction. Multidimensional scaling (MDS) analyses clearly delineate different assemblages. We suggest that MDS analyses are sensitive to the community differences present near the outfall. The ZID community is clearly contained within the Environmental Protection Agency–approved ZID boundary. Because each ZID and far field site supports a diverse and coarsely similar polychaete fauna, no pollution level effects seem to be present.
Pacific Science Assocation, pp. 481-486