Ishigaki Island Research Articles

Spatial and temporal distribution of Pu in the Northwest Pacific Ocean using modern coral archives

Historical 239Pu activity concentrations and 240Pu/239Pu atom ratios were determined in skeletons of dated modern corals collected from three locations (Chuuk Lagoon, Ishigaki Island and Iki Island) to identify spatial and temporal variations in Pu inputs to the Northwest Pacific Ocean. The main Pu source in the Northwest Pacific is fallout from atmospheric nuclear weapons testing which consists of global fallout and close-in fallout from the former US Pacific Proving Grounds (PPG) in the Marshall Islands. PPG close-in fallout dominated the Pu input in the 1950s, as was observed with higher 240Pu/239Pu atom ratios (>0.30) at the Ishigaki site. Specific fallout Pu contamination from the Nagasaki atomic bomb and the Ivy Mike thermonuclear detonation at the PPG were identified at Ishigaki Island from the 240Pu/239Pu atom ratios of 0.07 and 0.46, respectively. During the 1960s and 1970s, global fallout was the major Pu source to the Northwest Pacific with over 60% contribution to the total Pu. After the cessation of the atmospheric nuclear tests, the PPG again dominated the Pu input due to the continuous transport of remobilised Pu from the Marshall Islands along the North Equatorial Current and the subsequent Kuroshio Current. The Pu contributions from the PPG in recent coral bands (1984 onwards) varied over time with average estimated PPG contributions between 54% and 72% depending on location.

Presence of allochronic populations of the white grub beetle Dasylepida ishigakiensis (Coleoptera: Scarabaeidae) on Ishigaki Island, Japan

To investigate the seasonal prevalence of Dasylepida ishigakiensis Niijima et Kinoshita (Coleoptera: Scarabaeidae), synthetic sex pheromone traps were placed on Ishigaki Island in 2008 and 2009. One population is known to occur in the forest and fly for mating from early March to early April. The trap data revealed a second population in the farmland that flew for mating much earlier (mid-January to late February) than did the other population, indicating the presence of allochronic populations. Adults of the farmland population were caught throughout the sugarcane-grown area on the island, whereas those of the forest population appeared to be limited to the forest area. The temporal pattern of trap catches of each population was generally the same between 2008 and 2009. Relatively large trap catches were observed in the west central plane area and a small northern area of the northeastern peninsula of the island. These results suggest that, although it has not caused any damage to agricultural crops on this island, this beetle might be a potentially serious pest of sugarcane crops in the future, as reported on another island of Okinawa.

Population genetic structure and implications for natal philopatry of nesting green turtles Chelonia mydas in the Yaeyama Islands, Japan

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 14:141-148 (2011) - DOI: https://doi.org/10.3354/esr00355 Population genetic structure and implications for natal philopatry of nesting green turtles Chelonia mydas in the Yaeyama Islands, Japan Hideaki Nishizawa1,*, Osamu Abe2, Junichi Okuyama1, Masato Kobayashi2, Nobuaki Arai1 1Graduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto, 606-8501, Japan 2Ishigaki Tropical Station, Seikai National Fisheries Research Institute, Fisheries Research Agency, Fukaiohta 148-446, Ishigaki, Okinawa 907-0451, Japan *Email: nishizawa0311@gmail.com ABSTRACT: Patterns of mitochondrial DNA (mtDNA) variation and microsatellite genotyping were used to analyze the population genetic structure of nesting green turtles Chelonia mydas (n = 67) in the Yaeyama Islands of Japan, which represent the northern limit of green turtle nesting in the western Pacific Ocean. The composition of a mixture of 6 mtDNA haplotypes from 3 rookeries, southwestern (SW) Iriomote Island (n = 26), eastern (E) Ishigaki Island (n = 29), and northwestern (NW) Ishigaki Island (n = 12), produced genetic diversity values (haplotype diversity h = 0.582 to 0.638, nucleotide diversity π = 0.0138 to 0.0244) within the high end of the range found in previous studies. The phylogeny of haplotypes, representing 3 distinct clades, indicated historical introgressions by individuals with divergent haplotypes from both Pacific colonies and Indian and Southeast Asian colonies. Significant genetic differentiation, at least between SW Iriomote Island and Ishigaki Island in which samples from E and NW Ishigaki were combined, was observed based on mtDNA; this indicated precise female natal philopatry compared to other Pacific and Indian regions, although microsatellite analyses of 4 markers revealed no significant genetic differentiation. Further studies are needed to clarify the precision of natal philopatry and male-mediated gene flow; however, this study provides valuable insights about the phylogeography of green turtles in Japan. Our results also underscore the need for green turtle conservation in the northwest Pacific Ocean. KEY WORDS: Sea Turtle · Pacific Ocean · mtDNA · Phylogeography · Conservation · Microsatellite · Chelonia mydas Full text in pdf format PreviousNextCite this article as: Nishizawa H, Abe O, Okuyama J, Kobayashi M, Arai N (2011) Population genetic structure and implications for natal philopatry of nesting green turtles Chelonia mydas in the Yaeyama Islands, Japan. Endang Species Res 14:141-148. https://doi.org/10.3354/esr00355 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 14, No. 2. Online publication date: July 07, 2011 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2011 Inter-Research.

Size composition and reproductive biology of the ornate jobfish Pristipomoides argyrogrammicus (Lutjanidae) off Ishigaki Island, Okinawa

The ornate jobfish Pristipomoides argyrogrammicus is an important lutjanid species for fisheries in the Okinawan region of Japan. The present study estimated the size composition and reproduction of this species in the waters around Ishigaki Island, Okinawa Prefecture. The length–frequency distribution indicated that males grow larger than females. The fork length (FL; mm)–whole body weight (BW; g) relationship and FL–total length (TL) relationship were as follows: BW = 1.048 × 10−5 FL3.121 and TL = 1.101 × FL + 2.196, respectively. The main spawning season was estimated as between April and August, since higher gonadosomatic index (GSI) values were found for both sexes, and matured oocytes were observed in females during these months. The developmental stage of ovaries correlated with the GSI of females. Fecundity ranged from 9,530 to 98,260 oocytes in fish of 177.0 to 278.0 mm FL, and the FL–fecundity relationship was as follows: fecundity = 9.525 × 10−8 FL4.903.

Early intervention in the management of atopic dermatitis.

This issue of the Asia Pacific Allergy (AP Allergy) features important reviews and articles on atopic dermatitis (AD). AD is the most common chronic inflammatory skin disease in [1]. Although AD is a genetically transmitted disease, its full clinical expression is dependent on environmental exposures [2, 3]. Critical genes that predispose to AD include filaggrin mutations as well as genes that control allergic responses such as TSLP and IL-13, and innate immune responses that react to danger signals on initial contact between the patient and its environment [4]. Since AD often starts in infancy, the diagnosis and treatment of AD should focus on control of this common skin disease early in life. Most guidelines for the treatment of AD are written for physicians and subspecialists in allergy and dermatology. In the current issue of the AP Allergy, Lee et al. [5] have written a proposal on Dermatitis Organizer (ADO) guidelines for children targeting the general community involved in the management of AD including patients, parents, medical policy makers, educators as well as health care providers. It includes a comprehensive review of the epidemiologic characteristics of AD, its natural course, and an approach to the diagnosis and management of AD including the control of environmental triggers such as foods, inhalant allergens and infection as well as the appropriate use of anti-inflammatory therapy which has also been emphasized in other global guidelines and reviews [6, 7]. In this same issue of AP Allergy, Furue and colleagues have updated us with the current status of AD in Japan [8]. Interestingly, the prevalence of childhood AD varies according to geographic location in Japan, e.g. the prevalence of childhood AD is 12-13% in mainland Japan but only about 6% in from Ishigaki Island, Okinawa. Assuming relative genetic homogeneity within Japan, this suggests that the environment plays an important role in clinical expression of AD. However, overcoming patient and family's behavior about AD are difficult hurdles in bringing best care to these individuals, e.g. topical steroid phobia is common in patients thereby leading to undertreatment of patients and persistent skin inflammation in AD. Readers of this journal will also find several other interesting articles on AD. On January 28th-29th, 2011, an international group of AD investigators gathered in Jinan-gun, Korea to participate in the First West Pacific Allergy Forum on a Better Environment for Atopic Dermatitis. During the Jinan Conference, there was a strong emphasis on the environment in contributing to the clinical phenotype of AD. In a hypothesis & experience article, Lee and coauthors [9] summarize their presentation at the Jinan Conference where they reported data supporting the role of indoor air quality in contributing to severity of AD. They found that severity of AD was reduced when patients were hospitalized in a low pollution hospital room suggesting that pollution, which has been on the rise in Korea, contributes to severity of AD. In this issue, Munasir et al. [10] reports on the role of allergic risk and other factors that affect the occurrence of AD in the first 6 months of life in Indonesia. Fifty-seven percent of AD presented in the first month of age and immunologic changes could be detected in many of the patients. These findings suggest the importance of early intervention in AD. In a separate article from Thailand, Kulthanan and coauthors [11] describes the clinical features of extrinsic and intrinsic types of adult-onset AD. Extrinsic AD affected 87.5% of adult-onset AD. However both groups had similar severity of skin disease. Interestingly, elevated serum IgE levels was detected in only 37% of extrinsic AD. Positive skin prick test to food and inhalant allergens were more sensitive in detecting extrinsic AD supporting the importance of studying the role of specific allergens in these patients. In summary, the inclusion of a theme on AD in this early edition of the AP Allergy is an important step in the evolution of this young journal as AD is often the first step in the atopic march. It also recognizes AD as part of a multi-organ disease. Early intervention in the treatment of allergic diseases are important initiatives to promote a decline in the prevalence of AD and allergy in the Asian-Pacific region. I look forward to seeing more papers on the important topic of AD published in future issues of AP Allergy.

Current status of atopic dermatitis in Japan

Atopic dermatitis (AD) is a common, chronic or chronically relapsing, severely pruritic, eczematous skin disease. AD is the second most frequently observed skin disease in dermatology clinics in Japan. Prevalence of childhood AD is 12-13% in mainland Japan; however, it is only half that (about 6%) in children from Ishigaki Island, Okinawa. Topical steroids and tacrolimus are the mainstay of treatment. However, the adverse effects and emotional fear of long-term use of topical steroids have induced a "topical steroid phobia" in patients throughout the world. Undertreatment can exacerbate facial/periocular lesions and lead to the development of atopic cataract and retinal detachment due to repeated scratching/rubbing/patting. Overcoming topical steroid phobia is a key issue for the successful treatment of AD through education, understanding and cooperation of patients and their guardians.

Phenotypic and genetic characterization of rhizobia associated with alfalfa in the Hokkaido and Ishigaki regions of Japan

Twenty five rhizobial isolates were obtained from root nodules of Medicago sativa inoculated with soil samples collected from the Sapporo region and Ishigaki Island in Japan. To study their diversity and characterize them in relation to the climatic conditions of their soils of origin, a polyphasic approach analyzing stress tolerance, symbiotic and genetic properties was used. Stress tolerance assays revealed marked variations in salinity, pH and temperature tolerance. Isolates originating from a sub-tropical climate in alkaline soil (Ishigaki Island) tolerated high temperature, salinity and pH levels. Moreover, isolates recovered from a temperate climate in acidic soil (Sapporo) were sensitive to high temperature and salinity, and tolerated acidic pH. Phylogenetic analysis of conserved 16S rRNA and recA genes, and symbiotic nodA and nifDK revealed 25 isolates to be closely related to Ensifer meliloti. Furthermore, the branch patterns of phylogenetic trees constructed from different genes revealed the existence of at least two E. meliloti types in the soils studied. These results may be relevant to programs directed towards improving crop productivity through biofertilization with locally adapted and genetically defined strains.

Effects of Day-length Treatment and Harvesting Time on the Flowering of Erianthus arundinaceus on Ishigaki Island, Japan

Effects of Day-length Treatment and Harvesting Time on the Flowering of Erianthus arundinaceus on Ishigaki Island, Japan

Characteristics of the ratio of dissolved cadmium to phosphate in subtropical coastal waters of Ishigaki Island, Okinawa, Japan

The ratio of dissolved cadmium (Cd) to phosphate (PO4) in the subtropical coastal area of Ishigaki Island, Okinawa, Japan, was investigated. Twenty vertical seawater samplings were carried out once a month from May 2008 to January 2010. In order to examine how the Cd/PO4 ratio in seawater varies with the oceanographic conditions (i.e., the water temperature–salinity characteristics), the water masses at the study sites were classified into two types: group 1 with a water temperature of >25°C and a salinity range of 34.0–34.4, and group 2 with a water temperature of 34.4. A different phytoplankton assemblage was observed in each water mass defined. Different Cd/PO4 ratios were obtained for the two water mass types, due to the differences between the types in terms of the environmental conditions such as the water temperature–salinity (T–S) characteristics and phytoplankton assemblages, as well as possible variations in the concentrations of dissolved iron, zinc, manganese, and CO2 in seawater in each water mass.

Two new species of Agaricales and a new Japanese record for <i>Chaetocalathus fragilis</i> from Ishigaki Island, a southwestern island of Japan

Two new species of Agaricales and a new Japanese record for Chaetocalathus fragilis from Ishigaki Island, a southwestern island of Japan, are fully described and illustrated: (1) Crinipellis (section Grisentinae) rhizomorphica sp. nov. produces brownish orange, fibrillosesquamulose basidiomata accompanied by white thread-like rhizomorphs on the dead twig, olivaceous hairs in KOH, and oblong-ellipsoid, relatively long basidiospores; (2) Chaetocalathus (section Holocystis) fragilis is a new record for Japan, growing on the dead twig; (3) Psilocybe (section Cubensae) capitulata sp. nov. forms a furfuraceous- squamulose pileus, cyanescent flesh, a persistent, membranous annulus, capitulate pilocystidia, and has a coprophilous habit on cow dung.

Levels and distribution of polybrominated diphenyl ethers and organochlorine compounds in sea turtles from Japan

Three species of sea turtles (green, hawksbill and loggerhead turtles) stranded along the coasts or caught (by-catch) around Ishigaki Island and Kochi, Japan were collected between 1998 and 2006 and analyzed for six organohalogen compounds viz., PBDEs, PCBs, DDTs, CHLs, HCHs and HCB. The present study is the first and foremost to report the occurrence of organohalogen compounds in the sea turtles from Japan. Among the compounds analyzed, concentrations of PCBs, DDTs and CHLs were the highest in all the turtle samples. PBDEs were ubiquitously present in all the turtle species. Comparing with the other two species, concentrations of organohalogens in green turtle were relatively low and decreasing trend in the concentrations were noted with increasing carapace length. Concentrations of OCs in sea turtles from the coasts of Ishigaki Island and Kochi were relatively low as compared to those from other locations in the world.

Six new records of species of Macrolepidoptera from Ishigaki Island

Six new records of species of Macrolepidoptera from Ishigaki Island

Isotopic Characteristics of Hydrogen and Oxygen for Groundwater of Nansei Islands, Japan

Isotopic compositions of groundwaters from 13 islands of the Nansei Islands were determined. Mean δD and δ18O values for each island are, respectively, −31 – −20‰ and −5.8 – −4.5‰, decreasing concomitantly with increasing latitude. The oxygen isotopic latitude effect on the groundwaters of the Nansei Islands is estimated as −0.14‰/degree latitude. The temperature effect for δ18O is estimated as 0.20‰/°C. The altitude effect of sampling locations is −0.1‰/100m for δ18O in Yakushima(elevation 1935m). The monthly δD and δ18O values of collected seepage waters from Omoto Tunnel in Ishigaki Island are almost constant for this observation period. Their isotopic composition indicates that precipitation is well mixed during infiltration into the groundwater. The d-parameters for summer precipitation of all islands are almost identical(about 10). However, in winter, the d-parameters(>25) for the northern islands(Tanegashima, Yakushima, and Nakanoshima) were higher than those(<22) for the southern islands.

Contamination status and spatial distribution of organochlorine compounds in fishes from Nansei Islands, Japan

Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants.

First Record of Avian Plasmodium DNA from Mosquitoes Collected in the Yaeyama Archipelago, Southwestern Border of Japan

We studied the prevalence of avian Plasmodium in 509 mosquitoes of 9 species collected from the Ishigaki and Iriomote islands in the Yaeyama Archipelago, located southwest from the mainland of Japan. Two identical avian Plasmodium lineages were detected from Culex (Culiciomyia) nigropunctatus. Detected lineages were phylogenetically classified into different clade to avian Plasmodium lineages from birds and mosquitoes in the mainland of Japan but identical to a lineage detected from a resident bird, White-breasted Waterken (Amaurornis phoenicurus). This is the first detection of avian Plasmodium DNA from mosquitoes in the Yaeyama Archipelago and suggested that resident birds might have been infected with an avian Plasmodium lineage specific to the studied area and C. nigropunctatus could be the candidate vector mosquito species.

Induction of host-plant preference in Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle, Brontispa longissima, is a serious invasive pest of coconut palm (Cocos nucifera) in Southeast Asia and the Pacific region. Recently, however, it has been reported that on Ishigaki Island, Japan, where C. nucifera is rare, the endemic palm Satakentia liukiuensis serves as a regular host. To explore this phenomenon, we examined the preferences of the beetle for the two palm hosts by choice tests and measurements of feeding amount using four different groups: naïve adults obtained from a colony reared on C. nucifera (NC); naïve adults from a colony reared on S. liukiuensis (NS); wild adults collected on C. nucifera on Ishigaki Island (WC); and wild adults collected on S. liukiuensis on Ishigaki Island (WS). Both NC and NS consumed significantly more C. nucifera leaves than S. liukiuensis leaves and were observed more often on the leaves of C. nucifera. These results suggest that B. longissima has an innate preference for C. nucifera. In contrast, field-collected adults (WC, WS) initially showed preferences for the species on which they were collected, but after exposure to the other host plant for 2 weeks, their preferences for that host increased. These results suggest that the feeding experience of B. longissima adults affected their subsequent host preferences. This flexible host preference may have facilitated the beetle’s successful establishment in novel Japanese habitats where the original host plant was rare.

Genotypic Diversity of Theileria orientalis Detected from Cattle Grazing in Kumamoto and Okinawa Prefectures of Japan

Theileria orientalis is a benign protozoan species that is widely distributed in Japan, yet sometimes causes serious economic losses in the livestock industry. In this study, we conducted a molecular survey based on genes encoding the major piroplasm surface protein (MPSP) and p23 for T. orientalis detected in cattle grazing in southern areas of Japan, consisting of 2 farms in Kumamoto prefecture (Aso and Kuma districts) and 3 farms in Okinawa prefecture (Ishigaki, Iriomote, and Yonaguni Islands). High prevalence rates of T. orientalis infection were shown in all the cattle populations using the diagnostic MPSP- and p23-PCR assays. Phylogenetic analyses revealed 4 MPSP genotypes and 3 p23 genotypes. Furthermore, MPSP genotype-specific PCR methods were developed in this study and wide distributions of 5-district genotypes of T. orientalis were observed for the examined farms. Our results indicate that at least 5 types of T. orientalis exist in Kumamoto and Okinawa prefectures of Japan and that genotype-specific PCR assays are highly applicable for the quarantine of transported cattle and for epidemiological surveys of bovine theileriosis in Japan.

Distribution of boulders at Miyara Bay of Ishigaki Island, Japan: A flow characteristic indicator of tsunami and storm waves

AbstractThis study investigates the distribution of boulders at Miyara Bay of Ishigaki Island, Japan. These boulders were deposited on a reef flat extending approximately 400–1300 m in width. Most boulders were rectangular to ellipsoidal, without sharp broken edges. They are reef and coral rock fragments estimated as &lt;335 m3 (&lt;633 t). Locally in the bay, the relationship between the boulder weight and position shows that boulders of a given weight have a clear limit on seaward distribution on the reef flat. For example, more than 1, 10, and 100 tons of boulders were deposited, respectively, more than 500, 300, and 100 m from the reef edge. The line is consistent with the possible landward transport limit by maximum storm waves at the Ryukyu Islands, suggesting that the line was formed by the reworking of some boulders by maximally strong storm waves, although we can not exclude the possibility that the line was formed by tsunamis. Furthermore, 68% of boulders at the bay are deposited beyond this line. Therefore, the presence of these boulders at their present positions is difficult to explain solely by storm waves, implying the possible tsunami origin of these boulders. The boulders are characteristically concentrated along the high‐tide line, suggesting the drastic reduction of the tsunami hydraulic force along the line. Previous studies using radiocarbon age dating, as well as our study, imply that at least 69 boulders at Miyara Bay were probably deposited at their present positions by the 1771 Meiwa tsunami, although some of these boulders might have been emplaced and displaced on the reef flat by prior tsunami or storm surges.

Dynamic evolution of nutrient discharge under stormflow and baseflow conditions in a coastal agricultural watershed in Ishigaki Island, Okinawa, Japan

AbstractExcessive terrestrial nutrient loadings adversely impact coral reefs by primarily enhancing growth of macroalgae, potentially leading to a phase‐shift phenomenon. Hydrological processes and other spatial and temporal factors affecting nutrient discharge must be examined to be able to formulate effective measures for reducing nutrient export to adjacent reefs. During storm events and baseflow periods, water samples were obtained from the tropical Todoroki River, which drains an intensively agricultural watershed into Shiraho coral reef. In situ nutrient analyzers were deployed for 6 months to hourly measure dissolved nutrient (NO3−‐N and PO43−‐P) concentrations. Total phosphorus (TP) and suspended solid concentration (TSS) were increased by higher rainfall intensity (r = 0·94, p &lt; 0·01) and river discharge Q (r = 0·88, p &lt; 0·01). In contrast, NO3−‐N concentration tends to decrease drastically (e.g. from 3 to 1 mg l−1) during flood events. When base flow starts to dominate afterwards, NO3−‐N manifested an increasing trend, but decreases when baseflow discharge becomes low. This counter‐clockwise hysteresis for NO3−‐N highlights the significant influence of groundwater discharge. N delivery can therefore be considered a persistent process compared to sediment and P discharge, which are highly episodic in nature. Based on GIS analysis, nutrient concentration along the Todoroki River was largely affected by the percentage of sugarcane/bare areas and bedrock type. The spatial distribution of N concentration in the river reflects the considerable influence of subsurface geology—higher N levels in limestone‐dominated areas. P concentrations were directly related to the total length of artificial drainage, which enhances sediment transport. The use of high‐resolution monitoring data coupled with GIS‐based spatial analysis therefore enabled the clarification of control factors and the difference in the spatio‐temporal discharge characteristics between N and P. Thus, although erosion‐reduction schemes would reduce P discharge, other approaches (e.g. minimize fertilizer) are needed to reduce N discharge. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Abrupt shift toward cooler condition in the earliest 20th century detected in a 165 year coral record from Ishigaki Island, southwestern Japan

[1] We analyzed a 165 year δ18O coral record from Ishigaki Island, southwestern Japan, and compared our results with observed sea surface temperatures, as well as with the East Asian winter monsoon and El Niño Southern Oscillation. Coral skeletal δ18O fluctuations were consistent with other available SST information since the 1890s. The coral δ18O data indicated abrupt shift toward cooler condition during 1900–1905, consistent with the extremely cold winter air temperatures observed in Japan in 1902. The cold event was also supported by coral Sr/Ca data. Development of the Siberian High may have intensified the EAWM at this time, in association with active heat convection in the tropics and weak westerlies. This cooling may also have been related to surface ocean freshening in the Ogasawara Islands in the early 20th century. Thus, several phenomena were uniquely coupled during the first few years of the 20th century in the northwestern subtropical Pacific.