Moon Periods Research Articles

SEXUAL MATURITY, REPRODUCTIVE CYCLES, AND JUVENILE RECRUITMENT OF PERISESARMA GUTTATUM (BRACHYURA, SESARMIDAE) AT PONTA RASA MANGROVE SWAMP, INHACA ISLAND, MOZAMBIQUE

The sesarmid Perisarma guttatum is the most abundant crab species inhabiting the lower mangrove areas at Inhaca Island, and presumably an ecologically important species in this habitat. Among the scarce available information on its population ecology, this species is known to follow a semilunar rhythm of larval release, with breeding probably extended year-round. In this study, a population of P. guttatum was examined, from which estimates of sexual maturity were carried out for both sexes, and breeding activity was monitored to describe short-term variation of reproductive intensity. In an attempt to relate reproductive cycles with recruitment patterns of young, a systematic random sampling design was used to quantify and describe the juvenile population. Reproductive parameters in adults and density estimates for juveniles were obtained from samples taken at 4-d intervals over a 3-mo period. Reproductive activity increased over the study period. Females released larvae around the new and full moon, but lunar variation of the ovigerous ratio with peaks preceding full moon periods indicated that different breeding groups may account unevenly for the reproductive output of the population. Very young recruits made up the larger fraction of the juvenile population, and their density increased from the beginning to the end of the sampling season. Density variation pattern of first-crab stages followed fortnight cycles, but slow growth prevented recruitment pulses to be tracked in size-frequency distributions. Polymodal distributions corresponded to recent recruits and older juveniles originating from previous settlement seasons. Growth rates of identified age groups suggest that sexual maturity in females is likely to be achieved after 2 years or more.

Do lunar cycles influence in vitro fertilization results?

Our objective was to investigate the lunar influence on IVF-ET outcomes. Between 1992 and 1999 we have completed 7572 preprogrammed IVF-ET treatment cycles with the same stimulation protocol in two outpatient units. (Vienna, Austria and Budapest, Hungary) Multiple regression (SAS; proc Logistic) and two separate analyses were performed on pregnancy rates using a harmonic sinoidal trend based on the synodic and anomalistic lunar cycles respectively. The overall pregnancy rate was 30.9%. The amplitude of harmonic sinoidal, trend for the synodic lunar cycles was chi2 = 1.63,2d.f., p = 0.44 and chi2 = 6.27,2d.f., p = 0.044 for the anomalistic moon periods. For the anomalistic lunar months the amplitude of harmonic sinoidal trend was borderline in terms of higher pregnancy rates with the moon in Perigee. The cause of seasonal changes in IVF-ET outcomes is probably very complex. Our results indicate that lunar influence may only be one of the contributing factors. Further studies are needed to clarify unexplained fluctuations of pregnancy outcomes.

Zooplankton community structure and water flow in the lee of Helix Reef (Great Barrier Reef, Australia)

To investigate which physical processes contribute most in moulding zooplankton community structure in the waters close to coral reefs, light traps moored in a grid pattern were used to collect zooplankton from the sea surface at 16 stations on the downstream side of Helix Reef during three time periods (2100–2200, 2400–0100, and 0300–0400 hours) over three consecutive nights covering the new moon period in January 1992. Two distinct zooplankton communities were present: a community composed primarily of reef-resident, demersal plankton immediately to the south of the reef in an area of reduced flushing, and a community containing coastal and shelf-seas taxa at the more exposed sites in the open flow field. The fauna composition at a number of exposed stations was as rich as that at sheltered stations both in terms of number of taxa and diversity indices but was almost an order of magnitude less abundant. The reef-resident, demersal plankton community was dominated by gammarid amphipods, mysids, and polychaetes, whereas only transient, meroplanktonic forms such as echinoderm and echinopluteus larvae and shelf-seas, holoplanktonic forms such as doliolids and larvaceans were significantly more abundant in the exposed community. Zooplankton associations were apparently formed by a combination of hydrodynamic processes, spatial and temporal distribution patterns of individual taxa, specific behaviours of certain taxa, and the interactions among taxa at different trophic levels.

Daily growth increment formation and its lunar periodicity in otoliths of the myctophid fish Myctophum asperum (Pisces: Myctophidae)

: The surface-migratory myctophid fish, Myctophum asperum, of the western North Pacific was found to have daily growth increments of its sagittal otolith, which also exhibited lunar periodicity in the deposition of increments. Daily deposition of the otolith increments was verified because the width of the marginal increment increased during the night and early morning between 20.00 h and 08.00 h and its growth stopped during the day. An autocorrelation analysis of the increment widths, which were measured consecutively in 11 specimens covering 33 synodic months, also showed a lunar periodicity in increment deposition. The mean increment widths during five days around the time of a full moon were significantly narrower than those around a new moon in 18 of the 33 full moon cases (P < 0.01: Student's t-test) and, on average, tended to be narrow in 29 cases. The cause of this tendency is thought to be slower growth caused by staying in deeper and colder habitat due to the suppression of diel vertical migration and/or lower food availability resulting from the possible dispersion of zooplankton during the full moon period.

Vertical distributions of late stage larval fishes in the nearshore waters of the San Blas Archipelago, Caribbean Panama

Light traps were used to describe the vertical distribution of late larval stages of reef fishes in the San Blas Archipelago during three successive new moon periods. Traps were deployed in the lagoon and at an exposed site on the outer reef edge. At each site, two traps were anchored at the surface and two traps just above the bottom. Most families of reef fishes that were abundant in catches displayed clear patterns of depth preference. The larvae of gerrids, pomacentrids and lutjanids were predominantly captured in shallow traps, while gobiids, labrids, apogonids and blenniids were usually collected in deep traps. Studies that used lights to aggregate and collect larval fishes display marked differences in the composition of catches between the Great Barrier Reef (GBR) and the Caribbean. In order to determine whether such results were due to biases inherent in different sampling methods, or to locality-specific patterns of larval behaviour, we simultaneously deployed light traps and dip-netting around lights during three new moons in the San Blas Archipelago. We found that these sampling techniques collected differing components of the larval fish assemblage from the same water mass. However, there remains good evidence for the existence of locality-specific responses to light in older larval stages, suggesting that broad generalisations about patterns and causes of vertical distributions may be difficult to achieve.

First results from mesospheric airglow observations at 7.5º S.

The Cariri Airglow Observatory has been in operation since November, 1997. This observatory has a multi-filter photometer to measure the airglow emission intensities in the frequencies of OI557.7 nm, OI630.0 nm, NaD, OH(6,2) band, O2 Atmospheric (0-1) band , and the OH and O2 rotational temperatures. The observatory is located at Sao Joao do Cariri, State of Paraiba, one of the driest region in Northeast Brazil, situated at 7.4oS, 36.5oW. Day to day continuous observations (13 days around the new moon period) allow us to study nocturnal, day to day and seasonal variation of the airglow emission intensities. The nocturnal variations of the mesospheric emissions and OH(6,2) rotational temperature have shown strong seasonal dependence with maxima in equinox and minima in solstice. The OI557.7 nm presented the largest relative amplitude (0.42) whereas the rotational temperature presented the smallest relative amplitude (~0.03) and annual averages equal to 231 K. The annual averages of the intensities in OI557.7 nm, O2(0,1) and OH(6,2) were 124 R, 321 R and 1323 R, respectively. Variation of airglow intensities of 2 and 3 days were observed in OI5577 and O2(0,1).

Monitoring the moon's transient atmosphere with an all-sky imager

Abstract An indispensable tool in terrestrial aeronomy, all-sky imaging has recently been shown to be useful in studies of the Moon's exosphere. Two days after the peak of the 1998 Leonid meteor shower, an extended region of neutral sodium emission was detected in the night sky using a bare-CCD imaging system. The feature was found to be a train of sodium gas originating from the Moon. Subsequent observations indicate the feature is normally visible (max. brightness ∼15–90 Rayleighs (R)) during nights near the time of new Moon. Monthly monitoring of the feature using an all-sky system can provide useful information about the time-variability of the lunar atmosphere. Several processes are believed to be responsible for the production of lunar Na and evidence is presented indicating that two of these processes were each responsible for the observed brightness enhancements of the sodium feature on two separate new Moon periods in January and March 2000.

Whale sharks Rhincodon typus aggregate to feed on fish spawn in Belize

This study confirms reports by fishermen of a large and predictable aggregation of whale sharks Rhincodon typus along the Belize Barrier Reef. Although whale sharks are rarely sighted at this location during most of the year, we counted as many as 25 whale sharks in a 50 m diameter area on 1 occasion and tagged 6 sharks during a 22 min period on another. The whale shark aggregation coincides seasonally and temporally with a multispecies reef-fish spawning aggregation at a reef promontory, Gladden Spit, at sunset, during the full and last-quarter moon periods of April and May each year. We report here, for the first time, that whale sharks feed on the freshly released spawn of cubera snappers Lutjanus cyanopterus and dog snappers L. jocu (Lutjanidae), and have documented the phenomenon with still and digital video photography of hundreds of feeding events. There is consensus locally that this remarkable interaction is in need of immediate protection from overfishing of snappers and unregulated tourism development. Our continued investigations are providing management recommendations for a new marine reserve at the site.

Traveling ionospheric disturbances observed in the OI 630‐nm nightglow images over Japan by using a Multipoint Imager Network during the FRONT Campaign

Pilot observations using a network of five all‐sky imagers (ASIs) were conducted during the new moon period of May 19–22, 1998 as part of the F‐region Radio and Optical measurement of Nighttime TID (FRONT) campaign. The network observation enabled us to track propagation of medium‐scale traveling ionospheric disturbances (TIDs) in the OI 630‐nm nightglow over a distance of more than 2500 km. The TIDs were observed every night during the campaign period, but occurrence was limited from evening to midnight. They have horizontal wavelengths of 200–600 km, travel a horizontal distance of more than 1000 km, and last for more than three hours. In every case, the TIDs moved southwestward with a velocity of 83–137 m/s. Using dual‐site TID images, the altitude of the TID structures in the 630‐nm nightglow was calculated to be ∼260 km, which corresponds to the bottom side of the mid‐latitude ionospheric F layer.

Discovery of the distant lunar sodium tail and its enhancement following the Leonid Meteor Shower of 1998

Night‐time measurements using a bare CCD all‐sky imaging system have detected the presence of an extensive region of neutral sodium emission (589.1 nm) in the direction of the anti‐solar/lunar points. The emission was observed to occur during the nights of 21–22 August and 18–20 November, 1998 UT, centered on the new Moon period. The Moon is the most likely source of the neutral sodium, making this the first detection of the lunar sodium tail out to a distance of hundreds of lunar radii. The greater brightness of the emission feature on 19 November is attributed to the Leonid meteor shower which peaked on 17 November, 1998, less than two days before new Moon.

Distribution of final stage phyllosoma larvae and free-swimming pueruli of Panulirus japonicus around the Kuroshio Current off southern Kyusyu, Japan

The distribution of the phyllosoma larvae and free-swimming pueruli of the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) has been studied off the south coast of Kyusyu Island. From 1992 to 1995, four research cruises were conducted on board the R.V. “Yoko-maru”. Cruises were mainly carried out over the new moon period between June and August along transect lines that cross the Kuroshio Current. In total, 89 later stage Form F phyllosoma (body lengths ≥20 mm) and 43 free-swimming pueruli of P. japonicus were caught; 94.4% of the later stage phyllosoma larvae were in the final stage. The phyllosoma were distributed widely in and south of the Kuroshio Current, where high-salinity (34.8) water exists at depths below about 80 m. Highest densities of the final phyllosoma larvae were observed in or near the Kuroshio Current, and molting to the puerulus stage also occurred in the same area. Free-swimming pueruli were mainly sampled in and north of the Current. It is suggested that the pueruli of P. japonicus swim across the Kuroshio Current to settle in coastal areas.

Height measurements of nightglow structures observed by all-sky imagers

To determine altitudes of nightglow wave structures, we have carried out simultaneous observations of OH Meinel bands and OI 557.7-nm emissions using four all-sky CCD imagers at two separated site. Two imagers were set up at the Shigaraki MU Observatory (34.85°N, 136.11°E), and two others were set up at the Muroh Observatory (34.57°N, 136.01°E). The range between the two sites is about 32 km. Observations were conducted during the new moon period from 21 January to 3 February 1998 as a part of the Planetary Scale Mesopause Observing System (PSMOS) campaign in Japan. On the night of 24–25 January, 1998, two orthogonal wave structures were observed at both sites. To determine the altitudes of nightglow structures, we use a new technique which is an application of a triangulation method. From the obtained images, we succeeded to derived a distribution of the altitudes differing by as much as 10 km across the field of view apparently in association with a large scale intensity variation.

Evening fish choruses near coral reef systems in the Great Barrier Reef, Australia

The nighttime ambient sea noise on and around coral reef systems in northern Australia is characterized by choruses produced by nocturnally active fishes. These choruses are produced year round, from dusk to dawn. Choruses are composed of many ‘‘pops’’ of between 5 and 28 ms length, with a decay envelope suggestive of a lightly damped swimbladder and with source levels calculated at 154–157 dB re: l μPa2 at 1 m peak to peak. Sources are found mostly concentrated over 6–20 m water depth. Choruses have a mean spectral peak at 550 Hz (normal range 500–750 Hz) but may influence sea noise from 100 Hz to 3 kHz. The highest chorus levels occur just after dusk or in the early evening, reaching up to 35 dB above background levels. The recorded levels of choruses displayed distinct daily patterns, lunar patterns with higher levels around new moon periods, and seasonal patterns of highest level during the austral summer. Choruses occur over large spatial scales, with active sources heard at up to 15 km from reef systems and chorus influence on ambient sea noise extending considerably further. It is believed that nocturnal planktivorous fishes, such as those from the families Holocentridae and Priacanthidae, are responsible for choruses. [Work supported by the Australian Defence Science and Technology Organization.]

Mass Settlement and Post-Settlement Mortality of Epinephelus Merra (Pisces: Serranidae) On Réunion Coral Reefs

An unusual mass settlement event of the grouper Epinephelus merra occurred on the fringing coral reefs of Reunion Island (south-western Indian Ocean) in April 1994. This major event coincided with stormy conditions associated with the new moon period. The abundance of new settlers was surveyed for 45 days following settlement on both the reef flat and the back reef area of the coral reefs of St Gilles, La Saline and St Leu. Mean densities of settlers were higher on reef flats (maximum 474 ind/20 m2 at La Saline) than on back reef areas (maximum 156 ind/20 m2 at La Saline). Seven weeks later, densities of settled E. merra had drastically decreased, and did not differ with site and zone (18.5 ind/20 m2). Percentages of post-settlement mortality at that period ranged from 85 to 88% in back reef areas and from 93 to 95% on reef flats. A strong correlation between density of recruits and per capita mortality suggests density-dependent early post-settlement mortality for E. merra. The limitation of food resources and shelters, perhaps combined with an increase of diseases due to high population densities of settlers, was probably the main cause of mortality just after the mass settlement. Predation by reef fish, including cannibalism between settlers, is probably responsible for most subsequent mortality.

Spawning aggregations:patterns of movement of the coral trout Plectropomus leopardus (Serranidae) as determined by ultrasonic telemetry

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 162:253-263 (1998) - doi:10.3354/meps162253 Spawning aggregations: patterns of movement of the coral trout Plectropomus leopardus (Serranidae) as determined by ultrasonic telemetry Dirk C. Zeller* Department of Marine Biology, James Cook University of North Queensland, Townsville, Queensland, 4811, Australia *E-mail: dirk.zeller@jcu.edu.au This study measured biological variables necessary for determining the dynamics of spawning aggregations and measured the influences of these variables on effects of fishing on these aggregations. Four major spawning aggregation sites of Plectropomus leopardus (Serranidae) were identified at Lizard Island, Northern Great Barrier Reef, Australia, using ultrasonic telemetry. Spawning aggregation activities displayed a lunar pattern, with peak activities during new moon periods in the austral spring-early summer. Of 35 fish tracked during spawning periods in 1993-95, only 31% participated in spawning aggregations, despite all specimens being sexually mature. All specimens that aggregated displayed fidelity to their chosen aggregation site. The distance between established home ranges and spawning aggregation sites ranged from 220 to 5210 m, with total spawning movements back and forth for individual fish ranging from 600 m to over 17 km. One-way inter-reefal movements were recorded for 3 fish moving 3, 7.5, and 11 km between release and recapture locations. Male fish spent an average of 8 times longer at aggregations than females. Females (n = 4) undertook single-day or overnight trips only, while males (n = 8) often did multi-day trips. Males were also more likely to make several trips to spawning aggregation sites than females. Since males spent more time at aggregation sites, and made more trips to those sites, they were potentially more vulnerable to fishing pressure on aggregations. The reliance on several aggregation sites per reef makes P. leopardus potentially less vulnerable to overexploitation of spawning aggregations. However, the strong site fidelity observed makes individual aggregations vulnerable to depletion. The low participation rate of reproductively mature individuals at major aggregation events (31%) suggested that not all spawning activity took place at the known aggregation sites. Spawning aggregations · Movements · Plectropomus leopardus · Ultrasonic telemetry · Catchment distance · Serranidae · Residence · Sex patterns · Fisheries management · Stock assessment Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 162. Publication date: February 12, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

Spawning behavior and haremic mating system in the corallivorous butterflyfish,Chaetodon trifascialis, at Kuroshima Island, Okinawa

Territorial and spawning behavior ofChaetodon trifascialis were investigated on a small patch of reef at Kuroshima Island, Okinawa, Japan. Three males and 8 females inhabited the reef, each individual defending a territory against conspecifics of the same sex. Each male territory included 2 or 3 female territories. In the daytime, each male frequently visited the females living in its territory. At dusk in the full or new moon periods, courtship began within the female territories, pair spawning subsequently occurring within or near those territories. When a male actively courted a female in the territory of a second male, the latter male immediately chased off the intruder. Thus, mating occurred only between a male and females living in former's territory. This is the first report of a haremic mating system among butterflyfishes (Chaetodontidae).

Influence of environmental factors on the numbers and activity of wintering Lapwings and Golden Plovers

Variations in the numbers and activity of Lapwings Vanellus vanellus and Golden Plovers Pluvialis apricaria using 322 ha of lowland farmland were examined in relation to temperature, rainfall, wind speed and moonphase. The study was undertaken over two winters (1987/88 and 1988/89), with maximum counts of 4000 Lapwings and 820 Golden Plovers. Patterns of occupancy of the study area and seasonal occurrence are described. Temperature and the phase of the lunar cycle seemed to be particularly important in affecting the distribution and activity of the birds. More Lapwings occurred in the study area on the colder and on the wetter days in several months, and also around the full moon period when feeding activity was particularly prevalent. A higher proportion of Lapwings tended to feed on colder days and around the new moon period, while daytime loafing increased around the full moon period. These results support the ideas that birds need to feed more in cold conditions, when energy demands are high, and that night feeding frequently occurs during the full moon period, although the reasons for this remain unclear.

ムラサキウニの生殖年周期と産卵月齢周期性

The annual reproductive cycle and lunar spawning rhythms in the spawning season of the purple sea urchin A. crassispina, which lives in Mera Bay of South Izu in Shizuoka, were examined by the successive change of the gonad index and histological observation of the gonad. The following is the annual reproductive cycle of the purple sea urchin; the gonad become to develop from January to May, the spawning season to be from June to August, and the gonadal growing action to degenerate from September to December. Moreover, it was suggested that this cycle is closely related to the annual change of the sea water temperature. As the population of this species spawned several times every full moon period in the spawning season, they were thought to have lunar spawning rhythm that spawns once each the lunar period. It was suggested that the gonad in the spawning season could recover for the next spawning in about a week.

Modeling the Moon's extended sodium cloud as a tool for investigating sources of transient atmospheres

A review is presented of wide-angle, low-light-level imaging observations of the Moon's extended sodium atmosphere and Monte Carlo simulation studies used in their interpretation. The observational results at quarter and full Moon show dramatically different morphology patterns. The computer model results show that both morphologies are consistent with a single source function and subsequent dynamical evolution of the ejected sodium atoms. Different viewing geometries essentially account for the observational differences. We thus find no need to modify source rates significantly during full Moon periods when the terrestrial magnetosphere shields the lunar regolith from possible solar wind sputtering sources.

Dynamics of fish communities on Reunion fringing reefs, Indian Ocean. II. Patterns of temporal fluctuations

Temporal fluctuations in fish communities on fringing reefs on Reunion Island (south-western Indian Ocean) were studied on three different scales: (1) within months, (2) within year and (3) between years. Greatest species richness and abundance of individuals were found during the full moon periods. This variation may be related to reproductive and/or trophic migrations of fishes inside or outside the reef, or to similar variations of prey populations. Seasonal fluctuations of fish abundance and species richness occurred in the three geomorphological zones and on the four reefs studied, but patterns differed among zones and reefs. Despite the increase in food availability during the austral summer, recruitment processes probably accounted for most of the seasonal fluctuations of fish communities, although it was not clearly evidenced. A decrease in fish abundance was observed in all zones during the 2 yr studied, although the magnitude of this decline differed between reefs. Coral degradation caused by hurricane Firinga impact and/or eutrophication of coral reef waters, may provide partial explanation for these patterns. Nevertheless, large interannual variation in recruitment of young individuals (especially for schooling species) may be the most valuable hypothesis causing the decrease in fish abundance on Reunion Island reefs.