著者
Avril H. Underwood Ilka Straehler-Pohl Teresa J. Carrette Jessica Sleeman Jamie E. Seymour
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.4, pp.143-153, 2018-11-21 (Released:2018-11-14)
参考文献数
71

This research presents the early life history stages of Malo maxima, a recently described tropical Australian cubozoan from the family Carukiidae, from sexual fertilisation to metamorphosis including planula, polyp, asexual reproductive strategies and young medusa. We discuss the similarities between M. maxima and two closely related carukiid species from Japan and Australia including morphology and behaviours previously undocumented in the class Cubozoa. All three carukiids can reproduce by mono-disk strobilation, a strategy common to all other orders of the class Scyphozoa but only recently described in Cubozoa.
著者
Chong Chen Leigh Marsh Jonathan T. Copley
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.1, pp.25-27, 2018-02-28 (Released:2018-03-14)
参考文献数
16

“Mating stacks” have been widely documented in calyptraeid slipper limpets, which are protandric and exhibit sequential hermaphroditism. Gigantopelta is a genus of peltospirid snails endemic to deep-sea hydrothermal vents containing two species, one distributed on the East Scotia Ridge in the Southern Ocean and another on the Southwest Indian Ridge in the Indian Ocean. Here, we report the observation that both species form extensive (often >15 individuals) “snail chains”. These chains are potentially analogous to ‘mating stacks’ of calyptraeids, or alternatively, maybe a behaviour to facilitate spermatophore transfer. Both Gigantopelta species apparently have separate sexes and are sexually mature at a small size. However, it remains unclear whether they undergo sex change during their life.
著者
Yusuke Kondo Shoma Okada Susumu Ohtsuka Takeshi Hirabayashi Aya Adachi Makoto Urata Sho Toshino Hiroshi Miyake Nanako O. Ogawa Naohiko Ohkouchi
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.2, pp.66-74, 2018-05-30 (Released:2018-05-24)
参考文献数
50
被引用文献数
1

In this study, we investigated the trophic interactions between the Japanese giant box jellyfish, Morbakka virulenta, and fish in the central part of the Seto Inland Sea, western Japan, in autumn and winter. Occurring in the surface waters at nighttime, these cubomedusae, regardless of their size (1.5 to 22.5 cm in bell height), were found to be piscivorous, feeding mainly on the Japanese anchovy, as shown by their stomach contents analysis. This finding was supported by a stable isotopic analysis and by an unchanged cnidome, irrespective of the bell height of medusae. Their nocturnal occurrence near the surface often took place around the slack tide, during which the medusae were foraging with tentacles fully extended. Other associations between the medusae and fish were also observed at this time: presumed commensalism with juvenile Japanese horse mackerel, and predation by black scraper.
著者
Mitsuko Hidaka-Umetsu Dhugal J. Lindsay
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.2, pp.41-45, 2018-05-30 (Released:2018-05-24)
参考文献数
14

An individual narcomedusa assignable to Solmissus incisa sensu lato was observed having ingested a fish at 573 m depth near the southeast slope of the Kaikata seamount, Japan. Solmissus is a very common deep-sea narcomedusan genus that is widely considered to be a predator specializing on gelatinous plankton. Several cryptic species, with differences in the number of tentacles and form of manubrial pouches, are thought to be included in the nominal species Solmissus incisa. Therefore, the present study gives a short description of the morphotype of Solmissus incisa s.l. observed with a fish in its stomach, as well as several individuals of the same morphotype that had ingested gelatinous prey.
著者
Susumu Ohtsuka Kazuhiko Koike Dhugal Lindsay Jun Nishikawa Hiroshi Miyake Masato Kawahara Nova Mujiono Juro Hiromi Hironori Komatsu
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.4, no.1, pp.1-13, 2009-02-25 (Released:2009-04-20)
参考文献数
91
被引用文献数
19 30

Since marine medusae and ctenophores harbor a wide variety of symbionts, from protists to fish, they constitute a unique community in pelagic ecosystems. Their symbiotic relationships broadly range from simple, facultative phoresy through parasitisim to complex mutualism, although it is sometimes difficult to define these associations strictly. Phoresy and/or commensalism are found in symbionts such as pycnogonids, decapod larvae and fish juveniles. Parasitism and/or parasitoidism are common in the following symbionts: dinoflagellates, ciliates, anthozoan larvae, pedunculate barnacles, anuropid isopods, and hyperiid amphipods. Mutualism is established between ctenophores and gymnamoebae, and between rhizostome medusae and endosymbiotic dinoflagellates. More information on symbiotic apostome ciliates, anthozoan larvae and hyperiid amphipods is definitely needed for further studies in consideration of their high prevalence and serious damage they can inflict on their hosts. The present paper briefly reviews previously published data on symbionts on these gelatinous predators and introduces new information in the form of our unpublished data.
著者
Kringpaka Wangkulangkul Ruaengrit Promdam
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.4, pp.154-162, 2018-11-21 (Released:2018-11-14)
参考文献数
47

Scale-dependent spatial patterns of coastal benthic assemblages have been analyzed in many studies, especially in temperate regions, but such analyses are scarce in tropical waters. Hierarchical analysis of variance was performed using data from a nested sampling design to test whether variability in assemblages of midshore macrofauna from rocky intertidal ecosystems on the southern Thailand coastline differs over different spatial scales and whether assemblages on natural and artificial rocky reefs are similar. Analyses revealed that the composition of macrofaunal groups on the coastline facing the Andaman Sea did not differ from that of the assemblage on the Gulf of Thailand coastline; however, significant variation was detected on the scale of region (within coast) and shore (within region). The abundance of some macrofaunal groups differed among coasts and regions, but all groups exhibited high variation between shores. High variation between shores may mask larger-scale patterns in the composition of macrofaunal groups. Interestingly, the composition of macrofaunal groups and abundance of each group were not influenced by the type of habitat, suggesting that artificial structures may provide a habitat for hard-bottom species where the natural hard substrate is lacking.
著者
Ron M. L. Ates
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.12, no.1, pp.71-77, 2017-02-28 (Released:2017-02-28)
参考文献数
86
被引用文献数
1 3

Instances of predation and scavenging of jellyfish (pelagic Scyphozoa, Hydrozoa and Ctenophora) by benthic invertebrates are reviewed and presented. Sea anemones and decapod crabs are widespread as well as common predators or scavengers of jellyfish. Dead or dying jellyfish are also preyed upon by species of Echinodermata.
著者
Sakiko Orui Sakaguchi Hiroshi Ueda
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.4, pp.173-179, 2018-11-21 (Released:2018-11-14)
参考文献数
22

Pseudodiaptomus inopinus, a common estuarine calanoid copepod in the Northwest Pacific, has been suggested to be a species complex. The population of the mainland of Japan consists of two allopatric forms that are distinguishable by the length of the posterior processes of the genital operculum; the forms with short and long processes are tentatively called SP- and LP-forms, respectively. We analyzed the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear ribosomal internal transcribed spacer 1 (ITS1) gene of 34 individuals (12 SP- and 22 LP-forms) collected from various localities. The genetic differences between the two forms were 12–15% for COI and 7–10% for ITS1. They were clearly separated into different clades in both COI and ITS1 trees. These results confirmed that the two forms belong to different species. The SP-form is a distinct species because the shape of the genital operculum of P. inopinus s. str. has long posterior processes as in the LP-form. Pseudodiaptomus japonicus Kikuchi, 1928, which is the SP-form and was once synonymized with P. inopinus, is revived. The genetic comparison using available sequence data indicates that Pseudodiaptomus koreanus Soh et al., 2012 is the same species as P. japonicus.
著者
Hiroki Kise Naoko Dewa James Davis Reimer
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.3, pp.136-141, 2018-08-27 (Released:2018-08-29)
参考文献数
32

The species Epizoanthus planus is the only known described zoantharian with an association with echinoderms, and it is known to live on the spines of living sea urchins from the family Cidaridae. This species has been reported from 741 to 1019 m in the Indian Ocean and the East China Sea. However, diagnostic characters are lacking in both the original description and subsequent studies. The present study reports the first record of E. planus from Japanese waters (300–400 m) based on a newly collected specimen, and this record slightly extends the species distribution range in the northwest Pacific Ocean. This new record increases the number of Epizoanthus species in Japanese waters to at least five species. Although many taxonomy and diversity studies have focused on specimens from SCUBA-based collections in Japanese waters, few studies have focused on zoantharians in deeper waters below SCUBA diving limits. The results of the present study highlight the importance of examining specimens from deeper waters to better understand the overall diversity of the order Zoantharia.
著者
Tomohiro Nishimura Wittaya Tawong Hiroshi Sakanari Takuji Ikegami Keita Uehara Daiki Inokuchi Masatoshi Nakamura Takuya Yoshioka Shota Abe Haruo Yamaguchi Masao Adachi
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.2, pp.46-58, 2018-05-30 (Released:2018-05-24)
参考文献数
68

Ciguatera fish poisoning (CFP) is caused by toxins originating from an epiphytic/benthic dinoflagellate of the genus Gambierdiscus. In Japan, CFP cases have been increasingly reported not only in subtropical areas but also in temperate areas. It is therefore important to study Gambierdiscus cell occurrences, cell densities, and population dynamics to address CFP outbreaks in Japan. This study assessed the densities in Japanese shallow waters (0.1–3 m depths) and revealed that the densities were lower than those in tropical and subtropical areas worldwide. In the shallow waters of Tosa Bay, a Japanese temperate area, population dynamics of Gambierdiscus cells were assessed monthly between 2007 and 2013. Gambierdiscus did not show substrate preferences for macroalgal species. The cell densities in the area ranged from 0 to 232.2 cells g−1 wet weight algae. The average cell densities in spring, summer, autumn, and winter were 0.1±0.4, 0.9±2.6, 4.0±20.6, and 0.4±1.4 cells g−1 wet weight algae, respectively. The cell densities in summer and autumn were not significantly different (p>0.05), whereas those in summer and autumn were significantly higher than those in spring and winter (p<0.01). A significant positive correlation between cell densities and sea surface temperatures (SSTs) was observed (rs=0.21, p<0.001), while a significant negative correlation between cell densities and salinity was recognized (rs=−0.18, p<0.001). These results suggest that cell densities of Gambierdiscus in Japanese temperate shallow waters increase in summer and autumn when the SST is high and salinity is moderately low.
著者
Hiroshi Ueda
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.1, pp.28-31, 2018-02-28 (Released:2018-03-14)
参考文献数
14

High-concentration pure glycerol has been used as a medium for permanent preservation of micro-crustacean specimens. However, glycerol-mounted permanent slide preparations are rare because of the difficulty in sealing the coverslip over the long term. I devised a glycerol-mounted permanent preparation method, especially for a small dissected piece of a micro-crustacean using a glass depression slide and a coverslip with secure sealing, in order to overcome some of the disadvantages of the popular permanent mountants that solidify, such as discoloration of specimens and difficulty in remounting. Unique characteristics of the preparation method are: (1) the central glycerol being of a few millimeters in diameter, which embeds the specimen and is retained in the depression center by a paraffin wax circle painted on the depression bottom; (2) the marginal glycerol, which fills up the clearance between the glass slide and the coverslip and prevents intrusion of the sealant into the clearance; (3) sealing with nail polish first and Canada balsam second, where the latter can seal securely over the long term and the former, being a fast-drying sealant, prevents intrusion of the latter into the marginal glycerol. By following this method, even a small dissected piece can be easily found under a microscope and taken out from the preparation for detailed examination with a low risk of going missing. The procedure to make the preparation is presented in detail.
著者
Takeo Kurihara Reiko Fuseya Masaya Katoh Ken Inoue
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.5, no.1, pp.11-16, 2010-02-25 (Released:2010-06-25)
参考文献数
19
被引用文献数
5 4

Giant clams are simultaneous hermaphrodites and are assumed to ejaculate first and, after completely stopping ejaculation, release eggs. In the seed production method aimed at preventing self-fertilization, each adult clam is induced to ejaculate in a tank and then release eggs in another tank. Giant clams, however, have recently been suggested to continue ejaculation for a period after the beginning of egg release. The overlap between ejaculation and egg release might lead to self-fertilization in the tank used for egg release, especially for the eggs released just at the beginning of spawning. We examined the possibility of such self-fertilization for the giant clam Tridacna crocea and obtained three results. (1) In observations with the naked eye in a laboratory, 2 of 38 T. crocea simultaneously ejaculated and released eggs. (2) In a laboratory experiment, 1.5 to 80.0% of eggs released from each adult clam developed into D-shaped larvae without artificial cross-fertilization. Such development occurred more frequently for the eggs released earlier from each adult clam than for the eggs released later from the clam. (3) In observations at a hatchery, 2 to 94% of the eggs released from 4 of 5 adults were found to develop into D-shaped larvae without artificial cross-fertilization. The three results suggest that at least some T. crocea adults continue ejaculation for a period after starting spawning eggs, which causes self-fertilization.
著者
Junya Hirai Yoko Hamamoto Daiske Honda Kiyotaka Hidaka
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.2, pp.75-82, 2018-05-30 (Released:2018-05-24)
参考文献数
38

Metagenetic diet analyses of the 18S V9 region were conducted in 40 adult female Calanus sinicus during winter in Tosa Bay (Japan). The majority of prey items were small crustaceans (of Copepoda and Cirripedia) and diatoms, taxa that are dominant in the environment and have been previously reported as important prey items of Calanus. The abundance of sequences attributable to Dinophyta and Chlorophyta was significantly lower in C. sinicus gut contents than in environmental plankton communities, suggesting that C. sinicus avoids prey from these groups. Hydrozoans were also observed, and aplanochytrids (Labyrinthulea) were detected for the first time as a major prey of C. sinicus. Additionally, high proportions of unclassified eukaryote material were observed, suggesting undetected predator–prey relationships in key copepod species in marine ecosystems. The dietary importance of aplanochytrids, heterotrophic protists that accumulate unsaturated fatty acids such as docosahexaenoic acid, has been overlooked in previous research. Calanus sinicus is a key copepod species in the subtropical coastal regions of the western North Pacific, and a major food source for the larvae of commercially important fish; therefore, further investigation into novel prey items such as aplanochytrids is recommended to understand the complex food web structures in marine ecosystems.
著者
Mikako Gushi Akira Iguchi Ichiro Takeuchi
出版者
The Plankton Society of Japan, The Japanese Association of Benthology
雑誌
Plankton and Benthos Research (ISSN:18808247)
巻号頁・発行日
vol.13, no.1, pp.17-20, 2018-02-28 (Released:2018-03-14)
参考文献数
18
被引用文献数
1

An advanced underwater camera was used for recording coral spawning at a flow-through seawater aquarium. A colony of Acropora digitifera from the reef flat of Sesoko Island, Okinawa, Japan was transferred to a flow-through aquarium and photographed continuously for 5 days at 10 min intervals using an underwater digital camera equipped with a lens wiper. LED lighting was provided. The number of gamete bundle-like particles between the coral and seawater surface was counted on the photographs obtained. The gamete bundle release started around 22:00 pm on 31 May, 2015 (2 h and 50 min after sunset and 3 days before full moon). Spawning was estimated to continue for < 2 hours. The present study indicates that an underwater camera with a lens wiper system will help elucidate the details of coral spawning.