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Durations (days: meanSD) of copepodid stages (CI- CVI) of Hemicyclops gomsoensis maintained at 15°C and 25°C. The values for CVI indicate days to death after final molt.
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A 17-month field survey and laboratory experiments were conducted to investigate the life cycle, seasonal population fluctuations, and salinity tolerance in the poecilostomatoid copepod Hemicyclops gomsoensis associated with the burrows of the mud shrimp Upogebia major and the ocypodid crab Macrophthalmus japonicus in the mud-flats of the Tama-Rive...
Contexts in source publication
Context 1
... of the copepod deaths occurred when the copepods crept up the wall of the rearing vessel and got out of the water, which is similar to the observation by Gurney (1944) during his experiment with the Saphirella-like copepodids. There were considerable variations in the durations both among and within stages, and between sexes and temperatures ( Table 1). The total aver- Copepod survival was significantly affected by salinity (one-way ANOVA, F 6, 133 579.9, p0.001). ...Context 2
... present estimates of the stage durations (Table 1) should be viewed with caution because of the high mortalities during the experiments and the large variation among and within stages that may partly be attributable to the experimental conditions applied in this study that were considerably different from those in situ. Under this limitation, if we assume an average duration from the CIs to adult females of 24.0 d at 25°C and a duration from NI to CI of 9 d at 20°C (Itoh, unpublished data), a maximum average generation time from April to November may be roughly estimated at 1 month, which implies the presence of at least 7 generations per year. ...Similar publications
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The biodiversity of mesozooplankton and macrofauna abundance was studied from the grouper culture ponds, Gharo, district Thatta, Pakistan during April 2006 to March 2007. A total of 6 mesozooplankton taxa and 19 macrofauna taxa were recorded from the four fish ponds. The zooplankton community in the fish ponds was representative of marine and fresh...
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Citations
... Adults of some species of the Family Ergasilidae that are parasitic on fish have been reported to occur frequently in plankton communities (Ohtsuka et al. 2004a,b). Hemicyclops are loosely associated with benthic animals, such as polychaetes, ghost shrimps, and crabs (Itoh & Nishida 2007, 2013, and their adults are occasionally found in plankton (Mulyadi 2005, Ohtsuka et al. 2010. In Chinese brackish waters, adults of H. xiamenensis Ohtsuka, Ko & Xu, 2010 occur exclusively in plankton at night, but copepodids do not (Ohtsuka et al. 2010). ...
... In Chinese brackish waters, adults of H. xiamenensis Ohtsuka, Ko & Xu, 2010 occur exclusively in plankton at night, but copepodids do not (Ohtsuka et al. 2010). Among adult females of the species examined (n = 18), approximately 56 % carried egg sacs and/or spermatophores (Ohtsuka et al. 2010), implying that distributional dispersal of the species may be enhanced by its planktonic naupliar and first copepodid stages (Itoh & Nishida 2007 and by the adults. The cyclopoid genus Paramacrochiron is usually associated with jellyfish; however, the adults frequently occur in plankton as well as on the host. ...
Before 2019, adults of the sea louse Caligus undulatus were reported exclusively in
plankton from ocean samples worldwide and were not known to parasitize fish hosts. In 2019, the
first instance of this caligid parasitizing a fish host, Japanese sardinella Sardinella zunasi, was
reported in the Seto Inland Sea, Japan. The presently reported study aimed to investigate the biology
and ecology of adult C. undulatus in plankton communities in the Seto Inland Sea and surrounding
waters from March 2020 to November 2021. The occurrence of sea lice in plankton communities
was restricted to the period of August–January, mainly between October and December
with maximum plankton abundance (10.5 ind. per 1000 m3) recorded on 30 November 2020. All
post-naupliar stages of C. undulatus were found on the host fish, and they represented a typical life
cycle pattern known for Caligus species. The sex ratios in both planktonic and parasitic adults were
not significantly different. The frequency of occurrence of planktonic and parasitic adult females
with egg strings was 68 and 46%, respectively. The number of eggs per string was significantly
higher in parasitic adult females (mean ± SD: 16.9 ± 8.6) than in planktonic females (10.4 ± 10.8).
These data suggest that adult females were detached from their hosts and continued to produce
eggs without feeding. Seasonal migration of S. zunasi to brackish water for spawning may result in
the detachment of mature caligids from the host and may be effective in protecting the offspring,
which are less tolerant of less brackish water.
... The life cycle is likely similar to species belonging to Hemicyclops as this is a common member of the same family (Clausidiidae). Descriptions of some parts of life cycles of Hemicyclops have been published but these have mostly focused on the copepodid stages (Itoh & Nishida, 2007), but it is doubtful if naupliar stages have been described. Based on Hemicyclops species' life cycle, it would be expected that members of genus Clausidium should have six naupliar stages followed by six copepodid stages (the sixth counts as an adult) (Geoff Boxshall, personal communication, June 2018). ...
Evolution and population genetic structure of marine species across the Persian Gulf and Gulf of Oman are shaped by two complex factors: the geological history and the present pattern of marine currents. Characterizing and comparing the genetic structures of co-existing species, such as host–parasite associations, allow the discrimination of the relative importance of environmental factors and life history traits that influenced gene flow and demographic events. In this study, we compare two associated Clausidium copepod species ( C. persiaensis Sepahvand & Kihara 2017 and C. iranensis Sepahvand, Kihara & Boxshall 2019) along the south coast of Iran in two geological settings. We analysed partial nucleotide sequences of the mtCOI gene using divergence estimates (FST) and haplotype networks to infer intraspecific population connectivity in the two Gulfs. The results obtained demonstrate the existence of two genetically and geographically distinct clades, corresponding to the Persian Gulf and Gulf of Oman populations. Our results also indicate high diversity, population expansion and high connectivity among populations of C. persiaensis and C. iranensis in the Persian Gulf and Gulf of Oman.
... Symbionts of upogebiid shrimps can be divided into ectosymbionts and burrow co-habitants (burrow symbionts) (Itani, 2004). In the western Pacific, it is known that ectosymbionts include bopyrid isopods, crabs and bivalves (Kato & Itani, 1995;Itani, 2001Itani, , 2004 and burrow symbionts are shrimps, crabs, copepods, phoronids, bivalves, polychaetes and gobies (Miya, 1997;Anker et al., 2001;Itani, 2001;Sato et al., 2001;Kinoshita, 2002;Itoh & Nishida, 2007;Nara et al., 2008;Kinoshita et al., 2010;Henmi & Itani, 2014a;Inui et al., 2018). ...
Moulting is essential for crustacean growth, but is one of the causes of mortality, because a crustacean cannot move during and just after its ecdysis. In the cases of ectosymbiotic crabs, escape from the host's hostile response may also be a problem during its own ecdysis. In this study, Sestrostoma sp. (Varunidae), an ectosymbiotic crab which clings to the ventral abdomen of upogebiid shrimps with legs that can walk, was studied to clarify how the crab moults and maintains association with the host. Five cases of crab ecdysis were observed, where the crab moulted with its legs clinging to the host abdomen, without detaching from the host body. Time required for moulting was 14–21 min. Shedding of the old exoskeleton (active phase) took only 40–59 s. Sestrostoma sp. detached from the host abdomen and waited in the burrow tube during shrimp ecdysis. The crab then reattached at the same location on the host when shrimp moulting was complete. Our results suggest that Sestrostoma sp. are able to maintain a symbiotic relationship with the same shrimp host after its own ecdysis as well after ecdysis of its host.
... The characteristic life cycle of Goidelia japonica, i.e. planktonic from nauplius to CI and symbiotic from CII to the adult stage, is common to the poecilostomatoid Hemicyclops spp., of which planktonic CI has a characteristic body shape different from the later stages and had therefore previously been identified as a different genus Saphirella (Itoh & Nishida 1995, 2007. Do et al. (1984) described the complete life cycle of Pseudomyicola spinosus (Raffaele & Monticelli, 1885), one of the most common poecilostomatoid copepods associated with bivalve mollusks. ...
The life cycle and precopulatory mate guarding behavior of the poecilostomatoid copepod Goidelia japonica associated with the spoon worm Urechis unicinctus (Echiura) are described based on specimens from 19 worms collected from western Japan. A total of 676 copepods were collected from the host’s rectum (494 copepods) and body surface (182 copepods). Copepod numbers were significantly correlated with host weight. Copepods in the rectum consisted almost completely of copepodids (35%) and adult males (65%), with only one non-ovigerous adult female recorded. In contrast, those on the body surface were all adult males (24%) or females (76%), of which 58% were ovigerous. No nauplii or CI occurred. In the rectum, 36% of the adult males guarded 67% of the copepodids, consisting of CII–CV. From these results, their life cycle is considered as follows: nauplii and CI live as plankton; just before or after molting to CII, they enter the host’s rectum and females are probably soon guarded by males; they grow up to CV there; CV females guarded by males move to the body surface just before the final molt; on the body surface females molt to adults and spawn eggs. Guarding the first symbiotic stage (CII) is a unique precopulatory behavior for symbiotic poecilostomatoid copepods. This can be explained from the viewpoint of evolutionary resolution of the intersexual conflict and advantage for early copepodids in precopula.
... The burrow of a closely related species, M. japonicus, is used by the copepods Hemicyclops gomsoensis Ho &Kim, 1991 andH. spinulosus Itoh &Nishida, 1998, with the former also being found in U. major burrows (Itoh & Nishida, 2007. ...
Sestrostoma toriumii (Takeda, 1974) (Varunidae) is a symbiotic brachyuran crab that uses the burrows of the mud shrimp Upogebia yokoyaiMakarov, 1938 (Upogebiidae) in tidal flats along the coasts of Japan, Korea, and Hong Kong. We studied the host specificity of S. toriumii by quantifying the use of alternative hosts, namely, the callianassid shrimp Nihonotrypaea japonica (Ortmann, 1891) and the brachyuran crab Macrophthalmus banzai Wada & K. Sakai, 1989 (Macrophthalmidae). Sestrostoma toriumii was present at higher densities in tidal flats dominated by U. yokoyai and N. japonica, but was never found in tidal flats dominated by M. banzai. Laboratory experiments showed that S. toriumii used the burrows of N. japonica in almost the same way as described previously for their use of U. yokoyai burrows; however, S. toriumii used the burrows of M. banzai less frequently than those of N. japonica. Sestrostoma toriumii avoided hostile responses of the host species through escape and pass-under behavior to avoid agonistic behavior by the crustacean host when it encountered the crustaceans in artificial burrows built from vinyl tubes. These avoidance behaviors were observed more often in tubes containing U. yokoyai and N. japonica. Our results support earlier field studies that showed most burrow associates of upogebiid shrimps also use callianassid shrimps as hosts. Crabs that utilized M. banzai burrows were nevertheless able to remain in the burrow for a relatively long period. This behavioral plasticity might facilitate host switching by S. toriumii.
... According to the molecular analysis by Cornils and i Siphonostomatoid Neomysidion rahotsu, female, dorsal view (~0.8 mm). (j) Neomysidion rahotsu, dwarf male, ventral (left) and dorsal (right) view (~0.1 mm) (After: (a) (b) Ohtsuka et al. 1996b;(c) Itoh et al. 2001;(d) Ho et al. 2006;(e) Itoh and Nishida 2007; original, through the courtesy of Prof. Jun Nishikawa; (g) Ho et al. 2004; Grygier and Ohtsuka 2008;(i, j) Ohtsuka et al. 2005a; with permission from the Zoological Society of Japan (a, d), Taylor & Francis (b), the Plankton Society of Japan (c, e), Springer-Verlag (g, i, j), and John Wiley (h)) Blanco-Bercial (2013), the genera Paracalanus and Parvocalanus are paraphyletic and Acrocalanus is monophyletic. One of the dominant calanoids in coastal waters, Paracalanus parvus s.l., has been taxonomically confused since the beginning of Japanese planktology (see Table 22.1), and resembles P. parvus, P. indicus, and P. quasimodo (Hiromi, 1987). ...
Recent advances in our understanding of the biodiversity of copepods in Japanese waters are briefly reviewed. It is noteworthy that the two new species of Platycopioida found in Japan are the first record of this order from the Indo-Pacific. Taxonomic revisions of calanoids in Japanese waters have continued based on both morphological and molecular data. Molecular analyses have revealed the presence of cryptic/sibling species in a common species and of intraspecific variations. Complete mitochondrial DNA sequences from copepods have been analyzed for Tigriopus japonicus, which suggest that copepods are genetically ‘eccentric.’ Molecular tools have helped to clarify the phylogenetic relationships of highly modified symbiotic copepods. Population dynamics, life cycles, and distributions of planktonic copepods have been thoroughly investigated in coastal and oceanic waters. These studies highlighted the influence of the Oyashio/Kuroshio currents on the coast, the high mortality of eggs from predation, adaptive responses to phytoplankton blooms, and niche partitioning by habitat and food. Deep-sea calanoids are highly diverse and specialized for detritivory and carnivory. East Asian planktonic copepods have been introduced to America and Europe via ballast water, although Japan not yet received any alien planktonic copepods. In contrast, parasitic copepods have been introduced to Japan via aquaculture. The life cycle of commercially important sea lice was clarified. Because copepods are one of the most abundant metazoans on Earth, more biological but also biomimetic information should be accumulated.
... . (Conway et al., 2003;Itoh and Nishida, 1995, 2007, 2008 ...
The present investigation is based on separation and identification of Planktonic Poecilostomatoida in Bahrakan waters during July, August, October of 2010 and December, February, April of 2011. In this study The order of Poecilostomatida was represented by 3 species, Corycaeus andrewsi and Sapphirina nigromaculata andSaphirella- like copepodid. Abundance of each species was measured in sampling months. The highest density of Poecilostomatoid copepods were recorded in August and October 2010. C. andrewsiwith relative frequency of 73% was dominant species during the studying period among Poecilostomatoida and maximum abundance of it were observed in October 2010. Saphirella- like copepodid was observed in all sampling months. Maximum abundance of this species was in August and October 2010 and this report is the first report of this species in the Persian Gulf. There was Positive significant correlation coefficient between density of C. andrewsi and water salinity (P<0.05) but there was no significant correlation between the rest species and water parameters.
... These burrows could be inhabited by crabs of the genera Sestrostoma (family Varunidae), Pinnixa, Pseudopinnixa and Scleroplax (family Pinnotheridae) and used as a refuge by alpheid shrimp of the genera Lepthalpheus, Stenalpheops, Betaeus, and Athanas [45]. Inside the burrows phoron ids have been found, for example Phoronis pallida [37,82] and copepods [46]. The young of polychaetes of the genus Hesperonoe (family Polynoidae) was found on the carapaces of the burrowing shrimp, while adult polychaetes were found in the sediments inside the burrow [83]. ...
This review is devoted to the different aspects of biology of burrowing shrimp of the infraorders Gebiidea and Axiidea (Crustacea: Decapoda). Information on their taxonomy, morphology and physiology, distribution, burrow architecture, and trophic mode is reviewed. The peculiarities of breeding and development, life history, and the role in the ecosystem of these infaunal species are analyzed. Special attention is given to the species that inhabit Peter the Great Bay of the Sea of Japan.
... In the Tama-River estuary five species of Hemicyclops have been recorded from the burrows of invertebrates, among which H. gomsoensis Ho & Kim is the most abundant, followed by H. spinulosus Itoh & Nishida and H. ctenidis Ho & Kim which are much rarer (Itoh 2001, Itoh & Nishida 2007. These copepods are planktonic during naupliar stages, and shift from the water column to the mudflat substratum during the first copepodid (CI) stage to inhabit invertebrate burrows (Itoh 2001, Itoh & Nishida 2007. ...
... In the Tama-River estuary five species of Hemicyclops have been recorded from the burrows of invertebrates, among which H. gomsoensis Ho & Kim is the most abundant, followed by H. spinulosus Itoh & Nishida and H. ctenidis Ho & Kim which are much rarer (Itoh 2001, Itoh & Nishida 2007. These copepods are planktonic during naupliar stages, and shift from the water column to the mudflat substratum during the first copepodid (CI) stage to inhabit invertebrate burrows (Itoh 2001, Itoh & Nishida 2007. The major benthic habitats of H. gomsoensis are the burrows of the mud shrimp Upogebia major (de Haan) and those of the ocypodid crab Macrophthalmus japonicus (de Haan). ...
... The major benthic habitats of H. gomsoensis are the burrows of the mud shrimp Upogebia major (de Haan) and those of the ocypodid crab Macrophthalmus japonicus (de Haan). Hemicyclops spinulosus have been found from burrows of M. japonicus and those of the polychaete Tylorrhynchus heterochaetus (Quatrefages) (Itoh 2001, Itoh & Nishida 2007, 2008, while H. ctenidis occurs in the burrows of another polychaete Hediste sp. (referred to as Neanthes japonica (Izuka) in Ho & Kim 1990). ...
We examined the potential advantage of the association of Hemicyclops species with decapod burrows in their avoidance from fish predators through gut-content analysis of fishes collected from the estuary of the Tama River, Japan, and an experiment applying model burrows. The small gobiid species Pseudogobius masago, collected from an area dominated by burrows of the ocypodid crab Macrophthalmus japonicus, showed a high frequency of Hemicyclops gomsoensis in their guts relative to the other co-occurring fish species. In the experiment, no significant difference was observed in the numbers of H. gomsoensis eaten by the goby between the treatments with and without the model burrows. Another goby, Acanthogobius flavimanus, from an area dominated by burrows of the mud shrimp Upogebia major, showed very low frequencies of H. gomsoensis in their guts, as compared with those in P. masago. They had also ingested H. spinulosus and H. ctenidis, in spite of the overwhelmingly high abundance of H. gomsoensis in the burrows. The number of H. gomsoensis eaten by A. flavimanus was significantly lower in the treatments with the model burrows than in the absence of burrows. Since A. flavimanus was the most dominant demersal fish in the study area, H. gomsoensis seemed to avoid predation from this potentially strong predator by inhabiting the decapod burrows. H. ctenidis and H. spinulosus seemed to avoid predation by trespassers by inhabiting the smaller burrows of polychaetes, but this strategy may be less efficient against large predators that feed on polychaetes.
... The so-called ''Saphirella-like'' copepodids of Hemicyclops were occasionally collected in both mangrove and adjacent coastal waters, but were more abundant in the latter. The genus Hemicyclops with its first-stage copepodid occurring as plankton is closely associated with various benthic borrowers that are normally found in the estuary, coastal inlet, and mudflat (Boxshall & Halsey, 2004;Itoh, 2006;Itoh & Nishida, 2007). Thus, as in our study, Hemicyclops copepodids were more abundant in nearshore waters close to coastal mudflats. ...
Zooplankton, sampled at five stations from the upper Sangga estuary (7km upstream) in Matang Mangrove Forest Reserve (MMFR),
Malaysia, to 16km offshore, comprised more than 47% copepod. Copepod abundance was highest at nearshore waters (20,311indm−3), but decreased toward both upstream (15,572indm−3) and offshore waters (12,330indm−3). Copepod abundance was also higher during the wetter NE monsoon period as compared to the drier SW monsoon period, but vice
versa for copepod species diversity. Redundancy analysis (RDA) shows that copepod community structure in the upper estuary,
nearshore and offshore waters differed, being influenced by spatial and seasonal variations in environmental conditions. The
copepods could generally be grouped into estuarine species (dominantly Acartia spinicauda Mori, Acartia sp1, Oithona aruensis Früchtl, and Oithona dissimilis Lindberg), stenohaline species (Acartia erythraea Giesbrecht, Acrocalanus gibber Giesbrecht, Paracalanus aculateus Giesbrecht, and Corycaeus andrewsi Farran) and euryhaline species (Parvocalanus crassirostris Dahl, Oithona simplex Farran, and Bestiolina similis (Sewell)). Shifts in copepod community structure due to monsoonal effects on water parameters occurred at the lower estuary.
Copepod peak abundance in mangrove waters could be associated with the peak chlorophyll a concentration prior to it. Evidence of copepod consumption by many species of young fish and shrimp larvae in the MMFR estuary
implies the considerable impact of phytoplankton and microphytobenthos on mangrove trophodynamics.
KeywordsCommunity structure–Abundance–Copepods–Mangrove estuary–Coastal waters
