The complete mitochondrial genome of the Japanese mud shrimp Upogebia major (Crustacea, Decapoda)

We determined a full-length sequence of mitochondrial (mt) genome from Upogebia major. This is the first complete mt genome report for infraorder Thalassinidea in Decapoda, Crustacea. Our result showed that U. major generally followed a typical pancrustacean gene order but some tRNA genes showed a very unique gene arrangement such as duplication or translocation. Since none of the complete mt genome sequences in the infraorder Thalassinidea are available yet, this report will provide additional information in relation to mt genome diversity and evolution of the decapods.     

Some peculiarities of the population biology of the ghost shrimp Nihonotrypaea petalura (Stimpson, 1860) (Decapoda: Callianassidae) in coastal waters of Vostok bay, the Sea of Japan

In June 2012, some features of the population biology of the ghost shrimp Nihonotrypaea petalura were studied first for the Russian waters in sublittoral populations of the Vostok Bay (Peter the Great Bay, Sea of Japan). It was found that N. petalura formed aggregations of an average density of 9–19 ind./m² at the depth of 0.2–3 m on rocky and mixed bottoms. The biomass of the aggregations was 15–27 g/m² or 1–33% of the average total biomass of macrozoobenthos, which included animals of 48 taxa. The maximum depth of the shrimp burrows was 52 cm. The populations consisted of animals with body lengths of 17–63 mm. In the size-frequency distribution, two peaks in the number, attributed to the shrimps of 24–29 and 39–48 mm size groups, were observed. The ratio of males to females almost did not vary with size and remained in general close to 1: 0.9 for the surveyed shrimp populations. The local differences in the studied parameters of N. petalura from the Vostok Bay, as well as from other areas of the range, are discussed in relation to features of the habitation of these animals that living in different biotopes.     

The population dynamics and growth of the mud shrimp <Emphasis Type="Italic">Upogebia major</Emphasis> (De Haan, 1841) (Crustacea: Decapoda) from Peter the Great Bay,Sea of Japan

The dynamics of the size–age composition and growth of the mud shrimp Upogebia major in the upper sublittoral area of Vostok Bay (Peter the Great Bay, the Sea of Japan) were investigated in 2015 and 2016. Ovigerous females were found in April and May after the disappearance of the sea ice cover. Egg laying occurs only once during the breeding season. Hatching of larvae is observed in May, while in July the bottom population is replenished by a cohort of fast-growing young individuals that reach a body length of 43–44 mm during the first season of growth. In the third year of life, the females lay eggs for the first time at a body length of more than 73 mm. The females and males grow at the same rate; their growth can be approximated by a Bertalanffy equation of the form L_t = 118.4 [1–e^{–0.5627 (t + 0.5305)}]. The mud shrimp population consisted of 1–4- and, possibly, 5-year-old individuals 9–117 (females) and 8–116 mm (males) in body length. The specific features of the breeding, growth, and reproduction of the local populations of U. major are indicative of good adaptation of this species to the environmental conditions in Peter the Great Bay, which contributes to sustaining the biodiversity of the coastal zone in the region.     

Fauna of Sipunculans (Sipuncula) of Vostok Bay, Sea of Japan

Fauna and systematics of sipunculans inhabiting Vostok Bay, Sea of Japan, are discussed. A revision of the local species of sipunculans is performed for the first time. On the basis of study of outer and inner morphology, some species are reduced to synonyms. Extended diagnoses are proposed for all registered species. An identification key is presented for the sipunculans of Vostok Bay.     

The species composition and pattern of distribution of hermit crabs (Decapoda: Paguroidea) in Vostok Bay,Sea of Japan

The species composition, abundance, and vertical distribution of hermit crabs (Decapoda: Paguroidea) were investigated in Vostok Bay, Sea of Japan, from September 2014 to September 2015. A total of seven species from two families were found in the monitoring area of approximately 5000 m² located on the bottom within a depth range of 0–11 m: Pagurus minutus, P. proximus, P. brachiomastus, P. pectinatus, P. ochotensis, P. middendorffii (Paguridae), and Areopaguristes hirsutimanus (Diogenidae). Their population density varied from 22 ± 13 to 26 ± 2 ind./m²; the biomass varied from 55.76 ± 26.10 to 93.38 ± 27.00 g/m². The species composition remained invariable throughout the study period. The proportions of species abundance changed between seasons, as this parameter is largely determined by seasonal migrations of hermit crabs. Pagurus minutus predominated in number in winter and spring (up to 71%); P. proximus, in summer and autumn (up to 47%). In autumn and spring, P. ochotensis and P. pectinatus constituted a major part of biomass (18–25% and 19–20%, respectively). The proportion of a previously abundant species, P. middendorffii, was very small (no larger than 1.3%) during the study period. Another four species of hermit crabs occurred in other parts of Vostok Bay; thus, the fauna of the bay currently includes 11 species of this group.     

A new species of Hemicyclops (Copepoda, Poecilostomatoida) from burrows of the mud shrimp Upogebia major in an estuarine mud-flat in Tokyo Bay, Japan

A new species of poecilostomatoid copepod, Hemicyclops tanakai n. sp. was collected from burrows of the mud shrimp Upogebia major in an estuarine mud-flat in Tokyo Bay. The new species can be distinguished from its congeners by combination of the following characteristics: setation of the antennule, the segmentation of the antennule, the length–width ratio of the caudal ramus, the ornamentation on the third segment of antenna and the shape of the genital double somite.     

Recreational Effects in Vostok Bay, Sea of Japan

The paper presents the results of three hydrochemical surveys performed in October 2000 and May and July 2001 and microbiological monitoring performed in June, July, and August 2001 in Vostok Bay (Sea of Japan), which is a favorite recreation area for the inhabitants of Primorye and the Russian Far East. It is shown that at the height of recreation occurs during late summer, as determined by the concentration of water-dissolved oxygen, the biochemical oxygen demand (BOD₅), the concentration of detergents, and the number of colony-forming enterobacteria in 1 ml of water. However, in autumn, especially by October, the anthropogenic pressure decreases and the quality of the water environment in the bay improves.     

Arenicolous mycelial fungi from the littoral of the Vostok Bay (Peter the Great Bay,the Sea of Japan)

The taxonomic composition of marine mycelial fungi was determined in the interstitial habitats of the Vostok Bay littoral (Peter the Great Bay, the Sea of Japan). A total of 39 species of ascomycetes and anamorphic fungi were detected and identified. The predominant species of the intertidal zone were Corollospora maritima, C. lacera, Carbosphaerella leptosphaerioides, Arenariomyces trifurcatus (Ascomycota), Alternaria alternata, Scolecobasidium arenarium, and Zalerion maritimum (anamorphic fungi). The complete list of species of obligately marine ascomycetes and anamorphic fungi from the interstitial habitats of the Vostok Bay littoral is presented for the first time     

Some Data on the Composition and Distribution of the Meiofauna in Vostok Bay (Sea of Japan)

The effect of some environmental factors on the composition and spatial distribution of the meiobenthos were studied in Vostok Bay. The spatial density of the meiobenthos significantly positively correlated with ground type and was maximum in fine- grained sands. The eumeiobenthos was dominated by harpacticoids in coarse-grained ground and by nematodes in ground with a high silt content. The pseudomeiobenthos was dominated by polychaetes and bivalve mollusks in all ground types. The depth distribution of the meiobenthos was highly heterogenous, harpacticoids being the only group whose distribution correlated significantly with depth.     

A key for the identification of the zoeae of common species of hermit crabs (Decapoda: Paguroidea) of Vostok Bay,the Sea of Japan

A key for the identification of the zoeae of hermit crabs (Decapoda: Anomura: Paguroidea) in the plankton of Vostok Bay (the Sea of Japan) has been developed based on the external morphology and live coloration of the larvae. The time of hatching and the duration of occurrence of diogenid and pagurid larvae in this area have been determined.     

Progebiophilus bruscai (Isopoda:Bopyridae) parasitizing the shrimp Upogebia dawsoni (Thalassinoidea:Upogebiidae), in Baja California Sur, Mexico)]

Parasitism of the isopod Progebiophilus bruscai Salazar-Vallejo & Leija-Tristán over the common mud shrimp, Upogebia dawsoni Williams, was analysed in the Ensenada and Bahia de La Paz, Baja California Sur, Mexico. Mud-shrimps were collected in three similar sites that differ in grain size and in the anthropogenic organic matter enrichment. Four-hundred-nine mud-shrimps were collected; the largest abundance was registered in the organically enriched site, but they were significantly smaller and more heavily parasited than the animals from the site lacking such organic enrichment. The size of the parasite is clearly dependent on the size of the mud-shrimp. This is the first study of the upogebiid-bopyris relationship in Mexico.     

Retrospective analysis of the marine flora of Vostok Bay,Sea of Japan

A general list of the flora of Vostok Bay (Sea of Japan) compiled on the basis of original and literature data includes 161 species, among them 25 green algae, 42 brown algae, 90 red algae, and 4 species of seagrass. In the period from 2000 to 2004, 114 species of macrophytes (19 green algae, 29 brown algae, 63 red algae, and 3 species of seagrass) were found in Vostok Bay; 19 species of algae were first records for this bay. On the whole, the flora of Vostok Bay is dominated by warm-water species, among which Asian low-boreal species occupy the leading position. The flora of Vostok Bay is changing under the influence of global climatic and local anthropogenic factors. In recent years, there is a tendency for the proportion of warm-water species to increase. The local anthropogenic influence on the flora of Vostok Bay has caused changes in the species composition of plant communities.     

The Karyotype of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner, 1868) (Pisces: Cottidae) from Vostok Bay,Sea of Japan

For the first time, we studied the karyotype of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner, 1868) from Vostok Bay of the Sea of Japan. The karyotype is stable: 2n = 42 (2 metacentric, 2 submeta-subtelocentric, 30 subtelocentric, and 8 acrocentric chromosomes), NF = 44 + 2. The nucleolar organizers (NOs) were identified using Ag banding in two pairs of chromosomes: in the telomeric parts of the short arm of the medium-size subtelocentric chromosome and the long arm of the large acrocentric chromosome. Variations in the number of nucleolar organizer chromosomes and in the number of NO staining blocks were found. Comparison of the karyotypes of M. p. taeniopterus and previously studied M. p. platycephalus (Pallas, 1814) from the northern Sea of Okhotsk revealed their similarity in the number and morphology of chromosomes and the number of chromosome arms and difference between the subspecies in the number and location of NO, which allows their discrimination.     

Trophic Assemblages of the Rocky Intertidal Zone in Vostok Bay,Sea of Japan

The ratios between the indices of relative abundance for different trophic life forms have been used to characterize bionomical types of a rocky intertidal zone. It has been shown that the distribution of life forms is determined by the geomorphological peculiarities of the surveyed intertidal areas. A brief critical historical review has been provided of the terms bionomy and bionomical type.     

Subtidal macrobenthos communities of Vostok Bay (Sea of Japan) under conditions of anthropogenic impact

Quantitative samples of the macrobenthos were collected in May, July, and October–November from 2000 to 2002 in Vostok Bay, Sea of Japan. The main characteristics of the subtidal macrobenthos communities are described. The present study shows that the rocky bottom communities of Vostok Bay have changed little over the past 30 years. Changes have occurred in the structure of soft bottom communities and phytocenoses. Analysis of the macrophytes species composition and the value of the floristic coefficient suggest a currently moderate anthropogenic load on Vostok Bay.Original Russian Text Copyright © 2004 by Biologiya Morya, Galysheva.     

Trophic strategies and functional morphology of feeding appendages, with emphasis on setae, of Upogebia omissa and Pomatogebia operculata (Decapoda: Thalassinidea: Upogebiidae)

Although species of Upogebiidae historically have been considered filter feeders, recent studies show that many species of this group also deposit feed. In this study, the degrees of trophic specialization of two species of this family, Upogebia omissa and Pomatogebia operculata , were analysed. Feeding mechanisms, stomach contents and morphology of the feeding appendages, with emphasis on setae, were examined. U. omissa , found in sandy substrate, is a generalistic feeder while P. operculata inhabits burrows inside corals, being more specialized in filter feeding. Only 21% of the 57 setal types described were common to both species. Setal types were clustered in three main categories: plumed, serrate and plumodenticulate. No simple setae were found. P. operculata has lower setal diversity, with higher ratio of plumodenticulate to serrate setal types than U. omissa. The 1st and 2nd pereiopods have an important role in collecting food. The mouthparts have two main functions: to brush and retain particles so that food can be transported from the pereiopods to the mouth. Generally in these appendages, the dactyli and basal endites are responsible for brushing particles and the meri and coxal endites for particle retention. The diversity of setal types and complexity of their distribution on the appendages may be related to the necessity to select and triturate particles prior to ingestion, reflecting the differences in trophic strategies utilized by U. omissa and P. operculata. Setal characters appear to be indicators of the relative importance of a specific feeding mode for species of this group.     

Monitoring of phytoplankton in the area of a sea farm in Vostok Bay (Sea of Japan)

The qualitative and quantitative composition of phytoplankton in the area of a sea farm in Vostok Bay (Sea of Japan) was investigated from July 2001 to May 2002. The overall numbers of phytoplankton were 0.008 to 5.3 million cells/liter, and the biomass was 0.02 to 20.5 g/m³. The maximum density and biomass of phytoplankton were observed in summer, fall, and winter. Ten species known to be toxic were recorded. Of these, Pseudo-nitzschia multiseries (Hasle) Hasle, Alexandrium acatenella (Whedon et Kofoid) Balech, and Chattonella marina (Subrahmanyan) Hara et Chihara were found in Vostok Bay for the first time. For the diatom Skeletonema costatum (Greville) Cleve, which is an indicator of extremely eutrophic waters, the cell density was positively correlated with the area of the culture site.Original Russian Text Copyright © 2005 by Biologiya Morya, Morozova, Orlova.     

Symbiotic Crab Sestrostoma balssi (Shen, 1932) (Varunidae: Gaeticinae) from Vostok Bay, Sea of Japan: A New Species for the Fauna of Russia

A symbiotic crab Sestrostoma balssi (Shen, 1932) (Varunidae: Gaeticinae) that lives in burrows of the large ghost shrimp Upogebia major (De Haan, 1841) and U. issaeffi (Balss, 1913) (Upogebiidae) was found in Vostok Bay (Peter the Great Bay, Sea of Japan) for the first time. The occurrence of mature and juvenile specimens indicates the existence of a stable population of this species in the investigated region. This finding substantially extends the distribution area of S. balssi in the Sea of Japan.     

Vertical Distribution of the Far East Trepang Apostichopus japonicusin Vostok Bay,Sea of Japan

The abundance, weight, and age structure of aggregations of the Far East trepang Apostichopus japonicuswere studied in Vostok Bay, Sea of Japan, during the first part of September 2000. The highest density of aggregations (8.3 ± 0.5 ind/m²) and biomass (131.88 ± 10.50 g/m²) of animals was characteristic for coastal sites at the depth 0.5–1.5 m. With anincrease in depth the biomass and density of A. japonicusreduced 1.5 and 3 (depth 5–6 m), 220 and 830 times (depth 8–15 m) respectively. The ratio of large animals concurrently increased in the aggregation structure. The specifics of the distribution and spatial variability of the aggregation structure are discussed in relation to uncontrolled fishing of holothurians of large sizes.     

The Parasitic Fauna of Common Species of Hermit Crabs of Vostok Bay (Sea of Japan)

The parasitic fauna of common species of hermit crabs was investigated in Vostok Bay (the northwestern Sea of Japan). Pagurus proximus and Areopaguristes hirsutimanus had no parasites. The average prevalence of rhizocephalan infestation in other five species of hermit crabs ranged from 5.67 to 20.83%. The prevalence of the isopod Parapseudione lata on hermit crabs did not exceed 1%, the prevalence of infestation with the isopod Athelges takanoshimensis was significantly higher, reaching 14.58% in Pagurus middendorffii. Parasitism by the isopod P. lata on the hermit crabs Pagurus minutus and P. ochotensis, as well as parasitism by the rhizocephalan Peltogaster reticulata on P. minutus were recorded for the first time. Several variants of simultaneous infestation with two parasitic species were found. The decline in the abundance of P. middendorffii accompanied by the high prevalence of parasites, primarily the colonial rhizocephalan Peltogasterella gracilis, suggests that parasite invasion may play a more significant role in regulating the abundance of hermit crabs than was previously assumed.