A Finding of the Crab Planes marinus Rathbun, 1914 (Decapoda: Grapsidae) in Peter the Great Bay,Sea of Japan

A crab Planes marinus Rathbun, 1914 was found on a drifting buoy in Peter the Great Bay (Sea of Japan). The crab probably arrived in the bay with subtropical waters penetrating into this area during the summer period.     

Fouling community of the red king crab, <Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis> (Tilesius 1815), in a subarctic fjord of the Barents sea

We examined the species composition of red king crab (Paralithodes camtschaticus) fouling communities in Dolgaya Bay, a small fjord of the Barents Sea, in August 2005 and 2006. In total, there were 13 species observed on 301 crabs collected from water depths of 5–90 m. Barnacles (Balanus crenatus; prevalence 42.9%) and blue mussels (Mytilus edulis; 11.6%) were the most common epibionts, while amphipods (Ischyrocerus commensalis) were the most common symbionts (28.6%). Infestation rates in Dolgaya Bay were different from those in an “open” area of the Barents Sea (Dalnezelenetskaya Bay), probably due to differences in hydrodynamic conditions. Differences in infestation prevalence and intensity were detected neither between male and female crabs nor between crabs collected at 5–35 m versus 90 m depths. Prevalence of common fouling species increased with host size. Amphipods I. commensalis colonized the carapace and limbs in Dolgaya Bay less frequently than in Dalnezelenetskaya Bay, probably due to interspecific competition with barnacles occupying the dorsal parts of the host. Juvenile barnacles and mussels dominated the fouling communities on the crabs. The age of barnacles did not exceed 2–4 months. However, the presence of 4-year-old mussels suggests that these older mollusks have been directly transferred from mussel beds to the hosts. Our results indicate that colonization by epibionts and symbionts is generally not disadvantageous for the crab hosts, except for some possible negative impacts of amphipods occupying the gills.     

The period of occurrence,density, and distribution of larvae of three commercial crab species in Peter the Great Bay,Sea of Japan

Based on materials from plankton surveys carried out in 2004–2009, the period of occurrence, density, and distribution of larvae of three commercial species of crabs in the Peter the Great bay and adjacent areas of Sea of Japan were studied. The larvae of the horsehair crab Erimacrus isenbeckii (Brandt, 1848) occurred in the plankton from mid-March to early June, within the range of water temperature from −1 to 10.8°C. The larvae of the helmet crab Telmessus cheiragonus (Tilesius, 1812) appeared in the plankton in mid-April and occurred to the end of June within the temperature range from 2.8 to 13.0°C. The larvae of the snow crab Chionoecetes opilio (O. Fabricius, 1788) appeared in the plankton in mid-April as well, but some individuals sporadically occurred until early August. All the species of crabs produced one generation of larvae for their reproduction season. The terms of larval stay in plankton depended on water temperature and the duration of the pelagic period increased in colder years. In that area, the larvae of C. opilio were the most abundant (up to 41 ind./m³) and the zoea density of horsehair and helmet crabs was significantly lower (no more than 2 ind./m³). The larvae of C. opilio occurred over the entire area of the Peter the Great bay; the greatest aggregations of their early stages were observed in its southwestern open part. The maximum density of E. isenbeckii zoea was recorded in the south of the Amursky bay and in the Posyet bay. Individual larvae of T. cheiragonus occurred in the Posyet bay and in the southern part of the Amursky and Ussuriisky bays. The late-stage larvae of all crab species were concentrated in areas of the coastal circulation.     

Estimation of foraging on the sea urchin <Emphasis Type="Italic">Strongylocentrotus droebachiensis</Emphasis> (Echinoidea: Echinoida) by the red king crab <Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis> (Malacostraca: Decapoda) in coastal waters of the Barents Sea

A new method for the estimation of foraging on the sea urchin Strongylocentrotus droebachiensis (O.F. Müller, 1776) by the red king crab Paralithodes camtschaticus (Tilesius, 1815) is proposed. This method uses the reconstruction of the size, number, and biomass of eaten sea urchins, based on fragments of their teeth and tests from the crab’s digestive tract. Data obtained by this method suggest that in shallow waters of the Barents Sea (Kola Bay, Dal’nezelenetskaya Bay) adult, most often, female and immature crabs predominantly consume juvenile sea urchins. The weight of sea urchins daily eaten by one adult red king crab was 0.2–8.0% of its body weight for sexually mature crabs and 3.0–28.0% for immature specimens. Damage inflicted to the S. droebachiensis population as a result of the crab feeding activity was estimated to be at least 10% of the sea urchin biomass in Dal’nezelenetskaya Inlet and at least 30% in Kola Bay.     

Discovery of larvae of the hermit crab <Emphasis Type="Italic">Diogenes nitidimanus</Emphasis> Terao, 1913 (Decapoda: Diogenidae) in ship ballast waters: Evidence in support of its introduction into Peter the Great Bay

The larva of the hermit crab Diogenes nitidimanus Terao, 1913 was found in the ballast waters of the tanker Minotaur that arrived from the Chinese port of Laizhou (Bohai Bay, Yellow Sea). Earlier, an abundant population of mature adults of D. nitidimanus was found in Vostok Bay (Peter the Great Bay), this suggested the introduction and naturalization of this species in the Peter the Great Bay. The finding of its larva in ballast waters of a ship on the Russia-China route confirms the introduction of this species into Peter the Great Bay.     

Pollution in Peter the Great Bay, Sea of Japan, and its biological consequences

This review summarizes information published in the 1980s–1990s about anthropogenic pollution in Peter the Great Bay, the largest of the bays in the northwestern part of the Sea of Japan. The coastal zone of the bay occupies about 12% of the area of Primorskii Province and is the most heavily populated. The bulk of the human settlements, the seaports of Vladivostok and Nakhodka, railways, industrial enterprises, and developed agriculture are located in the coastal zone. Sewage waters containing multicomponent mixtures of polluting agents of both mineral and organic origin are discharged into the coastal waters of the bay. This paper presents information about the concentration of major classes of polluting agents (oil hydrocarbons, polychlorinated hydrocarbons, surfactants, heavy metals, and radionuclids) in the water and bottom sediments of the bay. The results of physico-chemical and biogeochemical investigations performed in the 1970s–1990s justify considering Zolotoi Rog Bay, Bosfor Vostochnyi Strait, Nakhodka Bay (especially its innermost portion, around the harbor of Nakhodka), and Amurskii Bay to be the most polluted areas in Peter the Great Bay. The information about the biological consequences of pollution in these water areas is briefly reviewed.     

Epibionts of the red king crab Paralithodes camtschaticus (Tilesius, 1815) in Sayda Inlet of Kola Bay

The species composition of organisms associated with the red king crab Paralithodes camtschaticus (Tilesius, 1815) was investigated in Sayda Inlet of Kola Bay in 2004–2005. Nine fouler species and three symbiotic species were found on the carapaces of the red king crab. Balanus crenatus Bruigere 1789 barnacles were the most abundant fouler species and were found on 14.8% of the crabs. Symbiotic amphipods Ischyrocerus commensalis Chevreux, 1900 were found for one-tenth of all the crabs studied. The mean intensity of the amphipods was significantly greater for September, when the reproduction period of this species occurred. Male and female crabs were hosted with the same intensity. The number of host crabs increased accordingly to the crab size. The proportion of hosted crabs was three-fold less in Sayda Inlet than in the less polluted areas of the Barents Sea.     

Distribution and some features of biology of sea raven <Emphasis Type="Italic">Hemitripterus villosus</Emphasis> (Hemitripteridae) in the northwestern part of the Sea of Japan

On the basis of long-term (1981–2008) observations, it was shown that, in the northwestern part of the Sea of Japan, sea raven Hemitripterus villosus is a common species with low, but stable numbers and it is a part of elittoral ichthyocenoses. During the year it performs wintering, feeding, and spawning migrations within the shelf and the upper part of the continental slope occurring from almost the water’s edge to a depth of 550 m. Highest density of sea raven is observed in Peter the Great Bay and the lowest is observed off the coasts of northern Primorye. Maximum length of H. villosus in the northwestern part of the Sea of Japan reaches 57 cm, and the modal group of fish consists of fish with a length of 25–45 cm (75%). In Peter the Great Bay, in the summer period, individuals with a length of 11–50 cm feed mainly on mass fish species; the value of daily ration of H. villosus varies from 1.6 to 3.2% of body weight, averaging 2.5%. According to an expert estimate, the biomass of sea raven in the northwestern part of the Sea of Japan reaches 2000 t.     

Peculiarities of reproductive biology and larval development of the red king crab <Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis> in Peter the Great Bay,Sea of Japan

Based on materials from trawling (2002–2005) and plankton (2004–2006) surveys, some problems of the reproduction biology of the red king crab Paralithodes camtschaticus (Tilesius, 1815) population from Peter the Great Bay are considered. It was shown that the width of the carapace varied from 105 to 190 mm in female red king crabs with eggs; 50% of the females reached maturity with a carapace width of 112.8 mm. The average individual absolute fecundity of females was 200000 (114000–296000) eggs. A direct linear correlation between fecundity and female carapace width was recorded. The zoeas I–IV of the red king crab occurred in the plankton from the middle of April up to the end of the second decade of May at water temperatures from 2.8 up to 9.3°C. The periods of larval occurrence in plankton in various years correlated with the water temperature, with a temperature decrease, the duration of the pelagic period increased. No direct correlation was revealed between the phytoplankton bloom and larval release. The density of red king crab larvae in Peter the Great Bay did not exceed 0.02–13.3 spec./m³. The maximum concentration of zoeas was recorded in the central part of Ussuriysky Bay.     

Impact scenario for the invasive red king crab <Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis> (Tilesius, 1815) (Reptantia,Lithodidae) on Norwegian,native, epibenthic prey

Large invasive predators like the king crab, Paralithodes camtschaticus, deserve particular attention due to their potential for catastrophic ecological impact on recipient communities. Conspicuous, epibenthic prey species, such as the slow growing commercial scallop Chlamys islandica, are particularly exposed to the risk of local extinction. A research program integrating experiments and field monitoring is attempting to predict and track the impact of invasive king crab on scallop beds and associated fauna along the north Norwegian coast. The claw gape of the crab shows no limitations in handling the flat-bodied scallop. However, the potential impact of the crab on scallop may depend on the availability of other calcified prey associated with scallop beds, such as the sea star, sea urchin, and blue mussel, all species recorded in the diet of P. camtschaticus. To address this issue, a laboratory experiment on foraging behaviour of P. camtschaticus was conducted. The experimental results show that all size classes of red king crab prefer scallops, but small juveniles and medium sized crabs demonstrate active selection for starfish (Asterias rubens) that equals or surpasses the electivity of the large crab. The selection of sea urchin (Strongylocentrotus droebachiensis) and blue mussel (Mytilus edulis) is slightly positive or neutral for the three crab size classes. These results suggest that scallop beds with a rich associated fauna are less vulnerable to red king crabs predation and possibly more resilient than beds with few associated species. Also, crab size distribution is likely relevant for invasion impact, with increasing abundance of small and medium sized crabs being detrimental for alternative calcified prey associated with scallop beds. Successive stages of crab invasion will see an acceleration of scallop mortality rates associated with (i) decreasing availability of alternative prey, due to protracted predation pressure intensified by recruitment of juvenile crabs, and (ii) increased number of large crabs. Estimates of crab density and intake rates suggest that the accelerated loss rates will eventually endanger scallop beds persistence.     

Species composition,seasonal dynamics of quantities and spatial distribution of hydromedusae (Cnidaria: Hydrozoa) in Vostok bay of the Sea of Japan

Hydromedusae (Cnidaria: Hydrozoa) are one of the most common and widely spread plankton organisms. Due to their low quantities in the plankton and complicated species identification, they are poorly observed in zooplankton research works, especially in the Northwestern part of the Sea of Japan. The subjects of the present work are the seasonal dynamics of the spatial distribution and abundance of hydromedusae that inhabit Vostok bay (Peter the Great bay of the Sea of Japan), which were observed from April to November in 2002–2004. The timing of mature specimens was studied for different species. Eighteen species were found. Of these, Coryne sp., Tiaropsis multicirrata (Sars, 1835) and Neoturris breviconis (Murbach et Shearer, 1903) are the first records for Peter the Great Bay; the last two species are the first records for the Northwestern part of the Sea of Japan.     

Fauna of Sponges (Porifera) of Peter the Great Bay,Sea of Japan

A complete list of sponges of Peter the Great Bay (northwestern Sea of Japan) is presented comprising 40 species belonging to 27 genera, 19 families, 9 orders, and 2 classes. Information is presented about the biogeographical composition of sponge fauna of the bay, the depths of their habitats, and their substrates.Original Russian Text Copyright ¢ 2005 by Biologiya Morya, Khodakovskaya.     

Impact Scenario for an Introduced Decapod on Arctic Epibenthic Communities

The intentional introduction of a species for the enhancement of stock or establishment of new fisheries, often has unforeseen effects. The red king crabs, Paralithodes camtschaticus, which was introduced into the Barents Sea by Russian scientists, has established a self-sustaining population that has expanded into Norwegian waters. As top benthic predators, the introduced red king crabs may have possible effects upon native epifaunal scallop (Chlamys islandica) communities. These benthic communities may be a source of prey species in late spring, when the red king crabs feed most intensively. Foraging rates (consumption, killing or severely damaging) of red king crab on native prey organisms were measured by factorial manipulation of crab density (0.5, 1.5 and 3 per m ²), size classes (immature, small mature, and large mature crabs), and by evaluating prey consumption after 48 h, in order to extrapolate a scenario of the likely impacts. Foraging rates of the red king crab on scallops ranged between 150 and 335 g per m² within 48 h. These rates did not change when crab density was altered, though an increased amount of crushed scallops left uneaten at the tank floor, were correlated with high density of small mature crabs. Foraging rate changed significantly with crab size. Consequently, the susceptibility of native, shallow water epibenthic communities to red king crab predation in the early life history stages, and during the post-mating/molting spring period, must be considered significant when foraging rates are contrasted with natural scallop biomass between 400 and 1200 g scallops per m².     

Microsporidia of the genera <Emphasis Type="Italic">Thelohania</Emphasis> (Thelohaniidae) and <Emphasis Type="Italic">Ameson</Emphasis> (Pereziidae) in two species of lithodid crabs from the Sea of Okhotsk

Diseases caused by microsporidia were found in the red king crab Paralithodes camtschaticus and the blue king crab P. platypus that inhabit the Sea of Okhotsk. Based on the histological features of the invasion and data on the morphological structure of the parasites, the microsporidia were assigned to the genera Thelohania and Ameson. Infected crabs exhibited severe destructive changes of their internal organs along with sharply pronounced external signs of disease. During the observation period, the microsporidian invasion was only found in females and young (unmarketable size) males from August to mid-October. Later, until mid-December, no diseased crabs were found.     

Infestation Level of the Crab Hemigrapsus sanguineus by a Parasitic Crustacean Polyascus polygenea (Crustacea: Cirripedia) in Vostok Bay, Sea of Japan

We studied the infestation level of the coastal crab Hemigrapsus sanguineus by a cirripede barnacle Polyascus polygenea in Peter the Great Bay (Vostok Bay, Sea of Japan) in 1998–1999. It is shown that the externae of the parasite usually appear on the surface of the host’s body at the time when the crab attains sexual maturity (at a carapace width of 14–15 mm). More often we encountered infested crabs of a medium size, with a carapace width of 25–29 mm. The level of crab invasion did not depend on the sex of the host. In the summer period the proportion of infested crabs in different habitats ranged from 7 to 84%. The greatest number of crabs bearing the externae of the parasite was registered in an area with a boulder-pebble surface and small surf waves.Original Russian Text Copyright © 2005 by Biologiya Morya, Korn, Akhmadieva, Rybakov, Shukalyuk.     

Hemolymph molting hormone concentrations in red king crabs from the Barents Sea

Recent declines in red king crab (Paralithodes camtschaticus) stocks in its native and introduced habitat have sparked interest in the development of aquaculture methods for this commercially important species. Little is known about the basic biology of this species and the factors controlling its growth rate. In this paper we present concentrations of circulating ecdysteroids (the hormones that control molting) in hemolymph of intermolt red king crabs in three coastal areas of the Barents Sea. Two molting hormones (20-hydroxyecdysone and ecdysone) were assayed. Mean levels of these ecdysteroids varied from 0.0 to 190.0 μg ml⁻¹ and from 0.0 to 13.4 μg ml⁻¹, respectively. These levels in general were higher in comparison with other decapod species. Concentrations of ecdysteroids were similar in male and female crabs and in injured (animals with at least one autotomized limb) and intact red king crabs. In contrast, the levels of circulating ecdysteroids were much higher in small (predominantly immature crabs) than in large adult animals because the latter have a lower molting probability (once per year) than smaller crabs (2–3 times per year). Our data can be used in further investigations of red king crab growth rates and their application to the development of aquaculture methods for this species.     

Walking speed and area utilization of red king crab (<Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis>) introduced to the Barents Sea coastal ecosystem

The red king crab (Paralithodes camtschaticus) was introduced in the Barents Sea in the 1960s and soon established a viable population. Proper management and exploitation of the Barents Sea king crab stock require better understanding of the spatial dynamics at different scales. This study examines the small-scale movement patterns of seven adult male crabs tracked for a period of up to one month from mid July to mid August at 150 m depth in a semi-enclosed fjord on the Russo-Norwegian border. The crabs were tagged with acoustic transmitters and their movements monitored with an acoustic positioning system. Low walking speeds (<0.01 m s⁻¹) were most frequent but the crabs could move at a maximum speed of 0.15 m s⁻¹ and walk an actual distance of up to 270 m over a period of one hour. However, the crabs usually moved within a relatively restricted area with mean hourly longest rectilinear distance varying from 26 to 64 m. The crabs alternated between periods of low and high activity, which could reflect feeding in and movements between food patches. The lack of a diel activity rhythm may be due to high light levels during the polar summer night, or a chemically mediated food search strategy.     

Epifauna associated with the northern stone crab <Emphasis Type="Italic">Lithodes maia</Emphasis> in the Barents Sea

Species composition, prevalence, and intensities of species colonizing the northern stone crab Lithodes maia in Dalnezelenetskaya Bay (Barents Sea) were examined. Sixteen species attached to the body surface or the host gills were identified. The most common associates were hydrozoans (100.0%), especially Obelia longissima, and the amphipods Ischyrocerus commensalis (93.8%). Species composition of the stone crab epifauna was similar to that observed for the Lithodid crab Paralithodes camtschaticus, except that tubular polychaetes Pomatoceros triqueter and Placostegus tridentatus were found only on the surface of the stone crab, while fish leeches Johanssonia arctica occurred on the red king crabs. Differences in percentage of infested hosts, and mean intensities of some associates are influenced by the conditions of carapace structure and size of both crab species.     

Development of microsatellite loci in red king crab (Paralithodes camtschaticus)

Polymerase chain reaction (PCR) primers for three trinucleotide and three tetranucleotide microsatellite loci were developed for red king crab (Paralithodes camtschaticus) to aid in studies of genetic population structure in Alaskan waters. Number of alleles ranged from six to 18 alleles (N = 562), and locus heterozygosities ranged from 0.505 to 0.839. Six primers were cross amplified with golden king crab (Lithodes aequispinus); five primers with blue king crab (P. platypus); and one primer with the splendid hermit crab (Labidochirus splendescens), the ‘missing link’ between pagurid and lithodid crabs. No cross amplification occurred with Tanner crab (Chionoecetes bairdi) or Aleutian hermit crab (Pagurus aleuticus).     

Hermit crabs Pagurus parvispina Komai, 1997 and Discorsopagurus maclaughlinae Komai, 1995 (Decapoda: Paguridae): New records for Russian waters of the Sea of Japan

The hermit crab Pagurus parvispina Komai, 1997 (Decapoda: Paguridae) was found in Vostok Bay (Peter the Great Bay, Sea of Japan) at a depth of 50?C65 m. Earlier, this species was recorded from the type locality in northern Japan at a depth of 150?C200 m. The finding of P. parvispina in Vostok Bay is its first record in Russian waters and substantially expands the distribution area of this species in the Sea of Japan. Discorsopagurus maclaughlinae Komai, 1995 inhabits Russian waters and was earlier identified as Orthopagurus schmitti (Stevens, 1925); its taxonomical position is discussed.