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Morphology of the first juvenile stage of Cambaroides dauricus (Cambaroididae) and the second juvenile stage of Pacifastacus connectens (Astacidae) are described and illustrated. Morphological features of body regions, setae, and number of articles of appendages are compared with that of other species of Cambaroididae and Astacidae, respectively. For each taxon, the characteristics of the juvenile body and appendages are similar to their respective family members. The relationships between European Astacidae are examined in light of the findings.

Knowledge of the morphological features of crayfishes native to New Guinea is limited in many cases, the internal morphology, gastric mills, and mandibles of six species of Cherax species (Decapoda: Astacidea: Parastacidae) from this island were described and illustrated. The measurements were compared with those of parastacid crayfish from Madagascar and New Zealand, with Enoplometopoidea from coral reefs, and Nephropidea from deep sea. Characters peculiar to the family Parastacidae were found both in gastric mills and mandibles, and differences between the morphology of mandibles in freshwater and marine species from the infraorder Astacidea were found. Relationships between functional morphology and feeding behaviour were discussed.

Morphology in general and developmental morphology in particular provide us with an insight into the evolution, phylogeny, ecological features, behavior, and life cycle of organisms. The present study describes the external morphology of the first three postembryonic developmental stages (Stage 1­3) of two prominent European crayfish species, the noble crayfish Astacus astacus (Linnaeus, 1758) and the narrow­clawed crayfish Pontastacus leptodactylus (Eschscholtz, 1823). External morphology and setation of appendages are similar, presence of re­curved tips for cheliped in Stage I and then the tip lost in Stage 2, long plumose setae on the telson in Stage 2 and then the setae disappearance in Stage 3 accompanied with the fully developed tail fan. The number of segments on antennal flagella differs between the species in Stage I and Stage II. Observed findings on early postembryonic development are consistent between European and North American (Pacifastacus sp.) astacid species, but differ in certain aspects from other crayfish families.

Crayfish plague is a severe disease of crayfish that is caused by the oomycete Aphanomyces astaci. Two crayfish hosts of this parasite, Procambarus clarkii and Pacifastacus leniusculus, were imported from North America into Japan and were found to be infected with this parasite. Since the endemic Japanese crayfish, Cambaroides japonicus, has a low resistance to the crayfish plague, infection with this parasite will likely lead to crayfish death. Specimens of both invasive crayfish species were collected across Japan and their infection status was examined using a PCR technique. Aphanomyces astaci was detected in all localities and the average infection prevalence was 67%. Additionally, when the signs of melanization were compared with the results from PCR analyses, it suggested that the DNA detection procedure is more reliable than observation of tissue melanization. Moreover, the relationship between prevalence and water temperature in the field was analyzed, indicated that water temperature influenced the prevalence of A. astaci infection.

Crayfish are rare in the fossil record and therefore it is important to investigate each occurrence in detail. The only known fossil crayfish from France, Astacus edwardsi Van Straelen, 1928, is known from a replica made by pouring plaster of Paris inside the holotype (subsequently destroyed), an external mould extracted from a travertine cavity from the Thanetian of Sezanne. An evaluation of the taxonomic name, A. edwardsi, is provided; A. edwardsi is considered valid in accordance with ICZN rulings. It possesses atypical features for all other astacid genera, thus Emplastron gen. nov. is erected. Emplastron edwardsi gen. et comb. nov. inhabited a warm climate with calm waters, abundant food sources, and an ample supply of calcium carbonate: so much so that it is surprising that it is the only recovered specimen. Despite apparent North American faunal and floral affinities in the vicinity, E. edwardsi is more closely related to European crayfishes than it is to American ones.

The signal crayfish, Pacifastacus leniusculus, is non-native to Japan, and its invasion may have contributed to the habitat loss of the endemic Japanese crayfish, Cambaroides japonicus. We ...

Crayfishes comprise a large and diverse group of freshwater lobster-like crustaceans. Despite being abundant in the recent, they are extremely rare in the fossil record. We revise a putative occurrence of Astacus multicavatusBell, 1863 from the marine Hauterivian of Speeton Clay (Speeton, United Kingdom), which was used a few years ago as a calibration fossil representing AstacusFabricius, 1775 for divergence time analyses. This species is actually a senior synonym to Eryma sulcatumHarbort, 1905. It so appears that Eryma multicavatum (Bell, 1863) comb. nov. is not a freshwater crayfish but a marine representative of Erymidae. Two co-occurring isolated chelae, also from the Speeton Clay, may correspond to larger, older specimens of E. multicavatum comb. nov.

The Infraorder Astacidea comprises four superfamilies of decapod crustaceans: the freshwater Astacoidea and Parastacoidea and the marine Enoplometopoidea and Nephropoidea. The gill morphology of four species of crayfishes belonging to Astacoidea and Parastacoidea, two coral reef species of Enoplometopoidea, and 2 deep-water species of Nephropoidea are described and illustrated for comparisons and to determine characters characteristic to members of the family Parastacidae (Parastacoidea) from New Guinea. Morphology of the arthrobranchs and pleurobranchs were similar among all species, having a single stem with filament, but podobranchs of the parastacoideans differed from those of Astacoidea, being corrugated and tubular and having filaments. The astacoidean P. virginalis had a plate-like lamella with filament. The two nephropoid and two enoplometopoid species were similar to each other; their podobranch had a flat blade-like lamella without a filament and a shaft with a filament. The gill formulae of the New Guinea species of Cherax were the same as those of the Australian congeners, but the formula of the New Zealand Paranephrops planifronsWhite, 1842 was the same as those of the South American parastacids.

The range expansion of the red swamp crayfish (Procambarus clarkii) across Japan is reviewed and updated. A brief account of the diagnostic characters with a description of the mandible and gills of P. clarkii is provided with detailed illustrations.

Laminarialean kelps support marine ecosystems by forming marine forests as well as being used as fishery products. As the issue of decay of the marine forest increases in severity, the regeneration of kelp colonies has become a big challenge. Among various techniques used for creating kelp colonies, those that involve the dispersal of zoospores in the sea have potential for widespread use, as they do not require a lot of time, effort, and cost. When water-soluble cellulose was used as a support medium for effectively retaining Saccharina zoospores on the sea bottom, high zoospore sedimentation rates were obtained when the seawater containing the zoospores had a cellulose concentration of 0.5% or lower, and more thalli were confirmed in the sea area where the 0.5% concentration was used compared with sea areas where the 0% and 0.25% concentrations were used. When the zoospores of S. japonica var. ochotensis were dispersed (cellulose concentration: 0.5%; number of mother algae: 50 individuals; and dispersal area: ca. 890 m2) at the kelp fishing ground on the Okhotsk Sea coast of Hokkaido, eight months after the dispersal, 421 first-year thalli per 0.56 m2 were confirmed in the dispersal area compared to 47 in the non-dispersal area (both averages of two quadrats), demonstrating the effectiveness of this technique in improving a kelp fishing ground.

The genus Pacifastacus contains two subgenera, Pacifastacus and Hobbsastacus, the latter of which contains the following four extant species, Pacifastacus (H.) gambelii (Girard, 1852), P. (H.) nigrescens (Stimpson, 1857), Pacifastacus (H.) fortis (Faxon, 1914), and P. (H.) connectens (Faxon, 1914), and one fossil representative, P. (H.) chenoderma. Pacifastacus (H.) fortis and P. (H.) connectens were re-examined on the basis of the type specimens and additional materials collected from California (P. fortis) and Idaho, as well as Oregon (P. (H.) connectens), USA. Lectotypes of P. connectens and P. fortis were designated, and subsequently the two species were re-described and illustrated with their full synonymies. Brief diagnoses of P. (H.) gambelii (Girard, 1852) and P. (H.) nigrescens are also provided. Detailed distributions of these species are presented based on data from voucher specimens. Following new findings in this study, the generic diagnoses of the genus Pacifastacus and the subgenus Hobbsastacus were updated.

The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect individual-level variation in S. japonica. The STRUCTURE analysis of the SSR data identified four clusters in the species. Since the geographical distribution of these four different clusters does not correspond exactly to the currently recognized varieties in this species, it will be necessary to re-evaluate the distribution of the varieties of S. japonica.

Spread of the crayfish plague pathogen, Aphanomyces astaci, by North American crayfish species is considered one of the main reasons for substantial declines and local extinctions of native European crayfish populations. Owing to human introductions, several American crayfish species have become established throughout the world, and thus pose a potential threat to indigenous crayfish populations susceptible to crayfish plague. In Japan, two such widespread alien species, Procambarus clarkii and Pacifastacus leniusculus, were introduced for aquaculture purposes in the late 1920s and since then successfully expanded their ranges. Aggressive interactions with alien crayfish along with habitat modifications have been considered primarily responsible for drastic declines in populations of the Japanese endemic crayfish, Cambaroides japonicus, observed in the last few decades. However, the presence of the crayfish plague pathogen, to which Japanese crayfish are susceptible, may be expected, and could contribute to these declines. Only recently, A. astaci has been reported from Taiwan, and to our knowledge no study focusing on its presence outside of the Western Palearctic has been conducted. To fill this gap, 54 P. clarkii and 47 P. leniusculus individuals from five different Japanese locations were screened using molecular methods recommended by the World Organization for Animal Health. Aphanomyces astaci DNA was detected in all studied populations, altogether in 61% and 21% of examined individuals of P. clarkii and P. leniusculus, respectively. The results provide the first evidence of A. astaci presence in Japan and highlight the threat of pathogen transmission to C. japonicus populations. Copyright © 2016 John Wiley & Sons, Ltd.

The freshwater crayfish, Cambaroides japonicus, is endangered in Hokkaido, Japan and inhabits burrows. Here, we applied environmental DNA (eDNA) method for evaluating the species distributions with comparing hand-capture method in the headwater streams. We detected the eDNA of C. japonicus from all sites, where we collected C. japonicus, and confirmed that eDNA can be applied to detect burrowing aquatic freshwater crayfish without disturbing their habitats.

The taxonomy of Saccharina longipedalis, a kelp species endemic to the brackish Lake Akkeshi in eastern Hokkaido, was reviewed. The external morphology of sporophytes collected from seven sites around the distribution boundary of S. longipedalis and Saccharina japonica var. diabolica were compared; it was confirmed that the diagnostic morphology of S. longipedalis, such as a long stipe and thin blade, was not solely characteristic of individuals that grew in and around the center of the lake, which is thought to be the unique distribution area of S. longipedalis. Sequence comparisons of a 5S rDNA spacer and four microsatellite regions and AFLP analysis revealed that genetic similarity was high between S. longipedalis and S. japonica var. diabolica. Also based on observations that the early development in hybrids of sporelings from the seven sites was normal, we conclude that S. longipedalis should be treated as S. japonica var. diabolica.

Global introductions of aquatic species and their associated pathogens are threatening worldwide biodiversity. The introduction of two North American crayfish species, Procambarus clarkii and Pacifastacus leniusculus, into Japan in 1927 seems to have negatively affected native Japanese crayfish populations of Cambaroides japonicus. Several studies have shown the decline of these native populations due to competition, predation and habitat colonization by the two invasive North American crayfish species. Here, we identify an additional factor contributing to this decline. We report the first crayfish plague outbreaks in C. japonicus populations in Japan, which were diagnosed using both histological and molecular approaches (analyses of the internal transcribed spacer region). Subsequent analyses of the mitochondrial ribosomal rnnS and rnnL regions of diseased specimens indicate that these outbreaks originated from a P. clarkii population and identify a novel haplotype of Aphanomyces astaci, d3-haplotype, hosted by P. clarkii. Overall, our findings demonstrate the first two cases of crayfish plague in Japan, and the first case in a non-European native crayfish species, which originated from the red swamp crayfish P. clarkii. This finding is a matter of concern for the conservation of the native freshwater species of Japan and also highlights the risk of introducing crayfish carrier species into biogeographic regions harboring species susceptible to the crayfish plague., This research was partially supported by a grant from the Spanish Ministry of Economy and Competitiveness (CGL2016-80526-R).

Until recently, three subspecies had traditionally been recognized in the astacid species Pacifastacus leniusculus (Dana, 1852): Pacifastacus leniusculus leniusculus, Pacifastacus leniusculus klamathensis (Stimpson, 1857), and Pacifastacus leniusculus trowbridgii (Stimpson, 1857). The type specimens attributed to these taxa were re-described with detailed illustrations of taxonomic characteristics for further taxonomic works.

International audience

The history of the study of the biology of freshwater crabs is described from the first records in ancient Greece up to the present day. Today, hundreds of scientists from all parts of the world are engaged in the study of all aspects of freshwater crab biology from field studies of their ecology to molecular studies of their systematics and genetics. The first mention of the occurrence of freshwater crabs is by the Roman author Claudius Aelianus, then Aristoteles, Belon, Linne, A. Milne-Edwards, James wood-Mason, Mary Jane Rathbun, Major Alfred Alcock, Stanley Kemp, Jean Roux, Heinrich Balss, and Richard Bott in Europe developed the study.

The number of species in the three families of freshwater crayfish worldwide (Astacidae, Cambaridae, and Parastacidae) are updated by region. These are: Astacidae, western North America (5 species) and Europe (5 species), Cambaridae, eastern North America and Mexico (423 species) and Asia (6 species), and Parastacidae, Oceania (153 species), South America (12 species), and Madagascar (7 species). The conservation status of 611 species of crayfish worldwide is discussed, based on global assessments from the IUCN (International Union for Conservation of Nature) Red List protocols as well as regional assessments on governmental endangered species lists. The current threats to endangered species of crayfish include habitat destruction, water diversion, pollution, and threats from exotic species of crayfish (such as Pacifastacus leniusculus, Procambarus clarkii and Cherax) that have been introduced to other parts of the world where they are having an increasing impact. New threats posed by the parthenogenetic marbled crayfish Procambarus fallax f. virginalis to freshwater ecosystems in Europe and Madagascar are also discussed.

Deoxyribonucleic acid (DNA) fragment analysis can become an effective tool to study genetic differences between species and individuals on saccharinan kelp from which the little genetic diversity has been reported. Here, extraction methods of DNA suitable for use in analysis with a capillary sequencer is examined on Saccharina japonica var. diabolica which contains abundant polysaccharide. When amplified fragment length polymorphism was performed using genomic DNA extracted by seven different methods: (1) commercial kit, (2) original cetyl trimethylammonium bromide (CTAB) method, (3)–(5) three types of modified CTAB method, (6) modified sodium dodecyl sulfate (SDS) method, (7) combination of CTAB method and SDS method, a high reproducible peak that was suitable for analysis was noticeable in the electropherogram in the experiment with the last combination method (7). It is considered that the pretreatment washing of polysaccharide and the subsequent purification for protein and ribonucleic acid in SDS method and for polysaccharide in CTAB method are effective to obtain the high-purity DNA.

A mysterious parthenogenetic cambarid crayfish (the Marmorkrebs) has been spreading across the globe for the past decade. We compare this crayfish directly to two other cambarids, Procambarus fallax and P. alleni, that have been suggested to be related or even identical to the Marmorkrebs. Using external morphology and sequences of two mitochondrial genes we show clear correspondences between Marmorkrebs and P. fallax, a species found natively throughout peninsular Florida, USA. Based on these congruent results we suggest that the Marmorkrebs is the parthenogenetic form of P. fallax. This finding has potential evolutionary and ecological implications at several levels. The Marmorkrebs might be a type of geographical parthenogenesis, but a natural population in the wild is so far unknown. Furthermore, challenges arise in regard to the respective species status of the Marmorkrebs. Taxonomically we suggest that the Marmorkrebs is treated as ‘parthenogenetic form’ of P. fallax. Last but not least, the identity of this animal and its ecology has an impact for considering potential spread and effects of this species across the globe.

Invasion of an alien freshwater crayfish is newly confirmed in Madagascar. The invasive crayfish is determined as the parthenogenetic Marmorkrebs (marbled crayfish) (Cambaridae: Decapoda) on the basis of morphological features and the fact that all collected specimens were females regardless of their size. As this is a worrisome finding, the public should be alerted so that spread on the island can be prevented before it affects the vulnerable native crayfish biodiversity and the rice field business in Madagascar.

The syntypes of the Russian freshwater crayfish, Cambaroides schrenckii (Kessler, 1874) and Cambaroides sachalinensis (Birstein & Winogradow, 1934), that were considered lost, were recently found at the Zoological Institute of the Russian Academy of Sciences, St. Petersburg. Our re-examination has shown that C. sachalinensis is a junior synonym of C. schrenckii. A lectotype of C. schrenckii is designated, and a description is made on the basis of type material and supplemental material recently collected from the Russian Federation. Detailed information on geographic distribution of this species is provided. Morphology and behavior of juveniles, and the position of spermatophores attached to the adult females also are recorded. The phylogenetic position of this genus is evaluated based on these characteristics.

Recent studies on global climate change report that increase in seawater temperature leads to coastal ecosystem change, including coral bleaching in the tropic. In order to assess the effect of increased seawater temperature on a temperate coastal ecosystem, we studied the inter-annual variation in productivity of Laminaria japonica using long-term oceanographic observations for the Uwa Sea, southern Japan. The annual productivity estimates for L. japonica were 2.7 ± 2.5 (mean ± SD) kg wet wt. m−1 (length of rope) (2003/2004), 1.0 ± 0.6 kg wet wt. m−1 (2004/2005), and 12.1 ± 12.5 kg wet wt. m−1 (2005/2006). Our previous study using the same methodology at the same locality reported that the productivity was estimated for the 2001/2002 (33.3 ± 15.2 kg wet wt. m−1) and 2002/2003 (34.0 ± 8.7 kg wet wt. m−1) seasons. Productivity in 2003/2004 and 2004/2005 was significantly lower than in years 2001/2002, 2002/2003 and 2005/2006. A comparison of oceanographic conditions among the 5 years revealed the presence of threshold seawater temperature effects. When the average seawater temperature during the first 45 days of each experiment exceeded 15.5°C, productivity was reduced to about 10 % of that in cooler years. Moreover the analysis of growth and erosion rates indicates that when the seawater temperature was over 17°C, erosion rate exceeded growth rate. Thus, an increase of seawater temperature of just 1°C during winter drastically reduces the productivity of L. japonica in the Uwa Sea.

Section 1: New model organism for biology General Biology, Happy Birthday! The First Decade of Marmorkrebs research-Results and Perspective G. Scholtz of Humboldt University zu Berlin, Germany Conservation, Predicting the range expansion of a partenogenic crayfish invader P. Feria and Z. Faulkes of TheUniversity of Texas-Pan America, USA Experimental Biology, Marble Crayfish as A New Model Organism and A New Threat to native Crayfish Conservation Z. Faulkes of The University of Texas-Pan America, USA Physiology, Tolerance of Marbled Crayfish Procambarusfallax f. virginalis to Low Temperature in Nordic Climate K. Kaldre of Estonian University of Life Science, Estonia Reproductive biology, Parthenogenesis: Mechanisms, evolution, and its Relevance to the Role of Marbled Crayfish as Model Organism and Potential Invader P. Martin of HumboldtUniversitatzu Berlin, Germany Aquarium, Marbled crayfish Gaining Ground in Europe: the Role of the Pet Trade as invasion Pathway C. Chucholl of Fisheries Research Station BW, Germany Cell biology, Research on stem cells, Ageing, Cancer Resistance, and Epigenetics in Marbled Crayfish and Relatives: Potential Benefits for Human Biology and Medicine G. Vogt of University of Heidelberg, Germany Section 2: Crayfish: new developments Aquaculture,Developing Markets for New Product: Aquacultured Redclaw in Mexico A. Garza de Yta of CRM International S.C., Mexico The Biology of Crayfish Plague Pathogen Aphanomycesastaci: Current Answers to Most Frequent Questions J. Dieguez-Uribeondo of Royal Botanic Garden, Spain Environment, A Review of Current Techniques for Sampling Freshwater Crayfish S. Parkyn of Freshwater Ecology Consultant, Australia Behavior, Behavioral ecology of invasive crayfish: its contribution to conservation E. Tricarico of Florence University, Italy Prevent crayfish plague, Chaos and Adaptation in the Pathogen-Host Relationship in Relation to the Conservation: the Case of the Crayfish Plague and the Noble Crayfish J. Jussila, H. Kokko, and J. Makkonen of The University of Eastern Finland, Finland, Ivana Maguire of University of Zagreb, Croatia Monitoring, Crayfish as Tools in Water Quality Monitoring P. Kozak and I.Kuklinaof South Bohemian University, Czech Phylogeny, Phylogenetic Estimate of the Freshwater Crayfish (Decapoda: Astacidea) using Morphology and Molecules D. Stern and K. Crandall of The George Washington University, USA Section 3: Global overview of freshwater crayfish biology Atlantic North America, The Crayfish Fauna of Canada and the United States in North America R. Thoma, USA Middle America, The Crayfish of Middle America F. Alvarezand J. L. Villalobos of ColeccionNacional de CrustaceosInstituto de Biologia, Mexico Pacific North America, Historical Biogeography of Pacifastacuscrayfishes and their Branchiobdellidan and Entocytherid Ectosymbionts in Western North America E. Larson of University of Tennessee and B. W. Williams of Southern Illinois University, USA South America, The Native South American Crayfish (Decapoda: Parastacidae) E. Rudolph of Universidad de Los Lagos, Chile, M. P. Almerao of Federal University of Rio Grande do Sul, BI,Brazil Oceania, the Freshwater Crayfish of the Oceania Region J. M. Furseand K. L. Dawkins of Griffith University, Q. F. Burnham of Edith Cowan University, A. M. M. Richardson of University of Tasmania, Australia Africa, Crayfish of Africa C. Boyko of American Museum of Natural History, USA Europe,Crayfish in Europe: Biogeography, Ecology and Conservation L. Fureder University of Innsubruck, Austria Asia, Taxonomic Synopsis and Biology T. Kawai of Wakkanai Fisheries Institute, Japan, G. S. Min of Ina University, South Korea, E. I. Baravanshchikov of TINRO, Russia, V. S. Labay of SakhNIRO, Russia, and H. S. Ko of Silla University of South Korea Crayfish worms, Branchiobdellidans (Annelida: Clitellata), Ectosymbionts of Crayfishes S. R. Gelder of University of Main at Presque Isle, and B. W. Williams of Southern Illinois University, USA

SUMMARY Tandem repeats of the 5S ribosomal RNA gene (rDNA) were confirmed for almost all laminarian, cymathaerean and kjellmaniellan species distributed in northern Japan. The nucleotide sequence of the spacer region between tandemly repeated 5S rDNA was investigated for 79 samples from 31 sites. Phylogenetic analysis of the 29 different sequences detected revealed two lineages: (1) Laminaria coriacea group, including Laminaria coriacea Miyabe, Laminaria cichorioides Miyabe, Laminaria sachalinensis (Miyabe) Miyabe, Laminaria yendoana Miyabe, Cymathaere japonica Miyabe et Nagai, Kjellmaniella gyrata (Kjellman) Miyabe and Kjellmaniella crassifolia Miyabe; (2) Laminaria japonica group including Laminaria japonica Areschoug, Laminaria religiosa Miyabe, Laminaria ochotensis Miyabe, Laminaria diabolica Miyabe, Laminaria longipedalis Okamura, Laminaria angustata Kjellman and Laminaria longissima Miyabe. In addition, the latter group was divided into two: subgroup (2a) including L. angustata and L. longissima and subgroup (2b) including L. japonica, L. religiosa, L. ochotensis, L. diabolica and L. longipedalis. Members of the three groups differ from each other in the appearance of ornaments (bullation, gyration and folds) on the surface of the blade. These are absent in group (2a), only present in the early stages of the lifespan of group (2b), and present for the duration of the lifespan in group (1). Genetic distances among samples were extremely small within group (2a). Together with previous crossing studies and data on ocean currents and distribution, these findings suggest that gene flow occurs within group (2b).

The phylogenetic position of the four East Asian freshwater crayfish species of the genus Cambaroides is not settled. Morphological phylogenetic analyses suggest close affinities of Cambaroides with North American Cambaridae. This view is based mainly on characters of the male and female reproductive organs. In contrast, the only molecular phylogenetic analysis so far available leaves the phylogenetic position of Cambaroides unresolved. The question of whether Cambaroides is monophyletic or paraphyletic has so far been neither addressed morphologically nor with molecular data sets. Here we present the first comprehensive phylogenetic analysis of all four currently described species of Cambaroides in the framework of Northern Hemisphere freshwater crayfish (Astacoidea) relationships based on partial sequences of two mitochondrial genes (CO1 and 12S rRNA). Despite some evidence in favour of a monophyletic Cambaroides more data is needed to resolve this question. Our analyses suggest a close relationship of the North American Cambaridae and the European Astacidae, leaving the Asian Cambaroides basal to them. If these results hold true the similar reproductive organs of Cambaroides and American Cambaridae must be either homoplastic or ancestral for Northern Hemisphere Astacoidea. Zusammenfassung Die phylogenetische Beziehung der vier ostasiatischen Flusskrebsarten der Gattung Cambaroides in Relation zu den anderen Taxa der Astacoidea ist weitgehend unbestimmt. Phylogenetische Analysen morphologischer Merkmale der Reproduktionsorgane unterstutzen eine nahe Verwandtschaft von Cambaroides und den in Nordamerika lebenden Vertretern der Cambaridae. Bislang existierende molekulare Ergebnisse konnen dieses Ergebnis nicht stutzen, lassen aber die Fragen der Monophylie und der phylogenetischen Position von Cambaroides innerhalb der Astacoidea unbeantwortet. Diese Arbeit zeigt die erste umfassende phylogenetische Analyse aller vier beschriebenen rezenten Spezies der Gattung Cambaroides und ihrer phylogenetischen Beziehung innerhalb der Astacoidea, anhand zweier mitochondrialer Genabschnitte (12S rRNA und CO1). Unsere Analyse zeigt die nahe Verwandtschaft der nordamerikanischen Cambaridae und der europaischen Astacidae, wahrend Cambaroides basal zu dieser Gruppierung steht. Dieses Ergebnis lasst den Schluss zu, dass die ahnlichen Reproduktionsorgane von Cambaroides und den amerikanischen Cambaridae entweder plesiomorph fur die Astacoidea oder konvergent sind.

This is the first report of two North American branchiobdellidans, Sathodrilus attenuatus Holt, 1981, and Xironogiton victoriensis Gelder and Hall, 1990, on the signal crayfish, Pacifastacus leniusculus (Dana, 1852) introduced into Japan from the Columbia River system, northwestern North America. Signal crayfish from 12 localities in eastern and northern Hokkaido, Japan, were examined and each supported S. attenuatus. In addition, an individual of this species was found on preserved material from Ishikawa Prefecture, central Honshu. All of these branchiobdellidans reported in Hokkaido most probably came from the original population of signal crayfish introduced into Lake Mashu, Hokkaido, Japan, in 1930. It is suggested that the use of non-pathogenic branchiobdellidans, when present, provides an easy method for tracing the spread of crayfishes around Japan and could also be applied in other countries and continents. Specimens of X. victoriensis were only found on crayfish in a stream at Akashina in Nagano Prefecture, central Honshu, Japan. Although the signal crayfish appears to be displacing the endemic Japanese crayfish, C. japonicus, no native branchiobdellidans were found on any of the introduced signal crayfish examined.

KAZUYOSHI NAKATA14), KIMIHIRO TSUTSUMI2), TADASHI KAWAI3) andSEIJIGOSHIMA1) *) Laboratory of Marine Biology and Biodiversity, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan 2) Zukosha Co., Ltd., 1-17 Kita, 18 Nishi, Obihiro, Hokkaido 080-0048, Japan 3) Hokkaido Nuclear Energy Environmental Research Center, 261-1 Miyaoka, Kyowa, Hokkaido 045-0123, Japan

The spawning bed selection of herring Clupea pallasii off Minedomari, Atsuta, on the west coast of Hokkaido, Japan, is discussed in relation to the topography of the rocky shore and wave conditions during the spawning season. From 1998 to 2003, herring have spawned their eggs mainly on the leaves of the seagrass Phyllospadix iwatensis Makino in almost the same site on the rocky shore off Minedomari in the Atsuta area. The site is connected to a valley-like feature offshore. Wave conditions were surveyed at Minedomari during the spawning season in 2000 and the wave height was estimated from 1998 to 2003, except for in 2000, using the correlation of wave height between Minedomari and Ishikari Bay New Port, approximately 18 km south-west of Minedomari. Herring spawned under calm conditions, during which the wave height was approximately 0.5 m off Atusta and Aoshima and was 0.18–1.28 m off Minedomari. The distribution of water particle velocity on the sea bottom surface as a result of ocean waves off the Minedomari area, which was estimated based on the wave height and the topography of the coast, suggested herring could swim easily into the shallower area along the valley-like feature off Minedomari. Therefore, topographical features are thought to be one of the reasons why herring have used Minedomari as a spawning bed. Additionally, seepage of freshwater from the bottom, which was observed in this area, could also be the reason why herring spawn in Minedomari repeatedly.

The appropriate water velocity in artificial burrows for theJapanese crayfish species Cambaroides japonicus was studied.An experimental system of two artificial burrows (burrows A and B)of the same size was set in a large tank. The velocity of burrowA was 0 cm/s and that of burrow B was varied andset at 0 cm/s, 5 cm/s, 10 cm/s,20 cm/s and 30 cm/s. The selectionof these two burrows by C. japonicus was observed. No animalsselected burrow B significantly more than burrow A above 10 cm/s.At 20 cm/s, some crayfishes were swept away andcould not return to burrows because of the high water velocity.At 30 cm/s, most animals were swept away. We concludethat the appropriate water velocity for the suitability of artificialburrows and the immediate foraging area adjacent to the burrowsshould be as low as 5 cm/s.

Taxonomic confusion has been presented within freshwater crayfishes of the genus Cambaroides since Starobogatov published morphological definition and revision of the group in 1995. He suggested that Cambaroides should be revised: the C. dauricus contained three species C. dauricus, C. wladiwostokiensis, and C. koshewnikowi; the C. schrenckii with two species C. schrenckii and C. sachalinensis. Also Straovogatov did not take into account the previous data of crayfish distributions. In order to clear up the confusion, the taxonomy of crayfish sampled from Mongolia, Russia, China, and North Korea was reassessed. Starovogatov's key could not lead to the correct identification. Also, detailed observations of apical robe of the male first pleopod did not support the taxonomy on the genus Cambaroides proposed by Starobogatov in 1995. However, some local variations of morphology exist in rostrum, pleuron, and telson of Asian crayfish. Future studies should be concentrated on whether there are geographical dines ...

Lethal limits of high temperature were studied to clarify the effects on the survival of the endangered Japanese crayfish species Cambaroides japonicus and the alien species Pacifastacus leniusculus. After the acclimation period for 2 weeks at 16°C, the temperature was raised at a rate of 1°C per week. As a result, the ultimate upper lethal temperatures of C. japonicus and P. leniusculus were 27.0 and 31.1°C, respectively, and the lethal temperature for P. leniusculus was significantly higher than for C. japonicus. The natural distributions of these two species are discussed in terms of the temperature tolerance.

Little is known about the biology of the East Asian freshwater crayfish of the genus Cambaroides. Furthermore, the phylogenetic relationships of Cambaroides are controversial. To gain more information about East Asian crayfish and to shed some light on the phylogeny and evolution of freshwater crayfish, some aspects of the embryonic and postembryonic development of the Japanese freshwater crayfish species Cambaroides japonicus are described. The general appearance of the embryo and the growth zone consisting of about 40 ectoteloblasts correspond with the apomorphic pattern described for all other freshwater crayfish species. The occurrence of eight mesoteloblasts is a typical malacostracan character. In addition to the occurrence of freshwater crayfish apomorphies, such as a telson thread, the postembryonic development of C. japonicus follows the ground pattern of the Northern Hemisphere Astacoidea. In particular, some characteristics are in common with the postembryonic development of the Astacidae. These concern the shape of the telson of the juvenile stage 1 and the occurrence of plumose telson setae in juvenile stage 2. Furthermore, the recurved hooks of the hatchlings are lost in the juvenile stage 2, indicating an early independence of the juveniles from the mother. On the other hand, the early appearance of a spermatheca (annulus ventralis) is shared between C. japonicus and the other (American) Cambaridae. The hypothesis is developed that the evolutionary success of the different freshwater crayfish taxa might be related to the stepwise extension of maternal care as an adaptation to the freshwater environment.

The organization of 5S ribosomal RNA genes (rDNA) was examined for threeJapanese Laminaria species, L. japonica, L.religiosa and L. ochotensis. The linkage of 5SrDNA with the 18S-5.8S-25S rDNAs unit known in the brown algaScytosiphon lomentaria could not be detected inLaminaria. Instead, the tandem repeats of 5S rDNA were notassociated with the 18S-5.8S-25S rDNAs unit. The nucleotide sequence of 5S rDNAwas completely identical among these three species and its length was 118bp. However, a difference of nucleotide arrangement was detectedinthe spacer region of the tandemly repeated 5S rDNAs. Several nucleotideinsertion / deletions and substitutions were confirmed between differentindividuals of L. japonica, which were collected from notonly disjunct localities, but also the same locality. The lengths of the spacerregion of L. japonica, L. religiosaand L. ochotensis were 247–252 bp, 232bp and 252 bp, respectively.

Random amplified polymorphic DNA (RAPD) was studied to detect genetic markers for three economically important Japanese laminarian species, Laminaria japonica Areschoug, L. religiosa Miyabe and L. ochotensis Miyabe, which were sampled from their representative localities on the coasts from Tsugaru Straits to the Sea of Japan. DNA templates for RAPD were extracted from lamina using a DNA extraction kit and were purified with glassmilk. Reproducible RAPD markers for these three species were detected using three random primers from a total of 15 tested. In L. japonica and L. religiosa, these RAPD markers were confirmed to be useful for populations from other localities. The three species studied showed high intraspecific and interspecific band sharing index (BSI) values. Like annual typical L. religiosa from other localities, biennial individuals identified as putative L. religiosa from Atsuta could be discriminated from L. japonica but not from L. ochotensis by any of the RAPD genetic markers studied so far.

SUMMARY: Preference for artificial burrows by the endangered Japanese crayfish species Cambaroides japonicus was studied to improve its cultivation. The occupation of artificial burrows, which were made from straight polyvinyl chloride pipes of different internal diameters (Y, mm), by crayfishes of different total lengths (X, mm) was significantly (P < 0.001, n = 56) described by a linear regression: Y = 0.49X + 3.42 (19.0 ≤X≤ 70.2). Among burrows of different lengths [crayfish total length (TL) × 1, × 2, × 3, and × 4], crayfishes significantly preferred burrows that were greater than TL × 3 (P < 0.001, n = 588).