Paralithodes Brevipes Research Articles

First detection of Hematodinium sp. In spiny king crab Paralithodes brevipes, and new geographic areas for the parasite in tanner crab Chionoecetes bairdi, and red king crab Paralithodes camtschaticus

A parasitic dinoflagellate of the genus Hematodinium was found off the Pacific coast of Kamchatka in three species of crabs: red king crab Paralithodes camtschaticus, tanner crab Chionoecetes bairdi, and spiny king crab Paralithodes brevipes. This is the first detection of Hematodinium in spiny king crab. The results of the genetic analysis showed that the pathogen found in P. brevipes, P. camtschaticus, and C bairdi from the Avacha and Kronotsky bays off the Pacific coast of Kamchatka was the same or very close to the Hematodinium sp., which infects many species of crustaceans in the Northern Hemisphere. The prevalence of infection was 0.2% for tanner crabs and 2.7% for red king crabs. Due to a limited sample size, we were unable to calculate the prevalence for spiny king crabs and female red king crabs. Both the macroscopic and microscopic signs of the pathology were similar in all diseased crabs. The differences in the micromorphology of the Hematodinium cells we found in the three crab species, including the presence or absence of trichocysts, the shape of the plasmodia, and the structure of pore complexes, are most likely related to the life cycle and the physiology of the parasite. The results of the genetic analysis showed that the pathogen found in P. brevipes, P. camtschaticus, and C. bairdi from the Avacha and Kronotsky bays of the Pacific coast of Kamchatka was the same or very close to the Hematodinium sp., which infects many species of crustaceans in the Northern Hemisphere.

Life without ice: Perceptions of environmental impacts on marine resources and subsistence users of St. Lawrence Island

The Bering Strait region is undergoing rapid environmental change linked to reductions in the extent and seasonal availability of sea ice. The goal of the present study was to assess the impacts that environmental change and loss of sea ice has had on marine subsistence resources and resource users in the communities of St. Lawrence Island (SLI), Alaska. The broader research design was multidisciplinary in order to document any shifts in the abundance and health of key marine subsistence species, while recording people's perceptions of changing environmental conditions in their lifetime. The present study focuses on the perceived social and material effects of climate change on SLI residents. To capture human perceptions and experiences, open ended interviews were conducted during three weeks in April and May 2019, during which time 25 SLI residents were interviewed. Four main themes were assessed: 1) key marine resources for SLI communities, 2) perceptions about changes in key resources, 3) community responses to change, and 4) the future of the subsistence way of life in these communities. Interviews were transcribed, coded for themes, and analyzed using MAXQDA software. Results indicate the four most discussed marine resources were Pacific walruses (Odobenus rosmarus divergens), seals, crabs, and fish. The largest changes observed in these resources included: decreased walrus harvests and limited access with increased hunting effort; an increase in the abundance of Hanasaki crab (Paralithodes brevipes) and limited crab harvests due to lack of shorefast ice; and increasing abundances of walleye pollock (Gadus chalcogrammus) and Pacific cod (Gadus macrocephalus). SLI residents utilize a broad range of edible marine flora and fauna, and at times, eat less desirable prey items due to scarcity of preferred species. Lastly, most informants that discussed the future of a subsistence way of life, were concerned future generations will be harvesting and eating less subsistence resources. Due to environmental changes, and most specifically loss of sea ice, SLI communities may have to diversify the species that they harvest to continue maritime subsistence practices, or may turn to consuming more terrestrial and domestic sources of protein if available. To better understand resource availability and to manage for a changing ecosystem, resource managers and policy makers may: 1) anticipate a need for conducting stock assessments for king and Hanasaki crabs at regular intervals, 2) anticipate a need for conflict resolutions, mitigation frameworks, or agreements if commercial fishing vessels encroach on space and resources traditionally used by SLI subsistence users, and 3) take an active approach in obtaining authorizations for the harvest of currently protected marine mammals, which may be needed to ensure food security and consumption of historically traditional foods from the local environment.

Microstructures of crab chela: A biological composite for pinching

We have investigated the microstructures and mechanical properties of four crab species Paralithodes brevipes, Eriocheir japonicas, Geothelphusa dehaani, and Telmessus acutidens and analyzed the molecular and elemental data of their chela. In the visible brown region (BR) at the distal end of the dactylus tip in Paralithodes brevipes and Eriocheir japonicas, the elastic modulus and calcium (Ca) content were lower than in the white region (WR). Near the interface between BR and WR, Ca, and carbon (C) composition changed continuously. Molecular analysis shows that the dactylus tips of the chela in P. brevipes and E. japonicas were composed of chitin and calcium carbonate. In G. dehaani and T. acutidens, the Ca concentration was homogeneous in the top portion (TP) of the dactylus dentitions. The lowest value of Ca concentration was found near the surface of the bottom portion (BP) on the dactylus dentitions. In G. dehaani, the elastic modulus distribution in the TP was maximum near the outermost surface, and gradually decreased in the inner layers; the lowest elastic modulus in the BP was near the outermost surface, and the distribution increased in the inner layer. These results show that the biological composite was as a continuous structure near the interface of the dactylus tip. Understanding the microstructures of the dactyla of crabs might help the study and development of bio-inspired composites for pinching.

SPECIES COMPOSITION AND DISTRIBUTION OF MACROEPIBENTHOS IN THE COASTAL ZONE OF THE NORTHWESTERN TATAR STRAIT

Dredgе survey (177 stations) was conducted in the northwestern Tatar Strait (northward from 48° N) at the depths 14–82 m in summer 2018 (from July 21 to August 7). In the dredge catches, 76 species and taxa of benthic invertebrates are recorded, including 42 epibenthic species, mainly Ophiura sarsi, Evasterias echinosoma, Strongylocentrotus pallidus, Paralithodes brevipes, Cucumaria japonica, P. camtschaticus, Mizuhopecten yessoensis, and S. intermedius. The areas of their aggregations are determined. The largest area was occupied by the settlements of polyphagous S. pallidus (5100 km22 at the depths 30–60 m). Specific biomass of epibenthos is calculated, its average value within the surveyed area was 21.5 ± 2.0 g/m2. Depth ranges of the species domination are defined. The dominant species changed with latitude: in the southern part of the survey, Paralithodes camtschaticus dominated with the biomass of 5.1 ± 4.4 g/m2 in the upper 20 m layer (48–49° N), replaced at the depth of 20–30 m by P. brevipes (22.2 ± 14.2 g/m2 between 48–49° N) or C. japonica (28.2 ± 3.0 g/m2 between 49–50° N), both species changed deeper to S. pallidus (4.3 ± 1.1 g/m2); in the northern part of the survey (50–51° N), S. intermedius dominated in the upper 30 m layer with the biomass of 14.7 ± 9.5 g/m2, Mizuhopecten yessoensis (9.7 ± 6.2 g/m2 ) and Evasterias echinosoma (5.1 ± 1,0 g/m2 ) prevailed in the depth range of 30–40 m and were replaced by S. pallidus (18.0 ± 9.5 g/m2) below 50 m; in the northernmost shallow tip of the Strait, Ophiura sarsi dominated absolutely with the biomass of 13.0 ± 1.1 g/m2) in the whole depth range down to 30 m. The greatest species richness and abundance of epibenthos were observed at the depths not exceeding 40 m. Statistically significant decreasing of quantitative parameters of the epibenthos with the depth is observed because of the bottom temperature and topical diversity declination with depth. However, environmental conditions have no significant impact on latitudinal distribution of abundance, wealth and species diversity of the epifauna in the surveyed area. The grouping of epibenthos with specific species structure that could be classified as the circumlittoral one is defined in the upper shelf zone in the northernmost area with the depth < 30 m (somewhere < 40 m).

Impacts of Large Male-Selective Harvesting on Reproduction: Illustration with Large Decapod Crustacean Resources

To signal a need for caution for present large male-selective harvesting practices, negative impacts of the large male-selective harvesting on reproductive output in large decapod crustacean resources are introduced with emphasis on my own work with spiny king crab Paralithodes brevipes, coconut crab Birgus latro, and the stone crab Hapalogaster dentata. The large male-selective harvestings for several large decapod crustaceans have changed their population demographic structure by decreasing mean male size and skewing sex ratio towards females. By several field and laboratory experiments, the change of population demographic structure was anticipated to decrease female reproductive success in the resources (i.e. reproductive output of the harvested populations) through a decrease in sperm availability for females because of male size-dependent reproductive potentials and slow sperm recovery rate. Furthermore, reproductive output and stability of the large male-selective harvested resources were also anticipated to decline by a decrease in mate availability for females, attributing to combination of female mate choice for larger males with negative effects of female delayed mating and/or maternal influences. To establish the optimal management practices, the details of the mating system and reproductive ecology of each targeted species should be investigated.

ハナサキガニに関する根室市とサフニロとの共同研究「ハナサキ・プログラム」 FY2004-2009 が終了

ハナサキガニに関する根室市とサフニロとの共同研究「ハナサキ・プログラム」 FY2004-2009 が終了

Does male-only fishing influence reproductive success of the female spiny king crab, Paralithodes brevipes?

Male-only fishing for spiny king crab (Paralithodes brevipes) has likely impaired the reproductive success of the stock by decreasing the availability of sperm and (or) male mates. The reproductive success of females in fished populations in 2003 and 2004 was estimated based on female reproductive potential determined in laboratory experiments. Some females had no or partial clutches and showed a low fertilization rate. As female size decreased, the fertilization rate decreased and their clutches became small. These results suggest that mating was impaired by sperm limitation, because risk of sperm limitation increases throughout the reproductive season in fished populations, and smaller females tend to mate later in the reproductive season than larger females of this species. We compared the reproductive success between these years with different fishing pressures. In 2003, the total fishing pressure was high, therefore causing decreases in availability of sperm and males. This likely resulted in the reproductive success of females being lower in 2003 than in 2004.

2,3′‐Dihydroxycanthaxanthin (I), a New Carotenoid with a 2‐Hydroxy‐4‐oxo‐β‐end Group from the Hermit Crab, Paralithodes brevipes.

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Variation of sperm allocation with male size and recovery rate of sperm numbers in spiny king crab Paralithodes brevipes

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 312:189-199 (2006) - doi:10.3354/meps312189 Variation of sperm allocation with male size and recovery rate of sperm numbers in spiny king crab Paralithodes brevipes Taku Sato1,*, Masakazu Ashidate2, Tadao Jinbo2, Seiji Goshima1 1Laboratory of Marine Biodiversity, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan 2IAA, FRA, National Center for Stock Enhancement, Akkeshi Station, 2-1 Tsukushikoi, Akkeshi, Hokkaido 088-1160, Japan *Email: takyun@mail.goo.ne.jp ABSTRACT: This study examined whether sperm allocation by males can limit sperm passed to females in fished spiny king crab populations in which large males are selectively fished. We investigated the recovery rate of sperm in vasa deferentia of males of different body sizes, sperm allocation passed to females of different body sizes by males of different body sizes, and sperm allocation in different male:female sex ratios (1:1 or 1:6) by males of different body sizes by laboratory experiments. The recovery rates of sperm were very slow regardless of male size, suggesting that a sperm allocation strategy is important to increase male reproductive success in this species. In large males, the ejaculate size increased significantly with increasing female size, but the ejaculate size of small males did not vary with female size, indicating that small males cannot increase ejaculate size by more than a certain number. Females mated with small males showed significantly lower fertilization rates than females mated with large males. Males showed no difference in pattern of sperm allocation between the different sex ratios in both male size classes. These results suggest that a decrease in mean male size due to male-only fishing would increase the number of females mated with small males without an ability to increase ejaculate size with increasing female size, which would result in females mating with small males would receive an insufficient sperm supply and have a low fertilization rate due to sperm limitation. KEY WORDS: Sperm limitation · Sperm allocation · Sperm-to-egg ratio · Recovery rate · Male-only fishing · Paralithodes brevipes Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 312. Online publication date: April 24, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

2,3'-Dihydroxycanthaxanthin, a New Carotenoid with a 2-Hydroxy-4-oxo-.BETA.-end Group from the Hermit Crab, Paralithodes brevipes

A new carotenoid with a 2-hydroxy-4-oxo-beta-end group was isolated from the hermit crab, Paralithodes brevipes, as a minor component. Its structure was determined to be 2,3'-dihydroxy-beta,beta-carotene-4,4'-dione (1) by spectral data and the compound was named 2,3'-dihydroxycanthaxanthin. Chiral resolution of 1 by HPLC using a chiral column provided two stereoisomers, 1a and 1b. The 3'R and 3'S chirality were determined for 1a and 1b, respectively, by CD spectra.

Negative Effects of Delayed Mating on the Reproductive Success of Female Spiny King Crab, Paralithodes Brevipes

We investigated the effects of delayed mating on the reproductive success of female spiny king crabs, Paralithodes brevipes, in laboratory experiments where the duration between female molting and mating was controlled. Females mated and spawned irrespective of the number of days after their molting within 20 days. However, as the number of days after female molting increased, the fertilization rate decreased significantly. Females that spawned at 16 or more days after molting lost significantly more eggs than females that spawned at |$ \le 12$| days after molting. The percentage of detached eggs that developed normally to the morula stage decreased significantly in females mated at 20 days after their molting. The percentage of females with a few or no eggs tended to increase as time elapsed between molting and mating increased. Thus, the increased number of days after female molting influenced the reproductive success of spiny king crab females, and females had an optimal duration to mate after their molt. Our results suggest that the present fisheries of this species, in which only larger males are harvested, may affect female reproductive success by decreasing the availability of male mates. An adequate management of this species needs to include these considerations.

Effects of male mating frequency and male size on ejaculate size and reproductive success of female spiny king crab Paralithodes brevipes

Potential sperm limitation in a fished population of the spiny king crab Paralithodes bre- vipes was investigated in controlled laboratory experimental and field studies. The laboratory exper- iments examined the effects of male size and mating frequency on their reproductive potential and the recovery rate of exhausted sperm. The spawning success and fertilization rate of females decreased as the male mating frequency increased. The effects of increased male mating frequency on the spawning success of females and fertilization rates differed between male size classes. Male size and mating frequency have great influences on sperm limitation. Males showed little capacity to regenerate sperm, increasing the likelihood of limited sperm supply to females in fished population with low numbers of males due to male-selective fishing regulations. The field studies examined the structure of a fished population of P. brevipes in Hamanaka, eastern Hokkaido, before and after a change in the fishery regulations that permitted smaller males to be harvested. The results showed that a change in the sex ratio occurred after the fishery regulations were introduced, skewing the population towards females. The results also showed a decrease in the mean male size in the fished population. The results also indicated that a significant percentage of males (42.2%) had depleted sperm reserves just after the reproductive season. Overall, the results indicate that sperm limitation could occur in this fished population of P. brevipes. These observations may warrant a review of the current fishing regulations, particularly the minimum legal size.

A new method to extract sperm from spermatophores of the male spiny king crab Paralithodes brevipes (Anomura: Lithodidae)

A new method to extract sperm from spermatophores of the male spiny king crab Paralithodes brevipes (Anomura: Lithodidae)

Effect of temperature on growth and maturity of the king crabs <i>Paralithodes brevipes</i> and <i>P. camtschaticus</i> in the laboratory

The effect of temperature on growth and maturity was studied for the king crabs Paralithodes brevipes (Pb) and P. camtschaticus (Pc) in the laboratory. Molting and growth were examined individually in cultured first instar juveniles of Pb and Pc and in 2 and 3 y-old Pb collected in the wild (wild Pb). Crabs were fed mussels daily. Two temperature regimes were used, ambient (AT: -1 to 17°C) and controlled (CT: +11 to 13°C). After 4 y, Pb had reached instars 17-19 (71mm carapace length [CL], 330g) at AT, and instars 22-23 (95mm CL, 770g) at CT. Pc had reached instars 18-19 (82mm CL, 380g) at AT, and instars 20-21 (109mm CL, 1050g) at CT. Female 4 y-old Pc cultured at CT spawned after mating with 4 y males. Female Pb cultured at CT were not mature at 4 y although 4 y males did mate with 6 y females (wild Pb cultured from 2 to 6 y at AT). Thus, the growth pattern was similar between Pb and Pc, but CT had different effects on the maturation schedules of the females of the two species. At AT, no crabs were mature at 4 y.

EFFECTS OF SEX RATIO ON EGG EXTRUSION FREQUENCY AND MATING BEHAVIOR OF THE SPINY KING CRAB PARALITHODES BREVIPES (DECAPODA: LITHODIDAE)

The effects of sex ratio on the spawning frequency of females and on male mating behavior were examined in the spiny king crab, Paralithodes brevipes. Two types of guarding behavior were categorized based on when the male began guarding the female, that is, pre- and post-molting types, when the male starts guarding the female either before or after her molt, respectively. Males reared under a female-biased sex ratio more often showed the post-molting type than did males reared under an even ratio. Guarding duration for the pre-molting type, from the start of guarding to female molting, was significantly longer when the sex ratio was even than when females were more numerous (female : male ratio = 5:1). While there was no significant difference in the molting frequency of females between the two sex ratios, frequencies of egg extrusion were significantly lower for the female-biased ratio than for the even sex ratio. These results suggest that the sex ratio affects the mating behavior of P. brevipes and might be an important factor to manage wild populations and to produce seed crabs effectively in nursery tanks.

Effects of Sex Ratio on Egg Extrusion Frequency and Mating Behavior of the Spiny King Crab Paralithodes Brevipes (Decapoda: Lithodidae)

Effects of Sex Ratio on Egg Extrusion Frequency and Mating Behavior of the Spiny King Crab Paralithodes Brevipes (Decapoda: Lithodidae)

Important crab resources inhabiting Hokkaido waters

In this paper the fishing grounds, fluctuations in catches, history of exploitation, classification, distribution, migration, life history and resource trends of the edible crabs of the waters around Hokkaido are discussed. The Hokkaido crab fisheries developed along with the canning industry and there is now an increasing demand for boiled crab. At first, the most popular species was the king crab, Paralithodes camtschatica, but as its numbers declined other species such as the horsehair crab, Erimacrus isenbeckii, the banasaki crab, Paralithodes brevipes, the snow crab, Chionoecetes opilio, and the red snow crab, Chionoecetes japonicus, became popular. This report is based on the results of the latest research into the ecology and resources of the Erimacrus isenbeckii and Paralithodes brevipes species, which are currently the focus of resource conservation in Hokkaido.

Carotenoids of crustacea. VI. The carotenoids of crab Paralithodes brevipes (Hanasakigani in Japanese).

The carotenoids in the carapace, flesh and gonad of Paralithodes brevipes were investigated from the stereochemical point of view. The absolute configuration of papilioerythrinone (=3-hydroxy-β, e-carotene-4, 3'-dione) isolated from the crab was determined to be (3S, 6'R)-configuration. In the carapace and flesh, three stereoisomers of astaxanthin (33-39%) and (3S, 3'S)-7, 8-didehydro-astaxanthin (27-32%) were identified as major components accompanied by (3S, 3'S)-7, 8, 7', 8'-tetradehydro-astaxanthin (6-7%), fritschiellaxanthin (4-10%) and papilioerythrinone (2-6%) etc., while in the gonad β, β-carotene (64%) was found to be dominant along with three stereo-isomers of astaxanthin (11%), echinenone (7%) and isocryptoxanthin (3%) etc. From the experimental results obtained, we proposed the plausible oxidative metabolic path-way of lutein A to papilioerythrinone via fritschiellaxanthin in P. brevipes.

Digestive proteinases in five species of Lithodidae (Crustacea, Decapoda)

1. 1. The characteristics of digestive proteolysis and digestive proteinases in the crabs Lithodes aequispinus, Paralithodes camtschaticus, Paralithodes brevipes, Paralithodes multispina and Neolithodes nipponensis were studied. 2. 2. For five species, optimum pH was 7–7.5, optimum temperature was around 50°C and optimum pH for trypsin was found around 7.8–8.2. Proteolytic activity is stable in the pH range 6–8 and effects of metallic ions are similar in the five species. 3. 3. Trypsin, collagenase and leucin aminopeptidase were identified in the digestive glands of five species, carboxypeptidase A was found only in the hepatopancreas of Lithodes aequispinus and Paralithodes camtschaticus. However, neither chymotrypsin nor carboxypeptidase B were found. In addition, after gel filtration, a proteolytic activity was observed at low molecular weight fractions for five species.

Papilioerythrinone: A new ketocarotenoid in integuments of orange pupae of a swallowtail, Papilio xuthus, and carapaces of a crab, Paralithodes brevipes (hanasakigani in Japanese).

A minor carotenoid in integuments of orange pupae of a swallowtail, Papilio xuthus, was found also in carapaces of a crab, Paralithodes brevipes (hanasakigani). This new carotenoid showed a visible absorption spectrum similar to that of papilioerythrin (=α-doradexanthin) and was named papilioerythrinone. Reduction of this compound with sodium borohydride occurred in 2 steps and gave products identical with the reduction products of papilioerythrin. Therefore, the structure 3-hydroxy-β,e-carotene-4,3′-dione (IV) is ascribed to papilioerythrinone.