Cancer Pagurus Research Articles

Levels of Cadmium in White and Brown Meat of Warty Crab (Eriphia verrucosa)

European Union regulations that establish the maximum cadmium (Cd) levels for crab take into account only concentrations found in crab muscle (white meat), mainly from appendages; therefore, other organs and tissues (brown meat) are excluded. The objective of the present study was to evaluate Cd levels in both white and brown crab meat, in order to achieve a more complete assessment of health risk related to human consumption of warty crab. Microwave digestion and atomic absorption spectrometry were used to determine Cd concentrations in warty crab (Eriphia verrucosa) samples collected from the southern Tyrrhenian Sea in Italy. Cd concentrations in all samples of white crab meat were found to be very low (below the limit of quantification), although brown crab meat showed significantly higher Cd concentrations (up to 5.629 mg/kg wet weight; mean value, 1.465 mg/kg). Thus, the consumption of brown meat, common among certain populations of the Mediterranean region, where whole crustaceans are traditionally eaten, substantially increased Cd intake, resulting in alarmingly high estimated weekly intake values.

1H NMR metabolomic profiling of the blue crab (Callinectes sapidus) from the Adriatic Sea (SE Italy): A comparison with warty crab (Eriphia verrucosa), and edible crab (Cancer pagurus)

The metabolomic profile of blue crab (Callinectes sapidus) captured in the Acquatina lagoon (SE Italy) was compared to an autochthonous (Eriphia verrucosa) and to a commercial crab species (Cancer pagurus). Both lipid and aqueous extracts of raw claw muscle were analyzed by 1H NMR spectroscopy and MVA (multivariate data analysis). Aqueous extracts were characterized by a higher inter-specific discriminating power compared to lipid fractions. Specifically, higher levels of glutamate, alanine and glycine characterized the aqueous extract of C. sapidus, while homarine, lactate, betaine and taurine characterized E. verrucosa and C. pagurus. On the other hand, only the signals of monounsaturated fatty acids distinguished the lipid profiles of the three crab species. These results support the commercial exploitation and the integration of the blue crab in human diet of European countries as an healthy and valuable seafood.

Structure and Characterization of Eriphia verrucosa Hemocyanin.

Arthropod hemocyanins (Hcs) are a family of large extracellular oxygen-transporting proteins with high molecular mass and hexameric or multi-hexameric molecular assembly. This study reports for the first time the isolation and characterization of the structure of an arthropod hemocyanin from crab Eriphia verrucosa (EvH) living in the Black Sea. Its oligomeric quaternary structure is based on different arrangements of a basic 6 × 75 kDa hexameric unit, and four of them (EvH1, EvH2, EvH3, and EvH4) were identified using ion-exchange chromatography. Subunit 3 (EvH3) shows high similarity scores (75.0, 87.5, 91.7, and 75.0 %, respectively) by comparison of the N-terminal sequence of subunit 1 from Cancer pagurus of the North Sea (Cp1), subunits 3 and 6 of Cancer magister (Cm3 and Cm6), and subunit 2 of Carcinus aestuarii (CaSS2), respectively. Moreover, a partial cDNA sequence (1309 bp) of E. verrucosa hemocyanin encoding a protein of 435 amino acids was isolated. The deduced amino acid sequence shows a high degree of similarity with subunits 3, 4, 5, and 6 of C. magister (81-84 %). Most of the hemocyanins are glycosylated, and three putative O-linkage sites were identified in the partial amino acid sequence of EvH at positions 444-446, 478-480, and 547-549, respectively. The higher stability of native Hc in comparison to its subunit EvH4 as determined by circular dichroism (CD) could be explained with the formation of a stabilizing quaternary structure.

Effects of Experimental Infection of Juvenile Edible CrabsCancer paguruswith the Parasitic Dinoflagellate Hematodinium sp.

A significant pathogen of crustaceans is thought to be Hematodinium. Much is known about the ecology and the effects of this disease on the sustainability of crustacean populations, but significantly less is known about the mode of transmission and fate of infected animals. Attempts have been made to transmit the disease under aquarium conditions to several species of crabs. These studies have shown a great deal of variation in the resulting levels of mortality and the timescale of disease progression. To determine if Hematodinium infections are the significant drivers of mortality in juvenile edible crabs (Cancer pagurus), crabs were injected with either 1 × 105 trophonts from an infected animal or sterile saline. Crabs were bled every 4 wk to determine the progression of infection and its effect on the total number of circulatory hemocytes. Thirty-three percent of the Hematodinium-injected crabs became infected and mortality occurred between 93 and 378 days postchallenge. Infected crabs appeared to molt less frequently than their uninfected counterparts. Both Hematodinium-infected and uninfected crabs exhibited infections by a number of other disease-causing agents including mikrocytid parasites, the fungus, Ophiocordyceps, and unidentified bacteria. These latter agents appear to be the key drivers of the mortality observed in both the Hematodinium infected and uninfected crabs.

Investigating the feasibility of using growth increments for age determination of Norway lobster ( Nephrops norvegicus) and brown crab ( Cancer pagurus)

It has recently been confirmed that some species of decapod crustacean retain their gastric mill and calcified region of the eyestalks throughout their moults. It had previously been assumed that crustacea lost all growth structures that could potentially record age information, such as the bones and otoliths in fish, through moulting. In this study, a novel preparation method was used for observing growth increments within these calcified structures of Nephrops norvegicusand Cancer pagurus(Linnaeus, 1758). This method involved: boiling, drying, resin embedding, sectioning, and polishing the gastric mill and eyestalks. Clear and readable growth increments were observed in longitudinal sections of the mesocardiac ossicle of the gastric mill for N. norvegicus, and longitudinal sections of the zygocardiac ossicle of the gastric mill for C. pagurus. Growth increments were also observed in longitudinal sections of the calcified region of the eyestalk for N. norvegicus. Validation is needed to confirm the periodicity of these growth increments.

Investigation of potential artefactual changes in measurements of impedance changes during evoked activity: implications to electrical impedance tomography of brain function

Electrical impedance tomography (EIT) could provide images of fast neural activity in the adult human brain with a resolution of 1 ms and 1 mm by imaging impedance changes which occur as ion channels open during neuronal depolarization. The largest changes occur at dc and decrease rapidly over 100 Hz. Evoked potentials occur in this bandwidth and may cause artefactual apparent impedance changes if altered by the impedance measuring current. These were characterized during the compound action potential in the walking leg nerves of Cancer pagurus, placed on Ag/AgCl hook electrodes, to identify how to avoid artefactual changes during brain EIT. Artefact-free impedance changes (δZ) decreased with frequency from −0.045 ± 0.01% at 225 Hz to −0.02 ± 0.01% at 1025 Hz (mean ± 1 SD, n = 24 in 12 nerves) which matched changes predicted by a finite element model. Artefactual δZ reached c.300% and 50% of the genuine membrane impedance change at 225 Hz and 600 Hz respectively but decreased with frequency of the applied current and was negligible above 1 kHz. The proportional amplitude (δZ (%)) of the artefact did not vary significantly with the amplitude of injected current of 5–20 µA pp. but decreased significantly from −0.09 ± 0.024 to −0.03 ± 0.023% with phase of 0 to 45°. For fast neural EIT of evoked activity in the brain, artefacts may arise with applied current of >10 µA. Independence of δZ with respect to phase but not the amplitude of applied current controls for them; they can be minimized by randomizing the phase of the applied measuring current and excluded by recording at >1 kHz.

Adaptive considerations of temperature dependence of neuromuscular function in two species of summer- and winter-caught Crab (Carcinus maenas and Cancer pagurus).

The aim of this study was to determine seasonal differences in the temperature dependence of neuromuscular parameters of the dactylopodite walking leg closer muscle in two species of freshly caught summer and winter decapod crabs. The relatively stenothermal Cancer pagurus (Cp) and eurythermal Carcinus maenas (Cm) muscle resting potential (RP) hyperpolarised significantly with increasing experimental temperature. The muscle RP in Cm was seasonally dependent at acute temperatures above 20°C whereas in Cp no seasonal effect was observed. The latent period of the muscle excitatory junction potential (EJP) following tonic motor nerve stimulation was significantly longer in winter-caught crabs in both species, although the effect was significantly more marked in Cp than Cm. Summer-caught Cp had larger excitatory junction potentials (EJPs) than did winter-caught crabs, a seasonal effect not seen in Cm. In contrast, marked seasonal differences were found in the EJP decay time constant in Cm having significantly longer time constants in winter-caught crabs, where no seasonal difference was found in Cp. These results suggest that different seasonal effects of neuromuscular parameters between Cm and Cp may reflect different strategies of response to their different seasonal temperature environments.

How does the dinoflagellate parasite Hematodinium outsmart the immune system of its crustacean hosts?

Dinoflagellates of the genusHematodinium infect over 40 species of marine crustaceans. Since the initial description of this parasite in France in the 1930s [1], it appears to have spread globally, causing economic loss in some species, including Tanner crabs (Chionoecetes bairdi) in Alaska [2], blue crabs (Callinectes sapidus) in the United States [3], edible crabs (Cancer pagurus) and Norway lobsters (Nephrops norvegicus) in Europe [4–7], sand crabs (Portunus armatus) in Australia [8], and Chinese swimming crabs (Portunus trituberculatus) in northern China [9]. Because this disease is thought to be fatal, it may be of great significance to the sustainability of both captive shellfish fisheries and aquaculture [10,11]. For instance, the decline in blue crabs from the Atlantic to Gulf Coasts in the US appears to be linked to epizootic outbreaks of disease caused byHematodinium [12]. Similarly, the reduction in velvet swimmer crab (Necora puber) numbers in Brittany in the 1980s has been attributed to the high prevalence of such infections [13]. Finally, the recent reports ofHematodinium infections in crabs and shrimp raised under aquaculture conditions in China [9,14,15] highlight the danger to additional, cultured crustacean populations. The number and host range of species ofHematodinium is unclear. Chatton and Poisson [1] identified one species of this parasite that they termed H. perezi. Notably, this species of parasite was reported in two different species of crabs from several locations around the French coast. A second species,H. australis, was first described in sand crabs fromMoreton Bay in Australia [8]. Recent studies making use of the variability of the ITS1 rDNA region ofH. perezi suggest that there are three clades (genotypes), I–III, of this species (see [11] for further details). Pagenkopp Lohan et al. [16] concluded that blue crab populations collected from the Atlantic to the Gulf coasts of the US were all affected by one genotype, H. perezi (III), which implies a large geographic range. Importantly, other species of crabs collected from the same region were also infected by the same genotype of H. perezi [16]. In Europe, there may be two clades of Hematodinium infecting a range of crabs. H. perezi genotype I has been reported in Liocarcinus depurator [17] and Carcinus maenas. The second species ofHematodinium, currently unnamed (Hematodinium sp.) infects a wider range of crustaceans, including edible crabs (C. pagurus). Importantly, these observations imply that this parasite is a host generalist and may be able to “jump” from host species to species, thereby making it a significant threat to a wide variety of commercially important decapods.

Disease profiles of juvenile edible crabs (Cancer pagurus L.) differ at two geographically-close intertidal sites

The prevalence of disease in edible crabs (Cancer pagurus) was assessed at two sites in South West Wales; one estuarine (Pembroke Ferry) and another facing open water (Freshwater East). Diseases included pink crab disease caused by Hematodinium sp., an infection of the antennal gland caused by Paramikrocytos canceri and an idiopathic inflammatory condition of the connective tissue surrounding the anterior ganglionic masses. This latter condition was only found in crabs from Pembroke Ferry. There was a significantly higher prevalence of pink crab disease at Freshwater East than Pembroke Ferry, although both sites had similar levels of infection by P. canceri.

Expression of RXR, EcR, E75 and VtG mRNA levels in the hepatopancreas and ovary of the freshwater edible crab, Oziothelphusa senex senex (Fabricius, 1798) during different vitellogenic stages.

The objective of the present study was to investigate the expression profile of retinoid X receptor (RXR), ecdysone receptor (EcR) and ecdysone inducible gene (E75) in the hepatopancreas and ovary of Oziothelphusa senex senex during different vitellogenic stages. RXR, EcR and E75 complementary DNAs (cDNAs) were isolated from the ovaries, while vitellogenin (VtG) cDNA was isolated from the hepatopancreas of vitellogenic female crab. Deduced amino acid sequence of the messenger RNAs (mRNAs) of RXR, EcR and E75 showed more than 80% identity with their respective mRNAs of other brachyurans. VtG mRNA was not detected in the ovary throughout vitellogenic stages. RXR and EcR were significantly increased in the ovaries during vitellogenic stage I. The levels of EcR, E75 and VtG in the hepatopancreas elevated significantly during vitellogenic stages I and II, whereas the levels of RXR elevated only in vitellogenic stage I. During vitellogenic stage III, the levels of RXR, EcR and VtG in the hepatopancreas were significantly decreased. Immunoprecipitation analysis revealed the presence of VtG in the haemolymph, hepatopancreas and ovary extracts from the females but absent in haemolymph and hepatopancreas extract of males. It can be inferred that RXR, EcR and E75 are involved in the regulation of synthesis of VtG in hepatopancreas, whereas in ovary, it is hypothesized that they play an important role in the uptake of VtG from the haemolymph, probably by regulating the levels of vitellogenin receptor. These are the first data showing an association between the expression levels of RXR, EcR and E75 and vitellogenesis and provide an alternative molecular intervention mechanism to the traditional eyestalk ablation to induce vitellogenesis and ovarian maturation in crustaceans.

Video capture of crustacean fisheries data as an alternative to on-board observers

AbstractFor EU member states to meet the requirements of the Marine Strategy Framework Directive and the reformed Common Fisheries Policy, it will be necessary to improve data collection related to many fisheries that are at present subject to relatively little monitoring or scientific research. This study evaluated the use of on-board camera systems to collect data from Cancer pagurus and Homarus gammarus fisheries. We evaluated the reliability of the hardware and its ability to collect images of sufficient accuracy and precision compared with using on-board observers. Fishers and on-board observers passed animals removed from traps across a defined area. The relationship between the in situ and predicted measurements of carapace length of lobsters or carapace width (CW) of crabs was investigated. The mean difference between the predicted and real crab measurements was −0.853 mm with a standard error of 0.378 mm. Suggesting that the model tends to underestimate the real CW slightly. The mean difference between predicted and real data for lobsters was 0.085 mm with a standard error of 0.208 mm. Sex allocation for crabs based on video images was 100% accurate. All male lobsters were correctly assigned. For lobsters >86 mm in length, the correct female sex allocation was 100% accurate. For smaller lobsters, the accuracy of sex allocation decreased to a low of 51% in lobsters <70 mm. Camera systems were found to be a suitable method for collecting data on the size and sex of crabs and lobsters. The error attributable to using video data rather than manual measurement was less than 3 mm, which is sufficient to detect growth increments in these species. The requirements to collect basic species data are increasing and the ability to do so without on-board observers will reduce the cost implications of these requirements. Future computer automation of image extraction and measurements will increase the application of video systems for data collection.

Small-Scale Nekton Density and Growth Patterns Across a Saltmarsh Landscape in Barataria Bay, Louisiana

Nekton on the northern Gulf of Mexico depend on estuarine nursery areas, but patterns of habitat use and the underlying processes that drive these patterns are not fully understood. We examined small-scale (1–50 m) patterns of habitat use in Barataria Bay by collecting nekton samples between 2002 and 2006 with a 1-m2 drop sampler. Habitat-specific densities were estimated for six habitat types at various distances from the shoreline in marsh (Marsh1M = 1 m and Marsh3M = 3 m) and over shallow nonvegetated bottom, SNB (SNB1M = 1 m, SNB5M = 5 m, SNB20M = 20 m, and SNB50M = 50 m). Habitat-specific growth rates also were estimated for brown shrimp Farfantepenaeus aztecus caged in SNB1M, SNB5M, and SNB20M. Nekton density patterns in Barataria Bay appeared to be clearly different from the Galveston Bay model, which predicts nekton distribution patterns relative to the marsh shoreline. Although densities in Barataria Bay were significantly higher in samples near the marsh shoreline (Marsh1M or SNB1M) for brown shrimp, blue crab, and white shrimp, highest mean densities were not always present in marsh edge vegetation. In addition, densities of brown shrimp and white shrimp in Barataria Bay declined much more steeply with distance into the marsh than in the model. Daily growth rates (1.0–1.2 mm TL day−1, 68–89 mg day−1) for brown shrimp were similar among SNB habitat types. Our results suggest that SNB in Barataria Bay may be relatively more important as habitat for fishery species than previously assumed.

Are European lobsters (Homarus gammarus) susceptible to infection by a temperate Hematodinium sp.?

Hematodinium spp. infect over 40 species of crustaceans worldwide, but have not been reported to infect the European lobster, Homarus gammarus. In this study, Hematodinium parasites (a mixture of uni- and multinucleate trophont-like stages) were taken from donor crabs (Cancer pagurus) and injected into juvenile H. gammarus. Juvenile C. pagurus were also injected with the same inoculum. Haemolymph was taken at regular intervals and examined for the presence of Hematodinium using light microscopy and PCR, in two separate experiments of duration 4 and 8months. All lobsters were negative for Hematodinium whilst the C. pagurus challenged became infected. It is concluded that European lobsters are not susceptible to infection with a clade of Hematodinium that infects C. pagurus.

Isolation & identification of bacteria for the treatment of brown crab (Cancer pagurus) waste to produce chitinous material.

To isolate bacteria from soil for microbial pretreatment of brown crab (Cancer pagurus) shell waste and the production of chitin. Isolates were screened for protease enzymes and acid production in order to facilitate the removal of protein and calcium carbonate fractions from brown crab shell to yield a chitinous material. Selected isolates were applied in various combinations in successive, two-step fermentations with brown crab shell waste. These isolates were identified as: Exiguobacterium spp. (GenBank accession number: KP050496), Bacillus cereus (GenBank accession number: KP050499), B.subtilis (GenBank accession number: KP050498), Bacillus licheniformis (GenBank accession number: KP050497), Pseudomonas migulae (GenBank accession number: KP050501), Pseudomonas spp. (GenBank accession number: KP050500), Pseudomonas spp. (GenBank accession number: KP050502), Arthrobacter luteolus (GenBank accession number: KP050503), Lactobacillus spp. (GenBank accession number: KP072000) and Enterococcus spp. (GenBank accession number: KP071999). Successive two-step fermentations with isolates in certain combinations resulted in a demineralization of >94% and the extraction of a crude chitin fraction from brown crab processing waste. The highest demineralization, 98·9% was achieved when isolates identified as B.cereus and Pseudomonas spp. were used in combination. The transfer of fermentations to a larger scale requires further research for optimization. The successful application of these isolates in successive two-step fermentation of brown crab shell waste to extract chitin means with further research into optimization and scale up, this chitin extraction process may be applied on an industrial scale and provide further commercial value from brown crab shell waste.

저장기간 및 저장온도에 따른 꽃게풍미 볶음밥의 품질변화

The edible crab is among the rich resources that can be used as materials for food products, but living crabs and crabs marinated in soy sauce are the only widely utilized materials for food products. For seafood development, research is needed to promote the use of crabs in various products. In this study, the quality changes of fried rice prepared with crab meat, crab emulsion sauce and crab cooker effluent were investigated. The pH and acidity values did not show any significant difference at –20°C. The acidity of the fried rice continuously increased during storage at 4 and 25°C. The VBN and TBA values of the fried rice stored at 4 and 25°C were significantly higher than those of the fried rice stored at –20°C during the storage period. The viable cell count of the fried rice stored at –20°C changed little during the storage period while that of the fried rice stored at 4 and 25°C rapidly increased over 2 weeks. For the fried rice stored at –20°C, the overall quality did not show significant differences during the storage period. In conclusion, the best storage temperature for both quality and safety was found to be –20°C. At such storage temperature, the quality of the stored instant rice using crab meat did not change, and through research the expanding possibilities of using crab materials were confirmed.

Nassariid whelks hitch-hiking on Cancer pagurus: phoresis, commensalism or fouling?

The behavioural responses of scavenging animals to mackerel (Scomber scombrus) baits were studied by short-term video photography in shallow water (16–18 m depth) at Lough Hyne, Ireland. Earliest arrivals (after seconds/minutes) at baits were small fish or swimming crabs (Liocarcinus depurator), followed by crawling portunid crabs. After tens of minutes, juvenile whelks 2–4 mm shell length (Nassarius reticulatusand/orNassarius incrassatus) sometimes arrived to feed. They moved at a mean speed of 1.24 (SD 0.392) mm s−1. After tens of minutes or hours, single large scavengers arrived, consuming most of the bait; the most common of these wereCancer pagurusthat fed in a wasteful fashion, generating large quantities of mackerel scraps.Cancer pagurusmoved into view at a mean speed of 48.7 (SD 16.9) mm s−1(39 times the whelk speed). A single individual ofC. pagurus(197 mm carapace width) arrived at a bait carrying 24 juvenile whelks on the dorsal surface of its carapace. No whelks were present on walking legs or chelipeds. The crab fed for 6.8 min and 3 whelks fell off before it departed. The nature of this crab/whelk association is discussed; on balance it appears that it is a previously unreported example of phoresy/phoresis. No whelks were observed being carried by other edible crabs or upon large numbers of scavenging portunid crabs.

13-Cis-Retinoic Acid-Induced Hyperglycemia in the Fresh Water Edible Crab, Oziothelphusa Senex Senex is mediated by Triggering Release of Hyperglycemic Hormone from Eyestalks

The present study was aimed to investigate the effect of 13-cis-retinoic acid (13-CRA) on hemolymph glucose levels in the fresh water edible crab, Oziothelphusa senex senex. Injection of 13-CRA significantly increased hemolymph glucose levels in a dose-dependent manner in intact crabs. Bilateral eyestalk ablation (ESX) resulted in significant decrease in hemolymph glucose levels. Injection of 13-CRA in to ESX crabs did not cause any significant changes in hemolymph glucose level as compared to ESX crabs suggesting that the effect of 13-CRA could be on the neuroendocrine system in the eyestalks increasing secretion of hyperglycemic hormone. To test this hypothesis, eyestalks were collected from control and 13-CRA injected crabs, and tested for hyperglycemic effect and also for the hyperglycemic hormone levels. The levels of hyperglycemic hormone and the hyperglycemic effect were significantly low in the eyestalks collected from 13-CRA injected crabs when compared with eyestalks from control crabs. From results, it is hypothesized that 13-CRA-induced hyperglycemia in the crab, O. senex, is mediated by triggering the release of hyperglycemic hormone from the eyestalk.

RETRACTED ARTICLE: Structure and characterization of cancer pagurus hemocyanin.

RETRACTED ARTICLE: Structure and characterization of cancer pagurus hemocyanin.

Characterization and anti-settlement aspects of surface micro-structures from Cancer pagurus

Tuning surface and material properties to inhibit or prevent settlement and attachment of microorganisms is of interest for applications such as antifouling technologies. Here, optimization of nano- and microscale structures on immersed surfaces can be utilized to improve cell removal while reducing adhesion strength and the likelihood of initial cellular attachment. Engineered surfaces capable of controlling cellular behaviour under natural conditions are challenging to design due to the diversity of attaching cell types in environments such as marine waters, where many variations in cell shape, size and adhesion strategy exist. Nevertheless, understanding interactions between a cell and a potential substrate for adhesion, including topographically driven settlement cues, offers a route to designing surfaces capable of controlling cell settlement. Biomimetic design of artificial surfaces, based upon microscale features from natural surfaces, can be utilized as model surfaces to understand cell–surface interactions. The microscale surface features of the carapace from the crustacean Cancer pagurus has been previously found to influence the rate of attachment of particular organisms when compared to smooth controls. However, the nature of microscale topographic features from C. pagurus have not been examined in sufficient detail to allow design of biomimetic surfaces. In this work, the spatial distribution, chemical composition, size and shape descriptors of microscale surface features from C. pagurus are characterized in detail for the first time. Additionally, the influence of topography from C. pagurus on the settlement of marine diatoms is examined under field conditions.

Parasitization of juvenile edible crabs (Cancer pagurus) by the dinoflagellate, Hematodinium sp.: pathobiology, seasonality and its potential effects on commercial fisheries.

This study reports on the prevalence and severity of infections caused by the parasitic dinoflagellate, Hematodinium in juvenile edible crabs (Cancer pagurus) found in 2 intertidal survey sites (Mumbles Head and Oxwich Bay) in the Bristol Channel, UK. Crabs were assessed for the presence and severity of Hematodinium infections by the histological examination of infected tissues. Such infections were found to exhibit a seasonal trend in the 2 study areas with high numbers of animals (ca. 30%) infected in the spring to summer but with low severity. Conversely, in November only ca. 10% of crabs were infected but these animals had large numbers of parasites in their haemolymph and other tissues. At this time, the carapace and underlying tissues of infected crabs had the chalky, pinkish-orange appearance that is characteristic of this disease. Hematodinium-infected crabs ranged in size from 12 to 74 mm carapace width. Overall, it is concluded that the high prevalence of infection of juvenile crabs in this area may have implications for the sustainability of the edible crab fishery in the Bristol Channel.