Influence of cadmium accumulation and dietary status on fatty acid composition in two colour forms of shore crabs, Carcinus maenas

 The effects of cadmium exposure and dietary status on cadmium accumulation, fatty acid (FA) content and profiles were investigated in two colour forms of the shore crab Carcinus maenas. Groups of shore crabs were either starved or fed with blue mussels, Mytilus edulis, during a 40 d exposure period to 2 or 6 μM Cd²⁺ (as CdCl₂). Starved green individuals accumulated more cadmium in haemolymph and hepatopancreas than did red crabs and green crabs fed during the experiments. In the red colour form, no difference in cadmium accumulation was observed between starved and fed individuals. In both colour forms, hepatopancreas contained more FA than gills and muscle. The FAs often present in the largest amounts in the tissues were 16:0, 16:1ω7, 18:1ω7, 18:1ω9, 20:4ω6, 20:5ω3 and 22:6ω3. However, saturated (SAFA) and mono-unsaturated fatty acids (MUFAs) were dominant in hepatopancreas, whereas poly-unsaturated fatty acids (PUFAs) were dominant in gills and muscles. At the beginning of the experiment, the total FA content in the hepatopancreas was 111.6 mg g⁻¹ (dry weight) for red crabs and 78.4 mg g⁻¹ for green shore crabs. During the experiment, however, the FA content decreased in red crabs. This decrease was more pronounced for starved individuals than for fed individuals. Also, the decrease in FA content was more pronounced in crabs exposed to 6 μM cadmium compared to crabs exposed to 2 μM or crabs not exposed to cadmium. No change in FA content was observed in green shore crabs, irrespective of diet and cadmium exposure. For both colour forms, no change in FA content was observed for gills and muscle. In red crabs, a decrease was observed for all FAs in the hepatopancreas. This decrease, however, was more pronounced for SAFAs and MUFAs than for PUFAs, indicating that the metabolism of FAs during starvation and cadmium exposure is selective. The experiments indicate that green colour forms of shore crabs are more tolerant of natural stress such as starvation and anthropogenic stress, e.g. cadmium exposure, than are red colour forms of shore crabs. Received: 23 September 1999 / Accepted: 29 April 2000     

Copper and zinc handling during the moult cycle of male and female shore crabs Carcinus maenas

Tissue concentrations and contents of copper and zinc were determined at 11 different stages of the moult cycle in male and female shore crabs Carcinus maenas. Metal concentrations in haemolymph, gills, midgut gland, muscle, and exoskeleton of males and haemolymph, gills, and midgut gland of females were determined, as were haemocyanin concentrations and haemolymph volumes (using ¹⁴C-inulin) in males. The changes in tissue Cu and Zn concentrations and contents that occur throughout the moult cycle can be attributed to muscle breakdown in late premoult, the period of starvation in late premoult and early postmoult, the resorption from and shedding of the old exoskeleton, and the dilution of the haemolymph caused by water uptake around the time of ecdysis. The present study demonstrates that whole-body Cu and Zn contents remain constant during a large part of the moult cycle of male and female C. maenas. This state of whole-body trace metal homeostasis is maintained in spite of major changes in tissue proportions and tissue Cu and Zn concentrations and contents. Previous studies have not carried out the necessary analysis to move from theoretical estimates to quantitative determination of the changes in tissue metal distribution associated with moulting in crustaceans; the data presented illustrate the necessity of measuring both tissue concentrations and contents of metals to avoid misinterpretation of either.     

Mechanisms of copper toxicity in the shore crab,Carcinus maenas

The influence of copper(II)chloride on selected key enzymes and metabolites in intermediary metabolism and the energy charge potential of the hyperregulating shore crab, Carcinus maenas (L.) were investigated. Crabs, collected in Odense Fjord, Denmark between September 1989 and May 1990, were exposed to 10 ppm copper(II)chloride, in 10 ppt salinity seawater at 15°C for up to 1 wk. Hexokinase activity was 77% lower in the posterior gills and 60% lower in the midgut gland than in control crabs. Phosphofructokinase activity was reduced in the midgut gland by 82% but was unaffected in the gills. Pyruvate kinase activity was undetectable in the gills of exposed crabs and reduced by 47% in the midgut gland. Citrate synthase activity was depressed by 30% in the posterior gills and unaffected in other tissues. Copper exposure had no apparent effect on tissue cytochrome c oxidase activity. Chela muscle was the only tissue in which copper exposure did not bring about reductions in the enzyme activities tested. As a result of 1 wk of copper exposure the average lactate level increased by 3.5-fold in haemolymph, 9.3-fold in posterior gills and 6.5-fold in midgut gland. The average glucose level was raised by a factor of 6 in the haemolymph, 3.4 in the posterior gills and 1.2 in the midgut gland. Energy charge potential was at a very high level (ca. 0.9) and was unaffected by copper exposure.     

Feeding,starvation and metabolic rate in the shore crab Carcinus maenas

The relationship between food intake and metabolic rate (as measured by oxygen consumption) of Carcinus maenas (L.) was studied. The metabolic rate of feeding crabs which had been starved for a short period increased, and several days were required for it to return to its original level. During prolonged starvation, the metabolic rate of C. maenas fell in two stages. The first reduction was to about 60% of the feeding level; this occurred during the first week of starvation. There was then a further reduction to about 40% of the feeding level and, at this level of metabolism, the crabs were able to survive for 3 months, with only 50% mortality; most of this occurred in the last 2 weeks. Metabolic rate was found to affect food intake; crabs acclimated to 24°C took 2.4 times as much food as crabs acclimated to 10°C, although the metabolic levels of the two groups differed by a factor of only 1.4. From the results obtained when the crabs were starved and when starved crabs were fed, it is suggested that, during starvation, the metabolic rate of C. maenas first drops from the elevated feeding level to a level at which carbohydrate reserves are utilised, and subsequently to a minimum level at which lipid reserves and proteins are used.     

Phenotype-environment matching in the shore crab (Carcinus maenas)

The shore crab (Carcinus maenas) exhibits a range of carapace pattern polymorphisms, but little is known regarding their function or maintenance. If patterns represent some form of crypsis, then associations between carapace colouration and substrate are expected; to determine whether such relationships exist, frequency of crab morphs and quantity of substrate type were measured from fifteen 10×40 m² quadrats at each of three sites along the southern shore of the Firth of Forth, Scotland. Five thousand one hundred and thirty-seven crabs and 3.6 km of line intercept transect data were collected during a 9-week period. Crab abundance, relative frequency of morphs and substrate type varied significantly among the three sites. Plain crabs were strongly associated with macro-algal substrates whereas patterned crabs were associated with mussel beds. This pronounced phenotype-environment matching, as well as various characteristics of the carapace patterns themselves, suggests that patterned crabs are cryptic on polychromatic backgrounds. The frequency of patterned crabs and the percentage of white pigment on the carapace both declined significantly with carapace width. The loss of pattern coincides with an ontogenetic shift in habitat use and we present evidence to suggest that individual crabs lose their pigment, rather than larger patterned crabs being preferentially removed from the population by predators. Throughout their life history, shore crabs encounter high variation in predation, food supply, and physical habitat; to survive they have evolved a strategy that includes elements of pattern polymorphism, crypsis, ontogenetic shifts, and plastic responses.     

Weapon size versus body size as a predictor of winning in fights between shore crabs, Carcinus maenas (L.)

Relative body size (carapace width) and weapon size (chela length) were used as indicators of resource holding potential (RHP) in the agonistic behaviour of male shore crabs, Carcinus maenas (L.). Weapon size was found to be a more reliable predictor of the outcome of pairwise fights than body size. Crabs with longer chelae than their opponents were more likely to win fights than crabs with relatively larger bodies. Body size had less influence on the outcome of fights. Relative body and weapon size did not influence initiation of contests but did affect the likelihood of winning; however, this was significant only for weapon size. Winning crabs had heavier claws with greater surface area than losing crabs. There was no relationship between relative size and fight duration. The frequency of cheliped display increased with chela length and win- ners performed significantly more displays than losers. Received: 5 February 1997 / Accepted after revision: 20 May 1997     

Conductive sodium entry in gill cells of the shore crab,Carcinus maenas

Isolated posterior gills of shore crabs, Carcinus maenas, collected from the Baltic Sea, were perfused and bathed with sea water and solutions of alkali chlorides. The preparation was used to measure fluxes of sodium from the external medium across the gills into the hemolymph and to determine transepithelial potential differences (PDs). Internally negative active transport PDs resulted from perfusion and bathing the gills symmetrically with the same medium (50% sea water). Passive (asymmetry) PDs following employment of 100% sea water as internal and 50% sea water as external medium were — in contrast to symmetry PDs — insensitive to cyanide and ouabain. This result indicates that the gill recognized the desired hyperosmotic state and responded by switching off the active transport component observed under symmetry conditions. Diffusional potential differences and fluxes of Na⁺ were inhibited by the externally applied diuretic amiloride. Gradients of pure alkali chlorides between medium and blood were accompanied by cation specific PDs. These PDs and their amiloride sensitivity were inversely related to the diameter of the unhydrated cation and allowed the calculation of the permeability sequence P: Li⁺>Na⁺>K⁺>Rb⁺>Cs⁺>Cl^-. The results obtained show that the permeability of the gills to cations greatly exceeds that to anions. In addition, these findings indicate that the initial amiloride-sensitive step in Na⁺ transport across the gill is not represented by an electroneutral sodium/proton exchange but by a conductive mechanism.     

Claw allometry in green crabs, Carcinus maenas: heterochely, handedness, and sex

Claw loss and reversal of handedness during regeneration are common phenomena in heterochelous decapod crustaceans, which typically have one large ‘crusher’ claw on the right side and a smaller ‘cutter’ claw on the left. Little is known about the relative importance of claw growth vs. body growth during claw regeneration. Here the relationship between claw size and body size of green crabs, Carcinus maenas, was examined to test for differences in claw allometry as a function of handedness and sex, as there are differences in how males and females use their claws. A total of 730 crabs (range = 15.7–83.6 mm CW) were collected from Maine to New Jersey, USA from May to October 1997, 2000, and 2004–2005. Claw growth, particularly crushers, was accelerated in left-handed crabs and in males compared to right-handed crabs and females respectively. These differing growth strategies highlight the role of sexual dimorphism in claw usage and the importance of achieving heterochely after claw injury. These results imply that handedness should be an important factor to consider in future studies of crab morphology, behavior, and morphometrics. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evaluation of changes in the adaptive physiology of shore crabs (Carcinus maenas) as an indicator of pollution in estuarine environments

The major objective of this study was to determine whether there were significant differences in the physiological responses of shore crabs (Carcinus maenas L.) sampled from environments with varying degrees of contamination. Crabs collected from a range of sites were subjected to a standardised, environmentally realistic sequence of physiological challenges in the laboratory to determine if such measures would prove sensitive enough to differentiate among the sites. Heart-rate changes and osmoregulatory ability were measured. The results indicated that changes in osmoregulatory ability were sufficiently sensitive to detect differences in environmental contamination. The utility of physiological measurements in environmental monitoring is discussed. Received: 2 July 1997 / Accepted: 10 July 1997     

Effect of copper on ion- and osmoregulation in the shore crab Carcinus maenas

The uptake and effect of dissolved copper on regulation of hemolymph osmolality and Na⁺, K⁺, Cl^-, Ca⁺⁺, and Mg⁺⁺ concentrations in the shore crab Carcinus maenas (L.) were determined at 400 mOsm (=14 S) ambient salinity. One mg Cu l^-1 resulted in 50% mortality in 11 to 22 d; the highest sensitivity was observed around the moulting period. 0.25 and 0.5 mg Cu l^-1 were not lethal after a onemonth exposure. Ten, 1, and 0.5 mg Cu l^-1 altered regulation of osmolality, Na⁺, K⁺, and Cl^- concentrations, while 0.25 mg Cu l^-1 did not. Exposure to 1 mg Cu l^-1 reduced hemolymph osmolality and Na⁺, K⁺, and Cl^- concentrations to 80 to 90% of controls within 4 to 6 d and no further reduction was observed during a 21-d exposure. The effect of various copper concentrations on these four parameters were almost identical and the highest sensitivity was observed around the moulting period. Hemolymph calcium levels increased 20 to 80% in crabs exposed to 1 mg Cu l^-1, while they decreased 20 to 30% in crabs exposed to 0.5 mg Cu l^-1. Prolonged exposure to copper caused 20 to 70% reductions in hemolymph magnesium levels. Crabs exposed to 0.5 mg Cu l^-1 for 29 d accumulated copper in hepatopancreas, gills, carapace, heart, testes, and hypodermis, but not in muscles and hemolymph. Increased copper levels in crabs exposed to 0.25 mg Cu l^-1 were observed in hepatopancreas, gills, and carapace only. The present results suggest that effects of copper on ion regulatory processes in part explain why the toxicity of copper towards euryhaline invertebrates increases at low salinities.     

Effect of salinity on hypoxia tolerance of resting green crabs, Carcinus maenas, after feeding

Mechanisms that can influence the tolerance of hypoxia in brackish waters were studied in resting and fed crabs, Carcinus maenas, at 15?°C. Mortality, blood oxygenation, acid-base status and lactate concentration were analysed in fed crabs held in full-strength normoxic seawater (32.5‰?S) and then transferred for 24?h to a partial pressure of oxygen (P_o2) of 3?kPa (1.4?mg?l^?1) and various salinities (17, 12.5, 10, 8‰?S). At salinity levels >10‰, fed crabs tolerated P_o2 values as low as 3?kPa in the ambient water and 0.5?kPa in their arterial blood for 24?h without switching to anaerobic metabolism. Only below 10‰?S did their blood-lactate content rise, leading to their death despite the fact that their blood O₂-content was twice the control value measured in full-strength normoxic seawater and their blood P_o2 did not decrease below values recorded at higher salinity levels. Addition of CO₂ to 8‰?S water (CO₂ partial pressure increasing from 0.1 to 0.3?kPa) decreased blood-lactate production and mortality, suggesting that at 10‰?S impairment of the O₂ supply is limited by an excessive blood O₂-affinity. The results are discussed in terms of the distribution (?10‰?S) of C. maenas along salinity gradients in estuaries and bays.     

Sodium regulation in the shore crab Carcinus maenas as related to ambient salinity

The activity of Na–K-ATPase was measured in crude homogenates prepared from various organs (leg muscle, pincer muscle, heart, testes, digestive gland, hypodermis, gills 1–9) of shore crabs, Carcinus maenas L., acclimated to salinities ranging between 10 and 50 S (in steps of 10 S). In all salinities tested, Na–K-ATPase activity was highest in posterior gills 7–9 (10–12 mol P_i mg protein^-1 h^-1), followed by anterior gills 1–6 (ca. 2.5 mol P_i mg protein^-1 h^-1) and the other organs (in most cases far below 2mol P_i mg protein^-1 h^-1). In gills only, Na–K-ATPase activity was salinity-dependent, with the highest values in the lowest salinities and vice versa. In gills 7–9, Na–K-ATPase activity was increased more than threefold following a reduction in salinity from 50 to 10 S. Na–K-ATPase activity, expressed as percentage of total ATPase activity, amounted to 60–80% in gills, about 60% in hypodermis and 20–40% in the other organs. Ouabain, a specific inhibitor of Na–K-ATPase activity, reduced serum osmolalities in crabs kept at 9–10 S only when injected into the hemolymph (1 and 5 · 10^-5 M), but had no effect when dissolved in ambient water (10^-4 M). The results obtained underline that crustacean gills are the main organs for ionic regulation, and confirm the hypothesis of the central role of the Na–K-ATPase in active Na uptake as the basic mechanism of hyperregulation in dilute media. Reduction of serum osmolalities following injection of ouabain into the hemolymph confirms previous reports on localization of the sodium pump in the basolateral parts of epithelial cells.     

Endogenous control of timing of metamorphosis in megalopae of the shore crab Carcinus maenas

Batches of hundreds of freshly collected megalopae of the shore crab Carcinus maenas (L.) showed persistent circatidal rhythms of moulting to the juvenile crab stage when maintained in constant laboratory conditions. Peaks of moulting occurred around expected times of high tides, with few megalopae moulting at other times. In larvae collected offshore, the highest tidally-timed peak of metamorphosis occurred during the second to fifth expected times of high tide, and metamorphosis of 50% of each batch took about 22 h or longer. In contrast, in larvae collected at the water's edge, 70% metamorphosed during the first expected episode of high tide, within 6 to 8 h after collection. However, although inshore megalopae moulted before offshore ones, the tidal timing of moulting remained unaltered whether megalopae were collected at neaps or springs, from the water's edge or farther offshore, in the presence or absence of natural substratum, and under various light–dark and salinity regimes. Metamorphosis of C. maenas megalopae around the times of high tides may enhance settlement into the upper intertidal zone. Early juveniles of the crab apparently prefer that zone as they are most abundant there and, unlike adults, do not undertake up-and-down-shore migration with tides. The present finding demonstrates, for the first time, endogenous physiological timing of circatidal periodicity in the metamorphic moult of crab megalopae, suggesting that endogenous factors, as well as exogenous ones should be taken into account in considering the process of settlement by crab megalopae. Received: 21 February 1996 / Accepted: 27 November 1996     

Occurrence and distribution of antioxidant enzymes in the haemolymph of the shore crab Carcinus maenas

The haemocytes and cell-free haemolymph of the shore crab Carcinus maenas were examined for the presence of the antioxidant enzymes, catalase (EC 1.11.1.6), glutathione peroxidase (GPX) (EC 1.11.1.9) and superoxide dismutase (SOD) (EC 1.15.1.1) by biochemical assay and immunocytochemistry. The results show that all three enzymes are present in the haemocytes, but vary in distribution and amount. Catalase was detected principally in the phagocytic hyaline cells, whereas GPX and SOD were found in both the hyaline and granular cells. Catalase and glutathione peroxidase activities were absent from the semi-granular cells, and although SOD was detected in some samples, there was enormous variation in the level of this enzyme between individuals. Cell-free haemolymph, by contrast, was found to be positive for GPX and SOD but lacked catalase activity. Immunocytochemical analyses further showed that only 2 to 16% of the cells stain positively for these enzymes, and where present the enzymes tended to be distributed throughout the cytoplasm. With the granular cells, however, there was some localization of GPX and SOD around the granules. Since the phagocytes of C. maenas are known to produce superoxide anion radicals, hydrogen peroxide, and possible other reactive oxygen species upon stimulation with phorbol myristate acetate, lipopolysaccharide, or concanavalin A in vitro, it is likely that catalase, GPX and SOD are present in the haemolymph to assist in protection of the host tissues against oxyradical damage during host defence in vivo.     

Voltage-clamp measurements on single split lamellae of posterior gills of the shore crab Carcinus maenas

Single split lamella preparations of posterior gills of low-salt adapted shore crabs Carcinus maenas (collected from the Kiel Bay, Baltic Sea in 1991) were mounted in a micro Ussing-chamber. With NaCl salines on both sides we found an outside positive potential difference (PD) of 6.6±1.3 mV, a short-circuit current (I_sc) of-240±65 Acm^-2 and a resistance (R_t) of 25±3 cm² (n=8). Substitution of Cl^- (gluconate) on both sides of the preparation resulted in a decrease of I_sc by more than 90% at constant R_t. I_sc disappeared and R_t increased after substitution of Na⁺ (choline). When ouabain (2 mmol l^-1) was applied to the internal NaCl-saline, I_sc decreased and R_t remained unchanged. Internal addition of 0.1 mmol l^-1 acetazolamide left I_sc and R_t unaffected. Application of amiloride to the external NaCl saline resulted in a increase of both inward negative I_sc and R_t. The dose dependence of the diuretic showed a maximal effect between 50 and 200 mol l^-1 with a half-maximal blocker concentration (K_AMI) of ca. 10 mol l^-1. The results show that the split lamella preparation of posterior gills of C. maenas is a low resistance epithelium which is able to effect a massive, electrogenic and coupled absorption of Na⁺ and Cl^-.     

Variations of hemolymph proteins of the common shore crab Carcinus maenas after a bacterial infection

The influence of a bacterial infection in Carcinus maenas both generally and with specific respect to hemolymph proteins is described. The infection shows severe effects upon the moulting cycle and general activity. The total protein concentration remains constant. Qualitative and quantitative differences between healthy and infected crabs appear, however, after electrophoretical separation (Disc-PAGE), indicating the importance of this method as an analytical tool in animal disease research. The protein pattern of the diseased crabs shows two new protein components. The origin of these additional fractions is discussed. Moreover, the levels of most other proteins, which are identified as hemocyanin subunits and a nonrespiratory protein, are higher in diseased crabs, thus indicating an elevated metabolic rate.     

Na-K-ATPase generates an active transport potential in the gills of the hyperregulating shore crab Carcinus maenas

Perfusing and bathing isolated gills of shore crabs Carcinus maenas with artificial saline or sea (brackish) water enabled us to determine potential differences (PDs) between ambient bathing medium and perfusion solution. Establishment of diffusional PDs was avoided by employment of the same solution on the internal and external side. The PDs measured were therefore of an active nature. We compared the properties of the PDs with the well-known properties of the Na-K-ATPase: dependence on biological energy (ATP), on salinity and sodium concentration, susceptibility of PD to depletion of internal K and to the addition of 5 mM internal ouabain. Considering also the magnitude of the PDs measured, the results obtained indicate that it is the Na-K-ATPase that generates an active transport potential for Na in the gills of shore crabs. This PD represents the driving force for the active uptake of Na in crabs that hyperregulate their body fluids when they inhabit environments of reduced salinity regimes or fluctuating salinities in tidal estuaries. This process counteracts diffusional losses of Na in crabs exposed to dilute media.     

Arsenic accumulation in the shore crab Carcinus maenas: the influence of nutritional state,sex and exposure concentration

The accumulation of arsenate from seawater by the shore crab Carcinus maenas L. (collected from Odense Fjord, Denmark in 1991 and from Restronguet Creek, UK in 1991) was investigated in a series of laboratory experiments. A field study was also carried out to determine the effects of raised environmental arsenic concentrations on intra-organismal distribution and tissue concentrations. Studies on the influence of nutritional state and sex on accumulation of As(5) from seawater indicated that most of the arsenic taken up from seawater in laboratory experiments was retained in the gills and the midgut gland. Arsenic accumulation exhibited sex-dependent differences which were also evident in correlation analyses carried out between total lipid contents and total arsenic contents of midgut glands of individual crabs. Arsenic concentrations in the gonads of both sexes were strongly influenced by the nutritional state of the crabs. Elevated arsenic concentrations in seawater and food at an arsenic polluted site (Restronguet Creek) significantly influenced arsenic concentrations and distribution among the tissues of C. maenas. Arsenic concentrations and distribution patterns differed markedly from those crabs from an unpolluted site in Odense Fjord. The gills of the crabs from Restronguet Creek contained extremely high arsenic concentrations ranging from 179 to 483 g As g^-1 dry wt. These values were even higher than those measured in the gills of Odense crabs that had been exposed to 3 mgl^-1 As(5) for 2 wk in the laboratory. Arsenic concentrations in the exoskeleton of Odense Fjord crabs were 15 times lower than those measured in exoskeletons of Restronguet Creek crabs. Approximately 69% of the total body burden of arsenic was located in muscle tissue of crabs from Odense Fjord, whereas the major pool of arsenic (46%) in Restronguet Creek crabs was located in the exoskeleton.     

A bacterial infection in the common shore crab Carcinus maenas and the fiddler crab Uca pugilator

A bacterial infection in Carcinus maenas and in Uca pugilator is described. The percentage of infections recorded in the field was between 0 and 10%, depending on season. Infected crabs remain about 3 times longer in Intermolt Stages C3 and C4 than do healthy crabs. In infected specimens of both species, the glucose level in the hemolymph is increased and protein, copper and lipid concentrations in the hemolymph as well as the glycogen content of various tissues are diminished. The coagulation process is disturbed in infected crabs. The hemocytes aggregate, but the formation of fibrin-like fibers, which can be observed in healthy crabs, does not occur.This paper forms part of a doctoral thesis presented at the University of Ulm (FRG).     

Cadmium accumulation in the female shore crab Carcinus maenas during the moult cycle and ovarian maturation

 The influence of moulting and ovarian maturation on cadmium accumulation in the tissues of female shore crabs Carcinus maenas exposed to 1 mg Cd l⁻¹ in the water was investigated. Cadmium accumulation in all tissues examined was markedly increased in crabs in the postmoult stages (A and B) compared to crabs in all other moult stages. During the moult cycle, average cadmium accumulation in the midgut gland ranged from 29 μg Cd g⁻¹ dw at premoult stage (D₂) to 589 μg Cd g⁻¹ dw at postmoult stage (A). Average cadmium concentrations in the haemolymph ranged from 0.56 μg Cd ml⁻¹ at intermoult stage (C₄) to 4.6 μg Cd ml⁻¹ at postmoult stage (A), while the gills accumulated from 103 μg Cd g⁻¹ dw in intermoult stage (C₃) to 352 μg Cd g⁻¹ dw in postmoult stage (A). Cadmium concentration in gills and haemolymph was also significantly higher in crabs in late premoult stage (D₃) compared to C₄-crabs, while midgut gland cadmium concentration remained elevated in C₁- and C₃- intermoult stages relative to C₄. During ovarian maturation the cadmium accumulation in midgut gland, gills, ovaries and haemolymph decreased. Average cadmium concentration in the midgut gland decreased from 63 μg g⁻¹ dw in ovarian Stage I to 19 μg g⁻¹ dw in ovarian Stage VI. The same pattern was observed for gills, haemolymph and ovaries. The present study demonstrates that cadmium accumulation in the female shore crab strongly depends on the physiological status of the animal. A possible association between physiological calcium requirements and cadmium accumulation during moulting is discussed. Received: 20 January 2000 / Accepted: 20 July 2000