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Norway lobsters, Nephrops norvegicus, are sediment-dwelling decapod crustaceans that excavate burrows from which they make short excursions to feed by predation and scavenging. The females of this species are known to reside within their burrows for an extended period of time over the winter while brooding their eggs. The aim of this study was to assess the likelihood of these females being able to feed during this brooding period. Biophysical and biochemical measurements that had previously been shown to change with starvation under laboratory conditions in male N. norvegicus were taken for female N. norvegicus under similar conditions. These measurements were also compared in both sexes obtained from monthly trawl samples from the Clyde Sea Area, Scotland, UK, together with trawl composition data. The laboratory study showed that the hepatosomatic index, and the copper, lipid and water content of the hepatopancreas can be used as indicators of the state of starvation in females, as in males. In the wild, both sexes have reduced nutritional status during the winter, but not to the degree seen in animals starved for 20 weeks in aquarium trials. This study does not support the hypothesis that females cease feeding over winter, during their brooding period. Firstly, some females were unable to sustain ovary development during starvation under controlled conditions, contrary to field observations. Secondly, field data suggest that there is no sex-specific reduction in nutritional status.

The effects of capture method (creel and trawl) and trawling time (15, 60 and 150 min) were assessed in Norway lobsters by measuring stress-related metabolites together with nucleotide breakdown products. Furthermore, mechanical damage was scored in the animals captured by trawl. Capture method had a clear impact on the nucleotide profile in the Norway lobster muscle. In rested and creel-caught animals the main nucleotide was ATP, while in trawled animals the main nucleotide was AMP. According to these results the Adenylate Energy Charge (AEC) was lower in trawled animals compared with creel-caught animals, while trawling time did not affect AEC levels significantly. Stress-related and anaerobic metabolites together with muscle pH indicated that trawled animals, even at the shortest time tested, were using anaerobic metabolism. In the haemolymph, l-lactate increased with a delay compared with muscle, suggesting that the concentration of l-lactate in the muscle provides a more immediate measure of...

The post-mortem processes in the fast abdominal muscle of the Norway lobster Nephrops norvegicus have been investigated by simulating the first 24-h post-harvest in a controlled experiment. Tissue pH and the concentrations of arginine phosphate, glycogen, L-lactate, ATP, ADP, AMP, IMP, HxR, and Hx were measured at the time of sacrifice and 3, 6, 12 and 24 h thereafter. Additionally from the nucleotide values the corresponding adenylate energy charge (AEC) was calculated. The results reveal that the post-mortem biochemical processes in the abdomen of the Norway lobster after sacrifice and during storage at 10°C are comparable to those of vertebrates. It was found that arginine phosphate was depleted from 38.5 ± 5.2 to 10.9 ± 2.9 µmol g−1 within 3 h, and anaerobic glycolysis was enhanced, so that glycogen was depleted and L-lactate accumulated. The muscle pH decreased significantly from 7.6 ± 0.1 to 7.0 ± 0.15 within 20 min and then continued to decrease at a slower rate. Most interestingly, the ATP concent...

For economic and logistical reasons, an increased proportion of landings from trawl caught Nephrops norvegicus is being used in the live export trade. This paper reports a series of trials that investigate the impact of capture method and trawl duration on the levels of stress, damage and mortality of N. norvegicus. The stress of N. norvegicus captured during trials in spring and autumn by means of short trawl (1 h duration), long trawl (5 h duration) and creeling was assessed using a range of physiological measures (for haemolymph l -lactate, crustacean hyperglycaemic hormone (CHH) and abdominal muscle glycogen concentrations), the immunological status (total haemocyte counts (THC)) and physical assessments (mortality, damage indices). N. norvegicus caught by creeling were generally less stressed (i.e. significantly lower haemolymph l -lactate and CHH concentrations) than their trawled counterparts. Increased duration of trawl did not significantly alter physiological parameters, while time of landing did have a significant effect on l -lactate concentrations, as individuals landed in the morning exhibited higher concentrations. Irrespective of the season in which trawling occurred, individuals captured by short trawls in the morning suffered lowest mortalities. Damage assessment data revealed that a greater proportion of individuals was categorised as heavily damaged following longer trawls conducted in spring.

A multivariate approach has been used to study progression in the post-capture condition of trawl-caught Nephrops norvegicus destined for the live transport market. A range of biochemical (L-lactate, glucose, glycogen), endocrinological (crustacean hyperglycaemic hormone), immunological (total haemocyte counts, phenoloxidase), microbiological and pathological measures of condition were utilised. During prolonged periods of aerial exposure N. norvegicus experience large disruptions to the carbohydrate profile, with increases in haemolymph L-lactate and crustacean hyperglycaemic hormone concentrations, and corresponding fluctuations in haemolymph pH; the severity of this disruption increases with the temperature of aerial exposure. This in turn impacts on the immune competence of the lobsters, with significant reductions in the number of circulating haemocytes and phenoloxidase levels observed as well as increases in the degree of bacteraemia of the haemolymph. Utilising evidence obtained during histological and other studies, possible causes of the immuno-suppression and subsequent meat spoilage are discussed. The information obtained should help to identify critical periods in the post-capture period that promote poor stock condition and mortality. Such data may be used to generate an internationally accepted Code of Practice for the capture, handling and transport of commercially exploited decapod crustaceans.

The burrowing behaviour and burrows of the snapping shrimp Alpheus glaber are described from laboratory observations of animals collected by trawl at 72 m depth off Ancona, Central Adriatic. Resin casts of burrows were taken in laboratory aquaria. At depths of 35–78 m off Ancona, burrows consistent with those seen in aquaria were observed using underwater television. A single specimen of A. glaber was seen retreating into a burrow. A morphometric analysis demonstrated differences in relative growth between the sexes that may be related to reproductive biology of A. glaber. Analysis of stomach contents of several demersal fish and large decapod Crustacea provided evidence of the role of A. glaber in the food-web of the muddy trawling grounds exploited by the local fishing fleet.

Comparative studies of the haemocyanin of five species of thalassinidean mud-shrimps showed that all five species exhibited a high oxygen affinity (P50 range=1.0–9.3 Torr, at in vivo pH, 10°C). Each of the mud-shrimps exhibited a moderately large Bohr coefficient (−1.06 to −1.48) and values for the co-operativity of the haemocyanin did not differ greatly between the species (n50 range=2.3–3.8). The highest oxygen affinities were recorded for the haemocyanin of Callianassa subterranea, Jaxea nocturna and Calocaris macandreae, whereas those for the two species of Upogebia were slightly lower but were still higher than in many other decapods. The higher oxygen affinity of the haemocyanin of the deposit feeding shrimps C. subterranea, J. nocturna and C. macandreae compared with that of the haemocyanin of the filter feeding upogebiids may be correlated with the fact that conditions within the burrows of the deposit feeders may be more severely hypoxic. The oxygen affinity of all five species showed a moderate temperate sensitivity (ΔH −56.8 to −82.1 kJ mol−1 over temperature range 5–10°C). Studies of the haemocyanin of one species (C. macandreae) showed that L-lactate did not affect the oxygen affinity of the haemocyanin as has been reported for a number of other decapod species. The oxygen carrying capacity of the haemocyanin (CHCYO2) was similar in four of the species studied (0.22–0.42 mmol l−1) but that of C. subterranea was significantly greater (0.83 mmol l−1). The higher protein concentration of the haemolymph of this species also resulted in the haemolymph having a greater buffering capacity (−7.67 mmol l−1 pH unit−1). SDS–PAGE studies of the haemocyanin demonstrated the presence of 3 subunits in the upogebiids but additional subunits were observed in the other species (MW range=70 000–90 000 Da). Studies of the association state of the haemocyanin of three of the species showed that the haemocyanin of both C. macandreae and J. nocturna was present mainly in the form of eikositetramers (24-subunit aggregation state) with some hexameric haemocyanin also occurring. The haemocyanin of Upogebia deltaura, however, occurred as a mixture or eikositetramers and dodecamers.

Burrows inhabited by Upogebia deltaura (Crustacea: Thalassinidea) were studied over a two-year period on two maerl beds at 10 m below Chart Datum (CD) in the Clyde Sea area, Scotland. Labelled burrows proved to be stable features on each ground, with animals able to withstand the impacts of scallop dredging and storm disturbance by re-building the damaged upper sections of their burrows. Resin casts excavated using an air-lift showed that these burrows were inhabited by single individuals. Burrows were deeper, larger and more complicated than was previously thought typical for U. deltaura and other members of the genus. Mapping of burrow systems revealed average densities of 2.9 ind m−2 with up to ten openings m−2. These elusive animals were the deepest burrowing megafauna (to 68 cm) and the most abundant large crustaceans within the maerl bed habitat.

The addition of sulphide and thiosulphate (final concentration of 1 mmol l−1) to the haemolymph of the benthic decapod crustaceans Calocaris macandreae Bell, Nephrops norvegicus (L.) and Carcinus maenas (L.) had no effect on the ability of the haemocyanin to combine with oxygen in vitro. The addition of sulphite resulted in the deoxygenation of the haemocyanin but this could be reversed by exposure to air. There were pronounced differences between the species in both the oxygen affinity of the haemocyanin (P50 at pH 7.8, 10°C=1.4 Torr, 8.6 Torr and 21 Torr in C. macandreae, C. maenas and N. norvegicus, respectively) and in the magnitude of the Bohr coefficient (−1.12, −0.84 and −1.15 in C. macandreae, C. maenas and N. norvegicus, respectively). The addition of thiosulphate at concentrations between 0.5 and 1.5 mmol l−1 to the haemolymph of C. maenas and N. norvegicus had no effect on the oxygen affinity of the haemocyanin. This was also true for the haemolymph of C. macandreae except that at the highest concentration used (1.5 mmol l−1) there was a slight but significant reduction in the P50 value. The addition of thiosulphate to the haemolymph had no effect on the Bohr coefficient or on the cooperativity of the haemocyanin in these species. Even though C. macandreae may be exposed to sulphide in the burrows that it constructs in sublittoral mud sediments, it would appear unlikely that the thiosulphate that accumulates in the haemolymph resulting from the oxidation of sulphide entering the body has a significant effect on the respiratory properties of the haemocyanin.

The gut morphology is described for seven species of Thalassinidea; Callianassasubterranea (Montagu), Jaxea nocturna Nardo, Axius stirhynchus Leach, Calocaris macandreae Bell, Upogebia pusilla (Petagna), U. deltaura (Leach) and U. stellata (Montagu). Differences were observed in the structure of the dorsal and lateral teeth of the gastric mill. Callianassa subterranea and A. stirhynchus had simple robust dorsal teeth and proportionally larger lateral teeth with flexible spines. The three upogebiids had complex dorsal teeth that were highly ridged and proportionally smaller lateral teeth with inflexible spines. The dorsal and lateral teeth of J. nocturna were intermediate in form. The dorsal tooth of Calocaris macandreae, although relatively simple in design, possessed accessory projections, or “wings”, on either side of the main structure. The lateral teeth were proportionally quite large, but lacked ridges and spines. The epithelia surfaces of the digestive gland, midgut and posterior diverticulum were similar for all seven species. Differences were observed in the morphology of the hindgut. The hindgut lining was completely smooth for the three upogebiid species. The other thalassinidean species had four distinct rows of cuticular projections situated on top of the ridges formed by the longitudinal convolutions of the hindgut. The arrangement of these projections varied between species. A gut flora was observed for six of the seven species, the exception being C. macandreae. The differences observed in the structure of the gut are discussed in relation to feeding and thalassinidean phylogeny.

The monthly variations in the gut contents of Calocaris macandreae, principally a deposit feeder, and Upogebia stellata, principally a suspension feeder, were examined over the period of a year. The diet of both species consisted of a mixture of organic and fine inorganic fragments. The identifiable components of their respective diets included diatoms, dinoflagellates, algal and terrestrial plant fragments, and material of animal origin. The contribution of these different dietary components varied between the two species, and also over the year within each species. Using Strauss' Linear Food Selection Index (L) it was found that U. stellata positively selected diatoms, dinoflagellates and plant and algal fragments whilst avoiding animal material. In contrast, C. marandreae showed little evidence of food selectivity, except in the case of algal material which was positively selected. In general, variations observed in the diet were related to changes in food abundance and availability within the...

Changes in the biochemical composition of the ovary of Nephrops norvegicus (L.) were examined throughout maturation at stations with fast and slow growing individuals in Scottish waters and in the Mediterranean. Ovary index (ovary wt:total body wt) increased significantly with maturation. Lipid, protein and water content of the ovary increased with maturation, while carbohydrate content decreased. Similar changes were also identified in the hepatopancreas. Significant spatial differences in ovary and hepatopancreas composition were identified, which may be related to whole-body growth rate. The ovary maturation scale commonly used for N. norvegicus was shown to reflect biochemically distinct stages in ovary development.

Upogebia stellata and U. deltaura (Crustacea: Thalassinidea) construct burrows in nearshore sediments in U.K. waters. Burrow structure is similar in both species; the basic burrow consisting of a two-opening, U-shaped section with a vertical shaft descending from the mid-point of the U. This structure may be variously elaborated. Burrow cross-section is circular, dilations allow turning by somersaulting and surface openings are often constricted. Conditions within the burrows are usually hypoxic and hypercapnic. Burrow water PO 2 in the parts normally occupied by the mud-shrimp was between 80-110 Torr, but was much lower (10-45 Torr) in the deepest, poorly-irrigated parts. Both species irrigate their burrows by episodes of pleopod beating of variable duration (mean=8.5 ± 3.5 min and 2.8 ± 0.5 min for U. deltaura and U. stellata, respectively), which draws oxygenated water into the burrow and also particulate food for suspension feeding. When exposed to hypoxia, U. deltaura and U. stellata were able to maintain their rates of oxygen consumption approximately constant over a wide range of PO 2 (Pc=30-50 Torr). Under these conditions, there was a pronounced increase in scaphognathite beat rate but heart rate remained relatively constant. Below the Pc, however, both rates declined.

The effects of temperature on aspects of the respiratory physiology of two semi-terrestrial crabs, Uca inversa and Metopograpsus messor have been studied. When exposed to increasing temperatures in the laboratory both species show a pronounced increase in both the rate of oxygen consumption (Mo2) and in heart rate; Q10 values were approximately 2–3 over the temperature range 15–40°C for both Mo2 and heart rate. Temperature did not, however, affect the relationships between Mo2 and fresh body weight and between heart rate and fresh body weight. The haemocyanin of both species was found to have a high oxygen affinity (P50 = 6.4 and 12.4 Torr for U. inversa and M. messor, respectively, pH = 7.9, temperature = 30°C) and moderately high Bohr values (−1.07 and −0.96 for U. inversa and M. messor, respectively). An increase in temperature resulted in a significant decrease in the oxygen affinity of the haemocyanin of both species (ΔH = −51.7 and −57.4 kJ.mol−1 for U. inversa and M. messor, respectively). Changes in temperature did not have a significant effect on either the Bohr value or the cooperativity of the pigment.

Bopyrids are highly modified epicaridean isopod ectoparasites with the adult females showing extreme specialization of body form when compared with free-living isopods (Shiino, 1965). The smaller males are similar to free-living isopods, retaining the basic cryptoniscus larval form (Naylor, 1972), and are typically found in the brood chamber of the female or attached to the ventral surface of the female's pleon (Salazar-Vallejo & Leija-Tristán, 1989).Whilst examining the branchial morphology of the upogebiids,Upogebia stellata(Montagu),Upogebia deltaura(Leach) andUpogebia pusilla(Petagna) as part of a wider study of the physiological ecology of thalassinidean mud-shrimps, some shrimps were observed to have a branchial gall (distended branchiostegite) containing a bopyrid parasite. In this short note we add to the previous records of two bopyrid species and briefly discuss the host/parasite relationship.Parasitized material examined:U. stellata(three males, two females) collected subtidally using an anchor dredge from White Bay, Isle of Cumbrae, Scotland (55°48'N 4°55'W) at depths of 25–30 m. A single male specimen ofU. deltaurawas caught using a box corer from the Irish Sea (54°7'N 3°27'W).Upogebia pusilla(one male, one female) were collected intertidally from the Arcachon Basin, France (44°40'N l°10'W) by Professor J.P. Truchot. Prior to examination, the mud-shrimps were preserved in 10% buffered formalin, the parasites removed, rinsed with distilled water and transferred to 70% ethanol. Some preserved material was also available from the Robertson Collection housed at the University Marine Biological Station Millport.Parasitized mud-shrimps had an enlarged branchial chamber, or branchial gall, a result of branchiostegite deformation caused by the presence of the parasite. When the parasite was removed from the branchial chamber, the gills appeared splayed and flattened but showed no other signs of disturbance or damage.

Male velvet swimming crabs [Necora puber (L.)] were observed to engage in long and vigorous agonistic interactions to gain possession of a sexually receptive female. The role of agonistic behaviour in male mate competition in this species was examined by investigating the effect of the perceived presence of sexually receptive females on interactions between males. Exposing male crabs to water conditioned by sexually receptive females resulted in prolonged interactions, with a greater incidence of potentially injurious behaviour than interactions between control crabs, exposed only to sea water. Maleconditioned water also resulted in more offensive behaviour, but these interactions were of shorter duration and not significantly different from sea water controls. Agonistic superiority was strongly correlated with contestant relative size when males were exposed to male-conditioned water or sea water, but not when exposed to female-conditioned water. Overall, the results conformed with the general predictions of game theoretic models in relation to the influence of resource value on agonistic behaviour. Crabs were more persistent and probably incurred greater fitness costs in the perceived presence of a sexually receptive female, when interactions may have been resolved on the basis of factors more closely related to actual fighting ability than the relative body sizes of contestants.

The thalassinidean shrimp Calocaris macandreae inhabits complex burrows in marine muddy sediments which are subject to severe hypoxia. In the laboratory, C. macandreae was highly tolerant of anoxia (LT50 = 43 hr) and accumulated l -lactate as the major end-product of anaerobic metabolism. Metabolic recovery of C. macandreae from anoxia was slow; haemolymph lactate concentrations returned to normal levels after approximately 40 hr. Anaerobic metabolism appeared to be initiated only during exposure to severe hypoxia (PO2

The influence of the relative and absolute size of contestants on the agonistic behaviour of velvet swimming crabs was investigated. The agonistic interactions conformed to some of the general predictions from theoretical models of assessment strategy during contests. Crabs usually defeated smaller individuals and the duration and intensity of interactions were inversely related to the size difference between opponents. However, although the intensity of acts tended to increase during the early part of an interaction, there was usually not a progressive escalation, and resolution of interactions was not always preceded by the most intense acts. In addition, following the initial displays, some smaller individuals continued offensively against opponents whose greater size they could probably detect. Information about the size discrimination of Necora puber is lacking, but it appears that a perceived size difference may not always be used to resolve interactions conventionally. In natural populations of these crabs, there may not be a close relationship between size and fighting ability and this may promote more direct assessment of factors such as strength, endurance or motivation. The absolute size of contestants influenced the duration, but not the behavioural content of agonistic interactions. Crabs of large absolute size tended to resolve interactions in less time than small crabs.

The thalassinid shrimp Calocaris macandreae Bell is an important component of the benthic communities of many Scottish sea-lochs. Along with others, this species constructs large, semi-permanent burrows in soft muds. Oxygen availability within burrows constructed by individual C. macandreae in aquaria was found to be severely and chronically low (P02 as low as 15 Torr). The behaviour patterns displayed by C. macandreae in laboratory burrows were analysed using video recordings. In general, behaviour was characterized by low levels of activity, with burrow irrigation by pleopod beating being infrequent and of short duration. During experimental depletion ofoxygen availability, however, burrow irrigation was increased. In view of the hypoxic conditions encountered by C. macandreae, an investigation of respiratory physiology in this species was made. Open and closed respirometry techniques indicated that the rate of oxygen consumption by C. macandreae was low compared to that of most other decapods ...

Towed underwater TV observations at 440 m in the northern Evoikos Gulf, Greece, revealed a soft mud plain heavily bioturbated by the thalassinidean Calocaris macandreae, with Callianassa subterranea and Nephrops norvegicus also present. Ejecta mounds and feeding traces indicated the presence of a large echiuran, provisionally identified as Maxmuelleria gigas. The locality also supported a dense population of a second echiuran, Bonellia viridis, a species not previously recorded as an inhabitant of sedimentary environments.

The branchial ventilatory behaviour of the Red Sea semi‐terrestrial crab Ocypode saratan is described. Examination of scaphognathite beat patterns indicated a number of distinct ventilation strategies, depending on whether crabs were emersed or were immersed in sea water. In the former case, the pattern employed depended on the crab's activity state and on its need to replenish branchial water. The volume of air ventilated by rested crabs was determined.

Histriobdella homari is a polychaete annelid belonging to the Order Eunicida and Family Histriobdellidae. Histriobdella homari is normally found in the gill chambers or among the eggs of the lobster Homarus vulgaris from the English Channel (Roscoff) and in the southwestern part of the North Sea (George & Hartmann-Schroder, 1985). Two independent sightings of H. homari living on the pleopods of Nephrops norvegicus from the Irish Sea and Clyde Sea area are reported.

Various components of swimming performance were measured in uninfected Norway lobsters (Nephrops norvegicus) and compared to animals at different stages of infection by a parasitic dinoflagellate (Hematodinium sp.). Animals showed a progressive decline in overall swimming performance as infection severity increased, with reductions in the number of tail-flips performed, the number of swimming bouts and the total distance travelled by swimming. The velocity of the first (giant-fibre mediated) tail flip and average velocity over the swimming bout were also significantly reduced in infected lobsters. Possible reasons for this decreased swimming performance are suggested and the implications of this for predator avoidance of infected lobsters in the benthic habitat, and for capture of Nephrops by trawl rigs are discussed.