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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 quality deterioration of Norway lobster (Nephrops norvegicus) tail meat was monitored during ice storage. The K-value started at 0.7% and reached a value of 39.7% on day 14. Muscle pH followed a sigmoidal pattern that reached a plateau on day 6. Bacterial load and trimethylamine (TMA) increased only after a lag phase to reach considerable levels by day 14 (5.3 log cfu and 10.2 mg (100 g)−1, respectively). These analytical data were compared with sensory data. Principal component analysis (PCA) indicated that laboratory measures were correlated positively with the smell strength of cooked product (increasingly strong) and negatively with the smell character of raw and cooked product (sour-ammoniacal in raw and neutral in cooked products), flavour and aftertaste (both increasingly bland–bitter). The effects of icing delays on the quality of tail meat were also evaluated. Changes in K-values, microbial load, muscle pH and TMA indicated that the delay to icing should be no more than 4 h (at 16 °C) to ensure that quality is not compromised during subsequent post-harvest storage.

The effects of four different ante-mortem stressors (exercise, emersion, starvation and a patent infection with the parasite Hematodinium sp.) on post-mortem processes have been investigated in the abdominal muscle of Norway lobster Nephrops norvegicus by measuring changes in the pH, the levels of glycogen, l-lactate, arginine phosphate, ATP, ADP, AMP, IMP, HxR, Hx and the adenylate energy charge (AEC) over a time course of 24 h with samples being taken at 0, 3, 6, 12 and 24 h. The acute stresses of intense exercise and 2 h emersion resulted in a premature onset of anaerobic glycolysis, leading both to an enhanced glycogen depletion rate and an early accumulation of l-lactate. The chronic stressors, starvation and parasite infection, resulted in a complete ante-mortem depletion of muscle glycogen and consequently the failure of post-mortem glycolytic fermentation. Post-mortem pH and ATP inter-conversion were significantly altered in chronically stressed animals. Ante-mortem, a rapid, almost compl...

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...

It was found that the striated muscle of the Norway lobster ( Nephrops norvegicus ) does not exhibit the rigor mortis state otherwise typical for this type of muscle. This absence of rigor was investigated, concentrating on changes in the structure, ultrastructure and post-mortem biochemistry of the muscle. Samples were initially fixed for light and electron microscopy at the time of death and at different times post-mortem (3, 6, 12 and 24 h). Protein extracts were obtained in parallel to compare the banding patterns of the myofibrillar proteins using SDS-PAGE. A Western blot was applied to elucidate if myosin – a representative major myofibrillar protein – was degraded post-mortem. And finally, ATP levels in the muscle were analyzed using HPLC. Using TEM imaging it was found that between 12 and 24 h post-mortem at a storage temperature of 10 °C, when rigor mortis should set in (according to the muscular ATP concentrations), an extensive, but rather specific breakdown of myofibrillar proteins occurred. The Z-disks were degraded and the myofibrillar structure was lost. SDS-PAGE and Western blot clearly demonstrated the post-mortem breakdown of myosin. The nature of the observed protein breakdown seems to impede rigor mortis in some way by the activation of at least one of the several proteolytic systems (cathepsins, calpains and others) found in vertebrates and invertebrates. It is speculated that the proteolysis simply overtakes the rigor -inducing post-mortem changes.

Milligan, R. J., Albalat, A., Atkinson, R. J. A., and Neil, D. M. 2009. The effects of trawling on the physical condition of the Norway lobster Nephrops norvegicus in relation to seasonal cycles in the Clyde Sea area. – ICES Journal of Marine Science, 66: 488–494. The fishery for Norway lobster, Nephrops norvegicus, is the most valuable in Scotland, but few studies have examined the physical condition of the animals trawled. This study aimed to determine the extent of physical damage caused by trawling to Nephrops in the Clyde Sea area in relation to trawl duration, sex, size, and moult stage. Longer trawls (2.5–4 h) corresponded to increased damage in “hard” (intermoult) Nephrops compared with short (1 h) or very short (15 min) trawls, but there was no correlation in “soft” (late intermoult or recently moulted) or “jelly” (immediate post-moult) Nephrops. This effect appeared to be limited to Nephrops with a carapace length (CL) of 20.0–29.9 mm. Seasonal effects were also observed, with numbers of jelly Nephrops highest in May 2006, corresponding to a peak in female prevalence in the catches, an increase in the mean CL of females, and greater damage in females. The proportion of females was higher than males from May to September 2006, and it is suggested that this corresponds to female emergence patterns. As quality will be low, it may be pertinent to avoid fishing during the peak emergence period to maximize the quality and profitability of catches.

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...

A study was made of the efficiency of a commercially available hydraulic dredge design in use on the west coast of Scotland and of the annual biomass production of two different razor clam (Ensis spp.) beds within the Clyde Sea area. These two parameters, viz fishing efficiency and population annual production, are fundamentally important to any proper attempt to assess the long term sustainability of a fishery. The hydraulic dredge used in this study was found to have an absolute efficiency of 90.1% when expressed in terms of the collected wet weight biomass, representing the first time that the efficiency of a hydraulic dredge of this nature has been measured rather than simply inferred from track width. This indicates that this dredge design has the potential to remove the majority of a clam population, including undersized immature individuals, within a 45 cm swath in a single tow. Annual production estimates were also made for two separate razor clam beds. One population of Ensis siliqua was located in Irvine Bay and the other two populations (one E. siliqua and one E. arcuatus) occurred in a mixed bed on Hunterston Sands. Each location was sampled quantitatively on a regular basis using the same hydraulic dredge. Dredged areas were measured by SCUBA divers so that the population densities could be calculated for each sampling event. Size-classes within each population were identified from siphonal shell breadth measurements and production estimates were calculated using a size-cohort analysis procedure designed for stocks exhibiting recruitment but that do not have separable age-classes. Production of all three populations was low during the study (1.82–18.08 g AFDW 10 m-2) as were the production/biomass estimates (0.01–0.11). These data indicate that populations of Ensis spp. on the west coast of Scotland are slow-growing and typical of K-selected species. These data highlight the conflicting pressures facing any razor clam fishery: the design of extremely efficient hydraulic gear and the slow-growth of the target species. It is clear that the future commercial exploitation of these species will need very careful management to ensure sustainability and avoid fishery over-depletion.

Morello, E. B., Froglia, C., and Atkinson, R. J. A. 2007. Underwater television as a fishery-independent method for stock assessment of Norway lobster (Nephrops norvegicus) in the central Adriatic Sea (Italy). – ICES Journal of Marine Science, 64: 1116–1123. Norway lobster is of great commercial importance throughout the NE Atlantic and Mediterranean, where it lives in burrows in muddy sediments. The fact that the species is caught in commercial gear only when it emerges from its burrow and the absence of hard structures available for age determination complicate the application of normal fishery-dependent stock-assessment methodologies. This study provides more evidence of the usefulness of underwater television surveys as a fishery-independent technique to assess the Nephrops stocks of the Adriatic Sea. The results are compared with those of previous studies, and the advantages and disadvantages of using such methodology discussed in an Adriatic context.

The pathology and progression of idiopathic muscle necrosis (IMN) in Nephrops norvegicus and possible aetiologies have been investigated. Trawl capture, aerial exposure and handling initiate IMN, and the condition can be induced through periods of aerial exposure alone, in the absence of trawling. Within 24-48 h after trawl capture IMN progresses to a multi-species bacterial septicaemia, with moribund animals exhibiting clinical signs. The aetiology of this condition has been examined using molecular (16S rRNA gene sequencing) and biochemical (standard taxonomic assays, Biolog) criteria to characterize bacterial isolates from moribund and healthy animals. Histopathology of the IMN phase reveals a loss of sarcomeric structure with necrotic lesions containing pyknotic nuclei, fragments of myofibrils and connective tissue elements. In the bacterial phase there is extensive loss of abdominal muscle structure, and the presence of rod-shaped Gram-negative bacteria in the degrading tissues. The results demonstrate that the IMN condition is connected to stressful conditions imposed on N. norvegicus, but involves no pathogenic agents. This is followed by an opportunistic bacterial infection that causes further tissue spoilage. It is believed that the primary cause of both IMN and bacteraemia is imposed stress, but they are expressed in different time courses.

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.

A study was made of the impacts on a benthic megafaunal community of a hydraulic blade dredge fishing for razor clams Ensis spp. within the Clyde Sea area. Damage caused to the target species and the discard collected by the dredge as well as the fauna dislodged by the dredge but left exposed at the surface of the seabed was quantified. The dredge contents and the dislodged fauna were dominated by the burrowing heart urchin Echinocardium cordatum, approximately 60–70% of which survived the fishing process intact. The next most dominant species, the target razor clam species Ensis siliqua and E. arcuatus as well as the common otter shell Lutraria lutraria, did not survive the fishing process as well as E. cordatum, with between 20 and 100% of individuals suffering severe damage in any one dredge haul. Additional experiments were conducted to quantify the reburial capacity of dredged fauna that was returned to the seabed as discard. Approximately 85% of razor clams retained the ability to rapidly rebury into both undredged and dredged sand, as did the majority of those heart urchins Echinocardium cordatum which did not suffer aerial exposure. Individual E. cordatum which were brought to surface in the dredge collecting cage were unable to successfully rebury within three hours of being returned to the seabed. These data were combined to produce a model of the fate of the burrowing megafauna dredged and dislodged in order to collect 10 kg of marketable razor clams.

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.

1. Maerl beds are carbonate sediments, built by a surface layer of slow-growing coralline algae, forming structurally fragile habitats. 2. They are of international conservation significance, often supporting a high biodiversity and abundant bivalve molluscs. 3. Experimental fishing for scallops (Pecten maximus) on French and UK grounds has shown that although large epifauna are often killed, many organisms escape harm as they burrow deeply or are small enough to pass through the dredges. 4. Bivalve dredging is currently one of the main threats to European maerl grounds as it reduces their biodiversity and structural complexity and can lead to long-term degradation of the habitat. 5. Protecting maerl grounds is of importance for fisheries since they provide structurally complex feeding areas for juvenile fish (e.g. Atlantic cod - Gadus morhua) and reserves of commercial brood stock (e.g. Ensis spp., P. maximus and Venus verrucosa). 6. We outline improved mechanisms to conserve these ancient and unique biogenic habitats.

Global positioning system (GPS) -based position data loggers were used in a 4-month pilot study on micro-scale mapping of Nephrops trawler effort in the Clyde Sea area, west Scotland. Position data loggers supplied unbiased, accurate fishing effort data at a scale hitherto unrecorded. Vessels in the survey carried out between 13 and 59 tows per month ( mean =35.3±2.6 S . E . ) with a mean duration of 3 h and 30 min. Fishing effort was expressed as the number of times a trawl passed through a 0.25′ × 0.25′ pixel . The area covered by fished pixels was 1208 km2, with 29% of these being fished on one occasion during the 4-month period. The maximum number of times a trawl passed through an individual pixel was 27. Trawl location data were combined with daily landings obtained from a complementary confidential logbook scheme using geographic information system (GIS) to produce maps of fishing effort, cumulative landings and landings per unit effort (LPUE). The potential for such studies is discussed and recommendations are given for position data logger deployment and logbook schemes.

Demersal fishing gear such as otter-trawls generate large amounts of unwanted by-catch. The Norway lobster ( Nephrops norvegicus ) is the most important shellfish resource in UK waters and although the fishing effort has increased considerably over past decades the ecosystem effects of this fishery have yet to be evaluated. This study provides the first assessment of the catch and discard composition from Nephrops trawls in the Clyde Sea area with particular emphasis on invertebrate discards. Nephrops constituted only between 14 and 23% of the total catch (volume); other invertebrates and fish accounted for the remainder of the catch. On an average, 9 kg of discards were produced per kilogram of Nephrops . The catch composition differed markedly between samples from the north and south Clyde Sea areas. Trawls from the south yielded a significantly higher biomass of Nephrops (30% cf. 4% in the north) and fish discards (55% cf. 36% in the north) whereas catches from the north contained more invertebrates (60% cf. 15% in the south). Crustaceans and echinoderms accounted for up to 83 and 73% of the discards, respectively. Samples from the north also contained a greater variety of invertebrate species (93 taxa cf. 51 taxa in the south). The differences between the two study areas are likely to be a reflection of differing bathymetries, hydrographic conditions and ground types in each area.

The two major field methods (body colour and pleopod index) for the diagnosis of infection in the Norway lobster, Nephrops norvegicus by the dinoflagellate parasite Hematodinium were compared. Using the more reliable method, the pleopod index, which scores infection severity on a four-point scale, infection prevalence data were collected from a single fishing ground in the Clyde Sea area, western Scotland over a continuous period of 31 months. Peak infection prevalence occurs during the spring and is highest in small N. norvegicus [mean carapace length 28.1 (0.67) mm in females and 30.9 (0.50) mm in males] and in females. Mean infection severity increased from 1.050.03 during the low season (July–December) to 2.590.19 by the end of the main infection season (May), highlighting the progressive nature of patent infection over time. Infection prevalence is synchronous between the sexes in some seasons but not in others. Additionally, the proportion of recently moulted, infected males in the late season extends the duration of peak infection prevalence in certain years. Data from two adjacent fishing grounds in the Clyde Sea area also show that infection prevalence depends upon the population structure at a given site – the site with smaller animals showing the higher prevalence. An evaluation of methods for monitoring Hematodinium infection suggests that the pleopod method gives the most accurate estimation of prevalence in field-caught lobsters. 2001 International Council for the Exploration of the Sea

This study has used time‐lapse video recordings to analyze the burrow‐related behaviour of N. norvegicus under a 12 h light: dark regime in aquarium conditions, and compared this with the behaviour of lobsters infected by the parasitic dinoflagellate Hematodinium. Uninfected lobsters performed a higher number of burrow departures, of longer duration, during the hours of darkness than during the light. Infected lobsters performed a relatively constant number of departures of similar‐duration in the light and the dark periods. However, the mean number of departures per day performed by infected lobsters (70 day‐1) was more than double that of uninfected lobsters (30.1 day‐1), while the mean duration of burrow departures performed by infected lobsters (258.5s departure‐1) was more than six times greater than in uninfected lobsters (38.7s • departure‐1). This led to a more than ten‐times increase (from 1.7 to 19.4%) in the percentage of the day spent out of the burrow by infected lobsters. This altered burrow...

Tuck, I. D., Atkinson, R. J. A., and Chapman, C. J. 2000. Population biology of the Norway lobster, Nephrops norvegicus (L.) in the Firth of Clyde, Scotland II: fecundity and size at onset of sexual maturity. – ICES Journal of Marine Science, 57: 1227–1239. The fecundity and size at onset of sexual maturity of Nephrops norvegicus was estimated at different locations within the Firth of Clyde, S.W. Scotland. The ‘‘potential’’ fecundity was estimated from oocyte counts in mature ovaries, while estimates of ‘‘actual’’ fecundity were made from counts of the eggs attached to the pleopods of ovigerous females. Size at onset of maturity of Nephrops norvegicus was estimated from the study of primary (ovary maturity and eggs on pleopods) and secondary (allometric) sexual characteristics. Relationships between potential fecundity and female carapace length were found to conform to a power function (F=aL b ). Comparison of the logarithmic formulations of the relationships for seven locations revealed no differences in power terms, but there were significant differences in the constants. Results suggested that differences in fecundity mainly reflected a geographical variation in oocyte volume (expressed in terms of mean dry weight) which appeared to be related to growth. Where growth rate was characterized by a low value for the asymptotic length of the carapace (L), females appeared to have smaller oocytes and larger size-specific fecundity. Estimates of size at onset of sexual maturity varied over small geographic scales (tens of km) and ranged between 21–34 mm carapace length for females and 29–46 mm for males, the estimate obtained from the different approaches being similar. Size at onset of maturity was positively related to L (p

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.

Rapido trawls are used to catch sole around the coast of Italy and to catch scallops in the northern Adriatic Sea but little is known about the environmental impact of this gear. Benthic surveys of a commercial scallop ground using a towed underwater television (UWTV) sledge revealed an expansive area of level, sandy sediment at 25 m characterized by high population densities of scallops (2·82 m −2 Aequipecten opercularis but fewer Pecten jacobaeus) together with ophiuroids, sponges, and the bivalve Atrina fragilis. Rapido trawls were filmed in action for the first time, providing information on the selectivity and efficiency of the gear together with its impact on the substratum and on the benthos. The trawls worked efficiently on smooth sand with ca. 44% catch rate for Pecten jacobaeus, of which 90% were >7 cm in shell height. Most organisms in the path of the trawl passed under or through the net; on average by-catch species only formed 19% of total catch by weight. Of the 78 taxa caught, lethal mechanical damage varied from 50% in soft-bodied organisms such as tunicates. A marked plot surveyed using towed UWTV before, then 1 and 15 h after fishing by Rapido trawl showed clear tracks of disturbed sediment along the trawl path where infaunal burrow openings had been erased. Abundant, motile organisms such as Aequipecten showed no change in abundance along these tracks although scavengers such as Inachus aggregated to feed on damaged organisms. There were significant decreases in the abundance of slow-moving/sessile benthos such as Pecten, Holothuria, and Atrina. Juvenile pectinids were abundant on the shells of Atrina. The introduction of a scheme of areas closed to trawling would protect highly susceptible organisms such as Atrina and enhance the chances of scallop recruitment to adjacent areas of commercial exploitation.

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.

Around Scotland, coastal stocks of the commercially important Norway lobster (Nephrops norvegicus), particularly those within the Clyde Sea Area (CSA), have for some years been known to be infected by syndiniid dinoflagellate endoparasites of the genus Hematodinium. The prevalences of infected Norway lobsters in trawl samples from the CSA are reported for 1992-1995, together with similar data from a range of Scottish west coast sites in 1992, and from the Irish Sea in 1994 and 1995. In the CSA, infection prevalences declined after 1992 and were higher than those recorded in other sampled areas. Infection by Hematodinium was confined to the first half of the year, peaking in the spring and early summer, with medium-sized and female lobsters showng the highest prevalence. Comparison between CSA sites suggests that infection may be influenced by factors directly related to Nephrops age rather than size. In addition to the usual diel variability in catch, in spring male Nephrops showed diel variability in Hematodinium prevalence in trawl samples (being higher in the midnight samples). Females showed no diel variation in prevalence. Underwater television surveys of Nephrops burrow density and data on commercial landings indicate a decrease in Nephrops abundance in the last decade, which might in part reflect the higher levels of infection by Hematodinium during this time.

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...

The digestive system of the thalassinidean mud-shrimpUpogebia stellatawas investigated using scanning electron microscopy (SEM). Within the lumen of the midgut both filamentous and rod-shaped bacteria were observed. The hindgut microbial populations were dominated by dense mats of epimural rod-shaped bacteria. The gut contents were often dominated by diatoms but also contained bacteria, dinoflagellates, plant and algal fragments. Direct bacterial counts by epifluorescence microscopy along the length of the gut revealed a slight decrease in numbers within the midgut moving from the anterior to the posterior regions, and then a dramatic rise in numbers within the hindgut. Numbers decreased again in the posterior regions of the hindgut. Common in the transient / resident samples (bacterial population when gut contents were present) were enterobacteria and an unidentified fermenter conforming to an isolate named X-ferm. However, nearly 30% of the bacterial isolates remained unidentified. The resident-only bacterial isolates from the gut (determined when the gut was empty) were dominated by the X-ferm bacteria and to a lesser extent by the generaVibrioandAeromonas. With respect to the enzyme capabilities of the gut bacteria, the resident-only collection of bacterial isolates showed much higher levels of amylase, cellulase, chitinase, protease and lipase activity than the transient/resident bacterial isolate collections, suggesting that the indigenous bacteria are likely to play a significant role in the digestion of the gut contents. Thalassinidean shrimps are likely to play an important role in the breakdown of plant and detrital material, and the recycling of nutrients in marine benthic systems.

The abundance and biomass of the Firth of Clyde Nephrops norvegicus stock was estimated using two fishery independent techniques, back-calculation of spawning stock size from larval surveys and production estimates, and burrow counts from an underwater television survey. Larval production estimates were available from two separate investigations in different parts of the Firth of Clyde in 1984 and 1990. The annual larval production estimates from the two studies were divided by a relative density weighted mean fecundity (allowing for ovary resorption and egg loss during incubation) to estimate the numbers of spawning females. Length, weight and sex ratio data were then used to estimate the total stock biomass. The results from the two studies were combined to provide an overall estimate for the Firth of Clyde, of approximately 11,100 tonnes. Counts of burrows, obtained from television camera surveys in 1993, were used to estimate N. norvegicus densities and abundance and the latter value, multiplied by mean weight of individuals from trawl samples, gave a stock biomass estimate of about 8000 tonnes for the Firth of Clyde. The estimates from the two techniques compare reasonably well with recent analytical estimates based on fishery data from the same area. Trawl sampling at the same locations chosen for the TV survey indicated a positive log-linear relationship between burrow density and trawl catch rate suggesting the possibility that, with careful planning, trawl surveys could also be used for stock surveys. There was also a positive log-linear relationship between TV counts of emerged N. norvegicus and burrow density suggesting that the proportion of the population out of their burrows and available to trawling was relatively greater at high densities.

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.

The density, size composition and growth of Nephrops norvegicus were examined at six sites in part of the Firth of Clyde, SW Scotland, between 1990 and 1992. Sampling was carried out using small mesh trawls and by an underwater television camera. The growth of male Nephrops at each site was investigated by analysis of length-frequency distributions using the computer program “Multifan”. Estimates of Nephrops density at each station were obtained from TV counts of burrows and from relative trawl catch rates. Both density measures were correlated and showed a similar pattern between stations, although burrow counts exceeded trawl catches by roughly two orders of magnitude. Marked geographical variations were recorded in both the growth (L 0nfin; and K) and density parameters, and L ∞ was found to be inversely correlated with burrow density, suggesting that growth may be density-dependent. The weighted annual mean carapace length of Nephrops in trawl samples was significantly correlated with L ∞ , suggesting that mean size data may provide a useful indicator of growth variability within and between populations. On the other hand, the maximum carapace length (L max ) of Nephrops in samples was found to provide an unreliable estimate of L ∞ . The results are discussed in relation to possible environmental influences on growth and population density.

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.

Sulphide occurs widely in marine sediments and is highly toxic to most organisms. Its principal poisoning effect occurs at extremely low concentrations and is the result of inhibition of mitochondrial cytochrome c oxidase. Mud-shrimps (Crustacea: Thalassinidea), construct burrows in sublittoral muddy sediments. The sediment in which they burrow is markedly reduced and conditions within the burrow are usually hypoxic and hypercapnic. Field measurements indicate that the shrimps may be exposed to potentially toxic levels of sulphide in the burrow water (range 0–206 μM, N=37). Laboratory experiments carried out onCalocaris macandreae, Callianassa subterraneaandJaxea nocturnahave shown that these species have a high tolerance of sulphide. An oxygen dependent detoxification mechanism exists to defend cytochrome c oxidase from sulphide poisoning. The main detoxification product of this mechanism is thiosulphate which accumulates rapidly even during brief exposures to low concentrations of sulphide. Sulphite also appears as a secondary detoxification product. Aerobic metabolism can be maintained even under severe hypoxia and toxic sulphide conditions. The mud-shrimps switch to anaerobiosis when the detoxification mechanism is saturated. These data indicate that mud-shrimps are physiologically adapted to tolerate elevated levels of sulphide that they may encounter in their natural habitat.

This paper summarizes the available information on the distribution and biology of Maxmuelleria lankesteri. This large echiuran was described almost a century ago but its local abundance and potential importance as a bioturbator were recognized only recently. The species is widespread around the British and Irish coasts, most commonly in fine muds. A deep-burrowing, nocturnal deposit feeder, M. lankesteri is unlikely to be seen by divers, but its presence can be deduced from the form of ejecta mounds and proboscis tracks. The worms are very difficult to capture intact. Body size in a sample from Loch Sween, Argyll, was approximately normally distributed. Very small individuals are rarely found. Developing oocytes were found in the coelom over the spring and summer. Mature eggs accumulate in the gonoducts, with maximum loads found from October to December, possibly indicating a single annual spawning during the winter. Despite intensive examination of a large number of adult females, no dwarf males were found, leaving open the question of their existence. The large, yolky eggs indicate lecithotrophy or direct development. Larval stages have not been recognized. The apparent scarcity of developmental stages and of very small adults suggests that recruitment may be sparse and infrequent.

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.

Hematodinium infections in Norway lobster Nephrops norvegicus from the Clyde Sea area (CSA) population, Scotland, UK, have previously been undetected in summer. This study aimed to establish if the CSA is actually devoid of infected N. norvegicus in this season. Two PCR assays, an ELISA and 2 tests that detect only patent infection (pleopod and body colour methods) were applied in a 21 mo study. Patent infection was seasonal, appearing predominantly in spring, while subpatent infection diagnosed by ELISA and PCR was highly prevalent in all seasons. Generalised linear modelling supported this assertion, as sampling in September and February significantly increased the probability of finding infected N. norvegicus (p < 0.01); infections were predominantly subpatent and patent respectively, at these times. Therefore, Hematodinium seasonality in N. norvegicus populations is likely to have been an artefact of insensitive diagnostic tests. Light Hematodinium infections were found using PCR assays when patent infections were at their most prevalent and intense, suggesting that infection develops at different rates in different N. norvegicus individuals and that only a portion of the total number of infected N. norvegicus die within a single year. These new data were added to a long-term data series for the CSA (1990 to 2008), which showed that after an initial 5 yr epidemic period, prevalence stabilised at 20 to 25%. Comparisons with ‘susceptible-infected-recovered/removed’ (SIR) models suggest that this high prevalence is maintained through high birth rates of susceptible host N. norvegicus.

A previously unrecorded surface trace is described from a towed underwater TV survey of the southern Clyde Sea area. The trace comprises a mound with a single central opening, surrounded by a shallow trench with between 4 and 7 openings. The feature is approximately 10 cm in diameter, and occurred in pairs in the majority (76%) of observations. Spatial variability in the density of the feature was noted with densities estimated between 0.00134 and 0.0193 per m2. The spatial distributions were analysed using quadrat and nearest-neighbour techniques, and were not found to be significantly different from random.

The echiuran worm Thalassema thalassemum (Echiura: Echiuridae), is a deposit-feeder which uses its proboscis to collect sediment particles for ingestion. The proboscis is highly extensible and is used with dorsal surface downwards to skim particles from the sediment surface. Alternatively, the distal portion of the proboscis is arched over and the ventral surface of the tip is held against the sediment surface where ciliary movement facilitates particle collection. These methods are used in combination and collected material is moved back along the proboscis, the edges of which are rolled to form a closed tube. Burrows appear to be U-shaped with one predominantly inhalant and one exhalant opening. Faecal pellets are periodically ejected forming small mounds around exhalant openings and mean rates of 1·83 and 2·80 g dry wt d−1 were measured suggesting that, in sufficient densities, this species could make a significant contribution to macrofaunal bioturbation.

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 structure of burrows of the Norway lobster Nephrops norvegicus was examined through resin casting. 17% of burrow casts in Loch Sween, Scotland, showed evidence of adult-juvenile complexes, whil...

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.

Surface activity of the deep-burrowing echiuran Maxmuelleria lankesteri (Herdman) was observed in Loch Sween, Argyll (Scotland, UK) using underwater television. Activity, consisting of proboscis emergence and sediment venting, was observed in all seasons. Proboscis emergence was strictly nocturnal, occurring on average on one night in two. Emergence occurred at irregular intervals during the night, with no consistent rhythmicity. Feeding extensions of the proboscis usually lasted about 10 min, but were often curtailed by accidental contact with ophiuroids or other epifauna. The extending proboscis skims off the top layer of sediment, then rapidly pulls the collected material into the burrow. Animals showed a capacity to select material from particular areas within the feeding radius. The feeding strategy may be to accumulate several loads of sediment in the burrow, then selectively ingest material over the following day. Large volumes of sediment were often vented from burrows, either in a fine suspension...

1. 1. An increase in temperature between 5 and 15C resulted in progressive increases in oxygen consumption (Mo2) and in the rates of heart beat and scaphognathites. Exposure to higher temperatures (20C) was accompanied by a reduction in Mo2, heart and scaphognathite rates. At these temperatures, the animals appeared to be stressed and prolonged exposure frequently resulted in death. 2. 2. Both M. rugosa and M. sarsi were able to maintain their Mo2, independent of Po2, over a wide range of oxygen tension (P = 40–55 Torr). During hypoxia, there was a pronounced increase in heart rate and scaphognathite rate but, at oxygen tensions below the Pc, both decreased sharply. Neither species was very tolerant of total anoxia; M. rugosa could survive for up to 8 hr, but for M. sarsi, survival was limited to only 4 hr. 3. 3. The oxygen and carbon dioxide transporting properties of the haemolymph were also studied. Values for the in vivoPo2, of the pre- and post-branchial haemolymph were 38 ± 9 and 86.2 ± 11 Torr, respectively, in M. rugosa. The oxygen affinity of the haemocyanin of both species was quite low (at 10C and pH 7.8, P50 = 20.3 and 49.6 Torr in M. rugosa and in M. sarsi, respectively) and exhibited a moderate Bohr effect (θ = −0.43). 4. 4. Oxygen affinity was found to be temperature sensitive (ΔH = − 25.5 and −33.6 kJ/mol in M. rugosa and M. sarsi, respectively) but the magnitude of the Bohr effect did not change significantly with increasing temperature. The haemolymph of both species had a similar buffering capacity (β = Cco2/Pco2 =3.4 mmol/l/ Torr) which was also unaffected by temperature. The haemolymph of these species also exhibited a moderate Haldane effect.

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.