bluuebunny/crossref_metadata_2025 huggingface dataset:
Behaviour and Feeding of the Nassariid GastropodCyclope Neritea, Abundant at Hydrothermal Brine Seeps off Milos (Aegean Sea)
Authors: Southward A.J. , Southward E.C. , Dando P.R. , Hughes J.A. , Kennicutt M.C. , Herrera-Alcala J. , Leahy Y.
Published: May 2009

Field observations and laboratory experiments were made onCyclope neritea, a small (~10 mm diameter) burrowing stenoglossan gastropod with a flattened shell found in very high densities (>200 m2) in Paleohori Bay on the south coast of Milos (Aegean Sea).Cyclope neriteaforms a high proportion of the biomass at seeps in this bay, where the medium to fine sand overlies hot, sulphidic brines. About half the animals were found on the surface in the daytime, an exception to the normal habit of this species which usually emerges from the sediment only at night. TheC. neriteawere aggregated on the thinner bacterial mats over the seeps. In the laboratory,C. neritearemained active for 3 h at sulphide concentrations up to 1 mM, the highest concentration in the interstitial water in the upper 25 mm of sediment at the seeps. Although the species can tolerate elevated salinity and temperature, it shows little adaptation for sulphide detoxification by oxidative pathways. It may survive at the seeps by its behaviour pattern, especially the use of the extensible siphon to access oxic water above the sediment boundary layer, and perhaps by exclusion of sulphide from the tissues.Cyclope neriteaingests large quantities of sand together with adhering bacteria and diatoms, but also scavenges on other animals killed by the extreme conditions of the seeps.
A Long-Term Growth Record Derived from Arctica Islandica (Mollusca, Bivalvia) from the Fladen Ground (Northern North Sea)
Authors: Witbaard R. , Duineveld G.C.A. , De Wilde P.A.W.J.
Published: May 2009

Long-term variations in shell growth of the mollusc Arctica islandica (Mollusca, Bivalvia) from the northern North Sea have been assessed retrospectively using the annually deposited internal growth lines. Relatively young specimens yielded a detailed year-to-year chronology while the growth record of specimens older than 30 y yielded a time series with a length exceeding 100 years. The long-term growth trends demonstrated a marked alternating sequence of periods in which growth was below and above expectation. A 33-y long cycle could be discerned. Since the 1960s the growth patterns in Arctica from two nearby locations were opposite, while they resembled each other in the period before 1960.
Analysis of Oocyte Development and Potential Fecundity of the Squid Loligo Vulgaris from the Waters of Southern Portugal
Authors: Lopes S.S. , Coelho M.L. , Andrade J.P.
Published: May 2009

This study constitutes a first approach of the use of a stereological method for estimating potential fecundity in cephalopods. Squid samples were taken in two regions from the south coast of Portugal. In Olhäo, commercial trawlers provided mainly immature squid during winter. In Quarteira, a summertime traditional jigg fishery provided maturing and mature squid, which were used in the fecundity estimates. A total of 38 female squid, Loligo vulgaris (Cephalopoda: Loliginidae), from all maturity stages were analysed. The results revealed that: (1) the development of the ovaries is monocyclic and the oocyte growth and development is asynchronous; (2) oogenesis proceeds in six histological stages, showing statistically different oocyte maximum diameters; and (3) the best estimate of potential fecundity seems to be obtained by counting all oocytes in the ovaries of the mature females in maturity stage IV
Occurrence of Juvenile Red Mullet (Mullus Surmuletus) on the West Coast of Scotland
Authors: Gibson R.N. , Robb L.
Published: May 2009

Eight individuals of Mullus surmuletus (Teleostei: Mullidae) ≤80 mm total length were captured in shallow water in the Firth of Lorn, western Scotland in August and September 1995. The species is rare on the west coast of Scotland and the occurrence of juveniles is a new record for the area.

The red mullet (Mullus surmuletus L.) is a species whose distribution is centred on the Mediterranean where it forms the basis of a commercial fishery (e.g. Renoñes et al., 1995). Outside the Mediterranean it is found on eastern Atlantic coasts from the Canaries northwards to the English Channel and the southern North Sea where it is ‘moderately common’ (Wheeler, 1969). Further north it is regarded as rare (Wheeler, 1969; Hureau, 1986) and the northern limit is variously given as Scotland (Lythgoe & Lythgoe, 1992) or southern Norway (Wheeler, 1978). Most northern records are from the North Sea (Rae & Wilson, 1954; Rae & Lamont, 1964), presumably reflecting the intensive fishing effort in this area. Records to the west of the British Isles are few and have been summarized by Gordon (1981) and subsequently by Henderson (1986, personal communication), including one from the Faeroes (Blacker, 1977). All recorded occurrences in western Scotland are of adult fish (26–31 cm) caught by commercial fishing vessels and juveniles have never been reported from this area. This note documents (Table 1) the capture of small individuals (N=8) in shallow water off the west coast of Scotland in an area where they had never been recorded previously, despite intensive studies of the local fish fauna since 1970 (R.N.G., personal observation; Gibson, 1973; Gibson et al., 1993). The eight fish were caught on Tralee beach, Ardmucknish Bay, Firth of Lorn, Argyll (56°31′N 5°29′W). The sea bed in this area consists of fine sand (Gibson et al., 1993). It is possible that their occurrence is linked with the unusually warm summer of 1995 allowing juveniles to penetrate further north than usual. Water temperatures at 2–5 m on 29 August, 1995 were 14.3°C compared with a maximum of 13.6°C recorded over the period 1986–1989 (Gibson et al., 1993).
Ultrastructural studies of the elytra ofPholoe minuta(Annelida: Polychaeta) with special reference to functional morphology
Authors: Heffernan P.
Published: May 2009

It has been suggested by Pettibone (1953) and Lwebuga-Musaka (1970) that the elytra of scaleworms may function in respiration, not as the sites of gaseous exchange, but rather the means by which respiratory water currents were created over the dorsum. A role in sensory perception was also postulated (Pettibone, 1953). However, no detailed morphological study accompanied this work. To date the scales of only a few polychaete species have been examined ultrastructurally, and these studies have focused mostly on cuticular features (Anton-Erxleben, 1977, 1981a, b). Considerable attention has been focused on the bioluminescent properties of the elytra of the scaleworm,Harmothoe lunulata(Delle Chiaje) (see Bassot, 1979; Nicholaset al.1981, 1982). Other morphological features ofPholoe minutastudied at the ultrastructural level include gametogenic (Heffernan & Keegan, 1988a) and larval (Heffernan & Keegan, 1988b) stages as well as the digestive tract (Heffernan, 1988). There are several reports on the ultrastructure of polychaete gills (Storch & Welsch, 1972; Spies, 1973; Storch & Alberti, 1978; Menendezet al., 1984; Storch & Gaill, 1986). These works have recently been reviewed by Gardiner (1988). This study describes the fine structure of the scales ofPholoe minutaand the features illustrated here are in agreement with a role in respiration and sensory perception.
The impact of photoperiodicity on hatching of Loligo vulgaris and Loligo forbesi
Authors: Paulij W.P. , Herman P.M.J. , Van Hannen E.J. , Denucé J.M.
Published: May 2009

The influence of photoperiodicity on hatching of Loligo forbesi and Loligo vulgaris embryos was investigated under different experimental light-dark (LD) conditions. The transition from light to dark stimulated hatching and functions as a ‘Zeitgeber’ or synchronizer. Independent of the timing and duration of the dark period most embryos hatched soon after termination of the light period. Embryos which had developed in constant light, showed no hatching rhythm at all. If these embryos were exposed to a dark shock most embryos hatched soon after the onset of darkness. A twilight shock, in which the light was reduced by 50% (i.e. 50 μE s−1 m−2), could not stimulate hatching. Embryos which were kept from stage X on in an artificially controlled LD cycle, preferentially hatch in a period which coincides with the period at which darkness usually occurred when placed in constant illumination from stage XX onwards.
A light microscopic study of the action of sodium orthovanadate on the gills of fresh-water and sea-water eels (Anguilla anguillaL.)
Authors: Kelly K. F. , Pirie B. J. S. , Bell M. V. , Sargent J. R.
Published: May 2009

Gills of fresh-water and sea-water eels were perfused at a constant pressure with physiological Ringer containing 10−6M sodium orthovanadate and examined by light microscopy. The secondary gill filaments were markedly vasoconstricted in both freshwater and sea-water fish although the peripheral blood route around the secondary filaments was unaffected. The central venous space in the primary filament was largely unaffected. Significant constriction of both afferent and efferent arteries on the primary filament occurred. We conclude that orthovanadate vasoconstricts eel gills mainly at the level of the secondary filaments. The study also emphasizes that chloride cells are located on both the primary and secondary filaments of fresh-water gills but solely on the primary filaments of sea-water gills.
Patterns of cell elongation in some Audouinella spp. (Acrochaetiaceae: Rhodophyta)
Authors: Garbary David
Published: May 2009

Patterns of cell elongation and differentiation were examined in a number of Audouinella spp. In all species examined, cells reached their maximum length within a few cells of the apex after which the length (and diameter) of cells became stable. No size differentiation of cells associated with lateral branches was observed, although the basal cells of lateral branches were usually smaller than those in the main axis (except in A. purpurea (Lightf.) Woelkerling and A. parvula (Kylin) Dixon). The position of the lateral branches on branch bearing cells showed little variation and could be used to develop quantitative characteristics for species delimitation. Early stages of development in A. secundata (Lyngbye) Dixon showed an increase in size of apical and subapical cells with plant height, with cell length decreasing toward the base. These developmental features confirm the simple morphology of Audouinella spp, and show that models of growth and differentiation proposed for the Ceramiaceae generally do not apply to the Acrochaetiaceae.
The karyology of the genus Procerodes (Tricladida: Maricola) in British waters
Authors: Galleni Lodovico , Puccinelli Ileana
Published: May 2009

A karyometric analysis of the diploid complement of two species of the genus Procerodes (Tricladida: Maricola), both from British waters, has been carried out

The diploid number of Procerodes littoralis, 2n = 14, was established on mitosis from regenerative blastema and the haploid number n = 7 from spermatocyte I stages. All the chromosomes are metacentric, their centromeric index varying from 47·91 in the chromosome 5 to 38·39 in the chromosome 4.
Evidence for parthenogenetic reproduction in the sea anemone Actinia equina L
Authors: Gashout Salah E. , Ormond Rupert F. G.
Published: May 2009

Contradictory evidence has led to contrasting hypotheses as regards the origin in Actinia equina. L. of the juvenile anemones which may be found being brooded within adults. We have found, in a North Yorkshire population, a very low proportion of males, but these, as well as individuals lacking gonads, often contained young. All young resembled in colour the adults from which they were obtained. Adults maintained in isolation so as to prevent fertilization continued to produce young. Also ova apparently undergoing cell division were found within female gonads. By contrast, small fragments of anemone, although adopting the appearance of larvae, when cultured, do not develop into juveniles. We conclude that within the population studied reproduction is most probably by parthenogenesis.
Studies of the behaviour of the scallopChlamys opercularis(L.) and its shell in flowing sea water
Authors: Thorburn I. W. , Gruffydd L. D.
Published: May 2009

The hydrodynamic properties of the shell ofChlamys opercularishave been investigated and compared with other Pectinidae. The coefficient of lift increases with increasing current speed and angle of attack. Little benefit is gained by increasing the angle of attack beyond 20 °. Allometric changes in shell shape are not sufficient to counteract the increasing weight of the animal with growth. Flow patterns over the shell indicate that a smooth and attached flow over the body of the shell becomes broken up into a turbulent, eddying wake at angles of attack beyond 20 ° and at current speeds greater than 25 cm s−1. The effect of the auricles is to enhance lift at low speeds and to help maintain stability. It is postulated that large turbulence may be further reduced if the dorsal jets act as jet flaps.
Experimental rearing of pilchard larvae, Sardina pilchardus
Authors: Blaxter J. H. S.
Published: May 2009

After initial trials a technique was devised which made it possible to rear about 12 % of newly hatched larvae of the pilchard Sardina pilchardus (Walbaum) to a point well beyond the yolk-sac stage. A survival rate of this order was considered quite satisfactory for larvae which are so small at hatching.
Reactive silicate concentrations observed in the Irish Sea
Authors: Liss P. S.
Published: May 2009

Two hydrographic cruises have been carried out in the Irish Sea during the winters of 1965 and 1966. It has been found that near the Welsh Coast reactive silicate concentrations were remarkably constant and lower than expected. In contrast, near the Irish coast there were marked variations in reactive silicate concentrations and the values found were considerably higher than those for the Welsh coast.
Larval nematodes in the herring (Clupea harengus) from British coastal waters and adjacent territories
Authors: Khalil L. F.
Published: May 2009

Investigations on larval nematodes in herring revealed that Anisakis sp. larvae occurred in the body cavity of 34 % of 5646 juvenile and adult herring examined; and that the infection increased with increase in fish length (age) and varied with the locality, being greater in herring caught nearer to the British coasts. The effect of temperature and salt concentrations on the survival of the larvae and the public health hazards of the larvae were discussed.
Observations of bioluminescence on SOND 1965 Cruise of R.R.S. ‘Discovery’
Authors: Boden Brian P.
Published: May 2009

An investigation of spontaneous bioluminescence as related to sonic-scattering layers was undertaken off Fuerteventura, in the Canary Islands. The apparatus used is described. A definite increase in the magnitude of luminescence at scattering-layer depths is demonstrated. It is shown that the amount of luminescence forward of, and in the net of an Isaacs-Kidd trawl, is very much greater than that either above or below it. A frequency is disclosed within a single flash, and it is hypothesized that this may be a specific property.
Nitrogen turnover in marine and brackish habitats IV. Uptake of the extracellular products of the nitrogen-fixing alga Calothrix scopulorum
Authors: Jones K. , Stewart W. D. P.
Published: May 2009

Long-term growth experiments and experiments using 15 as tracer show that extracellular nitrogen liberated by the blue-green alga Calothrix scopulorum is removed from solution by a variety of algae, fungi and bacteria. Active and passive processes are involved in the uptake, the relative importance of each process varying with the test organism and the extracellular products.
A study of feeding in Scrobicularia plana
Authors: Hughes Roger N.
Published: May 2009

Deposit-feeding by Scrobicularia planaScrobiculariaplana (Da Costa) along the mud surface occurs throughout the period of low tide if the water table remains at the surface. The rate of deposit-feeding is unaffected by the time after emersion at low tide except where excessive drainage prevents feeding along the mud surface, in which case it is possible that animals feed from the sides of their burrows at or below the level of the water table.
Comparative locomotor activity patterns in the portunid crabs Liocarcinus holsatus and L. depurator
Authors: Abelló P. , Reid D. G. , Naylor E.
Published: May 2009

The free-running locomotor activity rhythms of freshly-captured swimming crabs Liocarcinus holsatus and L. depurator have been studied in constant conditions in the laboratory. L. holsatus captured in the intertidal zone of sandy beaches showed strong circatidal activity rhythms with maximum activity at high tide. L. holsatus captured in the sublittoral zone had a clear tendency to show circadian activity rhythms with highest activity during day-time hours. L. depurator occurred only sublittorally and showed circadian activity patterns with highest activity during the night. Exposure to hydrostatic pressure cycles of tidal amplitude and periodicity, entrained strong circatidal activity rhythms in previously arhythmic L. holsatus. This activity pattern also showed a marked circadian component. Exposure to the same regime entrained a circadian rhythm, but not a circatidal rhythm in L. depurator. In the sublittoral zone L. depurator is active mainly during the night, whereas L. holsatus, is active mainly during the day. This may constitute a behavioural mechanism for minimizing competitive interactions between these two sympatric crabs.
Behaviour, irrigation and respiration inEudistylia vancouveri(Polychaeta: Sabellidae)
Authors: Giangrande Adriana
Published: May 2009

To evaluate the relative importance of tentacular crown and body surface in sabellid respiration, experiments were carried out onEudistylia vancouveri(Kinberg, 1867), a long narrow worm living in a permanent tube in the intertidal zone. This species irrigates its tube by peristaltic waves, as do most species of Sabellinae and this allows water circulation inside the tube for body surface respiration.

Measurements of oxygen uptake after amputation of the tentacular crown indicated a reduction of about 80% of the total respiration. This value was higher than that found for other Sabellinae studied. Some predictions about other species were made on the basis of the present observations and of comparison with species having similar aptitudes.

The habit of living in a narrow tube protruding from the sea bottom, as occurs among sabellids, implies some adaptations concerning feeding, excretion and respiration. In the order Sabellida, the prostomium is reduced and fused to the peristomium which usually forms a large tentacular crown (Fauchald, 1977) with both feeding and respiratory functions. Its relative importance in respiration, however, is still little known. Survival after crown amputation suggests that this structure is not essential for respiration; moreover some species can autotomize and regenerate it (Berrill, 1931; Okada, 1934). In sabellids, respiration can in fact occur at the level of the body surface and this is made possible by the flux of the water contained in the tube which is generated by the worm itself: i.e. irrigation. Sabellinae species can actively irrigate their tubes by waves of muscular contraction of the body wall in either direction.
The butterfly squid Stoloteuthis leucoptera in the Mediterranean
Authors: Orsi Relini Lidia , Massi Daniela
Published: May 2009

The presence of Stoloteuthis leucoptera in the Mediterranean is recorded on the basis of three specimens, including an adult male, caught by IKMT and by commercial otter-trawl in the Ligurian Sea. The hypothesis of a recent immigration is discussed.

The list of Mediterranean cephalopods (Mangold Wirz, 1963; Torchio, 1968; Bello, 1986; Mangold & Boletzsky, 1987) includes the Sepiolidae of the subfamily Heteroteuthinae, whose members are supposed to be pelagic throughout their life cycle. Mangold Wirz (1963) recognizes in the Mediterranean fauna the unique species Heteroteuthis dispar, the other authors include H. atlantis Voss, which Voss himself (1955) reported at Messina. To this group may now be added Stoloteuthis leucoptera (Verrill, 1878) a species until now recorded in limited Atlantic areas. Verrill (1881) wrote “This species is an exceedingly beautiful one, when living, owing to the elegance and brilliancy of its colours and the gracefulness of its movements. In swimming it moves its fins in a manner analogous to the motion of the wings of a butterfly.”
Larval metamorphosis of the opisthobranch molluscAdalaria proxima(Gastropoda: Nudibranchia): the effects of choline and elevated potassium ion concentration
Authors: Todd Christopher D. , Bentley Matthew G. , Havenhand Jonathan N.
Published: May 2009

Veliger larvae of the nudibranch molluscAdalaria proximaare triggered to metamorphose to the benthic form by the adult prey bryozoan,Electro pilosa.Ion substitution and supplementation experiments with artificial sea water (ASW) have, however, shown that metamorphosis can be induced by elevation of the potassium ion concentration alone. Approximately 19 mM K+ASW (10 mM ‘excess’) was found to elicit maximal metamorphic responses: 29 and 39 mM K+ASW had no inductive effect. Choline chloride was also found to induce metamorphosis in a dose-dependent manner, with lO M ineffective, 10 M approximately threshold, and 5×10 M to 10 M optimal. Concentrations of choline >10 M were sub-lethally toxic. That the absence of larval metamorphosis on exposure to 29 and 39 mM K ASW was due to inhibition is inferred from interaction experiments with choline: at these concentrations of K, metamorphosis in response to choline could be abolished. Timed-exposure experiments indicated that artificial induction elicited by elevated K and choline involve either separate mechanisms, or different parts of the same pathway. Thus, whilst larvae required to be continuously exposed to 19 mM K ASW in order to complete metamorphosis, those exposed to 10 M choline would subsequently complete development in normal ASW following only 1–2 h exposure to the inducer. Preliminary experiments failed to specify further the nature of the natural inducer, beyond the confirmation that live intact colonies of the bryozoanElectro pilosawill trigger larvae to metamorphose.
Distribution and movements of intertidal butterfish Pholis gunnellus
Authors: Koop J. H. , Gibson R. N.
Published: May 2009

The distribution and movements of intertidal butterfish Pholisgunnellus were studied on the westcoast of Scotland in relation to the foraging tactics of one of its major predators, the otter. Fish were individually tagged and released at low tide in restricted areas of 5 m wide running from the top of the shore towards the sea. Population density increased from 015 fish m" at the top of the shore to 1–1 fish nv in the Laminaria zone. The median total length of all fish examined was 92 mm (N=369) with a very distinct length class of 70–80 mm. There was no relationship between length and position on the shore. Only 24 out of 156 tagged fish were recaptured inside the restricted areas. The recaptured fish had moved a mean of 21 m (SD 1–9 m) in 1–6 days (SD 1–0 days), the directions of movement being randomly distributed. Repopulation rates were studied by removing all fish from three areas of approximately 180 m each. Fish of the same size moved into the cleared areas within two tidal cycles although in much smaller numbers (only 27–52% of the initial populations). Disturbance of the habitat probably played an important role because there was a general decline in numbers in regularly visited areas throughout the experiments. It is concluded that, even allowing for this disturbance intertidal butterfish are mobile and relatively unrestricted in their movements. From the point of view of predators like the otter and the heron, more butterfish are to be caught lower down the shore and each butterfish caught will soon be replaced by another of about the same size.
Comparison of long-term trends in benthic and pelagic communities of the North Sea
Authors: Austen M. C. , Buchanan J. B. , Hunt H. G. , Josefson A. B. , Kendall M. A.
Published: May 2009

Species abundance data for benthic communities, collected during 1971–1988 off Northumberland on the north-east coast of England (western North Sea) and the Skagerrak (eastern North Sea), and pelagic data collected in corresponding areas during 1958–1988 by the Continuous Plankton Recorder (CPR) survey have been subjected tomulti-dimensional scaling ordination. Changes in community structure at the two benthic stations show a high degree of similarity, characterised by a transition in the late 70s. Similarly, there is a less marked transition between the 70s and 80s in pelagic community structure from the eastern North Sea but pelagic data from the western North Sea shows no discernible patterns. Benthic community biomass data, available only for the Skagerrak station, enabled abundance/biomass comparison curves to be constructed which demonstrated a change from un-disturbed communities in the early and mid 70s to moderately disturbed communities in the late 70s and 80s. North Sea macrofaunal abundance, and, in the Skagerrak, macrofaunal biomass appear to co-vary with phytoplankton colour and total zooplankton abundance, although there are insufficient data for statistical testing. A number of factors including eutrophication and/or pollution may be responsible for these changes in community structure.
Variations in time and space: is biogeography relevant to studies of long-time scale change?
Authors: Angel Martin V.
Published: May 2009

Simple community parameters, such as number of species caught and the species diversity of a planktonic group (in this case Ostracoda), have been found to be stable enough in time and space to detect shifts in these parameters likely to be generated by interannual and decadal variation, especially if sampling is conducted at mesopelagic depths. At this time scale, changes in spatial variability will be expressed most clearly as shifts in zoogeographical boundaries. The clearest boundary to be detected in the North-east Atlantic occurs in the vicinity of 40°N, across which is a rapid equatorwards reduction in the total available nutrient as a result of a reduction in the depth of the mixed layer in winter. The boundary at 40°N is marked in satellite images by a sharp reduction in seasonality of surface chlorophyll concentrations. In the planktonic ostracods there is a sharp decline in both species numbers and diversity on the poleward side to a depth of at least 2000 m. If these changes are related to the degree of seasonality in the production cycle, then they can be expected to be climatically controlled. Monitoring this boundary will give an unambiguous signal of any future climate change, natural or anthropogenic, having a significant biological impact on the oceanic ecosystem and on fluxes of material within the water column.
Relationship between a drop of sardine and albacore catches and a relaxation of wind, tested by a Superposed Epoch Analysis
Authors: Mariett Anne Littaye
Published: May 2009

Each summer, in the oceanic north-east Atlantic, a drop in the catch of albacore (Thunnus alalunga Bonnaterre, 1788) is observed for 8 to 10 days at the beginning of August. This temporary decrease of catch per unit effort (CPUE) is related to a relaxation of wind for 5 to 8 days during the previous 8 to 15 days. A similar and significant relationship is also observed in the Atlantic sardine (Sardina pilchardus Walbaum) fishery in a coastal area in the north-east of the Bay of Biscay (France). This indicates that a general ecological process is involved in this relationship between wind and CPUE of two pelagic fish, caught at the sea surface.

The timing of the response of the sardine and the albacore fishery to a relaxation of wind is interpreted in the light of a productivity model. The lack of wind-driven turbulent mixing provides a progressive decrease of the food organisms in the surface layer about 7 days after the wind event. Thus, fish disperse and become less susceptible to capture.

However, particular fertilization processes are involved at the continental shelf-break and the results of the association analysis were not found to be significant for the albacore fishery in this area.

The use of Superposed Epoch Analysis seems to provide a suitable method to analyse such a relationship with a daily time scale.

Comparison of the results of cross correlation analysis used in a previous work with a Superposed Epoch Analysis suggests that further considerations should be given to the use of the latter method infishery science.
Timing of spawning and recruitment in Loligo forbesi (Cephalopoda: Loliginidae) in Scottish waters
Authors: Kong-Lum A. , Pierce G.J. , Yau C.
Published: May 2009

The timing of spawning and recruitment in the squid Loligo forbesi in Scottish waters is described on the basis of data from three sources: monthly samples of squid caught by commercial trawls (1986–1988), egg masses found by fishermen (1987–1991), and statistical data on animals caught by research trawls (1978–1987).

Spawning females were present in samples from December to June, with peak spawning occurring in March. Most records of egg masses were from these months, but eggs were also found in August and September. These results suggest that there is an extended spawning season.

Small squid (≤100 mm dorsal mantle length) were rarely present in commercial samples, but were recorded in research samples almost all year round. Thus there appears to be more or less continuous recruitment into the catchable population.

The results of the present study are consistent with published data from other parts of the geographic range in that there is a regular seasonal peak in spawning, and spawning adults disappear from the population in summer. Further interpretation of the life-cycle of this species is not justified on the basis of current knowledge, and more information is needed on migrations, geographical variation, and lifespan in Loligo forbesi.
Metallothionein induction in Littorina littorea (Mollusca: Prosobranchia) on exposure to cadmium
Authors: Bebianno M.J. , Langston W.J. , Simkiss K.
Published: May 2009

Cadmium uptake, storage and metabolism has been studied in the digestive gland and remaining tissues of the intertidal gastropod Littorina littorea (L). Accumulation of cadmium was linear with time in both of these compartments in individuals exposed to a range of cadmium concentrations (4, 40 and 400 μg Cd l−1).

The subcellular distribution of cadmium in the digestive gland and remaining tissues of Littorina littorea reveals that most of the metal is bound to metallothionein, even in controls, and that cadmium associated with metallothionein increases in proportion to cadmium concentrations in the surrounding water.

Measurements of metallothionein, made by differential pulse polarography showed that, in the digestive gland, concentrations of this metal-binding protein are not significantly affected by cadmium exposure, while in the remaining tissues they are dose-related.

The inherently high levels of metallothionein in the digestive gland of L. littorea explain the role of this tissue as a major site for cadmium storage. However, the lack of significant de novo synthesis of metallothionein in response to cadmium, together with polarographic interferences from high molecular weight thiolic proteins, reduces the value of this tissue preparation as a means of detecting sublethal responses to metals.
Biochemical polymorphism in bass, Dicentrarchus labrax, in the waters around the British Isles
Authors: Child A.R.
Published: May 2009

The bass Dicentrarchus labrax is found in the eastern Atlantic Ocean from Morocco (30°N) to southern Norway (60°N) and in the Mediterranean and Black Seas (Whitehead et al., 1986). Throughout its range the bass is an important commercial species and in the waters around the British Isles it is exploited both by commercial fishermen and by sport anglers.

Since the early 1970s the recorded landings of bass have increased considerably (Pickett & Pawson, 1991). The increased exploitation and the conflict of interest between sport fishermen and commercial bass fishermen have been the subject of a multitude of articles in the fishing press calling for greater stock management. Detailed knowledge of the stock structure was required to provide advice on the management of the UK bass fishery (Pawson & Pickett, 1987).

Prior to 1980, tagging studies were conducted off the southern coast of Ireland (Kennedy & Fitzmaurice, 1972), the south-west of England (Holden & Williams, 1974) and in the Irish Sea (Kelley, 1979).
Morphological and other evidence on the degree of genetic differentiation between populations of Nereis diversicolor
Authors: Hateley Jonathan G. , Grant Alastair , Taylor Susan M. , Jones Neville V.
Published: May 2009

The pattern of paragnaths in Nereis diversicolor differs markedly between 17 populations from eastern and south-west England. There is a substantial heritable component to these differences, and there is no evidence that sediment type during development has any influence on them. Comparisons with previous studies reveal no consistent relationships of paragnath pattern with either sediment type or salinity. Evidence from scanning electron micrographs and correlations between different groups indicates that the anterior and posterior bands of paragnaths have rather different roles in feeding and suggest that the inter-population differences may be adaptations to different diets. The orientation of the jaws confirms that they play an important role only during predation and the handling of large particles, but not during the more usual browsing of the sediment surface.
Phagocyte interactions in echinoid and asteroid echinoderms
Authors: Dales R.P.
Published: May 2009

Phagocytes of the starfishes Asterias rubens L., and Marthasterias ghcialis (L.) (Echinodermata: Asteroidea) phagocytose allogeneic and xenogeneic phagocytes in vivo, but form non-reactive aggregates or syncytia in vitro. The coelomocytes of the sea urchins Echinus esculentus (Mortensen) and Psammechimts miliaris (Gmelin), (Echinodermata: Echinoidea) also form aggregates or syncytia with allogeneic and xenogeneic cells in vitro. Mutual cy totoxicity could not be demonstrated either by enzyme-release or by decrease in numbers of viable cells in cultures of mixed origin as compared with autogeneic controls. The factors which may govern cell recognition and behaviour are discussed.
Metals and melanomacrophages in flounder, Platichthys flesus, spleen and kidney
Authors: Pulsford A.L. , Ryan K.P. , Nott J.A.
Published: May 2009

Kidney and spleen tissues from flounder Platichthys flesus (L.) collected from Neal Point in the estuary of the river Tamar were examined by x-ray microanalysis for the presence of heavy metals within the melanomacrophage centres. Ultrastructurally these centres consisted of groups of pigment-containing macrophages in which melanin was the most prominent pigment, but lipofuscin and haemosiderin were also present. Some of the macrophages also contained irregular metal particles and minerals with associated metals. The metals identified within these inclusions were Ti, Cr, Fe, Co, Ni, Cu, Zn, Sr, Ag, Sn, Ba, La, Ce, Nd, W, Au, Pb, Th and U. The results are discussed in relation to the sediment chemistry of the River Tamar, and the possible routes of uptake by the fish.
Microscopical observations on the excretory organs of the hydrothermal mussel Bathymodiolus thermophilus (Mollusca: Bivalvia)
Authors: Auffret M. , Lepennec M.
Published: May 2009

The pericardial gland of the deep-sea hydrothermal mussel Bathymodiolus thermophilus (Mollusca: Bivalvia: Mytilidae) differs from other mytilids by (1) a narrow lumen and (2) conspicuous polyhedral inclusion bodies in large cytoplasmic vacuoles of the epithelial cells. These inclusions do not contain metals as revealed by microanalysis but are possibly made of proteins. The cells of this gland exhibit a fenestrated basal border which indicates a site of haemolymph ultrafiltration. The kidney is histologically comparable to that of the coastal mussel Mytilus edulis.
Cephalopoda collected on the SOND Cruise
Authors: Clarke Malcolm R.
Published: May 2009

A collection of 185 cephalopods from near the southern end of Fuerteventura(Canary Islands) consists of 18 species and 13 unidentified larval specimens. The collection is particularly interesting because the use of modern closing nets and depth monitoring gear has thrown new light on the depth distribution of some of the cephalopod species concerned. Diurnal migration is described for several oceanic cephalopods for the first time.
On the nutrition and metabolism of zooplankton VI. Feeding efficiency ofCalanusin terms of nitrogen and phosphorus
Authors: Butler E. I. , Corner E. D. S. , Marshall S. M.
Published: May 2009

Total phosphorus and total nitrogen excreted by freshly-caughtCalanus finmarchicus(Gunnerus) andC. helgolandicus(Claus) collected from the Clyde and Plymouth Sound have been measured during spring, summer and autumn. The quantities of phosphorus and nitrogen present in animals, plant foods and faecal pellets have also been determined.
Structure and Seasonal Fluctuations of Rocky Littoral Fish Assemblages in South-Western Portugal: Implications for Otter Prey Availability
Authors: Rui Beja Pedro
Published: May 2009

The fish assemblages of rocky intertidal and subtidal (<3 m depth) habitats of the south-western Portuguese coast were sampled between May 1992 and November 1993, using traps, angling and hand-netting, to investigate their structure and seasonal dynamics. The main purpose of the study was to describe the patterns of prey availability for marine-feeding otters(Lutra lutraL., Mammalia) in south-western Portugal, and to compare these with other areas in Europe. A total of 475 fish of 14 species was captured over 150 d of trapping (788 trap-days), and 1575 fish of 15 species were captured over 24 d of angling (76.3h). Hand-netting was carried out occasionally, to supplement the observations from the other methods, and only 96 fish of seven species were captured. The three methods yielded different patterns of the fish assemblage: giant gobies(Gobius cobitisPallas, 33.7%) and rock gobies (G.paganellusL., 22.9%) were the most frequently trapped fish; corkwing wrasse(Symphodus melons(L.), 81.2%) were the usual species caught by angling; shannies(Lipophrys pholis(L.), 42.7%) and Montagu's blennies(Coryphoblennius galerita(L.), 28.1%) were the most frequently netted species. Conger eels (Conger conger(L.)), giant gobies and shannies showed an uneven distribution along the coast, occurring most frequently in schist shelves, rather than in areas of large sandstone boulders. There was a large seasonal variation, with the catches of most species peaking in winter and early spring, including the majority of those most important in the diet of otters: conger eels, shore rocklings(Gaidropsarus mediterraneusL.), rock gobies and corkwing wrasse. This was also the period when the individuals of several species were heaviest.
Deep-Water Spawning of Atlantic Mackerel Scomber Scombrus, West of Ireland
Authors: Priede I.G. , Raid T. , Watson J.J.
Published: May 2009

Atlantic mackerel (Scomber scombrus L.) were sampled by pelagic trawl over the Porcupine Bank to the west of Ireland between 52°N and 54°N at peak spawning time, between 27 May and 10 June 1992. Distribution of juveniles (age classes 1 and 2) was inversely related to depth, comprising over 90% of hauls close to the coast of Ireland and 20% of the catch on the Porcupine Bank. Egg production increased westwards and was high along the continental shelf edge. Adult spawning fish were found throughout the shelf area and beyond, into waters over 3000 m deep. The results indicate that mackerel spawn over deep water some distance from the shelf edge and may exploit oceanic food resources from deep water.
Development From Polyp to Stauromedusa inStylocoronella(Cnidaria: Scyphozoa)
Authors: Kikinger R. , von Salvini-Plawen L.
Published: May 2009

Within the interstitial Cnidaria, the Hydrozoa dominate, with ten mesopsammic genera (living in the interstitial water of sandy bottoms), while the Anthozoa and Scyphozoa are represented by one genus each (Clausen & Salvini-Plawen, 1986; Bouillon & Grohmann, 1990). The only mesopsammic scyphozoans described so far are the small solitary polyps of the genusStylocoronella, which is represented by two species,S. riedli(Salvini-Plawen, 1966) andS. variabilis(Salvini-Plawen, 1987). Little information is available on reproduction and nothing is known about the life-cycle of these interstitial scyphopolyps. By establishing a culture of the twoStylocoronellaspecies, their development into undescribed stauromedusae could be observed for the first time
Larval Development of the Onuphid Diopatra Marocensis (Annelida: Polychaeta) From The Atlantic Coast of Morocco
Authors: Fadlaoui S. , Lechapt J.-P. , Retiere C.
Published: May 2009

Development in the genus Diopatra has been reviewed and divided into four patterns, ranging from brooding in the parental tube to presumed broadcast spawning (Paxton, 1993). While some information is available for numerous species, the identity of some is uncertain, or the information is only anecdotal. Only three species have been studied in detail. Eggs of D. cuprea are released in a jelly mass that readily dissolves in sea-water (Allen, 1959). Although natural spawning has not been observed for D. neapolitana, Cazaux (1972) was able to fertilize the eggs artificially and culture the larvae. The larvae of both species are lecithotrophic and free-swimming, indicating that they are broad-cast spawners.
Detection of High Levels of Genetic Relatedness in Rock-Populations of an Intertidal Isopod Using DNA Fingerprinting
Authors: Piertney Stuart B. , Carvalho Gary R.
Published: May 2009

Multi-locus DNA fingerprinting was used to determine the degree of genetic relatedness within localized assemblages of the intertidal isopod,Jaera albifrons(Crustacea: Isopoda). This isopod has marsupial development, restricted adult vagility and specific habitat preferences, which will tend to isolate groups of animals on a shore and can potentially maintain the integrity of broods after release from the mother. Total genomic DNA was extracted from six individuals from each of ten ‘rock-populations’ in the South Wales area, restricted withRsal, AlulllandHaelllendonucleases, and probed using a (TCC)5oligonucleotide probe. Band-sharing analysis of the fingerprint patterns indicated significantly higher genetic relatedness within rock-populations (mean within rock-population band-sharing value = 0–374 ±0–023 SE) than between (maximum between rock-population band-sharing value = 0–301 ±0033), and at a level that equates to a relatedness between individuals within rock-populations of slightly below half-sibling status. The significance of such findings, in terms of the potential for localized inbreeding and population genetic structure, is discussed.
Iron Biomineralization in the PoriferanIrcinia Oros
Authors: Meldrum Fiona C. , Heywood Brigid R. , Dickson Dominic P.E. , Mann Stephen
Published: May 2009

Iron-containing precipitates, present within the organic matrix of the poriferanIrcinia oroswere identified as crystalline lepidocrocite (γ-FeOOH) by electron diffraction and57Fe Mössbauer spectroscopy. The crystals were located specifically within the spongin filaments, suggesting that the binding and subsequent accumulation of iron by macromolecules present in these filaments were responsible for mineralization. Iron biomineralization did not appear to serve any specific structural role, but may be involved in biological processes such as detoxification.

It is well recognized that Porifera are active in the biomineralization of calcium carbonate and silica, producing beautiful and intricate skeletons (Simpson, 1984). However, the formation of other biominerals is less well documented. Iron biomineralization has been reported in a few species of keratose sponges (Töwe & Riitzler, 1968; Vacelet et al., 1988), and the mineral has been identified as lepidocrocite (γ-FeOOH). Lepidocrocite is a relatively uncommon biomineral, having previously been identified as only a minor phase in chiton teeth (Webb et al., 1989; Lowenstam & Weiner, 1989).
Oxygen Carriage By the Haemolymph of Hyperiid Amphipods
Authors: Spicer John I. , Morritt David
Published: May 2009

The oxygen content of air-equilibrated haemolymph from three species of hyperiid amphipods, Hyperoche medusarum, Parathemisto sp. and Hyperia galba was similar to that of air-equilibrated sea-water. The concentration of haemolymph protein was low in each case. Both features, taken together with the fact that we were unable to detect the presence of copper in the haemolymph in any of the species examined, suggests that hyperiids, unlike gammaridean amphipods, do not possess the respiratory pigment haemocyanin.

All the information available on the O2-binding properties of amphipod haemolymph has been derived from members of the amphipod sub-order Gammaridea. In common with many other crustaceans (Truchot, 1992), O2 carriage in gammarid haemolymph is facilitated by the presence of the copper-containing respiratory protein, haemocyanin (Spicer, 1994). Unfortunately no comparable data exist for the other major amphipod sub-orders, the Hyperiidea, the Caprellidea and the Ingolfiellidea. Consequently we have examined haemolymph from three species of hyperiid amphipod, Hyperoche medusarum (Miiller, 1777) and Parathemisto sp., from the west coast of Vancouver Island, Canada, and Hyperia galba (Montagu, 1813) from the Clyde Sea area, Scotland.
A Note on Seabed Irradiance in Shallow Tidal Seas
Authors: Bowers D.G. , Tett P. , Walne A.W.
Published: May 2009

(1) The tidal cycle and that of solar elevation interact to produce patterns in seabed irradiance during the day which change over the springs-neaps cycle. In locations where high water springs is at midday, there is a single peak in seabed irradiance in the middle of the day at neap tides and two peaks in seabed irradiance (one in the morning, the other in the evening) at spring tides.

(2) These cycles also interact to produce a springs–neaps cycle of daily mean irradiance, which is relevant to the growth of benthic algae. The pattern of this cycle will also vary from place to place. In locations where low water springs is in the middle of the day the pattern is straightforward: maximum daily irradiance always occurs at spring tides. However, where high water springs is in the middle of the day, the cycle can reverse as the days get longer. The timing of the switch in the cycle depends upon the water clarity.

(3) Variations in attenuation over the springs–neaps cycle will also be important. In the Menai Strait, a springs–neaps cycle in K is often (but not always) observed, higher attenuations occurring at spring tides when seabed sediments are stirred up by the stronger tidal currents. This will reduce seabed irradiance at spring tides and tend to favour greater irradiance at neaps. In our model runs, K was kept constant because at present it is difficult to predict these changes. However, in our observations there is evidence of greater seabed irradiance at neap tides associated with greater water clarity. Variations in cloud cover during the day can also affect the regular cycles predicted by the model.

The authors are grateful to Professor Ernest Naylor for encouragement and for information on animal behaviour and light. Members of the Marine Optics Group at Menai Bridge helped with the sampling during the experimental work in July 1994.