bluuebunny/crossref_metadata_2025 huggingface dataset:
The Annual Cycle of Nutrients in the Menai Straits
Authors: Ewins P. A. , Spencer C. P.
Published: May 2009

The annual cycle of silicate, nitrate and phosphorus in the waters of the Menai Straits is described. The concentration of all these nutrients in these waters is apparently markedly affected by occasional incursions of high-salinity low-nutrient water. The concentrations of nitrate-nitrogen tend to show a general increase throughout the winter months as a result of cumulative contributions from land drainage and run off and the absence of appreciable biological utilization. In contrast, an equilibrium concentration of reactive silicate is maintained over this period following the initial autumnal increase in the concentration of this component. The annual cycle of phosphorus in these waters is also anomalous. Relatively high equilibrium concentrations of this nutrient are maintained during the summer months and unexpectedly low concentrations occur in winter. In conjunction with the biological removal of relatively large amounts of nitrate-nitrogen, this causes anomalously high apparent N: P biological utilization ratios. It is difficult to explain the observed variations in the concentration of phosphate in these waters solely in terms of the equilibrium between biological assimilation and regeneration and advective processes.
Some Studies on the Bioluminescence of the Euphausiids, Meganyctiphanes Norvegica and Thysanoessa Raschii
Authors: Doyle Jean D. , Kay R. H.
Published: May 2009

A series of experiments (1963) illustrates the stimulatory effect of 5-hydroxytryptamine on the bioluminescence of Thysanoessa raschii (M. Sars). A further series (1966) shows the effect of 5-HT and of the cinnamanilide anti-serotonin, Squibb 10,643, on the bioluminescence of Thysanoessa raschii and of small Meganyctiphanes norvegica (M. Sars), with and without stimulation by a bright light flash. The suggestion that 5-HT, or something chemically similar, may prove to be a part of the natural control system of the bioluminescence in these euphausiids is endorsed.
Gametogenesis and Breeding in a Natural Population of Nereis Virens
Authors: Brafield A. E. , Chapman G.
Published: May 2009

Studies of a natural population of N. virens Sars at Southend reveal that the oocytes take a little over a year to mature. After a period of relative quiescence they grow rapidly between September and December and then increase little in size until early May. Within a given specimen small oocytes are more variable in size than large ones. Sperm develop fully from coelomic sperm plates in about eight months, and are mature by the beginning of May. There is a period during which they are characteristically clumped in quartets.
The Efflux of Sodium from Single Crab Muscle Fibres
Authors: Bittar E. E. , Caldweix P. C. , Lowe A. G.
Published: May 2009

The efflux of radioactive sodium injected into single muscle fibres from the leg muscles ofMaia squinado(Herbst) has been studied. The efflux is reduced by the sodium-pump-inhibitor ouabain and by removal of the external potassium. An increase in external potassium leads to a transient increase in sodium efflux which is then followed by a decline to a value well below the normal level. Externally applied caffeine and injected calcium can, under certain conditions, cause a lowering of the sodium efflux which may be associated with contraction of the fibre. The injection of lactate and pyruvate did not affect the efflux. The results are discussed in terms of the possible effects of the structure of the fibre on the efflux.
Platymonas Impellucida Sp.Nov. From Puerto Rico
Authors: Mclachlan J. , Parke M.
Published: May 2009

The morphology and microanatomy of Platymonas impellucida sp.nov. have been investigated using light and electron microscopes and unusual stages of cell division studied. The anatomical features closely resemble those recently described for Platymonas convolutae (cf. Parke & Manton, 1967). As in that species the pyrenoid is penetrated from many directions by cytoplasmic canaliculi lined with the double plastid membrane but unlike that species a starch shell is not developed around the pyrenoid. In whole cells of P. impellucida therefore, it is extremely difficult, in most cases impossible, to detect the presence of the pyrenoid. This new information on the absence of a starch shell in a member of the Prasinophyceae is of importance since pyrenoid structure appears to be of major importance for taxonomic purposes. Apparent fusion stages have been shown to be a variation in vegetative division not previously encountered in the genus Platymonas.

Introduction

Recent studies on members of the Prasinophyceae have assisted greatly in characterizing this class of green-pigmented algae although the limits are not as yet entirely defined. Fine-structure investigations have, in addition, elucidated certain features of generic significance. The genus Platymonas is now well described and can be unequivocally distinguished from Prasinocladus, a closely related genus. Previously these two genera were separated on the presence or absence of non-motile dendroid colonies, but such colonies are now known in both genera (Parke & Manton, 1967).

The remaining significant diagnostic generic characteristic is the structure of the pyrenoid. In Platymonas the branched canaliculi invading the pyrenoid either from a direction facing the nucleus (Gibbs, 1962; Manton & Parke, 1965) or from many directions (Parke & Manton, 1967) contain cytoplasm rather than protrusions of the nucleus as in Prasinocladus (Parke & Manton, 1965).
Observations on coastal fish fauna during a spring bloom of Phaeocystis pouchetii in the eastern Irish Sea
Authors: Rogers S.I. , Lockwood S.J.
Published: May 2009

Unusually high densities of juvenile flatfish in some areas of a nursery ground, and complete absences from other areas, were associated with a dense bloom of the colonial alga Phaeocystis pouchetii along the coast of North Wales. A possible explanation for these movements, and for the presence of patches of anoxic sediments, is proposed.
Catches and geographical distribution of selachians on the western coast of Brittany
Authors: Rousset Jean
Published: May 2009

In this study the selachians were captured monthly on inshore grounds (10–30 m deep) with a beam-trawl over ten years (1975–1984), mainly in the Bay of Douarnenez, the Roads of Brest and the Bertheaume Cove area (west Brittany). Catches were composed of five species, accounting numerically for 6–5% of the mean catch of the trawled fishes, but reached up to 20% in Bertheaume Cove. On account of the adaptability to different bottom substrates Raja clavata is the most common species. Raja microocellata is uncommon except in the Cove of Bertheaume where it represented half of the selachian biomass captured.
Moulting and mating in Lepeophtheirus pectoralis (Copepoda: Caligidae)
Authors: Anstensrud Morten
Published: May 2009

Prior to moulting, the preadult Lepeophtheirus pectoralis produces a temporary frontal filament which attaches the animal to the surface of the host during ecdysis. This filament is extruded from a frontal organ previously thought to have a chemoreceptory function. During ecdysis the exuvium splits at the anterior margin and is shed posteriorly by contractions of the body. After hardening of the exoskeleton the copepod detaches itself from the frontal filament and is free-living on the host during intermoult. Males in precopula position hold on to the dorsal side of the female, with the second antennae grasping the anterior end of the female's genital complex. During the ecdysis of the female, most males release their hold on the female, and are usually found close to her on the host. Copulation occurs between an adult male and an adult female with a hardened exoskeleton. In the copula position the male holds on to the female's genital complex with the second antennae, but now on the ventral side of the female. Two spermatophores are extruded and then transferred simultaneously to the female with the aid of the second pair of swimming legs. Tubes originating from the spermatophores connect them to the orifices of the receptaculum seminis. These tubes seem to grow out of the spermatophores after expulsion. After copulation, the male retains a precopula position before releasing the female. No agonistic behaviour has been observed between a precopulating/copulating male and additional males. However, during the ecdysis of the female, a new male may take over the female, but mating does not seem to be assortative for size in Lepeophtheirus pectoralis.
Distribution of intertidal isopods in relation to geographical changes in macroalgal cover in the Bay of Biscay
Authors: Arrontes Julio , Anadón Ricardo
Published: May 2009

The distribution of intertidal isopods with respect to algal species was investigated over a range of 250 km on the shores of north Spain. A survey of 25 localities included three zones with a distinct composition of algal species: a western zone comprising shores facing Atlantic waters and the outer part of the Bay of Biscay; a narrow transition zone (about 70 km in length); and an eastern zone extending to the inner part of the Bay of Biscay. Thirty two isopod species were collected, 11 of which were present in high densities. Response to geographical change was observed to occur clearly in three species,Ischyromene lacazei, Idotea pelagicaand I.baltica, and to a lesser degree in I.granulosa; the former two and the latter two were abundant in the eastern and western zones respectively. All four species were found to be closely associated with macroalgae species which display geographical changes in abundance (e.g. Laminaria ochroleucaandComllina elongata). In addition,Idoteaspecies were found to inhabit a reduced number of algal species compared with other European shores. Spanish shore of the Bay of Biscay probably constitutes the geographic limit of the distribution of the four species. A sampling artefact might also be responsible to some extent for the patterns of distribution observed. Differences in the physico-chemical properties of sea water along the coast and circulation of coastal waters are not thought to influence the distribution of isopods.
The use of artificial substrates in monitoring mussel (Mytilus edulis L.) settlement on an exposed rocky shore in the west of Ireland
Authors: King P.A. , Mcgrath D. , Britton W.
Published: May 2009

Artificial substrates were used to monitor Mytilus edulis L. settlement on an exposed rocky shore at Ballynahown, on the west coast of Ireland, from August 1984 to September 1985. Flat nylon domestic pan scourers proved to be good collectors of mussel recruits. The appearance of new modes of 300 µn shell length at times of increasing density of colonising mussels indicated direct settlement of mussel larvae from the plankton onto the pads. These modes appeared in September 1984, May 1985 and August 1985. Direct settlement periods followed the known main spawning times of adult mussels at the study site, March-April and July-August, and are consistent with settlement times ob-served on filamentous algae and adult beds on the same shore. Results from the study show that mussels of primary settlement size, 250–400 im shell length, were available to colonise newly deployed pads throughout the investigation. Furthermore, cohorts of larger mussels recruited to the pads during much of the year. The possible source of these recruiting mussels is discussed.
Jakoba libera (Ruinen, 1938), a heterotrophic flagellate from deep oceanic sediments
Authors: Patterson David J.
Published: May 2009

An account is given of a flagellated protist isolated from Atlantic sediments at a depth of 1500 m. The organism forms part of the microbial food web by consuming suspended bacteria. The organism was originally described by Ruinen as Cryptobia libera. On the basis of its ultrastructure, assignment to the genus Cryptobia is regarded as inappropriate, and Jakoba is proposed as a new generic vehicle.
Introduction and oxidation of catechols during the formation of the skate (Raja erinacea) egg capsule
Authors: Koob Thomas J. , Cox David L.
Published: May 2009

Tanning of theRaja erinaceaegg capsule occurs after secretion of capsule precursors from the nidamental gland and involves the introduction of catechols and their subsequent oxidation to quinones by catechol oxidase. At the time of secretion and assembly of capsular precursors in the nidamental gland, the capsule is white, contains no catechols and lacks chemical and mechanical stability. Following formation in the nidamental gland, catechols accumulatein uteroin parallel with colour development. An inactive form of catechol oxidase is incorporated in the capsular matrix at the time of secretion. Catechol oxidase activity increases concomitantly with increasing catechol content and colour development.
Investigation into the State of Preservation of the E.T. Browne Collection of Hydromedusae
Authors: Moore S.J.
Published: May 2009

A comparative study of the state of preservation of hydromedusae has been made based on a collection that has been preserved for 80–90 years. A report has been compiled in tabular form concerning the state of the collection in relation to the present pH of the preserving fluid. Recommendations are made based upon which fixative and preserving fluids have proved to be best for long-term storage.
A model for ascidian development and developmental modifications during evolution
Authors: Jeffery William R.
Published: May 2009

Ascidian development is reviewed and a model is presented for specification of the larval body plan and cell fate during embryogenesis. The model involves the combined activity of determinants inherited from the egg and inductive cell interactions in the embryo. It is suggested that there are four determinant systems in the egg which are segregated to different blastomeres during cleavage. The ectodermal, endodermal, and muscle determinants specify cell fate autonomously, while the axial determinants initiate cell-shape changes at gastrulation and generate a cascade of inductive activities establishing the larval body plan. In the proposed signalling cascade, the endoderm induces notochord by generating a planar inductive signal late during the cleavage phase, and the notochord cells in turn induce the nervous system by generating a vertical inductive signal in the overlying ectoderm during gastrulation. Ultraviolet (UV) irradiation experiments are described which suggest that axial and muscle determinants exhibit UV-sensitive components resembling nucleic acids and proteins, respectively. The model is evaluated in terms of developmental changes during the evolutionary transition from indirect to direct development. This transition can be explained according to the model by loss or inactivation of the muscle determinants and modification of the inductive activities generated by the axial determinants. These changes are supported by recent studies of embryogenesis in direct-developing ascidians.
The initial development of gangliar rudiments in a posterior position in mytilus galloprovincialis (Mollusca: Bivalvia)
Authors: Raineri M. , Ospovat M.
Published: May 2009

Histochemical methods for cholinesterase activities were applied to embryos and early larvae of the marine mussel Mytilus galloprovincklis Lamarck (Mollusca: Bivalvia: Mytilidae) and demonstrated that the cerebral ganglia, which are generally accepted as the first differentiating ganglia, appear after two bilaterally symmetrical nerve rudiments have developed in a posterior position prior to the trochophore stage. They are intimately associated with non-nervous superficial cells in two structures which have features of sensory organs.
Horizontal distribution and retention of Owenia fusiformis larvae (Annelida: Polychaeta) in the Bay of Seine
Authors: Thiébaut E. , Dauvin J.-C. , Lagadeuc Y.
Published: May 2009

Between 8 May and 3 June 1987 horizontal distribution of Owenia fusiformis larvae (Annelida: Polychaeta) was studied in the eastern part of the Bay of Seine on two spatial scales to determine the role of larval dispersal by hydrodynamic factors on the population dynamics of a benthopelagic species. Larval dispersal occurred in two main directions, north-west and north-east, according to the residual tidal circulation. There was a substantial transport of larvae to a distance of 30–40 NM (48–65 km) from their emission point, resulting in a sizeable loss of larvae to the adult population. However, their densities were low in comparison with those observed in the eastern part of the bay, near the adult population. Larval densities remained highest near the adult population, principally under the influence of tidal processes. In contrast, there was a significant wind-induced larval movement at a time scale of a few days. The action of wind at a time scale of one month, the duration of larval life, appeared to be insignificant for dispersal in 1987 because of the frequent changes in wind direction. Climatological data collected between 1951 and 1980 showed that the wind effect observed in 1987 is probably typical of most years. The horizontal transport of Owenia fusiformis larvae, combined with the ontogenic vertical migration observed previously, causes a retention of these larvae in the eastern part of the Bay of Seine; this favours recruitment and may be one of the factors explaining the temporal stability of the adult population.
Observations on the biology of a rare British marine amphipod: Monoculodes gibbosus (Crustacea: Amphipoda: Oedicerotidae)
Authors: Beare D. J. , Moore P. G.
Published: May 2009

To date, the oedicerotid amphipod Monoculodes gibbosus Chevreux, 1888 is known in British seas from only two individuals collected from Loch Fyne and lodged in the Robertson Collection at Millport (Moore, 1984). Recent intensive research on other species in this family in the Clyde Sea area by one of us (D.J.B.) has resulted in the sporadic capture of further individuals of M. gibbosus (128 individuals in total) from Inchmarnock Water, southern Loch Fyne. This material allows us to expand our knowledge of the species' morphology, live colour, population structure, fecundity, egg size, breeding season, diet and behaviour. Notes on these topics are presented below.
The effect of geographical location on the cellular composition of the mantle tissue of the mussel, Mytilus edulis
Authors: Lowe D. M. , Salkeld P. N. , Carr M. R.
Published: May 2009

The cellular composition of the mantle tissue of Mytilus edulis L. was determined, using quantitative microscopy (stereology) techniques, in three populations of mussels from differing environments, and the data compared. The results indicated that mussels from an estuarine or sheltered coastal environment had a greater proportion of adipogranular tissue than animals from an exposed, open coastal environment. The difference in cellular composition was attributed to differences in nutrient availability in the water column between the various sites. A 15-month transplantation of mussels from an open coast to estuarine conditions resulted in a decrease in the proportion of vesicular connective tissue in the mantle and an increase in gamete production. This suggests that Mytilus edulis can exhibit a high degree of phenotypic plasticity by using not only the more conservative strategy of nutrient storage during periods of high food availability, but also the more opportunistic approach of maximizing gamete production when conditions are favourable.
The development of the female gamete in the endosymbiont-bearing bivalve Loripes lucinalis
Authors: Johnson M. A. , Le Pennec M.
Published: May 2009

The development of the female gonad in Loripes lucinalis (Lamarck) from Brest Harbour (Brittany, France) was examined over a one-year period. Throughout the year, several size classes of eggs were observed, and spawning was seen to occur twice. A major spawning occurred in May leaving the gonad completely empty in June. A minor spawning is also thought to have occurred between the November and December sampling periods. These spawnings do not seem to correlate with the classical environmental factors often associated with gametogenesis and spawning, namely temperature and chlorophyll a levels. The energy for gametogenesis seems to be obtained from the transfer of metabolites to the oocytes via specialized follicle cells. These metabolites are believed to be of heterosynthetic origin. An inverse relationship exists between the thickness of the follicle cell epithelium and the occupancy level of the gametes. During periods of gonadal proliferation, these cells represent the nutritive cells of the gonad, but during periods of non-proliferation they make up a somatic tissue used for metabolite storage until conditions are adequate for gonadal development.
The orientation of muscle fibres in the myomeres of fishes
Authors: Alexander R. McN.
Published: May 2009

The superficial red muscle fibres of gnathostome fishes run more or less longitudinally, but the deeper muscle fibres are arranged in complex three-dimensional patterns in which some of them make angles of 30° or more with the long axis of the fish. There are two basic patterns, of which one is found in all the myomeres of selachians, primitive bony fishes,AnguillaandSalmo. In the other teleosts which were examined this pattern is restricted to the last few myomeres, and a quite different pattern is found more anteriorly.

In a fish with muscle fibres running longitudinally the lateral fibres would be able to contract far more than those near the vertebral column. However, from mathematical analyses included in this paper it appears that both the patterns which have been found should result in all the white fibres in a myomere contracting to a fairly similar extent when the fish bends. This seems likely to be advantageous because a muscle fibre of given intrinsic speed produces maximum power output at one particular rate of contraction.

A given rate of contraction of the muscle fibres results in faster bending if the fibres are arranged in the typical teleost pattern than if they are arranged in the selachian pattern.

The selachian pattern is probably retained in the caudal peduncles of teleosts because the faster bending is obtained only at the expense of weaker bending moments. The caudal peduncle is slender and would be less able to transmit large forces to the caudal fin if the teleost pattern of muscle fibres were continued to its posterior end.
Physiological ecology ofPatella. III. Desiccation effects
Authors: Davies P. Spencer
Published: May 2009

Experiments were carried out to assess the importance of desiccation during tidal exposure upon the vertical distribution of the intertidal limpets Patella aspera and P. vulgat vulgata. The rate at which water is lost during desiccation varies inversely with body size.
The gregarious behaviour of the larvae ofOstrea edulisL. at settlement
Authors: Bayne B. L.
Published: May 2009

The settlement behaviour of the larvae ofOstrea edulishas been examined in the laboratory. Preliminary experiments indicated that high light intensities (1250 lux) and food-cell concentrations (100,000 cells/larva) stimulated settlement, but varying the temperatures within the range 19–23 °C had little effect.
Studies in situ of the primary production of an area of inshore antarctic sea
Authors: Horne A. J. , Fogg G. E. , Eagle D. J.
Published: May 2009

The primary productivity of an area of inshore sea in the South Orkney Islands was measured using in situ techniques in two consecutive seasons. Liberation of extracellular products of photosynthesis occurred, accounting for about 1 % of the total carbon fixed at the depth of maximum photosynthesis but rising to 38 % or more when photosynthesis was inhibited at high light intensities.
Studies on the growth of Phaeodactylum tricornutum V. the relationship to iron, manganese and zinc
Authors: Hayward J.
Published: May 2009

A study has been made of the relationship of Phaeodactylum tricornutum (Bohlin) to iron, manganese and zinc. Evidence is presented showing that, in batch culture, the three elements behave differently as regards their uptake into the cells, the amounts present in the cells and their distribution between cells during the growth of the culture. The implications of these differences are considered.
The Biology ofLaminaria hyperborea. V. Comparison with early stages of competitors
Authors: Kain Joanna M. , Jones Mrs N. S.
Published: May 2009

The responses to light and temperature variations of the gametophytes and early sporophytes ofLaminaria hyperboreanwere compared in culture with those of its main competitors in Britain, namelyL. digitata, L. saccharinaandSaccorhiza polyschides. Some undeveloped gametophytes of all species are able to survive in the dark for at least 80 days.
Nitrogen turnover in marine and brackish habitats III. The production of extracellular nitrogen byCalothrix scopulorum
Authors: Jones K. , Stewart W. D. P.
Published: May 2009

The effects of salinity, light intensity, temperature and pH on the amounts of nitrogen fixed and liberated extracellularly by the marine blue-green alga Calothrix scopulorum (Weber et Mohr) Ag. ex Bornet et Flahault have been investigated.
Redescription of the North Atlantic and Mediterranean Species ofNatatolana(Crustacea: Isopoda: Cirolanidae)
Authors: Keable S.J. , Bruce N.L.
Published: May 2009

The taxonomy of six species and one subspecies ofNatatolana, which have previously been recorded from the north Atlantic Ocean and Mediterranean Sea, is reviewed.Natatolana caeca, N. gallica, N. gracilisandN. neglectaare redescribed from the type material. The location of possible type material ofN. borealisis reported and a redescription of this species is provided, based on material from the type locality.Natatolana neglectavar.imicolais recognized as a valid species.Natatolana schtnidtiis regarded as a junior synonym ofN. imicolabased on comparison of type material and this material is used to redescribe the species. Distribution records for these species are summarized from examination of material held in various collections and a key to separate these species is provided.
Behavioural Responses of Hermit Crabs to Shell Cues, Predator Haemolymph And Body Odour
Authors: Rittschof Dan , Hazlett Brian A.
Published: May 2009

This study tested the hypothesis that predator odours alter behavioural responses of hermit crabs to other chemical stimuli. Stimuli that cause alarm and shell-related behaviour (hermit crab haemolymph and two gastropod flesh extracts), and stimuli that did not cause shell-related behaviour (sea-water and predator haemolymph) were used. Individual hermit crab responses to stimuli were observed in ambient sea-water and predator odour. In the absence of predator odour, hermit crab haemolymph and gastropod flesh extracts stimulated shell grasping behaviour. Locomotion was the major response to sea-water and stone crab haemolymph. Crabs behaved consistently when repeatedly exposed to a particular stimulus. In general, addition of predator odour to mixtures, resulted in decreased shell grasping and increased locomotion. Shell fit was a poor predictor of behaviour for the size range of crabs tested. Hermit crabs respond to, and discriminate, a variety of complex odour mixtures.
Allozyme Evidence for Cryptic Speciation in Sympatric Populations ofNassariusspp. (Mollusca: Gastropoda)
Authors: Sanjuan Andrés , Losada-Perez Marcos , Rolan Emilio
Published: May 2009

TheNassarius reticulatuscomplex (Mollusca: Gastropoda) is a common and morphologically variable organism of the Lusitanian marine province. The taxonomic status of the different morphs has been the subject of considerable debate for over a century. About 50 individuals of eachN. nitidusandN. reticulatusmorphs were collected in November 1994 from the same area (Ria de Vigo, north-west Iberian Peninsula). Preliminary screening by allozyme electrophoresis for 27 enzymes resolved 24 presumptive enzyme loci. There were no deviations from the Hardy-Weinberg expected proportions at most polymporphic loci for any morph. Five and two enzyme loci were completely and partially diagnostic loci, respectively, between the morphs. The genetic identity of morphs (1=0.658 ±0.095) was characteristic of congeneric species. The absence of electrophoretically recognizable hybrids in sympatric populations provides clear evidence that the two morphs are reproductively isolated within the study area. These genetic results corroborate other reported biochemical, morphological and behavioural differences between the morphs. Consequently, these data strongly suggest that the taxaN. nitidusandN. reticulatusmust be considered as separate species.
Field Evidence of Trematode-Induced Gigantism inHydrobiaSpp. (Gastropoda: Prosobranchia)
Authors: Gorbushin A.M.
Published: May 2009

The study of growth rates in the prosobranch snailsHydrobia ulvaeandH. ventrosaunder field conditions showed that growth rate of snails infected by different trematode species is species-specific. Trematodes from the families Microphallidae and Heterophyidae cause gigantic growth whereas species from families Notocotylidae and Bunocotylidae have no effect on growth rate. This discrepancy is attributed to the different pathogenicity of the parasites. However, under experimental conditions with different host population densities the effect of infection byBunocotyle progeneticaeffect varies from a tendency to stunt the growth (under high density) to a significant increase in growth rate (under low density). The effect ofHimasthlasp. (Echinostomatidae) was shown to be population-specific. These findings agree with a previously reported hypothesis that the growth response of trematode-infected snails depends (among other things) on supplement of host-parasite system with food. Trematode infection caused parasitic castration in all studied host-parasite combinations. It is argued that the phenomenon of gigantism in infected snails is a consequence of the reduced sexual ability of the host. The correlation between snail growth rate and penis size of infected males was negative. The correlation between growth rate and penis size was not found in uninfected snails from the same age group
Ecology of the Oceanic Squid Onychoteuthis Banksi and The Relationship Between the Genera Onychoteuthis and Chaunoteuthis (Cephalopoda: Onychoteuthidae)
Authors: Arkhipkin Alexander I. , Nigmatullin Chingiz M.
Published: May 2009

Ontogenetic changes in the body morphology, morphometrics, age, growth, maturation, fecundity, feeding spectrum and parasites were studied in 218 specimens of the oceanic nektonic squid Onychoteuthis banksi and in two specimens of the rare planktonic squid Chaunoteuthis mollis (Onychoteuthidae) caught in the tropical waters between 1977 and 1990. Similarities between the two species in major taxonomic features and in several morphometrical indices suggest that C. mollis is in fact a mature female of O. banksi with degenerated mantle and fin muscles and lost tentacles. Thus, C. mollis will be considered as a lesser synonym of O. banksi. Statolith microstructure analysis reveals that O. banksi is a slow-growing squid with low maturation rates, spending the first 240–260 d of life in the epipelagic zone. The main features of the reproductive strategy include earlier maturation of the males, small eggs (0.2–0.5 mm in diameter by the end of protoplasmic growth), synchronous development of oocytes and high potential fecundity (51,000–205,000 eggs). Onychoteuthis banksi is an opportunistic predator, shifting to a fish and squid diet much earlier and at smaller sizes (20–40 mm ML) than ommastrephid squid. The feeding activity of small and medium O. banksi (20–80 mm ML) is a little higher and that of large O. banksi (80–148 mm ML) is lower than in ommastrephids of the same size. The helminth fauna of O. banksi is impoverished and consists of ‘food parasites’: larval Didymozoidea and Scolex spp. The level of infection is low, only reaching -52 specimens per host in large squid. The nature of the life cycle of O. banksi and possible evolutionary trends in the development of the ‘Chaunoteuthis’ stage for maturation and spawning of females in the deep water are discussed.
Hatching Nauplii of Planktonic Calanoid Copepods from Intertidal Estuarine Sediments
Authors: George C.L. , Lindley J.A.
Published: May 2009

The dominant planktonic calanoid copepods in inshore and estuarine habitats in northern European waters; the Acartiidae, Centropagidae and Temoridae, produce eggs which survive and can remain dormant in the sediments (Marcus, 1996). Eggs of Eurytemora survived passage through the guts of fish larvae, in contrast with eggs of Pseudocalanus (Conway et al., 1994). Eggs of Paracalanus do not survive in sediments (Marcus, 1991). Lindley (1992) suggested that families within the superfamily Centropagoidea, including Eurytemora but not Paracalanus and Pseudocalanus, produce eggs which remain viable in sediments. Previous work on these eggs has been from subtidal sediments, although Naess (1996) showed that calanoid eggs survived in sediments in seasonally drained fish ponds.
Influences on movement and migration in the hermit crab Pagurus bernhardus
Authors: Lancaster I. , Wigham G.D.
Published: May 2009

Dispersion in a littoral population of Pagurus bernhardus in south-west England is shown to be random, with members demonstrating no evidence of site attachment. Movement patterns within the population are shown to be asynchronous and random, and to be dictated by the quantity and quality of each individual's shell contacts. These, in turn, affect the time that individuals spend within the habitat. This implies that population dynamics and residence times are so influenced by the availability of suitable empty gastropod shells that movement and migration in hermit crabs should be regarded as resource-dependent phenomena.
Revision of the family Ammodytidae (Perciformes) in the Mediterranean with the first record of Gymnammodytes semisquamatus
Authors: Sabatés A. , Demestre M. , Sanchez P.
Published: May 2009

The study of the morphological and meristic characters of larval and adult sandeels (Gymnammodytes spp.) collected off the Catalan coast (NW Mediterranean) has revealed the co-occurrence of G. cicerelus and G. semisquamatus in the Mediterranean. The geo-graphical distribution of G. semisquamatus had hitherto been thought to be limited to the European Atlantic coasts. The comparative analysis of specimens of G. semisquamatus from the Mediterranean and from the North Atlantic has demonstrated a marked latitudinal cline in the meristic counts. An exhaustive overview is presented of the bibliography referring to the Ammodytidae family in the Mediterranean, and the validity of the numerous references is discussed. Finally, it has been shown that the accepted description of G. cicerelus included the two species: G. cicerelus and G. semisquamatus. In the present paper an up-to-date diagnosis of both species is presented.
Photosynthetic carbon metabolism of size-fractionated phytoplankton during an experimental bloom in marine microcosms
Authors: De Madariaga I. , Fernandez E.
Published: May 2009

Water samples, taken from station El in the English Channel, were incubated in 12–1 bottles and monitored for nine days. The distribution pattern of photosynthetically incorporated 14C was followed in three different size-fractions (0·2–2 μm, 2–10 μm and >10 μm) during the development of a bloom.

A rapid increase in chlorophyll was observed just after enclosure, the highest values being reached by day 5, when a mixed community of diatoms and small flagellates formed the bulk of phytoplankton biomass. As the bloom developed, nutrients were depleted and, consequently, a decay of the phytoplankton populations occurred. Growth rates, estimated as chlorophyll-specific production rate, were higher for the largest size-fraction (0·53 d−1) than for the intermediate and smallest ones (0·32 d−1 for both).

Throughout the bloom, the proportions of 14C incorporated into protein and low molecular weight metabolites (LMWM) were small, whereas the synthesis of storage products appeared to be enhanced. Carbon fixed into protein was higher during the exponential growth phase in all size-fractions, and incorporation into LMWM increased sharply when the bloom declined. Storage product synthesis varied between size-fractions.

A close relationship was observed between growth rates, estimated as chlorophyll-specific production rate, and the protein/metabolite synthesis ratio (r2=0·90; n=24). These results suggest that, within the range of environmental variation we studied, this ratio would be a good estimator of growth rate for field studies.
Doliolids in the German bight in 1989: Evidence for exceptional inflow into the North Sea
Authors: Lindley J.A. , Roskell J. , Warner A.J. , Halliday N.C. , Hunt H.G. , John A.W.G. , Jonas T.D.
Published: May 2009

Doliolids were found in samples taken with a Continuous Plankton Recorder (CPR) in October 1989 between 55°14'N 03°32'E and 55°20'N 06°13'E during a tow between Newcastle and Esbjerg. Densities were estimated at >100 m−3 for about 112 km of tow. A sub-sample of specimens in sufficiently good condition to be reliably identified were referred to Doliolum nationalis Borgert. Substantial numbers of doliolids were found on a CPR tow between Harwich and Gothenburg which passed through the same area in that month and specimens were found nearer to the Danish coast in November and south-west of Helgoland in December. The distribution of doliolids in CPR samples taken in the North Sea in the last three months of 1989 is shown in Figure 1.
Ultrastructure of the heart and excretory system ofMytilus edulis(L.)
Authors: Pirie Brian J. S. , George Stephen G.
Published: May 2009

The morphology and ultrastructure of the heart and excretory system of the marine lamellibranch bivalve mollusc,Mytilus edulis(L.) are described. This paper supports the view that ultrafiltration of the blood occurs in the pericardial cavity. The auricles, pericardial glands and afferent oblique veins contain podocytes which are usually ascribed to the specific function of ultrafiltration. These cells are absent in the ventricle. The pericardial cavity communicates with the exterior via a very short (ca.1–2 mm) renal tubule. The kidney comprises of a series of highly branched diverticula of this tubule and displays little or no structural differences throughout the organ. The kidney cells form a single layered columnar epithelium with a brush border, basal nuclei, infolded basal membranes and are characterized by the presence of many membrane-limited granules occupying as much as 20% of the cell volume. These granules and those of the podocytes are subsequently shed into the lumen of the kidney tubule and are excreted in the urine which is therefore largely paniculate.
Analysis of the associations of meiobenthic Copepoda of the Irish Sea
Authors: Moore Colin G.
Published: May 2009

The composition of subtidal meiobenthic associations off the Isle of Man is analysed, with particular reference to the harpacticoid copepods. By comparisons with surveys in other seas it is suggested that coherent associations of benthic copepods can be recognized in the sublittoral fringe area of tidal fine sand beaches and in offshore fine sand in Europe. The heterogeneity of offshore coarse deposits and muddy sands results in the inability to distinguish communities or isocommunities in these deposits. As muddy sand grades into mud some evidence is presented to suggest that, given similar temperature and salinity regimes, a consistent association of copepods may develop.
Some observations on concentrically structured, intracellular granules in the hepatopancreas of the shore crab Carcinus maenas (L.)
Authors: Hopkin S. P. , Nott J. A.
Published: May 2009

The R, F and B cells of the hepatopancreas of Carcinus maenas are derived from undifferentiated (E) cells at the distal end of the tubules. Observations with the scanning electron microscope on freeze fractured tubules show that (a) most of the concentrically structured granules are confined to the R cells with few in F or B cells, (b) within individual R cells, granules are of similar size, and (c) the further R cells are situated from the distal end of the tubule, the greater is the mean diameter of the granules that they contain.
The dispersal and dispersion of some epizoites of the hydroid Nemertesia antennina (L.)
Authors: Hughes R. G.
Published: May 2009

The distribution of 18 common epizoic species between clumps of Nemertesia antennina is examined with reference to their dispersal behaviour and, for selected epizoites, to the occurrence of other epizoic species. Dispersal of the tubicolous amphipods Ericthonius brasiliensis, Jassa falcata and Corophium sextoni and the caprellids Pseudoprotella phasma and Caprella linearis by a proportion of the adult animals, and by some animals after mating, was suggested. This behaviour may establish and perpetuate aggregations of these amphipods since brood-mates, and some of their descendants, remain on their natal hydroid clump. Five of the nine species considered that disperse as planktonic larvae have aggregated dispersions and for two of these species, Rissoa parva and Cingula semistriata, gregariousness of their larvae at settlement was considered an important influence on their distribution. Comparisons between the distributions of selected epizoic species suggest that in only a few cases, notably where branching bryozoans may give protection to potential prey species, is the distribution of one species influenced by the occurrence of another.
Bass populations and movements on the west coast of the U.K.
Authors: Kelley Donovan
Published: May 2009

A bass tagging project on the south coast of Anglesey, 1971–5, yielded 86 recoveries from 912 taggings. In addition to expected local movements a systematic pattern of seasonal migration was identified for adults. Fish present in summer moved to south Cornwall for the winter, returning in succeeding summers for spawning. Departure was normally before mid-October. Fish present after that had summered further north (reaching Furness in warm summers). These too moved south as winter advanced, though possibly not reaching Cornwall. A few solitary fish – unfit specimens or members of weak year-classes – appeared to remain through the winter. No evidence was found of movement to, or intermingling with stocks of, the Irish coast; nor, with one exception, the mainland coast of Europe. There was also no indication of movement eastward along the south coast: suggesting discrete populations there from those on the west coast.
Inhibition of carbon fixation as a function of zinc uptake in natural phytoplankton assemblages
Authors: Davies Anthony G. , Sleep Jillian A.
Published: May 2009

There is now a substantial body of evidence that the growth rates of phytoplankton in culture are more closely related to the cellular levels of the rate-limiting constituent, be it a nutrient, micronutrient or toxic metal, than to the concentrations in the supporting medium; nitrate, Caperon (1968); phosphate, Fuhs (1969); silicate, Paasche (1973); vitamin B12, Droop (1968); iron, Davies (1970); mercury, Davies (1974); cadmium, Davies (1978a). This has suggested the requirement for a technique which would allow the determination of comparable relationships for natural populations of phytoplankton - how, for instance, their carbon fixation rates depend upon the metal contents of the plant cells. Although the effects of metals upon carbon fixation in phytoplankton assemblages from several different sea areas have already been examined (Knauer & Martin, 1972; Patin et al. 1974; Zingmark & Miller, 1975; Ibragim & Patin, 1976) no data seem to have been obtained on the levels of the metals present in the phytoplankton at the time of the measurements.
Zinc - a major inorganic component of nereid polychaete jaws
Authors: Bryan G. W. , Gibbs P. E.
Published: May 2009

Analyses of the jaws of nereid polychaetes have shown zinc to be a major inorganic component amounting to between 0·5 and 2·4% of the dry weight and accounting for up to 40% of the total body burden of zinc. In Nereis diversicolor, zinc concentrations in the jaws are not related to those of the habitat sediments. A high zinc content appears to be a structural characteristic of the nereid jaw.
SOND Cruise 1965 Biological sampling methods and procedures
Authors: Foxton P.
Published: May 2009

Details are given of the nets used and the sampling procedures adopted to investigate patterns of vertical distribution in an oceanic pelagic fauna. Ancillary gear and laboratory methods are described. The paper concludes with a discussion of the limitations of the sampling.
Breeding of Pseudocalanus elongatusin the laboratory
Authors: Katona S. K. , Moodie C. F.
Published: May 2009

Pseudocalanus elongatus(Boeck) from Plymouth Station Ex was kept in reproducing culture for 6 months and approximately four generations. Cultured adult females were at least as large as wild females of the same species which have
matured at a comparable temperature (15 °C) in nature. At 15 °C hatching time was 2—3 days, time to first copepodite was 18—20 days, and the time from egg to development of an egg-carrying female averaged 37 days.
Fast pressure pulses and communication between fish
Authors: Gray J. A. B. , Denton E. J.
Published: May 2009

Experiments on herring(Clupea harengusL.), sprat(Sprattus sprattus(L.)) and whiting(Merlangius merlangus(L.)) showed that when these fish make rapid swimming movements, such movements are preceded by fast pressure pulses in the surrounding sea water. Thefirst (a) phases of these pulses had durations of from 1–5 to 3–5 ms. The pulses could be excited in free-swimming fish by both visual and auditory stimuli and the latencies to the latter ranged from 5 to 8–5 ms. Identical pulses could be elicited by giving electrical stimuli to anaesthetized fish; these pulses had latencies from 34 to 7 ms.

The pressure fields around the fish were measured on suspended anaesthetized fish stimulated electrically. At any instant the fields of the fast pulses produced by whiting had the same polarity at all positions round the fish and pressure decayed inversely with the 1–5 powerof distance. Theaphase of the fast pulse was usually a decompression.

The fields around a stimulated herring were different. The pressures on both sides oppositethe centre of the fish were of one polarity while those around the head and the tail were of the opposite polarity, the pattern of pressure being symmetrical about the long axis of the fish.In our experiments the a phase opposite the centre of the fish was always a compression. The amplitudes of these pulses declined with distance by the power of 2–5. In all species in our experiments the fast pulses were followed by slower pulses associated with swimming movements; these slower pulses had opposite polarities at corresponding points on the two sides of the fish.
The development of bass, Dicentrarchus labrax, eggs in relation to temperature
Authors: Jennings S. , Pawson M. G.
Published: May 2009

Naturally spawned bass, Dicentrarchus labrax, eggs were incubated from fertilization at 15 temperatures from 6·8–20·6°C, and the developmental process was categorised into seven stages. Times from fertilization to the midpoints of each stage were calculated at each temperature. Knowledge of the developmental stage and incubation temperature was used to derive predictive relationships with which to age eggs. Minimum precision of age prediction was ±18 h. The first developmental stage was divided into six substages, and temperature-stage relationships derived to improve the precision of ageing to a minimum of ±1·75 h during early development. Bass eggs failed to hatch at temperatures below 9·7°C and above 16·8°C; this observation is discussed with reference to the developmental process.