bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of Egg Production in Mediterranean Populations of the Terebellid PolychaeteEupolymnia Nebulosa
Authors: Nozais Christian , Martin Daniel , Cha Jae-Hoon , Duchêne Jean Claude , Charles François , Grémare Antoine
Published: May 2009

The dynamics of egg production by a Mediterranean population of the terebellid polychaeteEupolymnia nebulosawas assessed both in the field and in the laboratory between 1992 and 1994. Our results confirm the occurrence of several peaks of jelly mass production at the population level. They show that such peaks result from the production of several broods per individual female (the number of produced broods increasing with female size). Jelly masses produced at the end of the breeding season tend to be smaller and to contain fewer eggs than those produced at the beginning of the breeding season. Worms produced significantly larger jelly masses in 1994 than in 1993 and 1992, without noticeable change in corresponding fecundities. The computation of temporal changes in eggs produced per unit of surface area in the cove of Paulilles shows that most of the eggs are produced during the first two peaks of jelly mass production. These results are discussed relative to the different hypotheses invoked to account for the occurrence of several spawnings in Mediterranean populations of E.nebulosa. It is concluded that no single explanation, such as the allometry constraint hypothesis or heterogeneity in oogenesis rates, can be retained.
Water Pumping in the Penduculate Barnacle Conchoderma Auritum
Authors: Achituv Y. , Yamaguchi T.
Published: May 2009

The cirral activity of the penduculate barnacle, Conchoderma auritum, was studied in a flow tank. The barnacles were exposed to different experimental water velocities and the response of the barnacles was recorded using a video system. In still and slow-moving water the barnacles show rhythmic cirral activity, the cirri extend and then withdraw into the mantle cavity. When water flow is accelerated the barnacles switch from rhythmic cirral activity to prolonged cirral extension, in which the cirri are extended in the water flow, facing the current. The water velocity at which barnacles switch from rhythmic activity to cirral extension depends on the size of the animal. During the rhythmic activity of Conchoderma water is pumped into the mantle through the ears. The prosoma serves as a piston which inhales the water into the capitulum and then ejects it at the apical end of the capitulum opening. This finding contradicts the generally accepted notion that the function of the ears of C. auritum is water ejection.
Redescription of The Southern Dumpling SquidEuprymna Tasmanicaand A Revision of The GenusEuprymna(Cephalopoda: Sepiolidae)
Authors: Norman M.D. , Lu C.C.
Published: May 2009

Recent attention to members of the sepiolid squid genusEuprymnaand symbiotic associations with luminescent bacteria (Vibrio fischeristrains) has prompted a review of this poorly-resolved group of squids. Twelve nominal species have been placed in this genus of which the majority are ill-defined, known only from their original descriptions and separated on the basis of inadequate characters. As a first step in resolving this group, a temperate Australian species, the Southern dumpling squid,Euprymna tasmanica, is here redescribed in detail. As the genusEuprymnacurrently stands, most members are only distinguished on the number and position of enlarged suckers in mature males. No diagnostic characters are available to identify females. All nominal species placed in this genus are reviewed and a key to proposed valid species is presented. Six species are considered here to be valid:Euprymna berryi, E. hoylei, E. morsei, E. scolopes, E. tasmanicaand an undescribed species treated here asEuprymnasp. 1.Euprymna similisis a synonym ofE. morseiof Japan. Due to inadequate original descriptions, and lost or poor type material, two species are considered here to benomen dubia(E. schneehageniandE. pusilla), while the taxonomic status of four additional species remain unresolved (E. albatrossae, E. bursa, E. phenaxandE. stenodactyla).
Genetic Divergence Between South AfricanHelcionSpecies and North-East AtlanticH. Pellucidum(Mollusca: Patellogastropoda)
Authors: Weber L.I. , Gray D.R. , Hodgson A.N. , Hawkins S.J.
Published: May 2009

Allozyme electrophoresis was used to estimate the genetic divergence between three species of South AfricanHelcionand the north-east AtlanticH. pellucidum(Patellidae). At a finer level the genetic relationships among South AfricanHelcionwere explored. Twenty-one loci were resolved for all the species. High values of expected heterozygosities (0·202–0·341) were found for the genus. Phenetic analysis (UPGMA (unweighted pair-group method with artihmetic averaging) and Distance Wagner Procedure) and cladistic parsimony methods (alleles as binary characters and loci as multistate unordered characters) agreed in showing the same topology for the tree which represents the genetic relationships amongHelcionspecies. The north-east AtlanticH. pellucidumwas the most divergent species showing high values of Nei's genetic distances (1·423–1·654) with its South African congeners. In the literature such values of genetic divergence have been associated with non-congeneric species. The degree of genetic divergence (0·351–0·615) found within the South African branch was characteristic for congeneric species. The results of this study supported the monophyletic condition of this branch, and showedH. pectunculusandH. pruinosusto be more closely related to each other than toH. dunkeri. Nevertheless, the monophyly of the genusHelcionis uncertain and therefore its taxonomic status was questioned. A possible independent origin for northern and southern hemisphere species ofHelcionis considered.
The Ligament of Mya Arenaria (Myoidea) Revisited
Authors: Checa Antonio G. , Cadée Gerhard C.
Published: May 2009

The ligament of the bivalve Mya arenaria was previously described as being composed of two layers: a fibrous and a lamellar one, the fibrous layer being more extensive. Other features described, such as the three-dimensional extent of the layers and their mode of attachment to the chondrophores, have been found to be inaccurate to a certain extent. The ligament is therefore redescribed here. It is conical in appearance and attached to the left chondrophore only at its margin, its interior being occupied by an epithelium, which is an extension of the mantle isthmus. The lamellar layer is a pyramidal body which merges into and constitutes the posterior extension of the fibrous layer. The whole structure is internal and may rotate around the dorsoventral axis, thus being suited to allow rocking of the valves. This kind of movement is used when Mya contracts the anterior adductor muscle to eject water from the mantle cavity during burrowing. In this respect the ligament is unique among those known in bivalves.
Is a mollusc an evolved bent metatrochophore? A histochemical investigation of neurogenesis in Mytilus (Mollusca: Bivalvia)
Authors: Raineri Margherita
Published: May 2009

Acetylcholinesterase (AChE) activity, a marker of neural differentiation, was histo-chemically localized in embryos and larvae of Mytilus galloprovincialis Lamarck and M. edulis L. (Mollusca: Bivalvia). The results show that: (1) the first AChE-active cells develop as two bilaterally symmetrical, postero-dorsal pioneer sensory neurons and their supporting superficial cells; (2) the pathways of their pioneering longitudinal axons are the same as those of two bilaterally symmetrical nerve cords which differentiate later in a postero-anterior direction; (3) in the conchostoma larva the posterior neurons and their associated superficial AChE-active cells give rise to two ciliary sensory-like organs which are the earliest rudiments of pedal ganglia and primary byssus glands; (4) three pairs of posttrochal gangliar rudiments, most probably visceral, parietal and pleural ganglia, develop on the same longitudinal nerve cords in the trochophore larva; (5) starting from the veliger stage, the presumptive foot rotates on the ventral side and migrates forwards, so that this gangliar chain is bent and the viscero-parietal ganglia become localized dorso-posteriorly to the pedal ganglia; (6) the cerebral ganglia differentiate together with the apical organ and the nerve network of the velum after the first pedal nerve rudiments have been detected.
Diet of ballan wrasse, Labrus bergylta, and some comparisons with the diet of corkwing wrasse, Crenilabrus melops
Authors: Deady Sandra , Fives Julie M.
Published: May 2009

The gut contents of 99 ballan wrasse (Labrus bergylta: Teleostei; Labridae) sampled between April and July in Galway Bay, Ireland and 95 ballan wrasse sampled between April and June in Dinard, Brittany, France were examined. Decapods and bivalves were the major prey categories in both areas, algae and gastropods were also frequently eaten but in much smaller amounts. The volume of the major food categories did not vary significantly with fish length. However, fish longer than 20 cm did consume greater volumes of bivalves than smaller fish. An increase in dietary diversity during the breeding season was observed. Ballan and corkwing (Crenilabrus melops) exploited many of the same food categories but with different emphases. Bivalves, which were major prey of corkwing, were also very important to the ballan captured simultaneously at the same site.
A Replica Method for the Study of Marine Biofilms
Authors: Marrs S. J. , Thomason J. C. , Cowling M. J. , Hodgkiess T.
Published: May 2009

A replica method involving the use of a polyvinylsiloxane impression material with a resin cast, particularly suitable in the study of marine biofilms, is described. The technique has advantages over other methods in that it is quick, non-toxic, non-destructive and inexpensive. Replicas of critical-point dried eggcases of the dogfishScyliorhinus canicula(L.) (Elasmobranchii: Squaliformes) showed the replica to be true down to the size of bacteria. It was also possible to replicate larger areas such as patches of living barnacles on an intertidal rock.

The study of marine biofilms often involves the use of destructive techniques such as conventional scanning electron microscopy (SEM), histology andin vacuospectroscopic methods (Baier & Meyer, 1986), so a single surface may not be examined repeatedly. Alternatively, the surface of interest may not be amenable to examination by standard techniques due to, for example, large size or incompatibility of the material of interest. In materials science the use of replica techniques to overcome such problems have been common (Goodhew, 1973), though techniques commonly involve the use of solvents (Loh, 1989) or silicone elastomers that may have a curing period of several hours (Gordon, 1984) and are consequently unsuitable for the study of biofilms. Scott (1982) reviewed the use of dental impression materials for field use in metallurgy and in recent years, dental impression materials have been used in the study of plant morphology (Green & Linstead, 1990). In this paper we consider the use of a hydrophilic polyvinylsiloxane impression material in the study of both microscopic and macroscopic marine biofilms.
The Measurement of Surface Energy by Video Analysis of Captive-Bubble Contact-Angles
Authors: Thomas Jeremy C. , Davenport John
Published: May 2009

Surface energy has been demonstrated to have a significant effect upon the settlement and growth of many marine organisms. However, the measurement of surface energy has either been too expensive for most marine laboratories to consider its use, or the methods used have relied upon classical contact-angle theory. Modern contact-angle theory and a video-based technique using captive bubbles are described. The technique is non-destructive, inexpensive, rapid and accurate enough to compare living and man-made surfaces. A precision of ~5° has been achieved and rapidly-changing angles can be quantified. Data for PTFE sheet, Parafilm, acetate sheet, Geltek gel, sea-water-conditioned slate, Porphyra umbilicalis (L.) Agardh, Ciona intestinalis (L.), and Cyanea capillata (L.) are presented. The contact angles for the living surfaces are smaller (31–44°) than for all the non-living surfaces (73–112°), suggesting overall higher surface energies for the biological materials studied.
Effect of low temperature on oxygen uptake and haemolymph ions in the sandhopper Talitrus saltator (Crustacea: Amphipoda)
Authors: Spicer John I. , Morritt David , Taylor Alan C.
Published: May 2009

The common sandhopper of European shores, Talitrus saltator (Montagu, 1808) (Crustacea: Amphipoda) remains inactive in high shore burrows for much of the winter in more northern latitudes. In the laboratory exposure to low temperature (2 or 3°C) was accompanied by the onset of inactivity, a precipitous decrease in oxygen uptake and a marked increase in the concentrations of the major ions in the haemolymph. The increase in the concentration of Mg2+ in the haemolymph was particularly pronounced. The possibility that Mg2+ ions are implicated in bringing about a reduction in activity and oxygen uptake is discussed.
Reproductive biology of Todaropsis eblanae (Cephalopoda: Ommastrephidae) in Scottish waters
Authors: Hastie L.C. , Joy J.B. , Pierce G.J. , Yau C.
Published: May 2009

During a study based on catches taken in the northern North Sea by selected Scottish fishing boats during 1985–1992, large numbers of the normally rare short-fin squid, Todaropsis eblanae (Cephalopoda: Ommastrephidae), were recorded in 1987 and 1990. Our findings, supported by data obtained from plankton/young fish surveys in 1988 and 1989, suggest that in northern waters Todaropsis eblanae generally mates and spawns during late summer and early autumn (June-November). Successful hatching events appear to occur during October-March, producing juvenile (stage I) squid in the early part of the year (January-June). Estimations of maximum male reproductive output and female fecundity were up to 130 spermatophores and ~28,000 eggs per individual, respectively.
Reproduction inBathyplotes natans(Holothurioidea: Synallactidae) from bathyal depths in the north-east and western Atlantic
Authors: Tyler P.A. , Eckelbarger K. , Billett D.S.M.
Published: May 2009

The gross morphology, histology, ultrastructure and periodicity of gonad development of the bathyal aspidochirote holothurianBathyplotes natansis described and compared with the ‘tubule recruitment model’ proposed for aspidochirote holothurians. AsB. natansgrows, additional gonad tubules develop at the anterior end of the gonad basis. Oocyte development in these tubules is non-seasonal and the population of oocytes consists of both pre-vitellogenic and vitellogenic oocytes as well as some large oocytes undergoing phagocytic breakdown. Vitellogenesis is similar to that described previously for holothurians, although the follicular inner epithelium cells surrounding the developing oocytes are different from those previously reported. In males the unique acrosomal complex consists of three depressions with the acrosome lying in the central depression. The tubule recruitment model of Smiley does not apply toB. natans. We do not feel this model has widespread applicability in the Aspidochirotida or the Holothurioidea in general.
New distribution and host record for the starfish parasite Dendrogaster (Crustacea: Ascothoracida)
Authors: Hamel Jean-François , Mercier Annie
Published: May 2009

This work presents the description of an intracoelomic parasite of the genus Dendrogaster (Crustacea: Ascothoracida), the largest ever reported, collected for the first time from the starfish Hippasteria phrygiana in the deep waters of the St Lawrence Estuary (eastern Canada). The parasite bears a close resemblance to only one previously described species, D. arbusculus from the west American coast, suggesting a bicoastal and possibly circumpolar distribution. Female growth is concurrent with embryo development and the parasite may have a negative impact on host starfish densities through gonad atrophy. This research also demystifies the old and persistent description of a supposed parasite in H. phrygiana 70 years ago, Laocoön paradoxus, and finally concludes that this parasite never existed and in fact represents the water vascular system found in all starfish.
Nanoplankton and protozoan microzooplankton during the JGOFS North Atlantic Bloom Experiment: 1989 and 1990
Authors: Stoecker Diane K. , Sieracki Michael E. , Verity Peter G. , Michaels Ann E. , Haugen Elin , Burkill Peter H. , Edwards Elaine S.
Published: May 2009

Complex mesoscale eddy interactions are characteristic of the North Atlantic, resulting in a mosaic of water masses with different physical, chemical and biological properties. Observations of protist assemblages during spring 1989 and 1990 in the vicinity of 47°N 18°W indicate that timing, composition, and further development of the spring bloom community are highly variable between years. During 1989 a microbial community, dominated by small photosynthetic nanoplankton and protist grazers, was observed after the main diatom bloom in the transition zone between two cyclonic eddies. This community was characterized by a high ratio of ‘protozoan’ to ‘phytoplankton’ carbon, and dominance of the microzooplankton by mixotrophic ciliates. A nanodiatom/prymnesiophyte bloom was observed to replace the typical ‘microdiatom’ bloom in a front between a cyclonic and anticyclonic eddy during 1990. After the demise of the diatoms, high standing stocks of nanophytoplankton persisted until early June. In this post-diatom-bloom period, the ‘protozoan’ biomass was lower and the ‘nanophytoplankton’ stocks higher than in 1989. Very high stocks of heterotrophic nanodinoflagellates were observed in 1990. The factors responsible for the development of these quite different microbial food-webs in two consecutive years and the consequences thereof for ecosystem function remain to be more fully explored.
Differences in morphology, survival and size between self- and cross-fertilized larvae of Mytilus galloprovincialis
Authors: Beaumont A.R. , Matin-Abdul A.K.M.
Published: May 2009

The serendipitous detection of a rare hermaphrodite individual of Mytilus galloprovincialis during the process of spawning in the laboratory enabled self- and cross-fertilization to be achieved. Self-fertilized larvae exhibited significantly higher percentages of morphological abnormality at 3 d, lower survival at 9 d and decreased size at 31 d of age compared with cross-fertilized larvae. These results are discussed in the light of equivocal evidence for inbreeding depression in larvae derived from self-fertilization, full-sib matings and gynogenesis in other bivalves.
Identification of eggs of hake, Merluccius merluccius
Authors: Coombs S.H.
Published: May 2009

A practical method for separating eggs of hake, Merluccius merluccius (Pisces: Merlucciidae), from samples of mixed plankton is described.
Arsenic compounds in tissues of the leatherback turtle, Dermochelys coriacea
Authors: Edmonds J.S. , Shibata Y. , Prince R.I.T. , Francesconi K.A. , Morita M.
Published: May 2009

Examination of extracts of tissues of a leatherback turtle, Dermochelys coriacea (L.) (Reptilia: Dermochelyidae) by high-performance liquid chromatography inductively coupled plasma-mass spectrometry has demonstrated the presence of arsenobetaine, arsenocholine and inorganic arsenate in heart muscle and liver, and arsenobetaine and inorganic arsenate in pectoral muscle. Although arsenobetaine was the major form in all tissues, inorganic arsenate and arsenocholine accounted for 50% and 15% respectively of arsenic in aqueous extracts of the liver.
Dynamics of Colonization by the Beadlet Anemone,Actinia Equina
Authors: Brace R. C. , Quicke D. L. J.
Published: May 2009

Colonization of the littoral zone presents many problems to both sessile and relatively sessile invertebrates. These may be especially acute for inhabitants of the upper reaches of this zone, since suitable niches are usually sparsely distributed there, and are often ephemeral in nature. Consequently, both intraand inter-specific competition for space is likely to be particularly intense.

The widely distributed and abundant, beadlet anemone,Actinia equinaL., in common with a number of other littoral anthozoans, is apparently capable of both asexual (apomixis or somatic embryogenesis; Polteva, 1963; Gashout & Ormond, 1979; Orr, Thorpe & Carter, 1982) and sexual (Carter & Thorp, 1979) reproduction. The former results in the production of young, which are brooded within the coelenteron and which appear most suited to local dispersal, whilst the latter, if it occurs, is assumed to involve either ovipary or larvipary followed by a planktonic phase. Study of this species therefore affords an opportunity to investigate the dynamics of colonization and dispersal in an heterogeneous environment, in relation to flexibility in reproductive tactics.
Seasonal Changes in Dispersion Within an Aggregation of the Anemone, Actinia Equina, With a Reappraisal of the Role of Intraspecific Aggression
Authors: Brace R. C. , Quicke D. L. J.
Published: May 2009

Although intraspecific aggression in the anemone, Actinia equina L. has been behaviourally well characterized in laboratory-based studies (Bonnin, 1964; Brace & Pavey, 1978; Brace, Pavey & Quicke, 1979), both its incidence and functional role on the shore have remained obscure. Since A. equina broods young, which are produced asexually (Carter & Thorp, 1979; Gashout & Ormond, 1979; Orr, Thorpe & Carter, 1982) and which appear best suited to local dispersal, we have previously postulated that aggression is likely to be primarily directed towards maintaining ‘territorial’ space for settling syngeneic offspring (Quicke & Brace, 1983; Brace & Quicke, 1985). As such, this postulated role is functionally analogous to that provided by aggression in the clonally reproducing anemone, Anthopleura elegantissima Brandt, in which it serves to maintain the integrity of clonal boundaries (Francis, 1973, 1976), thereby presumably also facilitating the competitive expansion of those boundaries. Work by Ayre (1983) on the Australian anemone, Actinia tenebrosa Farquhar appears to support this contention, for both local settlement and genotypic clustering were detected within aggregations.
The Amphipod Sibling Pair Leucothoe Lilljeborgi and L. Incisa in British and Irish Waters
Authors: Myers A. A. , Costello M. J.
Published: May 2009

Krapp-Schickel (1975) described three closely related species of Leucothoe Leach, which together make up a Leucothoe lilljeborgi species complex (L. lilljeborgi Boeck, L. incisa Robertson, L. occulta Krapp-Schickel) in European waters. Of these, the two species L. lilljeborgi and L. incisa have caused considerable problems to taxonomists. As pointed out by Lincoln (1979), ‘There has been a lot of confusion over the identification of lilljeborgi and incisa and it would be advisable to treat earlier records with caution.’ Despite Lincoln's (1979) work, however, the problem persists, several workers (P. G. Moore & J. M. C. Holmes, personal communications) having noted forms apparently intermediate between these two species.

In order to clarify the situation, we have examined material from localities in Ireland and Britain. It is clear that the existence of apparent ‘intermediates’ is due to unfortunate choice of key characters by Lincoln, one of which requires phase contrast microscopy for correct determination. In his key to species of Leucothoe (1979, p. 172) he separates the two species by the anterodistal margin of coxa 4 being either angular (lilljeborgi) or rounded (incisa) and by the inner margin of the gnathopod 1 carpal process being either toothed (incisa) or smooth (lilljeborgi) (although in the description of L. lilljeborgi (p. 176) this process is described as weakly crenulate). Thus specimens with toothed gnathopod 1 carpal process and angular coxa 4 anterodistal margin, appear to be intermediate. It is apparent from our studies, that both L. lilljeborgi and L. incisa have a toothed gnathopod 1 carpal process, but that the structure of the teeth is quite different as revealed by phase contrast microscopy.
Synoptic Surveys of the Western English Channel. The Relationships Between Plankton and Hydrography
Authors: Robinson G. A. , Aiken J. , Hunt H. G.
Published: May 2009

Variability in the distribution and abundance of the plankton of the western English Channel has been investigated in relation to the hydrography of the region by surveys using the Continuous Plankton Recorder (CPR) (Hardy, 1939) and the Undulating Oceanographic Recorder (UOR) (Aiken, 1981a). Previous surveys in the western English Channel have been restricted in area or in time. Harvey et al. (1935), Holligan & Harbour (1977) and Maddock, Boalch & Harbour (1981) have studied the seasonal succession of the plankton at point stations near Plymouth, with analysis of patterns of seasonal succession and phyto-zooplankton relationships; Boalch, Harbour & Butler (1978) measured primary production at three stations across the western English Channel over a period of eleven years (1964–74); Pingree et al. (1976) have shown that the development of populations of phytoplankton are influenced by the establishment and development of the seasonal thermocline and also frontal regions, both of which are determined largely by tidal streaming.
Pyrolysis Mass Spectrometry as a Technique For Studying Inter- and Intraspecific Relationships in the GenusFucus
Authors: Hardy F.G. , Scott G.W. , Sisson P.R. , Lightfoot N.F. , Mulyadi
Published: May 2009

Pyrolysis mass spectrometry (PyMS) was used to investigate the relationships of members of the genusFucus(F.spiralis, F. veskulosus, F. ceranoidesand F.serratus), and betweenF. spiralisand F.spiralisformananus. Fucus spiralisand F.spiralisformananuswere not separable by PyMS and are thus a single species.Fucus spiralis, F. veskulosus, F. ceranoidesand F.serratuswere separable and their status as species confirmed. The pattern of relatedness between these species suggests a re-evaluation of their evolutionary history in that F.spiralis, F. vesiculosusand F.serratusare more similar to one another than to F.ceranoides.Pyrolysis mass spectrometry was also used to investigate the position of plants identified as putative hybrids between F.spiralisand F.vesiculosus.These plants were found to be intermediate between the two species thus confirming morphological evidence.
Spatial Variability in the Distribution of Sponges and Cnidarians in a Sublittoral Marine Cave with Sulphur-Water Springs
Authors: Benedetti-Cecchi L. , Airoldi L. , Abbiati M. , Cinelli F.
Published: May 2009

The distribution of sponges (Aplysilla sulfurea, Geodia cydonium and Petrosia ficiformis) and cnidarians (Astroides calycularis, Caryophyllia inornata and Leptosammia pruvoti) was investigated in a sublittoral cave with sulphur water springs from May 1993 to February 1994 at Capo Palinuro, on the south-western coast of Italy. Multi-factorial sampling designs were used to address: (1) the distribution and abundance of sponges and cnidarians on the vault and the sides of the cave at different distances from the entrance; (2) the distribution of cnidarians on the vault of the cave with respect to the type of substratum (sponges vs others) and distance from the entrance; and (3) whether abundances were correlated with the distance from the sulphur boundary and how this relationships changed moving from the outer to the inner part of the cave. All the sources of variation included in the study affected to some degree the distribution of organisms but patterns were not consistent among species. The abundance of A. calycularis decreased proceeding from the outer to the inner part of the cave, while the reverse was observed for L. pruvoti. Differences also occurred between the vault and the sides, A. calycularis and G. cydonium being completely absent on the vertical walls. Both A. calycularis and L. pruvoti were less abundant on sponges than on other types of substratum, but patterns changed in relation to the distance from the entrance. The abundance of L. pruvoti decreased close to the sulphur boundary, while the percentage cover of A. calycularis increased, but only at outer positions. Strong variability also occurred at the spatial scale of a few metres (between replicated areas) often overriding other patterns of distribution. Results have been discussed in terms of variability in the physico-chemical environment and in the outcome of interspecific interactions.
Ribosomal (rDNA) Variation in a Deep Sea Hydrothermal Vent Polychaete,Alvinella Pompejana, From 13°N on the East Pacific Rise
Authors: Jollivet D. , Dixon L.R.J. , Desbruyeres D. , Dixon D.R.
Published: May 2009

The rDNA repeat-unit of the vent polychaeteAlvinella pompejanawas investigated using restriction analysis. Mapping revealed evidence of rDNA polymorphism within and between individuals which was due to individual restriction site variation and sequence rearrangements involving spacer regions. The size of the repeat unit was 10.5 kb with virtually no evidence of length variation. Sequence inversions indicated the presence of two spatially-distinct subfamilies of repeats, probably on different chromosome pairs. Animals from contrasting vent habitats with respect to age and chemical emissions (young vs old chimneys and white vs black smokers) from within the 13°N/EPR (East Pacific Rise) vent sector were analysed for evidence of population differentiation. Based on individual restriction site variation, averageFSTestimates across neighbouring populations were in the region of ~0.05 and differed significantly from zero. This level of genetic differentiation is comparable to values reported previously for allozymes. Spatial and temporal allelic frequency variances estimated from pairwise combinations (i.e.s2Sands2T) strongly suggested that differences in allelic frequency were the result of repeated extinction/recolonization events associated with the vent instability. Estimates of the effective population size derived from standardized temporal allelic frequency variancesFkswere very low compared to actual population size indicating great temporal fluctuations in the former. Theoretically, such an effective population size is not sufficient to maintain the observed level of polymorphism within the 13N/EPR vent sector. Results are therefore consistent with a ‘propagule’ colonization-type model in which extinction/recolonization rates are high. InAlvinella, planktonic larval dispersal appears sufficient to overcome any genetic differentiation resulting from drift, but these findings also indicate that propagules may only be capable of dispersing a few tens of kilometres per generation.
A New Genus and 12 New Species of Eunicidae (Polychaeta) from the Caribbean Sea
Authors: Parra-Carrera Luis F. , Salazar-Vallejo Sergio I.
Published: May 2009

A new genus is established in Eunicidae:Fauchaldiusgen. nov., a symbiont of hexactinellid sponges that has only subacicular hooks, withF. cyrtaulonisp. nov. as its type species. Nine new species are described inEunice: E. hernandezisp. nov.,E. ibarzabalaesp. nov.,E. mikelisp. nov. andE. nonatoisp. nov. all belonging to the fuscusbidentate group;E. edwinlinkaesp. nov.,E. hartmanaesp. nov.,E. lanaisp. nov., andE. miuraisp. nov. all belonging to the flavus-tridentate group; andE. donathisp. nov. that belongs to the fuscus-unidentate group. Further, two new species are described inMarphysa: M. angelisp. nov. that is grouped with species having only composite falcigers, andM. orensanzisp. nov. that belongs to the group with composite falcigers and composite spinigers. A key to identify genera in Eunicidae is included. A key to identify species ofEuniceis appended.
Allozyme Similarity in Two Morphologically Distinguishable Populations ofParacentrotus Lividus(Echinodermata) From Distinct Areas of the Mediterranean Coast
Authors: Arculeo M. , Lo Brutto S. , Pancucci M.P. , Cammarata M. , Parrinello N.
Published: May 2009

Allozymes ofParacentrotus lividusfrom Palermo Gulf in the northern Sicilian coast (Italy) and from a small body-size population in the western Greek coast (Ionian Sea) were investigated by PAGE. Five of the twenty examined loci were polymorphic(AAT*, ADH*, ME*, PGI*andPGM*)over each population with a polymorphism value of 0–25. Average heterozygosity was equal to 0081 in the Sicilian sample and 0084 in the Greek. Deviations from Hardy-Weinberg equilibrium were significant inME*andPGI*loci (as calculated byy).Nei's (1978) genetic distance (D=0–0025) index described a close identity between the two samples. FSTvalue of polymorphic loci ranged from 0001 to 0029, its mean value (0–008) resulting low and appearing to be discriminate between the samples with a significant difference (P<0–05). The number of migrants per generation was equal to 31.
Life History Traits of Hoplostethus Mediterraneus (Pisces: Beryciformes) From the North-Western Ionian Sea (Mediterranean Sea)
Authors: D'onghia G. , Tursi A. , Marano C.A. , Basanisi M.
Published: May 2009

The fish Hoplostethus mediterraneus is a bycatch of the deep-water trawling in the north-western Ionian Sea. Data on its life history traits were collected during twelve trawl surveys carried out at two month intervals, between August 1993 and July 1995.

A vertical distribution according to size was observed for this species. The year's young were recruited mainly during the spring-summer period. Sex-ratio changed by size with females larger than males. Mature specimens were found mainly between May and November with a reproductive peak during late summer.

Seasonal growth was detected in the otoliths; the maximum ages of 11 and 10 y were observed in females and males respectively. Von Bertalanffy growth parameters for the whole population were: L3C=287–08 mm, k=0–127 y, to=-2–131. No significant differences were detected between the growth patterns of the sexes. Overall growth perfomance depicted through size-distribution analysis was not significantly different from that obtained by otolith reading.

Estimates of natural mortality rate for the whole population ranged from 0–14 to 0–20. Population structure, growth pattern, age at first maturity and low natural mortality rate indicate a life history mainly constituted by k-strategy characters and regulated by density-dependent mechanisms.
On the number of Patella species in south-west England
Authors: Gaffney Patrick M.
Published: May 2009

Limpet populations of the genus Patella from the south-west coast of England were examined by means of gel electrophoresis in order to settle debate on the specific status of the three Patella forms. Populations varied morphologically along an east-west gradient, from three distinct forms in the west to continuous intergradation in the east, in accord with earlier studies. Patella collected were divided into three groups on the basis of a complex of external features described by earlier workers, corresponding to the morphologically defined taxa P. vulgata Linn., 1758, P. aspera Röding, 1798, and P. depressa Pennant, 1777. These groups were electrophoretically distinct in five of seven enzyme systems examined, with no hybrids or intermediates. Incomplete speciation and hybridization can be ruled out as possible causes of the observed morphological variation.
Growth and reproductive rates of Littorina neritoides (L.) in North Wales
Authors: Hughes Roger N. , Roberts Derek J.
Published: May 2009

Growth rates in shell height on the shore and the number of eggs released in the laboratory during the spawning season were extremely variable among Littorina neritoides from a population on Anglesey, N. Wales. Much of this variability was attributed to the effects of unpredictable weather conditions on feeding activity. Thirtyper cent of the individually tagged snails in the population did not grow during 1976–8. Growth increments of the remaining snails were used to estimate the growth parameter, k, of the von Bertalanffy growth equation, and the asymptotic size, h∞, used in the equation was estimated to be 7·5 mm, corresponding to the largest individual found in the population. The von Bertalanffy equation was then used to construct a growth schedule for L. neritoides from post-settlement to the attainment of the asymptotic size. From this schedule, snails were expected to take at least 9 months to grow to a shell height of 2 mm and at least 5 years to grow to 7 mm. This growth schedule agrees closely with growth rates observed by Lysaght (1941) in a population at Plymouth, but predicts much lower growth rates than those estimated by Daguzan (1976) for a population in Brittany. Eggs were released from March to June in 1977 and from January to June in 1978. The extreme individual variability in egg production largely obscured the underlying relationship between fecundity and body size. The maximum observed fecundity was for a 71 mm snail which released a total of 3866 eggs during the 1978 spawning season. The average fecundity was 22 eggs per day during the 1978 spawning season, or about 300 eggs per season.
The energetics of tube production by Mercierella enigmatica (Polychaeta: Serpulidae)
Authors: Dixon David R.
Published: May 2009

The production of tubes by the serpulid polychaete Mercierella enigmatica is compared with somatic growth and reproduction, and is shown to account for the greatest portion of production energy expenditure.

INTRODUCTION

The tube of a serpulid polychaete consists of two major fractions, a conspicuous calcareous component comprising small crystals of aragonite or calcite, and a more diffuse organic matrix (Hedley, 1956; Neff; 1971). The continuity of the organic matrix was demonstrated by Hedley (1956), who showed that careful decalcifkation failed to disturb the form of the tube of Pomatoceros triqueter (L.).

The serpulid Mercierella enigmatica Fauvel (Ficopomatus enigmaticus cf. ten Hove & Weerdenburg, 1978) secretes a hard, calcareous tube shortly after it settles from the plankton (Rullier, 1955; Vuillemin, 1965). Initially, tube growth is relatively fast, but as the tube increases in length so the rate of growth declines. However, the tube of the adult worm can be as much as 80 mm in length, or more than four times the length of its body.
Observations on a Gyrodinium aureolum (Dinophyta) bloom off the south coast of ireland
Authors: Pybus C.
Published: May 2009

Gyrodinium aureclum formed an extensive red tide off the south and south-west coasts of Ireland in 1978. Here are presented observations, made off Kinsale, about the biology of the bloom and the nutrient water chemistry associated with the bloom. Comparisons are made with other Gyrodinium red tides which have been recorded in the literature.
An account of the eggs and developmental stages of Montagu's blenny, Coryphoblennius galerita (L.), with notes on the reproductive behaviour of the adults
Authors: Fives Julie M.
Published: May 2009

Montagu's blenny, Coryphoblennius galerita was reared to late larval stage under laboratory conditions. The adult male guarded the eggs and aerated them with its tail during the incubation period. The larvae had a small amount of yolk on hatching and although they appeared to be feeding on the variety of food introduced, no food was observed in the gut. The gas bladder, observable above the gut in all larvae, was filled with gas only in the one specimen, killed at 45 mm T.l., which survived after the yolk was utilized, and in some 4 mm specimens taken from the plankton off Mweenish.

Descriptions are given of the larval stages and of juveniles taken from rock pools.
A correction to the Poole and Atkins Secchi disc/light-attenuation formula
Authors: Walker Terriss A.
Published: May 2009

Re-examination of the original and subsequent data from Secchi disc studies leads to a revised constant in the light attenuation formula applicable to general field-work.

In theory, the depth at which a Secchi disc disappears from an observer's sight, Ds, is inversely proportional to the sum of attenuation coefficients for diffuse and collimated photopic light (Tyler, 1968). By definition, photopic light is measured by a sensor with the same spectral response curve as the normal human eye. In practice, the usefulness of the theoretical equation is restricted. More commonly, a simple empirically derived formula is used to estimate the attenuation coefficient for diffuse downwelling light, k, directly from Ds. Poole & Atkins (1929), in their pioneering work on light penetration in the sea, derived the relationship k × Ds – 17 for water in the English Channel. This formula is used extensively by workers who are unable to measure k directly and it is given regularly in oceanography and marine biology texts. More recently, a number of investigators have proposed alternative equations relating k to Ds in different regional seas (Table 1). However, Idso & Gilbert (1974) have fitted data of some of these authors, together with measurements of their own, to the original Poole and Atkins formula with good correlation. They suggest that k × Ds = 1.7 is a universal approximation for all natural waters. In view of the continuing importance of the Secchi disc as a measure of underwater light for primary production calculations and other studies, a universal formula is certainly desirable. However, re-examination of the Poole & Atkins measurements has revealed an error in the method of calculation of k.
The component fatty acids of the lipids of some species of marine and freshwater molluscs
Authors: Gardner Doris , Riley J. P.
Published: May 2009

The component fatty-acid patterns of the triglycerides, phospholipids and, in some instances, sterol esters of a number of aquatic molluscs have been determined. The species examined include several of marine origin(Chlamys opercularis, Crepidula fornicata, Mytilus edulis, Neptunea antiqua, Patella vulgataandPecten maximus)and one of freshwater origin(Anodontasp.). The marine species contained considerable proportions of highly unsaturated acids of the C and C series (eg. 20:5 and 22:5) which are characteristic of the lipids of most aquatic plants and animals. In general, the relative percentages of 18:1,20:1 and 20:4 (5,8,11,14) were greater in the lipids of the marine gastro-pods than in those of the pelecypods. The differences between the fatty-acid distributions of theAnodontasp. and marine members of the pelecypoda are analogous to those existing between other freshwater and marine animals. Studies were made of the seasonal variations in the relative proportions and fatty-acid compositions of the triglycerides and phospholipids inP. vulgata.The relative proportions of 20:4 (5,8,11,14) and 20:5 in the triglycerides rose abruptly from minimum values in January to maximum values in March and thereafter declined slowly. These changes were mainly compensated by inverse variations in the proportions of saturated and oleic acids. In contrast to the triglycerides there appears to be no significant seasonal differences in the fatty acid patterns of the phospholipids.
On the organization of silvery layers in the skin of the Atlantic salmon(Salmo salar)during smoltification and on the regeneration of these layers underAbnormal lighting conditions
Authors: Denton E. J. , Saunders R. L.
Published: May 2009

The reflecting layers in the external surfaces of salmon were studied during smoltification by making direct observations on the reflecting structures. The relationships between the reflecting layers in the epithelium external to the scales, in the tissues of the scales, and in the skin internal to the scales are given. Some fish, including fish blinded by pseudobranchectomy were reared under very abnormal lighting conditions and the processes of silvering and regeneration of scales followed on them. It was found that the pattern of silvering in smoltification and regeneration was not at all affected by lighting and that, although regenerated scales can easily be distinguished in other ways from those they replace, the orientations and reflectivities of their plate-lets are, with occasional exceptions, almost indistinguishable from those they replace.
Osmotic properties of the epithelial layers covering scales of herring (Clupea harengus) and Atlantic salmon (Salmo salar)
Authors: Denton E. J. , Saunders R. L.
Published: May 2009

An account is given of the effects of changes of concentration of salts in the ambient medium on the colours reflected by the scales of herring and salmon. These lead to the conclusions (1) that in the herring in life the reflecting cells which lie under the scales and outside the scale pocket are in osmotic equilibrium with the external medium and not with the fish's body fluid (2) that the corresponding cells which lie inside the scale pocket of herring are always in equilibrium with these body fluids (3) that in the salmon all parts of the scale, including the parts outside the scale pocket, are in equilibrium with the internal body fluid and osmotically protected from the external medium.
The abundance and distribution of eggs and larvae of some teleost fishes off Plymouth in 1969 and 1970 I. Methods and hydrography
Authors: Southward A. J. , Demir Necla
Published: May 2009

An area in the English Channel of 20 × 40 nautical miles, centred on the Plymouth routine stations L, L and E, was sampled at almost monthly intervals from August 1969 to November 1970, using an improved version of the 1 m net towed at 4 knots on an oblique path. The area includes an inshore region where depths are about 20 fm (37 m) and salinities 35·0‰ or less, and an offshore region with depths over 40 fm (74 m), where salinities can exceed 35·3·. During the first year the offshore region was characterized by water of south-western origin, and temperatures were higher than in the following year when north-western plankton was more in evidence.
The breeding cycle and growth of open coast and estuarine populations ofLittorina littorea
Authors: Fish J. D.
Published: May 2009

The breeding cycle and growth of a population of Littorina littorea (L.)from an exposed rocky shore is compared with a population from a neighbouring sheltered estuarine habitat. The estuarine population matures earlier in the year, and maximum spawning activity is recorded in January compared with March on the open coast. This is considered to be the result of the higher nutritional status of the estuary. Egg capsules and veliger larvae have been found amongst the detritus on the estuary, and the establishment of an earlier settlement in this population is explained by concluding that a substantial proportion of the egg capsules do not leave the estuary, but undergo their full development in the moist detritus. At both localities individuals are sexually mature at a shell height of about 11–12 mm. Snails from the estuary reproduce for the first time during their second winter compared with the second or third winter for the open coast population.
An example of hybridization between Pagurus bernhardus and Pagurus pubescens [Crustacea:Anomura]
Authors: Jennings K. N.
Published: May 2009

Several examples of intermediates between the closely related hermit crabs Pagurus bernhardus (L.) and P. pubescens Krayer are reported. Selected critical characters were examined in the two species and the intermediates and the results accord with the belief that the latter are the result of hybridization. The implied closeness of the relationship between the two species agrees with the evidence presented by the larvae, as pointed out by MacDonald, Pike & Williamson (1957).