bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace Metal Accumulation in Marine Invertebrates: Marine Biology or Marine Chemistry?
Authors: Rainbow Philip S.
Published: May 2009

Trace metals are accumulated by marine invertebrates to body concentrations higher, in many cases orders of magnitude higher, than the concentrations in an equivalent weight of the surrounding sea-water (Eisler, 1981; Rainbow, 1990; Phillips & Rainbow, 1993). Specific details of trace metal accumulation processes vary within the same invertebrate species between metals, and for the same trace metal between invertebrates, often between closely related species (Rainbow, 1990, 1993). This short review attempts to highlight some of the comparative aspects of the processes involved that are expected and explicable in terms of the chemistry of the respective elements, and those where the physiology of the species involved intervenes to offset predictions from purely chemical principles. Although an appreciation of trace metal chemistry is crucial to an understanding of trace metal accumulation, idiosyncrasies in the biology of the invertebrate (at any taxon level) may intervene to bring about significant and unexpected comparative differences in metal accumulation patterns.
Observations on the Feeding Ecology of Estuarine Nematodes
Authors: Moens Tom , Vincx Magda
Published: May 2009

Observations on living estuarine nematodes show that previous feeding type classifications do not accurately represent the trophic structure of an intertidal mudflat in the Westerschelde Estuary (Netherlands). A new scheme with six major nematode feeding guilds is proposed: (1) microvores; (2) ciliate feeders; and (3) deposit feeders sensu stricto are all nematodes without a distinct buccal armature. In the first two groups bacteria and protozoa, respectively are the major particulate food sources, while other items are included in the diet of the third. The three other categories are recognized among the nematodes with a buccal armature: (4) epigrowth feeders; (5) facultative predators; and (6) predators. Diatoms and other microalgae are an important particulate food for many epigrowth feeders. The importance of bacteria as a food source for these nematodes remains poorly documented. A strictly or mainly predatory behaviour has been described for only few species from the study area. Several nematodes, however, are facultative predators. The predatory strategy of Calyptronema maxweberi, as described in this paper, suggests the use of a paralysing or lethal secretion in prey capture, which, to our knowledge, is the first report for aquatic nematodes. Furthermore, the importance of sources other than particulate food in free-living aquatic nematodes is stressed. Our observations show that many aquatic nematodes are in fact opportunistic feeders, which may change feeding strategies in response to available food.
Egg Production and Viability in Centropages Typicus: A Laboratory Study on the Effect of Food Concentration
Authors: Guerrero Francisco , Nival Suzanne , Nival Paul
Published: May 2009

The effect of food concentration on the reproductive success of the copepod Centropages typicus (Copepoda: Calanoida) was studied in the laboratory. Three different regimes of food were tested: absence of food, natural food conditions and a food media enriched with an algal culture. The results showed significant differences in egg production rate between regimes of food, but no significant differences in egg viability. A rapid response (24 h) in egg production rate to increment in the quantity of food was noted. Hatching success was not affected by food conditions prevailing during the incubations.
Cyst Membrane Protein Composition as a Discriminant Character in the GenusArtemia. (International Study onArtemiaLV)
Authors: Abatzopoulos T.J. , Triantaphyllidis G.V. , Beardmore J.A. , Sorgeloos P.
Published: May 2009

Isolated embryonic membranes (i.e. the outer cuticular membrane, the fibrous layer, the inner cuticular membrane and the hatching membrane) and homogenates of incubated, decapsulated cysts of 16 populations from fiveArtemiaspecies (Crustacea, Anostraca) were examined by sodium dodecyl-sulphate polyacrylamide gel electrophoresis. Characteristic differences in major polypeptides between 45 and 205 kD were seen. These differences might be used as markers for identification of differentArtemiaspecies. The validity of this approach in characterizingArtemiapopulations is discussed.
Modulations in Cell-Mediated Immunity of Mytilus Edulis Following the ‘Sea Empress’ Oil Spill
Authors: Dyrynda E.A. , Law R.J. , Dyrynda P.E.J. , Kelly C.A. , Pipe R.K. , Graham K.L. , Ratcliffe N.A.
Published: May 2009

The ‘Sea Empress’ oil tanker grounded outside Milford Haven (Wales, UK) in February 1996, spilling ~70,000 tonnes of crude oil and contaminating over 100 km of coastline, causing mass mortalities and standings of at least 11 mollusc species. Intensive field monitoring commenced after the spill, examining immunity and hydrocarbon levels in the mussel, Mytilus edulis (Mollusca: Bivalvia), a commercially-harvested species which can accumulate contaminants. Comparisons of mussels from oiled and reference sites revealed significant modulations in cell-mediated immunity. Elevations in blood cell (haemocyte) numbers and decreases in superoxide generation and phagocytosis were identified in contaminated animals. The immune response of contaminated mussels gradually improved and generally showed no significant differences compared with clean mussels after 11 weeks. By then, total hydrocarbon content in contaminated mussels had declined by 70–90%, while polycyclic aromatic hydrocarbon content had decreased by over 90%.
Nutritional value of dried algae diets for larvae of Manila clam(Tapes philippinarum)
Authors: Laing Ian , Child Anthony R. , Janke Achim
Published: May 2009

Spray-driedNannochlorissp. andTetraselmis suecicawere fed to larvae of the Manila clam(Tapes philippinarum).

These dried diets supported growth equal to, or greater than, their live algal counter-parts, but less than a control diet, a mixture of two algae species of known high nutritional value(Chaetocems calcitransand T-ISO).

Larvae were grown through to metamorphosis on the driedNannochlorissp. diet in 21 days, compared with 8–11 days with the control diet. Using driedNannochloris, it was shown thatT. philippinarumlarvae do not have an essential requirement for long-chain (20 and 22C) polyunsaturated fatty acids, but are able to synthesize them from shorter chain (18C) fatty acids present in the diet. The higher total carbohydrate content of the dried algae was reflected in the larvae feeding on this diet.
Thermal and biochemical characteristics of the lipids of the leatherback turtleDermochelys coriacea: evidence of endothermy
Authors: Davenport J. , Holland D. L. , East J.
Published: May 2009

Unlike other sea turtles, the leatherbackDermochelys coriaceaforages widely in temperate waters during summer and dives to abyssal depths (>1000 m) where temperatures are low. There is strong anatomical plus limited physiological evidence in favour of at least facultative endothermy. The lipids of leatherbacks exhibit features which are consistent with maintenance of a core temperature above ambient levels when in cool waters. The lipid of flipper adipose tissue freezes at a lower temperature than lipids extracted from the blubber lining carapace and plastron. Lipid freezing points in leatherbacks are lower than for tropical caimans or terrestrial sheep, but higher than for lipids taken from the blubber of a grey seal. Leatherback adipose tissues show levels of unsaturation in neutral lipid fractions intermediate between those of seals and sheep.
An investigation of methods for sampling microbial films on rocky shores
Authors: Hill A. S. , Hawkins S. J.
Published: May 2009

Chlorophyll analysis and methods of direct observation of rock surfaces under the SEM were used to estimate composition and abundance of epilithic microbial taxa. Effectiveness of different chlorophyll extraction techniques was assessed. Extraction from ground and intact rock was compared using both hot methanol and acetone extraction methods. Hot methanol extraction from intact rock provided the most accurate and precise estimates of chlorophyll content. SEM preparation methods were compared. Microbial taxa were counted under the SEM from cryostage, critically point dried and air-dried material. It was concluded that air drying was the most appropriate preparation method for SEM observation. Air drying provides reasonable estimates of microbial composition and abundance and was less time consuming so allowing an adequate number of samples to be analysed. Cumulative species number with sampling effort curves were used to establish minimal sample sizes with respect to estimates of species number. Sequential estimates of mean abundance with increasing sample size were used to determine the effects of increasing sample size on estimates of abundance of the dominant taxa. These estimates were compared at different times of the year and for two different locations. Microbial communities were found to be extremely patchy in distribution. However, sample sizes required to give good estimates of taxa number and abundance were established. These estimates were found to be similar for the main taxa at different times of the year and at different locations.
Skeletal growth bands in brittle stars: microstructure and significance as age markers
Authors: Gage J. D.
Published: May 2009

Skeletal growth banding has been studied in the vertebral arm ossicles of the shallowwater brittle stars Ophiothrix fragilis, Amphiura filiformis, A. chiajei, Ophiura ophiura and O.

albida collected from near Oban. Scanning electron microscopy of ossicle microstructure show the bands reflect differences in stereom porosity and surface relief on the surface of the wing-like fossae of the ossicle. The evidence supports the interpretation of the bands as annual growth markers, with coarse-pored stereom laid down during periods of active growth in summer/autumn whilst finer-pored stereom, that often forms ‘breaking wave’- like ridges, is formed during periods of slow or negligible skeletal growth during the rest of the year. Growth curves fitted to growth ring measurements indicate three contrasting growth strategies amongst the species examined. These data generally support recent interpretations of demographic structure reached from studies of size frequencies in samples collected from other areas in the NE Atlantic range of these species.
Concentrations of zinc and copper in the tissues of decapod crustaceans
Authors: Bryan G. W.
Published: May 2009

Concentrations of zinc and copper have been measured in 18 species of decapod crustaceans, ranging from freshwater to purely marine species. Although the intake of zinc and copper probably varies considerably, the majority of animals contain between 20 and 35 μg/g of both metals. This is probably because the concentrations in the body fluids and tissues are regulated. Reasons for differences between the concentrations of zinc and copper in the individual tissues of different species are discussed and the ways in which regulation is achieved are compared.
Line-fishing on the continental slope. II
Authors: Forster G. R.
Published: May 2009

From 1964 to 1967, 163 deep-sea fish have been caught from 28 line hauls in depths of from 1000 to 3300 m. Slightly over half the total catch consisted of elasmobranchs. The largest individual fish was a shark Pseudotriakis microdon of 2·25 m length taken from 1400 m. The distribution of the eleven species taken regularly in these and previous hauls is compared and contrasted.
The treatment of food by prosobranch veligers
Authors: Fretter Vera , Montgomery Margaret C.
Published: May 2009

A study of nineteen species of monotocardian veligers belonging to eight different superfamilies reveals the uniformity of structure of the alimentary tract up to the time of metamorphosis. Results of feeding experiments with nineteen species of unicellular algae show that there is also uniformity in the functioning of the gut.
Temperature-dependence of fish muscle AMP-aminohydrolase
Authors: Makarewicz W.
Published: May 2009

The effect of temperature on the rate of reaction catalysed by crude muscle AMP-aminohydrolase from two species of elasmobranch and two species of teleost fish has been investigated at low substrate concentration in the range of temperature 5–50 °C.

The enzyme from teleost fish shows a very broad temperature optimum around 30 °C. The reaction rate of the enzyme from elasmobranch fish is strongly dependent on temperature. The optimum temperature for the enzyme from thornback ray lies around 40 °C. Both crude and 500-fold purified AMP-aminohydrolase from thornback ray show the same temperature-dependence.
Sublittoral hard-substratum communities off Orkney and St Abbs (Scotland)
Authors: De Kluijver M. J.
Published: May 2009

During the summer of 1990 the sublittoral communities on hard substrata were investigated at 32 localities off Orkney and St Abbs (Scotland). The environment in both places has an open coast character, with small seasonal fluctuations in temperature and salinity and a high transparency of the water. The major governing environmental factors are the available amount of daylight and the degree of exposure to water movement. For the photic zone two different communities, dominated by foliose algae, are described. Under exposed conditions a widespread community is found, dominated by red algae in the middle structural layer and characterized by a dense canopy of Laminaria hyperborea. Under more sheltered conditions a community occurs in which brown and green algae become more abundant in the middle structural layer, while the top layer is formed by Laminaria saccharina and Saccorhiza polyschides. In the aphotic zone, under exposed conditions, a community is found which consists of a number of variants, with a dominance of the suspension feeders Pomatoceros triqueter and Alcyonium digitatum or bryozoans and hydrozoans. These variants are found in different regions, depths and angles of inclination of the substrata. Comparable variants have also been found off Helgoland (German Bight). Under sheltered conditions the suspension feeders become of minor importance and the community is dominated by encrusting red algae. In a surge tunnel in the photic zone off St Abbs Head, a community dominated by Dendrodoa grossularia and Clathrina coriacea is present.
Nassarius reticulatus (Nassariidae: Gastropoda) as an indicator of tributyltin pollution before and after TBT restrictions
Authors: Bryan G. W. , Burt G. R. , Gibbs P. E. , Pascoe P. L.
Published: May 2009

Between 1984 and 1993, levels of imposex (the induction of male characters including a penis on females) were measured in gastropods Nassarius (Hinia) reticulatus (L.) at localities in south-west England. Since tributyltin (TBT) was thought to cause imposex, concentrations in tissues and sea-water were also determined. Measurements made prior to the restriction of TBT usage in 1987 showed that intensities of imposex were related to TBT levels in females. Tissue concentrations were also related to those of sea-water and concentration factors (dry tissue/water) were approximately 30,000 at 10 ng Sn I-1 and 75,000 at 1 ng Sn I-1. Penis development in females was initiated at about 1 ng Sn I-1 and in this respect JV. reticulatus appears less sensitive to TBT than the dog-whelk Nucella lapillus.

As result of the TBT restrictions, concentrations in sea-water and tissues at some of the more polluted sites decreased by factors of 5–10 times between 1987 and 1993. However, population imposex declined very slowly. This was attributed to the longevity of the snails, the slow decline of penis-length in older females and the limited recruitment of less-affected females.

It was concluded that N. reticulatus is a useful alternative to N. lapillus as an imposex-based TBT indicator at contaminated sites. However, when environmental TBT concentrations are declining fairly rapidly, analysis of N. reticulatus tissues provides a far better indication of change than measurements of population imposex.
Parasites of Buccinum undatum (Mollusca: Prosobranchia) as biological indicators of sewage-sludge dispersal
Authors: Siddall R. , Pike A. W. , McVicar A. H.
Published: May 2009

The common whelk, Buccinum undatum L., was selected as a model host-parasite system in a seasonal study at an ‘accumulating’ sewage-sludge dump-site in the Firth of Clyde, Scotland, where marked spatial concentration gradients exist for a variety of trace contaminants in the sediments. A total of 2808 whelks was examined from seven sites over 18 months. The prevalence of larval digenean parasites increased significantly with distance from the dump site from approximately 2% on its periphery to 15.1% at a reference site 3 km from the centre. At a second reference site, 13 km from the dumping area, 19.7% of Buccinum were parasitized. The effects of site, season, sex and parasitism on growth and condition of Buccinum and exposure to sewage sludge on the age-prevalence relationship and host response to infection were examined. Age-frequency distributions of Buccinum were used to compare various sources of mortalities (natural, fishing, pollution and parasite-induced). Patterns in parasite prevalence recorded at the dump site were not correlated with any natural environmental or host-related factors that were examined. The gradient in parasitism in Buccinum is considered to result principally from the toxic effects of trace metals on the miracidium, reducing parasite transmission to the molluscan host. The Bucrinum-parasite system may therefore provide a sensitive and valuable biologically-based index of the dispersal of these contaminants around the sewage-sludge dump-site, and may have wider applications for marine environmental monitoring.
Age, growth and maturation of the loliginid squids Alloteuthis africana and A. Subulata on the west African shelf
Authors: Arkhipkin Alexander , Nekludova Nataly
Published: May 2009

Samples of two loliginid squids Alloteuthis africana and A. subulata were collected from the continental shelf off the west Sahara in August-September 1987. Statoliths were taken from 124 specimens and processed using statolith ageing techniques. Statoliths of both species were very similar in shape. In the ground statolith, growth increments were examined and grouped into four growth zones distinguished mainly by the width of the increments. Age of adult mature males of both species did not exceed eight months, that of females six months. Alloteuthis africana grew faster than A. subulata in weight and, particularly, in length. At age 180 d the mantle of A. africana was twice as long and the body weight 1·2–1·5 times as large. Both species matured over a wide range of sizes and ages (from 120 to 180 d). The life span of A. africana and A. subulata hatching between January and May on the west Saharan shelf is about six months, much shorter than that of A. subulata in its northern temperate range.
Statolith Microstructure and Maximum age of Loligo Gahi (Myopsida: Loliginidae) on the Patagonian Shelf
Authors: Arkhipkin Alexander
Published: May 2009

Statoliths of Loligo gahi were sampled in the fishery region 45–47°S on the Patagonian shelf during September 1989. Peculiarities of the growth zones in the ground statoliths of adults are described. Maximum age of large maturing and mature females (130–160 mm of mantle length, ML) was estimated to be 325–345 d, that of large mature males (250–290 mm ML) ranged from 360 to 396 d.

The squid Loligo gahi d'Orbigny, 1835, occurs in temperate shelf and upper slope waters of the Atlantic and Pacific coasts of South America and is caught commercially by the international fleet in the southern part of the Patagonian shelf within the Falkland Islands Interim Conservation Zone (FICZ) (Roper et al., 1984; Csirke, 1987). Occasionally, dense shoals of L. gahi appear in the fishery region 45–47°S off the Exclusive Economic Zone of Argentina (EEZA) and have been caught in significant numbers by trawlers at depths of 120–150 m in September-October (Chesheva, 1990). Loligo gahi is a medium sized loliginid; in Falkland waters males attain 350 mm ML, females 210 mm ML (Hatfield, 1991), while in the fishery region 45–47°S maximum size is 260 mm and 160 mm, respectively (Chesheva, 1990). Patterson (1988) revealed two Falkland spawning stocks of L. gahi of unclear status, spring-spawners and autumn-spawners (austral seasons) and pointed out that the life span of squid of each stock lasted ~1 y. Recently Hatfield (1991) used statoliths to elucidate Patterson's (1988) estimations of age and growth of Falkland stocks of L. gahi and confirmed the 1-y duration of L. gahi's life span.
On a Remarkable New Scyphomedusan
Authors: Russell F. S.
Published: May 2009

A new scyphomedusan is described which was collected on a dive by U.S. research submersible Deepstar 4000 at 723 m. in the San Diego Trough. The specimen was incomplete. It is characterized by a gastro-vascular canal system in the form of a uniform network, and by the unusual form of its gonads. Its systematic position is uncertain. The medusa is named Deepstaria enigmatica gen.nov., sp.nov.
Spiracular Gills in the Marine Fly Aphrosylus and their Relation to the Respiratory Horns of Other Dolichopodidae
Authors: Hinton H. E.
Published: May 2009

The larva of the dolichopodid fly Aphrosylus celtiber Haliday is an omnivorous carnivore in the intertidal zone. It pupates in an air-filled cocoon of debris and a secretion of the labial glands. The pupa has plastron-bearing spiracular gills that have been evolved from respiratory horns similar to those of recent terrestrial Dolichopodidae.

Although the spiracular gills are pupal structures, they are the chief respiratory organs of the young adult, i.e. the pharate adult, before it emerges from the cocoon. At the pupal-adult apolysis the layer of epidermis that secreted the gill wall and the layer that secreted the spiracular atrium are left behind in the lumen of the gill, together with blood, as the body wall epidermis retracts away from the pupal cuticle. A thin sheet of cuticle, the basal membrane, is secreted across the opening into the gill lumen at this time. The epidermis and blood in the gill lumen are thus completely isolated from the haemocoele of the living animal by the basal membrane, a layer of moulting fluid, and the adult cuticle. The tissue contained in the respiratory horns of terrestrial Dolichopodidae is isolated in a precisely similar manner.

The tissue isolated in the lumen of the gill of Aphrosylus does not degenerate until after the pupal-adult ecdysis. It seems to be discarded because, on balance, its loss is less damaging than the cost that would be incurred in other ways by its absorption or retraction into the body of the adult. For instance, in order to absorb the tissue in such long appendages, or to retract all of the epidermis from within them, would necessarily prolong the moulting period, a period when the insect is particularly vulnerable.
The Tube-WormSpirorbis Vitreusand its Distribution in Britain
Authors: Crisp D. J. , Bailey Julie H. , Knight-Jones E. W.
Published: May 2009

Spirorbis vitreus(Fab.), an arctic form, seems to be absent from Wales and most of England, but is generally abundant off the west coast of Scotland and also occurs in certain localities off Ireland, the Isle of Man, Cornwall and Brittany (which is probably its southern limit in Europe). Its range thus extends farthest down our western coasts, a distribution which is characteristic of various other northern and southern forms that are near the limits of their geographical ranges. Such species presumably benefit from the equable temperatures, adjoining deep water, and this winter-breeding species ofSpirorbisalso needs freedom from abrasion.

The tubes of juvenileS. vitreusare very different from those of adults. The distribution of uncini on the abdomen shows a remarkable bilateral asymmetry, as inS. spirillum.
The Component Combined Amino Acids of Some Marine Phytoplankton Species
Authors: Chau Y. K. , Chuecas L. , Riley J. P.
Published: May 2009

Gas-liquid and thin-layer chromatography have been used for the determination of 25 amino acids in the hydrolysates of 25 species of marine phytoplankton which had been grown in Erd-Schreiber medium. The general pattern of their distribution agrees with that found by earlier workers; the principal amino acids being glutamic acid, alanine, leucine and aspartic acids. Small amounts of 2-amino-n-butyric and 2-amino-iso-butyric acid together with compounds which have been tentatively identified as 4-amino-n-butyric acid and the 2-amino- and 2,5-diamino derivations of adipic acid were detected in many of the organisms. No differences were found which could be related to the taxonomy of the organisms.
Observations on Kylinia Rosulata From S.W. England
Authors: Boney A. D. , White E. B.
Published: May 2009

A description is given of the minute epiphytic red alga Kylinia rosulata Rosenv. from collections made in the Plymouth area, and from old herbarium material. The diagnostic characters of this and related species are discussed.

The minute epiphytic red alga Kylinia rosulata (order Nemalionales, sub class Florideophycidae) was first described by Rosenvinge (1909) from dried specimens of Sporochnus pedunculatus (Huds.) Ag., collected from the Northern Kattegat. Kylinia was observed on the terminal assimilatory filaments of the supporting plant. Since the original description, this small plant has had a somewhat confused history from both the taxonomic and nomenclatural points of view. Feldmann(1963) has recently summarized the available data, and has verified the validity of the genus and species as originally described by Rosenvinge (see also Feldmann, 1958). K. rosulata is characterized by the possession of short prostrate filaments arising from a single attaching cell, each cell containing a parietal chromatophore, and with male plants bearing a hyaline hair-like body—called the ‘androphore’ by Rosenvinge (1909) and ‘spermatocystophore’ by Feldmann (1958).
Some Effects of Salinity on the Survival, Moulting, and Growth ofCorophium Volutator[Amphipoda]
Authors: Mclusky Donald S.
Published: May 2009

An experimental study of the effects of salinity on the mud-dwelling amphipod,Corophium volutator(Pallas), indicates that, if supplied with mud, it will survive the salinity range of 2.50 %0, and without mud the range 7.5-47–5 %0. Moulting occurred in salinities of 2.6–46 %0, but most frequently in the range 5–20 %0. Growth occurred at a maximum rate in 15.4 %0, and only slightly slower at 4.4 and 30.6 %0; but below 4.4 %0the growth rate was progressively reduced. Freezing point studies showC, volutatorto be a hyperosmotic regulator, having a tissue tolerance range of 13–50 %0. The importance of a supply of mud, and the significance of hyperosmotic regulation are briefly discussed.

INTRODUCTION

The amphipodCorophium volutator(Pallas) is an inhabitant of littoral muds, the populations often reaching high densities. It has been most commonly reported from shores of estuaries, although Zenkevitch (1963) has stated that it may also occur in muds submerged to a depth of 10 m. Segerstråle (1959) has summarized the data available on the occurrence and distribution ofC. volutator. Since that date, work has been done on substrate selection (Meadows 1964a–c), on burrowing behaviour (Meadows & Reid, 1966) and on rhythmical swimming activity under tidal control (Morgan, 1965). Many authors (Nicol, 1935; Thamdrup, 1935; Beanland, 1940; Spooner & Moore, 1940; Rees, 1940; Goodhart, 1941; Stopford, 1951; Rullier, 1959; Gee, 1961) have described the substrate in whichC. volutatoroccurs. They have agreed thatC. volutatoris found in mud or muddy sand, containing approximately 37 % silt or clay.
On the Growth at Moulting of Lobsters (Homarus Vulgaris) in Cornwall and Yorkshire
Authors: Hepper B. T.
Published: May 2009

In experiments in Cornwall and Yorkshire 214 marked lobsters (Homarus vulgarisM. Edw.) were returned after moulting. Of these a number had moulted more than once, and the separation into once-, twice- and three-times-moulted lobsters was achieved using probability paper.

There was no significant difference in growth of lobsters from the two areas. It is concluded that the best method of plotting growth in lobsters is to plot carapace length before moulting against carapace length after moulting.

It is concluded that male lobsters show arithmetic growth over the size range 68–123 mm carapace length, adding a constant mean increment of 9.8 mm carapace length at each moult.

It is concluded that arithmetic growth, with a mean increment of 8.4 mm, adequately describes the growth of female lobsters over a small size range centred on a mean size of about 85 mm, but would lead to inaccuracies over a wider size range.

The concept of arithmetic growth in relation to the general growth pattern is briefly discussed.

Introduction

In a population study a knowledge of the growth rate is essential. In crustaceans estimation of the growth rate is complicated by two factors: first, it is usually not possible to age the animals, and second, the growth rate is made up of two components, the increase in size at moulting and the frequency with which moults occur.

The present paper presents data on the growth of lobsters at a moult, obtained from field experiments conducted in Cornwall in 1957–59, and in Yorkshire in 1958 and 1960.
A Seasonal Cycle in the Testis of the Spurdog, Squalus Acanthias, and the Sites of 3β-Hydroxysteroid Dehydrogenase Activity
Authors: Simpson T. H. , Wardle C. S.
Published: May 2009

The histology of the spurdog (Squalus acanthias L.) testis was observed through a complete annual cycle. The maximum sperm accumulation coincided with the breeding time as defined by the biennial female cycle. Degeneration of spermatogonia was observed following breeding. The band of degenerate germinal ampullae was identical to that described as occurring in Scyliorhinus canicula (L.) following pituitary ventral lobectomy. This suggested a resting phase in the production of a specific pituitary gonadotrophin lasting for about four months. All spermatocytes were transformed to spermatozoa within 12 months. 3β-Hydroxysteroid dehydrogenase activity was located in semen, in Sertoli cell cytoplasm and in the lumens of mature germinal ampullae. A possible seasonal change in this activity due to the migration of the degenerate band is suggested. Interstitial cells of Leydig could not be observed.

INTRODUCTION

The Scottish-Norwegian stock of the spurdog, Squalus acanthias L., sampled for this study, was shown by Holden (1965) to make an autumn breeding migration from the region of the Orkney and Shetland isles to the breeding areas in the Minch off north-west Scotland. During January and February those females carrying embryos at the end of their second year of development move inshore and liberate their young in shallow water. At this time the ovaries of these fish contain from three to fifteen eggs ready for ovulation (Holden & Meadows, 1964), and observations suggest that copulation, ovulation and the commencement of a further pregnancy follow almost immediately. Following copulation, the spermatozoa must reach the oviducal gland at the head of the oviduct in order that the eggs may be fertilized before they are enclosed by the candle membranes.
Population structure of thornback rays Raja clavata and their movements in the Bay of Douarnenez
Authors: Rousset Jean
Published: May 2009

The population structure of the thornback ray, Raja clavata L., expressed in terms of length and sex, seems to be related to hydrological conditions prevailing on the sampling areas. In the exposed area (Cove of Bertheaume), females are more frequently captured than males, and indeed represent the entire catch in the summer. In contrast, in the relatively sheltered area (Bay of Douarnenez) a majority of adult males and immature females are caught.

After winter, only adults and juveniles of Raja clavata migrate into the Bay of Douarnenez. This bay may be a mating area for adults and also a nursery for juveniles particularly for immature females.
Depth related variation in the structure and functioning of the compound eye of the Norway lobster Nephrops norvegicus
Authors: Gaten E. , Shelton P.M.J. , Chapman C.J. , Shanks A.M.
Published: May 2009

The mobility and quantity of retinula cell proximal screening pigment, and the liability of the eyes to light-induced damage, were investigated in the Norway lobster, Nephrops norvegicus (L.), obtained from three separate populations from depths of 18, 75, and 135 m.

During the morning after capture, the migration of the proximal pigment in response to the onset of illumination below the threshold for damage varied between the three populations. In the eyes of deep water N. norvegicus, the proximal screening pigment was located close to or below the basement membrane when dark-adapted and rose to a position midway up the rhabdoms when light-adapted. In the dark-adapted N. norvegicus from shallow water the proximal pigment was located more distally than in eyes of deep water animals. After the onset of illumination, the pigment migrated distally to completely cover the rhabdoms. The amount of retinula cell proximal screening pigment was found to decrease linearly with depth.

When dark-adapted individuals from each depth were exposed to light a positive correlation was obtained between the photon fluence rate (PER) and the proportion of the retina damaged. For a given light exposure the amount of damage was highest in animals from deeper water. The PFR causing 25% damage was approximately 1 log unit higher in animals from 18 m compared to those from 135 m.

The amount of damage varied with the delay between capture of the animals and exposure to light. When exposed 2 h after capture significant differences between depths were seen but the results were influenced by the incomplete dark adaptation of some specimens.
A model of the relationship between light and primary production in an atoll lagoon
Authors: Charpy Loïc , Roubaud-Charpy Claude Julia
Published: May 2009

The Tikehau atoll (Tuamoru Archipelago, French Polynesia) is located at 14°S 148°W. Phytoplankton and sand microalgae are the most important primary producers of the lagoon. They were studied for 4 years.

The relationship between light energy and lagoonal primary production was measured by using the14C method for phytoplankton and O2method for phytobenthos. Incubations, carried outin situ, were made at different depths and light exposition times.

Irradiance was high and 17% of the light energy measured at the surface reached 25 m (lagoon average depth). Maxima of phytoplankton and phytobenthos productions occurred at low depths; there was therefore no photoinhibition of photosynthesis. Correlations between light energy and primary production were strong, especially for phytobenthos. Multiplicative linear regression models (productionvslight) associated with an exponential linear regression model (lightvsdepth), allowed planktonic and benthic primary production to be predicted from the depth and the light energy received at the surface. The benthic primary production exceeded the phytoplanktonic production in the upper 18 m. The total primary production (benthos + plankton) was constant with depth and depended only on light energy at the surface. One Einstein received at the lagoon surface allowed the growth production of 14 mg of carbon (water column + sediments).
Prorocentrum Minimum (Dinophyceae) in the Adriatic and Black Sea
Authors: Marasović Ivona , Pucher-Petković Tereza , Petrova-Karadjova Vyara
Published: May 2009

During the summer months of 1983 Prorocentrum minimum (Pavillard) Schiller, not earlier recorded from the Adriatic, constituted a considerable proportion of the regular summer bloom in the Sibenik Bay (eastern Adriatic coast). During the subsequent years (1984,1985,1986) the proportions of P. minimum in summer blooms in the Ŝibenik Bay was constantly increasing (Marasović, 1986; Marasović, in press). At the same time its presence was reported from the other parts of the Adriatic coast, attributed to the intensified eutrophication of the Adriatic waters (Pucher-Petković & Marasović, 1987; Marasović et al., 1988; Pucher-Petković et al., 1988; Marasović, 1989).
Developmental biology of marine organisms
Authors: Brownlee C.
Published: May 2009

Marine organisms have long provided ideal systems for the study of development. The reasons for this are essentially twofold. Firstly, gametes, zygotes and embryos of many species are relatively accessible, facilitating observation and experimental manipulation. Secondly, the exceptional diversity to be found in the sea allows wide ranging comparative and evolutionary studies. The aim of this meeting was to highlight significant advances in developmental biology research using marine organisms and to bring together workers from a variety of disciplines to encourage cross-fertilization of ideas and comparisons between different systems. Particular attention was paid to new approaches for solving fundamental problems at different levels of complexity and organization. The meeting was organized such that parallel developmental processes in different systems, both animal and plant, could be compared. Sessions covered egg activation/cell cycle control; polarization/early development; embryogenesis/larval development; and the interaction between development and environment. Examples were chosen from a wide range of organisms, including molluscs, echinoderms, asddians, echiuran and polychaete worms, ctenophores, copepods, amphioxus, fish and algae (Brownlee, 1993).
Regulation of gene expression in the sea urchin embryo
Authors: Coffman James A. , Davidson Eric H.
Published: May 2009

In the undisturbed sea urchin embryo, cleavage of the blastomeres is invariant and gives rise to five polyclonal territories that are each defined by the larval structures to which they give rise, and by unique programmes of gene expression. These territories are the aboral ectoderm, the oral ectoderm, the vegetal plate, the skeletogenic mesenchyme, and the small micromeres. Structural gene markers for four of these territories (all except the small micromeres, which participate in later development) have been cloned and characterized, and the regulatory domains of several of these genes have been mapped to the level of specific protein-binding sites.
Nectins in sea urchin eggs and embryos
Authors: Yokota Yukio , Matranga Valeria , Zito Francesca , Cervello Melchiorre , Nakano Eizo
Published: May 2009

The extracellular matrix of the sea urchin involves a protein with a molecular weight of 180 kDa (sea urchin fibronectin), which corresponds to mammalian fibronectin, and a nectin specific to Echinoidea with a molecular weight of 105–115 kDa (sea urchin nectin). Sea urchin fibronectin and sea urchin nectin have cell adhesion protein properties. They are, however, different from each other in biochemical properties, biological functions and intraembryonic distribution. Sea urchin fibronectin isolated from the sea urchin ovary accelerates scattering of micromere-derived cells and promotes spicule formation of micromeresin vitro. Sea urchin nectins identified so far inParacentrotus lividus(Lamarck),Temnopleurus hardwicki(Gray) andPseudocentrotus depressus(A. Agassiz) are presumably homologous molecules displayed in different species. They seem to be secreted into the hyaline layer as its constituents, and to play some role in morphogenesis of the embryo.
The molecular control of spatial patterning in amphioxus
Authors: Holland P. W. H. , Garcia-Fernàndez J. , Holland L. Z. , Williams N. A. , Holland N. D.
Published: May 2009

The embryology of amphioxus (Chordata: Cephalochordata) has features in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two taxa. Amphioxus differs from vertebrates, however, in having less complex organogenesis and cranial morphogenesis, and less specialization along the anteroposterior body axis. Here we illustrate this by describing the embryology of an amphioxus species,Branchiostoma floridae. To gain further insight into the origins, evolutionary divergence and comparative embryology of these taxa, we are comparing the molecular control of embryonic development in amphioxus and vertebrates. For these analyses, we are focusing on homeobox genes: a diverse multigene family implicated in developmental control in many Metazoa. We report the results of PCR-based experiments which reveal that the amphioxus genome has homeobox genes from several recognized gene classes. The PCR experiments also suggest that amphioxus has fewer ‘Hox’ and ‘Msx’ class homeobox genes than do vertebrates. We suggest, therefore, that amphioxus may be a living descendant from an intermediate stage in the evolution of homeobox gene family complexity, and the complexity of vertebrate developmental control. The pattern of gene expression during embryogenesis has been described for one amphioxus homeobox gene of the Hox class. This gene is primarily expressed in the presumptive neural tube of amphioxus neurulae, later embryos and larvae, in a spatially-restricted manner. The expression data lead us to suggest that Hox genes are involved in the control of spatial patterning in the neural tube of amphioxus; the data are also interpreted as giving insight into possible homology between the amphioxus and vertebrate body plans.
Developmental biology ofAcetabularia
Authors: Bonotto Silvano
Published: May 2009

Acetabularia(Dasycladaceae: Chlorophyta) is a giant unicellular marine alga possessing a single nucleus but several millions of chloroplasts and mitochondria. It presents a polar growth and a peculiar morphological differentiation, comprising the development of a branched rhizoid at its basal end, where the nucleus is located, and the formation of several seriated whorls and then a reproductive cap at the apex of the stalk.Acetabulariais particularly useful in many fields of cellular and molecular biology. Recent work and current ideas on its developmental biology are summarized and discussed.
Winter warming in the southern Bay of Biscay and Lagrangian eddy kinematics from a deep-drogued Argos buoy
Authors: Pingree R. D.
Published: May 2009

The winter of 1989/1990 was a year of marked warm water inflow along the Iberian, Spanish and French continental slopes and three anticyclonic eddies developed in the southern Bay of Biscay. Winter temperatures along the northern Spanish slope were examined in the belief that warm water inflow is related to the production of anticyclonic eddies in the southern Bay of Biscay. The annual cycle of temperature (at ~200 m depth) is most unusual in that the warmest temperatures occur in January, the coldest in the summer. Year-to-year variations are evident with the suggestion of a periodicity, though variable, of about five years.

In April 1992, an opportunity presented itself for a late winter eddy survey in the south-eastern corner of the Bay of Biscay from RRS ‘Charles Darwin’. Two Argos buoys were deployed in what was thought to be, or would develop into, an anticyclonic eddy, and one of the buoys was caught in the eddy. This buoy was drogued at a depth of 320 m in a relatively well-mixed part of the water column thought to contain the eddy core. This buoy made ~60 clockwise orbits in the eddy and remained within 15 km of the eddy centre over the 200-d observation period. The normalized relative central vorticity of the eddy had a minimum value of -0·6 and the eddy rotation period experienced by the buoy ranged from 2·5 to 6·5 d. The decay scale for the eddy was estimated at 250 ±100 d. The mean variance of the east-west velocity component was significantly larger than the north-south value, and the buoy's orbit was significantly elliptical towards the end of the period of the observations.
A check-list of the extant Haptophyta of the world
Authors: Jordan R. W. , Green J. C.
Published: May 2009

Members of the Haptophyta from British waters have been listed in a number of check-lists between 1953 and 1976 (Parke, 1953; Parke & Dixon, 1964, 1968, 1976), but there has been no attempt to draw the records together on a world-wide basis. However, a recent review of the classification system of the coccolithophorids included a check-list of all species thought to be extant from marine, coastal and freshwater habitats (Jordan & Kleijne, 1994). At the same time, two ambitious projects, theEncyclopaedia of Algal Genera(ed. B.C. Parker, in preparation) and the preparation of a CD-ROM retrieval system for information on algal and protist groups by the Expert-Centre for Taxonomic Identification (ETI), have required further collation of the available records (see Note 1), and, as a result, we have now extended the scheme of Jordan & Kleijne (1994) to include a global list of all extant haptophytes.
On the antennular secretion of the cyprid ofBalanus amphitrite amphitrite, and its role as a settlement pheromone
Authors: Clare Anthony S. , Freet Rebecca K. , McClary Marion
Published: May 2009

In exploring a substratum,Balanus amphitrite amphitriteDarwin (Crustacea: Cirripedia) cyprids deposit ‘footprints’ of antennular secretion. The results ofin vitrosettlement assays suggest that in addition to serving as a temporary adhesive, the secretion acts as a pheromone, in that its presence induces the settlement of conspecific cyprids. This result is in accord with a previous study onBalanus balanoides(L.)(=Semibalanus balanoides). In settlement assays, the pheromone is likely to contribute to an observed positive linear relationship between settlement and cyprid density. The density effect should thus be an important consideration in the design of barnacle settlement assays. In the field, cyprid searching behaviour may render a surface more attractive to settlement by cypris larvae.
On the seasonal abundance of young fish XI. The year 1966
Authors: Russell F. S.
Published: May 2009

The numbers of young fish, excluding clupeids, taken in a 2 m ring trawl in the plankton off Plymouth were as high in the year 1966 as they were during the 1920s and early 1930s. There is thus evidence that the period of decreased abundance which began after 1934 and has apparently persisted since then may have ended. The year 1966 was a very early year for spring spawners and this can be correlated with the high water temperatures prevailing in the early months of that year.
The biology of Leptomysis gracilis and L. lingvura [Crustacea, Mysidacea]
Authors: Mauchline J.
Published: May 2009

The general biology of Leptomysis gracilis (G. O. Sars) and L. lingvura (G. O. Sars) is described. There are three main generations of L. gracilis, spring, summer and autumn ones, produced during the year, although breeding is continuous in the population between the most productive periods. Females carry as many as sixty young in the spring and summer but usually less than twenty in the winter months.
Population parameters of Argentina sphyraena [Isospondyli] from west of Britain
Authors: Halliday R. G.
Published: May 2009

Introduction

Monthly samples of Argentina sphyraena L. taken in the Clyde Sea Area over 2 years were used to describe age, growth, length-weight relationship, annual cycle in condition, and mortality. Results indicate that one transparent ring is laid down in the otoliths each year between November and May, providing a means of ageing this species.
Observations on the biology of the marine Leech Oceanobdella blennii
Authors: Gibson R. N. , Tong L. J.
Published: May 2009

The biology of the marine leech Oceanobdella blennii, ectoparasitic on the littoral fish Blennius pholis, was studied on the coast of North Wales from 1964 to 1966. Leeches first appeared on the fish in large numbers in December, but were less common in January. During February and March they became more abundant on individual fish and among the host population as a whole, but in April and May the leeches began to disappear and none was ever found from June to November.