bluuebunny/crossref_metadata_2025 huggingface dataset:
The breeding biology ofIdotea pelagica(Isopoda: Valvifera) with notes on the occurrence and biology of its parasiteClypeoniscus hanseni(Isopoda: Epicaridea)
Authors: Sheader Martin
Published: May 2009

Idotea pelagicaLeach is typically found on exposed shores among barnacles and stunted fucoid algae. It has been recorded from Norway to the coast of France, excluding the low salinity waters of the inner Baltic (Naylor, 1972). Studies have been made of its feeding (Naylor, 1955a), external morphology (Naylor, 1955 b) and ecological distribution (Naylor, 1955 c).
The biology of the northern rockling,Ciliata septentrionalis, in the Severn Estuary and Bristol Channel
Authors: Claridge P. N. , Gardner D. C.
Published: May 2009

Although the initial description of the northern rockling,Ciliata septentrionalis(Collett, 1875 a,b) was based on specimens collected off the Norwegian coast in the late nineteenth century, this species was not recorded from British waters until 1960, when a specimen was found in the Clyde Sea area (Bagenal, 1961). Subsequently, northern rockling have been recorded by Wheeler (1965, 1968) from the Moray Firth and in the waters off the Isle of Man and Southern Ireland, and by Dando (1975) from the Plymouth area. A single specimen has also been captured in a rock pool on the Yorkshire coast (Wheeler, 1971). The only investigation into the biology ofC. septentrionalishas been conducted by Dando (1975), who obtained the fish from the Plymouth area, both by trawling and from cod stomachs. He outlined the early development of the egg and larva, and suggested that the northern rockling had greatly increased in abundance in the Plymouth region since 1968.
Some aspects of vision in the lobster,Homarus vulgaris, in relation to the structure of its eye
Authors: Kampa Elizabeth M. , Abbott Bernard C. , Boden Brian P.
Published: May 2009

The compound eye of the lobster H. vulgaris has a single lobe; its ommatidia are uniform except in length. Each ommatidium consists of a corneal facet, two corneagenous cells, four cone cells, a four-part crystalline cone, an elongate cone stalk, seven retinular cells and a four-part rhabdom. Growth between the zoaeal and adult stages is primarily a lengthening of the cone stalk.
On a new medusa, Krampella dubia n.g., n.sp.
Authors: Russell F. S.
Published: May 2009

In a collection made with a 2 m stramin ring trawl at 47°03′ N., 5° 47′ W. on 4 July 1956, with 800 fathoms of wire out, I have found a new species of medusa. This specimen is in a comparatively good state of preservation except that the stomach is badly damaged.

The umbrella is hemispherical and the jelly is moderately thick. The form of the stomach cannot be described for certain. Parts of it are to be seen as narrow strips hanging down from the upper ends of three of the radial canals. One of these strips is continued for a short distance along the subumbrella surface towards the summit. It has the form of two short curtains with a space between them which leads into the radial canal. It thus seems quite possible that the stomach is i n fact an open cross with mouth lips extending along each arm as in Staurophora.
The modes of action of toxic agents: II. Factors influencing the toxicities of mercury compounds to certain Crustacea
Authors: Corner E. D. S. , Sparrow B. W.
Published: May 2009

A study has been made of the toxicities of mercuric chloride, mercuric iodide and methyl-, ethyl-,n-propyl-,n-butyl-,n-amyl-,iso-propyl-,iso-amyl- and phenylmercuric chlorides to larvae of the crustaceansArtemia salinaandElminins modestus. With both species it has been found that all the mercury compounds are more toxic than mercuric chloride, that primary alkylmercuric chlorides are more toxic than the corresponding secondary compounds, and that as the homologous series of primary compounds is ascended, toxicities increase. In addition, it has been found that Elminius is much more readily poisoned thanArtemiaby each mercury compound, and that differences between the toxicities of the poisons toElminiusare much smaller than corresponding differences observed in experiments withArtemia.
Vitamin A and carotenoids in certain invertebrates VI. Crustacea: Penaeidea
Authors: Fisher L. R. , Kon S. K. , Thompson S. Y.
Published: May 2009

Vitamin A and carotenoids were measured in six species of Penaeidae and seven species of Sergestidae.

Vitamin A was present in at least one sample of all species except Gennadas borealis at concentrations mostly of the same order as previously found in other Decapoda, but usually higher in the Sergestidae than in the Penaeidae.

Carotenoids in the Penaeidae included astaxanthin and its esters, carotenes and xanthophylls, but only astaxanthin or its esters with occasional traces of xanthophylls were found in the Sergestidae.
Lernaeocera obtusa n.sp., a hitherto undescribed parasite of the haddock (Gadus aeglefinus L.)
Authors: Kabata Z.
Published: May 2009

The fishes harbouring parasites of the genus Lernaeocera can be divided, according to the presence or absence of contact with the coastal waters, into ‘inshore’ and ‘offshore’ groups. According to literature, only L. branchialis occurs commonly on hosts in both groups. The difference between this and the remaining species of the genus is explained by the existence of two different species covered by the name L. branchialis. One of these species is parasitic on cod and whiting, the other on haddock. The two species have also different intermediate hosts (flounder and lemon sole respectively) and differ in morphology of the adult male and female and in the mode of attachment to the final host.

Lernaeocera of whiting and cod is distributed mainly in the coastal area, while that from haddock extends over the whole of the North Sea. The former, but not the latter, is present outside the European continental shelf. All these differences lead to the conclusion that the two types represent two different species. The old name is retained for the parasite of cod and whiting. The parasite of haddock is the new species, to which the name Lernaeocera obtusa is given.
Chromosome numbers of Gracilaria foliifera and Gracilaria sp. (Rhodophyta) and attempted hybridizations
Authors: McLachlan J. , Van Der Meer J. P. , Bird N. L.
Published: May 2009

Two species of Gracilaria, G. foliifera (Forsk.) Børg. and G. verrucosa (Huds.) Papenf., have been recorded from the Maritime provinces of Canada (South & Cardinal, 1970), although in recent years only G. foliifera var. foliifera is listed (South, 1976). These species are also known from the British Isles (Parke & Dixon, 1976). Chromosome counts of G. foliifera (Greig-Smith, 1954: as G. multipartita) and of G. verrucosa (Magne, 1964) from the European flora suggest these are distinct species.
Sound production and stridulatory structures in hermit crabs of the genusTrizopagurus
Authors: Field Laurence H. , Evans Athale , Macmillan David L.
Published: May 2009

The cheliped stridulatory structures are described forTrizopagurus strigimanus,T. melitai,T. tenebrarumandT. strigatus.

Sound inT. strigimanusis produced during reciprocal flexion and extension of the carpo-propodite and mero-carpopodite joints of tightly apposed chelae. These underwater sounds occur as syllables, each of which is composed of damped pulses with a repetition rate of 36–303/s and a within-pulse frequency of 6–8 kHz. The maximum sound pressure level (peak to peak) 15 cm from the source was 24 dB re: 1 Pa.

The gastropod shells inhabited byT. strigimanushad a weak effect (5% pressure difference) on directional radiation of sound in the near field (5 cm) and no effect beyond 20 cm from the crabs.

Cavity resonance of the shells was predicted from a mathematical model, but only appeared important at a fundamental frequency of about 4 kHz, when tested in animals partially removed from their shells. A more significant effect was low-frequency vibration (100–300 Hz) imparted to the shells through direct contact by the hermit crab inhabitants.

Behavioural experiments suggested that the function ofT. strigimanusstridulation is defensive, particularly against conspecific aggressors. This may reduce intraspecific competition for shells inTrizopagurus.
Epidermal tags in clupeid fishes
Authors: Best A. C. G. , Whitear M.
Published: May 2009

The clupeid fishes Clupea harengus and Sprattus sprattus have small cellular tags projecting from the surface of the epidermis of the head and the margins of the scales. The tags are innervated and assumed to be tactile sensory organs. The fine structure has been investigated by scanning and transmission electron microscopy. The protruding part consists of a core of four columns of cells joined by numerous desmosomes, less firmly attached to a single layer of superficial cells. Fine, varicose, nerve fibres run under the superficial cells and end freely. Beneath the tag is a group of prominent basal layer cells and a dermal intrusion with a small nerve. No Merkel cells have been detected in the organs.
SCUBA diver-operated low-light-level video system for use in underwater research and survey
Authors: Potts G. W. , Wood J. W. , Edwards J. M.
Published: May 2009

Television cameras and video equipment are well established as tools in many areas of marine research and have been reviewed by Barnes (1963), Myrberg (1973), Harris (1980), and Holme (1984, 1985). The TV camera is usually mounted on a remote sledge (Machan & Fedra, 1975; Holme & Barrett, 1977) or submersible, often with arrays of lights, and lacks the manoeuvrability that is necessary for many types of detailed survey and behavioural recording. Commercial and industrial uses also demand high-resolution equipment that is often contained in bulky underwater cases capable of operating at great depths and well below that possible by the conventional SCUBA diver. It is not unusual for the equipment to be used in conjunction with external lighting units where natural light levels are too low for the use of ambient light, and is dependent on an external power supply normally situated in the surface support vessel or within a submersible (Sisman, 1982).
Underwater sounds of the haddock,Melanogrammus aeglefinus
Authors: Hawkins A. D. , Chapman C. J.
Published: May 2009

It has not been known with certainty that the haddock produces underwater sounds of biological significance, though various authors have suggested the possibility.

Descriptions are given of sounds (grunts and rasp-like noises) produced in particular behavioural contexts by haddock maintained in tanks, and of sounds recorded at sea and attributed to haddock. Oscillograms and a spectrogram of these sounds are given. It is suggested that the sounds are involved in aggression and self-defence.

The sound-producing mechanism is described.
Mesopsammic Cnidaria from Plymouth (with systematic notes)
Authors: Salvini-Plawen Luitfried V.
Published: May 2009

During a short stay at the Marine Biological Association Laboratory Plymouth (mid-September 1982) preliminary investigations of the interstitial fauna of marine sand were carried out. The sampling sites with the recorded Mollusca have already been communicated (Salvini-Plawen, 1984).

As concerns mesopsammic Cnidaria, only a few findings have been made in British waters (Boaden, 1963, 1966; Harris, 1972). The present contribution reports not only new records for the Plymouth area and British waters in general, but also provides comparative knowledge of mesopsammic faunas.
Underwater observations on rocks off Stoke Point and Dartmouth
Authors: Forster G. R.
Published: May 2009

A description is given of the commonest sublittoral algae and sessile animals found on rock at Stoke Point Reef and at the E. Blackstone rock near Dartmouth to a maximum depth of 28 m. The E. Blackstone fauna resembled that of Plymouth Sound. The marked change which has been found is ascribed to the greater turbidity of the water near Dartmouth and the increased shelter from wave action.
Observations in vivo on the breeding of Elminius modestus grown on glass slides
Authors: Crisp D. J. , Davies P. A.
Published: May 2009

A more complete study of reproductive behaviour is possible where observations can be made on individuals. This is especially so in a population where each individual has a succession of breeding cycles which are not synchronous with those of other individuals. Continuous records of the breeding of individual barnacles is possible in species which have a membranous base. Individuals may be grown on glass slides and the reproductive condition determined by observations through the base.

Reproduction in Elminius modestus takes the form of a succession of breeding cycles or broods, each cycle being initiated by copulation, oviposition and fertilization of the eggs in the mantle cavity. Here the eggs develop, and embryos are eventually liberated through the opercular valves.

The time interval occupied by a brood varies both among individuals and with the season of the year. The time of development of the embryos appears to be a function of temperature alone, but the regeneration of the ovary depends upon the nutrition and food supply. When the ovary regenerates rapidly, as in the period of rising temperature, viz. in spring and early summer, another fertilization follows closely upon liberation, but in autumn and winter the ovary may not mature for some time after liberation, with the result that a large proportion of the population do not contain egg masses. In spring and summer the fecundity is probably limited by the rate of development of the embryos; in autumn and winter by nutrition.

There is a slight tendency for eggs to remain in the mantle cavity for a longer period during the falling temperatures of autumn and winter than at corresponding rising temperatures in spring and summer.
On the Mode of Functioning of the Water Vascular System ofAsterias RubensL.
Authors: Binyon John
Published: May 2009

Experiments reported in a previous paper have indicated a considerable water loss by isolated preparations of the tube feet ofAsterias rubenswhen ligatured in the protracted state. Because of its specialized structure, the podial diameter remains constant throughout the stepping cycle and this simplifies the procedure for measuring the surface area. Measurements of the internal hydrostatic pressure within the tube foot ampulla systems shows a maximum of about 30 cm water to be reached during the protraction phase of the stepping cycle, falling to nearly zero during the resting period. From these data it is possible to calculate a value for the permeability to water of the tube foot membrane, and such a value is compared with other membranes.

By measurement of the total area of protracted tube foot membrane exposed by the animal when supporting itself in sea water, it is possible to arrive at a figure for the total water loss by the water vascular system. For a 50 g animal this amounts to some 0·5 ml./h. Experiments involving blocking or extirpating the madreporite, and with isolated arms, make it extremely improbable that this loss could be made good from this route.

As alternative mechanisms, a slight hypertonicity due to the presence of excess potassium, or water movement as a direct consequence of the operation of an ion pump are discussed. In view of the hydrostatic pressure within the water vascular system the possibility of its functioning as a physiological kidney is also discussed. A possible alternative function for the madreporite is put forward.
A Note on the Elemental Composition of the Jaws of Goniada Maculata (Polychaeta: Goniadidae)
Authors: Gibbs P. E. , Bryan G. W.
Published: May 2009

It has been concluded from studies of the elemental composition of the jaws of four Glycera species that a high concentration of copper is a structural feature of the glycerid jaw (Gibbs & Bryan, 1980). In Glycera gigantea Quatrefages, for example, the whole jaw when dried contains about 1–5% of copper, whilst zinc, calcium and magnesium, in roughly equal amounts, account for a further 1%. Copper is mainly confined to the distal half of the jaw and a concentration of 13% is present in the extreme tip; the other metals are more evenly distributed. Of non-metals, chlorine is concentrated in the distal tip along with the copper but sulphur is fairly evenly distributed and probably accounts for several percent of the dry weight.

In view of these findings, it was decided to investigate the Family Goniadidae, a group of worms that are closely related to the Glyceridae (and often included in that family) but which are readily separated by the different structure of the jaw apparatus and also of the parapodia (see Hartman, 1950). In goniadids the jaw apparatus consists of a pair of larger toothed jaws (macrognaths) plus dorsal and ventral arcs of smaller, H- and Y-shaped jaws (micrognaths), the whole forming a circle around the tip of the proboscis. The present observations were made on Goniada maculata Oersted, the only goniadid species present in the Plymouth area, and a total of four specimens, all about 5 cm in length, from different areas (Salcombe, Rame Grounds and Cawsand Bay: see Marine Biological Association, 1957) were examined.
The Phytoplankton Production Cycle in Belfast Lough
Authors: Parker James G. , Rosell R. S. , MacOscar K. C.
Published: May 2009

Spring and autumn phytoplankton blooms are characteristic of those temperate marine waters where thermal stratification occurs during the summer months (e.g. Raymont, 1976). However, in well-mixed coastal waters the phytoplankton production cycle may consist of a single peak of growth during the summer (Boalch, Harbour & Butler, 1978; Wafar, Le Carre & Birrien, 1983). In a recent paper, Brander & Dickson (1984) considered evidence from the Irish Sea continuous plankton recorder which reflects the phytoplankton growth cycle largely in the well-mixed areas of the sea. These data suggested a single late peak of production, in contrast to the bimodal blooms which are known to develop in the stratified areas of the Irish Sea (Burrows & Sharpies, 1973; Slinn, 1974). The purpose of the present work was to establish the production cycle for Belfast Lough, which lies adjacent to the North Channel, an area of strong tidal mixing which forms the northerly exit for water from the Irish Sea (Lee & Ramster, 1981; Howarth, 1984). There have been no previous measurements of primary production in Belfast Lough. There was considerable interest in this topic in the early years of this century when the Royal Commission on Sewage Treatment (1908) heard evidence that nutrient inputs from sewers into the lough resulted in excessive growth of the green alga Ulva, which caused a nuisance as it decayed around the shores. Although there have been no recent reports of this phenomenon, several sewage works continue to discharge partially treated effluent to the lough. An aim of this work was therefore to assess the role of anthropogenic nutrient inputs upon phytoplankton growth.
The Bigger The Fewer: Size, Taxonomic Diversity and The Range of Chlorophyll(Ide) Pigments in Oxygen-Evolving Marine Photolithotrophs
Authors: Raven John A.
Published: May 2009

There is a greater diversity of spectrally distinct chlorophyll(ide) pigments in individuals of many of the large number of higher taxa of marine oxygen-evolvers which contain only small organisms than in those few higher taxa which also (or only) have large-sized organisms. The occurrence of more types of pigment in smaller organisms can be mechanistically related to the lesser degree of self-shading in smaller organisms, thus allowing spectral diversity to be reflected in enhanced photon absorption from a given light field as a result of multiple spectral forms of chlorophyll(ide)s. This provides a mechanistic basis with ecological significance for the greater chlorophyll(ide) diversity in small marine O2-evolvers which show greater biodiversity at the level of higher taxa than do classes or divisions which are comprised only, or predominantly, of macrophytes (Ulvophyceae, Rhodophyta, Phaetophyta, seagrasses).
Effects Of Zinc/Salinity Combinations on Zinc Regulation inGammarus Duebenifrom the Estuary and the Sewage Treatment Works at Looe, Cornwall
Authors: Johnson I. , Jones M.B.
Published: May 2009

At Looe, Cornwall (south-west England), engineering problems have resulted in the Sewage Treatment Works operating on saline rather than the typical freshwater sewage input. Saline water enters the system at all stages of the tide, except low water, mainly through the open-jointed sewers embedded in the mud of the Looe River Estuary, and causes a cyclical salinity regime within the works (Jones & Johnson, in press). A consequence of this seawater intrusion is the replacement of the freshwater macroinvertebrate community commonly associated with biological filters by two species of euryhaline amphipods. In particular,Gammarus duebeniLiljeborg is permanently established at various sites in the works including the percolating filters and humus tanks (Jones & Wigham, 1988). The ability ofG. duebenito colonise and establish a breeding population at the works is probably a reflection of its wide tolerance to several environmental factors. This species is extremely euryhaline (Forsman, 1951; Sutcliffe, 1967; Pinkster, 1970) and can withstand marked hypoxic exposure (Bulnheim, 1979; Ritz, 1980). However, in addition to fluctuations in salinity and oxygen saturation, treatment works amphipods are exposed to relatively high levels of heavy metals associated with domestic and industrial inputs (Jones & Johnson, in press). Within the humus (secondary settlement) tanks, zinc concentrations are particularly elevated compared with the adjacent estuary, although there are considerable fluctuations in zinc levels experienced by animals due to the tidally based dilution of the incoming sewage (Jones & Johnson, in press).
The Use of Graphical Methods to Estimate Demographic Parameters
Authors: Grant Alastair
Published: May 2009

The demographic parameters of a population (the number of age-classes present; growth rates; mortality as a function of age and recruitment levels) are of considerable interest to marine biologists. If individuals can be aged from growth rings in their hard parts, then the estimation of demographic parameters is relatively straightforward. If this is not possible, the next best alternative is to tag or mark individuals and use data on the recapture of these to give the information required. For many marine invertebrates, neither of these options is practical and we must resort to estimating the demographic parameters by making assumptions about recruitment and the size variation between individuals of the same age and then infer the age structure of the population from its size structure. This was first done by Petersen (1891) who interpreted each mode on a size/ frequency histogram as representing a single age-class. More recently, extensive use has been made of methods which assume that the sizes of individuals of the same age will be normally distributed. The size/frequency histogram can then be decomposed into a number of normal distributions, each of which represents a single age-class. This can be done graphically (Harding, 1949; Cassie, 1954; Bhattacharya, 1967) or with computerbased numerical methods (Macdonald & Pitcher, 1979). The graphical methods seem to be the most popular and are frequently taught to undergraduate students. The same methods can be used to dissect a size/frequency distribution into components other than age-classes (Harding, 1949), but the principles are the same.
A Report on the Fauna of the Estuaries of the River Tamar and the River Lynher
Authors: Percival E.
Published: May 2009

The following is an account of a faunistic investigation covering those parts of the Rivers Tamar and Lynher which are affected by the tide, and was carried out during a period of six months from June to November, 1928.

Description of the Area.

The Tamar forms a portion of the boundary between Devon and Cornwall and flows in a southerly direction along a more or less winding course. (Chart.) The extent of the stream dealt with is from Plymouth Sound to Weir Head, some 19 miles inland measured along the water course. For about 6 miles downstream from Weir Head, the valley is rather narrow with rock exposures at different places on the convex side of bends, the water being confined to a well-defined channel with steep sides, which are uncovered by the vertical contraction of the stream at low water. The remainder of the river, down to the sea has, generally, a mud bank on each side, except at occasional bends where rock is present, which is exposed at low water by the lateral contraction due to reduction in level. The upper 4 miles of this region has narrower mud-banks than has the lower portion. These mud-banks or -flats are for the greater part more or less plane surfaces, which may slope gradually into the bed of the main channel, as happens in the lower portion of the area, or they may slope suddenly downwards at the edge, thus forming a well-marked bank to the main channel. In many cases their landward edges lie below high-water neap tide, but in others they slope imperceptibly into the adjoining land surface.
The effect of copper and zinc on the shell growth of Mytilus edulis measured by a laser diffraction technique
Authors: Manley A. R. , Gruffydd Ll. D. , Almada-Villela P. C.
Published: May 2009

The effects of copper and zinc on the daily shell growth of Mytilus edulis have been measured with a laser diffraction measuring technique accurate to 3 µm. The results show that within three days 10 ppb added copper has a significant inhibitory effect on shell growth. Longer term experiments have been undertaken which show that the effects of 10 ppb added copper become more severe as exposure time increases. Recovery of near normal shell growth does occur on transfer to clean sea water even after a 14 day exposure to this concentration. The effects of zinc on shell growth are less severe. Transferring animals from their natural environment to the laboratory causes a measurable disturbance of shell growth for up to a week.
The effects of activity, temperature and mass on the respiratory metabolism of the squid, Illex illecebrosus
Authors: DeMont M. E. , O'Dor R. K.
Published: May 2009

Oxygen consumption was measured in squid (Illex illecebrosus) ranging from 42·7 to 443·0 g. Ambient temperature increased from 8·3 °C to 18·2 °C during the experimental period. Resting rates were calculated by correcting for the percentage of time not spent in the resting posture. A 100 g squid resting at 13 °C has a predicted oxygen consumption of 31·3 ml/h, while a continuously swimming squid has an oxygen consumption of 125·0 ml/h. Oxygen consumption is almost directly proportional to body size. A 10° increase in environmental temperature would increase oxygen consumption for a squid of given mass by 6·7 times.
Seasonality of the Association Between the Ascidian, Molgula Complanata, and the Commensal Copepod, Doropygus pulex
Authors: Schmidt Günter H.
Published: May 2009

Commensal copepods were found abundantly in samples of the ascidian Molgula complanata Alder and Hancock taken from experimental panels for histological examinations (see Schmidt, 1982). As little data exists on the possible ecological importance of such association to the ascidian host (Gotto,1979 for review), the incidence of‘ infection’ was quantified in the present study over a period of 8 months.

Between 31 October 1980 and 3 June 1981 specimens ofM. complanata( 6 mm maximum diameter) were removed from panels suspended from a raft in Langstone Harbour, Hampshire; 50–125 individuals per sample. Associated copepods found in the branchial basket were:Notodelphys agilis Thorell,Botryllophilus macropus Canu, andDoropygus pulex Thorell* (cf. fig. 2 in Schmidt, 1982). The former two species occurred sporadically, but the latter consistently. Owing to the relatively large, globular size ofD. pulex (caused by very inflated brood pouches), it almost filled the space provided by the branchial basket of smallM. complanta. Hence,D. pulex was found onlyone per ascidian, although 1–3 juveniles (several copepodid stages) were often present with the adult.

On 31 October 1980,D. pulex was present in 64% of 115 animals examined. It is interesting to note that, despite such abundance,D. pulex has not been reported previously in association withM. complanata (Gotto, i960). On 28 November 1980, the incidence of ‘infection’ was still high (62 %) but thereafter declined (14 January 1981: 35 %; 10 February 1981: 34 %; 11 March 1981: 42 %) to a value of 13 % by 8 April 1981, around which it stayed until the end of sampling (3 June 1981).
The Incidence ofPolydora Ciliata and Cliona Celata Boring the Shell ofPatella Vulgata in Orkney
Authors: Baxter John M.
Published: May 2009

Poly dor a ciliata (Johnston) is a polychaete which lives in a U-shaped tube and is found in a wide variety of substrata, ranging from soft clays or muds to hard calcareous materials. Cliona celata Grant is a siliceous sponge which inhabits tunnels and galleries it has etched out in limestone, coral or molluscan shells. The effects of these two species of boring organisms on their hosts have been studied mainly for commercially important molluscs. Hannerz (1956) is the only record of P. ciliata infectingPatella vulgata L, and there is no previous record of anyCliona spp., infections.
Feeding And Absorption in Cerastoderma Eduee Under Environmental Conditions in the Bay of Marennesoleron (Western France)
Authors: Urrutia M.B. , Iglesias J.I.P. , Navarro E. , Prou J.
Published: May 2009

Physiological processes involved in energy acquisition by the filter-feeding bivalve Cerastoderma edule (L.) (Mollusca: Bivalvia) were quantified under naturally fluctuating feeding conditions imposed by tidal cycles in the Bay of Marennes-Oleron. Physiological measurements were performed during two neap and two spring tidal cycles in order to cover a wide range of seston concentrations (TPM = 15–95 mg I-1). The main effect exerted by tides on the food supply was the resuspension of bottom sediments of low organic content, leading to a strong ‘dilution’ of suspended organic matter.

Although filtration rate was found to increase with seston concentration, ingestion rate was strictly regulated by means of pseudofaeces production. Selection efficiencies for chlorophyll a (SEchl), overall organic matter (SE0), carbon (SEC) and nitrogen (SEN) were estimated and related to dietary descriptors. The following ranking was found for the efficiency with which different substrates were selected: SEchl>SEN>SEo>SEc. Absorption efficiency was found to depend on the organic content of ingested matter according to an exponential saturating function. Observed differences between carbon and nitrogen absorption efficiency were not statistically significant. Absorption rate was kept fairly constant through the wide range of seston concentrations and qualities.
The Spatial Distribution of Perkinsus Marinus, a Protozoan Parasite, in Relation to its Oyster Host (Crassostrea Virginica) and an Ectoparasitic Gastropod (Boonea Impressa)
Authors: White M.E. , Powell E.N. , Wilson E.A. , Ray S.M.
Published: May 2009

Perkinsus marinus, a protozoan parasite of oysters, is an important cause of oyster mortality in the Gulf of Mexico and along the south-eastern coast of the United States (Hofstetter, 1977; Quick & Mackin, 1971). Infections are patchily distributed on many reefs, often with uninfected oysters adjacent to infected oysters. The primary mechanism of transmission from one oyster to another is through the water (Ray, 1954; Mackin, 1962; Andrews, 1965). Because dilution rapidly reduces the number of infective elements below the dosage required to initiate new infections (Andrews, 1979), transmission is most efficient over very short distances and declines rapidly within a few metres of the source.
Distribution of the Cirratulid PolychaetesDodecaceria Fimbriata, D. ConcharumandD. Diceriain European Waters Between Latitudes 48°N and 70°N
Authors: Gibson Peter H.
Published: May 2009

The distribution ofDodecaceriain northern Europe was found for samples borrowed from museums and other collections.Dodecaceria fimbriatawas present in the coastal waters of mainland Britain and the Continent from the English Channel northwards.Dodecaceria concharumwas only found in British mainland coastal waters and on the French coast at the western end of the English Channel. It was absent where salinities were below ~34%0. The two species were sampled along the Lothian and Borders coasts and the numbers of D.concharumfell with decreasing salinity as the Firth of Forth was approached.Dodecaceria diceriawas found for the first time in the North Sea at depths of 100–200 m. The benthic salinity here is ~35%0.
A Rare Record of the Salp, Thetys Vagina (Tunicata: Thaliacea) From Western Scottish Waters
Authors: Sims David W.
Published: May 2009

There are no species of salps (Order: Salpida) indigenous to British waters. Those species that can be found, the most abundant being Salpa fusiformis Cuvier (Fraser, 1981) are carried to British and Irish waters from the open ocean of the western Atlantic. Because of this salps can be good indicators of oceanic water movements near to Britain (Fraser, 1981). The largest species of the Salpidae is Thetys vagina (Tilesius, 1802) which generally reaches ≥230 mm in total length (TL) in the solitary asexual form and ~250 mm TL in the aggregate sexual form (Metcalf, 1918; Fraser, 1981). However, a solitary form measuring 333 mm TL was caught in a trawl from the Hawaiian islands (Nakamura & Yount, 1958). The distribution of T. vagina is usually limited to warm water throughout the Atlantic, including the Mediterranean, Indian and Pacific Oceans (Berrill, 1950). Up to 1981 there have been only two records of T. vagina in British waters (Fraser, 1981). This short paper describes, to the best of my knowledge a third recording of this salp from British waters.
Synchronization between moulting in Calocaris macandreae [Decapoda] and reproduction in its epibiont Tricella koreni [Polyzoa Ectoprocta]
Authors: Eggleston D.
Published: May 2009

The ctenostomatous ectoproct Triticella koreni (G.O. Sars) occurs mainly on Calocaris macandreae (Bell) and Nephrops norvegicus (L.) but also on other Crustacea including Upogebia deltaura (Leach), Goneplax rhomboides (L.), etc. (Eggleston, 1969). Off Northumberland T. koreni occurs mainly on C. macandreae. C. macandreae moults from September to December (Buchanan, 1963).

In order to investigate how the ectoproct copes with this annual substrate loss collections of C. macandreae made in all months were examined. Some of the material was provided by Dr J. B. Buchanan; all came from mud bottoms 40 fathoms deep east of Blyth and was collected between 1961 and 1963. Ten random C. macandreae were taken from each month's collection. One periopod on each Calocaris was selected by the use of random numbers. The number of T. koreni zooids, the number of developing zooids, the number of oviparous zooids and the number of free eggs in each oviparous zooid on each selected limb were counted.

The data recorded from the ten limbs from each collection examined are shown in Table 1.

T. koreni zooids are hermaphrodite. The gonads and free spermatozoa and eggs can be seen through the translucent body wall. Spermatozoa and eggs rarely occur in quantity in the same zooid. Some zooids are so packed with sperm as to appear opaque; up to thirty-one eggs were seen in other zooids. The egg is small and unpigmented; the larva is unknown.

From November to June T. koreni colonies grow rapidly and have a high proportion of developing zooids. From July to October growth slows and reproductive activity increases.
Redescription ofNephtys AssimilisandN. Kersivalensis(Polychaeta: Phyllodocida) and a Key toNephtysfrom Northern Europe
Authors: Rainer S.F.
Published: May 2009

Descriptions of the polychaeteNephtys hombergiiSavigny, 1818 have encompassed a wide range of apparently intraspecific variation in taxonomic features such as the segment on which interramal cirri first occur, and the form and size of pre- and postsetal lamellae (Fauchald, 1963; Woolf, 1968; Hartmann-Schröder, 1971). During the examination of museum collections and of extensive ecological collections from the North Sea (Rainer, 1990) and from Danish waters, it was found that the nameN. hombergiihas been applied to three morphologically similar species,viz. N. hombergii (s.s.), N. assimilisÖrsted andN. kersivalensisMclntosh. Both are locally abundant species that may occur withN. hombergii. This paper designates a neotype ofN. assimilis, provides a full description ofN. assimilisandN. kersivalensis, and removes these species from synonymy withN. hombergii.
The seasonal abundance of the copepodite stages ofCalanus helgolandicusandPseudocalanus elongatusoff Plymouth
Authors: Green E. P. , Harris R. P. , Duncan A.
Published: May 2009

The relative abundance of the six copepodite stages (CI-CVI) ofCalanus helgolandicusClaus (Copepoda: Calanoida) andPseudocalanus elongatusBoeck (Copepoda: Calanoida) was recorded at a station in the English Channel throughout 1989. There was a pronounced seasonal variation in the abundance of the early stages. Increased recruitment from the nauplii corresponded in both species to rising primary production early in the year, producing small CI abundance peaks in March. The major period of naupliar development occurred after the April/May spring bloom. During seasonal peaks the CI and CII stages typically formed 40% of the copepodites of these species but were scarce at other times. The body carbon weight ofCalanusandPseudocalanusCIs decreased by 38% and 21% respectively from May to August, indicating an increase in food limitation for the nauplii. Summer was passed predominantly in the CIV and CV stage at low abundances.
Innervation of luminous glands in the calanoid copepod Euaugaptilus magnus
Authors: Bannister N. J.
Published: May 2009

Evidence is presented of direct innervation of the secretory cells of luminous glands in the calanoid copepod Euaugaptilus magnus (Wolfenden, 1904). Synaptic structures are present, characterized by specialized pre- and post-synaptic membranes, clusters of synaptic vesicles and pre-synaptic dense bodies. Only one type of synaptic vesicle is present; this is spherical, clear cored and 30–50 nm in diameter. Similar vesicles at synapses in other Crustacea are thought to contain the neurotransmitter glutamate. Each gland appears to be innervated separately and all four secretory cells of each gland are innervated by the same nerve, giving rise to the possibility that control can be exerted over the firing of individual luminous glands.
Molecular evolution and diversification of the vestimentiferan tube worms
Authors: Williams Nic A. , Dixon David R. , Southward Eve C. , Holland Peter W. H.
Published: May 2009

The Vestimentifera, or deep-sea tube worms, comprise an ecologically and anatomically unusual group of marine invertebrates, with poorly understood biogeography, ecology, phylogenetic affinities and evolutionary radiation. To gain insight into evolutionary diversification within the group, we have used a molecular biological approach. We report the cloning of a region of 28S ribosomal DNA from representatives of five vestimentiferan genera plus, for comparison, a polychaete and a perviate pogonophore. Phylogenetic analyses using these DNA sequences confirm thatRidgeiaandTevniaare closely related genera. The analyses also lead us to propose the hypothesis that the earliest vestimentiferan lineage to diverge gave rise to the genusLamellibrachiaonly. In addition, our comparative DNA sequence data now provide a means to use molecular methods for identification of deep-sea tube worms; we employed this approach to demonstrate that the first vestimentiferan specimen from the eastern Atlantic Ocean belongs to the genusLamellibrachia. DNA-based identification should have wide applications in the study of vestimentiferan biogeography and ecology.
Rate of Spiculogenesis in Clathrina Cerebrum (Porifera: Calcispongiae) Using Tetracycline Marking
Authors: Bavestrello Giorgio , Cattaneo-Vietti Riccardo , Cerrano Carlo , Sara Michele
Published: May 2009

The use of tetracycline marking has enabled the daily production rate of calcareous spicules in the Mediterranean calcisponge Clathrina cerebrum to be measured. Twenty-four hours after starting the experiment newly formed spicules represent about 10% of the total spicule number. No differences in this rate of spicule secretion were detected between the samples tested under light and dark conditions. The growth rate of the tetracycline-tagged spicules in Clathrina cerebrum is similar to that found for other calcispongiae using other methods.

Spicules constitute the skeleton of sponges and are the most important taxonomic character in this group. In calcareous sponges many details of the process of spicule secretion are well known (see Simpson, 1984 for review), particularly their chemical composition and crystallographic structures (Jones, 1955, 1967; Jones & Jenkins, 1970; Ledger, 1976). Ultrastructural studies were carried out on the cellular processes involved in spiculogenesis (Jones, 1970; Ledger & Jones, 1977), but little is known of the rate of spicule secretion. This phenomenon has been studied here by tetracycline marking of newly calcified spicules, triactines. Tetracycline forms complexes with calcium or other metal ions which are easily incorporated into biominerals; consequently it can be used to label the growth of biocalcified structures (Ibsen & Urist, 1962). This method is commonly used in medical research (Urist & Ibsen, 1963; Sandhu & Tonna, 1986; Milch et al., 1957; Van Linthoudt et al., 1991), and has also been employed in studies on biocalcification in marine organisms, such as echinoderms (Gage, 1992) and molluscs (Nakahara, 1961).
Ultrasonography: a Non-Invasive Tool for the Study of Structure and Mechanical Events in Marine Animals
Authors: Davenport John
Published: May 2009

Underwater ultrasonography is a useful tool for studying structure and mechanical events in live, fairly large marine animals that do not possess an unduly thick, calcified integument. The limit of discrimination with present technology is about 2 mm, so fine detail is absent; the transducer has to be within 1–2 cm of the animal being studied or attenuation of the ultrasound by sea-water will restrict penetration of tissues. The non-invasive nature of the technique makes it ideal for the study of valuable or particularly delicate animals (e.g. Eledone); there would also appear to be considerable potential for use of ultrasonography as a teaching/demonstration aid in marine biology.
Taxonomic confusion in the genus Pontocrates (Crustacea: Amphipoda) and the presence of P. arcticus in Britain
Authors: Moore P. G. , Beare D. J.
Published: May 2009

Notice is given of the presence of a previously un-reported oedicerotid amphipod species, Pontocra tes arcticus Sars, in the shallow sublittoral zone of the sandy beach at Kames Bay, Millport (Scotland). Distinguishing features from P. arenarius are the parallel-sided second coxal plates, strongly deflexed narrow rostrum and lack of sternal dark pigmentation patterns in both sexes. A key to the three species in the genus is provided.
A new genus of midwater appendicularian: Mesoikopleura with four species
Authors: Fenaux Robert
Published: May 2009

A new genus, Mesoikopleura, in the family Oikopleuridae (Lohmann, 1915), is described from several specimens collected at low mesopelagic depth (710–860 m) during different cruises using the ‘Johnson-Sea-Link’ submersibles, and from one collected by the ‘Cyana’ submersible during the ‘Gyrocean’ cruise. Three species of this new genus are described: M. enterospira, M. youngbluthi and M. gyroceanis. One of the species already described as belonging to the genus Pelagopleura is moved to the genus Mesoikopleura. Consideration of the genera closely related to Mesoikopleura leads to the division of the subfamily Oikopleurinae into two groups at the level of super genera: Labiata and Alabiata.
A Method for Measuring Growth in Living Barnacles (Crustacea: Cirripedia)
Authors: Darling Marilyn S. , Wilbur Karl M.
Published: May 2009

A buoyant-weight method is described for the non-destructive estimation of fresh weight, total dry weight, shell weight and dry weight of organic matter in living barnacles Balanus amphitrite amphitrite Darwin. The method involves developing regression equations relating weight in air of these parameters to the buoyant weight of living barnacles in sea water. Buoyant weights of barnacles can then be used with the regression equations to obtain the weight in air of these consitituents, making possible the measurement of rates of shell growth and growth in dry weight without disturbance to the living animal. The method has been developed for the analysis of groups of juvenile barnacles cultured on coverslips, ranging in total dry weight from 1 to 60 mg, and for single mature individuals from 75 to 800 mg total dry weight. The buoyant-weight method has been used to measure shell growth of 2–3 mg d-1 in barnacles of 48 mg mean initial total dry weight cultured at 28°C.
The role of water in the behaviour of an estuarine mud-flat diatom
Authors: Hopkins J. T.
Published: May 2009

The tidal rhythm of migration of the mud-fiat diatom community is a curtailed diurnal rhythm. Evidence is given of the similarity of these two oscillations in the laboratory and in the natural conditions of the estuary. However, the interference of the diurnal rhythm by water or stirring results only in one repeated rhythm on the following day; thereafter the migrations revert to a day-length-induced synchronization.
Organic acids and bases and the lag phase in Nannochloris oculata
Authors: Droop M. R.
Published: May 2009

Nannochloris oculata Droop, an obligate phototroph, has no absolute nutritional requirement for any organic compounds. However, no growth takes place in neutral media lacking base, due to the lengthening of the initial lag phase. Weak acids shorten the lag even though pH has not been altered. The lag is interpreted as the time taken for the cells to excrete sufficient weak anions to lift the carbon dioxide in solution to the minimum required for growth. Glycollate excretion is discussedin the light of this interpretation.
The grouping of herring populations
Authors: Cushing D. H.
Published: May 2009

The work of Colebrook & Robinson (1965) has shown that there are three groups of seasonal cycle in production in the north-east Atlantic. There are three ‘races’ of herring in the same area, spawning in autumn, winter and spring. Taking the dates of spawning of each ‘race’ and the date by which the larvae must have food, a connexion can be made between the herring race and the production cycle in the area in which it lives. It is assumed that the date of spawning is fixed and does not vary with environmental conditions. Once the connexion between herring race and production cycle is made, certain comparisons can be made between races in growth rate, reproductive capacity and in the variability of recruitment. It was tentatively concluded that the magnitude of the year-class in the three north-east Atlantic races must be determined before metamorphosis. After metamorphosis, herring live on the beaches where the production cycle must have quite a different character.

Introduction

Herring populations have been grouped as spring and autumn spawners ever since they have been examined scientifically. Autumn spawners have been further subdivided into early autumn (or summer) and late autumn (or winter) spawners (Johansen 1924). Since the discovery of sharp differences in fecundity and egg size between early and late autumn spav/ners (Polder & Zijlstra, 1959), the distinction between them has acquired the same status as that between autumn spawners and spring spawners. However, there are very marked differences between all three groups, and to relate them to then-calendar times of spawning it is proposed to name then ‘ autumn’ (formerly early autumn), ‘winter’ (formerly late autumn) and ‘spring’ spawners.