bluuebunny/crossref_metadata_2025 huggingface dataset:
Choanoflagellates in Southampton Water, Including the Description of Three New Species
Authors: Tong Susan M.
Published: May 2009

Forty-three species of choanoflagellates were seen during a study of the heterotrophic nanoflagellates in Southampton Water, between 1991 and 1994. The majority of the species were loricate choanoflagellates (Acanthoecidae), and this group accounted for –8% of the total heterotrophic nanoplankton during the period of study. Aloricate choanoflagellates (Codosigidae and Salpingoecidae) were less diverse, and accounted for only 3–4% of the heterotrophic nanoplankton. The seasonal occurrence of loricate choanoflagellates was studied using light microscope whole mounts, whilst more detailed studies of lorica structure were made using electron microscope whole mounts. Two new species, described in this paper, had a markedly seasonal occurrence and were only recorded during a period of 6–10 weeks each spring.
Vertical Distribution, Morphology and Diet ofProboscidactyla Stellata(Cnidaria: Limnomedusae) in Lough Hyne Marine Nature Reserve, Co. Cork, Ireland
Authors: Ballard L. , Myers A.
Published: May 2009

The vertical distribution, morphology and diet ofProboscidactyla stellata(Cnidaria: Limnomedusae) were studied in Lough Hyne over a two year period. Vertical hauls of four depth strata, 40–30 m, 30–20 m, 20–10 m and 10–0 m, were taken monthly and at 4 h intervals for a period of 48 h in July and 24 h in September 1994.Proboscidactyla stellatawas largely concentrated in the lower 20 m of the water column reaching a maximum of 21 m−3at 30–20 m depth in June 1993. An oxythermocline occurred at 25–30 m depth in the summer and autumn months of 1993 and affected the vertical distribution of the medusae. Six morphs of the species, varying in the number of gonads, were found in the lough. Bivalve veligers, which P.stellataactively selected, formed 83% of the diet.
Reproductive Biology of an Epibenthic Amphipod (Dyopedos Monacanthus) With Extended Parental Care
Authors: Thiel Martin
Published: May 2009

Dyopedos monacanthus inhabits self-constructed mud whips on marine soft-bottoms. Juveniles stay on the mud whip of their mother for extended time periods after they hatch from her brood pouch. During the main reproductive period in the spring, parental females have been observed in the aquarium and collected from the field. Specimens of D. monacanthus have been collected simultaneously from the intake filter from the sea-water laboratory. Several consecutive clutches have been found on the whip of one female. Most juveniles are small (1 mm in size), but they grow to sizes of >2 mm on the whip of their mother. In the aquarium, juveniles usually hatched immediately after the females had been attended by males. They then clung to their mother's whip for about two weeks. Most parental females in the aquarium produced three broods during a time period of about six weeks. In the field an average of 36 parental females m-2 were found in April, and an average number of 75 juveniles clung to each female's whip. The average number of juveniles found on the females’ whips declined in May and June. Many juveniles appeared in the sea-water intake filter starting in mid April. Most juveniles caught in the intake filter were between 2 and 3 mm in size which corresponds well with their size at leaving the female's whip. In mid May, all amphipods disappeared within a few days from the aquarium, when shrimp Crangon septemspinosa started to become more active again. Many big females disappeared in the field at that time too, and in mid June parental females were smaller than in the previous months. The amphipod D. monacanthus belongs in the category of epibenthic suspension-feeding amphipods. It is probably very susceptible to epibenthic predation and extended parental care is primarily a mechanism to lift very small juveniles above the viscous sublayer in the benthic boundary layer.
Microbial Flora Associated with the Digestive System ofUpogebia Stellata(Crustacea: Decapoda: Thalassinidea)
Authors: Pinn E.H. , Rogerson A. , Atkinson R.J.A.
Published: May 2009

The digestive system of the thalassinidean mud-shrimpUpogebia stellatawas investigated using scanning electron microscopy (SEM). Within the lumen of the midgut both filamentous and rod-shaped bacteria were observed. The hindgut microbial populations were dominated by dense mats of epimural rod-shaped bacteria. The gut contents were often dominated by diatoms but also contained bacteria, dinoflagellates, plant and algal fragments. Direct bacterial counts by epifluorescence microscopy along the length of the gut revealed a slight decrease in numbers within the midgut moving from the anterior to the posterior regions, and then a dramatic rise in numbers within the hindgut. Numbers decreased again in the posterior regions of the hindgut. Common in the transient / resident samples (bacterial population when gut contents were present) were enterobacteria and an unidentified fermenter conforming to an isolate named X-ferm. However, nearly 30% of the bacterial isolates remained unidentified. The resident-only bacterial isolates from the gut (determined when the gut was empty) were dominated by the X-ferm bacteria and to a lesser extent by the generaVibrioandAeromonas. With respect to the enzyme capabilities of the gut bacteria, the resident-only collection of bacterial isolates showed much higher levels of amylase, cellulase, chitinase, protease and lipase activity than the transient/resident bacterial isolate collections, suggesting that the indigenous bacteria are likely to play a significant role in the digestion of the gut contents. Thalassinidean shrimps are likely to play an important role in the breakdown of plant and detrital material, and the recycling of nutrients in marine benthic systems.
Morphology of the Eye of the Hydrothermal Vent Shrimp,Alvinocaris Markensis
Authors: Wharton Darrison N. , Jinks Robert N. , Herzog Erik D. , Battelle Barbara-Anne , Kass Leonard , Renninger George H. , Chamberlain Steven C.
Published: May 2009

The bresiliid shrimpAlvinocaris markensisis a predator that inhabits the base of sulphide mounds built by the black smoker chimneys of active hydrothermal vents at the Snake Pit site on the Mid-Atlantic Ridge. Casual examination of animals collected with theDSV ‘Alvin’ suggests that, like other biesiliid shrimp from hydrothermal vents, the eyes of this species are adapted for vision in very dim light. However, examination of the structure and ultrastructure of eyes of animals collected and immediately fixed shows that the expected massive array of photoreceptors is partially or completely missing. The eye is enlarged, its dioptric apparatus has disappeared, its screening pigment is essentially gone, and its reflecting pigment cells have formed an enlarged mass of white diffusing cells behind the expected layer of photoreceptors. In half of the animals examined, there were no recognizable photoreceptors in the retina, and in the remaining animals there were only scattered photoreceptors with poorly organized microvillar arrays of photosensitive membrane. We conclude that this species is blind despite some retinal adaptations for vision in very dim light. Apparently, the ambient light of this animal's environment is below the quit point (the minimum level that can be exploited) so that the retina has begun to degenerate by losing its photoreceptors.
The Extent and Temporal Variation of Disturbance to Epibenthic Communities in Strangford Lough, Northern Ireland
Authors: Service M. , Magorrian B.H.
Published: May 2009

Side-scan sonar and underwater video were used to determine the impact of a trawl fishery on an epibenthic community associated with the horse mussel, Modiolus modiolus in a Northern Ireland sea lough. The presence of marks caused by trawl otter-boards on the sediments could be clearly seen using side-scan sonar and changes to the epibenthos are described from the video survey. It is apparent from the side-scan sonar survey that changes have occurred in the structure of the superficial sediments on heavily trawled areas. However, there was no clear indication of temporal changes. The utility of side-scan sonar coupled with GIS techniques to detect temporal and spatial effects is discussed.
Spatio-Temporal Persistence of theAbra Alba-Pectinaria KoreniMuddy-Fine Sand Community of the Eastern Bay of Seine
Authors: Thiébaut E. , Cabioch L. , Dauvin J.-C. , Retiere C. , Gentil F.
Published: May 2009

The spatial distribution and temporal variations of theAbra alba-Pectinaria korenicommunity from the eastern part of the Bay of Seine were investigated through four winter surveys (1986, 1987, 1988 and 1991). A grid of 40–67 stations was sampled each year using a Hamon grab (0·25 m-2) for macrofauna collection and sediment analysis. The fauna was dominated by polychaetes and in a lower part by molluscs and echinoderms. Although species richness with ~100 species collected during each survey was high, total density and biomass (±SE) resulted principally from about ten dominant species, and varied between 846·9 ±163·5 and 1135·3 ±186·7 ind m-2and 23·52 ±4·41 and 27·48 ±4·45 g m-2respectively. The dominant species were patchily distributed and exhibited weak spatio-temporal fluctuations except the two bivalvesA. albaandCultellus pellucidus. Factorial correspondence analysis (FCA) of the distribution of main species among stations and automatic hierarchical classification identified five faunal assemblages which were relatively stable in space and time. The temporal stability of the community could be generated by processes of larval retention near parental population, and sediment stabilization induced by the low abundance of deposit feeders and the high densities of the tube-dwelling polychaeteOwenia fusiformis. While the sediment variables were a poor indicator of the spatial structure of the community, the salinity gradient off the Seine Estuary and post-settlement processes (e.g. food limitation and postlarval drifting) have been proposed to explain it. Comparison with an earlier survey (i.e. 1971) suggested a degree of long-term persistence of the community structure in qualitative and quantitative terms.
Adenylate Energy Charge and Metallothionein as Stress Indices in Mytilus Galloprovincialis Exposed to Cadmium and Anoxia
Authors: Isani G. , Serra R. , Cattani O. , Cortesi P. , Carpene E.
Published: May 2009

Cadmium was rapidly concentrated by Mytilus galloprovincialis (Mollusca: Bivalvia) during one week's exposure to 0–5 ug Cd ml-1 sea-water. Cadmium accumulation was determined in the gills, adductor muscle and viscera. The amount of cadmium bound to metallothionein (MT) provided a specific index of exposure to this metal. Maximum values were reached in viscera; this observation is consistent with the presence, in the viscera, of the hepatopancreas which is commonly regarded as a major site for MT synthesis. In tissues of M. galloprovincialis exposed to Cd different energy charge (AEC) responses were observed. Adenylate energy charge (AEC) values appeared to be more affected by Cd exposure in adductor muscle than in the gills and viscera. These variations could be related to an impairment of oxidative metabolism leading to a partial switch from aerobic to anaerobic metabolism. The data obtained from anoxic incubation did not show significant differences in AEC values between pre-exposed and untreated animals, with the sole exception of adductor muscle of exposed mussels.
Age and Growth of the Sea Urchin Sphaerechinus Granularis in Southern Brittany
Authors: Jordana E. , Guillou M. , Lumingas L.J.L.
Published: May 2009

Growth of the echinoid Sphaerechinus granularis from the Gleiian Islands (Brittany, France) was studied by analysis of growth zones in longitudinal cross-sections of interambulacral oral plates. The diameter-at-age data pairs were increased using a back-calculation technique, which allows for a more efficient estimation of von Bertalanffy growth curve parameters. The annual value of the skeletal growth marks agreed with the analysis of the population's size-frequency distributions taken from a previous study. Significant differences in growth and morphological parameters were observed between two populations of the archipelago in close geographical proximity and inhabiting the same type of substratum. These differences, which appear as population phenotypic responses to different hydrodynamic conditions, confirms growth plasticity in S. granularis.
Intraspecific Variations of Bioluminescence in a Polychromatic Population OfAmphipholis Squamata(Echinodermata: Ophiuroidea)
Authors: Deheyn D. , Mallefet J. , Jangoux M.
Published: May 2009

Six colour varieties were recognized in an intertidal population ofAmphipholis squamatafrom Normandy (France). Each variety exhibits its own capacity to produce light, the light emitted by the most luminous variety being 500 times more intense than that emitted by the least luminous one. Differences in luminescent capabilities observed between varieties do not seem to be due to differences in pigmentation or to be of exogenous origin. It was shown that the capability to produce light changes according to whether individuals are brooding or not, brooding individuals emitting a more intense light than non-brooding ones. This supports the defensive use of luminescence generally associated to ophiuroid production of light. However, light capabilities differ so much betweenA. squamatacolour varieties that bioluminescence could also be associated with another role in the species.
The Occurrence of Pontonia Pinnophylax (Decapoda: Natantia: Pontoninae) in Pinna Nobilis (Mollusca: Bivalvia: Pinnidae) from the Mediterranean
Authors: Richardson C.A. , Kennedy H. , Duarte C.M. , Proud S.V.
Published: May 2009

During the course of a survey into the distribution and growth of the fan mussels Pinna nobilis and Pinna rudis from the coastal waters of the Spanish Mediterranean the presence within the mussels of Pontonia pinnophylax has been recorded. Pontonia pinnophylax typically occurred in adult pairs, but occasionally solitary male individuals were found. The width of the cephalothorax is greater in females than males, whereas the chelae of the second periopods, which are unequal, are larger in males. There is a general relationship between the size of P. pinnophylax and its pinnid host; the largest individuals were found in the largest Pinna and vice versa.
Anomalies in Sepiolinae Hectocotylization
Authors: Jereb Patrizia , Stefano Mirella Di , Mazzola Antonio
Published: May 2009

Four cases of anomalies of the copulatory arm in Sepiolinae (Cephalopoda: Sepiolidae) are reported. In one case (Sepietta oweniana), both dorsal arms were modified resulting in double hecocotylization. In another specimen probably of the same species the copula-tory apparatus was formed by two fleshy multilobed formations situated on the dorsal and ventral side of the arm base. In one specimen of Rondeletiola minor the copulatory apparatus was inversely positioned on the arm base, and in one Sepioh intermedia specimen the inner free portion of the wrinkled tubercle was markedly enlarged.
Measurement of the Adhesion of the Podia in the Asteroid Asterias Rubens (Echinodermata)
Authors: Flammang Patrick , Walker Graham
Published: May 2009

The adhesion of single podia of Asterias rubens (Echinodermata) was tested under different conditions in order to determine those factors which have an effect on the adhesive forces. In common with many other marine organisms, the adhesion of the podia is sensitive to surface properties of the substratum. The effect of immersion and emersion on tenacity (force per unit area) has been tested. Working with the asteroids completely immersed in sea-water appears to be the best technique to measure the adhesive forces of the podia. The mean tenacity of the podia of A. rubens on glass underwater is 1·98×105 Nm−2.

The measurement of the adhesion strength of marine invertebrates and of its variation under different conditions may give clues to how marine bioadhesives function. Adhesive forces have usually been measured in invertebrates using either permanent or transitory adhesion, but only rarely recorded in animals using temporary adhesion (for review see Walker, 1987).

Of all macrobenthic organisms, echinoderms have exploited temporary adhesion most efficiently. In echinoderms, adhesive systems are usually associated with the podia and are involved in locomotion, attachment, feeding, or burrowing (Flammang, 1996). The paucity of information regarding the adhesive strength of echinoderm podia is due possibly to the fact that these animals possess a multitude of podia that are not all attached at the same time, making it difficult to evaluate the exact number of podia involved in adhesion at any precise instant in time. For example, maximum detachment forces involving many podia have been measured for several asteroid species. Feder (1955) measured up to 4 kg (39·64 N) in Pisaster ochraceus, Lavoie (1956) over 3 kg (29·43 N) in Asterias forbesi, and Christensen (1957) 5 kg (49·05 N) in Evasterias troscheli. Unfortunately, the number of podia adhering to the substratum was not estimated in any of these studies. It is not possible, therefore, to calculate tenacity (adhesive force per unit of surface area) which makes comparisons impossible either between these different asteroids or with other marine invertebrates (see Walker, 1987). Tenacity has been considered in only one study (Paine, 1926) where the mean adhesive force using single podia of the asteroid A. vulgaris was 17·2 g (0·17 N), giving, when divided by a mean measurement of the surface area of the podial discs, a tenacity of 1·25×105 N m2.
The chromosomes Of Platynereis dumerilii (Polychaeta: Nereidae)
Authors: Jha A. N. , Hutchinson T. H. , Mackay J. M. , Elliott B. M. , Pascoe P. L. , Dixon D. R.
Published: May 2009

The chromosomes of Platynereis dumerilii (Audouin & Milne-Edwards) are described here for the first time. A modal chromosome number of 2n=28 was recorded, based on counts conducted on metaphase spreads prepared from 24-h-old larvae. The karyotype comprises seven pairs, each of relatively large median (arm ratio, p/q=l.00–0.59) and submedian (arm ratio, 0.59–0.33) chromosomes. Attempts were also made to band the chromosomes using C-banding and silver staining methods. C-band-positive regions were localized on four chromosome pairs (three median, one submedian). A further two chromosome pairs (both median) were observed to have terminal nucleolar organizer regions (NORs). To our knowledge, this is the first time that these banding methods have been successfully applied to any polychaete species. These results are discussed in relation to the karyotypic variation within the class Polychaeta, and the family Nereidae in particular. A stable karyotype consisting of a moderate number of large and morphologically well-differentiated chromosomes, coupled with the ease of culture under laboratory conditions and short generation time, suggests that P. dumerilii is a potentially suitable model for evaluating marine contaminants for genotoxic activity.
The application of RAPD markers to the study of the bivalve molluscLasaea rubra
Authors: Tyler-Walters H. , Hawkins A. R.
Published: May 2009

This paper describes the random amplification of polymorphic DNA markers (RAPDs) inLasaea rubra(Erycinidae: Bivalvia). Present evidence suggests thatL. rubrais an asexual species; however, the exact mode of clonal reproduction in this species is still a matter of debate. In this preliminary study, four of the primers used generated polymorphic RAPDs. One primer was able to distinguish between individuals from the same or different crevice population. This same primer also resolved a single band difference between otherwise identical RAPD patterns of a parent and its offspring. No familial differences have been detected in several previous studies using allozyme electrophoresis. This paper suggests that many polymorphic markers could be obtained with this species using the RAPD technique. Population genetic analysis ofL. rubrahas long been hampered by a dearth of polymorphic markers due to its small size. These findings suggest that this technique has the potential to further the study of population genetics in this asexual species.
Age and growth of the squid Loligo forbesi (Cephalopoda: Loliginidae) in Irish waters
Authors: Collins M. A. , Burnell G. M. , Rodhouse P. G.
Published: May 2009

Samples of the squid Loligo forbesi Steenstrup 1856 were obtained from commercial catches and research cruises in the Irish and Celtic Seas from August 1991 until October 1993. Age and growth of L. forbesi were estimated from putative daily statolith growth increment counts and from length-frequency data. Indirect evidence of the daily deposition of growth increments was obtained by counting increments on statoliths from immature female squid from successive monthly modes, during a four-month period when length-frequency growth estimates were high. Female growth estimates from length-frequency analysis (15–30 mm per month) were slightly lower than statolith-based estimates (30 mm per month). Statolith data indicated that both sexes had a life-span of approximately one year and that males grew faster and attained a larger size than females. In both sexes growth was found to be logarithmic over the size range sampled (28–505 mm mantle length). Mean estimated age of mature males and females was 317 and 312 days respectively, with the minimum age at maturity found to be 236 and 241 days. Back-calculations of hatching dates showed an extended spawning season from November to May. Squid hatched in the spring grew faster than those hatched in the autumn and winter. In post-recruit L. forbesi, growth of head, mantle and viscera were approximately isometric with body mass. The digestive gland showed slight positive allometry, whilst reproductive organs showed strong positive allometry.
The diet of corkwing wrasse, Crenilabrus melops, in Galway Bay, Ireland, and in Dinard, France
Authors: Deady Sandra , Fives Julie M.
Published: May 2009

This investigation of the diet of 801 corkwing wrasse (Crenilabrus melops: Teleostei; Labridae) from Galway Bay and a sample of 51 corkwings from Dinard has shown that this species is primarily a carnivorous feeder, taking a varied diet with molluscs and crustaceans predominating. A gradual, size-related dietary shift was apparent, crustacean food being favoured by the younger, smaller fish and molluscan food by older, larger fish. A decrease in niche breadth indicated an increase in dietary specialization with increasing length. Little seasonal variation was observed in the consumption of the major food categories. Feeding intensity, however, was influenced by the sea-water temperature. Non-feeding fish were recorded only between November and March in Galway Bay, and approximately two-thirds of the population examined in February had empty guts. Feeding intensity of males was significantly lower than that of females during the breeding season.
Nest site selection by sea turtles
Authors: Hays G. C. , Mackay A. , Adams C. R. , Mortimer J. A. , Speakman J. R. , Boerema M.
Published: May 2009

The distribution of 38 nests of loggerhead turtles (Caretta caretta) on beaches on Sanibel and Captiva islands, south-western Florida (26°26'N 82°16'W), and of 70 first digging attempts by green turtles (Chelonia mydas) on Ascension Island (7°57'S 14°22'W), was quantified. For loggerhead turtles on Sanibel and Captiva, nests were clumped close to the border between the open sand and the supra-littoral vegetation that backed the beaches. This spatial pattern of nests was closely reproduced by assuming simply that turtles crawled a random distance above the most recent high water line prior to digging. In contrast, green turtles on Ascension Island clumped their first digging attempts on the uneven beach above the springs high water line, crawling up to 80 m to reach this beach zone.
The distribution of two species of alpheid shrimp, Alpheus edwardsii and A. Lobidens, on a tropical beach
Authors: Corfield J. L. , Alexander C. G.
Published: May 2009

Alpheus edwardsii Audouin and Alpheus lobidens de Man (Crustacea: Decapoda: Alpheidae) are two intertidal snapping shrimp that burrow in association with rocks. They are morphologically similar and are often found in the same intertidal zone. The competitive exclusion theory states that two co-existing species must partition resources. The partitioning of food items as a resource appears unlikely, as gut content analyses revealed that the two species have similar diets and the relationship of shrimp condition and shrimp density indicates that food supply was not in limited supply. Instead the two species partition the resources of space within the intertidal zone, and shelter. The two species were found to exist largely in isolation from each other. Alpheus edwardsii occurred across much of the intertidal zone. Within this range A. edwardsii were most abundant in substrata with a low proportion (<50%) of mud. These substrata are better suited to their elaborate method of burrow construction. The simpler burrow construction method of A. lobidens allows this species the potential to occupy a wide range of substratum types; however, they were found only in muddy substrata with substantial surface rock cover at tidal elevations of 1.18m above datum or below. The restriction of A. lobidens to this region of the intertidal zone is probably related, in part, to their physiological requirements. In regions of co-occurrence, A. lobidens were significantly smaller than A. edwardsii, and utilized smaller rocks as shelters, thus avoiding direct interspecific competition for this resource. The absence of large A. lobidens from these areas may reflect their ability to procure shelter in competition with A. edwardsii, as behavioural experiments conducted in this study found that A. edwardsii were the dominant competitors for this resource.
Epibiotic communities on sublittoral macroinvertebrates at Signy Island, Antarctica
Authors: Barnes David K. A. , Clarke Andrew
Published: May 2009

The epibiotic communities on locally abundant macroinvertebrates, in particular the brachiopodLiothyrella uvaand the limpetNacella concinna, were examined from depths between 0 and 50 m at Signy Island, Antarctica. The percentage cover by epibionts onLiothyrellaincreased from <20% on the smallest individuals to >50% on the largest, and decreased slightly with depth. The percentage cover ofNacellaby epibionts increased with size of individual over an approximately similar range of values, but in contrast withLiothyrellaincreased greatly with depth. Cheilostome bryozoans and annelids of the genusSpirorbisformed >90% (by area) of the colonists onLiothyrellaand 30–60% onNacella, the coralline algaLithothamnionand sponges making up the remainder. The bryozoans, which generally dominated the epibiotic communities, comprised complex associations of species which could be described as either generalists, host-specific epibiotic, low specificity epibiotic or locally abundant background species. Positive associations of both occurrence and abundance were found between some of the bryozoans living epibiotically on the brachiopodLiothyrella. The overgrowth interactions recorded, between the three main epibiotic faunal taxa; sponges, bryozoans and annelids, were essentially hierarchical. Sponges usually overgrew Bryozoa, and Bryozoa overgrewSpirorbisas well as occasion-ally smothering small brachiopods. In four adultLiothyrelladeath may have been caused by the epibiotic bryozoanArachnopusia inchoatagrowing over the gape, so preventing feeding and/or respiration.
Variations in biofilms colonizing artificial surfaces: seasonal effects and effects of grazers
Authors: Anderson M.J.
Published: May 2009

The colonization of microscopic organisms, commonly called a biofilm, was examined on fibreglass panels situated intertidally at Quibray Bay of Botany Bay in New South Wales, Australia. Panels were examined by incident light microscopy, measuring percentage cover, and by a computer image analysis technique, measuring optical density. Optical density was positively correlated with and was therefore a reliable estimate of total percentage cover of the biofilm. Optical density has not been used before in this application and, although some drawbacks are discussed, it is a much more efficient sampling method than microscopic examination of panels.
Life cycle, demography, and production of Marenzelleria viridis in a salt marsh of southern New England
Authors: Sarda Rafael , Valiela Ivan , Foreman Ken
Published: May 2009

Population dynamics and production of the spionid polychaete Marenzelleria viridis were studied at Great Sippewissett salt marsh (Massachusetts, USA) for two years. Marenzelleria viridis was the main contributor in biomass and production to the macroinfaunal assemblages of the sandy organic sediments of the marsh. Marenzelleria viridis spawned during the cold part of the year and the appearance of settled larvae on sediments was observed from January to May. The density of M. viridis rose sharply from winter to late spring followed by a striking drop through summer. The estimated mean annual production of M. viridis was 60.0 g dry weight m2 during the first year and 26.3 g dry weight m2 during the second year. The population of M. viridis is affected by different processes during the year. The number of initial recruits seems to be largely governed by meteorological conditions. The numbers of recruits are then affected by competition for resources, and later, as predators become active, predation pressure determines the abundance of the population of M. viridis.
Structure of the Adhesive Surface of the Digital Tentacles ofNautilus Pompilius
Authors: Muntz W. R. A. , Wentworth S. L.
Published: May 2009

The cirri of the digital tentacles ofNautilus pompiliusare covered by annular ridges, more pronounced on the oral (adhesive) than the aboral side. On the oral side the epithelium is thicker on the proximal and outer surfaces of the ridges than on their distal surfaces. Prominent electron-dense granules occur in the cells of the thick epithelium, but are absent from the thin epithelium and the epithelium of the aboral surface. These granules contain mucopolysaccharide and may be responsible for adhesion.

The digital tentacles ofNautilusare used for attachment to, for example, prey, the substratum, or the partner's shell during mating. Their general structure and histology have been described by Owen (1832), Willey (1898), Barber & Wright (1969), Fukuda (1987) and Kier (1987). The mechanism of adhesion is still uncertain. Barber & Wright (1969) report epithelial cells of two types: pigmented cells containing pigment granules 0–5–1 µm in diameter, interspersed with a small number of mucus-producing cells which may help with the adhesive process.
Age, Growth and Sex Ratio of the Azorean Rock-Pool Blenny, Parablennius Sanguinolentus Parvicornis
Authors: Santos Ricardo Serrão , Nash Richard D. M. , Hawkins Stephen J.
Published: May 2009

The age and population structure of Parablennius sanguinolentus parvicornis (Valenciennes) (Pisces: Blenniidae) from the Azores have been studied. Total length and weight relationships are given for each sex. Age study was based on otoliths readings. The von Bertalanffy growth function was applied to describe the growth in total length with age. At the end of the first year mean (±SD) total length was significantly different in males (7.1 ±1.5 cm) and females (6.1 ±1.2 cm). One-year-old males participate in reproduction as satellites, whereas females do not. The implications of this in early growth rate of the males is discussed. During the two most important months of the reproductive season (i.e. June and July), the sex ratio was significantly biased towards males, particularly in the larger size classes.
13C/12C of organisms from Juan de Fuca Ridge hydrothermal vents: a guide to carbon and food sources
Authors: Southward A.J. , Southward E.C. , Spiro B. , Rau G.H. , Tunnicliffe V.
Published: May 2009

Soft tissue δ13C values were determined in vestimentiferan tube worms, alvinellid polychaetes and molluscs from Axial Seamount and Middle Valley, North-east Pacific. Inorganic carbon in mollusc shells and water samples was also analysed. In the vestimentiferan,Ridgeia piscesae, which lives in symbiosis with sulphur-oxidizing chemolithoautotrophic bacteria, tissue samples from the Axial vents showed δ13C values from −11 to −16‰, whereas at Middle Valley, where venting occurs through sediments, the δ13C ranged from −16 to −26‰. The tissues of an associated polychaete,Paralvinella palmiformis, which feeds on free-living bacteria, had δ13C values in the range −21 to −26‰. The bivalveCalyptogenafrom Middle Valley was more depleted thanRidgeiaandParalvinella, −37‰, closer to the ratios found in chemolithoautotrophic symbioses in non-vent habitats. Considerable, but variable, depletion (−23 to −42‰) was found in small gastropods. Mollusc shells and diluted vent water differed little in δ13C compared to inorganic carbon in ambient deep sea-water.
Blood cells of the arcid clam,Scapharca inaequivalvis
Authors: Holden Jackie A. , Pipe Richard K. , Quaglia Antonio , Ciani Graziella
Published: May 2009

Light and electron microscopical studies were carried out in order to characterize the blood cells of the bivalve mollusc,Scapharca inaequivalvis(Bruguière). Cytochemical techniques were also used to investigate peroxidase, phenol oxidase and lysosomal enzyme activity in the cells. Four types of blood cell were found: the more numerous erythrocytes and three populations of white blood cells. The red blood cells were found to be nucleated and contained dense cytoplasmic granules and various organelles; a well-developed Golgi apparatus, rough endoplasmic reticulum, variable numbers of mitochondria and fine cytoplasmic microtubules were observed. The white blood cells were generally smaller and less frequent. The type 1 cells possessed variable numbers of acidophilic, cytoplasmic granules and showed a high degree of vacuolation. The highly granular cells showed more extensive pseudopodia, perhaps indicative of intense phagocytic activity. The type 2 cells were basophilic and possessed few or no cytoplasmic granules. The type 3 cells were infrequently seen; they were relatively large and packed with large, dense, acidophilic, membrane-bound granules. Peroxidase and arylsulphatase activity was found to be present in the type 1 and 2 white blood cells and in the cytoplasmic granules of the erythrocytes. No phenol oxidase activity was detected.
Comparative foregut functional morphology of three co-occurring mysids (Crustacea: Mysidacea) from south-eastern Tasmania
Authors: Metillo Ephrime B. , Ritz David A.
Published: May 2009

Studies of mysid diets by gut contents analysis have generally revealed a broadly omnivorous feeding habit, but there are also tendencies towards carnivory, herbivory and/or detritivory (e.g. Nath & Pillai, 1973; Siegfried & Kopache, 1980; Mauchline, 1980; Zagursky & Feller, 1985; Wooldridge & Bailey, 1982; Webb & Wooldridge, 1989). Examination of feeding structures is also necessary to support inferences about feeding ecology (e.g. Webb & Wooldridge, 1989). However, there have been few studies relating to the functional morphology of mysid foreguts (Gelderd, 1909; Haffer, 1965; Nath & Pillai, 1973; Mauchline, 1980; Friesen et al., 1986; Webb & Wooldridge, 1989; Storch, 1989). With the exception of the latter two studies, qualitative descriptions and characterization of the different internal foregut structures have been primarily based on light microscopy. These studies may misinterpret the internal arrangement, topography, and three-dimensional orientation of the internal armature of the foregut, mainly due to problems with depth of field (Grice & Lawson, 1971). Oshel & Steele (1988), from SEM observations, briefly described some foregut features of Gnathophausia ingens. In a comparative study, Storch (1989), using the techniques of transmission and scanning electron microscopy, described in detail the different food chambers and channels, cuticular ridges, and ultrastructure of the epithelial and cuticular linings of the mysid foregut. Webb & Wooldridge (1989) noted the strong relationship between mouthparts, foregut morphology, and the feeding habits of two co-occurring mysids.
Age-related changes in the visual acuity of larvae of New Zealand snapper,Pagrus auratus
Authors: Pankhurst Patricia M.
Published: May 2009

SnapperPagrus auratus(Bloch & Schneider) (Pisces: Sparidae) larvae are visual feeders which initiate exogenous feeding four days after hatching. Visual acuity of cultured snapper larvae was determined morphologically from cone spacing within the retina, and improved from 2°10’ minimum separable angle (MSA) in a 4-d-old larva (3·2 mm SL) to 52’ in a fish 22 d old (5·8 mm SL). Visual acuity determined behaviourally using the optokinetic response, was poorer at the time of first feeding than acuity determined morphologically. Behaviourally determined acuity improved with growth from 38° in 4-d-old fish (mean SL 3·1 mm) to 8°8’ at 16 d of age (mean SL 4·9 mm). This was still lower than the theoretical estimate of acuity (55’ at 18 d old, 5·9 mm SL). An estimate of the Matthiessen ratio based upon histological measurements suggests that the larval eye is initially strongly myopic and grows into focus. Development of the lens accommodative system was first apparent in fish at 4 d of age as a pigmented outgrowth of the ventral iris. A retractor lentis muscle was present in 7-d-old larvae (3·5 mm SL) and suspensory ligaments were present in 10-d-old fish (3·6 mm SL). As a consequence, larval snapper were initially incapable of accommodative lens movements to correct for a refractive error. The maximum internal jaw dimensions, an estimate of maximum ingestible prey size, ranged from 152 μn at first feeding to 373 μm in a 22 d old larva. Reactive distance to prey based on MSA determined from the optokinetic response and maximum prey width, were small in first-feeding fish (0·2 mm for prey width of 150 μm), but increased linearly with both body size and prey width. Minimum separable angles of first-feeding snapper deter-mined optokinetically, were larger (lower acuity) than the visual angles determined from feeding events of first-feeding fish larvae reported elsewhere. This may reflect the fact that optokinetic experiments involve a single sensory modality and chemical sense and developing lateral line may contribute to visually oriented feeding.
Ampelisca dalmatinaandA. provincialis(Amphipoda: Gammaridea) in Irish waters
Authors: Myers A.A. , McGrath D.
Published: May 2009

The distribution ofAmpelisca aequicornisBruzelius is said to extend from Norway southwards to the Gulf of Guinea (Dauvin & Bellan-Santini, 1988) and it has been recorded from British and Irish waters (Norman, 1900; Metzger, 1875). There do not appear to be any recent records. A number of specimens in The Natural History Museum, London (NHM) collections, labelledAmpelisca aequicornis, were examined by Lincoln (1979) who reported that only Galway Bay material was referable toA. aequicornisor “at least to theaequicorniscomplex”. This we can confirm from our own study of the NHM material. We have re-examined the Galway Bay specimen referred to by Lincoln (1979) and find it to differ fromA. aequicornisin several ways and to be closest toA. dalmatinaKaraman, previously known only from the Mediterranean and the Portuguese coast (Marques & Bellan-Santini, 1991, 1993). It also closely resemblesA. pusillaSars andA. ambylopsSars, but those two species lack cuticular eyes.Ampelisca aequicornisis therefore not confirmed to occur in the waters of the British Isles.
A preliminary study on the use of acoustic transmitters for tracking juvenile bass (Dicentrarchus labrax) in an estuary
Authors: Moore A. , Pickett G.D. , Eaton D.R.
Published: May 2009

The suitability of using intra-peritoneally attached miniature 300 kHz acoustic transmitters to study the behaviour of juvenile bass (Dicentrarchus labrax) between 235 and 370 mm in length was assessed. A laboratory study indicated minimal effects on the subsequent survival and behaviour of juvenile bass. A field study carried out indicated the potential use of the transmitter for telemetry studies on juvenile bass.
Application andIn situcalibration of a pulsed-doppler flowmeter for blood flow measurement in crustaceans
Authors: Airriess C.N. , McMahon B.R. , McGaw I.J. , Bourne G.B.
Published: May 2009

The pulsed-Doppler flowmeter permits continuous, non-invasive measurement of blood flow through several arteries simultaneously. Summation of volume flow rates through all arteries leaving the heart allows determination of cardiac output, stroke volume, and the percentage of cardiac output delivered to each region of the body. The use of this system for investigating changes in arterial perfusion as well as its calibrationin situare described.
Lipid Changes During a Planktonic Feeding Sequence Involving Unicellular Algae, Elminius Nauplii and Adult Calanus
Authors: Neal A. C. , Prahl F. G. , Eglinton G. , O'Hara S. C. M. , Corner E. D. S.
Published: May 2009

Numerous studies have shown that only a small percentage of the organic carbon produced by photosynthesis in the upper layers of the oceans reaches the underlying sediments (see review by Angel, 1984). During intense phytoplankton blooms, plant cells could account for most of the organic carbon contributed to sediments in certain shallow inshore areas (Smetacek, 1980). Examination of the sediments from open ocean environments, however, indicates that the main contribution of organic carbon to these is in the form of faecal material released by zooplankton, for example salps (Iseki, 1981) and larger species of copepod (Schrader, 1971; Krause, 1981).
A Note on the Seasonal Change in Fat Content of the Autumn-Spawning Herring in the Northern Irish Sea
Authors: Wallace P. D.
Published: May 2009

Brander & Dickson (1984) observed that fish production in the Irish Sea is low compared with fish production in the North Sea. They identified the lower number of recruiting fish as being the main reason for this difference. They presented circumstantial evidence suggesting that the low recruitment of fish is in turn linked to the shorter and later production cycle in the Irish Sea but the nature of this link is not understood. An example of the way that fish populations are affected by timing of events in the plankton production cycle is provided by the annual fat cycle of herring. Many workers have shown conclusively that the fat content of the herring is intimately connected with feeding and the time of spawning (e.g. Milroy, 1907; Johnstone, 1915; Bruce, 1924; Hansen, 1955).
Rhythmical Hatching and Oncomiracidial Behaviour in the Hexabothriid MonogeneanRajonchocotyle Emarginatafrom the Gills ofRajaspp.
Authors: Whittington I. D. , Kearn G. C.
Published: May 2009

In a study of the life-cycle of the hexabothriid monogeneanRajonchocotyle emarginataby Wiskin (1970), attempts to obtain newly hatched larvae were unsuccessful, and it was decided to make a new attempt to culture eggs and hatch larvae, at the same time investigating the effects of those factors found in other monogeneans to influence hatching, such as host mucus (see Kearn, 1974), shadows (see Kearn, 1982) and mechanical disturbance (see Bovet, 1967). The success of these renewed attempts to hatch the eggs ofR. emarginataprovided an opportunity to study the behaviour of the free-swimming oncomiracidium and attempts were made to relate hatching phenomena and larval behaviour to the behaviour of the host.
The Distribution ofNucula Turgida(Bivalvia: Protobranchia) From Dublin Bay, Ireland, and the Effect of Sediment Organic Content
Authors: Wilson James G. , Shelley Colin
Published: May 2009

Recent investigations (Walker & Rees, 1980; Davis & Wilson, 1983b) have shown that the protobranch bivalveNucula turgida(Leckenby and Marshall) occupies an important niche in the ecology of Dublin Bay, where it is the dominant organism over much of the southern part of the outer bay. This is an area of moderately sorted fine sand (Harris, 1980) with a pelite (silt and clay) fraction of less than 10% and a consequently low percentage of organic matter of around 1% (Davis & Wilson, 1983b). Trevallion (1965) described theN. turgidahabitat as one of firm muddy sand, adding that the animals avoided mud due to their inability to maintain position or feeding and respiratory currents and also avoided gravel due to their inability to burrow in coarse substrates.
Reproductive Biology and Growth of the Genus Epizoanthus (Zoanthidea) From the North-East Atlantic
Authors: Muirhead A. , Tyler P. A. , Thurston M. H.
Published: May 2009

The genus Epizoanthus Gray is represented in the north-east Atlantic by three species, all of which live commensally with pagurid crabs. The shallowest-living of the three, Epizoanthus incrustatus (Duben and Koren) occurs with Anapagurus laevis (Bell) within the depth range 20–200 m (Manuel, 1981). Epizoanthus paguriphilus Verrill and Epizoanthus abyssorum Verrill are associated with Parapagurus pilosimanus (Smith), the former within the depth range 600–1550 m and the latter at 3500–4350 m.
Buoyancy in the LumpsuckerCyclopterus Lumpus
Authors: Davenport John , Kjørsvik Elin
Published: May 2009

The lumpsucker or lumpfish,Cyclopterus lumpusL. (Cyclopteridae, Scorpaeniformes), is a cottoid teleost, and, like other fish in its family, exhibits many characteristics of a coastal, bottom-dwelling fish. It is globiform, has no swimbladder, possesses a large abdominal sucker (formed from the pelvic fins), and lays demersal eggs which are brooded by the male parent for many weeks (Fulton, 1907; Cox & Anderson, 1922; Yesipov, 1937; Zhitenev, 1970; Mochek, 1973). The species spends the breeding season in shallow water, where both sexes may be seen attached to the rocks by their suckers. Early researchers (Couch, 1863; Day, 1880–4; Smitt, 1892) believed that the adults retreated to rocky bottoms in deep water after breeding. However, later workers (Cox & Anderson, 1922; Saemundsson, 1926, 1949; Andriyashev, 1954; Bagge, 1964; Blacker, 1983; Daborn & Gregory, 1983) have demonstrated that the lumpsucker spends much of its larval and adult life living epipelagically and in mid water in coastal and oceanic areas upon macrozooplankton (e.g. ctenophores, mysids). The term ‘semi-pelagic’ seems the most appropriate label for its mode of life.
Zinc Regulation in the LobsterHomarus Gammarus:Importance of Different Pathways of Absorption and Excretion
Authors: Bryan G. W. , Hummerstone L. G. , Ward Eileen
Published: May 2009

Zinc is one of the most important of the essential trace metals and more than 90 zinc-containing enymes and proteins have been discovered: furthermore, zinc increases the activity of many other enzymes (Vallee, 1978). It is not surprising, therefore, that in some groups of animals the body concentration is regulated against fluctuations in intake. Decapod crustaceans comprise one such group, although the ways in which regulation is achieved vary from species to species. In the freshwater crayfish,Austropotamobius pallipes, excretion in the faeces is a major pathway for removing zinc (Bryan, 1967a) whereas in the shore crabCarcinus maenaslosses over the body surface also assume considerable importance (Bryan, 1966). On the other hand, preliminary work on the lobsterHomarus gammarus(formerlyH. vulgaris) suggests that in this species urinary excretion plays a major role in regulation (Bryan, 1964). The present work continues the study of zinc regulation in lobsters and its main aims are: (1) to measure rates of absorption from sea water over a wide range of concentrations and study the uptake mechanism; (2) to examine absorption from the stomach under different conditions; (3) to determine the relative importance of different pathways for the removal of zinc in response to various levels of intake.