bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal and temporal aspects of recruitment and succession in an intertidal estuarine fouling assemblage
Authors: Underwood A.J. , Anderson M.J.
Published: May 2009

The recruitment and succession of fouling organisms was examined on four substrata (concrete, plywood, fibreglass and aluminium) in Quibray Bay of Botany Bay in New South Wales, Australia. Eighteen 10×10 cm panels of each substratum were submersed in each of four seasons: January (summer), March (autumn), May (winter) and October (spring) 1992. Six of each substratum were retrieved after 1 month, 2 months and 4–5 months. Thus in this study, as a methodological improvement over many other studies of succession, samples were taken independently with regard to time.

Seasonal recruitment was important in determining the pattern of succession and the composition of the assemblage. Sydney Rock oysters,Saccostrea commercialis(Iredale & Roughley), recruited in large numbers on panels submersed in January and, by their rapid growth, dominated the available space after 4–5 months. The greatest recruitment of the barnacleHexaminiussp. and the greatest percentage cover of algae (six species) occurred on panels submersed from October to March. While panels submersed in January for a period of 4–5 months resulted in a single outcome, an oyster-dominated assemblage, panels submersed in October for the same period of time resulted in a set of alternative outcomes depending on the relative abundance of barnacles and algae.
A contribution to the biology of the burrowing mud shrimp, Callianassa subterranea (Decapoda: Thalassinidea)
Authors: Rowden A.A. , Jones M.B.
Published: May 2009

Samples of the mud shrimp Callianassa subterranea (Montagu) were taken at irregular intervals (September and October 1989, April and July 1990, August 1991) from a depth of 47 m at a fixed station in the North Sea (54°35′N 04°50′E). At this site, mud shrimps appear to have a contagious distribution, the mean density varied between 38 and 59 individuals m-2 and the sex ratio was biased significantly to males (mean male: female ratio, 1·9), except for shrimps of ≥8 mm carapace length (CL) which had an equal sex ratio. The combined samples for the full sampling period showed a bimodal distribution for males and females, with a possible third mode for males, suggesting a life cycle of between 2 and 3 years. Only females ≥7 mm CL carried eggs. Lack of samples over winter prevent any conclusive description of seasonal population patterns; however, reproduction (based on the presence of ovigerous females) extended from April to September with a peak in July and post-larval shrimps (<3 mm CL) were present each month. The allometric growth of the primary chela identified male (6·5 mm CL) and female (7·5 mm CL) size at maturity. Differences in allometric growth after maturity result in males having larger and more massive primary chelae than females of equal carapace length. The parasitic isopod Ione thoracica (Montagu) infected between 20% (October) and 10–8% (August) of mud shrimps, with males having a significantly higher level of infestation than females.
Investment in eggs in lagoonalHydrobia ventrosaand life-history strategies in north-west EuropeanHydrobiaspecies
Authors: Barnes R.S.K.
Published: May 2009

Expected lifetime investment in eggs and related parameters are described for a lagoonal population ofHydrobia ventrosa(Mollusca: Gastropoda) in East Anglia, UK, and these are compared with those of East Anglian lagoonal populations ofH. neglectaand both lagoonal and intertidal-marine populations ofH. ulvae. In contrast to an earlier study on Danish populations, which suggested thatH. neglectaandH. ventrosaare at opposite ends of the hydrobiid spectrum of investment in reproduction, the order of increasing relative allocation of resources to egg production runsH. neglecta=H. ventrosa→ lagoonalH. ulvae→ intertidal-marineH. ulvae. That is, from the two small, short-lived, specialist lagoonal species producing few, large, directly-developing eggs, to the larger, potentially longer-livedH. ulvaethat produces many small eggs which develop into veliger larvae. The lagoonal populations of all threeHydrobiaspecies, however, are very similar to each other in terms of reproductive investment. When like cohorts are compared, in each, the annual egg weight is equal to the annual adult growth increment, and the weight of eggs produced per expected lifetime is half the adult growth increment at the time of death. These lagoonal populations are markedly dissimilar to intertidal-marine populations ofH. ulvae, which produce an annual weight of eggs some 15 times the annual adult growth increment, and an expected lifetime egg weight some two-and-a-half times the adult growth increment at the time of death.
Imposex and organotin compounds in Thais clavigera and T. bronni in Japan
Authors: Horiguchi T. , Shiraishi H. , Shimizu M. , Morita M.
Published: May 2009

Rates of occurrence and degrees of imposex, and tissue concentrations of organotin compounds (tributyltin, TBT; dibutyltin, DBT; butyltin, MBT; triphenyltin, TPT; diphenyltin, DPT; and phenyltin, MPT) in the rock shell, Thais clavigera and T. bronni (Mollusca: Gastropoda) were investigated at 32 sites in Japan from May 1990 to October 1992. The rate of occurrence of imposex was 100% in both species, at almost all sites surveyed. Degrees of imposex indicated by relative penis length (RPL) index reflected the pollution levels not only of TBT, but also TPT. In heavily polluted areas, many individuals were found with oviducts which were blocked by vas deferens development, and capsule glands which were filled with aborted egg masses. These organisms were thought to be sterile.
The morphometrics of cephalopod gills
Authors: Eno N. Clare
Published: May 2009

The capacity for oxygen uptake of a respiratory organ can be estimated using morpho-metric techniques, the two essential measurements being respiratory surface-area and thickness of the tissue barrier across which oxygen diffuses. In cephalopods, the gills are the main site of respiratory exchange and this study was designed to estimate oxygen uptake capacity of the gills of four different genera of cephalopods. A preliminary study was required to determine the form and structure of the gills. Light microscopy showed the surface of the gills to be highly folded, particularly inOctopus. A level of microscopy was chosen at which the outline of the smallest folds of the epithelium and the blood vessels of the gills could be easily resolved. Stereological techniques were then employed to obtain values for the respiratory surface-area related to body weight (cm2g-1), tissue barrier thickness (μm) and oxygen-diffusing capacity (ml O2min1Torr·1kg1). Values for these three variables obtained for the different species were as follows:Octopus vulgaris2·9 cm2g-1, 10 μm, 0·05 ml O2min-1Torr-1kg1;Alloteuthis subulata10·6 cm2g1,6 μm, 0·27 ml O2min-1Torr-1kg-1;Nautilussp. 4·9 cm2g-1,15 μm, 0·05 ml O2min-1Torr1kg-1;Sepiahatchlings 13·3 cm2g-1, 4 μm, 0·52 ml O2min-1Torr-1kg-1.
Wave activity on the sea-bed of the english channel
Authors: Grochowski N.T.L. , Collins M.B.
Published: May 2009

Long-term surface wave records from various parts of the English Channel are used to determine the percentage of time during a year for which waves disturb the sea-bed. Most of the bottom sediments are rarely disturbed by waves (<1% of the time), due to water depth and sediment grain size. The coastal zones (<30 m), including the embayments, experience significant wave disturbance at the sea-bed (i.e. >5–10%). The general distribution of surficial sediments can be explained in terms of tidally-induced processes alone. Even in areas where wave activity is high, fine-grained sediment transport is controlled by the same mechanisms.
Some Parasites of Sagitta bipunctata
Authors: Lebour Marie V.
Published: May 2009

Sagitta has been several times noticed as a host for various parasitic worms, notably a larval nematode and several trematodes. Larval cestodes have also been seen in it. It is exceeding voracious and apparently eats almost any animal food, especially its own species and small Crustacea, so that it is not to be wondered at if it forms a convenient intermediate host for many worms, and as Sagitta itself is an important fish food it naturally follows that the adults of these parasitic worms are usually found in fish as their final hosts. So far, however, the life histories of the larval forms hitherto found have not been determined, so we are pleased to be able to identify two trematodes belonging to well-known species which inhabit Sagitta as intermediate host and fish as the final host.
Post-Larval Teleosteans collected near Plymouth during the summer of 1914
Authors: Allen E. J.
Published: May 2009

Table XLV. is perhaps of interest, as showing the composition of the catch obtained with the young-fish trawl at different times of the year. It has been obtained by combining certain groups of hauls made in 1914 in the offshore waters outside Plymouth, all of them being beyond the 20-fathom line. As far as the conditions are concerned therefore the different groups are fairly comparable. The figure given for each species is the average number of specimens per haul for the group. It will be seen that after June the number of species present as well as the average number per haul are both very much reduced.
The morphology of Patella spp. juveniles in Britain, and some phylogenetic inferences
Authors: Bowman R. S.
Published: May 2009

Juveniles of Patella spp. in Britain are shown to be easier to classify than adults, on shell morphology alone, because of a species-specific difference in number and arrangement of the post-larval mantle tentacles. The limpets can thus be clearly divided into three distinct spp.: P. vulgata Linn., 1758, P. aspera Roding, 1798, and P. depressa Pennant, 1777, which confirms recent evidence from gel-electrophoreric studies. As the limpet grows, this initial difference gives rise to many of the variables of shell shape and colour upon which adult identification is based. In the process, it can be influenced by environmental factors to the extent of producing confusing phenotypes such as those hitherto supposed to be hybrid or genetically transitional forms. The characters described suggest that, contrary to current opinion, P. aspera and P. depressa are related more closely to each other than to P. vulgata; they may also have some bearing on the species' success and distribution in the British Isles.
A re-examination of mucus feeding by the sea cucumberLeptopentacta ( = Cucumaria) elongata
Authors: Fankboner P. V.
Published: May 2009

From observations in the aquarium and by a morphological study of the feeding tentacles it is concluded thatLeptopentacta elongatais not, as is commonly supposed, a mucus suspension feeder, but feeds on deposited material by mechanical entrapment with the aid of sticky papillae on the tentacle buds.
The effects of lowered salinity upon Branchiostoma lanceolatum from the English Channel
Authors: Binyon J.
Published: May 2009

Previous work has indicated that, although in possession of numerous supposedly osmoregulatory structures, Branchiostoma lanceolatum from the English Channel is unable to regulate its body weight in diluted sea water. In vitro measurements of the rate of flagella activity in those organs similarly indicates no increase under hypo-osmotic stress. There is however quite a sharp threshold around 18‰, below which flagella activity ceases quite abruptly. A similar situation obtains with the gill cilia although the animal can remain alive at these salinities for a period of several weeks.
Copper accumulation by the polychaete Melinna palmata: an antipredation mechanism?
Authors: Gibbs P. E. , Bryan G. W. , Ryan K. P.
Published: May 2009

Analyses of the ampharetid polychaete Melinna palmata have shown that this species consistently contains a high concentration of copper. The related species Melinna cristata also has a high copper content but Ampharete acutifrons and Amphicteis gunneri have low copper contents. M. palmata usually contains copper in concentrations in excess of 600 μg/g (dry weight) and often above 1100 μg/g; much of this copper is embodied in the branchiae which have concentrations of 0·4–1·2% copper and, although these organs account for only 3–4% of the dry body weight, their copper content represents 30–40% of the total body burden. X-ray microanalysis shows the copper in the branchiae to be concentrated in special epidermal cells. The function of the copper in these cells does not appear to be associated with detoxication, luminescence or an antifouling mechanism but feeding trials have shown the branchiae of Melinna palmata, but not of Ampharete acutifrons, to be distasteful to certain small fish. Thus it is thought the copper may reduce the palatability of the tissues and is accumulated by Melinna palmata as a chemical defence against predation.
A functional interpretation of coxal morphology in Epimeria cornigera (Crustacea: Amphipoda: Paramphithoidae)
Authors: Moore P. G.
Published: May 2009

Coxal plates 1–5 of Epimeria cornigera form a closely interlocking series keyed by the head such that ventral flexion of the peraeon is severely curtailed. The clamp formed by coxae 4 and 5 is interpreted as an adaptation facilitating copulation in a species with feeble gnathopods and non-prehensile antennae. The morphology of the posterior three pairs of peraeopods can also be regarded as an adaptation for gripping the female. Other possible functions (e.g. predator deterrence and feeding grip) of coxal structures are also examined.
Taxonomic studies on british and irish amphipoda. the genus Photis with the re-establishment of P. pollex (=P. macrocoxa)
Authors: Myers A. A. , McGrath D.
Published: May 2009

Three species of Photis Krayer are recorded from British and Irish waters. P. pollex Walker is re-established as a distinct species, synonymous with P. macrocoxa Shoemaker which becomes a junior synonym. A key to the British and Irish species is given, together with figures and descriptions of P. pollex and P. reinhardi. P. tenuicornis which is doubtfully recorded from these waters is also figured.
Reproductive biology of the serpulid Ficopomatus (Mercierella) enigmaticus in the Thames Estuary, S.E. England
Authors: Dixon D. R.
Published: May 2009

Details of the gross cellular changes taking place in the gonadial tissues and coelom of Ficopomatus during the annual reproductive cycle are presented. There is no true gonad in either sex; instead, germ cell precursors are produced by divisions of a germinal epithelium associated with the ring blood vessels in the intersegmental septa.

Segments producing gametes do not all develop simultaneously; the posterior segments are generally at a more advanced stage of sexual maturity. The later stages in gamete development take place free in the coelom, where nourishment is supplied presumably by the mobilization of materials formerly stored in tissues surrounding the gut.

Spawning commences in June and continues through to October, with peak activity coinciding with the period of high water temperature in August and early September. The adult population comprises males, females, and protandrous hermaphrodites which in the male phase become sexually mature in advance of the rest of the population, and as females later on. These transitional individuals are thought to contribute a negligible amount to the effective reproductive output in those populations living where there is marked temporal constraint on the period of reproduction.

The different reproductive capacities of temperate and tropical Ficopomatus are considered.
Some Cases of New Growths in Fish
Authors: Drew G. Harold
Published: May 2009

This specimen, obtained from one of the Plymouth trawlers, consisted of a large tumour on the dorsal surface, near the left angle of the fin (see Figs. 1 and 2). Only part of the fish was available for examination, so the presence of metastases and other details could not be determined.
Some Notes upon the Feeding Habits of Mackerel and certain Clupeoids in the English Channel
Authors: Bullen G. E.
Published: May 2009

Several previous authors have shown that the food of the mackerel, when in coastal waters, is of two different kinds, and that the fish adopts two distinct methods of procuring it. In the first place it feeds by a system of filtration upon planktonic organisms, and secondly upon prey of a larger character which is hunted by sight.
The Diet of Sperm Whales (Physeter Macrocephalus) Captured Between Iceland and Greenland
Authors: Martin A.R. , Clarke M. R.
Published: May 2009

The stomach contents of 221 sperm whales were examined at the Icelandic whaling station between 1977 and 1981. Evidence of at least eight species of fish and 22 species of cephalopod was found, together with an assortment of foreign bodies including rock fragments and fishing nets. Fish remains were found in 87% and cephalopods in 68% of the sperm whale stomachs in this area, but quantification of dietary input is complicated by differential rates of digestion and variation in the retention of indigestible remains in the stomach. Prey species are benthic or pelagic in habit and are caught by the whale in waters from 400 m to at least 1200 m in depth. One fish, the lumpsucker Cyclopterus lumpus, forms a major part of the diet. Ninety-four per cent of cephalopods are oceanic and neutrally buoyant and 84 % of these are ammoniacal. Cranchiids contribute 57% by number and an estimated 25% of the weight, and histioteuthids 26% by number and 38 % of the weight of cephalopods eaten. Three species offish and two of cephalopod have not been previously recorded in sperm whale diets. Comparison with an earlier study shows that the diet is essentially stable over a 14-year period.
Continuous Plankton Records: Annual Fluctuations of the Plankton in the Western English Channel, 1958–83
Authors: Robinson G. A. , Hunt H. G.
Published: May 2009

Surveys of the plankton at a depth of 10 m in the western English Channel have been carried out at monthly intervals from 1958 onwards using Continuous Plankton Recorders to provide data on annual fluctuations in abundance of the plankton. Interpretation of these results has been attempted by empirical associations with environmental factors (salinity, sea-surface temperature, radiation, atmospheric pressure patterns, wind speed and current strength). Principal component analysis has been used to extract the main patterns of change and correlation analysis for assessing the relationship between the plankton and the environmental factors. There are complex relationships between the plankton and all environmental factors, supporting previous conclusions that the long-term changes are mediated through interaction between the plankton and the climate. Spectral analysis showed long-term trends and shorter cycles of six and three to four years in both the biological and physical elements, indicating that changes in the western Channel are responding to changes in climate over a much wider area
The Biology of the Deep-Sea Species of Mysidacea (Crustacea) of the Rockall Trough
Authors: Mauchline J.
Published: May 2009

The mysid fauna of the Rockall Trough consists of more than 35 species partitioned between the pelagic water column and the bentho-pelagic environment. The pelagic mysids are dominated byEucopia grimaldii, E. unguiculataandBoreomysis microps.The benthopelagic mysids, in a transect from 400 to 2900 m depth, are divided into four faunal associations.Pseudomma affinedominates the 400–800 m depth range; the impinging bathypelagicGnathophausia zoeaand the benthopelagicBoreomysis widensdominate the 800–1300 m range;Michthyops parvaandParamblyops rostrataare co-dominants in the 1400–2300 m range; whileAmblyopsoides ohliniidominates the 2170–2965 m range. The benthopelagic mysid fauna is most diverse at depths below 1400 m. It is dominated by species whose geographical distribution is restricted to the North Atlantic, in contrast to the pelagic mysid fauna, which is dominated by cosmopolitan species. Notes on the breeding season, biology and population structure of several species are given.
Hatchetfishes Hold Horizontal Attitudes During Diagonal Descents
Authors: Janssen John , Harbison G. R. , Craddock J. E.
Published: May 2009

Based on analysis of videotape records, species of the genusArgyropelecusare capable of swimming diagonally downwards at considerable speeds without altering their body postures. Morphological evidence strongly suggests that they are able to swim diagonally upwards in a similar way. Their distinctive hatchetlike profile presents a streamlined airfoil in both diagonal and horizontal movements, even though the body is not tilted. Modifications of the caudal musculature probably enable all hatchetfishes (including members of the other two genera,PolyipnusandSternoptyx) to use the tail for propulsion for both diagonal and horizontal movements. The dorsal fin probably aids in diagonally downward movements and the pelvic and anal fins in diagonally upward movements, whilst the pectoral fins serve as stabilizers for these movements, and as an axis of rotation for striking at prey. The seemingly ungainly shape of the hatchetfish is the result of achieving a streamlined, fish-like shape for horizontal and diagonal movements without tilting of the body, presumably in order to maintain an effective camouflage in midwater.
A Large-Volume Pump System for Studies of the Vertical Distribution of Fish Larvae Under Open Sea Conditions
Authors: Harris R. P. , Fortier L. , Young R. K.
Published: May 2009

A large-volume pump system (2.8 m3 min-1) for sampling fish larvae under open-sea conditions is described. Comparative efficiency trials by day and night showed that the pump was generally as efficient, or in some cases more efficient, in capturing larvae than vertically hauled 200 μm WP2 nets, though there was some evidence of visual avoidance by particular larval size classes during daylight. The pump system is particularly appropriate for investigating fine-scale vertical aggregations (1–10 m3) of larval fish in relation to the distribution of their food organisms.

INTRODUCTION

Studies of the distribution of larval fish and their food organisms in relation to physical structure in the water column require sampling techniques capable of resolving fine-scale temporal and spatial distributions. As an alternative to conventional nets, large-volume pumps, sampling at rates in excess of 1 m3 min-1; provide such a capability. Major benefits of using large pumps in addition to temporal and spatial resolution are that a wide range of sizes of plankton including larval fish can be sampled simultaneously in relation to physical and chemical properties of the water column; there is reliable control of the volume of sample filtered and problems of clogging of towed nets are avoided; long series of sequential samples can be taken in studies of small-scale distribution; and instrumentation with in situ CTD and fluorometers at the intake enables real-time control of sampling in relation to physical structure.

General engineering considerations for using such pumps have been reviewed in detail by Miller & Judkins (1981), and a particular area of application has been in power-plant entrainment studies in shallow fresh water (Portner & Rhode, 1977; Bowles & Merriner, 1978; Gale & Mohr, 1978; Ney & Schumacher, 1978; Elder et al. 1979; Leithiser, Ehrlich & Thum, 1979; Cada & Loar, 1982).
A Descriptive Ecology of Eledone Cirrhosa (Mollusca: Cephalopoda) in Scottish Waters
Authors: Boyle P.R.
Published: May 2009

A survey of the ecology of the octopus Eledone cirrhosa in Scottish waters is compiled from structured interviews with fishermen, records of occurrence in traps (for lobster and crab), and a research vessel survey. This species is widespread and common throughout the inshore waters covered by fishing activity (shoreline- 140 m) on bottom types ranging through rock, stones, sand and mud. It is caught in all months of the year but is especially common inshore in the summer (July-September) and further offshore on trawling grounds in October-December. The octopus is a normal and regular predator of large Crustacea (Hotnarus, Nephrops, Cancer) caught in commercial traps but gut contents yield little identifiable dietary remains.
New Records of Tubeworms Established in British Harbours
Authors: Thorp C. H. , Jones-Knight Phyllis , Jones-Knight E. W.
Published: May 2009

Populations of the spirorbid Pileolaria berkeleyana ( = P. rosepigmentata) are recorded in harbours at Plymouth, Falmouth and Portsmouth and of three similarly abundant serpulids, Filogranula calyculata and Metavermilia multicristata at Abereiddy and Vermiliopsis striaticeps at Falmouth. Ship-borne introductions may well have occurred but the Abereiddy serpulids have more probably come from undiscovered populations nearby, in areas too rocky and deep for easy sampling.

INTRODUCTION

Three apparently exotic species of tubeworms, a spirorbid and two serpulids, have been established for at least five years in aquarium tanks at the Portsmouth Polytechnic Marine Laboratory. The tanks receive a continuous flow of unfiltered sea water, which is pumped from Langstone Harbour via a header tank, with little if any change in temperature. They contain many slate slabs from a flooded quarry (at Abereiddy, in South Wales), which had been opened to the sea in 1932 and is used as a harbour for small boats. The most recent transfer of slates to Portsmouth was in 1972. The slates were brought in because they bore populations of a native spirorbid (Thorp, 1975), but the associated fauna was not closely studied at that time because a general account of Abereiddy quarry and its fauna was being prepared by Hiscock & Hoare (1975).

The exotic serpulids occurred particularly on the undersides of the slates, but had not been noted by Hiscock & Hoare, nor in any other British fauna list. They also occurred on the underside of a disused heater/cooler plate supporting the slates in one of the tanks, which indicated that they had been breeding in that tank.
The Ecology of Idotea Species (Isopoda) and Gammarus Locusta (Amphipoda) on Surface Driftweed in Galway Bay (West of Ireland)
Authors: Tullyand O. , Céidigh P. Ó
Published: May 2009

Four species of Idotea and Gammarus locusta were associated with drifting seaweed. In all species and throughout the year juveniles predominated. Peak numbers occurred in summer when most seaweed was collected, but /. emarginata and /. baltica were common also in spring and autumn. All species also occurred freely swimming at the surface. No diel vertical migration was detected.

Drifting alga provides only a temporary and unstable habitat for associated species but is important as a medium for habitat expansion and as a refuge from predators for actively dispersing juveniles.

Breeding activity in all species peaked during the summer but continued at a low level for most of the year.
Larval Development of Deep-Sea Gastropods (Prosobranchia: Neogastropoda) From The Rockall Trough
Authors: Colman J. G. , Tyler P. A. , Gage J. D.
Published: May 2009

The larval shell morphology of 14 species of neogastropod from the Rockall Trough, N.E. Atlantic has been examined using scanning electron microscopy. Mode of development has been interpreted from protoconch size and morphological features, from the ratio of protoconch diameter to number of larval whorls and by comparisons with confamilial or congeneric shallow-water neogastropods in which development is known. Eight species have non-planktotrophic and 6 have planktotrophic development. Food availability and feeding strategy are important factors in the development of the two different reproductive strategies in the deep sea.
The Age of Fishes and the Rate at which they Grow
Authors: Allen E. J.
Published: May 2009

At a time like the present, when the Empire we have inherited stands facing a crisis of its fate, when indeed the whole structure of civilization as we know it has seemed to sway, when that which generations of earnest thinkers have dreamt of as the progress of the race recoils before the forces it has itself unchained, it is difficult to restrain a feeling of incongruity in discussing any subject that has no obvious bearing on the greater problems of the hour. But I am convinced that we are following the right course in carrying on, with such help as remains available, the work of this Association, whose object is the advancement of Science, Literature and Art. In the short, swift cataracts of war, no less than in the gentler, steadier flow of peace, these matters of the mind have still their power.
Locomotion and visual behaviour of mid-Water crustaceans
Authors: Land Michael F.
Published: May 2009

Video recordings were made of the behaviour of hyperiid amphipods and other mid-water crustaceans in a tank lit from above with a dim VDU screen, and from behind with infra-red light. Computer-generated stimuli could be moved across the VDU screen. Amphipods swam at speeds up to 19 body lengths per second. Some(Brachyscelus, Phrosina)consistently swam inverted, rolling from side to side. Others(Platyscelus, Parapronoe)spent periods of time rotating in the water with the dorsal acute zone of the eye pointing upwards. Both behaviours are interpreted as forms of visual scanning. Different species were active at different light levels,Phronimapreferring the dimmest illumination. Three kinds of visual behaviour were seen consistently. The animals dropped from the surface as a dark square passed above them; they tracked other individuals (Hyperiids) or, in the case of Euphausiids, the stimuli on thescreen above; and they occasionally swam towards each other and collided, apparently deliberately.
The origin and recruitment of bass, Dicentrarchus labrax, larvae to nursery areas
Authors: Jennings S. , Pawson M. G.
Published: May 2009

The distribution of bass, Dicentrarchus labrax (L.), eggs taken in ichthyoplankton surveys of the Bristol channel and eastern Celtic Sea from April 1989 to May 1990 indicates that bass spawned predominantly offshore during March and April. Seventy-two bass larvae were captured by ring net and 16 by high-speed tow net during 19–27 May 1989, and 11 were captured by ring net during April and May 1990. Larvae were most abundant inshore where the water column was unstratified and less than 50 m deep.

Back-calculated egg fertilization dates were determined for 58 larvae captured in May 1989 by ring net, using estimates of temperature-dependent egg and larval development rates and counts of daily growth increments on sagittal otoliths. These dates ranged from 5 April to 10 May 1989, later than those for most young-of-the-year bass which first appeared in Welsh estuaries during June 1989. This implies that bass larvae would have been more abundant before the May sampling period, even though these catches are the largest reported from UK waters.

Bass larvae of 5–11 mm live notochord length were captured close to estuarine nursery areas, and their mean growth rate was approximately 0·2 mm per day. However, the smallest bass first arriving in the nursery areas during June, July and August were always larger than these larvae, and predominantly 15–20 mm total length. It is suggested that bass larvae hatching offshore either perish or are transported to unstratified coastal waters where they feed and remain for at least 30 days prior to their recruitment to the nurseries.
Marine Pelagic Ciliates and Their Productivity During Summer in Plymouth Coastal Waters
Authors: Pilling E. D. , Leakey R. J. G. , Burkill P. H.
Published: May 2009

The ciliate list for Plymouth waters has been extended by 14 species using modern taxonomic techniques. Ciliates were abundant in the plankton where they formed a significant food resource. Their community biomass and production was estimated to average 12 µ C 1 and 9 µ C 1 respectively during the summer. The ciliate community was dominated by a diverse assemblage of aloricate choreotrichs, suggesting a complex trophic role for this protozoan group.

Ciliate protozoans are ubiquitous and often abundant in marine waters where they are frequently considered to play an important ecological role in trophic flux and nutrient cycling within the plankton (Fenchel, 1987). In spite of this, however, their ecological role in British coastal waters is poorly understood. In Plymouth waters, for instance, there has been only one previous study of marine pelagic Protozoa (Lackey & Lackey, 1963), despite the presence of a marine laboratory in the region for over 100 years. As the study by Lackey & Lackey (1963) focused solely upon the taxonomy of local protists, the ecological role of protozoans in Plymouth waters is unknown. To redress this anomaly the present pilot study was undertaken in Plymouth waters with the following objectives: to identify the dominant ciliates from this region using techniques unavailable to Lackey & Lackey (1963), to quantify ciliate abundance and cell sizes, and to estimate their biomass and production.

Triplicate water samples were collected, using a 3-litre water bottle, from surface waters at each of four stations along a 20-km transect between Plymouth Sound (50°21'N 04°09'W) and the Eddystone Rock (50°ll'N 04°16'W) during June, July and August 1988.
Patterns of variation in the dry body weight of Calanus finmarchicus in copepodite Stage V during autumn and winter in the Firth of Clyde
Authors: Grigg H. , Holmes L. J. , Bardwell S. J.
Published: May 2009

Variations in dry body weight in the Stage V copepodite, associated with the development of the winter generation of Calanus finmarchicus (Gunnerus) in the Firth of Clyde each year were observed from 1978 to 1982, during early October and the middle of January.

The Stage V copepodite was dimorphic with respect to body size. Body weights of freeze-dried specimens were measured and form was distinguished using the prosome length. Allometric relationships of the dry weight to length in the two forms were similar, and stable between autumn and winter. From the mean of estimates for all collections, dry body weights of individual Stage V copepodites were proportional to the cube, approximately, of prosome lengths. Proportional coefficients were seasonally variable, but on all occasions these were greater for the large than the small form. Variations in dry weight were directly associated with the distinction between forms in body volume.

Collections from October and January encompassed the period between the end of maximal Copepodite V recruitment and the onset of adult recruitment to the winter generation. Over this period, however, the dry body weight in all years decreased relative to length in Copepodite Stage V. This decrease, on average, was by 17% and 23% in the large and small forms respectively. Monthly collections from one population were used to examine these patterns in relation to the development of gonads. Stage V copepodites of both forms were increasing in dry weight during October, but from November were losing weight continuously. Maturation in the majority of these individuals was restrained throughout autumn, abruptly accelerating in winter.
On the Reproduction and Development of the Conger
Authors: Cunningham J. T.
Published: May 2009

Before the Laboratory of the Association was built, it had often been observed in other aquaria that female conger after living for some time in captivity, feeding regularly and voraciously, and growing with considerable rapidity, passed into a swollen and apparently gravid condition and then died. Such conger when dissected after death were invariably found to contain enormously developed ovaries or roes, which entirely filled up and distended the abdominal cavity, and pressed the intestine and other abdominal organs into as small a space as possible. The following are the principal records of cases in which this has been observed.
A List of the Nemertines of Plymouth Sound
Authors: Riches T. H.
Published: May 2009

The present list, the result of observations made at intervals in the course of last year, was undertaken with the view of determining for embryological purposes the resources of the Sound with regard to this group. It includes the species obtained during a great part of the year 1892.
The Post-Larval Stage of Arenicola marina
Authors: Blaxland Benham Wm.
Published: May 2009

By “post-larval stage” I wish to indicate that stage in the developmental history of Arenicola at which the full adult number of somites has appeared, and the body is already distinguishable into (a) an anterior chætigerous region, and (b) a posterior achætous region or tail, but in which the gills are not yet completely formed or have not yet even made their appearance.
Young Stages of Zeugopterus punctatus
Authors: Cunningham J. T.
Published: May 2009

On May 4th of the current year a number of small Pleuronectids were captured by the hand in a pool left by the ebb tide at Plymouth Breakwater, and brought to me alive. Two of them were very transparent, and, from their habit of lying on the right side when at rest, evidently sinistral forms. One of them was almost perfectly symmetrical; while in the other the torsion of the facial region and eyes had commenced. The pigmentation had the form of interrupted transverse bands, which were most conspicuous on the dorsal and ventral fins; on the dorsal fin seven bands were indicated. The terminal portion of the original trunk, containing the notochord, was seen at the upper edge of the caudal fin. The neurochord was covered with pigment, forming a very distinct band, situated, however, not in the skin, but in the connective tissue surrounding the neurochord or spinal cord. The mouth was large, and the snout upturned. The pectoral fin was large, the pelvic small. But the most important characteristic was the presence of two straight spines projecting laterally from the auditory region. These have been called otocystic spines by Prof. McIntosh, but I think they would be more appropriately described as periotic spines, as they are evidently projections of the periotic cartilage or bone; to which particular bones of the periotic region they belong has not been determined. Mr. Holt cut sections of the spines in situ, and found that they consisted of a knob of periotic cartilage passing into a mass of undifferentiated cells, the whole forming the core of a dermal spine consisting of hyaline ossified tissue. In my specimens I observed a third spine, much smaller, situated in the region of the frontal bone, behind and above the eye; it was visible in both the stages.
Engulfment of Prochloron cells by cells of the ascidian, Lissoclinum
Authors: Cox Guy
Published: May 2009

Serial-section electron micrographs have been obtained of the phagocytosis of Prochloron cells by amoebocytes of the ascidian Lissoclinum voeltzkowi (Michaelsen). This may answer the hitherto puzzling question of how the host tunicate benefits from photosynthetic symbionts situated in an excurrent water flow.
Biology of littoral blenniid fishes on the coast of south-west England
Authors: Milton P.
Published: May 2009

Observations in the field, and in the laboratory, of littoral fishes of south-west England during the period 1978–80 have shown that the three blenniid species found with any frequency on the shore constitute an important link in food chains. The occurrence, age, habitat and diet ofBlennius (Lipophrys) pholisL.,Coryphoblennius galeritaL., andParablennius gattorugineBrunnich have been considered; B.pholiswas by far the most common of the three, with very fewP. gattoruginebeing found intertidally. Of the latter, only age groups 0, 1 and 2 were represented in the littoral populations, whereas in the truly littoral species age groups 0–10 were found forB. pholisand 0–6 forC. galerita.Measurements of growth rates for the three species have been compared with growth rates ofB. pholisandC. galeritaat other sites, and a similar treatment has been afforded to dietary constituents. A discussion of the possible competition for food and refuge between the three species, and with other littoral teleosts, concludes that highly efficient partitioning of resources reduces competition to a minimum, with the exception of abundant food items which are (in any case) probably underexploited.
The retial system of the locomotor muscles in the thresher shark
Authors: Bone Q. , Chubb A. D.
Published: May 2009

The red muscle of the thresher-shark myotome is internalized and supplied by a simple rete in connexion with lateral vessels. It is probable that the system enables the fish to be warm-bodied.

INTRODUCTION

Warm-bodied sharks were first described by Carey & Teal (1969); subsequent observations by Carey and his colleagues (Carey et al. 1971) and by Carey (1982) showed that five lamnid species were able to maintain body temperatures 5–10 °C above the ambient water. All of these possess more or less elaborate retia linking a red muscle mass lying internally in the myotomes with the systemic circulation. In cold-bodied sharks, the red muscle lies superficially, just under the skin, and retia are absent. A sixth lamnid species, the big-eye thresher shark (Alopias superciliosus) may be warm-bodied; it has a simple muscle retial system (Carey et al. 1971) which has not been described in detail. The chance capture of a common thresher shark (A. vulpinus) enabled this short description of the retial system in this species.
Observations on the temperature and salinity relations of Lasaea rubra
Authors: Davenport John , Beard Jane B.
Published: May 2009

In direct-transfer temperature tolerance experiments, Lasaea rubra was found to have a median lethal low temperature of – 3.5°C and a median lethal high temperature of + 39°C. If introduced to temperatures slowly, survival at extreme temperatures was improved, particularly at freezing temperatures; > 92°0 of animals survived at – 10 °C and + 40 °C if introduction from a holding temperature of + 18 °C took place over at least 1 h.

Lasaea rubra are active at salinities between 15 and 60‰, indicating considerable tolerance of changes in body fluid osmolarity. In week-long exposure experiments more than 50 % of animals survived all salinities from 0 to 150‰; tight shell valve closure was maintained at extreme salinities.

When exposed to declining salinity, Lasaea rubra progressively isolates its tissues from the environment as salinities fall below 18–20‰, and maintains shell valve closure below 8‰. These responses are symmetrically reversed in response to rising salinity.

Salinity discrimination in Lasaea rubra is based upon sensing of external osmolarity, not external ionic concentrations.
Effect of a chelating agent (EDTA) on zinc uptake and regulation by Palaemon elegans (Crustacea: Decapoda)
Authors: Nugegoda D. , Rainbow P. S.
Published: May 2009

The littoral prawn Palaetnon elegans Rathke regulates the body concentration of zinc at higher external zinc concentrations in the presence of EDTA. The dissolved zinc concentration in artificial sea water corresponding to the threshold of regulation breakdown changed from ca. 100 μg Zn 1-1 (ca. 1.53 μmol Zn 1-1) without EDTA, to ca. 316 μg Zn 1-1 (ca. 4.8 μmo1 Zn 1-1) in the presence of 8.6μmol EDTA 1-1 at 10 °C. The regulated body Zn concentration remained unchanged at 77–79 μg Zn g-1 dry wt with or without EDTA. Increased levels of EDTA in the medium decreased the rate of uptake of labelled zinc by P. elegans. The presence of 3 μmol EDTA 1-1 decreased the mean Zn uptake rate of prawns in 100 fig Zn 1-1 (ca. 1.53 μmol Zn 1-1) from 2.9 to 0.25% of total body Zn g-1 day"1 at 10 °C. The increased ability of P. elegans to regulate zinc in the presence of EDTA may be explained by the reduced bioavailability of the zinc-EDTA complex for uptake. There is marked individual variation in the rate of uptake of labelled zinc in prawns, even in the presence of the same concentration of zinc or zinc-EDTA.
Ecology and demography of a population of Anseropoda placenta (Echinodermata: Asteroidea) in the Bay of Brest, Brittany
Authors: Guillou M. , Diop M.
Published: May 2009

The starfish Anseropoda placenta (Pennant) is abundant in the gravelly sands of the Bay of Brest (Finistere, France). The size, distribution and density of this animal were evaluated along a transect perpendicular to the River Aulne in the southern part of the Bay. The spawning phases, the recruitment and growth processes were defined. When the entire population was considered, three plurimodal year classes were visible from the length frequency histograms. Year-class segregations were observed. Their density varied in space and time in a manner which suggests a pattern of migration from the southern part of the transect towards the northern part. Juveniles were recruited mainly during the autumn on the gravelly bottom of the southern shallow part. By late winter, they had migrated to the deeper parts of the channel. Feeding preferences do not seem to be the main factor controlling these migrations which are discussed in relation to environmental factors and the intra- and inter-specific competition.
Notes on the behaviour of Pectinaria koreni
Authors: Nicolaidou Artemis
Published: May 2009

The paper presents preliminary data on the response of Pectinaria koreni to light and on the effect of light and temperature on its rate of sediment reworking. Pectinaria at the ‘settling in’ stage reacted to light by burying themselves completely under the sediment. There was indication that vertical movement of Pectinaria in the sediment followed a diurnal rhythm probably associated with feeding activity. Pectinaria was most active at higher temperatures and in the dark. At 7 °C the rate of sediment reworking was significantly less than that at 10 and 15 °C and was not affected by light. At 10 and 15 °C the amount of sediment reworked in the dark was significantly greater than that reworked in the light.
Mechanisms of trace metal accumulation in the polychaeteNeanthes arenaceodentata
Authors: Mason Andrew Z. , Jenkins Kenneth D. , Sullivan Patricia A.
Published: May 2009

The mechanisms of accumulation of zinc and cadmium by the marine polychaetous annelidNeanthes arenaceodentata(Moore) have been studied. Animals have been exposed to EDTA chelate buffered sea water containing65Zn and109Cd. The calculated free ion activities of the zinc and cadmium in the sea water were 10-8.13M and 10-7.65M, respectively. Uptake occurs from the free ionic pool of metal and EDTA and EDTAmetal complexes are largely excluded from the animal. In unfed animals, the metals accumulate linearly with time at a rate which decreases when the temperature is reduced but increases in the presence of metabolic inhibitors. Experiments using [14C]EDTA as an extracellular marker indicate that the observed increase in accumulation caused by the inhibitors is at least partially due to media entering extracellular anatomical compartments such as the coelom and lumen of the gut which are normally isolated from the seawater by cilia or sphincters.
Long-term variability in North Sea zooplankton off the Northumberland coast: productivity of small copepods and analysis of trophic interactions
Authors: Roff John C. , Middlebrook Ken , Evans Frank
Published: May 2009

All groups of meso- and macro-zooplankton in the North Sea off Northumberland, at a depth of 53 m, were studied during a 15-year period (1969–83); copepod productivity was estimated from biomass and growth rates. Phytoplankton were seasonally bi-modal with peaks in April and August–October; copepods were uni-modal peaking in June–July. The predatory zooplankters: larval fish, decapods, ctenophores, medusae (the summer-autumn predators) peaked between May and September, while chaetognaths and euphausiids (the winter predators) peaked in December–January. Copepods and the summer-autumn predators were seasonally and inter-annually positively correlated, and declined in abundance from 1974 to 1980. Euphausiids and chaetognaths on the contrary increased in abundance during these years, and were seasonally and inter-annually negatively correlated to the copepods. The mean annual abundance of copepods was positively related to the previous winter's minimum, and inversely related to the abundance of chaetognaths and euphausiids. Annual copepod productivity averaged 1260 kJ m-2 year-1, and showed no relationship to other groups of plankton.