Diel feeding pattern of red mullet in the Hisarönü Bay was studied from samples collected by bottom trawl during a 24-h period in the summer of 1997. Feeding activity of red mullet commenced at dawn and reached its maximum value at noon. During the period between noon to early evening, feeding intensity slowed down and then showed a small increase towards sunset. After sunset, the feeding activity nearly stopped and fish with empty stomachs increased. At night almost all stomachs were empty. Polychaetes, decapods, bivalves and amphipods were the major prey groups in the diet of red mullet and no significant diel variations were observed in the relative importance of these groups.

An examination of the postlarvae of the goby Lebetus Winther collected in the neighbourhood of Plymouth shows that there are two forms, separable on degree of development of the fins, meristic characters and body proportions. The differences are sufficient to indicate that there must be two species whose identity can only be made certain by rearing, since the original two species L. orca (Collett) and L. scorpioides (Collett) have recently been regarded as one species showing sexual dimorphism.

Between March 1933 and June 19391 a series of vertical hauls with a plankton net has been made at a line of six stations 12 miles apart, the first lying off Flamborough Head and the last on the south-west patch of the Dogger Bank. This line was usually visited at monthly intervals, the net used being of the Hensen type fitted with bolting silk of 60 meshes to the inch and hauled to the surface by the counter-weight device introduced by Buchanan-Wollaston (1911). Hensen (1887) worked out a filtration coefficient for his net, and when this was applied to the dimensions of the one in use and the depth through which the vertical hauls were made, it was possible to express the catch in numbers per cubic metre of sea water. It was also possible to give the individual catches by weight, and it may not be without interest to observe, before passing on to deal with numbers, that the dry weights taken in 1936 varied between 0.2600 g. per m.3 in August and 0.0015 in February.

Although the net method of estimating plankton has often been decried as unreliable, Hensen net results have always given a consistent picture of relative plankton densities in the North Sea. Confidence arising from this consistency has not been lessened by a comparison of the net and sedimentation methods which has been made in respect of the May 1938 samples.

The sedimentation method consists in counting the entire deposit of microplankton which has settled on the floor of a glass cell containing a known volume of sea water.

The first record of a bivalve-inhabiting hydrozoan Eugymnanthea inquilina was found in Thermaikos Gulf, north Aegean Sea, eastern Mediterranean Sea, associated with Mytilus galloprovincialis. Analyses of biometric data point the same biological differences between the Mediterranean and the Japanese Eugymnanthea, as reported by previous researchers.

A light and electron microscopic study of the enterocytes and gut-associated lymphoid tissue (G ALT) of the flounder Platichthys flesus showed regional differences in the structure of the epithelial cells. Epithelial villi decreased in height and spatial complexity, but increased in overall thickness in the posterior intestine. There were no specialized cells comparable with mammalian M cells. Periodic acid Schiff (PAS) activity increased in the enterocytes and goblet cells in the anterior intestine where alkaline phosphatase activity was most pronounced in enterocytes. Adjacent cells were joined by tight junctions.

Gut-associated lymphoid tissue was composed of isolated leucocytes in the epithelium and lamina propria with no accumulations. Numbers of intra-epithelial leucocytes were not statistically different in the various regions of the intestine. Five leucocyte types were distinguished among the gut-associated lymphoid tissue although lymphocytes and granulocytes were the most common. Granulocytes were positive for the Romanowsky stains with PAS/Alcian blue positive granules. Blast cells similar to large lymphocytes were unevenly distributed through the different regions of the intestine. Plasma cells were more numerous in the epithelium than in the lamina propria. Macrophages were rarely detected.

Phagocytes of the starfishes Asterias rubens L., and Marthasterias ghcialis (L.) (Echinodermata: Asteroidea) phagocytose allogeneic and xenogeneic phagocytes in vivo, but form non-reactive aggregates or syncytia in vitro. The coelomocytes of the sea urchins Echinus esculentus (Mortensen) and Psammechimts miliaris (Gmelin), (Echinodermata: Echinoidea) also form aggregates or syncytia with allogeneic and xenogeneic cells in vitro. Mutual cy totoxicity could not be demonstrated either by enzyme-release or by decrease in numbers of viable cells in cultures of mixed origin as compared with autogeneic controls. The factors which may govern cell recognition and behaviour are discussed.

The subunit composition of haemocyanin (Hc) from the semiterrestrial beachflea Orchestia gammarellus exhibited less heterogeneity and less (qualitative) between-individual variation than most decapod Hcs. While between-population variation was detected, no clear trends in Hc subunit composition from four populations along a salinity gradient were observed. Salinity had no detectable effect on Hc subunit composition or HcO2 binding in the laboratory. The degree of phenotypic variation in laboratory-held beachfleas was less than that displayed by any of the natural populations examined. Furthermore, examination of the O2 binding characteristics of five of the most common Hc phenotypes showed that each phenotype had the same O2 binding properties. Differences in Hc subunit composition between individuals and between populations may exist, but it should not be automatically assumed that such variation will have consequences for intrinsic Hc O2 binding properties.

INTRODUCTION

Lincoln (1979) stated that ‘four species (of Gammaropsis Liljeborg) are reported from the British Isles, Gammaropsis maculata (Johnston), G. palmata (Stebbing & Robertson), G. nitida (Stimpson) and G. sophiae (Boeck)’. In fact, six species of Gammaropsis have been reported from the British Isles in the literature, the records of G. lobatus (Chevreux) (Spooner, i960) and G. melanops (Sars) (Jones, 1948) having apparently been overlooked by Lincoln (1979). Spooner's (1960) material is apparently no longer extant, but the material attributed to G. melanops by Jones (1948) has been re-examined by us and found to be referable to G. lobata. Recent collections of G. lobata from the west coast of Ireland confirm a rather wide distribution of this species in the southwest of these islands.

Five species of Gammaropsis are therefore now known from these islands, and G. melanops can, at least for the present, be deleted from the British and Irish list of species.

Lincoln (1979) was unable to examine any British material of G. sophiae, everything labelled as such, in the material examined by him (including the Norman collection at the B.M.N.H.)* being referable to G. nitida. He therefore figured the species from West African material. G. sophiae is quite widespread along the southwest coast of Ireland and since it differs somewhat from the material described by Lincoln (1979) it is figured herein from the Celtic Sea.

Krapp-Schickel & Myers (1979) reviewed the Mediterranean species of Gammaropsis and segregated the species into two groups, group ‘A’ species characterized by the possession of a toothed urosome, toothed coxa 1 and long acute epistome, and group ‘B ‘ species characterized by having a smooth urosome, smooth coxa 1 and short epistome.

Oncholaimus cobbi was described from the Brazilian coast. The area studied, Coroa Grande, is located in Sepetiba Bay, State of Rio de Janeiro, Brazil. Sampling was carried out monthly, from May 1998 through April 1999. Most of the population was represented by adults, of which non-ovigerous females were the most abundant category. The species reached its highest population density during the warmest months, and the highest densities of males and ovigerous females were seen in February 1999.

Previous studies on the significance of dissolved organic compounds in the nutrition of the smaller species of the phylum Pogonophora (Little & Gupta, 1968, 1969; Southward & Southward, 1968, 1970) were handicapped by lack of information about the levels of free amino acids in the tissues. In this brief note we give preliminary results for four species, using a modification of the technique described by Clark (1964, 1968, 1973) to estimate the amino acids in extracts of the whole body.

1. The yellow colours of the hydroids include at least two groups, the carotinoids found in the Antennulariidæ and Haliciidæ and the flavone-like pigments that occur in the Sertulariidæ. From the literature a third group, the uradines, may be added.

2. The flavone pigments and their relatives are all water soluble and are thus distinguished from the carotinoids which are not water soluble, but may be dissolved in the usual fat solvents.

3. In the Sertulariidæ studied, a graded series of chromatophore groups and pigments was found which ranged from the colourless species Sertularia argentea Ellis and Solander, through the yellow of Sertularella gayi Lamaroux and S. polyzonias Linnæus, to the orange-brown of Thuiaria articulata Pallas. The brown of Sertularia pumila is probably also a flavone derivative.

4. The flavones and related pigments occur extensively in the plant kingdom. It is probable that the flavone-like pigments found in the Sertulariidæ are of plant origin.

The abundance of Calanus finmarchicus is known to have fallen between the present and the late 1950s in north-eastern Atlantic shelf waters. Further west in deeper water, however, long-term abundance of the copepod has risen.

The effect of light intensity on the course of embryonic development of squid (Heterololigo bleekeri) was examined. Heterololigo bleekeri embryos at an early stage were incubated in the egg cases under six to seven gradients of light intensities which varied from constant darkness to intensive light >1000 lx (12L:12D for all experimental groups except for the constant darkness group). Duration of hatching in every experimental group ranged from seven to 15 days with a peak for ≈30–50% of total number of hatchlings. However, there were no particular relationships between light intensities and duration of embryonic development, duration of hatching, number of hatchlings at hatching peak, and body size of hatchlings. In all groups, body size of hatchlings increased up to seven days post-hatching and thereafter did not change remarkably. Just after hatching, strongly positive photo taxis was observed for H. bleekeri

A survey was carried out from April 1998 to June 2000 to study the structure and the secondary production of the population of Heteromastus filiformis in the Loire estuary. Each month, samples were collected in the intertidal zone of Mindin harbour. The length of the thorax (L12) was correlated with the fresh weight (FW) with the relation FW=1·49848 L12–3·62804 (r=0·92). In 1999, the mean density was 2184 ind m−2 with a minimum of 1104 ind m−2 in December and a maximum of 3328 ind m−2 in March. The mean annual biomass was 15·4 g m−2 with a minimum of 2·6 g m−2 in December and a maximum of 28·2 g m−2 in March. Most of the histograms of size–frequency are unimodal and could be considered a single cohort except in May and November/December 1999. The abundance and biomass of the population of H. filiformis decreased during summer and winter which are mortality periods and increase during spring and autumn which are recruitment periods for the population. The life time for a cohort was from six to nine months depending on the recruitment period and on the inter-annual variations. The secondary production was estimated by the method of Crisp (1971). The annual secondary production in 1999 was P=104·3 g m−2 with B¯=15·4 g m−2 and P:B¯=6·8. The quantity of sediment reworked by H. filiformis is about 116 l m−2 y−1 or 65 kg m−2 y−1 which is approximately a deep-sediment layer of 12 cm transported to the surface annually.

Lake Vouliagmeni (Attica, Greece) is a lagoon of great scientific interest due to its endemic fauna, widely used for recreational activities. Understanding the dynamics of this peculiar ecosystem is essential for its conservation. An ecological survey of the benthic communities was carried out, in both spatial and temporal scales. Material was collected with SCUBA diving, by taking off samples from the principal habitats of the lagoon, i.e. meadows, soft and hard substrata. The identification of the collected 61,975 living specimens revealed the presence of 12 floral and 20 faunal species. Multivariate analyses separated the sampling sites according to the four different habitats of the lagoon, whereas no temporal patterns came up. Micrograzers were the dominant trophic group, followed by deposit feeders regardless of the habitat studied. Lake Vouliagmeni is among the less diverse Mediterranean lagoons, mostly due to its isolation from the sea that hinders the entrance of marine species.

The radular activity of dogwhelks, Nucella lapillus, drilling mussels, Mytilus edulis, was monitored by piezoelectric transducers and recorded by an automatic digital system. In this way, for the first time, the drilling behaviour of dogwhelks was analysed in detail. Radular activity was similar to that previously recorded for limpets, each radular stroke (rasp) being formed by a sequence of 1–8 unit events, each probably corresponding to the application of one row of radular teeth on the substratum. During drilling, radular rasping followed a consistent pattern, each bout of radular rasping (lasting about 6–8 min) being followed by a period of radular inactivity (lasting about 35 min), when chemical dissolution is probably applied. The periodicity with which rasping was applied decreased during the drilling sequence (from about 25 min in the first quarter of the drilling process to about 40 min in the last quarter), together with a decrease in the rasping rate, i.e. number of radular rasps per min (from about 12 to about five rasps per min). Accordingly, the total number of radular rasps recorded during the first quarter of the drilling time was higher than during the other quarters (from about 3000 to about 500 rasps). The role of the radula in shell penetration was therefore rather extensive, accounting, during the first quarter of the process, for about 34% of drilling time. The results are discussed in relation to studies of chemical dissolution and mussel shell ultrastructure.

Brazilian mangroves have ecological and economic importance, with molluscs, crustaceans and polychaetes being diverse and common faunal groups. The present study characterizes the macrofauna associated with logs from two mangrove forests in Pará State, northern Brazil, sampled in September, January and April, between 2008 and 2010, at three different distances from a tidal channel (2, 10, 20 m). In each forest, five logs (diameter/length: 10/40 cm) were randomly selected at each distance, totalling 15 logs per sampling date. The macrofauna was removed, counted and identified. Three-way analysis of variance was used to compare mean numbers of individuals, numbers of taxa and Berger–Parker dominance per log, between forests and among sampling dates and distances from the tidal channel. Non-metric multidimensional scaling and permutational multivariate analyses of variance were used to investigate macrofaunal structure in relation to the three factors. A total of 5437 individuals from both estuarine and terrestrial faunas was found in both forests, with 85 taxa distributed among Mollusca, Annelida, Arthropoda and Nemertea. Abundance increased from September through January to April in both mangrove forests. The most dominant species was Neoteredo reynei, representing 48% of total abundance. No significant difference in any variable was found among the two forests and between the three distances. Logs may represent a stable microhabitat for the macrofauna, with little variation in humidity, salinity or temperature, despite different distances from the tidal channel. However, macrofaunal structure varied significantly between forests and among sampling dates, probably due to seasonal differences in precipitation and salinity between both locations.

From our previous publications (Brull & Nizet, 1953; Brull, Nizet & Verney, 1953; Brull & Cuypers, 1954), it appears that the power of concentration of the aglomerular kidney of Lophius is rather low, the density of the urine being usually less than that of the plasma concentration. Most individual urinary constituents do not reach concentrations that are more than once or twice those in the plasma, magnesium being an exception

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.

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).