The chromosomes of nine species of gammarids have been studied in oocytes and embryos. There is no evidence that polyploidy has played a part in gammarid evolution. Three of the species which we have studied, Gammarus pulex (L.), Marinogammarus marinus (Leach) and M. pirloti (Sexton & Spooner) show chromosomal polymorphism. There is no evidence that this polymorphism depends on the existence of a Robertsonian ‘fragmentationfusion’ system; rather it appears to be due to the presence of supernumerary chromosomes.

Development in the genus Diopatra has been reviewed and divided into four patterns, ranging from brooding in the parental tube to presumed broadcast spawning (Paxton, 1993). While some information is available for numerous species, the identity of some is uncertain, or the information is only anecdotal. Only three species have been studied in detail. Eggs of D. cuprea are released in a jelly mass that readily dissolves in sea-water (Allen, 1959). Although natural spawning has not been observed for D. neapolitana, Cazaux (1972) was able to fertilize the eggs artificially and culture the larvae. The larvae of both species are lecithotrophic and free-swimming, indicating that they are broad-cast spawners.

Understanding the variables (biotic or abiotic) controlling coastal communities is the main goal of ecology research and it is crucial to predict how communities will evolve under the increasing pressure on coastal systems by human activities. The general aims of this study were to assess the variables affecting the distribution of the fast-growing sponge Hymeniacidon cf. perlevis, and to evaluate if physical stressful conditions have an influence in the relationship between Hymeniacidon and the sea lettuce Ulva lactuca. Specifically, the aims were to evaluate the abundance patterns of Hymeniacidon and Ulva and to assess the relationship of Ulva and physical variables on the abundance of Hymeniacidon at both intertidal and subtidal. Hymeniacidon and Ulva showed opposite abundance patterns. Hymeniacidon was more abundant in sites without Ulva, and negatively correlated with Ulva abundance at both heights. Intertidal Hymeniacidon abundance was not correlated with physical variables, but subtidal Hymeniacidon was.

We have recently assessed phenotypic and genotypic diversity within an aggregation of the intertidal beadlet anemone, Actinia equina L., located at Burniston in N. Yorkshire, on the east coast of Britain (Quicke & Brace, 1983). The study was undertaken in order to provide information relating to the role of intraspecific aggression (Bonnin, 1964; Brace & Pavey, 1978; Brace, Pavey & Quicke, 1979) in modifying the spacing of individuals. Limited work on the genus Actinia (A. tenebrosa Farquhar) has already indicated that whilst genetically dissimilar anemones display aggression towards one another, auto-genotypic aggression is minimal (Ayre, 1982), as is also the case for the clonal anemone, Anthopleura elegantissima (Brandt) (Francis, 1973a,b,1976). We therefore anticipated that aggressive interactions would promote auto-genotypic clustering, initiated by the local settlement of the asexually produced, brooded young (Carter & Thorp, 1979; Gashout & Ormond, 1979; Orr, Thorpe & Carter, 1982), and that correspondingly, genetic diversity within aggregations of anemones would be low.

The concentration of phytoplankton chlorophyll-a (chl-a) and primary production within the euphotic zone (at depths corresponding to 100, 30, 10 and 2% light) were measured in the oceanic region of the Oyashio Water, the north-western Pacific, in spring of 1993, 1994 and 1995. The chl-a concentrations ranged from 0.15 to 6.98 mg m−3 and the range of chl-a standing stock integrated from the surface to the 2% light depth was between 4 and 43 mg m−2. The daily primary production integrated from the surface to the 2 and 0.2% light depths was estimated to be between 94 and 1695 mg C m−2 d−1 and between 114 and 2046 mg C m−2 d−1, respectively. Phytoplankton bloom was noticed when the depths of the euphotic zone and the upper mixed layer were similar. The maximum chl-a concentration and daily primary production in the upper 0.2% light depth were comparable to those reported previously in the spring bloom in the coastal, offshore and oceanic regions of the Oyashio Water, and in the summer bloom of the Western Subarctic Gyre in the North Pacific. The magnitude of daily primary production in the phytoplankton bloom in the western subarctic North Pacific (the Oyashio Water and the Western Subarctic Gyre) was comparable with those in the eastern subarctic North Pacific and the subarctic North Atlantic. The magnitude of chl-a in the phytoplankton bloom in the western subarctic North Pacific was higher than those in the other subarctic regions. Varied contribution of large diatoms to the phytoplankton biomass, caused by different iron and silicate conditions was hypothesized to be a leading factor for variation in magnitude of the phytoplankton biomass.

Age, growth and cost of reproduction were examined for the small near-shore loliginid squid Loliolus noctiluca in Tasmanian waters, near the southern limit of its distribution. The effects of several factors on hatch size were also evaluated by comparing the statolith natal ring size (NR) from individuals collected in different locations, seasons and years. The life cycle of L. noctiluca was less than six months. July-hatched females grew faster than their May-hatched counterparts, indicating a faster growth in winter-hatched compared with autumn-hatched individuals. There was considerable variation in NRs as function of location, season, year and sex, with females displaying NRs considerably larger than males in any location and year. Immature and maturing females displayed poorer body condition than mature counterparts, suggesting that gonad growth does not affect the mantle or fin growth. A good condition was maintained also in spent individuals indicating that L. noctiluca continued to invest in somatic organs throughout the spawning period. A reproductive strategy closer to ‘multiple spawning’, than to ‘single spawning’ was proposed for this species. Loliolus noctiluca was used as a model to explore the possible effects of climate change on near-shore loliginid populations.

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

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

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

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

From November to June T. koreni colonies grow rapidly and have a high proportion of developing zooids. From July to October growth slows and reproductive activity increases.

Luminescence in Amphipholis squamata has only been observed from chemically stimulated individuals, and the present laboratory study assessed the natural expression of luminescence following interaction with co-occurring organisms. The luminescence occurred only in response to (mechanical) stimulus and ranged from weak to intense reaction depending on the contact organism. Only crustaceans triggered an intense luminescence. Brachial autotomy also occurred after prolonged interaction and the luminescence continued only from the autotomized arm, which could lure the crustacean. The study showed that A. squamata luminescence could be naturally stimulated by co-occurring organisms, and the light produced sufficiently intense to be detected.

In 1996 a sponge was found in a well studied area in the Ria of Etel, Brittany, France, that had never been recorded there before. This sponge was later described as a new species and genus, Celtodoryx girardae by Perez et al. (2006), who concluded that it is probably an invasive species. Over several years C. girardae was found to occur successively in the Gulf of Morbihan, France, and Oosterschelde estuary, Netherlands. This sponge is characterized by an extensive spatial broading and therewith it rates today among the dominant benthic megafauna in the shallow waters of the Gulf of Morbihan and Dutch inshore waters. During our recent survey of the Chinese Yellow Sea sponge fauna, we found an abundant species with close morphological similarities to C. girardae. Further taxonomic studies have revealed that both the Chinese and European sponges are in fact conspecific with Cornulum ciocalyptoides described by Burton (1935) from Posiet Bay, Sea of Japan and later recorded from other localities of the North West Pacific (e.g. Koltun, 1971; Sim & Byeon, 1989). In this paper we transfer the species of Burton from Cornulum to Celtodoryx and consequently it becomes the senior synonym of C. girardae. Furthermore, we conclude that Celtodoryx ciocalyptoides was introduced to the North East Atlantic from the North West Pacific with aquaculture of the Pacific oyster Crassostrea gigas as the probable vector. This is probably the first case recorded so far of a sponge species being transferred from one ocean to another by human activity.

INTRODUCTION

The dust cart on the Isles of Scilly did not end its service at the local tip, over the cliffs at Deep Point on the eastern side of St Mary's on 14 October 1983. Instead it floated off and continued in service as a Lagrangian drifter, indicating the residual transport of water around the islands. As a hazard to shipping its position was given out as a navigation warning and it was allegedly sighted on the western side of Scilly. The interesting oceanographic question is whether the dust cart was (or would have had it not sunk) circumnavigating the islands in a clockwise or anticlockwise sense. Accordingly this experiment has been repeated using satellite tracked Argos drifting buoys, drogued with parachutes (~ 10 m diameter), and set at depths of about 15 m. The releases showed that the residual transport was clockwise around the islands. In one instance a drogue circumnavigated the islands in about 12 h (i.e. ~ one tidal period) at an average speed of about 100 cm s−1 (Fig. 1).

The commensal polynoid Acholoë astericola (Delle Chiaje) exhibits a powerful positive response on contact with its host, Astropecten irregularis (Pennant). This response is only relatively specific, Acholoë demonstrating it to a number of starfish that do not serve as host in Plymouth waters.

All living host tissue has some attraction for the commensal; and the attractant is apparently released in quantity in the stomach of the host.

Passage of time (apparently as long as tissue remains alive) and chilling do not markedly alter the attractiveness of isolated host tissue. Temperatures above 450 C. alter or abolish its attraction.

The extreme instability of the attractant has so far made it impossible to demonstrate its presence in extracts.

Evidence is presented that the attractant is rapidly oxidized.

Experiments with the scale-worms Gattyana cirrosa (Pallas) and Lepidasthenia argus Hodgson, commensal respectively with Amphitrite johnstoni Malmgren and A. edwardsi Quatrefages, indicate that a chemotaxis to the host may be of relatively minor importance in governing the behaviour of these commensals.

Three new species of coral reef boring sponges were found in remote coral reefs from Revillagigedo Island, an archipelago that is 386 km from the continent. Cliona medinae sp. nov. is a sponge with orange-yellow papillae characterized by short almost straight spirasters. Cliona tropicalis sp. nov., is a yellow papillate sponge with a spicule complement similar to the species included in the Cliona viridis complex. However, the new species differs from the rest of the species mainly in its external morphology and by differences in the size and shape of spicules. Thoosa purpurea sp. nov. is characterized by its purple colour, and the spicular complement formed by tylostyles, two amphiaster categories, bi- tri- and tetra-radiate oxyasters and smooth or microspined centrotylote oxeas. In addition, Cliothosa tylostrongylata sp. nov. is also described from coral reefs from the southern Mexican Pacific Ocean. This is a light red species, with tylostyles and tylostrongyles as megascleres and ramose and nodulose amphiasters as microscleres. The four species were found exclusively excavating skeletons of live or dead corals of the genus Pocillopora. This study increases the number of boring sponges known from the Mexican Pacific Ocean to 22 species and it is the first study on marine sponge fauna from the Revillagigedo archipelago.

Simultaneous satellite and ship measurements have characterized the structure of temperature and nitrate concentration of the Shelf-Break Front of the Armorican and Celtic Sea in late autumn (November) 1985. A chlorophyll-a distribution associated with this feature is analysed in relation to the shelf-break frontal genesis and properties, and in relation to the seasonality of in situ concentrations of chlorophyll-a at the shelf-break/slope region, adjacent shelf and adjacent ocean near ~ 47·5°N.

This study focuses on the synchronous blooms of the coccolithophore Emiliania huxleyi and three dinoflagellates Prorocentrum micans, Ceratium furca var. furca and Ceratium fusus var. seta observed between 7 June and 11 July 2003 in the Dardanelles. An analysis of the vertical distribution of the E. huxleyi population size with respect to various environmental parameters was discussed. Additionally, inorganic nutrients and phytoplankton interactions were investigated in relation to the bloom conditions and hydrography of the Dardanelles. The algal bloom started in nearby Izmit Bay (eastern end of the Sea of Marmara) in early June, then quickly spread through the Sea of Marmara and continued until mid-July. Thermal stratification was observed between different water masses at the time of sampling. During the bloom period, cell density of E. huxleyi ranged from 3.58 × 107 to 2.55 × 108 cells l−1 in the superficial layer. Prorocentrum micans was the second most-abundant species and the cell numbers ranged from 1.0 × 106 cells l−1 to 3.3 × 106 cells l−1. Other abundant species in this area included C. furca var. furca and C. fusus var. seta.

The relative growth of the fiddler crab Uca cumulanta was studied, primarily to determine the size at the onset of sexual maturity for a mangrove population in the estuary of the Patitiba River, Paraty, Rio de Janeiro state, Brazil. The evaluation of the morphological sexual maturity of U. cumulanta was performed using the allometric technique. The relationships that most precisely indicated the size at onset of sexual maturity were carapace length (CL) vs propodus length for males and CL vs abdomen width for females. Males and females are mature at 5.25 and 4.75 mm CL, respectively. The remarkable ontogenetic changes observed in the allometric growth of the male major cheliped and the female abdomen, indicate that growth of these structures is closely connected to the timing of sexual maturity. The relative size at onset maturity obtained for this species was 0.68 and this index was compared to that seen in other species in the genus.

The abundance of gastropods characteristic of rocky shores throughout the world (Southward, 1958) has encouraged investigation of their ecology and behaviour in several areas, although studies under laboratory conditions seem to have been restricted largely to the common European species Littorina littorea and Patella vulgata. Most investigations of littorinid behaviour have concentrated upon their response to light and gravity (see Newell, 1958, for a critique of earlier work), as the most important factors, after exposure, to influence life upon the shore. Variations in salinity are also significant, however, and ecological observations make it clear that littorinids are able to withstand a considerable range of salinity (Moore, 1958; Fretter & Graham, 1962; Newell, 1964; Green, 1968). But ecological studies alone do not necessarily reveal whether this capacity is to resist an adverse environment by a period of inactivity or, more particularly, to retain activity within a wide salinity range; nor do they show how far the potentialities of particular populations are related to the conditions under which they actually live. Examination of this aspect has been undertaken with L.littorea on the Atlantic coast of Canada (Gowanloch & Hayes, 1927) and with L.knysnaensis Philippi and other prosobranchs in False Bay, South Africa (Broekhuysen, 1940). However, these studies were restricted to determination of limiting salinities, without consideration of the extent to which activity occurred within the range of tolerance of the species concerned. Investigation of salinity tolerances in L.littorea is also of some general interest since, as pointed out by Newell (1958), the behaviour pattern of this species is probably fairly typical of the more mobile intertidal invertebrates.

Histochemical techniques were used to investigate the possible role of the buccooesophageal glands in the blue mussel, Mytilus edulis L. (Mollusca: Bivalvia). No activity was observed for any of the eight major digestive enzymes tested; however, the glands contained large amounts of both neutral and acid mucopolysaccharides. These results confirm the importance of mucus in the ingestive process in M. edulis, and do not support the hypothesis of ingestion of particles suspended in water alone.

Until recently it was thought that the Bivalvia were the only class of molluscs in which some type of secretory gland of extracellular digestive function in the bucco-oesophageal region was totally absent (Table 1). However, in a study of the mode of particle ingestion in five species of suspension-feeding bivalves, an extensive glandular complex was reported in the bucco-oesophageal region of Mytilus edulis L. only (Beninger et al., 1991). Although these glands were observed to liberate secretions into the oesophageal lumen, it was not known whether they performed any digestive function.

The genus Heterogorgia is reported for the first time from the shallow waters of the Galápagos Archipelago, and a new species found in the southern islands is described. The new species is distinguished from the other species of the genus described thus far by having thick branches with large, densely packed calyces, being mostly unbranched, and having larger sclerites. The occurrence of Heterogorgia verrucosa is also reported.

Assessment of spawning survival for female capelin Mallotus villosus (Pisces: Osmeriformes) greater than 12 cm in length was made in the autumn of 1995–1997 comparing a histological technique with existing methods. An intensive macroscopic visual assessment of selected samples from 1995, 1996 and 1997 revealed that 10, 20 and 40% of the females were recovering from spawning respectively each year. Histological assessments of the same fish revealed that 20% in 1995, and nearly 60% of the fish in 1996 and 1997 showed physiological evidence of previous spawning. The proportion of recovering spawners increased with both length and age of the fish. One sample from the Northwest Atlantic Fisheries Organization area of 2J during October 1997 contained nearly 90% recovering fish. The potential impact of the fishery in light of the variability in post-spawning survival of the iteroparous female capelin is discussed.

Mobile lice levels of two species of sea lice, Lepeophtheirus salmonis and Caligus elongatus, were examined on two samples of Atlantic salmon from the west coast of Ireland. The samples examined were taken two weeks apart from salmon caught by drift net in June 2003 at two different locations off the west coast of Ireland, one in the north-west and one in the west. Both samples of salmon caught were comparable in terms of numbers of total lice counted. No significant differences in male, female and ovigerous L. salmonis levels between the two samples were recorded, however, a significant difference was recorded between juvenile L. salmonis levels. Morphometric comparisons of male and ovigerous L. salmonis examined for each of the two salmon samples examined revealed some differences. There was a significant difference in male L. salmonis in terms of cephalothorax length between the samples. In the females significant differences were found between cephalothorax length, overall total length and egg length. Significant positive correlations within samples were also observed, between total female body length and both total egg number and egg string length in one of the samples examined.