Fish assemblages associated with shallow (4–7 m deep) artificial rocky habitats (i.e. breakwaters) have been assessed between July 2002 and September 2003, at the marine protected area of Miramare and adjacent areas outside the reserve (northern Adriatic sea). Our purpose was to: (1) detect possible differences between ‘protected vs fished’ breakwaters; and (2) compare two visual-census techniques for fish assessment (i.e. strip transects vs stationary points). The fish assemblages observed between protected and fished breakwaters during all four sampling periods were statistically different. More fish taxa were found at the protected than fished breakwaters, while there was no difference in total fish density. Most fish species targeted by fisheries had a greater density (e.g. Sciaena umbra, Dicentrarchus labrax, Sparus aurata, Diplodus vulgaris, Diplodus sargus and Diplodus puntazzo) and/or size (e.g. S. aurata and D. annularis) at the protected than fished breakwaters. There was a significant difference in fish assemblages due to assessment method. In general, the number of taxa was greater when assessed by strip transects than stationary points. Total fish density was almost unaffected by the method used, while total density of demersal fish (i.e. excluding schooling species) tended to be greater when evaluated by strip transects, although the difference was statistically significant only in one sampling period out of four. These results indicate that protection from fishing may have the potential to influence fish assemblages associated with breakwaters. Additionally, caution should be used when comparing fish assemblage data collected by different visual assessment techniques.

The development of the planktonic veliger larva of Mytilus edulis L. culminates in a swimming crawling stage during which the foot is of considerable importance in the selection of a settlement site. This stage has been described for many other bivalves (see Bayne, 1965) and has been given the term ‘pediveliger’ by Carriker (1961). The pediveliger of Mytilus edulis is negatively phototactic and positively geotactic during velar swimming (Bayne, 1964b) and is usually confined to water layers close to the substratum. The foot may be protruded during swimming and if it comes into contact with the substratum it adheres and a period of crawling commences. During crawling the larva progresses on the ventral or posterior surface of the foot by means of ciliary and muscular action. Crawling may result in attachment by secretion of the first byssus thread or alternatively the foot is withdrawn and velar swimming is continued until the next exploratory crawling phase. Mytilus larvae attach most readily to filamentous substrates in the field (Blok & Geelen, 1958; Bayne, 1964a).

Material of Cricosphaera carterae was examined cytologically with the acetocarmine technique. Nuclear division is similar to that found in higher plants. Investigations showed there to be a chromosomal alternation of generations, which corresponds to the morphological alternation. The motile phase is diploid, 2n = 42 ± 2, and the non-motile phase is haploid, n = 21 ± 1.

Stomach contents were analysed from three species of beaked whales which mass-stranded shortly after a naval exercise conducted in the Canary Islands in September 2002. Animals from such mass strandings often contain freshly ingested food in their stomachs and can provide a more reliable guide to feeding habits than other strandings. Food remains recovered from seven Cuvier's beaked whales (Ziphius cavirostris) consisted mainly of oceanic cephalopods, the most numerous being Taonius pavo, Histioteuthis sp., Mastigoteuthis schmidti and Octopoteuthis sicula. Many of the cephalopod species found in the diet appear to undertake daily vertical migrations, being found in shallower waters during the night and moving to deeper waters during the day. Single specimens of Blainville's beaked whale (Mesoplodon densirostris) and Gervais' beaked whale (Mesoplodon europaeus) had eaten both fish and cephalopod prey. The most numerous prey remains belonged to gadid fish and viperfish (Chauliodus sp.) respectively. These results are consistent with the limited published data on diet in these species, with Mesoplodon species having a relatively higher proportion of fish in the diet whereas Ziphius specialises on cephalopods.

Squids of the family Bathyteuthidae have generally been infrequently encountered in their deep-sea habitat. Remotely operated vehicles were used to observe seven individuals in situ in the Monterey Submarine Canyon, CA, USA. One of these was a female Bathyteuthis berryi holding a sheet with approximately 360 embedded embryos. Examination of this female after collection revealed the presence of a seminal receptacle on the buccal membrane. We present some potential costs and benefits of post-spawning egg care, a strategy that is now known for two families of deep-dwelling squids, but may turn out to be more common with the increasing exploration of the deep sea.

Siphonophores (Cnidaria: Hydrozoa) are dominant members of the carnivorous plankton, and they are known for their ability to produce bioluminescence. Here we describe two new calycophoran species (sub-family Prayinae) that are unique in their morphological and optical traits. One species, Gymnopraia lapislazula gen. nov., sp. nov., displays a dramatic form of blue structural coloration, and the other, Lilyopsis fluoracantha, sp. nov., bears an exceptional amount of fluorescence–enough to give a greenish cast during white-light illumination. We also introduce a consistent terminology for siphonophore axes and zooids, discuss characters important for distinguishing the known prayine genera, and suggest that the presence or absence of a disjunct pedicular canal could be of diagnostic value for the group.

All habitats are modified to some extent by the species that live within them. Kelp is known to have a very strong influence on the surrounding environment providing a habitat for a wide range of organisms including marine mammals, fish and invertebrates. Here we examine the consequences of a subtle shift in the relative abundance of two species of kelp, Laminaria digitata and Laminaria ochroleuca, and compare the holdfast epibiont assemblages on both. These species are morphologically very similar and both provide important biologically generated habitats. The distribution of these kelp species is predicted to alter as a consequence of climate change with L. ochroleuca extending its range northward and potentially outcompeting L. digitata in the north-eastern Atlantic. The epibiont fauna common to both species of kelp were predominantly made up of annelids, molluscs and bryozoans. Most of the epibiont flora we found on the holdfasts was from the class Rhodophyceae. Multivariate analysis showed that the richness of epibiont species associated with L. ochroleuca was significantly lower, a mean of 0.62 species per cm3, when compared to the northern species, L. digitata which had a mean of 1.13 species per cm3. Laminaria digitata also had more unique epibiont species indicating that species richness of holdfast assemblages is likely to decline if L. digitata is replaced by L. ochroleuca. These data illustrate the importance of studying biologically generated habitats when considering the potential consequences of climate change on marine assemblages.

Rimicaris hybisae sp. nov. is described from hydrothermal vent fields on the world's deepest seafloor spreading centre, the Mid-Cayman Spreading Centre (MCSC), Caribbean, at depths of 2300–4960 m. The new species is described and illustrated on the basis of 17 specimens. Brief notes on the distribution and habitat of the new species are provided. Molecular phylogenetic data from mitochondrial COI (460 base pair (bp)), 16S ribosomal RNA (549 bp) and nuclear 18S ribosomal RNA (576 bp) regions is used to complement the description. Morphological variation within R. hybisae sp. nov. and morphological affinities with previously described species are discussed. Based on morphological and molecular evidence, the new species is provisionally assigned to the genus Rimicaris, and differs from all known species in the genus by a distinctive pair of ‘pores' on the posterior lobes of its four-lobed dorsal organ. An emended diagnosis for Rimicaris is provided. Rimicaris hybisae sp. nov. is the first taxon to be described from MCSC vent fields. This record extends the known geographical range of Rimicaris into the Caribbean Sea and constitutes the deepest documented occurrence of alvinocaridid shrimp.

INTRODUCTION

Various authors during the last century (Johnston, 1847; Hincks, 1868, 1880) and more recently (D. Eggleston, unpublished†) have recorded a number of species as epizoites on the perennial bryozoan Flustra foliacea (L.) (Table 1); but the ecology of the ‘community’ (Hedgpeth, 1957) of epizoites and their interaction with the living substratum has never been studied. The sessile fauna of Flustra fronds includes species of seven different phyla, but it can be said of only a few that the fronds provide their typical habitat. For example, the barnacles are never very numerous and the lamellibranchs rarely reach adult size. This paper is concerned mainly with the most common epizoites: the hydroids and bryozoans. The distribution and orientation of some of these species on the fronds are of ecological interest.

A sensitive, specific and precise method for the determination of ammonia in sea water is presented. The method depends upon the oxidation of ammonia by chloramine-T and subsequent coupling with phenol to produce indophenol blue in an n-hexanol extract. Molar absorption coefficient ca 84,000. Values of ammonia measured in samples from the English Channel are given and the effect of freezing on samples for ammonia analysis is discussed.

Within the interstitial Cnidaria, the Hydrozoa dominate, with ten mesopsammic genera (living in the interstitial water of sandy bottoms), while the Anthozoa and Scyphozoa are represented by one genus each (Clausen & Salvini-Plawen, 1986; Bouillon & Grohmann, 1990). The only mesopsammic scyphozoans described so far are the small solitary polyps of the genus Stylocoronella, which is represented by two species, S. riedli (Salvini-Plawen, 1966) and S. variabilis (Salvini-Plawen, 1987). Little information is available on reproduction and nothing is known about the life-cycle of these interstitial scyphopolyps. By establishing a culture of the two Stylocoronella species, their development into undescribed stauromedusae could be observed for the first time

The eggs of two common cirripedes, Balanus balanoides and B. balanus, have been analysed at different stages of development for their lipid content.

Triglyceride and phospholipid are the main lipid components; small amounts of free fatty acids, lipochromes, sterols, and some very non-polar material (possibly hydrocarbon) are also present.

Lecithin followed by phosphatidyl ethanolamine make up a large proportion of the phospholipid fraction.

The fatty-acid spectrum is similar to that of other marine animals being rich in unsaturated fatty acids of which eicosapentaenoic (20:5) and docosahexaenoic (22:6) predominate.

Triglyceride is lost during development.

Initially some lecithin and phosphatidyl ethanolamine are lost during development, but they accumulate in the late stages.

Cardiolipin shows a marked increase in quantity during the late stages; this is presumably associated with increased cellular differentiation.

There is a tendency for all the components to approach the values for the adult bodies—taken when lipid reserves are minimal—as the embryos develop.

Proximate analyses of deep-frozen samples of Euphausia superba Dana obtained in December and January showed that protein was the major constituent, averaging just over 50% of the dry body weight. Lipid was much more variable; extreme limits of variation were from 6 to 33% dry weight, though the lipid content during January was distinctly higher than in December (means 27 and 13% dry weight respectively). This increase probably reflects a more intensive grazing by krill during the Antarctic summer. Increased lipid appears to be associated with some reduction in water content and in ash. Carbohydrate is low, the mean value for December being just under 5% dry body weight, but the content is slightly higher than that found for most zooplankton and may reflect the herbivorous habit of E. superba. The proximate biochemical composition of krill is similar to that of the boreal euphausiid, Meganyctiphanes norvegica.

There are two types of ground at Port Erin, differing widely in the general environmental conditions, and each with a characteristic type of urchin on it. The difference is sufficiently well marked for the local fishermen, who collect the urchins for sale to summer visitors, to distinguish them as different types. The littoral urchins from the Breakwater are larger and thicker shelled than those from the Breast. Their gonads reach a greater maximum size, and, in fact, never fall as low even as the maximum volume for the Breast urchin gonads. This difference is probably correlated with the much greater food supply on the Breakwater, since the gonad is the one organ of the body in which the animal can store reserve food material. Spawning commences in March or April and lasts for about two months, but is slightly earlier on the Breakwater than on the Breast. Ripening also takes place considerably earlier in both sexes on the littoral ground. Spawning seems to set in at a temperature of about 7° C., and the colder winter of 1931, compared with 1932, was associated with a later ripening and spawning, i n the former year. Similarly it is suggested that the slightly later spawning on the Breast than on the Breakwater is correlated with the slightly later rise in the temperature of the water on the deeper water ground in the spring.

Although the English Channel is the northern limit of the latitudinal range of Sphaerechinus granularis (Echinodermata: Echinoidea), this echinoid can produce locally high densities in Brittany, such as in the Glénan Archipelago (Bay of Concarneau) where a small-scale fishery has been exploited since 1985. The reproductive cycle, the growth patterns and the migration of the species in this area were studied from 1988 to 1992. Sphaerechinus granularis presents an annual reproductive cycle with a major spawning in the early spring. But inter annual variability in the time when spawning starts can be observed. A relationship is established between the date of onset of spawning and the climatic conditions during the whole period of gonadal growth. Recruitment is isolated in time and reflects the reproductive cycle.

The fouling of formerly clean sandy shores by the weathered residues of crude oil is all too familiar. Vigorous use of solvent emulsifiers can restore the beach ‘whiter than white’ but this damages the creatures which normally live in and on the sand. Unless the oil pollution is continual, the beach will usually rid itself of oil aided by waves and tides. Sometimes the disappearance of the oil may amount to no more than its bodily removal elsewhere or its burial out of sight, but inevitably, its ultimate destruction must be as the result of photochemical and biological processes. For intertidal sands where oil may become buried by wave action, the photochemical aspect is perhaps less important than for floating oil and the biological pathway is more important. In the experiments described here an attempt is made to investigate the rate of oil destruction by natural beach micro-organisms. Under the experimental conditions used, it is not difficult to sustain over a period of several months a fairly representative model of a beach with its populations of bacteria, diatoms and interstitial benthic animals.

A knowledge of the growth rates and feeding behaviour of planktonic copepods at natural food concentrations is important for an understanding of food-chain dynamics in the sea. In many areas of the open oceans average concentrations of particulate organic carbon rarely exceed 100 µ carbon 1-1, and even in coastal regions the maximum levels are probably only one or two orders of magnitude higher (Parsons, 1975). Thus, most herbivorous marine copepods live in a nutritionally dilute environment (Conover, 1968). In contrast to natural conditions, many laboratory investigations have been carried out at unnaturally high food concentrations, often more than one order of magnitude higher than those which might be expected in the sea.

The astropectinid asteroid Plutonaster bifrons (Wyville Thomson) occurs on the continental slope of the north-east Atlantic between 1000 and 2500 m depths. As in most deepsea animals, the factors limiting bathymetric distribution of this species are unknown. Eggs were fertilized in vitro and incubated through the early embryonic cleavage stages at pressures that correspond to depths from 0 to 3000 m. The highest percentage of normal development occurred near the peak of the species distribution (2000 m), and virtually no normal development occurred at a pressure corresponding to 3000 m depth. Develop-mental rate was retarded at pressures higher and lower than those found near 2000 m. These experiments indicate that embryonic pressure tolerances could determine both the upper and lower bathymetric limits of distribution for this species.

Macro and meiobenthic communities of two fishing areas (Vilamoura and Lagos) in the western part of south Portugal (Algarve coast) were analysed. Both locations had been under severe dredge-fishing impact until four years previously. Vilamoura has since continued to be dredged, while fishing activity in Lagos was stopped in 1995 as a response to overfishing. For each location, three replicate areas were analysed at depths of 7–9 m. In each of these areas, 18 quadrats for macrofauna and 12 cores for meiofauna were randomly sampled by SCUBA divers during September 1999. The Shannon–Weiner diversity index was higher for meiofauna in the fished area, whereas macrofauna diversity was higher in the recently non-fished area. Bray–Curtis dissimilarity between the two areas was 87·82%. Major differences were found between Ampeliscidea, Amphiura mediterranea, Spisula solida, Haustoriidae, Nemertinea and Diogenes pugilator populations at the two sites. There was higher abundance but lower biomass of potential macrofaunal scavengers in the fished area, and carnivore biomass was also higher in this area. Deposit-feeders dominated meiofauna abundance in both study areas. The community structure of the continuously fished area was dominated by small, opportunistic, short-lived species while the community structure of the recently non-fished area was dominated by more fragile and long-living sessile organisms.

The distribution and spatio–temporal variation of Helicolenus dactylopterus (Pisces: Scorpaenidae) population was studied from 816 bottom trawls developed along the Iberian coast. Multifactor analysis of variance was used to test the differences in abundance and biomass and cluster analysis was applied to detect differences in population structure. The results showed a bathymetric and latitudinal gradient in abundance and population structure along three geographic sectors in the surveyed area. In the southern area, the species was more frequent and showed a wider bathymetric distribution range than northwards. The depth range with the maximum frequency of occurrence was also wider in the southern area than northwards. Similar trends were observed in terms of abundance and biomass, with the highest and lowest indices in the southern and northern areas, respectively. The age composition of the catches showed that the population consisted mainly of young-of-the-year and juvenile fish. This fraction of the population is well represented, at a mesoscale, along the whole surveyed area, but adults are well represented only at a local scale, at the deepest strata surveyed in the southern area. In this case, recruits of age 0 and juveniles up to 4-y old were restricted to depths shallower than 500 m, while adult fish older than 6 y of age appeared below this depth. In the southern area, seasonal changes in the population structure were also observed, with modes of small fish (3–6 cm) from March to June, as a consequence of the species recruitment to the bottom. Some direct and indirect factors of biogeographic, environmental and anthropogenic origin affecting the observed gradient are discussed.