The structure and distribution of the sponge community in five sites and four habitats in Cagarras Archipelago, Rio de Janeiro, Brazil, are described. The archipelago has three major islands (Cagarra, Palmas, and Comprida), and four islets. Qualitative samples were taken by SCUBA diving in the three islands and in two islets, and quantitative samples were taken in Palmas Island only. Cluster analysis using Jaccard's coefficient on qualitative data grouped the two islets (Cagarra Bank and Cagarra Islet), which are more exposed to wave action, and the three islands formed a group of relatively sheltered sites. Cluster analysis using Bray–Curtis coefficient on quantitative data from different habitats in Palmas Island allowed distinction of three groups of samples: overhangs, shallow horizontal surfaces (6 m depth), and vertical walls plus deeper horizontal surfaces (17 m depth). Sponge abundance was greater in overhangs (61·2 ind m−2), which were dominated by Protosuberites sp. and Clathrina conifera. Abundance was reduced in vertical walls (31·1 ind m−2) and deep horizontal surfaces (16·8 ind m−2). Pachychalina sp. dominated the deep horizontal surfaces and Clathrina conifera was dominant in overhangs. Values of Shannon's diversity in overhangs, vertical walls (both with H′=2·1 bits ind−1) and deep horizontal surfaces (H′=1·7 bits ind−1) were moderate and similar, whereas in shallow horizontal surfaces the sponges were both less diverse (H′=0·37) and less abundant (8·5 ind m−2). Shallow horizontal surfaces were dominated by Hymeniacidon heliophila. The reduced species richness of the sponge community in Cagarras Archipelago when compared with other sites in Brazil and elsewhere is probably due in part to the pollution from the city of Rio de Janeiro. Wave action appears to reduce the number of sponge species at a local scale, whereas substrate inclination affects more strongly the species composition and abundance than the diversity of sponges.

Structural adaptations of the mouthparts and digestive tract of four talitrid amphipods were examined in relation to diet, habitat and phylogeny. The species differed in their habitat relative to the shoreline and also in their diet: a 5-dentate ‘sandrunner’, Talorchestia species II (a mid to low shore intertidal diatom feeder), a 5-dentate sandhopper, Talorchestia marmorata (a strandline kelp feeder); a 4-dentate sandhopper, Talorchestia species I (extreme high shore, feeding on spinifex grasses), and a 4-dentate landhopper, Keratroides vulgaris (forest leaf litter, litter feeding). Gross structural characteristics of the mouthparts were similar among all three Talorchestia species reflecting their phylogenetic relatedness. Increased setation and minor structural differences among the Talorchestia species could be attributed to dietary differences, reflecting the zones across the shoreline that they inhabit. Mouthparts of K. vulgaris were elongate, with markedly different setation to the Talorchestia species, reflecting its more distant phylogenetic position and its diet of decaying leaf litter. Digestive tract structure was more conserved among all species due to their phylogenetic relatedness. The gross digestive structure conformed to the general plan exhibited by most gammaridean amphipods. However, an additional pair of lateral pyloric caeca was evident in all species, the function of which is uncertain.

Information on Balaenoptera edeni strandings along the Brazilian south-east coast and feeding associations with other marine vertebrates are reported. A total of 19 strandings were observed from 1972 to 2003 along ≈1200 km of coast. Strandings were evenly distributed among seasons with no distinguishable peaks. Besides the stranding data, opportunistic observations on Bryde's whales engaged in feeding activities were reported from nine cruises along São Paulo and Rio de Janeiro State coasts (22–24°S). Bryde's whales were observed preying on Brazilian sardines (Sardinella brasiliensis) in at least three events, and possibly two others. Associations with other marine vertebrates were observed, and included dolphin fish (Coryphaena hippurus), little tunny (Euthynnus alletteratus), unidentified sharks, terns (Sterna hirundinacea, Sterna spp.), brown boobies (Sula leucogaster), frigate birds (Fregata magnificens), parasitic jaeger (Stercorarius cf. parasiticus), albatrosses (Thalassarche spp.), and bottlenose dolphins (Tursiops truncatus). Stranding data and on-board observations support the hypothesis that Bryde's whales are common in coastal waters of south-eastern Brazil.

Adult female loggerhead sea turtles (Caretta caretta) nesting in Japan use different feeding habitats as a function of body size. The Argos location data of two females inhabiting either oceanic or neritic habitats were analysed to infer their foraging and diving behaviour. There were no significant differences in the number of transmissions received per satellite pass, the number of locations per day, and the frequency of location-accuracy classes between oceanic and neritic females, implying that there was little difference in the time these two turtles stayed at the sea surface. Two possible forage-diving behaviours are suggested for these turtles: (1) both dive duration and depth were not different between the two feeding habitats; or (2) although dive duration was not different between feeding habitats, dive depth was different.

A new genus and species of sabellid polychaete from an organically enriched beach in São Sebastião, State of São Paulo, is described. Kirkia heterobranchiata is unique among sabellids for brooding the embryos on the dorsalmost pair of radioles, which exhibits several modifications for this purpose, rather than on ventral radioles. Morphologically, K. heterobranchiata is most closely related to Perkinsiana riwo, here referred to as the new genus, as suggested by phylogenetic analysis. The new genus is characterized by the shape of the lips (dorsal lips roughly triangular, broader than long; ventral lips lower, ventrally fused and distally rounded), by the absence of both radiolar and pinnular appendages, by having uncini with very short handles in both the thorax and abdomen, and by the ability to brood embryos in cocoons attached to the branchial crown.

To characterize the ultraviolet (UV) light-absorbing function of the ascidian tunic, the light absorption spectrum was compared in 22 ascidian species collected from tropical and temperate waters. Non-photosymbiotic ascidians (17 species) had transparent tunics transmitting both visible and UV light, or pigmented or opaque tunics equally absorb both UV and visible light. However, a prominent absorption peak around 320 nm was exclusively found in the colonial ascidians hosting the algal symbiont Prochloron sp., and this absorption peak corresponded to absorption of UV-A (320–400 nm) and UV-B (280–320 nm). The UV-absorbing substances were extracted with methanol. They were mycosporine-like amino acids (MAAs): mycosporine-glycine, palythine, shinorine, and porphyra-334. The MAAs are thought to be synthesized by the shikimic acid pathway that does not occur in animals. Since the isolated Prochloron cells contain MAAs, the symbionts are the most possible candidates as the source of the MAAs in the tunic. In Diplosoma virens, the composition of MAAs was different between isolated Prochloron cells and colony residue from which Prochloron cells were extracted.

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

Data on age and reproduction of the rabbitfish at the Portuguese continental slope are presented. Ages were estimated based on transverse sections of the dorsal spine. Differences in growth patterns were detected between sexes—males grow slower and are smaller than females. The results from histological analysis of different development stages of testes indicated that the macroscopic scale used is well adapted to rabbitfish sampled in Portuguese waters. In females and excluding macroscopic Stage 4, which according to the adopted scale corresponds to an active phase, all the remaining stages were identified in the samples. Ovarian fecundity was estimated as 6·46±2·32 oocytes (females range: 45·0 to 70·0 cm pre-supra caudal fin length [PSCFL]). Length of first maturity in males (40·7 cm PSCFL) is lower than in females (45·9 cm PSCFL).

The diet and functional biology of the digestive system of the cephalaspidean gastropod Haminoea orbygniana was investigated by gut content analysis of animals collected in the Ria Formosa, a coastal lagoon in southern Portugal. The results show that this species is herbivorous, stenophagic and probably non-selective, feeding mainly on diatoms (67·61%) and occasionally on vegetal detritus (4·16%) and Foraminifera (0·04%), but also including sand grains as an important part of the gut contents (28·34%). The role of the gizzard plates in the fragmentation of diatom frustules was demonstrated and is discussed. Data reveal that this process, although possibly important for the digestion and assimilation of food, seems not to be crucial. The role of sand as an additional food source and as an accessory tool complementary to the gizzard plates is discussed. A general review of the diet within the family Haminoeidae is presented, with all recent work indicating that they feed on diatoms and green algae.

A preliminary ontogenetic series of common pandora (Pagellus erythrinus) larvae is presented showing that larvae of this species possess an occipital crest from 4 to 16 mm total length. Such a trait has been described as a diagnostic character of the larvae of another sparid fish, namely Pagrus pagrus, and has been erroneously considered as being absent in all other Sparidae species. This caused confusion and erratic identifications of the two species of larvae in Mediterranean ichthyoplankton investigations.

The John Dory, Zeus faber, has a pair of intrinsic sonic muscles on the swimbladder wall and produces sounds by rapid contractions of the muscles. The physical properties of the sounds and the detailed innervation pattern to the sonic muscle were investigated. The dory emitted two types of the sounds: ‘bark’ and ‘growl’. The bark consisted of continuous multiple pulses and lasted about 85 ms on the average. The growl consisted of a group of intermittent single-pulses and lasted for 50 ms to 1·2 s. The main frequencies of both sounds were almost similar and ranged between 200 to 600 Hz. The sonic muscles were innervated by the sonic branches of the first to fourth spinal nerves. The innervation from the first spinal nerve was newly revealed in the present study. A total of 1700 myelinated axons innervated the sonic muscles on both sides. There were no sex differences in the sonic muscle size as judged by the sonic muscle–somatic index (male: 0·675%, female: 0·670%).

Concentrations of elements in the sagittal otoliths of juvenile white anglerfish (Lophius piscatorius) from five locations in the north-east Atlantic were measured to test for evidence of segregation in the early life stages. The concentrations of some elements, notably copper, were different between locations. As such, the results suggest limited exchange between locations during some period of the early life history. The relevance of these results to our understanding of population structuring is discussed in relation to recent information on anglerfish movements and genetic structuring.

Male Chondracanthus lophii was studied using light and electron microscopy. Observations on external morphology and internal anatomy are presented. Males possess a full set of functional mouth parts, the digestive system is active and the dominant cell type in the midgut is identified as the vacuolar type B-cell, but the gut is a blind ending sac with no anus. The gut contents were a homogenous, amorphous mass. The combination of active feeding and digestion with a blind ending gut supports the inference that males feed on special secretions produced by glands in the nuptial organs of the female. It is speculated that dependence on such secretion reduces or eliminates the production of faecal matter. Observations on the reproductive system confirmed the typical chondracanthid pattern.

In Mar del Plata the octocoral Tripalea clavaria is highly abundant on the different quartzitic rocky outcrops 18–20 m deep. Reproductive aspects of T. clavaria including its distribution and population structure have been described. Monthly sampling and observations were carried out by SCUBA diving from November 2000 to October 2001 at Banco del Medio (38°10′S 57°28′W). Tripalea clavaria occurs in patches; most colonies were 3·0–8·9 cm in height. The species appears to be a gonochoric brooder. Female colonies were significantly more abundant than males, which could be identified only from February to June, when spermaries were present. Oocytes were found even in very small colonies (from 3·5 cm height), being 40 to 200 μm in diameter, the predominant size-group around the year. Development of the oocytes required several months, beginning in May and ending with the production of larvae from March to May. Young, stalked oocytes were found at the base of the polyps attached to the mesenteries in May–June. During the following six months they grew in size; maximal oocyte diameter was 700 μm, observed in April/May. Asexual reproduction was negligible, indicating that population maintenance is based on sexual reproduction.

Fish assemblages associated with wave exposed and sheltered sides of breakwaters, and with adjacent sandy habitats were studied in western Calabria (Mediterranean Sea, south-western Italy). Overall, 26 fish taxa were recorded (21 associated with exposed breakwater sides, 21 with sheltered sides, and four with sand). Fish assemblages significantly differed between breakwaters (both sides) and sand, and, to a lesser extent, between exposed and sheltered sides of breakwaters in terms of whole assemblage structure, densities of species, and juvenile stages.

Spatial surveys of marine benthic habitats and biota based on the interpretation of acoustic data were carried out at two sites in the eastern English Channel each representing different scales of geographic area and intensity of survey. A small area (4×12 km) crossing the Hastings Shingle Bank was surveyed at a relatively high intensity (track spacing 400 m) and was nested within a larger area between Hastings and Dungeness (12×40 km), which was surveyed at a lower intensity (track spacing 2 km). Surveys were conducted with two acoustic ground discrimination systems (AGDS), RoxAnn and QTC-VIEW and the primary purpose of the investigation was to compare the performance of the two AGDS using a common approach to analysis of the different data outputs (E1 and E2 for RoxAnn and the Q eigenvectors from QTC-VIEW). Exploratory data analysis using variography indicated that interpolation between tracks was justified for the smaller site to create a complete coverage, but was limited to the creation of a digital image of the track data for the larger area. Grab and video sample data were available for supervised classification of the AGDS data and interpreted sidescan images for comparison with unsupervised classification. Both AGDS gave similar outputs, although RoxAnn consistently gave slightly better levels of performance than QTC-VIEW as measured using error matrices. Although the investigation was not designed to compare the performance of AGDS and sidescan, the outputs from AGDS were similar to the visual interpretation of the sidescan sonar data. It was concluded that despite the inherent limitations of AGDS, they may be suitable for providing distribution maps at a broad scale that can give a context for the interpretation of finer scale survey of smaller, nested areas.

The population dynamics in the coastal bacterioplankton community off Plymouth (UK) was studied in samples proportionally diluted (99%, 90%, 66% and 0%) with sterile seawater, incubated in the dark for 2–4 days and monitored by flow cytometry. Nucleic acid content of cells, stained with SYBR Green I DNA specific dye, was used as an index of a genome size. Using flow sorting and fluorescence in situ hybridization (FISH) with a set of ribosomal RNA targeted oligonucleotide probes, the phylogenetic composition of dominant cytometric groups of bacterioplankton was determined to be similar during growth in the dilution series. The proportion of the low nucleic acid (LNA) group decreased and correspondingly the high nucleic acid (HNA) groups increased with dilution. The assimilation rates of free amino acids, a highly labile nutrient pool, were determined by flow sorting the dominant groups after short incubations with 35S-methionine tracer. The relative cellular amino acid assimilation by the LNA cells increased with dilution, while the activity of the HNA cells either decreased or remained unchanged. However, highly metabolically active LNA bacteria were overgrown by the HNA bacteria, presumably because the small genome size—an adaptation to living in an oligotrophic environment—did not allow the LNA group to grow sufficiently fast to compete with the HNA group under experimentally reduced grazing pressure. To examine the experimental results a numerical model of bacterioplankton population dynamics was formulated based on the hypothesis that the LNA cells consume only a labile fraction of organic nutrients (amino acids etc.), while the HNA cells feed on both the labile and more refractory sources of nutrients, and that in the absence of phytoplankton the labile source of nutrients is produced entirely by the bacterivorous flagellates. The model simulations gave credence to the hypothesized primary dependence of the LNA group on labile organic nutrients recycled within the microbial loop.

The structural parameters of sponge-dominated benthic communities from two Mediterranean caves in two seasons, autumn (November) and spring (June) were compared. The percentage of species in common between communities in each cave was calculated as a rough estimate of the capacity of species dispersion in each cave. The Shannon diversity index and Kulczynski similarity index were calculated for each community. Moreover, we studied the spatial distribution, patchiness and interspecies contacts of the most abundant species. The value of α-diversity was quite constant among communities of the Cabrera cave but decreased from the external to the innermost community in the Medes cave. The Kulczynski similarity index was generally lower among samples of the Cabrera cave. The most abundant sponge species showed a predominantly clumped distribution, especially in the most internal communities of the two caves. The innermost community of the Medes cave had the highest number of patches. Finally, the study of contacts among species that were non-random (meaning species that were in contact with a given species significantly more or less frequently than expected) showed that they were very common in the two seasons and in all communities, indicating the importance of biotic associations among benthic species in cave assemblages.

Slope Water anticyclonic Oceanic eDDIES (SWODDIES) are typical mesoscale features of open-ocean waters of the southern Bay of Biscay which usually develop in winter by shedding from the seasonal poleward current flowing along the northern Spanish slope. These eddies have been intensively studied from the physical perspective. However, their effect on the distribution of biological properties and on the functioning of the pelagic ecosystem has not been assessed so far. To this aim, a sea-truth, multidisciplinary and comprehensive study of a SWODDY was carried out in summer 1998. The eddy, radius of ≈50 km, was initially centred at 45·5°N 6·0°W, being characterized by a relatively homogeneous core of water in the centre of the eddy extending from 80 to about 200 dbar. In the central region of the core, temperature (12·55–12·75°C) and salinity (≈35·70) values were higher than outside the eddy. The optical properties of the eddy also differed from those of the surrounding waters. A distinct biological signature was found associated with the eddy. Depth-integrated chlorophyll-a concentrations were 25% higher at the eddy centre where upward doming of the seasonal pycnocline (up to 30 dbar) occurred. Enhanced phytoplankton biomass was related to a higher contribution of >10 μm cells, mainly represented by diatoms and chrysophyceans. Phytoplankton and mesozooplankton species composition in and outside the eddy differed significantly reflecting the coastal origin of the water parcel trapped by the eddy. The sharp modification of the planktonic community composition, biomass and associated size-structure caused by slope water oceanic eddies are likely to exert a significant effect upon the upper trophic levels of the pelagic ecosystem of the southern Bay of Biscay.

An assemblage of shallow-water fish was sampled with a small beach seine over monthly 24-h periods between April 2000 and March 2001 at the sandy beach Duće Glava in the eastern Adriatic. Monthly sets of samples were divided into day and night catches to examine the stability of diel differences in assemblage structure over a 1-y period. A total of 61 species was caught, of which six were exclusively diurnal and 12 were nocturnal. According to abundance and biomass of individuals during day and night, the most abundant species were categorized into several groups. Ophidion rochei was exclusively nocturnal, while Nerophis ophidion and Echiichthys vipera were mostly nocturnal. Diplodus annularis and Mullus surmuletus were slightly nocturnal. Diplodus vulgaris, Pomatoschistus marmoratus and Atherina boyeri lacked a diel pattern. Sardina pilchardus, Lithognathus mormyrus, Atherina hepsetus, Sarpa salpa and Mullus surmuletus abundance peaked for a few months, probably related to timing of spawning and recruitment. At the assemblage level, the diel per cent similarity index indicates that there were major differences between the day and night assemblages in April, September, March, and August with respect to number of individuals and September, October, May and March with respect to biomass.