The examination of five females of the deep-benthic octopus Graneledone pacifica—a large-egged species: mature ovarian egg length >20 mm—showed that their developing oocyte size-distribution was normal in two specimens at an early maturation stage (largest oocyte length=3 mm), bimodal in two specimens at a more advanced stage (largest oocyte length=6 and 8 mm, respectively), three-modal in the farthest advanced stage specimen (largest oocyte length=14 mm). According to the literature, the simultaneous occurrence of oocyte cohorts at different oogenic stages, including a distinct cohort of oocytes at an advanced maturing stage in one specimen, suggests that G. pacifica is a multiple spawner.

This study explored whether the growth and sexual maturity of female John Dory (Zeus faber) differed in relation to hydrographic conditions at sample sites in the East China Sea. John Dory were collected around the margin of the continental shelf from the north-east to south-west waters of the East China Sea, and seasonal changes in spatial distribution were unclear. These probably reflected physiological constraints on salinity, as John Dory are distributed only in waters of high salinity. Thermal gradients along latitudinal lines were evident within sample sites. The northern population was subject to lower temperatures than the southern population during all sampling periods. There were no significant differences in length–age relationships between sampling locations, although the northern population had better body condition than their southern counterparts for a given length. However, northern John Dory matured earlier than their southern counterparts with the same relative condition factor.

In this study, an overview of the current species composition of ophiuroids off Helgoland, German Bight (North Sea) is given. In addition, abundance and distribution of ophiuroids on different types of soft bottom sediments taken by van Veen grab samples around Helgoland were recorded. The literature was reviewed in order to outline the diversity of ophiuroid species over the past 130 years in the inner German Bight. In the historical literature, quantitative references often apply to verbal descriptions and thus make comparisons to modern data and assessment of possible changes in abundance rather subjective.

In total, six ophiuroid species were identified off Helgoland: Acrocnida brachiata, Amphiura filiformis, Amphipholis squamata, Ophiothrix fragilis, Ophiura albida and Ophiura ophiura. The species found in this study had also been reported by previous investigators and are regarded as ‘common’ species in the German Bight. Occasional findings in this area refer to Amphiura chiajei, Ophiopholis aculeata, Ophiocten affinis and Ophiura sarsi, which are regarded here as ‘rare’ species. These findings, however, do not indicate sustainable changes in the species diversity over time.

Apart from Acrocnida brachiata, a newcomer in the 1970s, findings of the common species mentioned above can be dated back to 1875. Therefore, a fairly stable composition of brittle stars is represented in the inner German Bight during the past 130 years.

Salinities in some normally-closed estuaries in the central south coast of Western Australia are now frequently becoming highly elevated. This is due to: (1) high evaporation rates in water volumes that, by summer, are already low as a result of atypically dry winters; and (2) increased salt run-off following vegetation clearing in the catchments. A few black bream (Acanthopagrus butcheri) died in the basin and lower reaches of the main tributary of Culham inlet when salinities reached ∼ 77 and 67, respectively, and an estimated 1.3 million black bream died in the tributary during the next two months when salinities continued to increase. All black bream in the basin and the lower reaches of the tributary of another estuary were apparently killed when salinities reached ∼ 83–85. It is proposed that A. butcheri becomes stressed at salinities of 60 and typically die before they reach ∼ 85. In both estuaries, a rock bar in the tributary prevented black bream from moving to refugia in upstream areas where salinities were lower.

Skeletal development of Ophiactis resiliens and Amphiura constricta was examined to determine characters that could be used to identify the juveniles of these species, which co-occur in algal turf habitat. Juvenile O. resiliens recruit to turf after a planktonic larval stage while A. constricta recruit through release from brooding adults. Skeletal development in O. resiliens and A. constricta is typical of most ophiuroids with diagnostic adult characters taking some time to appear. The main characters that can be used to distinguish the two species from an early stage are the number and arrangement of the oral papillae and the presence of disc spines. In O. resiliens diagnostic adult skeletal characters developed at 1.5 mm disc diameter. In A. constricta most identifying adult characters were evident at 700 μm disc diameter. Identification of juvenile O. resiliens is assisted by the presence of disc spines and thorny arm spines, features that disappear as the juveniles grow. Juvenile A. constricta did not develop disc spines or thorns on the arm spines.

Environmental cues such as photoperiod and water temperature are often used by fish as a sign to begin reproduction. However, even after the reproductive cycle has started there are other signs, such as the moon phase that may affect the number of eggs laid by some fish species. The existence of a moon effect has never been investigated in any fish of the sparid family.

In the present study, the effect of moon phase was observed on eggs laid by two Sparus aurata in indoor tanks over a four month period, from January to May, 2003. During this period a peak in eggs laid was observed around the Full Moon. A total of 8644 g and 5653 g of eggs were collected, 4535 g corresponding to the Full Moon and 2882 g to the New Moon.

The presence of fin whales in the Mediterranean Sea has been documented since ancient times. In spite of this, reliable information on their ecology and distribution is limited to the north-western part of the basin. Recent genetic studies have demonstrated that Mediterranean fin whales comprise a separate population with very limited gene flow with their North Atlantic co-specifics. Although both published and anecdotal information reports their presence in the south central Mediterranean during winter, there is no information on habitat use. In February 2004, a 14-day boat survey was carried out in the waters surrounding the island of Lampedusa, where fin whales occur at this time of the year. A total of 20 fin whale groups (average group size two animals) were encountered. In each encounter the animals were engaged in surface feeding activity. From plankton samples and underwater video, the prey species was identified as the Euphausiid, Nyctiphanes couchi. The information obtained suggests that this area may be an important winter feeding ground for fin whales. The results represent significant new information on fin whale ecology in the Mediterranean, with associated conservation and management implications.

The hindgut caecum of the deposit-feeding echinoid Echinocardium cordatum harbours a symbiotic bacterial microflora, organized into layered mats around detrital particles owing to the proliferation of filamentous bacteria. The bacterial community was analysed using 16S rRNA gene analysis and fluorescence in situ hybridization. The purpose was to characterize its biodiversity and to identify its predominant members. The majority of the 16S sequences belong to the δ-Proteobacteria (61.5%), the Bacteroidetes and the Firmicutes constitute the two other main bacterial groups (respectively 23.1% and 15.4%). A total of 41% of the δ-Proteobacteria clones isolated belong to a bacterium of the genus Desulfonema for which a specific oligonucleotide probe was designed, enabling identification of its distribution in the nodules.

The gonadal development and morphometry of Appendicularia sicula (Appendicularia: Fritillariidae) were studied by means of histological sections and from the measurement of several characters. Based on morphometric measurements, the ingestion and clearance rates and the percentages of consumed chlorophyll-a were also estimated. The gonadal development is similar to that of Fritillaria pellucida. A small dorsal ovotestis, which originates ovary and testicle, shows large somatic nuclei inside. In the ovary these somatic nuclei are surrounded by a single layer of germ cells nuclei, whereas in the testicle they are found between the small nuclei of the germ cells. As the development proceeds, the large somatic nuclei are resorbed in both gonads, and the testicle finally envelopes the ovary posteriorly. After spermatozoids emission, the rectum is shown occupying most of the body volume. The length of the rectum shows a positive allometric growth in respect to the length of the trunk, which can be ascribed to its continuous accumulation of matter due to the lack of an anus. The relationship obtained between trunk length (TL, μm) and dry weight (DW, μg) was DW=2.24×10−11 TL4.098. Applying this equation, a two-fold increase in length would correspond to a 42-fold weight increase. For specimens with an advanced sexual maturity (400–450 μm TL), we estimated a mean autotrophic ingestion rate of 0.17 μg C ind−1 d−1 and a mean clearance rate of 5.01 ml ind−1 d−1. The percentage of total chlorophyll-a consumed by the A. sicula population was 5.13%. This value is similar to those reported for other appendicularian species in different temperate seas.

The food and feeding ecology of the striped dolphin, Stenella coeruleoalba, in the oceanic waters of the north-east Atlantic were studied using the stomach contents of 60 striped dolphins caught in the albacore drift-net fishery throughout the summer months of 1992 and 1993 off the Bay of Biscay. Thirty-eight per cent of these dolphins were calves (0–1 years old), 25% were juveniles (2–8) and 37% were mature adults (9–32, of which 7 females and 14 males). The diet was found to be primarily composed of fish (39% by mass (M)) and cephalopods (56% M) and secondarily of crustaceans (5% M). The most significant fish family identified was the lanternfish (24% M) with Notoscopelus kroeyeri and Lobianchia gemellarii being predominant. Among squid, the oceanic Teuthowenia megalops and Histioteuthis spp. were the most significant. The pelagic shrimp Sergastes arcticus and Pasiphaea multidentata were the most prevalent crustaceans. Prey sizes ranging from 30 to 170 mm accounted for 80% of the prey items while 80% of the reconstituted biomass consisted of prey measuring between 60 and 270 mm. Prey composition and size-range differed slightly with sex and age or body size of the dolphins. The state of digestion of food remains suggested that predation took place at dusk or during the early hours of the night on which the dolphins were caught.

We report on the first successfully deployed time-depth recorder on an immature Kemp's ridley turtle in a coastal foraging habitat in south-west Florida. The turtle exhibited three distinct dive patterns interpreted as: post release stress (26 h) post release transition (8 h) and normal (>34 h). The normal pattern consists of short periods on the surface followed by longer periods on the bottom in 2–3 m of water which we speculate is foraging behaviour. Overall, the turtle spent 94% of the time submerged during the normal period. The turtle spent significantly more time submerged at night than during the day, suggesting the turtle was resting. Night dives were consistently longer than dawn, day or dusk dives.

Temporal variation in a temperate cryptobenthic fish assemblage at the Arrábida Marine Park (Portugal) was assessed by visual surveys during 2002 and 2003. A total of 9596 fish from 11 families and 30 species was recorded. There were no changes in structure or density at the assemblage level between years, whereas diversity changed significantly due to a higher number of abundant species in the second year. A similar seasonal trend was found between years, with a significant overall density increase in autumn. This is partially explained by the arrival of new recruits of some of the most abundant species in the assemblage. Assemblage diversity and structure also changed across seasons. A group of species encompassing Gobius xanthocephalus, Tripterygion delaisi, Parablennius pilicornis, Gobius paganellus, Lepadogaster candollii and Lepadogaster spp. were analysed in detail. The temporal patterns of two of the most abundant species, G. xanthocephalus and T. delaisi, mimicked the overall temporal patterns of the assemblage. We suggest that the inter-annual stability in density of this subtidal fish assemblage may be similar to what has been reported for the intertidal and that strong post-settlement processes are probably shaping this assemblage.

The cyclone Erica (Class 5) hit the South Lagoon Marine Park of New Caledonia on 14 March 2003, in the midst of a survey conducted on coral reef fish and habitat of Larégnère and Crouy reefs. Such perturbation was exceptional for the area. Nine stations had already been sampled (8–11 March 2003) when the cyclone hit the reefs. These stations were sampled again just after the cyclone (23 March–15 April 2003) and 20 months later (14–16 November 2004). Erica had a significant initial impact on habitat characteristics. The fragile coral forms cover (branching, tubular and foliose) decreased significantly, resulting in a loss of habitat for the fish communities. Species richness and biomass of the commercial reef fish and the Chaetodontidae decreased just after Erica, but not the density. The species assemblage was modified on the stations with the lowest remaining live coral cover. The loss of shelter modified the behaviour of potential prey, which constituted unusual shoals and attracted predators. Twenty months after Erica, the habitat had not recovered and the broken coral colonies were transformed into rubble or colonized by algae. The nature of the mid-term impact on the fish communities was different and more significant than the initial impact. Species richness per station, density and biomass were significantly lower than before and just after Erica. This pattern was confirmed for all the main families, with the exception of Acanthuridae. A different fish assemblage was observed on all stations 20 months after Erica. Herbivorous species and benthic macro-invertebrate feeders associated with rubble replaced the coral associated species that characterized the assemblages before the cyclone. When a Class 5 cyclone affects an area where perturbations of such intensity are uncommon, its impact is immediate and the mid-term consequences are even more significant. A complete modification of the structure of the habitat and the fish assemblages is observed. The consecutive recovery should be a long process.

Here we provide baseline data on the distribution and abundance of Mola mola within the Irish and Celtic Seas, made during aerial surveys from June to October during 2003–2005. These data were considered in conjunction with concurrent observations of three potential jellyfish prey species found throughout the region: Rhizostoma octopus, Chrysaora hysoscella and Cyanea capillata. A total area of 7850 km2 was surveyed over the three years with an observed abundance of 68 sunfish giving a density of 0.98 ind/100 km2. Although modest, these findings highlight that the species is more common than once thought around Britain and Ireland and an order of magnitude greater than the other apex jellyfish predator found in the region, the leatherback turtle (Dermochelys coriacea). Furthermore, the distribution of sunfish sightings was inconsistent with the extensive aggregations of Rhizostoma octopus found throughout the study area. The modelled distributions of predator–prey co-occurrence (using data for all three jellyfish species) was less than the observed co-occurrence with the implication that neither jellyfish nor sunfish were randomly distributed but co-occurred more in the same areas than expected by chance. Finally, observed sunfish were typically small (∼1 m or less) and seen to either bask or actively swim at the surface.

Spawning temperature preferences for sardine (Sardina pilchardus) in the eastern North Atlantic were determined from egg survey data. These were compared with climatological temperature cycles (1986–2002) derived from satellite observations, by geographical region, to predict spawning seasons. Optimum spawning temperatures were determined as 14.0–15.0°C from the English Channel to Portugal and 16.0–18.0°C for all north-west African regions. Spawning seasons were closely related to the general latitudinal trend of the annual temperature cycle, with modification by upwelling in the western Iberian and north-west African regions. Some differences between temperature-based spawning season predictions and field observations were related to variations in seasonal plankton production. Correlations in the annual time-series of favourable spawning temperatures suggested relatively strong linkages between the southern areas from Portugal to Senegal. There was no consistent relationship between annual variations in extent of temperature-predicted spawning seasons and observed field abundance of eggs.

Through a series of ichthyoplankton surveys carried out off central Chile, we characterize the offshore spawning and coastal nursery ground of the bigeye flounder Hippoglossina macrops. Eggs were collected in higher abundances over the continental shelf during late winter, over the shelf-break in mid spring, and at the continental slope in late summer, showing a seasonal depth gradient in spawning. No significant spawning was detected nearshore (less than 8 km offshore). Field data suggest a longitudinal progression from offshore to onshore of larval stages from preflexion to transformation stage. Finally, vertically stratified samples showed that eggs and larvae were present mainly in the upper 100 m. We discuss the potential onshore transport of early life stages of H. macrops through the compensatory flow of Equatorial Subsurface Waters that balances the surface offshore transport in the Ekman layer during upwelling events. Additionally, larval development from yolk-sac to transformation stage is briefly described.

Here we report on a previously undocumented facultative symbiosis involving the wrasses Labroides dimidiatus and Thallasoma amblycephalum living in association with two species of sea anemones, on coral reefs in the north-western Pacific. By SCUBA diving we observed juvenile L. dimidiatus occurring in Entacmaea quadricolor (solitary type) cleaning the anemonefish Amphiprion frenatus and in Heteractis magnifica cleaning the anemonefish Dascyllus trimaculatus. Thallasoma amblycephalum co-existed in H. magnifica with the anemonefish D. trimaculatus, A. ocellaris and L. dimidiatus.