The pygmy killer whale Feresa attenuata is a poorly understood species that occurs in tropical and warm sub-tropical waters worldwide. The true range of these animals is not well established and there have been reports of them in temperate waters of the South Atlantic and Pacific Oceans. At 1746 h on 24 April 1997 at 45°15′76″N 30°56′54″W the first of two groups of small robust cetaceans were observed by experienced cetacean observers during a survey carried out aboard the P&O Portsmouth cruise ferry ‘Pride of Bilbao’. At 1820 at position 45°25′96″N 40°00′94″W on the same day a second group of animals of this species was encountered. In both cases the cetaceans were in close proximity to cetaceans with new born or first year calves. Identification information was recorded by the observers and the animals were identified as pygmy killer whales. These records represent the first in the Bay of Biscay and the most northerly records for this species.

A series of measurements were taken from 50 random examples of the arborescent sponges Raspailia ramosa and Stelligera stuposa at a number of sites and depths at Lough Hyne, Co. Cork, Ireland. Sites ranged from fast flowing habitats, experiencing little sediment settlement, to the converse where current flow was extremely slight and sediment settlement rates high. Depth intervals at which sponges were measured ranged from 6 to 24 m. Sponges of both species varied with respect to measurements taken and the growth proportions (ratios of measurements taken). The greatest morphological differences occurred between depth and current extremes. However, at the most sedimented site (24 m) branching complexity of both species actually decreased in opposition to the proposed current models. It is discussed that simple morphologies (such as singly dichotomized sponges) may be better suited to extremely sedimented regimes being more erect than larger, more complex specimens. Other biological factors that may limit branching complexity are considered and emphasis is placed upon the possible inadequacies of community or group level models of morphological adaptation.

Changes in weight, histology and visual appearance of ovaries from a field population of Pecten maximus (Pectinidae: Bivalvia) were followed for one year. Ovaries containing fully-grown oocytes were found throughout the year, though the degree of filling varied. Spawning activity of varying intensity occurred from late March to September. Recovery with increase in gonad index followed the spawning in spring, but there were no signs of gonad growth during a stepwise decline in gonad index from June to September. Gonad index increased to a new maximum between October and December. Oogenesis seemed to be active in filled ovaries throughout the year, and no classical resting period with empty gonads was seen. Prior to and during the spring phytoplankton bloom, recruitment of young oocytes appeared inhibited in some ovaries, leading to increased accumulation of large oocytes.

The relationship between body size and population growth rate λ has been studied in two species of opportunistic polychaetes, Dinophilus gyrociliatus and Ophryotrocha labronica, which colonize harbour environments. These species exhibit a semi-continuous iteroparous reproductive strategy, are phylogenetically closely-related but differ in body size and in some aspects of their sexuality. Ophryotrocha labronica is about 4 mm in body length, displays only slight sexual dimorphism and its sex ratio is biased towards the female sex in the ratio 2:1. Dinophilus gyrociliatus is about 1 mm in length, the males are extremely small and the sex ratio is strongly biased (3:1) in favour of the females. In spite of the considerable differences in all traits of their life histories and in many demographic parameters, the growth rates of the two populations are very similar. The analyses carried out have shown that the rapid attainment of sexual maturity of D. gyrociliatus gives it an advantage that offsets the greater fecundity of O. labronica. It is very likely that the reproductive peculiarities of D. gyrociliatus help to raise the population growth rates. The ‘saving’ on the male sex achieved both by the shift of the sex ratio in favour of the females and by the reduction in the males' body size would appear to enable D. gyrociliatus to grow at the same rate as O. labronica, a larger and more fecund species.

A new species of Hydroides (Polychaeta: Serpulidae), is described. Thirty specimens of Hydroides tenhovei sp. nov. were found on a flat PVC structure on soft-bottoms near Punta San Juanico and five additional specimens from Cabo San Lázaro, Baja California Sur, Mexico. The new species is characterized by the presence of a verticil with three large dorsal hammer-shaped spines, partially fused; basal internal spinules are absent in these spines; other spines curve outwards, with sharp tips and a basal internal spinule.

The present study was carried out during the summer of 1997 in three locations of the western Italian coast (La Spezia, Ligurian Sea; Ischia, central Tyrrhenian Sea; Ustica, southern Tyrrhenian Sea) to investigate variability in abundance and size structure of the labrid fish Thalassoma pavo along a latitudinal gradient and over different spatial scales. Fish abundance and size were estimated by visual census in shallow rocky reefs. Significant differences were detected in average abundances of T. pavo (with and without the contribution of juveniles) among locations (separated by a distance of hundreds of kilometres from each other) and over the smallest scale examined (i.e. among sites located tens of metres from each other). However, most variability was explained considering the largest spatial scale associated with the latitudinal gradient. Average abundances generally decreased from the southern Tyrrhenian to the Ligurian Sea. In terms of frequency, juveniles (<5 cm total length (TL)) increased from north to south, while the largest fish (16–20 cm) displayed an opposite trend. The intermediate size-classes (6–10 and 11–15 cm) did not show any distinct patterns. In terms of abundance, small T. pavo (0–5 cm) showed significantly higher densities at Ustica, followed by Ischia and La Spezia. Fish 6–10 and 11–15 cm long were significantly less abundant at La Spezia than at Ischia and Ustica, while those between 16 and 20 cm TL did not differ numerically among the three locations. The results of the present study provide suggestive evidence that factors acting on a geographical scale are likely to influence distribution patterns of the thermophilic fish T. pavo, although significant effects have been also observed at the smallest spatial scale examined. Climatic conditions (e.g. water temperature along the latitudinal gradient) and substrate features (e.g. macroalgal cover, physical complexity, slope) are thus likely to affect average abundances and size structures of T. pavo populations along the western Italian coast.

The ctenostome bryozoan Alcyonidium diaphanum is widespread and abundant in the coastal waters of England and Wales. It was recorded in 77–90% of beam trawl catches in the eastern English Channel and southern North Sea, and in 53–73% of catches in the Bristol Channel and Irish Sea. The maximum catch rates in these two study areas were 1410 and 751 kg h−1 respectively. Alcyonidium diaphanum was most abundant in the greater Thames Estuary. Additional data from the North Sea indicated that A. diaphanum is widely distributed throughout the southern North Sea. Alcyonidium diaphanum was found intertidally in only seven of 99 locations sampled. Several different morphotypes were observed, ranging from cylindrical to lobate forms. The distribution patterns of various morphotypes are discussed.

Spatio–temporal changes in density, breeding cycle, growth and population structure of Hydrobia ulvae (Gastropoda: Prosobranchia) were studied by monthly sampling of a wide bare mudflat in Marennes-Oléron Bay. Four stations, located along a cross-shore transect and characterized by different geomorphological structures, were investigated from March 2000 to February 2001. Hydrobia ulvae was mainly distributed in the upper half part of the mudflat and no individuals were found in the lower part. The breeding cycle extended from March to December and showed two annual peaks, in spring and in autumn. Three cohorts were recruited during the year and showed high growth rates during summer; the parameters of the von Bertalanffy model describing the growth curves were equal to kmax=0·47±0·5 mm month−1 and L∞=5·4±0·2 mm. The snail population had similar size–frequency structure along the transect at the beginning of the survey but summer recruitment initiated spatial differentiation. Reproduction occurred in the middle part of the mudflat but recruits mainly settled down at the upper level of the mudflat; new cohorts appeared with increasing individual densities. The middle part of the mudflat was rather dominated by adult individuals which showed large density fluctuations.

The relationship between shell growth rate and striae deposition was investigated in a field study in which groups of juvenile scallops, Pecten maximus, (Pectinidae: Bivalvia) were deployed for monthly periods over a year in the Menai Strait (North Wales). The number of striae deposited per day, inter-striae width (the increment of shell deposited between successive striae) and striae abundance (the number of striae deposited per mm of shell height) all correlated well with measured shell growth rates. During the winter months, when seawater temperatures were minimal (6°C), inter-striae width declined, whilst striae abundance increased, whereas during the summer when seawater temperatures were maximal (18°C), shell growth was rapid with maximum inter-striae width, resulting in a seasonal pattern of narrowly grouped, then widely spaced striae. This seasonal pattern in inter-striae width variation provides an accurate and reliable method for estimating the number of growth cycles and hence the age of P. maximus.

A geographic discrepancy between the distribution boundaries for larvae and adults of the chaetopterid Mesochaetopterus sagittarius was recorded. The most northerly position where benthic individuals, probably not reproductive, have been collected in the Atlantic corresponds to the latitude of Aveiro (Portugal). The most northerly position for larvae corresponds to that of Arcachon (France). The larvae found off Arcachon constitute an influx of subtropical origin. They rarely succeed in passing the fixation stage, and when they do, the benthic stage is not capable of reproduction. The occupation of a very large zone by planktonic larvae spread over 4° of latitude (500 km), eventually resulting in sterile benthic populations, confirms that environmental constraints are less severe on larvae than on adults. This work emphasizes, through the integration of different oceanographic disciplines, the importance of knowing the structure of the spatial distribution of adults when seeking to achieve a better understanding of local recruitment.

The life cycles of Clytia linearis and Clytia noliformis, two common campanulariids previously known solely from their polyp and young medusa stages, were investigated. Adult medusae of C. linearis have a bell diameter of 2·5–3·6 mm, and up to 29 tentacles. The bell is almost flat when relaxed and C-type microbasic mastigophore nematocysts form a cluster at the tip of the tentacles. Mature medusae of C. noliformis have a more hemispherical, saucer-shaped bell (3·5–4·5 mm in diameter), up to 16 tentacles, and no diagnostic nematocysts. Polyps of both species also differ in morphology, colour, and cnidome, and a possible resting structure is described for C. linearis. The relevance of characters from the perisarc and hydranths for taxonomy within the Campanulariidae is also evaluated, and whether the size of nematocysts is variable or not, and therefore appropriate for species identification.

Digital image analysis was applied to quantify the degradation of muscle in sea bass Dicentrarchus labrax (Pisces: Moronidae) larvae. The measure obtained was the percentage muscle fibre separation (MFS). This measurement was compared to that obtained through classical scoring. The percentage MFS classified correctly a larger number of larvae from different feeding treatments (Fed, Starved and Delayed treatments) and paralleled nutritional condition, both by age and by size. It also yielded a significant correlation with the survival of the Starved larvae. The onset of the mass mortality of Starved larvae was used to define a critical value (Mmax) of 6% MFS which would severely handicap survival. We regard MFS as a useful contribution to the determination of condition in fish larvae. It is a relatively fast quantitative method, and its use would reduce the bias caused by discrete grading (scores) and by differences in individual expertise.

Mytilus edulis, Cerastoderma edule and Aequipecten opercularis were found to ingest zooplankton when suspended in mesh cages in the water column in the Firth of Clyde. Zooplankters were also found in the stomachs of bivalves that had been taken directly from their natural habitat. The bivalves consumed a wide range of zooplankton species, but selectively consumed smaller categories of zooplankton present. Condition of zooplankton in the stomachs of the bivalves varied with zooplankton species. A degree of larviphagy was evident, particularly in Mytilus edulis.

A fragment of hedgehog was first isolated by polymerase chain reaction (PCR) from genomic DNA of Qingdao amphioxus using degenerate primers designed according to the conserved sequence in the second exon of hedgehog family. Then RT-PCR and rapid amplification of cDNA ends (3′ and 5′ RACE) were carried out using the mRNA of 18-h neurulae as template. The PCR products were sequenced and constituted a 3540 bp-long hedgehog gene, containing a complete open reading frame. The predicted protein is 415-amino-acids long, showing a high level of identity to other hedgehog proteins. The results show that Qingdao amphioxus contains one and probably only one hedgehog gene. Whole mount in situ hybridization revealed that hedgehog expressed in the prospective notochord, the notochord, floor plate of neural tube and mouth, similarly to its vertebrate homologue Sonic-hedgehog gene. This suggested that amphioxus hedgehog gene might function in the notochord induction to neural tube cells and in the development of the mouth.

Munida subrugosa was sampled monthly from November 1997 to November 1999 in the Beagle Channel by means of an epibenthic trawl. The reproductive cycle started in May, reflected by the occurrence of ovigerous females. Maximum size of oocytes, maximum value of gonadosomatic index in females (16·8 g mm carapace length [CL]−1) and males (1·6 g mm CL−1), and the proportion (∼70%) of ovigerous females with full egg-clutches occurred in June. Since the proportion of ovigerous females in October was ∼5% and the planktonic larvae reportedly hatch in September, the embryonic development lasted ∼90–120 days. Females and males attained physiological maturity at 9·9 and 8·0 mm CL respectively, and males reached morphometric maturity at 24·4 mm CL. Fecundity was correlated with female size (r=0·85) and was between 124 and 10,750 eggs per female. Average diameter of recently extruded eggs was 0·69 mm (SD±0·06 mm). At the beginning of the reproductive cycle, ovigerous females had partial broods of ∼300 eggs, which represented <5% of complete clutch.

Two species of genus Squatina were recorded off the coast of Senegal and Squatina oculata is the most commonly caught in the area. Adult males and females studied were over 820 and 890 mm total length (TL) respectively, with the largest male and the largest female recorded being 1450 mm and 1570 mm and weighed 37 kg and 39 kg respectively. The females were significantly heavier than the males. Size at birth was between 226 and 266 mm and weight at birth between 129 and 159 g. Weight of ripe oocytes ranged from 87·65 to 117·60 g (mean SD 101·73±&;8·65). Gestation lasts one year minimum. Squatina oculata is a lecithotrophic species. Counts of ripe oocytes, eggs, embryos and fully developed foetuses showed that ovarian fecundity is significantly higher than uterine fecundity. The former ranged from 8 to 20 (mean SD 12·04±5·80), the latter from 3 to 8 (mean SD 6·22±3·41). There is no relationship between size and the categories of fecundity. Adult males and females were more common than the other categories of specimens landed. Among adults, females were more numerous than males, mainly gravid specimens.

This study was conducted between January and December 1995 at Armação do Itapocoroy, Penha, Santa Catarina, southern Brazil. Monthly samples were carried out in the morning, afternoon, and evening using two over-trawls with 6 m at the opening, 3·0-cm mesh at the outer part and 2·0-cm mesh in the bag. Dardanus insignis was collected year round but with higher densities in September and October. The hermit crabs were more abundant during the evening than the afternoon but no differences were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes (<1·8 cm) while males outnumbered females in the largest ones (>2·2 cm). The individuals of this population of D. insignis have a mean cephalothoracic length of 1·89±0·40 cm (range 1·00 to 3·90 cm) and a mean weight of 40·26±27·06 g. The size distribution showed an unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Dardanus insignis showed a seasonal reproductive pattern with a peak from September to November and complete absence of ovigerous females from April to August. The von Bertalanffy growth function (VBGF) with temporal oscillation fitted for this population of D. insignis had the following parameters: L∞=4·40 cm, K=0·60, C=0·95, WP=0·35. Recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2·21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both cephalothoracic width and crab weight.

Otolith microstructure of the Russian sturgeon, Acipenser gueldenstadti was examined in adult samples collected in the Caspian Sea. The microstructure of the otolith was the same among specimens. The anterior side of the sagitta grew in two directions elongating both the long and short arms, and the long arm sections exhibited 14–21 distinct translucent and opaque zones. Otolith increments in this species can be used for age determination.

Indicator bacteria and Salmonella spp. were investigated in both Chamelea gallina and seawater from six stations on the coastline of Sile, Turkey. Studies were carried out on 15 days from June to December in 1998–1999. Chamelea gallina samples which were collected at approximately 5–10 metres depth from the chosen stations were examined for faecal coliform, Escherichia coli and Salmonella spp. Bacteria numbers were highest in July and August. Bacteria distribution was found to be statistically significant between stations. No Salmonella spp. were detected in the samples.

The effect of algal food concentration, substratum, light, salinity, cyprid density and ‘footprints’, cyprid age, films of organic biopolymers, bacteria and diatoms on the settlement of Balanus reticulatus cyprids were studied. The algal food quantity (from 7×104 to 4×105 cells ml−1) fed to nauplii had a significant effect on the settlement. Cyprids failed to settle on glass surfaces but would settle on polystyrene. Light, cyprid ‘footprints’ and age significantly affected the settlement, however, salinity (from 20 to 40 psu) and cyprid density (from 5 to 200 per 5 ml of seawater) had no effect on the settlement. Films of organic polymers, bacteria, and diatoms inhibited the settlement compared to control. It is suggested that cyprids of B. reticulatus can serve as an appropriate test material for antifouling bioassays in those areas where the former forms a dominant species.