An undescribed species of the genus Didemnum (Didemnidae) reported from installations in Whangamata Harbour (Coromandel Peninsula), has a unique and conspicuous three-dimensional growth form (possibly associated with vertical and undersurfaces it occupies). It is also distinguished by a combination of the few characters available to define these small, simplified, convergent organisms. Its stellate spicules are sparse except for a patchy layer in the surface test, primary common cloacal canals are the full depth of the zooids, nine vas deferens coils surround the testis, the gut is long forming a double loop, and larvae have six pairs of ectodermal ampullae. Eleven species said to belong to this genus have previously been reported from New Zealand, but only six are valid Didemnum spp., and they all are distinguished readily from the present species. Nevertheless, there is no evidence that the new species is introduced, and the simplest explanation of it occurrence is that it is part of the little known indigenous didemnid fauna of New Zealand.

This study has shown that the main constituents of the diet of the harbour seals (Phoca vitulina) of Dundrum Bay, County Down, north-east Ireland, during the past few years (1995–2000) have been small flatfish and gadid fish, with the emphasis shifting from the beginning to the end of the study period from flatfish to gadids, principally whiting and haddock/pollack/saithe. During both 1995 and 1996 the diet of post-weaning pups consisted almost entirely of small gadid fish. The implications of this relatively poor diet, apparently deficient in oily fish, are considered—together with information on fish stocks in the north-west Irish Sea in recent years—in the context of an apparent decline both in the breeding population of harbour seals along the County Down coast and in the play behaviour of juvenile seals.

This is the first study to examine the seasonal biochemical composition of tissues from male and female Cucumaria frondosa. Gonad and body wall tissues were analysed for their protein, lipid, and glycogen content. Lipids were the single most abundant component in gonad tissues, followed by proteins and glycogen, for both males and females. However, only protein and glycogen in the gonad tissues differed between feeding and non-feeding periods as well as between pre- and post-spawning periods. Proteins and lipids were both more abundant than glycogen in the body wall tissues. In this case, only protein and glycogen were found to differ between spawning states. All differences observed in the gonad tissues were attributed to the annual reproductive cycle, which produces a need for nutrient storage to allow the production of gametes throughout the year. The body wall was thought to be responsible for the build up of reserves during the feeding period in order to support maintenance and reproduction during non-feeding months.

Loligo gahi and Loligo sanpaulensis (Mollusca: Cephalopoda), two squid species presently under exploitation in the south-west Atlantic, are sympatric in coastal waters of northern Patagonia. In the present study, the morphometry of both species' northern Patagonian populations was analysed and compared. Relationships between the morphometric variables and mantle length, the standard measure of size for squids, are allometric in most cases. Weight and fin length show different rates of growth relative to mantle length in males and females of both species. Fin length, fin width and mantle length are the best morphometric variables to discriminate the mantle/fin complexes. Free rachis length, gladius length and gladius width are the most useful to separate both species' pens. The best discrimination of the tentacles is provided by the diameter of the central and marginal suckers and the number of teeth on the three largest sucker rings. Discriminant functions are provided to allow the classification of individuals from both species and the identification of pens and tentacle clubs found in predators digestive contents.

Body volume was measured directly by the water displacement method and using three different geometric models, consisting of a series of cones and truncated cones, in California sea lion (Zalophus californianus) pups from the Gulf of California. Volume is required for the estimation of density, an indicator of the ratio of fat to lean mass. A model consisting of two cones and four truncated cones predicted body volume with greatest accuracy (volume=1·11+1·06&;estimated volume, r2=0·90, P<0·001, SEE=0·673, N=274). This model, however, was not adequate to estimate absolute pup body density (mass to volume ratio), as it yielded values poorly correlated with observed body density (r=0·14, P=0·02). However, the regression line of mass on volume indicated that density decreased with volume, so the mass to volume ratio is a biased estimate of density and is not appropriate for comparing whole body density among sea lion pups. The direct analysis of the relationship between body mass and body volume (observed or estimated) through analysis of covariance provided a better tool to compare the relative density among pups of different sex, populations, or born in different years. The results from such analyses are consistent with previous evidence of sex and age effects on body composition.

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.

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.

The death assemblage of molluscs (gastropods and bivalves) from the sandy beach at Harlyn Bay, north Cornwall is shown to be fully representative of the biodiversity of the regional species pool from all habitat types. The biodiversity measures used are average taxonomic distinctness (Δ+, the average degree to which species in an assemblage are related to each other) and variation in taxonomic distinctness (Λ+, the evenness of the spread of taxa across the taxonomic spectrum). A late Pliocene fossil assemblage of molluscs from St Erth Pits, north Cornwall, UK, is also not significantly different in biodiversity, in these terms, from the present-day regional species pool. The climate in the late Pliocene was similar to the present-day Mediterranean, suggesting that predicted changes in climate, by the end of this century, will not affect molluscan biodiversity, although the species composition will undoubtedly change.

The sulphur compound composition of the hydrothermal vent mussel Bathymodiolus azoricus (Bivalvia: Mytilidae) was analysed in order to determine the specific biochemical characteristics of a thiotrophic mode of nutrition. In specimens collected from two contrasting vent fields on the Mid-Atlantic Ridge (Menez Gwen and Lucky Strike), substantial differences in the sulphur composition were observed between tissues and sampling sites. Total sulphur content was higher for samples from Lucky Strike than for those from Menez Gwen. The amount of elemental sulphur in the gill of B. azoricus was in the same range as values previously reported for the vesicomyid clam Calyptogena phaseoliformis and the lucinid clam Lucinoma annulata. Rings of orthorhombic sulphur or compounds such as polythionates or organopolysulphides excreted in the cytoplasm by the symbionts may account for the large amounts of elemental sulphur evidenced for the first time in an hydrothermal vent mussel. A large proportion of the tissue-sulphur was incorporated into free amino compounds such as taurine, hypotaurine, thiotaurine and cysteine, and in a lesser extent to the tripeptide glutathione. In mantles, sulphur seems to be contained mainly in organic compounds such as proteins, mucopolysaccharides and lipids. However, the occurrence of specific compounds such as thiotaurine and elemental sulphur in gills indicate that in this tissue a large proportion of the sulphur might be involved in specific pathways related to transport, storage and detoxification of sulphide. Moreover, our results suggest a greater reliance on thiotrophy of mussels from Lucky Strike as compared to specimens from Menez Gwen.

Data from bottom trawl surveys conducted each summer, winter and spring on the Cretan shelf from 1988 to 1991, were used to study the age, growth, maturity and bathymetric distribution of red pandora (Pagellus erythrinus). The good agreement of back-calculated and observed lengths-at-age with length frequencies and the marginal increment analysis, supported the annual nature of scale marks. A comparison of available growth data from the Mediterranean and the Atlantic revealed higher lengths-at-age for red pandora in the north-western Mediterranean and the Atlantic than in the central and eastern Mediterranean. The auximetric analysis, i.e. the double logarithmic plot of the parameter K of the von Bertalanffy growth function vs asymptotic length (L∞), showed a strong negative relationship for the central and eastern Mediterranean data set, implying a common ‘growth space’ for the populations in these areas. Lengths-at-maturity were lower on the Cretan shelf than in the Atlantic. These differences were attributed to the synergistic combination of trophic and thermal conditions.  Depth, temperature and salinity data were combined with biological data on abundance, fish size, age and maturity. In general, mean size increased with bottom depth because smaller individuals tended to be found in shallower and warmer waters. Individuals having reached first maturity were mainly distributed in the periphery of the algal/angiosperm meadows (60–80 m). All detailed studies of the bathymetric distribution and movements of shelf-dwelling demersal species (Mullus barbatus, Mullus surmuletus, Lepidotrigla cavillone and Pagellus erythrinus) in the Mediterranean show that these species are characterized by a spring–summer spawning season, a high concentration of spawning adults at mid-shelf depths, and nursery grounds located in the vegetated shallows. This multispecies pattern might have an adaptive function with both ecological and management implications.

The effect of sponge encrustation on swimming ability of Chlamys hastata was determined by investigating swimming behaviour, scallop morphometry, and energy expended during swimming with and without commensal epibionts. Scallops swam significantly longer after sponge encrustation was removed from their shells, but no significant differences were detected in swimming elevation or distance. Scallops with sponge encrustation showed no adductor muscle hypertrophy or changes in shell morphometry compared to scallops without encrustation. However, C. hastata did exhibit scaling relationships associated with maximizing swimming efficiency. Specifically, shell width and adductor muscle mass were positively allometric with shell height, while shell mass was negatively allometric with shell height. Scallops increased their energy expenditure (both aerobic and anaerobic) during valve-clapping, but no significant difference was detected between unencrusted (43·0 μmol adenosine triphosphate [ATP] consumed during a two min escape swim) and sponge-encrusted (40·0 μmol ATP) scallops. Scallops in both treatments derived 86% of the energy used for swimming from anaerobic sources. The lack of substantial differences between scallops with and without commensal sponges is partially explained by the observation that even heavy sponge encrustation increases the immersed weight of the scallop by only 5%. The presence of a sponge encrustation does not appear to inhibit swimming by this scallop species.

An inexpensive and easy to build and deploy device to measure immersion times is described. The device consists of an LCD timer mounted in a small waterproof PVC housing. Time is recorded and integrated when seawater creates a connection between two stainless steel contacts. The device was tested in the laboratory and under field conditions on a wave swept shore. Under laboratory and field conditions, the device gave precise estimates of immersion times with maximum error of less than 4%. Applicability of this device in ecological and physiological studies is discussed and compared to other methods proposed in the literature.

Sea urchins were collected in August 1999, at Salvador (Todos os Santos Bay, State of Bahia, Brazil). Twenty out of 20 Eucidaris tribuloides sea urchins studied had sponge remains in their guts, 12 of which, in large enough quantities to discard the hypothesis of sponge contamination on other food items. No other macroscopic evidence of alternative food sources has been encountered. Sponges found in large enough quantities were classified in seven genera, spread over seven families and five orders of the Demospongiae. Among the commonest sponges were Haliclona spp. and Iotrochota birotulata. The results show clearly the spongivorous habit of E. tribuloides at the studied site.

The first record of a bivalve-inhabiting hydrozoan Eugymnanthea inquilina was found in Thermaikos Gulf, north Aegean Sea, eastern Mediterranean Sea, associated with Mytilus galloprovincialis. Analyses of biometric data point the same biological differences between the Mediterranean and the Japanese Eugymnanthea, as reported by previous researchers.

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.

The full developmental embryonic sequence of Gobius cruentatus is described for the first time. Embryonic development lasted 13 days (14·0–15·0°C). The newly hatched larvae (3·3 mm total length) presented pigmented eyes, the yolk is fully absorbed, and the mouth and anus were opened allowing the onset of exogenous feeding almost after hatching.

Arsenic compounds in aqueous extracts of muscle, liver, kidney, and lung tissue taken from a sperm whale Physeter catodon (Mammalia: Cetacea) beached on a small island near Phuket in the Andaman Sea were determined by high performance liquid chromatography using an inductively coupled plasma mass spectrometer as the arsenic specific detector. The total arsenic concentrations in the tissues (dry mass) were low, ranging from 0·3 μg g−1 for liver and lung, to 1·0 μg g−1 for muscle and 3·0 μg g−1 for kidney. Most of the arsenic (>60%) was extracted from the tissue into water, and the bulk (>80%) of this arsenic was present as arsenobetaine. Dimethylarsinate was present at low levels in all four tissues whereas arsenocholine was detected in kidney, liver and lung, but not in the muscle tissue. Another arsenic containing betaine, trimethylarsoniopropionate, was also present in all four tissues. This is only the second report of trimethylarsoniopropionate as a naturally-occurring arsenic compound.

The relationship between the increase of the sea surface temperature observed off the Galician coast and the appearance of a tropical poikilotherm species Argonauta argo in these coasts is discussed. This is the first record of Argonautaargo in the north-west Iberian Peninsula. A female of this species was captured alive near the surface at dusk on 22 December 2000 in the Ria de Aldán (42°15′N–08°48′W). The specimen, a mature female of 70 mm mantle length and 96 mm shell diameter, died 36 hours after introduction in the tank.

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 short-term variability of intertidal microphytobenthic biomass was characterized by analysing a 30-day time series encompassing two spring–neap tide cycles. Chlorophyll-a concentration was measured every day at the beginning and at the end of every diurnal exposure periods. Microalgal biomass exhibited predictible net increases during diurnal exposures due to a positive production-loss balance. In addition, our data series shows that after an environmental disturbance, even though biomass decreased strongly, it converged quickly back to its initial steady-state oscillation pattern. This study supports some fundamental properties of the dynamics of microphytobenthic biomass, as previously predicted in our mathematical model of primary production.