Variation in morphological characters seen in a large collection of specimens of the genus Echinosigra from the Rockall Trough can be arranged in a continuous ontological series. This growth series embodied forms agreeing with Mortensen's (1907) descriptions of both E. phiale and E. paradoxa. Bivariate biometrical study showed a well-defined allometric relationship of test length to other body dimensions, particularly the width of the ‘head’ and the width and height of the ‘body’. Immature specimens corresponded to E. phiale whilst the typically elongated ‘neck’ of adults corresponding to E. paradoxa was developed, along with the opening of the genital pores, at around a test length of 20–24 mm.

Coccolithophores and Parmales are important functional groups of calcified and siliceous marine nanophytoplankton. Large-scale biogeographic distributions of the two groups were investigated based on 71 samples that were collected in the Atlantic Ocean. Using a scanning electron microscope, a total of 48 taxa of coccolithophores and eight taxa of Parmales were recorded, with Emiliania huxleyi, Tetraparma pelagica and Triparma strigata as the predominant forms. The highest abundances of coccolithophores (376 × 103 cells l−1) and Parmales (624 × 103 cells l−1) were observed in waters north-east of the Falkland Islands and the South Georgia Island, in close association with the Subantarctic Front and Polar Front, respectively. Three major biogeographic assemblages, i.e. the Falkland Shelf Assemblage, the Southern Ocean Assemblage and the Atlantic Ocean Assemblage, were revealed in cluster analysis. Additionally, canonical correspondence analysis indicated that temperature significantly affects the latitudinal patterns of the two algal groups. High abundances of Parmales were closely coupled with those of E. huxleyi in waters of the Southern Ocean with low temperature (<10°C). However, the number of coccolithophore species, along with the Shannon–Weaver diversity, significantly increased with elevated temperature, suggesting more diverse assemblages in tropical waters.

The present study describes the morphological changes of the mouthparts and foregut of the freshwater prawn M. acanthurus that occur during the development of the larvae and first juvenile. The results indicate that the zoeae I have mouthparts with reduced setae and a structureless foregut that indicates obligatory lecithotrophic behaviour. There is an increase in the number of setae in these structures between the zoea II and the juvenile stage, indicating the adaptation of the organism for feeding. More complex structural alterations were observed in the first juvenile, which acquires benthonic habits, which ensure the capture and ingestion of a diversity of feeding resources found in the substrate.

The stomach of Decapod crustaceans is a complex structure with great interspecific variation. Several studies suggest that the anatomy of the gastric mill varies according to the diet of species in different groups. An alternative view suggests the gastric mill's structure is related to phylogenetic aspects rather than to the diet of a species. The morphology of the gastric mill of Ovalipes trimaculatus, a portunid crab target of fisheries in Argentina and Chile, was studied through stereo-microscope and scanning electron microscope images. Ovalipes trimaculatus has a stomach that corresponds to a macrophagous and predatory diet. The gastric mill is similar to that of other portunids, especially those with predominant animal component in their diet. Our results support the idea that this structure has a basic pattern, given by shape and elements forming the gastric mill; and upon that pattern, trophic habits adaptively shape certain traits.

Early life traits (ELT) of the sand-burrowing cryptic marine fish Sindoscopus australis (family Dactyloscopidae) were compared between cohorts hatched during winter and spring 2013, in nearshore rocky reefs off central Chile. Pelagic larvae were similarly abundant during both periods, but larger larvae were collected during austral spring. The sagittal otolith microstructure and size analyses also indicated that size-at-hatch was larger (4.7 mm) for the winter cohort, but winter larvae experienced slower growth rates (0.145 mm day−1 ± 0.008). Conversely, larvae from the spring cohort hatched at smaller sizes (2.9 mm), but they grew faster (0.182 mm day−1 ± 0.008). Hatching periods were coupled with the lunar cycle; in winter, hatching events were related to neap tides (first and third quarter moon), increasing chances of self-recruitment. Meanwhile, during spring, hatching occurred during spring tides, particularly over the new moon, decreasing chances of larval mortality by predation. Otolith traits used to test asymmetry among cohorts showed inconsistent results. Only sagittal perimeter presented fluctuating asymmetry, showing higher variance for the winter cohort. We conclude that this burrowing species displays different reproductive tactics at a seasonal scale.

This brief review discusses the different ways in which the study of gelatinous plankton has contributed to an understanding of the physiology and evolutionary relationships of other animals.

The present paper investigates standing stock variations of Halimeda opuntia on a sandstone reef of the South-west Atlantic Ocean, in order to better understand the role of this seaweed as a CaCO3 producer. The study was conducted over two 3-month periods, using photo quadrats to analyse the coverage area, and destructive sampling to quantify area-specific biomass and CaCO3 percentage. The alga occupied 2.4% of the substrate (4464 m2), growing as clumps with an average biomass of 1.59 kg m−2, resulting in a standing stock of 7097.8 kg of alga. This standing stock varied with environmental conditions, particularly wind speed. Assuming an exponential model for these variations, H. opuntia produced at least 13,050.14 kg (54.37 g m−2 day−1) of carbonate sediments. There was a positive correlation between changes in standing stock and coverage, but not with area-specific biomass. This suggests that net algal growth results in the occupation of new spaces, with minimal increases in height or segment density. Therefore monitoring coverage should complement traditional individual-based methods for estimating Halimeda growth and production. Combined, these approaches should result in more accurate models of the role of this alga on marine carbonate budgets.

This is the first study of the metabolic enzyme activity and energy state of the dwarf oyster Ostrea stentina (Payraudeau, 1826) in Tunisia and in the Mediterranean region. The main purpose of this study was to examine the modulation of the physiological status of the oyster O. stentina depending on the season and the presence of parasite Marteilia refringens. The prevalence of bonamiosis and marteiliosis were established by PCR. Bonamia exitiosa was detected only in 2.91% of oysters while the prevalence of M. refringens was 100% (30 Ind./30) in February and 93.93% (28 Ind./30) in March. A 42–87% mortality rate was reported during the study period. Biochemical analyses were carried out to evaluate the management of the energy resources in regard to the biochemical changes of lipids and carbohydrates. The enzyme activity of pyruvate kinase (PK), citrate synthase (CS) and cytochrome c oxidase (CCO) were measured and the mean level of enzyme activity was respectively 20.31 mU mg−1 protein; 12.06 mU mg−1 protein and 3.59 mU mg−1 protein. Carbohydrate contents of O. stentina were very low all year round with an average of 15.18% in dry weight, and lipid contents remain similar (11.77% in dry weight) compared with the values reported for most other temperate bivalves. Enzyme activity significantly decreased over time (P < 0.001). The energy resources of the oyster O. stentina wherein much of the energy was devoted to reproduction seem to affect the defence system.

Cultivation of the geoduck Panopea zelandica (Quoy & Gaimard, 1835) requires knowledge on embryonic development to produce spat in hatcheries. This study investigated the development of P. zelandica embryos at 15°C and 35 ppt and the optimal sperm:egg ratios for fertilization under hatchery conditions. Panopea zelandica broodstock were induced to spawn by serotonin injection. Sperm and eggs were collected and fertilization was conducted at sperm:egg ratios of: 50:1, 100:1, 500:1, 1000:1 and 10,000:1 over 40 min. The optimal sperm:egg ratio was <500:1 and the normal embryo yield at 3 and 18 h post-fertilization (hpf) ranged from 83–96%. Panopea zelandica eggs (~80 μm diameter) developed the first and second polar bodies within 15–20 and 50–55 min post-fertilization, respectively. The blastula appeared at ~8 hpf, including the XR and XL cells and the presumptive shell field depression. Gastrulation occurred at 12–18 hpf with organic material apparent at the shell field depression. The mid-stage trochophore, which appeared at around 35 hpf had an apical plate with an apical tuft. The shell field spread to form the periostracum, which expanded and folded into right and left segments covering the late trochophore. The early D-stage veliger appeared at 45 hpf with the soft body being enclosed by two valves and the appearance of the velum. These observations will serve as the basis for future analyses of P. zelandica embryogenesis and for optimization of commercial production of D-veliger larvae.

specimens of the zipper sand skate psammobatis extenta were collected in the region of ubatuba off the northern coast of the state of são paulo, brazil, monthly for one year (january–december 2000), at 25- to 40-m isobaths. a total of 123 individuals were caught. the total length (tl) of females averaged 224.6 mm, and of males 217 mm. the overall sex ratio was 1:1. analysis of the length–weight relationship indicated the existence of positive allometry in females, and isometry in males. the length at onset of sexual maturity was determined for both sexes; females reached sexual maturity at smaller sizes than males (tl50=230.7 and tl50=237.7 mm respectively). females showed functional parity of both ovaries and uteri. females that were pregnant or were carrying vitellogenic oocytes were observed during nine of the 12 months of the survey, indicating a continuous reproductive cycle. psammobatis extenta was most abundant from january to april, and again from june to october. most individuals were collected at the 40-m isobath. both adults and neonates were collected in the study area. however, adolescent skates were scarce, which either indicates differential occupation of the area, or suggests that the shallow waters of the continental shelf are used as breeding grounds.

Detailed sampling of the bottom water of Christchurch Harbour, England, was undertaken in conjunction with a study of the living and dead foraminiferids (to be described later). The Harbour is a shallow estuary with an unusual tidal regime of four high tides daily. During the winter the flow of fresh water from the rivers prevents sea water from entering much of the estuary. During the spring, summer and autumn, when drier conditions prevail on land, the sea enters the estuary as a salt wedge and there is pronounced salinity stratification. In addition to determinations of chlorinity, pH, dissolved oxygen and temperature, analyses of calcium were made during the spring, and of calcium and magnesium in the summer. It was found that calcium was preferentially removed from the bottom water, thus upsetting the calcium-chlorinity ratio. The cause of the calcium removal is thought to be biological activity. Magnesium was not affected by this process. A discussion of the results is presented and it is suggested that biological removal of calcium from the bottom water is particularly well developed in Christchurch Harbour owing to the extensive areas of shoal water favouring biological activity. Estuaries of this type may not be very common.

The notes collected in this paper are a continuation of earlier observations on British and Norwegian hydroids and their medusae. The observations were made at the Biological Stations of Herdla (Bergen), Millport and Plymouth.

Juveniles of 33 non-resident fish collected in three sheltered shallow coves (eastern Adriatic) fell into three groups: (a) occasional (10 species); (b) present in the study site only for short periods and at small sizes, in transit to a nearby Krka Estuary (11 species); and (c) species that spend most or all of their juvenile phase in sheltered coves (12 species). This note provides suggestive evidence that shallow water habitats inside sheltered coves could play an important role as nurseries for fish groups (b) and (c) during their early life stages.

Circumstantial evidence of mobility by the lepadomorph barnacle genus Pollicipes in the literature is supported by observations at Menai Bridge which indicate that the phenomenon is real. Although slow, movement may be in response to gravity, as a positive taxis, or light, as a negative taxis.

The following is a preliminary account of some experiments carried out this summer at Plymouth. They were undertaken with a view to the investigation of the changes, both physical and chemical, which are induced in the egg by the entrance of a spermatozoon.

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.

Near-shore benthic sediment samples collected at low tide from the western Atlantic Ocean (Sable Island, Nova Scotia, Canada) and the eastern Pacific Ocean (Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada) were searched for little-known species of the rhizarian (Cercozoa) genera Pinaciophora, Rabdiaster and other related rotosphaerids. Several representatives with complete investitures of silica-scales (the structure of which is taxonomically diagnostic) were studied by transmission and scanning electron microscopy. The validity of the genus Pinaciophora (sensu Penard, 1904) as defined by a single type of plate-scale only, was strengthened by the discovery of Pinaciophora rubicunda and of another previously undescribed entity, both of which lacked spine-scales. Several earlier reports of loose scales from marine habitats, and erroneously identified as the freshwater P. fluviatilis, might be assigned to P. marina sp. nov. The new genus Thomseniophora was erected to include all ‘Pinaciophora' previously known to produce spine-scales and seven new taxa were described. Six other little-known species of Thomseniophora, Pinaciophora and Rabdiaster were described from the Canadian west coast (Pacific Ocean) including one new species of Pinaciophora. The addition of Thomseniophora brings the number of genera assigned to the Rotosphaerida to six: Pinaciophora, Thomseniophora, Rabdiaster, Rabdiophrys and Pompholyxophrys. The presence of several apparently closely related taxa in the same collection (same location and sampling date) strengthens the conclusion that relatively small differences in the morphology of their siliceous scales were more likely caused by genetic differences than by environmental influences.

Cirratulus dollfusi Fauvel, 1928 is re-described from the material from the Sea of Marmara. The specimens collected from the Sea of Marmara were compared to the holotype of the species. The species is a multitentaculate and multibranchiate cirratulid; it differs from all other known cirratulid genera in its type of chaetae and the way the multiple branchial filaments arise from the notopodia. Chaetae are of two types: numerous long, fine capillaries in both rami throughout, also 2–4 shorter, wider, finely tapering spines in noto- and neuropodia. There are no slightly flattened sigmoid spines, typical of most Cirratulus species. Very short, slender grooved tentacles arise in a small circular group on either side of chaetiger 1. Branchial filaments are multiple; they arise as 1–2 filaments from each of 4–8 raised notopodial lobes on parapodia of anterior and middle segments, with lobes fading out and fewer (holotype) or no branchiae posteriorly (our material). No other cirratulid genera appear to have straight, tapering spines plus so many fine capillaries. We propose Fauvelicirratulus gen. nov. for this species. The species seems most closely related to Cirratulus hedgpethi Hartman, 1951, from the northern Gulf of Mexico, still only known from the incomplete original description. Features of some cirratulid genera are compared and the use of multiple branchiae as a generic character is discussed.

Biomass measurements (AFDW) of both subtidal and intertidal macrofauna of the ‘Abra de Bilbao’ embayment were used within a pilot study in a four step strategy of analysis, which consisted of: (1) representing communities; (2) discriminating sites or conditions; (3) determining levels of ‘stress’; and (4) linking to environmental variables. Univariate (number of species, diversity indices) as well as multivariate (clustering, MDS, SIMPER, BIO-ENV) techniques from the PRIMER package were employed. Several data aggregation levels were proposed in the analyses with the aim of selecting cost-effective procedures. The results suggested a good integration of environmental conditions by subtidal samples, which were close to constant on all different taxonomic aggregation levels. The abiotic parameter which best ‘explained’ the biotic pattern of subtidal samples in the investigated area was turbidity measured as total suspension solids and nephelometric units on the water surface. In conclusion, we recommend monitoring rocky substrates by using more extensive biomass sampling surveys of subtidal areas followed by a less time-consuming treatment of the samples (identification by high taxonomic categories or by trophic groups).