Sea urchins are key herbivores in many coastal ecosystems. The purple sea urchin, Heliocidaris erythrogramma, is widely distributed across temperate Australia where it exhibits considerable plasticity in feeding behaviour and ecophysiology. In this study we examined H. erythrogramma populations on subtidal reefs along ~4° of latitude in south-west Australia. We used a multi-factorial survey design to assess variability in H. erythrogramma abundances between locations (>200 km part), sites (≥1 km apart) and habitat types (reef flats and slopes). We also examined spatial variability in urchin size, condition (measured by gonad index), and the relative abundances of two co-occurring subspecies. Urchin densities were generally low and did not vary between locations, but did vary between habitat types and amongst sites. Site-level variability in urchin size and condition was also pronounced. The southernmost population comprised smaller individuals and greater relative abundance of the H. e. erythrogramma subspecies, which is abundant on the east coast of Australia. We observed no indication of population-level responses to a recent extreme warming event that impacted the wider ecology of the region, but further investigation into the effects of both gradual warming and short-term climatic events on the ecology of H. erythrogramma and other key herbivores is required.

A humoral immune response was elicited in adult dogfish by intramuscular injection of keyhole limpet haemocyanin (KLH). The antibody raised to this antigen was measured by an agglutination technique. The antibody-containing fraction of the serum was isolated in a two-step procedure utilizing gel nitration on Sepharose 6B and slab gel electrophoresis. A rabbit antiserum was then raised to the purified immunoglobulin. Further gel filtration studies revealed that the anti-KLH agglutinating activity was restricted to a highmolecular-weight serum fraction (approximately 800000) in fish immunized for up to 18 months. No anti-KLH precipitating activity was detected in fish at any stage of immunization; however immunodiffusion studies with the rabbit antiserum raised against dogfish antibody confirmed the existence of an 800000 molecular weight form and also a lighter species weighing 160000 daltons in both normal and immunized fish. The antigenic specificity of this latter molecule was not demonstrated. Immunoelectrophoretic analysis of the antibody revealed a neutral/slight anodic mobility, and after reduction and alkylation the presence of two polypeptide chains weighing 18200 and 75 860 daltons was demonstrated by thin-layer gel chromatography. These physicochemical characteristics make dogfish antibody analogous to mammalian immunoglobulin M (IgM).

Despite the increase in the number of deep-sea studies, little is known about the hadal molluscs. For Brazil, only a few studies have treated the Septibranchia. This contribution is part of an effort to increase the knowledge of this group off the Brazilian coast, although it is focused only on the Campos Basin (22°S), State of Rio de Janeiro. Four species of the family Verticordiidae are recognized here. For Spinosipella tinga Simone & Cunha, 2008, the known depth distribution is extended to 1050 m. For Verticordia woodii Smith, 1885, previously reported from Brazil, the known distribution is extended southwards to the Campos Basin. Verticordia quadrata Smith, 1885, is reported from Brazil for the first time. A previously unknown species, Verticordia ouricuri sp. nov., is described. The presence of small spines, typically with a hexagonal column and a stellate structure at their distal end emerges as an additional taxonomic character for the verticordiids.

Nucella lapillus and Littorina littorea afford examples of turbinately coiled shells with no space between the columella and the inner face of the whorls. Three constants are sufficient to determine the form of such shells: λ, the ratio between diameters of successive whorls; β, the semi-apical angle and ρ, the ratio of aperture length and breadth in the apertural plane passing through the axis. The variation of these three constants with size was examined and shown to be relatively small and insignificant in Nucella, but in Littorina it was significant.

For Nucella and Littorina these shell characteristics were used to relate for the nth whorl, the length along the shell spiral (ln) to the shell height (Hn), the latter being the measure usually employed in growth studies. This relation was derived mathematically and confirmed empirically as

where α is the angle of the logarithmic spiral given by α = tan−1 2π sin β/loge λ. The increased resolution of the micro-growth band increments, which are measured along the shell spiral was directly related to the ln:Hn ratios.

Since the formula for the ln/Hn ratio (= shell conversion factor) includes λ, β and ρ, the three constants necessary to determine shell form in turbinately coiled shells of the type described, the shell conversion factor may be a better index of shell shape than indices based on a single constant. In species where the shell grows isometrically this ratio will remain constant, whereas changes in shell shape with size will influence this ratio. Such changes in shell shape during growth can be quantified in terms of the shell constants and when included in calculating the shell conversion factor, will show the relative magnitude of shell shape changes brought about by growth. The shell conversion factor may also be used to study the effects of ecological variations on the geometry of the shell.

The conical shell of the limpet, Patella vulgata, is geometrically a much simpler system in which direct shell measurements were used to relate length along the direction of maximum growth to the antero-posterior diameter of aperture.

Marine gastropods are consumed worldwide due to their nutritional quality, having important economic value in international markets. In the gulfs of Northern Patagonia (Argentina), marine gastropods are captured as complementary resources during bivalve artisanal fisheries. In this study, we determined the biochemical composition during the reproductive cycle of four edible marine gastropods abundant along the South-western Atlantic coast: Odontocymbiola magellanica, Buccinanops deformis, Buccinanops cochlidium and Trophon geversianus. All the studied species presented high protein (36–70.8%), low lipids (0.02–1.50%) and intermediate glycogen content (3.22–14.08%). The main oviposition season was during spring and summer. The mean nutritional values indicate that the species studied provide a good source of nutrients appropriate to the human diet, reaffirming their value as a commercial resource. Taking into account the nutritional contribution and the reproductive season, the best period for the capture of these resources is during summer for O. magellanica and T. geversianus, and during autumn for B. deformis and B. cochlidium. This work will help promote the consumption of Patagonian gastropods while ensuring their responsible capture, contributing to the sustainability of these valuable resources.

Females of the new species Exrima walteri sp. nov. were found in sediment trap samples deployed over different sites of the East Pacific Rise (13°N) at 2600 m depth. Four traps were deposited during the HOPE99 cruise (1999) and recovered during the AMISTAD (1999) cruise on the research vessel ‘L'Atalante’. The new species is distinguished from congeners, E. singula Humes, 1987 and E. dolichopus Humes, 1987, by the following derived characters: first somite of the urosome with 3 (one dorsal and two lateral) stout conical extensions; distal endopodal segment on the swimming leg 4 broad. In addition, many specimens of copepodids I and lecithotrophic nauplii, identified as belonging to Dirivultidae gen. sp., were found in the samples of all sediment traps. This is the first record of copepodids I and of a nauplius of dirivultids from the Pacific Ocean. Study of type and additional material collected during different Ifremer cruises at different vent sites (HERO91, EXOMAR, PHARE and MoMARETO) required synonymy of four species of Aphotopontius Humes, 1987, Stygiopontius Humes, 1987 and Rhogobius Humes, 1987. Aphotopontius rapunculus Humes and Segonzac, 1998 is transferred to the genus Rhogobius because it possesses all presumed derived attributes of this genus: last abdominal somite with lobes at sides of anal operculum; second segment of antennal endopod elongate and slender. A new study of the type material suggests that: Aphotopontius temperatus Humes, 1997 is a synonym of A. atlanteus Humes, 1996; Stygiopontius lumiger Humes, 1989 is a synonym of S. sentifer Humes, 1987 while S. bulbisetiger Humes, 1996 is a synonym of S. pectinatus Humes, 1987. Females of the three synonymized species were found to be sub-adult females at copepodid V. Leg 6 on these specimens is one seta located dorsolaterally on the posterior part of the genital somite. This position for leg 6 is unknown for copepodid V of other siphonostomatoids whose leg 6 is located ventrally at copepodid V; the dorsolateral position is presumed derived and shared by the dirivultid genera Aphotopontius Humes, 1987 and Stygiopontius Humes, 1987. A new key to the Dirivultidae genera is presented.

Results from the Continuous Plankton Recorder (CPR) Survey have been used to extend the observation by Boalch & Harbour (1977 a) of the occurrence in January 1977 of a diatom Coscinodiscus nobilis (Grunow), new to British waters. Samples have been taken by the CPR to the west of the British Isles since 1948 and along the English Channel since 1957. C. nobilis was not identified until the spring of 1977, thus confirming the observations by Boalch & Harbour. It reappeared in 1978 when it was found further north in the Irish Sea.

This study was carried out in order to provide basic information on the population ecology of the crab Sesarma rectum in the Ariquindá River mangrove, Tamandaré, State of Pernambuco, Brazil. The population was analysed with regard to the following aspects, in particular: the size-class frequency distribution of carapace width (CW), mean body size (CW) of males and females, morphological sexual maturity, sex-ratio, reproductive period, and recruitment. Samples were collected monthly from April 2008 through to March 2009; the crabs were collected manually, with a capture effort by one person for 30 minutes, during low tide. The specimens obtained were measured for CW, length of the propodus of males, and abdomen width of females; and the sex and ovigerous condition were noted. Altogether, we obtained 511 specimens (132 juvenile and 137 adult males, and 171 juvenile and 71 adult females, of which 32 were ovigerous). The median CW of males (16.15 mm) was significantly larger than that of females (13.82 mm) (P < 0.05). The size at morphological sexual maturity was 15.73 mm in males and 16.71 mm in females. The sex-ratio for the total of specimens analysed was 1.11:1 (male:female) (P > 0.05). The sex-ratio by size-class showed an anomalous pattern, with a greater abundance of males in the larger size-classes. The reproductive period was continuous and the highest frequency of ovigerous females was recorded in the spring and summer. The major pulse of recruitment occurred during autumn and winter, which is related to greater reproductive activity during the warmer months of the year.

We examined the benthic macroinfauna at three strata during two seasons (winter and summer) on two sandy beaches (dissipative and reflective) in south-eastern Brazil. The hypothesis raised is that effects of morphodynamics and zonation determine the structure of macroinfauna, with dissipative beaches having comparatively higher species richness and density than the reflective beaches. Flamengo beach (dissipative) had higher species richness but lower density compared to Grumari beach (reflective). A high dissimilarity in assemblage structure (91.75%) was detected between the two beaches. Zonation in the occurrence of macroinfauna was detected for the two beaches in the two examined seasons. At Grumari beach, Emerita brasiliensis occurred mainly in stratum 1 (intertidal swept zone) while Saccocirus sp. occurred in stratum 2 (infralittoral at 0.5 m depth), whereas at Flamengo beach E. brasiliensis and Enoploides sp. had the highest density in stratum 1 (intertidal swept zone) whereas Scolelepis goodbodyi and Donax uncinata dominated in stratum 3 (infralittoral at 1.0 m depth). Scolelepis goodbodyi, Dispio uncinata, Enoploides sp., Nematoda and Trileptium sp. were associated with higher a Dean parameter and content of organic matter at Flamengo beach. In contrast, Hastula sp., Donax sp., Pisionidens indica, Hemipodus californiensis, Saccocirus sp. and Phyllodocidae were associated with the higher wave period and grain size of Grumari beach. The hypothesis that macroinfauna structure differs between the beaches and strata was confirmed, with the dissipative beaches having comparatively higher richness but lower density than the reflective beaches.

Changes in the intracellular free amino acid (FAA) concentrations of Tigriopus brevicornis when subjected to hypoosmotic (5 psu), normal seawater (35 psu) and hyperosmotic (70 psu) conditions for a three day acclimation period were investigated. Proline, alanine and lysine were the major contributors to the intracellular FAA pool. Under hypoosmotic conditions, alanine was the dominant osmolyte with proline concentration at its lowest. This trend was reversed under hyperosmotic conditions. However, the total FAA pool was at its highest concentration under normal seawater conditions, with the total FAA concentrations being reduced during hypo- and hyper-osmotic conditions.

The evidence for variations in winter phosphate concentration as a component of the ‘Russell Cycle’ has been re-examined. The change from high phosphate concentrations prior to 1930 is the largest apparent variation in concentration through the period 1923–1987. However, these values are the result of a retrospective application in 1938, of a salt correction factor of 1–35. The justification for this factor is examined. It is concluded that there is sufficient uncertainty in the accuracy of the pre-1948 measurements of phosphate concentration to preclude their use in long time-series analysis. A statistical analysis of the post-1948 data shows that a simple first order autoregression model provides a perfectly adequate description of the data; the data can be considered as essentially random, with a small component of carry over from one year to the next. The evidence is weak that variations in winter concentrations of phosphate support the Russell Cycle hypothesis.

Four species of Pisionidae (Polychaeta) are reported from Coiba National Park (Pacific, Panamá), one is a well known species of the area Pisionidens indica, one is a new species of Pisione and there are two new reports: Pisione galapagoensis and Pisione cf. papuensis. Pisione longispinulata sp. nov. possesses buccal aciculae distally elongated with a conspicuous notch, three compound chaetae per parapodium, with dense and long spines on margins, and a single pair of copulatory organs, each with modified ventral cirrus, distal spherical enlargement and distal papillae. The closest species is Pisione garciavaldecasasi, also from the Coiba National Park, although it lives in freshwater streams in the northern part of Coiba Island.

The land crab, Discoplax celeste (Gecarcinidae) is endemic to Christmas Island in the Indian Ocean. Due to a freshwater-dependant life history, in which the megalopae migrate from the ocean up freshwater streams to their adult terrestrial/freshwater habitat, D. celeste inhabits only a few isolated locations on the island. This restricted distribution is one of a number of factors which has previously highlighted the vulnerability of this species to outside threats. A number of anthropogenic factors including the introduction of multiple invasive species and habitat destruction have led to drastic ecosystem change on Christmas Island. The aim of this study was to investigate whether the restricted geographical distributions of D. celeste populations contribute to significant genetic structuring across Christmas Island, with an objective to inform future conservation strategies for this species on Christmas Island. Fragments of the mitochondrial cytochrome oxidase I gene and the control region were sequenced from 95 individuals collected from all five locations on Christmas Island known to be inhabited by D. celeste. Analyses using analysis of molecular variance revealed no evidence of population sub-structuring, indicating that despite any geographical isolation, there is a single population of D. celeste on Christmas Island. This lack of population differentiation is probably explained by the oceanic dispersal of larvae, rather than terrestrial migration of D. celeste. Therefore, based on these results, for conservation purposes, D. celeste on Christmas Island can be considered a single management unit.

The genus Turrisphaera Manton, Sutherland & Oates was described on the basis of material from West Greenland, Resolute Bay and South Alaska (Manton, Sutherland & Oates, 1976). In addition to these localities the genus has later been recorded from New Zealand (Moestrup, 1979) and Denmark (Thomsen, unpublished results). The diagnostic characteristics of the genus are the tower-shaped coccoliths and the small hexagonal crystallites. The two species described, the generic type T. borealis Manton, Sutherland & Oates and T. arctica Manton, Sutherland & Oates (Manton et al. 1976), were distinguished by the mucilage covering of T. arctica, and by a certain difference in the elaboration of the distal part of the coccoliths. Furthermore, in T. arctica the flagellar pole coccoliths were longer than the coccoliths elsewhere on the cell (all coccoliths appear equal in T. borealis), and the crystallites somewhat smaller than those of T. borealis.

A subtidal population of the anomuran crab, Pisidia longicornis was sampled quantitatively throughout 1997. Divers, using SCUBA equipment, conducted suction sampling each month, with concentrated effort directed towards the settlement season. Pisidia occurred in very high densities, constituting the major component of decapod community abundance. Gravid females were detected between March and September. Newly settled megalopae were present in benthic samples from June until late September. Six distinct settlement events were detected during this period, with pulses coinciding with low spring tides. Body size at settlement decreased as temperature during larval development increased. The rapid growth of each distinct settlement group was followed over time through each subsequent crab stage up to maximum adult size. Growth was suspended between December and April. Survival within each distinct settlement group was density-independent during the first summer's growth. Mortality increased between June and July settlement events, with the rate of decline remaining a linear function.

A field experiment investigating the effects of algal removal on benthic invertebrates and estuarine birds was carried out during September and October 2001. A randomized block experimental design was employed and three treatments were used: sites with algal cover maintained, when necessary by the addition of algae, sites with algal cover removed and control sites that were not manipulated in any way. Total invertebrate numbers increased during the experiment, but species varied in their response to the different treatments. Although Hydrobia ulvae showed the greatest increase in cleared sites after two months, there was no significant difference between treatments. Corophium volutator showed significant colonization of cleared sites during the experimental period, and numbers of Phyllodocemaculata also increased in the cleared sites. Results showed that while more sedentary benthic infauna are less capable of adjusting to the affects of algal clearance, more mobile epifauna and polychaetes show an ability to disperse to cleared sites in a relatively short period of time. Wading birds, however, did not enter the study site in any abundance during the experiment. Black-headed gulls (Larus ridibundus) were significantly more abundant in cleared sites than in algal cover-maintained or control sites when foraging.

The post-larval sand-eels (Ammodytidae) occurring in the Celtic Sea and Plymouth area are identifiable as Ammodytes lanceolatus, A. tobianus, A. marinus (not previously recorded from the area), and a fourth species of Ammodytes, the adult of which, it is concluded, is not yet known.

Adult Gymnammodytes semisquamatus (not previously recorded from the Plymouth area), the young of which are not yet known, increases the number of species in the area to five.

Shells inhabited by hermit crabs are unique microhabitats with an abundant epi- and endofauna. Using polychaetes as an example, communities associated with the whelk Stramonita haemastoma, the hermit crabs Clibanarius erythropus and Calcinus tubularis, as well as empty, damaged shells were investigated. No polychaete community was associated with live S. haemastoma: only 30% of the investigated gastropods harboured polychaetes. Hermit crab-occupied shells supported polychaete communities dominated by Spirorbidae in the case of Clibanarius erythropus and by small Sabellidae, Spirobranchus polytrema and Dipolydora armata in Calcinus tubularis. The polychaete fauna associated with empty shells was similar to that on shells previously inhabited by one of the hermit crab species but different from those of the surrounding hard bottom. The reproductive strategy of the some polychaetes species is adapted to life on this small-sized habitat.

During 1996–1997 a systematic sampling programme was carried out in brackish coastal lakes and lagoons and in the delta of the River Po. In six of the nine collecting locations, 12 species of Gastrotricha were identified. One species, Chaetonotus ichthydioides, is new to science; another three species, the chaetonotidans Heterolepidoderma foliatum and the macrodasyidans Dendrodasys ponticus and Turbanella cf. pontica, and one macrodasyidan genus, Paradasys (P. subterraneus), were found in Italy for the first time. The unusual morphology of some of the species identified shows that Gastrotricha colonized brackish waters from both marine and freshwater habitats.

The genus Megasyllis is herein reorganized excluding the size from the diagnosis, since it is not a characteristic of all the species of the genus. We provide here a taxonomic account of all known species and a key to species identification. Seven species are new combinations, and re-descriptions of the four latter are included: Megasyllis nipponica (Imajima, 1966) and M. multiannulata (Aguado, San Martín & Nishi, 2008) from Japan; Megasyllis procera (Hartman, 1965) from the Atlantic; Megasyllis pseudoheterosetosa (Böggemann & Westheide, 2004) from the Indian Ocean. Megasyllis glandulosa (Augener, 1913), from Australia; Megasyllis marquesensis (Monro, 1939) from the Marquesas Islands, Micronesia and Megasyllis subantennata (Hartmann-Schröder, 1984) from Australia. Four new species from the Pacific Ocean namely Megasyllis tigrina sp. nov., Megasyllis mariandreworum sp. nov. (both from Australia), Megasyllis chrissyae sp. nov. (from the Philippines) and Megasyllis eduardoi sp. nov. (from New Zealand) are described.