The present work describes the complete larval development of Mithraculus sculptus (two zoeal stages, the megalopa) and the first crab instar from laboratory cultured material. The larval morphology is compared with other descriptions currently available for the Mithrax–Mithraculus complex: Mithraculus coryphe, M. forceps, Mithrax hispidus, M. pleuracanthus, M. spinosissimus and M. verrucosus. Although the different species of the Mithrax–Mithraculus complex display uniform morphological characters, the first zoeal stage of M. sculptus differs from other species in the setal meristics of the carapace and the number of aesthetascs of the antennule. The second zoeal stage differs in the number of aesthetascs of the antennule and the number of setae in the distal margin of the coxal endite of the maxillule. The megalopa of M. sculptus can be distinguished by the presence of 3–4 aesthetascs and a simple seta in the distal segment of the antennule. The morphological differences between the larvae from the genus Mithrax and Mithraculus are insufficient to support the separation of the two genera using adult morphology. Future studies should address in detail setal meristics.

We studied the distribution of phytoplankton and ciliate communities in relation to environmental factors at 6 stations sampled between 28 and 31 July 2006 during the summer water stratification in the Gulf of Hammamet (Tunisia, eastern Mediterranean Sea). A strong thermocline was established at 30 m, and, on average, the N/P ratio was lower than the Redfield ratio (16), suggesting a potential N limitation. The inshore location was numerically dominated by dinoflagellates (55%) represented essentially by members of the genera Protoperidinium, Gymnodinium, and cryptic Scrippsiella trochoidea and on the offshore by diatoms (68%). The phytoplankton assemblage was largely dominated by the diatoms Thalassionema nitzshioides and Rhizosolenia styliformis, while the ciliate community was numerically dominated by small taxa such as Lohmanniella oviformis (6 × 102 cells l−1) and Uronema marinum (5.50 × 102 cells l−1). The total phytoplankton abundance increased from the coastal area (5.26 × 102 ± 4.48 × 102) to the open sea (10.33 ×102 ± 28.06 × 102) and decreased from the surface to the bottom, inversely to the ciliate abundance. Total phytoplankton and abundances showed similar patterns. Total ciliate biomass decreased from the inshore (0.25 ± 0.58) to the offshore (0.06 ± 0.10) areas but increased from the surface to the bottom. The diversity index of both phytoplankton and ciliate communities showed a decrease with a coastal–open sea gradient. The relationships between phytoplankton and ciliates suggest planktonic micro-heterotrophs were implicated in the channelling of matter and energy through the microbial loop in the Gulf of Hammamet.

The Tikehau atoll (Tuamoru Archipelago, French Polynesia) is located at 14°S 148°W. Phytoplankton and sand microalgae are the most important primary producers of the lagoon. They were studied for 4 years.

The relationship between light energy and lagoonal primary production was measured by using the 14C method for phytoplankton and O2 method for phytobenthos. Incubations, carried out in situ, were made at different depths and light exposition times.

Irradiance was high and 17% of the light energy measured at the surface reached 25 m (lagoon average depth). Maxima of phytoplankton and phytobenthos productions occurred at low depths; there was therefore no photoinhibition of photosynthesis. Correlations between light energy and primary production were strong, especially for phytobenthos. Multiplicative linear regression models (production vs light) associated with an exponential linear regression model (light vs depth), allowed planktonic and benthic primary production to be predicted from the depth and the light energy received at the surface. The benthic primary production exceeded the phytoplanktonic production in the upper 18 m. The total primary production (benthos + plankton) was constant with depth and depended only on light energy at the surface. One Einstein received at the lagoon surface allowed the growth production of 14 mg of carbon (water column + sediments).

Two new species of free-living marine nematodes, Daptonema longiapophysis sp. nov. and Cobbia sinica sp. nov. from the Yellow Sea, China are described and illustrated. Daptonema longiapophysis sp. nov. is characterized by spicules with a projection on the ventral and dorsal side respectively and the length of the gubernacular apophysis longer than the length of spicules. Cobbia sinica sp. nov. is characterized by one big dorsal tooth, long conico-cylindrical tail and gubernaculum with a small dorsal apophysis.

The description of the material used in the present investigation does not conform with that of Horstadius. Attention is drawn to this lack of agreement. A hypothesis based on viscosity changes within the egg has been advanced to explain the rounding off of eggs in sea water.

By means of what is called the transfer series the egg batch has been divided into a number of parts; the last liberated eggs being the ripest. The occurrence of large numbers of egg batches giving low maturity values has been attributed to maturity resulting from a series of changes whose rate after initiation gradually increases.

Attention is drawn to seasonal changes in the reactions of the germinal products. No definite lunar periodicity is shown in the ripening of the eggs.

The naked dinoflagellate Gymnodinium cf. nagasakiense is responsible for red tides frequently associated with mortality of marine organisms in North European waters during summer (see reviews by Tangen, 1977 and Partensky & Sournia, 1986). This species is currently referred to as Gyrodinium aureolum Hulburt in the literature, since its first occurrence in Norwegian waters in 1966 (Braarud & Heimdal, 1970). However, it was recently found to be morphologically closer to the Japanese bloom-forming species Gymnodinium nagasakiense Takayama & Adachi than to the original Gyrodinium aureolum (Partensky et al., 1988).

This paper is concerned with comparing the relative performance of small (0.1 m2) and large (0.25 m2) Hamon grabs for sampling the benthic macro-invertebrates from coarse offshore marine sediments. We present results based on an actual survey near the Isle of Wight, UK, but we also summarize and develop a statistical theory as well as demonstrate the theory using a small simulation study. Our results show that: the larger grabs are more difficult to handle, especially from small vessels; for a given sampling area the small grab can provide a more precise estimate of abundance than the larger grab if the individuals are clustered; the smaller grab can detect more species than the larger grab if individuals from the same species are clustered together (in our study, approximately 5% more species); and the smaller grab may undersample larger macrofaunal species and also species that live on larger cobbles.

We present theoretical equations to demonstrate the two samplers abilities to capture cobbles of different sizes. Multivariate techniques suggest that differences in the composition of the fauna collected using the different sized grabs are statistically significant, but small. It is more expensive to process samples from the smaller grab per unit area. However, per grab, the smaller grab is cheaper. We also present a model to demonstrate the effect on species occurrence and abundance.

Two new species belonging to Syngnatidae were newly recorded in the Gulf of Antalya, Turkish Mediterranean. These are reported for the first time from the Turkish Mediterranean (Anatolian coast) and for the second time the Mediterranean. These species are Hippocampus fuscus, immigrant from the Red Sea, and Syngnathus rostellatus, immigrant from the Atlantic Ocean.

In August, 1932, marked stratification of the water in the English Channel led to an unusual distribution of minor chemical constituents. Two thermoclines were present, between which high silicate values were found, indicating rapid re-solution of silica as found in former summers; pH was also very high at 15 metres.

In or about December in four years, nitrite in inshore waters has been found much in excess of that present in the open Channel.

The “mean cube Beaufort number” is suggested as a useful practical measure of sea disturbance. Three out of four midwinter plankton outbursts, inferred from a fall in the phosphate content of the water, have followed periods of sunny weather with little wind.

Two species of benthopelagic deep-water crustaceans, the suprabenthic mysid Boreomysis arctica and the bathypelagic euphausiid Nematoscelis megalops were analysed in their lipidic composition, with especial emphasis on fatty acids, from specimens obtained in the north-west of Mallorca (Balearic Islands, western Mediterranean) at depths ranging between 650 and 780 m. Temporal shifts were studied seasonally, based on five cruises performed in August and November 2003, and February, April and June 2004, using a Macer-GIROQ suprabenthic sledge (0.5 mm mesh size). Evidences of omnivorous and carnivorous feeding habits were found for both species derived from their fatty acid and other lipid profiles. Boreomysis arctica showed a more varied fatty acid profile than N. megalops. This suggests that B. arctica feeds on a wider range of food sources and is a more opportunistic feeder. The high proportions of 16:1(n-7), 20:5(n-3) and 22:6(n-3) fatty acids in both species suggests a link between surface primary production and deep slope habitats, while markers such as 18:1(n-9) and the 20:1(n-9) and 22:1(n-11) fatty alcohols indicate a predatory activity, likely on calanoids. These components may arrive both via phytodetritus deposition to the seabed and by migratory movements of prey consumed by B. arctica and N. megalops close to the sea bottom. Seasonal changes in the total lipids and fatty acid composition of both species are related to the seasonal dynamics in their food sources, coupled with changes in the physiological or developmental stage of individuals. The proportion of total lipids and polyunsaturated fatty acids in the two species may be related to the different life histories of B. arctica and N. megalops. The mysid has direct development of embryos within brood pouches, so eggs with large amount of vitelum are generated and gonad is well developed. By contrast, the meso-bathypelagic euphausiids generate planktotrophic larvae, with a high number of free developmental larvae stages (from nauplius to Furcilia/Calyptopis), and eggs with poor storage of lipid compounds compared with B. arctica embryos.

The intertidal crabs Neohelice granulata and Cyrtograpsus angulatus are common on the south-west Atlantic coast but they rarely share the same microhabitat. They are similar in size and in several life history traits which promote competition. Neohelice granulata is the dominant species in intertidal soft-sediment and salt-marsh areas from southern Brazil to northern Patagonia Argentina, where it forms extensive burrowing beds. Its burrowing activity affects sediment characteristics as well as the infaunal community. When both species coexist N. granulata constrains the distribution and modifies some population characteristics and burrowing behaviour of C. angulatus. However, C. angulatus live in burrows forming dense burrowing beds in soft-bottom intertidal areas where N. granulata is absent. Where both species coexist, C. angulatus rarely constructs burrows and N. granulata clearly dominate soft-sediment areas forming conspicuous burrowing beds. This suggests that these crab species could have similar ecological roles in some effects on sediments related to burrowing activities. In this study, we experimentally compare their effects on sediment characteristics and infaunal community. The results of the experiment showed that C. angulatus modify sediment water and organic matter contents and grain size–frequency distributions similarly to N. granulata. Neither N. granulata nor C. angulatus affected the mean abundance of infaunal organisms during the experiment but their variances showed the same patterns in many cases, indicating similar effects. These results indicate that C. angulatus can modify sediment characteristics similarly to N. granulata, and has similar interactions with infaunal species.

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.

The fishes harbouring parasites of the genus Lernaeocera can be divided, according to the presence or absence of contact with the coastal waters, into ‘inshore’ and ‘offshore’ groups. According to literature, only L. branchialis occurs commonly on hosts in both groups. The difference between this and the remaining species of the genus is explained by the existence of two different species covered by the name L. branchialis. One of these species is parasitic on cod and whiting, the other on haddock. The two species have also different intermediate hosts (flounder and lemon sole respectively) and differ in morphology of the adult male and female and in the mode of attachment to the final host.

Lernaeocera of whiting and cod is distributed mainly in the coastal area, while that from haddock extends over the whole of the North Sea. The former, but not the latter, is present outside the European continental shelf. All these differences lead to the conclusion that the two types represent two different species. The old name is retained for the parasite of cod and whiting. The parasite of haddock is the new species, to which the name Lernaeocera obtusa is given.

Previous studies of the anatomy of the oncomiracidia of the hexabothriids Rajonchocotyle emarginata and Hexabothrium appendiculatum have been made on unhatched larvae viewed through the egg shell or on larvae pushed out of the egg by coverslip pressure. A study of freshly hatched, free-swimming oncomiracidia has permitted a more detailed anatomical study especially of the gland cell system, the distribution of locomotory ciliated cells and surface sensilla and the flame cell system. Anatomically, the two larvae are closely similar but the oncomiracidium of R. emarginata possesses spherical refringent droplets in the locomotory ciliated cells and, in the head region, a pair of translucent bodies which may be photoreceptors. The oncomiracidia of both parasites possess posterior body gland cells with ducts entering the haptor. Such gland cells have not been recorded previously in the larvae of hexabothriids or in those of other polyopisthocotyleans and the function of these and other gland cells is discussed.

Levels of pollution, including contamination by toxic metals, in the Thames estuary reduced over the last four decades of the 20th century. This 2014 study investigates whether the declines in the bioavailabilities of trace metals (Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) have continued in the 21st century, using a suite of littoral biomonitors also employed in 2001 – the brown seaweed Fucus vesiculosus, the strandline, talitrid amphipod Orchestia gammarellus and the estuarine barnacle Amphibalanus improvisus. Bioaccumulated concentrations represent relative measures of the total bioavailabilities of each metal to the biomonitor over a previous time period, and can be compared over space and over time. Trace metal bioavailabilities varied along the estuary, and, in general, fell between 2001 and 2014, a reflection of the continuing remediation of the Thames estuary from its severely polluted state in the middle of the 20th century.

Cytotoxic activity of the mollusc Mytilus galloprovincialis haemolymph was considered as a possible marker of mussel health status. An easy-to-use and low-cost cytotoxicity test was set up to assess whether cytotoxicity is influenced by environmental stress such as an increase in water temperature or a reduction in water pH or salinity. Experiments demonstrated that, despite great variability in cytotoxic activity among the mussel populations, changes in the water physical conditions reduce mussel cytotoxicity, making animals more vulnerable to pathogen aggression.

Surveys conducted in the south-western Dominican Republic showed that the penshell Pinna carnea is a consistent component of seagrass beds and is absent in adjacent sandflats. Population densities were low (0.012–0.076·m−2) and the size–structure skewed towards large individuals. Trials with different types of substrata in caged spat collectors, involving a combination of sand, seagrass blades and roots, and an artificial treatment by itself, indicated no settlement preference for any of the substrata tested. Comparison of additional spat collectors (caged and uncaged) indicated high predation losses (84%) for recently settled penshells. Experiments with penshells measuring 10–30, 50–70 and 90–110 mm (anterior to posterior dorsal tip) transplanted to plots in a seagrass bed and sandflat showed that predation losses decreased with increasing size and were much less in seagrass than in the sandflat. In 10-day trials, survival in the three size-groups was 27-fold greater in the seagrass bed than on the sandflat. During 3-day trials in the sandflat, survival increased from 6% for 50–100 mm penshells to 93% for 150–170 mm penshells. At the end of 100-day trials, during which the study area was subjected to Hurricane Dennis, the only surviving penshells were large individuals (90–110 mm) that had been transplanted to the seagrass bed. All individuals transplanted to the sandflat went missing. Growth measurements showed that small penshells grow rapidly (up to 2.2 mm·d−1), but the growth rate drops markedly at ~150 mm. Rapid juvenile growth may be a strategy for reducing the period of high vulnerability to predators. The high proportion of large individuals in the population likely represents the accumulation of successive recruitments as growth slows in older penshells. Pinna carnea is mainly restricted to seagrass beds because they provide more protection from predators than adjacent habitats. Moreover, the consolidation of sediments in seagrass beds by roots and algal rhizoids provides a degree of protection from physical disturbances such as hurricanes. The advantages provided by the seagrass habitat come at a cost because we detected a mortality factor in the seagrass bed (possibly related to the ~3-fold higher silt load) that was absent on the sandflat.

The coast of Brazil is an important low latitude nursery ground for humpback whales (Megaptera novaeangliae). The number of humpback whales in this region has increased and its population is reoccupying areas where it has been depleted during the whaling period. The goal of this study was to conduct land-based observations during 2014 and 2015 to characterize patterns of habitat use and relative abundance of humpback whales that migrate to one of these reoccupation areas: Serra Grande, Bahia state. The observed mean group size was 2.12 ± 0.96 individuals and did not vary through the reproductive season nor between years. Dyads (32.9%) and singletons (26.7%) were more frequently observed, and groups with calves represented 21.2% of the sightings. The mean number of whales counted per hour increased from 2014 (3.44 ± 3.35) to 2015 (5.12 ± 4.18). Habitat use varied during the season; whales used shallower waters closer to shore as the season progressed. The spatial distribution of groups with calves was dependent on the presence and number of escorts. Spatial segregation of groups with calves closer to shore is a key factor in understanding the overall distribution of whales in the area, suggesting that social strategies are affected by environmental factors, as seen in other wintering grounds. Small-scale studies from land-based stations, in areas such as this where there is no previous knowledge about the species, are cost effective. They provide information about the overall behavioural and spatial patterns while anthropogenic activity is still low, allowing habitat protection and management decisions before implementation and increase of human activities.

Octocorals are common components of sublittoral benthic communities in temperate, tropical and polar areas. However, their natural diets and feeding rates are poorly known. The aim of this study was to determine qualitatively–quantitatively the diet of the octocoral Carijoa riisei (snowflake coral) and analyse the distribution and diet composition throughout a whole year at two different depths of the same environment. Hence, 30 colonies were haphazardly sampled for gastric content analysis from 2 and 6 m deep (surface and bottom) at Porto de Galinhas beach, Pernambuco, Brazil, in January, June and October 2006, and March 2007. Relative and absolute abundance, richness and occurrence frequency per gastric cavity were assessed. Shannon–Wiener index (H′) and evenness were also calculated. Items were classified according to the occurrence frequency. The biovolume of preys was estimated from meristic data, and from the biovolume were then estimated wet weight, dry weight and organic carbon. Weighed biovolume (WBV), which relates biomass and abundance, was assessed to estimate the real contribution of preys to octocoral diet. Results attested the presence of 102 phytoplankton and 25 zooplankton taxa. Mean prey size was 112.7 µm. Diatoms showed the greater richness with 88 morphotypes. Only cyanophytes and diatoms, from phytoplankton, were very common (>70%). As a whole, phytoplankton was also the most abundant group (83%), followed by crustacean fragments (5%). Thus, although having low biovolume (<0.09 mm3×10−3), the phytoplankton showed the highest WBV (44.5%). Feeding items richness was homogeneous throughout the study year and in both depths, while abundance showed significant seasonal and bathymetric fluctuation. The t-test (Hutchinson) found significant differences for prey item diversity related to depth and season. From the analysis, it is possible to conclude that the C. riisei population of the Brazilian north-eastern coast is polyphagous, but shows preference for phytoplanktonic elements and small prey. Therefore, the species behaves as a passive suspensivorous feeder with equitable biomass contribution from phytoplankton and zooplankton.

Intertidal organisms are particularly prone to the effects of both crude oil and to the chemicals commonly used to disperse the oil, following an oil spill at sea (Smith, 1968). A large body of literature now exists on the lethal effects of crude oil and dispersants but little progress has been made towards elucidating the toxic mode of action of these chemicals, nor to understanding what effects they exert when present in sub-lethal concentrations. Since the gills of aquatic animals are generally the most delicate of the epithelia exposed to the environment, it is likely that they will be most prone to damage by pollutants. Whilst previous workers using light microscopy (e.g. Clark, Finley & Gibson, 1974; Blanton & Robinson, 1973) have reported gross damage to the gills of mussels and fish following exposure to crude oil, there was no information available on the nature of the cellular damage at the ultrastructural level. In this study, we describe the nature of the lesions produced in the gills of the common intertidal limpet Patella vulgata following exposure to the water soluble fraction of North Sea crude oil and to the dispersants BP 1100 X and BP 1100 WD. A description of the ultrastructure of normal gill plates of Patella has been published previously (Nuwayhid, Davies & Elder, 1978).