The influence of various species of digenean trematodes on the in situ growth rate of Littorina littorea (Gastropoda: Prosobranchia) from different habitats was investigated. The main results showed: (1) that infections either reduced or had no significant effect on growth in comparison with uninfected snails; (2) that the same type of infection could have a differential effect on growth depending on the habitat/population from which the snails originated. These findings are consistent with the life history hypothesis expecting no or a stunting effect of trematode infections on the growth of longer-lived snails, but do also emphasize that growth rates following trematode invasion can be significantly modified by environmental conditions, such as, food availability.

Two sympatric species earlier differentiated by means of starch gel electrophoresis within Polydora cf. ciliata from the Sea of Japan are here identified and their adult and gamete morphology are described and illustrated. One species bores into various shells and coralline algae while the other bores only into gastropod shells occupied by hermit crabs. Both species have the prostomium anteriorly incised to rounded, 0–4 eyes, the caruncle extending to the end of chaetiger 2, heavy falcate spines of chaetiger 5 with a lateral tooth, branchiae beginning on chaetiger 7, and the pygidium disc-like to cup-shaped with a dorsal gap to only an incision. Males of the two species differ in aggregations of spermatids. The more opportunistic borer, which occurs in a greater number of hosts, always has 8-cell-aggregations of spermatids. These worms are here referred to as P. calcarea. The other species, in which spermatids are always interconnected in tetrads, is here described as a new one, P. manchenkoi sp. nov. The two species also differ in that prominent brownish-yellow pigment appears on the posterior segments after fixation in formaldehyde in P. manchenkoi sp. nov. but not in P. calcarea. It is suggested that spermatid aggregates and spermatozoan morphology be included in future polychaete descriptions when possible.

The growth in culture of Laminaria saccharina (L.) Lamour. and a species from Nova Scotia, tentatively identified as L. agardhii Kjellm., has been compared. Several characters, normally used for specific distinction within the genus Laminaria, have been shown to be modified by environmental conditions. These all concern the lamina and include the following: general morphology and texture, the shape of the base, the anatomical construction and the presence or absence of mucilage canals.

The question of the identity of L. agardhii from eastern and western Atlantic coasts is discussed.

The increasing occurrence of imposex in marine gastropods has been related to their exposure to the tri-substituted organotin compounds tributyltin (TBT) and triphenyltin (TPhT), which have been widely used as antifouling agents, and has been documented for more than 200 gastropod species. Odontocymbiola magellanica, a large benthic neogastropod, showed 85–100% imposex near harbours with high marine traffic in Patagonia. We evaluated if, as predicted by the energy allocation hypothesis, females with imposex (FWI) were on average larger and/or heavier than normal individuals, and if there were differences in shell morphometry associated with imposex, using both univariate and multivariate approaches. We detected differences in two morphometric variables, but no overall effect in shell shape, and ~10% of reduction in body weight in FWI. In addition, the multivariate index of size suggested a positive effect on FWI, in contrast to univariate analyses showing no differences in shell length. The present results demonstrate that responses to TBT vary among gastropod species and that the energy allocation hypothesis may be useful only under certain conditions.

Sea water from the Plymouth district and sea water from the Firth of Clyde each produced, from the same batches of fertilized eggs of Echinus esculentus, a different morphological type of larva. Each type was clearly recognizable irrespective of the copper concentration up to a level higher than that ever likely to be found naturally in the localities from which sea waters contrasted in earlier experiments had been obtained. Suggestions by continental workers that these earlier results may have been due to varying copper concentration are thus shown to be inapplicable.

The accumulation of 134Cs and 42K from artificial sea water has been followed in crabs of the following species, viz. Carcinus maenas, Portunus puber, P. depurator, Polybius henslowi, Cancer pagurus and Corystes. cassivelaunm. In all cases 134Cs is taken up far more slowly than 42K but at equilibrium a higher concentration factor is attained by 134Cs. In Carcinus a value of about 8 is found for 134Cs and about 4 for 42K. Uptake of 134Cs in Carcinus is not affected by feeding on inactive food over a period of 1000 h. The relationship between the rates of uptake of the two isotopes is not the same in the different species and it is concluded that it would not be possible to predict with any accuracy rates of uptake for 134Cs in other species of crabs from the results of short 42K experiments.

Uptake of 134Cs was followed in the blood and tissues of Carcinus and Cancer, and muscle is the principal limiting factor in the attainment of equilibrium by whole animals. Uptake of 42K by tissues has also been followed and in all species nearly all the inactive K appears to be readily exchangeable. At equilibrium in all species plasma/sea water and tissue/plasma 134Cs ratios nearly always exceed those for inactive K. The tissue/plasma 134Cs ratios in Carcinus are about twice those for K and the significance of this has been discussed.

Loss of both isotopes in whole Carcinus is a slower process than uptake.Isotope accumulation takes place mainly across the body surface in unfed animals, but uptake of 134Cs from food is very rapid and complete and would considerably enhance the attainment of equilibrium in a natural environment.

Selective excretion of 134Cs relative to K has been found in Carcinus, Cancer and Portunus puber.

The ecology of the sepiolid Sepiola atlantica in Firemore Bay, Loch Ewe, on the west coast of Scotland was investigated by beam trawling surveys. Low densities of this species were present in the shallow sublittoral zone of the sandy bay. A size range of 4–21 mm dorsal mantle length (DML) was obtained, with no significant differences detected between the mean sizes of males and females. Males reached gonadal maturity slightly earlier and at a slightly smaller size than females. Sepiola atlantica was present in the bay in each of the months in which sampling took place suggesting a resident population, the structure of which varied considerably. Juveniles were found over a prolonged period of the year but peak recruitment (animals of 4–10 mm DML) was in May and July. Animals <4 mm DML were not caught and no egg masses were found in the trawls. In aquarium conditions, S. atlantica fed on live crustaceans such as mysids, Crangon crangon and Palaemon serratus, although Corophium volutator, an estuarine crustacean not normally found in the marine sandy bay, was the most accepted food.

The trophic interactions between primary consumers and the organic matter sources in a man-made intertidal ecosystem were investigated. The most representative invertebrates that occupied the different habitat types tend to use similar food sources, namely benthic diatoms and suspended particulate or sedimentary organic matter, although they do so in different proportions. Fucus vesiculosus was abundant on the rocky substrate but this macroalga nor its epiphytes contributed importantly to the diet of the primary consumers inhabiting these assemblages. In contrast, benthic diatoms from the nearby mudflat were directly used as a food source because of their re-suspension in the water and transport by the tide to the artificial rocky shore. The results suggested that the trophic pathways in this intertidal environment were relatively simple.

Numerous studies have focused on the soft bottom macrozoobenthos from Mediterranean transitional environments, pointing out a correlation between the variation in environmental parameters and changes occurring in benthic communities. Less attention has been paid to the study of hard bottom organisms settling on both natural and artificial substrates usually present within the basins and often constituting peculiar communities. The ecological role of such communities is remarkable, since they often reach high values of species richness and include bioconstructor organisms able to build true reefs. These reefs can strongly impact the environment, improving biodiversity through the increase of spatial heterogeneity. The present work aims to supplement new faunistic data on five lagoon systems of the south-eastern Italian coast, integrating the still fragmentary knowledge of their macrozoobenthos through the study of hard substrate communities. Sampling was performed on hard substrates colonized by complex benthic communities. The assemblages recorded were then compared in the light of the study sites’ main ecological traits. Our data highlighted the occurrence of a rich benthic macrofauna, with 100 taxa found. This markedly increases the value of species richness reported in the literature for the macrozoobenthos of the study sites. In particular, the species list provided for the Ugento Basins was the first ever compiled for this site. In spite of their geographical proximity, the investigated sites, according to their diverse environmental conditions, showed substantial differences as regards their respective macrozoobenthic communities.

This study tested for social monogamy in Alpheus brasileiro Anker, 2012. We also analysed egg production in this species. Sampling was conducted bimonthly from March 2013 to January 2014, and specimens were collected manually in the intertidal estuarine zone of Cananéia, São Paulo, Brazil. A total of 186 specimens (92 males and 94 females) were captured, and ~46% of them were found living in heterosexual pairs. The carapace length (CL mm) of paired males and females was positively correlated. We analysed 35 females carrying eggs underneath the abdomen: 28 of these females had eggs in stage I of development, four had eggs in stage II, and three had eggs in stage III. The average (±SD) mean fecundity for females carrying early (stage I) eggs was 149 (±93) eggs. Egg volume differed significantly among developmental stages, with a 35.4% increase in egg volume between stages I and III. The egg volume and size (CL) of females correlated positively. A positive correlation between the number of eggs and carapace length was found, with a proportional increase in the number of eggs according to the size of females. Our results suggest that the studied population of A. brasileiro is socially monogamous and provide the first insights into egg production in this species.

The common sandhopper of European shores, Talitrus saltator (Montagu, 1808) (Crustacea: Amphipoda) remains inactive in high shore burrows for much of the winter in more northern latitudes. In the laboratory exposure to low temperature (2 or 3°C) was accompanied by the onset of inactivity, a precipitous decrease in oxygen uptake and a marked increase in the concentrations of the major ions in the haemolymph. The increase in the concentration of Mg2+ in the haemolymph was particularly pronounced. The possibility that Mg2+ ions are implicated in bringing about a reduction in activity and oxygen uptake is discussed.

The objective of this study was to analyse the differences in shape of the cephalothorax in four fishery stocks of sea-bob shrimp Xiphopenaeus kroyeri that are distributed on the east coast of Brazil, applying geometric morphometry as the analytical tool. Samples were collected at the fishing ports of Caravelas (17°43′S 39°15′W), Vitória (20°15′S 40°14′W), Atafona (21°35′S 41°01′W) and Farol de São Tomé (22°02′S 41°02′W), and variations in shape of the cephalothorax of the shrimps were evaluated by univariate and multivariate techniques. Analysis of variance followed by the Tukey test indicated that shrimps collected at the port of Farol de São Tomé were significantly smaller than the others, and size of individuals was inversely related to latitude. Discriminant analysis revealed the formation of two morphologically different groups between the areas of collection. Individuals collected in Caravelas, Vitória and Atafona, suffering permanent influence of freshwater discharge, associated with sandy–muddy substrate, constituted a different group compared to individuals collected in Farol de São Tomé, area without this kind of influence and with sandy substrate, where the average water temperature is lower and salinity is higher. Considering the commercial importance of the target species, the technique could be applied to its fisheries management. It allows the recognition of stocks and inference about the processes of fishing area occupation.

This study monitors the spatial and temporal variability of sea ambient noise (SAN) in the Cres-Lošinj archipelago from 2007 to 2009 (north-eastern Adriatic Sea, Croatia). The archipelago is an important marine habitat for many protected species, including the bottlenose dolphin (Tursiops truncatus) that is considered as vulnerable to disturbance from intense local vessel traffic. Systematic monthly sampling of SAN was carried out at ten predefined acoustic stations. Data on the presence, type and distance of vessels from these stations was also collected during sampling and vessels were allocated into four main classes. A sample of noise produced by a representative vessel of each vessel class was collected and the noise levels were extracted on the 1/3 octave band standard centre frequencies. All the recordings were analysed in terms of instantaneous sound pressure level (LLSP, L-weighted, 63 Hz–20 kHz, root mean square fast). The equivalent continuous sound pressure levels (LLeq) for vessel and SAN were calculated averaging the LLSP of vessel and SAN samples. Results indicate an increase of SAN levels particularly in the range of low frequencies (63 Hz–1 kHz) during the tourist season. A positive relationship was found between the spatial and temporal distribution of SAN and seasonal changes in anthropogenic pressure, in terms of vessel traffic. Potential implications for local marine life, with particular reference to bottlenose dolphins, are discussed.

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.

Heterosaccus lunatus parasitizes the portunid crab, Charybdis callianassa, in Moreton Bay, Queensland, Australia. Larval broods, released during July and August (males only), were allowed to develop through to cyprids (lecithotrophic development). Speeds of all the developmental stages—nauplius I to nauplius IV and the cyprids were measured by timing continuously swimming larvae over 5 mm distances under a microscope. The absolute speeds of the naupliar stages were similar (3–4 mm s−1), but the cyprids were significantly faster at ≈10 mm s−1. These speeds were compared with published speeds of cirripede and copepod nauplii and other cirripede cyprids. Relative speeds (body lengths s−1) showed surprising parity, which for the cyprids probably reflects the similar efficiency of the fusiform shape and thoracopod propulsion for all sizes of this highly specialized larval form. The lecithotrophic H. lunatus nauplii have rather minimalistic appendages (compared with planktotrophic nauplii) which were examined at the light microscope and scanning electron microscope levels. The natatory setae were found to be plumo-denticulate.

As modern instrumentation improves the precision of the measurements of underwater light, particularly of monochromatic light, both biological and physical oceanographers are becoming increasingly interested in such measurements in deep water

A number of naturalists have expressed their belief that the movements of the adult herring (Clupea harengus L.) at certain seasons are governed by the relative abundance or scarcity of their food or other organisms in the plankton.

The structure and ciliation of the lip-apparatus of two species of Lima—L. hians (Gmelin) and L. excavata (Fab.)—and one species of Pecten—P. maximus (L.)—is described.

It is suggested that the lips of these three species of bivalves have been hypertrophied (and in one case partially fused) in order to retain particulate material being carried from the ctenidia to the mouth while at the same time allowing the escape of water currents, generated by the ciliary tracts of the ctenidia and palps, from the proximal oral grooves. Such water currents must emerge from between the lips of all bivalves but do not usually interfere with the passage of particulate material. In the Limidae and Pectinidae, these water currents have been intensified by the reduction of the anterior regions of the mantle cavity. Since this change in the proportions of the body can be correlated with the evolution of the monomyarian condition in the Anisomyaria, it is postulated that the lips of all monomyarian Anisomyaria will be similarly hypertrophied.

Experimental removals of the dominant canopy-forming kelp Ecklonia radiata were conducted at two sites on rocky walls in New Zealand and monitored for approximately 1.5 years. We hypothesized that the removal of the E. radiata canopy would affect the structure of subcanopy assemblages, such that there would be a reduction in sponge species richness and abundance. Furthermore, we investigated the biological and physical (predictor) variables that best explained variability in sponge assemblages after canopy removal. Canopy removal led to a community dominated by turf algae, which corresponded with a decrease in sponge abundance and richness. Our results suggest that the Ecklonia canopy may positively influence the presence of sponge species such as Crella incrustans; we propose that the canopy may allow its coexistence with turf algae underneath the canopy by altering the light regime and other environmental factors, which may be detrimental for some species. Our results highlight how any loss of canopy-forming species might have negative effects on sponge assemblages, which could affect the energy flow and the overall biodiversity found in these habitats.

Identification of the range boundaries and microgeographic distribution of cryptic species is greatly facilitated by the use of genetic markers. Here we characterize the geographic range overlap between two cryptic species, Chthamalus fissus and C. dalli, and show that as with other barnacle species, their distribution and abundance is probably dictated more by microhabitat characteristics and the presence of conspecifics than broader environmental gradients. We also show that C. dalli appears to be panmictic across the studied range.