There is still often confusion as to the identity of species of compound ascidians. This is due sometimes to a lack of published observations on the group, and sometimes to seasonal variations from the described condition. An attempt has been made to follow the growth and variation of the species in the Plymouth area throughout the year. During the course of these investigations all the species of the sub-order Aplousobranchia formerly recorded from this area were encountered, with the one exception of Distaplia garstangi Berrill. In addition, two new species were taken: a species of Polycitor, the first record of the genus in these waters, and a species of Lissoclinum.

Many marine animals that live at depths greater than about 500 m are deeply coloured (generally red, brown, black or purple) even though there is little or no down-welling light in these regions (Clarke & Denton, 1962). The nature and function of many of these pigments are obscure. Partly, no doubt, because of the difficulty of provenance, there have been very few chemical and biochemical investigations on such pigments (see Crozier (1974) for a review of pigments in fishes). We report here an investigation of the pigments of meso- and bathypelagic medusae. The work was initiated following preliminary identification of protoporphyrin in Atolla wyvillei and Periphylla periphylla (Herring 1972): the present work confirms and considerably extends these observations (Head, 1976, M.Phil. Thesis, University of London).

The nematocysts of twenty species of Hydromedusae occurring at Plymouth are described. Of these, twelve were Anthomedusae and seven were Leptomedusae, and one was the Siphonophore, Muggiaea atlantica. The medusae fit very well into the generally accepted classification as regards the types of nematocysts they possess.

Lar sabellarum, the hydroid of Willia stellata, has a type of nematocyst not found in the other species—a macrobasic mastigophore. This is a further justification for the formation of a separate family, the Williidae, to hold this species and its relations.

While the Anthomedusae are clearly split up into distinct groups as regards their types of nematocysts, the Leptomedusae form a single group.

It is suggested that the so-called acrophores and anacrophores recorded in siphonophores may be merely stages in the development of other nematocysts.

It is urged that much more research is required on variation in size and structure of nematocysts in individual species before they can be used as specific characters for separating doubtful species.

The compound eye of the lobster H. vulgaris has a single lobe; its ommatidia are uniform except in length. Each ommatidium consists of a corneal facet, two corneagenous cells, four cone cells, a four-part crystalline cone, an elongate cone stalk, seven retinular cells and a four-part rhabdom. Growth between the zoaeal and adult stages is primarily a lengthening of the cone stalk.

The location and orientation of epizooic barnacles on the surface of their host is crucially important to the survival and growth of the animal and is determined at the time of settlement by the cyprid larva. The present study examines the location and orientation of Chelonibia patula barnacles on the upper surface of the carapace of the crab Portunus pelagicus from the Mediterrannean coast of Israel. Cirral activity behaviour patterns, such as turning angles of the cirral fan, types of cirral motion, and beat duration were determined with respect to the angular deviation of the rostro-carinal axis (RCA) of the barnacles from the direction of the incoming flow. While small barnacles (up to 1 cm rostro-carinal length) perform normal feeding beats and turn the cirral fan towards the incoming flow at all angles up to 180°, larger barnacles (>1 cm rostro-carinal length) do not extend their cirri when oriented at RCA angles exceeding 120°. Nearly all the sampled barnacles are oriented on the carapace at RCA angles of no more than 120° with respect to the anterior margin of the host crab, which is the predominant direction of incoming flow and food. It is concluded that larval choice of orientation at settlement is determined according to the direction of the current and the anticipated food-gathering ability of the adult barnacle.

New records are given of the occurrence of the warm-water barnacle Solidobalanus fallax in Britain and Europe. This barnacle is not found on rocks or stones, but settles on biological substrata, including algae, cnidarians, bivalves, gastropods and crustaceans. It also settles on plastic bags and nets, plastic-coated objects such as crab and lobster pots and octopus pots made of ceramic or plastic. With one exception the species was unrecorded in Europe before 1980; it may have increased in abundance during recent years as a result of rising temperatures. The cyprid larvae, which can metamorphose on plastic Petri dishes, appear to be adapted to seek out ‘low energy’ surfaces. One of the habitats colonized by S. fallax is the sea-fan Eunicella verrucosa, where it seems to have increased in recent years, possibly to the detriment of the cnidarian host. Solidobalanus fallax has the potential to be a serious pest of fish-farming structures to the south of Britain.

Three new species of the boring genus Aka, A. coralliirubri, A. microterebrans and A. ruetzleri are described respectively from the Mediterranean Sea, Celebes Sea and Caribbean Sea. The Indo-Pacific A. maldiviensis, known only for the structure of its epilithic fistules, is here described in more detail. The new species confirm that the sponges comprising the genus Aka are able to bore in biogenic substrata only, in particular coral rock, bivalve shells and the scleraxis of the precious coral Corallium. The study of the macroscopic excavation shows that three different patterns can be described: producing discrete boring chambers, large undivided cavities and interconnecting microtunnels giving rise to a spongious aspect of the substratum.

The intertidal phyllodocid polychaete Eulalia viridis (O. F. Müller) is widely regarded as a predator as stated, for example, by Newell (1970). This assertion is based on statements made by several authors, e.g. Moore & Kitching (1939), Glynne-Williams & Hobart (1952), Connell (1961), and Kensler (1964, 1967), who have reported E. viridis foraging over rocky substrates at low tide in daylight and in some cases have observed the insertion of the proboscis between the opercular plates of a barnacle and the subsequent ingestion of the soft tissues. The capture of a large chironomid by E. viridis has been recorded by Connell (1961). This was considered sufficient evidence for stating that E. viridis is a predator attacking living barnacles and other intertidal animals. Moore & Kitching (1939) further suggested that E. viridis might be as important a predator on barnacles as Thais lapillus (L). On the other hand Michel (1970) regarded E. viridis as a scavenger feeding on dead and decaying animals. There is evident disagreement about the feeding habits of E. viridis and consequently of its role in the population ecology of the community of which it forms a part. Examination of its feeding behaviour has been undertaken to clarify the situation.

The small intertidal New Zealand crab, Halicarcinus cookii undergoes a terminal pubertal moult, but this moult takes place over a wide range of pre-moult sizes. Relative growth of the abdomen width in immature females is positively allometric, but negatively allometric in mature females. Male abdomen growth is negatively allometric. Growth of the cheliped propodus in males is positively allometric, but in females it is negatively allometric or isometric. Overlap in the size-range of mature and pre-pubertal immature female H. cookii is 72% and in other hymenosomatids it can be as high as 87%. This overlap is probably the result of crabs having a variable number of pre-pubertal instars, but seasonal change in water temperature, with crabs moulting to a smaller final size during colder months and to a larger size during the warmer months is also possible. The net reproductive rate (Ro) of early and delayed moulters is compared and for H. cookii Ro e / Ro d = 1.0 so the size overlap is stable. Most hymenosomatids have determinate growth, but Hymenosoma orbiculare and Elamenopsis lineata continue to moult after maturity and have retained the ancestral link between moulting and mating.

The Indonesian archipelago is a ‘hotspot’ for invertebrate biodiversity (‘Coral Triangle’). In this area of ‘peak’ biodiversity, the origins of this high species diversity have often been debated. Xestospongia testudinaria is one of the sponge species that dominates coral reef sponge communities in this region. The role of the so-called ‘giant barrel sponge’ for the reef ecosystem has been studied repeatedly, as have its various bioactive compounds. However, the genetic variation of this iconic sponge in the region remains unknown. We investigate over 200 barrel sponge samples from Indonesia, and neighbouring as well as more distant localities (Saudi Arabia, Tanzania, Thailand, Taiwan, Java, Sulawesi and the Great Barrier Reef, Australia) using the mitochondrial cytochrome oxidase subunit 1. We compare our results with those from the studies on the congeneric barrel sponges Xestospongia muta from the Caribbean, and Xestospongia bergquistia from the Indo-Pacific, and observe a high degree of overlapping haplotypes between the three barrel sponge species, likely indicating the presence of ancestral polymorphisms. We discuss the implications of these findings to better interpret the phylogeography of barrel sponge taxa in the Indo-Pacific.

The construction of an artificial channel to a small embayment in the Chetumal Bay coastal lagoon complex, located on the Caribbean coast of Mexico, provided an opportunity to evaluate how large environmental changes influenced the structure of a low diversity benthic system. The objective of this study was to demonstrate that despite the absence of previous baseline information, the artificial channel has induced measurable changes in the biodiversity patterns of a hard substrata benthic community. The experimental design took into account the environmental setting influencing local benthic community structure and the sources of variability as a result of different substrate types and water depth. Four localities with ten replicates each were surveyed, and the presence/absence of macrobenthic biota species recorded during the rainy season. Our analysis using permutational multivariate analysis of variance indicated a significant increase in species richness in locations adjacent to the artificial channel. The highest species richness (66 species) was observed in the immediate area adjacent to the artificial channel and where exclusive species density was three to six times (18 exclusive species) than those present in other localities (6, 5 and 3 species) away from the channel. The presence of six species of hard corals indicated that the artificial channel offers a more suitable habitat for marine organisms colonizing the area than the natural channel. This study indicates the relative significance of confinement in structuring coastal lagoon benthic assemblages in tropical systems. Our results are similar to other findings underscoring the rate of colonization of marine organisms as a relevant process to explain benthic assemblage gradients and the importance of spatial–temporal interactions. The changes in species diversity caused by the artificial channel were clearly identified based on a sampling design that incorporated the main sources of environmental variability (distance to channels, substrate type and depth). Our study further demonstrates that changes in benthic community structure in the Chetumal Bay lagoon complex, as a result of human impacts, can be assessed even when community structure data before impact are absent.

Planktomya henseni Simroth 1896 is a pelagic bivalve widely distributed throughout the warm-temperate and tropical North and South Atlantic Ocean. It is also known from a single collection in the tropical Pacific Ocean. The geographical distribution of Planktomya is probably circumtropical.

Beach filling activities were conducted along the Mar del Plata coastline, Argentina, with sediments dredged from the harbour mouth between November 1998 and April 1999. We determined the percentage of imposex of Olivancillaria deshayesiana before, during and immediately after beach filling. The current situation (2005–2007) of imposex incidence was compared between populations from Mar del Plata and Mar Chiquita, a less impacted area. In addition, we evaluated differences in shell shape and body weight between females with and without imposex. The percentage of imposex was significantly higher during (85.3%) and after (73.9%) beach filling than before it (31.0%). No differences in body weight were found in the female population but shell length was significantly lower in females with imposex. As expected, the Mar Chiquita population showed no signs of imposex. This is the first report of imposex in beaches nourished with sand dredged from the port. Our results highlight the importance of analysing more carefully the sediment before beach filling. On the basis of the high level of imposex recorded near the port of Mar del Plata, O. deshayesiana can be used as a biological indicator of marine contamination with butyltin compounds.

Two berycomorph fishes, Hoplostethus atlanticus and H. mediterraneus, were captured by bottom trawls on the continental slopes to the west of the British Isles. H. atlanticus was seldom abundant and was distributed at a depth of about 1250 m both in the Rockall Trough and the Porcupine Sea Bight. H. mediterraneus was only present in the Porcupine Sea Bight and was moderately abundant at depths of about 750 m. Few juveniles of either species were captured and there was no evidence to suggest that H. atlanticus spawned in the area. Seasonal changes in the gonosomatic index of H. mediterraneus indicate that spawning occurs in the autumn and that the environmental conditions at this northern limit of its distribution may be unsuitable for larval or juvenile survival. Juvenile H. mediterraneus were relatively abundant in bottom trawls off West Africa. The diets of both species were broadly similar in that they preyed primarily on benthopelagic organisms, especially mysids, decapods, fish and cephalopods.

Thraustochytrids, the exclusively marine organisms of kingdom Stramenopila and a source of essential fatty acids in the marine milieu, possess an osmoheterotrophic mode of nutrition and are therefore affected by type and source of available organic matter and pollution. To study their response to heavy metal pollution, they were isolated from the brown alga Sargassum cinereum from the coastal waters of Dona Paula, Goa, India. A total of 22 isolates were obtained from two samples collected during February and March 2012. Based on their 18S rRNA gene sequencing, the majority of the isolates were identified as Thraustochytrium kinnei. The rest were identified to be Sicyoidochytrium minutum, Ulkenia visurgensis and species of Thraustochytrium and Aurantiochytrium. Six isolates were screened for various enzymatic activities. Characteristic and distinctive enzyme profile was obtained from isolates of different genera. All isolates were also screened for their tolerance to heavy metals. They showed good growth in the presence of Mn2+. The other metals that were tolerated by most of the isolates were in the order Ni2+ > Cr6+ > Zn2+. Seven isolates grew in the presence of Cu2+, and six in the presence of Cd2+. The isolates growing on metals showed vast differences from their normal morphology such as small colony size, shrunken cells etc. Scanning electron micrographs revealed holes or depressions in the cell wall in the presence of metals. On the whole, the isolates belonging to Ulkenia visurgensis and Aurantiochytrium sp. showed tolerance to more metals than Thraustochytrium kinnei. Cluster analysis showed no peculiar trend of metal tolerance to any particular genus as the characters were scattered in the clusters.

Nutrient enrichment is a significant cause of ecosystem change in coastal habitats worldwide. This study focuses on the change in a benthic macroinvertebrate community and environmental quality as assessed through different biotic indices following the construction of a sewage outfall pipe in the west of Scotland, from first implementation to seven years after operation of the pipe. Benthic macroinvertebrates are an important part of marine ecosystems because they mediate ecosystem processes and functions, are a key part of food webs and they provide many ecosystem services. Results indicated a clear change in benthic communities over time with an increase in species richness and changes to benthic community composition (specifically feeding type, bioturbation mode and ecological group) towards those indicative of organic enrichment. No clear spatial zonation was observed because organic carbon content increased over the entire area. According to a suite of benthic indices calculated, some negative changes were detectable following the start of sewage disposal, but largely negative community changes, and a change from ‘good’ to ‘moderate’ quality, only occurred seven years after implementation. The increase in species richness in response to increasing disturbance reduced the utility of a multi-metric index, the Infaunal Quality Index, which, instead of amplifying the signal of negative impact, dampened it. We suggest that any change in communities, regardless of direction, should be heeded, and species richness is a particularly sensitive and early warning indicator for this, but a suite of approaches is required to understand benthic community changes.

An assemblage of shallow-water fish was sampled with a small beach seine over monthly 24-h periods between April 2000 and March 2001 at the sandy beach Duće Glava in the eastern Adriatic. Monthly sets of samples were divided into day and night catches to examine the stability of diel differences in assemblage structure over a 1-y period. A total of 61 species was caught, of which six were exclusively diurnal and 12 were nocturnal. According to abundance and biomass of individuals during day and night, the most abundant species were categorized into several groups. Ophidion rochei was exclusively nocturnal, while Nerophis ophidion and Echiichthys vipera were mostly nocturnal. Diplodus annularis and Mullus surmuletus were slightly nocturnal. Diplodus vulgaris, Pomatoschistus marmoratus and Atherina boyeri lacked a diel pattern. Sardina pilchardus, Lithognathus mormyrus, Atherina hepsetus, Sarpa salpa and Mullus surmuletus abundance peaked for a few months, probably related to timing of spawning and recruitment. At the assemblage level, the diel per cent similarity index indicates that there were major differences between the day and night assemblages in April, September, March, and August with respect to number of individuals and September, October, May and March with respect to biomass.

The variability in motion behaviour properties was investigated for three species of intertidal gastropods at the inter-specific, inter-individual and individual levels in the absence of abiotic and biotic cues. Interspecific differences in movement patterns were reminiscent of the optimal searching behaviours expected for Austrocochlea porcata, Nerita atramentosa and Bembicium melanostomum in their natural environment. Specifically, N. atramentosa, A. porcata and B. melanostomum respectively displayed extensive and intensive foraging strategies consistent with their feeding ecology. The related inter-individual variability within each species highlights the potential ability of species to adapt their movement patterns to new environmental conditions and to persist over long-term changes. Finally, the strong variability observed in the speed and turning angle of individuals of the three species and the resulting behavioural plasticity may be an adaptive strategy to optimize energy expenditure and to react to an environmental fluctuation. Specifically, it is suggested that the lack of significant differences in individual behavioural variability between the three species indicates that despite clear inter-specific differences in motion behaviour, at the individual level A. porcata, N. atramentosa and B. melanostomum have similar abilities to face environmental fluctuations. This work stresses that individual variability in the motion behaviour of intertidal gastropods constitutes a fundamental evolutionary advantage when facing heterogeneous environmental conditions.

Portunus pelagicus (Crustacea: Portunidae) was collected monthly for a minimum of two years from two marine embayments (Cockburn Sound and Koombana Bay) and two estuaries (Peel-Harvey and Leschenault) that are located between 32° and 33°S on the lower west coast of Australia. A birth date of 1 December, derived from estimates of the peak time of spawning, was used to determine the average age of crabs in the main size cohort(s) in carapace width–frequency histograms for each month in each water body. The resultant carapace width-at-age data for each sex in Cockburn Sound and the Peel-Harvey Estuary, in which recruitment occurs at an early age, were then described using a seasonal von Bertalanffy growth curve. The results demonstrated that the growth rates of P. pelagicus differed significantly neither between females and males nor between crabs in the two water bodies and that growth was highly seasonal, with little or no increase in size occurring during the cold winter and early spring months. They also showed that relatively few P. pelagicus live beyond 18 months and indicate that, as a result of legal restrictions against retaining ovigerous crabs and the poor quality of recently-moulted females, fishing mortality is far lower amongst female than male crabs. The fact that the carapace widths attained by P. pelagicus at the end of its first year of life in Cockburn Sound (105 mm) and the Peel-Harvey Estuary (109 mm) were very similar to those in the Leschenault Estuary (105 mm) and Koombana Bay (107 mm) into which that estuary discharges emphasizes that the growth of P. pelagicus in each of these systems was similar. Data are also presented which strongly indicate that the second moult undergone by mature females is accompanied by an increase in the relative size of the abdominal flap.

The chromosomes of nine species of gammarids have been studied in oocytes and embryos. There is no evidence that polyploidy has played a part in gammarid evolution. Three of the species which we have studied, Gammarus pulex (L.), Marinogammarus marinus (Leach) and M. pirloti (Sexton & Spooner) show chromosomal polymorphism. There is no evidence that this polymorphism depends on the existence of a Robertsonian ‘fragmentationfusion’ system; rather it appears to be due to the presence of supernumerary chromosomes.