The seasonal changes in the body weight and composition of two common boreo-arctic species of cirripedes, Balanus balanoides and B. balanus have been followed.

At a constant size (age under constant growth conditions) the body weight is closely related to the season. Increase in body weight takes place rapidly during the spring as reserves are laid down. These reserves are subsequently utilized for gonadal development.

The changes in B. balanus are more gradual than in B. balanoides and probably reflect differences in the habitat conditions.

The reserves, although contributing to the gonads, are not themselves adequate for their total tissue.

The interest in the temporal variability of the Northumberland benthos derives from a continuing time-series of samplings initiated in January 1971. Intensive sampling was started at a single station for the purpose of computing the secondary production for the years 1971–72 (Buchanan & Warwick, 1974). It became clear in the course of this exercise that there was a considerable degree of variation in species numbers and ranking, both between the two years and, seasonally, within single years. Sampling at this station was continued for a further two years - 1973–74 – and the data were interpreted as an un-broken rising trend in numbers of individuals with changes in species ranking and diversity (Buchanan, Kingston & Sheader, 1974). Since the magnitude of change over the four years was unexpectedly high, and largely unexplained, it was decided to continue the observations for an indefinite period and to expand the programme of sampling to cover several stations over a wider area of different sediment types.

The metabolic or respiratory rate, measured as the aerobic oxygen uptake, of the limpets Patella vulgata L. and P. aspera Lamarck was determined over a range of temperatures in January and in July. In order to determine the effects upon metabolism of adaptation to habitat, P. vulgata living at high shore levels were compared with those living at low shore levels.

The respiratory rate is proportional to the power –0·3042 of the fresh body weight and the relationship is not affected by temperature or season, and is the same for both species.

There is very little difference in the rates of respiration of equal weight individuals of P. aspera and either group of P. vulgata in January. In July the respiratory rate of low-level P. vulgata and of P. aspera is higher than in January whilst that of the high-level P. vulgata is little changed.

The Q10 of respiration had a low value between the temperatures of 15–20° C in both species, and this is thought to represent a hitherto unrecognized form of acclimation to maintain metabolic constancy over the mean environmental temperature range. In P. vulgata low values of Q10 were correlated with high environmental temperatures. Lower Q10's were recorded in July than in January and, in addition, limpets which were adapted to the elevated temperature of high shore levels in July had lower Q10's than the limpets from low shore levels. This apparent acclimation of Q10 was not observed in P. aspera.

The significance of the differences in metabolic rate and in Q10 are discussed in relation to acclimation and its importance in the ecological distribution of the two species.

Since the rate of global climate change began to accelerate in the 1980s, the coastal seas of Britain have warmed by up to 1°C. Locations close to the northern range edges of a southern trochid gastropod Osilinus lineatus in Britain previously surveyed in the 1950s and 1980s were resurveyed during 2002–2004 to determine whether changes in the success of near-limit populations had occurred during the period of climate warming. Between the 1980s and the 2000s, the range limits had extended by up to 55 km. Populations sampled over a latitudinal extent of 4 degrees from northern limits towards the centre of the range showed synchronous increases in abundance throughout the years sampled, suggesting a large-scale factor such as climate was driving the observed changes. These increases in abundance and changes in range limits are likely to have occurred via increased recruitment success in recent years.

The bivalves Thyasiraflexuosa and T. sarsi have enlarged gills which contain numerous prokaryotes. Gills from freshly collected animals contain high concentrations of elemental sulphur. Homogenates of gill tissue show activity for ribulosebisphosphate carboxylase, adenylylsulphate reductase, sulphate adenylyltransferase and sulphate adenylyltransferase (ADP), indicating that the prokaryotes are sulphur-oxidizing autotrophs. Both species can burrow to depths of 8 cm below the sediment surface and use their vermiform feet to construct channels penetrating deeper into the sediment. T.flexuosa and T. sarsi are scarce in sediments with high hydrogen sulphide concentrations and are not found in sediments where the sulphide zone is below their burrowing depth.

1. Fat occurs in all three types of cell composing the gastric epithelium at the end of a period of fasting extending over 6 or 7 days, but is completely absent from the mucosa of all post-pyloric regions of the alimentary tract at such a time.

2. There is a marked increase in the fat content of the superficial epithelium of the stomach after 30 hours and 50 hours of gastric digestion, the stomach being thus shown to be an effective organ of fat absorption.

3. Considerable quantities of fat are present in the duodenal and intestinal epithelia after fat-containing meals have been digested. The rectum is capable of some slight absorption, although its capacity in this respect is very much smaller than that of the duodenum or intestine.

4. It is suggested that there is a transference of the function of fat absorption from the stomach to the post-pyloric intestine when the frequency with which meals are taken is increased.

5. Globules of true fat are not typically observed in the areolar tissue layer of the alimentary tract, although lipoid granules may occur in abundance. It is suggested that resynthesis of the cleavage products of fats does not occur in this layer.

6. Data are presented bearing upon the rate of digestion of Mytilus edulis and Nereid worm.

The tellinid Macoma balthica moves extensively about the surface of the sand, its activities not being restricted to vertical movements as hitherto supposed.

These horizontal migrations comprise a movement towards the sun followed by a movement away from it. If there is heavy cloud movements still occur, in summer at least, but are at random.

Other intertidal species indulge in similar movements, possibly indicating a widespread habit which confers the advantage of bringing the animal into contact with surrounding areas while maintaining its station on the shore.

In September 2004, a rapid assessment survey for non-native species was conducted at 12 harbours along the south coast of England from East Sussex to Cornwall, focusing on communities of algae and invertebrates colonizing floating pontoons in marinas. Over 80 taxa each of algae and invertebrates were recorded, including 20 recognized non-native species. The southern hemisphere solitary ascidian Corella eumyota was recorded in the UK for the first time and was present at three sites. The colonial ascidian Botrylloides violaceus was also recorded as new to the UK, but was very widespread and has probably been present for a number of years but misidentified as the native congener B. leachi, which was infrequent. Other ascidians included Styela clava, introduced at Plymouth in the early 1950s, which was recorded at all locations visited, and Perophora japonica, which was found only at the Plymouth locality where it first occurred in the UK in 1999. The diverse algal flora included nine alien species previously recorded in the British Isles. Range extensions and population increases were noted for the kelp Undaria pinnatifida and the bryozoan Tricellaria inopinata, both first recorded in UK waters during the 1990s. The widespread occurrence of another non-native bryozoan, Bugula neritina, appears significant, since in earlier times this was known in UK waters predominantly from artificially heated docks. The results of this survey indicate that dock pontoon systems in southern England are significant reservoirs of non-native species dispersed by vessels and other means. The proliferation of these structures is therefore of conservation importance. The new UK records highlight the need for periodic monitoring of ports for non-native species.

Scientific data from the last 100 years are combined with primary and secondary historical information on the fisheries to summarize changes in the relative abundance of pilchards and herrings in the south-west in the last 400 years. The fluctuations in the two species are compared with recorded and inferred annual mean temperatures over the period. Pilchards are more abundant and extend farther to the east when the climate is warmer, as from 1590 to 1640 and from 1930 to 1960. In cooler times, as in the second half of the seventeenth century, herrings are more abundant while the pilchard fishery occurs later in the year and is restricted to west Cornwall. Lesser changes in the relative abundance of the two species and the timing of the fishery along the south coast of Devon and Cornwall in the intervening periods between these extremes accord fairly well with smaller fluctuations in climate. It is presumed that in addition to direct effects on reproduction and behaviour, changes in climate can indirectly influence the relative competitive advantage of the species through alterations in the associated ecosystem.

Patella vulgata were excluded from barnacle dominated areas at Port St Mary, Isle of Man by wire fences attached to the rock in September 1977, December 1977, April 1978 and July 1978. The sequences of algal colonization of these exclusion areas differed markedly with season: in autumn diatoms were followed directly by Fucus, in winter and spring diatoms were followed by green algae and then Fucus, and in late summer Fucus sporelings arose directly on the barnacles. There was no evidence that the initial stages were necessary for the subsequent recruitment of Fucus.

In the 4th to 8th thoracic segments of decapod Crustacea, at the bases of the peraeopods, sensory organs of various kinds have been found. They have been observed in Homarus vulgaris, Astacus astacus, Palinurus vulgaris, Eupagurusbemhardus, Carcinus maenas, Maia squinadoand described in greater detail for Homarus, Carcinus and Maia.

In all species examined there is in each peraeopod a proprioceptor consisting of a thin muscle with various nerve elements which extends from a point of the endophragmal skeleton situated near the ventral ganglia to the anteroventral part of the coxa. In the 4th to 7th thoracic segments of Homarus, in the 4th to 8th of Palinurus and Astacus, and in the 4th of the Brachyura, the receptor muscle is proximally attached to the tip of a chitinous projection of the endophragmal skeleton for which the term ‘receptor rod’ is proposed. In other instances it originates on the plate of the endosternite.

The nerve components of this ‘muscular receptor’ are of two sorts: (1) motor nerves spreading their branches over the whole length of the muscle, and (2) processes of the sensory neurons distributing their ramifications on the connective tissue associated with the muscle at its proximal end. The arrangement of the sensory elements is different in various species, but they all exhibit one feature, unusual in invertebrates, viz. their cell-bodies are situated within the central nervous system and not outside it.

Terms, dimensions and ratios for statolith description are defined. The form of the calcareousstatoliths in the Teuthoidea, Sepiodea and Octopoda is described by reference to Loligo forbesi, Sepia officinalis and Eledone cirrosa. While statoliths change in form and size during the growth of a cephalopod, the adult form is often characteristic for a species, despite some variation. Description of statoliths is important in studies of the fossil remains of cephalopods lacking calcareous shells, and will probably become important in the taxonomy of living species, in food analysis of cephalopod predators and in the study of deep sea deposits.

Nematode assemblages were sampled seasonally at three subtidal stations along the Belgian coast. The stations were characterized by muddy sediments (station 115), fine sand (station 702) and fine to coarse sand (station 790). The forces structuring vertical distribution were investigated by evaluating abundance, species composition, diversity and trophic composition, and relating these to sediment composition, redox state and food sources.

The nematode assemblages at the two finer grained stations (115, 702) were dominated by Daptonema tenuispiculum and Sabatieria punctata. For both species, the vertical distribution in the sediment seemed not dependent on the redoxchemistry, as former believed for S. punctata, but primarily influenced by food availability. This feature could also be recognized for Ixonema sordidum and Viscosia langrunensis, the most abundant nematodes at the coarse sandy station (790).

In general, nematode diversity was regulated primarily by sediment granulometry. Coarser sediments (station 790) yielded more diverse communities compared to the fine sediments (station 115, 702), however seasonal fluctuations and variations with depth into the sediment were not obvious. At the silty stations, when the sediment column was more oxidized in March, overall diversity was higher and showed a positive relationship to the mud content which varied with depth into the sediment. This positive relation is probably explained by an enhanced deposition of organic matter associated with the accumulation of fine particles near the river-mouths. Furthermore, the higher abundance, the lower diversity and the higher dominance found at the two silty stations of the eastern and the western part of the Belgian coast, pointed to a stressed, organically enriched environment.

The results demonstrate that controls on nematode community structure are complex and that information at both species and community level are required to properly evaluate the effects of natural and anthropogenic impacts.

The seven species of small copepod common in Loch Striven have been studied from vertical tow-net hauls taken there throughout the year 1933. These copepods were Pseudocalanus minutus, Paracalanus parvus, Microcalanus pygmaeus, Centropages hamatus, Temora longicornis, Acartia clausi and Oithona similis.

In general, the copepods began to reproduce about the time of the spring diatom increase in March or April, and produced a succession of broods throughout the summer; apart from the first these broods were not as a rule so clearly marked as in Calanus. Microcalanus begins to breed before the spring increase and has clearly marked broods like Calanus.

The mantles of the small squid Alloteuthis, the larger Loligo, and the cuttlefish Sepia contain an elaborate framework of connective tissue fibres running in different planes. Some of these fibres are apparently elastic. The circular muscle fibres which provide the power stroke in mantle contraction are of two types. Inner and outer mantle zones consist of well-vascularized mitochondria-rich fibres, whereas the central zone contains only mitochondria-poor fibres with a sparse vascular bed. Nerve terminals on the two fibre types are similar. The radial fibres opposing the circular fibres are of the same type as the central fibres, at least in the mid-region of the mantle. It is suggested that the central fibres are involved in escape jetting contractions, and that the fibres of the inner and outer zones are used during rhythmical respiratory contractions.

Mytilus edulis, Cerastoderma edule and Aequipecten opercularis were found to ingest zooplankton when suspended in mesh cages in the water column in the Firth of Clyde. Zooplankters were also found in the stomachs of bivalves that had been taken directly from their natural habitat. The bivalves consumed a wide range of zooplankton species, but selectively consumed smaller categories of zooplankton present. Condition of zooplankton in the stomachs of the bivalves varied with zooplankton species. A degree of larviphagy was evident, particularly in Mytilus edulis.

Goldman, McCarthy & Peavey (1979b) argued that growth rates of phyto-plankton in apparently oligotrophic ocean waters may near maximal. Their hypothesis was succinctly restated by Goldman (1980): ‘…the chemical composition of phytoplankton is extremely variable under exacting laboratory conditions of nutrient limitation and approaches the ‘Redfield’ proportions (C:N:P of 106:16:1) when neither nitrogen nor phosphorus is limiting so that near maximal growth rates are attained. In marine surface waters the chemical composition of particular matter often is in the Redfield proportions, thus implying that natural phytoplankton growth rates may be close to maximal.’ We argue on theoretical, experimental and observational grounds that this implication may not necessarily be correct.

A survey has been made of the biomass of the macrobenthos at twenty stations in the English Channel off Plymouth. The object was to provide a basis for following long-term fluctuations in the fauna.

A brief survey of physical conditions in the area is given, and a gradeanalysis of the soil at each station has been made.

Core-samples show that the sediment is shallow in many places and rock has been taken at 36 cm. or less below the surface at a number of stations.

Samples totalling ½m.2 were taken at each station with a modified 'scoopsampler', covering 1/10m.2, which is briefly described.

Sources of error in sampling are considered in detail. Some species may evade the sampler and others live too deep in the sediment to be taken. A comparison against a Petersen grab and a new ' suction-corer' show that the scoop-sampler does take a reasonably quantitative sample. The number of species taken in successive hauls, when plotted against the log of the area sampled, approaches a straight-line relationship similar to that obtained by Williams (1950).

A statistical analysis is made of a series of samples taken at one station, and the variance between the two samples in each haul and between successive hauls calculated. At this pàrticular station the fauna in successive samples is shown to be fairly random.

A sieve of 2-2 mm. mesh was employed. Compared with a finer sieve losses in terms of numbers may be quite large, but the total weight taken is little affected.

Aspects of the digestive cycle of Carcinus maenas have been studied by transmission and scanning electron microscopy, X-ray microanalysis and light microscopy. Movements of ingested material have been followed by feeding the crabs with Mytilus edulis (L.) labelled with colloidal particles of gold or thorium oxide.

Mesodinium rubrum is a marine planktonic holotrich ciliate of extremely wide geographical distribution which has often been found to be associated with ‘red water’ phenomena (Taylor, Blackbourn & Blackbourn, 1971). It has mainly been recorded from extremely neritic locations such as bays and fjords; away from the coast it is usually associated with regions of upwelling and in such conditions the blooms have been recorded as extending over areas as large as 100 square miles (Ryther, 1967). Fifty instances of the occurrence of M. rubrum are usefully summarized by Taylor et al. (1971).