The distributions of the pennatulid anthozoans (sea pens) Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis in Scottish waters have previously only been extensively documented in sea lochs, by the Marine Nature Conservation Review (MNCR) surveys. Funiculina quadrangularis in particular was thought to be restricted to the deep basins of sea lochs and is classified as a nationally uncommon species. Sea pens are characterizing species in seven biotopes found in Scottish waters and are protected under the ‘Mud in Deep Water Habitat Action Plan’ of the UK Biodiversity Action Plan (UKBAP) and are also recorded in several Special Areas of Conservation. The present study has extended the existing information available on sea pens in Scottish waters. The distribution and abundance of the three sea pen species were mapped using GIS (Geographical Information System) by utilizing data from Nephrops norvegicus stock assessment video surveys carried out by Fisheries Research Services (FRS) Marine Laboratory. Distribution was shown to be aggregated for all species. Funiculina quadrangularis was present in areas outside the sea lochs, such as the South Minch and the outer mouths of most sea lochs. This study demonstrates that analysis of video footage derived from Nephrops stock assessment surveys can significantly extend our knowledge of sea pen distribution and population density. Future management of Nephrops stocks can be expected to consider impacts of fishing on non-commercial species such as sea pens as a part of the ‘ecosystem approach’ to management.

In aquatic food webs zooplankton constitutes an important link between primary producers and higher trophic levels. Copepods often dominate the zooplankton in coastal oceans and are the prey of the majority of planktivorous fish. Feeding behaviour, as well as the food quantity and quality are recognized factors that affect copepod growth, and therefore, the energy transfer efficiency throughout food webs. The natural occurrence and magnitude of these growth factors and their combined effects on marine copepods, as keystone grazers in the pelagic marine realm, are poorly understood. Here, we assessed how these different factors vary throughout the year, and then examine their relative influence upon copepods maximal growth rates. A multiple regression model, including all variables previously selected, and the inclusion of the sea temperature allowed us to estimate the pure influence of the studied factors, and the environmental effect on copepod growth rates. The results imply that ingestion of diatoms may induce a positive effect on specific growth rates of copepods, and the quality of this food item (high PUFA and HUFA availability) might explain such effect. Therefore, seasonal variability in diatom abundance, possibly driven by changes in the oceanographic regime, should be considered a critical factor controlling copepod growth in productive coastal ecosystems.

The present study reports the occurrence of two exotic species of polychaetes in Izmir Bay, the eastern Mediterranean: Streblospio gynobranchiata, newly reported for the Mediterranean, and Polydora cornuta. Their establishment in the area is most probably transport by ballast water since these two species greatly dominated polluted muddy bottoms near and in Alsancak Harbour. The maximum density and biomass of S. gynobranchiata in the area were 34,270 ind m−2 and 9·4 g wwt m−2, and those of P. cornuta were 3170 ind m−2 and 2·1 g wwt m−2, respectively. These two species accounted for more than 60% of total faunal populations in the majority of samples collected in winter. Both species are capable of reproducing in the area both in summer and winter. The morphological, ecological and distributional characteristics of these species as well as their impacts on the prevailing ecosystem are analysed and discussed.

Recent molecular studies have proved beneficial in providing taxonomic resolution within the Octopus vulgaris species complex, therefore aiding in the appropriate management of this high value global fisheries resource. This study used the mitochondrial ‘barcode of life’ gene Cytochrome Oxidase subunit I (COI) to investigate the identity of shallow-water benthic octopuses in the mid-Atlantic Ocean and their relationship to members of the Octopus vulgaris species complex. Maximum likelihood and Bayesian phylogenetic inference placed individuals collected from two tropical islands, Ascension and St Helena, into a highly supported monophyletic clade with the North Brazilian species O. insularis (BS = 81, PP = 1), extending the known distribution of O. insularis to Ascension and St Helena Islands. Octopus vulgaris and two other member species of the O. vulgaris species complex, O. tetricus and O. cf. tetricus formed a highly supported monophyletic clade (BS = 99, PP = 1). Interspecific distances between the O. mimus group (O. mimus, O. bimaculoides, O. maya and O. insularis) and the O. vulgaris species group (O. vulgaris, O. tetricus and O. cf. tetricus) ranged from 14.7–26.0%, and an estimated date of divergence suggests these groups diverged from a common ancestor between 19.0 and 40.9 million years ago.

As known from ancient times, Electric Rays (Torpedo) have the power of giving severe numbing shocks, and it has repeatedly been stated that this power, which is electrical, is used both as a means of protection and for paralysing prey. That the shock is used in the capture of prey seems never to have been definitely proved. Indeed Roule (1935, p. 161) expresses the opinion that the electric shock is not used for securing food and even doubts that it is normally and effectively used as a means of defence. There appears to be no detailed account of the manner in which Torpedo feeds, but the ninth edition (1925) of the Guide to the Aquarium of the Zoological Station at Naples mentions (p. 106) that the Electric Ray rises from the mud to throw itself against approaching mullet (Mugil), and that the mullet, overcome by fright and electric shock, fall to the ground to be eaten. This very short and incomplete account was not seen until after the following paragraphs had been written.

Both Torpedo nobiliana Bonaparte and T. torpedo L. occur from time to time off Plymouth, the former being by far the commoner, and both have been kept in our aquarium tanks. They are sluggish fishes, spending most of the time lying still on the bottom, occasionally swimming for short spells. They swim by sculling with the tail, which has a large caudal and two dorsal fins. This mode of swimming differs strikingly from that of normal rays, which undulate the pectoral fins and trail their tails' it resembles the swimming movements of Rhina squatina (L.), another fish with a sluggish disposition and, as noted below, some other resemblances to Torpedo.

Surprisingly little is known about the influence of salinity on embryo development in crustaceans despite its obvious potential importance to species which breed in inshore estuarine waters. Evidence from the literature is that embryo salinity tolerance may differ from that of later stages in the life history (e.g. Kelley & Burbanck, 1976; Rosenberg & Costlow, 1979; Hartnoll & Paul, 1982; Jones & Simons, 1982; Wear et al., 1986) and such differences may impose restrictions on distribution. Wittmann (1984) referring to mysids, emphasised that an understanding of incubation period and factors influencing it "appears to be a key factor for the understanding of variations in the length and timing of the breeding season, age of maturity, frequency of broods, numbers of young per brood, egg size, and adult body size".

The Marine Nature Reserve of Lough Hyne (south-west Ireland) encompasses an extremely wide range of marine conditions within a small area. A total of 378 boulders were collected from a range of depths at five sites subjected to very different degrees of water movement and sedimentation. Encrusting biota were identified and the communities compared between sites and upper and lower surfaces. In all, 114 taxa were identified. Alpha diversity was generally found to be higher for lower surfaces at sites with intermediate flow/disturbance. Sites with high water flow had much greater space occupation, predominantly cheilostomatid bryozoans. Multivariate analyses divided the samples into six groupings. Similarity percentage analysis (SIMPER) was used to indicate particular species characteristic of each group. Equations for the species-area curves generated tended to indicate communities at equilibrium except at sites subjected to stresses such as high sediment load or high disturbance. For high disturbance sites it was apparent that number of species cm−2 was significantly negatively correlated with surface area of rock implying non-random distribution.

Worms for dissection, or for museum preservation, should be prepared by the magnesium-formalin method, of which two modifications are given in the text.

The body of Arenicola is differentiated into: (a) an achaetous ‘head’, comprising the prostomium and a small number (probably two) of subsequent segments, (b) a ‘trunk’, composed of a number, varying somewhat with the species, of chaetigerous segments, and (c) a ‘tail’, which may or may not be chaetigerous according to the species. The method of subdividing the body according to the distribution of the gills, so often met with in the literature, is misleading because it conceals the very fundamental differentiation between ‘head’ and ‘trunk’.

The main layers of the body wall are described. There are grounds for supposing that the circular muscle layer plays a greater part than the longitudinal in the maintenance of a postural fluid pressure in active worms.

One hundred and twenty-one specimens of Calanus finmarchicus were anæsthetised in a dilute solution of Urethane (2·5 grms. in 100 c.c. of seawater) and the time taken by each to sink through a measured distance determined. The length of each specimen, in millimetres, was noted, and the relationship between sinking time and length of the individual was determined. The coefficient of correlation, r, was found to be —0·63.

Apstein (1910, p. 23), working with preserved material, found that the time taken by adult Calanus was less than that taken by young. He does not give actual length measurements. Eyden (1923, p. 53) showed that for anaesthetised specimens of Daphnia pulex, the average rate of fall was approximately twice as great in specimens of length 2·5–3·0 mm. as in smaller ones, whose length varied from 1·5–2·0 mm.

The position in which specimens sank was conditioned by the manner in which the antennæ were held. It was found, however, that this had not as great an influence on the sinking rate as might have been expected.

Of the 121 specimens examined, 21 were in Stage IV, 41 in Stage V; 59 were adult, of which 54 were females and only 5 were males.

Surveys of marine benthic distributions are usually performed by sampling from a vessel capable of handling the heavy sampling devices necessary. Because of the inability of such vessels to work in very shallow water or close to the shore the area just beyond the intertidal zone is inaccessible to investigation except by a special vessel (e.g. Mclntyre & Eleftheriou, 1968) or by using diving techniques (e.g. Hughes & Thomas, 1971). This has created a gap in our knowledge of this area, which may be of some importance in reflecting adaptation to effects of land on sea which are not complicated by the effects of tidal exposure.

It has been suggested (McLusky, 1968 a) that migrations of Corophium volutator (Pallas) may occur in response to salinity. This suggestion was based on distributional evidence from the estuary of the River Ythan, Aberdeenshire, and assumed that the animals are able to detect salinity and exhibit a behavioural response to it. The presence and nature of such a response has been investigated by means of choice experiments. Burrowing, swimming and feeding behaviour of C. volutator have been studied by Meadows & Reid (1966) and Morgan (1965).

The distribution, morphology and sensory cell polarity of neuromasts were followed in developing larvae and recently settled juveniles of Dover sole (Solea soled) and plaice (Pleuronectes platessa) using scanning electron microscopy. In plaice the number of neuromasts increased at a similar rate on both sides of the fish throughout development, and most head neuromasts became incorporated into canals. On the trunk presumptive canal neuromasts were outnumbered by accessory superficial neuromasts in early juveniles. In sole the number of neuromasts increased at a similar rate on both sides until the start of metamorphosis. Subsequently a proliferation of superficial neuromasts on the abocular side of the head resulted in 80% of all the neuromasts on this side of the fish being located on the head in early juveniles. Both species had developed asymmetry of the head canals by the early juvenile stage, while canal formation on the trunk commenced later on the abocular side than on the ocular side. Mean numbers of sensory hair cells per neuromast showed little change until metamorphosis in both species, after which there was a two- to three-fold increase in hair cell number. The polarities of the sensory hair cells showed more variability on the head than on the trunk in both species. In general, hair cells were aligned for maximum sensitivity along the axes of the canals which would subsequently enclose them, but in the case of the superficial neuromasts on the abocular side of the head in sole the polarities followed surface features such as the nares, papillae and fin rays.

A new free-living marine nematode species, Oncholaimus moanae sp. nov., is described from intertidal fine sand in southern New Zealand. Oncholaimus moanae sp. nov. can be distinguished from other species of the genus by the presence of a pre-cloacal papilla bearing four pairs of short, stout spines, a post-cloacal papilla, long (>70 μm) spicules, and a demanian system with two openings situated laterally at level of uvette. The δ13C signature of O. moanae sp. nov. suggests that benthic microalgae are the main carbon source for this species, but an elevated δ15N signature suggests predatory feeding habits. The fatty acid composition of O. moanae sp. nov. is rich in highly unsaturated fatty acids, which are likely to originate from heterotrophic protists (e.g. ciliates). The data obtained in this study suggest, for the first time, that marine nematodes can be a high quality food source (i.e. rich in highly unsaturated fatty acids) to predators. Large nematodes living near or at the sediment surface, in particular, may represent an important trophic link between heterotrophic protists and higher trophic levels in marine sediments.

Ecological, behavioural and anatomical observations of a commensal bivalve, Peregrinamor ohshimai (Mollusca: Galeommatoidea), were carried out in a tidal mudflat in the Seto Inland Sea, Japan. The bivalve attached specifically to the longitudinal groove of the ventral side of the cephalothorax of thalassinidean burrowing shrimps, Upogebia major and Lf. narutensis (Crustacea: Decapoda), singly, dorso-ventrally and longitudinally, using its byssus, with its anterior part towards the head of the host. The mantle of the commensal bivalve has wide anterior (branchio-pedal) and narrow posterior (exhalant) apertures. In the living organism, the extended anterior edges of the mantle protrude from the shell and are inserted into the host's filtering basket, which is formed by the setal rows of the first two pairs of pereiopods and utilized for intercepting suspended matter. By beating its pleopods in a U-shaped burrow, the filter-feeding Upogebia shrimp creates water currents, which are also utilized by the commensal bivalve for filter-feeding. The shell length of the commensal bivalve was in proportion to the host's carapace length. This suggests that the veliger larva attaches to a young host and grows, thus maintaining the host-commensal morphological matching. The bivalve is a hermaphrodite and individuals of >8–5 mm in shell length were already producing eggs. Anatomical observations suggest that P. ohshimai is most closely related to the Montacutidae in Galeommatoidea.

The rates of gastric evacuation and return of appetite in adult Scyliorhinus canicula at 15°C were quantitatively assessed by serial x-radiographs of fish fed a moist diet containing radio-opaque glass beads, and by re-feeding trials. The evacuation of food from the cardiac stomach of dogfish was exponential in nature. Dogfish were fed small (~26 g of squid diet per fish) and large (~55g of squid diet per fish) meals and greater relative instantaneous rates of emptying occurred after consumption of small meals (k=0–0215) than larger meals (k=0·0086), indicating that the pattern of emptying was dependent on the degree of stomach fullness. There was inverse proportionality between rates of gastric evacuation (GE) and return of appetite (RA) after consumption of similar sized meals, with instantaneous rate coefficients being similar in magnitude (GE, k=0·0086; RA, k=0·0063). These results suggest that the rate of gastric evacuation is closely correlated with the return of appetite in S. canicula. An hypothesis is forwarded describing the possible physiological role of gastric evacuation rate in appetite regulation.

An investigation into the euphausiids in the Plymouth waters was undertaken on account of the fact that on examining adult Herring for food it was found that Nyctiphanes Couchii (Bell) was of great importance, and occurred in enormous numbers in a large proportion of the Herring caught in the earlier half of the period of the Herring fishery.

Hemigrapsus crenulatus is an abundant and frequent decapod crustacean inhabiting estuarine environments, where it must tolerate large shifts in salinity. The present study evaluates the effect of salinity (5, 13, 21 and 30 psu) on the adult physiological processes related to the energy balance. The growth potential (SFG) and the respired oxygen:excreted nitrogen ratio were used as indices of stress. Ingestion, excretion and respiration rates showed a significant dependence on salinity, being higher at low salinities. The assimilation efficiency remained constant along the studied salinity gradient. The assimilation and ingestion rates were inversely related with the salinity. Given this scenario, the growth potential remained constant within the studied salinity gradient, as did the oxygen:nitrogen ratio. The results suggest that the increased energy losses at low salinity due to respiration and excretion are compensated by an increment in the ingestion rate, contributing to the success of H. crenulatus in dynamic habitats such as estuaries.

The activity of the following planktonic animals has been observed at hydrostatic pressures up to 500 atm: Gigantocypris mülleri, Conchoecia hyalophyllum, C. macrocheira, C. rhynchena, Parathemisto sp., Megacalanus longicornis, Euaugaptilus magna, Pareuchaeta gracilis, Pleuromamma robusta, Anomalocera patersoni, Euphausia krohni, Acanthephyra pelagica and Amalopeus elegans. Respiration of Gigantocypris and Systellaspis debilis was also measured at pressure.

Cephalopod molluscs have attracted little attention as potential hosts for digenetic trematodes. Though none appears to serve as a first intermediate host, many do act as second intermediate, paratenic, or final hosts. Hence, they probably play a more important role in the life history and dissemination of Digenea in the marine environment than is generally recognized.

Energy values of many cold-water marine invertebrates are available (see Wacasey & Atkinson, 1987 and Brey et al, 1988), but energy values of temperate-water marine invertebrates have not been systematically investigated. In an attempt to determine the energy content of the macrobenthic communities from the bay of Morlaix (western English Channel), the caloric values in a large number of species living in these communities has been measured. This paper is presented as a contribution to the knowledge of the energy content of macrobenthic invertebrates from a temperate sea.