Two populations of Clibanarius erythropus from Mediterranean and Atlantic rocky shores were studied to provide data on morphometry, population structure and shell use under different environmental contexts. Hermit crab sex and size were analysed as well as genus, dimension and status of the inhabited shells. A comparison between the two populations gave particular emphasis to the morphological and eco-ethological plasticity of this hermit species.

The stomach contents from a male sperm whale, Physeter macrocephalus, first located floating a short distance off the south coast of Crete were examined. The remains within the stomach consisted almost exclusively of cephalopod mandibles, or beaks, though other material was found including a piece of rigid plastic mesh. Of the beaks found, 1714 were upper beaks and 2178 were lower beaks, that were used to identify the species. A total of seven species was identified, all of which have been previously recorded in the eastern Mediterranean though are rarely caught by man. Of these Histioteuthis bonnellii was found to be the most important species in terms of both weight and numbers. Although it must be borne in mind that the whale may not have followed its normal feeding habits prior to its premature death, an important insight into its prey items can be revealed. This is the first documented account of the stomach contents of a sperm whale from the Mediterranean, and helps to complete a global record of sperm whale diets.

Southward & Butler (1972) discussed changes in sea and air temperature in the Plymouth area this century, and showed that there was an increase from about 1900 to 1945 followed by a decrease. In the present analysis the data, updated to 1974, have been subjected to a more rigorous statistical treatment, made possible by the availability of a computer; inshore and offshore sea temperatures have been compared in greater detail, and sea-bed temperatures included. The results are described and discussed in relation to the biological changes that have been observed in the western English Channel during the same period. Data on rainfall and westerly weather have also been examined, and correlated with the temperature values.

According to the generally adopted view, all the proprioceptors of the leg articulations of decapod Crustacea respond to stretching or relaxation of the organs caused by joint movements or joint position. This view is based on anatomical and physiological studies made, originally, mostly on crabs. It has been found, however, that in other groups of Crustacea, such as Anomura and Macrura Reptantia, some of these receptor organs are anatomically related to structures on the exoskeleton. This type of receptor organ, examined in Palinurus vulgaris Latreille, Homarus gammarus (L.) and Pagurus bernhardus (L.), is the main subject of the present paper. In the course of this work some observations have been made on other proprioceptors, particularly those in the ischiopodite-meropodite articulation, and these too are reported below. The organs in the coxal region, the special structure of which was the subject of previous investigations (Alexandrowicz & Whitear, 1957; Alexandrowicz, 1958, 1967), are not included.

At Station E I,22 sea miles south-west from Plymouth, the winter maximum for phosphate, representing the stock available for plant growth in the following spring, averaged 0·67 mg.-atom/m.3 for the winters 1923–4 to 1928–9 and only 0·47 mg.-atom for 1930–1 to 1937–8. This fall in phosphate shows a close correlation with the abundance of summer-spawning young fish (Russell). Since water containing similar low phosphate appeared to occupy the English Channel in 1916 (Matthews), the inflow of warm Atlantic water in the autumn of 1921 may well have brought with it the relatively rich phosphate found in the 1920's.

The impoverishment of phosphate around 1930 runs parallel with a decrease in the easting of the residual current at the Varne lightship in the Straits of Dover (Carruthers).

On the basis of spring phosphate consumption, the years may be classified in order of productivity:

Nuclear 18S rRNA gene sequences of oyster shell borers, Polydora websteri, P. calcarea and P. haswelli (Polychaeta: Spionidae), were determined for the first time. A wide range of morphological variation, particularly with regard to pigmentation, is observed among these three species. This variation was characterized at the species level. Black pigmentation pattern on the palps is suggested to be a key characteristic for species determination. Polydora websteri and P. haswelli were sister species. This is the first record of P. calcarea from Japan and Australia and P. haswelli from Japan.

The production or emission of light is under nervous control in many marine animals that have a differentiated nervous system. The nature of this control is a field of neuro-effector physiology that has been little explored, but one which could advance considerably our knowledge of the behaviour and functioning of luminescent marine animals. Nervous control of luminescence is achieved in diverse ways in different animals, namely, by squeezing forth a pre-formed secretion through muscular contraction, as appears to take place in Cypridina; by exposing a continuously luminescent organ through rotation or by movement of shutters, as in the teleosts Photoblepharon and Anomalops; by initiating cellular changes that lead to intracellular luminescence, for example in the photophores of the shrimp Acanthephyra debilis; and by directly activating light gland cells to secrete. The last method is a special example of nervous regulation of glandular secretion, and is the process occurring in the polychaete Chaetopterus (Dahlgren, 1916; Harvey, 1920, 1940).

Biochemical changes during the reproductive cycle of Aristeus antennatus (Crustacea: Decapoda) on the Portuguese south coast were investigated. Proximate chemical composition, lipid classes, fatty acid profiles, glycogen and cholesterol content were determined in the muscle, ovary and hepatopancreas (HP) during a period of one year (October 2000–September 2001). Gonadosomatic index (GSI) increased significantly in June and July and during the maturation process. Hepatosomatic index (HSI) also increased throughout the ovarian maturation. A positive correlation between lipid levels in the ovary and GSI (r=0.53, P<0.05) and HSI (r=0.30, P<0.05) was found. The muscle showed very low lipid levels and higher percentages of polar lipids. Higher proportions of neutral lipids, mainly triacylglycerols, were observed in both ovary and HP. Both ovarian and HP cholesterol increased with maturation. Protein and glycogen content in the muscle, ovary and HP did not vary as a function of ovary maturity stage. From the different tissues analysed, the glycogen is mainly stored in the HP and to a lesser extent in the muscle. In both ovary and HP the major fatty acids were 16:0, 18:1(n-7), 18:1(n-9), 20:5(n-3) and 22:6(n-3), and significant increase in the levels of monounsaturated fatty acids were observed in ovary during sexual maturation, which indicates these compounds as the major sources of energy during embryonic and early larval development.

Development of the olfactory system in anemonefish embryos of the species Amphiprion melanopus was examined from day six post-fertilization, until hatching (day nine). An olfactory placode with receptor cells lining the epithelium and nerve axons from the placode into the olfactory bulb, was observed on newly hatched embryos. In addition, two different secondary bilateral receptor systems were found. These findings may firstly support the anemonefish host imprinting hypothesis, and secondly indicate that the ontogenetic timing of this imprinting mechanism occurs towards the end of the embryonic development.

Seagrass beds are common features of coastal ecosystems worldwide, and their associated infauna are often more productive and diverse than in unvegetated habitats. Little is known, however, about the ecology of meiofaunal communities living in seagrass sediments. We compared the abundance and biomass of sediment meiofauna inside and outside an intertidal Zostera muelleri bed in southern New Zealand to assess the impact of seagrass cover on meiofaunal distribution. Nematode community structure, diversity, and feeding groups were also compared between habitats and sediment depths (0–2, 2–5 and 5–10 cm) to evaluate the effect of seagrass on nematode communities. Meiofaunal biomass was significantly higher inside than outside the Z. muelleri bed, but secondary productivity inside the bed is likely to have been limited by the availability of labile organic matter. There were significant differences in nematode community structure between unvegetated, sparsely vegetated, and densely vegetated sites (102 m scale), as well as between sediment depths (cm scale). No significant differences were found in depth-integrated (0–10 cm) nematode diversity between sites, but vertical gradients in diversity differed between vegetated and unvegetated sites. Epistrate feeders were the most common feeding group in unvegetated sediments whereas most feeding groups were common inside the seagrass bed. Findings from this study indicate that seagrass beds can have a marked impact on infaunal structure and function over small spatial scales through their effect on sediment characteristics and organic matter input. Some unexpected trends observed in the present study, i.e. low meiofaunal biomass at the vegetated sites, and lower abundance of copepods inside than outside the seagrass bed, suggest that the nature of seagrass–invertebrate interactions may depend on habitat characteristics and the identity and ecology of species considered.

Two nematode species living in association with chemoautotrophic prokaryotes were found in two deep-sea canyon/channel systems, the Whittard Canyon and Gollum Channels, north-east Atlantic. Parabostrichus bathyalis gen. nov. sp. nov. (Desmodorida: Desmodoridae: Stilbonematinae) relates to Eubostrichus Greeff 1869 but differs in having well-developed paired dorso-caudal apophyses of the gubernaculum, small pre- and postcloacal latero-ventral papillae with short apical setae, elongate tail with slender posterior portion, and the absence of thorn-like setae (porids) in males. Body of P. bathyalis is loosely covered with elongate cells of prokaryote ectosymbionts. Astomonema southwardorum Austen et al. 1993, originally found at a methane seep pockmark in the North Sea, constitutes a significant portion of nematode communities in certain areas of the deep-sea canyon/channel systems. Taxonomic difficulties within Astomonematinae are discussed in light of the character state of paired male gonads discovered in A. southwardorum. Canyon populations of A. southwardorum are characterized by frequent loss of part of the hind body and wound healing posterior to the vulva in females. Both species tend to occur in deeper subsurface layers of the bottom sediment. Abundance of the nematode species associated with aggregations of ectosymbiotic (Parabostrichus) and endosymbiotic (Astomonema) chemoautotrophic bacteria may indicate reduced conditions at sites in these deep-sea canyons/channels and suggests a potentially substantial ecological role for chemolitotrophic fauna there.

The respiratory rates of four species of planktonic copepods were measured. In two of the species measurements were made with two copepodite stages, and with adult male and female specimens.

The rate for Calanus finmarchicus Stage V at 17°C. was found to be 0·52 μl./cop./hr., a figure which agreed with previous measurements.

For all the species and stages studied the respiratory rate was found to be closely proportional to the length to the power of 2·2.

The relevance of such measurements to conditions in the sea is briefly discussed.

The contribution of non-loricate ciliate assemblage to the ecological pattern of a ciliated protozoan community was studied based on a 1-year (June 2007–May 2008) dataset collected from Jiaozhou Bay, northern China. Samples were collected biweekly from five sampling sites. Results showed that: (1) the non-loricate ciliate assemblages were the primary components and significantly correlated with the total ciliate communities in terms of species number, abundance and biomass; (2) the ecological pattern of non-loricate ciliate assemblages was significantly related to that of both total ciliate communities and variations in environmental variables; and (3) spatio-temporal variations in biodiversity (richness, diversity and evenness of species) indices of non-loricate ciliate assemblages were significantly correlated with those of total ciliate communities and the environmental conditions, especially nutrients nitrate nitrogen, nitrite nitrogen and soluble reactive phosphorous. These results suggest that the non-loricate ciliates are a primary contributor to the ecological pattern of total ciliate communities and might be used as a potential bioindicator for bioassessment in marine ecosystems.

During the studies on sole recruitment in the Bay of Biscay, transport process attracted considerable attention and led to important research on migration and dispersal. The last step to complete the study of the spatial component of the life cycle of sole in the northern part of the Bay of Biscay is the offshore migration of young adults towards the spawning grounds. the present study deals with this pre-spawning migration. the main question concerns the kind of linkage between nurseries and spawning grounds. The principal results are based on extensive tagging experiments carried out in autumn 1992 in two distinct nursery grounds, Bay of Vilaine and Pertuis (4620 soles of 2-group and older). One year later (January 1994) catches of tagged individuals reached 18.1% and 11.9% of the initial samples, respectively. From September to February a 50-km net displacement of the centre of the population was observed towards the offshore deeper area. A small trend to move onshore appeared in spring. In parallel with these net movements individuals were dispersed around the centre of gravity of the population. This dispersion was higher in a direction parallel to the coast. Individuals from different nurseries were mixed over the same spawning areas of the Bay of Biscay, and some individuals were also captured in and close to the English Channel. Changes in distribution were in phase with environmental changes and some elements concerning topographic preferences also appeared. Some evidence for orientation was observed but random dispersal seemed more important. No particular link between a given nursery and a spawning ground in the vicinity appeared.

The isopod genus Jaera Leach (Crustacea) is a common component of the fauna in estuaries (Green, 1968; Jones & Naylor, 1971; Naylor, 1972; Jones, 1974). The members of this genus are able to survive low salinity (Jones, 1972a; Harvey, Jones & Naylor, 1973) by active control of the osmotic concentration of the body fluids above that of the external environment (Jones, 1972&; Forbes, 1974). While it has been well established that the crustacean gill is the site of the transport system involved in osmoregulation (Koch, 1954; Shaw, i960; Bielawski, 1964; Croghan, Curra & Lockwood, 1965; Quinn & Lane, 1966), there have been few studies on the fine structure of this organ (Copeland, 1968; Copeland & Fitzjarrell, 1968; Bielawski, 1971; Fisher, 1972; Talbot, Clark & Lawrence, 1972; Lockwood, Inman & Courtenay, 1973). The present paper describes the structure of the gills of Jaera nordmanni (Rathke) and relates the role of the various elements observed to the physiological functioning of the gill.

An examination was made of the stomach contents of plaice post-larvae taken from the Southern Bight spawning ground in the spring of 1950. They were found to be feeding mainly on a soft-bodied prey, which left characteristically shaped faecal pellets and an undigested matrix vesicle as the only evidence of its nature. Pellets from the post-larvae compared closely in shape with those of Oikopleura dioica, found in the plankton of the spawning area during the period of post-larval development.

In 1951, undigested Oikopleura were seen in the oesophageal regions of a few dissected specimens, in addition to typical indigestible remains in a large proportion of the total feeding post-larvae examined.

Records for 1946 suggest a similar exploitation of the Oikopleura population by plaice post-larvae, although the phenomenon was not repeated in 1947, when inclement weather may have interfered with the annual outburst of this prey.

The phenomenon of food selection by plaice post-larvae is discussed, with special reference to the part that vulnerability may play in limiting the number of species of prey available as food.

A feature of this and other investigations on post-larval feeding, was the occurrence of a high proportion of empty stomachs. An experiment designed to test a regurgitation hypothesis, revealed the existence of a marked diurnal pattern of feeding activity, apparently influenced by light conditions. The importance of light in feeding behaviour was confirmed by tank experiments. In this investigation a large proportion of the empty stomachs encountered can be explained by reference to diurnal fluctuations in feeding activity, supporting the view that plaice post-larvae are visual feeders.

The great scallop Pecten maximus (Bivalvia: Pectinidae) supports a substantial European fishery with a recent history of declining catches caused by over-exploitation. The sustainable exploitation of shellfish populations requires knowledge of the extent to which commercial grounds are reproductively self-sustaining or supplied with larvae originating from further afield. The degree of genetic differentiation between locations can provide important indirect evidence, reflecting the pattern and scale of effective larval dispersal. Pecten maximus were sampled from five locations around the Isle of Man, from Mulroy Bay (Ireland) and from Plymouth. Restriction-site variation was investigated in two PCR-amplified mitochondrial DNA fragments of 2 and 3 kb, respectively. Haplotype and nucleotide diversity within populations, and nucleotide divergence between populations, were calculated. Mean nucleotide sequence divergence was corrected for within-population polymorphisms and visualized by UPGMA cluster diagrams. Molecular analysis of variance (AMOVA) was carried out. Results showed low levels of population differentiation. Slight but significant differentiation between Isle of Man populations was revealed, with East Douglas appearing distinct from the remaining Manx locations. The analyses also indicated the distinction of Mulroy Bay from the other populations, and the lowest genetic variability was recorded from this enclosed habitat. This probably reflects the relative isolation of Mulroy Bay, whereas dynamic hydrographic conditions in the Irish Sea and the Channel may generally ensure extensive mixing of the planktonic larvae.

No account exists of the mechanism of food collection of nudibranch larvae, and, in fact, it has been considered unlikely that feeding does take place in these forms. Thorson (1946, p. 275) states ‘Nudibranch larvae will normally take no—or only little—food from the plankton’.

This study reports on the transfer of heterotrophic bacteria from parental tissue to oocytes in the Mediterranean bacteriosponge Corticium candelabrum (Homosclerophorida) and the description of the successive locations of the microsymbionts during embryo development through transmission and scanning electron microscopy. Eight different types of symbiotic bacteria are described morphologically. These eight bacteria morphotypes are found in both adult individuals and larvae. Symbiotic bacteria are transferred to oocytes, but not to spermatocytes. Bacteria are first located at the oocyte periphery below a thick collagen layer and then they migrate to the oocyte cytoplasm, forming spherical clusters. After cleavage, the bacteria can be found in the free space between blastomeres but mainly accumulate at the embryo periphery below the follicular cells that surround the embryo. Once the blastocoel is formed, the symbiotic bacteria move to this central cavity where they actively divide by bipartition, increasing their number considerably. Many examples of phagocytosed bacteria in the proximal zone of the larval cells are observed at this stage. Consequently, bacteria may represent a complementary source of energy for free larvae and settlers before they are able to capture food from the surrounding water.

Living marine resources have strong links with human health and well-being that are complex, still not well understood and that are being modified by global change. This review attempts to illustrate how fishing activities, aquaculture and climate change are challenging these connections and the consequent health risks and benefits posed to citizens. Although global change may provide some positive aspects for human health locally, such as new sources of omega-3, overall it will exacerbate existing seafood security and safety concerns. Unsustainable fishing and aquaculture practices, and climate change, particularly sea warming, ocean acidification and changes in riverine runoff, are threatening not only the protein and fish oil/omega-3 supplies available for consumers, but also raising ecological and health concerns associated with the increase of contaminants, microbes and biotoxins. In this context, we propose a number of management measures that could mitigate the negative effects of global change on seafood, and hence on human health and well-being.