Sea food is very rich in lipids. The brown shrimp, Crangon crangon is a most popular and very valuable taxon in the White Sea, in the Mediterranean and in the Black Seas. The aim of this study was to determine the seasonal variations of lipids in C. crangon muscle tissue using gas chromatography–mass spectrometry. The lipids were separated into groups: neutral lipids (triacylglycerols, free fatty acids, sterols) and polar lipids (phospholipids), by high performance liquid chromatography with a laser light-scattering detector. Fatty acids were identified using the GC-MS technique. The mainly fatty acids were 16:0, 18:0 (saturated FAs), 16:1, 18:1 (monounsaturated FAs), 20:4 (ARA), 20:5 (EPA) and 22:6 (DHA). The largest amounts of fatty acids in the muscle were observed in spring; these were the result of collecting food after winter and before reproduction. The muscle lipid content was 32.2 ± 1.8 mg g−1. The summer was the poorest season and the lipid value was 7.7 ±0.4 mg g−1. The levels of muscle neutral lipids (NL) oscillated between 80% (autumn) and 90% (spring). The temperature and salinity has a significant influence on content and profile of fatty acids. This work will help to understand the biology, the seasonal variation in lipid mass, lipid classes content and fatty acids profile in the abdominal muscle of C. crangon.

Throughout lactation, pups of pinnipeds regularly vocalize, including during interactions with their mother. In all studied species of otariids and in some phocids, these calls exhibit sufficient acoustic variation for individual recognition. As female grey seals Halichoerus grypus (Pinnipedia: Phocidae) often pup in dense colonies, and regularly leave their offspring alone to go to sea, the selective pressure for mutual vocal recognition between mothers and pups could be high. To investigate call variation in pups of this species, 170 calls of ten individual pups were analysed. Out of seven acoustic features studied, location of maximum signal strength, the number of harmonics and the frequency and strength of the fundamental show the highest individuality. However, the apparent infrequent use of pup calls during mother-pup reunions suggests that vocal signals may not play the major role in pup discrimination by female grey seals, as observed in other phocids which females do not vocalize to their pup.

Natural marks occurring in cetaceans are used to measure population parameters, social structure and movements. However, the changeable nature of these marks can originate bias in these estimates. The aim of this work was to calculate abundance and prevalence of 28 mark types observed in common minke whales and white-beaked dolphins photographed in Icelandic waters for 11 years (2002–2013) in order to identify reliable markings which could be suitable for capture-mark-recapture studies. In the common minke whale subsample the most prevalent occurring marks were cookie-cutter shark bite, notch and lamprey bite, and herpes-like lesions and blisters were the most abundant. White-beaked dolphins had notch, fin patches and fine scrape as the most prevalent, and black mark and fine scrape were the most abundant. Loss and gain rates were also estimated resulting in eight mark types with no losses in common minke whales including fin outline and injury marks. In white-beaked dolphins there were 13 mark types with null loss rate among which there were notch, distinct notch and amputation. Our findings confirm that fin and injury marks are among the most accurate features to use for capture-mark-recapture studies as noted for other cetacean species. We also suggest including cookie-cutter shark bites for common minke whales and fin patches for white-beaked dolphins due to their low loss rate. These two mark types were amongst the most prevalent in both species, so their addition will be pivotal in increasing the power of analysis conducted using photo-identification data obtaining more accurate population estimates.

A new species of lugworm Arenicola defodiens sp. nov. (common name ‘black lug’ or ‘runnydown’) is described from 148 specimens taken from intertidal sands around South Wales. Comparisons are made with the well-known and generally more common lugworm Arenicola marina (L.). To aid in diagnosis, a table illustrating differences in the genetics, ecology and morphology is also provided.

Numerous studies of their population genetics have reported incipient reproductive isolation among sympatric populations of the common intertidal beadlet anemone Actinia equina. This has lead to certain morphs being raised to specific status. A study of the nematocysts of the green sea anemone Actinia prasina and three genetically isolated morphs of A. equina was undertaken to establish that mean nematocyst length could act as diagnostic phenotypic characters within a morphologically variable group. The results support genetic and ecological evidence for the specific status of the three red/brown coloured morphs of A. equina. The data are discussed with respect to the ecology of Actinia and concepts of species, but more work is required before the specific status of A. prasina can be confirmed.

Dolphinfish (Mahimahi) are a high-demand resource for sport and coastal fisheries, mainly in the Pacific Ocean. Due to their economic and ecological importance, studies of their biology are very important to understand their function in ecosystems. We used stable isotope and stomach content analyses to determine the most important prey of the common dolphinfish, as well as the trophic level of this species in two areas of the southern Gulf of California. Stomach contents of 445 specimens were analysed. Using both techniques, we found that the most important prey for dolphinfish in the southern Gulf of California were three invertebrate species followed by fish. This contrasts with results from other authors who found that this species was mainly piscivorous in other locations. Stomach content analysis indicated differences in prey biomass by area, season and size class. The isotopic analysis did not show significant differences between seasons or sexes. Both stomach contents and stable isotope analyses showed that although this predator consumed a wide prey spectrum, only a few prey items made up the bulk of the diet, which resulted in a low SD in δ15N values and low Levin's index values. We conclude that this fish is an opportunistic predator that may consume a wide prey spectrum, but that it mainly consumes prey that are abundant in the area, such as crustaceans and cephalopods in the Gulf of California.

The common whelk, Buccinum undatum L., was selected as a model host-parasite system in a seasonal study at an ‘accumulating’ sewage-sludge dump-site in the Firth of Clyde, Scotland, where marked spatial concentration gradients exist for a variety of trace contaminants in the sediments. A total of 2808 whelks was examined from seven sites over 18 months. The prevalence of larval digenean parasites increased significantly with distance from the dump site from approximately 2% on its periphery to 15.1% at a reference site 3 km from the centre. At a second reference site, 13 km from the dumping area, 19.7% of Buccinum were parasitized. The effects of site, season, sex and parasitism on growth and condition of Buccinum and exposure to sewage sludge on the age-prevalence relationship and host response to infection were examined. Age-frequency distributions of Buccinum were used to compare various sources of mortalities (natural, fishing, pollution and parasite-induced). Patterns in parasite prevalence recorded at the dump site were not correlated with any natural environmental or host-related factors that were examined. The gradient in parasitism in Buccinum is considered to result principally from the toxic effects of trace metals on the miracidium, reducing parasite transmission to the molluscan host. The Bucrinum-parasite system may therefore provide a sensitive and valuable biologically-based index of the dispersal of these contaminants around the sewage-sludge dump-site, and may have wider applications for marine environmental monitoring.

Fourteen species of benthic invertebrates, found to be indicators of hydrographic conditions by Blacker (1957), were recorded during research cruises between Finmark and north Spitsbergen during the summers of 1978, 1979, 1980 and 1981. The distributions were compared with those found during surveys carried out between 1949 and 1959.Both Atlantic and Arctic species were found to the north of Bear Island and along the west coast of Spitsbergen, and the temperature ranges at which they were found were greater than those found by Blacker (1957).

Introduction

During the past century the annual mean temperature of the Arctic regions has undergone a considerable change. The warming of the regions began about 1885 (Willett, 1950) and peaked around 1938, when the mean air temperature of Spitsbergen was nearly 6 °C warmer than at the turn of the century (Hoel, 1953). The warming of the seas in the region seems to have started later - Jensen (1939) suggests 1917 - and sea temperature changes were detected north of Spitsbergen in 1921 (Schokalsky, 1936). This warming resulted in the reappearance of cod in great quantities on the Bear Island Bank, after the absence of any sustained quantities for about 40 years (Blacker, 1957).

The marine benthos of Svalbardf was surveyed during the latter part of the last century and the first half of this century (1878–1914,1923–31) when the benthos was recorded during several cruises in the region (see Blacker (1957) for review). The benthos was again recorded between 1949 and 1955 (Blacker, 1957) and 1955 and 1959 (Blacker, 1965); see Fig. lA.

The role of sandy beaches as nursery areas for 0-group anchovies (Teleostei: Engraulidae) was investigated in a tropical bay, south-eastern Brazil. Spatial and temporal (diel and seasonal) changes in fish abundance and environmental influences at two beaches were assessed, one located in the outer zone, and the other in the inner zone of Sepetiba Bay. The two sites were sampled quarterly at the same time (0800, 1100, 1400, 1700, 2000, 2300, 0200 and 0500 hours) over a 24 h cycle by beach seine with three replicates, between winter 1998 and autumn 1999. Environmental variables of water temperature, salinity, and transparency (as % depth) were taken at each fish-sampling occasion. Five species in three genera (Anchoa tricolor, A. januaria, A. lyolepis, Cetengraulis edentulus, and Lycengraulis grossidens) were identified. Anchoa tricolor and A. januaria were the most abundant species and indications of spatial separation were detected, with A. tricolor being more abundant in the outer bay (higher salinity and lower temperature), while A. januaria, in the inner bay (lower salinity and higher temperature). Overall, young-of-the-year Engraulidae peaked during the day, perhaps an adaptation to avoid competition with other abundant species which peak at night. Maximum densities of anchovies due to 0-group influxes were found in spring and paucity in summer. Spatial segregation to optimize resource uses and daily habits adapted to take advantage of the rich planktonic bay waters seems to be the strategy developed by these closely related species to use the area during early life cycle. Their high abundances suggest the suitability of the sandy beaches as nursery areas.

The inter-organ nutrient transport in echinoderms has presented an interesting but as yet unresolved problem for more than eighty years. During that time two systems have been proposed as candidates for the transporting medium or transport route, namely the coelomic fluid and the haemal system.

The combined effects of temperature and salinity on the survival and development of larval and juvenile Palaemon serratus from the west coast of Ireland were investigated. Survival over time was measured at thirty combinations of temperature and salinity ranging from 10–19°C and 9–34‰ in a fully factorial design. Salinity had a stronger influence than temperature on survival at all larval stages except stage V. For juveniles the main effect changed from temperature between 100 and 200 degree days to salinity between 200 and 600 degree days and temperature between 600 and 800 degree days. Estimates of time taken to 50% mortality showed that juveniles tolerated lower salinities for longer periods and exhibited optimal salinity values which were 3‰ lower than larvae, at temperatures between 10 and 15°C. Larval stage durations were found to be influenced by temperature but not salinity. Comparison with published data suggests that populations of P. serratus have adapted to local conditions of temperature and salinity. The results presented here have practical implications for fisheries assessment and management, as the incorporation of environmental effects into stock–recruitment models can improve their predictive capacity.

1. Diameter measurements of Rhizosolenia styliformis from the Antarctic, the subtropical Atlantic and Pacific Oceans and from the North Sea and neighbouring waters have made it appear necessary to set up two varieties, oceanica and semispina, in addition to the type of the species R. styliformis. The type as I describe it has been called var. longispina by Hustedt, but elsewhere it has often been figured as the var. oceanica of this paper. Var. semispina is synonymous with the form represented by Karsten as R. semispina Hensen. It differs from R. semispina as drawn by Hensen and its synonym R. hebetata forma semispina Gran, but is thought likely to be linked by intermediates. If this is so R. hebetata may have to be extended to include and suppress R. styliformis, as var. semispina is linked to the type by intermediates. Var. oceanica has no intermediate forms and, if R. hebetata is to be extended, this variety should be established as a separate species.

2. Var. oceanica is absent from the southern North Sea and appears to be an indicator species related to oceanic inflow.

3. Auxospore formation was observed for the type in the southern North Sea in 1935 and biometric observations suggest that a period of 3-4 years elapsed between the production of auxospore generations in that area. Outside the southern North Sea for the type, measurements give no indication of auxospore generations occurring at intervals exceeding a year. While auxospore formation has been seen in var. oceanica from the Shetlands area samples of June 1935 and July 1938, this phenomenon has not been observed for var. semispina.

The body of Archidoris britannica contains very high concentrations of calcium and magnesium which appear to be combined mostly with CO3 and fluoride. The bulk of these materials are in solid deposits throughout the submucous tissue. Sodium chloride and potassium phosphate account for most of the residual mineral matter.

The mucus secreted by the body has an inorganic composition resembling sea water.

The visceral mass contains only one-tenth as much calcium and magnesium as the body. The predominating bases are potassium and sodium and the acid radicles are essentially chlorides and phosphates.

The structure of sessile epibiotic assemblages fouling the shells of farmed populations of the common Mediterranean mussel Mytilus galloprovincialis, a species known to be involved in ecosystem engineering processes, was investigated in the north Aegean Sea. Mussel samples were collected from three aquaculture installations and all sessile organisms were examined. Fifteen species were recorded, one macroalga and 14 macro-invertebrates. Four colonial species covered up to 20% of the mussel shell. Among solitary organisms, polychaetes dominated followed by barnacles. The diversity of sessile epibionts associated with farmed mussel populations was comparable to that observed on natural mussel beds in contrast to their abundance/cover, which was higher in the former, possibly due to the higher trophic status in the farming areas. The structure of epibiotic assemblages exhibited limited variability at the spatial scale, in general. On the contrary, strong temporal variability with decreased diversity and abundance/cover values during the cold period of the year was assessed, in accordance with the life cycles of species involved and prevailing environmental conditions. Mussel epibionts appeared to have a negative impact on their basibiont since a reduced condition index was detected; however this impact was rather weak and further data are required to generalize the consequences of epibiosis on farmed mussels.

Length-weight relationships were calculated for 48 fish species from İzmir Bay in the Aegean Sea, Turkey. A total of 3584 fish specimens were captured with beach seine, handline, fyke net, scoop net, castnet and trammel net in 2010–2014. The sample size ranged from three individuals for Squatina squatina to 140 for Mugil cephalus. R2 values varied between 0.95 for Pomatoschistus bathi and 0.99 for Argyrosomus regius, Chelon labrosus and Mugil cephalus. All regressions were highly significant (P < 0.001). Values of the exponent b in the length-weight regression (W = aLb) ranged from 2.750 for S. squatina to 3.514 for Syngnathus acus and the median value was 3.134 with 25–75% of the values ranging between 3.030 and 3.218.

Comparative ultrastructural features of the ovary and vitellogenesis have been described for six shallow water and four bathyal species of sea cucumbers representing four major holothuroid orders. Ovarian structure is similar in all ten species except for features of the peritoneal cells of the outer layer and the follicular inner epithelial cells surrounding the developing oocytes. The peritoneal cells vary from monociliated squamous or cuboidal cells to large columnar cells. Ultrastructural evidence suggests that these cells might be capable of incorporating materials from the perivisceral coelom. The follicular inner epithelial cells of two deep-sea species resemble podocytes, a feature previously unre-ported in holothuroid ovaries. It is suggested that these cells function to increase nutrient exchange between the genital haemal sinus and the oocyte during vitellogenesis. In all ten species, the oocytes appear to participate in yolk synthesis through the interaction of the Golgi complex and rough endoplasmic reticulum. The similarity in the ultrastructural features of vitellogenesis suggests that the process of yolk synthesis has been highly conserved in holothuroids. Endocytotic activity was detected in seven of ten species but it is uncertain if this is directly related to vitellogenesis. Cilia and intracellular structures resembling striated ciliary rootlets were observed in the oocytes of four of the ten species studied. The significance of this finding is unclear but could indicate that germ cells have a somatic cell origin.

An area in the English Channel of about 30 x 45 miles centred on a position about 25 miles south of Plymouth was surveyed twice in 1959 and six times in i960. Temperature and salinity were measured at 0, 10 and 50 m, and phosphate and silicate concentrations at 10 and 50 m.

Lower temperatures were usually found near the coast, though the converse was observed in October i960.

Isotherms generally ran east-west in winter and north-south in summer.

Salinity was usually lower near the coast, but not in the summer.

Density contours generally resembled those of temperature, and suggested an eastward water movement in winter. In summer they suggested an offshore movement at the surface and an onshore movement of the deeper water.

In winter the distribution of phosphate and silicate resembled that of salinity, high values of nutrients corresponding to low salinities.

In summer the depth of thermocline was greater to the west

The properties of the water were so variable from place to place, and changes in them so rapid, that it is difficult to accept results from station Ei, or any other single station in the area, as typical of the whole.

Largely as a result of experiments made in 1951, sands were classed as attractive, neutral or repellent (Wilson, 1953 a); but only after the 1952 experiments had been completed did it become reasonably certain that the sands in which the larvae of Ophelia bicornis Savigny readily settle carry an attractive factor apparently distinct from a repellent one present in sands in which they will not settle (Wilson, 1953 b). Whilst the precise natures of the factors were uncertain, it seemed probable that they both derive from organic activity. The 1953 breeding season was devoted to an attempt to obtain more information about the attractive factor.

The maritime basin of the Ranee occupies one of the largest rias of northern Brittany (France) and since 1967, has been the location of a tidal power station. At a high tide height of 13.5 m above chart datum the basin occupies an area of 22 km2 within which Retière (1979) recognized a maritime part of about 17 km2 in extent, where bottom salinities range from 30 to 35‰, an estuarine part with salinities between 20-30‰,, of about 4 km2 and an inner estuary of limited area (1.5 km2) and reduced salinities (less than 20‰).

It has been shown by Eeid (1930) that the salinity of the water retained in a sandy foreshore at low tide may be considerably higher than that of a stream of brackish water flowing over it. A few similar observations have been made on the salinity of the water held in the muddy foreshore of the estuary of the River Tees.