A laboratory study simulating herbivorous feeding was carried out with the marine crustacean Neomysis integer (Leach) and the dinoflagellate Scrippsiella trochoidea (Stein). Analyses of the total fatty acids, sterols and fatty alcohols in the food and faecal material, and in the animal tissue, have allowed the detailed changes in the dietary lipids during feeding to be characterised.

The results show this feeding leads to a net decrease in total lipid in the material passing through the gut of the animal, particularly due to the bioassimilation of fatty acids. All fatty acid saturation classes are assimilated but the mono-unsaturated and particularly polyunsaturated fatty acids are preferentially assimilated over others. Herbivorous feeding does, however, lead to the quantitative and relative increase in ‘bacterial’-type odd C number branched-chain fatty acids in the faecal material.

Slope Water anticyclonic Oceanic eDDIES (SWODDIES) are typical mesoscale features of open-ocean waters of the southern Bay of Biscay which usually develop in winter by shedding from the seasonal poleward current flowing along the northern Spanish slope. These eddies have been intensively studied from the physical perspective. However, their effect on the distribution of biological properties and on the functioning of the pelagic ecosystem has not been assessed so far. To this aim, a sea-truth, multidisciplinary and comprehensive study of a SWODDY was carried out in summer 1998. The eddy, radius of ≈50 km, was initially centred at 45·5°N 6·0°W, being characterized by a relatively homogeneous core of water in the centre of the eddy extending from 80 to about 200 dbar. In the central region of the core, temperature (12·55–12·75°C) and salinity (≈35·70) values were higher than outside the eddy. The optical properties of the eddy also differed from those of the surrounding waters. A distinct biological signature was found associated with the eddy. Depth-integrated chlorophyll-a concentrations were 25% higher at the eddy centre where upward doming of the seasonal pycnocline (up to 30 dbar) occurred. Enhanced phytoplankton biomass was related to a higher contribution of >10 μm cells, mainly represented by diatoms and chrysophyceans. Phytoplankton and mesozooplankton species composition in and outside the eddy differed significantly reflecting the coastal origin of the water parcel trapped by the eddy. The sharp modification of the planktonic community composition, biomass and associated size-structure caused by slope water oceanic eddies are likely to exert a significant effect upon the upper trophic levels of the pelagic ecosystem of the southern Bay of Biscay.

The results of decapod lipid analyses have shown that females and gravid females generally contain high levels of monounsaturated acids and that the eggs of some of these decapods are composed mainly of phospholipid and triglyceride. These are probably present mainly as energy reserves. The percentages of saturated fatty acids are not found to vary with either maturity or sex, whereas the composition of the polyunsaturated acids are affected by both sex and maturity differences. Females are generally much lower in their content of polyunsaturated acids than juveniles and males, the males showing a greater requirement for 20:5 acid compared to the females.

For the euphausiids there is a slightly different picture, the monounsaturated acids appear as the stable fraction and for Euphausia krohnii the juveniles are similar to the females in their content of the polyunsaturated acids.

Neomysis integer is quite unlike the oceanic crustaceans showing a very specific difference in fatty acid composition between the males and females, the juveniles being rather intermediate in composition.

INTRODUCTION

Estimations of the growth of bivalves have traditionally been determined from measurements of animals collected on a regular basis from natural populations. Generally size frequency distributions have been analysed or growth rates estimated from measurements of the distances separating the annual rings (Hughes, 1970; Seed & Brown, 1978; Taylor & Venn, 1978). While both methods provide valuable information on shell growth, a more direct approach is to investigate experimentally the growth of individual animals held in cages and to follow the seasonal changes in the dimensions of their shells.

The queen scallop Chlamys opercularis (L.) is found in large numbers in areas around Great Cumbrae Island in the Firth of Clyde where they form the basis for a small local fishery. In 1979 the British Steel Corporation started operating a deep-water terminal at Hunterston unloading and loading iron ore and coal. It was envisaged that accidental spillage of material during transfer from the vessels to the shore might affect the queen scallop populations in the area.

Subjection to a variety of fluids confirms the presence of two non-living membranes roundv the developing eggs of Homarus. It also reveals that the outer membrane has the restricted permeability of cuticle and the inner membrane the free permeability of chitin.

The inner, chitinous membrane bursts when the egg contents swell; the outer membrane stretches, up to 50 % above its initial diameter, when the internal osmotic pressure rises. It also has considerable elasticity.

These properties of the outer membrane enable it to withstand the pressure to which the developing eggs are subjected and also to stretch during the development of the embryo, hence they have,considerable biological significance.The inner, chitinous membrane, which does not stretch, is probably ruptured and absorbed during development.

The larvæ of the Decapod Macrura occur throughout the year in the tow-nettings taken in Plymouth Sound; while during the summer months they form an important and conspicuous feature of the coastal plankton.

In only a few cases have their life-histories been fully worked out, owing probably to the difficulty of rearing the larvæ under artificial conditions; and the literature on the subject is consequently both scanty and scattered. It has therefore been suggested that a brief review of the larvæ already described, together with a few additional ones which have been identified during two years' examination of the Plymouth plankton, from 1917–1919, might be of some use to future investigators.

The object of the present paper is to enable future workers to see at a glance how far these forms have been investigated, and especially to facilitate the identification of the living larvæ from the tow-nets.

No attempt has been made to describe the appendages in detail, as such particulars can generally be found in the literature cited. A general outline drawing is given of the more important forms in their first larval stage, and a figure of the telson and uropods in the fourth or last larval stage is also shown.

As the coloration of the larva is often of great assistance in identifying the living animal, it is here described rather fully, and, whenever possible, the drawings and the colour notes have been made from the living larva. In cases where no direct observations were available the colour descriptions are quoted from other authorities.

The reproductive cycle of Bolinus brandaris (Gastropoda: Muricidae) was investigated. Specimens were sampled monthly from a site off Sant Carles de la Ràpita, in the western Mediterranean, between February 1999 and March 2000. A pattern was observed in the reproductive cycle, with two reproductive peaks (April and June–July). The first stages of gametogenesis began in September for males and November for females. Mature males were found from December to April and from June to July. Maximum ripening in females was attained at the end of June and during July, coinciding with the spawning season. In May, there was a resting stage in females, and for both sexes from August to October.

Males exhibited variation in penis length and vas deferens width related to the reproductive cycle. Sizes of both dimensions increased as maturation progressed. The variation was not found in imposex females.

It has been shown that there is a lunar periodicity in reproduction of P. opercularis near Plymouth in 1927-28. The ripening of sexual products corresponds with the full phase of the moon.

The condition and shape of the gonad changes with the development of the tissues.

The colour, too, of the hermaphrodite organ changes with development.

Black pigmentation has been observed on the gonad in thin-shelled P. opercularis, a phenomenon apparently due to actinic rays penetrating the thin shell.

The breeding season is from January to June inclusive.

The gut contents seem to show no appreciable difference either in quantity or in the natureof the food during a lunar month.

The moonlight has apparently no effect on the lunar periodicity in reproduction.

It is suggested that in the animal there is a physiological rhythm that causes the development of the gonad to coincide with the full moon of each lunar month

Wide-ranging surveys of the sea-bed and of its fauna may be made either from sledges or similar vehicles towed along the bottom, or from free-floating manned or unmanned submersibles. In general, towed sledges involve less sophisticated equipment because the needs for units for forward propulsion and for maintenance of a floating body at a specified distance above bottom are absent. However, sledges lack the manoeuvrability of submersibles, and are more likely to be fouled by obstructions on the sea-bed.

A 30-year study of the estuarine population of yellow eel, Anguilla anguilla, abundance in Bridgwater Bay, Somerset, UK, shows that the population number has collapsed. Since 1980, the decline has averaged 15% per year. The abundance of eel in 2009 is estimated at only 1% of that in 1980. This is one of the greatest systematically quantified crashes of a fish population ever reported. Collections of eels impinged on cooling water filter screens were made monthly at Hinkley Point power station between 1980 and 2010 and from Oldbury power station between 1996 and 1998. Eels are always present in the Severn Estuary, although there are large seasonal variations in abundance. At Oldbury, in the upper estuary, eels are least abundant in January. In contrast, in the outer estuary in Bridgwater Bay, eels are most abundant between November and March. The size-distribution of yellow eels ranged from <200 to >700 mm indicating an age-range since the glass eel stage of 2 to >25 years. The mean size-range has not changed since the 1980s indicating that the population collapse is not caused by a sudden recruitment failure. It is suggested that there has been a continual long-term failure of recruitment to compensate for losses. The reason for this is unidentified, but is unlikely to be changes in the North Atlantic Oscillation or other natural environmental variability. A major effort to improve eel survival to adulthood is required if this species is not to gently fade to extinction. This would likely involve a cessation of elver fishing, a reduction in the volume of estuarine water extracted for power station cooling and other purposes during which eels are entrained and killed, and the removal of obstructions which increase mortality during migration.

Little is known about the movements of male sperm whales, Physeter macrocephalus, in the North Atlantic. Recoveries of traditional harpoons and tags during commercial whaling indicated movements from Nova Scotia to Spain and from the Azores to Iceland and Spain. We compared collections of photo-identification images from different areas using the North Atlantic and Mediterranean Sperm Whale Catalogue and the Eurphlukes Phlex/Match programs. The largest collections of identified males (number of individuals, start and end date for data collection shown in parentheses) are for the Azores (297, 1987–2008), Andenes (375, 1988–1996 and 2008), Tromsø (84, 2005–2008). There were six matches between Andenes and Tromsø (~25 nm), with three of these re-sighted in multiple years and three photo-identification matches from the Azores to Norway (~2400 nm). In all cases individuals first photographed in the Azores (in 1993, 1999 and 2003) were matched to images collected later in Tromsø (in 2007 and 2008). In 1997 a photo-identification image from Andenes matched a male stranded on the west coast of Ireland. No matches were made to images in smaller collections from Iceland, Nova Scotia, Greenland, Dominica, Guadeloupe, Gulf of Mexico and the Mediterranean. These findings show the value of data collected from whale watching vessels and the importance of collaboration between groups to allow investigation on an ocean basin scale. It is hoped that with the coordinated collection of more images from around the Atlantic, further insight might be gained into the movements of these widely ranging animals.

Light is one of the most important abiotic factors influencing the (skeletal) growth of scleractinian corals. Light stimulates coral growth by the process of light-enhanced calcification, which is mediated by zooxanthellar photosynthesis. However, the quantity of light that is available for daily coral growth is not only determined by light intensity (i.e. irradiance), but also by photoperiod (i.e. the light duration time). Understanding and optimizing conditions for coral growth is essential for sustainable coral aquaculture. Therefore, in this study, the question was explored whether more light (i.e. more photons), presented either as irradiance or as light duration, would result in more growth. A series of nine genetically identical coral colonies of Galaxea fascicularis L. were cultured for a period of 18 weeks at different light duration times (8 hours 150 μE m−2 s−1:16 hours dark, 12 hours 150 μE m−2 s−1:12 hours dark, 16 hours 150 μE m−2 s−1:8 hours dark, 24 hours 150 μE m−2 s−1:0 hours dark) and different irradiance levels (8 hours 150 μE m−2 s−1:16 hours dark, 8 hours 225 μE m−2 s−1:16 hours dark and 8 hours 300 μE m−2 s−1:16 hours dark). Growth was determined every two weeks by measuring buoyant weight. Temperature, salinity and feeding levels were kept constant during the experiment. To detect possible acclimation of the corals to an increased light duration, rates of net photosynthesis and dark respiration were measured, hereby comparing coral colonies grown under an 8:16 hours light (150 μE m−2 s−1):dark cycle with corals grown under a 16:8 hours light (150 μE m−2 s−1):dark cycle. No increase in growth was detected with either increasing photoperiod or irradiance. Continuous lighting (24 hours 150 μE m−2 s−1:0 hours dark) resulted in immediate bleaching and the corals died after 14 weeks. Hourly photosynthetic rates were significantly reduced in the 16 hour light treatment compared to the 8 hour light treatment. As a result, daily net photosynthetic rates were not significantly different, which may explain the observed specific growth rates. Acclimation to photoperiod duration appeared neither to be mediated by changes in chlorophyll-a concentration nor zooxanthellae density. Based on the results of this study, we can conclude that the enhancing effect of light on coral growth is not only a matter of photons. Obviously, the availability of light was not limiting growth in these experiments and was probably in excess (i.e. stressful amounts). Other factors are discussed that play a role in determining growth rates and might explain our results.

The study of copepod assemblages indicated the presence of 22 species and 12 families in the southern coast of Sfax, 20 species and 13 families in the northern coast and 14 species and 8 families in the Ghannouch area, with a dominance of Oithonidae (79, 51 and 43% in the southern, northern and Ghannouch coasts, respectively). The relative abundance and the richness diversity of Oithonidae were found to be the most relevant indicators of anthropogenic pollution. Oithona nana, Euterpina acutifrons and Acartia clausi differed significantly in abundance between these three areas under differing degrees of pollution. The study of the structure, composition and density of the copepod fauna showed that the southern coast was a pollution-resistant ecosystem (H′ = 1.49 ± 0.33 bits ind−1; 22 species; density = 51.375 ± 4.340 × 103 ind m−3) followed by Ghannouch area (H′ = 1.74 ± 0.28 bits ind−1; 15 species; density = 11.979 ± 5.651 × 103 ind m−3) and the northern coast, considered as a restored area (H′ = 1.95 ± 0.26 bits ind−1; 21 species; density = 6.516 ± 4.304 × 103 ind m−3). The three ecosystems can thus be classified according to their degree of resistance to the anthropogenic inputs based on the results of the physico-chemical parameters and the species diversity as follows: southern coast > Ghannouch area > northern coast.

An undulating movement of the body was observed in Entobdella soleae, a monogenean found on the blind surface of a mud-dwelling flat-fish, Solea solea, at Plymouth. The movement is described and shown to have a breathing function, the rate of undulation increasing with decreasing oxygen content of the ambient sea water and vice versa.

The relationship between the movement and micro-habitat is discussed and the phenomenon is compared with breathing movements in other muddwelling animals.

A similar movement was noted in three other skin-parasitic monogeneans: Acanthocotyle sp. from Raia clavata, Pseudocotyle squatinae from Squatina squatina and Leptocotyle minor from Scyliorhinus canicula.

The effect of changes in particle size and sediment depth on byssal attachment was assessed in laboratory experiments. Mytilus edulis did not attach byssus pads to mud or silt less than 0·85 mm in diameter, but did attach pads to gravel. On gravel more pads were attached to the substrate (mean = 19·44 threads/mussel/week) than to other mussels in the group (mean = 7·34 threads/mussel/week). Because no byssal attachment to the finer substrates occurred and preference for other mussels in the groups rather than the plastic of the holding tank was shown, clumps, characteristic of mussel beds in the field, were formed. The clumps became increasingly well defined as the depth of the substrate increased. Few clumps were formed on the coarsest substrate as a result of preferential byssal attachment to gravel particles.

The main object of this paper has been to determine whether or no it is possible to differentiate the species and genera of Actinians by employing as criteria the characteristics of their nematocysts.

The species composition, abundance and vertical distribution of micronektonic cnidarians has been investigated in the upper 2800 m at Discovery Station 9969, located in the cold regime in the eastern Weddell Sea, Antarctica. In total 22 siphonophore and 20 medusan species were identified. Overall siphonophores were more abundant than medusae, but the latter usually contributed much more to the biovolume. On average, cnidarians contributed more than 50% to the total biovolume of each catch; and they contributed >70% to the combined total of all the samples. Despite the high water content of these animals, these large biovolumes meant that the cnidarians formed ∼25% of the total carbon in each catch. The possible impact of these gelatinous cnidarian populations on the ecosystem is discussed.

There are many Haliotis species which are widely distributed along the rocky coasts of temperate and tropical zones, most of them inhabiting the shallow sublittoral areas. Many of them form an important part of the fisheries industry in such countries as Japan, U.S.A., South Africa and Australia. In Guernsey, the Channel Islands, the ormer Haliotis tuberculata L. has been gathered as a local delicacy at low tide of good spring tides - locally known ‘ormering’.

Extensive tagging experiments have been undertaken at various places in the world for other species of haliotids, dealing with their growth and movement (Cox, 1962; Newman, 1966; Poore, 1972; Shepherd, 1973). For H. tuberculata, two tagging experiments, in which the growth and movement of sublittoral ormer populations were dealt with in detail, have been reported (Brehaut, 1958; Forster, 1967).

The present study has laid emphasis on the structure and growth of a shore population which has been the most important object of ormering to date.

In 1925 observations were carried out on two consecutive nights, June 17–18th and 18–19th, to study the diurnal changes occurring in the vertical distribution of certain marine plankton animals. Serial hauls were made with the stramin ring-trawl in the manner described in a previous publication (1). The series were so timed that they were made approximately in daylight, dusk, darkness, dawn and daylight on the two days in question. The actual details of the collecting, together with the fishing depths shown by the Admiralty depth recorder, are to be found in a previous paper on the behaviour of young fishes on the same occasion (2).

The colonization features of ciliate communities have proved to be a useful tool for indicating water quality status in aquatic ecosystems. To determine an optimal water depth for bioassessment using these ecological bioindicators, the colonization process of periphytic ciliates was studied at four depths of 1, 2, 3.5 and 5 m in Chinese coastal waters. Samples were collected at time intervals of 3, 7, 10, 14, 21 and 28 days using glass slides. The periphytic ciliate communities represented similar colonization dynamics from a depth of 1 to 3.5 m: (1) the temporal variability was well fitted to the MacArthur-Wilson and logistic models; (2) the species composition reached an equilibrium during the exposure time periods of 10–14 days; and (3) the maximum abundances were definitely higher at a depth of 1 m than those at 3.5 m. PERMANOVA test revealed that the colonization pattern at 1 m depth was significantly different from those at the other three depths. Results suggest that the colonization dynamics of periphytic ciliates may be influenced by water depth in coastal waters. These findings provide an important reference for establishing an optimal sampling strategy for bioassessment on large spatial/temporal scales in marine ecosystems.