In most fishes the fibre types of the axial muscles (musculus lateralis) are organized in separate groups. Commonly, there is an outer layer of red fibres of small diameter, medially there is a layer of larger, white fibres. With some modifications this scheme holds for the hagfish (Flood & Mathisen, 1962; Korneliussen & Nicolaysen, 1973), for sharks (Bone, 1966; Hagiwara & Takahashi, 1967; Brotchi, 1969) and for teleosts (e.g. Nishihara, 19673 Rayner & Keenan, 1967; Walker, 1971; Nag & Nursall, 1972; Patterson & Goldspink, 1972). The tail muscles of salamanders are similarly arranged (Sherkov, 1970; Totland, 1976 a, b).

Oikopleura dioica is the only recorded appendicularian in the Black Sea. During the last two decades major changes in the O. dioica population size as well as total zooplankton community structures were recorded when invasive ctenophore species appeared in the Black Sea ecosystem. The state of the O. dioica population, before the invasion of ctenophores Mnemiopsis leidyi and Beroe ovata, is reviewed. The effect of the invasion of these ctenophores on the total zooplankton and particularly on the O. dioica standing stock is summarized from our long-term data and published information. The abundance, biomass and species composition of zooplankton greatly decreased after the ctenophore Mnemiopsis leidyi invasion due to predation by M. leidyi. Specifically, the abundance of O. dioica declined at that period. But with increasing numbers of a new invader, the ctenophore Beroe ovata, a predator of M. leidyi, in 1999, the zooplankton community began to recover. The population density of Oikopleura dioica also gradually increased to a level that was within the range of its abundance before the M. leidyi outbreak and even higher due to increasing its prey bacteria, which was provoked by the mucus released by B. ovata.

Members of the small suborder Runcinacea have recently been reviewed and efforts have been made to group new findings (Burn, 1963; Baba, 1967; Miller & Rudman, 1968). The following structures served for the classification: gills alone (Baba, 1967), gills, radula, gizzard-plates and shell (Burn, 1963). According to this classification a more detailed subdivision became necessary. Two proposals brought forward by Burn (1963) and Baba (1967) are in discussion (see below). Two new genera Runnica and Pseudoilbia (Miller & Rudman, 1968) have not as yet been definitely placed in a family. As a consequence of this grouping some of the former members of the genus Runcina have been moved to another genus, e.g. Runcina elioti (Baba, 1937) to Runcinida (Burn, 1963) by reason of four or five gills surrounding the anus in a semi-circle, and Runcina setoensis (Baba, 1954; Ghiselin, 1963) to Metaruncina setoensis (Baba, 1967) because of its single gill and a greatly reduced radula (compare Table 1).

The parasitic astomatous holotrich ciliate, Orchitophrya stellarum Cépède, has been found in the testes of starfishes (Asterias rubens) in the Plymouth area. It was found only in starfishes from numerically rich and well-fed populations, which also showed large gonad growth. In such populations it occurred in up to 28% of the males during March-April 1947, and in lower percentages during the spring of the three following years. The parasite was never found in a geographically adjacent population containing smaller numbers of poorly fed starfishes. The parasite was found to be relatively more common in the testes of medium-sized starfishes than in those of large and small starfishes.

Presence of the parasite causes a complete breakdown of all the germinal tissue of the testes, so that most of the infected starfishes suffer complete castration. This involution of the testicular tissue has been studied, and photomicrographs are given which show a number of stages in the process.

An increasing number of cryptic species are being discovered within sponges with assumed wide geographical distribution. Pachymatisma johnstonia (Bowerbank in Johnston, 1842) (Astrophorida: Geodiidae) is one of the most common and known sponges throughout the north-east Atlantic coasts. Pachymatisma normani Sollas, 1888 is a northern species previously synonymized with P. johnstonia by Topsent. It is here redescribed on the basis of fresh material from the type locality, the Korsfjord in the Bergen area (Norway). Spicules are shown to be reliable characters to distinguish the species investigated. Pachymatisma normani is characterized by larger spicules, most markedly in the sterrasters. Our observations also suggest that habitat and gross morphology distinguish P. johnstonia from P. normani. Furthermore, using a partial sequence of the cytochrome c oxidase subunit I (COI) and an ITS1-5.8-ITS2 nuclear fragment, we show that consistent genetic differences exist between the two species. A brief overview of the genus and a key to the known species are also given.

A study of the polychaetes living on isolated seamounts was undertaken to give data on marine biogeography and the dispersal of marine invertebrates. The data from the Meteor and Josephine seamounts came from Hartmann-Schröder and Rosenfeldt's work in the 1980s. Data from Hyeres came from Bellan's work in the 1960s, and data from the Atlantis and Hyeres seamounts were obtained during the Seamount 2 French expedition on board the ‘Suroît’ in 1993. Thirty-five sites from 280 to 2205 m were sampled: 16 on Atlantis (13 with polychaetes), and 19 on Hyeres (16 with polychaetes). In all 84 polychaete taxa from four seamounts were studied: Atlantis, 36; Hyeres, 33; Josephine, 34; and Meteor 50, but data analysis was based on the following number of taxa: Atlantis, 31; Hyeres, 29; Josephine, 34, and Meteor 48. Two groups of sites were identified by cluster analysis: I, Atlantis and Hyeres; and II, Josephine and Meteor. Only seven species were present at all sites. Nine families were present only in group I and six other families only in group II. Hesionidae (three species) occurred in group I, conversely Syllidae (16 species) were sampled only in group II. Some of the species were cosmopolitan (31%), 49% had a large distribution in the Atlantic, 11% were lusitano–mauretanian species, and only 6% were endemic; 51% of the species have direct development against 46% of the species which had a planktotrophic development and 3% a lecithotrophic development. Results of the biogeographical distribution and reproductive patterns of the polychaetes collected on these four sites were compared.

The spiny dogfish Squalus acanthias is widely distributed in Atlanto-Mediterranean regions, being captured off the Languedocian coast (southern France, northern Mediterranean), despite a decline of landings. The male and female sexually matured between 635–700 mm and 860–880 mm total length (TL), respectively. The largest male and female were 800 mm and 1110 mm TL, respectively and weighed 2220 g and 8900 g, respectively. There was a significant relationship for total mass versus TL, and liver mass versus TL between males and females. The diameter of the largest yolky oocytes ranged between 43 and 47 mm (mean 45.08 ± 0.98), while the mass ranged between 29.5 and 37.4 g (mean 31.79 ± 2.20). Near- term embryos ranged from 245 to 271 mm TL (mean: 258.85 ± 7.28) and weighed from 47.5 to 55.9 g (mean 53.35 ± 2.26). Ovarian fecundity ranged from 6 to 15 (mean = 10.38 ± 2.66). Uterine fecundity or litter size ranged from 4 to 12 (mean = 8.15 ± 2.07). Both fecundities showed a positive relationship with TL of females. A chemical balance of development based on mean dry masses of yolky oocytes and near-term embryos was 0.87 and suggested that S. acanthias is a pure lecithotrophic species. Hepatosomatic index (HSI) and gonadosomatic index (GSI) significantly increased with size in both males and females. HSI reached the highest values in both sub-adult and adult specimens, reflecting the role of the liver in the gonadal production as well as in buoyancy, while in the GSI the highest values were observed in pregnant females. Vitellogenesis proceeds in parallel with embryonic development. Near-term females were captured in different months of the year while a short period of resting could not be excluded between parturition and the beginning of a new pregnancy, so it appears difficult to delineate the length of gestation. However, a reproductive cycle with a wide range from 18 to 24 months remains a suitable hypothesis.

This is the first report on the Zoantharia fauna (Cnidaria: Hexacorallia) of the isolated oceanic island of Ascension, southern Atlantic, where zoantharians are a dominant component of the shallow-water benthos. Specimens from two expeditions (1983, 2012) were examined regarding external morphology and molecular phylogeny using three DNA markers, which confirmed the presence of four zoantharian species: Palythoa caribaeorum; Palythoa aff. clavata; Parazoanthus swiftii; and Zoanthus sp. Two of these, Palythoa aff. clavata and Parazoanthus swiftii, were previously only known from the western Atlantic and Caribbean. Molecular examination of the zooxanthellae (=Symbiodinium spp.) of Palythoa specimens showed that they were in association with only one type, subclade C1.

Knowledge about the diet of fish-eating predators is critical when evaluating conflicts with the fishing industry. Numerous primary studies have examined the diet of grey seals Halichoerus grypus and common seals Phoca vitulina in a bid to understand the ecology of these predators. However, studies of large-scale spatial and temporal variation in seal diet are limited. Therefore this review combines the results of seal diet studies published between 1980 and 2000 to examine how seal diet varies at a range of spatial and temporal scales. Our results revealed extensive spatial variation in gadiform, perciform and flatfish consumption, likely reflecting variation in prey availability. Flatfish and gadiform consumption varied between years, reflecting changes in fish assemblages as a consequence of factors such as varying fishing pressures, climate change and natural fluctuations in populations. Perciform and gadiform consumption varied seasonally: in addition there was a significant interaction between season and seal species, indicating that grey and common seals exhibited different patterns of seasonal variation in their consumption of Perciformes and Gadiformes. Multivariate analysis of grey seal diet revealed spatial variation at a much smaller scale, with different species dominating the diet in different areas. The existence of spatial and temporal variation in seal diet emphasizes that future assessments of the impact of seal populations should not be based on past or localized estimates of diet and highlights the need for up-to-date, site specific estimates of diet composition in the context of understanding and resolving seal/fisheries conflict.

A dichotomous identification key for brachyuran zoeal stages from Peter the Great Bay (Russian waters of the Sea of Japan) is provided for the first time. The key covers 16 taxa identified to species level and uses only the most conspicuous external characters of larvae that are easy to observe under a stereomicroscope without specimens dissection. The key is based on the accounts by various authors and new original descriptions of larvae obtained both from plankton samples and from laboratory culture. Brief descriptions of larvae of 16 brachyuran species are also included.

Research into the feeding habits of cetaceans has traditionally relied on examining samples taken from the digestive tracts of commercially caught or stranded and by-caught animals. This depends on the identification and measurement of hard parts such as fish otoliths. Otoliths are often partially digested in the stomach, making quantitative estimates of fish size from otolith size biased.

As a preliminary attempt to quantify the size reduction of otoliths found in the stomachs of small cetaceans, an in vitro digestion experiment was carried out. Otoliths of herring, whiting, poor cod and haddock were digested at 37°C, pH=3·6, and measured every 60 min.

Linear regressions relating otolith size to digestion time and original size generally provided an adequate description of the time course of size reduction. The parameter that changed most rapidly due to digestion was otolith thickness. Differences in digestion rates between species reflect the general robustness and shape of the otoliths.

A simulation using actual dietary data showed that the overall diet composition was not radically changed by accounting for otolith digestion, although the apparent contribution of herring increased as the assumed digestion time is increased, because herring otoliths were the most susceptible to digestion.

Weight–Body Length relationships (WLR) of 45 fish species (37 Actinopterygii and eight Elasmobranchii) were investigated. A total of 31,167 individuals were caught and their biological parameters measured during the four quarters from 2013 to 2015, on five scientific surveys sampling the North-eastern Atlantic Ocean from the North Sea to the Bay of Biscay (ICES Divisions IVb, IVc, VIId, VIIe, VIIg, VIIh, VIIj, VIIIa and VIIIb). Among 45 tested species, all showed a significant correlation between total length (L) and total weight (W). The influence of sex on WLR was estimated for 39 species and presented a significant sexual dimorphism for 18 species. Condition factor (K) of females was always higher than for males. Moreover, a spatial effect on the WLR according to five ecoregions (the Bay of Biscay, the Celtic Sea, the Western English Channel, the Eastern English Channel and the North Sea), was significant for 18 species among 38 tested species. The temporal effect was tested according to components (year and quarter/season). The seasonality effect on WLR is more frequently significant than the year especially for the Elasmobranchii species, and can be related to the spawning season. Finally, depressiform species (skates, sharks and flatfish) are characterized by positive allometric growth, whereas there is no such clear pattern regarding roundfishes growth, whatever their body shape is.

The stomach contents of juvenile Magellanic penguins, Spheniscus magellanicus, stranded along the Atlantic coast (21–23°S) during the extreme mortality event of 2008 were analysed. The isotopic profiles of this species and their prey in a wintering area are presented to identify trophic relationships and to evaluate whether the prey species recovered in the stomach contents were assimilated. The prey groups recorded were molluscs (cephalopods and gastropods), teleost fish, and, to a lesser extent, crustaceans (decapods and isopods). Cephalopods were the most representative prey, and Argonauta nodosa was the most abundant species. Plant remains and solid waste were atypical items found in the stomach contents. The nitrogen isotope (δ15N) values found in this study confirm the higher trophic position of the penguins (14.5‰) relative to their prey (11.7–12.3‰). The carbon isotope (δ13C) measurements of all species are characteristic of marine coastal environments (−18.7 to −16.8‰). A Bayesian approach applied to stable isotope mixing models showed that cephalopods are assimilated to a greater extent than fish. However, the poor nutritional condition of specimens that reach the Brazilian coast, especially at the northern limit of migration (~21°S), indicates that prey ingestion is not sufficient for the maintenance of body weight.

Basking shark (Cetorhinus maximus) movement patterns and growth rates over annual cycles remain entirely unknown. Here the re-sighting of a female identified by a highly distinctive first dorsal fin, after a 3·1 year period is described. Our results show this individual foraged at the surface in coastal areas off south-west England in at least two of four summer seasons and increased in total length by 2·4 m over this period. The growth increment observed was similar to that predicted from the growth model for this species.

The disposal of wastes to sea is regulated internationally by the Oslo and Paris Conventions, which were ratified by the United Kingdom in 1975 and 1978 respectively. Under these Conventions the direct disposal of certain substances, for example mercury and cadmium compounds, is prohibited, unless they are present in wastes as trace constituents. Of particular concern in the case of mercury is its possible incorporation in the aquatic food chain and transfer to man via marine foodstuffs. There are many examples of accumulation of mercury by fish in contaminated areas e.g. Liverpool Bay (Norton & Murray, 1983; Franklin, 1987); Haifa Bay (Hornung & Krumgalz, 1984); Minimata Bay (Fujiki, 1980) and in river systems such as the Ems (Essink, 1980,1988).

Lough Hyne was Europe's first Marine Nature Reserve and is a well known biodiversity hotspot that supports extensive sponge assemblages. The unusual, but predictable, flow and sedimentation regimes have important impacts on the sponge assemblages at the species and assemblage levels. Here I present a review of recent sponge research at Lough Hyne, which covers: (1) a description of the sponge-dominated habitats; (2) the biological and physical factors controlling sponge biodiversity and abundance; (3) sponge species and assemblage level morphological variability; and (4) the relationship between sponge morphological, species and functional diversity. It appears that physical factors are primarily responsible for the sponge diversity and abundance patterns found in Lough Hyne, although the importance of intra- and interphyletic (particularly with algae) competitive interactions requires further investigation. Although our knowledge of how sponges respond and adapt to environmental variability has increased substantially because of the research conducted at Lough Hyne, I have highlighted a number of future research areas in the context of Lough Hyne sponge assemblages, which are relevant to understanding structuring processes across the globe.

(1) In general, the changes in pH were similar to those observed in previous years. On six occasions the pH at the surface at Station L4 was lower than at the bottom.

(2) The changes in carbon dioxide in the spring agree with the conclusion, formed in Part I from nutrient salt data, that the early start in plant production in mid-Channel was not maintained and that by the middle of April production had become much greater nearer the shore.

(3) The partial pressure of CO2 during nine months out of twelve has been observed to be lower than that of the atmosphere and equal or slightly higher during the remaining three months.

(4) It is suggested that the fall in (Total CO2+O2) during the course of the summer was due mostly to loss of oxygen to the atmosphere. After allowing for carbon dioxide possibly removed from the sea as calcium carbonate and for the loss of oxygen due solely to rising temperature of the water, a net loss of 110 litres of oxygen was found from a column 1 sq. metre in cross-section and 70 metres deep; or 9 cubic kilometres from the whole of the Channel. If this is regarded as a closed system, the oxygen must have been formed during photosynthesis from an equal volume of CO2 dissolved from the atmosphere. But the required transfer of CO2 across the surface of the sea is too great to be accounted for by existing data on the rate of invasion of CO2 into sea-water as calculated for a small bubble of gas in water.

(5) Estimates of the phytoplankton crop have been made, based on the seasonal consumption of carbon dioxide, of phosphate and of nitrate and on the oxygen lost to the atmosphere. All four are of the order of 1,400 metric tons wet weight per sq. km. of surface, in close agreement with the figure calculated by Atkins. The crop production calculated from consumption of silicate is less than one-tenth of this. This is attributed not only to the presence of planktonic organisms requiring no silica but to the silicate being used several times over in the course of the season.

(6) About 0·06% of the wet weight of phytoplankton produced is harvested as fish.

(7) A small variation in excess base, equivalent to about 0-1% of the total calcium present, has been detected between the surface and bottom in summer. The result requires confirmation.

Six species of geophilomorph centipede are reported from the littoral zone in the Plymouth area, and in two cases, where they differ from previous descriptions, the significance of these differences is discussed. It is suggested that the various British and French populations of Geophilus algarum and Geophilus fucorum may be subspecies of one polytypic species.

It is shown that Strigamia maritima and Hydroschendyla submarina differ in the way in which they have adapted to life on the shore. The former lays permeable eggs and migrates out of the littoral zone to lay them and to moult, the latter lays impermeable eggs and moults in the intertidal zone. Information on the prey of S. maritima at Plymouth is given.

The variations between some populations of littoral centipedes is discussed and possible reasons for the high density of populations of S. maritima and H. submarina are given.

The cirrate octopod family Stauroteuthidae is revised on the basis of new material collected from the North and South Atlantic and a thorough examination of relevant type material. The family is characterized by the presence of a secondary web, U-shaped shell vestige, reduced mantle aperture and with long cirri, not reaching the arm tips. The radula is absent. The family contains a single genus with two valid species, Stauroteuthis syrtensis and S. gilchristi, which are redescribed based on the holotypes and new material. Chunioteuthis ebersbachii is a junior synonym of S. syrtensis and C. gilchristi is placed in the genus Stauroteuthis. The genus Chunioteuthis is no longer valid. The form and arrangement of suckers distinguish the two species of Stauroteuthis. Stauroteuthis syrtensis is broadly distributed in the North Atlantic at depths of 700—4000 m with peak abundance at 1500—2500 m. Stauroteuthis gilchristi is known only from the type locality off Cape Town (2604 m) and from new material captured off South Georgia (1000 m).

The importance of bacterial action in the seas has long been recognised, but investigation in marine bacteriology lags behind that of corresponding terrestrial problems. Such general information about marine bacteria as is now available is derived mainly from bacteriological work of some decades ago. At that time the technique of the science was not fully developed, but at the present day it has become so specialised that it lies outside the province of the marine biologist, although he alone is able to appreciate the significance of bacteria in the general economy of the sea.