The fine structure of the flagellar root system of Isochrysis galbana Parke (Prymnesiophyta) has been investigated and a reconstruction is presented. Associated with the left basal body and arising close to the base of the haptonema there is a root composed of a ribbon of approximately five microtubules running peripherally towards the ventral side of the cell. Near the basal body it is also associated with two additional bundles of microtubules which diverge from it and from each other passing deep into the cell.

On the right-hand side of the right basal body there is a root consisting of four microtubules (2+2) which runs peripherally in a dorsal direction. Another root, consisting of a single microtubule only, originates close to the distal connecting band between the basal bodies, and passes around the ventral side of the left basal body before following a course deep into the cell. In addition, several fibrous bands connect the bases of the flagella and haptonema. The general arrangement of the root system of 1. galbana is comparable with many other members of the Prymnesiophyta, but attention is drawn to a number of important differences, particularly between Isochrysis and some other members of the order Isochrysidales. The results are discussed in the context of the evolution, phylogeny and taxonomy of the Prymnesiophyta.

On the right-hand side of the right basal body there is a root consisting of four microtubules (2+2) which runs peripherally in a dorsal direction. Another root, consisting of a single microtubule only, originates close to the distal connecting band between the basal bodies, and passes around the ventral side of the left basal body before following a curse deep into the cell.

The first dorsal fin spines were used to estimate the age of juvenile bluefin tuna, Thunnus thynnus, from the Mediterranean Sea. Observations on the type of growth zones occurring on the outside margin of each spine section by month and marginal increment analysis indicated that only one translucent zone is formed per year between February and April, when lower sea surface temperatures are observed. Age estimations were based on counts of translucent zones on the spine sections and mean size at estimated age was calculated for the first three years of life.

Minke whale (Balaenoptera acutorostrata) distribution was derived from a 12 year observation programme in the Mingan Islands (Canada) and related to three geological features of the sea-floor: maximum depth, topography and geomorphology. Minke whale distribution was not uniform nor random in relation to maximum depth and topography, however, no evident trend was found. The most prominent factor was the presence of underwater sand dunes, where significantly more minke whales were observed than on any other bottom types. Because sand dunes are the favoured habitat of the minke whale major prey in the study area, an indirect link between minke whale distribution, geomorphology and substrate type is suggested.

Sampling at four salmon aquaculture sites along the west coast of Scotland has identified short-lived aggregations of planktonic hydrozoans (>280 individuals m−3), here termed blooms. Several such blooms were linked with increases in gill pathology and mortality in caged fish. Two types, Obelia sp. and Lizzia blondina, were found to cause blooms regularly and often concurrently. Species composition of hydrozoan populations and fluctuations in population sizes were spatially and temporally heterogeneous, with adjacent sites (within 30 km of one another and with similar oceanic exposure) experiencing no correlation between species composition and population density. Blooms appeared temperature-mediated, with all identified blooms by Obelia sp. and L. blondina taking place in water above 12 °C; however, temperature alone was not found to be predictive. Blooms were not significantly associated with change in salinity, water clarity, or photoperiod. Due to the apparent lack of broadly applicable predictors, we suggest that localized, targeted sampling and examination of planktonic hydrozoan populations is required to discern the presence or absence of a bloom. It is likely that many blooms have historically caused harm in salmon aquaculture while remaining unrecognized as the root cause.

Previous work has shown that three ecologically disinct morphs can be identified amongst beadlet anemones, Actinia equina L., ranging in column coloration from red to brown (Quicke, Donoghue & Brace, 1983; Quicke & Brace, 1984; Quicke et al. 1985). Each is adapted to a different inter-tidal range, and is characterized by a multi-locus gene complex, which includes loci encoding a number of metabolically important enzymes, pedal disc coloration and probably strength of pedal attachment. They have been named the upper (U), mid (M) and lower (L) shore morphs, and are relatively most abundant on the upper mid, lower mid and low shores respectively. Members of the U morph are typically homozygous slow and fast at a hexokinase locus and a malate dehydrogenase locus respectively, whereas those of the L morph are typically homozygous for the other allele at each of these loci; M morph individuals are heterozygous at both.

When sea water is stirred with mud and then filtered, its phosphate concentration may either increase or decrease. When the filtrate is ultrafiltered, the concentration increases.

Similar increases occur when the filtrate is stored in glassware, and these obscure any effects of the presence of colloidal material. On storage concentrations rise for about 2 hr., and then fall to as low as 2 mg./m.3 P2O5 in 18 hr.

Rise and fall are both prevented by the addition of formalin, chloroform or toluene, and are more noticeable in small containing vessels. Both occur during either day or night, and when temperatures are either rising or falling.

Until the spring of 1899 the true or common octopus (Octopus vulgaris, L.) had been comparatively rare in the neighbourhood of Plymouth during the past ten or twelve years—i.e. since the opening of the Plymouth Laboratory in 1888. Specimens could only be obtained for the aquarium at long intervals, in spite of the tempting inducements offered to fishermen. As much as ten shillings has more than once been given to fishermen for a specimen of this voracious mollusk. On the other hand, the smaller and less powerful octopod known as Eledone cirrosa was almost always obtainable, and the octopus tank in the aquarium was rarely devoid of several specimens.

In the early part of last year (1899) the situation began to change, and we were for the first time able to keep the tank supplied with a number of true octopus, since which date there has been no difficulty in procuring an unlimited number of specimens, either from the professional fishermen or in the ordinary course of our own fishing operations.

We noticed this increase in the abundance of octopus before there was any means of judging whether it was a purely local phenomenon, or was observable over a wider area. The first specimens were brought to us in January, and from May onwards they were obtained in increasing abundance. Early in the same year, however (though I have no exact record of the date), a visitor from the Channel Islands informed me that the increase of octopus in those islands was so great as to have already caused much damage to the shell fisheries there, since the octopus entered the pots of the fishermen, and destroyed the crabs and lobsters which had been caught.

The sizes, length and breadth, of the cyprids of Balanus balanoides, B. crenatus and Verruca stroemia have been measured on material collected. during the spring outburst and in the later part of the year.

The size-frequency curves for Balanus balanoides and B. crenatus show at least two distinct modesduring the spring, equivalent to populations of two distinct sizes. It is suggested that these correspond to populations developed in different environments. Measurements of the nauplii taken from adults at different points on the shore indicate that the size of the nauplii is dependent to some extent upon the conditions of development, the conditions also affecting growth and total nauplii output.

Swedish samples, in which the parents had developed under more uniform conditions, showed only a single population as regards size.

In B. crenatus and Verruca stroemia, which produce further broods during the year, the size decreases in these later broods. The rate of development of the eggs and embryos, probably dependent upon temperature, is suggested as the important factor.

Dinoflagellates (Dinophyceae) are considered to be one of the most abundant and diverse groups of phytoplankton; however, the viral impact on dinoflagellates was not studied until recently. This review shows the present information concerning the viruses infecting dinoflagellates and the ecology relationships between the host and the virus. So far, two viruses have been isolated and characterized: a large DNA virus (HcV: Heterocapsa circularisquama virus) and a small RNA virus (HcRNAV: H. circularisquama RNA virus); both of which are infectious to the harmful bloom-forming dinoflagellate H. circularisquama.

In the present review, we mainly discuss the relationship between HcRNAV and H. circularisquama from the viewpoint of physiology, ecology and genetics. It will help clarify the viral impact on dinoflagellate populations in marine environments to understand the host/parasite ecology.

Ontogenetic shifts in habitat use and diet are ubiquitous in nature and usually have profound consequences for the ecology and evolution of the species. In the case of species with strong interactions within their communities, such as keystone predators, understanding this kind of size-related change is critical to understand variation and connectivity among spatially distinct habitats of coastal communities. Yet the ecology of early life stages of marine benthic invertebrates, particularly asteroids, is poorly understood. Here we describe the results of surveys to characterize the habitat and quantify the abundance and diet of recruits of the sun star Heliaster helianthus, a keystone predator at rocky intertidal sites in central Chile. Our results support the existence of size-related, ontogenetic changes in habitat use and diet of this species. Recruits occupy boulders and crevices in the high or mid-high intertidal zones of wave-protected habitats and as they grow they move down towards lower tidal levels. Adults are characteristically found in the low intertidal zone of wave exposed and semi-exposed habitats. These changes in habitat use are accompanied by changes in diet composition and particularly by a broadening of the prey species incorporated in the diet. Since early stages of Heliaster appear to be most sensitive to predation and abiotic stress and since adults are such important predators in wave exposed rocky shores, knowledge of the basic ecology of early stages of this species is critical to fully understand the dynamics of intertidal communities.

The inshore fishery for the pilchard in Cornish waters has existed for several hundred years, and such records as are available concerning fluctuation in catches and market conditions have been reviewed by Couch (1865), Cushing (1957) and Culley (1971). Although pilchard have been landed from Lyme Bay, from the eastern half of the Channel, and from the southern North Sea (Couch, 1865; Furnestin, 1945; Cushing, 1957; personal communications G. T. Boalch) the catches have usually been incidental to other fisheries and more sporadic than in Cornish waters. Traditionally there are three areas fished for the Cornish pilchard: on the north-west coast around St Ives; in Mounts Bay and towards the Scillies; and between the Lizard Pt and Bolt Tail in Devon (Couch, 1865; Culley, 1971). The latter region, constituting the inshore waters of south-east Cornwall and south Devon, effectively forms the eastern limits of the regular occurrence of commercial shoals. Knowledge of the breeding and life-history of the fish in this region has always been scarce and subject to much hearsay evidence (reviewed in Southward, 1963). Up to quite recently it was thought that the main spawning area lay well to the west of the entrance to the Channel, and it was not until the investigations reported by Corbin (1947,195°) a nd Cushing (1957)tnat it was conclusively shown that extensive spawning can occur within the English Channel from May to October. The relationship of the spawning in the western Channel to the other areas of spawning off the entrance to the Channel and in the northern Bay of Biscay is illustrated in a recent series of reports (Arbault & Boutin, 1968; Arbault & Lacroix-Boutin, 1969; Arbault & Lacroix, 1971; Wallace, P. D. & Pleasants, C. A., duplicated ICES meeting paper CM 1972/J: 8), and is further demonstrated by Demir & Southward (1974) in discussing the results of a study of small scale seasonal changes in spawning intensity in inshore waters.

Abereiddy Quarry is shown in Plate I. It lies at 51° 56′N, 5°13′W (Ordnance Survey Reference SM 795315), 6 km northeast of St Davids in Pembrokeshire (Text fig. 1). The quarry, a disused slate working, is surrounded by high cliffs except to the west where there is a channel open to the sea. In 1902–3, operations ceased and the quarry began to fill with fresh water and sea spray. During 1932–3 the west wall was breached to allow access to the sea so that the basin could be used as a harbour. Abereiddy is now a deep, fully saline marine basin which, at low water, is 66 m across from north to south with a surface area of 0.356 ha and a maximum depth of 24 m. In this situation it has been possible to observe sublittoral rocky sea-bed communities in an extremely sheltered area through a summer thermocline and associated oxycline. Abereiddy Quarry has previously been investigated by Bailey, Nelson-Smith & Knight-Jones (1967), who published details of the vertical distribution of Spirorbis spp. The biology of serpulid worms in Abereiddy Quarry has been the subject of continuing investigations carried out from University College Swansea (E. W. Knight-Jones, personal communication).

The analyses reported here refer to water from International Hydrographic Station E I (lat. 50° 02′ N., long. 4° 22′ W.). They extend the sequence begun in 1923 when sufficiently sensitive chemical methods were first applied at this station (Atkins, 1923 a), and reported thereafter in a series of papers from this Laboratory (Atkins, 1923a, b, 1924, 1926a, b, 1928, 1930, 1953; Cooper, 1933a, b, 1937, 1938; Harvey, 1948, 1950; Armstrong, 1951; Armstrong & Harvey, 1950). This is a factual report and interpretation and comparison with earlier years are deferred.

Larval anisakid nematodes are among the most abundant helminth parasites of commercially exploited marine fish in the North-East Atlantic. Consequently, the biology of Anisakis and Phocanema in commercially sized fish from the North-East Atlantic has been quite extensively studied in recent years (see for example Davey, 1972; Rae, 1972; Young, 1972; Platt, 1975). There is, however, little available information on the occurrence of larval anisakids in small fish or species not used for human consumption. This is an important gap in our knowledge since information on the infection of such fish will increase our understanding of the circulation of these parasites within the marine environment and the levels of infection in commercial species.

Daily censuses of the hawksbill turtle Eretmochelys imbricata were taken during the nesting seasons 1995–2001 in three sandy beaches of the Yucatan Peninsula, Mexico (Celestun, El Cuyo and Isla Holbox), to evaluate aspects of its reproductive biology. A total of 9059 hawksbill turtle clutches was estimated for the study period. Nesting seasons began in mid-April and ended in early September, peaking in May–June. No significant differences were detected in the mean number of clutches per km among beaches. The largest number of clutches was observed in the supralittoral zone (6341: 70%), followed by the dune (2491: 27.5%) and the intertidal (227: 2.5%) zones. Variation in number of clutches showed a main peak in 1999, decreasing in 2000 and 2001. A significant decrease (3 cm) in body size of nesting females was detected between 1995 and 2001. Mean clutch size was 140 eggs/clutch, and a significant positive relationship between curved carapace length and mean clutch size was found at the three beaches. Incubation period, hatching success and emergence success varied between years (lowest values in 1998) and beaches (highest values at Isla Holbox), with no significant differences between the supralittoral and dune zones. Even though there was no evidence of a decreasing trend in nesting activity for the study period, the decrease in 2000–2001 suggests that additional beach monitoring is necessary to identify long-term trends, and to reduce potential losses of nests by human and natural causes in this globally important region for the hawksbill turtle.

Esperiopsis koltuni, a new species of the sponge family Esperiopsidae, is described from deep water of the Sea of Okhotsk. The new species has a unique growth form: there is a basal plate with radiating cylindrical branches, whose oval flat distal parts bear filament-like outgrowths. Megascleres are arranged differently in the main part of branches and in their distal flat parts. The dermal membrane contains isochelae with protruding alae and abundant sigmancistras. Microscleres are represented by large anchorate spatuliferous isochelae, small isochelae, sigmas and sigmancistras. Esperiopsis koltuni sp. nov. is hermaphroditic, with parenchymella larva. The larval skeleton consists only of sigmas and sigmancistras. Esperiopsis koltuni sp. nov. can be easily distinguished from other Esperiopsis species by dimensions and combination of spicule types. In particular, it is the only species in the genus with three different size categories of styles. The new species lacks the aquiferous system, has a characteristic body plan with symmetrical lateral expansions, an unusual arrangement of microscleres in the dermal membrane and true sigmancistras. Moreover, prey capture by a filament-like outgrowth of the flat distal part was observed. All of these characteristics indicate that Esperiopsis koltuni sp. nov. is a carnivorous sponge.

INTRODUCTION

Individuals of the Antarctic krill Euphausia superba Dana assemble in spring into dense formations (estimated 20,000 m3) which swim for long distances and at considerable speed (estimated 20 cm s−1) to search for patches of phytoplankton (Hamner, 1984). Recruitment to schools and maintenance of a defined position in a travelling formation, a remarkable social behaviour, requires some kind of communication system between individuals.

Vision, as a sophisticated image-processing system, habituating strongly with time, appears inappropriate for the task of continuously monitoring position in the formation. This is not in contradiction of the fact that the prominent eyes of Euphausia orient the shrimp with respect to the axis of light coming from above, and direct the photophores 180° away from light (Land, 1980). The function of the photophores is only partially explained (e.g. predator avoidance by counter-shading, Grinnell et al., 1988), their role in formation swimming being doubtful because they are reportedly active only during dawn and dusk. Of course the eyes help Euphausia to assemble in schools and to evade predators (Strand & Hamner, 1990) as well as fishing nets (Everson & Bone, 1986a,b), but a simple mechanical reflex seems more suitable to control individual position in the formation.

Specimens of the chemoautotrophic symbiont-bearing hydrothermal vent clam Calyptogena pacifica were collected from hydrothermal vents at the Endeavour segment of the Juan de Fuca Ridge. Total lipid was extracted from gill, foot and mantle tissues, and lipid class and fatty acid composition determined by thin layer chromatography with flame ionization detection (TLC–FID), gas chromatography (GC) and gas chromatography with mass spectrometry (GC–MS). An abundance of n–7 monounsaturated fatty acids (MUFA), especially in the gill, reflected the large contribution of chemoautotrophic symbiotic bacteria to the nutrition of this clam. The absence of n–8 MUFA suggests that C. pacifica does not contain methanotrophic symbiotic bacteria. Low levels of highly unsaturated fatty acids (HUFA) such as 20:5 n–3 and 22:6 n–3 were detected in C. pacifica and their presence is attributed to a source other than chemoautotrophic symbiotic bacteria. Significant levels of non-methylene interrupted dienoic fatty acids and eicosatrienoic acid (20:3) were also detected in C. pacifica and it is suggested that these fatty acids are synthesized from n–7 MUFA as alternatives to HUFA. In contrast to shallow water bivalves, elevated levels of triglyceride were detected in the gills compared to the mantle.

The harbour porpoise (Phocoena phocoena) is one of the common small cetaceans of European waters. This discreet and undemonstrative species is strongly represented throughout the cold waters of the northern hemisphere, and is the most abundant cetacean in the North Sea. In the last few years, some observations and studies indicate a shift of harbour porpoise distribution in European waters, from northern regions of the North Sea to the southern North Sea, English Channel and Celtic Sea. This shift may include a comeback around the coasts of France. Harbour porpoises inhabit shelf-waters and are often observed in shallow waters, conditions offered for instance by the coasts of Brittany in north-western France. We used opportunistic sightings, aerial survey and a ten-year strandings database to study the presence of harbour porpoises along the coasts of Brittany. Opportunistic sightings made by non-specialists did not confirm a strong presence of harbour porpoises along the Brittany coasts, most probably because of the undemonstrative behaviour of this cetacean. However, aerial survey and stranding analysis indicate that harbour porpoises have become natural inhabitants of the Brittany coasts once more: 68.6% of cetacean school sightings made during a 1578 km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100 km that peaked to 5.8 per 100 km to the top of the shallow waters of the south-western Western English Channel. The number of harbour porpoise strandings increased each year from 1997 to 2007, making a total of 135 along the coasts of Brittany. Other cetaceans did not show such an increase during the same period. Strandings of harbour porpoises were also characterized by an apparent increase as a proportion in relation to all the cetacean strandings during the months of September to January, by a marked impact of by-catch during winter, and by an almost total absence of stranded calves. The comeback of the harbour porpoise along Brittany coasts is clearly confirmed by our data, and a stable population seems to be established again along the coasts of Brittany. This tends to confirm the shift of the distribution of the species in certain European waters. Long term monitoring, diet and genetic studies are now planned for a better understanding of this shift, and for the effective implementation of a conservation plan.

The trophic behaviour, stomach contents, and morphology of the feeding appendages, with emphasis on setae, of a species of Laomediidae, Axianassa australis (Crustacea: Decapoda: Thalassinidea), were investigated. This species is a deposit feeder. The 32 described setal types were clustered in four main categories: plumed, serrate, plumodenticulate and simple. By examining the setae and spatial position of the segments of the appendages, it is possible to infer that the main function of the 1st and 2nd pereiopods, the 3rd pair of maxillipeds, as well as the dactylus, propodus, carpus and merus of the 2nd maxilliped, is to brush particles. The ischium, basis and coxa of the 2nd maxilliped appear to be specialized for particle retention. For the remaining mouthparts, brushing is generally the main function of the basal endites, while the coxal endites retain particles. Patterns of morphological adaptations to feeding habits are proposed for the Thalassinidea based on a review of the literature. Setal diversity, ratio of plumodenticulate to serrate setal types and mandible morphology are linked to ecological adaptations to trophic modes. Conversely, the presence and degree of development of the crista dentata appear to be related to phylogenetic heritage rather than to feeding mechanisms. Stomach contents are also indicative of trophic modes used by the species; while the predominance of small particles can indicate either filter or deposit feeding, stomach contents with high quantities of large particles suggest deposit feeding as the exclusive trophic mechanism.