The sand smelt (Atherina presbyter Cuvier) is a small, pelagic inshore fish common on some coasts of Britain. The biology of the sand smelt population in Southampton Water, Hants., U.K., has been described in detail (Turnpenny, Bamber & Henderson, 1981), but individuals less than 3 months old were not found during the course of that study.

The breeding cycle and growth of a population of Littorina littorea (L.)from an exposed rocky shore is compared with a population from a neighbouring sheltered estuarine habitat. The estuarine population matures earlier in the year, and maximum spawning activity is recorded in January compared with March on the open coast. This is considered to be the result of the higher nutritional status of the estuary. Egg capsules and veliger larvae have been found amongst the detritus on the estuary, and the establishment of an earlier settlement in this population is explained by concluding that a substantial proportion of the egg capsules do not leave the estuary, but undergo their full development in the moist detritus. At both localities individuals are sexually mature at a shell height of about 11–12 mm. Snails from the estuary reproduce for the first time during their second winter compared with the second or third winter for the open coast population.

Various indices related to reproduction and the fecundity of Helicolenus dactylopterus dactylopterus (Teleostei: Scorpaenidae) were analysed. Sexual dimorphism does not occur in the population we studied and the sex ratio is always equal. The size of the species at sexual maturity is a standard length of 130 mm for males and 145 mm for females. The maximum gonadosomatic index values for males and females are temporally out of phase to a large degree, which explains the intra-ovarian storage of spermatozoa that occurs in this species. There are large hepatic reserves which are basically used in the synthesis of vitellogenin, while the mesentery fat reserves are not mobilized until the end of the maturation process of the oocytes. Multiple spawning takes place between January and February, consisting of between 11,000 and 87,000 eggs, of about 500 μm in diameter. The fecundity of the species is, with a high degree of correlation, determined by the size and weight of the individuals.

In the Plymouth area there is often a marked and consistent difference in coloration of starfishes (Asterias rubens) from different populations. Starfish from populations to the south of Plymouth Breakwater are red-brown or occasionally pale yellow-brown in colour, whereas those from a population living well within Plymouth Sound have been found to be consistently bright red or brick red in colour (Vevers, 1949). In the present work analysis has been made of the integumentary carotenoids of dark red-brown A. rubens taken from the trawling grounds between Plymouth Breakwater and the Eddystone.

The effect of artisanal fishing on the abundance and diversity of coral reef fish assemblages was investigated in the Kisite Marine National Park and Mpunguti Marine National Reserve at Shimoni, Kenya. Fishing is prohibited within the Park whereas in the Reserve artisanal fishing using traditional methods is practised. Visual censuses of six representative reef fish families (Chaetodontidae, Lethrinidae, Lutjanidae and Serranidae in 1992 and 1994, and Labridae and Pomacentridae in 1994 only) were undertaken along 250×10 m band transects on two similar pairs of reefs subject to differing fishing pressure. The abundance of commercial species (Lethrinidae, Lutjanidae and Serranidae) was depressed in the Reserve. The unfished butterflyfishes (Chaetodontidae) and damselfishes (Pomacentridae) also showed a greater abundance in the Park than in the Reserve. However, neither species number nor Shannon diversity (H′) of any of these families was affected by fishing pressure. Possible reasons for these findings are discussed. The abundance of commercial species, though not of non-commercial unfished species, increased significantly in the Reserve between 1992 and 1994, suggesting that the unfished Park may be acting as a source of larvae or supply of emigrating adults for the depleted Reserve. The results are comparable with other recent studies describing the effects of fishing pressure and also with those studies detailing the effects of habitat refugia in coral reef areas.

Recoveries of tetracycline-labelled specimens of the sea urchin Echinus esculentus (Echinodermata: Echinoidea) from a wild population marked two years previously indicate very low skeletal growth rates in large adults. The post-tag growth in the test of a smaller specimen showed two clear growth zones in the middle layer of the plates, this conforming to the expectation of a single growth band each year. Merging of the spinochrome pigment bands present in the outer layer near the plate edge in older urchins will probably result in underestimation of age based on counts of these bands.

The large literature on growth banding in the European sea urchin Echinus esculentus L. and other echinoids is reviewed by Pearse & Pearse (1975), Smith (1980) and Gage (1991). Moore (1935) utilised spinochrome pigment banding in the genital (apical) plates of E. esculentus from the Isle of Man (Irish Sea) and Firth of Clyde (western Scotland) in one of the first studies utilising growth bands to interpret the age structure and growth rates of sea urchins. A single band was assumed to be formed each year. Counts of spinochrome bands have been used to obtain nearly all subsequently published age data for this species (Sime, 1982; Nichols et al., 1985; Sime & Cranmer, 1985; Comely & Ansell, 1988).

The present study was aimed at helping to resolve differing interpretations of age and growth rates in Echinus esculentus provided by these studies. This was undertaken by time marking the skeletal plates of a large sample of a wild population accessible by scuba diving on a submerged rock reef at 10–15 m depth off the islet of Eilean Mor near the Dunstaffnage Laboratory.

This is the first study to examine the seasonal biochemical composition of tissues from male and female Cucumaria frondosa. Gonad and body wall tissues were analysed for their protein, lipid, and glycogen content. Lipids were the single most abundant component in gonad tissues, followed by proteins and glycogen, for both males and females. However, only protein and glycogen in the gonad tissues differed between feeding and non-feeding periods as well as between pre- and post-spawning periods. Proteins and lipids were both more abundant than glycogen in the body wall tissues. In this case, only protein and glycogen were found to differ between spawning states. All differences observed in the gonad tissues were attributed to the annual reproductive cycle, which produces a need for nutrient storage to allow the production of gametes throughout the year. The body wall was thought to be responsible for the build up of reserves during the feeding period in order to support maintenance and reproduction during non-feeding months.

The commensal relationship between a snailfish, tentatively identified as Careproctus sp. (Osteichthyes: Liparidae), and the lithodid crab Paralomis formosa (Crustacea: Lithodidae) was photographed in situ using a baited camera vehicle, deployed at depths of 625-1525 m around Shag Rocks and South Georgia in the Southern Ocean. The series of time-lapse photographs taken clearly showed that the small liparid fish `hitched rides' on the crabs, presumably attaching to the dorsal carapace and legs of the crabs by means of their ventral sucking disk. Liparid fish of 20-90 mm total length, corresponding to juveniles and adult sizes, were observed on the crabs and indicate that Careproctus sp. is closely associated with P. formosa for the whole of the life cycle of the fish. Such an association may provide the snailfish with protection from potential predators as well as a means of transport towards food-falls but at no apparent cost to the crabs.

Naturally spawned bass, Dicentrarchus labrax, eggs were incubated from fertilization at 15 temperatures from 6·8–20·6°C, and the developmental process was categorised into seven stages. Times from fertilization to the midpoints of each stage were calculated at each temperature. Knowledge of the developmental stage and incubation temperature was used to derive predictive relationships with which to age eggs. Minimum precision of age prediction was ±18 h. The first developmental stage was divided into six substages, and temperature-stage relationships derived to improve the precision of ageing to a minimum of ±1·75 h during early development. Bass eggs failed to hatch at temperatures below 9·7°C and above 16·8°C; this observation is discussed with reference to the developmental process.

The hypothesis of a locomotor role for the free rays of Trigloporus lastoviza is supported by: (1) their periodic retraction and protraction during slow displacement over the substratum whenever the propulsive body wave responsible for swimming is not visible; (2) the integration of the rays' individual cycles into a hexapod gait apparently generated by a metachronal impulse; and (3) the kinematic features of the longest free ray in relation to the bottom-walking velocity.

The spectral composition of the light of four species of polynoid worms has been measured, viz. Harmothoë longisetis, Gattyana cirrosa, Polynoë scolopendrina and Lagisca extenuata. The method involved the use of coloured spectral filters and two multiplier phototubes. The spectral emission curves of the four species are similar. They are asymmetrical in shape, prolonged towards longer wavelengths, with maxima at about 515 mμ (510–520 mμ.). Values for luminous efficiency are calculated (ratio of luminous flux to radiant flux); for human scotopic vision (λmax at 505 mμ), efficiency is 61%.

Recent studies have shown that anguillid eel populations in habitats spanning the marine–freshwater ecotone can display extreme plasticity in the range of catadromy expressed by individual fish. The apparent use of marine and freshwater habitats by the European eel Anguilla anguilla was examined by analysing the strontium (Sr) and calcium (Ca) concentrations in otoliths of eels collected from a tidal Atlantic lake system in Ireland. Variations of the Sr:Ca ratio in the otoliths indicated that a variety of environmental salinities had been experienced in the habitats that were occupied during the growth phase of these individuals in the tidal Atlantic lake system. The otolith microchemistry of these eels indicated that most of the eels had entered each salinity environment (freshwater (FW); brackish water (BW); marine-dominated water (MW) and full seawater (SW)) from fresh water to full seawater just after recruitment and had stayed in each environment until maturation without movement to other salinity environments. Only 2 of 93 (2%) eels had shifted their habitat once in their lives. This result suggests that each individual might have an environmental habitat preference, although each individual could move along a short (<2 km) salinity gradient.

The ciliates are considered to be the dominant protozoan group in the lacunar system of marine sediments and the important role which they play in the benthic ecosystem has been emphasized (Fenchel, 1969). More than 7500 ciliate species have been described (Corliss, 1974 a) and their distribution is worldwide (Agamaliev, 1967 a; Burkovsky, 1970c; Dragesco, 1960, 1965a; Kahl, 1930–35; Petran, 1967; Raikov, 1962). However, only two surveys of the interstitial ciliates of the British Isles have been carried out (El Maghraby & Perkins, 1956; Lackey & Lackey, 1963). This paper describes a study of the systematics and ecology of interstitial ciliates of the North Yorkshire coast.

Microzooplankton community composition, abundance, biomass and grazing impact were assessed, along with measurements of ciliate growth and mortality, during the onset of the spring bloom in the north-east Atlantic. The study was undertaken as part of the UK Biogeochemical Ocean Flux Study during 1 May to 15 June 1990. The microzooplankton community was composed of protozoans and metazoan developmental stages with respective mixed-layer depth integrated biomass values ranging from 127 to 638 and 74 to 394 mg C m−2. High numbers of aloricate ciliates (up to 35,000 cells l−1) dominated the microzooplankton community during early May prior to the onset of the spring bloom. Ciliate abundance then declined rapidly during mid-May with community growth rates ranging from −0·71 to 0·23 d−1. High abundances of metazoplankton (up to 400 l−1) were also recorded at this time and may have contributed to the decline in ciliate numbers. In late May and early June the protozoan community comprised a more even mix of dinoflagellates, tintinnids and aloricate ciliates. Phytoplankton mortality rates, measured using a dilution technique, ranged from 0·2 to 0·5 d−1. The microzooplankton consumed 8 to 44 μg C l−1 d−1, equivalent to between 16 and 40% of the chlorophyll biomass and 38 and 154% of primary production. These high rates of herbivory reflect the predominance of small (<5 μm in length) phytoplankton cells present throughout the first half of the study and support previous studies demonstrating the microzooplankton to be the main grazers of phytoplankton in the north-east Atlantic. However, there is also evidence that a disparity between predator and prey may have prevented a response by the microzooplankton to rapid increases in phytoplankton biomass and production during the spring bloom.

Since the first visual observations of hydrothermal vents in the Eastern Pacific in 1976 (Lonsdale, 1977) these areas of the sea bed have been characterized by their spectacular, and in most cases, novel fauna. Of the 236 macrofaunal species described from hydro-thermal vents, 223 were new to science according to the most recent estimate (Tunniclif f e, 1991), although there are many species still awaiting description. The vent areas are characterized not only by the organisms present but by those which are apparently absent. Absentees include sponges, brachiopods, bryozoans, echiurans and echinoderms, although the last phylum is represented by occasional sightings of echinoids, ophiuroids and holothurians (Grassle, 1986; Tunnicliffe, 1991; Segonzac, 1992).

The composition and structure of a molluscan assemblage inhabiting an outcrop with a coralligenous community was studied in southern Spain. A total of 117 molluscan species were identified, with gastropods as the dominant group. Calyptraea chinensis was the dominant species and the family Conidae presented the highest number of species. The Shannon–Wiener diversity index and the Evenness showed non-significant changes between cold and warm months, displaying high values (~4 bits and ~0.8 bits respectively). Some of the dominant and/or frequent species are strictly associated with coralligenous-building organisms, such as Neosimnia spelta with gorgonians. Regarding trophic guilds, carnivores are the dominant group, followed by filter feeders due to the high abundance of C. chinensis. Regarding biogeographical distributions, most of these species (<95%) are widely distributed in European waters, the number of strictly Mediterranean species being very low. The Alboran Sea represents the distributional limit towards the Mediterranean for some species found in this bottom, such as the Atlantic Bela powisiana. Rocky–coralligenous bottoms are scarce in the western Alboran Sea but support a high species richness molluscan assemblage, displaying higher diversity values than the surrounding soft bottoms and increasing the biodiversity at local scale. This high biodiversity is partly explained by the coexistence of different taxa with contrasting biogeographical affinities promoted by the geographical location of the area. Due to this, conservation efforts should be required to protect this stretch of coastline where one of the most biodiverse invertebrate assemblages along the European coasts can be found.

Virus-like particles (VLPs) were observed in thin sections of the plumose anemone, Metridium senile, collected from seawater off the west coast of Sweden in 1969. The VLPs were observed in the nucleus of spiroblasts and amoebocytes; they were either pentagonal or hexagonal in section, indicating an icosahedral structure. Virus-like particles were ∼60 nm in diameter, with an electron-dense core 40 nm in width; they had no apparent tail. This is the first substantial report of viruses observed in sea anemone cells.

Previous studies identified the Amazon river dolphin (Inia geoffrensis) as the species frequently traded in public markets of Pará and Amazonas State (Brazil). In order to investigate the geographic origin and the taxonomic identification of these specimens we analysed 21 samples provided by residents of the city of Belém and vicinities (Pará State, Brazil), presumably purchased in the ‘Ver-o-Peso’ Market (Belém) or the Manaus Municipal Market. DNA was extracted from dehydrated genitalia or from genitalia conserved in alcohol and the cytochrome b gene was PCR-amplified. Phylogenetic analyses showed identical topologies in both MP and NJ trees, with Sotalia splitting into two groups, one clade comprising the estuarine dolphin (S. guianensis) and all eight haplotypes from market-samples and another one, comprising the tucuxi (S. fluviatilis) haplotypes from the GenBank. Our findings indicated that the marine species is under a stronger commercial pressure than the Amazonian river dolphin (I. geoffrensis) and the tucuxi (S. fluviatilis) in the region. Therefore population dynamic studies as well as population monitoring should be carried out in order to evaluate the effects of this commercial hunting on the species and its local populations. The marine dolphins have been incidentally captured in gill-nets in the region, suggesting that these activities must also be monitored at the same time that social programmes must be implemented in order to inform and clarify local community and people involved in fishery activity to avoid that more animals might be captured and killed.

The pink shrimp (Farfantepenaeus paulensis) is a very important fishery resource in southern/south Brazil. A great part of the total capture at these regions results from the artisanal fishery activity in Patos Lagoon estuary. The study of this species has importance because it is the main source of income for the communities of artisanal fisheries. This paper relates the climatic effects and the size of the species' adult stock with the harvest of pink shrimp in the estuary, in order to determine the influence of these variables on annual landings (t).