The silver roughy, Hoplostethus mediterraneus is a benthopelagic cosmopolitan fish regularly caught as by-catch of the deep-water crustacean trawl fishery (CTF) in the central–eastern Mediterranean. Monthly samples of silver roughy were sampled from the catches of four commercial trawlers in 2004. Each trawler operated in different fishing grounds (FGs), located off Northern Tunisia, South of Sicily, Malta Islands and in South Levant, for which different exploitation levels are reported. The overall length–frequency distribution (LFD) was constructed, and fishing impact indices (length as percentage of LFD, optimum and maximum length, percentage of mega-spawners and total mortality/von Bertalanffy curvature ratio) were calculated. In spite of an overall acceptable status (juveniles, matures and mega-spawners were present in the catch), sampling data revealed significant differences in LFD shape and status indices between FGs. Those FGs traditionally considered more exploited (Northern Tunisia and South of Sicily) showed a dominance of juveniles, a rarefaction of mega-spawners, a reduction in maximum and asymptotic length and a higher Z/K ratio. Considering the general homogeneity of Mediterranean deep-water habitats, the pelagic dispersal of eggs and the poor swimming capabilities of silver roughy, the present results indicated that deep-water trawling may induce a slow and subtle, although significant, erosion of the older, late maturing and slow growing component of the stocks in the Mediterranean (so-called longevity-overfishing).

Gut residence time (GRT) is often reported to be extremely variable among crustaceans. In this study, GRT was measured in tethered mysids that were fed continuously, and appearance of the first faecal pellet was found to be quite consistent averaging 1.6 h. There was no significant difference between GRT in those mysids held singly and those accompanied by free-swimming conspecifics, even though previous studies have shown metabolic benefits in social behaviour. Gut residence time data from a range of pelagic crustaceans feeding continuously showed a clear linear relationship with size. It appears that, when feeding ceases and crustaceans are allowed to clear their guts in filtered water, GRT can be very long and variable. However, when feeding is continuous, GRT can be relatively short and consistent.

Ten species of deep-water Pycnogonida are recorded, mainly from the north-eastern Atlantic Basin. Of particular interest are Ascorhynchus abyssi Sars (new to the British Isles), Colossendeis arcuata A. Milne Edwards (northernmost record in European waters), C. bicinc0ta Schimkewitsch (third Atlantic record, depth range increased), C. macerrima Wilson (new records from the English Channel), Nymphon laterospinum Stock (new to the Indian Ocean), Pallenopsis (Bathypallenopsis) oscitans (Hoek) (new to the English Channel and bathymetrical range extension), P. (B.) tritonis Hoek (extension of depth range), P. (B.) tydemani caraibica Stock (second European record, now found at the entrance of the English Channel), and Anoplodactylus arnaudae Stock (range extended to the Rockall Trench).

The potential use of fatty acid (FA) profile as a dietary tracer in juvenile Chinese horseshoe crab Tachypleus tridentatus was assessed in a feeding experiment. Selected feed was provided to the juveniles at various growth stages according to their food sources in the wild: larval and adult brine shrimp Artemia salina for the first six months, followed by a mixture of short-neck clam Ruditapes philippinarum and greasyback shrimp Metapenaeus ensis for a further six months. Juvenile horseshoe crab haemolymph and tissues of book gill, opisthosomal spine, chelicera and swimming leg were sampled after the feeding experiment. The FA profiles revealed that the juvenile haemolymph and various tissues had a total of 23–24 FA components. The major FA components consisted of saturated (palmitic and stearic) at 22–34%, monosaturated (oleic) at 7–34% and polyunsaturated (eicosapentaenoic and arachidonic) FAs at 9–27%. According to principal component analysis, the FA signatures of juvenile haemolymph were greatly influenced by the shift of food sources from brine shrimp to clam and shrimp meat, whereas the FA profiles of different tissues were more resistant to the nutrient alteration. The present findings confirmed that the FA profile of both juvenile haemolymph and different tissues reflected the FA composition of recent and previous diets, respectively; and thus may be useful in indicating the foraging information of juvenile horseshoe crabs in the field.

Several recent papers have dealt with the development of members of the ascidian family Pyuridae (Hirai, 1941; Berrill, 1948; Millar, 1951; Sebastian, 1953), but the total number of species with known larvae is still only five, in spite of the large size of the family.

The present paper deals with the embryonic development, the larva, and the post-larval development of Pyura microcosmus (Savigny).

The mackerel (Scomber scomber) is a pelagic and migratory fish, which during the warmer months of the year frequents the coastal waters in the northern temperate region of the Atlantic. The whole form of the fish is evidently well fitted for swift motion and the free-swimming mode of life. The spindle-shaped outline of the body, its perfect curves and rounded surfaces, the absence of all irregular projections which would tend to retard forward movement, the great muscular development of the tail, and the deep forking of the caudal fin, combine to produce an almost ideal adaptation for propulsion at high speed through the water.

The common goby, Pomatoschistus microps (Krøyer), is a small, euryhaline gobiid fish which ranges along the coasts of continental Europe from the Mediterranean to Trondheim, Norway, and also penetrates into the Baltic Sea (Miller, 1973). This species, which can be very abundant, is generally distributed in estuaries, salt marsh and shore pools (Wheeler, 1969; Miller, 1971) and experiences a higher degree of environmental heterogeneity than most of the other European gobiids (Wallis & Beardmore, 1984a).

The simple piece of apparatus, to which I give the name “Currenttube” was made last year in the Marine Laboratory at Plymouth. I designed it especially for growing Hydroids, and for them it has proved to be a success; but it should also be useful for other fixed organisms, such as sponges, polyzoa, and ascidians.

The previous methods which I had used for growing Hydroids in bell-jars or small aquaria never gave complete satisfaction. Occasionally a success was recorded, but there were too many failures, which frequently involved a great waste of labour.

Moreau (1876), Bohr (1894), and Fänge (1953) are among those authors who have demonstrated that the swimbladder walls of certain fish are highly impermeable to gases. This property assists in the maintenance of high partial pressures of gases in the swim-bladder and enables physoclist fish to use the swimbladder as a buoyancy mechanism, often at great depth. It has been shown experimentally that the swimbladder contains a high percentage of oxygen (Fänge, 1953; Kanwisher & Ebeling, 1957) and that this percentage increases with depth in most fish (Scholander & Van Dam, 1953; Scholander, 1954). Diffusion of gas through a tissue increases with increasing partial pressure difference across the tissue (Krogh, 1919). This may be as high as 10–20 atm in inshore gadoids such as the saithe, Pollachius virens (L.) or 50–60 atm in mesopelagic fish (Kanwisher & Ebeling, 1957). Thus low permeability to oxygen is required if the swimbladder is to be used as a buoyancy mechanism at any depth.

Despite extensive studies on settlement of the cypris larva of Balanus amphitrite amphitrite Darwin (Crustacea: Cirripedia), the fine structure of the putative settlement receptors of this species has not been described. This study presents observations made with the scanning electron microscope of the fourth antennular segment and its associated setae.

Amongst Gunnar Thorson's concluding remarks in his review on marine-bottom communities (Thorson, 1957) he noted that a sequel to the study of macrobenthic parallel communities should be a detailed analysis of the meiobenthos and microbenthos within these communities, adding that the work by Remane and his collaborators in shallow water and on beaches in Kiel Bay indicated that the meiobenthos is likely to show a pronounced uniformity within these communities. Many qualitative sub tidal meiobenthic surveys have followed (e.g. Gerlach (1958) for the nematodes; Por (1964) for the copepods) but it is only very recently that wide-scale quantitative work of the type pioneered by Petersen (1913) for the macrofauna has been applied to the meiofauna (Drzycimski (1969) and Soyer (1970) for the copepods; Ward (1973) and Tietjen (1977) for the nematodes). Around the coasts of Great Britain the only subtidal meiobenthic survey is that by Ward (1973,1975) of the nematode genera of Liverpool Bay, although quantitative faunal and environmental data are available for a number of sublittoral stations (Mclntyre (1964) and Wells (1965) for muddy deposits in Loch Nevis and the Fladen North Sea ground; Warwick & Buchanan (1970) for fine sand and silt deposits off the Northumberland coast; and Mclntyre & Murison (1973) for shallow fine sand in Firemore Bay).

Limaria hians functions as a keystone species in construction of a highly diverse biogenic habitat. An investigation to quantify the biodiversity of two L. hians beds was carried out during the winter and summer seasons at two sites on the west coast of Scotland. Cores were taken semi-randomly through 100% L. hians nest material, organisms removed, identified and enumerated. Univariate and multivariate analyses of the data were used to establish temporal and locational differences. A total of 7275 individuals were found representing 282 species from 16 phyla. Univariate analysis revealed significant differences between the species richness of the two populations, whilst multivariate analysis illustrated differences in the assemblage compositions between sites and times. This study showed that in terms of richness and diversity these beds are among the most important biogenic habitats in the UK.

1. The observed “action at a distance” undoubtedly exists.

2. This action cannot be ascribed to a radiation, nor more generally to an action “through the wall” of the receptacles.

3. This action must then be exercised “across the surface” of the wall of the receptacles by a mechanism which remains to be explained. This seems, however, to be of great interest in view of the apparently very small mass of the substance concerned in the action.

4. The action of something material is rendered probable from the fact that the eggs develop very abnormally in sea-water previously exposed to the active culture.

5. Although these experiments have only been carried out upon sea-urchin eggs, their conclusions may be valid in the case of the very numerous experiments concerning mitogenetic radiation.

A population of the mud shrimp, Upogebia major, inhabiting Kasaoka Inlet had a higher frequency of intersex males compared to other populations in the Seto Inland Sea, Japan. This population also featured a high prevalence of the branchial epicaridean parasite, Gyge ovalis, and inhabited a tidal flat characterized by increasingly softer sediments going into the lower tidal areas. We examined the rates at which infection co-occurred with intersex features and checked whether infection patterns varied with intersex occurrence according to host size and tidal level position. Fewer specimens were both intersex and infected than those having only one of either condition; infection was not a significant predictor of intersex. However, infection in young hosts that recovered from the parasite could be associated with the intersex morphologies and account for the majority of cases that were intersex but parasite-free. Deletions of the cuticular ridge (CRD) between the first and second abdominal segment and tidal level position were correlated with intersex. Lower tidal zone mud shrimp were, respectively, three and four times more likely to be intersex and exhibit CRD than those in the upper tidal zone. Potentially inclusive factors that may influence these trends are higher rates of early infection and increased exposure to sediment-bound pollutants in mud shrimp inhabiting the lower tidal areas.

Spinal cords in deep sea fishes of 37 families have been examined for the presence and relative size of Mauthner axons. No correlation has been found between fish size, and the relative diameter of the Mauthner axon in different species. However, counts of primary motoneuron number and myotomal muscle fibre number in each segment suggest that Mauthner axon diameter is related to the numbers of these in each segment. The behavioural role of the Mauthner system is discussed, and it is concluded that in certain elongate-bodied fishes such as halosaurs and macrourids, a C-type startle response is unlikely.

The area of Christchurch and Poole Bays has been cut by the sea in the period since the breaching of the Chalk ridge between the Isles of Wight and Purbeck late in the Flandrian transgression. Erosion of the soft Tertiary rocks must have been fast and is still active. In the Barton area the cliffs have been receding at about 1 m/year since 1895 (May, unpublished). There the cliffs are composed of badly cemented sands and sandy clays, capped with plateau gravels about 3 m thick, and erosion of them has released large quantities of sand and gravel, sufficient to maintain features such as Hurst Spit. This Spit approaches within 1.3 km of the Isle of Wight, but is separated from it by the tidal channel of the West Solent, in this area up to 60 m deep. In these narrows the south west flowing ebb current reaches 2.25 m/sec, whereas the flood current only reaches 2 m/sec.

When large quantities of bottom soil are brought up by the dredge or grab, the problem of sieving the material within a reasonable time presents itself. The usual practice is to wash the soil through a sieve or series of sieves, the finest being of the order of 1–2 mm aperture, according to the nature of the soil or the size of the animals to be collected. It is usually necessary to agitate the soil either by spraying with a hose or by shaking the sieve in a bath of water, in order that finer particles may pass through the sieve. Many of the more delicate animals are damaged by these methods, and Spooner & Moore (1940), working on the Tamar estuary, found it necessary to mix the mud carefully by hand with water to make a ‘soup’ before it could be sieved without damage to the fauna. For work at sea Hartman (1955) describes a machine by which sieving was accomplished with the aid of water sprays and mechanical agitation of the sieves with power provided by an electric motor.

Broch (1913) described two new species of the coronate scyphomedusa Nausithoë from the North Atlantic, N. atlantica and N. globifera. Bigelow (1928, p. 498) was inclined to think that these two species might finally prove to represent extreme variants of the one species N. rubra Vanhöffen, though a much larger series of specimens in a better state of preservation would be needed to give a definite decision. Kramp (1947, p. 46) considered that N. globifera at any rate was a good species.

The object of these investigations, discussed in full in Part I, is an attempt to correlate the catches of the drift-net herring fishery with the conditions in the plankton at the time of fishing, and if possible to establish useful indications as to suitable and unsuitable waters for fishing. In Parts II and III the zooplankton-herring correlations in the English and Scottish fisheries have been dealt with separately. The phytoplankton material with which this section deals is not so extensive, so that the data from both fisheries will be dealt with together. The pioneer observations of Pearcey (1885) in regard to the herring, of Bullen (1908) inregard to the mackerel, and the fact that fishermen have for long regarded what they call “weedy” or “stinking” water as a bad sign for fishing, have been referred to in Part I, page 148.

Eggs of the syllid polychaete Atnblyosyllis speciosa are deposited in benthic gelatinous masses. Embryos and larvae develop within these masses until about three weeks after fertilization, after which they crawl or swim away and metamorphose. Only one other syllid, the Mediterranean Syllides edentula, has been reported to form benthic egg masses.

While some syllid polychaetes spawn gametes freely into the water column where they are fertilized and develop without additional parental care, most species protect developing embryos in some fashion. Four modes of brood protection have been reported in the syllids. Protection of embryos within the ventral brood chamber of a planktonic adult is characteristic of members of the subfamily Autolytinae, and of some members of the Eusyllinae (Garwood, 1991). Physical attachment of embryos to the body of the maternal parent (external gestation) occurs in all members of the Exogoninae and in a few eusyllines (Heacox & Schroeder, 1978; Garwood, 1991). Viviparity is less common, having been reported in a few species in the subfamily Syllinae (Schroeder & Hermans, 1975; Ben-Eliahu, 1975) and in one exogonine (Pocklington & Hutcheson, 1983). Finally, the formation of benthic egg masses has been described in only one species, the eusylline Syllides edentula Claparède (Cognetti-Varriale, 1971).

In this study the benthic egg masses and development of another eusylline, Amblyosyllis speciosa Izuka, 1912, are described. In December 1995, at the Friday Harbor Laboratories (FHL), Washington, USA, five adult worms were found on a bivalve shell heavily infested with the boring sponge Cliona sp. Additional specimens and egg masses were collected in June 1996 and April-June 1997 from encrusting sponges on the FHL breakwater.