This study examined the relationships between food ration, intra- and interindividual variation in food consumption, observed behaviours and the growth of individual juvenile greenback flounder (Rhombosolea tapirina: Teleostei) held singly and in groups. Agonistic, feeding and neutral behavioural units were identified and described using video records and focal sampling. Agonistic behaviour, including nipping and pushing, were infrequent and accounted for <5% of behavioural units. The influence of food ration upon agonistic behaviour was investigated using three groups of six flounder offered either a low, medium or high food ration. The total number of agonistic behaviours recorded in each group did not differ significantly (P>0.05) suggesting food ration had little influence upon the total number of agonistic behaviours performed. Single flounder showed less intra- and less interindividual variation in day-to-day food consumption than in groups of six. Variation in food consumption increased with increasing food ration in single and in groups of flounder. Significant positive correlations between food consumption, intraindividual variation in food consumption and specific growth rate provided indirect evidence for the presence of feeding hierarchies. The small contribution made by agonistic behaviour to the total number of behaviours recorded for each group suggests exploitation competition, as opposed to interference competition, was the dominant competitive mechanism employed by juvenile greenback flounder.

The escal light glands of some deep sea anglerfishes of the genus Melanocetus were examined by light and electron microscopy. Sections of a larval Melanocetus sp. showed that the gland originates from a solid, branched ingrowth of epidermal cells from the distal surface of the bulb-shaped esca.

The light gland of metamorphosed specimens of M. murrayi and M. johnsoni was found to be constructed in the same way as that of most other ceratioids, i.e. as a branched tubular gland enclosed by a cup-shaped reflector; the radial tubules of the gland open into a central escal cavity, from which a duct leads to an epithelium-lined space, the vestibule, lying above the gland. A duct from the vestibule opens on the upper-caudal surface of the esca.

In the smaller of two specimens of M. murrayi, the epithelium lining the escal cavity and the glandular tubules is of a uniform thickness and structure, consisting of flattened basal cells, cells extending to the lumen, and goblet cells. No bacteria were found anywhere within the esca. The reflector enclosing the gland contains only a few scattered crystals.

In the larger specimen of M. murrayi the distal (terminal) portions of the glandular tubules have tall epithelial cells, while their wide proximal parts and the central escal cavity are lined with a flattened epithelium; goblet cells are absent. Many glandular cells have processes projecting into the lumina. All glandular lumina and the central escal cavity contain numerous rod-shaped bacteria and apparently isolated anucleate cytoplasmic profiles. The reflector is thick and well-developed; each cell contains several staggered layers of crystals.

The conductivity of sand at a depth of 30–50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0·611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0·694. The sand was highly variable in its grain structure. The dominant variability (80·6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (> 1 mm) and small (< 500 μm) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84·1% of the variation in conductivity. Moisture content of the sand (always < 5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

Passive acoustic monitoring of common dolphins was conducted across a survey area of 1000 n.m.2 (nautical miles) off the west Wales coast during the months September, October, November and December 1995. Dolphin presence and distribution was assessed by a system of percentage acoustic contact. Results were compared with those from a seismic/dolphin survey during the same months of the previous year, and across the same survey area. Distributions of common dolphins within the survey area showed similar trends for both years, with a marked decrease in dolphin contacts between September and October of both years. These observations suggest offshore migration of common dolphin populations at the time of year. Sea surface temperature distribution across the entire region was visualized during two survey periods using infrared satellite imagery. It is hypothesized from these observations that offshore migration of common dolphins coincides with a break-up of the Celtic Sea Front, a distinct oceanographic feature which crosses the survey area.

The commonest column colours of Actinia equina (Anthozoa: Cnidaria) are various shades of dark red or brown. However, these colour forms conceal genetically differentiated upper (U), mid (M) and lower (L) shore morphs. It is now evident that these morphs have differing ecological requirements and probably constitute different biological species. Identification by examination of diagnostic gene loci is not practicable for most ecological purposes. The L morphs can be readily identified, but there is no known morphological character to distinguish reliably between the U and M morphs. A study of acrorhagial characters indicates that, whilst neither the type, number, colour nor size of the acrorhagi themselves were diagnostic, there is a clear difference between the U and M morphs in the size of the holotrichs (a category of nematocyst). The holotrichs were significantly smaller in the U morph than in either of the other two morphs. In the M and L morphs the holotrichs did not differ significantly in size.

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.

The scaleworm genus Pholoe (formerly referred to Sigalionidae) is common and often abundant in marine benthos. In northern Europe, 1–3 species may be present in a single sample but not recognized as distinct, or one species may be reported under different names in different studies. This results in an underevaluation of diversity and precludes comparison between data sets. Four valid species of Pholoe are common in nearshore European waters, but inadequate descriptions and species misinterpretation have resulted in most of these being misidentified as the western North Atlantic P. minuta, not known to occur in European waters. The present note attempts to resolve this confusion; it is based on examination of thousands of specimens, many of them alive, from northern Europe and elsewhere. An illustrated key and notes with brief synonymies for four nearshore northern European species are provided; use of Shirlastain A for temporarily darkening protruding structures is described. Pholoe inornata (type species of the genus), P. baltica and P. assimilis (resurrected) are briefly characterized.

Seasonal variation in the abundance of marine plankton taxa is commonly expressed in the form of ‘mean annual cycles', in which the mean abundance over several years for a particluar season is plotted against the time of year. Typically, such mean annual cycles are used to compare patterns between different spatial locations. We wish to argue, however, that this can be very misleading since the shape of the underlying seasonal cycle itself may change with time as well as location. Thus, it is possible that the mean annual cycle may never actually occur in the environment in any location, nor need it characterize the underlying cyclicity in any one year. Moreover, ignoring changes in the shape of seasonal cycles over time can obscure important demographic shifts in plankton populations. It is therefore essential to test statistically for any changes in the shape of annual cycles before assuming their stability through time. Here we report on continuous plankton recorder (CPR) data of the calanoid copepod Calanus finmarchicus in which there is a demonstrable change over time in the pattern of seasonal fluctuations in abundance, and we discuss briefly the demographic implications of this change.

Introduced for aquaculture purposes, Ruditapes philippinarum has naturally recruited in several areas along the French Atlantic coast, and is subject to recurrent mortalities in late winter. The possible impact of these mortalities on both newly settled spat and juvenile R. philippinarum, was examined in a population from the Bay of Brest (western Brittany), in parallel with a survey of the main environmental parameters. From February to March 1994, 84% of the juvenile clams, between 1 and 2-y old, disappeared. No direct link could be made between these mortalities and the environmental parameters. Such winter mortalities were not observed in the newly settled spat.

The diet of Synaphobranchus kaupi from the Porcupine Seabight is described. A sample of 110 eel stomachs containing food, were analysed and the general size–depth trend among eels with food in their stomachs. Larger individuals are found in deeper waters. Fish are the main prey for larger eels and crustaceans are preferred by smaller individuals.

Synaphobranchus kaupi Johnson, 1862 is a slope dwelling eel, abundant in the north-east Atlantic Ocean from 230 to 2420 m deep on the continental slope (Haedrich & Merrett, 1988). It is the most abundant species on the slopes of the Porcupine Seabight, off south-west Ireland (Merrett et al, 1991; Priede et al., 1994) and was classified as a benthopelagic predator of the fourth level, predator of predators (Saldanha, 1991).

The diet of S. kaupi has been described from the slope off the middle Atlantic coast of the USA (Sedberry & Musick, 1978), from the Portuguese slope and in the Bay of Biscay (Saldanha, 1991), from the west African slope (Merrett & Marshall, 1981; Merrett & Domanski, 1985) and from the Rockall Trough (Gordon & Mauchline, 1996).

Our specimens were captured during a joint IOS/SAMS survey (Merret et al., 1991). From a total catch of 8792 S. kaupi, captured between 1979 and 1983 in the Porcupine Seabight, ranging from 470 to 2230 m deep, fish stomachs were removed aboard ship and 110 with food were kept in 5% formalin for further analysis.

A cumulative species description curve (from 1830 to 1995) is given for open water marine fauna in excess of 2 m long in the major axis of the body. This curve has not yet closely approached its asymptote. Estimation by maximum likelihood fit of a hyperbola suggests a maximum of some 47 species awaiting formal scientific description and an approximate current rate of description of one new species every 5·3 years. Consideration of the most recently described species and recent observations by field workers suggests that any imminent species descriptions are most likely to be cetaceans.