Stauromedusae are cnidarians that have attracted relatively little ecological study, especially in the southern hemisphere. They are Scyphozoa that develop directly from the scyphistoma, and each consists of a calyx and a more or less distinct aboral peduncle that attaches to the substratum by an adhesive disc. The animals are mobile on the substratum, but have no pelagic phase. The present note originates from observations made on stauromedusae living in intertidal and shallow subtidal waters at Husvik Harbour, South Georgia (54°11′S 38°40′W) in early 1994. The species concerned was identified from Kramp (1961), Carlgren (1930) and Pfeffer (1889) as Haliclystus antarcticus Pfeffer, 1889. This species has attracted little previous study. The most detailed anatomical description was given by Carlgen (1930), while distributional details are given in O'Sullivan (1982) who followed Pfeffer (1889); at present there is no evidence that the species occurs other than at South Georgia.

Medusae were found on two substrata. Large animals (~30mm high, inconspicuous dark brown in colour) were found on the underside of boulders at extreme low spring tide level in a bay on the north of Husvik Harbour about 1·2 km from the whaling station and close to Brain Island. Locally they were common, often being close enough to touch one another. Smaller animals (pink-orange in colour; cryptic on the macroalga) were found attached to the brown macroalga Desmarestia menziesii J. Aghardh (Phaeophyceae) collected at low-water spring tide level from Kanin Point on the southern shore of the harbour. Medusae on boulders were briefly emersed on particularly low tides: they collapsed, hanging from the peduncle, when out of water, but did not risk desiccation as their habitat was wet and not exposed to the sun.

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 carapace lengths, dry weights, carbon content and nitrogen content of decapod larvae sorted from fresh plankton samples were measured. Regressions for the relationships between dry weight and carapace length were determined for each infraorder and for lower taxa. Regressions between carbon content, nitrogen content and C:N ratio and dry weight were calculated for the different taxa and were compared with published data on larvae reared in the laboratory.

Decapod larvae often comprise a significant component of the zooplankton of estuaries and inshore waters (Lindley et al., 1994). Lindley (1988) has presented data on the relationship between dry weight and carapace length for brachyuran larvae from the plankton. Similar data for other groups of decapods and additional data and analyses for brachyurans are presented here with data on carbon and nitrogen content. Anger & Harms (1990) described the relationships between dry weight; carbon and nitrogen content for decapod larvae reared under controlled conditions in the laboratory. The results of measurements on specimens caught in the plankton in naturally varying conditions provide a comparison with laboratory reared larvae. Harms et al. (1994) compared dry weights and biochemical data for Carcinus maenas (Brachyura) larvae reared in the laboratory with specimens from the plankton off Helgoland. Dry weights of the last two zoea stages and the megalopa larvae from the plankton were higher. The percentage carbon, nitrogen and lipid content were higher in laboratory raised larvae which were fed on Artemia nauplii than in field specimens or in laboratory reared specimens fed on phytoplankton or starved.

Mortality patterns of marine turtles entangled in fishing gear, found dead at sea or stranded dead on and around the coast of Britain in the period 1992–1996 are described. Of a total of 38 dead turtles identified, 35 were leatherback turtles (Dermochelys coriacea) and three were loggerhead turtles (Caretta caretta). All D. coriacea were considered adults or subadults nearing sexual maturity. Six individuals were assessed as females, ten were classified as males and 19 were not sexed. Dermochelys coriacea (N=20 measured) ranged from 120 to 210 cm in curved carapace length (mean, 152 cm). The three C. caretta were juveniles, and ranged from 15 to 30 cm curved carapace length. Possible origins, causes of mortality and interactions with fisheries are discussed. In addition, contaminant levels were determined in the tissues of three D. coriacea. Concentrations of organic contaminants determined were found to be low.

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.

In the Forth Estuary, Scotland, parasitic rhizocephalan barnacle Sacculina carcini externae or scars occurred on 64% of Carcinus maenas from the subtidal channel of the middle estuary. These became more frequent downstream, infecting 46·9% in the lower estuary basin. Male and female crabs were infected equally, and infection rates in low-tide samples did not differ from high-tide. The parasites occurred most frequently on crabs of 40–50 mm carapace width (CW) rather than the modal crab size class of 50–60 mm. Downstream, proportionately more smaller than larger crabs bore parasites whereas, further upstream, more larger than smaller crabs bore parasites. There is evidence for the annual appearance of new externae in July-October, especially in the lower estuary basin, followed by their growth and loss after about a year.

Large catches of sole (Solea solea) were made in early 1996 from the south-western North Sea. Sole suffer physiological damage in waters below 3–4 C. In February 1996 cold water of 3–4 C unusually extended from the Continental coast onto the Dogger Bank. It is likely that the increased catches were due to the consequential distribution and behaviour of the sole, making them more susceptible to capture.

Exceptionally large catches of mature sole (Solea solea (L.)) were made in February 1996 by Lowestoft fishermen from the south-western North Sea. Surprisingly this was not welcome. The UK allocation of the North Sea sole is -4 % of the EU Total Allowable Catch (TAC), and fishermen are restricted nationally, and by the fishing companies, to a tightly managed ration. The Lowestoft Journal (8 March 1996) reported the suspension of a local fishing skipper for not throwing back 5000 kg of sole caught in the Silver Pits. We will show that the abnormal catches were due to exceptionally cold waters.

Sole in the North Sea are at the northern extremity of their range, with sole seldom living in waters below 5°C (Horwood, 1993). In fact, North Sea sole were successfully introduced into Lake Quarun, Egypt, where they lived in temperatures in excess of 30°C (El-Zarka, 1965). Young sole migrate from their shallow inshore nursery grounds, such as the Waddensea, as winter approaches (Creutzberg & Fonds, 1971).

Geographical morphological variations in Fucus vesiculosus populations were studied along the coast of Iceland. Principal component analysis (PCA) based on 11 morphological characters clustered the 26 sampling sites into four different morphological types as follows: (1) a morphological type found along the S-SW-W coast; (2) an intermediate form comprising only two populations in the NW; (3) a type found along the N-NE-E-SE coast; and (4) a type found independent of geographical area, in estuaries and at sites influenced by large freshwater outflows. Populations influenced by low salinity had significantly (P ≤ 0·001) shorter thalli, a shorter distance from the holdfast to the oldest dichotomy, smaller fronds, narrower stipes and midrib width compared to the morphology of all other more saline populations. No significant difference in frond width was found between the S-SW-W and the N-NE-E-SE populations. However, significant (P ≤ 0·001) morphological differences between them were observed, the former having shorter thalli, a greater distance from the holdfast to the oldest dichotomy, narrower stipes and smaller midrib width compared to the latter.

Buried individuals of the bivalve Donax vittatus (Bivalvia: Donacidae) respond to change in incident light intensity by adjusting their position in the sediment. Video recordings of activity in aquarium tanks in natural daylight revealed that individuals responded to shading by moving upwards, causing some to partially emerge from the sand. Subsequent removal of the shading stimulated reburial to the normal position. Recordings in laboratory aquaria show similar upward movement and partial emergence occurring when illumination in the visible range is switched off. Upward movement and partial emergence of D. vittatus has also been observed to take place prior to spawning.

Discriminant function analysis was used to identify two morphotypes of Fucus spiralis (Phaeophyta: Fucales), F. spiralis forma spiralis and F. spiralis forma nanus, within a single population. Evidence was found that they are true formae, not extremes of a range of types produced in response to environmental gradients. Forma spiralis tends to be larger than forma nanus, and to dominate the lower part of the species distribution on the shore. However, size alone appears insufficient to reliably separate the two formae given their high degree of morphological variability.

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.

Observations on samples from Spanish trawlers between September and November of 1995 revealed the presence of mated females of Loligo gahi (Cephalopoda: Loliginidae) from 164–285 m depth, in the Western area of the Falkland Islands Conservation Zone. 93.8% of the mature females, and 31.0% of the maturing ones, were mated. Deposition of spermatophores always took place in the oral membrane between the connectives of arms IV. The relationships between sexual maturation and copulation have been analysed, and the hypothesis of mating acting as a ‘trigger’ of the final sexual maturation in Loligo gahi females is proposed and discussed.

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.

Thioploca are sulphur oxidizing-nitrate reducing gliding filamentous benthic bacteria belonging to the Beggiatoaceae. In this paper we report on the discovery of Thioploca resulting from a commercial fishery survey of Trachurus capensis (horse mackerel) and Merluccius capensis (hake) carried out off Namibia between 18°00·1′S and 25°00·8′S from 4–10 December 1996, on board the RV ‘Welwitschia’. The first positive finding of sheathed, presumably vacuolated, Thioploca in the Benguela Current ecosystem is now reported.

Various marking techniques have been used in ecological studies of starfish as well as other benthic animals (Nielsen, 1992). They include the attachment of tags (Feder, 1955), staining with dye (Hancock, 1958), inscription with sharp pencil (Scheibling, 1980), and branding (T.K, unpublished data). These methods have been used in mark-recapture surveys over durations of several days in order to study the diurnal activity rhythmn (Burla et al., 1972), movement after displacement (Pabst & Vicentini, 1978), and feeding and movement rates (Keesing & Lucas, 1992). However, these marking techniques on starfish have never been quantitatively evaluated for their durability and detrimental effects on the starfish.

Accordingly, in the present study, brand marks on Asterina pectinifera (Müller & Troschel) were examined in the laboratory in terms of their durability and impact on mortality and growth. For Echinodermata, branding has been used mainly on Holothuroidea like Stichopus japonicus (Arakawa, 1990). However, it can also be used for starfish to identify individuals by marking patterns on the body (T.K., unpublished data). The present study tested the effects on the growth and mortality of A. pectinifera. It also examined the durability of brands for distinguishing individuals of a branded group from individuals of an unbranded group, and the durability for identifying individuals with specific coded brand marks.

Two hundred starfish were collected in Maizuru Bay (35°29′N 135°22′E) in September 1995, and the size was measured. The five arms of each individual were measured from the centre of the disc to the arm tip (mm) to determine the mean radius (R0).

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.

Mysids (Paramesopodopsis rufa) were tethered in both swarm and school formations in a flow tank to test whether food capture was influenced by orientation or position in the aggregation. Neither orientation nor position exerted a significant influence on food capture success. However, the two formations differed in that certain positions in the polarized configuration were significantly correlated. In addition individuals at the front of the aggregation captured more food (though non-significantly) with a significantly higher degree of variation. This experiment has demonstrated the feasibility of measuring food capture success in different locations within an aggregation of crustaceans.