The white-beaked dolphin, Lagenorhynchus albirostris, is commonly found throughout the North Sea and shelf waters of the North Atlantic. Little is known about the behaviour and ecology of this species, especially in British coastal waters. In this paper we present details of the seasonal and geographical distribution of white-beaked dolphins around the UK, along with new information on their diet and habitat use. Analysis of historical stranding records show a segregation of the sexes, with a significant difference between when males and females strand in UK waters. There has been a steady decline in reported strandings since the 1970s and seasonal differences in the distribution of strandings suggest that sea temperature may limit white-beaked dolphin distribution around the British coast. Stomach contents' analysis, from dolphins stranded mainly on the Scottish east coast, identified haddock and whiting as the predominant fish species being taken. Boat surveys were performed along the north-east Scottish coast to examine relationships between topography, environmental conditions, dolphin presence and group size. Dolphin presence was related to seabed slope and aspect while variation in temperature explained almost 45% of variation in observed group size, with smaller groups associated with higher sea temperatures.

The present study analysed the reproductive biology of Callinectes danae and Callinectes ornatus, which are captured as by-catch from pink-shrimp trawling in Guanabara Bay. The size at gonadal maturity was 79.9 mm and 67.4 mm respectively, for C. danae and C. ornatus. The pattern of reproduction was continuous for both species; however, the gonadosomatic index analyses showed seasonal and alternating reproductive peaks in the bay. While C. danae showed reproductive peaks in the autumn and in the winter, C. ornatus showed an apparent reproductive peak in the summer and probably another in the spring. The sex-ratio of C. danae was significantly skewed in favour of females (3.0:1). However, in C. ornatus, males predominated (1.2:1). This reproductive pattern indicated that possibly the females of C. danae return to the estuary after spawning where trawling takes place, while ovigerous females of C. ornatus migrate to adjacent coastal areas around the bay.

Ovaries of the common sole (Solea solea (Linnaeus)) were collected prior to, or at the beginning of, spawning from the spawning grounds in the Bristol Channel. Size frequency distributions of oocytes over 100 μm are presented. They clearly show a break in the size frequency distributions, at about 170 μm, indicating that the production of new oocytes to be spawned that season had ceased. It indicates that the sole is a determinate spawner and that, at least for this population, an annual potential fecundity can be measured. Estimated annual fecundity at length of Bristol Channel sole is calculated, and values are compared with those found for sole from the North Sea, eastern English Channel and the Bay of Biscay.

It has been observed that the pH in the different parts of the alimentary canal of Corophium is nearer neutrality; while the medium in the ventral hepatopancreatic caeca is more acidic, being in the neighbourhood of 6.2.

Investigations on the qualitative estimation of enzymes indicate that none of the enzymes are secreted by the gut proper. However, the ventral caeca only secrete many of the carbohydrate splitting enzymes; proteases and lipase are also secreted by the caecal cells of Corophium

It has also been estimated that the optimum pH for the activity of the caecal amylase lies in the neighbourhood of 5.8.

The life-history of hydroids from a mixed population of Tubularia indivisa and ‘T. ceratogyne’, from an intertidal site at Felixstowe, Suffolk, has been studied. Tubularia breed throughout the year, but recruitment is greatest in spring with a smaller peak in late summer. The spring-recruited hydroids are the progeny of T. indivisa, but during the summer they mature as ‘T. ceratogyne’ and breed to produce the T. indivisa that dominate the population in spring. It is concluded, on this evidence, that ‘T. ceratogyne’ is a form of T. indivisa.

In this population T. indivisa suffers from predation by the nudibranch Dendronotus frondosus, and their mortality rate varies from 2% per month in winter to 70% per month in summer. The life-span of T. indivisa is approximately one year, but their mean post-larval life expectancy varies from 30 days (spring recruitment) to 160 days (autumn recruitment). There is no evidence that autotomy of the hydranth is an integral part of the life of T. indivisa.

1. An ecological survey of the fauna of Dingle Beach, Mersey Estuary, has been made.

2. A detailed analysis of the constituents of the mud, sand and gravel is given.

3. A quantitative analysis of the Molluscan fauna from a series of stations has been made.

4. Type of ground and fauna at different tidal levels are correlated.Mya arenaria is only found in abundance where there are stones. Macoma balthica is abundant wherever there is thick mud.

5. Dingle Beach is a type of Macoma community but differing markedly from the typical community described by Petersen as “d”.

6. The importance of sewage in producing silt and the part played by sewage in the food chain are discussed.

Presence of O-group bass, Dicentrarchus labrax (L.), has been recorded for a number of estuaries and tidal backwaters in the south of the United Kingdom, including the tidal Thames (Wheeler, 1979), the outer Thames at Southend (Murie, 1903), the Medway (Van den Broek, 1979), Langstone Harbour (Reay, 1973), the Dart (Dando & Demir, 1985), and the Tamar (Hartley, 1940). The author has found them, additionally, in Chichester Harbour and in the Cuckmere (Sussex), Teign and Tavy estuaries. Correspondents have reported them from the estuaries of the Blackwater (Cox), Crouch (Wiggins), Lynher (Gee) and Fal (Melhuish); also from the Fleet backwater in Dorset (Fear). It may be inferred that all estuaries and tidal backwaters on the south and south-east coasts of the U.K. constitute bass nurseries, in some degree.*

Benthic nematode and macrofaunal communities are regularly utilized in impact studies. However, very few studies are carried out utilizing both communities. A literature search using the search engine Scopus (www.Scopus.com) covering the last twenty years, using the keywords ‘Macrofauna’ and ‘Disturbance’ then ‘Meiofauna’ and ‘Disturbance’ and finally ‘Macrofauna and Meiofauna’ and ‘Disturbance’, gave 210, 115 and 36 hits respectively. To assess the differential response of meio- and macrofauna to in situ burial a replicated random block designed field experiment was carried out over a 9-month period on an intertidal mud flat. In situ burial was achieved by spreading 4 cm of anoxic mud on top of each treatment plot at two different intensities. Differences in the response of the two faunal communities over time were assessed using both univariate and multivariate techniques. Clear differences in community behaviour over time and in response to the different intensities of disturbance were observed. Overall macrofauna were found to be more sensitive to physical disturbance than meiofaunal nematodes, although, attributes of meiofaunal nematode communities were more sensitive to the initial impacts of disturbance. The observed community-specific responses and sensitivities of meiofauna and macrofauna to the physical disturbance associated with in situ burial highlights the importance of using both faunal types in the assessment of the effects of seabed disturbance in the marine environment.

A population of the neogastropod Ocenebra erinacea sited close to the shipyard at Falmouth (Cornwall: south-west England) has been monitored over a period of 20 years for the effects of exposure to the antifouling agent tributyltin (TBT). During the years 1986 to 1995 the proportion of females sterilized through abnormal development of the oviduct increased from 36% to 87%. Despite legislative restrictions on TBT paints, in 2006 there was little improvement in the reproductive capacity of the population in that over 75% of females still showed the same abnormality. At the sampling site, levels of TBT in surface water had a background of around 2 ng Sn l−1 throughout the period of study with higher peaks up to 50 ng Sn l−1. Much of the TBT pollution in the Fal estuary and environs in recent years appears to be the result of discharges from the shipyard at Falmouth within the estuary.

Parathemisto gaudichaudi (Guerin) (= P. gracilipes, Sheader & Evans, 1974) is a species of planktonic hyperiid amphipod which occurs in temperate and subpolar regions in both hemispheres (Dunbar, 1964; Kane, 1966; McHardy, 1970, Ph.D. thesis, Edinburgh University).

Our previous studies have dealt with the taxonomy (Sheader & Evans, 1974), feeding and gut structure (Sheader & Evans, 1975), and morphological variation (Sheader, 1975) of P. gaudichaudi. These studies involved the routine maintenance of the species in laboratory conditions, allowing behavioural and developmental data to be gathered. The present paper deals with fertilization of the eggs and subsequent development up to the time of release from the marsupium. Animals were collected at a station 5 miles east of Blyth, Northumberland (55° 07′ N, 1° 22′ W). Laboratory culture is described in previous papers (Sheader & Evans, 1974, 1975).

Two forms of Venerupis rhomboides occur in Plymouth waters. A more slender form, corresponding to that described by Pennant, occurs in the Eddystone shell gravel, and a more robust form, corresponding to the Venus sarniensis of Turton, occurs at the mouth of the River Yealm. The two forms differ in ratios of shell height, width and lunule width relative to shell length. A population with intermediate ratios is found at 6-5 m in Plymouth Sound.

Plots of height/length ratios of these and another intermediate sample on probability paper did not indicate that the intermediate populations were composed of mixtures of the two extreme forms, and it was provisionally concluded that these were all variants of a single species.

If the height/length ratios of series of samples from different localities are plotted against depth of water on a logarithmic scale, an inverse relationship, approaching a straight line, is obtained. Regression lines for median ratios in the 3-4 and 4-5 cm length groups have been plotted separately, as there is some change in proportion with increasing length. These show a highly significant negative correlation between shell ratios and depth.

From the regression lines it has been possible to obtain an estimate of the depth inhabited by even quite small samples of shells. Depth estimations have been made for eight samples, consisting mainly of dead shells. Six samples lay within the expected limits, and discrepancies in the other two samples are attributed to transport along the sea floor.

The possible causes of the differences in shell ratios are discussed. Previous work suggests that shell ratios may be affected by different rates of growth. Soil grade, temperature, food supply, and light penetration are considered unlikely causes of the observed differences in shell ratios, and it is suggested that the pattern of growth may be affected by pressure.

The Appendix contains a key to British species of Venerupis.

Size at morphological sexual maturity, sex-ratio, and the seasonal variation in abundance of the shrimp Artemesia longinaris Bate, 1888 were assessed off Pinheira Beach, Palhoça, Santa Catarina southern Brazil. Shrimp were collected monthly from November 2003 through to October 2004, in two areas that are customarily used by local traditional fishermen (27°52′–27°51′S and 48°33′–48°29′W). Of the total of 1099 specimens measured, 23.93% were males and 76.07% females. Mean size at first maturity (LM50) was estimated as 56.38 mm total length (TL) for males, and 70.34 mm TL for females. Females were significantly larger than males. Abundance of juveniles varied seasonally. A high predominance of juveniles in the areas sampled occurred in winter for both sexes, and in spring for females. In the summer and autumn, we observed a decrease in juveniles in both areas, mainly, area II. We suggest that the differential migration pattern of sexes during the reproductive cycle was the principal reason for the larger catch of females. The classical paradigm of continuous reproduction at lower latitude, with increased seasonality of the breeding period at higher latitudes, seems to apply to this species.

INTRODUCTION

It has long been known that the ears of clupeoid fishes differ from most other fish in that they have a gas-containing bony bulla associated with each ear (for references to early work see Allen, Blaxter & Denton, 1976). The expansion and contraction, with changing pressure, of this gas causes liquid to flow in the ear and lateral line (Gray & Denton, 1979; Denton, Gray & Blaxter, 1979) thus causing displacements (Best & Gray, 1980) and excitation (Denton & Gray, 1980) of the utricular maculae; it also causes excitation of the lateral line neuromasts (unpublished). Only a small fraction of the alternating liquid flow from the bullae passes through the pars inferior of the labyrinth (Gray & Denton, 1979). Furthermore, in larvae, when the utricular structures can be seen to move vigorously with an alternating pressure the saccular otolith is not seen to move (Blaxter, Denton & Gray, 1981).

A total of 235 bullet tunas (Auxis rochei) was caught off the north-eastern coast of Sicily between March 2003 and March 2004 for the purpose of studying their feeding habits. The fish were caught by means of an experimental surface gill-net during fishing surveys carried out on a monthly basis. The stomach contents were analysed and the prey identified, counted and weighed. The importance of the different prey types was assessed utilizing several feeding indices while possible size-related changes of the diet composition were highlighted by means of hierarchical cluster analysis, nMDS and SIMPER analysis. The results of this study showed that the bullet tuna is an epipelagic off-shore predator feeding on whatever abundant resource is available in the environment with a preference for planktonic crustaceans, small cephalopods and fish larvae. Among crustaceans, hyperiidean amphipods were the most important prey, with Anchylomera blossevillei as the dominant species, followed by the euphausiacean Stylocheiron maximum. Among cephalopods, Heteroteuthis dispar was recorded frequently while fish larvae showed high values of all indices. All prey were pelagic organisms. A size-related change in the diet composition was observed, even if it seemed related to the temporal fluctuations of the zooplanktonic assemblage in the environment. The average prey weight per stomach increased significantly in the larger predators which mostly fed on fish larvae belonging to several commercially important demersal and pelagic species.

The reproductive strategies of male and female Loligo forbesi Steenstrup, 1856 were investigated from samples obtained from commercial catches and research cruises in Irish waters. In females maturity increased with size, but in males two modes in the size at maturity were identified, with approximately 40% mature at small size (180–200 mm mantle length), and the remainder mature at >250 mm mantle length. The difference in estimated age of the two modes of mature males was small, so size differences were probably due to different growth rates. Growth and maturation proceeded together in both sexes over much of the life-cycle. The effect of maturation on relative growth of somatic tissues was examined using analysis of covariance and multivariate regressions. In males there was a significant decline in total mass, and in mass of mantle, head and viscera, relative to mantle length with maturation. In females total mass was not significantly affected by maturation, but relative masses of head, mantle and viscera declined with maturation, indicating that energy was diverted from somatic growth to gonad production. Potential fecundity estimates were obtained by counting eggs and ova in the oviduct and ovary of mature females and were in the range 2500 to 10,500 (mean 5800). Fecundity was positively related to mantle length. The ovaries of mature females contained a range of egg sizes and developmental stages, indicating that spawning probably occurs intermittently.

In November 1969 on ‘Discovery’ Cruise 30 a day and a night series of hauls were taken with the RMT 1 + 8 net system (Baker, Clarke & Harris, 1973) in the region of the Cape Verde Islands. The cyclopoid copepods from the two series have been examined and this account describes their depth distributions, vertical migration patterns and community organization. Some taxonomic observations on one family, the Oncaeidae, have already been published (Boxshall, 1977).

Understanding the role played by sunken vessels in Mediterranean marine ecosystems is acquiring increasing importance. The aim of this research was to study the fish communities associated with four shipwrecks, by means of underwater visual censuses performed by a remotely operated vehicle, and to test the differences in composition of fish assemblages between these shipwrecks and the adjacent soft bottoms, considered as control sites. Multivariate analysis on the total fish assemblage showed significant differences between wrecks and controls. Results also showed higher levels of species richness and abundance near all wrecks than at a short distance from them on soft bottoms, thus indicating that these sunken vessels, thanks to their higher habitat complexity, act as artificial reefs, attracting aggregations of fish species and leading to a greater diversification of the local fish assemblage. Nevertheless, shipwrecks, which are an ideal target for recreational fishermen, could contribute to the over-exploitation of some high-value fish species, such as Mycteroperca rubra, Dentex dentex and Diplodus spp., attracted by the artificial hard substrate of the vessel-reefs. The recent European directives suggest an urgent need for a better understanding of the crucial role played by these potential sources of pollutants on marine environments and ecosystems. An ecosystem approach to study and monitor these pollutant sources is, therefore, mandatory for appropriate remediation and/or mitigation of the potential negative effects on a productive and healthy ocean.

We use a bootstrap simulation framework to evaluate the relative importance of different sources of random and systematic error when estimating diet or food consumption of cetaceans, using a data set on harbour porpoise diet in Scottish (UK) waters from 1992–2003 (N=180) as a model. We also evaluate the consequences of applying explicit weightings to individual samples and/or sub-sets (‘strata’) of samples. In terms of the precision of estimates of diet composition, sampling error was the most important source of error, to the extent that overall 95% confidence limits changed only very slightly when sub-sampling error and regression errors were taken into account. On the other hand, for estimates of total food consumption by the porpoise population in Scottish waters, uncertainties about population size and energetic requirements were more important than uncertainty about diet composition. In relation to the accuracy of estimates of diet composition, the study also highlighted the importance of selecting regressions appropriate to prey in the study area (as opposed to ones constructed for the same prey species in another area) and demonstrated that applying equal weighting to individual samples or sample strata can substantially alter the resulting picture of diet. Therefore, the rationale for applying such weightings needs to be carefully considered.

The mobility and quantity of retinula cell proximal screening pigment, and the liability of the eyes to light-induced damage, were investigated in the Norway lobster, Nephrops norvegicus (L.), obtained from three separate populations from depths of 18, 75, and 135 m.

During the morning after capture, the migration of the proximal pigment in response to the onset of illumination below the threshold for damage varied between the three populations. In the eyes of deep water N. norvegicus, the proximal screening pigment was located close to or below the basement membrane when dark-adapted and rose to a position midway up the rhabdoms when light-adapted. In the dark-adapted N. norvegicus from shallow water the proximal pigment was located more distally than in eyes of deep water animals. After the onset of illumination, the pigment migrated distally to completely cover the rhabdoms. The amount of retinula cell proximal screening pigment was found to decrease linearly with depth.

When dark-adapted individuals from each depth were exposed to light a positive correlation was obtained between the photon fluence rate (PER) and the proportion of the retina damaged. For a given light exposure the amount of damage was highest in animals from deeper water. The PFR causing 25% damage was approximately 1 log unit higher in animals from 18 m compared to those from 135 m.

The amount of damage varied with the delay between capture of the animals and exposure to light. When exposed 2 h after capture significant differences between depths were seen but the results were influenced by the incomplete dark adaptation of some specimens.

The common phenomenon of sublethal predation in soft-bottom bivalves usually involves nipping of siphons. Here we show that foot cropping, hitherto documented only in Donax spp., is widespread in the New Zealand cockle Austrovenus stutchburyi (Veneridae). Depending on the locality, cropping frequency ranged between 14 and 34% of cockles, and the average proportion of the foot area cropped ranged between nine and 21%. Estimates of biomass lost to croppers at the time of sampling varied between 235 and 2040 mg ww m−2. It is emphasized that foot cropping in Austrovenus is likely to affect the population dynamics of the cockles.