A numerical model is used to demonstrate wave trapping of the diurnal tides on Porcupine Bank and Rockall Bank. These waves have wave lengths of about 300 km and travel along the sloping topography with shallow water on their right. On the slopes of Porcupine Bank the shorter period K1 wave has a longer wavelength than the O1 wave and so here the trapped diurnal spring-neap signal propagates in a direction which is opposite to the phase velocity.

Techniques were developed to measure the adhesion of the barnacle Balanus balanoides (L.), over the post metamorphosis period. It was found that Balanus balanoides is capable of producing a proteinaceous adhesive material within one day of metamorphosis. This adhesive material was found to withstand applied forces of 1·7×105 Nm−2 before cohesive failure took place. The strength of the cement produced by older barnacles, measured at a time when the adult cement apparatus is known to be operating, was considerably greater and applied forces of 9·3 × 10 Nm were necessary to induce cohesive failure in the cement. The strength of B. balanoides cement was thus shown to be at least one tenth of that of commercial adhesives which have tensile strengths in the region of 107 Nm−2.

Samples of the deep-sea forcipulate seastars Brisinga endecacnemos, Brisingella coronata, Freyella spinosa and Zoroaster fulgens have been collected at a number of stations in the N.E. Atlantic. Examination of their reproductive biology suggests subtle interspecific variations in their gametogenic cycles. The gonads of Brisinga endecacnemos are serially arranged under the dorsal arm surface, each cluster of gonad tubules having its own gonopore. In the closely related Brisingella coronata each gonad consists of up to 12 elongate tubules opening at a single gonopore at the dorsal surface. In both species the maximum egg diameter is about 1250 μm and fecundity may be up to 60000 eggs per individual. It appears that the eggs in Brisinga endecacnemos are produced in clusters whilst those of Brisingella coronata are produced continuously. InFreyella spinosa the gonad consists of a small tubular sac analogous to a single tubule of Brisinga endecacnemos. Maximum fecundity is only 2500 eggs per individual, and the maximum egg size is 1250 μm. In all three species eggs that are not spawned undergo internal oocyte degeneration. The gonads of Zoroaster fulgens show the typical asteroid configuration of two at the base of each arm, one either side of the ambulacrum. The maximum oocyte diameter is 950 μm. There is some evidence that there may be a seasonality of reproduction in this species. In all four species examined the large egg size and relatively low fecundity suggest direct demersal development with the subtle variations in their reproductive biology reflecting slightly different breeding habits.

Seven species of the amphipod genus Ericthonius are described and figured from the North-east Atlantic and associated seas and a key to their identification is provided. West Atlantic material is also considered where relevant to the taxonomy of East Atlantic species. Two species are re-established after a long period of submersion in synonymy, and one species new to science is described. The previous confusion in the literature of some of the species is discussed, and a synonymy of species described in key works is provided.

Nephtys pente sp.nov. is described. The species is known to occur in shallow waters from the western Baltic to Greenland. It may occur with Nephtys ciliata, which it closely resembles. An amended definition for N. ciliata is proposed. A key is provided for the northern European species of Nephtys.

In experiments to investigate the effect of low salinity on growth in Mytilus edulis, unexpected depression of growth occurred, even in sinusoidal regimes falling to only 90% of the full salinity, when tap water was the diluting medium used. The effect of various additives to the domestic water supply on the growth of Mytilus was investigated. Chlorine and fluoride had no effect although fluoride (as sodium fluoride) inhibited faeces production in a 7-day experiment. Determinations of the level of copper in the laboratory's tap water showed these to be high enough to cause depression of growth even at low dilution levels. When distilled water or lake water was used to dilute the sea water, shell growth was not affected until a sinusoidal fluctuation reaching a minimum of 50% sea water was used. Such effect did not become significant until the mussels were kept in pure fresh water for an extended period in each cycle of sinusoidal salinity variations.

Kingsnorth Power Station, on the River Medway Estuary, Kent, discharges cooling water into a canalcomprising a 4 km creek system. A comprehensive investigation of the sublittoral benthic fauna of the discharge system was undertaken from January 1979 to September 1981. The benthic macrofauna was sampled monthly at five stations along the system and a sixth in the River Medway adjacent to the creek mouth (DC4); salinity, sea-bed temperature, sediment particle size, sediment redox potential, residual chlorine and meiofaunal numbers were measured. The macrofauna is significantly suppressed at sites along the discharge canal, representing a community with half the number of species as at station DC4, comprising dense populations of a few dominant opportunistic species tolerant of thermal stress (e.g.Tubificoides, Cauleriella), and not those characteristic of organic pollution stress communities. The latter are regular summer immigrants in the creek, but persist only in low numbers if at all in the winter (e.g.Polydora ciliata). This suppression is the result of a 10°C temperature front between the heated discharge water and ambient estuarine water, passing over the sea bed with the ebbing and flooding tide four times each day. The residual gradient of mean temperature along the discharge canal causes some changes in the dominance of those species not eliminated by the temperature front. These temperature effects are expected to be localized, mainly in the area of sea-bed impingement of the discharge water; they are predicted to occur at any thermal discharge in tidal waters where the heated effluent contacts the sea bed.

Variation in morphological characters seen in a large collection of specimens of the genus Echinosigra from the Rockall Trough can be arranged in a continuous ontological series. This growth series embodied forms agreeing with Mortensen's (1907) descriptions of both E. phiale and E. paradoxa. Bivariate biometrical study showed a well-defined allometric relationship of test length to other body dimensions, particularly the width of the ‘head’ and the width and height of the ‘body’. Immature specimens corresponded to E. phiale whilst the typically elongated ‘neck’ of adults corresponding to E. paradoxa was developed, along with the opening of the genital pores, at around a test length of 20–24 mm.

The shell growth of small coastal Mytilus edulis L. was measured at three different constant low salinities over short periods of time. Growth was significantly depressed in 6·4 and 16‰ S but not in 22·4‰ S. Fluctuating salinities between 0 and 32‰ S depressed growth whether the fluctuations were of sinusoidal or abrupt form. After 1 week of preconditioning to constant 32‰ S the growth of coastal (Bangor) mussels was better than estuarine (Conwy) mussels. However, after two weeks’ preconditioning to 32‰ S the estuarine mussels displayed the best growth. In the fluctuating regime, both coastal and estuarine mussels exhibited poor growth rates. The long-term response of the shell growth of coastal M. edulis was followed over a period of 44 days. Salinities in the range 1·8–9·6‰ S were lethal to the mussels within 10 days. In 12·8 and 16‰ S growth was initially delayed but recovered eventually. There was a gradual decline in the growth rate of the mussels exposed to the higher salinities (19·2–32‰) and an improvement in the growth of the mussels living in lower salinities (12·8 and 16‰) to levels nearly matching that of the high salinity animals by day 37. This suggests that acclimation of the shell growth of M. edulis to salinities in the 12·8–28·8‰ S range was achieved by the mussels during the experimental period.

Annual cycles of development were studied in male and female Iceland scallops (Chlamys islandica). Volume fractions of each germ cell type and other gonadal tissue were determined by histological and stereological techniques. Spawning occurs during a short period in late June and early July.

The eyes of characins (Characidae), pike, pickerel (Esocidae) and wrasses (Labridae) have a red pigment epithelium. There is no melanin, the epithelial cells containing red particles (erythrosomes). These are tiny cylinders in the cell processes, and spherules in the cell bases. In characins and pike, the red cylinders participate in retinomotor activity. Cylinders are birefringent and act as waveguides; they transmit long wavelengths (> 550 nm). The red pigment has been extracted and purified. It appears to be the same in the three families. Ultraviolet, visible and infra-red spectra are presented.

Elminius modestus Darwin 1854 is a small, estuarine barnacle, until 1940 found only in New Zealand and southern Australia but now well established in Europe. Using electrophoresis, 22 enzymes were compared between 10 populations of E. modestus from Europe and three populations from the Antipodes. Fourteen enzymes gave consistent, scorable results at 19 loci, of which 10 were monomorphic. Contingency comparisons of allele frequencies at the polymorphic loci showed no significant difference within the European samples, within the Antipodean samplesand between the European and Antipodean samples. These results were discussed in the context ofboth the history of the spread of the species and its planktonic larval phase. It seems likely that the species spread to Australia by remote dispersal from New Zealand before 1832, and thatthe initial settlement in U.K. waters in the 1930s must have been large enough to establish thespecies successfully with a genome representative of that of the mother population, at least atthe loci examined.

Brumptiana lineata n.gen. et sp., from oro-nasal region of Raja, has a subcylindrical body, 2 pairs of eyes, 13 or 14 annuli per mid-body somite, 12 pairs of small pulsatile vesicles, 5 postcaecal fenestrae, 5 or 6 pairs of testes, a large muscular atrium with accessory glands, a thick-walled vagina and no receptaculum, conducting tissue or spermatheca.

An account is given of a commonly accepted method for measurement of the gill area of fishes. A number of practical hints are included together with some warning about possible sources of error. In particular, these include sampling methods and reduction of errors due to shrinkage. Emphasis is given to the importance of weighting in the calculation of gill area. Problems which arise in comparisons of gills from different species are discussed and attention is drawn to possible errors that can be introduced by the reduction of all data to a given body weight offish. Such dangers are especially present where comparisons are made between fishes which may differ in weight by as much as four orders of magnitude.

Tidal micro-growth bands were used to study the annual cycle of shell growth of individuals dated predominantly by the immersion mark technique, in three common intertidal gastropods Nucella lapillus (L.), Littorina littorea (L.) and Patella vulgata L. growing naturally in the Menai Straits. Growth in all three species approximated to the von Bertalanaffy type. All three species grew throughout the year, N. lapillus and L. littorea with early autumn and summer maxima, respectively, and P. vulgata with two maxima, one in late spring and the other in early autumn. P. vulgata alone were observed during exposure to a 6-day period of sub-zero air temperature in January 1982 when shell growth was totally interrupted. In Nucella and Littorina shell growth was found to be closely related to ambient temperature but in Patella there was a summer depression in growth. The file technique when combined with the immersion mark technique in date marking, was found to be inferior to the immersion mark technique on its own, since filing occasionally affected growth adversely.

From among the factors determining the seasonal changes in growth rate, temperature was of major importance. Seasonal reproduction may also have an influence, especially in P. vulgata where gametogenesis coincides with the depression in growth rate during summer months.

Alternative methods used in gastropod growth studies were compared. In the light of inadequacies associated with other methods of measuring growth, micro-growth band measurements in gastropods offers a new method with high resolution suitable both for short and long-term growth studies. It has potential also for ecological and physiological aspects of growth measurements.

The effects of copper and zinc on the daily shell growth of Mytilus edulis have been measured with a laser diffraction measuring technique accurate to 3 µm. The results show that within three days 10 ppb added copper has a significant inhibitory effect on shell growth. Longer term experiments have been undertaken which show that the effects of 10 ppb added copper become more severe as exposure time increases. Recovery of near normal shell growth does occur on transfer to clean sea water even after a 14 day exposure to this concentration. The effects of zinc on shell growth are less severe. Transferring animals from their natural environment to the laboratory causes a measurable disturbance of shell growth for up to a week.

The benthic fauna of a fly-ash dumping ground off the Northumberland coast has been studied in comparison with that of the surrounding natural sediments and a designated offshore spoil ground. Continued ash dumping has resulted in an increase in the silt fraction of the sediments, together with the appearance of pozzolanic aggregates at the sites of greatest dumping, some 3·5 km offshore. The sediments here show a more rapid decline in Eh values with depth. The natural benthic macrofauna represented a typical Echinocardium-filiformis community, giving way throughout the offshore spoil ground to a ‘ Paraonis-Magelona’ community dominated by smaller polychaete species more tolerant of poor sediments, while the stations at the centre of the ash dumping showed an anomalous community structure. The density of the fauna was reduced at the centre of the ash dumping, the worst station yielding only eight individuals in 0·2m. Contours of numbers of macrofaunal individuals and species, of faunistic diversity and biomass, and of meiofaunal numbers all show a similar pattern of some depression along the spoil ground, and greater depression at the ash-dumping centre. Statistical analyses confirm a significant negative correlation between faunistic parameters and ash content. Deposit-feeding species represented a lower proportion of the community at sites of high ash content. The negative correlation between faunistic diversity and ash content was statistically significant over an area of 43 km around the centre of the dumping. The faunistic impoverishment is considered mainly to be a response to the dumping per se, and options for reducing this effect are discussed.

A series of samples were taken during the period 1975–81 in successively deeper 250 m bathymetric zones between 400 and 2900 m depth in the Rockall Trough. The bathymetric centres of distribution of the gadoid species are at shallower depths than those of the morid species. Micromesistius poutassou and Gadiculus argenteus thori exploit the pelagic and benthopelagic resources at depths shallower than 750 m depth. Molva molva andMolva dypterygia dypterygia are primarily fish eaters, the latter occurring deeper than the former. Phycis blennoidesand the rarerAntonogadus macrophthalmus are epibenthic feeders. Among the morids, the benthopelagic feeding Antimora rostrata lives primarily at depths of 1500–2500 m. Halargyreus johnsonii and the more common Lepidion eques both live at 750–1000 m depth but exploit different resources in the benthopelagic and epibenthic regimes.

Using vital staining of neuromasts, followed by recovery, cupular growth rates of 1.4–4.1 μm/h were found in herring (Clupea harengus L.) larvae and 4.0 μm/h in juveniles. It seems likely that the cupulae are continually being shed and replaced.

The tenacity of the barnacle cyprids of Balanus balanoides (L.) during temporary adhesion to a variety of modified Perspex surfaces was tested using a sensitive microbalance. The Perspex panels were painted on the undersides with five colours of cellulose paint. Control measurements of the magnitude of temporary adhesion to clean slate panels were of the order of 2 × 10 N m. Untreated smooth Perspex panels and panels coated with an adsorbed layer of bovine serum albumen gave low figures of tenacity of the order of 0·8 × 10 N m. Roughening the panels with carborundum or treating with an adsorbed layer of barnacle extract protein resulted in higher tenacity measurements (1·0–1·8 × 10 N M), whereas the highest measurements were obtained when roughened Perspex panels were coated by an adsorbed layer of barnacle extract protein (1·6–2·2 × 10 N M). When the surfaces were made more attractive to barnacle cyprids by roughening or coating in barnacle protein the forces measured on dark coloured panels were higher than on lighter coloured panels. The results of the temporary adhesion measurements were closely paralleled by the numbers of cyprids found exploring the various surfaces during preference settlement experiments.