The burial mechanism of Crangon crangon was examined in detail using high-speed video-recording equipment. Four stages of burial were identified which were associated with three modes of burial. As the mode of burial changed, a change in the angle of substratum penetration was also noted.

The effect of particle size on the burying ability of three discrete size classes of shrimp was examined using both artificially graded and naturally occurring sediments. Particle size was found to be a major influencing factor on the degree of burial achieved by C. crangon, but no significant effect of shrimp size on burying ability was found over the size range tested.

A new species of a monogenean Isancistrum subulatae (Gyrodactylidae) has been discovered on the arms and tentacles of the cephalopod mollusc Alloteuthis subulata at Plymouth and I. loliginis, on the gills of the same host, has been re-discovered for the first time since its original description in 1912. I. subulatae, like other gyrodactylids, is viviparous, and has been shown by experiments to transfer to new hosts by contagion. In nature such transfers probably take place during copulation of the hosts and since the parasite may occur in numbers of several thousands per host, it may thereby constitute a venereal disease.

The surface of most fish is covered with a coating of slime which increases in amount after death when the fish is held at room temperature or stowed in ice. The slime has been examined by Dr. Ingvaldsen of the Prince Rupert Station who has found that 3 c.c. of this material contain 33.348 mg. of nitrogen of which 11.9 per cent is amino-nitrogen. It is poor in carbohydrates, but along with the mineral salts contained in seawater it appears to provide an excellent medium for bacterial growth. In the fresh fish, the slime is clear, of mucous consistency, and shows comparatively few organisms in stained films, but in fish which are not quite fresh the slime appears to be increased in amount, is opaque and increased in consistency. With increasing age the slime becomes yellowish and evil-smelling, and stained films show an enormous increase of bacteria. In the early stages of the work attempts were made to correlate the number of organisms in the slime with the age of the fish by making bacterial counts, but owing to the irregular distribution of the slime over the surface of the fish and the difficulty of making homogeneous suspensions the results were not very satisfactory, although gross changes-were readily detected.

The reproductive cycle of the purple clam (Amiantis purpurata) northern Patagonian population was studied throughout a 19-month period (September 1993–March 1995) using standard histological techniques and quantitative indicators (oocyte diameter distributions, oocytes per ocular field and relative oocyte area). In this species gametogenesis is a continuous process involving a complete gonadal restitution after the end of the reproductive season (no resting period). The proliferation phase occurs during the coldest half of the year (April to September) and maturation takes place during spring (September to December). Several partial emissions of gametes, with subsequent restitution of the gametogenic series, occur during the summer months. During the total maturation stage, oocytes never filled the whole alveolar area: maximum per cent of alveolar sections occupied by oocytes (46%) was observed in late spring–early summer. Implications of the reproductive pattern in the context of palaeogeographic history of northern Patagonia, and the isolation of this population are discussed.

Two species of Gracilaria, G. foliifera (Forsk.) Børg. and G. verrucosa (Huds.) Papenf., have been recorded from the Maritime provinces of Canada (South & Cardinal, 1970), although in recent years only G. foliifera var. foliifera is listed (South, 1976). These species are also known from the British Isles (Parke & Dixon, 1976). Chromosome counts of G. foliifera (Greig-Smith, 1954: as G. multipartita) and of G. verrucosa (Magne, 1964) from the European flora suggest these are distinct species.

The hermit crab Pagurus brevidactylus (Crustacea: Anomura: Paguridea) from the infralittoral area of Anchieta Island, Ubatuba, was characterized by population structure (size, sex ratio, reproduction and recruitment) and growth. Animals were collected monthly during 1999 by SCUBA diving. A total of 1525 individuals was collected (633 males and 892 females), 695 of them were ovigerous females. Overall sex ratio was 0·7:1 in favour of females. The crabs showed a unimodal distribution with males significantly larger than females. Ovigerous females were collected during all months and in high percentages from 1·0 mm of shield length, demonstrating intense and continuous reproduction. The longevity was approximately 24 months for males and 18 for females, which showed larger growth rate and reached sexual maturity earlier (two months) than males. The low number of males in this population may be due to the longer life span. Moreover, the sexual dimorphism favours males during the intra- and interspecific fights by shell, food, reproduction and territory. Females demonstrated a short life cycle and intense reproduction.

Sporophytes of Laminaria hyperborea have been grown under various conditions in the laboratory up to the stage of 1000 cells. Some larger plants have been observed after exposure in the sea. Growth was not increased by artificial aeration of the normally stagnant cultures, nor by introducing a dark period each day. The cell number per sporophyte was found to increase exponentially with time. In from 10- to 1000-celled plants the logarithm of the cell number was proportional to the logarithm of the plant length; the relationship corresponded to two-dimensional growth in the presence of increase in cell length. In this size range, when the plants were mainly monostromatic, the growth rate in the laboratory was 0.5 cell divisions/day and 22% increase in length/day. The growth rate of larger sporophytes, partly polystromatic, in the sea, was 10% increase in length/day. A sporophyte would take at least 54 days from the release of the parent zoospores to reach a length of 1 cm. The minimum continuous irradiance necessary for growth was 2 μg.cal/cm2sec (20 lux) at 10° C and 4–5μg.cal/cm2sec (40–50 lux) at 17° C. The saturating continuous irradiance was at about 100 μg.cal/cm2sec (1000 lux) at 10° C and about 150 μg.cal/cm2sec (1500 lux) at 17° C. Up to 360 μg.cal/cm2sec (3600 lux) from fluorescent lamps was not inhibitory. Growth at 15–20° C was approximately the same as at io° C.

Burrow wall sediment (BWS) and chamber debris (CD) of Pestarella tyrrhena burrows were isolated and compared to surrounding sediments differentiated into surface sediment (SS), deep ambient sediment (DAS) and embedded ambient organic debris (EAD). The focus was on the meiofauna community along with granulometric characteristics including organic content (OC) and bacterial abundances.

Clear trends were found for all parameters: the shrimp significantly increased OC within its burrow and affected grain size distributions. The oxidized burrow walls were highly consolidated, consisted of poorly sorted sediment enriched with silt and clay, and contained small particles of macrophyte debris, while coarse inorganic and organic particles >500 μm were concentrated in the CD. Bacterial abundances (epifluorescence microscopy direct counts, SYBR Gold staining) were positively correlated with OC and were significantly higher in BWS than in SS or DAS. Nematode numbers were elevated three-fold and foraminiferal densities by two orders of magnitude in BWS versus non-burrow sediments. Among the anoxic sediments (DAS, EAD, CD) meiofauna densities in CD were highest. Nematode community analysis (PCA, CANOCO) revealed considerable differences between BWS and SS. The BWS harboured more taxa and was dominated by deposit feeders, while in SS epistrate feeders prevailed.

These effects on different levels demonstrate the ability of P. tyrrhena to create a specific microenvironment within the burrow. The burrow walls were most influenced by the shrimp's activity, which corresponds to their nutritional role.

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were analysed from blood samples. Differences in heart rates, respiration rates and cortisol levels before and during the tagging events were investigated. An overall significant decrease of 31.5% in respiration rate was found during the tagging event period, while mature porpoises respired significantly more often than immature individuals. Though significant differences in heart rates were found for some individuals, no general significant change for all animals was detected. We found no correlation between cortisol concentration and either heart rate or respiration rate, nor did we find any relationships between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based on the factors investigated, on how to reduce stress during handling. However, pouring water over the animal and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises.

Egg capsules and intracapsular embryos of Rapana venosa were studied to determine the reproductive pattern of this invader species in the south-eastern Black Sea. Egg deposition of R. venosa in the laboratory at 25°C was described. Egg laying began in mid-June, reached a peak in July and ended in late August in 1996. The total number of the egg capsules per whelk ranged between 197 and 999 (mean 575 ±41). The mean length of the egg capsules was 13.26 mm. Each capsule contained between 124 and 1090 embryos with a mean of 555 ±10. Mean larval production per rapa whelk was about 392,931 ±42,731. The mean size of eggs produced was 213.8 μm. Five different stages of intracapsular development were observed. Embryos developed without nurse eggs. Veliger larvae completed their intracapsular development and hatched in 22 days at 25°C.

Line-transect estimates of abundance generally assume that distances and angles to animals are measured without error. Biased distance measurements will lead to corresponding bias in abundance estimates. Efforts to address this have been made, but measuring distance to cetaceans at sea remains problematic. Four distance-estimation experiments were conducted to explore relationships between estimated and measured distance. Heteroscedasticity was found in all four cases. Preliminary evidence suggested that an observer differed in the ability to judge distance to fixed, continuously-visible cues and ephemeral, cetacean cues, which calls into the question the common practice of using marker buoys as cetacean proxies in distance-estimation experiments. Two studies found visual estimates to be positively biased, and two studies found reticule measurements to be negatively biased. Suitable correction factors were developed to address systematic bias from visual estimates, but these varied widely among observers and were sometimes non-linear. Errors in three studies showed positive skew, suggesting that ranges were overestimated to a larger degree than they were underestimated. If reticule and photogrammetric measurements yield log-normally distributed errors generally, then a least-squares regression will always overestimate the correction factor, underestimate range, and overestimate abundance. Photogrammetric methods to measure range to cetaceans performed well, and their use is encouraged. When measurements cannot be made to all sightings, however, it is recommended that experiments be conducted that generate sufficient sample size (of the target species, across typical survey conditions, and beyond the maximum range that most estimates will be made during the survey) to assess error distributions, examine evidence for non-linearity, and to consider inter-observer differences. Distance experiments, and training on survey protocols, can be conducted using ships of opportunity prior to the beginning of a dedicated survey, which would improve observer efficiency while reducing the costs of dedicated vessel time.

For nearly fifty years a small marine organism has been cultured at the Marine Biological Association's Laboratory at Plymouth, mainly to be used as a food supply in rearing marine larval forms.

The cultures were originated by the late Dr E. J. Allen in 1907. The first record of these cultures and the methods used to maintain them were published by Allen & Nelson (1910) in a paper describing methods for obtaining persistent cultures of eighteen species of plankton diatoms. One of these cultures flourished so successfully that subcultures have been distributed to many laboratories and institutions both in Europe and America. This organism was named Nitzschia closterium W. Sm. forma minutissima. The authors, however, did not describe the organism or produce an illustration, so the combination can be considered only as a nomen nudum.

The tidal rhythm of swimming activity shown by the estuarine amphipod Corophium volutator can be entrained to cycles of temperature and immersion in the laboratory. The rhythm is phased to the period of increasing temperature, or to the time at which the animals are wetted by the artificial tide, and the activity maxima follow the Zeitgeber with a phase delay of about 5–6 h in each case. Entrainment to these variables alone is inadequate to account for ebb tide swimming in the natural state, and it is likely that the rhythm is normally entrained by a number of factors of variable significance.

At the present time only limited data about the release of organic matter by phyto-plankton in the marine environment are available (Antia, McAllister, Parsons, Stephens & Strickland, 1963; Fogg, Nalewajko & Watt, 1965; Hellebust, 1967; Jitts, 1967; Home, Fogg & Eagle, 1969; Anderson & Zeutschel, 1970; Thomas, 1971; Samuel, Shah & Fogg, 1971).

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.

Results are given of collections made with the stramin ring-trawl to study the vertical distribution of post-larval teleostean fishes throughoutthe period from daylight, through the hours of darkness, to daylight on July 15th-16th, 1924, and June 17th, 18th, and 19th, 1925. At the time of collecting in July, 1924, it was full moon ; in June, 1925, there was no moon.

In no case, except perhaps that of Sardina pilcliardus post-larvse, was there evidence of marked upward migration at night ; the general impression for most species was that while the type of distribution shown in daylight was somewhat modified at night, only very few individuals moved up to the surface layers. There was, however, a notable increase in numbers of certainspecies at all depths at night, whether this was an indication of a movement up from layers very close to the bottom is not known ; it will need many more observations before the exact significance of this can be fully understood.

The numbers of post-larvae taken were in the case of most species unfortunately very small on all occasions; it is not possible, therefore, to come to very definite conclusions.

A possible indication of the effect of moonlight was shown by the post-larval Callionymus lyra, for while in July, 1924, at the time of full moon they showed no upward movement at night, in June, 1925, with no moon a certain proportion reached the surface layers.

In this paper we present data on the organization of the territories in males of Lipophrys pholis during the breeding season. Data were collected during high tides by skin- and scubadiving and during low tides by direct inspection of nests. Our study area was located at Arrébida, Portugal. The main results are: (i) The territories of the breeding males of this species are temporary, being established each breeding season, (ii) The guarding males stay in the nest holes with the egg masses while the tide is low and are subjected to several hours of emersion in each tidal cycle, (iii) Even when the nests are submerged the fishes stay inside the nest for an average of 92% of the time. All the activities performed outside the nest correspond to an average of 27 minutes per day. (iv) There was a low frequency of territorial intrusions. Conspecific intruders released a significantly higher frequency of agonistic responses than did Coryphoblennius galerita. (v) Removal experiments showed that vacated territories are not occupied by other males during the same breeding season, (vi) Without the presence of the guarding male the eggs are slowly destroyed by predation and infection, but some eggs can still survive and hatch up to five days after the removal of the parental male. The results are discussed in terms of the probable costs and benefits of breeding intertidally.

The biology of Praunus flexuosus (Müller) is closely similar to that of P. neglectus (G. O. Sars). In both species the over-wintering population matures and breeds in the early spring and summer to produce a spring generation of young which are evident in the population in May or June. The members of the over-wintering population die off in July or August. Some members of the spring generation become sexually mature and breed in the early autumn. The progeny of this autumn breeding, along with the bulk of the spring generation, form the over-wintering population. These species are omnivorous feeding on animal and plant debris and also preying on small crustaceans, very frequently harpacticid copepods. The maximum brood size found in P. flexuosus was 63 and in P. neglectus was 81. The biology of the populations on the west coast of Scotland is briefly compared with that of populations in Port Erin, Isle of Man, in Norway and at Roscoff.

There is a long history of research on the ormer, Haliotis tuberculata L., in the Channel Islands. Stephenson (1924) was concerned with the reason for the diminution in the number of ormers off the shores of Guernsey and undertook a three months' investigation during the summer of 1923 and published brief notes on his results for further investigation. Tanner (1926) also made some brief notes on various aspects of the biology and ecology of the ormer which he said were based on 30 years' observation. In two reports (1929, 1937), Crofts dealt with aspects of bionomics, anatomy and early development of ormers with brief accounts of reproduction. Brehaut (1957) reported tagging experiments on the movement and growth of ormers and Forster (1967I gave more detailed information on these aspects, having earlier (1962) published a study on the quantitative measurement of the ormer population.

In shallow hypoxic sea water female shore crabs (Carcinus maenas (L.)) incubating eggs on their abdominal pleopods reverse the direction of normal ventilation, taking air in at the normally exhalant opening and bubbling it out via apertures at the base of the posteriormost pair of walking legs and hence over the developing egg mass. The ambient oxygen tension at which the behaviour is elicited and the percentage of total time it is performed are both dependent upon acclimation temperature. The oxygen tension at which the behaviour is first observed coincided at different acclimation temperatures with the critical oxygen tension below which oxygen consumption of the developing eggs became dependent on further reduction in . The bubbling of air during the emersion response is sufficient to raise the oxygen tension of the water surrounding the eggs and is thus an attempt by the parent animal to maintain the oxygen uptake of the developing young. If left in a standing body of hypoxic sea water release of larvae is deferred until well-aerated conditions next prevail. Thus if the berried female is trapped in a rock pool the encroaching tide may act as a releasing stimulus which is of adaptive significance to the dispersal and survival of the larvae. When female crabs submerged in warm water (25 °C) bubbled cool air past the egg mass this had no significant cooling effect. The thermal tolerance of the developing eggs was low, rate of oxygen uptake being limited by temperature rises above 25 °C.