Whereas there is a wealth of literature on the feeding of herbivorous holo-plankton, notably copepods, feeding by herbivorous larvae of benthic animals has been somewhat neglected. This paper considers the functional feeding response of veliger larvae of Ostrea edulis L., Crassostrea gigas (Thunberg) and Mytilus edulis L. fed on several micro-algal species. It also provides some data on the influence of temperature on feeding, and assesses the energy needs of the larvae in relation to their potential ingestion rate and to the availability in the sea of micro-organisms on which they feed.

The American limpet, or slipper-limpet, known to naturalists as Crepidula fornicata, was introduced into England about 1880, being recorded at that time by Mr. B. S. Dodd in the Proceedings of the Malacological Society for 1893. Dodd, it is interesting to note, sounded even at that early time a warning note against the possible spread of this animal, and the probability of its becoming an enemy to the oyster farmer. There is no doubt that this limpet has been, and is probably still being introduced along with American oysters, on which it fixes itself. I have myself seen it unshipped along with oysters, but all the specimens I found had died recently. The spread of the limpet appears to have been very rapid on some grounds, as, for example, at West Mersea, where, since its appearance about eight years ago (from information obtained from local oyster fishermen), it has spread so that it is now more common than oysters.

In order to investigate seasonal changes in cetacean relative abundance, a series of surveys were conducted between the French mainland and Corsica. From February 2001 to February 2004, thirty similar transects were conducted monthly, using the same dedicated boat and a consistent sampling protocol, including visual observation and passive acoustic sampling. A total effort of 5759 km was sampled, conducted at the same speed and in good sighting conditions. Relative abundances of striped dolphins (Stenella coeruleoalba) and fin whales (Balaenoptera physalus) were determined using standard line-transect methodology. The relative abundance of striped dolphins peaked in May and September (>1.3×10-2 ind.km-1), while a consistent minimum value (<0.6×10-2 ind.km-1) was obtained from December to April. A maximum relative abundance of fin whales occurred in August with 5.6×10-2 ind.km-1 and decreased to almost zero from November to January. For sperm whale (Physeter macrocephalus), a long diver species, frequency and abundance indices were determined using acoustic sampling. The highest acoustic relative abundance was observed from August to October, with more than 2×10-2 ind.km-1. Environmental parameters (sea surface temperature and chlorophyll) were computed for the sampling area from remote sensing imagery and pooled on a monthly basis, to correlate with relative abundance indices of the three species.

There is clear evidence that marine reserves can be used as effective tools to foster the recovery of disturbed ecosystems. In the Azores, intense exploitation of the patellid limpets Patella candei and P. aspera has led to a rapid decline in their populations and subsequent collapse of the fishery in 1985. In 1993, legislation was passed to protect limpets, including the establishment of limpet protected zones (LPZs) where harvesting was completely prohibited. Outside LPZs, a seasonal fishing closure prohibited the harvesting of limpets from October to May. Here we examine the effect of such measures 16 years after they were put into practice. In each of the 3 years examined, limpet density, biomass and size were generally similar both inside and outside the LPZs. In addition, there were clear signs of exploitation as most individual limpets inside the LPZ were smaller than the legal catch size suggesting that illegal harvesting was taking place. Observations confirmed that illegal harvesting of limpets was common both inside and outside LPZs. Lack of enforcement of regulations is therefore a likely reason for the failure of legislation to protect limpet populations and facilitate stock recovery.

There is a considerable literature on the ecology of intertidal animals and a growing one on the sublittoral fauna. Largely because of the difficulty of taking samples in very shallow water, little attention has been paid to the continuation of the intertidal zonation below the low-water mark. Although incomplete in some respects, the results of the present survey are published, partly to help bridge the gap between studies of sublittoral and intertidal faunas, partly because it is unlikely that this survey will ever be completed and partly because the intertidal fauna of one of the bays is particularly well known. The work was begun in 1938 by one of the authors (A.M.) but was discontinued at the outbreak of the late war. Since 1949 further collections have been made and the identity of most of the species taken in the earlier sampling has been checked. The collections of animals and a full account of the results have been deposited in the Marine Laboratory at Millport.

The porcellanid crab Liopetrolisthes mitra is a common associate of the black sea urchin, Tetrapygus niger in north central Chile. The host-use pattern, population dynamics and reproductive pattern of L. mitra on sea urchins were examined between January 1996 and February 1997. Each month, between 60 and 95 per cent of all collected urchins hosted crabs, with the highest frequency of cohabitation occurring during the austral summer (January to March). Group sizes of crabs on individual urchins ranged from 1 to 25 crabs per host. The average density of crabs on the urchins ranged from 2 to 5.5 crabs per host. Large urchins were inhabited by crabs more frequently than small urchins but urchin size had no effect on the number or size of crabs. The sex ratio of adult crabs was ˜1:1 during most months. Reproduction occurred throughout the year but was most intense during the austral spring and summer (October to March), when the highest percentage of ovigerous females were found. Similarly, recruitment of L. mitra occurred throughout the year but reached a peak during austral summer and early autumn (January to May). All life stages of L. mitra including recently settled megalopae and reproductive adults were found on urchins. Size–frequency analysis indicated that many crabs live >1.5 years. The results of this study confirm that the association between L. mitra and T. niger is strong and persists throughout the benthic life of the commensal crab.

The morphology and ultrastructure of the heart and excretory system of the marine lamellibranch bivalve mollusc, Mytilus edulis (L.) are described. This paper supports the view that ultrafiltration of the blood occurs in the pericardial cavity. The auricles, pericardial glands and afferent oblique veins contain podocytes which are usually ascribed to the specific function of ultrafiltration. These cells are absent in the ventricle. The pericardial cavity communicates with the exterior via a very short (ca. 1–2 mm) renal tubule. The kidney comprises of a series of highly branched diverticula of this tubule and displays little or no structural differences throughout the organ. The kidney cells form a single layered columnar epithelium with a brush border, basal nuclei, infolded basal membranes and are characterized by the presence of many membrane-limited granules occupying as much as 20% of the cell volume. These granules and those of the podocytes are subsequently shed into the lumen of the kidney tubule and are excreted in the urine which is therefore largely paniculate.

Data are presented confirming the belief of Harvey and of Redfield that, in broad outline, the ratio of nitrate-nitrogen and of phosphate-phosphorus in the sea and of nitrogen and phosphorus in marine plankton lies within fairly narrow limits. The ratio approaches twenty to one when expressed in terms of milligram-atoms or nine to one by weight. There are however deviations from this broad generalization, but they do not provide a reason for discarding the concept but rather suggest close examination of the causes of the variations.

Experiments have been reported recently (Atkins, Jenkins & Warren, 1954) in which the relative concentration of suspended matter at different depths in the sea was determined by filtering samples of water through collodion membranes and measuring the relative albedos. Also reported in the same paper are the results of a series of observations of the visual range of a Secchi disc at station E1 in relation to the concentration of phytoplankton.

The endostyle of Amphioxus has for a long time been regarded as homologous with the subpharyngeal gland of the cyclostome ammocoete larva. This view was promulgated by Müller (1873) and by Dohrn (1886), and has been supported by many workers, for example Leach (1944). The metamorphosis of portions of the subpharyngeal gland to the thyroid gland of the adult lamprey was followed by Marine (1913), and uptake of radioactive iodine by certain cell elements of the subpharyngeal gland was demonstrated by Gorbman & Creaser (1942). At the same time the latter workers failed to establish the presence of iodine in the endostyle of Amphioxus by autoradio-graphic techniques. Gorbman (1941), however, showed that the ascidian Perophora annectans could accumulate radioactive iodine in its pharyngeal stolon but not in its endostyle. The part of the pharyngeal stolon involved is derived from the endostylar region of the pharynx. Recently, Sembrat (1953) has shown that endostyles of Amphioxus implanted into larval axolotls accelerated their metamorphosis, and concludes from this that the organs contain an ‘active substance (or substances) which may evoke amphibian metamorphosis similarly to the active hormone of the thyroid gland. It is probable that the substance is not identical with thyroxin which may be inferred from the fact that the endostyle’ of Branchiostoma does not accumulate radioactive iodine (Gorbman & Creaser, 1942) as well as from its different and tolerably little efficacious influence on the amphibian metamorphosis as compared with typical metamorphic symptoms induced by the thyroid gland.’ The work about to be described has demonstrated the presence of iodine in the endostyle, and suggests, further, that it is present in the form of a ‘thyroid hormone-like’ substance, thereby supporting Sembrat's general conclusion.

It has long been known that sea water is alkaline and numerous determinations of its alkalinity have been made. The method adopted was the usual one for mixtures of carbonates and bicarbonates, or some modification of it. Those waters which give no colour with phenolphthalein contain bicarbonate only, but for the most part ocean waters have a small amount of carbonate also. Owing to the presence of larger amounts of carbonates and bicarbonates the reaction of sea water is more stable than that of rain or river water, inasmuch as it has a greater alkaline reserve which acts as a “buffer.” The significance of this has been pointed out by Moore, Prideaux, and Herdman (1915) and by other workers. The measurement of alkalinity was carried out by the above named using N/100 hydrochloric acid and titrating to the end points with phenol phthalein and methyl orange. The results are recorded in cubic centimetres of centinormal acid per 100 c.c. of sea water; this is convenient as it is what is measured directly, but others adopt the perhaps more rational notation of milligram equivalents of hydroxyl per litre (Buch, 1914). One cubic centimetre of N/100 acid per 100 c.c. corresponds to 0.1 milligram equivalent per litre. Some workers on fresh waters, Birge and Juday (1911) for example, consider water as acid if it contains more carbon dioxide than that sufficient to convert the carbonate into bicarbonate, and titrate back to a pink with phenolphthalein. Their acid water is, however, still alkaline to methyl orange.

Sexual maturation and spawning was followed in one and two year old rope cultured mussels (Mytilus edulis) from April to December. Development of gonad and storage tissue was followed using descriptive categories from histology, and development of total soft tissue was followed using meat yield and condition index.

Both age groups were mature both during spring and autumn and had similar patterns of spawning and maturation. April and May were characterized by scattered spawning activity and accumulation of storage reserves at the same time, resulting in relative constant condition indices during this period. This was followed by ripening of the gonads and an increase in condition index that culminated in a spawning in late June. Parts of the population then entered a resting phase, while a part of the population underwent new maturation towards an autumn spawning in September. In December all the mussels had started the winter maturation.

Condition index and meat yield were higher throughout the season in the one year old mussels. This was probably due to the sum of several factors, including differences in specific feeding rates and biomass density, rather than spawning.

The present study is the first to compare the reproductive patterns over time of one and two year old mussels with reliable age determination, and provide information that there are no obvious differences in neither timing of gonad development nor spawning patterns between the age-classes.

The status of our knowledge of the organic nutrition of algae has been summarized in tabular form from time to time. Albritton (1954) listed a mere 14 taxa of pigmented algae as having been examined from this point of view. Eight of the 14 were species of Euglena and only ‘Nitzschia dosterium' (= Phaeodactylum tricornutum Bohlin) was marine. This paucity of information reflected in part the lack of suitable denned culture media as prerequisites of nutritional experiments. By the early 1960s this lack had been overcome to a large extent (see, for example, Provasoli, McLaughlin & Droop, 1957) and Thomas (1968) could list some 280 species, both freshwater and marine, on which nutritional work in terms of organic requirements had been undertaken. The vitamin requirements (or lack of them) of most of these species were known, but knowledge of their ability to grow in the dark on organic carbon sources and of their ability to utilize different nitrogen sources in the light was fragmentary. It still is, despite the fact that some of the gaps in Thomas's tables have been subsequently filled and the list of species has been extended.

The present study investigates correlations between abundances of nematodes (at the genus level) and benthic microalgae on an intertidal mudflat in the Westerschelde Estuary (south-west Netherlands), using both multi- and univariate methods. Two sample series, covering surface areas of 10 cm2 (meioscale) and 1.25 cm2 (microscale) per sample were analysed. Trophic type analysis indicated that an average of 31% of the nematode community were candidate grazers of microalgae. Multivariate data analysis indicated that only a limited part of the variation in the nematode data could be explained in relation to pigments. Total nematodes did not show any correlation with the pigment data. On the meioscale, the genera Tripyloides and Calyptronema correlated negatively with chlorophyll concentration (chl-a and chl-c, respectively), while Prochromadorella correlated positively with the ratio of fucoxanthin to chl-a, a ratio which at the present sampling site can be considered to be a measure of the proportion of diatoms in the total microalgal standing stock. On the microscale, up to ten genera, comprising 76% of total nematode numbers, were correlated with pigments. A majority (74%) correlated specifically with the ratio of fucoxanthin to chl-a, while much fewer nematodes showed a direct correlation to pigment concentrations. Whereas many of these correlations could be explained in terms of direct trophic links, several others probably represented indirect relationships, trophic or other. Food densities may be less important structuring factors of nematode communities on tidal flats than relative abundances of particular food sources. It is suggested that nematodes actively migrate towards ‘optimal’ food patches, and that this dynamic aspect of nematode–microalgae correlations is best revealed at a spatial-scale small enough to allow a rapid response of nematodes to changes in adjacent patches. Apparently, the microscale used in the present study is more adequate for the study of such intricate interactions than the meioscale.

In order to estimate the degree of implantation of excavating sponges in the oyster populations from the littoral zone at Blanes (north-western Mediterranean Sea), a representative sample of oysters (Ostrea edulis) was collected from depths between 0.5 and 4 m in 1986. All oysters were infested by the excavating sponges Cliona viridis and Cliona celata. Infestation affected always and exclusively the lower valve always reaching the inner side. The degree of infestation proved to be independent of oyster size and weight. Colonization by contact was considered the main means of dispersion of these sponges within the oyster population. Cliona viridis and C. celata emerged as the single excavating species able to effectively compete with other non-excavating or excavating organisms when trying to colonize the particular calcareous substrate provided by oyster shells in the north-western Mediterranean Sea.

This study confirms the diet and determines the trophic position of the bentfin devil ray (Mobula thurstoni) and spinetail devil ray (Mobula japanica) in the south-west Gulf of California. There has been an active fishery in the area for these filter-feeding elasmobranchs, which are highly susceptible to exploitation due to low fecundity and long lifespan. However, information on their basic biology is scarce. δ13C and δ15N values of devil rays and zooplankton (sorted according to trophic level: herbivores, carnivores and omnivores) were determined over a period of 11 months, to allow for isotopic temporal variations in isotopic signals at the base of the food web. On the basis of fractionation factors we determined that bentfin and spinetail devil rays fed mainly on Nyctiphanes simplex, the most abundant euphausiid in neritic waters of the Gulf of California. The trophic positions obtained for the devil rays correspond to second level consumers.

In early June 1988, an extensive bloom of Phaeocystis sp. (29xlO6 cells 1−1) was observed in the eastern Irish Sea along the North Wales coast. Chlorophylls, carotenoids, free amino acids, fatty acids, vitamin C, carbon and nitrogen were measured in particles from three size categories (<22 μm, 22–100 μm and 100–200 μm) at a station 13 miles off the coast line. Phaeocystis sp. formed 99% of the total particle stock below 22 μm and was characterized by (1) the presence of chlorophyll c3, (2) the dominance of fucoxanthin over 19'- acyloxyfucoxanthins, (3) the presence of C18:5 fatty acid at trace levels and (4) different proportions of amino acids compared to those measured in particles greater than 22 μm. These larger particles were dominated by diatoms, dinoflagellates and ciliates. The poor nutritional value of Phaeocystis sp. for herbivorous zooplankton was characterised by its low content of polyunsaturated fatty acids and vitamin C. Comparison between the chemical composition of Phaeocystis sp. and copepod faecal pellets showed that the copepods were feeding predominantly on other phytoplankton.

Like most heavy metals, cadmium is only found in minute amounts in natural sea water. Krauskopf (1956) stated that cadmium concentration of normal sea water ranges from 0.032 to 0.075 PPb (μg/l−1) while Goldberg (1965) gave a somewhat higher value of 0.11 ppb. Cadmium concentrations determined by Preston (1973) for the North-East Atlantic Ocean range from <0.01 to 0.41 ppb, and similar values have been found by Windom & Smith (1972) in the West- and Chester & Stoner (1974) in the South Atlantic Ocean (0.04–0.17 ppb).

Gobies emit sounds during different stages of reproduction, including courtship, pre-spawning events (in the nest) and spawning. The breeding sounds of the painted goby Pomatoschistus pictus and associated courtship behaviour were recorded in captivity and described for the first time. Males emitted thump-like sounds mainly when displaying alone in the nest and produced drumming sounds outside the nest. Thumps have never been reported for other species of the genus Pomatoschistus. Thumps were short (~80 ms) very-low frequency (below 100 Hz) non-pulsed sounds, whereas drums were longer (hundreds of ms) and consisted of low frequency (~300 Hz) pulse trains. Thump characteristics varied significantly among males but also showed high within-male variability. The frequency of thump emissions and courtship behaviour (total number of courtship displays, lead and nest display) were positively correlated with male size but not with male somatic condition. Thump bursts emitted during nest displays were significantly longer than when emitted with other behaviours. These results suggest that larger males courted females more intensively, both with visual and acoustic displays, than smaller ones.

Ship strikes of large whales cause mortalities worldwide, but there is uncertainty regarding the frequency and species involved. We examined 130 records (from 1980–2006) of large whale strandings in Washington State. Nineteen strandings (seven species) had evidence of ship-strikes. Fin whales (Balaenoptera physalus) had the highest incidence of ante-mortem ship strike (five of seven, with the remaining two possibly post-mortem) and all but one occurring since 2002. Six grey whales (Eschrichtius robustus) suffered ‘possible ship strike’ injuries, likely the result of their large numbers in the area, rather than high levels of ship strikes. Only one possible ship-struck humpback whale was recorded, despite concentrations of humpbacks feeding within shipping lanes in this region. This study shows dramatic differences in occurrences of ship-struck large whales by species, which we believe results from a combination of species' vulnerability to ship strikes, and how likely a struck whale is to be caught up on the bow of a ship and brought to waters where it can be examined.