The size of fish and squid prey of Loligo forbesi was investigated using otoliths, beaks and statoliths collected from stomach contents analysis of samples obtained from Scottish and Irish waters between 1990 and 1993. Loligo forbesi was found to consume a large range of prey sizes, but prey size was always less than the predator size. Season was shown to significantly influence the predator size-prey size relationship for sprat and sandeel prey, but this itself could be influenced by seasonal changes in the size of prey. Fish prey size increased with increased predator size up to a mantle length (ML) of 200 mm. Loligo forbesi of mantle length >200 mm consumed a range of prey sizes, with no clear increase in the size of prey. For most prey taxa the relationship between prey size and squid size was similar, the exceptions being dragonets and silvery pout. Cannibalism by L. forbesi was mostly limited to larger L. forbesi (>150 mm ML) feeding on smaller (20–50 mm ML) conspecifics.

The genus Ampelisca comprises more than 150 species and is one of the more important benthic genus of marine amphipods. New species are regularly added (Barnard & Agard 1986; Bellan-Santini & Marques, 1986; Goeke, 1987). Ampelisca are found from the intertidal zone to abyssal depths but most of them live on the continental shelf. In spite of many studies, it is often difficult to distinguish some species which are morphologically similar. In the last ten years, twenty-two species have been described from the north-eastern Atlantic (BellanSantini & Kaïm-Malka, 1977; Bellan-Santini & Dauvin, 1981, 1986; Dauvin & Bellan-Santini, 1982, 1985; Bellan-Santini & Marques, 1986). Materials come from MNHN of Paris collection, collected by Chevreux (1894–1924) (Dauvin & Bellan-Santini, 1985, 1986) and specimens collected during the last 25 years. All these new species are described from the Atlantic coast from northern Brittany to the Sahara and from the Mediterranean Sea.

The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.

With this note we contribute to the discussion on the appropriate level of taxonomic resolution required in benthic monitoring studies. In a set of multivariate analyses using data from different taxonomic levels and various data transformations we show that similar results are obtained on the levels of species to families, almost irrespective of the transformation used. For taxonomic levels above that of orders, transformation results in different plots and especially presence/absence transformation reduces the discrimination of sites. We recommend guiding the choice of transformation by biological considerations and adjusting the taxonomic sufficiency to the objective of each study.

Stafford (1913) rejected the view of many early workers (see Ryder, 1883, 1884; Huxley, 1883; Horst, 1886) that oyster larvae cemented themselves to the substratum with secretions of the mantle edge. He thought that the mantle margin could not be extended sufficiently to form the extensive area of cement that he found on the left valve of cemented larvae. Furthermore, he argued that the mantle could not secrete so much material in the short period that larvae took to cement. He deduced from the much reduced state of the ‘byssus gland’ in settled larvae that this gland was the source of the cement and suggested that the cement was spread over the shell by the foot. Nelson (1924), Prytherch (1934), Cole & Knight-Jones (1939) and Cranfield (19736, c) have clarified the role of the foot in cementing. Nelson (1924) also noted that cementing oyster larvae extended the mantle margin over the substratum but considered that this action spread the cement discharged by the foot and that the folds themselves did not secrete more material. The other authors, like Stafford, have dismissed or ignored any part the mantle folds might play in cementing.

The object in publishing these notes on the Spur-Dog, Acanthias vulgaris Risso, is to show the close resemblance, in the distribution of the sizes and sexes, between this fish and the Hake. The Hake will be dealt with in a future paper.

The work has been done during voyages in which the Hake has been the principal object of research. The data on Dogfish have therefore been collected at odd times during a very busy programme on the Hake, and this must be my apology for inadequacy or discontinuity in the figures presented. I would especially thank my colleague, Mr. W. Johnston, and my friend, Mr. C. E. D. Enoch, for their willing help in this entirely unofficial work; and Mr. J. Armitage Robertson for his help in the arrangement of the text.

Canopy-forming fucoid algae have an important role as ecosystem engineers on rocky intertidal shores, where they increase the abundance of species otherwise limited by exposure during low tide. The facilitative relationship between Ascophyllum nodosum and associated organisms was explored using a frond breakage experiment (100%, 50%, 25%, 0% intact-frond treatments) in southern England, to assess the consequences of disturbance. Understorey substratum temperature was on average 3°C higher in 0% and 25% intact-frond treatments than in plots with 50% and 100% intact fronds. Light (as PAR during low tide) doubled in 0% intact-frond treatments in comparison to other treatments (which had similar light levels). Mobile invertebrate species richness declined by on average 1 species per m2 in the treatments with only 25% and 0% intact fronds, and the abundance of Littorina obtusata declined by 2.4–4.2 individuals per m2 in the treatments with 25 and 0% intact fronds. Sessile taxa, including Osmundea pinnatifida and encrusting coralline algae, declined by half on average in the 0% intact-frond treatment. These results suggest that the ability of Ascophyllum to mediate environmental conditions to the understorey is the mechanism responsible for species distributed in the understorey (autogenic ecosystem engineering). The results of this study imply that a pulse disturbance resulting in a 50% breakage of Ascophyllum fronds significantly increases temperature and decreases the abundance of mobile invertebrates usually associated with Ascophyllum. Sessile taxa associated with Ascophyllum can, however, withstand disturbances down to 25% intact Ascophyllum fronds.

[The stages in the development of Calanus finmarchicus described and figured by Miss Lebour in the present paper were taken from culture jars given into my charge by Mr. L. R. Crawshay, when he left the Laboratory to undertake military duties in connection with the war. In one jar at that time the first copepodid stage, from eggs laid in the jar, had just been reached, and the technical details for the successful rearing of the animals had been mastered. The experiments had been conducted with great care, and all possible precautions had been taken to prevent contamination. Subsequently the experiments were repeated up to a certain point by myself and some additional stages obtained to complete the series.

The cultures were made in 2-litre glass beakers, containing “outside” sea-water filtered through a Berkefeld filter. In order to secure an even temperature the beakers stood in the circulating water of the Laboratory tanks, and a pure culture of the diatom Nitzschia closterium was used as food.—E. J. Allen.]

Starch gel electrophoresis of extracts of Siboglinum atlanticum showed that all five individuals tested have two acidic haemoglobin components and a strong α-naphthyl acetate esterase. There was individual variation in the position of the esterase. Low levels of amylase activity were found in the extracts but no trace of dehydrogenases for such important substrates as glucose-6-phosphate, lactate, malate, and glutamate could be revealed by standard histochemical methods as applied to zone electrophoresis. The high level of haemoglobin and the protein peculiarities of the Pogonophora are discussed in relation to experiments on respiration. It is concluded that Siboglinum haemoglobin functions at very low oxygen partial pressures and that the high level of haemoglobin dissolved in the blood plasma of pogonophores does not reflect a high level of oxygen consumption or activity. The meagre biochemical data at present available on the Pogonophora do not favour relationship of this phylum to the echinodtrm-chordate line any more than to the annelids or other invertebrate phyla.

INTRODUCTION

Largely as a result of studies by A. V. Ivanov, the phylum Pogonophora has become recognized by zoologists in the past decade (reviewed by Hyman, 1959, esp. pp. 208–27; Ivanov, 1963; E. C. Southward, 1963). Pogonophores are small, extremely vermiform animals, living in tubes partly im-bedded in mud or muddy sand; while in some areas they are sufficiently abundant to dominate the benthic fauna, their occurrence at great depths has made living pogonophores very difficult to obtain.

Two especially interesting problems associated with this newly recognized phylum are:(a) Pogonophora are the only group of free-living Metazoa without a gut at any stage in their development, and thus, the method of feeding and type of metabolism has been the subject of considerable speculation; (b) Pogonophora possess a few characteristics—e.g. a ventral heart and dorsal nerve cord—suggestive of the echinoderm-chordate line of evolution.

Akera bullata O. F. Müller is a tectibranch mollusc having a coiled external shell and a foot with lateral extensions used for swimming. At certain times of the year it swims actively, as was observed by Donovan, who writes that it ‘sports in its watery element with all the liveliness of a butterfly, and formed a pleasing object when kept alive in a glass of sea water’ (quoted by Montagu, 1803). Although sometimes abundant locally, it is not a mollusc often taken by the collector, even though it is a conspicuous object when swimming.

Although decorating behaviour is widely reported as a predator avoidance strategy among marine crabs, few studies have provided experimental evidence for this. Significance of decorating behaviour of the majid crab Tiarinia cornigera as antipredator response was examined by the field tethering and laboratory experiments. Survival of decorated crabs was significantly higher than that of non-decorated crabs after two days in an intertidal rock pool. In a laboratory experiment, crabs used more algae for decoration in the presence of predators (puffer fish) than when predators were absent. These data demonstrate that T. cornigera decorates with algae in response to predators to reduce predation pressure.

In the Acantharia, two different symbiotic algae are known. One is a dinoflagellate with a typical mesocaryon and the other, studied here, exhibits the characters of the Prymnesiophyceae (Haptophyceae).

Detailed descriptions of the non-motile and presumed premotile stages of this symbiont are given, with special reference to the haptonema, the scales and the plastid.

Comparisons are made with other members of the Prymnesiophyceae and the systematic position of the symbiotic alga is discussed.

1. Observations are given on the vertical distribution of adult Calanus finmarchicus in the daytime off Plymouth in July and August, 1931, as a result of collections made simultaneously with the photo-electric measurement of submarine illumination.

2. A series of nets, usually six, was towed simultaneously in such a manner that the depth of each net was known approximately.

3. The female Calanus in July preferred higher intensities of light than did the females in August; this change was coincident with a change in the Calanus population as shown by size measurements. A similar change in distribution and in population was shown by the males.

4. The females in July were living in intensities of 20,000 m.c. and more; but those in August were avoiding such high intensities. The males in July avoided intensities of 40,000 m.c. and over, while in August their upper limit was about 10,000 m.c.

The reproductive cycle of the Australasian barnacle Elminius modestus (Crustacea: Cirripedia) was studied at three sites within Whitegate Bay, Cork, Ireland over 15 months. At all three sites, there were seasonal trends in development of the male and female reproductive organs with, for example, the ovaries regenerating whilst eggs were being brooded. Throughout the year, significantly lower percentages of animals were brooding embryos at the site of a warm-water outfall than at another site nearby. The factors which may affect the reproductive cycle of E. modestus are discussed.

On British shores Pylaiella littoralis occurs in a large number of local populations which usually fall into one or other of four population groups. These populations often differ in habit, form, seasonal distribution, etc.

Two populations of P. littoralis from different environments have been studied experimentally and it seems from this that the morphological differences between the plants from the two populations are accompanied by physiological and genetical differences. Similar results have been obtained from experiments on other populations.

It is suggested that the numerous populations arise through the selective effect of all the prevailing environmental factors and are adapted to them.

The potentially large number of plant forms resulting from this process should not be described in terms of ‘orthodox’ taxonomy though they may possibly merit definition in terms of ‘experimental’ taxonomy in so far as some of the populations may constitute ecotypes as recognized in higher plants. Because it is possible for a single ecotype to be represented by more than one morphological type, however, the value of the ‘experimental’ system is regarded as doubtful.

A review of the verified reports to date of Architeuthis spp. showed that 33·9% (115 specimens) of worldwide reports were derived from the north-eastern Atlantic. The sex of each specimen, nature of the report, as well as the season and area of collection are presented. Biological data are presented on the two first males of Architeuthis sp. captured off the Iberian Peninsula. The first male (42 kg and 98 cm mantle length) was caught at 43°54·26′N 5°29·38′W by pair trawlers on 13 September 2002. Spermatophores ranged from 11 to 20 cm in length. The peculiar observation of other spermatophores embedded in the skin near the proximal part of the ventral, ventro-lateral and dorso-lateral arms is discussed. The second male (66 kg and 122 cm mantle length) was found floating on the surface off Gijón on 16 September 2003. Although mature, no spermatophores embedded in the skin were observed. A comparison was undertaken of several morphometric measurements between these two males and five other north-eastern Atlantic males from which data were available.

The phenomenon of epitoky in polychaetes, in which maturing individuals of benthic species undergo metamorphosis and then swim to the surface of the sea for spawning, has been extensively documented (see Fage & Legendre, 1927; Clark, 1961 for references). The death of individuals after spawning has been widely recorded and has been assumed to apply to all swarming species of polychaetes. However, Herpin (1925) recorded the survival of Pionosyllis lamelligera and Eusyllis blomstrandi after they had swarmed and spawned. He noted the loss of the swimming chaetae present at the time of spawning and that the individuals survived for some time. Goodrich (1933) found that individuals of Odontosyllis enopla survived swarming and considered that they might live to breed again.

The ciliated epithelial sensory cells of the tentacle papillae and of the concave epipodial sense organ (e.s.o.) surface of the trochids Margaretes helicinus, Gibbula cineraria, G. umbilicalis, Monodonta lineata, Diloma nigerrima and D. zealandica are primary sensory cells with intra-epithelial nuclei. The 5–7 cells of a single papilla bear many cilia. Each e.s.o. cell has one cilium surrounded by 8–9 specialized microvilli. Both kinds of sensory cell show structural similarities with known mechanoreceptors.

For centuries man has used lights to attract and concentrate fishes near the sea surface to aid their capture by nets or hooks (Ben-Yami, 1982). Underwater lights lowered into shallow seas are now regularly used to lure fish into set nets, large nets suspended beneath ships or into the vicinity of powerful pumps (Sidelnicov, 1981; Andreev, 1962; Nikonorov, 1969). Usually lights of more than 1 kw are used and such power requires a surface generator and strong insulated cable from the surface to the light. Although we know from these applications that some fish species are attracted by lights, the use of lights on trawls has not been developed for commercial exploitation or for research sampling. Perhaps such development has been discouraged by the safety problem and technical difficulties of providing electrical power on deck and handling heavily insulated conducting cable between the trawl and the generator. Lights have been used on commercial trawls with television in experiments to study fish reaction to trawls but such experiments were not concerned with finding the effect that lights might have on the quantity of fish caught and catches have not been analysed (A. Maclntyre, personal communication).

The pigments in the crowns of a number of sabellids and serpulids have been examined. The main pigments of sabellid crowns are ommochromes, but these pigments have not been found in serpulids. Both sabellids and serpulids also possess astaxanthin, and in Serpula, Protula and the sabellid Chone infundibuliformis it is to this pigment or an ester that the colour of the crown is due. The main carotenoids have been identified and the presence of a possible intermediate ketocarotenoid in amounts varying from one species to another suggests that the astaxanthin or astaxanthin ester is synthesized by the worms from carotene derived from the food. Pomatoceros has pink and blue pigments, and Galeolaria a similar grey-blue pigment which could not be identified with any known class of pigment. Neither these nor ommochromes have previously been found in annelids.