It has been concluded from studies of the elemental composition of the jaws of four Glycera species that a high concentration of copper is a structural feature of the glycerid jaw (Gibbs & Bryan, 1980). In Glycera gigantea Quatrefages, for example, the whole jaw when dried contains about 1–5% of copper, whilst zinc, calcium and magnesium, in roughly equal amounts, account for a further 1%. Copper is mainly confined to the distal half of the jaw and a concentration of 13% is present in the extreme tip; the other metals are more evenly distributed. Of non-metals, chlorine is concentrated in the distal tip along with the copper but sulphur is fairly evenly distributed and probably accounts for several percent of the dry weight.

In view of these findings, it was decided to investigate the Family Goniadidae, a group of worms that are closely related to the Glyceridae (and often included in that family) but which are readily separated by the different structure of the jaw apparatus and also of the parapodia (see Hartman, 1950). In goniadids the jaw apparatus consists of a pair of larger toothed jaws (macrognaths) plus dorsal and ventral arcs of smaller, H- and Y-shaped jaws (micrognaths), the whole forming a circle around the tip of the proboscis. The present observations were made on Goniada maculata Oersted, the only goniadid species present in the Plymouth area, and a total of four specimens, all about 5 cm in length, from different areas (Salcombe, Rame Grounds and Cawsand Bay: see Marine Biological Association, 1957) were examined.

Laboratory assessment of barnacle cyprid settlement showed that it was increased by a multiple of ∼6 and by a multiple of ∼3 by the pedal mucus produced by Patella vulgata and by Littorina littorea, respectively. Field experiments showed that pedal mucus produced by P. vulgata could increase cyprid settlement by a multiple of ∼4, but that there was no effect of the pedal mucus produced by L. littorea. Evaluation of the effect of pedal mucus coated with nitro-cellulose and various pedal extracts, on cyprid settlement, ascertained that there appeared to be no chemotactic or chemotaxic effect of pedal mucus on cyprid settlement. In contrast, the use of a physical analogue to pedal mucus, silicon grease, increased cyprid settlement by a multiple of ∼18.  Pedal mucus produced by P. vulgata and by L. littorea increased the time spent by cyprids in surface suitability testing by a multiple of ∼10 and ∼3, respectively. Only the pedal mucus produced by P. vulgata had any effect on the exploratory behaviour of cyprids increasing the time spent on this behaviour by a multiple of ∼3. Pedal mucus affects the settlement of cyprids through adhesive enmeshment, resulting in positive feedback to the mechanoreceptors housed in the antennules of cyprids, in what is effectively a settlement cascade. Pedal mucus produced by P. vulgata and L. littorea can affect the settlement of the majority of settling marine organisms through physical entrapment. Pedal mucus produced by L. littorea will have little, if any, effect on the settlement of organisms in the field whereas the pedal mucus produced by P. vulgata may be of major importance in determining the adult distribution patterns.

A new species of marine yeast Kluyveromyces penaeid (Saccharomycetoideae) was isolated from the heart tissue of a subadult shrimp Penaeus chinensis during tissue culture. The yeast grew well in seawater supplemented with 2% shrimp extract, but did not grow in chemically defined media. The vegetative cells reproduced by multilateral budding and formed rudimentary pseudohyphae occasionally. Asci were spheroidal and evanescent containing 2–13 smooth or oval ascospores. The best temperature for the yeast to grow was 20–25°C and 37°C was lethal. The yeast grew well in half to full strength seawater supplemented with shrimp extract, but did not grow in 25% strength seawater. The carbohydrate fermentation test was positive, the diazonium blue B and urea hydrolysis tests were negative.

Pilchard eggs were collected over a grid of 30 stations visited on 14 cruises from August 1969 to November 1970. The samples were taken with oblique tows of a 1 m terylene net at 4 knots, the average volume of water filtered being 750 m3. The formalin preserved eggs were graded into the series of stages described by Gamulin & Hure. No very early eggs were found, but from the occurrence of stage 2 eggs it is deduced that most spawning takes place in the early hours of darkness, between 20.00 and 24.00 h B.S.T.: some spawning must also occur all round the clock.

There were two main peaks of spawning, June-July and October-November, when large numbers of eggs were found inshore; the average numbers reached 196 per m2 water column in July and 30 per m2 water column in October. Smaller numbers of eggs were taken in the other months of the year, mostly offshore, and with a minimum in December–February. In the spring (March-May) the area sampled was well clear of the main area of spawning of pilchard in the approaches to the Channel, north or northwest of Ushant.

During the peak months no particular part of the sampling area appeared to be especially favoured for spawning.

The significance of the two main peaks of spawning is discussed in relation to the problem of recruitment of fish to the population. As an alternative to the accepted hypothesis that young pilchard move back to the Bay of Biscay for maturation it is suggested that some of them, at least, may survive and mature in the Channel.

Hermit crabs use different senses to search for and find shells. In most cases, chemical cues have been proven to act as a very efficient way of finding new shells. However, in intertidal environments, the water transports chemical signals in different directions and velocities may make it harder to track the source of the cue, so visual stimuli may be a more precise source of information. The hermit crab Calcinus californiensis shows a preference for the biconical shells of Stramonita biserialis, although the crabs may also use the less preferred shell of Nerita scabricosta. We were interested in exploring if C. californiensis identify the preferred shell species through vision in the absence of chemical stimuli. We presented both shell species to hermit crabs in two different sets of experiments. In one experiment, we presented to the hermit crabs real shells of N. scabricosta and S. biserialis, and in another, we presented only the silhouettes of the same shells. The hermit crabs discriminated between the real shells and the silhouettes of N. scabricosta and S. biserialis. Females attended with higher frequency to real shells and silhouettes of S. biserialis; while males attended more to shells and silhouettes of N. scabricosta. Although, larger males biased their attendance toward shells of S. biserialis. Our results show that visual perception may be more important than we have thought in intertidal animals.

Consistent with most other closely-related polychaete species which have been analysed cytogenetically to-date, Pomatoceros triqueter and P. lamarckii share an identical chromosome number (2n=24) and have a number of other karyotypic features in common. However, commensurate with their separate species status, their karyotypes differ at least in four chromosome positions as a result of structural chromosomal rearrangements. With a rDNA probe using the FISH technique, we have been able to demonstrate that the nucleolar organizer region (NOR) occurs at the same site on the same pair of chromosomes in the two species, which indicates that an inversion event is unlikely to have been the cause of the species variation in this particular case. Taken together, these karyotypic differences may be indicative of a chromosomal barrier to the formation of fertile offspring; an important feature for maintaining species integrity where the two forms occur sympatrically, such as in parts of south-west England.

A new species of sponge: Higginsia ciccaresei sp. nov. (Demospongiae: Desmoxyidae) is described from a marine cave of the Ionian Apulian coast (Mediterranean Sea). It lives in complete darkness, 250 m from the cave entrance, in a basin of anchialine waters of low salinity and relatively cool temperature. The spicule formation process seems to be affected by some of the peculiar characteristics of the ambient water, resulting in spicules of unusual shape and irregular surface. This is the second record of the genus Higginsia – which has a world-wide distribution – from the Mediterranean Sea. The hypothesis that H. ciccaresei could be considered as a tethyan relic which survived in the peculiar habitat of an anchialine cave is also suggested.

Recent investigations of the bottom fauna off Plymouth by Spooner (1959 a, b) have revealed the existence of a number of unusual and interesting crustaceans. The copepods collected during this investigation were very kindly placed at the disposal of the writer for study. A careful examination of the collection revealed the presence of a second and new species of Paramisophria Scott. This genus was established in 1897 by Scott on the basis of females collected in Scotland. Sars (1903) described the male for the first time. Paramisophria cluthae, the only species known previously, has been recorded from Plymouth.

Through a series of ichthyoplankton surveys carried out off central Chile, we characterize the offshore spawning and coastal nursery ground of the bigeye flounder Hippoglossina macrops. Eggs were collected in higher abundances over the continental shelf during late winter, over the shelf-break in mid spring, and at the continental slope in late summer, showing a seasonal depth gradient in spawning. No significant spawning was detected nearshore (less than 8 km offshore). Field data suggest a longitudinal progression from offshore to onshore of larval stages from preflexion to transformation stage. Finally, vertically stratified samples showed that eggs and larvae were present mainly in the upper 100 m. We discuss the potential onshore transport of early life stages of H. macrops through the compensatory flow of Equatorial Subsurface Waters that balances the surface offshore transport in the Ekman layer during upwelling events. Additionally, larval development from yolk-sac to transformation stage is briefly described.

Somewhere about 1914 D. J. Matthews maintained the sea-water in the Plymouth aquarium tanks at a pH value close to that of the outside sea-water by the addition of suitable quantities of sodium carbonate.

The Patagonian longfin squid Doryteuthis gahi has an annual life cycle with two seasonal cohorts (autumn and spring spawners). Earlier studies on the Patagonian shelf found a predominance of Euphausiacea in the D. gahi diet, but no studies to date have investigated differences between feeding spectra of the two cohorts or decadal diet shifts. The present study investigated differences in diet of D. gahi on the Patagonian shelf sampled two decades apart, and differences between seasonal cohorts. Classical stomach content analysis and generalized additive models were used to investigate and model the influence of mantle length, sampling period and spawning cohort on the diet. Results revealed an ontogenetic diet change from ~70% Frequency of Occurrence of Euphausiacea in small squid to more than 60% FO of fish and Cephalopoda at larger sizes. Cannibalism was also frequently observed. Euphausiacea were ingested more frequently and in higher amounts during the austral summer and therefore were consumed more by the autumn spawning cohort, whereas fish was more frequently fed upon during austral winter and also by the spring spawning cohort. Cannibalism was also recorded more in austral winter months but, contrary to feeding on fish, was more prevalent in the autumn spawning cohort. Increased predation of Munida gregaria was observed in 2020 compared with 2001. This study is an important step towards improving the knowledge of D. gahi's two seasonal cohorts, providing data that can be used for future ecosystem modelling.

Sponges are an integral part of marine benthic communities with a high-impact role in benthic–pelagic coupling processes, as an important source of food for demersal grazers and predators, as hosts of a highly diverse microbial biomass, and as bio-eroders. Sponges provide age-old (hygienic) services to humans and continue to be of interest in modern times as sources of an unprecedented array of useful substances.

Currently, little is known about the helminth fauna in sirenian species. Therefore, the objective of this study was to assess the frequency of infection by Pulmonicola cochleotrema in Antillean manatees (Trichechus manatus manatus), in the North-eastern region of Brazil. Between the years of 1989 and 2014, 88 manatees found on the North-eastern Brazilian coast were clinically examined. They included animals that were found dead, animals maintained in captivity and specimens reintroduced into conservation areas. During their physical examination, helminths present in necropsied carcasses and in reintroduced animals were collected, as well as faecal samples. Parasites were detected in 7.95% (7/88) of the animals; all specimens collected being identified as P. cochleotrema. Only adult manatees were infected, and in two cases clinical signs were observed. This is the first report on the occurrence of P. cochleotrema in Antillean manatees in the states of Paraíba and Sergipe, in the North-eastern coast of Brazil.

It is difficult to determine the weight or nitrogen content of the living tissues of an operculate barnacle without destroying it. It has been customary, there-fore, in ecological work to express growth in terms of various parameters determined from repeated measurements of the shell. Moore (1934) employed shell volume calculated from the height and basal diameters; others (Costlow & Bookhout, 1953, 1956; Mawatari, Hirosaki & Kobayashi, 1954a, b) have used the area of the basis. Most commonly, however, in growth-rate studies the length of the basis measured through the rostro-carinal axis has been used (Hatton, 1938; Barnes & Powell, 1953). Recently, working with animals cultured in the laboratory when the cast of an individual could be obtained subsequent to ecdysis, Costlow & Bookhout (1957) have used the size of the mouthparts as a measure of growth after first establishing their relation to body size. The space, both areal and volumetric, occupied by a sedentary animal is of primary importance in studies of its ecology and measurements of shell-size are, therefore, adequate for many purposes. For some aspects of growth and ecology it is, nevertheless, very desirable that the relation between such parameters and others, more directly connected with the living material, should be established.

A positive relationship between the number of locations where a species occurs and the average density of individuals across those locations has been found in a wide variety of taxa and has been described as one of the most general and widespread relationships in macro-ecology. However, exceptions to this general rule have been found and this study tested whether abundance–occupancy relationships exist within the cetacean community of the west coast of Scotland. Data were collected in 2003–2006 and occupancy rates were calculated and compared to two density indices (relative density of groups per km2 surveyed and relative density of individuals per km2 surveyed) for four cetacean species (harbour porpoise, bottlenose dolphin, common dolphin and minke whale). Significant positive intraspecific abundance–occupancy relationships were found for both relative density of groups per km2 and relative density of individuals per km2 for two out of the four cetacean species tested (harbour porpoise and minke whale). When the relationships between the different species were compared, all four were found to conform to the same interspecific relationship when relative density of groups was used as the density index. However, some species were found to conform to different relationships when relative density of individuals was used as the density index, potentially due to differences in social structure between cetacean species. These relationships mean that when cetaceans are at a higher density within an area, they also occupy a greater number of locations and vice versa. The existence of positive abundance–occupancy relationships in cetaceans has a number of potential implications for their conservation and management. In particular, it means that when a potential impact is likely to positively or negatively affect the size of the range of a species or population, such as noise pollution or climate change, it is likely to also affect the species' or population's abundance in the same direction. It also has implications for the design and extent of protected areas, such as marine protected areas; as such relationships could be used to determine the area required to maintain a viable population size.

Although many skates possess life history characteristics that may make them vulnerable to exploitation, the detailed biological information needed to enact effective management schemes is lacking for most species. The objectives of this study were to provide age, growth, and maturity estimates for the roughtail skate, Bathyraja trachura, from the eastern Bering Sea. Maximum age was estimated at 36 yr based on band pair counts in vertebral centra. Of the four growth models applied, the logistic model provided the best description of growth (asymptotic total length = 911 mm; growth coefficient = 0.131 yr−1). There was no evidence of difference in growth between males and females. Females attained maturity at larger sizes and older ages than males. The median size-at-maturity was estimated at 741 mm total length (TL) for males and 796 mm TL for females; median age-at-maturity was estimated at 21.1 yr and 24.7 yr for males and females, respectively. The results of this study may indicate a latitudinal pattern in size and growth, with individuals from the eastern Bering Sea growing more slowly and reaching higher maximum ages than previously reported for specimens collected off the western coast of the continental United States.

This study provides the first quantitative description of the emetic reflex (vomiting) in the dogfish (Scyliorhinus canicula) by using veratrine HC1 (lOmgkg−1, i.p.), the sodium channel activator as a stimulus. Vomiting occurred within 10 min of injection. The most notable features of the response in the correct temporal sequence were: (i) head shaking with wide gaping of the mouth; (ii) lowering of the ventral buccal cavity and expansion of the pharyngeal cavity; (iii) contraction of the gill arches, the buccopharyngeal musculature and lowering of the jaw rapidly followed by the expulsion of gastric contents (pieces of fish). The expulsion sequence (ii and iii) took ~ 1 s. The significance of the vomiting reflex in the dogfish is discussed in terms of its protective function and as a component of normal feeding to periodically eject indigestible food residues.

A long-established population of Jaera hopeana living ectocommensally upon Sphaeroma serratum is described from Wembury. This is a new record for the British fauna and is the northernmost record of a species which is found predominantly in the Mediterranean and Black Sea.

Traditional scale reading methods have been compared with [C]glycine uptake data to study scale growth in bass.

Both methods are capable of being used to age young fish and determine their rate of growth. The glycine incorporation rate is, however, of more value in studying shortterm changes in fish growth. When applied in this way, it indicates that the apparent isometric relationship between scale and body length is actually the sum of a number of allometric interactions. Some of the errors that can occur in scale reading are demonstrated by the application of these methods.

Monstrilloid copepods from a series of zooplankton samples collected in the coastal area of Miami, Florida, were examined taxonomically. Several adult females were found to belong to an undescribed species of Cymbasoma within the C. rigidum species complex. It can be distinguished from its congeners by the body proportions, shape of head, cephalic ornamentation pattern, genital double somite with straight lateral margins, and structure of the fifth legs, which have a small, inner lobe arising from the distal 1/5 of segment. This species shows intraspecific variability in some characters (i.e. shape of head, cephalic and genital ornamentation patterns); hitherto, such variation has been reported only in another species of Cymbasoma. Our finding supports the idea of the nominal species C. rigidum comprising a taxonomic complex with several undescribed taxa. The other species recorded in the area was Cymbasoma quadridens Davis, 1947. This was first described from a single male specimen collected in 1947 in Biscayne Bay, Florida, and has not been recorded thereafter. The type specimen now being unusable, this species is redescribed herein based on another topotypic male specimen collected near the type locality. New data are added about the armature of its antennules and swimming legs, cuticular ornamentation, and structure of the genital complex.